bgpd: Add no sid vpn per-vrf export command

The command `sid vpn per-vrf export (1-255)|auto` can be used to export
IPv4 and IPv6 routes from a VRF to the VPN RIB using a single SRv6 SID
(End.DT46 behavior).

This commit implements the no form of the above command, which can be
used to disable the export of the IPv4/IPv6 routes:
`no sid vpn per-vrf export`.

Signed-off-by: Carmine Scarpitta <carmine.scarpitta@uniroma2.it>

bgpd/bgp_mplsvpn.c

@@ -611,6 +611,18 @@ static void sid_register(struct bgp *bgp, const struct in6_addr *sid,
 	listnode_add(bgp->srv6_functions, func);
 }
 
+static void sid_unregister(struct bgp *bgp, const struct in6_addr *sid)
+{
+	struct listnode *node, *nnode;
+	struct bgp_srv6_function *func;
+
+	for (ALL_LIST_ELEMENTS(bgp->srv6_functions, node, nnode, func))
+		if (sid_same(&func->sid, sid)) {
+			listnode_delete(bgp->srv6_functions, func);
+			XFREE(MTYPE_BGP_SRV6_FUNCTION, func);
+		}
+}
+
 static bool sid_exist(struct bgp *bgp, const struct in6_addr *sid)
 {
 	struct listnode *node;
@@ -860,6 +872,69 @@ void ensure_vrf_tovpn_sid(struct bgp *bgp_vpn, struct bgp *bgp_vrf, afi_t afi)
 		return ensure_vrf_tovpn_sid_per_vrf(bgp_vpn, bgp_vrf);
 }
 
+void delete_vrf_tovpn_sid_per_af(struct bgp *bgp_vpn, struct bgp *bgp_vrf,
+				 afi_t afi)
+{
+	int debug = BGP_DEBUG(vpn, VPN_LEAK_FROM_VRF);
+	uint32_t tovpn_sid_index = 0;
+	bool tovpn_sid_auto = false;
+
+	if (debug)
+		zlog_debug("%s: try to remove SID for vrf %s: afi %s", __func__,
+			   bgp_vrf->name_pretty, afi2str(afi));
+
+	tovpn_sid_index = bgp_vrf->vpn_policy[afi].tovpn_sid_index;
+	tovpn_sid_auto = CHECK_FLAG(bgp_vrf->vpn_policy[afi].flags,
+				    BGP_VPN_POLICY_TOVPN_SID_AUTO);
+
+	/* skip when VPN is configured on vrf-instance */
+	if (tovpn_sid_index != 0 || tovpn_sid_auto)
+		return;
+
+	srv6_locator_chunk_free(bgp_vrf->vpn_policy[afi].tovpn_sid_locator);
+	bgp_vrf->vpn_policy[afi].tovpn_sid_locator = NULL;
+
+	if (bgp_vrf->vpn_policy[afi].tovpn_sid) {
+		sid_unregister(bgp_vrf, bgp_vrf->vpn_policy[afi].tovpn_sid);
+		XFREE(MTYPE_BGP_SRV6_SID, bgp_vrf->vpn_policy[afi].tovpn_sid);
+	}
+	bgp_vrf->vpn_policy[afi].tovpn_sid_transpose_label = 0;
+}
+
+void delete_vrf_tovpn_sid_per_vrf(struct bgp *bgp_vpn, struct bgp *bgp_vrf)
+{
+	int debug = BGP_DEBUG(vpn, VPN_LEAK_FROM_VRF);
+	uint32_t tovpn_sid_index = 0;
+	bool tovpn_sid_auto = false;
+
+	if (debug)
+		zlog_debug("%s: try to remove SID for vrf %s", __func__,
+			   bgp_vrf->name_pretty);
+
+	tovpn_sid_index = bgp_vrf->tovpn_sid_index;
+	tovpn_sid_auto =
+		CHECK_FLAG(bgp_vrf->vrf_flags, BGP_VPN_POLICY_TOVPN_SID_AUTO);
+
+	/* skip when VPN is configured on vrf-instance */
+	if (tovpn_sid_index != 0 || tovpn_sid_auto)
+		return;
+
+	srv6_locator_chunk_free(bgp_vrf->tovpn_sid_locator);
+	bgp_vrf->tovpn_sid_locator = NULL;
+
+	if (bgp_vrf->tovpn_sid) {
+		sid_unregister(bgp_vrf, bgp_vrf->tovpn_sid);
+		XFREE(MTYPE_BGP_SRV6_SID, bgp_vrf->tovpn_sid);
+	}
+	bgp_vrf->tovpn_sid_transpose_label = 0;
+}
+
+void delete_vrf_tovpn_sid(struct bgp *bgp_vpn, struct bgp *bgp_vrf, afi_t afi)
+{
+	delete_vrf_tovpn_sid_per_af(bgp_vpn, bgp_vrf, afi);
+	delete_vrf_tovpn_sid_per_vrf(bgp_vpn, bgp_vrf);
+}
+
 /*
  * This function embeds upper `len` bits of `label` in `sid`,
  * starting at offset `offset` as seen from the MSB of `sid`.

bgpd/bgp_mplsvpn.h

@@ -88,6 +88,10 @@ extern void vpn_leak_zebra_vrf_sid_withdraw_per_af(struct bgp *bgp, afi_t afi);
 extern void vpn_leak_zebra_vrf_sid_withdraw_per_vrf(struct bgp *bgp);
 extern int vpn_leak_label_callback(mpls_label_t label, void *lblid, bool alloc);
 extern void ensure_vrf_tovpn_sid(struct bgp *vpn, struct bgp *vrf, afi_t afi);
+extern void delete_vrf_tovpn_sid(struct bgp *vpn, struct bgp *vrf, afi_t afi);
+extern void delete_vrf_tovpn_sid_per_af(struct bgp *vpn, struct bgp *vrf,
+					afi_t afi);
+extern void delete_vrf_tovpn_sid_per_vrf(struct bgp *vpn, struct bgp *vrf);
 extern void ensure_vrf_tovpn_sid_per_af(struct bgp *vpn, struct bgp *vrf,
 					afi_t afi);
 extern void ensure_vrf_tovpn_sid_per_vrf(struct bgp *vpn, struct bgp *vrf);
@@ -258,6 +262,13 @@ static inline void vpn_leak_postchange(enum vpn_policy_direction direction,
 			vpn_leak_zebra_vrf_label_update(bgp_vrf, afi);
 		}
 
+		if (bgp_vrf->vpn_policy[afi].tovpn_sid_index == 0 &&
+		    !CHECK_FLAG(bgp_vrf->vpn_policy[afi].flags,
+				BGP_VPN_POLICY_TOVPN_SID_AUTO) &&
+		    bgp_vrf->tovpn_sid_index == 0 &&
+		    !CHECK_FLAG(bgp_vrf->vrf_flags, BGP_VRF_TOVPN_SID_AUTO))
+			delete_vrf_tovpn_sid(bgp_vpn, bgp_vrf, afi);
+
 		if (!bgp_vrf->vpn_policy[afi].tovpn_sid && !bgp_vrf->tovpn_sid)
 			ensure_vrf_tovpn_sid(bgp_vpn, bgp_vrf, afi);
 

bgpd/bgp_vty.c

@@ -9068,9 +9068,15 @@ DEFPY (bgp_sid_vpn_export,
 		 BGP_DEBUG(vpn, VPN_LEAK_FROM_VRF));
 
 	if (no) {
-		/* implement me */
+		/* when per-VRF SID is not set, do nothing */
-		vty_out(vty, "It's not implemented\n");
+		if (bgp->tovpn_sid_index == 0 &&
-		return CMD_WARNING_CONFIG_FAILED;
+		    !CHECK_FLAG(bgp->vrf_flags, BGP_VRF_TOVPN_SID_AUTO))
+			return CMD_SUCCESS;
+
+		sid_idx = 0;
+		sid_auto = false;
+		bgp->tovpn_sid_index = 0;
+		UNSET_FLAG(bgp->vrf_flags, BGP_VRF_TOVPN_SID_AUTO);
 	}
 
 	if (bgp->vpn_policy[AFI_IP].tovpn_sid_index != 0 ||
@@ -9113,7 +9119,7 @@ DEFPY (bgp_sid_vpn_export,
 		if (debug)
 			zlog_debug("%s: auto per-vrf sid alloc.", __func__);
 		SET_FLAG(bgp->vrf_flags, BGP_VRF_TOVPN_SID_AUTO);
-	} else {
+	} else if (sid_idx != 0) {
 		/* SID allocation index-mode */
 		if (debug)
 			zlog_debug("%s: idx %ld per-vrf sid alloc.", __func__,
@@ -9138,6 +9144,15 @@ ALIAS (af_label_vpn_export,
        "Between current address-family and vpn\n"
        "For routes leaked from current address-family to vpn\n")
 
+ALIAS (bgp_sid_vpn_export,
+       no_bgp_sid_vpn_export_cmd,
+       "no$no sid vpn per-vrf export",
+       NO_STR
+       "sid value for VRF\n"
+       "Between current vrf and vpn\n"
+       "sid per-VRF (both IPv4 and IPv6 address families)\n"
+       "For routes leaked from current vrf to vpn\n")
+
 DEFPY (af_nexthop_vpn_export,
        af_nexthop_vpn_export_cmd,
        "[no] nexthop vpn export [<A.B.C.D|X:X::X:X>$nexthop_su]",
@@ -19913,6 +19928,7 @@ void bgp_vty_init(void)
 	install_element(BGP_IPV4_NODE, &af_sid_vpn_export_cmd);
 	install_element(BGP_IPV6_NODE, &af_sid_vpn_export_cmd);
 	install_element(BGP_NODE, &bgp_sid_vpn_export_cmd);
+	install_element(BGP_NODE, &no_bgp_sid_vpn_export_cmd);
 
 	bgp_vty_if_init();
 }