tools: Handle sequence numbers for BGP community (large/ext) in frr-reload.py

If we add/modify community/large/ext lists without sequence numbers, and
doing frr-reload.py, then rules with sequence numbers (show running-config
always adds sequence numbers) will be deleted and new ones will be re-added.

This could lead to blackholing for some time.

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

tools/frr-reload.py

@@ -1376,6 +1376,37 @@ def ignore_delete_re_add_lines(lines_to_add, lines_to_del):
                 lines_to_add.append((add_cmd, None))
                 lines_to_del_to_del.append((ctx_keys, None))
 
+        # bgp community-list, large-community-list, extcommunity-list can be
+        # specified without a seq number. However, the running config always
+        # adds `seq X` (sequence number). So, ignore such lines as well.
+        # Examples:
+        #      bgp community-list standard clist seq 5 permit 222:213
+        #      bgp large-community-list standard llist seq 5 permit 65001:65001:1
+        #      bgp extcommunity-list standard elist seq 5 permit soo 123:123
+        re_bgp_lists = re.search(
+            "^(bgp )(community-list|large-community-list|extcommunity-list)(\s+\S+\s+)(\S+\s+)(seq \d+\s+)(permit|deny)(.*)$",
+            ctx_keys[0],
+        )
+        if re_bgp_lists:
+            found = False
+            tmpline = (
+                re_bgp_lists.group(1)
+                + re_bgp_lists.group(2)
+                + re_bgp_lists.group(3)
+                + re_bgp_lists.group(4)
+                + re_bgp_lists.group(6)
+                + re_bgp_lists.group(7)
+            )
+            for ctx in lines_to_add:
+                if ctx[0][0] == tmpline:
+                    lines_to_del_to_del.append((ctx_keys, None))
+                    lines_to_add_to_del.append(((tmpline,), None))
+                    found = True
+            if found is False:
+                add_cmd = ("no " + ctx_keys[0],)
+                lines_to_add.append((add_cmd, None))
+                lines_to_del_to_del.append((ctx_keys, None))
+
         if (
             len(ctx_keys) == 3
             and ctx_keys[0].startswith("router bgp")