sctp: implement prsctp TTL policy

prsctp TTL policy is a policy to abandon chunks when they expire
at the specific time in local stack. It's similar with expires_at
in struct sctp_datamsg.

This patch uses sinfo->sinfo_timetolive to set the specific time for
TTL policy. sinfo->sinfo_timetolive is also used for msg->expires_at.
So if prsctp_enable or TTL policy is not enabled, msg->expires_at
still works as before.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index d8e464aacb20..6bcda715008e 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -602,6 +602,16 @@ struct sctp_chunk {
 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
 	struct sctp_sndrcvinfo sinfo;
 
+	/* We use this field to record param for prsctp policies,
+	 * for TTL policy, it is the time_to_drop of this chunk,
+	 * for RTX policy, it is the max_sent_count of this chunk,
+	 * for PRIO policy, it is the priority of this chunk.
+	 */
+	unsigned long prsctp_param;
+
+	/* How many times this chunk have been sent, for prsctp RTX policy */
+	int sent_count;
+
 	/* Which association does this belong to?  */
 	struct sctp_association *asoc;