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Commit c910b47e authored by Vlad Yasevich's avatar Vlad Yasevich Committed by Vladislav Yasevich
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[SCTP] Update pmtu handling to be similar to tcp 



Introduce new function sctp_transport_update_pmtu that updates
the transports and destination caches view of the path mtu.

Signed-off-by: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
Acked-by: default avatarSridhar Samudrala <sri@us.ibm.com>
parent fe979ac1

include/net/sctp/structs.h

+1 −0
Original line number Diff line number Diff line
@@ -1006,6 +1006,7 @@ void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32); 
void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);

unsigned long sctp_transport_timeout(struct sctp_transport *);

void sctp_transport_reset(struct sctp_transport *);

void sctp_transport_update_pmtu(struct sctp_transport *, u32);





/* This is the structure we use to queue packets as they come into

net/sctp/input.c

+2 −14
Original line number Diff line number Diff line
@@ -371,20 +371,8 @@ void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, 
		return;



	if (t->param_flags & SPP_PMTUD_ENABLE) {

		if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {

			printk(KERN_WARNING "%s: Reported pmtu %d too low, "

			       "using default minimum of %d\n",

			       __FUNCTION__, pmtu,

			       SCTP_DEFAULT_MINSEGMENT);

			/* Use default minimum segment size and disable

			 * pmtu discovery on this transport.

			 */

			t->pathmtu = SCTP_DEFAULT_MINSEGMENT;

			t->param_flags = (t->param_flags & ~SPP_PMTUD) |

				SPP_PMTUD_DISABLE;

		} else {

			t->pathmtu = pmtu;

		}

		/* Update transports view of the MTU */

		sctp_transport_update_pmtu(t, pmtu);



		/* Update association pmtu. */

		sctp_assoc_sync_pmtu(asoc);

net/sctp/transport.c

+41 −0
Original line number Diff line number Diff line
@@ -241,6 +241,47 @@ void sctp_transport_pmtu(struct sctp_transport *transport) 
		transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;

}



/* this is a complete rip-off from __sk_dst_check

 * the cookie is always 0 since this is how it's used in the

 * pmtu code

 */

static struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)

{

	struct dst_entry *dst = t->dst;



	if (dst && dst->obsolete && dst->ops->check(dst, 0) == NULL) {

		dst_release(t->dst);

		t->dst = NULL;

		return NULL;

	}



	return dst;

}



void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)

{

	struct dst_entry *dst;



	if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {

		printk(KERN_WARNING "%s: Reported pmtu %d too low, "

		       "using default minimum of %d\n",

		       __FUNCTION__, pmtu,

		       SCTP_DEFAULT_MINSEGMENT);

		/* Use default minimum segment size and disable

		 * pmtu discovery on this transport.

		 */

		t->pathmtu = SCTP_DEFAULT_MINSEGMENT;

		t->param_flags = (t->param_flags & ~SPP_PMTUD) |

			SPP_PMTUD_DISABLE;

	} else {

		t->pathmtu = pmtu;

	}



	dst = sctp_transport_dst_check(t);

	if (dst)

		dst->ops->update_pmtu(dst, pmtu);

}



/* Caches the dst entry and source address for a transport's destination

 * address.

 */