/*

main.c:

$Id$

Copyright (C) 2001-2010 Tomo.M (author).

All rights reserved.

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 author 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 AUTHOR 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 AUTHOR 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.

*/

#include <sys/stat.h>

#include "srelay.h"

/* prototypes */

void show_version __P((void));

void usage __P((void));

int serv_loop __P((void));

int validate_access __P((CL_INFO *));

char *config = CONFIG;

char *ident = "srelay";

char *pidfile = PIDFILE;

char *pwdfile = NULL;

char *bindtodevice = NULL;

char *bindout = NULL;

pid_t master_pid;

#if USE_THREAD

pthread_t main_thread;

int max_thread;

int threading;

#endif

int same_interface = 0;

#ifdef HAVE_LIBWRAP

int use_tcpwrap = 0;

# include <tcpd.h>

# if defined(LINUX) || defined(SOLARIS)

int allow_severity = LOG_AUTH|LOG_INFO;

int deny_severity = LOG_AUTH|LOG_NOTICE;

# endif /* LINUX */

extern int hosts_ctl __P((char *, char *, char *, char *));

#endif /* HAVE_LIBWRAP */

int max_child;

int cur_child;

int fg; /* foreground operation */

int inetd_mode = 0; /* inetd mode */

int bind_restrict = 1; /* socks bind port is restricted */

/* authentication method priority table */

char method_tab[10];

int method_num;

void show_version()

{

fprintf(stderr, "%s\n", version);

}

void usage()

{

show_version();

fprintf(stderr, "usage: %s [options]\n",

ident);

fprintf(stderr, "options:\n"

"\t-c file\tconfig file\n"

"\t-i i/f\tlisten interface IP[:PORT]\n"

#ifdef SO_BINDTODEVICE

"\t-J i/f\toutbound interface name\n"

#endif

"\t-x ipv4\tuse ipv4 literal for outbound connections (probably conflicts with -J and -g)\n"

"\t-m num\tmax child/thread\n"

"\t-o min\tidle timeout minutes\n"

"\t-p file\tpid file\n"

"\t-a np\tauth methods n: no, p:pass\n"

"\t-u file\tsrelay password file\n"

"\t-f\trun into foreground\n"

"\t-r\tresolve client name in log\n"

"\t-s\tforce logging to syslog\n"

"\t-t\tdisable threading\n"

"\t-b\tavoid BIND port restriction\n"

"\t-g\tuse the same interface for outbound as inbound\n"

#ifdef HAVE_LIBWRAP

"\t-w\tuse tcp_wrapper access control\n"

#endif /* HAVE_LIBWRAP */

"\t-I\tinetd mode\n"

"\t-q\twill be quiet\n"

"\t-v\tshow version and exit\n"

"\t-h\tshow this help and exit\n");

exit(1);

}

int validate_access(CL_INFO *client)

{

int stat = 0;

#ifdef HAVE_LIBWRAP

int i;

if ( use_tcpwrap ) {

/* proc ident pattern */

stat = hosts_ctl(ident, client->name, client->addr, STRING_UNKNOWN);

/* IP.PORT pattern */

for (i = 0; i < serv_sock_ind; i++) {

if (str_serv_sock[i] != NULL && str_serv_sock[i][0] != 0) {

stat |= hosts_ctl(str_serv_sock[i],

client->name, client->addr, STRING_UNKNOWN);

}

}

} else {

#endif /* HAVE_LIBWRAP */

stat = 1; /* allow access un-conditionaly */

#ifdef HAVE_LIBWRAP

}

#endif /* HAVE_LIBWRAP */

if (stat < 1) {

msg_out(warn, "%s[%s] access denied.", client->name, client->addr);

}

return stat;

}

#ifdef USE_THREAD

pthread_mutex_t mutex_select;

#endif

int serv_loop()

{

SOCKS_STATE state;

SOCK_INFO si;

CL_INFO client;

int cs;

fd_set readable;

int i, n, len;

int error;

pid_t pid;

memset(&state, 0, sizeof(state));

memset(&si, 0, sizeof(si));

memset(&client, 0, sizeof(client));

state.si = &si;

#ifdef USE_THREAD

if (threading) {

blocksignal(SIGHUP);

if (!fg)

blocksignal(SIGINT);

blocksignal(SIGUSR1);

}

#endif

for (;;) {

readable = allsock;

MUTEX_LOCK(mutex_select);

n = select(maxsock+1, &readable, 0, 0, 0);

if (n <= 0) {

if (n < 0 && errno != EINTR) {

msg_out(warn, "select: %m");

}

MUTEX_UNLOCK(mutex_select);

continue;

}

#ifdef USE_THREAD

if ( ! threading ) {

#endif

/* handle any queued signal flags */

if (FD_ISSET(sig_queue[0], &readable)) {

if (ioctl(sig_queue[0], FIONREAD, &i) != 0) {

msg_out(crit, "ioctl: %m");

exit(-1);

}

while (--i >= 0) {

char c;

if (read(sig_queue[0], &c, 1) != 1) {

msg_out(crit, "read: %m");

exit(-1);

}

switch(c) {

case 'H': /* sighup */

reload();

break;

case 'C': /* sigchld */

reapchild();

break;

case 'T': /* sigterm */

cleanup();

break;

default:

break;

}

}

}

#ifdef USE_THREAD

}

#endif

for ( i = 0; i < serv_sock_ind; i++ ) {

if (FD_ISSET(serv_sock[i], &readable)) {

n--;

break;

}

}

if ( n < 0 || i >= serv_sock_ind ) {

MUTEX_UNLOCK(mutex_select);

continue;

}

len = SS_LEN;

cs = accept(serv_sock[i], &si.prc.addr.sa, (socklen_t *)&len);

si.prc.len = len;

if (cs < 0) {

if (errno == EINTR

#ifdef SOLARIS

|| errno == EPROTO

#endif

|| errno == EWOULDBLOCK

|| errno == ECONNABORTED) {

; /* ignore */

} else {

/* real accept error */

msg_out(warn, "accept: %m");

}

MUTEX_UNLOCK(mutex_select);

continue;

}

MUTEX_UNLOCK(mutex_select);

#ifdef USE_THREAD

if ( !threading ) {

#endif

if (max_child > 0 && cur_child >= max_child) {

msg_out(warn, "child: cur %d; exeedeing max(%d)",

cur_child, max_child);

close(cs);

continue;

}

#ifdef USE_THREAD

}

#endif

/* get downstream-side socket name */

len = SS_LEN;

getsockname(cs, &si.myc.addr.sa, (socklen_t *)&len);

si.myc.len = len;

error = getnameinfo(&si.prc.addr.sa, si.prc.len,

client.addr, sizeof(client.addr),

NULL, 0,

NI_NUMERICHOST);

if (resolv_client) {

error = getnameinfo(&si.prc.addr.sa, si.prc.len,

client.name, sizeof(client.name),

NULL, 0, 0);

msg_out(norm, "%s[%s] connected", client.name, client.addr);

} else {

msg_out(norm, "%s connected", client.addr);

strncpy(client.name, client.addr, sizeof(client.name));

}

i = validate_access(&client);

if (i < 1) {

/* access denied */

close(cs);

continue;

}

set_blocking(cs);

state.s = cs;

#ifdef USE_THREAD

if (!threading ) {

#endif

blocksignal(SIGHUP);

blocksignal(SIGCHLD);

pid = fork();

switch (pid) {

case -1: /* fork child failed */

break;

case 0: /* i am child */

for ( i = 0; i < serv_sock_ind; i++ ) {

close(serv_sock[i]);

}

setsignal(SIGCHLD, SIG_DFL);

setsignal(SIGHUP, SIG_DFL);

releasesignal(SIGCHLD);

releasesignal(SIGHUP);

error = proto_socks(&state);

if ( error == -1 ) {

close(state.s); /* may already be closed */

exit(1);

}

relay(&state);

exit(0);

default: /* may be parent */

proclist_add(pid);

break;

}

close(state.s);

releasesignal(SIGHUP);

releasesignal(SIGCHLD);

#ifdef USE_THREAD

} else {

error = proto_socks(&state);

if ( error == -1 ) {

close(state.s); /* may already be closed */

/* udp may be dynamically allocated */

if (state.sr.udp != NULL)

free(state.sr.udp);

continue;

}

relay(&state);

}

#endif

}

}

int inetd_service(int cs)

{

SOCKS_STATE state;

SOCK_INFO si;

CL_INFO client;

int len;

int error;

memset(&state, 0, sizeof(state));

memset(&si, 0, sizeof(si));

state.si = &si;

/* get downstream-side socket name */

len = SS_LEN;

getsockname(cs, &si.myc.addr.sa, (socklen_t *)&len);

si.myc.len = len;

/* get downstream-side peer name */

len = SS_LEN;

getpeername(cs, &si.prc.addr.sa, (socklen_t *)&len);

si.prc.len = len;

error = getnameinfo(&si.prc.addr.sa, si.prc.len,

client.addr, sizeof(client.addr),

NULL, 0,

NI_NUMERICHOST);

if (resolv_client) {

error = getnameinfo(&si.prc.addr.sa, si.prc.len,

client.name, sizeof(client.name),

NULL, 0, 0);

msg_out(norm, "%s[%s] connected", client.name, client.addr);

} else {

msg_out(norm, "%s connected", client.addr);

strncpy(client.name, client.addr, sizeof(client.name));

}

set_blocking(cs);

state.s = cs;

error = proto_socks(&state);

if (error == -1) {

msg_out(warn, "socks proto error");

close(state.s);

if (state.sr.udp != NULL)

free(state.sr.udp);

return(-1);

}

/* start relaying */

relay(&state);

close(cs);

return(0);

}

int main(int ac, char **av)

{

int ch, i=0;

pid_t pid;

FILE *fp;

uid_t uid;

#ifdef USE_THREAD

pthread_t tid;

pthread_attr_t attr;

struct rlimit rl;

rlim_t max_fd = (rlim_t)MAX_FD;

rlim_t save_fd = 0;

#endif

#ifdef USE_THREAD

threading = 1;

max_thread = MAX_THREAD;

#endif

max_child = MAX_CHILD;

cur_child = 0;

/* create service socket table (malloc) */

if (serv_init(NULL) < 0) {

msg_out(crit, "cannot malloc: %m");

exit(-1);

}

proxy_tbl = NULL;

proxy_tbl_ind = 0;

method_num = 0;

uid = getuid();

openlog(ident, LOG_PID | LOG_NDELAY, SYSLOGFAC);

while((ch = getopt(ac, av, "a:c:i:x:J:m:o:p:u:frstbwgIqvh?")) != -1)

switch (ch) {

case 'a':

if (optarg != NULL) {

for (i=0; i<sizeof method_tab; optarg++) {

if (*optarg == '\0')

break;

switch (*optarg) {

case 'p':

if ( uid != 0 ) {

/* process does not started by root */

msg_out(warn, "uid == %d (!=0),"

"user/pass auth will not work, ignored.",

uid);

break;

}

method_tab[i++] = S5AUSRPAS;

method_num++;

break;

case 'n':

method_tab[i++] = S5ANOAUTH;

method_num++;

break;

default:

break;

}

}

}

break;

case 'b':

bind_restrict = 0;

break;

case 'c':

if (optarg != NULL) {

config = strdup(optarg);

}

break;

case 'u':

if (optarg != NULL) {

pwdfile = strdup(optarg);

}

break;

case 'i':

if (optarg != NULL) {

if (serv_init(optarg) < 0) {

msg_out(warn, "cannot init server socket(-i %s): %m", optarg);

break;

}

}

break;

#ifdef SO_BINDTODEVICE

case 'J':

if (optarg != NULL) {

bindtodevice = strdup(optarg);

}

break;

#endif

case 'x':

if (optarg != NULL) {

bindout = strdup(optarg);

}

break;

case 'o':

if (optarg != NULL) {

idle_timeout = atol(optarg);

}

break;

case 'p':

if (optarg != NULL) {

pidfile = strdup(optarg);

}

break;

case 'm':

if (optarg != NULL) {

#ifdef USE_THREAD

max_thread = atoi(optarg);

#endif

max_child = atoi(optarg);

}

break;

case 't':

#ifdef USE_THREAD

threading = 0; /* threading disabled. */

#endif

break;

case 'g':

same_interface = 1;

break;

case 'f':

fg = 1;

break;

case 'r':

resolv_client = 1;

break;

case 's':

forcesyslog = 1;

break;

case 'w':

#ifdef HAVE_LIBWRAP

use_tcpwrap = 1;

#endif /* HAVE_LIBWRAP */

break;

case 'I':

inetd_mode = 1;

break;

case 'q':

be_quiet = 1;

break;

case 'v':

show_version();

exit(1);

case 'h':

case '?':

default:

usage();

}

ac -= optind;

av += optind;

if (fg && !forcesyslog && isatty(fileno(stderr)))

setvbuf(stderr, NULL, _IOLBF, 0);

if ((fp = fopen(config, "r")) != NULL) {

if (readconf(fp) != 0) {

/* readconf error */

exit(1);

}

fclose(fp);

}

if (inetd_mode) {

/* close all server socket if opened */

close_all_serv();

/* assuming that STDIN_FILENO handles bi-directional

*/

exit(inetd_service(STDIN_FILENO));

/* not reached */

}

if (serv_sock_ind == 0) { /* no valid ifs yet */

if (serv_init(":") < 0) { /* use default */

/* fatal */

msg_out(crit, "cannot open server socket");

exit(1);

}

}

#ifdef USE_THREAD

if ( ! threading ) {

#endif

if (queue_init() != 0) {

msg_out(crit, "cannot init signal queue");

exit(1);

}

#ifdef USE_THREAD

}

#endif

/* try changing working directory */

if ( chdir(WORKDIR0) != 0 )

if ( chdir(WORKDIR1) != 0 )

msg_out(norm, "giving up chdir to workdir");

if (!fg) {

/* force stdin/out/err allocate to /dev/null */

fclose(stdin);

fp = fopen("/dev/null", "w+");

if (fileno(fp) != STDIN_FILENO) {

msg_out(crit, "fopen: %m");

exit(1);

}

if (dup2(STDIN_FILENO, STDOUT_FILENO) == -1) {

msg_out(crit, "dup2-1: %m");

exit(1);

}

if (dup2(STDIN_FILENO, STDERR_FILENO) == -1) {

msg_out(crit, "dup2-2: %m");

exit(1);

}

switch(fork()) {

case -1:

msg_out(crit, "fork: %m");

exit(1);

case 0:

/* child */

pid = setsid();

if (pid == -1) {

msg_out(crit, "setsid: %m");

exit(1);

}

break;

default:

/* parent */

exit(0);

}

}

master_pid = getpid();

umask(S_IWGRP|S_IWOTH);

if ((fp = fopen(pidfile, "w")) != NULL) {

fprintf(fp, "%u\n", (unsigned)master_pid);

fchown(fileno(fp), PROCUID, PROCGID);

fclose(fp);

} else {

msg_out(warn, "cannot open pidfile %s", pidfile);

}

setsignal(SIGHUP, reload);

if (fg)

setsignal(SIGINT, cleanup);

else

setsignal(SIGINT, SIG_IGN);

setsignal(SIGQUIT, SIG_IGN);

setsignal(SIGILL, SIG_IGN);

setsignal(SIGTRAP, SIG_IGN);

setsignal(SIGABRT, SIG_IGN);

#ifdef SIGEMT

setsignal(SIGEMT, SIG_IGN);

#endif

setsignal(SIGSYS, SIG_IGN);

setsignal(SIGPIPE, SIG_IGN);

setsignal(SIGALRM, SIG_IGN);

setsignal(SIGTERM, cleanup);

setsignal(SIGUSR1, SIG_IGN);

setsignal(SIGUSR2, SIG_IGN);

#ifdef SIGPOLL

setsignal(SIGPOLL, SIG_IGN);

#endif

setsignal(SIGVTALRM, SIG_IGN);

setsignal(SIGPROF, SIG_IGN);

setsignal(SIGXCPU, SIG_IGN);

setsignal(SIGXFSZ, SIG_IGN);

#ifdef USE_THREAD

if ( threading ) {

if (max_thread <= 0 || max_thread > THREAD_LIMIT) {

max_thread = THREAD_LIMIT;

}

/* resource limit is problem in threadig (e.g. Solaris:=64)*/

memset((caddr_t)&rl, 0, sizeof rl);

if (getrlimit(RLIMIT_NOFILE, &rl) != 0)

msg_out(warn, "getrlimit: %m");

else

save_fd = rl.rlim_cur;

if (rl.rlim_cur < (rlim_t)max_fd)

rl.rlim_cur = max_fd; /* willing to fix to max_fd */

if ( rl.rlim_cur != save_fd ) /* if rlim_cur is changed */

if (setrlimit(RLIMIT_NOFILE, &rl) != 0)

msg_out(warn, "cannot set rlimit(max_fd)");

setregid(0, PROCGID);

setreuid(0, PROCUID);

pthread_mutex_init(&mutex_select, NULL);

pthread_attr_init(&attr);

pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);

msg_out(norm, "Starting: MAX_TH(%d)", max_thread);

for (i=0; i<max_thread; i++) {

if (pthread_create(&tid, &attr,

(void *)&serv_loop, (void *)NULL) != 0)

exit(1);

}

main_thread = pthread_self(); /* store main thread ID */

for (;;) {

pause();

}

} else {

#endif

setsignal(SIGCHLD, reapchild);

setregid(0, PROCGID);

setreuid(0, PROCUID);

msg_out(norm, "Starting: MAX_CH(%d)", max_child);

serv_loop();

#ifdef USE_THREAD

}

#endif

return(0);

}