OpenBSD-4.6/usr.sbin/relayd/check_icmp.c
/* $OpenBSD: check_icmp.c,v 1.26 2008/12/05 16:37:55 reyk Exp $ */
/*
* Copyright (c) 2006 Pierre-Yves Ritschard <pyr@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/queue.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/icmp6.h>
#include <arpa/inet.h>
#include <limits.h>
#include <event.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <openssl/ssl.h>
#include "relayd.h"
void icmp_setup(struct relayd *, struct ctl_icmp_event *, int);
void check_icmp_add(struct ctl_icmp_event *, int, struct timeval *,
void (*)(int, short, void *));
int icmp_checks_done(struct ctl_icmp_event *);
void icmp_checks_timeout(struct ctl_icmp_event *, enum host_error);
void send_icmp(int, short, void *);
void recv_icmp(int, short, void *);
int in_cksum(u_short *, int);
void
icmp_setup(struct relayd *env, struct ctl_icmp_event *cie, int af)
{
int proto = IPPROTO_ICMP;
if (af == AF_INET6)
proto = IPPROTO_ICMPV6;
if ((cie->s = socket(af, SOCK_RAW, proto)) < 0)
fatal("icmp_init: socket");
session_socket_blockmode(cie->s, BM_NONBLOCK);
cie->env = env;
cie->af = af;
}
void
icmp_init(struct relayd *env)
{
icmp_setup(env, &env->sc_icmp_send, AF_INET);
icmp_setup(env, &env->sc_icmp_recv, AF_INET);
icmp_setup(env, &env->sc_icmp6_send, AF_INET6);
icmp_setup(env, &env->sc_icmp6_recv, AF_INET6);
env->sc_id = getpid() & 0xffff;
}
void
schedule_icmp(struct relayd *env, struct host *host)
{
host->last_up = host->up;
host->flags &= ~(F_CHECK_SENT|F_CHECK_DONE);
if (((struct sockaddr *)&host->conf.ss)->sa_family == AF_INET)
env->sc_has_icmp = 1;
else
env->sc_has_icmp6 = 1;
}
void
check_icmp_add(struct ctl_icmp_event *cie, int flags, struct timeval *start,
void (*fn)(int, short, void *))
{
struct timeval tv;
if (start != NULL)
bcopy(start, &cie->tv_start, sizeof(cie->tv_start));
bcopy(&cie->env->sc_timeout, &tv, sizeof(tv));
if (gettimeofday(&cie->tv_start, NULL) == -1)
fatal("check_icmp_add: gettimeofday");
event_del(&cie->ev);
event_set(&cie->ev, cie->s, EV_TIMEOUT|flags, fn, cie);
event_add(&cie->ev, &tv);
}
void
check_icmp(struct relayd *env, struct timeval *tv)
{
if (env->sc_has_icmp) {
check_icmp_add(&env->sc_icmp_recv, EV_READ, tv, recv_icmp);
check_icmp_add(&env->sc_icmp_send, EV_WRITE, tv, send_icmp);
}
if (env->sc_has_icmp6) {
check_icmp_add(&env->sc_icmp6_recv, EV_READ, tv, recv_icmp);
check_icmp_add(&env->sc_icmp6_send, EV_WRITE, tv, send_icmp);
}
}
int
icmp_checks_done(struct ctl_icmp_event *cie)
{
struct table *table;
struct host *host;
TAILQ_FOREACH(table, cie->env->sc_tables, entry) {
if (table->conf.flags & F_DISABLE ||
table->conf.check != CHECK_ICMP)
continue;
TAILQ_FOREACH(host, &table->hosts, entry) {
if (((struct sockaddr *)&host->conf.ss)->sa_family !=
cie->af)
continue;
if (!(host->flags & F_CHECK_DONE))
return (0);
}
}
return (1);
}
void
icmp_checks_timeout(struct ctl_icmp_event *cie, enum host_error he)
{
struct table *table;
struct host *host;
TAILQ_FOREACH(table, cie->env->sc_tables, entry) {
if (table->conf.flags & F_DISABLE ||
table->conf.check != CHECK_ICMP)
continue;
TAILQ_FOREACH(host, &table->hosts, entry) {
if (((struct sockaddr *)&host->conf.ss)->sa_family !=
cie->af)
continue;
if (!(host->flags & F_CHECK_DONE)) {
host->up = HOST_DOWN;
hce_notify_done(host, he);
}
}
}
}
void
send_icmp(int s, short event, void *arg)
{
struct ctl_icmp_event *cie = (struct ctl_icmp_event *)arg;
struct table *table;
struct host *host;
struct sockaddr *to;
struct icmp *icp;
struct icmp6_hdr *icp6;
ssize_t r;
u_char packet[ICMP_BUF_SIZE];
socklen_t slen;
int i = 0;
if (event == EV_TIMEOUT) {
icmp_checks_timeout(cie, HCE_ICMP_WRITE_TIMEOUT);
return;
}
bzero(&packet, sizeof(packet));
icp = (struct icmp *)packet;
icp6 = (struct icmp6_hdr *)packet;
if (cie->af == AF_INET) {
icp->icmp_type = ICMP_ECHO;
icp->icmp_code = 0;
icp->icmp_id = htons(cie->env->sc_id);
icp->icmp_cksum = 0;
slen = sizeof(struct sockaddr_in);
} else {
icp6->icmp6_type = ICMP6_ECHO_REQUEST;
icp6->icmp6_code = 0;
icp6->icmp6_cksum = 0;
icp6->icmp6_id = htons(cie->env->sc_id);
slen = sizeof(struct sockaddr_in6);
}
TAILQ_FOREACH(table, cie->env->sc_tables, entry) {
if (table->conf.check != CHECK_ICMP ||
table->conf.flags & F_DISABLE)
continue;
TAILQ_FOREACH(host, &table->hosts, entry) {
if (host->flags & (F_DISABLE | F_CHECK_SENT) ||
host->conf.parentid)
continue;
if (((struct sockaddr *)&host->conf.ss)->sa_family !=
cie->af)
continue;
i++;
to = (struct sockaddr *)&host->conf.ss;
if (cie->af == AF_INET) {
icp->icmp_seq = htons(i);
icp->icmp_cksum = 0;
memcpy(icp->icmp_data, &host->conf.id,
sizeof(host->conf.id));
icp->icmp_cksum = in_cksum((u_short *)icp,
sizeof(packet));
} else {
icp6->icmp6_seq = htons(i);
icp6->icmp6_cksum = 0;
memcpy(packet + sizeof(*icp6), &host->conf.id,
sizeof(host->conf.id));
icp6->icmp6_cksum = in_cksum((u_short *)icp6,
sizeof(packet));
}
r = sendto(s, packet, sizeof(packet), 0, to, slen);
if (r == -1) {
if (errno == EAGAIN || errno == EINTR)
goto retry;
host->flags |= F_CHECK_SENT|F_CHECK_DONE;
host->up = HOST_DOWN;
} else if (r != sizeof(packet))
goto retry;
host->flags |= F_CHECK_SENT;
}
}
return;
retry:
event_again(&cie->ev, s, EV_TIMEOUT|EV_WRITE, send_icmp,
&cie->tv_start, &cie->env->sc_timeout, cie);
}
void
recv_icmp(int s, short event, void *arg)
{
struct ctl_icmp_event *cie = (struct ctl_icmp_event *)arg;
u_char packet[ICMP_BUF_SIZE];
socklen_t slen;
struct sockaddr_storage ss;
struct icmp *icp;
struct icmp6_hdr *icp6;
u_int16_t icpid;
struct host *host;
ssize_t r;
objid_t id;
if (event == EV_TIMEOUT) {
icmp_checks_timeout(cie, HCE_ICMP_READ_TIMEOUT);
return;
}
bzero(&packet, sizeof(packet));
bzero(&ss, sizeof(ss));
r = recvfrom(s, packet, sizeof(packet), 0,
(struct sockaddr *)&ss, &slen);
if (r == -1 || r != ICMP_BUF_SIZE) {
if (r == -1 && errno != EAGAIN && errno != EINTR)
log_debug("recv_icmp: receive error");
goto retry;
}
if (cie->af == AF_INET) {
icp = (struct icmp *)(packet + sizeof(struct ip));
icpid = ntohs(icp->icmp_id);
memcpy(&id, icp->icmp_data, sizeof(id));
} else {
icp6 = (struct icmp6_hdr *)packet;
icpid = ntohs(icp6->icmp6_id);
memcpy(&id, packet + sizeof(*icp6), sizeof(id));
}
if (icpid != cie->env->sc_id)
goto retry;
host = host_find(cie->env, id);
if (host == NULL) {
log_warn("recv_icmp: ping for unknown host received");
goto retry;
}
if (bcmp(&ss, &host->conf.ss, slen)) {
log_warnx("recv_icmp: forged icmp packet?");
goto retry;
}
host->up = HOST_UP;
host->flags |= F_CHECK_DONE;
hce_notify_done(host, HCE_ICMP_OK);
if (icmp_checks_done(cie))
return;
retry:
event_again(&cie->ev, s, EV_TIMEOUT|EV_READ, recv_icmp,
&cie->tv_start, &cie->env->sc_timeout, cie);
}
/* in_cksum from ping.c --
* Checksum routine for Internet Protocol family headers (C Version)
*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Muuss.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
int
in_cksum(u_short *addr, int len)
{
int nleft = len;
u_short *w = addr;
int sum = 0;
u_short answer = 0;
/*
* Our algorithm is simple, using a 32 bit accumulator (sum), we add
* sequential 16 bit words to it, and at the end, fold back all the
* carry bits from the top 16 bits into the lower 16 bits.
*/
while (nleft > 1) {
sum += *w++;
nleft -= 2;
}
/* mop up an odd byte, if necessary */
if (nleft == 1) {
*(u_char *)(&answer) = *(u_char *)w ;
sum += answer;
}
/* add back carry outs from top 16 bits to low 16 bits */
sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
sum += (sum >> 16); /* add carry */
answer = ~sum; /* truncate to 16 bits */
return (answer);
}