From: claudio <claudio@openbsd.org>
Date: Wed, 22 Sep 2021 18:17:49 +0000 (+0000)
Subject: Adjust handling of RIB_GENERIC_ADDPATH MRT messages. Parse it the way
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=9ad3d757e5dd84a1db277b2a491c9ecec80f6ff5;p=openbsd

Adjust handling of RIB_GENERIC_ADDPATH MRT messages. Parse it the way
OpenBGPD and GoBGP dump so that it works with all the MRT implementations
out there supporting this.
While there do some additional minor cleanup.
OK deraadt@
---

diff --git a/usr.sbin/bgpctl/mrtparser.c b/usr.sbin/bgpctl/mrtparser.c
index 3297ed56bad..5a0d39eb533 100644
--- a/usr.sbin/bgpctl/mrtparser.c
+++ b/usr.sbin/bgpctl/mrtparser.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mrtparser.c,v 1.15 2021/07/27 07:42:37 claudio Exp $ */
+/*	$OpenBSD: mrtparser.c,v 1.16 2021/09/22 18:17:49 claudio Exp $ */
 /*
  * Copyright (c) 2011 Claudio Jeker <claudio@openbsd.org>
  *
@@ -103,10 +103,8 @@ mrt_parse(int fd, struct mrt_parser *p, int verbose)
 	struct mrt_bgp_state	*s;
 	struct mrt_bgp_msg	*m;
 	void			*msg;
-	int			 addpath;
 
 	while ((msg = mrt_read_msg(fd, &h))) {
-		addpath = 0;
 		switch (ntohs(h.type)) {
 		case MSG_NULL:
 		case MSG_START:
@@ -376,7 +374,7 @@ mrt_parse_v2_rib(struct mrt_hdr *hdr, void *msg, int verbose)
 	u_int32_t	snum, path_id = 0;
 	u_int16_t	cnt, i, afi;
 	u_int8_t	safi, aid;
-	int		ret, addpath = 0;
+	int		ret;
 
 	if (len < sizeof(snum) + 1)
 		return NULL;
@@ -417,6 +415,11 @@ mrt_parse_v2_rib(struct mrt_hdr *hdr, void *msg, int verbose)
 			goto fail;
 		break;
 	case MRT_DUMP_V2_RIB_GENERIC_ADDPATH:
+		/*
+		 * RFC8050 handling for add-path has special handling for
+		 * RIB_GENERIC_ADDPATH but nobody implements it that way.
+		 * So just use the same way as for the other _ADDPATH types.
+		 */
 		r->add_path = 1;
 		/* FALLTHROUGH */
 	case MRT_DUMP_V2_RIB_GENERIC:
@@ -434,16 +437,6 @@ mrt_parse_v2_rib(struct mrt_hdr *hdr, void *msg, int verbose)
 		if ((aid = mrt_afi2aid(afi, safi, verbose)) == AID_UNSPEC)
 			goto fail;
 		
-		/* RFC8050 handling for add-path */
-		if (r->add_path) {
-			if (len < sizeof(path_id))
-				goto fail;
-			memcpy(&path_id, b, sizeof(path_id));
-			b += sizeof(path_id);
-			len -= sizeof(path_id);
-			path_id = ntohl(path_id);
-		}
-
 		/* prefix */
 		ret = mrt_extract_prefix(b, len, aid, &r->prefix,
 		    &r->prefixlen, verbose);
@@ -487,12 +480,9 @@ mrt_parse_v2_rib(struct mrt_hdr *hdr, void *msg, int verbose)
 		len -= sizeof(otm);
 		entries[i].originated = ntohl(otm);
 
-		/* RFC8050 handling for add-path */
-		if (r->add_path &&
-		    ntohs(hdr->subtype) != MRT_DUMP_V2_RIB_GENERIC_ADDPATH) {
+		if (r->add_path) {
 			if (len < sizeof(path_id) + sizeof(alen))
 				goto fail;
-			addpath = 0;
 			memcpy(&path_id, b, sizeof(path_id));
 			b += sizeof(path_id);
 			len -= sizeof(path_id);