More prerequisites without actually sending probes

usrsctplib/netinet/sctp_input.c

@@ -935,6 +935,10 @@ sctp_start_net_timers(struct sctp_tcb *stcb)
 		sctp_timer_start(SCTP_TIMER_TYPE_HEARTBEAT, stcb->sctp_ep, stcb, net);
 		if ((net->dest_state & SCTP_ADDR_UNCONFIRMED) &&
 		    (cnt_hb_sent < SCTP_BASE_SYSCTL(sctp_hb_maxburst))) {
+		    if (stcb->asoc.plpmtud_supported) {
+				net->probing_state = SCTP_PROBE_NONE;
+				net->probe_mtu = 0;
+			}
 			sctp_send_hb(stcb, net, SCTP_SO_NOT_LOCKED);
 			cnt_hb_sent++;
 		}

usrsctplib/netinet/sctp_output.c

@@ -4487,9 +4487,11 @@ sctp_lowlevel_chunk_output(struct sctp_inpcb *inp,
 					if ((stcb != NULL) && (stcb->asoc.smallest_mtu > mtu)) {
 						sctp_mtu_size_reset(inp, &stcb->asoc, mtu);
 					}
-					net->mtu = mtu;
 					net->got_max = 1;
-					sctp_pathmtu_adjustment(stcb, net->mtu, net);
+					if (!stcb->sctp_ep->plpmtud_supported) {
+						net->mtu = mtu;
+						sctp_pathmtu_adjustment(stcb, net->mtu, net);
+					}
 				}
 #else
 				mtu = SCTP_GATHER_MTU_FROM_ROUTE(net->ro._s_addr, &net->ro._l_addr.sa, ro->ro_rt);
@@ -4958,27 +4960,39 @@ sctp_lowlevel_chunk_output(struct sctp_inpcb *inp,
 
 #if defined(__Userspace__)
 				mtu = sctp_get_mtu_from_addr(inp, (struct sockaddr *)&(net->ro._s_addr->address.sin));
-				if (mtu > 0 && (mtu < net->mtu || !net->got_max)) {
-					if (net->port) {
-						mtu -= sizeof(struct udphdr);
+				if (!stcb->sctp_ep->plpmtud_supported) {
+					if (mtu > 0 && (mtu < net->mtu || !net->got_max)) {
+						if (net->port) {
+							mtu -= sizeof(struct udphdr);
+						}
+						if ((stcb != NULL) && (stcb->asoc.smallest_mtu > mtu)) {
+							sctp_mtu_size_reset(inp, &stcb->asoc, mtu);
+						}
+						net->mtu = mtu;
+						net->got_max = 1;
+						sctp_pathmtu_adjustment(stcb, net->mtu, net);
 					}
-					if ((stcb != NULL) && (stcb->asoc.smallest_mtu > mtu)) {
-						sctp_mtu_size_reset(inp, &stcb->asoc, mtu);
+				} else {
+					if (net->port) {
+						net->mtu -= sizeof(struct udphdr);
 					}
-					net->mtu = mtu;
-					net->got_max = 1;
-					sctp_pathmtu_adjustment(stcb, net->mtu, net);
 				}
 #else
 				mtu = SCTP_GATHER_MTU_FROM_ROUTE(net->ro._s_addr, &net->ro._l_addr.sa, ro->ro_rt);
 				if (mtu > 0) {
-					if (net->port) {
-						mtu -= sizeof(struct udphdr);
-					}
-					if ((stcb != NULL) && (stcb->asoc.smallest_mtu > mtu)) {
-						sctp_mtu_size_reset(inp, &stcb->asoc, mtu);
+					if (!stcb->sctp_ep->plpmtud_supported) {
+						if (net->port) {
+							mtu -= sizeof(struct udphdr);
+						}
+						if ((stcb != NULL) && (stcb->asoc.smallest_mtu > mtu)) {
+							sctp_mtu_size_reset(inp, &stcb->asoc, mtu);
+						}
+						net->mtu = mtu;
+					} else {
+						if (net->port) {
+							net->mtu -= sizeof(struct udphdr);
+						}
 					}
-					net->mtu = mtu;
 					net->got_max = 1;
 				}
 #endif

usrsctplib/netinet/sctp_pcb.c

@@ -4618,6 +4618,12 @@ sctp_add_remote_addr(struct sctp_tcb *stcb, struct sockaddr *newaddr,
 	net->RTO_measured = 0;
 	stcb->asoc.numnets++;
 	net->ref_count = 1;
+	if (stcb->asoc.plpmtud_supported) {
+		net->probe_mtu = 0;
+		net->mtu_probing = 0;
+		net->probing_state = SCTP_PROBE_NONE;
+		net->got_max = 0;
+	}
 	net->cwr_window_tsn = net->last_cwr_tsn = stcb->asoc.sending_seq - 1;
 	net->port = port;
 	net->dscp = stcb->asoc.default_dscp;
@@ -4727,6 +4733,12 @@ sctp_add_remote_addr(struct sctp_tcb *stcb, struct sockaddr *newaddr,
 				/* Start things off to match mtu of interface please. */
 				SCTP_SET_MTU_OF_ROUTE(&net->ro._l_addr.sa,
 				                      net->ro.ro_rt, net->mtu);
+			} else if (stcb->asoc.plpmtud_supported) {
+				net->mtu = min(rmtu, SCTP_DEFAULT_MTU);
+			}
+			if (stcb->asoc.plpmtud_supported) {
+				net->max_mtu = max(net->mtu, rmtu);
+				net->max_mtu -= net->max_mtu % 4;
 			}
 			net->got_max = 1;
 		}