pim6d: implement MLD source/group limits

Let user configure a source/group limit for MLD protocol.

Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>

pimd/pim6_cmd.c

@@ -1612,6 +1612,43 @@ DEFPY (interface_no_ipv6_mld_version,
 				    "frr-routing:ipv6");
 }
 
+DEFPY_YANG(interface_ipv6_mld_limits,
+           interface_ipv6_mld_limits_cmd,
+           "[no] ipv6 mld <max-sources$do_src (0-4294967295)$val"
+	     "|max-groups$do_grp (0-4294967295)$val>",
+           NO_STR
+           IPV6_STR
+           IFACE_MLD_STR
+           "Limit number of MLDv2 sources to track\n"
+           "Permitted number of sources\n"
+           "Limit number of MLD group memberships to track\n"
+           "Permitted number of groups\n")
+{
+	const char *xpath;
+
+	assert(do_src || do_grp);
+	if (do_src)
+		xpath = "./max-sources";
+	else
+		xpath = "./max-groups";
+
+	if (no)
+		nb_cli_enqueue_change(vty, xpath, NB_OP_DESTROY, NULL);
+	else
+		nb_cli_enqueue_change(vty, xpath, NB_OP_MODIFY, val_str);
+
+	return nb_cli_apply_changes(vty, FRR_GMP_INTERFACE_XPATH, FRR_PIM_AF_XPATH_VAL);
+}
+
+ALIAS_YANG(interface_ipv6_mld_limits,
+           no_interface_ipv6_mld_limits_cmd,
+           "no ipv6 mld <max-sources$do_src|max-groups$do_grp>",
+           NO_STR
+           IPV6_STR
+           IFACE_MLD_STR
+           "Limit number of MLDv2 sources to track\n"
+           "Limit number of MLD group memberships to track\n")
+
 DEFPY (interface_ipv6_mld_query_interval,
        interface_ipv6_mld_query_interval_cmd,
        "ipv6 mld query-interval (1-65535)$q_interval",
@@ -2865,6 +2902,9 @@ void pim_cmd_init(void)
 	install_element(INTERFACE_NODE, &interface_no_ipv6_pim_boundary_oil_cmd);
 	install_element(INTERFACE_NODE, &interface_ipv6_mroute_cmd);
 	install_element(INTERFACE_NODE, &interface_no_ipv6_mroute_cmd);
+	install_element(INTERFACE_NODE, &interface_ipv6_mld_limits_cmd);
+	install_element(INTERFACE_NODE, &no_interface_ipv6_mld_limits_cmd);
+
 	/* Install BSM command */
 	install_element(INTERFACE_NODE, &ipv6_pim_bsm_cmd);
 	install_element(INTERFACE_NODE, &no_ipv6_pim_bsm_cmd);

pimd/pim6_mld.c

@@ -190,11 +190,26 @@ static struct gm_sg *gm_sg_find(struct gm_if *gm_ifp, pim_addr grp,
 	return gm_sgs_find(gm_ifp->sgs, &ref);
 }
 
+static bool gm_sg_has_group(struct gm_sgs_head *sgs, const pim_addr group)
+{
+	struct gm_sg *sg;
+
+	frr_each (gm_sgs, sgs, sg)
+		if (pim_addr_cmp(sg->sgaddr.grp, group) == 0)
+			return true;
+
+	return false;
+}
+
 static struct gm_sg *gm_sg_make(struct gm_if *gm_ifp, pim_addr grp,
 				pim_addr src)
 {
 	struct gm_sg *ret, *prev;
 
+	/* Count all unique group members. */
+	if (!gm_sg_has_group(gm_ifp->sgs, grp))
+		gm_ifp->groups_count++;
+
 	ret = XCALLOC(MTYPE_GM_SG, sizeof(*ret));
 	ret->sgaddr.grp = grp;
 	ret->sgaddr.src = src;
@@ -212,6 +227,47 @@ static struct gm_sg *gm_sg_make(struct gm_if *gm_ifp, pim_addr grp,
 	return ret;
 }
 
+static size_t gm_sg_source_count(struct gm_sgs_head *sgs, const pim_addr group)
+{
+	struct gm_sg *sg;
+	size_t source_count;
+
+	source_count = 0;
+	frr_each (gm_sgs, sgs, sg)
+		if (pim_addr_cmp(sg->sgaddr.grp, group) == 0)
+			source_count++;
+
+	return source_count;
+}
+
+static bool gm_sg_limit_reached(struct gm_if *gm_if, const pim_addr source, const pim_addr group)
+{
+	const struct pim_interface *pim_interface = gm_if->ifp->info;
+
+	if (!gm_sg_has_group(gm_if->sgs, group)) {
+		if (gm_if->groups_count >= pim_interface->gm_group_limit) {
+			if (PIM_DEBUG_GM_TRACE)
+				zlog_debug("interface %s has reached group limit (%u), refusing to add group %pPA",
+					   gm_if->ifp->name, pim_interface->gm_group_limit, &group);
+
+			return true;
+		}
+
+		return false;
+	}
+
+	if (gm_sg_source_count(gm_if->sgs, group) >= pim_interface->gm_source_limit) {
+		if (PIM_DEBUG_GM_TRACE) {
+			zlog_debug("interface %s has reached source limit (%u), refusing to add source %pPA (group %pPA)",
+				   gm_if->ifp->name, pim_interface->gm_source_limit, &source,
+				   &group);
+		}
+		return true;
+	}
+
+	return false;
+}
+
 /*
  * interface -> packets, sorted by expiry (because add_tail insert order)
  */
@@ -471,6 +527,11 @@ static void gm_sg_update(struct gm_sg *sg, bool has_expired)
 			zlog_debug(log_sg(sg, "dropping"));
 
 		gm_sgs_del(gm_ifp->sgs, sg);
+
+		/* Decrement unique group members counter. */
+		if (!gm_sg_has_group(gm_ifp->sgs, sg->sgaddr.grp))
+			gm_ifp->groups_count--;
+
 		gm_sg_free(sg);
 	}
 }
@@ -634,8 +695,12 @@ static void gm_handle_v2_pass1(struct gm_packet_state *pkt,
 	case MLD_RECTYPE_CHANGE_TO_EXCLUDE:
 		/* this always replaces or creates state */
 		is_excl = true;
-		if (!grp)
+		if (!grp) {
+			if (gm_sg_limit_reached(pkt->iface, PIMADDR_ANY, rechdr->grp))
+				return;
+
 			grp = gm_sg_make(pkt->iface, rechdr->grp, PIMADDR_ANY);
+		}
 
 		item = gm_packet_sg_setup(pkt, grp, is_excl, false);
 		item->n_exclude = n_src;
@@ -700,9 +765,13 @@ static void gm_handle_v2_pass1(struct gm_packet_state *pkt,
 		struct gm_sg *sg;
 
 		sg = gm_sg_find(pkt->iface, rechdr->grp, rechdr->srcs[j]);
-		if (!sg)
+		if (!sg) {
+			if (gm_sg_limit_reached(pkt->iface, rechdr->srcs[j], rechdr->grp))
+				return;
+
 			sg = gm_sg_make(pkt->iface, rechdr->grp,
 					rechdr->srcs[j]);
+		}
 
 		gm_packet_sg_setup(pkt, sg, is_excl, true);
 	}
@@ -952,6 +1021,10 @@ static void gm_handle_v1_report(struct gm_if *gm_ifp,
 
 	hdr = (struct mld_v1_pkt *)data;
 
+	if (!gm_sg_has_group(gm_ifp->sgs, hdr->grp) &&
+	    gm_sg_limit_reached(gm_ifp, PIMADDR_ANY, hdr->grp))
+		return;
+
 	max_entries = 1;
 	pkt = XCALLOC(MTYPE_GM_STATE,
 		      offsetof(struct gm_packet_state, items[max_entries]));
@@ -1255,6 +1328,9 @@ static void gm_handle_q_groupsrc(struct gm_if *gm_ifp,
 
 	for (i = 0; i < n_src; i++) {
 		sg = gm_sg_find(gm_ifp, grp, srcs[i]);
+		if (sg == NULL)
+			continue;
+
 		GM_UPDATE_SG_STATE(sg);
 		gm_sg_timer_start(gm_ifp, sg, timers->expire_wait);
 	}

pimd/pim6_mld.h

@@ -350,6 +350,8 @@ struct gm_if {
 	struct gm_subscribers_head subscribers[1];
 	struct gm_packet_expires_head expires[1];
 
+	size_t groups_count;
+
 	struct timeval started;
 	struct gm_if_stats stats;
 };

pimd/pim_iface.c

@@ -128,6 +128,8 @@ struct pim_interface *pim_if_new(struct interface *ifp, bool gm, bool pim,
 	pim_ifp->gm_specific_query_max_response_time_dsec =
 		GM_SPECIFIC_QUERY_MAX_RESPONSE_TIME_DSEC;
 	pim_ifp->gm_last_member_query_count = GM_DEFAULT_ROBUSTNESS_VARIABLE;
+	pim_ifp->gm_group_limit = UINT32_MAX;
+	pim_ifp->gm_source_limit = UINT32_MAX;
 
 	/* BSM config on interface: true by default */
 	pim_ifp->bsm_enable = true;

pimd/pim_igmp.c

@@ -1126,9 +1126,6 @@ void pim_igmp_if_init(struct pim_interface *pim_ifp, struct interface *ifp)
 {
 	char hash_name[64];
 
-	pim_ifp->gm_group_limit = UINT32_MAX;
-	pim_ifp->gm_source_limit = UINT32_MAX;
-
 	pim_ifp->gm_socket_list = list_new();
 	pim_ifp->gm_socket_list->del = (void (*)(void *))igmp_sock_free;
 

pimd/pim_vty.c

@@ -457,14 +457,14 @@ int pim_config_write(struct vty *vty, int writes, struct interface *ifp,
 		++writes;
 	}
 
-	/* IF ip igmp max-sources */
+	/* IF igmp/mld max-sources */
 	if (pim_ifp->gm_source_limit != UINT32_MAX) {
 		vty_out(vty, " " PIM_AF_NAME " " GM_AF_DBG " max-sources %u\n",
 			pim_ifp->gm_source_limit);
 		++writes;
 	}
 
-	/* IF ip igmp max-groups */
+	/* IF igmp/mld max-groups */
 	if (pim_ifp->gm_group_limit != UINT32_MAX) {
 		vty_out(vty, " " PIM_AF_NAME " " GM_AF_DBG " max-groups %u\n",
 			pim_ifp->gm_group_limit);