- Change the Time Wait of vtags value to match the cookie-life

- Select a tag gains ability to optionally save new tags
  off in the timewait system.
- When looking up associations do not give back a stcb that
  is in the about-to-be-freed state, and instead continue
  looking for other candiates.
- New function to query to see if value is in time-wait.
- Timewait had a time comparison error that caused very
  few vtags to actually stay in time-wait.
- When setting tags in time-wait, we now use the time
  requested NOT a fixed constant value.
- sstat now gets the proper associd when we do the query.
- When we process an association, we expect the tag chosen
  (if we have one from a cookie) to be in time-wait. Before
  we would NOT allow the assoc up by checking if its good.
  In theory this should have caused almost all assoc not
  to come up except for the time-comparison bug above (this
  bug was hidden by the time comparison bug :-D).
- Don't save tags for nonce values in the time-wait cache
  since these are used only during cookie collisions and do
  not matter if they are unique or not.
MFC after:	1 week

sys/netinet/sctp_constants.h

@@ -1007,10 +1007,9 @@ __FBSDID("$FreeBSD$");
  */
 
 /*
- * Number of seconds of time wait, tied to MSL value (2 minutes), so 2 * MSL
- * = 4 minutes or 480 seconds.
+ * Number of seconds of time wait for a vtag.
  */
-#define SCTP_TIME_WAIT 480
+#define SCTP_TIME_WAIT 60
 
 /* This time wait is the same as the default cookie life
  * since we now enter a tag in every time we send a cookie.

sys/netinet/sctp_output.c

@@ -4955,7 +4955,7 @@ sctp_send_initiate_ack(struct sctp_inpcb *inp, struct sctp_tcb *stcb,
 		if (asoc) {
 			atomic_add_int(&asoc->refcnt, 1);
 			SCTP_TCB_UNLOCK(stcb);
-			vtag = sctp_select_a_tag(inp);
+			vtag = sctp_select_a_tag(inp, 1);
 			initackm_out->msg.init.initiate_tag = htonl(vtag);
 			/* get a TSN to use too */
 			itsn = sctp_select_initial_TSN(&inp->sctp_ep);
@@ -4963,7 +4963,7 @@ sctp_send_initiate_ack(struct sctp_inpcb *inp, struct sctp_tcb *stcb,
 			SCTP_TCB_LOCK(stcb);
 			atomic_add_int(&asoc->refcnt, -1);
 		} else {
-			vtag = sctp_select_a_tag(inp);
+			vtag = sctp_select_a_tag(inp, 1);
 			initackm_out->msg.init.initiate_tag = htonl(vtag);
 			/* get a TSN to use too */
 			initackm_out->msg.init.initial_tsn = htonl(sctp_select_initial_TSN(&inp->sctp_ep));

sys/netinet/sctp_pcb.c

@@ -928,6 +928,11 @@ sctp_tcb_special_locate(struct sctp_inpcb **inp_p, struct sockaddr *from,
 			SCTP_INP_RUNLOCK(inp);
 			continue;
 		}
+		if (stcb->asoc.state & SCTP_STATE_ABOUT_TO_BE_FREED) {
+			SCTP_TCB_UNLOCK(stcb);
+			SCTP_INP_RUNLOCK(inp);
+			continue;
+		}
 		/* Does this TCB have a matching address? */
 		TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
 
@@ -1045,11 +1050,16 @@ sctp_findassociation_ep_addr(struct sctp_inpcb **inp_p, struct sockaddr *remote,
 				goto null_return;
 			}
 			SCTP_TCB_LOCK(stcb);
+
 			if (stcb->rport != rport) {
 				/* remote port does not match. */
 				SCTP_TCB_UNLOCK(stcb);
 				goto null_return;
 			}
+			if (stcb->asoc.state & SCTP_STATE_ABOUT_TO_BE_FREED) {
+				SCTP_TCB_UNLOCK(stcb);
+				goto null_return;
+			}
 			/* now look at the list of remote addresses */
 			TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
 #ifdef INVARIANTS
@@ -1128,8 +1138,12 @@ sctp_findassociation_ep_addr(struct sctp_inpcb **inp_p, struct sockaddr *remote,
 				/* remote port does not match */
 				continue;
 			}
-			/* now look at the list of remote addresses */
 			SCTP_TCB_LOCK(stcb);
+			if (stcb->asoc.state & SCTP_STATE_ABOUT_TO_BE_FREED) {
+				SCTP_TCB_UNLOCK(stcb);
+				continue;
+			}
+			/* now look at the list of remote addresses */
 			TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
 #ifdef INVARIANTS
 				if (net == (TAILQ_NEXT(net, sctp_next))) {
@@ -1250,6 +1264,9 @@ sctp_findassociation_ep_asocid(struct sctp_inpcb *inp, sctp_assoc_t asoc_id, int
 				SCTP_INP_RUNLOCK(stcb->sctp_ep);
 				continue;
 			}
+			if (stcb->asoc.state & SCTP_STATE_ABOUT_TO_BE_FREED) {
+				continue;
+			}
 			if (want_lock) {
 				SCTP_TCB_LOCK(stcb);
 			}
@@ -1272,6 +1289,9 @@ sctp_findassociation_ep_asocid(struct sctp_inpcb *inp, sctp_assoc_t asoc_id, int
 			SCTP_INP_RUNLOCK(stcb->sctp_ep);
 			continue;
 		}
+		if (stcb->asoc.state & SCTP_STATE_ABOUT_TO_BE_FREED) {
+			continue;
+		}
 		if (want_lock) {
 			SCTP_TCB_LOCK(stcb);
 		}
@@ -1699,6 +1719,10 @@ sctp_findassoc_by_vtag(struct sockaddr *from, uint32_t vtag,
 				SCTP_TCB_UNLOCK(stcb);
 				continue;
 			}
+			if (stcb->asoc.state & SCTP_STATE_ABOUT_TO_BE_FREED) {
+				SCTP_TCB_UNLOCK(stcb);
+				continue;
+			}
 			if (skip_src_check) {
 				*netp = NULL;	/* unknown */
 				if (inp_p)
@@ -3922,6 +3946,31 @@ sctp_delete_from_timewait(uint32_t tag)
 	}
 }
 
+int
+sctp_is_in_timewait(uint32_t tag)
+{
+	struct sctpvtaghead *chain;
+	struct sctp_tagblock *twait_block;
+	int found = 0;
+	int i;
+
+	chain = &sctppcbinfo.vtag_timewait[(tag % SCTP_STACK_VTAG_HASH_SIZE)];
+	if (!SCTP_LIST_EMPTY(chain)) {
+		LIST_FOREACH(twait_block, chain, sctp_nxt_tagblock) {
+			for (i = 0; i < SCTP_NUMBER_IN_VTAG_BLOCK; i++) {
+				if (twait_block->vtag_block[i].v_tag == tag) {
+					found = 1;
+					break;
+				}
+			}
+			if (found)
+				break;
+		}
+	}
+	return (found);
+}
+
+
 void
 sctp_add_vtag_to_timewait(uint32_t tag, uint32_t time)
 {
@@ -3944,14 +3993,13 @@ sctp_add_vtag_to_timewait(uint32_t tag, uint32_t time)
 					twait_block->vtag_block[i].v_tag = tag;
 					set = 1;
 				} else if ((twait_block->vtag_block[i].v_tag) &&
-					    ((long)twait_block->vtag_block[i].tv_sec_at_expire >
-				    now.tv_sec)) {
+				    ((long)twait_block->vtag_block[i].tv_sec_at_expire < now.tv_sec)) {
 					/* Audit expires this guy */
 					twait_block->vtag_block[i].tv_sec_at_expire = 0;
 					twait_block->vtag_block[i].v_tag = 0;
 					if (set == 0) {
 						/* Reuse it for my new tag */
-						twait_block->vtag_block[0].tv_sec_at_expire = now.tv_sec + SCTP_TIME_WAIT;
+						twait_block->vtag_block[0].tv_sec_at_expire = now.tv_sec + time;
 						twait_block->vtag_block[0].v_tag = tag;
 						set = 1;
 					}
@@ -3975,8 +4023,7 @@ sctp_add_vtag_to_timewait(uint32_t tag, uint32_t time)
 		}
 		memset(twait_block, 0, sizeof(struct sctp_tagblock));
 		LIST_INSERT_HEAD(chain, twait_block, sctp_nxt_tagblock);
-		twait_block->vtag_block[0].tv_sec_at_expire = now.tv_sec +
-		    SCTP_TIME_WAIT;
+		twait_block->vtag_block[0].tv_sec_at_expire = now.tv_sec + time;
 		twait_block->vtag_block[0].v_tag = tag;
 	}
 }
@@ -5738,7 +5785,7 @@ sctp_set_primary_addr(struct sctp_tcb *stcb, struct sockaddr *sa,
 }
 
 int
-sctp_is_vtag_good(struct sctp_inpcb *inp, uint32_t tag, struct timeval *now)
+sctp_is_vtag_good(struct sctp_inpcb *inp, uint32_t tag, struct timeval *now, int save_in_twait)
 {
 	/*
 	 * This function serves two purposes. It will see if a TAG can be
@@ -5805,7 +5852,7 @@ check_time_wait:
 				if (twait_block->vtag_block[i].v_tag == 0) {
 					/* not used */
 					continue;
-				} else if ((long)twait_block->vtag_block[i].tv_sec_at_expire >
+				} else if ((long)twait_block->vtag_block[i].tv_sec_at_expire <
 				    now->tv_sec) {
 					/* Audit expires this guy */
 					twait_block->vtag_block[i].tv_sec_at_expire = 0;
@@ -5827,7 +5874,8 @@ check_time_wait:
 	 * add this tag to the assoc hash we need to purge it from
 	 * the t-wait hash.
 	 */
-	sctp_add_vtag_to_timewait(tag, TICKS_TO_SEC(inp->sctp_ep.def_cookie_life));
+	if (save_in_twait)
+		sctp_add_vtag_to_timewait(tag, TICKS_TO_SEC(inp->sctp_ep.def_cookie_life));
 	SCTP_INP_INFO_WUNLOCK();
 	return (1);
 }

sys/netinet/sctp_pcb.h

@@ -531,6 +531,8 @@ int sctp_free_assoc(struct sctp_inpcb *, struct sctp_tcb *, int, int);
 
 void sctp_delete_from_timewait(uint32_t);
 
+int sctp_is_in_timewait(uint32_t tag);
+
 void
      sctp_add_vtag_to_timewait(uint32_t, uint32_t);
 
@@ -562,7 +564,7 @@ int
 sctp_set_primary_addr(struct sctp_tcb *, struct sockaddr *,
     struct sctp_nets *);
 
-int sctp_is_vtag_good(struct sctp_inpcb *, uint32_t, struct timeval *);
+int sctp_is_vtag_good(struct sctp_inpcb *, uint32_t, struct timeval *, int);
 
 /* void sctp_drain(void); */
 

sys/netinet/sctp_usrreq.c

@@ -2266,6 +2266,7 @@ flags_out:
 			 * land.
 			 */
 			sstat->sstat_state = stcb->asoc.state;
+			sstat->sstat_assoc_id = sctp_get_associd(stcb);
 			sstat->sstat_rwnd = stcb->asoc.peers_rwnd;
 			sstat->sstat_unackdata = stcb->asoc.sent_queue_cnt;
 			/*

sys/netinet/sctputil.c

@@ -844,7 +844,7 @@ retry:
 }
 
 uint32_t
-sctp_select_a_tag(struct sctp_inpcb *inp)
+sctp_select_a_tag(struct sctp_inpcb *inp, int save_in_twait)
 {
 	u_long x, not_done;
 	struct timeval now;
@@ -857,7 +857,7 @@ sctp_select_a_tag(struct sctp_inpcb *inp)
 			/* we never use 0 */
 			continue;
 		}
-		if (sctp_is_vtag_good(inp, x, &now)) {
+		if (sctp_is_vtag_good(inp, x, &now, save_in_twait)) {
 			not_done = 0;
 		}
 	}
@@ -908,19 +908,25 @@ sctp_init_asoc(struct sctp_inpcb *m, struct sctp_tcb *stcb,
 		struct timeval now;
 
 		(void)SCTP_GETTIME_TIMEVAL(&now);
-		if (sctp_is_vtag_good(m, override_tag, &now)) {
+		if (sctp_is_in_timewait(override_tag)) {
+			/*
+			 * It must be in the time-wait hash, we put it there
+			 * when we aloc one. If not the peer is playing
+			 * games.
+			 */
 			asoc->my_vtag = override_tag;
 		} else {
 			SCTP_LTRACE_ERR_RET(NULL, stcb, NULL, SCTP_FROM_SCTPUTIL, ENOMEM);
+			panic("Huh is_in_timewait fails");
 			return (ENOMEM);
 		}
 
 	} else {
-		asoc->my_vtag = sctp_select_a_tag(m);
+		asoc->my_vtag = sctp_select_a_tag(m, 1);
 	}
 	/* Get the nonce tags */
-	asoc->my_vtag_nonce = sctp_select_a_tag(m);
-	asoc->peer_vtag_nonce = sctp_select_a_tag(m);
+	asoc->my_vtag_nonce = sctp_select_a_tag(m, 0);
+	asoc->peer_vtag_nonce = sctp_select_a_tag(m, 0);
 	asoc->vrf_id = vrf_id;
 
 	if (sctp_is_feature_on(m, SCTP_PCB_FLAGS_DONOT_HEARTBEAT))

sys/netinet/sctputil.h

@@ -77,7 +77,7 @@ struct sctp_ifa *
 
 uint32_t sctp_select_initial_TSN(struct sctp_pcb *);
 
-uint32_t sctp_select_a_tag(struct sctp_inpcb *);
+uint32_t sctp_select_a_tag(struct sctp_inpcb *, int);
 
 int sctp_init_asoc(struct sctp_inpcb *, struct sctp_tcb *, int, uint32_t, uint32_t);