From: Donatas Abraitis <donatas@opensourcerouting.org>
Date: Mon, 15 Aug 2022 18:41:15 +0000 (+0300)
Subject: bgpd: Treat as withdraw if we receive as path with AS_SET / AS_CONFED_SET
X-Git-Tag: base_8.4~125^2
X-Git-Url: https://git.puffer.fish/?a=commitdiff_plain;h=1bd367634e79000ef32d5c1bc5e06490de2b4f84;p=matthieu%2Ffrr.git

bgpd: Treat as withdraw if we receive as path with AS_SET / AS_CONFED_SET

For now, only if the knob is enabled. Later this gonna be (most likely) removed
and routes with AS_SET / AS_CONFED_SET will be denied by default.

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

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 0135acec8f..d91c717f37 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -1515,6 +1515,19 @@ static int bgp_attr_aspath(struct bgp_attr_parser_args *args)
 					  0);
 	}
 
+	/* Conformant BGP speakers SHOULD NOT send BGP
+	 * UPDATE messages containing AS_SET or AS_CONFED_SET.  Upon receipt of
+	 * such messages, conformant BGP speakers SHOULD use the "Treat-as-
+	 * withdraw" error handling behavior as per [RFC7606].
+	 */
+	if (peer->bgp->reject_as_sets && aspath_check_as_sets(attr->aspath)) {
+		flog_err(EC_BGP_ATTR_MAL_AS_PATH,
+			 "AS_SET and AS_CONFED_SET are deprecated from %pBP",
+			 peer);
+		return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_MAL_AS_PATH,
+					  0);
+	}
+
 	/* Set aspath attribute flag. */
 	attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_AS_PATH);
 
@@ -1595,6 +1608,19 @@ static int bgp_attr_as4_path(struct bgp_attr_parser_args *args,
 					  0);
 	}
 
+	/* Conformant BGP speakers SHOULD NOT send BGP
+	 * UPDATE messages containing AS_SET or AS_CONFED_SET.  Upon receipt of
+	 * such messages, conformant BGP speakers SHOULD use the "Treat-as-
+	 * withdraw" error handling behavior as per [RFC7606].
+	 */
+	if (peer->bgp->reject_as_sets && aspath_check_as_sets(attr->aspath)) {
+		flog_err(EC_BGP_ATTR_MAL_AS_PATH,
+			 "AS_SET and AS_CONFED_SET are deprecated from %pBP",
+			 peer);
+		return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_MAL_AS_PATH,
+					  0);
+	}
+
 	/* Set aspath attribute flag. */
 	attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_AS4_PATH);