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/*
* Copyright © 2005-2008 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions of the
* GNU General Public License v.2. This program is distributed in the hope
* that it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
* including the implied warranties 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; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. Any Red Hat
* trademarks that are incorporated in the source code or documentation are not
* subject to the GNU General Public License and may only be used or replicated
* with the express permission of Red Hat, Inc.
*
* Red Hat Author(s): Nathan Straz <nstraz@redhat.com>
* Dean Jansa <djansa@redhat.com>
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "btime_int.h"
static int same_addr(struct sockaddr_storage *a, struct sockaddr_storage *b);
static void gen_cookie(char *s);
/*
* btime --
*
* Return the boot time of a remote host if that host is running the
* btimed deamon.
*
* Returns:
* btime, or 0 on failure.
*/
unsigned int
btime(const char *host)
{
int sd;
char cookie[BTIME_MSGLEN];
char response[BTIME_MSGLEN];
struct addrinfo *serv_ail, *serv_aip;
struct addrinfo *my_ail, *my_aip;
struct sockaddr_storage resp_addr;
struct addrinfo hints;
socklen_t resp_addr_len;
unsigned int btime = 0;
ssize_t nbytes;
int retry;
fd_set sdset;
struct timeval timeout;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
if (getaddrinfo(host, "5016", &hints, &serv_ail) != 0) {
fprintf(stderr, "Could not get address info for %s: %s\n",
host, strerror(errno));
return 0;
}
for (serv_aip = serv_ail; serv_aip != NULL; serv_aip = serv_aip->ai_next) {
if ((sd = socket(serv_aip->ai_family, serv_aip->ai_socktype,
serv_aip->ai_protocol)) < 0) {
continue;
}
break;
}
if (serv_aip == NULL) {
fprintf(stderr, "Could not create socket: %s\n", strerror(errno));
freeaddrinfo(serv_ail);
return 0;
}
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = AI_PASSIVE; /* Fill in my IP for me */
if (getaddrinfo(NULL, "0", &hints, &my_ail) != 0) {
fprintf(stderr, "Could not get address info for myself!: %s\n", strerror(errno));
return 0;
}
for (my_aip = my_ail; my_aip != NULL; my_aip = my_aip->ai_next) {
if (bind(sd, my_aip->ai_addr, my_aip->ai_addrlen) < 0) {
continue;
}
break;
}
if (my_aip == NULL) {
fprintf(stderr, "Could not bind to local address: %s\n",
strerror(errno));
freeaddrinfo(my_ail);
return 0;
}
memset(cookie, 0, BTIME_MSGLEN);
gen_cookie(cookie);
for (retry = 0; retry < MAX_RETRY; retry++) {
if ((nbytes = sendto(sd, &cookie, BTIME_MSGLEN, MSG_DONTWAIT,
serv_aip->ai_addr, serv_aip->ai_addrlen)) < 0) {
if (errno == EAGAIN) {
usleep(retry * 100);
} else {
/* Non EAGAIN error... */
break;
}
} else {
break;
}
}
FD_ZERO(&sdset);
FD_SET(sd, &sdset);
do {
retry = 0;
timeout.tv_sec = 0;
timeout.tv_usec = 500000;
if (select(sd + 1, &sdset, NULL, NULL, &timeout) != 1) {
/* Either an error or a timeout, we don't need to retry */
break;
}
memset(&resp_addr, 0, sizeof resp_addr);
memset(response, 0, BTIME_MSGLEN);
resp_addr_len = sizeof resp_addr;
nbytes = recvfrom(sd, &response, BTIME_MSGLEN, MSG_DONTWAIT,
(struct sockaddr *)&resp_addr, &resp_addr_len);
if (nbytes == 0) {
/* Nothing received */
continue;
} else if (response[0] == 'B' && response[1] == 'T') {
/* Check for new style cookie */
if (memcmp(cookie, response, COOKIE_LEN) == 0) {
btime = strtoul(response+COOKIE_LEN, NULL, 10);
break;
} else {
/* ignore the invalid btime cookie */
retry = 1;
continue;
}
} else if (!same_addr((struct sockaddr_storage *)serv_aip->ai_addr, &resp_addr)) {
/* If no cookie, check peer */
char rstr[NI_MAXHOST];
char sstr[NI_MAXHOST];
inet_ntop(resp_addr.ss_family, &resp_addr, rstr, NI_MAXHOST);
inet_ntop(serv_aip->ai_family, serv_aip->ai_addr, sstr, NI_MAXHOST);
fprintf(stderr, "Got response from %s instead of %s\n",
rstr, sstr);
retry = 1;
continue;
} else {
/* If peer matches, accept the bare btime */
btime = strtoul(response, (char **)NULL, 10);
break;
}
} while (retry);
close(sd);
freeaddrinfo(serv_ail);
freeaddrinfo(my_ail);
return btime;
}
/* same_addr
*
* Compare two struct sockaddr_storage
*
* Returns:
* 1 if the addresses match
* 0 if the addresses are different
*/
static int
same_addr(struct sockaddr_storage *a, struct sockaddr_storage *b)
{
return 1;
if (a->ss_family != b->ss_family) {
return 0;
} else if ((a->ss_family == AF_INET)
&& (((struct sockaddr_in *)a)->sin_addr.s_addr
!= ((struct sockaddr_in *)b)->sin_addr.s_addr)) {
return 0;
} else if ((a->ss_family == AF_INET6)
&& (((struct sockaddr_in6 *)a)->sin6_addr.s6_addr
!= ((struct sockaddr_in6 *)b)->sin6_addr.s6_addr)) {
return 0;
} else {
return 1;
}
}
/* gen_cookie
*
* Generate a random string that btimed will send back to us.
*/
static void gen_cookie(char *s)
{
char *a = s;
int i;
*a++ = 'B';
*a++ = 'T';
for (i = 0; i < COOKIE_RANDOM_PARTS; i++) {
*(int32_t *)a = (int32_t)random();
a += sizeof(int32_t);
}
*a = '\n';
}
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