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0641086c2f
curl/tests/server/socksd.c
Daniel Gustafsson 0641086c2f socksd: Fix typos 
Reviewed-by: Daniel Stenberg <daniel@haxx.se>
2019-04-14 22:06:40 +02:00

1165 lines
31 KiB
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "server_setup.h"
#include <stdlib.h>
/* Function
*
* Accepts a TCP connection on a custom port (IPv4 or IPv6). Connects to a
* given addr + port backend (that is NOT extracted form the client's
* request). The backend server default to connect to can be set with
* --backend and --backendport.
*
* Read commands from FILE (set with --config). The commands control how to
* act and is reset to defaults each client TCP connect.
*
* Config file keywords:
*
* "version [number: 5]" - requires the communication to use this version.
* "nmethods_min [number: 1]" - the minimum numberf NMETHODS the client must
* state
* "nmethods_max [number: 3]" - the minimum numberf NMETHODS the client must
* state
* "user [string]" - the user name that must match (if method is 2)
* "password [string]" - the password that must match (if method is 2)
* "backend [IPv4]" - numerical IPv4 address of backend to connect to
* "backendport [number:0]" - TCP port of backend to connect to. 0 means use
the client's specified port number.
* "method [number: 0]" - connect method to respond with:
* 0 - no auth
* 1 - GSSAPI (not supported)
* 2 - user + password
* "response [number]" - the decimal number to repsond to a connect
* SOCKS5: 0 is OK, SOCKS4: 90 is ok
*
*/
/* based on sockfilt.c */
#ifdef HAVE_SIGNAL_H
#include <signal.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETINET_IN6_H
#include <netinet/in6.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#define ENABLE_CURLX_PRINTF
/* make the curlx header define all printf() functions to use the curlx_*
versions instead */
#include "curlx.h" /* from the private lib dir */
#include "getpart.h"
#include "inet_pton.h"
#include "util.h"
#include "server_sockaddr.h"
#include "warnless.h"
/* include memdebug.h last */
#include "memdebug.h"
#ifdef USE_WINSOCK
#undef EINTR
#define EINTR 4 /* errno.h value */
#undef EAGAIN
#define EAGAIN 11 /* errno.h value */
#undef ENOMEM
#define ENOMEM 12 /* errno.h value */
#undef EINVAL
#define EINVAL 22 /* errno.h value */
#endif
#define DEFAULT_PORT 8905
#ifndef DEFAULT_LOGFILE
#define DEFAULT_LOGFILE "log/socksd.log"
#endif
#ifndef DEFAULT_CONFIG
#define DEFAULT_CONFIG "socksd.config"
#endif
static const char *backendaddr = "127.0.0.1";
static unsigned short backendport = 0; /* default is use client's */
struct configurable {
unsigned char version; /* initial version byte in the request must match
this */
unsigned char nmethods_min; /* minimum number of nmethods to expect */
unsigned char nmethods_max; /* maximum number of nmethods to expect */
unsigned char responseversion;
unsigned char responsemethod;
unsigned char reqcmd;
unsigned char connectrep;
unsigned short port; /* backend port */
char addr[32]; /* backend IPv4 numerical */
char user[256];
char password[256];
};
#define CONFIG_VERSION 5
#define CONFIG_NMETHODS_MIN 1 /* unauth, gssapi, auth */
#define CONFIG_NMETHODS_MAX 3
#define CONFIG_RESPONSEVERSION CONFIG_VERSION
#define CONFIG_RESPONSEMETHOD 0 /* no auth */
#define CONFIG_REQCMD 1 /* CONNECT */
#define CONFIG_PORT backendport
#define CONFIG_ADDR backendaddr
#define CONFIG_CONNECTREP 0
static struct configurable config;
const char *serverlogfile = DEFAULT_LOGFILE;
static const char *configfile = DEFAULT_CONFIG;
#ifdef ENABLE_IPV6
static bool use_ipv6 = FALSE;
#endif
static const char *ipv_inuse = "IPv4";
static unsigned short port = DEFAULT_PORT;
static void resetdefaults(void)
{
logmsg("Reset to defaults");
config.version = CONFIG_VERSION;
config.nmethods_min = CONFIG_NMETHODS_MIN;
config.nmethods_max = CONFIG_NMETHODS_MAX;
config.responseversion = CONFIG_RESPONSEVERSION;
config.responsemethod = CONFIG_RESPONSEMETHOD;
config.reqcmd = CONFIG_REQCMD;
config.connectrep = CONFIG_CONNECTREP;
config.port = CONFIG_PORT;
strcpy(config.addr, CONFIG_ADDR);
strcpy(config.user, "user");
strcpy(config.password, "password");
}
static unsigned char byteval(char *value)
{
unsigned long num = strtoul(value, NULL, 10);
return num & 0xff;
}
static unsigned short shortval(char *value)
{
unsigned long num = strtoul(value, NULL, 10);
return num & 0xffff;
}
static void getconfig(void)
{
FILE *fp = fopen(configfile, FOPEN_READTEXT);
resetdefaults();
if(fp) {
char buffer[512];
logmsg("parse config file");
while(fgets(buffer, sizeof(buffer), fp)) {
char key[32];
char value[32];
if(2 == sscanf(buffer, "%31s %31s", key, value)) {
if(!strcmp(key, "version")) {
config.version = byteval(value);
logmsg("version [%d] set", config.version);
}
else if(!strcmp(key, "nmethods_min")) {
config.nmethods_min = byteval(value);
logmsg("nmethods_min [%d] set", config.nmethods_min);
}
else if(!strcmp(key, "nmethods_max")) {
config.nmethods_max = byteval(value);
logmsg("nmethods_max [%d] set", config.nmethods_max);
}
else if(!strcmp(key, "backend")) {
strcpy(config.addr, value);
logmsg("backend [%s] set", config.addr);
}
else if(!strcmp(key, "backendport")) {
config.port = shortval(value);
logmsg("backendport [%d] set", config.port);
}
else if(!strcmp(key, "user")) {
strcpy(config.user, value);
logmsg("user [%s] set", config.user);
}
else if(!strcmp(key, "password")) {
strcpy(config.password, value);
logmsg("password [%s] set", config.password);
}
/* Methods:
o X'00' NO AUTHENTICATION REQUIRED
o X'01' GSSAPI
o X'02' USERNAME/PASSWORD
*/
else if(!strcmp(key, "method")) {
config.responsemethod = byteval(value);
logmsg("method [%d] set", config.responsemethod);
}
else if(!strcmp(key, "response")) {
config.connectrep = byteval(value);
logmsg("response [%d] set", config.connectrep);
}
}
}
fclose(fp);
}
}
/* do-nothing macro replacement for systems which lack siginterrupt() */
#ifndef HAVE_SIGINTERRUPT
#define siginterrupt(x,y) do {} while(0)
#endif
/* vars used to keep around previous signal handlers */
typedef RETSIGTYPE (*SIGHANDLER_T)(int);
#ifdef SIGHUP
static SIGHANDLER_T old_sighup_handler = SIG_ERR;
#endif
#ifdef SIGPIPE
static SIGHANDLER_T old_sigpipe_handler = SIG_ERR;
#endif
#ifdef SIGALRM
static SIGHANDLER_T old_sigalrm_handler = SIG_ERR;
#endif
#ifdef SIGINT
static SIGHANDLER_T old_sigint_handler = SIG_ERR;
#endif
#if defined(SIGBREAK) && defined(WIN32)
static SIGHANDLER_T old_sigbreak_handler = SIG_ERR;
#endif
/* var which if set indicates that the program should finish execution */
SIG_ATOMIC_T got_exit_signal = 0;
/* if next is set indicates the first signal handled in exit_signal_handler */
static volatile int exit_signal = 0;
/* signal handler that will be triggered to indicate that the program
should finish its execution in a controlled manner as soon as possible.
The first time this is called it will set got_exit_signal to one and
store in exit_signal the signal that triggered its execution. */
static RETSIGTYPE exit_signal_handler(int signum)
{
int old_errno = errno;
if(got_exit_signal == 0) {
got_exit_signal = 1;
exit_signal = signum;
}
(void)signal(signum, exit_signal_handler);
errno = old_errno;
}
static void install_signal_handlers(void)
{
#ifdef SIGHUP
/* ignore SIGHUP signal */
old_sighup_handler = signal(SIGHUP, SIG_IGN);
if(old_sighup_handler == SIG_ERR)
logmsg("cannot install SIGHUP handler: %s", strerror(errno));
#endif
#ifdef SIGPIPE
/* ignore SIGPIPE signal */
old_sigpipe_handler = signal(SIGPIPE, SIG_IGN);
if(old_sigpipe_handler == SIG_ERR)
logmsg("cannot install SIGPIPE handler: %s", strerror(errno));
#endif
#ifdef SIGALRM
/* ignore SIGALRM signal */
old_sigalrm_handler = signal(SIGALRM, SIG_IGN);
if(old_sigalrm_handler == SIG_ERR)
logmsg("cannot install SIGALRM handler: %s", strerror(errno));
#endif
#ifdef SIGINT
/* handle SIGINT signal with our exit_signal_handler */
old_sigint_handler = signal(SIGINT, exit_signal_handler);
if(old_sigint_handler == SIG_ERR)
logmsg("cannot install SIGINT handler: %s", strerror(errno));
else
siginterrupt(SIGINT, 1);
#endif
#if defined(SIGBREAK) && defined(WIN32)
/* handle SIGBREAK signal with our exit_signal_handler */
old_sigbreak_handler = signal(SIGBREAK, exit_signal_handler);
if(old_sigbreak_handler == SIG_ERR)
logmsg("cannot install SIGBREAK handler: %s", strerror(errno));
else
siginterrupt(SIGBREAK, 1);
#endif
}
static void restore_signal_handlers(void)
{
#ifdef SIGHUP
if(SIG_ERR != old_sighup_handler)
(void)signal(SIGHUP, old_sighup_handler);
#endif
#ifdef SIGPIPE
if(SIG_ERR != old_sigpipe_handler)
(void)signal(SIGPIPE, old_sigpipe_handler);
#endif
#ifdef SIGALRM
if(SIG_ERR != old_sigalrm_handler)
(void)signal(SIGALRM, old_sigalrm_handler);
#endif
#ifdef SIGINT
if(SIG_ERR != old_sigint_handler)
(void)signal(SIGINT, old_sigint_handler);
#endif
#if defined(SIGBREAK) && defined(WIN32)
if(SIG_ERR != old_sigbreak_handler)
(void)signal(SIGBREAK, old_sigbreak_handler);
#endif
}
static void loghex(unsigned char *buffer, ssize_t len)
{
char data[1200];
ssize_t i;
unsigned char *ptr = buffer;
char *optr = data;
ssize_t width = 0;
int left = sizeof(data);
for(i = 0; i<len && (left >= 0); i++) {
msnprintf(optr, left, "%02x", ptr[i]);
width += 2;
optr += 2;
left -= 2;
}
if(width)
logmsg("'%s'", data);
}
/* RFC 1928, SOCKS5 byte index */
#define SOCKS5_VERSION 0
#define SOCKS5_NMETHODS 1 /* number of methods that is listed */
/* in the request: */
#define SOCKS5_REQCMD 1
#define SOCKS5_RESERVED 2
#define SOCKS5_ATYP 3
#define SOCKS5_DSTADDR 4
/* connect response */
#define SOCKS5_REP 1
#define SOCKS5_BNDADDR 4
/* auth request */
#define SOCKS5_ULEN 1
#define SOCKS5_UNAME 2
#define SOCKS4_CD 1
#define SOCKS4_DSTPORT 2
/* connect to a given IPv4 address, not the one asked for */
static curl_socket_t socksconnect(unsigned short connectport,
const char *connectaddr)
{
int rc;
srvr_sockaddr_union_t me;
curl_socket_t sock = socket(AF_INET, SOCK_STREAM, 0);
if(sock == CURL_SOCKET_BAD)
return CURL_SOCKET_BAD;
memset(&me.sa4, 0, sizeof(me.sa4));
me.sa4.sin_family = AF_INET;
me.sa4.sin_port = htons(connectport);
me.sa4.sin_addr.s_addr = INADDR_ANY;
Curl_inet_pton(AF_INET, connectaddr, &me.sa4.sin_addr);
rc = connect(sock, &me.sa, sizeof(me.sa4));
if(rc) {
int error = SOCKERRNO;
logmsg("Error connecting to %s:%hu: (%d) %s",
connectaddr, connectport, error, strerror(error));
return CURL_SOCKET_BAD;
}
logmsg("Connected fine to %s:%d", connectaddr, connectport);
return sock;
}
static curl_socket_t socks4(curl_socket_t fd,
unsigned char *buffer,
ssize_t rc)
{
unsigned char response[256 + 16];
curl_socket_t connfd;
unsigned char cd;
unsigned short s4port;
if(buffer[SOCKS4_CD] != 1) {
logmsg("SOCKS4 CD is not 1: %d", buffer[SOCKS4_CD]);
return CURL_SOCKET_BAD;
}
if(rc < 9) {
logmsg("SOCKS4 connect message too short: %d", rc);
return CURL_SOCKET_BAD;
}
if(!config.port)
s4port = (unsigned short)((buffer[SOCKS4_DSTPORT]<<8) |
(buffer[SOCKS4_DSTPORT + 1]));
else
s4port = config.port;
connfd = socksconnect(s4port, config.addr);
if(connfd == CURL_SOCKET_BAD) {
/* failed */
cd = 91;
}
else {
/* success */
cd = 90;
}
response[0] = 0; /* reply version 0 */
response[1] = cd; /* result */
/* copy port and address from connect request */
memcpy(&response[2], &buffer[SOCKS4_DSTPORT], 6);
rc = (send)(fd, (char *)response, 8, 0);
if(rc != 8) {
logmsg("Sending SOCKS4 response failed!");
return CURL_SOCKET_BAD;
}
logmsg("Sent %d bytes", rc);
loghex(response, rc);
if(cd == 90)
/* now do the transfer */
return connfd;
if(connfd != CURL_SOCKET_BAD)
sclose(connfd);
return CURL_SOCKET_BAD;
}
static curl_socket_t sockit(curl_socket_t fd)
{
unsigned char buffer[256 + 16];
unsigned char response[256 + 16];
ssize_t rc;
unsigned char len;
unsigned char type;
unsigned char rep = 0;
unsigned char *address;
unsigned short socksport;
curl_socket_t connfd = CURL_SOCKET_BAD;
unsigned short s5port;
getconfig();
rc = recv(fd, (char *)buffer, sizeof(buffer), 0);
logmsg("READ %d bytes", rc);
loghex(buffer, rc);
if(buffer[SOCKS5_VERSION] == 4)
return socks4(fd, buffer, rc);
if(buffer[SOCKS5_VERSION] != config.version) {
logmsg("VERSION byte not %d", config.version);
return CURL_SOCKET_BAD;
}
if((buffer[SOCKS5_NMETHODS] < config.nmethods_min) ||
(buffer[SOCKS5_NMETHODS] > config.nmethods_max)) {
logmsg("NMETHODS byte not within %d - %d ",
config.nmethods_min, config.nmethods_max);
return CURL_SOCKET_BAD;
}
/* after NMETHODS follows that many bytes listing the methods the client
says it supports */
if(rc != (buffer[SOCKS5_NMETHODS] + 2)) {
logmsg("Expected %d bytes, got %d", buffer[SOCKS5_NMETHODS] + 2, rc);
return CURL_SOCKET_BAD;
}
logmsg("Incoming request deemed fine!");
/* respond with two bytes: VERSION + METHOD */
response[0] = config.responseversion;
response[1] = config.responsemethod;
rc = (send)(fd, (char *)response, 2, 0);
if(rc != 2) {
logmsg("Sending response failed!");
return CURL_SOCKET_BAD;
}
logmsg("Sent %d bytes", rc);
loghex(response, rc);
/* expect the request or auth */
rc = recv(fd, (char *)buffer, sizeof(buffer), 0);
logmsg("READ %d bytes", rc);
loghex(buffer, rc);
if(config.responsemethod == 2) {
/* RFC 1929 authentication
+----+------+----------+------+----------+
|VER | ULEN | UNAME | PLEN | PASSWD |
+----+------+----------+------+----------+
| 1 | 1 | 1 to 255 | 1 | 1 to 255 |
+----+------+----------+------+----------+
*/
unsigned char ulen;
unsigned char plen;
bool login = TRUE;
if(rc < 5) {
logmsg("Too short auth input: %d", rc);
return CURL_SOCKET_BAD;
}
if(buffer[SOCKS5_VERSION] != 1) {
logmsg("Auth VERSION byte not 1, got %d", buffer[SOCKS5_VERSION]);
return CURL_SOCKET_BAD;
}
ulen = buffer[SOCKS5_ULEN];
if(rc < 4 + ulen) {
logmsg("Too short packet for username: %d", rc);
return CURL_SOCKET_BAD;
}
plen = buffer[SOCKS5_ULEN + ulen + 1];
if(rc < 3 + ulen + plen) {
logmsg("Too short packet for ulen %d plen %d: %d", ulen, plen, rc);
return CURL_SOCKET_BAD;
}
if((ulen != strlen(config.user)) ||
(plen != strlen(config.password)) ||
memcmp(&buffer[SOCKS5_UNAME], config.user, ulen) ||
memcmp(&buffer[SOCKS5_UNAME + ulen + 1], config.password, plen)) {
/* no match! */
logmsg("mismatched credentials!");
login = FALSE;
}
response[0] = 1;
response[1] = login ? 0 : 1;
rc = (send)(fd, (char *)response, 2, 0);
if(rc != 2) {
logmsg("Sending auth response failed!");
return CURL_SOCKET_BAD;
}
logmsg("Sent %d bytes", rc);
loghex(response, rc);
if(!login)
return CURL_SOCKET_BAD;
/* expect the request */
rc = recv(fd, (char *)buffer, sizeof(buffer), 0);
logmsg("READ %d bytes", rc);
loghex(buffer, rc);
}
if(rc < 6) {
logmsg("Too short for request: %d", rc);
return CURL_SOCKET_BAD;
}
if(buffer[SOCKS5_VERSION] != config.version) {
logmsg("Request VERSION byte not %d", config.version);
return CURL_SOCKET_BAD;
}
/* 1 == CONNECT */
if(buffer[SOCKS5_REQCMD] != config.reqcmd) {
logmsg("Request COMMAND byte not %d", config.reqcmd);
return CURL_SOCKET_BAD;
}
/* reserved, should be zero */
if(buffer[SOCKS5_RESERVED] != 0) {
logmsg("Request COMMAND byte not %d", config.reqcmd);
return CURL_SOCKET_BAD;
}
/* ATYP:
o IP V4 address: X'01'
o DOMAINNAME: X'03'
o IP V6 address: X'04'
*/
type = buffer[SOCKS5_ATYP];
address = &buffer[SOCKS5_DSTADDR];
switch(type) {
case 1:
/* 4 bytes IPv4 address */
len = 4;
break;
case 3:
/* The first octet of the address field contains the number of octets of
name that follow */
len = buffer[SOCKS5_DSTADDR];
len++;
break;
case 4:
/* 16 bytes IPv6 address */
len = 16;
break;
default:
logmsg("Unknown ATYP %d", type);
return CURL_SOCKET_BAD;
}
if(rc < (4 + len + 2)) {
logmsg("Request too short: %d, expected %d", rc, 4 + len + 2);
return CURL_SOCKET_BAD;
}
if(!config.port) {
unsigned char *portp = &buffer[SOCKS5_DSTADDR + len];
s5port = (unsigned short)((portp[0]<<8) | (portp[1]));
}
else
s5port = config.port;
if(!config.connectrep)
connfd = socksconnect(s5port, config.addr);
if(connfd == CURL_SOCKET_BAD) {
/* failed */
rep = 1;
}
else {
rep = config.connectrep;
}
/* */
response[SOCKS5_VERSION] = config.responseversion;
/*
o REP Reply field:
o X'00' succeeded
o X'01' general SOCKS server failure
o X'02' connection not allowed by ruleset
o X'03' Network unreachable
o X'04' Host unreachable
o X'05' Connection refused
o X'06' TTL expired
o X'07' Command not supported
o X'08' Address type not supported
o X'09' to X'FF' unassigned
*/
response[SOCKS5_REP] = rep;
response[SOCKS5_RESERVED] = 0; /* must be zero */
response[SOCKS5_ATYP] = type; /* address type */
/* mirror back the original addr + port */
/* address or hostname */
memcpy(&response[SOCKS5_BNDADDR], address, len);
/* port number */
memcpy(&response[SOCKS5_BNDADDR + len],
&buffer[SOCKS5_DSTADDR + len], sizeof(socksport));
rc = (send)(fd, (char *)response, len + 6, 0);
if(rc != (len + 6)) {
logmsg("Sending connect response failed!");
return CURL_SOCKET_BAD;
}
logmsg("Sent %d bytes", rc);
loghex(response, rc);
if(!rep)
return connfd;
if(connfd != CURL_SOCKET_BAD)
sclose(connfd);
return CURL_SOCKET_BAD;
}
struct perclient {
size_t fromremote;
size_t fromclient;
curl_socket_t remotefd;
curl_socket_t clientfd;
bool used;
};
/* return non-zero when transfer is done */
static int tunnel(struct perclient *cp, fd_set *fds)
{
ssize_t nread;
ssize_t nwrite;
char buffer[512];
if(FD_ISSET(cp->clientfd, fds)) {
/* read from client, send to remote */
nread = recv(cp->clientfd, buffer, sizeof(buffer), 0);
if(nread > 0) {
nwrite = send(cp->remotefd, (char *)buffer,
(SEND_TYPE_ARG3)nread, 0);
if(nwrite != nread)
return 1;
cp->fromclient += nwrite;
}
else
return 1;
}
if(FD_ISSET(cp->remotefd, fds)) {
/* read from remote, send to client */
nread = recv(cp->remotefd, buffer, sizeof(buffer), 0);
if(nread > 0) {
nwrite = send(cp->clientfd, (char *)buffer,
(SEND_TYPE_ARG3)nread, 0);
if(nwrite != nread)
return 1;
cp->fromremote += nwrite;
}
else
return 1;
}
return 0;
}
/*
sockfdp is a pointer to an established stream or CURL_SOCKET_BAD
if sockfd is CURL_SOCKET_BAD, listendfd is a listening socket we must
accept()
*/
static bool incoming(curl_socket_t listenfd)
{
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
curl_socket_t sockfd = CURL_SOCKET_BAD;
int maxfd = -99;
ssize_t rc;
int error = 0;
int clients = 0; /* connected clients */
struct perclient c[2];
memset(c, 0, sizeof(c));
if(got_exit_signal) {
logmsg("signalled to die, exiting...");
return FALSE;
}
#ifdef HAVE_GETPPID
/* As a last resort, quit if socks5 process becomes orphan. */
if(getppid() <= 1) {
logmsg("process becomes orphan, exiting");
return FALSE;
}
#endif
do {
int i;
FD_ZERO(&fds_read);
FD_ZERO(&fds_write);
FD_ZERO(&fds_err);
sockfd = listenfd;
/* there's always a socket to wait for */
FD_SET(sockfd, &fds_read);
maxfd = (int)sockfd;
for(i = 0; i < 2; i++) {
if(c[i].used) {
curl_socket_t fd = c[i].clientfd;
FD_SET(fd, &fds_read);
if((int)fd > maxfd)
maxfd = (int)fd;
fd = c[i].remotefd;
FD_SET(fd, &fds_read);
if((int)fd > maxfd)
maxfd = (int)fd;
}
}
do {
/* select() blocking behavior call on blocking descriptors please */
rc = select(maxfd + 1, &fds_read, &fds_write, &fds_err, NULL);
if(got_exit_signal) {
logmsg("signalled to die, exiting...");
return FALSE;
}
} while((rc == -1) && ((error = errno) == EINTR));
if(rc < 0) {
logmsg("select() failed with error: (%d) %s",
error, strerror(error));
return FALSE;
}
if((clients < 2) && FD_ISSET(sockfd, &fds_read)) {
curl_socket_t newfd = accept(sockfd, NULL, NULL);
if(CURL_SOCKET_BAD == newfd) {
error = SOCKERRNO;
logmsg("accept(%d, NULL, NULL) failed with error: (%d) %s",
sockfd, error, strerror(error));
}
else {
curl_socket_t remotefd;
logmsg("====> Client connect, fd %d. Read config from %s",
newfd, configfile);
remotefd = sockit(newfd); /* SOCKS until done */
if(remotefd == CURL_SOCKET_BAD) {
logmsg("====> Client disconnect");
sclose(newfd);
}
else {
struct perclient *cp = &c[0];
logmsg("====> Tunnel transfer");
if(c[0].used)
cp = &c[1];
cp->fromremote = 0;
cp->fromclient = 0;
cp->clientfd = newfd;
cp->remotefd = remotefd;
cp->used = TRUE;
clients++;
}
}
}
for(i = 0; i < 2; i++) {
struct perclient *cp = &c[i];
if(cp->used) {
if(tunnel(cp, &fds_read)) {
logmsg("SOCKS transfer completed. Bytes: < %zu > %zu",
cp->fromremote, cp->fromclient);
sclose(cp->clientfd);
sclose(cp->remotefd);
cp->used = FALSE;
clients--;
}
}
}
} while(clients);
return TRUE;
}
static curl_socket_t sockdaemon(curl_socket_t sock,
unsigned short *listenport)
{
/* passive daemon style */
srvr_sockaddr_union_t listener;
int flag;
int rc;
int totdelay = 0;
int maxretr = 10;
int delay = 20;
int attempt = 0;
int error = 0;
do {
attempt++;
flag = 1;
rc = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
(void *)&flag, sizeof(flag));
if(rc) {
error = SOCKERRNO;
logmsg("setsockopt(SO_REUSEADDR) failed with error: (%d) %s",
error, strerror(error));
if(maxretr) {
rc = wait_ms(delay);
if(rc) {
/* should not happen */
error = errno;
logmsg("wait_ms() failed with error: (%d) %s",
error, strerror(error));
sclose(sock);
return CURL_SOCKET_BAD;
}
if(got_exit_signal) {
logmsg("signalled to die, exiting...");
sclose(sock);
return CURL_SOCKET_BAD;
}
totdelay += delay;
delay *= 2; /* double the sleep for next attempt */
}
}
} while(rc && maxretr--);
if(rc) {
logmsg("setsockopt(SO_REUSEADDR) failed %d times in %d ms. Error: (%d) %s",
attempt, totdelay, error, strerror(error));
logmsg("Continuing anyway...");
}
/* When the specified listener port is zero, it is actually a
request to let the system choose a non-zero available port. */
#ifdef ENABLE_IPV6
if(!use_ipv6) {
#endif
memset(&listener.sa4, 0, sizeof(listener.sa4));
listener.sa4.sin_family = AF_INET;
listener.sa4.sin_addr.s_addr = INADDR_ANY;
listener.sa4.sin_port = htons(*listenport);
rc = bind(sock, &listener.sa, sizeof(listener.sa4));
#ifdef ENABLE_IPV6
}
else {
memset(&listener.sa6, 0, sizeof(listener.sa6));
listener.sa6.sin6_family = AF_INET6;
listener.sa6.sin6_addr = in6addr_any;
listener.sa6.sin6_port = htons(*listenport);
rc = bind(sock, &listener.sa, sizeof(listener.sa6));
}
#endif /* ENABLE_IPV6 */
if(rc) {
error = SOCKERRNO;
logmsg("Error binding socket on port %hu: (%d) %s",
*listenport, error, strerror(error));
sclose(sock);
return CURL_SOCKET_BAD;
}
if(!*listenport) {
/* The system was supposed to choose a port number, figure out which
port we actually got and update the listener port value with it. */
curl_socklen_t la_size;
srvr_sockaddr_union_t localaddr;
#ifdef ENABLE_IPV6
if(!use_ipv6)
#endif
la_size = sizeof(localaddr.sa4);
#ifdef ENABLE_IPV6
else
la_size = sizeof(localaddr.sa6);
#endif
memset(&localaddr.sa, 0, (size_t)la_size);
if(getsockname(sock, &localaddr.sa, &la_size) < 0) {
error = SOCKERRNO;
logmsg("getsockname() failed with error: (%d) %s",
error, strerror(error));
sclose(sock);
return CURL_SOCKET_BAD;
}
switch(localaddr.sa.sa_family) {
case AF_INET:
*listenport = ntohs(localaddr.sa4.sin_port);
break;
#ifdef ENABLE_IPV6
case AF_INET6:
*listenport = ntohs(localaddr.sa6.sin6_port);
break;
#endif
default:
break;
}
if(!*listenport) {
/* Real failure, listener port shall not be zero beyond this point. */
logmsg("Apparently getsockname() succeeded, with listener port zero.");
logmsg("A valid reason for this failure is a binary built without");
logmsg("proper network library linkage. This might not be the only");
logmsg("reason, but double check it before anything else.");
sclose(sock);
return CURL_SOCKET_BAD;
}
}
/* start accepting connections */
rc = listen(sock, 5);
if(0 != rc) {
error = SOCKERRNO;
logmsg("listen(%d, 5) failed with error: (%d) %s",
sock, error, strerror(error));
sclose(sock);
return CURL_SOCKET_BAD;
}
return sock;
}
int main(int argc, char *argv[])
{
curl_socket_t sock = CURL_SOCKET_BAD;
curl_socket_t msgsock = CURL_SOCKET_BAD;
int wrotepidfile = 0;
const char *pidname = ".socksd.pid";
bool juggle_again;
int error;
int arg = 1;
while(argc>arg) {
if(!strcmp("--version", argv[arg])) {
printf("socksd IPv4%s\n",
#ifdef ENABLE_IPV6
"/IPv6"
#else
""
#endif
);
return 0;
}
else if(!strcmp("--pidfile", argv[arg])) {
arg++;
if(argc>arg)
pidname = argv[arg++];
}
else if(!strcmp("--config", argv[arg])) {
arg++;
if(argc>arg)
configfile = argv[arg++];
}
else if(!strcmp("--backend", argv[arg])) {
arg++;
if(argc>arg)
backendaddr = argv[arg++];
}
else if(!strcmp("--backendport", argv[arg])) {
arg++;
if(argc>arg)
backendport = (unsigned short)atoi(argv[arg++]);
}
else if(!strcmp("--logfile", argv[arg])) {
arg++;
if(argc>arg)
serverlogfile = argv[arg++];
}
else if(!strcmp("--ipv6", argv[arg])) {
#ifdef ENABLE_IPV6
ipv_inuse = "IPv6";
use_ipv6 = TRUE;
#endif
arg++;
}
else if(!strcmp("--ipv4", argv[arg])) {
/* for completeness, we support this option as well */
#ifdef ENABLE_IPV6
ipv_inuse = "IPv4";
use_ipv6 = FALSE;
#endif
arg++;
}
else if(!strcmp("--port", argv[arg])) {
arg++;
if(argc>arg) {
char *endptr;
unsigned long ulnum = strtoul(argv[arg], &endptr, 10);
if((endptr != argv[arg] + strlen(argv[arg])) ||
((ulnum != 0UL) && ((ulnum < 1025UL) || (ulnum > 65535UL)))) {
fprintf(stderr, "socksd: invalid --port argument (%s)\n",
argv[arg]);
return 0;
}
port = curlx_ultous(ulnum);
arg++;
}
}
else {
puts("Usage: socksd [option]\n"
" --backend [ipv4 addr]\n"
" --backendport [TCP port]\n"
" --config [file]\n"
" --version\n"
" --logfile [file]\n"
" --pidfile [file]\n"
" --ipv4\n"
" --ipv6\n"
" --bindonly\n"
" --port [port]\n");
return 0;
}
}
#ifdef WIN32
win32_init();
atexit(win32_cleanup);
setmode(fileno(stdin), O_BINARY);
setmode(fileno(stdout), O_BINARY);
setmode(fileno(stderr), O_BINARY);
#endif
install_signal_handlers();
#ifdef ENABLE_IPV6
if(!use_ipv6)
#endif
sock = socket(AF_INET, SOCK_STREAM, 0);
#ifdef ENABLE_IPV6
else
sock = socket(AF_INET6, SOCK_STREAM, 0);
#endif
if(CURL_SOCKET_BAD == sock) {
error = SOCKERRNO;
logmsg("Error creating socket: (%d) %s",
error, strerror(error));
goto socks5_cleanup;
}
{
/* passive daemon style */
sock = sockdaemon(sock, &port);
if(CURL_SOCKET_BAD == sock) {
goto socks5_cleanup;
}
msgsock = CURL_SOCKET_BAD; /* no stream socket yet */
}
logmsg("Running %s version", ipv_inuse);
logmsg("Listening on port %hu", port);
wrotepidfile = write_pidfile(pidname);
if(!wrotepidfile) {
goto socks5_cleanup;
}
do {
juggle_again = incoming(sock);
} while(juggle_again);
socks5_cleanup:
if((msgsock != sock) && (msgsock != CURL_SOCKET_BAD))
sclose(msgsock);
if(sock != CURL_SOCKET_BAD)
sclose(sock);
if(wrotepidfile)
unlink(pidname);
restore_signal_handlers();
if(got_exit_signal) {
logmsg("============> socksd exits with signal (%d)", exit_signal);
/*
* To properly set the return status of the process we
* must raise the same signal SIGINT or SIGTERM that we
* caught and let the old handler take care of it.
*/
raise(exit_signal);
}
logmsg("============> socksd quits");
return 0;
}
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