MFC r283666:

Report the MTU consistently as specified in
https://tools.ietf.org/html/rfc6458
Thanks to Irene Ruengeler for helping me to fix this bug.

1 files changed, 74 insertions, 25 deletions

diff --git a/sys/netinet/sctp_usrreq.c b/sys/netinet/sctp_usrreq.c
index 5005910..2a59e13 100644
--- a/sys/netinet/sctp_usrreq.c
+++ b/sys/netinet/sctp_usrreq.c
@@ -2439,17 +2439,23 @@ flags_out:
 				/* Applies to the specific association */
 				paddrp->spp_flags = 0;
 				if (net != NULL) {
-					int ovh;
-
-					if (inp->sctp_flags & SCTP_PCB_FLAGS_BOUND_V6) {
-						ovh = SCTP_MED_OVERHEAD;
-					} else {
-						ovh = SCTP_MED_V4_OVERHEAD;
-					}
-
 					paddrp->spp_hbinterval = net->heart_beat_delay;
 					paddrp->spp_pathmaxrxt = net->failure_threshold;
-					paddrp->spp_pathmtu = net->mtu - ovh;
+					paddrp->spp_pathmtu = net->mtu;
+					switch (net->ro._l_addr.sa.sa_family) {
+#ifdef INET
+					case AF_INET:
+						paddrp->spp_pathmtu -= SCTP_MIN_V4_OVERHEAD;
+						break;
+#endif
+#ifdef INET6
+					case AF_INET6:
+						paddrp->spp_pathmtu -= SCTP_MIN_V4_OVERHEAD;
+						break;
+#endif
+					default:
+						break;
+					}
 					/* get flags for HB */
 					if (net->dest_state & SCTP_ADDR_NOHB) {
 						paddrp->spp_flags |= SPP_HB_DISABLE;
@@ -2479,7 +2485,7 @@ flags_out:
 					 * value
 					 */
 					paddrp->spp_pathmaxrxt = stcb->asoc.def_net_failure;
-					paddrp->spp_pathmtu = sctp_get_frag_point(stcb, &stcb->asoc);
+					paddrp->spp_pathmtu = 0;
 					if (stcb->asoc.default_dscp & 0x01) {
 						paddrp->spp_dscp = stcb->asoc.default_dscp & 0xfc;
 						paddrp->spp_flags |= SPP_DSCP;
@@ -2615,6 +2621,20 @@ flags_out:
 				paddri->spinfo_rto = net->RTO;
 				paddri->spinfo_assoc_id = sctp_get_associd(stcb);
 				paddri->spinfo_mtu = net->mtu;
+				switch (addr->sa_family) {
+#if defined(INET)
+				case AF_INET:
+					paddri->spinfo_mtu -= SCTP_MIN_V4_OVERHEAD;
+					break;
+#endif
+#if defined(INET6)
+				case AF_INET6:
+					paddri->spinfo_mtu -= SCTP_MIN_OVERHEAD;
+					break;
+#endif
+				default:
+					break;
+				}
 				SCTP_TCB_UNLOCK(stcb);
 				*optsize = sizeof(struct sctp_paddrinfo);
 			} else {
@@ -2691,6 +2711,20 @@ flags_out:
 			sstat->sstat_primary.spinfo_srtt = net->lastsa >> SCTP_RTT_SHIFT;
 			sstat->sstat_primary.spinfo_rto = net->RTO;
 			sstat->sstat_primary.spinfo_mtu = net->mtu;
+			switch (stcb->asoc.primary_destination->ro._l_addr.sa.sa_family) {
+#if defined(INET)
+			case AF_INET:
+				sstat->sstat_primary.spinfo_mtu -= SCTP_MIN_V4_OVERHEAD;
+				break;
+#endif
+#if defined(INET6)
+			case AF_INET6:
+				sstat->sstat_primary.spinfo_mtu -= SCTP_MIN_OVERHEAD;
+				break;
+#endif
+			default:
+				break;
+			}
 			sstat->sstat_primary.spinfo_assoc_id = sctp_get_associd(stcb);
 			SCTP_TCB_UNLOCK(stcb);
 			*optsize = sizeof(struct sctp_status);
@@ -5188,19 +5222,6 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 			}
 			if (stcb != NULL) {
 				/************************TCB SPECIFIC SET ******************/
-				/*
-				 * do we change the timer for HB, we run
-				 * only one?
-				 */
-				int ovh = 0;
-
-				if (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_BOUND_V6) {
-					ovh = SCTP_MED_OVERHEAD;
-				} else {
-					ovh = SCTP_MED_V4_OVERHEAD;
-				}
-
-				/* network sets ? */
 				if (net != NULL) {
 					/************************NET SPECIFIC SET ******************/
 					if (paddrp->spp_flags & SPP_HB_DISABLE) {
@@ -5234,7 +5255,21 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 							    SCTP_FROM_SCTP_USRREQ + SCTP_LOC_11);
 						}
 						net->dest_state |= SCTP_ADDR_NO_PMTUD;
-						net->mtu = paddrp->spp_pathmtu + ovh;
+						net->mtu = paddrp->spp_pathmtu;
+						switch (net->ro._l_addr.sa.sa_family) {
+#ifdef INET
+						case AF_INET:
+							net->mtu += SCTP_MIN_V4_OVERHEAD;
+							break;
+#endif
+#ifdef INET6
+						case AF_INET6:
+							net->mtu += SCTP_MIN_OVERHEAD;
+							break;
+#endif
+						default:
+							break;
+						}
 						if (net->mtu < stcb->asoc.smallest_mtu) {
 							sctp_pathmtu_adjustment(stcb, net->mtu);
 						}
@@ -5362,7 +5397,21 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 								    SCTP_FROM_SCTP_USRREQ + SCTP_LOC_16);
 							}
 							net->dest_state |= SCTP_ADDR_NO_PMTUD;
-							net->mtu = paddrp->spp_pathmtu + ovh;
+							net->mtu = paddrp->spp_pathmtu;
+							switch (net->ro._l_addr.sa.sa_family) {
+#ifdef INET
+							case AF_INET:
+								net->mtu += SCTP_MIN_V4_OVERHEAD;
+								break;
+#endif
+#ifdef INET6
+							case AF_INET6:
+								net->mtu += SCTP_MIN_OVERHEAD;
+								break;
+#endif
+							default:
+								break;
+							}
 							if (net->mtu < stcb->asoc.smallest_mtu) {
 								sctp_pathmtu_adjustment(stcb, net->mtu);
 							}