OpenBSD-4.6/usr.sbin/ospf6d/packet.c
/* $OpenBSD: packet.c,v 1.9 2008/03/24 16:11:04 deraadt Exp $ */
/*
* Copyright (c) 2004, 2005 Esben Norby <norby@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 <sys/uio.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <arpa/inet.h>
#include <net/if_dl.h>
#include <errno.h>
#include <event.h>
#include <stdlib.h>
#include <string.h>
#include "ospf6d.h"
#include "ospf6.h"
#include "log.h"
#include "ospfe.h"
int ip_hdr_sanity_check(const struct ip6_hdr *, u_int16_t);
int ospf_hdr_sanity_check(struct ospf_hdr *, u_int16_t,
const struct iface *, struct in6_addr *);
struct iface *find_iface(struct ospfd_conf *, unsigned int,
struct in6_addr *);
int
gen_ospf_hdr(struct buf *buf, struct iface *iface, u_int8_t type)
{
struct ospf_hdr ospf_hdr;
bzero(&ospf_hdr, sizeof(ospf_hdr));
ospf_hdr.version = OSPF6_VERSION;
ospf_hdr.type = type;
ospf_hdr.rtr_id = ospfe_router_id();
if (iface->type != IF_TYPE_VIRTUALLINK)
ospf_hdr.area_id = iface->area_id.s_addr;
ospf_hdr.instance = DEFAULT_INSTANCE_ID;
ospf_hdr.zero = 0; /* must be zero */
return (buf_add(buf, &ospf_hdr, sizeof(ospf_hdr)));
}
int
upd_ospf_hdr(struct buf *buf, struct iface *iface)
{
struct ospf_hdr *ospf_hdr;
if ((ospf_hdr = buf_seek(buf, 0, sizeof(ospf_hdr))) == NULL)
fatalx("upd_ospf_hdr: buf_seek failed");
/* update length */
if (buf->wpos > USHRT_MAX)
fatalx("upd_ospf_hdr: resulting ospf packet too big");
ospf_hdr->len = htons((u_int16_t)buf->wpos);
ospf_hdr->chksum = 0; /* calculated via IPV6_CHECKSUM */
return (0);
}
/* send and receive packets */
int
send_packet(struct iface *iface, void *pkt, size_t len,
struct in6_addr *dst)
{
struct sockaddr_in6 sa6;
/* setup buffer */
bzero(&sa6, sizeof(sa6));
sa6.sin6_family = AF_INET6;
sa6.sin6_len = sizeof(sa6);
sa6.sin6_addr = *dst;
/* don't we all love link local scope and all the needed hacks for it */
if (IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst))
sa6.sin6_scope_id = iface->ifindex;
/* set outgoing interface for multicast traffic */
if (IN6_IS_ADDR_MULTICAST(dst))
if (if_set_mcast(iface) == -1) {
log_warn("send_packet: error setting multicast "
"interface, %s", iface->name);
return (-1);
}
if (sendto(iface->fd, pkt, len, MSG_DONTROUTE, (struct sockaddr *)&sa6,
sizeof(sa6)) == -1) {
log_warn("send_packet: error sending packet on interface %s",
iface->name);
return (-1);
}
return (0);
}
void
recv_packet(int fd, short event, void *bula)
{
union {
struct cmsghdr hdr;
char buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
} cmsgbuf;
struct msghdr msg;
struct iovec iov;
struct in6_addr addr, dest;
struct sockaddr_in6 src;
struct ospfd_conf *xconf = bula;
struct ospf_hdr *ospf_hdr;
struct iface *iface;
struct nbr *nbr = NULL;
char *buf;
struct cmsghdr *cmsg;
ssize_t r;
u_int16_t len;
int l;
unsigned int ifindex = 0;
if (event != EV_READ)
return;
/* setup buffer */
bzero(&msg, sizeof(msg));
iov.iov_base = buf = pkt_ptr;
iov.iov_len = READ_BUF_SIZE;
msg.msg_name = &src;
msg.msg_namelen = sizeof(src);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = &cmsgbuf.buf;
msg.msg_controllen = sizeof(cmsgbuf.buf);
if ((r = recvmsg(fd, &msg, 0)) == -1) {
if (errno != EAGAIN && errno != EINTR)
log_debug("recv_packet: read error: %s",
strerror(errno));
return;
}
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == IPPROTO_IPV6 &&
cmsg->cmsg_type == IPV6_PKTINFO) {
ifindex = ((struct in6_pktinfo *)
CMSG_DATA(cmsg))->ipi6_ifindex;
dest = ((struct in6_pktinfo *)
CMSG_DATA(cmsg))->ipi6_addr;
break;
}
}
/* find a matching interface */
if ((iface = find_iface(xconf, ifindex, &src.sin6_addr)) == NULL) {
/* XXX add a counter here */
return;
}
/*
* Packet needs to be sent to AllSPFRouters or AllDRouters
* or to the address of the interface itself.
* AllDRouters is only valid for DR and BDR but this is checked later.
*/
inet_pton(AF_INET6, AllSPFRouters, &addr);
if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) {
inet_pton(AF_INET6, AllDRouters, &addr);
if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) {
if (!IN6_ARE_ADDR_EQUAL(&dest, &iface->addr)) {
log_debug("recv_packet: packet sent to wrong "
"address %s, interface %s",
log_in6addr(&dest), iface->name);
return;
}
}
}
len = (u_int16_t)r;
/* OSPF header sanity checks */
if (len < sizeof(*ospf_hdr)) {
log_debug("recv_packet: bad packet size");
return;
}
ospf_hdr = (struct ospf_hdr *)buf;
if ((l = ospf_hdr_sanity_check(ospf_hdr, len, iface, &dest)) == -1)
return;
nbr = nbr_find_id(iface, ospf_hdr->rtr_id);
if (ospf_hdr->type != PACKET_TYPE_HELLO && nbr == NULL) {
log_debug("recv_packet: unknown neighbor ID");
return;
}
buf += sizeof(*ospf_hdr);
len = l - sizeof(*ospf_hdr);
/* switch OSPF packet type */
switch (ospf_hdr->type) {
case PACKET_TYPE_HELLO:
inet_pton(AF_INET6, AllDRouters, &addr);
if (IN6_ARE_ADDR_EQUAL(&dest, &addr)) {
log_debug("recv_packet: invalid destination IP "
"address");
break;
}
recv_hello(iface, &src.sin6_addr, ospf_hdr->rtr_id, buf, len);
break;
case PACKET_TYPE_DD:
recv_db_description(nbr, buf, len);
break;
case PACKET_TYPE_LS_REQUEST:
recv_ls_req(nbr, buf, len);
break;
case PACKET_TYPE_LS_UPDATE:
recv_ls_update(nbr, buf, len);
break;
case PACKET_TYPE_LS_ACK:
recv_ls_ack(nbr, buf, len);
break;
default:
log_debug("recv_packet: unknown OSPF packet type, interface %s",
iface->name);
}
}
int
ospf_hdr_sanity_check(struct ospf_hdr *ospf_hdr, u_int16_t len,
const struct iface *iface, struct in6_addr *dst)
{
struct in6_addr addr;
struct in_addr id;
if (ospf_hdr->version != OSPF6_VERSION) {
log_debug("recv_packet: invalid OSPF version %d",
ospf_hdr->version);
return (-1);
}
if (ntohs(ospf_hdr->len) > len ||
len <= sizeof(struct ospf_hdr)) {
log_debug("recv_packet: invalid OSPF packet length %d",
ntohs(ospf_hdr->len));
return (-1);
}
if (iface->type != IF_TYPE_VIRTUALLINK) {
if (ospf_hdr->area_id != iface->area_id.s_addr) {
id.s_addr = ospf_hdr->area_id;
log_debug("recv_packet: invalid area ID %s, "
"interface %s", inet_ntoa(id), iface->name);
return (-1);
}
} else {
if (ospf_hdr->area_id != 0) {
id.s_addr = ospf_hdr->area_id;
log_debug("recv_packet: invalid area ID %s, "
"interface %s", inet_ntoa(id), iface->name);
return (-1);
}
}
if (iface->type == IF_TYPE_BROADCAST || iface->type == IF_TYPE_NBMA) {
if (inet_pton(AF_INET6, AllDRouters, &addr) == 0)
fatalx("recv_packet: inet_pton");
if (IN6_ARE_ADDR_EQUAL(dst, &addr) &&
(iface->state & IF_STA_DRORBDR) == 0) {
log_debug("recv_packet: invalid destination IP in "
"state %s, interface %s",
if_state_name(iface->state), iface->name);
return (-1);
}
}
return (ntohs(ospf_hdr->len));
}
struct iface *
find_iface(struct ospfd_conf *xconf, unsigned int ifindex, struct in6_addr *src)
{
struct area *area;
struct iface *iface, *match = NULL;
/*
* Returned interface needs to be active.
* Virtual-Links have higher precedence so the full interface
* list needs to be scanned for possible matches.
*/
LIST_FOREACH(area, &xconf->area_list, entry) {
LIST_FOREACH(iface, &area->iface_list, entry) {
switch (iface->type) {
case IF_TYPE_VIRTUALLINK:
if (IN6_ARE_ADDR_EQUAL(src, &iface->dst) &&
!(iface->cflags & F_IFACE_PASSIVE))
return (iface);
break;
default:
if (ifindex == iface->ifindex &&
!(iface->cflags & F_IFACE_PASSIVE))
match = iface;
break;
}
}
}
return (match);
}