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authorVlad Yasevich <vladislav.yasevich@hp.com>2008-06-19 16:08:18 -0700
committerDavid S. Miller <davem@davemloft.net>2008-06-19 16:08:18 -0700
commit2e3216cd54b142ba605e87522e15f42e0c4e3996 (patch)
treeda4d7a6ff4811d9f38b81c70f08b221b575e1254 /net/sctp/sm_sideeffect.c
parent7115e632f90952454ab6426e0d2151327162a30f (diff)
sctp: Follow security requirement of responding with 1 packet
RFC 4960, Section 11.4. Protection of Non-SCTP-Capable Hosts When an SCTP stack receives a packet containing multiple control or DATA chunks and the processing of the packet requires the sending of multiple chunks in response, the sender of the response chunk(s) MUST NOT send more than one packet. If bundling is supported, multiple response chunks that fit into a single packet MAY be bundled together into one single response packet. If bundling is not supported, then the sender MUST NOT send more than one response chunk and MUST discard all other responses. Note that this rule does NOT apply to a SACK chunk, since a SACK chunk is, in itself, a response to DATA and a SACK does not require a response of more DATA. We implement this by not servicing our outqueue until we reach the end of the packet. This enables maximum bundling. We also identify 'response' chunks and make sure that we only send 1 packet when sending such chunks. Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp/sm_sideeffect.c')
-rw-r--r--net/sctp/sm_sideeffect.c27
1 files changed, 18 insertions, 9 deletions
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index b083312c725..9732c797e8e 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -664,7 +664,7 @@ static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_sackhdr *sackh)
{
- int err;
+ int err = 0;
if (sctp_outq_sack(&asoc->outqueue, sackh)) {
/* There are no more TSNs awaiting SACK. */
@@ -672,11 +672,6 @@ static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
asoc->state, asoc->ep, asoc, NULL,
GFP_ATOMIC);
- } else {
- /* Windows may have opened, so we need
- * to check if we have DATA to transmit
- */
- err = sctp_outq_flush(&asoc->outqueue, 0);
}
return err;
@@ -1481,8 +1476,15 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
break;
case SCTP_CMD_DISCARD_PACKET:
- /* We need to discard the whole packet. */
+ /* We need to discard the whole packet.
+ * Uncork the queue since there might be
+ * responses pending
+ */
chunk->pdiscard = 1;
+ if (asoc) {
+ sctp_outq_uncork(&asoc->outqueue);
+ local_cork = 0;
+ }
break;
case SCTP_CMD_RTO_PENDING:
@@ -1553,8 +1555,15 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
}
out:
- if (local_cork)
- sctp_outq_uncork(&asoc->outqueue);
+ /* If this is in response to a received chunk, wait until
+ * we are done with the packet to open the queue so that we don't
+ * send multiple packets in response to a single request.
+ */
+ if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
+ if (chunk->end_of_packet || chunk->singleton)
+ sctp_outq_uncork(&asoc->outqueue);
+ } else if (local_cork)
+ sctp_outq_uncork(&asoc->outqueue);
return error;
nomem:
error = -ENOMEM;