*: new cli-nodes for BGP SRv6 VPNv4 (step4)

This commit add just CLI-nodes for MP-BGP VPN configuration
with SRv6 backend rather than MPLS. Actual configuration cli
will be implemented after this commit.

Example Configuration follow.
This cli design is based on Cisco IOS-XR but actual cli
tree design is defferent between FRR and Cisco.
It's just based on cisco.

ref:
https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r6-6/segment-routing/configuration/guide/b-segment-routing-cg-asr9000-66x/b-segment-routing-cg-asr9000-66x_chapter_011.html#concept_hwj_trf_dlb

router bgp 1
 bgp router-id 1.1.1.1
 !
 segment-routing srv6 ! new cli-node
  locator LOC1 ! this cli will be added after this commit.
 !
!

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

bgpd/bgp_vty.c

@@ -9858,6 +9858,17 @@ DEFUN_NOSH (address_family_evpn,
 	return CMD_SUCCESS;
 }
 
+DEFUN_NOSH (bgp_segment_routing_srv6,
+            bgp_segment_routing_srv6_cmd,
+            "segment-routing srv6",
+            "Segment-Routing configuration\n"
+            "Segment-Routing SRv6 configuration\n")
+{
+	VTY_DECLVAR_CONTEXT(bgp, bgp);
+	vty->node = BGP_SRV6_NODE;
+	return CMD_SUCCESS;
+}
+
 DEFUN_NOSH (exit_address_family,
        exit_address_family_cmd,
        "exit-address-family",
@@ -18020,6 +18031,13 @@ static struct cmd_node bgp_flowspecv6_node = {
 	.prompt = "%s(config-router-af-vpnv6)# ",
 };
 
+static struct cmd_node bgp_srv6_node = {
+	.name = "bgp srv6",
+	.node = BGP_SRV6_NODE,
+	.parent_node = BGP_NODE,
+	.prompt = "%s(config-router-srv6)# ",
+};
+
 static void community_list_vty(void);
 
 static void bgp_ac_neighbor(vector comps, struct cmd_token *token)
@@ -18094,6 +18112,7 @@ void bgp_vty_init(void)
 	install_node(&bgp_evpn_vni_node);
 	install_node(&bgp_flowspecv4_node);
 	install_node(&bgp_flowspecv6_node);
+	install_node(&bgp_srv6_node);
 
 	/* Install default VTY commands to new nodes.  */
 	install_default(BGP_NODE);
@@ -18109,6 +18128,7 @@ void bgp_vty_init(void)
 	install_default(BGP_FLOWSPECV6_NODE);
 	install_default(BGP_EVPN_NODE);
 	install_default(BGP_EVPN_VNI_NODE);
+	install_default(BGP_SRV6_NODE);
 
 	/* "bgp local-mac" hidden commands. */
 	install_element(CONFIG_NODE, &bgp_local_mac_cmd);
@@ -19437,6 +19457,9 @@ void bgp_vty_init(void)
 	/* tcp-mss command */
 	install_element(BGP_NODE, &neighbor_tcp_mss_cmd);
 	install_element(BGP_NODE, &no_neighbor_tcp_mss_cmd);
+
+	/* srv6 commands */
+	install_element(BGP_NODE, &bgp_segment_routing_srv6_cmd);
 }
 
 #include "memory.h"

lib/command.h

@@ -120,6 +120,7 @@ enum node_type {
 	BGP_VNC_L2_GROUP_NODE,   /* BGP VNC L2 group */
 	RFP_DEFAULTS_NODE,       /* RFP defaults node */
 	BGP_EVPN_NODE,		 /* BGP EVPN node. */
+	BGP_SRV6_NODE,		 /* BGP SRv6 node. */
 	OSPF_NODE,		 /* OSPF protocol mode */
 	OSPF6_NODE,		 /* OSPF protocol for IPv6 mode */
 	LDP_NODE,		 /* LDP protocol mode */

vtysh/vtysh.c

@@ -1507,6 +1507,13 @@ static struct cmd_node bmp_node = {
 	.parent_node = BGP_NODE,
 	.prompt = "%s(config-bgp-bmp)# "
 };
+
+static struct cmd_node bgp_srv6_node = {
+	.name = "bgp srv6",
+	.node = BGP_SRV6_NODE,
+	.parent_node = BGP_NODE,
+	.prompt = "%s(config-router-srv6)# ",
+};
 #endif /* HAVE_BGPD */
 
 #ifdef HAVE_OSPFD
@@ -1862,6 +1869,39 @@ DEFUNSH(VTYSH_BGPD,
 	return CMD_SUCCESS;
 }
 
+DEFUNSH(VTYSH_BGPD,
+        bgp_srv6,
+        bgp_srv6_cmd,
+        "segment-routing srv6",
+        "Segment-Routing configuration\n"
+        "Segment-Routing SRv6 configuration\n")
+{
+	vty->node = BGP_SRV6_NODE;
+	return CMD_SUCCESS;
+}
+
+DEFUNSH(VTYSH_BGPD,
+        exit_bgp_srv6,
+        exit_bgp_srv6_cmd,
+        "exit",
+        "exit Segment-Routing SRv6 configuration\n")
+{
+	if (vty->node == BGP_SRV6_NODE)
+		vty->node = BGP_NODE;
+	return CMD_SUCCESS;
+}
+
+DEFUNSH(VTYSH_BGPD,
+        quit_bgp_srv6,
+        quit_bgp_srv6_cmd,
+        "quit",
+        "quit Segment-Routing SRv6 configuration\n")
+{
+	if (vty->node == BGP_SRV6_NODE)
+		vty->node = BGP_NODE;
+	return CMD_SUCCESS;
+}
+
 DEFUNSH(VTYSH_BGPD, address_family_evpn, address_family_evpn_cmd,
 	"address-family <l2vpn evpn>",
 	"Enter Address Family command mode\n"
@@ -4201,6 +4241,12 @@ void vtysh_init_vty(void)
 	install_element(BMP_NODE, &bmp_exit_cmd);
 	install_element(BMP_NODE, &bmp_quit_cmd);
 	install_element(BMP_NODE, &vtysh_end_all_cmd);
+
+	install_node(&bgp_srv6_node);
+	install_element(BGP_NODE, &bgp_srv6_cmd);
+	install_element(BGP_SRV6_NODE, &exit_bgp_srv6_cmd);
+	install_element(BGP_SRV6_NODE, &quit_bgp_srv6_cmd);
+	install_element(BGP_SRV6_NODE, &vtysh_end_all_cmd);
 #endif /* HAVE_BGPD */
 
 	/* ripd */