zebra, lib, vtysh: Add CLI cmd to set/unset SRv6 encap source address

- Add a new node `SRV6_ENCAP_NODE` to the CLI graph. This node allows
users to configure encapsulation parameters for SRv6, including the
source address of the outer encapsulating IPv6 header.

- Install a new CLI command `source-address` under the
`SRV6_ENCAP_NODE` node. This command is used to configure the source
address of the outer encapsulating IPv6 header.

- Install a new CLI command `no source-address` under the
`SRV6_ENCAP_NODE` node. This command is used to unset the
source address of the outer encapsulating IPv6 header and restore the
default source address.

Examples:

```
router# segment-routing
router(sr)# srv6
router(srv6)# encapsulation
router(srv6-encap)# source-address fc00:0:1::1
```

```
router# segment-routing
router(sr)# srv6
router(srv6)# encapsulation
router(srv6-encap)# no source-address
```

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

1 files changed, 44 insertions, 0 deletions

diff --git a/zebra/zebra_srv6_vty.c b/zebra/zebra_srv6_vty.c
index 3775d3dcdf..ffc67fc8a1 100644
--- a/zebra/zebra_srv6_vty.c
+++ b/zebra/zebra_srv6_vty.c
@@ -61,6 +61,13 @@ static struct cmd_node srv6_loc_node = {
 	.prompt = "%s(config-srv6-locator)# "
 };
 
+static struct cmd_node srv6_encap_node = {
+	.name = "srv6-encap",
+	.node = SRV6_ENCAP_NODE,
+	.parent_node = SRV6_NODE,
+	.prompt = "%s(config-srv6-encap)# "
+};
+
 DEFUN (show_srv6_locator,
        show_srv6_locator_cmd,
        "show segment-routing srv6 locator [json]",
@@ -391,6 +398,38 @@ DEFPY (locator_behavior,
 	return CMD_SUCCESS;
 }
 
+DEFUN_NOSH (srv6_encap,
+            srv6_encap_cmd,
+            "encapsulation",
+            "Segment Routing SRv6 encapsulation\n")
+{
+	vty->node = SRV6_ENCAP_NODE;
+	return CMD_SUCCESS;
+}
+
+DEFPY (srv6_src_addr,
+       srv6_src_addr_cmd,
+       "source-address X:X::X:X$encap_src_addr",
+       "Segment Routing SRv6 source address\n"
+       "Specify source address for SRv6 encapsulation\n")
+{
+	zebra_srv6_encap_src_addr_set(&encap_src_addr);
+	dplane_srv6_encap_srcaddr_set(&encap_src_addr, NS_DEFAULT);
+	return CMD_SUCCESS;
+}
+
+DEFPY (no_srv6_src_addr,
+       no_srv6_src_addr_cmd,
+       "no source-address [X:X::X:X$encap_src_addr]",
+       NO_STR
+       "Segment Routing SRv6 source address\n"
+       "Specify source address for SRv6 encapsulation\n")
+{
+	zebra_srv6_encap_src_addr_unset();
+	dplane_srv6_encap_srcaddr_set(&in6addr_any, NS_DEFAULT);
+	return CMD_SUCCESS;
+}
+
 static int zebra_sr_config(struct vty *vty)
 {
 	struct zebra_srv6 *srv6 = zebra_srv6_get_default();
@@ -444,22 +483,27 @@ void zebra_srv6_vty_init(void)
 	install_node(&srv6_node);
 	install_node(&srv6_locs_node);
 	install_node(&srv6_loc_node);
+	install_node(&srv6_encap_node);
 	install_default(SEGMENT_ROUTING_NODE);
 	install_default(SRV6_NODE);
 	install_default(SRV6_LOCS_NODE);
 	install_default(SRV6_LOC_NODE);
+	install_default(SRV6_ENCAP_NODE);
 
 	/* Command for change node */
 	install_element(CONFIG_NODE, &segment_routing_cmd);
 	install_element(SEGMENT_ROUTING_NODE, &srv6_cmd);
 	install_element(SEGMENT_ROUTING_NODE, &no_srv6_cmd);
 	install_element(SRV6_NODE, &srv6_locators_cmd);
+	install_element(SRV6_NODE, &srv6_encap_cmd);
 	install_element(SRV6_LOCS_NODE, &srv6_locator_cmd);
 	install_element(SRV6_LOCS_NODE, &no_srv6_locator_cmd);
 
 	/* Command for configuration */
 	install_element(SRV6_LOC_NODE, &locator_prefix_cmd);
 	install_element(SRV6_LOC_NODE, &locator_behavior_cmd);
+	install_element(SRV6_ENCAP_NODE, &srv6_src_addr_cmd);
+	install_element(SRV6_ENCAP_NODE, &no_srv6_src_addr_cmd);
 
 	/* Command for operation */
 	install_element(VIEW_NODE, &show_srv6_locator_cmd);