gprs_ns2_sns: implement outbound SNS DEL procedures

When removing a bind the remote side needs to be
informed via the SNS DELETE procedure.

Related: OS#5036
Change-Id: I53cd54dfd262c70c425c3f13dad3b29526daa523

1 files changed, 95 insertions, 9 deletions

diff --git a/src/gb/gprs_ns2_sns.c b/src/gb/gprs_ns2_sns.c
index 0cb24c56..3eff0f3a 100644
--- a/src/gb/gprs_ns2_sns.c
+++ b/src/gb/gprs_ns2_sns.c
@@ -150,6 +150,9 @@ struct ns2_sns_state {
 	/* prevent recursive reselection */
 	bool reselection_running;
 
+	/* protection against recursive free() */
+	bool block_no_nsvc_events;
+
 	/* The current initial SNS endpoints.
 	 * The initial connection will be moved into the NSE
 	 * if configured via SNS. Otherwise it will be removed
@@ -323,7 +326,8 @@ void ns2_sns_replace_nsvc(struct gprs_ns2_vc *nsvc)
 		}
 	}
 
-	osmo_fsm_inst_dispatch(fi, NS2_SNS_EV_REQ_NO_NSVC, NULL);
+	if (gss->block_no_nsvc_events)
+		osmo_fsm_inst_dispatch(fi, NS2_SNS_EV_REQ_NO_NSVC, NULL);
 }
 
 static void ns2_clear_elems(struct ns2_sns_elems *elems)
@@ -595,6 +599,32 @@ static int update_ip6_elem(struct ns2_sns_state *gss, struct ns2_sns_elems *elem
 	return -1;
 }
 
+static int remove_bind_elem(struct ns2_sns_state *gss, struct ns2_sns_elems *elems, struct ns2_sns_bind *sbind)
+{
+	struct gprs_ns_ie_ip4_elem ip4;
+	struct gprs_ns_ie_ip6_elem ip6;
+	const struct osmo_sockaddr *saddr = gprs_ns2_ip_bind_sockaddr(sbind->bind);
+
+	switch (saddr->u.sa.sa_family) {
+	case AF_INET:
+		ip4.ip_addr = saddr->u.sin.sin_addr.s_addr;
+		ip4.udp_port = saddr->u.sin.sin_port;
+		ip4.sig_weight = sbind->bind->sns_sig_weight;
+		ip4.data_weight = sbind->bind->sns_data_weight;
+		return remove_ip4_elem(gss, elems, &ip4);
+	case AF_INET6:
+		memcpy(&ip6.ip_addr, &saddr->u.sin6.sin6_addr, sizeof(struct in6_addr));
+		ip6.udp_port = saddr->u.sin.sin_port;
+		ip6.sig_weight = sbind->bind->sns_sig_weight;
+		ip6.data_weight = sbind->bind->sns_data_weight;
+		return remove_ip6_elem(gss, elems, &ip6);
+	default:
+		return -1;
+	}
+
+	return -1;
+}
+
 static int do_sns_change_weight(struct osmo_fsm_inst *fi, const struct gprs_ns_ie_ip4_elem *ip4, const struct gprs_ns_ie_ip6_elem *ip6)
 {
 	struct ns2_sns_state *gss = (struct ns2_sns_state *) fi->priv;
@@ -1487,6 +1517,12 @@ static void ns2_sns_st_local_procedure_onenter(struct osmo_fsm_inst *fi, uint32_
 		else
 			ns2_tx_sns_change_weight(gss->sns_nsvc, gss->current_procedure->trans_id, NULL, 0, &gss->current_procedure->ip6, 1);
 		break;
+	case SNS_PROC_DEL:
+		if (gss->family == AF_INET)
+			ns2_tx_sns_del(gss->sns_nsvc, gss->current_procedure->trans_id, &gss->current_procedure->ip4, 1, NULL, 0);
+		else
+			ns2_tx_sns_del(gss->sns_nsvc, gss->current_procedure->trans_id, NULL, 0, &gss->current_procedure->ip6, 1);
+		break;
 	default:
 		break;
 	}
@@ -1599,8 +1635,11 @@ static void ns2_sns_st_local_procedure(struct osmo_fsm_inst *fi, uint32_t event,
 				add_ip6_elem(gss, &gss->local, &gss->current_procedure->ip6);
 				break;
 			}
-			create_nsvc_for_new_sbind(gss, gss->current_procedure->sbind);
-			gprs_ns2_start_alive_all_nsvcs(nse);
+			/* the sbind can be NULL if the bind has been released by del_bind */
+			if (gss->current_procedure->sbind) {
+				create_nsvc_for_new_sbind(gss, gss->current_procedure->sbind);
+				gprs_ns2_start_alive_all_nsvcs(nse);
+			}
 			break;
 		case SNS_PROC_CHANGE_WEIGHT:
 			switch (gss->family) {
@@ -1633,6 +1672,16 @@ static void ns2_sns_st_local_procedure(struct osmo_fsm_inst *fi, uint32_t event,
 				OSMO_ASSERT(0);
 			}
 			break;
+		case SNS_PROC_DEL:
+			switch (gss->family) {
+			case AF_INET:
+				remove_ip4_elem(gss, &gss->local, &gss->current_procedure->ip4);
+				break;
+			case AF_INET6:
+				remove_ip6_elem(gss, &gss->local, &gss->current_procedure->ip6);
+				break;
+			}
+			break;
 		default:
 			break;
 		}
@@ -1849,6 +1898,8 @@ static void ns2_add_procedure(struct ns2_sns_state *gss, struct ns2_sns_bind *sb
 	switch (procedure_type) {
 	case SNS_PROC_ADD:
 		break;
+	case SNS_PROC_DEL:
+		break;
 	case SNS_PROC_CHANGE_WEIGHT:
 		llist_for_each_entry(procedure, &gss->procedures, list) {
 			if (procedure->sbind == sbind && procedure->procedure == procedure_type &&
@@ -1879,8 +1930,16 @@ static void ns2_add_procedure(struct ns2_sns_state *gss, struct ns2_sns_bind *sb
 	if (!procedure)
 		return;
 
+	switch (procedure_type) {
+	case SNS_PROC_ADD:
+	case SNS_PROC_CHANGE_WEIGHT:
+		procedure->sbind = sbind;
+		break;
+	default:
+		break;
+	}
+
 	llist_add_tail(&procedure->list, &gss->procedures);
-	procedure->sbind = sbind;
 	procedure->procedure = procedure_type;
 	procedure->sig_weight = sbind->bind->sns_sig_weight;
 	procedure->data_weight = sbind->bind->sns_data_weight;
@@ -1893,7 +1952,6 @@ static void ns2_add_procedure(struct ns2_sns_state *gss, struct ns2_sns_bind *sb
 		procedure->ip4.data_weight = sbind->bind->sns_data_weight;
 		break;
 	case AF_INET6:
-
 		memcpy(&procedure->ip6.ip_addr, &saddr->u.sin6.sin6_addr, sizeof(struct in6_addr));
 		procedure->ip6.udp_port = saddr->u.sin.sin_port;
 		procedure->ip6.sig_weight = sbind->bind->sns_sig_weight;
@@ -1948,6 +2006,7 @@ static void ns2_sns_st_all_action(struct osmo_fsm_inst *fi, uint32_t event, void
 	struct ns2_sns_state *gss = (struct ns2_sns_state *) fi->priv;
 	struct ns2_sns_bind *sbind;
 	struct gprs_ns2_vc *nsvc, *nsvc2;
+	struct ns2_sns_procedure *procedure;
 
 	switch (event) {
 	case NS2_SNS_EV_REQ_ADD_BIND:
@@ -2020,25 +2079,46 @@ static void ns2_sns_st_all_action(struct osmo_fsm_inst *fi, uint32_t event, void
 		case GPRS_SNS_ST_UNCONFIGURED:
 			break;
 		case GPRS_SNS_ST_BSS_SIZE:
-			/* TODO: remove the ip4 element from the list */
 			llist_for_each_entry_safe(nsvc, nsvc2, &nse->nsvc, list) {
 				if (nsvc->bind == sbind->bind) {
 					gprs_ns2_free_nsvc(nsvc);
 				}
 			}
+			osmo_fsm_inst_dispatch(fi, NS2_SNS_EV_REQ_SELECT_ENDPOINT, NULL);
 			break;
 		case GPRS_SNS_ST_BSS_CONFIG_BSS:
 		case GPRS_SNS_ST_BSS_CONFIG_SGSN:
 		case GPRS_SNS_ST_CONFIGURED:
-			/* TODO: do an delete SNS-IP procedure */
-			/* TODO: remove the ip4 element to the list */
+		case GPRS_SNS_ST_LOCAL_PROCEDURE:
+			remove_bind_elem(gss, &gss->local_procedure, sbind);
+			if (ip46_weight_sum(&gss->local_procedure, true) == 0 ||
+					ip46_weight_sum(&gss->local_procedure, false) == 0) {
+				LOGPFSML(fi, LOGL_ERROR, "NSE %d: weight has become invalid because of removing bind %s. Resetting the configuration\n",
+					 nse->nsei, sbind->bind->name);
+				sns_failed(fi, NULL);
+				break;
+			}
+			gss->block_no_nsvc_events = true;
 			llist_for_each_entry_safe(nsvc, nsvc2, &nse->nsvc, list) {
 				if (nsvc->bind == sbind->bind) {
 					gprs_ns2_free_nsvc(nsvc);
 				}
 			}
+			gss->block_no_nsvc_events = false;
+			if (nse->sum_sig_weight == 0 || !nse->alive || !gss->alive) {
+				sns_failed(fi, "While deleting a bind the current state became invalid (no signalling weight)");
+				break;
+			}
+
+			/* ensure other procedures doesn't use the sbind */
+			llist_for_each_entry(procedure, &gss->procedures, list) {
+				if (procedure->sbind == sbind)
+					procedure->sbind = NULL;
+			}
+			ns2_add_procedure(gss, sbind, SNS_PROC_DEL);
 			break;
 		}
+
 		/* if this is the last bind, the free_nsvc() will trigger a reselection */
 		talloc_free(sbind);
 		break;
@@ -2124,7 +2204,7 @@ static void ns2_sns_st_all_action_bss(struct osmo_fsm_inst *fi, uint32_t event,
 	switch (event) {
 	case NS2_SNS_EV_REQ_NO_NSVC:
 		/* ignore reselection running */
-		if (gss->reselection_running)
+		if (gss->reselection_running || gss->block_no_nsvc_events)
 			break;
 
 		sns_failed(fi, "no remaining NSVC, resetting SNS FSM");
@@ -2134,6 +2214,9 @@ static void ns2_sns_st_all_action_bss(struct osmo_fsm_inst *fi, uint32_t event,
 		/* TODO: keep the order of binds when data == GPRS_SNS_FLAG_KEEP_SELECT_ENDPOINT_ORDER */
 		/* tear down previous state
 		 * gprs_ns2_free_nsvcs() will trigger NO_NSVC, prevent this from triggering a reselection */
+		if (gss->reselection_running || gss->block_no_nsvc_events)
+			break;
+
 		gss->reselection_running = true;
 		ns2_free_nsvcs(nse);
 		ns2_clear_elems(&gss->local);
@@ -2512,6 +2595,9 @@ void ns2_sns_notify_alive(struct gprs_ns2_nse *nse, struct gprs_ns2_vc *nsvc, bo
 	if (nse->bss_sns_fi->state != GPRS_SNS_ST_CONFIGURED && nse->bss_sns_fi->state != GPRS_SNS_ST_LOCAL_PROCEDURE)
 		return;
 
+	if (gss->block_no_nsvc_events)
+		return;
+
 	if (alive == gss->alive)
 		return;