bgpd: cli for srv6-locator assignment (step4)

This commit add command to speficy SRv6 locator for BGP SRv6-VPN.
CLI example is follow. CLI block of "segment-routing" is already
implemented by previous commits and it's managed by zebra.

Zebra manage just the ownership of locator's prefix.
Zlient can request to get srv6-locator's prefix chunk using
srv6_manager_get_locator_chunk() which is usuful func to
execute ZEBRA_SRV6_MANAGER_GET_LOCATOR_CHUNK api. This request
is wokring as async, And zebra calls same api to Zclients when
zebra allocate locator prefix chunk.

And then, finally zclient(bgpd) catch the information via
process_srv6_lcoator_chunk callback function.

router bgp 1
 segment-routing srv6
  locator loc1
 !
!
segment-routing
 srv6
  locators
   locator loc1
    prefix 2001:db8:1:1::/64
   !
  !
 !
!

[POINT_OF_REVIEW]
In current implementation, user can just configure srv6 locator
but user can't de-configure srv6 locator.

Signed-off-by: Hiroki Shirokura <slank.dev@gmail.com>

bgpd/bgp_vty.c

@@ -9870,6 +9870,29 @@ DEFUN_NOSH (bgp_segment_routing_srv6,
 	return CMD_SUCCESS;
 }
 
+DEFPY (bgp_srv6_locator,
+       bgp_srv6_locator_cmd,
+       "locator NAME$name",
+       "Specify SRv6 locator\n"
+       "Specify SRv6 locator\n")
+{
+	VTY_DECLVAR_CONTEXT(bgp, bgp);
+
+	if (strlen(bgp->srv6_locator_name) > 0
+	    && strcmp(name, bgp->srv6_locator_name) != 0) {
+		vty_out(vty, "srv6 locator is already configured\n");
+		return CMD_WARNING_CONFIG_FAILED;
+	} else
+		snprintf(bgp->srv6_locator_name,
+			 sizeof(bgp->srv6_locator_name), "%s", name);
+
+	int ret = bgp_zebra_srv6_manager_get_locator_chunk(name);
+	if (ret < 0)
+		return CMD_WARNING_CONFIG_FAILED;
+
+	return CMD_SUCCESS;
+}
+
 DEFUN_NOSH (exit_address_family,
        exit_address_family_cmd,
        "exit-address-family",
@@ -17887,6 +17910,14 @@ int bgp_config_write(struct vty *vty)
 		if (CHECK_FLAG(bgp->flags, BGP_FLAG_SHUTDOWN))
 			vty_out(vty, " bgp shutdown\n");
 
+		if (bgp->srv6_enabled) {
+			vty_frame(vty, " !\n segment-routing srv6\n");
+			if (bgp->srv6_locator_name)
+				vty_out(vty, "  locator %s\n",
+					bgp->srv6_locator_name);
+		}
+
+
 		/* IPv4 unicast configuration.  */
 		bgp_config_write_family(vty, bgp, AFI_IP, SAFI_UNICAST);
 
@@ -19461,6 +19492,7 @@ void bgp_vty_init(void)
 
 	/* srv6 commands */
 	install_element(BGP_NODE, &bgp_segment_routing_srv6_cmd);
+	install_element(BGP_SRV6_NODE, &bgp_srv6_locator_cmd);
 }
 
 #include "memory.h"

bgpd/bgp_zebra.c

@@ -2976,6 +2976,60 @@ static int bgp_ifp_create(struct interface *ifp)
 	return 0;
 }
 
+static void bgp_zebra_process_srv6_locator_chunk(ZAPI_CALLBACK_ARGS)
+{
+	struct stream *s = NULL;
+	uint8_t proto;
+	uint16_t instance;
+	uint16_t len;
+	char name[256] = {0};
+	struct prefix_ipv6 *chunk = NULL;
+	chunk = prefix_ipv6_new();
+
+	s = zclient->ibuf;
+	STREAM_GETC(s, proto);
+	STREAM_GETW(s, instance);
+
+	STREAM_GETW(s, len);
+	STREAM_GET(name, s, len);
+
+	STREAM_GETW(s, chunk->prefixlen);
+	STREAM_GET(&chunk->prefix, s, 16);
+
+	if (zclient->redist_default != proto) {
+		zlog_err("Got SRv6 Manager msg with wrong proto %u", proto);
+		return;
+	}
+	if (zclient->instance != instance) {
+		zlog_err("Got SRv6 Manager msg with wrong instance %u", proto);
+		return;
+	}
+
+	struct bgp *bgp = bgp_get_default();
+	if (strcmp(bgp->srv6_locator_name, name) != 0) {
+		zlog_info("name unmatch %s:%s",
+			  bgp->srv6_locator_name, name);
+		return;
+	}
+
+	struct listnode *node;
+	struct prefix_ipv6 *c;
+	for (ALL_LIST_ELEMENTS_RO(bgp->srv6_locator_chunks, node, c)) {
+		if (!prefix_cmp(c, chunk))
+			return;
+	}
+
+	listnode_add(bgp->srv6_locator_chunks, chunk);
+	vpn_leak_postchange_all();
+	return;
+
+stream_failure:
+	free(chunk);
+
+	zlog_err("%s: can't get locator_chunk!!", __func__);
+	return;
+}
+
 void bgp_zebra_init(struct thread_master *master, unsigned short instance)
 {
 	zclient_num_connects = 0;
@@ -3018,6 +3072,7 @@ void bgp_zebra_init(struct thread_master *master, unsigned short instance)
 	zclient->iptable_notify_owner = iptable_notify_owner;
 	zclient->route_notify_owner = bgp_zebra_route_notify_owner;
 	zclient->instance = instance;
+	zclient->process_srv6_locator_chunk = bgp_zebra_process_srv6_locator_chunk;
 }
 
 void bgp_zebra_destroy(void)
@@ -3415,3 +3470,8 @@ int bgp_zebra_stale_timer_update(struct bgp *bgp)
 		zlog_debug("send capabilty success");
 	return BGP_GR_SUCCESS;
 }
+
+int bgp_zebra_srv6_manager_get_locator_chunk(const char *name)
+{
+	return srv6_manager_get_locator_chunk(zclient, name);
+}

bgpd/bgp_zebra.h

@@ -113,4 +113,5 @@ extern void bgp_zebra_announce_default(struct bgp *bgp, struct nexthop *nh,
 extern int bgp_zebra_send_capabilities(struct bgp *bgp, bool disable);
 extern int bgp_zebra_update(afi_t afi, safi_t safi, vrf_id_t vrf_id, int type);
 extern int bgp_zebra_stale_timer_update(struct bgp *bgp);
+extern int bgp_zebra_srv6_manager_get_locator_chunk(const char *name);
 #endif /* _QUAGGA_BGP_ZEBRA_H */