Merge pull request #18198 from cscarpitta/feature/srv6_staticd_ua

staticd: Add support for SRv6 uA behavior

13 files changed, 419 insertions, 10 deletions

diff --git a/doc/user/static.rst b/doc/user/static.rst
index 0ce6e2107e..c1d11cf0b0 100644
--- a/doc/user/static.rst
+++ b/doc/user/static.rst
@@ -207,17 +207,18 @@ SRv6 Static SIDs Commands
    Move from srv6 node to static-sids node. In this static-sids node, user can
    configure static SRv6 SIDs.
 
-.. clicmd:: sid X:X::X:X/M locator NAME behavior <uN|uDT4|uDT6|uDT46> [vrf VRF]
+.. clicmd:: sid X:X::X:X/M locator NAME behavior <uN|uA|uDT4|uDT6|uDT46> [vrf VRF] [interface IFNAME [nexthop X:X::X:X]]
 
    Specify the locator sid manually. Configuring a local sid in a purely static mode
    by specifying the sid value would generate a unique SID.
    This feature will support the configuration of static SRv6 decapsulation on the system.
 
-   It supports four parameter options, corresponding to the following functions:
-   uN, uDT4, uDT6, uDT46
+   It supports the following behaviors: uN, uA, uDT4, uDT6, uDT46.
 
    When configuring the local sid, if the action is set to 'uN', no vrf should be set.
-   While for any other action, it is necessary to specify a specific vrf.
+   For uDT4, uDT6 and uDT46, it is necessary to specify a specific vrf.
+   The uA behavior requires the outgoing interface and optionally the IPv6 address of the Layer 3 adjacency
+   to which the packet should be forwarded.
 
 ::
 
@@ -228,6 +229,7 @@ SRv6 Static SIDs Commands
    router(config-srv6-sids)# sid fcbb:bbbb:1:fe01::/64 locator LOC1 behavior uDT6 vrf Vrf1
    router(config-srv6-sids)# sid fcbb:bbbb:1:fe02::/64 locator LOC1 behavior uDT4 vrf Vrf1
    router(config-srv6-sids)# sid fcbb:bbbb:1:fe03::/64 locator LOC1 behavior uDT46 vrf Vrf2
+   router(config-srv6-sids)# sid fcbb:bbbb:1:fe04::/64 locator LOC1 behavior uA interface eth0 nexthop 2001::2
 
    router(config-srv6-locator)# show run
    ...
@@ -237,5 +239,6 @@ SRv6 Static SIDs Commands
       sid    fcbb:bbbb:1:fe01::/64 locator LOC1 behavior uDT6 vrf Vrf1
       sid    fcbb:bbbb:1:fe02::/64 locator LOC1 behavior uDT4 vrf Vrf1
       sid    fcbb:bbbb:1:fe03::/64 locator LOC1 behavior uDT46 vrf Vrf2
+      sid    fcbb:bbbb:1:fe04::/64 locator LOC1 behavior uA interface eth0 nexthop 2001::2
        !
    ...
\ No newline at end of file
diff --git a/lib/srv6.h b/lib/srv6.h
index 3200aee70a..467f02a3c9 100644
--- a/lib/srv6.h
+++ b/lib/srv6.h
@@ -321,6 +321,7 @@ struct srv6_sid_ctx {
 	struct in_addr nh4;
 	struct in6_addr nh6;
 	vrf_id_t vrf_id;
+	ifindex_t ifindex;
 };
 
 static inline const char *seg6_mode2str(enum seg6_mode_t mode)
diff --git a/staticd/static_nb.c b/staticd/static_nb.c
index ef363bfe7e..60dc3dc788 100644
--- a/staticd/static_nb.c
+++ b/staticd/static_nb.c
@@ -157,6 +157,27 @@ const struct frr_yang_module_info frr_staticd_info = {
 			}
 		},
 		{
+			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/segment-routing/srv6/static-sids/sid/paths",
+			.cbs = {
+				.create = routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_create,
+				.destroy = routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_destroy,
+			}
+		},
+		{
+			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/segment-routing/srv6/static-sids/sid/paths/interface",
+			.cbs = {
+				.modify = routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_interface_modify,
+				.destroy = routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_interface_destroy,
+			}
+		},
+		{
+			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/segment-routing/srv6/static-sids/sid/paths/next-hop",
+			.cbs = {
+				.modify = routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_next_hop_modify,
+				.destroy = routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_next_hop_destroy,
+			}
+		},
+		{
 			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/segment-routing/srv6/static-sids/sid/locator-name",
 			.cbs = {
 				.modify = routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_locator_name_modify,
diff --git a/staticd/static_nb.h b/staticd/static_nb.h
index aa11f34021..282c9dcf11 100644
--- a/staticd/static_nb.h
+++ b/staticd/static_nb.h
@@ -96,6 +96,18 @@ int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routi
 	struct nb_cb_modify_args *args);
 int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_vrf_name_destroy(
 	struct nb_cb_destroy_args *args);
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_create(
+	struct nb_cb_create_args *args);
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_destroy(
+	struct nb_cb_destroy_args *args);
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_interface_modify(
+	struct nb_cb_modify_args *args);
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_interface_destroy(
+	struct nb_cb_destroy_args *args);
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_next_hop_modify(
+	struct nb_cb_modify_args *args);
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_next_hop_destroy(
+	struct nb_cb_destroy_args *args);
 int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_locator_name_modify(
 	struct nb_cb_modify_args *args);
 int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_locator_name_destroy(
@@ -183,6 +195,10 @@ int routing_control_plane_protocols_name_validate(
 
 #define FRR_STATIC_SRV6_SID_LOCATOR_NAME_XPATH "/locator-name"
 
+#define FRR_STATIC_SRV6_SID_INTERFACE_XPATH "/paths[path-index=%u]/interface"
+
+#define FRR_STATIC_SRV6_SID_NEXTHOP_XPATH "/paths[path-index=%u]/next-hop"
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/staticd/static_nb_config.c b/staticd/static_nb_config.c
index e2ab1f2ffe..71df15fa61 100644
--- a/staticd/static_nb_config.c
+++ b/staticd/static_nb_config.c
@@ -1231,6 +1231,113 @@ int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routi
 
 /*
  * XPath:
+ * /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/segment-routing/srv6/locators/locator/static-sids/sid/paths
+ */
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_create(
+	struct nb_cb_create_args *args)
+{
+	/* Actual setting is done in apply_finish */
+	return NB_OK;
+}
+
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_destroy(
+	struct nb_cb_destroy_args *args)
+{
+	return NB_OK;
+}
+
+/*
+ * XPath:
+ * /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/segment-routing/srv6/locators/locator/static-sids/sid/paths/interface
+ */
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_interface_modify(
+	struct nb_cb_modify_args *args)
+{
+	struct static_srv6_sid *sid;
+	const char *ifname;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	sid = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Release and uninstall existing SID, if any, before requesting the new one */
+	if (CHECK_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_VALID)) {
+		static_zebra_release_srv6_sid(sid);
+		UNSET_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_VALID);
+	}
+
+	if (CHECK_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_SENT_TO_ZEBRA)) {
+		static_zebra_srv6_sid_uninstall(sid);
+		UNSET_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_SENT_TO_ZEBRA);
+	}
+
+	ifname = yang_dnode_get_string(args->dnode, "../interface");
+	snprintf(sid->attributes.ifname, sizeof(sid->attributes.ifname), "%s", ifname);
+
+	return NB_OK;
+}
+
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_interface_destroy(
+	struct nb_cb_destroy_args *args)
+{
+	return NB_OK;
+}
+
+/*
+ * XPath:
+ * /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/segment-routing/srv6/locators/locator/static-sids/sid/paths/next-hop
+ */
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_next_hop_modify(
+	struct nb_cb_modify_args *args)
+{
+	struct static_srv6_sid *sid;
+	struct ipaddr nexthop;
+
+	switch (args->event) {
+	case NB_EV_VALIDATE:
+		zlog_info("validating nexthop %pI6", &nexthop.ipaddr_v6);
+		yang_dnode_get_ip(&nexthop, args->dnode, "../next-hop");
+		if (!IS_IPADDR_V6(&nexthop)) {
+			snprintf(args->errmsg, args->errmsg_len,
+				 "%% Nexthop must be an IPv6 address");
+			return NB_ERR_VALIDATION;
+		}
+		break;
+	case NB_EV_ABORT:
+	case NB_EV_PREPARE:
+		break;
+	case NB_EV_APPLY:
+		sid = nb_running_get_entry(args->dnode, NULL, true);
+
+		/* Release and uninstall existing SID, if any, before requesting the new one */
+		if (CHECK_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_VALID)) {
+			static_zebra_release_srv6_sid(sid);
+			UNSET_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_VALID);
+		}
+
+		if (CHECK_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_SENT_TO_ZEBRA)) {
+			static_zebra_srv6_sid_uninstall(sid);
+			UNSET_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_SENT_TO_ZEBRA);
+		}
+
+		yang_dnode_get_ip(&nexthop, args->dnode, "../next-hop");
+		sid->attributes.nh6 = nexthop.ipaddr_v6;
+
+		break;
+	}
+
+	return NB_OK;
+}
+
+int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_paths_next_hop_destroy(
+	struct nb_cb_destroy_args *args)
+{
+	return NB_OK;
+}
+
+/*
+ * XPath:
  * /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/segment-routing/srv6/locators/locator/static-sids/sid/vrf-name
  */
 int routing_control_plane_protocols_control_plane_protocol_staticd_segment_routing_srv6_local_sids_sid_locator_name_modify(
diff --git a/staticd/static_vty.c b/staticd/static_vty.c
index 5c19d23883..6e9087363d 100644
--- a/staticd/static_vty.c
+++ b/staticd/static_vty.c
@@ -1199,13 +1199,18 @@ DEFUN_NOSH (static_srv6_sids, static_srv6_sids_cmd,
 }
 
 DEFPY_YANG(srv6_sid, srv6_sid_cmd,
-      "sid X:X::X:X/M locator NAME$locator_name behavior <uN | uDT6 vrf VIEWVRFNAME | uDT4 vrf VIEWVRFNAME | uDT46 vrf VIEWVRFNAME>",
+      "sid X:X::X:X/M locator NAME$locator_name behavior <uN | uA interface INTERFACE$interface [nexthop X:X::X:X$nh6] | uDT6 vrf VIEWVRFNAME | uDT4 vrf VIEWVRFNAME | uDT46 vrf VIEWVRFNAME>",
 	  "Configure SRv6 SID\n"
       "Specify SRv6 SID\n"
 	  "Locator name\n"
       "Specify Locator name\n"
       "Specify SRv6 SID behavior\n"
       "Apply the code to a uN SID\n"
+      "Behavior uA\n"
+      "Configure the interface\n"
+      "Interface name\n"
+      "Configure the nexthop\n"
+      "IPv6 address of the nexthop\n"
       "Apply the code to an uDT6 SID\n"
       "Configure VRF name\n"
       "Specify VRF name\n"
@@ -1223,7 +1228,10 @@ DEFPY_YANG(srv6_sid, srv6_sid_cmd,
 	char xpath_sid[XPATH_MAXLEN];
 	char xpath_behavior[XPATH_MAXLEN];
 	char xpath_vrf_name[XPATH_MAXLEN];
+	char xpath_ifname[XPATH_MAXLEN];
+	char xpath_nexthop[XPATH_MAXLEN];
 	char xpath_locator_name[XPATH_MAXLEN];
+	char ab_xpath[XPATH_MAXLEN];
 
 	if (argv_find(argv, argc, "uN", &idx)) {
 		behavior = SRV6_ENDPOINT_BEHAVIOR_END_NEXT_CSID;
@@ -1236,6 +1244,8 @@ DEFPY_YANG(srv6_sid, srv6_sid_cmd,
 	} else if (argv_find(argv, argc, "uDT46", &idx)) {
 		behavior = SRV6_ENDPOINT_BEHAVIOR_END_DT46_USID;
 		vrf_name = argv[idx + 2]->arg;
+	} else if (argv_find(argv, argc, "uA", &idx)) {
+		behavior = SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID;
 	}
 
 	snprintf(xpath_srv6, sizeof(xpath_srv6), FRR_STATIC_SRV6_INFO_KEY_XPATH,
@@ -1259,6 +1269,22 @@ DEFPY_YANG(srv6_sid, srv6_sid_cmd,
 		nb_cli_enqueue_change(vty, xpath_vrf_name, NB_OP_MODIFY, vrf_name);
 	}
 
+	if (interface) {
+		snprintf(ab_xpath, sizeof(ab_xpath), FRR_STATIC_SRV6_SID_INTERFACE_XPATH, 0);
+		strlcpy(xpath_ifname, xpath_sid, sizeof(xpath_ifname));
+		strlcat(xpath_ifname, ab_xpath, sizeof(xpath_ifname));
+
+		nb_cli_enqueue_change(vty, xpath_ifname, NB_OP_MODIFY, interface);
+	}
+
+	if (nh6_str) {
+		snprintf(ab_xpath, sizeof(ab_xpath), FRR_STATIC_SRV6_SID_NEXTHOP_XPATH, 0);
+		strlcpy(xpath_nexthop, xpath_sid, sizeof(xpath_nexthop));
+		strlcat(xpath_nexthop, ab_xpath, sizeof(xpath_nexthop));
+
+		nb_cli_enqueue_change(vty, xpath_nexthop, NB_OP_MODIFY, nh6_str);
+	}
+
 	strlcpy(xpath_locator_name, xpath_sid, sizeof(xpath_locator_name));
 	strlcat(xpath_locator_name, FRR_STATIC_SRV6_SID_LOCATOR_NAME_XPATH,
 		sizeof(xpath_locator_name));
@@ -1269,7 +1295,7 @@ DEFPY_YANG(srv6_sid, srv6_sid_cmd,
 }
 
 DEFPY_YANG(no_srv6_sid, no_srv6_sid_cmd,
-      "no sid X:X::X:X/M [locator NAME$locator_name] [behavior <uN | uDT6 vrf VIEWVRFNAME | uDT4 vrf VIEWVRFNAME | uDT46 vrf VIEWVRFNAME>]",
+      "no sid X:X::X:X/M [locator NAME$locator_name] [behavior <uN | uA interface INTERFACE$interface [nexthop X:X::X:X$nh6] | uDT6 vrf VIEWVRFNAME | uDT4 vrf VIEWVRFNAME | uDT46 vrf VIEWVRFNAME>]",
       NO_STR
 	  "Configure SRv6 SID\n"
       "Specify SRv6 SID\n"
@@ -1277,6 +1303,11 @@ DEFPY_YANG(no_srv6_sid, no_srv6_sid_cmd,
       "Specify Locator name\n"
       "Specify SRv6 SID behavior\n"
       "Apply the code to a uN SID\n"
+      "Behavior uA\n"
+      "Configure the interface\n"
+      "Interface name\n"
+      "Configure the nexthop\n"
+      "IPv6 address of the nexthop\n"
       "Apply the code to an uDT6 SID\n"
       "Configure VRF name\n"
       "Specify VRF name\n"
@@ -1685,6 +1716,7 @@ static void srv6_sid_cli_show(struct vty *vty, const struct lyd_node *sid, bool
 {
 	enum srv6_endpoint_behavior_codepoint srv6_behavior;
 	struct prefix_ipv6 sid_value;
+	struct ipaddr nexthop;
 
 	yang_dnode_get_ipv6p(&sid_value, sid, "sid");
 
@@ -1756,6 +1788,16 @@ static void srv6_sid_cli_show(struct vty *vty, const struct lyd_node *sid, bool
 	if (yang_dnode_exists(sid, "vrf-name"))
 		vty_out(vty, " vrf %s", yang_dnode_get_string(sid, "vrf-name"));
 
+	if (yang_dnode_exists(sid, "paths[path-index=0]/interface")) {
+		vty_out(vty, " interface %s",
+			yang_dnode_get_string(sid, "paths[path-index=0]/interface"));
+
+		if (yang_dnode_exists(sid, "paths[path-index=0]/next-hop")) {
+			yang_dnode_get_ip(&nexthop, sid, "paths[path-index=0]/next-hop");
+			vty_out(vty, " nexthop %pI6", &nexthop.ipaddr_v6);
+		}
+	}
+
 	vty_out(vty, "\n");
 }
 
diff --git a/staticd/static_zebra.c b/staticd/static_zebra.c
index 3faeb3d37a..a6521cccc6 100644
--- a/staticd/static_zebra.c
+++ b/staticd/static_zebra.c
@@ -706,12 +706,24 @@ void static_zebra_srv6_sid_install(struct static_srv6_sid *sid)
 			return;
 		}
 		break;
+	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID:
+		action = ZEBRA_SEG6_LOCAL_ACTION_END_X;
+		ctx.nh6 = sid->attributes.nh6;
+		ifp = if_lookup_by_name(sid->attributes.ifname, VRF_DEFAULT);
+		if (!ifp) {
+			zlog_warn("Failed to install SID %pFX: failed to get interface %s",
+				  &sid->addr, sid->attributes.ifname);
+			return;
+		}
+		SET_SRV6_FLV_OP(ctx.flv.flv_ops, ZEBRA_SEG6_LOCAL_FLV_OP_NEXT_CSID);
+		ctx.flv.lcblock_len = sid->locator->block_bits_length;
+		ctx.flv.lcnode_func_len = sid->locator->node_bits_length;
+		break;
 	case SRV6_ENDPOINT_BEHAVIOR_END_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_END_NEXT_CSID_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_PSP:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_PSP_USD:
-	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID_PSP:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_OPAQUE:
@@ -834,12 +846,20 @@ void static_zebra_srv6_sid_uninstall(struct static_srv6_sid *sid)
 			return;
 		}
 		break;
+	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID:
+		ctx.nh6 = sid->attributes.nh6;
+		ifp = if_lookup_by_name(sid->attributes.ifname, VRF_DEFAULT);
+		if (!ifp) {
+			zlog_warn("Failed to install SID %pFX: failed to get interface %s",
+				  &sid->addr, sid->attributes.ifname);
+			return;
+		}
+		break;
 	case SRV6_ENDPOINT_BEHAVIOR_END_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_END_NEXT_CSID_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_PSP:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_PSP_USD:
-	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID_PSP:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_OPAQUE:
@@ -894,6 +914,7 @@ extern void static_zebra_request_srv6_sid(struct static_srv6_sid *sid)
 	struct srv6_sid_ctx ctx = {};
 	int ret = 0;
 	struct vrf *vrf;
+	struct interface *ifp;
 
 	if (!sid)
 		return;
@@ -945,12 +966,22 @@ extern void static_zebra_request_srv6_sid(struct static_srv6_sid *sid)
 		}
 
 		break;
+	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID:
+		ctx.behavior = ZEBRA_SEG6_LOCAL_ACTION_END_X;
+		ctx.nh6 = sid->attributes.nh6;
+		ifp = if_lookup_by_name(sid->attributes.ifname, VRF_DEFAULT);
+		if (!ifp) {
+			zlog_warn("Failed to request SRv6 SID %pFX: interface %s does not exist",
+				  &sid->addr, sid->attributes.ifname);
+			return;
+		}
+		ctx.ifindex = ifp->ifindex;
+		break;
 	case SRV6_ENDPOINT_BEHAVIOR_END_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_END_NEXT_CSID_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_PSP:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_PSP_USD:
-	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID_PSP:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_OPAQUE:
@@ -970,6 +1001,7 @@ extern void static_zebra_release_srv6_sid(struct static_srv6_sid *sid)
 	struct srv6_sid_ctx ctx = {};
 	struct vrf *vrf;
 	int ret = 0;
+	struct interface *ifp;
 
 	if (!sid || !CHECK_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_VALID))
 		return;
@@ -1021,12 +1053,22 @@ extern void static_zebra_release_srv6_sid(struct static_srv6_sid *sid)
 		}
 
 		break;
+	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID:
+		ctx.behavior = ZEBRA_SEG6_LOCAL_ACTION_END_X;
+		ctx.nh6 = sid->attributes.nh6;
+		ifp = if_lookup_by_name(sid->attributes.ifname, VRF_DEFAULT);
+		if (!ifp) {
+			zlog_warn("Failed to request SRv6 SID %pFX: interface %s does not exist",
+				  &sid->addr, sid->attributes.ifname);
+			return;
+		}
+		ctx.ifindex = ifp->ifindex;
+		break;
 	case SRV6_ENDPOINT_BEHAVIOR_END_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_END_NEXT_CSID_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_PSP:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_PSP_USD:
-	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID_PSP:
 	case SRV6_ENDPOINT_BEHAVIOR_END_X_NEXT_CSID_PSP_USD:
 	case SRV6_ENDPOINT_BEHAVIOR_OPAQUE:
@@ -1244,6 +1286,9 @@ static int static_zebra_srv6_sid_notify(ZAPI_CALLBACK_ARGS)
 			return 0;
 		}
 
+		if (!IPV6_ADDR_SAME(&ctx.nh6, &in6addr_any))
+			sid->attributes.nh6 = ctx.nh6;
+
 		SET_FLAG(sid->flags, STATIC_FLAG_SRV6_SID_VALID);
 
 		/*
diff --git a/tests/topotests/static_srv6_sids/expected_srv6_sids.json b/tests/topotests/static_srv6_sids/expected_srv6_sids.json
index de78878445..1796c870a6 100644
--- a/tests/topotests/static_srv6_sids/expected_srv6_sids.json
+++ b/tests/topotests/static_srv6_sids/expected_srv6_sids.json
@@ -162,5 +162,40 @@
 				}
 			]
 		}
+	],
+	"fcbb:bbbb:1:fe40::/64": [
+		{
+			"prefix": "fcbb:bbbb:1:fe40::/64",
+			"prefixLen": 64,
+			"protocol": "static",
+			"vrfId": 0,
+			"vrfName": "default",
+			"selected": true,
+			"destSelected": true,
+			"distance": 1,
+			"metric": 0,
+			"installed": true,
+			"table": 254,
+			"internalStatus": 16,
+			"internalFlags": 9,
+			"internalNextHopNum": 1,
+			"internalNextHopActiveNum": 1,
+			"nexthops": [
+				{
+					"flags": 3,
+					"fib": true,
+					"directlyConnected": true,
+					"interfaceName": "sr0",
+					"active": true,
+					"weight": 1,
+					"seg6local": {
+						"action": "End.X"
+					},
+					"seg6localContext": {
+						"nh6": "2001::2"
+					}
+				}
+			]
+		}
 	]
 }
\ No newline at end of file
diff --git a/tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_1.json b/tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_1.json
index dd0850fb3c..bd1f4bf87a 100644
--- a/tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_1.json
+++ b/tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_1.json
@@ -121,5 +121,40 @@
 				}
 			]
 		}
+	],
+	"fcbb:bbbb:1:fe40::/64": [
+		{
+			"prefix": "fcbb:bbbb:1:fe40::/64",
+			"prefixLen": 64,
+			"protocol": "static",
+			"vrfId": 0,
+			"vrfName": "default",
+			"selected": true,
+			"destSelected": true,
+			"distance": 1,
+			"metric": 0,
+			"installed": true,
+			"table": 254,
+			"internalStatus": 16,
+			"internalFlags": 9,
+			"internalNextHopNum": 1,
+			"internalNextHopActiveNum": 1,
+			"nexthops": [
+				{
+					"flags": 3,
+					"fib": true,
+					"directlyConnected": true,
+					"interfaceName": "sr0",
+					"active": true,
+					"weight": 1,
+					"seg6local": {
+						"action": "End.X"
+					},
+					"seg6localContext": {
+						"nh6": "2001::2"
+					}
+				}
+			]
+		}
 	]
 }
\ No newline at end of file
diff --git a/tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_2.json b/tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_2.json
index 4051c01425..2bd40cdb5c 100644
--- a/tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_2.json
+++ b/tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_2.json
@@ -80,5 +80,40 @@
 				}
 			]
 		}
+	],
+	"fcbb:bbbb:1:fe40::/64": [
+		{
+			"prefix": "fcbb:bbbb:1:fe40::/64",
+			"prefixLen": 64,
+			"protocol": "static",
+			"vrfId": 0,
+			"vrfName": "default",
+			"selected": true,
+			"destSelected": true,
+			"distance": 1,
+			"metric": 0,
+			"installed": true,
+			"table": 254,
+			"internalStatus": 16,
+			"internalFlags": 9,
+			"internalNextHopNum": 1,
+			"internalNextHopActiveNum": 1,
+			"nexthops": [
+				{
+					"flags": 3,
+					"fib": true,
+					"directlyConnected": true,
+					"interfaceName": "sr0",
+					"active": true,
+					"weight": 1,
+					"seg6local": {
+						"action": "End.X"
+					},
+					"seg6localContext": {
+						"nh6": "2001::2"
+					}
+				}
+			]
+		}
 	]
 }
\ No newline at end of file
diff --git a/tests/topotests/static_srv6_sids/r1/frr.conf b/tests/topotests/static_srv6_sids/r1/frr.conf
index b4904d9ac2..ce8fb88165 100644
--- a/tests/topotests/static_srv6_sids/r1/frr.conf
+++ b/tests/topotests/static_srv6_sids/r1/frr.conf
@@ -12,6 +12,7 @@ segment-routing
    sid fcbb:bbbb:1:fe10::/64 locator MAIN behavior uDT4 vrf Vrf10
    sid fcbb:bbbb:1:fe20::/64 locator MAIN behavior uDT6 vrf Vrf20
    sid fcbb:bbbb:1:fe30::/64 locator MAIN behavior uDT46 vrf Vrf30
+   sid fcbb:bbbb:1:fe40::/64 locator MAIN behavior uA interface sr0 nexthop 2001::2
   !
  !
 !
\ No newline at end of file
diff --git a/yang/frr-staticd.yang b/yang/frr-staticd.yang
index 8d0e58c0a5..3bf3a5e817 100644
--- a/yang/frr-staticd.yang
+++ b/yang/frr-staticd.yang
@@ -12,6 +12,10 @@ module frr-staticd {
     prefix frr-nexthop;
   }
 
+  import frr-interface {
+    prefix frr-interface;
+  }
+
   import ietf-inet-types {
     prefix inet;
   }
@@ -240,6 +244,24 @@ module frr-staticd {
                 description
                   "The VRF name.";
               }
+              list paths {
+                key "path-index";
+                leaf path-index {
+                  type uint8;
+                  description
+                    "Path index";
+                }
+                leaf interface {
+                  type frr-interface:interface-ref;
+                  description
+                    "Interface name.";
+                }
+                leaf next-hop {
+                  type inet:ip-address;
+                  description
+                    "Nexthop IP address.";
+                }
+              }
             }
           }
         }
diff --git a/zebra/zebra_srv6.c b/zebra/zebra_srv6.c
index 6d228c5e24..51efcceb75 100644
--- a/zebra/zebra_srv6.c
+++ b/zebra/zebra_srv6.c
@@ -18,6 +18,7 @@
 #include "zebra/zebra_srv6.h"
 #include "zebra/zebra_errors.h"
 #include "zebra/ge_netlink.h"
+#include "zebra/interface.h"
 
 #include <stdio.h>
 #include <string.h>
@@ -1745,6 +1746,13 @@ int get_srv6_sid(struct zebra_srv6_sid **sid, struct srv6_sid_ctx *ctx,
 	int ret = -1;
 	struct srv6_locator *locator;
 	char buf[256];
+	struct nhg_connected *rb_node_dep = NULL;
+	struct listnode *node;
+	struct nexthop *nexthop;
+	struct nbr_connected *nc;
+	bool found = false;
+	struct interface *ifp;
+	struct zebra_if *zebra_if;
 
 	enum srv6_sid_alloc_mode alloc_mode =
 		(sid_value) ? SRV6_SID_ALLOC_MODE_EXPLICIT
@@ -1755,6 +1763,44 @@ int get_srv6_sid(struct zebra_srv6_sid **sid, struct srv6_sid_ctx *ctx,
 			   __func__, srv6_sid_ctx2str(buf, sizeof(buf), ctx),
 			   sid_value, srv6_sid_alloc_mode2str(alloc_mode));
 
+	if (ctx->ifindex != 0 && IPV6_ADDR_SAME(&ctx->nh6, &in6addr_any)) {
+		ifp = if_lookup_by_index(ctx->ifindex, VRF_DEFAULT);
+		if (!ifp) {
+			zlog_err("%s: interface %u does not exist", __func__, ctx->ifindex);
+			return -1;
+		}
+
+		for (ALL_LIST_ELEMENTS_RO(ifp->nbr_connected, node, nc))
+			if (nc->address && nc->address->family == AF_INET6 &&
+			    IN6_IS_ADDR_LINKLOCAL(&nc->address->u.prefix6)) {
+				ctx->nh6 = nc->address->u.prefix6;
+				found = true;
+				break;
+			}
+
+		if (!found) {
+			zebra_if = ifp->info;
+
+			frr_each (nhg_connected_tree, &zebra_if->nhg_dependents, rb_node_dep) {
+				for (ALL_NEXTHOPS(rb_node_dep->nhe->nhg, nexthop)) {
+					/* skip non link-local addresses */
+					if (!IPV6_ADDR_SAME(&nexthop->gate.ipv6, &in6addr_any)) {
+						ctx->nh6 = nexthop->gate.ipv6;
+						found = true;
+						break;
+					}
+				}
+				if (found)
+					break;
+			}
+			if (!found) {
+				zlog_err("%s: cannot get SID, interface (ifindex %u) not found",
+					 __func__, ctx->ifindex);
+				return -1;
+			}
+		}
+	}
+
 	if (alloc_mode == SRV6_SID_ALLOC_MODE_EXPLICIT) {
 		/*
 		 * Explicit SID allocation: allocate a specific SID value