Merge pull request #9343 from ton31337/fix/dont_convert_by_default_to_alias

bgpd: Fix bgp routes filtering by [l]community-list

bgpd/bgp_clist.c

@@ -33,6 +33,7 @@
 #include "bgpd/bgp_community.h"
 #include "bgpd/bgp_ecommunity.h"
 #include "bgpd/bgp_lcommunity.h"
+#include "bgpd/bgp_community_alias.h"
 #include "bgpd/bgp_aspath.h"
 #include "bgpd/bgp_regex.h"
 #include "bgpd/bgp_clist.h"
@@ -557,7 +558,7 @@ static bool community_regexp_match(struct community *com, regex_t *reg)
 		str = community_str(com, false);
 
 	/* Regular expression match.  */
-	if (regexec(reg, str, 0, NULL, 0) == 0)
+	if (regexec(reg, bgp_alias2community_str(str), 0, NULL, 0) == 0)
 		return true;
 
 	/* No match.  */
@@ -627,7 +628,7 @@ static bool lcommunity_regexp_match(struct lcommunity *com, regex_t *reg)
 		str = lcommunity_str(com, false);
 
 	/* Regular expression match.  */
-	if (regexec(reg, str, 0, NULL, 0) == 0)
+	if (regexec(reg, bgp_alias2community_str(str), 0, NULL, 0) == 0)
 		return true;
 
 	/* No match.  */

bgpd/bgp_community_alias.c

@@ -20,6 +20,7 @@
 
 #include "memory.h"
 #include "lib/jhash.h"
+#include "frrstr.h"
 
 #include "bgpd/bgpd.h"
 #include "bgpd/bgp_community_alias.h"
@@ -153,6 +154,45 @@ const char *bgp_community2alias(char *community)
 	return community;
 }
 
+const char *bgp_alias2community(char *alias)
+{
+	struct community_alias ca;
+	struct community_alias *find;
+
+	memset(&ca, 0, sizeof(ca));
+	strlcpy(ca.alias, alias, sizeof(ca.alias));
+
+	find = bgp_ca_alias_lookup(&ca);
+	if (find)
+		return find->community;
+
+	return alias;
+}
+
+/* Communities structs have `->str` which is used
+ * for vty outputs and extended BGP community lists
+ * with regexp.
+ * This is a helper to convert already aliased version
+ * of communities into numerical-only format.
+ */
+const char *bgp_alias2community_str(const char *str)
+{
+	char **aliases;
+	int num;
+
+	frrstr_split(str, " ", &aliases, &num);
+	const char *communities[num + 1];
+
+	for (int i = 0; i < num; i++) {
+		communities[i] =
+			XSTRDUP(MTYPE_TMP, bgp_alias2community(aliases[i]));
+		XFREE(MTYPE_TMP, aliases[i]);
+	}
+	XFREE(MTYPE_TMP, aliases);
+
+	return frrstr_join(communities, num, " ");
+}
+
 static int bgp_community_alias_vector_walker(struct hash_bucket *bucket,
 					     void *data)
 {

bgpd/bgp_community_alias.h

@@ -42,6 +42,8 @@ extern void bgp_ca_community_delete(struct community_alias *ca);
 extern void bgp_ca_alias_delete(struct community_alias *ca);
 extern int bgp_community_alias_write(struct vty *vty);
 extern const char *bgp_community2alias(char *community);
+extern const char *bgp_alias2community(char *alias);
+extern const char *bgp_alias2community_str(const char *str);
 extern void bgp_community_alias_command_completion_setup(void);
 
 #endif /* FRR_BGP_COMMUNITY_ALIAS_H */

tests/topotests/bgp_community_alias/r1/bgpd.conf

@@ -3,6 +3,8 @@ bgp community alias 65001:1 community-r2-1
 bgp community alias 65002:2 community-r2-2
 bgp community alias 65001:1:1 large-community-r2-1
 !
+bgp large-community-list expanded r2 seq 5 permit _65001:1:1_
+!
 router bgp 65001
  no bgp ebgp-requires-policy
  neighbor 192.168.1.2 remote-as external

tests/topotests/bgp_community_alias/test_bgp-community-alias.py

@@ -138,6 +138,17 @@ def test_bgp_community_alias():
     success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
     assert result is None, "Cannot see BGP prefixes by community alias at r1"
 
+    def _bgp_show_prefixes_by_large_community_list(router):
+        output = json.loads(
+            router.vtysh_cmd("show bgp ipv4 unicast large-community-list r2 json")
+        )
+        expected = {"routes": {"172.16.16.1/32": [{"valid": True}]}}
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(_bgp_show_prefixes_by_large_community_list, router)
+    success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
+    assert result is None, "Cannot see BGP prefixes by large community list at r1"
+
 
 if __name__ == "__main__":
     args = ["-s"] + sys.argv[1:]