sctp: Try not to change a_rwnd when faking a SACK from SHUTDOWN. (d4d6fb57) · Commits · 戴 / test

We currently set a_rwnd to 0 when faking a SACK from SHUTDOWN. This results in an hung association if the remote only uses SHUTDOWNs (which it's allowed to do) to acknowlege DATA when closing. The reason for that is that we simply honor the a_rwnd from the sack, but since we faked it to be 0, we enter 0-window probing. The fix is to use the peers old rwnd and add our flight size to it. Signed-off-by:

Vlad Yasevich <vladislav.yasevich@hp.com>

net/sctp/sm_sideeffect.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -1533,7 +1533,8 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
		case SCTP_CMD_PROCESS_CTSN:
		/* Dummy up a SACK for processing. */
		sackh.cum_tsn_ack = cmd->obj.be32;
		sackh.a_rwnd = 0;
		sackh.a_rwnd = asoc->peer.rwnd +
		asoc->outqueue.outstanding_bytes;
		sackh.num_gap_ack_blocks = 0;
		sackh.num_dup_tsns = 0;
		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
		@@ -1632,9 +1633,9 @@ out:
		*/
		if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
		if (chunk->end_of_packet \|\| chunk->singleton)
		sctp_outq_uncork(&asoc->outqueue);
		error = sctp_outq_uncork(&asoc->outqueue);
		} else if (local_cork)
		sctp_outq_uncork(&asoc->outqueue);
		error = sctp_outq_uncork(&asoc->outqueue);
		return error;
		nomem:
		error = -ENOMEM;

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