mrtparser.c

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Author : claudio
Date : 2021-09-22 18:17:49
Hash : 9ad3d757
Message : 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@
usr.sbin/bgpctl/mrtparser.c
/*	$OpenBSD: mrtparser.c,v 1.16 2021/09/22 18:17:49 claudio Exp $ */
/*
 * Copyright (c) 2011 Claudio Jeker <claudio@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "mrt.h"
#include "mrtparser.h"

void	*mrt_read_msg(int, struct mrt_hdr *);
size_t	 mrt_read_buf(int, void *, size_t);

struct mrt_peer	*mrt_parse_v2_peer(struct mrt_hdr *, void *);
struct mrt_rib	*mrt_parse_v2_rib(struct mrt_hdr *, void *, int);
int	mrt_parse_dump(struct mrt_hdr *, void *, struct mrt_peer **,
	    struct mrt_rib **);
int	mrt_parse_dump_mp(struct mrt_hdr *, void *, struct mrt_peer **,
	    struct mrt_rib **, int);
int	mrt_extract_attr(struct mrt_rib_entry *, u_char *, int, u_int8_t,
	    int);

void	mrt_free_peers(struct mrt_peer *);
void	mrt_free_rib(struct mrt_rib *);
void	mrt_free_bgp_state(struct mrt_bgp_state *);
void	mrt_free_bgp_msg(struct mrt_bgp_msg *);

u_char *mrt_aspath_inflate(void *, u_int16_t, u_int16_t *);
int	mrt_extract_addr(void *, u_int, struct bgpd_addr *, u_int8_t);
int	mrt_extract_prefix(void *, u_int, u_int8_t, struct bgpd_addr *,
	    u_int8_t *, int);

struct mrt_bgp_state	*mrt_parse_state(struct mrt_hdr *, void *, int);
struct mrt_bgp_msg	*mrt_parse_msg(struct mrt_hdr *, void *, int);

void *
mrt_read_msg(int fd, struct mrt_hdr *hdr)
{
	void *buf;

	bzero(hdr, sizeof(*hdr));
	if (mrt_read_buf(fd, hdr, sizeof(*hdr)) != sizeof(*hdr))
		return (NULL);

	if ((buf = malloc(ntohl(hdr->length))) == NULL)
		err(1, "malloc(%d)", hdr->length);

	if (mrt_read_buf(fd, buf, ntohl(hdr->length)) != ntohl(hdr->length)) {
		free(buf);
		return (NULL);
	}
	return (buf);
}

size_t
mrt_read_buf(int fd, void *buf, size_t len)
{
	char *b = buf;
	ssize_t n;

	while (len > 0) {
		if ((n = read(fd, b, len)) == -1) {
			if (errno == EINTR)
				continue;
			err(1, "read");
		}
		if (n == 0)
			break;
		b += n;
		len -= n;
	}

	return (b - (char *)buf);
}

void
mrt_parse(int fd, struct mrt_parser *p, int verbose)
{
	struct mrt_hdr		h;
	struct mrt_peer		*pctx = NULL;
	struct mrt_rib		*r;
	struct mrt_bgp_state	*s;
	struct mrt_bgp_msg	*m;
	void			*msg;

	while ((msg = mrt_read_msg(fd, &h))) {
		switch (ntohs(h.type)) {
		case MSG_NULL:
		case MSG_START:
		case MSG_DIE:
		case MSG_I_AM_DEAD:
		case MSG_PEER_DOWN:
		case MSG_PROTOCOL_BGP:
		case MSG_PROTOCOL_IDRP:
		case MSG_PROTOCOL_BGP4PLUS:
		case MSG_PROTOCOL_BGP4PLUS1:
			if (verbose)
				printf("deprecated MRT type %d\n",
				    ntohs(h.type));
			break;
		case MSG_PROTOCOL_RIP:
		case MSG_PROTOCOL_RIPNG:
		case MSG_PROTOCOL_OSPF:
		case MSG_PROTOCOL_ISIS_ET:
		case MSG_PROTOCOL_ISIS:
		case MSG_PROTOCOL_OSPFV3_ET:
		case MSG_PROTOCOL_OSPFV3:
			if (verbose)
				printf("unsuported MRT type %d\n",
				    ntohs(h.type));
			break;
		case MSG_TABLE_DUMP:
			switch (ntohs(h.subtype)) {
			case MRT_DUMP_AFI_IP:
			case MRT_DUMP_AFI_IPv6:
				if (p->dump == NULL)
					break;
				if (mrt_parse_dump(&h, msg, &pctx, &r) == 0) {
					if (p->dump)
						p->dump(r, pctx, p->arg);
					mrt_free_rib(r);
				}
				break;
			default:
				if (verbose)
					printf("unknown AFI %d in table dump\n",
					    ntohs(h.subtype));
				break;
			}
			break;
		case MSG_TABLE_DUMP_V2:
			switch (ntohs(h.subtype)) {
			case MRT_DUMP_V2_PEER_INDEX_TABLE:
				if (p->dump == NULL)
					break;
				if (pctx)
					mrt_free_peers(pctx);
				pctx = mrt_parse_v2_peer(&h, msg);
				break;
			case MRT_DUMP_V2_RIB_IPV4_UNICAST:
			case MRT_DUMP_V2_RIB_IPV4_MULTICAST:
			case MRT_DUMP_V2_RIB_IPV6_UNICAST:
			case MRT_DUMP_V2_RIB_IPV6_MULTICAST:
			case MRT_DUMP_V2_RIB_GENERIC:
			case MRT_DUMP_V2_RIB_IPV4_UNICAST_ADDPATH:
			case MRT_DUMP_V2_RIB_IPV4_MULTICAST_ADDPATH:
			case MRT_DUMP_V2_RIB_IPV6_UNICAST_ADDPATH:
			case MRT_DUMP_V2_RIB_IPV6_MULTICAST_ADDPATH:
			case MRT_DUMP_V2_RIB_GENERIC_ADDPATH:
				if (p->dump == NULL)
					break;
				r = mrt_parse_v2_rib(&h, msg, verbose);
				if (r) {
					if (p->dump)
						p->dump(r, pctx, p->arg);
					mrt_free_rib(r);
				}
				break;
			default:
				if (verbose)
					printf("unhandled DUMP_V2 subtype %d\n",
					    ntohs(h.subtype));
				break;
			}
			break;
		case MSG_PROTOCOL_BGP4MP_ET:
		case MSG_PROTOCOL_BGP4MP:
			switch (ntohs(h.subtype)) {
			case BGP4MP_STATE_CHANGE:
			case BGP4MP_STATE_CHANGE_AS4:
				if ((s = mrt_parse_state(&h, msg, verbose))) {
					if (p->state)
						p->state(s, p->arg);
					free(s);
				}
				break;
			case BGP4MP_MESSAGE:
			case BGP4MP_MESSAGE_AS4:
			case BGP4MP_MESSAGE_LOCAL:
			case BGP4MP_MESSAGE_AS4_LOCAL:
			case BGP4MP_MESSAGE_ADDPATH:
			case BGP4MP_MESSAGE_AS4_ADDPATH:
			case BGP4MP_MESSAGE_LOCAL_ADDPATH:
			case BGP4MP_MESSAGE_AS4_LOCAL_ADDPATH:
				if ((m = mrt_parse_msg(&h, msg, verbose))) {
					if (p->message)
						p->message(m, p->arg);
					free(m->msg);
					free(m);
				}
				break;
			case BGP4MP_ENTRY:
				if (p->dump == NULL)
					break;
				if (mrt_parse_dump_mp(&h, msg, &pctx, &r,
				    verbose) == 0) {
					if (p->dump)
						p->dump(r, pctx, p->arg);
					mrt_free_rib(r);
				}
				break;
			default:
				if (verbose)
					printf("unhandled BGP4MP subtype %d\n",
					    ntohs(h.subtype));
				break;
			}
			break;
		default:
			if (verbose)
				printf("unknown MRT type %d\n", ntohs(h.type));
			break;
		}
		free(msg);
	}
	if (pctx)
		mrt_free_peers(pctx);
}

static int
mrt_afi2aid(int afi, int safi, int verbose)
{
	switch (afi) {
	case MRT_DUMP_AFI_IP:
		if (safi == -1 || safi == 1 || safi == 2)
			return AID_INET;
		else if (safi == 128)
			return AID_VPN_IPv4;
		break;
	case MRT_DUMP_AFI_IPv6:
		if (safi == -1 || safi == 1 || safi == 2)
			return AID_INET6;
		else if (safi == 128)
			return AID_VPN_IPv6;
		break;
	default:
		break;
	}
	if (verbose)
		printf("unhandled AFI/SAFI %d/%d\n", afi, safi);
	return AID_UNSPEC;
}

struct mrt_peer *
mrt_parse_v2_peer(struct mrt_hdr *hdr, void *msg)
{
	struct mrt_peer_entry	*peers = NULL;
	struct mrt_peer	*p;
	u_int8_t	*b = msg;
	u_int32_t	bid, as4;
	u_int16_t	cnt, i, as2;
	u_int		len = ntohl(hdr->length);

	if (len < 8)	/* min msg size */
		return NULL;

	p = calloc(1, sizeof(struct mrt_peer));
	if (p == NULL)
		err(1, "calloc");

	/* collector bgp id */
	memcpy(&bid, b, sizeof(bid));
	b += sizeof(bid);
	len -= sizeof(bid);
	p->bgp_id = ntohl(bid);

	/* view name length */
	memcpy(&cnt, b, sizeof(cnt));
	b += sizeof(cnt);
	len -= sizeof(cnt);
	cnt = ntohs(cnt);

	/* view name */
	if (cnt > len)
		goto fail;
	if (cnt != 0) {
		if ((p->view = malloc(cnt + 1)) == NULL)
			err(1, "malloc");
		memcpy(p->view, b, cnt);
		p->view[cnt] = 0;
	} else
		if ((p->view = strdup("")) == NULL)
			err(1, "strdup");
	b += cnt;
	len -= cnt;

	/* peer_count */
	if (len < sizeof(cnt))
		goto fail;
	memcpy(&cnt, b, sizeof(cnt));
	b += sizeof(cnt);
	len -= sizeof(cnt);
	cnt = ntohs(cnt);

	/* peer entries */
	if ((peers = calloc(cnt, sizeof(struct mrt_peer_entry))) == NULL)
		err(1, "calloc");
	for (i = 0; i < cnt; i++) {
		u_int8_t type;

		if (len < sizeof(u_int8_t) + sizeof(u_int32_t))
			goto fail;
		type = *b++;
		len -= 1;
		memcpy(&bid, b, sizeof(bid));
		b += sizeof(bid);
		len -= sizeof(bid);
		peers[i].bgp_id = ntohl(bid);

		if (type & MRT_DUMP_V2_PEER_BIT_I) {
			if (mrt_extract_addr(b, len, &peers[i].addr,
			    AID_INET6) == -1)
				goto fail;
			b += sizeof(struct in6_addr);
			len -= sizeof(struct in6_addr);
		} else {
			if (mrt_extract_addr(b, len, &peers[i].addr,
			    AID_INET) == -1)
				goto fail;
			b += sizeof(struct in_addr);
			len -= sizeof(struct in_addr);
		}

		if (type & MRT_DUMP_V2_PEER_BIT_A) {
			memcpy(&as4, b, sizeof(as4));
			b += sizeof(as4);
			len -= sizeof(as4);
			as4 = ntohl(as4);
		} else {
			memcpy(&as2, b, sizeof(as2));
			b += sizeof(as2);
			len -= sizeof(as2);
			as4 = ntohs(as2);
		}
		peers[i].asnum = as4;
	}
	p->peers = peers;
	p->npeers = cnt;
	return (p);
fail:
	mrt_free_peers(p);
	free(peers);
	return (NULL);
}

struct mrt_rib *
mrt_parse_v2_rib(struct mrt_hdr *hdr, void *msg, int verbose)
{
	struct mrt_rib_entry *entries = NULL;
	struct mrt_rib	*r;
	u_int8_t	*b = msg;
	u_int		len = ntohl(hdr->length);
	u_int32_t	snum, path_id = 0;
	u_int16_t	cnt, i, afi;
	u_int8_t	safi, aid;
	int		ret;

	if (len < sizeof(snum) + 1)
		return NULL;

	r = calloc(1, sizeof(struct mrt_rib));
	if (r == NULL)
		err(1, "calloc");

	/* seq_num */
	memcpy(&snum, b, sizeof(snum));
	b += sizeof(snum);
	len -= sizeof(snum);
	r->seqnum = ntohl(snum);

	switch (ntohs(hdr->subtype)) {
	case MRT_DUMP_V2_RIB_IPV4_UNICAST_ADDPATH:
	case MRT_DUMP_V2_RIB_IPV4_MULTICAST_ADDPATH:
		r->add_path = 1;
		/* FALLTHROUGH */
	case MRT_DUMP_V2_RIB_IPV4_UNICAST:
	case MRT_DUMP_V2_RIB_IPV4_MULTICAST:
		/* prefix */
		ret = mrt_extract_prefix(b, len, AID_INET, &r->prefix,
		    &r->prefixlen, verbose);
		if (ret == 1)
			goto fail;
		break;
	case MRT_DUMP_V2_RIB_IPV6_UNICAST_ADDPATH:
	case MRT_DUMP_V2_RIB_IPV6_MULTICAST_ADDPATH:
		r->add_path = 1;
		/* FALLTHROUGH */
	case MRT_DUMP_V2_RIB_IPV6_UNICAST:
	case MRT_DUMP_V2_RIB_IPV6_MULTICAST:
		/* prefix */
		ret = mrt_extract_prefix(b, len, AID_INET6, &r->prefix,
		    &r->prefixlen, verbose);
		if (ret == 1)
			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:
		/* fetch AFI/SAFI pair */
		if (len < 3)
			goto fail;
		memcpy(&afi, b, sizeof(afi));
		b += sizeof(afi);
		len -= sizeof(afi);
		afi = ntohs(afi);

		safi = *b++;
		len -= 1;

		if ((aid = mrt_afi2aid(afi, safi, verbose)) == AID_UNSPEC)
			goto fail;
		
		/* prefix */
		ret = mrt_extract_prefix(b, len, aid, &r->prefix,
		    &r->prefixlen, verbose);
		if (ret == 1)
			goto fail;
		break;
	default:
		errx(1, "unknonw subtype %hd", ntohs(hdr->subtype));
	}

	/* adjust length */
	b += ret;
	len -= ret;

	/* entries count */
	if (len < sizeof(cnt))
		goto fail;
	memcpy(&cnt, b, sizeof(cnt));
	b += sizeof(cnt);
	len -= sizeof(cnt);
	cnt = ntohs(cnt);
	r->nentries = cnt;

	/* entries */
	if ((entries = calloc(cnt, sizeof(struct mrt_rib_entry))) == NULL)
		err(1, "calloc");
	for (i = 0; i < cnt; i++) {
		u_int32_t	otm;
		u_int16_t	pix, alen;
		if (len < 2 * sizeof(u_int16_t) + sizeof(u_int32_t))
			goto fail;
		/* peer index */
		memcpy(&pix, b, sizeof(pix));
		b += sizeof(pix);
		len -= sizeof(pix);
		entries[i].peer_idx = ntohs(pix);

		/* originated */
		memcpy(&otm, b, sizeof(otm));
		b += sizeof(otm);
		len -= sizeof(otm);
		entries[i].originated = ntohl(otm);

		if (r->add_path) {
			if (len < sizeof(path_id) + sizeof(alen))
				goto fail;
			memcpy(&path_id, b, sizeof(path_id));
			b += sizeof(path_id);
			len -= sizeof(path_id);
			path_id = ntohl(path_id);
		}
		entries[i].path_id = path_id;

		/* attr_len */
		memcpy(&alen, b, sizeof(alen));
		b += sizeof(alen);
		len -= sizeof(alen);
		alen = ntohs(alen);

		/* attr */
		if (len < alen)
			goto fail;
		if (mrt_extract_attr(&entries[i], b, alen,
		    r->prefix.aid, 1) == -1)
			goto fail;
		b += alen;
		len -= alen;
	}
	r->entries = entries;
	return (r);
fail:
	mrt_free_rib(r);
	free(entries);
	return (NULL);
}

int
mrt_parse_dump(struct mrt_hdr *hdr, void *msg, struct mrt_peer **pp,
    struct mrt_rib **rp)
{
	struct mrt_peer		*p;
	struct mrt_rib		*r;
	struct mrt_rib_entry	*re;
	u_int8_t		*b = msg;
	u_int			 len = ntohl(hdr->length);
	u_int16_t		 asnum, alen;

	if (*pp == NULL) {
		*pp = calloc(1, sizeof(struct mrt_peer));
		if (*pp == NULL)
			err(1, "calloc");
		(*pp)->peers = calloc(1, sizeof(struct mrt_peer_entry));
		if ((*pp)->peers == NULL)
			err(1, "calloc");
		(*pp)->npeers = 1;
	}
	p = *pp;

	*rp = r = calloc(1, sizeof(struct mrt_rib));
	if (r == NULL)
		err(1, "calloc");
	re = calloc(1, sizeof(struct mrt_rib_entry));
	if (re == NULL)
		err(1, "calloc");
	r->nentries = 1;
	r->entries = re;

	if (len < 2 * sizeof(u_int16_t))
		goto fail;
	/* view */
	b += sizeof(u_int16_t);
	len -= sizeof(u_int16_t);
	/* seqnum */
	memcpy(&r->seqnum, b, sizeof(u_int16_t));
	b += sizeof(u_int16_t);
	len -= sizeof(u_int16_t);
	r->seqnum = ntohs(r->seqnum);

	switch (ntohs(hdr->subtype)) {
	case MRT_DUMP_AFI_IP:
		if (mrt_extract_addr(b, len, &r->prefix, AID_INET) == -1)
			goto fail;
		b += sizeof(struct in_addr);
		len -= sizeof(struct in_addr);
		break;
	case MRT_DUMP_AFI_IPv6:
		if (mrt_extract_addr(b, len, &r->prefix, AID_INET6) == -1)
			goto fail;
		b += sizeof(struct in6_addr);
		len -= sizeof(struct in6_addr);
		break;
	}
	if (len < 2 * sizeof(u_int32_t) + 2 * sizeof(u_int16_t) + 2)
		goto fail;
	r->prefixlen = *b++;
	len -= 1;
	/* status */
	b += 1;
	len -= 1;
	/* originated */
	memcpy(&re->originated, b, sizeof(u_int32_t));
	b += sizeof(u_int32_t);
	len -= sizeof(u_int32_t);
	re->originated = ntohl(re->originated);
	/* peer ip */
	switch (ntohs(hdr->subtype)) {
	case MRT_DUMP_AFI_IP:
		if (mrt_extract_addr(b, len, &p->peers->addr, AID_INET) == -1)
			goto fail;
		b += sizeof(struct in_addr);
		len -= sizeof(struct in_addr);
		break;
	case MRT_DUMP_AFI_IPv6:
		if (mrt_extract_addr(b, len, &p->peers->addr, AID_INET6) == -1)
			goto fail;
		b += sizeof(struct in6_addr);
		len -= sizeof(struct in6_addr);
		break;
	}
	memcpy(&asnum, b, sizeof(asnum));
	b += sizeof(asnum);
	len -= sizeof(asnum);
	p->peers->asnum = ntohs(asnum);

	memcpy(&alen, b, sizeof(alen));
	b += sizeof(alen);
	len -= sizeof(alen);
	alen = ntohs(alen);

	/* attr */
	if (len < alen)
		goto fail;
	if (mrt_extract_attr(re, b, alen, r->prefix.aid, 0) == -1)
		goto fail;
	b += alen;
	len -= alen;

	return (0);
fail:
	mrt_free_rib(r);
	return (-1);
}

int
mrt_parse_dump_mp(struct mrt_hdr *hdr, void *msg, struct mrt_peer **pp,
    struct mrt_rib **rp, int verbose)
{
	struct mrt_peer		*p;
	struct mrt_rib		*r;
	struct mrt_rib_entry	*re;
	u_int8_t		*b = msg;
	u_int			 len = ntohl(hdr->length);
	u_int16_t		 asnum, alen, afi;
	u_int8_t		 safi, nhlen, aid;
	int			 ret;

	/* just ignore the microsec field for _ET header for now */
	if (ntohs(hdr->type) == MSG_PROTOCOL_BGP4MP_ET) {
		b = (char *)b + sizeof(u_int32_t);
		len -= sizeof(u_int32_t);
	}

	if (*pp == NULL) {
		*pp = calloc(1, sizeof(struct mrt_peer));
		if (*pp == NULL)
			err(1, "calloc");
		(*pp)->peers = calloc(1, sizeof(struct mrt_peer_entry));
		if ((*pp)->peers == NULL)
			err(1, "calloc");
		(*pp)->npeers = 1;
	}
	p = *pp;

	*rp = r = calloc(1, sizeof(struct mrt_rib));
	if (r == NULL)
		err(1, "calloc");
	re = calloc(1, sizeof(struct mrt_rib_entry));
	if (re == NULL)
		err(1, "calloc");
	r->nentries = 1;
	r->entries = re;

	if (len < 4 * sizeof(u_int16_t))
		goto fail;
	/* source AS */
	b += sizeof(u_int16_t);
	len -= sizeof(u_int16_t);
	/* dest AS */
	memcpy(&asnum, b, sizeof(asnum));
	b += sizeof(asnum);
	len -= sizeof(asnum);
	p->peers->asnum = ntohs(asnum);
	/* iface index */
	b += sizeof(u_int16_t);
	len -= sizeof(u_int16_t);
	/* afi */
	memcpy(&afi, b, sizeof(afi));
	b += sizeof(afi);
	len -= sizeof(afi);
	afi = ntohs(afi);

	/* source + dest ip */
	switch (afi) {
	case MRT_DUMP_AFI_IP:
		if (len < 2 * sizeof(struct in_addr))
			goto fail;
		/* source IP */
		b += sizeof(struct in_addr);
		len -= sizeof(struct in_addr);
		/* dest IP */
		if (mrt_extract_addr(b, len, &p->peers->addr, AID_INET) == -1)
			goto fail;
		b += sizeof(struct in_addr);
		len -= sizeof(struct in_addr);
		break;
	case MRT_DUMP_AFI_IPv6:
		if (len < 2 * sizeof(struct in6_addr))
			goto fail;
		/* source IP */
		b += sizeof(struct in6_addr);
		len -= sizeof(struct in6_addr);
		/* dest IP */
		if (mrt_extract_addr(b, len, &p->peers->addr, AID_INET6) == -1)
			goto fail;
		b += sizeof(struct in6_addr);
		len -= sizeof(struct in6_addr);
		break;
	}

	if (len < 2 * sizeof(u_int16_t) + 2 * sizeof(u_int32_t))
		goto fail;
	/* view + status */
	b += 2 * sizeof(u_int16_t);
	len -= 2 * sizeof(u_int16_t);
	/* originated */
	memcpy(&re->originated, b, sizeof(u_int32_t));
	b += sizeof(u_int32_t);
	len -= sizeof(u_int32_t);
	re->originated = ntohl(re->originated);

	/* afi */
	memcpy(&afi, b, sizeof(afi));
	b += sizeof(afi);
	len -= sizeof(afi);
	afi = ntohs(afi);

	/* safi */
	safi = *b++;
	len -= 1;

	if ((aid = mrt_afi2aid(afi, safi, verbose)) == AID_UNSPEC)
		goto fail;

	/* nhlen */
	nhlen = *b++;
	len -= 1;

	/* nexthop */
	if (mrt_extract_addr(b, len, &re->nexthop, aid) == -1)
		goto fail;
	if (len < nhlen)
		goto fail;
	b += nhlen;
	len -= nhlen;

	/* prefix */
	ret = mrt_extract_prefix(b, len, aid, &r->prefix, &r->prefixlen,
	    verbose);
	if (ret == 1)
		goto fail;
	b += ret;
	len -= ret;

	memcpy(&alen, b, sizeof(alen));
	b += sizeof(alen);
	len -= sizeof(alen);
	alen = ntohs(alen);

	/* attr */
	if (len < alen)
		goto fail;
	if (mrt_extract_attr(re, b, alen, r->prefix.aid, 0) == -1)
		goto fail;
	b += alen;
	len -= alen;

	return (0);
fail:
	mrt_free_rib(r);
	return (-1);
}

int
mrt_extract_attr(struct mrt_rib_entry *re, u_char *a, int alen, u_int8_t aid,
    int as4)
{
	struct mrt_attr	*ap;
	u_int32_t	tmp;
	u_int16_t	attr_len;
	u_int8_t	type, flags, *attr;

	do {
		if (alen < 3)
			return (-1);
		attr = a;
		flags = *a++;
		alen -= 1;
		type = *a++;
		alen -= 1;

		if (flags & MRT_ATTR_EXTLEN) {
			if (alen < 2)
				return (-1);
			memcpy(&attr_len, a, sizeof(attr_len));
			attr_len = ntohs(attr_len);
			a += sizeof(attr_len);
			alen -= sizeof(attr_len);
		} else {
			attr_len = *a++;
			alen -= 1;
		}
		switch (type) {
		case MRT_ATTR_ORIGIN:
			if (attr_len != 1)
				return (-1);
			re->origin = *a;
			break;
		case MRT_ATTR_ASPATH:
			if (as4) {
				re->aspath_len = attr_len;
				if ((re->aspath = malloc(attr_len)) == NULL)
					err(1, "malloc");
				memcpy(re->aspath, a, attr_len);
			} else {
				re->aspath = mrt_aspath_inflate(a, attr_len,
				    &re->aspath_len);
				if (re->aspath == NULL)
					return (-1);
			}
			break;
		case MRT_ATTR_NEXTHOP:
			if (attr_len != 4)
				return (-1);
			if (aid != AID_INET)
				break;
			memcpy(&tmp, a, sizeof(tmp));
			re->nexthop.aid = AID_INET;
			re->nexthop.v4.s_addr = tmp;
			break;
		case MRT_ATTR_MED:
			if (attr_len != 4)
				return (-1);
			memcpy(&tmp, a, sizeof(tmp));
			re->med = ntohl(tmp);
			break;
		case MRT_ATTR_LOCALPREF:
			if (attr_len != 4)
				return (-1);
			memcpy(&tmp, a, sizeof(tmp));
			re->local_pref = ntohl(tmp);
			break;
		case MRT_ATTR_MP_REACH_NLRI:
			/*
			 * XXX horrible hack:
			 * Once again IETF and the real world differ in the
			 * implementation. In short the abbreviated MP_NLRI
			 * hack in the standard is not used in real life.
			 * Detect the two cases by looking at the first byte
			 * of the payload (either the nexthop addr length (RFC)
			 * or the high byte of the AFI (old form)). If the
			 * first byte matches the expected nexthop length it
			 * is expected to be the RFC 6396 encoding.
			 */
			if (*a != attr_len - 1) {
				a += 3;
				alen -= 3;
				attr_len -= 3;
			}
			switch (aid) {
			case AID_INET6:
				if (attr_len < sizeof(struct in6_addr) + 1)
					return (-1);
				re->nexthop.aid = aid;
				memcpy(&re->nexthop.v6, a + 1,
				    sizeof(struct in6_addr));
				break;
			case AID_VPN_IPv4:
				if (attr_len < sizeof(u_int64_t) +
				    sizeof(struct in_addr))
					return (-1);
				re->nexthop.aid = aid;
				memcpy(&tmp, a + 1 + sizeof(u_int64_t),
				    sizeof(tmp));
				re->nexthop.v4.s_addr = tmp;
				break;
			case AID_VPN_IPv6:
				if (attr_len < sizeof(u_int64_t) +
				    sizeof(struct in6_addr))
					return (-1);
				re->nexthop.aid = aid;
				memcpy(&re->nexthop.v6,
				    a + 1 + sizeof(u_int64_t),
				    sizeof(struct in6_addr));
				break;
			}
			break;
		case MRT_ATTR_AS4PATH:
			if (!as4) {
				free(re->aspath);
				re->aspath_len = attr_len;
				if ((re->aspath = malloc(attr_len)) == NULL)
					err(1, "malloc");
				memcpy(re->aspath, a, attr_len);
				break;
			}
			/* FALLTHROUGH */
		default:
			re->nattrs++;
			if (re->nattrs >= UCHAR_MAX)
				err(1, "too many attributes");
			ap = reallocarray(re->attrs,
			    re->nattrs, sizeof(struct mrt_attr));
			if (ap == NULL)
				err(1, "realloc");
			re->attrs = ap;
			ap = re->attrs + re->nattrs - 1;
			ap->attr_len = a + attr_len - attr;
			if ((ap->attr = malloc(ap->attr_len)) == NULL)
				err(1, "malloc");
			memcpy(ap->attr, attr, ap->attr_len);
			break;
		}
		a += attr_len;
		alen -= attr_len;
	} while (alen > 0);

	return (0);
}

void
mrt_free_peers(struct mrt_peer *p)
{
	free(p->peers);
	free(p->view);
	free(p);
}

void
mrt_free_rib(struct mrt_rib *r)
{
	u_int16_t	i, j;

	for (i = 0; i < r->nentries && r->entries; i++) {
		for (j = 0; j < r->entries[i].nattrs; j++)
			 free(r->entries[i].attrs[j].attr);
		free(r->entries[i].attrs);
		free(r->entries[i].aspath);
	}

	free(r->entries);
	free(r);
}

void
mrt_free_bgp_state(struct mrt_bgp_state *s)
{
	free(s);
}

void
mrt_free_bgp_msg(struct mrt_bgp_msg *m)
{
	free(m->msg);
	free(m);
}

u_char *
mrt_aspath_inflate(void *data, u_int16_t len, u_int16_t *newlen)
{
	u_int8_t	*seg, *nseg, *ndata;
	u_int16_t	 seg_size, olen, nlen;
	u_int8_t	 seg_len;

	/* first calculate the length of the aspath */
	seg = data;
	nlen = 0;
	for (olen = len; olen > 0; olen -= seg_size, seg += seg_size) {
		seg_len = seg[1];
		seg_size = 2 + sizeof(u_int16_t) * seg_len;
		nlen += 2 + sizeof(u_int32_t) * seg_len;

		if (seg_size > olen)
			return NULL;
	}

	*newlen = nlen;
	if ((ndata = malloc(nlen)) == NULL)
		err(1, "malloc");

	/* then copy the aspath */
	seg = data;
	for (nseg = ndata; nseg < ndata + nlen; ) {
		*nseg++ = *seg++;
		*nseg++ = seg_len = *seg++;
		for (; seg_len > 0; seg_len--) {
			*nseg++ = 0;
			*nseg++ = 0;
			*nseg++ = *seg++;
			*nseg++ = *seg++;
		}
	}

	return (ndata);
}

int
mrt_extract_addr(void *msg, u_int len, struct bgpd_addr *addr, u_int8_t aid)
{
	u_int8_t	*b = msg;

	memset(addr, 0, sizeof(*addr));
	switch (aid) {
	case AID_INET:
		if (len < sizeof(struct in_addr))
			return (-1);
		addr->aid = aid;
		memcpy(&addr->v4, b, sizeof(struct in_addr));
		return sizeof(struct in_addr);
	case AID_INET6:
		if (len < sizeof(struct in6_addr))
			return (-1);
		addr->aid = aid;
		memcpy(&addr->v6, b, sizeof(struct in6_addr));
		return sizeof(struct in6_addr);
	case AID_VPN_IPv4:
		if (len < sizeof(u_int64_t) + sizeof(struct in_addr))
			return (-1);
		addr->aid = aid;
		/* XXX labelstack and rd missing */
		memcpy(&addr->v4, b + sizeof(u_int64_t),
		    sizeof(struct in_addr));
		return (sizeof(u_int64_t) + sizeof(struct in_addr));
	case AID_VPN_IPv6:
		if (len < sizeof(u_int64_t) + sizeof(struct in6_addr))
			return (-1);
		addr->aid = aid;
		/* XXX labelstack and rd missing */
		memcpy(&addr->v6, b + sizeof(u_int64_t),
		    sizeof(struct in6_addr));
		return (sizeof(u_int64_t) + sizeof(struct in6_addr));
	default:
		return (-1);
	}
}

int
mrt_extract_prefix(void *msg, u_int len, u_int8_t aid,
    struct bgpd_addr *prefix, u_int8_t *prefixlen, int verbose)
{
	int r;

	switch (aid) {
	case AID_INET:
		r = nlri_get_prefix(msg, len, prefix, prefixlen);
		break;
	case AID_INET6:
		r = nlri_get_prefix6(msg, len, prefix, prefixlen);
		break;
	case AID_VPN_IPv4:
		r = nlri_get_vpn4(msg, len, prefix, prefixlen, 0);
		break;
	case AID_VPN_IPv6:
		r = nlri_get_vpn6(msg, len, prefix, prefixlen, 0);
		break;
	default:
		if (verbose)
			printf("unknown prefix AID %d\n", aid);
		return -1;
	}
	if (r == -1 && verbose)
		printf("failed to parse prefix of AID %d\n", aid);
	return r;
}

struct mrt_bgp_state *
mrt_parse_state(struct mrt_hdr *hdr, void *msg, int verbose)
{
	struct timespec		 t;
	struct mrt_bgp_state	*s;
	u_int8_t		*b = msg;
	u_int			 len = ntohl(hdr->length);
	u_int32_t		 sas, das, usec;
	u_int16_t		 tmp16, afi;
	int			 r;
	u_int8_t		 aid;

	t.tv_sec = ntohl(hdr->timestamp);
	t.tv_nsec = 0;

	/* handle the microsec field for _ET header */
	if (ntohs(hdr->type) == MSG_PROTOCOL_BGP4MP_ET) {
		memcpy(&usec, b, sizeof(usec));
		b += sizeof(usec);
		len -= sizeof(usec);
		t.tv_nsec = ntohl(usec) * 1000;
	}

	switch (ntohs(hdr->subtype)) {
	case BGP4MP_STATE_CHANGE:
		if (len < 8)
			return (0);
		/* source as */
		memcpy(&tmp16, b, sizeof(tmp16));
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		sas = ntohs(tmp16);
		/* dest as */
		memcpy(&tmp16, b, sizeof(tmp16));
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		das = ntohs(tmp16);
		/* if_index, ignored */
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		/* afi */
		memcpy(&tmp16, b, sizeof(tmp16));
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		afi = ntohs(tmp16);
		break;
	case BGP4MP_STATE_CHANGE_AS4:
		if (len < 12)
			return (0);
		/* source as */
		memcpy(&sas, b, sizeof(sas));
		b += sizeof(sas);
		len -= sizeof(sas);
		sas = ntohl(sas);
		/* dest as */
		memcpy(&das, b, sizeof(das));
		b += sizeof(das);
		len -= sizeof(das);
		das = ntohl(das);
		/* if_index, ignored */
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		/* afi */
		memcpy(&tmp16, b, sizeof(tmp16));
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		afi = ntohs(tmp16);
		break;
	default:
		errx(1, "mrt_parse_state: bad subtype");
	}

	/* src & dst addr */
	if ((aid = mrt_afi2aid(afi, -1, verbose)) == AID_UNSPEC)
		return (NULL);

	if ((s = calloc(1, sizeof(struct mrt_bgp_state))) == NULL)
		err(1, "calloc");
	s->time = t;
	s->src_as = sas;
	s->dst_as = das;

	if ((r = mrt_extract_addr(b, len, &s->src, aid)) == -1)
		goto fail;
	b += r;
	len -= r;
	if ((r = mrt_extract_addr(b, len, &s->dst, aid)) == -1)
		goto fail;
	b += r;
	len -= r;

	/* states */
	memcpy(&tmp16, b, sizeof(tmp16));
	b += sizeof(tmp16);
	len -= sizeof(tmp16);
	s->old_state = ntohs(tmp16);
	memcpy(&tmp16, b, sizeof(tmp16));
	b += sizeof(tmp16);
	len -= sizeof(tmp16);
	s->new_state = ntohs(tmp16);

	return (s);

fail:
	free(s);
	return (NULL);
}

struct mrt_bgp_msg *
mrt_parse_msg(struct mrt_hdr *hdr, void *msg, int verbose)
{
	struct timespec		 t;
	struct mrt_bgp_msg	*m;
	u_int8_t		*b = msg;
	u_int			 len = ntohl(hdr->length);
	u_int32_t		 sas, das, usec;
	u_int16_t		 tmp16, afi;
	int			 r, addpath = 0;
	u_int8_t		 aid;

	t.tv_sec = ntohl(hdr->timestamp);
	t.tv_nsec = 0;

	/* handle the microsec field for _ET header */
	if (ntohs(hdr->type) == MSG_PROTOCOL_BGP4MP_ET) {
		memcpy(&usec, b, sizeof(usec));
		b += sizeof(usec);
		len -= sizeof(usec);
		t.tv_nsec = ntohl(usec) * 1000;
	}

	switch (ntohs(hdr->subtype)) {
	case BGP4MP_MESSAGE_ADDPATH:
	case BGP4MP_MESSAGE_LOCAL_ADDPATH:
		addpath = 1;
		/* FALLTHROUGH */
	case BGP4MP_MESSAGE:
	case BGP4MP_MESSAGE_LOCAL:
		if (len < 8)
			return (0);
		/* source as */
		memcpy(&tmp16, b, sizeof(tmp16));
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		sas = ntohs(tmp16);
		/* dest as */
		memcpy(&tmp16, b, sizeof(tmp16));
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		das = ntohs(tmp16);
		/* if_index, ignored */
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		/* afi */
		memcpy(&tmp16, b, sizeof(tmp16));
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		afi = ntohs(tmp16);
		break;
	case BGP4MP_MESSAGE_AS4_ADDPATH:
	case BGP4MP_MESSAGE_AS4_LOCAL_ADDPATH:
		addpath = 1;
		/* FALLTHROUGH */
	case BGP4MP_MESSAGE_AS4:
	case BGP4MP_MESSAGE_AS4_LOCAL:
		if (len < 12)
			return (0);
		/* source as */
		memcpy(&sas, b, sizeof(sas));
		b += sizeof(sas);
		len -= sizeof(sas);
		sas = ntohl(sas);
		/* dest as */
		memcpy(&das, b, sizeof(das));
		b += sizeof(das);
		len -= sizeof(das);
		das = ntohl(das);
		/* if_index, ignored */
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		/* afi */
		memcpy(&tmp16, b, sizeof(tmp16));
		b += sizeof(tmp16);
		len -= sizeof(tmp16);
		afi = ntohs(tmp16);
		break;
	default:
		errx(1, "mrt_parse_msg: bad subtype");
	}

	/* src & dst addr */
	if ((aid = mrt_afi2aid(afi, -1, verbose)) == AID_UNSPEC)
		return (NULL);

	if ((m = calloc(1, sizeof(struct mrt_bgp_msg))) == NULL)
		err(1, "calloc");
	m->time = t;
	m->src_as = sas;
	m->dst_as = das;
	m->add_path = addpath;

	if ((r = mrt_extract_addr(b, len, &m->src, aid)) == -1)
		goto fail;
	b += r;
	len -= r;
	if ((r = mrt_extract_addr(b, len, &m->dst, aid)) == -1)
		goto fail;
	b += r;
	len -= r;

	/* msg */
	if (len > 0) {
		m->msg_len = len;
		if ((m->msg = malloc(len)) == NULL)
			err(1, "malloc");
		memcpy(m->msg, b, len);
	}

	return (m);

fail:
	free(m->msg);
	free(m);
	return (NULL);
}
IABSD.fr/src/usr.sbin/bgpctl/mrtparser.c

Commit

IABSD.fr/src /usr.sbin/bgpctl/mrtparser.c
