[mirror_frr.git] / vrrpd / vrrp_packet.c

/*
 * VRRP packet crafting.
 * Copyright (C) 2018-2019 Cumulus Networks, Inc.
 * Quentin Young
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include <zebra.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>

#include "lib/checksum.h"
#include "lib/ipaddr.h"
#include "lib/memory.h"

#include "vrrp.h"
#include "vrrp_debug.h"
#include "vrrp_packet.h"

DEFINE_MTYPE_STATIC(VRRPD, VRRP_PKT, "VRRP packet")

/* clang-format off */
static const char *const vrrp_packet_names[16] = {
	[0] = "Unknown",
	[VRRP_TYPE_ADVERTISEMENT] = "ADVERTISEMENT",
	[2] = "Unknown",
	[3] = "Unknown",
	[4] = "Unknown",
	[5] = "Unknown",
	[6] = "Unknown",
	[7] = "Unknown",
	[8] = "Unknown",
	[9] = "Unknown",
	[10] = "Unknown",
	[11] = "Unknown",
	[12] = "Unknown",
	[13] = "Unknown",
	[14] = "Unknown",
	[15] = "Unknown",
};
/* clang-format on */

/*
 * Compute the VRRP checksum.
 *
 * Checksum is not set in the packet, just computed.
 *
 * pkt
 *    VRRP packet, fully filled out except for checksum field.
 *
 * pktsize
 *    sizeof(*pkt)
 *
 * src
 *    IP address that pkt will be transmitted from.
 *
 * Returns:
 *    VRRP checksum in network byte order.
 */
static uint16_t vrrp_pkt_checksum(struct vrrp_pkt *pkt, size_t pktsize,
				  struct ipaddr *src)
{
	uint16_t chksum;
	bool v6 = (src->ipa_type == IPADDR_V6);

	uint16_t chksum_pre = pkt->hdr.chksum;

	pkt->hdr.chksum = 0;

	if (v6) {
		struct ipv6_ph ph = {};

		ph.src = src->ipaddr_v6;
		inet_pton(AF_INET6, VRRP_MCASTV6_GROUP_STR, &ph.dst);
		ph.ulpl = htons(pktsize);
		ph.next_hdr = IPPROTO_VRRP;
		chksum = in_cksum_with_ph6(&ph, pkt, pktsize);
	} else if (!v6 && ((pkt->hdr.vertype >> 4) == 3)) {
		struct ipv4_ph ph = {};

		ph.src = src->ipaddr_v4;
		inet_pton(AF_INET, VRRP_MCASTV4_GROUP_STR, &ph.dst);
		ph.proto = IPPROTO_VRRP;
		ph.len = htons(pktsize);
		chksum = in_cksum_with_ph4(&ph, pkt, pktsize);
	} else if (!v6 && ((pkt->hdr.vertype >> 4) == 2)) {
		chksum = in_cksum(pkt, pktsize);
	} else {
		assert(!"Invalid VRRP protocol version");
	}

	pkt->hdr.chksum = chksum_pre;

	return chksum;
}

ssize_t vrrp_pkt_adver_build(struct vrrp_pkt **pkt, struct ipaddr *src,
			     uint8_t version, uint8_t vrid, uint8_t prio,
			     uint16_t max_adver_int, uint8_t numip,
			     struct ipaddr **ips)
{
	bool v6 = false;
	size_t addrsz = 0;

	assert(version >= 2 && version <= 3);

	if (numip > 0) {
		v6 = IS_IPADDR_V6(ips[0]);
		addrsz = IPADDRSZ(ips[0]);
	}

	assert(!(version == 2 && v6));

	size_t pktsize = VRRP_PKT_SIZE(v6 ? AF_INET6 : AF_INET, version, numip);

	*pkt = XCALLOC(MTYPE_VRRP_PKT, pktsize);

	(*pkt)->hdr.vertype |= version << 4;
	(*pkt)->hdr.vertype |= VRRP_TYPE_ADVERTISEMENT;
	(*pkt)->hdr.vrid = vrid;
	(*pkt)->hdr.priority = prio;
	(*pkt)->hdr.naddr = numip;
	if (version == 3)
		(*pkt)->hdr.v3.adver_int = htons(max_adver_int);
	else if (version == 2) {
		(*pkt)->hdr.v2.auth_type = 0;
		(*pkt)->hdr.v2.adver_int = MAX(max_adver_int / 100, 1);
	}

	uint8_t *aptr = (void *)(*pkt)->addrs;

	for (int i = 0; i < numip; i++) {
		memcpy(aptr, &ips[i]->ip.addr, addrsz);
		aptr += addrsz;
	}

	(*pkt)->hdr.chksum = vrrp_pkt_checksum(*pkt, pktsize, src);

	return pktsize;
}

void vrrp_pkt_free(struct vrrp_pkt *pkt)
{
	XFREE(MTYPE_VRRP_PKT, pkt);
}

size_t vrrp_pkt_adver_dump(char *buf, size_t buflen, struct vrrp_pkt *pkt)
{
	if (buflen < 1)
		return 0;

	char tmpbuf[BUFSIZ];
	size_t rs = 0;
	struct vrrp_hdr *hdr = &pkt->hdr;

	buf[0] = 0x00;
	snprintf(tmpbuf, sizeof(tmpbuf), "version %u, ", (hdr->vertype >> 4));
	rs += strlcat(buf, tmpbuf, buflen);
	snprintf(tmpbuf, sizeof(tmpbuf), "type %u (%s), ",
		 (hdr->vertype & 0x0F),
		 vrrp_packet_names[(hdr->vertype & 0x0F)]);
	rs += strlcat(buf, tmpbuf, buflen);
	snprintf(tmpbuf, sizeof(tmpbuf), "vrid %u, ", hdr->vrid);
	rs += strlcat(buf, tmpbuf, buflen);
	snprintf(tmpbuf, sizeof(tmpbuf), "priority %u, ", hdr->priority);
	rs += strlcat(buf, tmpbuf, buflen);
	snprintf(tmpbuf, sizeof(tmpbuf), "#%u addresses, ", hdr->naddr);
	rs += strlcat(buf, tmpbuf, buflen);
	snprintf(tmpbuf, sizeof(tmpbuf), "max adver int %u, ",
		 ntohs(hdr->v3.adver_int));
	rs += strlcat(buf, tmpbuf, buflen);
	snprintf(tmpbuf, sizeof(tmpbuf), "checksum %x", ntohs(hdr->chksum));
	rs += strlcat(buf, tmpbuf, buflen);

	return rs;
}

ssize_t vrrp_pkt_parse_datagram(int family, int version, struct msghdr *m,
				size_t read, struct ipaddr *src,
				struct vrrp_pkt **pkt, char *errmsg,
				size_t errmsg_len)
{
	/* Source (MAC & IP), Dest (MAC & IP) TTL validation done by kernel */
	size_t addrsz = (family == AF_INET) ? sizeof(struct in_addr)
					    : sizeof(struct in6_addr);

	size_t pktsize;
	uint8_t *buf = m->msg_iov->iov_base;

#define VRRP_PKT_VCHECK(cond, _f, ...)                                         \
	do {                                                                   \
		if (!(cond)) {                                                 \
			if (errmsg)                                            \
				snprintf(errmsg, errmsg_len, (_f),             \
					 ##__VA_ARGS__);                       \
			return -1;                                             \
		}                                                              \
	} while (0)

	/* IPvX header check */

	if (family == AF_INET) {
		VRRP_PKT_VCHECK(
			read >= sizeof(struct ip),
			"Datagram not large enough to contain IP header");

		struct ip *ip = (struct ip *)buf;

		/* IP total length check */
		VRRP_PKT_VCHECK(
			ntohs(ip->ip_len) == read,
			"IPv4 packet length field does not match # received bytes; %" PRIu16
			"!= %zu",
			ntohs(ip->ip_len), read);

		/* TTL check */
		VRRP_PKT_VCHECK(ip->ip_ttl == 255,
				"IPv4 TTL is %" PRIu8 "; should be 255",
				ip->ip_ttl);

		*pkt = (struct vrrp_pkt *)(buf + (ip->ip_hl << 2));
		pktsize = read - (ip->ip_hl << 2);

		/* IP empty packet check */
		VRRP_PKT_VCHECK(pktsize > 0, "IPv4 packet has no payload");

		/* Extract source address */
		struct sockaddr_in *sa = m->msg_name;

		src->ipa_type = IPADDR_V4;
		src->ipaddr_v4 = sa->sin_addr;
	} else if (family == AF_INET6) {
		struct cmsghdr *c;

		for (c = CMSG_FIRSTHDR(m); c != NULL; CMSG_NXTHDR(m, c)) {
			if (c->cmsg_level == IPPROTO_IPV6
			    && c->cmsg_type == IPV6_HOPLIMIT)
				break;
		}

		VRRP_PKT_VCHECK(!!c, "IPv6 Hop Limit not received");

		uint8_t *hoplimit = CMSG_DATA(c);

		VRRP_PKT_VCHECK(*hoplimit == 255,
				"IPv6 Hop Limit is %" PRIu8 "; should be 255",
				*hoplimit);

		*pkt = (struct vrrp_pkt *)buf;
		pktsize = read;

		/* Extract source address */
		struct sockaddr_in6 *sa = m->msg_name;

		src->ipa_type = IPADDR_V6;
		memcpy(&src->ipaddr_v6, &sa->sin6_addr,
		       sizeof(struct in6_addr));
	} else {
		assert(!"Unknown address family");
	}

	/* Size check */
	size_t minsize = (family == AF_INET) ? VRRP_MIN_PKT_SIZE_V4
					     : VRRP_MIN_PKT_SIZE_V6;
	size_t maxsize = (family == AF_INET) ? VRRP_MAX_PKT_SIZE_V4
					     : VRRP_MAX_PKT_SIZE_V6;
	VRRP_PKT_VCHECK(pktsize >= minsize,
			"VRRP packet is undersized (%zu < %zu)", pktsize,
			minsize);
	VRRP_PKT_VCHECK(pktsize <= maxsize,
			"VRRP packet is oversized (%zu > %zu)", pktsize,
			maxsize);

	/* Version check */
	uint8_t pktver = (*pkt)->hdr.vertype >> 4;

	VRRP_PKT_VCHECK(pktver == version, "Bad version %u", pktver);

	/* Checksum check */
	uint16_t chksum = vrrp_pkt_checksum(*pkt, pktsize, src);

	VRRP_PKT_VCHECK((*pkt)->hdr.chksum == chksum,
			"Bad VRRP checksum %" PRIx16 "; should be %" PRIx16 "",
			(*pkt)->hdr.chksum, chksum);

	/* Type check */
	VRRP_PKT_VCHECK(((*pkt)->hdr.vertype & 0x0F) == 1, "Bad type %" PRIu8,
			(*pkt)->hdr.vertype & 0x0f);

	/* Exact size check */
	size_t ves = VRRP_PKT_SIZE(family, pktver, (*pkt)->hdr.naddr);

	VRRP_PKT_VCHECK(pktsize == ves, "Packet has incorrect # addresses%s",
			pktver == 2 ? " or missing auth fields" : "");

	/* auth type check */
	if (version == 2)
		VRRP_PKT_VCHECK((*pkt)->hdr.v2.auth_type == 0,
				"Bad authentication type %" PRIu8,
				(*pkt)->hdr.v2.auth_type);

	/* Addresses check */
	char vbuf[INET6_ADDRSTRLEN];
	uint8_t *p = (uint8_t *)(*pkt)->addrs;

	for (uint8_t i = 0; i < (*pkt)->hdr.naddr; i++) {
		VRRP_PKT_VCHECK(inet_ntop(family, p, vbuf, sizeof(vbuf)),
				"Bad IP address, #%" PRIu8, i);
		p += addrsz;
	}

	/* Everything checks out */
	return pktsize;
}
Commit	Line	Data
5435a2bf	1	/*
63d4bd12 QY	2	* VRRP packet crafting.
	3	* Copyright (C) 2018-2019 Cumulus Networks, Inc.
	4	* Quentin Young
5435a2bf QY	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License as published by the Free
	8	* Software Foundation; either version 2 of the License, or (at your option)
	9	* any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful, but WITHOUT
	12	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	13	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	14	* more details.
	15	*
	16	* You should have received a copy of the GNU General Public License along
	17	* with this program; see the file COPYING; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	19	*/
	20	#include <zebra.h>
91188ca6 QY	21	#include <netinet/in.h>
	22	#include <netinet/ip.h>
	23	#include <netinet/ip6.h>
5435a2bf	24
3eca3857	25	#include "lib/checksum.h"
91188ca6 QY	26	#include "lib/ipaddr.h"
91188ca6 QY	27	#include "lib/memory.h"
5435a2bf	28
8071d5c3	29	#include "vrrp.h"
b637bcd4	30	#include "vrrp_debug.h"
5435a2bf QY	31	#include "vrrp_packet.h"
5435a2bf QY	32
7c136b08 DL	33	DEFINE_MTYPE_STATIC(VRRPD, VRRP_PKT, "VRRP packet")
7c136b08 DL	34
91188ca6	35	/* clang-format off */
2b64873d	36	static const char *const vrrp_packet_names[16] = {
91188ca6 QY	37	[0] = "Unknown",
	38	[VRRP_TYPE_ADVERTISEMENT] = "ADVERTISEMENT",
	39	[2] = "Unknown",
	40	[3] = "Unknown",
	41	[4] = "Unknown",
	42	[5] = "Unknown",
	43	[6] = "Unknown",
	44	[7] = "Unknown",
	45	[8] = "Unknown",
	46	[9] = "Unknown",
	47	[10] = "Unknown",
	48	[11] = "Unknown",
	49	[12] = "Unknown",
	50	[13] = "Unknown",
	51	[14] = "Unknown",
	52	[15] = "Unknown",
	53	};
	54	/* clang-format on */
	55
d9e01e1c QY	56	/*
	57	* Compute the VRRP checksum.
	58	*
	59	* Checksum is not set in the packet, just computed.
	60	*
	61	* pkt
	62	* VRRP packet, fully filled out except for checksum field.
	63	*
	64	* pktsize
	65	* sizeof(*pkt)
	66	*
	67	* src
	68	* IP address that pkt will be transmitted from.
	69	*
	70	* Returns:
	71	* VRRP checksum in network byte order.
	72	*/
	73	static uint16_t vrrp_pkt_checksum(struct vrrp_pkt *pkt, size_t pktsize,
	74	struct ipaddr *src)
	75	{
	76	uint16_t chksum;
	77	bool v6 = (src->ipa_type == IPADDR_V6);
	78
	79	uint16_t chksum_pre = pkt->hdr.chksum;
2fff50ec	80
d9e01e1c QY	81	pkt->hdr.chksum = 0;
	82
	83	if (v6) {
	84	struct ipv6_ph ph = {};
2fff50ec	85
d9e01e1c QY	86	ph.src = src->ipaddr_v6;
	87	inet_pton(AF_INET6, VRRP_MCASTV6_GROUP_STR, &ph.dst);
	88	ph.ulpl = htons(pktsize);
723123f3	89	ph.next_hdr = IPPROTO_VRRP;
d9e01e1c	90	chksum = in_cksum_with_ph6(&ph, pkt, pktsize);
99966840	91	} else if (!v6 && ((pkt->hdr.vertype >> 4) == 3)) {
d9e01e1c	92	struct ipv4_ph ph = {};
2fff50ec	93
d9e01e1c QY	94	ph.src = src->ipaddr_v4;
d9e01e1c QY	95	inet_pton(AF_INET, VRRP_MCASTV4_GROUP_STR, &ph.dst);
723123f3	96	ph.proto = IPPROTO_VRRP;
d9e01e1c QY	97	ph.len = htons(pktsize);
d9e01e1c QY	98	chksum = in_cksum_with_ph4(&ph, pkt, pktsize);
99966840 QY	99	} else if (!v6 && ((pkt->hdr.vertype >> 4) == 2)) {
	100	chksum = in_cksum(pkt, pktsize);
	101	} else {
	102	assert(!"Invalid VRRP protocol version");
d9e01e1c QY	103	}
	104
	105	pkt->hdr.chksum = chksum_pre;
	106
	107	return chksum;
	108	}
	109
	110	ssize_t vrrp_pkt_adver_build(struct vrrp_pkt *pkt, struct ipaddr src,
	111	uint8_t version, uint8_t vrid, uint8_t prio,
	112	uint16_t max_adver_int, uint8_t numip,
	113	struct ipaddr **ips)
5435a2bf	114	{
3d55d467 QY	115	bool v6 = false;
3d55d467 QY	116	size_t addrsz = 0;
3eca3857	117
99966840	118	assert(version >= 2 && version <= 3);
99966840	119
3d55d467 QY	120	if (numip > 0) {
	121	v6 = IS_IPADDR_V6(ips[0]);
	122	addrsz = IPADDRSZ(ips[0]);
	123	}
	124
e1a32d76 QY	125	assert(!(version == 2 && v6));
e1a32d76 QY	126
c2034b25	127	size_t pktsize = VRRP_PKT_SIZE(v6 ? AF_INET6 : AF_INET, version, numip);
2fff50ec	128
72df9d93	129	*pkt = XCALLOC(MTYPE_VRRP_PKT, pktsize);
3eca3857	130
d9e01e1c	131	(*pkt)->hdr.vertype \|= version << 4;
3eca3857 QY	132	(*pkt)->hdr.vertype \|= VRRP_TYPE_ADVERTISEMENT;
	133	(*pkt)->hdr.vrid = vrid;
	134	(*pkt)->hdr.priority = prio;
	135	(*pkt)->hdr.naddr = numip;
99966840 QY	136	if (version == 3)
	137	(*pkt)->hdr.v3.adver_int = htons(max_adver_int);
	138	else if (version == 2) {
	139	(*pkt)->hdr.v2.auth_type = 0;
	140	(*pkt)->hdr.v2.adver_int = MAX(max_adver_int / 100, 1);
	141	}
3eca3857	142
862f2f37 QY	143	uint8_t aptr = (void )(*pkt)->addrs;
862f2f37 QY	144
3eca3857	145	for (int i = 0; i < numip; i++) {
862f2f37 QY	146	memcpy(aptr, &ips[i]->ip.addr, addrsz);
862f2f37 QY	147	aptr += addrsz;
3eca3857	148	}
8071d5c3	149
d9e01e1c	150	(pkt)->hdr.chksum = vrrp_pkt_checksum(pkt, pktsize, src);
3eca3857 QY	151
3eca3857 QY	152	return pktsize;
5435a2bf	153	}
91188ca6	154
7c136b08 DL	155	void vrrp_pkt_free(struct vrrp_pkt *pkt)
	156	{
	157	XFREE(MTYPE_VRRP_PKT, pkt);
	158	}
	159
d9e01e1c	160	size_t vrrp_pkt_adver_dump(char buf, size_t buflen, struct vrrp_pkt pkt)
91188ca6 QY	161	{
	162	if (buflen < 1)
	163	return 0;
	164
	165	char tmpbuf[BUFSIZ];
	166	size_t rs = 0;
	167	struct vrrp_hdr *hdr = &pkt->hdr;
	168
	169	buf[0] = 0x00;
613b45b0	170	snprintf(tmpbuf, sizeof(tmpbuf), "version %u, ", (hdr->vertype >> 4));
91188ca6	171	rs += strlcat(buf, tmpbuf, buflen);
613b45b0	172	snprintf(tmpbuf, sizeof(tmpbuf), "type %u (%s), ",
91188ca6 QY	173	(hdr->vertype & 0x0F),
	174	vrrp_packet_names[(hdr->vertype & 0x0F)]);
	175	rs += strlcat(buf, tmpbuf, buflen);
613b45b0	176	snprintf(tmpbuf, sizeof(tmpbuf), "vrid %u, ", hdr->vrid);
91188ca6	177	rs += strlcat(buf, tmpbuf, buflen);
613b45b0	178	snprintf(tmpbuf, sizeof(tmpbuf), "priority %u, ", hdr->priority);
91188ca6	179	rs += strlcat(buf, tmpbuf, buflen);
613b45b0	180	snprintf(tmpbuf, sizeof(tmpbuf), "#%u addresses, ", hdr->naddr);
91188ca6	181	rs += strlcat(buf, tmpbuf, buflen);
613b45b0	182	snprintf(tmpbuf, sizeof(tmpbuf), "max adver int %u, ",
91188ca6 QY	183	ntohs(hdr->v3.adver_int));
91188ca6 QY	184	rs += strlcat(buf, tmpbuf, buflen);
613b45b0	185	snprintf(tmpbuf, sizeof(tmpbuf), "checksum %x", ntohs(hdr->chksum));
91188ca6 QY	186	rs += strlcat(buf, tmpbuf, buflen);
	187
	188	return rs;
	189	}
	190
8cb3d803 QY	191	ssize_t vrrp_pkt_parse_datagram(int family, int version, struct msghdr *m,
	192	size_t read, struct ipaddr *src,
	193	struct vrrp_pkt *pkt, char errmsg,
	194	size_t errmsg_len)
91188ca6 QY	195	{
	196	/* Source (MAC & IP), Dest (MAC & IP) TTL validation done by kernel */
	197	size_t addrsz = (family == AF_INET) ? sizeof(struct in_addr)
	198	: sizeof(struct in6_addr);
	199
	200	size_t pktsize;
	201	uint8_t *buf = m->msg_iov->iov_base;
	202
	203	#define VRRP_PKT_VCHECK(cond, _f, ...) \
	204	do { \
	205	if (!(cond)) { \
	206	if (errmsg) \
	207	snprintf(errmsg, errmsg_len, (_f), \
	208	##__VA_ARGS__); \
	209	return -1; \
	210	} \
	211	} while (0)
	212
	213	/* IPvX header check */
	214
	215	if (family == AF_INET) {
	216	VRRP_PKT_VCHECK(
	217	read >= sizeof(struct ip),
	218	"Datagram not large enough to contain IP header");
	219
	220	struct ip ip = (struct ip )buf;
	221
	222	/* IP total length check */
	223	VRRP_PKT_VCHECK(
	224	ntohs(ip->ip_len) == read,
7e9fee6a QY	225	"IPv4 packet length field does not match # received bytes; %" PRIu16
7e9fee6a QY	226	"!= %zu",
91188ca6 QY	227	ntohs(ip->ip_len), read);
	228
	229	/* TTL check */
dad18a2f QY	230	VRRP_PKT_VCHECK(ip->ip_ttl == 255,
	231	"IPv4 TTL is %" PRIu8 "; should be 255",
	232	ip->ip_ttl);
91188ca6 QY	233
	234	pkt = (struct vrrp_pkt )(buf + (ip->ip_hl << 2));
	235	pktsize = read - (ip->ip_hl << 2);
	236
	237	/* IP empty packet check */
	238	VRRP_PKT_VCHECK(pktsize > 0, "IPv4 packet has no payload");
d04bb25a QY	239
d04bb25a QY	240	/* Extract source address */
fa211f1c	241	struct sockaddr_in *sa = m->msg_name;
2fff50ec	242
d04bb25a	243	src->ipa_type = IPADDR_V4;
fa211f1c	244	src->ipaddr_v4 = sa->sin_addr;
91188ca6 QY	245	} else if (family == AF_INET6) {
91188ca6 QY	246	struct cmsghdr *c;
2fff50ec	247
91188ca6 QY	248	for (c = CMSG_FIRSTHDR(m); c != NULL; CMSG_NXTHDR(m, c)) {
	249	if (c->cmsg_level == IPPROTO_IPV6
	250	&& c->cmsg_type == IPV6_HOPLIMIT)
	251	break;
	252	}
	253
	254	VRRP_PKT_VCHECK(!!c, "IPv6 Hop Limit not received");
	255
	256	uint8_t *hoplimit = CMSG_DATA(c);
2fff50ec	257
dad18a2f QY	258	VRRP_PKT_VCHECK(*hoplimit == 255,
	259	"IPv6 Hop Limit is %" PRIu8 "; should be 255",
	260	*hoplimit);
91188ca6 QY	261
	262	pkt = (struct vrrp_pkt )buf;
	263	pktsize = read;
d04bb25a QY	264
d04bb25a QY	265	/* Extract source address */
d04bb25a	266	struct sockaddr_in6 *sa = m->msg_name;
2fff50ec	267
fa211f1c	268	src->ipa_type = IPADDR_V6;
d04bb25a QY	269	memcpy(&src->ipaddr_v6, &sa->sin6_addr,
d04bb25a QY	270	sizeof(struct in6_addr));
91188ca6 QY	271	} else {
	272	assert(!"Unknown address family");
	273	}
	274
	275	/* Size check */
	276	size_t minsize = (family == AF_INET) ? VRRP_MIN_PKT_SIZE_V4
	277	: VRRP_MIN_PKT_SIZE_V6;
	278	size_t maxsize = (family == AF_INET) ? VRRP_MAX_PKT_SIZE_V4
	279	: VRRP_MAX_PKT_SIZE_V6;
	280	VRRP_PKT_VCHECK(pktsize >= minsize,
bb95fd82 QY	281	"VRRP packet is undersized (%zu < %zu)", pktsize,
bb95fd82 QY	282	minsize);
91188ca6	283	VRRP_PKT_VCHECK(pktsize <= maxsize,
bb95fd82 QY	284	"VRRP packet is oversized (%zu > %zu)", pktsize,
bb95fd82 QY	285	maxsize);
d04bb25a	286
8cb3d803 QY	287	/* Version check */
8cb3d803 QY	288	uint8_t pktver = (*pkt)->hdr.vertype >> 4;
2fff50ec	289
8cb3d803 QY	290	VRRP_PKT_VCHECK(pktver == version, "Bad version %u", pktver);
8cb3d803 QY	291
d04bb25a QY	292	/* Checksum check */
d04bb25a QY	293	uint16_t chksum = vrrp_pkt_checksum(*pkt, pktsize, src);
2fff50ec	294
d04bb25a	295	VRRP_PKT_VCHECK((*pkt)->hdr.chksum == chksum,
bb95fd82	296	"Bad VRRP checksum %" PRIx16 "; should be %" PRIx16 "",
d04bb25a QY	297	(*pkt)->hdr.chksum, chksum);
d04bb25a QY	298
91188ca6	299	/* Type check */
bb95fd82	300	VRRP_PKT_VCHECK(((*pkt)->hdr.vertype & 0x0F) == 1, "Bad type %" PRIu8,
91188ca6	301	(*pkt)->hdr.vertype & 0x0f);
8cb3d803	302
c2034b25 QY	303	/* Exact size check */
c2034b25 QY	304	size_t ves = VRRP_PKT_SIZE(family, pktver, (*pkt)->hdr.naddr);
2fff50ec	305
c2034b25 QY	306	VRRP_PKT_VCHECK(pktsize == ves, "Packet has incorrect # addresses%s",
c2034b25 QY	307	pktver == 2 ? " or missing auth fields" : "");
91188ca6	308
99966840 QY	309	/* auth type check */
	310	if (version == 2)
	311	VRRP_PKT_VCHECK((*pkt)->hdr.v2.auth_type == 0,
	312	"Bad authentication type %" PRIu8,
	313	(*pkt)->hdr.v2.auth_type);
	314
91188ca6 QY	315	/* Addresses check */
	316	char vbuf[INET6_ADDRSTRLEN];
	317	uint8_t p = (uint8_t )(*pkt)->addrs;
2fff50ec	318
91188ca6 QY	319	for (uint8_t i = 0; i < (*pkt)->hdr.naddr; i++) {
91188ca6 QY	320	VRRP_PKT_VCHECK(inet_ntop(family, p, vbuf, sizeof(vbuf)),
bb95fd82	321	"Bad IP address, #%" PRIu8, i);
91188ca6 QY	322	p += addrsz;
	323	}
	324
	325	/* Everything checks out */
	326	return pktsize;
	327	}