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redir.c
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redir.c
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/* $Id$
*
* redir - a utility for redirecting tcp connections
*
* Author: Nigel Metheringham
*
* Based on, but much modified from, code originally written by
* [email protected] - original header is below.
*
* redir is released under the GNU General Public license,
* version 2, or at your discretion, any later version.
*
*/
/*
* redir is currently maintained by Sam Creasey ([email protected]).
* Please send patches, etc. there.
*
*/
/* 980601: dl9sau
* added some nice new features:
*
* --bind_addr=my.other.ip.address
* forces to use my.other.ip.address for the outgoing connection
*
* you can also specify, that redir listens not on all IP addresses of
* your system but only for the given one, i.e.:
* if my host has the addresses
* irc.thishost.my.domain and mail.thishost.my.domain
* but you want that your users do connect for the irc redir service
* only on irc.thishost.my.domain, then do it this way:
* redir irc.fu-berlin.de irc.thishost.mydomain:6667 6667
* my need was that:
* addr1.first.domain 6667 redirects to irc.first.net port 6667
* and addr2.second.domain 6667 redirects to irc.second.net port 6667
* while addr1 and addr2 are the same maschine and the ports can be equal.
*
* enjoy it!
* - thomas <[email protected]>, <[email protected]>
*
* btw: i tried without success implementing code for the following scenario:
* redir --force_addr irc.fu-berlin.de 6667 6667
* if "--force_addr" is given and a user connects to my system, that address
* of my system will be used on the outgoing connection that the user
* connected to.
* i was not successful to determine, to which of my addresses the user
* has connected.
*/
/* 990320 added support for ftp connection done by the client, now this code
* should work for all ftp clients.
*
* - harald <[email protected]>
*/
/* 991221 added options to simulate a slow connection and to limit
* bandwidth.
*
* - Emmanuel Chantréau <[email protected]>
*/
#define VERSION "2.2.1"
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <getopt.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#ifdef USE_TCP_WRAPPERS
#include <tcpd.h>
#endif
#define debug(x) if (dodebug) fprintf(stderr, x)
#define debug1(x,y) if (dodebug) fprintf(stderr, x, y)
/* let's set up some globals... */
int dodebug = 0;
int dosyslog = 0;
unsigned char reuse_addr = 1;
unsigned char linger_opt = 0;
char * bind_addr = NULL;
struct sockaddr_in addr_out;
int timeout = 0;
#ifndef NO_FTP
int ftp = 0;
#endif
int transproxy = 0;
#ifndef NO_SHAPER
int max_bandwidth = 0;
int random_wait = 0;
int wait_in_out=3; /* bit 0: wait for "in", bit 1: wait for "out" */
int wait_in=1;
int wait_out=1;
#endif
unsigned int bufsize=4096;
char *connect_str = NULL; /* CONNECT string passed to proxy */
char * ident = NULL;
#ifndef NO_FTP
/* what ftp to redirect */
#define FTP_PORT 1
#define FTP_PASV 2
#endif
#ifdef USE_TCP_WRAPPERS
struct request_info request;
int allow_severity = LOG_INFO;
int deny_severity = LOG_WARNING;
#endif /* USE_TCP_WRAPPERS */
#ifdef NEED_STRRCHR
#define strrchr rindex
#endif /* NEED_STRRCHR */
#define REDIR_IN 1
#define REDIR_OUT 0
/* prototype anything needing it */
void do_accept(int servsock, struct sockaddr_in *target);
int bindsock(char *addr, int port, int fail);
#ifndef NO_SHAPER
/* Used in this program to write something in a socket, it has the same
parameters and return value as "write", but with the flag "in": true if
it's the "in" socket and false if it's the "out" socket */
static inline ssize_t redir_write (int fd, const void *buf, size_t size, int in)
{
ssize_t result;
int wait;
wait=in ? wait_in : wait_out;
if( random_wait > 0 && wait) {
fd_set empty;
struct timeval waitbw; /* for bandwidth */
int rand_time;
FD_ZERO(&empty);
rand_time=rand()%(random_wait*2);
debug1("random wait: %u\n", rand_time);
waitbw.tv_sec=rand_time/1000;
waitbw.tv_usec=rand_time%1000;
select (1, &empty, NULL, NULL, &waitbw);
}
result=write(fd, buf, size);
if( max_bandwidth > 0 && wait) {
fd_set empty;
unsigned long bits;
struct timeval waitbw; /* for bandwidth */
FD_ZERO(&empty);
/* wait to be sure tu be below the allowed bandwidth */
bits=size*8;
debug1("bandwidth wait: %lu\n", 1000*bits/max_bandwidth);
waitbw.tv_sec=bits/max_bandwidth;
waitbw.tv_usec=(1000*(bits%max_bandwidth))/max_bandwidth;
select (1, &empty, NULL, NULL, &waitbw);
}
return result;
}
#else
/* macro if traffic shaper is disabled */
#define redir_write(fd, buf, size, in) write(fd, buf,size)
#endif
#ifdef NEED_STRDUP
char *
strdup(char * str)
{
char * result;
if (result = (char *) malloc(strlen(str) + 1))
strcpy(result, str);
return result;
}
#endif /* NEED_STRDUP */
void
redir_usage(char *name)
{
fprintf(stderr,"usage:\n");
fprintf(stderr,
"\t%s --lport=<n> --cport=<n> [options]\n",
name);
fprintf(stderr, "\t%s --inetd --cport=<n>\n", name);
fprintf(stderr, "\n\tOptions are:-\n");
fprintf(stderr, "\t\t--lport=<n>\t\tport to listen on\n");
fprintf(stderr, "\t\t--laddr=IP\t\taddress of interface to listen on\n");
fprintf(stderr, "\t\t--cport=<n>\t\tport to connect to\n");
fprintf(stderr, "\t\t--caddr=<host>\t\tremote host to connect to\n");
fprintf(stderr, "\t\t--inetd\t\trun from inetd\n");
fprintf(stderr, "\t\t--debug\t\toutput debugging info\n");
fprintf(stderr, "\t\t--timeout=<n>\tset timeout to n seconds\n");
fprintf(stderr, "\t\t--syslog\tlog messages to syslog\n");
fprintf(stderr, "\t\t--name=<str>\ttag syslog messages with 'str'\n");
fprintf(stderr, "\t\t--connect=<str>\tCONNECT string passed to proxy server\n");
#ifdef USE_TCP_WRAPPERS
fprintf(stderr, "\t\t \tAlso used as service name for TCP wrappers\n");
#endif /* USE_TCP_WRAPPERS */
fprintf(stderr, "\t\t--bind_addr=IP\tbind() outgoing IP to given addr\n");
#ifndef NO_FTP
fprintf(stderr, "\t\t--ftp=<type>\t\tredirect ftp connections\n");
fprintf(stderr, "\t\t\twhere type is either port, pasv, both\n");
#endif
fprintf(stderr, "\t\t--transproxy\trun in linux's transparent proxy mode\n");
#ifndef NO_SHAPER
/* options for bandwidth */
fprintf(stderr, "\t\t--bufsize=<octets>\tsize of the buffer\n");
fprintf(stderr, "\t\t--maxbandwidth=<bit-per-sec>\tlimit the bandwidth\n");
fprintf(stderr, "\t\t--random_wait=<millisec>\twait before each packet\n");
fprintf(stderr, "\t\t--wait_in_out=<flag>\t1 wait for in, 2 out, 3 in&out\n");
/* end options for bandwidth */
#endif
fprintf(stderr, "\n\tVersion %s.\n", VERSION);
exit(2);
}
void
parse_args(int argc,
char * argv[],
char ** target_addr,
int * target_port,
char ** local_addr,
int * local_port,
int * timeout,
int * dodebug,
int * inetd,
int * dosyslog,
char ** bind_addr,
#ifndef NO_FTP
int * ftp,
#endif
int *transproxy,
#ifndef NO_SHAPER
unsigned int * bufsize,
int * max_bandwidth,
int * random_wait,
int * wait_in_out,
#endif
char **connect_str)
{
static struct option long_options[] = {
{"lport", required_argument, 0, 'l'},
{"laddr", required_argument, 0, 'a'},
{"cport", required_argument, 0, 'r'},
{"caddr", required_argument, 0, 'c'},
{"bind_addr", required_argument, 0, 'b'},
{"debug", no_argument, 0, 'd'},
{"timeout", required_argument, 0, 't'},
{"inetd", no_argument, 0, 'i'},
{"ident", required_argument, 0, 'n'},
{"name", required_argument, 0, 'n'},
{"syslog", no_argument, 0, 's'},
{"ftp", required_argument, 0, 'f'},
{"transproxy", no_argument, 0, 'p'},
{"connect", required_argument, 0, 'x'},
{"bufsize", required_argument, 0, 'z'},
{"max_bandwidth", required_argument, 0, 'm'},
{"random_wait", required_argument, 0, 'w'},
{"wait_in_out", required_argument, 0, 'o'},
{0,0,0,0} /* End marker */
};
int option_index = 0;
extern int optind;
int opt;
struct servent *portdesc;
char *lport = NULL;
char *tport = NULL;
#ifndef NO_FTP
char *ftp_type = NULL;
#endif
*local_addr = NULL;
*target_addr = NULL;
*target_port = 0;
*local_port = 0;
while ((opt = getopt_long(argc, argv, "disfpn:t:b:a:l:r:c:x:z:m:w:o:",
long_options, &option_index)) != -1) {
switch (opt) {
case 'x':
*connect_str = optarg;
break;
case 'a':
*local_addr = optarg;
break;
case 'l':
lport = optarg;
break;
case 'r':
tport = optarg;
break;
case 'c':
*target_addr = optarg;
break;
case 'b':
*bind_addr = optarg;
break;
case 'd':
(*dodebug)++;
break;
case 't':
*timeout = atol(optarg);
break;
case 'i':
(*inetd)++;
break;
case 'n':
/* This is the ident which is added to syslog messages */
ident = optarg;
break;
case 's':
(*dosyslog)++;
break;
#ifndef NO_FTP
case 'f':
ftp_type = optarg;
if(!ftp_type) {
redir_usage(argv[0]);
exit(1);
}
break;
#endif
case 'p':
(*transproxy)++;
break;
#ifndef NO_SHAPER
case 'z':
*bufsize = (unsigned int)atol(optarg);
break;
case 'm':
*max_bandwidth = atol(optarg);
break;
case 'w':
*random_wait = atol(optarg);
break;
case 'o':
*wait_in_out = atol(optarg);
wait_in=*wait_in_out & 1;
wait_out=*wait_in_out & 2;
break;
#endif
default:
redir_usage(argv[0]);
exit(1);
break;
}
}
if(tport == NULL)
{
redir_usage(argv[0]);
exit(1);
}
if ((portdesc = getservbyname(tport, "tcp")) != NULL) {
*target_port = ntohs(portdesc->s_port);
} else {
*target_port = atol(tport);
}
/* only check local port if not running from inetd */
if(!(*inetd)) {
if(lport == NULL)
{
redir_usage(argv[0]);
exit(1);
}
if ((portdesc = getservbyname(lport, "tcp")) != NULL)
*local_port = ntohs(portdesc->s_port);
else
*local_port = atol(lport);
} /* if *inetd */
if (!ident) {
if ((ident = (char *) strrchr(argv[0], '/'))) {
ident++;
} else {
ident = argv[0];
}
}
#ifndef NO_FTP
/* some kind of ftp being forwarded? */
if(ftp_type) {
if(!strncasecmp(ftp_type, "port", 4))
*ftp = FTP_PORT;
else if(!strncasecmp(ftp_type, "pasv", 4))
*ftp = FTP_PASV;
else if(!strncasecmp(ftp_type, "both", 4))
*ftp = FTP_PORT | FTP_PASV;
else {
redir_usage(argv[0]);
exit(1);
}
}
#endif
openlog(ident, LOG_PID, LOG_DAEMON);
return;
}
#ifndef NO_FTP
/* with the --ftp option, this one changes passive mode replies from
the ftp server to point to a new redirector which we spawn,
now it also change the PORT commando when the client accept the
dataconnection */
void ftp_clean(int send, char *buf, unsigned long *bytes, int ftpsrv)
{
char *port_start;
int rporthi, lporthi;
int lportlo, rportlo;
int lport, rport;
int remip[4];
int localsock;
int socksize = sizeof(struct sockaddr_in);
struct sockaddr_in newsession;
struct sockaddr_in sockname;
if (ftpsrv == 0)
{
/* is this a port commando ? */
if(strncmp(buf, "PORT", 4)) {
redir_write(send, buf, (*bytes), REDIR_OUT);
return;
}
/* parse the old address out of the buffer */
port_start = strchr(buf, ' ');
sscanf(port_start, " %d,%d,%d,%d,%d,%d", &remip[0], &remip[1],
&remip[2], &remip[3], &rporthi, &rportlo);
} else {
/* is this a passive mode return ? */
if(strncmp(buf, "227", 3)) {
redir_write(send, buf, (*bytes), REDIR_OUT);
return;
}
/* parse the old address out of the buffer */
port_start = strchr(buf, '(');
sscanf(port_start, "(%d,%d,%d,%d,%d,%d", &remip[0], &remip[1],
&remip[2], &remip[3], &rporthi, &rportlo);
}
/* get the outside interface so we can listen */
if(getsockname(send, (struct sockaddr *)&sockname, &socksize) != 0) {
perror("getsockname");
exit(1);
}
rport = (rporthi << 8) | rportlo;
/* we need to listen on a port for the incoming connection.
we will use the port 0, so let the system pick one. */
localsock = bindsock(inet_ntoa(sockname.sin_addr), 0, 1);
/* get the real info */
if(getsockname(localsock, (struct sockaddr *)&sockname, &socksize) < 0) {
perror("getsockname");
if (dosyslog)
syslog(LOG_ERR, "getsockname failed: %m");
exit(1);
}
lport = ntohs(sockname.sin_port);
lporthi=(lport >> 8 ) & 0xff;
lportlo=lport & 0xff;
/* check to see if we bound */
if(localsock == -1) {
fprintf(stderr, "ftp: unable to bind new listening address\n");
exit(1);
}
if (ftpsrv == 0) {
/* send the new port and ipaddress to the server */
(*bytes) = sprintf(buf, "PORT %d,%d,%d,%d,%d,%d\n",
sockname.sin_addr.s_addr & 0xff,
(sockname.sin_addr.s_addr >> 8) & 0xff,
(sockname.sin_addr.s_addr >> 16) & 0xff,
sockname.sin_addr.s_addr >> 24, lporthi, lportlo);
} else {
/* send the new port and ipaddress to the client */
(*bytes) = sprintf(buf, "227 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\n",
sockname.sin_addr.s_addr & 0xff,
(sockname.sin_addr.s_addr >> 8) & 0xff,
(sockname.sin_addr.s_addr >> 16) & 0xff,
sockname.sin_addr.s_addr >> 24, lporthi, lportlo);
}
newsession.sin_port = htons(rport);
newsession.sin_family = AF_INET;
newsession.sin_addr.s_addr = remip[0] | (remip[1] << 8)
| (remip[2] << 16) | (remip[3] << 24);
debug1("ftpdata server ip: %s\n", inet_ntoa(newsession.sin_addr));
debug1("ftpdata server port: %d\n", rport);
debug1("listening for ftpdata on port %d\n", lport);
debug1("listening for ftpdata on addr %s\n", inet_ntoa(sockname.sin_addr));
/* now that we're bound and listening, we can safely send the new
string without fear of them getting a connection refused. */
redir_write(send, buf, (*bytes), REDIR_OUT);
/* make a new process to handle the dataconnection correctly,
for the PASV mode this isn't a problem because after sending the
PASV command, the data connection, get active. For the PORT command
the server must send a success, if starting here with the copyloop
the success command never arrive the client.*/
switch(fork())
{
case -1: /* Error */
syslog(LOG_ERR, "Couldn't fork: %m");
_exit(1);
case 0: /* Child */
{
/* turn off ftp checking while the data connection is active */
ftp = 0;
do_accept(localsock, &newsession);
close(localsock);
_exit(0);
}
default: /* Parent */
{ close(localsock); }
}
return;
}
#endif
void
copyloop(int insock,
int outsock,
int timeout_secs)
{
fd_set iofds;
fd_set c_iofds;
int max_fd; /* Maximum numbered fd used */
struct timeval timeout;
unsigned long bytes;
unsigned long bytes_in = 0;
unsigned long bytes_out = 0;
unsigned int start_time, end_time;
char buf[bufsize];
/* Record start time */
start_time = (unsigned int) time(NULL);
/* Set up timeout */
timeout.tv_sec = timeout_secs;
timeout.tv_usec = 0;
/* file descriptor bits */
FD_ZERO(&iofds);
FD_SET(insock, &iofds);
FD_SET(outsock, &iofds);
if (insock > outsock) {
max_fd = insock;
} else {
max_fd = outsock;
}
debug1("Entering copyloop() - timeout is %d\n", timeout_secs);
while(1) {
(void) memcpy(&c_iofds, &iofds, sizeof(iofds));
if (select(max_fd + 1,
&c_iofds,
(fd_set *)0,
(fd_set *)0,
(timeout_secs ? &timeout : NULL)) <= 0) {
/* syslog(LLEV,"connection timeout: %d sec",timeout.tv_sec);*/
break;
}
if(FD_ISSET(insock, &c_iofds)) {
if((bytes = read(insock, buf, sizeof(buf))) <= 0)
break;
#ifndef NO_FTP
if (ftp & FTP_PORT)
/* if we're correcting FTP, lookup for a PORT commando
in the buffer, if yes change this and establish
a new redirector for the data */
ftp_clean(outsock, buf, &bytes,0);
else
#endif
if(redir_write(outsock, buf, bytes, REDIR_OUT) != bytes)
break;
bytes_out += bytes;
}
if(FD_ISSET(outsock, &c_iofds)) {
if((bytes = read(outsock, buf, sizeof(buf))) <= 0)
break;
/* if we're correcting for PASV on ftp redirections, then
fix buf and bytes to have the new address, among other
things */
#ifndef NO_FTP
if(ftp & FTP_PASV)
ftp_clean(insock, buf, &bytes,1);
else
#endif
if(redir_write(insock, buf, bytes, REDIR_IN) != bytes)
break;
bytes_in += bytes;
}
}
debug("Leaving main copyloop\n");
/*
setsockopt(insock, SOL_SOCKET, SO_REUSEADDR, &reuse_addr, sizeof(reuse_addr));
setsockopt(insock, SOL_SOCKET, SO_LINGER, &linger_opt, sizeof(SO_LINGER));
setsockopt(outsock, SOL_SOCKET, SO_REUSEADDR, &reuse_addr, sizeof(reuse_addr));
setsockopt(outsock, SOL_SOCKET, SO_LINGER, &linger_opt, sizeof(SO_LINGER));
*/
shutdown(insock,0);
shutdown(outsock,0);
close(insock);
close(outsock);
debug("copyloop - sockets shutdown and closed\n");
end_time = (unsigned int) time(NULL);
debug1("copyloop - connect time: %8d seconds\n", end_time - start_time);
debug1("copyloop - transfer in: %8ld bytes\n", bytes_in);
debug1("copyloop - transfer out: %8ld bytes\n", bytes_out);
if (dosyslog) {
syslog(LOG_NOTICE, "disconnect %d secs, %ld in %ld out",
(end_time - start_time), bytes_in, bytes_out);
}
return;
}
void doproxyconnect(int socket)
{
char buf[128];
int x;
/* write CONNECT string to proxy */
sprintf((char *) &buf, "CONNECT %s HTTP/1.0\n\n", connect_str);
x = write(socket, (char *) &buf, strlen(buf));
if (x < 1) {
perror("doproxyconnect: failed");
exit(1);
}
/* now read result */
x = read(socket, (char *) &buf, sizeof(buf));
if (x < 1) {
perror("doproxyconnect: failed reading fra proxy");
exit(1);
}
/* no more error checking for now -- something should be added later */
/* HTTP/1.0 200 Connection established */
}
/* lwait for a connection and move into copyloop... again,
ftp redir will call this, so we don't dupilcate it. */
void
do_accept(int servsock, struct sockaddr_in *target)
{
int clisock;
int targetsock;
struct sockaddr_in client;
int clientlen = sizeof(client);
int accept_errno;
debug("top of accept loop\n");
if ((clisock = accept(servsock, (struct sockaddr *) &client,
&clientlen)) < 0) {
accept_errno = errno;
perror("server: accept");
if (dosyslog)
syslog(LOG_ERR, "accept failed: %m");
/* determine if this error is fatal */
switch(accept_errno) {
/* non-fatal errors */
case EHOSTUNREACH:
case ECONNRESET:
case ETIMEDOUT:
return;
/* all other errors assumed fatal */
default:
exit(1);
}
}
debug1("peer IP is %s\n", inet_ntoa(client.sin_addr));
debug1("peer socket is %d\n", client.sin_port);
/*
* Double fork here so we don't have to wait later
* This detaches us from our parent so that the parent
* does not need to pick up dead kids later.
*
* This needs to be done before the hosts_access stuff, because
* extended hosts_access options expect to be run from a child.
*/
switch(fork())
{
case -1: /* Error */
perror("(server) fork");
if (dosyslog)
syslog(LOG_ERR, "(server) fork failed: %m");
_exit(1);
case 0: /* Child */
break;
default: /* Parent */
{
int status;
/* Wait for child (who has forked off grandchild) */
(void) wait(&status);
/* Close sockets to prevent confusion */
close(clisock);
return;
}
}
/* We are now the first child. Fork again and exit */
switch(fork())
{
case -1: /* Error */
perror("(child) fork");
if (dosyslog)
syslog(LOG_ERR, "(child) fork failed: %m");
_exit(1);
case 0: /* Child */
break;
default: /* Parent */
_exit(0);
}
/* We are now the grandchild */
#ifdef USE_TCP_WRAPPERS
request_init(&request, RQ_DAEMON, ident, RQ_FILE, clisock, 0);
sock_host(&request);
sock_hostname(&request);
sock_hostaddr(&request);
if (!hosts_access(&request)) {
refuse(&request);
_exit(0);
}
if (dosyslog)
syslog(LOG_INFO, "accepted connect from %s", eval_client(&request));
#endif /* USE_TCP_WRAPPERS */
if ((targetsock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
perror("target: socket");
if (dosyslog)
syslog(LOG_ERR, "socket failed: %m");
_exit(1);
}
if(transproxy) {
memcpy(&addr_out, &client, sizeof(struct sockaddr_in));
addr_out.sin_port = 0;
}
if (bind_addr || transproxy) {
/* this only makes sense if an outgoing IP addr has been forced;
* at this point, we have a valid targetsock to bind() to.. */
/* also, if we're in transparent proxy mode, this option
never makes sense */
if (bind(targetsock, (struct sockaddr *) &addr_out,
sizeof(struct sockaddr_in)) < 0) {
perror("bind_addr: cannot bind to forcerd outgoing addr");
/* the port parameter fetch the really port we are listening, it should
only be different if the input value is 0 (let the system pick a
port) */
if (dosyslog)
syslog(LOG_ERR, "bind failed: %m");
_exit(1);
}
debug1("outgoing IP is %s\n", inet_ntoa(addr_out.sin_addr));
}
if (connect(targetsock, (struct sockaddr *) target,
sizeof(struct sockaddr_in)) < 0) {
perror("target: connect");
if (dosyslog)
syslog(LOG_ERR, "bind failed: %m");
_exit(1);
}
debug1("connected to %s\n", inet_ntoa(target->sin_addr));
/* thanks to Anders Vannman for the fix to make proper syslogging
happen here... */
if (dosyslog) {
char tmp1[20], tmp2[20];
strcpy(tmp1, inet_ntoa(client.sin_addr));
strcpy(tmp2, inet_ntoa(target->sin_addr));
syslog(LOG_NOTICE, "connecting %s/%d to %s/%d",
tmp1, client.sin_port,
tmp2, target->sin_port);
}
/* do proxy stuff */
if (connect_str)
doproxyconnect(targetsock);
#ifndef NO_SHAPER
/* initialise random number if necessary */
if( random_wait > 0 ) {
srand(getpid());
}
#endif
copyloop(clisock, targetsock, timeout);
exit(0); /* Exit after copy */
}
/* bind to a new socket, we do this out here because passive-fixups
are going to call it too, and there's no sense dupliciting the
code. */
/* fail is true if we should just return a -1 on error, false if we
should bail. */
int bindsock(char *addr, int port, int fail)
{
int servsock;
struct sockaddr_in server;
/*
* Get a socket to work with. This socket will
* be in the Internet domain, and will be a
* stream socket.
*/
if ((servsock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
if(fail) {
return -1;
}
else {
perror("server: socket");
if (dosyslog)
syslog(LOG_ERR, "socket failed: %m");
exit(1);
}
}
memset(&server, 0, sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(port);
if (addr != NULL) {
struct hostent *hp;
debug1("listening on %s\n", addr);
if ((hp = gethostbyname(addr)) == NULL) {
fprintf(stderr, "%s: cannot resolve hostname.\n", addr);
exit(1);
}
memcpy(&server.sin_addr, hp->h_addr, hp->h_length);
} else {
debug("local IP is default\n");
server.sin_addr.s_addr = htonl(inet_addr("0.0.0.0"));
}
setsockopt(servsock, SOL_SOCKET, SO_REUSEADDR, &reuse_addr, sizeof(reuse_addr));
setsockopt(servsock, SOL_SOCKET, SO_LINGER, &linger_opt, sizeof(SO_LINGER));
/*
* Try to bind the address to the socket.
*/
if (bind(servsock, (struct sockaddr *) &server,
sizeof(server)) < 0) {
if(fail) {
close(servsock);
return -1;
} else {
perror("server: bind");
if (dosyslog)
syslog(LOG_ERR, "bind failed: %m");
exit(1);
}
}
/*
* Listen on the socket.
*/
if (listen(servsock, 10) < 0) {
if(fail) {
close(servsock);
return -1;
} else {
perror("server: listen");
if (dosyslog)
syslog(LOG_ERR, "listen failed: %m");
exit(1);
}
}
return servsock;
}
int
main(int argc, char *argv[])
{
struct sockaddr_in target;
char *target_addr;
int target_port;
char *local_addr;
int local_port;
int inetd = 0;
char * target_ip;
char * ip_to_target;
debug("parse args\n");
parse_args(argc, argv, &target_addr, &target_port, &local_addr,
&local_port, &timeout, &dodebug, &inetd, &dosyslog, &bind_addr,