nbctl: Added local link ipv6 to nbctl show.

This commit modifies a test to deal with the changed,
response from the command
This commit also modifies the function of ovn-nbctl show,
to also return the ipv6 link local address as mentioned

This information would be useful to have with the wider useage of
advertising IPv4 Prefixes over IPv6 next hops [0]

0: https://datatracker.ietf.org/doc/html/rfc5549

Reported-at: https://launchpad.net/bugs/2069804
Signed-off-by: MJ Ponsonby <mj.ponsonby@canonical.com>
Signed-off-by: Numan Siddique <numans@ovn.org>

tests/ovn-nbctl.at

@@ -1679,6 +1679,7 @@ AT_CHECK([ovn-nbctl show lr0 | uuidfilt], [0], [dnl
 router <0> (lr0)
     port lrp0
         mac: "00:00:00:01:02:03"
+        ipv6-lla: "fe80::200:ff:fe01:203"
         networks: [["192.168.1.1/24"]]
 ])
 

utilities/ovn-nbctl.c

@@ -780,6 +780,16 @@ print_lr(const struct nbrec_logical_router *lr, struct ds *s)
         if (lrp->mac) {
             ds_put_cstr(s, "        mac: ");
             ds_put_format(s, "\"%s\"\n", lrp->mac);
+
+            /* Have the mac address in an array. */
+            struct eth_addr ea;
+            eth_addr_from_string(lrp->mac, &ea);
+            struct in6_addr lla;
+            in6_generate_lla(ea, &lla);
+
+            ds_put_cstr(s, "        ipv6-lla: \"");
+            ipv6_format_addr(&lla, s);
+            ds_put_cstr(s, "\"\n");
         }
         if (lrp->n_networks) {
             ds_put_cstr(s, "        networks: [");