pimd: implement IGMP group/source count limit

For groups we can just look at the length of the list, for sources we
need to count them on a per-interface level.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

8 files changed, 155 insertions, 0 deletions

diff --git a/pimd/pim_cmd.c b/pimd/pim_cmd.c
index a1ad261869..fa9c6f9537 100644
--- a/pimd/pim_cmd.c
+++ b/pimd/pim_cmd.c
@@ -5656,6 +5656,43 @@ DEFUN (interface_no_ip_igmp_last_member_query_interval,
 	return gm_process_no_last_member_query_interval_cmd(vty);
 }
 
+DEFPY_YANG(interface_ip_igmp_limits,
+           interface_ip_igmp_limits_cmd,
+           "[no] ip igmp <max-sources$do_src (0-4294967295)$val"
+	     "|max-groups$do_grp (0-4294967295)$val>",
+           NO_STR
+           IP_STR
+           IFACE_IGMP_STR
+           "Limit number of IGMPv3 sources to track\n"
+           "Permitted number of sources\n"
+           "Limit number of IGMP 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_ip_igmp_limits,
+           no_interface_ip_igmp_limits_cmd,
+           "no ip igmp <max-sources$do_src|max-groups$do_grp>",
+           NO_STR
+           IP_STR
+           IFACE_IGMP_STR
+           "Limit number of IGMPv3 sources to track\n"
+           "Limit number of IGMP group memberships to track\n")
+
 DEFUN (interface_ip_pim_drprio,
        interface_ip_pim_drprio_cmd,
        "ip pim drpriority (0-4294967295)",
@@ -9101,6 +9138,8 @@ void pim_cmd_init(void)
 	install_element(INTERFACE_NODE,
 			&interface_no_ip_igmp_last_member_query_interval_cmd);
 	install_element(INTERFACE_NODE, &interface_ip_igmp_proxy_cmd);
+	install_element(INTERFACE_NODE, &interface_ip_igmp_limits_cmd);
+	install_element(INTERFACE_NODE, &no_interface_ip_igmp_limits_cmd);
 	install_element(INTERFACE_NODE, &interface_ip_pim_activeactive_cmd);
 	install_element(INTERFACE_NODE, &interface_ip_pim_ssm_cmd);
 	install_element(INTERFACE_NODE, &interface_no_ip_pim_ssm_cmd);
diff --git a/pimd/pim_iface.h b/pimd/pim_iface.h
index 90a81a21d0..0a7993fd27 100644
--- a/pimd/pim_iface.h
+++ b/pimd/pim_iface.h
@@ -105,6 +105,8 @@ struct pim_interface {
 
 	struct gm_if *mld;
 
+	uint32_t gm_source_limit, gm_group_limit;
+
 	int pim_sock_fd;		/* PIM socket file descriptor */
 	struct event *t_pim_sock_read;	/* thread for reading PIM socket */
 	int64_t pim_sock_creation;      /* timestamp of PIM socket creation */
diff --git a/pimd/pim_igmp.c b/pimd/pim_igmp.c
index 12f424248f..fa915719dd 100644
--- a/pimd/pim_igmp.c
+++ b/pimd/pim_igmp.c
@@ -1126,6 +1126,9 @@ 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;
 
@@ -1416,6 +1419,14 @@ struct gm_group *igmp_add_group_by_addr(struct gm_sock *igmp,
 				__func__, &group_addr);
 		return NULL;
 	}
+
+	if (listcount(pim_ifp->gm_group_list) >= pim_ifp->gm_group_limit) {
+		if (PIM_DEBUG_GM_TRACE)
+			zlog_debug("interface %s has reached group limit (%u), refusing to add group %pI4",
+				   igmp->interface->name, pim_ifp->gm_group_limit, &group_addr);
+		return NULL;
+	}
+
 	/*
 	  Non-existant group is created as INCLUDE {empty}:
 
diff --git a/pimd/pim_igmpv3.c b/pimd/pim_igmpv3.c
index 7348d8130f..7cb168dc5d 100644
--- a/pimd/pim_igmpv3.c
+++ b/pimd/pim_igmpv3.c
@@ -423,6 +423,7 @@ struct gm_source *igmp_find_source_by_addr(struct gm_group *group,
 struct gm_source *igmp_get_source_by_addr(struct gm_group *group,
 					  struct in_addr src_addr, bool *new)
 {
+	const struct pim_interface *pim_interface = group->interface->info;
 	struct gm_source *src;
 
 	if (new)
@@ -432,6 +433,14 @@ struct gm_source *igmp_get_source_by_addr(struct gm_group *group,
 	if (src)
 		return src;
 
+	if (listcount(group->group_source_list) >= pim_interface->gm_source_limit) {
+		if (PIM_DEBUG_GM_TRACE)
+			zlog_debug("interface %s has reached source limit (%u), refusing to add source %pI4 (group %pI4)",
+				   group->interface->name, pim_interface->gm_source_limit,
+				   &src_addr, &group->group_addr);
+		return NULL;
+	}
+
 	if (PIM_DEBUG_GM_TRACE) {
 		char group_str[INET_ADDRSTRLEN];
 		char source_str[INET_ADDRSTRLEN];
diff --git a/pimd/pim_nb.c b/pimd/pim_nb.c
index ea9ce3cecb..62c5d531d9 100644
--- a/pimd/pim_nb.c
+++ b/pimd/pim_nb.c
@@ -725,6 +725,18 @@ const struct frr_yang_module_info frr_gmp_info = {
 				.destroy = lib_interface_gmp_address_family_join_group_destroy,
 			}
 		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-gmp:gmp/address-family/max-sources",
+			.cbs = {
+				.modify = lib_interface_gm_max_sources_modify,
+			}
+		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-gmp:gmp/address-family/max-groups",
+			.cbs = {
+				.modify = lib_interface_gm_max_groups_modify,
+			}
+		},
 				{
 			.xpath = "/frr-interface:lib/interface/frr-gmp:gmp/address-family/proxy",
 			.cbs = {
diff --git a/pimd/pim_nb.h b/pimd/pim_nb.h
index a15c6e6d9f..1656313fc2 100644
--- a/pimd/pim_nb.h
+++ b/pimd/pim_nb.h
@@ -287,6 +287,8 @@ int lib_interface_gmp_address_family_static_group_create(
 		struct nb_cb_create_args *args);
 int lib_interface_gmp_address_family_static_group_destroy(
 		struct nb_cb_destroy_args *args);
+int lib_interface_gm_max_sources_modify(struct nb_cb_modify_args *args);
+int lib_interface_gm_max_groups_modify(struct nb_cb_modify_args *args);
 
 /*
  * Callback registered with routing_nb lib to validate only
diff --git a/pimd/pim_nb_config.c b/pimd/pim_nb_config.c
index 5203f78b92..c926696610 100644
--- a/pimd/pim_nb_config.c
+++ b/pimd/pim_nb_config.c
@@ -4397,6 +4397,72 @@ int lib_interface_gmp_address_family_last_member_query_interval_modify(
 }
 
 /*
+ * XPath: /frr-interface:lib/interface/frr-gmp:gmp/address-family/max-groups
+ */
+int lib_interface_gm_max_groups_modify(struct nb_cb_modify_args *args)
+{
+	struct interface *ifp;
+	struct pim_interface *pim_ifp;
+	const char *ifp_name;
+	const struct lyd_node *if_dnode;
+
+	switch (args->event) {
+	case NB_EV_VALIDATE:
+		if_dnode = yang_dnode_get_parent(args->dnode, "interface");
+		if (!is_pim_interface(if_dnode)) {
+			ifp_name = yang_dnode_get_string(if_dnode, "name");
+			snprintf(args->errmsg, args->errmsg_len,
+				 "multicast not enabled on interface %s", ifp_name);
+			return NB_ERR_VALIDATION;
+		}
+		break;
+	case NB_EV_PREPARE:
+	case NB_EV_ABORT:
+		break;
+	case NB_EV_APPLY:
+		ifp = nb_running_get_entry(args->dnode, NULL, true);
+		pim_ifp = ifp->info;
+		pim_ifp->gm_group_limit = yang_dnode_get_uint32(args->dnode, NULL);
+		break;
+	}
+
+	return NB_OK;
+}
+
+/*
+ * XPath: /frr-interface:lib/interface/frr-gmp:gmp/address-family/max-sources
+ */
+int lib_interface_gm_max_sources_modify(struct nb_cb_modify_args *args)
+{
+	struct interface *ifp;
+	struct pim_interface *pim_ifp;
+	const char *ifp_name;
+	const struct lyd_node *if_dnode;
+
+	switch (args->event) {
+	case NB_EV_VALIDATE:
+		if_dnode = yang_dnode_get_parent(args->dnode, "interface");
+		if (!is_pim_interface(if_dnode)) {
+			ifp_name = yang_dnode_get_string(if_dnode, "name");
+			snprintf(args->errmsg, args->errmsg_len,
+				 "multicast not enabled on interface %s", ifp_name);
+			return NB_ERR_VALIDATION;
+		}
+		break;
+	case NB_EV_PREPARE:
+	case NB_EV_ABORT:
+		break;
+	case NB_EV_APPLY:
+		ifp = nb_running_get_entry(args->dnode, NULL, true);
+		pim_ifp = ifp->info;
+		pim_ifp->gm_source_limit = yang_dnode_get_uint32(args->dnode, NULL);
+		break;
+	}
+
+	return NB_OK;
+}
+
+/*
  * XPath: /frr-interface:lib/interface/frr-gmp:gmp/address-family/robustness-variable
  */
 int lib_interface_gmp_address_family_robustness_variable_modify(
diff --git a/pimd/pim_vty.c b/pimd/pim_vty.c
index a972a38c72..9456a40ffa 100644
--- a/pimd/pim_vty.c
+++ b/pimd/pim_vty.c
@@ -457,6 +457,20 @@ int pim_config_write(struct vty *vty, int writes, struct interface *ifp,
 		++writes;
 	}
 
+	/* IF ip igmp 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 (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);
+		++writes;
+	}
+
 	/* IF ip pim drpriority */
 	if (pim_ifp->pim_dr_priority != PIM_DEFAULT_DR_PRIORITY) {
 		vty_out(vty, " " PIM_AF_NAME " pim drpriority %u\n",