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/* connect.c - Open connection to server.
*
* Copyright (C) 2010, Pawel Krawczyk <pawel.krawczyk@hush.com> and
* Jeroen Nijhof <jeroen@jeroennijhof.nl>
*
* 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.
*
* See `CHANGES' file for revision history.
*/
#include <signal.h>
#include <arpa/inet.h>
#include <time.h>
#include <fcntl.h>
#include <errno.h>
#ifdef _AIX
#include <sys/socket.h>
#endif
#include "libtac.h"
/* Pointer to TACACS+ connection timeout */
int tac_timeout = 5;
/* Returns file descriptor of open connection
to the first available server from list passed
in server table.
* return value:
* >= 0 : valid fd
* < 0 : error status code, see LIBTAC_STATUS_...
* iface is used to bind to an interface or VRF if non-null
*/
int tac_connect(struct addrinfo **server, char **key, int servers, char *iface) {
int tries;
int fd=-1;
if(servers == 0 || server == NULL) {
TACSYSLOG((LOG_ERR, "%s: no TACACS+ servers defined", __func__))
} else {
for ( tries = 0; tries < servers; tries++ ) {
if((fd=tac_connect_single(server[tries], key[tries], NULL, iface)) >= 0 ) {
/* tac_secret was set in tac_connect_single on success */
break;
}
}
}
/* all attempts failed if fd is still < 0 */
TACDEBUG((LOG_DEBUG, "%s: exit status=%d",__func__, fd))
return fd;
} /* tac_connect */
/* return value:
* >= 0 : valid fd
* < 0 : error status code, see LIBTAC_STATUS_...
* If iface is non-null, try to setsockopt SO_BINDTODEVICE to that iface
* to support specific routing, including VRF.
* if srcaddr is non-null, try to bind() to that address to support
* specifying source IP addres
*/
int tac_connect_single(struct addrinfo *server, const char *key,
struct addrinfo *srcaddr, char *iface) {
int retval = LIBTAC_STATUS_CONN_ERR; /* default retval */
int fd = -1;
int flags, rc;
fd_set readfds, writefds;
struct timeval tv;
socklen_t len;
struct sockaddr_storage addr;
char *ip;
if(server == NULL) {
TACSYSLOG((LOG_ERR, "%s: no TACACS+ server defined", __func__))
return LIBTAC_STATUS_CONN_ERR;
}
/* format server address into a string for use in messages */
ip = tac_ntop(server->ai_addr);
if((fd=socket(server->ai_family, server->ai_socktype, server->ai_protocol)) < 0) {
TACSYSLOG((LOG_ERR,"%s: socket creation error: %s", __func__,
strerror(errno)))
retval = LIBTAC_STATUS_CONN_ERR;
goto error;
}
if (iface) {
/* do not fail if the bind fails, connection may still succeed */
if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, iface,
strlen(iface)+1) < 0)
TACSYSLOG((LOG_WARNING, "%s: Binding socket to device %s failed: %m",
__func__, iface))
}
/* get flags for restoration later */
flags = fcntl(fd, F_GETFL, 0);
/* put socket in non blocking mode for timeout support */
if( fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1 ) {
TACSYSLOG((LOG_ERR, "%s: cannot set socket non blocking",\
__func__))
retval = LIBTAC_STATUS_CONN_ERR;
goto error;
}
/* bind if source address got explicity defined */
if (srcaddr) {
if (bind(fd, srcaddr->ai_addr, srcaddr->ai_addrlen) < 0) {
TACSYSLOG((LOG_ERR, "%s: Failed to bind source address: %s",
__func__, strerror(errno)))
retval = LIBTAC_STATUS_CONN_ERR;
goto error;
}
}
rc = connect(fd, server->ai_addr, server->ai_addrlen);
/* FIX this..for some reason errno = 0 on AIX... */
if((rc == -1) && (errno != EINPROGRESS) && (errno != 0)) {
TACSYSLOG((LOG_ERR,\
"%s: connection to %s failed: %m", __func__, ip))
retval = LIBTAC_STATUS_CONN_ERR;
goto error;
}
/* set fds for select */
FD_ZERO(&readfds);
FD_ZERO(&writefds);
FD_SET(fd, &readfds);
FD_SET(fd, &writefds);
/* set timeout seconds */
tv.tv_sec = tac_timeout;
tv.tv_usec = 0;
/* check if socket is ready for read and write */
rc = select(fd+1, &readfds, &writefds, NULL, &tv);
/* timeout */
if ( rc == 0 ) {
retval = LIBTAC_STATUS_CONN_TIMEOUT;
goto error;
}
/* some other error or interrupt before timeout */
if ( rc < 0 ) {
TACSYSLOG((LOG_ERR,\
"%s: connection failed with %s: %m", __func__, ip))
retval = LIBTAC_STATUS_CONN_ERR;
goto error;
}
/* check with getpeername if we have a valid connection */
len = sizeof addr;
if(getpeername(fd, (struct sockaddr*)&addr, &len) == -1) {
TACSYSLOG((LOG_ERR,\
"%s: getpeername failed with %s: %m", __func__, ip))
retval = LIBTAC_STATUS_CONN_ERR;
goto error;
}
/* restore flags on socket */
if (flags & O_NONBLOCK) {
flags &= ~O_NONBLOCK;
}
if(fcntl(fd, F_SETFL, flags) == -1) {
TACSYSLOG((LOG_ERR, "%s: cannot restore socket flags: %m",\
__func__))
retval = LIBTAC_STATUS_CONN_ERR;
goto error;
}
/* connected ok */
TACDEBUG((LOG_DEBUG, "%s: connected to %s", __func__, ip))
retval = fd;
/* set current tac_secret */
tac_encryption = 0;
if (key != NULL && *key) {
tac_encryption = 1;
tac_secret = key;
}
error:
if (retval < 0 && fd >= 0) /* we had an error, don't leak fd */
close(fd);
TACDEBUG((LOG_DEBUG, "%s: exit status=%d (fd=%d)",\
__func__, retval < 0 ? retval:0, fd))
return retval;
} /* tac_connect_single */
/* return value:
* ptr to char* with format IP address
* warning: returns a static buffer
* (which some ppl don't like, but it's robust and at last no more memory leaks)
*/
char *tac_ntop(const struct sockaddr *sa) {
static char server_address[INET6_ADDRSTRLEN+16];
switch(sa->sa_family) {
case AF_INET:
inet_ntop(AF_INET, &(((struct sockaddr_in *)sa)->sin_addr),
server_address, INET_ADDRSTRLEN);
snprintf(server_address + strlen(server_address), 14, ":%hu",
htons(((struct sockaddr_in *)sa)->sin_port));
break;
case AF_INET6:
inet_ntop(AF_INET6, &(((struct sockaddr_in6 *)sa)->sin6_addr),
server_address, INET6_ADDRSTRLEN);
snprintf(server_address + strlen(server_address), 14, ":%hu",
htons(((struct sockaddr_in6 *)sa)->sin6_port));
break;
default:
strcpy(server_address, "Unknown AF");
}
return server_address;
} /* tac_ntop */
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