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Diffstat (limited to 'net/sctp/sm_statefuns.c')
| -rw-r--r-- | net/sctp/sm_statefuns.c | 5238 |
1 files changed, 5238 insertions, 0 deletions
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c new file mode 100644 index 00000000000..278c56a2d07 --- /dev/null +++ b/net/sctp/sm_statefuns.c @@ -0,0 +1,5238 @@ +/* SCTP kernel reference Implementation + * (C) Copyright IBM Corp. 2001, 2004 + * Copyright (c) 1999-2000 Cisco, Inc. + * Copyright (c) 1999-2001 Motorola, Inc. + * Copyright (c) 2001-2002 Intel Corp. + * Copyright (c) 2002 Nokia Corp. + * + * This file is part of the SCTP kernel reference Implementation + * + * This is part of the SCTP Linux Kernel Reference Implementation. + * + * These are the state functions for the state machine. + * + * The SCTP reference implementation is free software; + * you can redistribute it and/or modify it under the terms of + * the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * The SCTP reference implementation is distributed in the hope that it + * will be useful, but WITHOUT ANY WARRANTY; without even the implied + * ************************ + * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + * See the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GNU CC; see the file COPYING. If not, write to + * the Free Software Foundation, 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + * + * Please send any bug reports or fixes you make to the + * email address(es): + * lksctp developers <lksctp-developers@lists.sourceforge.net> + * + * Or submit a bug report through the following website: + * http://www.sf.net/projects/lksctp + * + * Written or modified by: + * La Monte H.P. Yarroll <piggy@acm.org> + * Karl Knutson <karl@athena.chicago.il.us> + * Mathew Kotowsky <kotowsky@sctp.org> + * Sridhar Samudrala <samudrala@us.ibm.com> + * Jon Grimm <jgrimm@us.ibm.com> + * Hui Huang <hui.huang@nokia.com> + * Dajiang Zhang <dajiang.zhang@nokia.com> + * Daisy Chang <daisyc@us.ibm.com> + * Ardelle Fan <ardelle.fan@intel.com> + * Ryan Layer <rmlayer@us.ibm.com> + * Kevin Gao <kevin.gao@intel.com> + * + * Any bugs reported given to us we will try to fix... any fixes shared will + * be incorporated into the next SCTP release. + */ + +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/ip.h> +#include <linux/ipv6.h> +#include <linux/net.h> +#include <linux/inet.h> +#include <net/sock.h> +#include <net/inet_ecn.h> +#include <linux/skbuff.h> +#include <net/sctp/sctp.h> +#include <net/sctp/sm.h> +#include <net/sctp/structs.h> + +static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + struct sctp_chunk *chunk, + const void *payload, + size_t paylen); +static int sctp_eat_data(const struct sctp_association *asoc, + struct sctp_chunk *chunk, + sctp_cmd_seq_t *commands); +static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, + const struct sctp_chunk *chunk); +static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const struct sctp_chunk *chunk, + sctp_cmd_seq_t *commands, + struct sctp_chunk *err_chunk); +static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands); +static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands); +static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); + + +/* Small helper function that checks if the chunk length + * is of the appropriate length. The 'required_length' argument + * is set to be the size of a specific chunk we are testing. + * Return Values: 1 = Valid length + * 0 = Invalid length + * + */ +static inline int +sctp_chunk_length_valid(struct sctp_chunk *chunk, + __u16 required_length) +{ + __u16 chunk_length = ntohs(chunk->chunk_hdr->length); + + if (unlikely(chunk_length < required_length)) + return 0; + + return 1; +} + +/********************************************************** + * These are the state functions for handling chunk events. + **********************************************************/ + +/* + * Process the final SHUTDOWN COMPLETE. + * + * Section: 4 (C) (diagram), 9.2 + * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify + * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be + * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint + * should stop the T2-shutdown timer and remove all knowledge of the + * association (and thus the association enters the CLOSED state). + * + * Verification Tag: 8.5.1(C) + * C) Rules for packet carrying SHUTDOWN COMPLETE: + * ... + * - The receiver of a SHUTDOWN COMPLETE shall accept the packet if the + * Verification Tag field of the packet matches its own tag OR it is + * set to its peer's tag and the T bit is set in the Chunk Flags. + * Otherwise, the receiver MUST silently discard the packet and take + * no further action. An endpoint MUST ignore the SHUTDOWN COMPLETE if + * it is not in the SHUTDOWN-ACK-SENT state. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_ulpevent *ev; + + /* RFC 2960 6.10 Bundling + * + * An endpoint MUST NOT bundle INIT, INIT ACK or + * SHUTDOWN COMPLETE with any other chunks. + */ + if (!chunk->singleton) + return SCTP_DISPOSITION_VIOLATION; + + if (!sctp_vtag_verify_either(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* RFC 2960 10.2 SCTP-to-ULP + * + * H) SHUTDOWN COMPLETE notification + * + * When SCTP completes the shutdown procedures (section 9.2) this + * notification is passed to the upper layer. + */ + ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, + 0, 0, 0, GFP_ATOMIC); + if (!ev) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); + + /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint + * will verify that it is in SHUTDOWN-ACK-SENT state, if it is + * not the chunk should be discarded. If the endpoint is in + * the SHUTDOWN-ACK-SENT state the endpoint should stop the + * T2-shutdown timer and remove all knowledge of the + * association (and thus the association enters the CLOSED + * state). + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); + + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + + SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); + + return SCTP_DISPOSITION_DELETE_TCB; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Respond to a normal INIT chunk. + * We are the side that is being asked for an association. + * + * Section: 5.1 Normal Establishment of an Association, B + * B) "Z" shall respond immediately with an INIT ACK chunk. The + * destination IP address of the INIT ACK MUST be set to the source + * IP address of the INIT to which this INIT ACK is responding. In + * the response, besides filling in other parameters, "Z" must set the + * Verification Tag field to Tag_A, and also provide its own + * Verification Tag (Tag_Z) in the Initiate Tag field. + * + * Verification Tag: Must be 0. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_chunk *repl; + struct sctp_association *new_asoc; + struct sctp_chunk *err_chunk; + struct sctp_packet *packet; + sctp_unrecognized_param_t *unk_param; + struct sock *sk; + int len; + + /* 6.10 Bundling + * An endpoint MUST NOT bundle INIT, INIT ACK or + * SHUTDOWN COMPLETE with any other chunks. + * + * IG Section 2.11.2 + * Furthermore, we require that the receiver of an INIT chunk MUST + * enforce these rules by silently discarding an arriving packet + * with an INIT chunk that is bundled with other chunks. + */ + if (!chunk->singleton) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* If the packet is an OOTB packet which is temporarily on the + * control endpoint, respond with an ABORT. + */ + if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) + return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); + + sk = ep->base.sk; + /* If the endpoint is not listening or if the number of associations + * on the TCP-style socket exceed the max backlog, respond with an + * ABORT. + */ + if (!sctp_sstate(sk, LISTENING) || + (sctp_style(sk, TCP) && + sk_acceptq_is_full(sk))) + return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); + + /* 3.1 A packet containing an INIT chunk MUST have a zero Verification + * Tag. + */ + if (chunk->sctp_hdr->vtag != 0) + return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); + + /* Make sure that the INIT chunk has a valid length. + * Normally, this would cause an ABORT with a Protocol Violation + * error, but since we don't have an association, we'll + * just discard the packet. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Verify the INIT chunk before processing it. */ + err_chunk = NULL; + if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, + (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, + &err_chunk)) { + /* This chunk contains fatal error. It is to be discarded. + * Send an ABORT, with causes if there is any. + */ + if (err_chunk) { + packet = sctp_abort_pkt_new(ep, asoc, arg, + (__u8 *)(err_chunk->chunk_hdr) + + sizeof(sctp_chunkhdr_t), + ntohs(err_chunk->chunk_hdr->length) - + sizeof(sctp_chunkhdr_t)); + + sctp_chunk_free(err_chunk); + + if (packet) { + sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, + SCTP_PACKET(packet)); + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); + return SCTP_DISPOSITION_CONSUME; + } else { + return SCTP_DISPOSITION_NOMEM; + } + } else { + return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, + commands); + } + } + + /* Grab the INIT header. */ + chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; + + /* Tag the variable length parameters. */ + chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); + + new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); + if (!new_asoc) + goto nomem; + + /* The call, sctp_process_init(), can fail on memory allocation. */ + if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, + sctp_source(chunk), + (sctp_init_chunk_t *)chunk->chunk_hdr, + GFP_ATOMIC)) + goto nomem_init; + + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); + + /* B) "Z" shall respond immediately with an INIT ACK chunk. */ + + /* If there are errors need to be reported for unknown parameters, + * make sure to reserve enough room in the INIT ACK for them. + */ + len = 0; + if (err_chunk) + len = ntohs(err_chunk->chunk_hdr->length) - + sizeof(sctp_chunkhdr_t); + + if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) + goto nomem_ack; + + repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); + if (!repl) + goto nomem_ack; + + /* If there are errors need to be reported for unknown parameters, + * include them in the outgoing INIT ACK as "Unrecognized parameter" + * parameter. + */ + if (err_chunk) { + /* Get the "Unrecognized parameter" parameter(s) out of the + * ERROR chunk generated by sctp_verify_init(). Since the + * error cause code for "unknown parameter" and the + * "Unrecognized parameter" type is the same, we can + * construct the parameters in INIT ACK by copying the + * ERROR causes over. + */ + unk_param = (sctp_unrecognized_param_t *) + ((__u8 *)(err_chunk->chunk_hdr) + + sizeof(sctp_chunkhdr_t)); + /* Replace the cause code with the "Unrecognized parameter" + * parameter type. + */ + sctp_addto_chunk(repl, len, unk_param); + sctp_chunk_free(err_chunk); + } + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); + + /* + * Note: After sending out INIT ACK with the State Cookie parameter, + * "Z" MUST NOT allocate any resources, nor keep any states for the + * new association. Otherwise, "Z" will be vulnerable to resource + * attacks. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); + + return SCTP_DISPOSITION_DELETE_TCB; + +nomem_ack: + if (err_chunk) + sctp_chunk_free(err_chunk); +nomem_init: + sctp_association_free(new_asoc); +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Respond to a normal INIT ACK chunk. + * We are the side that is initiating the association. + * + * Section: 5.1 Normal Establishment of an Association, C + * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init + * timer and leave COOKIE-WAIT state. "A" shall then send the State + * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start + * the T1-cookie timer, and enter the COOKIE-ECHOED state. + * + * Note: The COOKIE ECHO chunk can be bundled with any pending outbound + * DATA chunks, but it MUST be the first chunk in the packet and + * until the COOKIE ACK is returned the sender MUST NOT send any + * other packets to the peer. + * + * Verification Tag: 3.3.3 + * If the value of the Initiate Tag in a received INIT ACK chunk is + * found to be 0, the receiver MUST treat it as an error and close the + * association by transmitting an ABORT. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + sctp_init_chunk_t *initchunk; + __u32 init_tag; + struct sctp_chunk *err_chunk; + struct sctp_packet *packet; + sctp_disposition_t ret; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the INIT-ACK chunk has a valid length */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + /* 6.10 Bundling + * An endpoint MUST NOT bundle INIT, INIT ACK or + * SHUTDOWN COMPLETE with any other chunks. + */ + if (!chunk->singleton) + return SCTP_DISPOSITION_VIOLATION; + + /* Grab the INIT header. */ + chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; + + init_tag = ntohl(chunk->subh.init_hdr->init_tag); + + /* Verification Tag: 3.3.3 + * If the value of the Initiate Tag in a received INIT ACK + * chunk is found to be 0, the receiver MUST treat it as an + * error and close the association by transmitting an ABORT. + */ + if (!init_tag) { + struct sctp_chunk *reply = sctp_make_abort(asoc, chunk, 0); + if (!reply) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); + return SCTP_DISPOSITION_DELETE_TCB; + } + + /* Verify the INIT chunk before processing it. */ + err_chunk = NULL; + if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, + (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, + &err_chunk)) { + + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + + /* This chunk contains fatal error. It is to be discarded. + * Send an ABORT, with causes if there is any. + */ + if (err_chunk) { + packet = sctp_abort_pkt_new(ep, asoc, arg, + (__u8 *)(err_chunk->chunk_hdr) + + sizeof(sctp_chunkhdr_t), + ntohs(err_chunk->chunk_hdr->length) - + sizeof(sctp_chunkhdr_t)); + + sctp_chunk_free(err_chunk); + + if (packet) { + sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, + SCTP_PACKET(packet)); + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, + SCTP_NULL()); + return SCTP_DISPOSITION_CONSUME; + } else { + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, + SCTP_NULL()); + return SCTP_DISPOSITION_NOMEM; + } + } else { + ret = sctp_sf_tabort_8_4_8(ep, asoc, type, arg, + commands); + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, + SCTP_NULL()); + return ret; + } + } + + /* Tag the variable length parameters. Note that we never + * convert the parameters in an INIT chunk. + */ + chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); + + initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; + + sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, + SCTP_PEER_INIT(initchunk)); + + /* 5.1 C) "A" shall stop the T1-init timer and leave + * COOKIE-WAIT state. "A" shall then ... start the T1-cookie + * timer, and enter the COOKIE-ECHOED state. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); + + /* 5.1 C) "A" shall then send the State Cookie received in the + * INIT ACK chunk in a COOKIE ECHO chunk, ... + */ + /* If there is any errors to report, send the ERROR chunk generated + * for unknown parameters as well. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, + SCTP_CHUNK(err_chunk)); + + return SCTP_DISPOSITION_CONSUME; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Respond to a normal COOKIE ECHO chunk. + * We are the side that is being asked for an association. + * + * Section: 5.1 Normal Establishment of an Association, D + * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply + * with a COOKIE ACK chunk after building a TCB and moving to + * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with + * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK + * chunk MUST be the first chunk in the packet. + * + * IMPLEMENTATION NOTE: An implementation may choose to send the + * Communication Up notification to the SCTP user upon reception + * of a valid COOKIE ECHO chunk. + * + * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules + * D) Rules for packet carrying a COOKIE ECHO + * + * - When sending a COOKIE ECHO, the endpoint MUST use the value of the + * Initial Tag received in the INIT ACK. + * + * - The receiver of a COOKIE ECHO follows the procedures in Section 5. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_association *new_asoc; + sctp_init_chunk_t *peer_init; + struct sctp_chunk *repl; + struct sctp_ulpevent *ev; + int error = 0; + struct sctp_chunk *err_chk_p; + + /* If the packet is an OOTB packet which is temporarily on the + * control endpoint, respond with an ABORT. + */ + if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) + return sctp_sf_ootb(ep, asoc, type, arg, commands); + + /* Make sure that the COOKIE_ECHO chunk has a valid length. + * In this case, we check that we have enough for at least a + * chunk header. More detailed verification is done + * in sctp_unpack_cookie(). + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* "Decode" the chunk. We have no optional parameters so we + * are in good shape. + */ + chunk->subh.cookie_hdr = + (struct sctp_signed_cookie *)chunk->skb->data; + skb_pull(chunk->skb, + ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t)); + + /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint + * "Z" will reply with a COOKIE ACK chunk after building a TCB + * and moving to the ESTABLISHED state. + */ + new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, + &err_chk_p); + + /* FIXME: + * If the re-build failed, what is the proper error path + * from here? + * + * [We should abort the association. --piggy] + */ + if (!new_asoc) { + /* FIXME: Several errors are possible. A bad cookie should + * be silently discarded, but think about logging it too. + */ + switch (error) { + case -SCTP_IERROR_NOMEM: + goto nomem; + + case -SCTP_IERROR_STALE_COOKIE: + sctp_send_stale_cookie_err(ep, asoc, chunk, commands, + err_chk_p); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + case -SCTP_IERROR_BAD_SIG: + default: + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + }; + } + + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_ESTABLISHED)); + SCTP_INC_STATS(SCTP_MIB_CURRESTAB); + SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS); + sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); + + if (new_asoc->autoclose) + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, + SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); + + sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); + + /* Re-build the bind address for the association is done in + * the sctp_unpack_cookie() already. + */ + /* This is a brand-new association, so these are not yet side + * effects--it is safe to run them here. + */ + peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; + + if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, + &chunk->subh.cookie_hdr->c.peer_addr, + peer_init, GFP_ATOMIC)) + goto nomem_init; + + repl = sctp_make_cookie_ack(new_asoc, chunk); + if (!repl) + goto nomem_repl; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); + + /* RFC 2960 5.1 Normal Establishment of an Association + * + * D) IMPLEMENTATION NOTE: An implementation may choose to + * send the Communication Up notification to the SCTP user + * upon reception of a valid COOKIE ECHO chunk. + */ + ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, + new_asoc->c.sinit_num_ostreams, + new_asoc->c.sinit_max_instreams, + GFP_ATOMIC); + if (!ev) + goto nomem_ev; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); + + /* Sockets API Draft Section 5.3.1.6 + * When a peer sends a Adaption Layer Indication parameter , SCTP + * delivers this notification to inform the application that of the + * peers requested adaption layer. + */ + if (new_asoc->peer.adaption_ind) { + ev = sctp_ulpevent_make_adaption_indication(new_asoc, + GFP_ATOMIC); + if (!ev) + goto nomem_ev; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, + SCTP_ULPEVENT(ev)); + } + + return SCTP_DISPOSITION_CONSUME; + +nomem_ev: + sctp_chunk_free(repl); +nomem_repl: +nomem_init: + sctp_association_free(new_asoc); +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Respond to a normal COOKIE ACK chunk. + * We are the side that is being asked for an association. + * + * RFC 2960 5.1 Normal Establishment of an Association + * + * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the + * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie + * timer. It may also notify its ULP about the successful + * establishment of the association with a Communication Up + * notification (see Section 10). + * + * Verification Tag: + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_ulpevent *ev; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Verify that the chunk length for the COOKIE-ACK is OK. + * If we don't do this, any bundled chunks may be junked. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + /* Reset init error count upon receipt of COOKIE-ACK, + * to avoid problems with the managemement of this + * counter in stale cookie situations when a transition back + * from the COOKIE-ECHOED state to the COOKIE-WAIT + * state is performed. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_COUNTER_RESET, + SCTP_COUNTER(SCTP_COUNTER_INIT_ERROR)); + + /* RFC 2960 5.1 Normal Establishment of an Association + * + * E) Upon reception of the COOKIE ACK, endpoint "A" will move + * from the COOKIE-ECHOED state to the ESTABLISHED state, + * stopping the T1-cookie timer. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_ESTABLISHED)); + SCTP_INC_STATS(SCTP_MIB_CURRESTAB); + SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS); + sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); + if (asoc->autoclose) + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, + SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); + sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); + + /* It may also notify its ULP about the successful + * establishment of the association with a Communication Up + * notification (see Section 10). + */ + ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, + 0, asoc->c.sinit_num_ostreams, + asoc->c.sinit_max_instreams, + GFP_ATOMIC); + + if (!ev) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); + + /* Sockets API Draft Section 5.3.1.6 + * When a peer sends a Adaption Layer Indication parameter , SCTP + * delivers this notification to inform the application that of the + * peers requested adaption layer. + */ + if (asoc->peer.adaption_ind) { + ev = sctp_ulpevent_make_adaption_indication(asoc, GFP_ATOMIC); + if (!ev) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, + SCTP_ULPEVENT(ev)); + } + + return SCTP_DISPOSITION_CONSUME; +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* Generate and sendout a heartbeat packet. */ +static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_transport *transport = (struct sctp_transport *) arg; + struct sctp_chunk *reply; + sctp_sender_hb_info_t hbinfo; + size_t paylen = 0; + + hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO; + hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t)); + hbinfo.daddr = transport->ipaddr; + hbinfo.sent_at = jiffies; + + /* Send a heartbeat to our peer. */ + paylen = sizeof(sctp_sender_hb_info_t); + reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen); + if (!reply) + return SCTP_DISPOSITION_NOMEM; + + /* Set rto_pending indicating that an RTT measurement + * is started with this heartbeat chunk. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, + SCTP_TRANSPORT(transport)); + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + return SCTP_DISPOSITION_CONSUME; +} + +/* Generate a HEARTBEAT packet on the given transport. */ +sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_transport *transport = (struct sctp_transport *) arg; + + if (asoc->overall_error_count > asoc->max_retrans) { + /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_NO_ERROR)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + return SCTP_DISPOSITION_DELETE_TCB; + } + + /* Section 3.3.5. + * The Sender-specific Heartbeat Info field should normally include + * information about the sender's current time when this HEARTBEAT + * chunk is sent and the destination transport address to which this + * HEARTBEAT is sent (see Section 8.3). + */ + + if (transport->hb_allowed) { + if (SCTP_DISPOSITION_NOMEM == + sctp_sf_heartbeat(ep, asoc, type, arg, + commands)) + return SCTP_DISPOSITION_NOMEM; + /* Set transport error counter and association error counter + * when sending heartbeat. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, + SCTP_TRANSPORT(transport)); + } + sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, + SCTP_TRANSPORT(transport)); + + return SCTP_DISPOSITION_CONSUME; +} + +/* + * Process an heartbeat request. + * + * Section: 8.3 Path Heartbeat + * The receiver of the HEARTBEAT should immediately respond with a + * HEARTBEAT ACK that contains the Heartbeat Information field copied + * from the received HEARTBEAT chunk. + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * When receiving an SCTP packet, the endpoint MUST ensure that the + * value in the Verification Tag field of the received SCTP packet + * matches its own Tag. If the received Verification Tag value does not + * match the receiver's own tag value, the receiver shall silently + * discard the packet and shall not process it any further except for + * those cases listed in Section 8.5.1 below. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_chunk *reply; + size_t paylen = 0; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the HEARTBEAT chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + /* 8.3 The receiver of the HEARTBEAT should immediately + * respond with a HEARTBEAT ACK that contains the Heartbeat + * Information field copied from the received HEARTBEAT chunk. + */ + chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; + paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); + skb_pull(chunk->skb, paylen); + + reply = sctp_make_heartbeat_ack(asoc, chunk, + chunk->subh.hb_hdr, paylen); + if (!reply) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + return SCTP_DISPOSITION_CONSUME; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Process the returning HEARTBEAT ACK. + * + * Section: 8.3 Path Heartbeat + * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT + * should clear the error counter of the destination transport + * address to which the HEARTBEAT was sent, and mark the destination + * transport address as active if it is not so marked. The endpoint may + * optionally report to the upper layer when an inactive destination + * address is marked as active due to the reception of the latest + * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also + * clear the association overall error count as well (as defined + * in section 8.1). + * + * The receiver of the HEARTBEAT ACK should also perform an RTT + * measurement for that destination transport address using the time + * value carried in the HEARTBEAT ACK chunk. + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + union sctp_addr from_addr; + struct sctp_transport *link; + sctp_sender_hb_info_t *hbinfo; + unsigned long max_interval; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; + from_addr = hbinfo->daddr; + link = sctp_assoc_lookup_paddr(asoc, &from_addr); + + /* This should never happen, but lets log it if so. */ + if (!link) { + printk(KERN_WARNING + "%s: Could not find address %d.%d.%d.%d\n", + __FUNCTION__, NIPQUAD(from_addr.v4.sin_addr)); + return SCTP_DISPOSITION_DISCARD; + } + + max_interval = link->hb_interval + link->rto; + + /* Check if the timestamp looks valid. */ + if (time_after(hbinfo->sent_at, jiffies) || + time_after(jiffies, hbinfo->sent_at + max_interval)) { + SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp" + "received for transport: %p\n", + __FUNCTION__, link); + return SCTP_DISPOSITION_DISCARD; + } + + /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of + * the HEARTBEAT should clear the error counter of the + * destination transport address to which the HEARTBEAT was + * sent and mark the destination transport address as active if + * it is not so marked. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); + + return SCTP_DISPOSITION_CONSUME; +} + +/* Helper function to send out an abort for the restart + * condition. + */ +static int sctp_sf_send_restart_abort(union sctp_addr *ssa, + struct sctp_chunk *init, + sctp_cmd_seq_t *commands) +{ + int len; + struct sctp_packet *pkt; + union sctp_addr_param *addrparm; + struct sctp_errhdr *errhdr; + struct sctp_endpoint *ep; + char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; + struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); + + /* Build the error on the stack. We are way to malloc crazy + * throughout the code today. + */ + errhdr = (struct sctp_errhdr *)buffer; + addrparm = (union sctp_addr_param *)errhdr->variable; + + /* Copy into a parm format. */ + len = af->to_addr_param(ssa, addrparm); + len += sizeof(sctp_errhdr_t); + + errhdr->cause = SCTP_ERROR_RESTART; + errhdr->length = htons(len); + + /* Assign to the control socket. */ + ep = sctp_sk((sctp_get_ctl_sock()))->ep; + + /* Association is NULL since this may be a restart attack and we + * want to send back the attacker's vtag. + */ + pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); + + if (!pkt) + goto out; + sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); + + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); + + /* Discard the rest of the inbound packet. */ + sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); + +out: + /* Even if there is no memory, treat as a failure so + * the packet will get dropped. + */ + return 0; +} + +/* A restart is occurring, check to make sure no new addresses + * are being added as we may be under a takeover attack. + */ +static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, + const struct sctp_association *asoc, + struct sctp_chunk *init, + sctp_cmd_seq_t *commands) +{ + struct sctp_transport *new_addr, *addr; + struct list_head *pos, *pos2; + int found; + + /* Implementor's Guide - Sectin 5.2.2 + * ... + * Before responding the endpoint MUST check to see if the + * unexpected INIT adds new addresses to the association. If new + * addresses are added to the association, the endpoint MUST respond + * with an ABORT.. + */ + + /* Search through all current addresses and make sure + * we aren't adding any new ones. + */ + new_addr = NULL; + found = 0; + + list_for_each(pos, &new_asoc->peer.transport_addr_list) { + new_addr = list_entry(pos, struct sctp_transport, transports); + found = 0; + list_for_each(pos2, &asoc->peer.transport_addr_list) { + addr = list_entry(pos2, struct sctp_transport, + transports); + if (sctp_cmp_addr_exact(&new_addr->ipaddr, + &addr->ipaddr)) { + found = 1; + break; + } + } + if (!found) + break; + } + + /* If a new address was added, ABORT the sender. */ + if (!found && new_addr) { + sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); + } + + /* Return success if all addresses were found. */ + return found; +} + +/* Populate the verification/tie tags based on overlapping INIT + * scenario. + * + * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. + */ +static void sctp_tietags_populate(struct sctp_association *new_asoc, + const struct sctp_association *asoc) +{ + switch (asoc->state) { + + /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ + + case SCTP_STATE_COOKIE_WAIT: + new_asoc->c.my_vtag = asoc->c.my_vtag; + new_asoc->c.my_ttag = asoc->c.my_vtag; + new_asoc->c.peer_ttag = 0; + break; + + case SCTP_STATE_COOKIE_ECHOED: + new_asoc->c.my_vtag = asoc->c.my_vtag; + new_asoc->c.my_ttag = asoc->c.my_vtag; + new_asoc->c.peer_ttag = asoc->c.peer_vtag; + break; + + /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, + * COOKIE-WAIT and SHUTDOWN-ACK-SENT + */ + default: + new_asoc->c.my_ttag = asoc->c.my_vtag; + new_asoc->c.peer_ttag = asoc->c.peer_vtag; + break; + }; + + /* Other parameters for the endpoint SHOULD be copied from the + * existing parameters of the association (e.g. number of + * outbound streams) into the INIT ACK and cookie. + */ + new_asoc->rwnd = asoc->rwnd; + new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; + new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; + new_asoc->c.initial_tsn = asoc->c.initial_tsn; +} + +/* + * Compare vtag/tietag values to determine unexpected COOKIE-ECHO + * handling action. + * + * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. + * + * Returns value representing action to be taken. These action values + * correspond to Action/Description values in RFC 2960, Table 2. + */ +static char sctp_tietags_compare(struct sctp_association *new_asoc, + const struct sctp_association *asoc) +{ + /* In this case, the peer may have restarted. */ + if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && + (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && + (asoc->c.my_vtag == new_asoc->c.my_ttag) && + (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) + return 'A'; + + /* Collision case B. */ + if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && + ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || + (0 == asoc->c.peer_vtag))) { + return 'B'; + } + + /* Collision case D. */ + if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && + (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) + return 'D'; + + /* Collision case C. */ + if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && + (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && + (0 == new_asoc->c.my_ttag) && + (0 == new_asoc->c.peer_ttag)) + return 'C'; + + /* No match to any of the special cases; discard this packet. */ + return 'E'; +} + +/* Common helper routine for both duplicate and simulataneous INIT + * chunk handling. + */ +static sctp_disposition_t sctp_sf_do_unexpected_init( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, sctp_cmd_seq_t *commands) +{ + sctp_disposition_t retval; + struct sctp_chunk *chunk = arg; + struct sctp_chunk *repl; + struct sctp_association *new_asoc; + struct sctp_chunk *err_chunk; + struct sctp_packet *packet; + sctp_unrecognized_param_t *unk_param; + int len; + + /* 6.10 Bundling + * An endpoint MUST NOT bundle INIT, INIT ACK or + * SHUTDOWN COMPLETE with any other chunks. + * + * IG Section 2.11.2 + * Furthermore, we require that the receiver of an INIT chunk MUST + * enforce these rules by silently discarding an arriving packet + * with an INIT chunk that is bundled with other chunks. + */ + if (!chunk->singleton) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* 3.1 A packet containing an INIT chunk MUST have a zero Verification + * Tag. + */ + if (chunk->sctp_hdr->vtag != 0) + return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); + + /* Make sure that the INIT chunk has a valid length. + * In this case, we generate a protocol violation since we have + * an association established. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + /* Grab the INIT header. */ + chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; + + /* Tag the variable length parameters. */ + chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); + + /* Verify the INIT chunk before processing it. */ + err_chunk = NULL; + if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, + (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, + &err_chunk)) { + /* This chunk contains fatal error. It is to be discarded. + * Send an ABORT, with causes if there is any. + */ + if (err_chunk) { + packet = sctp_abort_pkt_new(ep, asoc, arg, + (__u8 *)(err_chunk->chunk_hdr) + + sizeof(sctp_chunkhdr_t), + ntohs(err_chunk->chunk_hdr->length) - + sizeof(sctp_chunkhdr_t)); + + if (packet) { + sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, + SCTP_PACKET(packet)); + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); + retval = SCTP_DISPOSITION_CONSUME; + } else { + retval = SCTP_DISPOSITION_NOMEM; + } + goto cleanup; + } else { + return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, + commands); + } + } + + /* + * Other parameters for the endpoint SHOULD be copied from the + * existing parameters of the association (e.g. number of + * outbound streams) into the INIT ACK and cookie. + * FIXME: We are copying parameters from the endpoint not the + * association. + */ + new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); + if (!new_asoc) + goto nomem; + + /* In the outbound INIT ACK the endpoint MUST copy its current + * Verification Tag and Peers Verification tag into a reserved + * place (local tie-tag and per tie-tag) within the state cookie. + */ + if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, + sctp_source(chunk), + (sctp_init_chunk_t *)chunk->chunk_hdr, + GFP_ATOMIC)) { + retval = SCTP_DISPOSITION_NOMEM; + goto nomem_init; + } + + /* Make sure no new addresses are being added during the + * restart. Do not do this check for COOKIE-WAIT state, + * since there are no peer addresses to check against. + * Upon return an ABORT will have been sent if needed. + */ + if (!sctp_state(asoc, COOKIE_WAIT)) { + if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, + commands)) { + retval = SCTP_DISPOSITION_CONSUME; + goto cleanup_asoc; + } + } + + sctp_tietags_populate(new_asoc, asoc); + + /* B) "Z" shall respond immediately with an INIT ACK chunk. */ + + /* If there are errors need to be reported for unknown parameters, + * make sure to reserve enough room in the INIT ACK for them. + */ + len = 0; + if (err_chunk) { + len = ntohs(err_chunk->chunk_hdr->length) - + sizeof(sctp_chunkhdr_t); + } + + if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) + goto nomem; + + repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); + if (!repl) + goto nomem; + + /* If there are errors need to be reported for unknown parameters, + * include them in the outgoing INIT ACK as "Unrecognized parameter" + * parameter. + */ + if (err_chunk) { + /* Get the "Unrecognized parameter" parameter(s) out of the + * ERROR chunk generated by sctp_verify_init(). Since the + * error cause code for "unknown parameter" and the + * "Unrecognized parameter" type is the same, we can + * construct the parameters in INIT ACK by copying the + * ERROR causes over. + */ + unk_param = (sctp_unrecognized_param_t *) + ((__u8 *)(err_chunk->chunk_hdr) + + sizeof(sctp_chunkhdr_t)); + /* Replace the cause code with the "Unrecognized parameter" + * parameter type. + */ + sctp_addto_chunk(repl, len, unk_param); + } + + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); + + /* + * Note: After sending out INIT ACK with the State Cookie parameter, + * "Z" MUST NOT allocate any resources for this new association. + * Otherwise, "Z" will be vulnerable to resource attacks. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); + retval = SCTP_DISPOSITION_CONSUME; + +cleanup: + if (err_chunk) + sctp_chunk_free(err_chunk); + return retval; +nomem: + retval = SCTP_DISPOSITION_NOMEM; + goto cleanup; +nomem_init: +cleanup_asoc: + sctp_association_free(new_asoc); + goto cleanup; +} + +/* + * Handle simultanous INIT. + * This means we started an INIT and then we got an INIT request from + * our peer. + * + * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) + * This usually indicates an initialization collision, i.e., each + * endpoint is attempting, at about the same time, to establish an + * association with the other endpoint. + * + * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an + * endpoint MUST respond with an INIT ACK using the same parameters it + * sent in its original INIT chunk (including its Verification Tag, + * unchanged). These original parameters are combined with those from the + * newly received INIT chunk. The endpoint shall also generate a State + * Cookie with the INIT ACK. The endpoint uses the parameters sent in its + * INIT to calculate the State Cookie. + * + * After that, the endpoint MUST NOT change its state, the T1-init + * timer shall be left running and the corresponding TCB MUST NOT be + * destroyed. The normal procedures for handling State Cookies when + * a TCB exists will resolve the duplicate INITs to a single association. + * + * For an endpoint that is in the COOKIE-ECHOED state it MUST populate + * its Tie-Tags with the Tag information of itself and its peer (see + * section 5.2.2 for a description of the Tie-Tags). + * + * Verification Tag: Not explicit, but an INIT can not have a valid + * verification tag, so we skip the check. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* Call helper to do the real work for both simulataneous and + * duplicate INIT chunk handling. + */ + return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); +} + +/* + * Handle duplicated INIT messages. These are usually delayed + * restransmissions. + * + * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, + * COOKIE-ECHOED and COOKIE-WAIT + * + * Unless otherwise stated, upon reception of an unexpected INIT for + * this association, the endpoint shall generate an INIT ACK with a + * State Cookie. In the outbound INIT ACK the endpoint MUST copy its + * current Verification Tag and peer's Verification Tag into a reserved + * place within the state cookie. We shall refer to these locations as + * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet + * containing this INIT ACK MUST carry a Verification Tag value equal to + * the Initiation Tag found in the unexpected INIT. And the INIT ACK + * MUST contain a new Initiation Tag (randomly generated see Section + * 5.3.1). Other parameters for the endpoint SHOULD be copied from the + * existing parameters of the association (e.g. number of outbound + * streams) into the INIT ACK and cookie. + * + * After sending out the INIT ACK, the endpoint shall take no further + * actions, i.e., the existing association, including its current state, + * and the corresponding TCB MUST NOT be changed. + * + * Note: Only when a TCB exists and the association is not in a COOKIE- + * WAIT state are the Tie-Tags populated. For a normal association INIT + * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be + * set to 0 (indicating that no previous TCB existed). The INIT ACK and + * State Cookie are populated as specified in section 5.2.1. + * + * Verification Tag: Not specified, but an INIT has no way of knowing + * what the verification tag could be, so we ignore it. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* Call helper to do the real work for both simulataneous and + * duplicate INIT chunk handling. + */ + return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); +} + + + +/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') + * + * Section 5.2.4 + * A) In this case, the peer may have restarted. + */ +static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + struct sctp_chunk *chunk, + sctp_cmd_seq_t *commands, + struct sctp_association *new_asoc) +{ + sctp_init_chunk_t *peer_init; + struct sctp_ulpevent *ev; + struct sctp_chunk *repl; + struct sctp_chunk *err; + sctp_disposition_t disposition; + + /* new_asoc is a brand-new association, so these are not yet + * side effects--it is safe to run them here. + */ + peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; + + if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, + sctp_source(chunk), peer_init, + GFP_ATOMIC)) + goto nomem; + + /* Make sure no new addresses are being added during the + * restart. Though this is a pretty complicated attack + * since you'd have to get inside the cookie. + */ + if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { + return SCTP_DISPOSITION_CONSUME; + } + + /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes + * the peer has restarted (Action A), it MUST NOT setup a new + * association but instead resend the SHUTDOWN ACK and send an ERROR + * chunk with a "Cookie Received while Shutting Down" error cause to + * its peer. + */ + if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { + disposition = sctp_sf_do_9_2_reshutack(ep, asoc, + SCTP_ST_CHUNK(chunk->chunk_hdr->type), + chunk, commands); + if (SCTP_DISPOSITION_NOMEM == disposition) + goto nomem; + + err = sctp_make_op_error(asoc, chunk, + SCTP_ERROR_COOKIE_IN_SHUTDOWN, + NULL, 0); + if (err) + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(err)); + + return SCTP_DISPOSITION_CONSUME; + } + + /* For now, fail any unsent/unacked data. Consider the optional + * choice of resending of this data. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); + + /* Update the content of current association. */ + sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); + + repl = sctp_make_cookie_ack(new_asoc, chunk); + if (!repl) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); + + /* Report association restart to upper layer. */ + ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, + new_asoc->c.sinit_num_ostreams, + new_asoc->c.sinit_max_instreams, + GFP_ATOMIC); + if (!ev) + goto nomem_ev; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); + return SCTP_DISPOSITION_CONSUME; + +nomem_ev: + sctp_chunk_free(repl); +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') + * + * Section 5.2.4 + * B) In this case, both sides may be attempting to start an association + * at about the same time but the peer endpoint started its INIT + * after responding to the local endpoint's INIT + */ +/* This case represents an initialization collision. */ +static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + struct sctp_chunk *chunk, + sctp_cmd_seq_t *commands, + struct sctp_association *new_asoc) +{ + sctp_init_chunk_t *peer_init; + struct sctp_ulpevent *ev; + struct sctp_chunk *repl; + + /* new_asoc is a brand-new association, so these are not yet + * side effects--it is safe to run them here. + */ + peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; + if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, + sctp_source(chunk), peer_init, + GFP_ATOMIC)) + goto nomem; + + /* Update the content of current association. */ + sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_ESTABLISHED)); + SCTP_INC_STATS(SCTP_MIB_CURRESTAB); + sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); + + repl = sctp_make_cookie_ack(new_asoc, chunk); + if (!repl) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); + sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); + + /* RFC 2960 5.1 Normal Establishment of an Association + * + * D) IMPLEMENTATION NOTE: An implementation may choose to + * send the Communication Up notification to the SCTP user + * upon reception of a valid COOKIE ECHO chunk. + */ + ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 0, + new_asoc->c.sinit_num_ostreams, + new_asoc->c.sinit_max_instreams, + GFP_ATOMIC); + if (!ev) + goto nomem_ev; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); + + /* Sockets API Draft Section 5.3.1.6 + * When a peer sends a Adaption Layer Indication parameter , SCTP + * delivers this notification to inform the application that of the + * peers requested adaption layer. + */ + if (asoc->peer.adaption_ind) { + ev = sctp_ulpevent_make_adaption_indication(asoc, GFP_ATOMIC); + if (!ev) + goto nomem_ev; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, + SCTP_ULPEVENT(ev)); + } + + return SCTP_DISPOSITION_CONSUME; + +nomem_ev: + sctp_chunk_free(repl); +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') + * + * Section 5.2.4 + * C) In this case, the local endpoint's cookie has arrived late. + * Before it arrived, the local endpoint sent an INIT and received an + * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag + * but a new tag of its own. + */ +/* This case represents an initialization collision. */ +static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + struct sctp_chunk *chunk, + sctp_cmd_seq_t *commands, + struct sctp_association *new_asoc) +{ + /* The cookie should be silently discarded. + * The endpoint SHOULD NOT change states and should leave + * any timers running. + */ + return SCTP_DISPOSITION_DISCARD; +} + +/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') + * + * Section 5.2.4 + * + * D) When both local and remote tags match the endpoint should always + * enter the ESTABLISHED state, if it has not already done so. + */ +/* This case represents an initialization collision. */ +static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + struct sctp_chunk *chunk, + sctp_cmd_seq_t *commands, + struct sctp_association *new_asoc) +{ + struct sctp_ulpevent *ev = NULL; + struct sctp_chunk *repl; + + /* Clarification from Implementor's Guide: + * D) When both local and remote tags match the endpoint should + * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. + * It should stop any cookie timer that may be running and send + * a COOKIE ACK. + */ + + /* Don't accidentally move back into established state. */ + if (asoc->state < SCTP_STATE_ESTABLISHED) { + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_ESTABLISHED)); + SCTP_INC_STATS(SCTP_MIB_CURRESTAB); + sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, + SCTP_NULL()); + + /* RFC 2960 5.1 Normal Establishment of an Association + * + * D) IMPLEMENTATION NOTE: An implementation may choose + * to send the Communication Up notification to the + * SCTP user upon reception of a valid COOKIE + * ECHO chunk. + */ + ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, + SCTP_COMM_UP, 0, + new_asoc->c.sinit_num_ostreams, + new_asoc->c.sinit_max_instreams, + GFP_ATOMIC); + if (!ev) + goto nomem; + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, + SCTP_ULPEVENT(ev)); + + /* Sockets API Draft Section 5.3.1.6 + * When a peer sends a Adaption Layer Indication parameter, + * SCTP delivers this notification to inform the application + * that of the peers requested adaption layer. + */ + if (new_asoc->peer.adaption_ind) { + ev = sctp_ulpevent_make_adaption_indication(new_asoc, + GFP_ATOMIC); + if (!ev) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, + SCTP_ULPEVENT(ev)); + } + } + sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); + + repl = sctp_make_cookie_ack(new_asoc, chunk); + if (!repl) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); + sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); + + return SCTP_DISPOSITION_CONSUME; + +nomem: + if (ev) + sctp_ulpevent_free(ev); + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying + * chunk was retransmitted and then delayed in the network. + * + * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists + * + * Verification Tag: None. Do cookie validation. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + sctp_disposition_t retval; + struct sctp_chunk *chunk = arg; + struct sctp_association *new_asoc; + int error = 0; + char action; + struct sctp_chunk *err_chk_p; + + /* Make sure that the chunk has a valid length from the protocol + * perspective. In this case check to make sure we have at least + * enough for the chunk header. Cookie length verification is + * done later. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + /* "Decode" the chunk. We have no optional parameters so we + * are in good shape. + */ + chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; + skb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - + sizeof(sctp_chunkhdr_t)); + + /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie + * of a duplicate COOKIE ECHO match the Verification Tags of the + * current association, consider the State Cookie valid even if + * the lifespan is exceeded. + */ + new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, + &err_chk_p); + + /* FIXME: + * If the re-build failed, what is the proper error path + * from here? + * + * [We should abort the association. --piggy] + */ + if (!new_asoc) { + /* FIXME: Several errors are possible. A bad cookie should + * be silently discarded, but think about logging it too. + */ + switch (error) { + case -SCTP_IERROR_NOMEM: + goto nomem; + + case -SCTP_IERROR_STALE_COOKIE: + sctp_send_stale_cookie_err(ep, asoc, chunk, commands, + err_chk_p); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + case -SCTP_IERROR_BAD_SIG: + default: + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + }; + } + + /* Compare the tie_tag in cookie with the verification tag of + * current association. + */ + action = sctp_tietags_compare(new_asoc, asoc); + + switch (action) { + case 'A': /* Association restart. */ + retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, + new_asoc); + break; + + case 'B': /* Collision case B. */ + retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, + new_asoc); + break; + + case 'C': /* Collision case C. */ + retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, + new_asoc); + break; + + case 'D': /* Collision case D. */ + retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, + new_asoc); + break; + + default: /* Discard packet for all others. */ + retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); + break; + }; + + /* Delete the tempory new association. */ + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); + + return retval; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Process an ABORT. (SHUTDOWN-PENDING state) + * + * See sctp_sf_do_9_1_abort(). + */ +sctp_disposition_t sctp_sf_shutdown_pending_abort( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + + if (!sctp_vtag_verify_either(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the ABORT chunk has a valid length. + * Since this is an ABORT chunk, we have to discard it + * because of the following text: + * RFC 2960, Section 3.3.7 + * If an endpoint receives an ABORT with a format error or for an + * association that doesn't exist, it MUST silently discard it. + * Becasue the length is "invalid", we can't really discard just + * as we do not know its true length. So, to be safe, discard the + * packet. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Stop the T5-shutdown guard timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); + + return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); +} + +/* + * Process an ABORT. (SHUTDOWN-SENT state) + * + * See sctp_sf_do_9_1_abort(). + */ +sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + + if (!sctp_vtag_verify_either(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the ABORT chunk has a valid length. + * Since this is an ABORT chunk, we have to discard it + * because of the following text: + * RFC 2960, Section 3.3.7 + * If an endpoint receives an ABORT with a format error or for an + * association that doesn't exist, it MUST silently discard it. + * Becasue the length is "invalid", we can't really discard just + * as we do not know its true length. So, to be safe, discard the + * packet. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Stop the T2-shutdown timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + + /* Stop the T5-shutdown guard timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); + + return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); +} + +/* + * Process an ABORT. (SHUTDOWN-ACK-SENT state) + * + * See sctp_sf_do_9_1_abort(). + */ +sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* The same T2 timer, so we should be able to use + * common function with the SHUTDOWN-SENT state. + */ + return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); +} + +/* + * Handle an Error received in COOKIE_ECHOED state. + * + * Only handle the error type of stale COOKIE Error, the other errors will + * be ignored. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + sctp_errhdr_t *err; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the ERROR chunk has a valid length. + * The parameter walking depends on this as well. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + /* Process the error here */ + /* FUTURE FIXME: When PR-SCTP related and other optional + * parms are emitted, this will have to change to handle multiple + * errors. + */ + sctp_walk_errors(err, chunk->chunk_hdr) { + if (SCTP_ERROR_STALE_COOKIE == err->cause) + return sctp_sf_do_5_2_6_stale(ep, asoc, type, + arg, commands); + } + + /* It is possible to have malformed error causes, and that + * will cause us to end the walk early. However, since + * we are discarding the packet, there should be no adverse + * affects. + */ + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); +} + +/* + * Handle a Stale COOKIE Error + * + * Section: 5.2.6 Handle Stale COOKIE Error + * If the association is in the COOKIE-ECHOED state, the endpoint may elect + * one of the following three alternatives. + * ... + * 3) Send a new INIT chunk to the endpoint, adding a Cookie + * Preservative parameter requesting an extension to the lifetime of + * the State Cookie. When calculating the time extension, an + * implementation SHOULD use the RTT information measured based on the + * previous COOKIE ECHO / ERROR exchange, and should add no more + * than 1 second beyond the measured RTT, due to long State Cookie + * lifetimes making the endpoint more subject to a replay attack. + * + * Verification Tag: Not explicit, but safe to ignore. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + time_t stale; + sctp_cookie_preserve_param_t bht; + sctp_errhdr_t *err; + struct sctp_chunk *reply; + struct sctp_bind_addr *bp; + int attempts; + + attempts = asoc->counters[SCTP_COUNTER_INIT_ERROR] + 1; + + if (attempts >= asoc->max_init_attempts) { + sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, + SCTP_U32(SCTP_ERROR_STALE_COOKIE)); + return SCTP_DISPOSITION_DELETE_TCB; + } + + err = (sctp_errhdr_t *)(chunk->skb->data); + + /* When calculating the time extension, an implementation + * SHOULD use the RTT information measured based on the + * previous COOKIE ECHO / ERROR exchange, and should add no + * more than 1 second beyond the measured RTT, due to long + * State Cookie lifetimes making the endpoint more subject to + * a replay attack. + * Measure of Staleness's unit is usec. (1/1000000 sec) + * Suggested Cookie Life-span Increment's unit is msec. + * (1/1000 sec) + * In general, if you use the suggested cookie life, the value + * found in the field of measure of staleness should be doubled + * to give ample time to retransmit the new cookie and thus + * yield a higher probability of success on the reattempt. + */ + stale = ntohl(*(suseconds_t *)((u8 *)err + sizeof(sctp_errhdr_t))); + stale = (stale * 2) / 1000; + + bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; + bht.param_hdr.length = htons(sizeof(bht)); + bht.lifespan_increment = htonl(stale); + + /* Build that new INIT chunk. */ + bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; + reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); + if (!reply) + goto nomem; + + sctp_addto_chunk(reply, sizeof(bht), &bht); + + /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ + sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); + + /* Stop pending T3-rtx and heartbeat timers */ + sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); + sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); + + /* Delete non-primary peer ip addresses since we are transitioning + * back to the COOKIE-WAIT state + */ + sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); + + /* If we've sent any data bundled with COOKIE-ECHO we will need to + * resend + */ + sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, + SCTP_TRANSPORT(asoc->peer.primary_path)); + + /* Cast away the const modifier, as we want to just + * rerun it through as a sideffect. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_COUNTER_INC, + SCTP_COUNTER(SCTP_COUNTER_INIT_ERROR)); + + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + + return SCTP_DISPOSITION_CONSUME; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Process an ABORT. + * + * Section: 9.1 + * After checking the Verification Tag, the receiving endpoint shall + * remove the association from its record, and shall report the + * termination to its upper layer. + * + * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules + * B) Rules for packet carrying ABORT: + * + * - The endpoint shall always fill in the Verification Tag field of the + * outbound packet with the destination endpoint's tag value if it + * is known. + * + * - If the ABORT is sent in response to an OOTB packet, the endpoint + * MUST follow the procedure described in Section 8.4. + * + * - The receiver MUST accept the packet if the Verification Tag + * matches either its own tag, OR the tag of its peer. Otherwise, the + * receiver MUST silently discard the packet and take no further + * action. + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + unsigned len; + __u16 error = SCTP_ERROR_NO_ERROR; + + if (!sctp_vtag_verify_either(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the ABORT chunk has a valid length. + * Since this is an ABORT chunk, we have to discard it + * because of the following text: + * RFC 2960, Section 3.3.7 + * If an endpoint receives an ABORT with a format error or for an + * association that doesn't exist, it MUST silently discard it. + * Becasue the length is "invalid", we can't really discard just + * as we do not know its true length. So, to be safe, discard the + * packet. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* See if we have an error cause code in the chunk. */ + len = ntohs(chunk->chunk_hdr->length); + if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) + error = ((sctp_errhdr_t *)chunk->skb->data)->cause; + + /* ASSOC_FAILED will DELETE_TCB. */ + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(error)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + + return SCTP_DISPOSITION_ABORT; +} + +/* + * Process an ABORT. (COOKIE-WAIT state) + * + * See sctp_sf_do_9_1_abort() above. + */ +sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + unsigned len; + __u16 error = SCTP_ERROR_NO_ERROR; + + if (!sctp_vtag_verify_either(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the ABORT chunk has a valid length. + * Since this is an ABORT chunk, we have to discard it + * because of the following text: + * RFC 2960, Section 3.3.7 + * If an endpoint receives an ABORT with a format error or for an + * association that doesn't exist, it MUST silently discard it. + * Becasue the length is "invalid", we can't really discard just + * as we do not know its true length. So, to be safe, discard the + * packet. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* See if we have an error cause code in the chunk. */ + len = ntohs(chunk->chunk_hdr->length); + if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) + error = ((sctp_errhdr_t *)chunk->skb->data)->cause; + + sctp_stop_t1_and_abort(commands, error); + return SCTP_DISPOSITION_ABORT; +} + +/* + * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) + */ +sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR); + return SCTP_DISPOSITION_ABORT; +} + +/* + * Process an ABORT. (COOKIE-ECHOED state) + */ +sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* There is a single T1 timer, so we should be able to use + * common function with the COOKIE-WAIT state. + */ + return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); +} + +/* + * Stop T1 timer and abort association with "INIT failed". + * + * This is common code called by several sctp_sf_*_abort() functions above. + */ +void sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, __u16 error) +{ + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); + /* CMD_INIT_FAILED will DELETE_TCB. */ + sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, + SCTP_U32(error)); +} + +/* + * sctp_sf_do_9_2_shut + * + * Section: 9.2 + * Upon the reception of the SHUTDOWN, the peer endpoint shall + * - enter the SHUTDOWN-RECEIVED state, + * + * - stop accepting new data from its SCTP user + * + * - verify, by checking the Cumulative TSN Ack field of the chunk, + * that all its outstanding DATA chunks have been received by the + * SHUTDOWN sender. + * + * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT + * send a SHUTDOWN in response to a ULP request. And should discard + * subsequent SHUTDOWN chunks. + * + * If there are still outstanding DATA chunks left, the SHUTDOWN + * receiver shall continue to follow normal data transmission + * procedures defined in Section 6 until all outstanding DATA chunks + * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept + * new data from its SCTP user. + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + sctp_shutdownhdr_t *sdh; + sctp_disposition_t disposition; + struct sctp_ulpevent *ev; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the SHUTDOWN chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, + sizeof(struct sctp_shutdown_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + /* Convert the elaborate header. */ + sdh = (sctp_shutdownhdr_t *)chunk->skb->data; + skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); + chunk->subh.shutdown_hdr = sdh; + + /* Upon the reception of the SHUTDOWN, the peer endpoint shall + * - enter the SHUTDOWN-RECEIVED state, + * - stop accepting new data from its SCTP user + * + * [This is implicit in the new state.] + */ + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); + disposition = SCTP_DISPOSITION_CONSUME; + + if (sctp_outq_is_empty(&asoc->outqueue)) { + disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, + arg, commands); + } + + if (SCTP_DISPOSITION_NOMEM == disposition) + goto out; + + /* - verify, by checking the Cumulative TSN Ack field of the + * chunk, that all its outstanding DATA chunks have been + * received by the SHUTDOWN sender. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, + SCTP_U32(chunk->subh.shutdown_hdr->cum_tsn_ack)); + + /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT + * When a peer sends a SHUTDOWN, SCTP delivers this notification to + * inform the application that it should cease sending data. + */ + ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); + if (!ev) { + disposition = SCTP_DISPOSITION_NOMEM; + goto out; + } + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); + +out: + return disposition; +} + +/* RFC 2960 9.2 + * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk + * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination + * transport addresses (either in the IP addresses or in the INIT chunk) + * that belong to this association, it should discard the INIT chunk and + * retransmit the SHUTDOWN ACK chunk. + */ +sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = (struct sctp_chunk *) arg; + struct sctp_chunk *reply; + + /* Since we are not going to really process this INIT, there + * is no point in verifying chunk boundries. Just generate + * the SHUTDOWN ACK. + */ + reply = sctp_make_shutdown_ack(asoc, chunk); + if (NULL == reply) + goto nomem; + + /* Set the transport for the SHUTDOWN ACK chunk and the timeout for + * the T2-SHUTDOWN timer. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); + + /* and restart the T2-shutdown timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + + return SCTP_DISPOSITION_CONSUME; +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * sctp_sf_do_ecn_cwr + * + * Section: Appendix A: Explicit Congestion Notification + * + * CWR: + * + * RFC 2481 details a specific bit for a sender to send in the header of + * its next outbound TCP segment to indicate to its peer that it has + * reduced its congestion window. This is termed the CWR bit. For + * SCTP the same indication is made by including the CWR chunk. + * This chunk contains one data element, i.e. the TSN number that + * was sent in the ECNE chunk. This element represents the lowest + * TSN number in the datagram that was originally marked with the + * CE bit. + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + sctp_cwrhdr_t *cwr; + struct sctp_chunk *chunk = arg; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + cwr = (sctp_cwrhdr_t *) chunk->skb->data; + skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); + + cwr->lowest_tsn = ntohl(cwr->lowest_tsn); + + /* Does this CWR ack the last sent congestion notification? */ + if (TSN_lte(asoc->last_ecne_tsn, cwr->lowest_tsn)) { + /* Stop sending ECNE. */ + sctp_add_cmd_sf(commands, + SCTP_CMD_ECN_CWR, + SCTP_U32(cwr->lowest_tsn)); + } + return SCTP_DISPOSITION_CONSUME; +} + +/* + * sctp_sf_do_ecne + * + * Section: Appendix A: Explicit Congestion Notification + * + * ECN-Echo + * + * RFC 2481 details a specific bit for a receiver to send back in its + * TCP acknowledgements to notify the sender of the Congestion + * Experienced (CE) bit having arrived from the network. For SCTP this + * same indication is made by including the ECNE chunk. This chunk + * contains one data element, i.e. the lowest TSN associated with the IP + * datagram marked with the CE bit..... + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + sctp_ecnehdr_t *ecne; + struct sctp_chunk *chunk = arg; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + ecne = (sctp_ecnehdr_t *) chunk->skb->data; + skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); + + /* If this is a newer ECNE than the last CWR packet we sent out */ + sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, + SCTP_U32(ntohl(ecne->lowest_tsn))); + + return SCTP_DISPOSITION_CONSUME; +} + +/* + * Section: 6.2 Acknowledgement on Reception of DATA Chunks + * + * The SCTP endpoint MUST always acknowledge the reception of each valid + * DATA chunk. + * + * The guidelines on delayed acknowledgement algorithm specified in + * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an + * acknowledgement SHOULD be generated for at least every second packet + * (not every second DATA chunk) received, and SHOULD be generated within + * 200 ms of the arrival of any unacknowledged DATA chunk. In some + * situations it may be beneficial for an SCTP transmitter to be more + * conservative than the algorithms detailed in this document allow. + * However, an SCTP transmitter MUST NOT be more aggressive than the + * following algorithms allow. + * + * A SCTP receiver MUST NOT generate more than one SACK for every + * incoming packet, other than to update the offered window as the + * receiving application consumes new data. + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + int error; + + if (!sctp_vtag_verify(chunk, asoc)) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, + SCTP_NULL()); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + } + + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + error = sctp_eat_data(asoc, chunk, commands ); + switch (error) { + case SCTP_IERROR_NO_ERROR: + break; + case SCTP_IERROR_HIGH_TSN: + case SCTP_IERROR_BAD_STREAM: + goto discard_noforce; + case SCTP_IERROR_DUP_TSN: + case SCTP_IERROR_IGNORE_TSN: + goto discard_force; + case SCTP_IERROR_NO_DATA: + goto consume; + default: + BUG(); + } + + if (asoc->autoclose) { + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); + } + + /* If this is the last chunk in a packet, we need to count it + * toward sack generation. Note that we need to SACK every + * OTHER packet containing data chunks, EVEN IF WE DISCARD + * THEM. We elect to NOT generate SACK's if the chunk fails + * the verification tag test. + * + * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks + * + * The SCTP endpoint MUST always acknowledge the reception of + * each valid DATA chunk. + * + * The guidelines on delayed acknowledgement algorithm + * specified in Section 4.2 of [RFC2581] SHOULD be followed. + * Specifically, an acknowledgement SHOULD be generated for at + * least every second packet (not every second DATA chunk) + * received, and SHOULD be generated within 200 ms of the + * arrival of any unacknowledged DATA chunk. In some + * situations it may be beneficial for an SCTP transmitter to + * be more conservative than the algorithms detailed in this + * document allow. However, an SCTP transmitter MUST NOT be + * more aggressive than the following algorithms allow. + */ + if (chunk->end_of_packet) { + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); + + /* Start the SACK timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); + } + + return SCTP_DISPOSITION_CONSUME; + +discard_force: + /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks + * + * When a packet arrives with duplicate DATA chunk(s) and with + * no new DATA chunk(s), the endpoint MUST immediately send a + * SACK with no delay. If a packet arrives with duplicate + * DATA chunk(s) bundled with new DATA chunks, the endpoint + * MAY immediately send a SACK. Normally receipt of duplicate + * DATA chunks will occur when the original SACK chunk was lost + * and the peer's RTO has expired. The duplicate TSN number(s) + * SHOULD be reported in the SACK as duplicate. + */ + /* In our case, we split the MAY SACK advice up whether or not + * the last chunk is a duplicate.' + */ + if (chunk->end_of_packet) + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); + return SCTP_DISPOSITION_DISCARD; + +discard_noforce: + if (chunk->end_of_packet) { + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); + + /* Start the SACK timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); + } + return SCTP_DISPOSITION_DISCARD; +consume: + return SCTP_DISPOSITION_CONSUME; + +} + +/* + * sctp_sf_eat_data_fast_4_4 + * + * Section: 4 (4) + * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received + * DATA chunks without delay. + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + int error; + + if (!sctp_vtag_verify(chunk, asoc)) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, + SCTP_NULL()); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + } + + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + error = sctp_eat_data(asoc, chunk, commands ); + switch (error) { + case SCTP_IERROR_NO_ERROR: + case SCTP_IERROR_HIGH_TSN: + case SCTP_IERROR_DUP_TSN: + case SCTP_IERROR_IGNORE_TSN: + case SCTP_IERROR_BAD_STREAM: + break; + case SCTP_IERROR_NO_DATA: + goto consume; + default: + BUG(); + } + + /* Go a head and force a SACK, since we are shutting down. */ + + /* Implementor's Guide. + * + * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately + * respond to each received packet containing one or more DATA chunk(s) + * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer + */ + if (chunk->end_of_packet) { + /* We must delay the chunk creation since the cumulative + * TSN has not been updated yet. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + } + +consume: + return SCTP_DISPOSITION_CONSUME; +} + +/* + * Section: 6.2 Processing a Received SACK + * D) Any time a SACK arrives, the endpoint performs the following: + * + * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, + * then drop the SACK. Since Cumulative TSN Ack is monotonically + * increasing, a SACK whose Cumulative TSN Ack is less than the + * Cumulative TSN Ack Point indicates an out-of-order SACK. + * + * ii) Set rwnd equal to the newly received a_rwnd minus the number + * of bytes still outstanding after processing the Cumulative TSN Ack + * and the Gap Ack Blocks. + * + * iii) If the SACK is missing a TSN that was previously + * acknowledged via a Gap Ack Block (e.g., the data receiver + * reneged on the data), then mark the corresponding DATA chunk + * as available for retransmit: Mark it as missing for fast + * retransmit as described in Section 7.2.4 and if no retransmit + * timer is running for the destination address to which the DATA + * chunk was originally transmitted, then T3-rtx is started for + * that destination address. + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + sctp_sackhdr_t *sackh; + __u32 ctsn; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the SACK chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + /* Pull the SACK chunk from the data buffer */ + sackh = sctp_sm_pull_sack(chunk); + /* Was this a bogus SACK? */ + if (!sackh) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + chunk->subh.sack_hdr = sackh; + ctsn = ntohl(sackh->cum_tsn_ack); + + /* i) If Cumulative TSN Ack is less than the Cumulative TSN + * Ack Point, then drop the SACK. Since Cumulative TSN + * Ack is monotonically increasing, a SACK whose + * Cumulative TSN Ack is less than the Cumulative TSN Ack + * Point indicates an out-of-order SACK. + */ + if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { + SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); + SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); + return SCTP_DISPOSITION_DISCARD; + } + + /* Return this SACK for further processing. */ + sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); + + /* Note: We do the rest of the work on the PROCESS_SACK + * sideeffect. + */ + return SCTP_DISPOSITION_CONSUME; +} + +/* + * Generate an ABORT in response to a packet. + * + * Section: 8.4 Handle "Out of the blue" Packets + * + * 8) The receiver should respond to the sender of the OOTB packet + * with an ABORT. When sending the ABORT, the receiver of the + * OOTB packet MUST fill in the Verification Tag field of the + * outbound packet with the value found in the Verification Tag + * field of the OOTB packet and set the T-bit in the Chunk Flags + * to indicate that no TCB was found. After sending this ABORT, + * the receiver of the OOTB packet shall discard the OOTB packet + * and take no further action. + * + * Verification Tag: + * + * The return value is the disposition of the chunk. +*/ +sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_packet *packet = NULL; + struct sctp_chunk *chunk = arg; + struct sctp_chunk *abort; + + packet = sctp_ootb_pkt_new(asoc, chunk); + + if (packet) { + /* Make an ABORT. The T bit will be set if the asoc + * is NULL. + */ + abort = sctp_make_abort(asoc, chunk, 0); + if (!abort) { + sctp_ootb_pkt_free(packet); + return SCTP_DISPOSITION_NOMEM; + } + + /* Set the skb to the belonging sock for accounting. */ + abort->skb->sk = ep->base.sk; + + sctp_packet_append_chunk(packet, abort); + + sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, + SCTP_PACKET(packet)); + + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); + + return SCTP_DISPOSITION_CONSUME; + } + + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR + * event as ULP notification for each cause included in the chunk. + * + * API 5.3.1.3 - SCTP_REMOTE_ERROR + * + * The return value is the disposition of the chunk. +*/ +sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_ulpevent *ev; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the ERROR chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + while (chunk->chunk_end > chunk->skb->data) { + ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, + GFP_ATOMIC); + if (!ev) + goto nomem; + + if (!sctp_add_cmd(commands, SCTP_CMD_EVENT_ULP, + SCTP_ULPEVENT(ev))) { + sctp_ulpevent_free(ev); + goto nomem; + } + + sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, + SCTP_CHUNK(chunk)); + } + return SCTP_DISPOSITION_CONSUME; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Process an inbound SHUTDOWN ACK. + * + * From Section 9.2: + * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall + * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its + * peer, and remove all record of the association. + * + * The return value is the disposition. + */ +sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_chunk *reply; + struct sctp_ulpevent *ev; + + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + /* 10.2 H) SHUTDOWN COMPLETE notification + * + * When SCTP completes the shutdown procedures (section 9.2) this + * notification is passed to the upper layer. + */ + ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, + 0, 0, 0, GFP_ATOMIC); + if (!ev) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); + + /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall + * stop the T2-shutdown timer, + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); + + /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ + reply = sctp_make_shutdown_complete(asoc, chunk); + if (!reply) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + + /* ...and remove all record of the association. */ + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); + return SCTP_DISPOSITION_DELETE_TCB; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * RFC 2960, 8.4 - Handle "Out of the blue" Packets + * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should + * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. + * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB + * packet must fill in the Verification Tag field of the outbound + * packet with the Verification Tag received in the SHUTDOWN ACK and + * set the T-bit in the Chunk Flags to indicate that no TCB was + * found. Otherwise, + * + * 8) The receiver should respond to the sender of the OOTB packet with + * an ABORT. When sending the ABORT, the receiver of the OOTB packet + * MUST fill in the Verification Tag field of the outbound packet + * with the value found in the Verification Tag field of the OOTB + * packet and set the T-bit in the Chunk Flags to indicate that no + * TCB was found. After sending this ABORT, the receiver of the OOTB + * packet shall discard the OOTB packet and take no further action. + */ +sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sk_buff *skb = chunk->skb; + sctp_chunkhdr_t *ch; + __u8 *ch_end; + int ootb_shut_ack = 0; + + SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); + + ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; + do { + /* Break out if chunk length is less then minimal. */ + if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) + break; + + ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); + + if (SCTP_CID_SHUTDOWN_ACK == ch->type) + ootb_shut_ack = 1; + + /* RFC 2960, Section 3.3.7 + * Moreover, under any circumstances, an endpoint that + * receives an ABORT MUST NOT respond to that ABORT by + * sending an ABORT of its own. + */ + if (SCTP_CID_ABORT == ch->type) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + ch = (sctp_chunkhdr_t *) ch_end; + } while (ch_end < skb->tail); + + if (ootb_shut_ack) + sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); + else + sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); + + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); +} + +/* + * Handle an "Out of the blue" SHUTDOWN ACK. + * + * Section: 8.4 5) + * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should + * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. + * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB packet + * must fill in the Verification Tag field of the outbound packet with + * the Verification Tag received in the SHUTDOWN ACK and set the + * T-bit in the Chunk Flags to indicate that no TCB was found. + * + * Inputs + * (endpoint, asoc, type, arg, commands) + * + * Outputs + * (sctp_disposition_t) + * + * The return value is the disposition of the chunk. + */ +static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_packet *packet = NULL; + struct sctp_chunk *chunk = arg; + struct sctp_chunk *shut; + + packet = sctp_ootb_pkt_new(asoc, chunk); + + if (packet) { + /* Make an SHUTDOWN_COMPLETE. + * The T bit will be set if the asoc is NULL. + */ + shut = sctp_make_shutdown_complete(asoc, chunk); + if (!shut) { + sctp_ootb_pkt_free(packet); + return SCTP_DISPOSITION_NOMEM; + } + + /* Set the skb to the belonging sock for accounting. */ + shut->skb->sk = ep->base.sk; + + sctp_packet_append_chunk(packet, shut); + + sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, + SCTP_PACKET(packet)); + + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); + + /* If the chunk length is invalid, we don't want to process + * the reset of the packet. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + return SCTP_DISPOSITION_CONSUME; + } + + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. + * + * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK + * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the + * procedures in section 8.4 SHOULD be followed, in other words it + * should be treated as an Out Of The Blue packet. + * [This means that we do NOT check the Verification Tag on these + * chunks. --piggy ] + * + */ +sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* Although we do have an association in this case, it corresponds + * to a restarted association. So the packet is treated as an OOTB + * packet and the state function that handles OOTB SHUTDOWN_ACK is + * called with a NULL association. + */ + return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); +} + +/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ +sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_chunk *asconf_ack = NULL; + sctp_addiphdr_t *hdr; + __u32 serial; + + if (!sctp_vtag_verify(chunk, asoc)) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, + SCTP_NULL()); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + } + + /* Make sure that the ASCONF ADDIP chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + hdr = (sctp_addiphdr_t *)chunk->skb->data; + serial = ntohl(hdr->serial); + + /* ADDIP 4.2 C1) Compare the value of the serial number to the value + * the endpoint stored in a new association variable + * 'Peer-Serial-Number'. + */ + if (serial == asoc->peer.addip_serial + 1) { + /* ADDIP 4.2 C2) If the value found in the serial number is + * equal to the ('Peer-Serial-Number' + 1), the endpoint MUST + * do V1-V5. + */ + asconf_ack = sctp_process_asconf((struct sctp_association *) + asoc, chunk); + if (!asconf_ack) + return SCTP_DISPOSITION_NOMEM; + } else if (serial == asoc->peer.addip_serial) { + /* ADDIP 4.2 C3) If the value found in the serial number is + * equal to the value stored in the 'Peer-Serial-Number' + * IMPLEMENTATION NOTE: As an optimization a receiver may wish + * to save the last ASCONF-ACK for some predetermined period of + * time and instead of re-processing the ASCONF (with the same + * serial number) it may just re-transmit the ASCONF-ACK. + */ + if (asoc->addip_last_asconf_ack) + asconf_ack = asoc->addip_last_asconf_ack; + else + return SCTP_DISPOSITION_DISCARD; + } else { + /* ADDIP 4.2 C4) Otherwise, the ASCONF Chunk is discarded since + * it must be either a stale packet or from an attacker. + */ + return SCTP_DISPOSITION_DISCARD; + } + + /* ADDIP 4.2 C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent + * back to the source address contained in the IP header of the ASCONF + * being responded to. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); + + return SCTP_DISPOSITION_CONSUME; +} + +/* + * ADDIP Section 4.3 General rules for address manipulation + * When building TLV parameters for the ASCONF Chunk that will add or + * delete IP addresses the D0 to D13 rules should be applied: + */ +sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *asconf_ack = arg; + struct sctp_chunk *last_asconf = asoc->addip_last_asconf; + struct sctp_chunk *abort; + sctp_addiphdr_t *addip_hdr; + __u32 sent_serial, rcvd_serial; + + if (!sctp_vtag_verify(asconf_ack, asoc)) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, + SCTP_NULL()); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + } + + /* Make sure that the ADDIP chunk has a valid length. */ + if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; + rcvd_serial = ntohl(addip_hdr->serial); + + if (last_asconf) { + addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; + sent_serial = ntohl(addip_hdr->serial); + } else { + sent_serial = asoc->addip_serial - 1; + } + + /* D0) If an endpoint receives an ASCONF-ACK that is greater than or + * equal to the next serial number to be used but no ASCONF chunk is + * outstanding the endpoint MUST ABORT the association. Note that a + * sequence number is greater than if it is no more than 2^^31-1 + * larger than the current sequence number (using serial arithmetic). + */ + if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && + !(asoc->addip_last_asconf)) { + abort = sctp_make_abort(asoc, asconf_ack, + sizeof(sctp_errhdr_t)); + if (abort) { + sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, NULL, 0); + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(abort)); + } + /* We are going to ABORT, so we might as well stop + * processing the rest of the chunks in the packet. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); + sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_ASCONF_ACK)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + return SCTP_DISPOSITION_ABORT; + } + + if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); + + if (!sctp_process_asconf_ack((struct sctp_association *)asoc, + asconf_ack)) + return SCTP_DISPOSITION_CONSUME; + + abort = sctp_make_abort(asoc, asconf_ack, + sizeof(sctp_errhdr_t)); + if (abort) { + sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, NULL, 0); + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(abort)); + } + /* We are going to ABORT, so we might as well stop + * processing the rest of the chunks in the packet. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_ASCONF_ACK)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + return SCTP_DISPOSITION_ABORT; + } + + return SCTP_DISPOSITION_DISCARD; +} + +/* + * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP + * + * When a FORWARD TSN chunk arrives, the data receiver MUST first update + * its cumulative TSN point to the value carried in the FORWARD TSN + * chunk, and then MUST further advance its cumulative TSN point locally + * if possible. + * After the above processing, the data receiver MUST stop reporting any + * missing TSNs earlier than or equal to the new cumulative TSN point. + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_fwdtsn_hdr *fwdtsn_hdr; + __u16 len; + __u32 tsn; + + if (!sctp_vtag_verify(chunk, asoc)) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, + SCTP_NULL()); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + } + + /* Make sure that the FORWARD_TSN chunk has valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; + chunk->subh.fwdtsn_hdr = fwdtsn_hdr; + len = ntohs(chunk->chunk_hdr->length); + len -= sizeof(struct sctp_chunkhdr); + skb_pull(chunk->skb, len); + + tsn = ntohl(fwdtsn_hdr->new_cum_tsn); + SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); + + /* The TSN is too high--silently discard the chunk and count on it + * getting retransmitted later. + */ + if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) + goto discard_noforce; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); + if (len > sizeof(struct sctp_fwdtsn_hdr)) + sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, + SCTP_CHUNK(chunk)); + + /* Count this as receiving DATA. */ + if (asoc->autoclose) { + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); + } + + /* FIXME: For now send a SACK, but DATA processing may + * send another. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); + /* Start the SACK timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); + + return SCTP_DISPOSITION_CONSUME; + +discard_noforce: + return SCTP_DISPOSITION_DISCARD; +} + +sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_fwdtsn_hdr *fwdtsn_hdr; + __u16 len; + __u32 tsn; + + if (!sctp_vtag_verify(chunk, asoc)) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, + SCTP_NULL()); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + } + + /* Make sure that the FORWARD_TSN chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; + chunk->subh.fwdtsn_hdr = fwdtsn_hdr; + len = ntohs(chunk->chunk_hdr->length); + len -= sizeof(struct sctp_chunkhdr); + skb_pull(chunk->skb, len); + + tsn = ntohl(fwdtsn_hdr->new_cum_tsn); + SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); + + /* The TSN is too high--silently discard the chunk and count on it + * getting retransmitted later. + */ + if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) + goto gen_shutdown; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); + if (len > sizeof(struct sctp_fwdtsn_hdr)) + sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, + SCTP_CHUNK(chunk)); + + /* Go a head and force a SACK, since we are shutting down. */ +gen_shutdown: + /* Implementor's Guide. + * + * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately + * respond to each received packet containing one or more DATA chunk(s) + * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer + */ + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + + return SCTP_DISPOSITION_CONSUME; +} + +/* + * Process an unknown chunk. + * + * Section: 3.2. Also, 2.1 in the implementor's guide. + * + * Chunk Types are encoded such that the highest-order two bits specify + * the action that must be taken if the processing endpoint does not + * recognize the Chunk Type. + * + * 00 - Stop processing this SCTP packet and discard it, do not process + * any further chunks within it. + * + * 01 - Stop processing this SCTP packet and discard it, do not process + * any further chunks within it, and report the unrecognized + * chunk in an 'Unrecognized Chunk Type'. + * + * 10 - Skip this chunk and continue processing. + * + * 11 - Skip this chunk and continue processing, but report in an ERROR + * Chunk using the 'Unrecognized Chunk Type' cause of error. + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *unk_chunk = arg; + struct sctp_chunk *err_chunk; + sctp_chunkhdr_t *hdr; + + SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); + + if (!sctp_vtag_verify(unk_chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the chunk has a valid length. + * Since we don't know the chunk type, we use a general + * chunkhdr structure to make a comparison. + */ + if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + switch (type.chunk & SCTP_CID_ACTION_MASK) { + case SCTP_CID_ACTION_DISCARD: + /* Discard the packet. */ + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + break; + case SCTP_CID_ACTION_DISCARD_ERR: + /* Discard the packet. */ + sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Generate an ERROR chunk as response. */ + hdr = unk_chunk->chunk_hdr; + err_chunk = sctp_make_op_error(asoc, unk_chunk, + SCTP_ERROR_UNKNOWN_CHUNK, hdr, + WORD_ROUND(ntohs(hdr->length))); + if (err_chunk) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(err_chunk)); + } + return SCTP_DISPOSITION_CONSUME; + break; + case SCTP_CID_ACTION_SKIP: + /* Skip the chunk. */ + return SCTP_DISPOSITION_DISCARD; + break; + case SCTP_CID_ACTION_SKIP_ERR: + /* Generate an ERROR chunk as response. */ + hdr = unk_chunk->chunk_hdr; + err_chunk = sctp_make_op_error(asoc, unk_chunk, + SCTP_ERROR_UNKNOWN_CHUNK, hdr, + WORD_ROUND(ntohs(hdr->length))); + if (err_chunk) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(err_chunk)); + } + /* Skip the chunk. */ + return SCTP_DISPOSITION_CONSUME; + break; + default: + break; + } + + return SCTP_DISPOSITION_DISCARD; +} + +/* + * Discard the chunk. + * + * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 + * [Too numerous to mention...] + * Verification Tag: No verification needed. + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); + return SCTP_DISPOSITION_DISCARD; +} + +/* + * Discard the whole packet. + * + * Section: 8.4 2) + * + * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST + * silently discard the OOTB packet and take no further action. + * Otherwise, + * + * Verification Tag: No verification necessary + * + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); + + return SCTP_DISPOSITION_CONSUME; +} + + +/* + * The other end is violating protocol. + * + * Section: Not specified + * Verification Tag: Not specified + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (asoc, reply_msg, msg_up, timers, counters) + * + * We simply tag the chunk as a violation. The state machine will log + * the violation and continue. + */ +sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + return SCTP_DISPOSITION_VIOLATION; +} + + +/* + * Handle a protocol violation when the chunk length is invalid. + * "Invalid" length is identified as smaller then the minimal length a + * given chunk can be. For example, a SACK chunk has invalid length + * if it's length is set to be smaller then the size of sctp_sack_chunk_t. + * + * We inform the other end by sending an ABORT with a Protocol Violation + * error code. + * + * Section: Not specified + * Verification Tag: Nothing to do + * Inputs + * (endpoint, asoc, chunk) + * + * Outputs + * (reply_msg, msg_up, counters) + * + * Generate an ABORT chunk and terminate the association. + */ +sctp_disposition_t sctp_sf_violation_chunklen(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + struct sctp_chunk *abort = NULL; + char err_str[]="The following chunk had invalid length:"; + + /* Make the abort chunk. */ + abort = sctp_make_abort_violation(asoc, chunk, err_str, + sizeof(err_str)); + if (!abort) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); + + if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); + sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, + SCTP_U32(SCTP_ERROR_PROTO_VIOLATION)); + } else { + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_PROTO_VIOLATION)); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + } + + sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); + + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + + return SCTP_DISPOSITION_ABORT; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/*************************************************************************** + * These are the state functions for handling primitive (Section 10) events. + ***************************************************************************/ +/* + * sctp_sf_do_prm_asoc + * + * Section: 10.1 ULP-to-SCTP + * B) Associate + * + * Format: ASSOCIATE(local SCTP instance name, destination transport addr, + * outbound stream count) + * -> association id [,destination transport addr list] [,outbound stream + * count] + * + * This primitive allows the upper layer to initiate an association to a + * specific peer endpoint. + * + * The peer endpoint shall be specified by one of the transport addresses + * which defines the endpoint (see Section 1.4). If the local SCTP + * instance has not been initialized, the ASSOCIATE is considered an + * error. + * [This is not relevant for the kernel implementation since we do all + * initialization at boot time. It we hadn't initialized we wouldn't + * get anywhere near this code.] + * + * An association id, which is a local handle to the SCTP association, + * will be returned on successful establishment of the association. If + * SCTP is not able to open an SCTP association with the peer endpoint, + * an error is returned. + * [In the kernel implementation, the struct sctp_association needs to + * be created BEFORE causing this primitive to run.] + * + * Other association parameters may be returned, including the + * complete destination transport addresses of the peer as well as the + * outbound stream count of the local endpoint. One of the transport + * address from the returned destination addresses will be selected by + * the local endpoint as default primary path for sending SCTP packets + * to this peer. The returned "destination transport addr list" can + * be used by the ULP to change the default primary path or to force + * sending a packet to a specific transport address. [All of this + * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING + * function.] + * + * Mandatory attributes: + * + * o local SCTP instance name - obtained from the INITIALIZE operation. + * [This is the argument asoc.] + * o destination transport addr - specified as one of the transport + * addresses of the peer endpoint with which the association is to be + * established. + * [This is asoc->peer.active_path.] + * o outbound stream count - the number of outbound streams the ULP + * would like to open towards this peer endpoint. + * [BUG: This is not currently implemented.] + * Optional attributes: + * + * None. + * + * The return value is a disposition. + */ +sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *repl; + + /* The comment below says that we enter COOKIE-WAIT AFTER + * sending the INIT, but that doesn't actually work in our + * implementation... + */ + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); + + /* RFC 2960 5.1 Normal Establishment of an Association + * + * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" + * must provide its Verification Tag (Tag_A) in the Initiate + * Tag field. Tag_A SHOULD be a random number in the range of + * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... + */ + + repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); + if (!repl) + goto nomem; + + /* Cast away the const modifier, as we want to just + * rerun it through as a sideffect. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, + SCTP_ASOC((struct sctp_association *) asoc)); + + /* After sending the INIT, "A" starts the T1-init timer and + * enters the COOKIE-WAIT state. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); + return SCTP_DISPOSITION_CONSUME; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Process the SEND primitive. + * + * Section: 10.1 ULP-to-SCTP + * E) Send + * + * Format: SEND(association id, buffer address, byte count [,context] + * [,stream id] [,life time] [,destination transport address] + * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) + * -> result + * + * This is the main method to send user data via SCTP. + * + * Mandatory attributes: + * + * o association id - local handle to the SCTP association + * + * o buffer address - the location where the user message to be + * transmitted is stored; + * + * o byte count - The size of the user data in number of bytes; + * + * Optional attributes: + * + * o context - an optional 32 bit integer that will be carried in the + * sending failure notification to the ULP if the transportation of + * this User Message fails. + * + * o stream id - to indicate which stream to send the data on. If not + * specified, stream 0 will be used. + * + * o life time - specifies the life time of the user data. The user data + * will not be sent by SCTP after the life time expires. This + * parameter can be used to avoid efforts to transmit stale + * user messages. SCTP notifies the ULP if the data cannot be + * initiated to transport (i.e. sent to the destination via SCTP's + * send primitive) within the life time variable. However, the + * user data will be transmitted if SCTP has attempted to transmit a + * chunk before the life time expired. + * + * o destination transport address - specified as one of the destination + * transport addresses of the peer endpoint to which this packet + * should be sent. Whenever possible, SCTP should use this destination + * transport address for sending the packets, instead of the current + * primary path. + * + * o unorder flag - this flag, if present, indicates that the user + * would like the data delivered in an unordered fashion to the peer + * (i.e., the U flag is set to 1 on all DATA chunks carrying this + * message). + * + * o no-bundle flag - instructs SCTP not to bundle this user data with + * other outbound DATA chunks. SCTP MAY still bundle even when + * this flag is present, when faced with network congestion. + * + * o payload protocol-id - A 32 bit unsigned integer that is to be + * passed to the peer indicating the type of payload protocol data + * being transmitted. This value is passed as opaque data by SCTP. + * + * The return value is the disposition. + */ +sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); + return SCTP_DISPOSITION_CONSUME; +} + +/* + * Process the SHUTDOWN primitive. + * + * Section: 10.1: + * C) Shutdown + * + * Format: SHUTDOWN(association id) + * -> result + * + * Gracefully closes an association. Any locally queued user data + * will be delivered to the peer. The association will be terminated only + * after the peer acknowledges all the SCTP packets sent. A success code + * will be returned on successful termination of the association. If + * attempting to terminate the association results in a failure, an error + * code shall be returned. + * + * Mandatory attributes: + * + * o association id - local handle to the SCTP association + * + * Optional attributes: + * + * None. + * + * The return value is the disposition. + */ +sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + int disposition; + + /* From 9.2 Shutdown of an Association + * Upon receipt of the SHUTDOWN primitive from its upper + * layer, the endpoint enters SHUTDOWN-PENDING state and + * remains there until all outstanding data has been + * acknowledged by its peer. The endpoint accepts no new data + * from its upper layer, but retransmits data to the far end + * if necessary to fill gaps. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); + + /* sctpimpguide-05 Section 2.12.2 + * The sender of the SHUTDOWN MAY also start an overall guard timer + * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, + SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); + + disposition = SCTP_DISPOSITION_CONSUME; + if (sctp_outq_is_empty(&asoc->outqueue)) { + disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, + arg, commands); + } + return disposition; +} + +/* + * Process the ABORT primitive. + * + * Section: 10.1: + * C) Abort + * + * Format: Abort(association id [, cause code]) + * -> result + * + * Ungracefully closes an association. Any locally queued user data + * will be discarded and an ABORT chunk is sent to the peer. A success code + * will be returned on successful abortion of the association. If + * attempting to abort the association results in a failure, an error + * code shall be returned. + * + * Mandatory attributes: + * + * o association id - local handle to the SCTP association + * + * Optional attributes: + * + * o cause code - reason of the abort to be passed to the peer + * + * None. + * + * The return value is the disposition. + */ +sctp_disposition_t sctp_sf_do_9_1_prm_abort( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* From 9.1 Abort of an Association + * Upon receipt of the ABORT primitive from its upper + * layer, the endpoint enters CLOSED state and + * discard all outstanding data has been + * acknowledged by its peer. The endpoint accepts no new data + * from its upper layer, but retransmits data to the far end + * if necessary to fill gaps. + */ + struct msghdr *msg = arg; + struct sctp_chunk *abort; + sctp_disposition_t retval; + + retval = SCTP_DISPOSITION_CONSUME; + + /* Generate ABORT chunk to send the peer. */ + abort = sctp_make_abort_user(asoc, NULL, msg); + if (!abort) + retval = SCTP_DISPOSITION_NOMEM; + else + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); + + /* Even if we can't send the ABORT due to low memory delete the + * TCB. This is a departure from our typical NOMEM handling. + */ + + /* Delete the established association. */ + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_USER_ABORT)); + + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + + return retval; +} + +/* We tried an illegal operation on an association which is closed. */ +sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); + return SCTP_DISPOSITION_CONSUME; +} + +/* We tried an illegal operation on an association which is shutting + * down. + */ +sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, + SCTP_ERROR(-ESHUTDOWN)); + return SCTP_DISPOSITION_CONSUME; +} + +/* + * sctp_cookie_wait_prm_shutdown + * + * Section: 4 Note: 2 + * Verification Tag: + * Inputs + * (endpoint, asoc) + * + * The RFC does not explicitly address this issue, but is the route through the + * state table when someone issues a shutdown while in COOKIE_WAIT state. + * + * Outputs + * (timers) + */ +sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); + + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + + SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); + + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); + + return SCTP_DISPOSITION_DELETE_TCB; +} + +/* + * sctp_cookie_echoed_prm_shutdown + * + * Section: 4 Note: 2 + * Verification Tag: + * Inputs + * (endpoint, asoc) + * + * The RFC does not explcitly address this issue, but is the route through the + * state table when someone issues a shutdown while in COOKIE_ECHOED state. + * + * Outputs + * (timers) + */ +sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, sctp_cmd_seq_t *commands) +{ + /* There is a single T1 timer, so we should be able to use + * common function with the COOKIE-WAIT state. + */ + return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); +} + +/* + * sctp_sf_cookie_wait_prm_abort + * + * Section: 4 Note: 2 + * Verification Tag: + * Inputs + * (endpoint, asoc) + * + * The RFC does not explicitly address this issue, but is the route through the + * state table when someone issues an abort while in COOKIE_WAIT state. + * + * Outputs + * (timers) + */ +sctp_disposition_t sctp_sf_cookie_wait_prm_abort( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct msghdr *msg = arg; + struct sctp_chunk *abort; + sctp_disposition_t retval; + + /* Stop T1-init timer */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); + retval = SCTP_DISPOSITION_CONSUME; + + /* Generate ABORT chunk to send the peer */ + abort = sctp_make_abort_user(asoc, NULL, msg); + if (!abort) + retval = SCTP_DISPOSITION_NOMEM; + else + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); + + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + + /* Even if we can't send the ABORT due to low memory delete the + * TCB. This is a departure from our typical NOMEM handling. + */ + + /* Delete the established association. */ + sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, + SCTP_U32(SCTP_ERROR_USER_ABORT)); + + return retval; +} + +/* + * sctp_sf_cookie_echoed_prm_abort + * + * Section: 4 Note: 3 + * Verification Tag: + * Inputs + * (endpoint, asoc) + * + * The RFC does not explcitly address this issue, but is the route through the + * state table when someone issues an abort while in COOKIE_ECHOED state. + * + * Outputs + * (timers) + */ +sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* There is a single T1 timer, so we should be able to use + * common function with the COOKIE-WAIT state. + */ + return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); +} + +/* + * sctp_sf_shutdown_pending_prm_abort + * + * Inputs + * (endpoint, asoc) + * + * The RFC does not explicitly address this issue, but is the route through the + * state table when someone issues an abort while in SHUTDOWN-PENDING state. + * + * Outputs + * (timers) + */ +sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* Stop the T5-shutdown guard timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); + + return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); +} + +/* + * sctp_sf_shutdown_sent_prm_abort + * + * Inputs + * (endpoint, asoc) + * + * The RFC does not explicitly address this issue, but is the route through the + * state table when someone issues an abort while in SHUTDOWN-SENT state. + * + * Outputs + * (timers) + */ +sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* Stop the T2-shutdown timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + + /* Stop the T5-shutdown guard timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); + + return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); +} + +/* + * sctp_sf_cookie_echoed_prm_abort + * + * Inputs + * (endpoint, asoc) + * + * The RFC does not explcitly address this issue, but is the route through the + * state table when someone issues an abort while in COOKIE_ECHOED state. + * + * Outputs + * (timers) + */ +sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + /* The same T2 timer, so we should be able to use + * common function with the SHUTDOWN-SENT state. + */ + return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); +} + +/* + * Process the REQUESTHEARTBEAT primitive + * + * 10.1 ULP-to-SCTP + * J) Request Heartbeat + * + * Format: REQUESTHEARTBEAT(association id, destination transport address) + * + * -> result + * + * Instructs the local endpoint to perform a HeartBeat on the specified + * destination transport address of the given association. The returned + * result should indicate whether the transmission of the HEARTBEAT + * chunk to the destination address is successful. + * + * Mandatory attributes: + * + * o association id - local handle to the SCTP association + * + * o destination transport address - the transport address of the + * association on which a heartbeat should be issued. + */ +sctp_disposition_t sctp_sf_do_prm_requestheartbeat( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + return sctp_sf_heartbeat(ep, asoc, type, (struct sctp_transport *)arg, + commands); +} + +/* + * ADDIP Section 4.1 ASCONF Chunk Procedures + * When an endpoint has an ASCONF signaled change to be sent to the + * remote endpoint it should do A1 to A9 + */ +sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = arg; + + sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, + SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); + return SCTP_DISPOSITION_CONSUME; +} + +/* + * Ignore the primitive event + * + * The return value is the disposition of the primitive. + */ +sctp_disposition_t sctp_sf_ignore_primitive( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); + return SCTP_DISPOSITION_DISCARD; +} + +/*************************************************************************** + * These are the state functions for the OTHER events. + ***************************************************************************/ + +/* + * Start the shutdown negotiation. + * + * From Section 9.2: + * Once all its outstanding data has been acknowledged, the endpoint + * shall send a SHUTDOWN chunk to its peer including in the Cumulative + * TSN Ack field the last sequential TSN it has received from the peer. + * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT + * state. If the timer expires, the endpoint must re-send the SHUTDOWN + * with the updated last sequential TSN received from its peer. + * + * The return value is the disposition. + */ +sctp_disposition_t sctp_sf_do_9_2_start_shutdown( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *reply; + + /* Once all its outstanding data has been acknowledged, the + * endpoint shall send a SHUTDOWN chunk to its peer including + * in the Cumulative TSN Ack field the last sequential TSN it + * has received from the peer. + */ + reply = sctp_make_shutdown(asoc, NULL); + if (!reply) + goto nomem; + + /* Set the transport for the SHUTDOWN chunk and the timeout for the + * T2-shutdown timer. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); + + /* It shall then start the T2-shutdown timer */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + + if (asoc->autoclose) + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); + + /* and enter the SHUTDOWN-SENT state. */ + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); + + /* sctp-implguide 2.10 Issues with Heartbeating and failover + * + * HEARTBEAT ... is discontinued after sending either SHUTDOWN + * or SHUTDOWN-ACK. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + + return SCTP_DISPOSITION_CONSUME; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Generate a SHUTDOWN ACK now that everything is SACK'd. + * + * From Section 9.2: + * + * If it has no more outstanding DATA chunks, the SHUTDOWN receiver + * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, + * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the + * endpoint must re-send the SHUTDOWN ACK. + * + * The return value is the disposition. + */ +sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = (struct sctp_chunk *) arg; + struct sctp_chunk *reply; + + /* There are 2 ways of getting here: + * 1) called in response to a SHUTDOWN chunk + * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. + * + * For the case (2), the arg parameter is set to NULL. We need + * to check that we have a chunk before accessing it's fields. + */ + if (chunk) { + if (!sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + /* Make sure that the SHUTDOWN chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + } + + /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver + * shall send a SHUTDOWN ACK ... + */ + reply = sctp_make_shutdown_ack(asoc, chunk); + if (!reply) + goto nomem; + + /* Set the transport for the SHUTDOWN ACK chunk and the timeout for + * the T2-shutdown timer. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); + + /* and start/restart a T2-shutdown timer of its own, */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + + if (asoc->autoclose) + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); + + /* Enter the SHUTDOWN-ACK-SENT state. */ + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); + + /* sctp-implguide 2.10 Issues with Heartbeating and failover + * + * HEARTBEAT ... is discontinued after sending either SHUTDOWN + * or SHUTDOWN-ACK. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + + return SCTP_DISPOSITION_CONSUME; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * Ignore the event defined as other + * + * The return value is the disposition of the event. + */ +sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); + return SCTP_DISPOSITION_DISCARD; +} + +/************************************************************ + * These are the state functions for handling timeout events. + ************************************************************/ + +/* + * RTX Timeout + * + * Section: 6.3.3 Handle T3-rtx Expiration + * + * Whenever the retransmission timer T3-rtx expires for a destination + * address, do the following: + * [See below] + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_transport *transport = arg; + + if (asoc->overall_error_count >= asoc->max_retrans) { + /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_NO_ERROR)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + return SCTP_DISPOSITION_DELETE_TCB; + } + + /* E1) For the destination address for which the timer + * expires, adjust its ssthresh with rules defined in Section + * 7.2.3 and set the cwnd <- MTU. + */ + + /* E2) For the destination address for which the timer + * expires, set RTO <- RTO * 2 ("back off the timer"). The + * maximum value discussed in rule C7 above (RTO.max) may be + * used to provide an upper bound to this doubling operation. + */ + + /* E3) Determine how many of the earliest (i.e., lowest TSN) + * outstanding DATA chunks for the address for which the + * T3-rtx has expired will fit into a single packet, subject + * to the MTU constraint for the path corresponding to the + * destination transport address to which the retransmission + * is being sent (this may be different from the address for + * which the timer expires [see Section 6.4]). Call this + * value K. Bundle and retransmit those K DATA chunks in a + * single packet to the destination endpoint. + * + * Note: Any DATA chunks that were sent to the address for + * which the T3-rtx timer expired but did not fit in one MTU + * (rule E3 above), should be marked for retransmission and + * sent as soon as cwnd allows (normally when a SACK arrives). + */ + + /* NB: Rules E4 and F1 are implicit in R1. */ + sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); + + /* Do some failure management (Section 8.2). */ + sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); + + return SCTP_DISPOSITION_CONSUME; +} + +/* + * Generate delayed SACK on timeout + * + * Section: 6.2 Acknowledgement on Reception of DATA Chunks + * + * The guidelines on delayed acknowledgement algorithm specified in + * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an + * acknowledgement SHOULD be generated for at least every second packet + * (not every second DATA chunk) received, and SHOULD be generated + * within 200 ms of the arrival of any unacknowledged DATA chunk. In + * some situations it may be beneficial for an SCTP transmitter to be + * more conservative than the algorithms detailed in this document + * allow. However, an SCTP transmitter MUST NOT be more aggressive than + * the following algorithms allow. + */ +sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); + return SCTP_DISPOSITION_CONSUME; +} + +/* + * sctp_sf_t1_timer_expire + * + * Section: 4 Note: 2 + * Verification Tag: + * Inputs + * (endpoint, asoc) + * + * RFC 2960 Section 4 Notes + * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT + * and re-start the T1-init timer without changing state. This MUST + * be repeated up to 'Max.Init.Retransmits' times. After that, the + * endpoint MUST abort the initialization process and report the + * error to SCTP user. + * + * 3) If the T1-cookie timer expires, the endpoint MUST retransmit + * COOKIE ECHO and re-start the T1-cookie timer without changing + * state. This MUST be repeated up to 'Max.Init.Retransmits' times. + * After that, the endpoint MUST abort the initialization process and + * report the error to SCTP user. + * + * Outputs + * (timers, events) + * + */ +sctp_disposition_t sctp_sf_t1_timer_expire(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *repl; + struct sctp_bind_addr *bp; + sctp_event_timeout_t timer = (sctp_event_timeout_t) arg; + int timeout; + int attempts; + + timeout = asoc->timeouts[timer]; + attempts = asoc->counters[SCTP_COUNTER_INIT_ERROR] + 1; + repl = NULL; + + SCTP_DEBUG_PRINTK("Timer T1 expired.\n"); + + if (attempts < asoc->max_init_attempts) { + switch (timer) { + case SCTP_EVENT_TIMEOUT_T1_INIT: + bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; + repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); + break; + + case SCTP_EVENT_TIMEOUT_T1_COOKIE: + repl = sctp_make_cookie_echo(asoc, NULL); + break; + + default: + BUG(); + break; + }; + + if (!repl) + goto nomem; + + /* Issue a sideeffect to do the needed accounting. */ + sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, + SCTP_TO(timer)); + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); + } else { + sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, + SCTP_U32(SCTP_ERROR_NO_ERROR)); + return SCTP_DISPOSITION_DELETE_TCB; + } + + return SCTP_DISPOSITION_CONSUME; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN + * with the updated last sequential TSN received from its peer. + * + * An endpoint should limit the number of retransmissions of the + * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. + * If this threshold is exceeded the endpoint should destroy the TCB and + * MUST report the peer endpoint unreachable to the upper layer (and + * thus the association enters the CLOSED state). The reception of any + * packet from its peer (i.e. as the peer sends all of its queued DATA + * chunks) should clear the endpoint's retransmission count and restart + * the T2-Shutdown timer, giving its peer ample opportunity to transmit + * all of its queued DATA chunks that have not yet been sent. + */ +sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *reply = NULL; + + SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); + if (asoc->overall_error_count >= asoc->max_retrans) { + /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_NO_ERROR)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + return SCTP_DISPOSITION_DELETE_TCB; + } + + switch (asoc->state) { + case SCTP_STATE_SHUTDOWN_SENT: + reply = sctp_make_shutdown(asoc, NULL); + break; + + case SCTP_STATE_SHUTDOWN_ACK_SENT: + reply = sctp_make_shutdown_ack(asoc, NULL); + break; + + default: + BUG(); + break; + }; + + if (!reply) + goto nomem; + + /* Do some failure management (Section 8.2). */ + sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, + SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); + + /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for + * the T2-shutdown timer. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); + + /* Restart the T2-shutdown timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + return SCTP_DISPOSITION_CONSUME; + +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* + * ADDIP Section 4.1 ASCONF CHunk Procedures + * If the T4 RTO timer expires the endpoint should do B1 to B5 + */ +sctp_disposition_t sctp_sf_t4_timer_expire( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *chunk = asoc->addip_last_asconf; + struct sctp_transport *transport = chunk->transport; + + /* ADDIP 4.1 B1) Increment the error counters and perform path failure + * detection on the appropriate destination address as defined in + * RFC2960 [5] section 8.1 and 8.2. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); + + /* Reconfig T4 timer and transport. */ + sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); + + /* ADDIP 4.1 B2) Increment the association error counters and perform + * endpoint failure detection on the association as defined in + * RFC2960 [5] section 8.1 and 8.2. + * association error counter is incremented in SCTP_CMD_STRIKE. + */ + if (asoc->overall_error_count >= asoc->max_retrans) { + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_NO_ERROR)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + SCTP_INC_STATS(SCTP_MIB_CURRESTAB); + return SCTP_DISPOSITION_ABORT; + } + + /* ADDIP 4.1 B3) Back-off the destination address RTO value to which + * the ASCONF chunk was sent by doubling the RTO timer value. + * This is done in SCTP_CMD_STRIKE. + */ + + /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible + * choose an alternate destination address (please refer to RFC2960 + * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this + * chunk, it MUST be the same (including its serial number) as the last + * ASCONF sent. + */ + sctp_chunk_hold(asoc->addip_last_asconf); + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(asoc->addip_last_asconf)); + + /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different + * destination is selected, then the RTO used will be that of the new + * destination address. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, + SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); + + return SCTP_DISPOSITION_CONSUME; +} + +/* sctpimpguide-05 Section 2.12.2 + * The sender of the SHUTDOWN MAY also start an overall guard timer + * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. + * At the expiration of this timer the sender SHOULD abort the association + * by sending an ABORT chunk. + */ +sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_chunk *reply = NULL; + + SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); + + reply = sctp_make_abort(asoc, NULL, 0); + if (!reply) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_NO_ERROR)); + + return SCTP_DISPOSITION_DELETE_TCB; +nomem: + return SCTP_DISPOSITION_NOMEM; +} + +/* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, + * the association is automatically closed by starting the shutdown process. + * The work that needs to be done is same as when SHUTDOWN is initiated by + * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). + */ +sctp_disposition_t sctp_sf_autoclose_timer_expire( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + int disposition; + + /* From 9.2 Shutdown of an Association + * Upon receipt of the SHUTDOWN primitive from its upper + * layer, the endpoint enters SHUTDOWN-PENDING state and + * remains there until all outstanding data has been + * acknowledged by its peer. The endpoint accepts no new data + * from its upper layer, but retransmits data to the far end + * if necessary to fill gaps. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); + + /* sctpimpguide-05 Section 2.12.2 + * The sender of the SHUTDOWN MAY also start an overall guard timer + * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, + SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); + disposition = SCTP_DISPOSITION_CONSUME; + if (sctp_outq_is_empty(&asoc->outqueue)) { + disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, + arg, commands); + } + return disposition; +} + +/***************************************************************************** + * These are sa state functions which could apply to all types of events. + ****************************************************************************/ + +/* + * This table entry is not implemented. + * + * Inputs + * (endpoint, asoc, chunk) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + return SCTP_DISPOSITION_NOT_IMPL; +} + +/* + * This table entry represents a bug. + * + * Inputs + * (endpoint, asoc, chunk) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + return SCTP_DISPOSITION_BUG; +} + +/* + * This table entry represents the firing of a timer in the wrong state. + * Since timer deletion cannot be guaranteed a timer 'may' end up firing + * when the association is in the wrong state. This event should + * be ignored, so as to prevent any rearming of the timer. + * + * Inputs + * (endpoint, asoc, chunk) + * + * The return value is the disposition of the chunk. + */ +sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); + return SCTP_DISPOSITION_CONSUME; +} + +/******************************************************************** + * 2nd Level Abstractions + ********************************************************************/ + +/* Pull the SACK chunk based on the SACK header. */ +static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) +{ + struct sctp_sackhdr *sack; + unsigned int len; + __u16 num_blocks; + __u16 num_dup_tsns; + + /* Protect ourselves from reading too far into + * the skb from a bogus sender. + */ + sack = (struct sctp_sackhdr *) chunk->skb->data; + + num_blocks = ntohs(sack->num_gap_ack_blocks); + num_dup_tsns = ntohs(sack->num_dup_tsns); + len = sizeof(struct sctp_sackhdr); + len += (num_blocks + num_dup_tsns) * sizeof(__u32); + if (len > chunk->skb->len) + return NULL; + + skb_pull(chunk->skb, len); + + return sack; +} + +/* Create an ABORT packet to be sent as a response, with the specified + * error causes. + */ +static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + struct sctp_chunk *chunk, + const void *payload, + size_t paylen) +{ + struct sctp_packet *packet; + struct sctp_chunk *abort; + + packet = sctp_ootb_pkt_new(asoc, chunk); + + if (packet) { + /* Make an ABORT. + * The T bit will be set if the asoc is NULL. + */ + abort = sctp_make_abort(asoc, chunk, paylen); + if (!abort) { + sctp_ootb_pkt_free(packet); + return NULL; + } + /* Add specified error causes, i.e., payload, to the + * end of the chunk. + */ + sctp_addto_chunk(abort, paylen, payload); + + /* Set the skb to the belonging sock for accounting. */ + abort->skb->sk = ep->base.sk; + + sctp_packet_append_chunk(packet, abort); + + } + + return packet; +} + +/* Allocate a packet for responding in the OOTB conditions. */ +static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, + const struct sctp_chunk *chunk) +{ + struct sctp_packet *packet; + struct sctp_transport *transport; + __u16 sport; + __u16 dport; + __u32 vtag; + + /* Get the source and destination port from the inbound packet. */ + sport = ntohs(chunk->sctp_hdr->dest); + dport = ntohs(chunk->sctp_hdr->source); + + /* The V-tag is going to be the same as the inbound packet if no + * association exists, otherwise, use the peer's vtag. + */ + if (asoc) { + vtag = asoc->peer.i.init_tag; + } else { + /* Special case the INIT and stale COOKIE_ECHO as there is no + * vtag yet. + */ + switch(chunk->chunk_hdr->type) { + case SCTP_CID_INIT: + { + sctp_init_chunk_t *init; + + init = (sctp_init_chunk_t *)chunk->chunk_hdr; + vtag = ntohl(init->init_hdr.init_tag); + break; + } + default: + vtag = ntohl(chunk->sctp_hdr->vtag); + break; + } + } + + /* Make a transport for the bucket, Eliza... */ + transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); + if (!transport) + goto nomem; + + /* Cache a route for the transport with the chunk's destination as + * the source address. + */ + sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, + sctp_sk(sctp_get_ctl_sock())); + + packet = sctp_packet_init(&transport->packet, transport, sport, dport); + packet = sctp_packet_config(packet, vtag, 0); + + return packet; + +nomem: + return NULL; +} + +/* Free the packet allocated earlier for responding in the OOTB condition. */ +void sctp_ootb_pkt_free(struct sctp_packet *packet) +{ + sctp_transport_free(packet->transport); +} + +/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ +static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const struct sctp_chunk *chunk, + sctp_cmd_seq_t *commands, + struct sctp_chunk *err_chunk) +{ + struct sctp_packet *packet; + + if (err_chunk) { + packet = sctp_ootb_pkt_new(asoc, chunk); + if (packet) { + struct sctp_signed_cookie *cookie; + + /* Override the OOTB vtag from the cookie. */ + cookie = chunk->subh.cookie_hdr; + packet->vtag = cookie->c.peer_vtag; + + /* Set the skb to the belonging sock for accounting. */ + err_chunk->skb->sk = ep->base.sk; + sctp_packet_append_chunk(packet, err_chunk); + sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, + SCTP_PACKET(packet)); + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); + } else + sctp_chunk_free (err_chunk); + } +} + + +/* Process a data chunk */ +static int sctp_eat_data(const struct sctp_association *asoc, + struct sctp_chunk *chunk, + sctp_cmd_seq_t *commands) +{ + sctp_datahdr_t *data_hdr; + struct sctp_chunk *err; + size_t datalen; + sctp_verb_t deliver; + int tmp; + __u32 tsn; + + data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; + skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); + + tsn = ntohl(data_hdr->tsn); + SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); + + /* ASSERT: Now skb->data is really the user data. */ + + /* Process ECN based congestion. + * + * Since the chunk structure is reused for all chunks within + * a packet, we use ecn_ce_done to track if we've already + * done CE processing for this packet. + * + * We need to do ECN processing even if we plan to discard the + * chunk later. + */ + + if (!chunk->ecn_ce_done) { + struct sctp_af *af; + chunk->ecn_ce_done = 1; + + af = sctp_get_af_specific( + ipver2af(chunk->skb->nh.iph->version)); + + if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { + /* Do real work as sideffect. */ + sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, + SCTP_U32(tsn)); + } + } + + tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); + if (tmp < 0) { + /* The TSN is too high--silently discard the chunk and + * count on it getting retransmitted later. + */ + return SCTP_IERROR_HIGH_TSN; + } else if (tmp > 0) { + /* This is a duplicate. Record it. */ + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); + return SCTP_IERROR_DUP_TSN; + } + + /* This is a new TSN. */ + + /* Discard if there is no room in the receive window. + * Actually, allow a little bit of overflow (up to a MTU). + */ + datalen = ntohs(chunk->chunk_hdr->length); + datalen -= sizeof(sctp_data_chunk_t); + + deliver = SCTP_CMD_CHUNK_ULP; + + /* Think about partial delivery. */ + if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { + + /* Even if we don't accept this chunk there is + * memory pressure. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); + } + + /* Spill over rwnd a little bit. Note: While allowed, this spill over + * seems a bit troublesome in that frag_point varies based on + * PMTU. In cases, such as loopback, this might be a rather + * large spill over. + */ + if (!asoc->rwnd || asoc->rwnd_over || + (datalen > asoc->rwnd + asoc->frag_point)) { + + /* If this is the next TSN, consider reneging to make + * room. Note: Playing nice with a confused sender. A + * malicious sender can still eat up all our buffer + * space and in the future we may want to detect and + * do more drastic reneging. + */ + if (sctp_tsnmap_has_gap(&asoc->peer.tsn_map) && + (sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1) == tsn) { + SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); + deliver = SCTP_CMD_RENEGE; + } else { + SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " + "rwnd: %d\n", tsn, datalen, + asoc->rwnd); + return SCTP_IERROR_IGNORE_TSN; + } + } + + /* + * Section 3.3.10.9 No User Data (9) + * + * Cause of error + * --------------- + * No User Data: This error cause is returned to the originator of a + * DATA chunk if a received DATA chunk has no user data. + */ + if (unlikely(0 == datalen)) { + err = sctp_make_abort_no_data(asoc, chunk, tsn); + if (err) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(err)); + } + /* We are going to ABORT, so we might as well stop + * processing the rest of the chunks in the packet. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_U32(SCTP_ERROR_NO_DATA)); + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + return SCTP_IERROR_NO_DATA; + } + + /* If definately accepting the DATA chunk, record its TSN, otherwise + * wait for renege processing. + */ + if (SCTP_CMD_CHUNK_ULP == deliver) + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); + + /* Note: Some chunks may get overcounted (if we drop) or overcounted + * if we renege and the chunk arrives again. + */ + if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) + SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); + else + SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); + + /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number + * + * If an endpoint receive a DATA chunk with an invalid stream + * identifier, it shall acknowledge the reception of the DATA chunk + * following the normal procedure, immediately send an ERROR chunk + * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) + * and discard the DATA chunk. + */ + if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) { + err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, + &data_hdr->stream, + sizeof(data_hdr->stream)); + if (err) + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(err)); + return SCTP_IERROR_BAD_STREAM; + } + + /* Send the data up to the user. Note: Schedule the + * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK + * chunk needs the updated rwnd. + */ + sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); + + return SCTP_IERROR_NO_ERROR; +} |