From: Donatas Abraitis <donatas@opensourcerouting.org>
Date: Wed, 1 May 2024 13:01:38 +0000 (+0300)
Subject: bgpd: Ignore validating the attribute flags if path-attribute is configured
X-Git-Tag: docker/9.1.1~17^2~1
X-Git-Url: https://git.puffer.fish/?a=commitdiff_plain;h=408cf3786ed68e2a4290393785c0c48d093de973;p=mirror%2Ffrr.git

bgpd: Ignore validating the attribute flags if path-attribute is configured

E.g. Cisco sends AIGP attribute as transitive, but it's wrong. Hence, the session
is teared down, because of this bgp_attr_flag_invalid() test.

Relax this check if we have `neighbor X path-attribute <discard|treat-as-withdraw>`
configured.

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
(cherry picked from commit 714e5be9a0804c0da2c9429bead274bbaefc9939)
---

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 797f05d606..7aabc2d820 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -1517,6 +1517,7 @@ static bool bgp_attr_flag_invalid(struct bgp_attr_parser_args *args)
 	uint8_t mask = BGP_ATTR_FLAG_EXTLEN;
 	const uint8_t flags = args->flags;
 	const uint8_t attr_code = args->type;
+	struct peer *peer = args->peer;
 
 	/* there may be attributes we don't know about */
 	if (attr_code > attr_flags_values_max)
@@ -1524,6 +1525,14 @@ static bool bgp_attr_flag_invalid(struct bgp_attr_parser_args *args)
 	if (attr_flags_values[attr_code] == 0)
 		return false;
 
+	/* If `neighbor X path-attribute <discard|treat-as-withdraw>` is
+	 * configured, then ignore checking optional, trasitive flags.
+	 * The attribute/route will be discarded/withdrawned later instead
+	 * of dropping the session.
+	 */
+	if (peer->discard_attrs[attr_code] || peer->withdraw_attrs[attr_code])
+		return false;
+
 	/* RFC4271, "For well-known attributes, the Transitive bit MUST be set
 	 * to
 	 * 1."