aboutsummaryrefslogtreecommitdiff
path: root/net/ipv6/exthdrs.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/ipv6/exthdrs.c')
-rw-r--r--net/ipv6/exthdrs.c575
1 files changed, 575 insertions, 0 deletions
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
new file mode 100644
index 00000000000..e0839eafc3a
--- /dev/null
+++ b/net/ipv6/exthdrs.c
@@ -0,0 +1,575 @@
+/*
+ * Extension Header handling for IPv6
+ * Linux INET6 implementation
+ *
+ * Authors:
+ * Pedro Roque <roque@di.fc.ul.pt>
+ * Andi Kleen <ak@muc.de>
+ * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
+ *
+ * $Id: exthdrs.c,v 1.13 2001/06/19 15:58:56 davem Exp $
+ *
+ * This program 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 of the License, or (at your option) any later version.
+ */
+
+/* Changes:
+ * yoshfuji : ensure not to overrun while parsing
+ * tlv options.
+ * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
+ * YOSHIFUJI Hideaki @USAGI Register inbound extension header
+ * handlers as inet6_protocol{}.
+ */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/sched.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/in6.h>
+#include <linux/icmpv6.h>
+
+#include <net/sock.h>
+#include <net/snmp.h>
+
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/rawv6.h>
+#include <net/ndisc.h>
+#include <net/ip6_route.h>
+#include <net/addrconf.h>
+
+#include <asm/uaccess.h>
+
+/*
+ * Parsing tlv encoded headers.
+ *
+ * Parsing function "func" returns 1, if parsing succeed
+ * and 0, if it failed.
+ * It MUST NOT touch skb->h.
+ */
+
+struct tlvtype_proc {
+ int type;
+ int (*func)(struct sk_buff *skb, int offset);
+};
+
+/*********************
+ Generic functions
+ *********************/
+
+/* An unknown option is detected, decide what to do */
+
+static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
+{
+ switch ((skb->nh.raw[optoff] & 0xC0) >> 6) {
+ case 0: /* ignore */
+ return 1;
+
+ case 1: /* drop packet */
+ break;
+
+ case 3: /* Send ICMP if not a multicast address and drop packet */
+ /* Actually, it is redundant check. icmp_send
+ will recheck in any case.
+ */
+ if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr))
+ break;
+ case 2: /* send ICMP PARM PROB regardless and drop packet */
+ icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
+ return 0;
+ };
+
+ kfree_skb(skb);
+ return 0;
+}
+
+/* Parse tlv encoded option header (hop-by-hop or destination) */
+
+static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
+{
+ struct tlvtype_proc *curr;
+ int off = skb->h.raw - skb->nh.raw;
+ int len = ((skb->h.raw[1]+1)<<3);
+
+ if ((skb->h.raw + len) - skb->data > skb_headlen(skb))
+ goto bad;
+
+ off += 2;
+ len -= 2;
+
+ while (len > 0) {
+ int optlen = skb->nh.raw[off+1]+2;
+
+ switch (skb->nh.raw[off]) {
+ case IPV6_TLV_PAD0:
+ optlen = 1;
+ break;
+
+ case IPV6_TLV_PADN:
+ break;
+
+ default: /* Other TLV code so scan list */
+ if (optlen > len)
+ goto bad;
+ for (curr=procs; curr->type >= 0; curr++) {
+ if (curr->type == skb->nh.raw[off]) {
+ /* type specific length/alignment
+ checks will be performed in the
+ func(). */
+ if (curr->func(skb, off) == 0)
+ return 0;
+ break;
+ }
+ }
+ if (curr->type < 0) {
+ if (ip6_tlvopt_unknown(skb, off) == 0)
+ return 0;
+ }
+ break;
+ }
+ off += optlen;
+ len -= optlen;
+ }
+ if (len == 0)
+ return 1;
+bad:
+ kfree_skb(skb);
+ return 0;
+}
+
+/*****************************
+ Destination options header.
+ *****************************/
+
+static struct tlvtype_proc tlvprocdestopt_lst[] = {
+ /* No destination options are defined now */
+ {-1, NULL}
+};
+
+static int ipv6_destopt_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
+{
+ struct sk_buff *skb = *skbp;
+ struct inet6_skb_parm *opt = IP6CB(skb);
+
+ if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+8) ||
+ !pskb_may_pull(skb, (skb->h.raw-skb->data)+((skb->h.raw[1]+1)<<3))) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+
+ opt->dst1 = skb->h.raw - skb->nh.raw;
+
+ if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
+ skb->h.raw += ((skb->h.raw[1]+1)<<3);
+ *nhoffp = opt->dst1;
+ return 1;
+ }
+
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ return -1;
+}
+
+static struct inet6_protocol destopt_protocol = {
+ .handler = ipv6_destopt_rcv,
+ .flags = INET6_PROTO_NOPOLICY,
+};
+
+void __init ipv6_destopt_init(void)
+{
+ if (inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS) < 0)
+ printk(KERN_ERR "ipv6_destopt_init: Could not register protocol\n");
+}
+
+/********************************
+ NONE header. No data in packet.
+ ********************************/
+
+static int ipv6_nodata_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
+{
+ struct sk_buff *skb = *skbp;
+
+ kfree_skb(skb);
+ return 0;
+}
+
+static struct inet6_protocol nodata_protocol = {
+ .handler = ipv6_nodata_rcv,
+ .flags = INET6_PROTO_NOPOLICY,
+};
+
+void __init ipv6_nodata_init(void)
+{
+ if (inet6_add_protocol(&nodata_protocol, IPPROTO_NONE) < 0)
+ printk(KERN_ERR "ipv6_nodata_init: Could not register protocol\n");
+}
+
+/********************************
+ Routing header.
+ ********************************/
+
+static int ipv6_rthdr_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
+{
+ struct sk_buff *skb = *skbp;
+ struct inet6_skb_parm *opt = IP6CB(skb);
+ struct in6_addr *addr;
+ struct in6_addr daddr;
+ int n, i;
+
+ struct ipv6_rt_hdr *hdr;
+ struct rt0_hdr *rthdr;
+
+ if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+8) ||
+ !pskb_may_pull(skb, (skb->h.raw-skb->data)+((skb->h.raw[1]+1)<<3))) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+
+ hdr = (struct ipv6_rt_hdr *) skb->h.raw;
+
+ if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr) ||
+ skb->pkt_type != PACKET_HOST) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+
+looped_back:
+ if (hdr->segments_left == 0) {
+ opt->srcrt = skb->h.raw - skb->nh.raw;
+ skb->h.raw += (hdr->hdrlen + 1) << 3;
+ opt->dst0 = opt->dst1;
+ opt->dst1 = 0;
+ *nhoffp = (&hdr->nexthdr) - skb->nh.raw;
+ return 1;
+ }
+
+ if (hdr->type != IPV6_SRCRT_TYPE_0) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->type) - skb->nh.raw);
+ return -1;
+ }
+
+ if (hdr->hdrlen & 0x01) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->hdrlen) - skb->nh.raw);
+ return -1;
+ }
+
+ /*
+ * This is the routing header forwarding algorithm from
+ * RFC 2460, page 16.
+ */
+
+ n = hdr->hdrlen >> 1;
+
+ if (hdr->segments_left > n) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->segments_left) - skb->nh.raw);
+ return -1;
+ }
+
+ /* We are about to mangle packet header. Be careful!
+ Do not damage packets queued somewhere.
+ */
+ if (skb_cloned(skb)) {
+ struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
+ kfree_skb(skb);
+ /* the copy is a forwarded packet */
+ if (skb2 == NULL) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_OUTDISCARDS);
+ return -1;
+ }
+ *skbp = skb = skb2;
+ opt = IP6CB(skb2);
+ hdr = (struct ipv6_rt_hdr *) skb2->h.raw;
+ }
+
+ if (skb->ip_summed == CHECKSUM_HW)
+ skb->ip_summed = CHECKSUM_NONE;
+
+ i = n - --hdr->segments_left;
+
+ rthdr = (struct rt0_hdr *) hdr;
+ addr = rthdr->addr;
+ addr += i - 1;
+
+ if (ipv6_addr_is_multicast(addr)) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+
+ ipv6_addr_copy(&daddr, addr);
+ ipv6_addr_copy(addr, &skb->nh.ipv6h->daddr);
+ ipv6_addr_copy(&skb->nh.ipv6h->daddr, &daddr);
+
+ dst_release(xchg(&skb->dst, NULL));
+ ip6_route_input(skb);
+ if (skb->dst->error) {
+ skb_push(skb, skb->data - skb->nh.raw);
+ dst_input(skb);
+ return -1;
+ }
+
+ if (skb->dst->dev->flags&IFF_LOOPBACK) {
+ if (skb->nh.ipv6h->hop_limit <= 1) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
+ 0, skb->dev);
+ kfree_skb(skb);
+ return -1;
+ }
+ skb->nh.ipv6h->hop_limit--;
+ goto looped_back;
+ }
+
+ skb_push(skb, skb->data - skb->nh.raw);
+ dst_input(skb);
+ return -1;
+}
+
+static struct inet6_protocol rthdr_protocol = {
+ .handler = ipv6_rthdr_rcv,
+ .flags = INET6_PROTO_NOPOLICY,
+};
+
+void __init ipv6_rthdr_init(void)
+{
+ if (inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING) < 0)
+ printk(KERN_ERR "ipv6_rthdr_init: Could not register protocol\n");
+};
+
+/*
+ This function inverts received rthdr.
+ NOTE: specs allow to make it automatically only if
+ packet authenticated.
+
+ I will not discuss it here (though, I am really pissed off at
+ this stupid requirement making rthdr idea useless)
+
+ Actually, it creates severe problems for us.
+ Embryonic requests has no associated sockets,
+ so that user have no control over it and
+ cannot not only to set reply options, but
+ even to know, that someone wants to connect
+ without success. :-(
+
+ For now we need to test the engine, so that I created
+ temporary (or permanent) backdoor.
+ If listening socket set IPV6_RTHDR to 2, then we invert header.
+ --ANK (980729)
+ */
+
+struct ipv6_txoptions *
+ipv6_invert_rthdr(struct sock *sk, struct ipv6_rt_hdr *hdr)
+{
+ /* Received rthdr:
+
+ [ H1 -> H2 -> ... H_prev ] daddr=ME
+
+ Inverted result:
+ [ H_prev -> ... -> H1 ] daddr =sender
+
+ Note, that IP output engine will rewrite this rthdr
+ by rotating it left by one addr.
+ */
+
+ int n, i;
+ struct rt0_hdr *rthdr = (struct rt0_hdr*)hdr;
+ struct rt0_hdr *irthdr;
+ struct ipv6_txoptions *opt;
+ int hdrlen = ipv6_optlen(hdr);
+
+ if (hdr->segments_left ||
+ hdr->type != IPV6_SRCRT_TYPE_0 ||
+ hdr->hdrlen & 0x01)
+ return NULL;
+
+ n = hdr->hdrlen >> 1;
+ opt = sock_kmalloc(sk, sizeof(*opt) + hdrlen, GFP_ATOMIC);
+ if (opt == NULL)
+ return NULL;
+ memset(opt, 0, sizeof(*opt));
+ opt->tot_len = sizeof(*opt) + hdrlen;
+ opt->srcrt = (void*)(opt+1);
+ opt->opt_nflen = hdrlen;
+
+ memcpy(opt->srcrt, hdr, sizeof(*hdr));
+ irthdr = (struct rt0_hdr*)opt->srcrt;
+ /* Obsolete field, MBZ, when originated by us */
+ irthdr->bitmap = 0;
+ opt->srcrt->segments_left = n;
+ for (i=0; i<n; i++)
+ memcpy(irthdr->addr+i, rthdr->addr+(n-1-i), 16);
+ return opt;
+}
+
+/**********************************
+ Hop-by-hop options.
+ **********************************/
+
+/* Router Alert as of RFC 2711 */
+
+static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
+{
+ if (skb->nh.raw[optoff+1] == 2) {
+ IP6CB(skb)->ra = optoff;
+ return 1;
+ }
+ LIMIT_NETDEBUG(
+ printk(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n", skb->nh.raw[optoff+1]));
+ kfree_skb(skb);
+ return 0;
+}
+
+/* Jumbo payload */
+
+static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
+{
+ u32 pkt_len;
+
+ if (skb->nh.raw[optoff+1] != 4 || (optoff&3) != 2) {
+ LIMIT_NETDEBUG(
+ printk(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", skb->nh.raw[optoff+1]));
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ goto drop;
+ }
+
+ pkt_len = ntohl(*(u32*)(skb->nh.raw+optoff+2));
+ if (pkt_len <= IPV6_MAXPLEN) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
+ return 0;
+ }
+ if (skb->nh.ipv6h->payload_len) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
+ return 0;
+ }
+
+ if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
+ IP6_INC_STATS_BH(IPSTATS_MIB_INTRUNCATEDPKTS);
+ goto drop;
+ }
+ if (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
+ __pskb_trim(skb, pkt_len + sizeof(struct ipv6hdr));
+ if (skb->ip_summed == CHECKSUM_HW)
+ skb->ip_summed = CHECKSUM_NONE;
+ }
+ return 1;
+
+drop:
+ kfree_skb(skb);
+ return 0;
+}
+
+static struct tlvtype_proc tlvprochopopt_lst[] = {
+ {
+ .type = IPV6_TLV_ROUTERALERT,
+ .func = ipv6_hop_ra,
+ },
+ {
+ .type = IPV6_TLV_JUMBO,
+ .func = ipv6_hop_jumbo,
+ },
+ { -1, }
+};
+
+int ipv6_parse_hopopts(struct sk_buff *skb, int nhoff)
+{
+ IP6CB(skb)->hop = sizeof(struct ipv6hdr);
+ if (ip6_parse_tlv(tlvprochopopt_lst, skb))
+ return sizeof(struct ipv6hdr);
+ return -1;
+}
+
+/*
+ * Creating outbound headers.
+ *
+ * "build" functions work when skb is filled from head to tail (datagram)
+ * "push" functions work when headers are added from tail to head (tcp)
+ *
+ * In both cases we assume, that caller reserved enough room
+ * for headers.
+ */
+
+static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
+ struct ipv6_rt_hdr *opt,
+ struct in6_addr **addr_p)
+{
+ struct rt0_hdr *phdr, *ihdr;
+ int hops;
+
+ ihdr = (struct rt0_hdr *) opt;
+
+ phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
+ memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
+
+ hops = ihdr->rt_hdr.hdrlen >> 1;
+
+ if (hops > 1)
+ memcpy(phdr->addr, ihdr->addr + 1,
+ (hops - 1) * sizeof(struct in6_addr));
+
+ ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
+ *addr_p = ihdr->addr;
+
+ phdr->rt_hdr.nexthdr = *proto;
+ *proto = NEXTHDR_ROUTING;
+}
+
+static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
+{
+ struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
+
+ memcpy(h, opt, ipv6_optlen(opt));
+ h->nexthdr = *proto;
+ *proto = type;
+}
+
+void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
+ u8 *proto,
+ struct in6_addr **daddr)
+{
+ if (opt->srcrt)
+ ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
+ if (opt->dst0opt)
+ ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
+ if (opt->hopopt)
+ ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
+}
+
+void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
+{
+ if (opt->dst1opt)
+ ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
+}
+
+struct ipv6_txoptions *
+ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
+{
+ struct ipv6_txoptions *opt2;
+
+ opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
+ if (opt2) {
+ long dif = (char*)opt2 - (char*)opt;
+ memcpy(opt2, opt, opt->tot_len);
+ if (opt2->hopopt)
+ *((char**)&opt2->hopopt) += dif;
+ if (opt2->dst0opt)
+ *((char**)&opt2->dst0opt) += dif;
+ if (opt2->dst1opt)
+ *((char**)&opt2->dst1opt) += dif;
+ if (opt2->srcrt)
+ *((char**)&opt2->srcrt) += dif;
+ }
+ return opt2;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-27 09:24:38 +0000