Merge pull request #18111 from opensourcerouting/gmp-leave

pimd,pim6d: support IGMPv2/MLDv1 immediate leave

13 files changed, 288 insertions, 37 deletions

diff --git a/doc/user/pim.rst b/doc/user/pim.rst
index 9e4c7bb94a..0fb01a1ebb 100644
--- a/doc/user/pim.rst
+++ b/doc/user/pim.rst
@@ -424,6 +424,10 @@ is in a vrf, enter the interface command with the vrf keyword at the end.
    interfaces on this interface. Join-groups on other interfaces will
    also be proxied. The default version is v3.
 
+.. clicmd:: ip igmp immediate-leave
+
+   Immediately leaves an IGMP group when receiving a IGMPv2 Leave packet.
+
 .. clicmd:: ip igmp query-interval (1-65535)
 
    Set the IGMP query interval that PIM will use.
diff --git a/doc/user/pimv6.rst b/doc/user/pimv6.rst
index bd5430f51e..c1c2f76fc4 100644
--- a/doc/user/pimv6.rst
+++ b/doc/user/pimv6.rst
@@ -245,6 +245,10 @@ is in a vrf, enter the interface command with the vrf keyword at the end.
 
    Join multicast group or source-group on an interface.
 
+.. clicmd:: ipv6 mld immediate-leave
+
+   Immediately leaves a MLD group when receiving a MLDv1 Done packet.
+
 .. clicmd:: ipv6 mld query-interval (1-65535)
 
    Set the MLD query interval that PIM will use.
diff --git a/pimd/pim6_cmd.c b/pimd/pim6_cmd.c
index 40bd7caf7d..50357ca1d0 100644
--- a/pimd/pim6_cmd.c
+++ b/pimd/pim6_cmd.c
@@ -1649,6 +1649,19 @@ ALIAS_YANG(interface_ipv6_mld_limits,
            "Limit number of MLDv2 sources to track\n"
            "Limit number of MLD group memberships to track\n")
 
+DEFPY_YANG(interface_ipv6_mld_immediate_leave,
+           interface_ipv6_mld_immediate_leave_cmd,
+           "[no] ipv6 mld immediate-leave",
+           NO_STR
+           IPV6_STR
+           IFACE_MLD_STR
+           "Immediately drop group memberships on receiving Leave (MLDv1 only)\n")
+{
+	nb_cli_enqueue_change(vty, "./immediate-leave", NB_OP_MODIFY, no ? "false" : "true");
+
+	return nb_cli_apply_changes(vty, FRR_GMP_INTERFACE_XPATH, FRR_PIM_AF_XPATH_VAL);
+}
+
 DEFPY (interface_ipv6_mld_query_interval,
        interface_ipv6_mld_query_interval_cmd,
        "ipv6 mld query-interval (1-65535)$q_interval",
@@ -2944,6 +2957,7 @@ void pim_cmd_init(void)
 	install_element(INTERFACE_NODE, &interface_ipv6_mld_static_group_cmd);
 	install_element(INTERFACE_NODE, &interface_ipv6_mld_version_cmd);
 	install_element(INTERFACE_NODE, &interface_no_ipv6_mld_version_cmd);
+	install_element(INTERFACE_NODE, &interface_ipv6_mld_immediate_leave_cmd);
 	install_element(INTERFACE_NODE, &interface_ipv6_mld_query_interval_cmd);
 	install_element(INTERFACE_NODE,
 			&interface_no_ipv6_mld_query_interval_cmd);
diff --git a/pimd/pim6_mld.c b/pimd/pim6_mld.c
index d7e0314d3b..2546166d0a 100644
--- a/pimd/pim6_mld.c
+++ b/pimd/pim6_mld.c
@@ -448,18 +448,23 @@ static void gm_sg_update(struct gm_sg *sg, bool has_expired)
 		    desired == GM_SG_NOPRUNE_EXPIRING) {
 			struct gm_query_timers timers;
 
-			timers.qrv = gm_ifp->cur_qrv;
-			timers.max_resp_ms = gm_ifp->cur_max_resp;
-			timers.qqic_ms = gm_ifp->cur_query_intv_trig;
-			timers.fuzz = gm_ifp->cfg_timing_fuzz;
+			if (!pim_ifp->gmp_immediate_leave) {
+				timers.qrv = gm_ifp->cur_qrv;
+				timers.max_resp_ms = gm_ifp->cur_max_resp;
+				timers.qqic_ms = gm_ifp->cur_query_intv_trig;
+				timers.fuzz = gm_ifp->cfg_timing_fuzz;
+
+				gm_expiry_calc(&timers);
+			} else
+				memset(&timers.expire_wait, 0, sizeof(timers.expire_wait));
 
-			gm_expiry_calc(&timers);
 			gm_sg_timer_start(gm_ifp, sg, timers.expire_wait);
 
 			EVENT_OFF(sg->t_sg_query);
 			sg->query_sbit = false;
 			/* Trigger the specific queries only for querier. */
-			if (IPV6_ADDR_SAME(&gm_ifp->querier, &pim_ifp->ll_lowest)) {
+			if (!pim_ifp->gmp_immediate_leave &&
+			    IPV6_ADDR_SAME(&gm_ifp->querier, &pim_ifp->ll_lowest)) {
 				sg->n_query = gm_ifp->cur_lmqc;
 				gm_trigger_specific(sg);
 			}
@@ -1102,11 +1107,24 @@ static void gm_handle_v1_leave(struct gm_if *gm_ifp,
 	if (grp) {
 		old_grp = gm_packet_sg_find(grp, GM_SUB_POS, subscriber);
 		if (old_grp) {
+			const struct pim_interface *pim_ifp = gm_ifp->ifp->info;
+			struct gm_packet_sg *item;
+
 			gm_packet_sg_drop(old_grp);
-			gm_sg_update(grp, false);
 
-/* TODO "need S,G PRUNE => NO_INFO transition here" */
+			/*
+			 * If immediate leave drop others subscribers and proceed
+			 * to expire the MLD join.
+			 */
+			if (pim_ifp->gmp_immediate_leave) {
+				frr_each_safe (gm_packet_sg_subs, grp->subs_positive, item) {
+					gm_packet_sg_drop(item);
+				}
+				gm_sg_update(grp, true);
+			} else
+				gm_sg_update(grp, false);
 
+			/* TODO "need S,G PRUNE => NO_INFO transition here" */
 		}
 	}
 
diff --git a/pimd/pim_cmd.c b/pimd/pim_cmd.c
index fa9c6f9537..4ad75a21e7 100644
--- a/pimd/pim_cmd.c
+++ b/pimd/pim_cmd.c
@@ -5693,6 +5693,19 @@ ALIAS_YANG(interface_ip_igmp_limits,
            "Limit number of IGMPv3 sources to track\n"
            "Limit number of IGMP group memberships to track\n")
 
+DEFPY_YANG(interface_ip_igmp_immediate_leave,
+           interface_ip_igmp_immediate_leave_cmd,
+           "[no] ip igmp immediate-leave",
+           NO_STR
+           IP_STR
+           IFACE_IGMP_STR
+           "Immediately drop group memberships on receiving Leave (IGMPv2 only)\n")
+{
+	nb_cli_enqueue_change(vty, "./immediate-leave", NB_OP_MODIFY, no ? "false" : "true");
+
+	return nb_cli_apply_changes(vty, FRR_GMP_INTERFACE_XPATH, FRR_PIM_AF_XPATH_VAL);
+}
+
 DEFUN (interface_ip_pim_drprio,
        interface_ip_pim_drprio_cmd,
        "ip pim drpriority (0-4294967295)",
@@ -9140,6 +9153,7 @@ void pim_cmd_init(void)
 	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_igmp_immediate_leave_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 0a7993fd27..606fda6721 100644
--- a/pimd/pim_iface.h
+++ b/pimd/pim_iface.h
@@ -107,6 +107,9 @@ struct pim_interface {
 
 	uint32_t gm_source_limit, gm_group_limit;
 
+	/* IGMPv2 only/MLDv1 only immediate leave */
+	bool gmp_immediate_leave;
+
 	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_igmpv3.c b/pimd/pim_igmpv3.c
index 7cb168dc5d..2de2b32688 100644
--- a/pimd/pim_igmpv3.c
+++ b/pimd/pim_igmpv3.c
@@ -728,9 +728,25 @@ static void toin_incl(struct gm_group *group, int num_sources,
 static void toin_excl(struct gm_group *group, int num_sources,
 		      struct in_addr *sources)
 {
+	struct listnode *src_node, *src_next;
+	struct pim_interface *pim_ifp = group->interface->info;
 	int num_sources_tosend;
 	int i;
 
+	if (group->igmp_version == 2 && pim_ifp->gmp_immediate_leave) {
+		struct gm_source *src;
+
+		if (PIM_DEBUG_GM_TRACE)
+			zlog_debug("IGMP(v2) Immediate-leave group %pI4 on %s", &group->group_addr,
+				   group->interface->name);
+
+		igmp_group_timer_on(group, 0, group->interface->name);
+
+		for (ALL_LIST_ELEMENTS(group->group_source_list, src_node, src_next, src))
+			igmp_source_delete(src);
+		return;
+	}
+
 	/* Set SEND flag for X (sources with timer > 0) */
 	num_sources_tosend = source_mark_send_flag_by_timer(group);
 
@@ -1496,7 +1512,9 @@ void igmp_group_timer_lower_to_lmqt(struct gm_group *group)
 	pim_ifp = ifp->info;
 	ifname = ifp->name;
 
-	lmqi_dsec = pim_ifp->gm_specific_query_max_response_time_dsec;
+	lmqi_dsec = pim_ifp->gmp_immediate_leave
+			    ? 0
+			    : pim_ifp->gm_specific_query_max_response_time_dsec;
 	lmqc = pim_ifp->gm_last_member_query_count;
 	lmqt_msec = PIM_IGMP_LMQT_MSEC(
 		lmqi_dsec, lmqc); /* lmqt_msec = (100 * lmqi_dsec) * lmqc */
@@ -1531,7 +1549,9 @@ void igmp_source_timer_lower_to_lmqt(struct gm_source *source)
 	pim_ifp = ifp->info;
 	ifname = ifp->name;
 
-	lmqi_dsec = pim_ifp->gm_specific_query_max_response_time_dsec;
+	lmqi_dsec = pim_ifp->gmp_immediate_leave
+			    ? 0
+			    : pim_ifp->gm_specific_query_max_response_time_dsec;
 	lmqc = pim_ifp->gm_last_member_query_count;
 	lmqt_msec = PIM_IGMP_LMQT_MSEC(
 		lmqi_dsec, lmqc); /* lmqt_msec = (100 * lmqi_dsec) * lmqc */
diff --git a/pimd/pim_nb.c b/pimd/pim_nb.c
index 62c5d531d9..3cd5c0f4e5 100644
--- a/pimd/pim_nb.c
+++ b/pimd/pim_nb.c
@@ -743,7 +743,13 @@ const struct frr_yang_module_info frr_gmp_info = {
 				.modify = lib_interface_gmp_address_family_proxy_modify,
 			}
 		},
-{
+		{
+			.xpath = "/frr-interface:lib/interface/frr-gmp:gmp/address-family/immediate-leave",
+			.cbs = {
+				.modify = lib_interface_gmp_immediate_leave_modify,
+			}
+		},
+		{
 			.xpath = "/frr-interface:lib/interface/frr-gmp:gmp/address-family/static-group",
 			.cbs = {
 				.create = lib_interface_gmp_address_family_static_group_create,
diff --git a/pimd/pim_nb.h b/pimd/pim_nb.h
index 1656313fc2..ce7b5e43af 100644
--- a/pimd/pim_nb.h
+++ b/pimd/pim_nb.h
@@ -289,6 +289,7 @@ 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);
+int lib_interface_gmp_immediate_leave_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 c926696610..d671ea3b65 100644
--- a/pimd/pim_nb_config.c
+++ b/pimd/pim_nb_config.c
@@ -4493,6 +4493,29 @@ int lib_interface_gmp_address_family_robustness_variable_modify(
 }
 
 /*
+ * XPath: /frr-interface:lib/interface/frr-gmp:gmp/address-family/immediate-leave
+ */
+int lib_interface_gmp_immediate_leave_modify(struct nb_cb_modify_args *args)
+{
+	struct interface *ifp;
+	struct pim_interface *pim_ifp;
+
+	switch (args->event) {
+	case NB_EV_VALIDATE:
+	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->gmp_immediate_leave = yang_dnode_get_bool(args->dnode, NULL);
+		break;
+	}
+
+	return NB_OK;
+}
+
+/*
  * XPath: /frr-interface:lib/interface/frr-gmp:gmp/address-family/proxy
  */
 int lib_interface_gmp_address_family_proxy_modify(struct nb_cb_modify_args *args)
diff --git a/pimd/pim_vty.c b/pimd/pim_vty.c
index 64750a22f6..b2525998a6 100644
--- a/pimd/pim_vty.c
+++ b/pimd/pim_vty.c
@@ -471,6 +471,12 @@ int pim_config_write(struct vty *vty, int writes, struct interface *ifp,
 		++writes;
 	}
 
+	/* IF ip/ipv6 igmp/mld immediate-leave */
+	if (pim_ifp->gmp_immediate_leave) {
+		vty_out(vty, " " PIM_AF_NAME " " GM_AF_DBG " immediate-leave\n");
+		++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",
diff --git a/tests/topotests/multicast_features/test_multicast_features.py b/tests/topotests/multicast_features/test_multicast_features.py
index 9c1f4af99f..bce1c91e31 100644
--- a/tests/topotests/multicast_features/test_multicast_features.py
+++ b/tests/topotests/multicast_features/test_multicast_features.py
@@ -69,8 +69,10 @@ def build_topo(tgen):
     # R1 interface eth2
     switch = tgen.add_switch("s3")
     tgen.add_host("h1", "192.168.100.100/24", "via 192.168.100.1")
+    tgen.add_host("h3", "192.168.100.101/24", "via 192.168.100.1")
     switch.add_link(tgen.gears["r1"])
     switch.add_link(tgen.gears["h1"])
+    switch.add_link(tgen.gears["h3"])
 
     # R2 interface eth1
     switch = tgen.add_switch("s4")
@@ -170,13 +172,13 @@ def test_pim_convergence():
     # IPv6 part
     #
     out = tgen.gears["r1"].vtysh_cmd("show interface r1-eth0 json", True)
-    r1_r2_link_address = out["r1-eth0"]["ipAddresses"][1]["address"].split('/')[0]
+    r1_r2_link_address = out["r1-eth0"]["ipAddresses"][1]["address"].split("/")[0]
     out = tgen.gears["r1"].vtysh_cmd("show interface r1-eth1 json", True)
-    r1_r3_link_address = out["r1-eth1"]["ipAddresses"][1]["address"].split('/')[0]
+    r1_r3_link_address = out["r1-eth1"]["ipAddresses"][1]["address"].split("/")[0]
     out = tgen.gears["r2"].vtysh_cmd("show interface r2-eth0 json", True)
-    r2_link_address = out["r2-eth0"]["ipAddresses"][1]["address"].split('/')[0]
+    r2_link_address = out["r2-eth0"]["ipAddresses"][1]["address"].split("/")[0]
     out = tgen.gears["r3"].vtysh_cmd("show interface r3-eth0 json", True)
-    r3_link_address = out["r3-eth0"]["ipAddresses"][1]["address"].split('/')[0]
+    r3_link_address = out["r3-eth0"]["ipAddresses"][1]["address"].split("/")[0]
 
     expect_pim_peer("r1", "ipv6", "r1-eth0", r2_link_address)
     expect_pim_peer("r2", "ipv6", "r2-eth0", r1_r2_link_address)
@@ -189,11 +191,13 @@ def test_igmp_group_limit():
     if tgen.routers_have_failure():
         pytest.skip(tgen.errors)
 
-    tgen.gears["r1"].vtysh_cmd("""
+    tgen.gears["r1"].vtysh_cmd(
+        """
         configure terminal
         interface r1-eth2
          ip igmp max-groups 4
-    """)
+    """
+    )
     app_helper.run("h1", ["224.0.100.1", "h1-eth0"])
     app_helper.run("h1", ["224.0.100.2", "h1-eth0"])
     app_helper.run("h1", ["224.0.100.3", "h1-eth0"])
@@ -202,7 +206,9 @@ def test_igmp_group_limit():
     app_helper.run("h1", ["224.0.100.6", "h1-eth0"])
 
     def expect_igmp_group_count():
-        igmp_groups = tgen.gears["r1"].vtysh_cmd("show ip igmp groups json", isjson=True)
+        igmp_groups = tgen.gears["r1"].vtysh_cmd(
+            "show ip igmp groups json", isjson=True
+        )
         try:
             return len(igmp_groups["r1-eth2"]["groups"])
         except KeyError:
@@ -212,13 +218,15 @@ def test_igmp_group_limit():
 
     # Cleanup
     app_helper.stop_host("h1")
-    tgen.gears["r1"].vtysh_cmd("""
+    tgen.gears["r1"].vtysh_cmd(
+        """
         configure terminal
         interface r1-eth2
          no ip igmp max-groups 4
         exit
         clear ip igmp interfaces
-    """)
+    """
+    )
 
 
 def test_igmp_group_source_limit():
@@ -227,12 +235,14 @@ def test_igmp_group_source_limit():
     if tgen.routers_have_failure():
         pytest.skip(tgen.errors)
 
-    tgen.gears["r1"].vtysh_cmd("""
+    tgen.gears["r1"].vtysh_cmd(
+        """
         configure terminal
         interface r1-eth2
          ip igmp max-sources 4
         exit
-    """)
+    """
+    )
 
     app_helper.run("h1", ["--source=192.168.100.10", "232.0.101.10", "h1-eth0"])
     app_helper.run("h1", ["--source=192.168.100.11", "232.0.101.10", "h1-eth0"])
@@ -243,7 +253,9 @@ def test_igmp_group_source_limit():
     app_helper.run("h1", ["--source=192.168.100.16", "232.0.101.10", "h1-eth0"])
 
     def expect_igmp_group_source_count():
-        igmp_sources = tgen.gears["r1"].vtysh_cmd("show ip igmp sources json", isjson=True)
+        igmp_sources = tgen.gears["r1"].vtysh_cmd(
+            "show ip igmp sources json", isjson=True
+        )
         try:
             return len(igmp_sources["r1-eth2"]["232.0.101.10"]["sources"])
         except KeyError:
@@ -252,13 +264,15 @@ def test_igmp_group_source_limit():
     topotest.run_and_expect(expect_igmp_group_source_count, 4, count=10, wait=2)
 
     # Cleanup
-    tgen.gears["r1"].vtysh_cmd("""
+    tgen.gears["r1"].vtysh_cmd(
+        """
         configure terminal
         interface r1-eth2
          no ip igmp max-sources 4
         exit
         clear ip igmp interfaces
-    """)
+    """
+    )
     app_helper.stop_host("h1")
 
 
@@ -268,11 +282,13 @@ def test_mld_group_limit():
     if tgen.routers_have_failure():
         pytest.skip(tgen.errors)
 
-    tgen.gears["r1"].vtysh_cmd("""
+    tgen.gears["r1"].vtysh_cmd(
+        """
         configure terminal
         interface r1-eth2
          ipv6 mld max-groups 14
-    """)
+    """
+    )
     app_helper.run("h1", ["FF05::100", "h1-eth0"])
     app_helper.run("h1", ["FF05::101", "h1-eth0"])
     app_helper.run("h1", ["FF05::102", "h1-eth0"])
@@ -291,25 +307,27 @@ def test_mld_group_limit():
     app_helper.run("h1", ["FF05::115", "h1-eth0"])
 
     def expect_mld_group_count():
-        mld_groups = tgen.gears["r1"].vtysh_cmd("show ipv6 mld groups json", isjson=True)
+        mld_groups = tgen.gears["r1"].vtysh_cmd(
+            "show ipv6 mld groups json", isjson=True
+        )
         try:
             return len(mld_groups["r1-eth2"]["groups"])
         except KeyError:
             return 0
 
-
     topotest.run_and_expect(expect_mld_group_count, 14, count=10, wait=2)
 
-
     # Cleanup
     app_helper.stop_host("h1")
-    tgen.gears["r1"].vtysh_cmd("""
+    tgen.gears["r1"].vtysh_cmd(
+        """
         configure terminal
         interface r1-eth2
          no ipv6 mld max-groups 4
         exit
         clear ipv6 mld interfaces
-    """)
+    """
+    )
 
 
 def test_mld_group_source_limit():
@@ -318,12 +336,14 @@ def test_mld_group_source_limit():
     if tgen.routers_have_failure():
         pytest.skip(tgen.errors)
 
-    tgen.gears["r1"].vtysh_cmd("""
+    tgen.gears["r1"].vtysh_cmd(
+        """
         configure terminal
         interface r1-eth2
          ipv6 mld max-sources 4
         exit
-    """)
+    """
+    )
 
     app_helper.run("h1", ["--source=2001:db8:1::100", "FF35::100", "h1-eth0"])
     app_helper.run("h1", ["--source=2001:db8:1::101", "FF35::100", "h1-eth0"])
@@ -334,7 +354,9 @@ def test_mld_group_source_limit():
     app_helper.run("h1", ["--source=2001:db8:1::106", "FF35::100", "h1-eth0"])
 
     def expect_mld_source_group_count():
-        mld_sources = tgen.gears["r1"].vtysh_cmd("show ipv6 mld joins json", isjson=True)
+        mld_sources = tgen.gears["r1"].vtysh_cmd(
+            "show ipv6 mld joins json", isjson=True
+        )
         try:
             return len(mld_sources["default"]["r1-eth2"]["ff35::100"].keys())
         except KeyError:
@@ -343,14 +365,122 @@ def test_mld_group_source_limit():
     topotest.run_and_expect(expect_mld_source_group_count, 4, count=10, wait=2)
 
     # Cleanup
-    tgen.gears["r1"].vtysh_cmd("""
+    tgen.gears["r1"].vtysh_cmd(
+        """
         configure terminal
         interface r1-eth2
          no ipv6 mld max-sources 4
         exit
         clear ipv6 mld interfaces
-    """)
+    """
+    )
+    app_helper.stop_host("h1")
+
+
+def test_igmp_immediate_leave():
+    "Test IGMPv2 immediate leave feature."
+    tgen = get_topogen()
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    topotest.sysctl_assure(
+        tgen.gears["h1"], "net.ipv4.conf.h1-eth0.force_igmp_version", "2"
+    )
+    tgen.gears["r1"].vtysh_cmd(
+        """
+        configure terminal
+        interface r1-eth2
+         ip igmp immediate-leave
+    """
+    )
+
+    app_helper.run("h1", ["224.0.110.1", "h1-eth0"])
+    app_helper.run("h3", ["224.0.110.1", "h3-eth0"])
+
+    def expect_igmp_group():
+        igmp_groups = tgen.gears["r1"].vtysh_cmd(
+            "show ip igmp groups json", isjson=True
+        )
+        try:
+            for group in igmp_groups["r1-eth2"]["groups"]:
+                if group["group"] == "224.0.110.1":
+                    return True
+
+            return False
+        except KeyError:
+            return False
+
+    topotest.run_and_expect(expect_igmp_group, True, count=10, wait=2)
+
+    # Send leave and expect immediate leave
     app_helper.stop_host("h1")
+    topotest.run_and_expect(expect_igmp_group, False, count=10, wait=2)
+
+    # Clean up
+    tgen.gears["r1"].vtysh_cmd(
+        """
+        configure terminal
+        interface r1-eth2
+         no ip igmp immediate-leave
+    """
+    )
+    topotest.sysctl_assure(
+        tgen.gears["h1"], "net.ipv4.conf.h1-eth0.force_igmp_version", "0"
+    )
+    app_helper.stop_host("h3")
+
+
+def test_mldv1_immediate_leave():
+    "Test MLDv1 immediate leave feature."
+    tgen = get_topogen()
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    topotest.sysctl_assure(
+        tgen.gears["h1"], "net.ipv6.conf.h1-eth0.force_mld_version", "1"
+    )
+    tgen.gears["r1"].vtysh_cmd(
+        """
+        configure terminal
+        interface r1-eth2
+         ipv6 mld immediate-leave
+    """
+    )
+
+    app_helper.run("h1", ["ff05::2000", "h1-eth0"])
+    app_helper.run("h3", ["ff05::2000", "h3-eth0"])
+
+    def expect_mld_group():
+        igmp_groups = tgen.gears["r1"].vtysh_cmd(
+            "show ipv6 mld groups json", isjson=True
+        )
+        try:
+            for group in igmp_groups["r1-eth2"]["groups"]:
+                if group["group"] == "ff05::2000":
+                    return True
+
+            return False
+        except KeyError:
+            return False
+
+    topotest.run_and_expect(expect_mld_group, True, count=10, wait=2)
+
+    # Send leave and expect immediate leave
+    app_helper.stop_host("h1")
+    topotest.run_and_expect(expect_mld_group, False, count=10, wait=2)
+
+    # Clean up
+    tgen.gears["r1"].vtysh_cmd(
+        """
+        configure terminal
+        interface r1-eth2
+         no ipv6 mld immediate-leave
+    """
+    )
+    topotest.sysctl_assure(
+        tgen.gears["h1"], "net.ipv6.conf.h1-eth0.force_mld_version", "0"
+    )
+    app_helper.stop_host("h3")
 
 
 def test_memory_leak():
diff --git a/yang/frr-gmp.yang b/yang/frr-gmp.yang
index 26b19501f9..3843c88cff 100644
--- a/yang/frr-gmp.yang
+++ b/yang/frr-gmp.yang
@@ -186,6 +186,14 @@ module frr-gmp {
       }
     }
 
+    leaf immediate-leave {
+      type boolean;
+      default "false";
+      description
+        "Immediately drop group memberships on receiving IGMPv2/MLDv1 Leave.
+         Has no effect when IGMPv3/MLDv2 is in use.";
+    }
+
     list static-group {
       key "group-addr source-addr";
       description