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socat/xio-socks.c

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/* source: xio-socks.c */
/* Copyright Gerhard Rieger */
/* Published under the GNU General Public License V.2, see file COPYING */
/* this file contains the source for opening addresses of socks4 type */
#include "xiosysincludes.h"
#if WITH_SOCKS4 || WITH_SOCKS4A
#include "xioopen.h"
#include "xio-ascii.h"
#include "xio-socket.h"
#include "xio-ip.h"
#include "xio-ipapp.h"
#include "xio-socks.h"
enum {
SOCKS_CD_GRANTED = 90,
SOCKS_CD_FAILED,
SOCKS_CD_NOIDENT,
SOCKS_CD_IDENTFAILED
} ;
#define SOCKSPORT "1080"
#define BUFF_LEN (SIZEOF_STRUCT_SOCKS4+512)
static int xioopen_socks4_connect(int argc, const char *argv[], struct opt *opts,
int xioflags, xiofile_t *fd,
unsigned groups, int dummy1, int dummy2,
int dummy3);
const struct optdesc opt_socksport = { "socksport", NULL, OPT_SOCKSPORT, GROUP_IP_SOCKS4, PH_LATE, TYPE_STRING, OFUNC_SPEC };
const struct optdesc opt_socksuser = { "socksuser", NULL, OPT_SOCKSUSER, GROUP_IP_SOCKS4, PH_LATE, TYPE_NAME, OFUNC_SPEC };
const struct addrdesc addr_socks4_connect = { "socks4", 3, xioopen_socks4_connect, GROUP_FD|GROUP_SOCKET|GROUP_SOCK_IP4|GROUP_SOCK_IP6|GROUP_IP_TCP|GROUP_IP_SOCKS4|GROUP_CHILD|GROUP_RETRY, 0, 0, 0 HELP(":<socks-server>:<host>:<port>") };
const struct addrdesc addr_socks4a_connect = { "socks4a", 3, xioopen_socks4_connect, GROUP_FD|GROUP_SOCKET|GROUP_SOCK_IP4|GROUP_SOCK_IP6|GROUP_IP_TCP|GROUP_IP_SOCKS4|GROUP_CHILD|GROUP_RETRY, 1, 0, 0 HELP(":<socks-server>:<host>:<port>") };
static int xioopen_socks4_connect(int argc, const char *argv[], struct opt *opts,
int xioflags, xiofile_t *xxfd,
unsigned groups, int socks4a, int dummy2,
int dummy3) {
/* we expect the form: host:host:port */
struct single *xfd = &xxfd->stream;
struct opt *opts0 = NULL;
const char *sockdname; char *socksport;
const char *targetname, *targetport;
int pf = PF_UNSPEC;
int ipproto = IPPROTO_TCP;
bool dofork = false;
union sockaddr_union us_sa, *us = &us_sa;
union sockaddr_union them_sa, *them = &them_sa;
socklen_t uslen = sizeof(us_sa);
socklen_t themlen = sizeof(them_sa);
bool needbind = false;
bool lowport = false;
unsigned char buff[BUFF_LEN];
struct socks4 *sockhead = (struct socks4 *)buff;
size_t buflen = sizeof(buff);
int socktype = SOCK_STREAM;
int level;
int result;
if (argc != 4) {
Error1("%s: 3 parameters required", argv[0]);
return STAT_NORETRY;
}
sockdname = argv[1];
targetname = argv[2];
targetport = argv[3];
xfd->howtoend = END_SHUTDOWN;
if (applyopts_single(xfd, opts, PH_INIT) < 0) return -1;
applyopts(-1, opts, PH_INIT);
retropt_int(opts, OPT_SO_TYPE, &socktype);
retropt_bool(opts, OPT_FORK, &dofork);
result = _xioopen_socks4_prepare(targetport, opts, &socksport, sockhead, &buflen);
if (result != STAT_OK) return result;
result =
_xioopen_ipapp_prepare(opts, &opts0, sockdname, socksport,
&pf, ipproto,
xfd->para.socket.ip.res_opts[1],
xfd->para.socket.ip.res_opts[0],
them, &themlen, us, &uslen,
&needbind, &lowport, socktype);
Notice5("opening connection to %s:%u via socks4 server %s:%s as user \"%s\"",
targetname,
ntohs(sockhead->port),
sockdname, socksport, sockhead->userid);
do { /* loop over failed connect and socks-request attempts */
#if WITH_RETRY
if (xfd->forever || xfd->retry) {
level = E_INFO;
} else
#endif /* WITH_RETRY */
level = E_ERROR;
/* we try to resolve the target address _before_ connecting to the socks
server: this avoids unnecessary socks connects and timeouts */
result =
_xioopen_socks4_connect0(xfd, targetname, socks4a, sockhead,
(ssize_t *)&buflen, level);
switch (result) {
case STAT_OK: break;
#if WITH_RETRY
case STAT_RETRYLATER:
case STAT_RETRYNOW:
if (xfd->forever || xfd->retry--) {
if (result == STAT_RETRYLATER) Nanosleep(&xfd->intervall, NULL);
continue;
}
#endif /* WITH_RETRY */
default:
return result;
}
/* this cannot fork because we retrieved fork option above */
result =
_xioopen_connect (xfd,
needbind?(struct sockaddr *)us:NULL, sizeof(*us),
(struct sockaddr *)them, themlen,
opts, pf, socktype, IPPROTO_TCP, lowport, level);
switch (result) {
case STAT_OK: break;
#if WITH_RETRY
case STAT_RETRYLATER:
case STAT_RETRYNOW:
if (xfd->forever || xfd->retry--) {
if (result == STAT_RETRYLATER) Nanosleep(&xfd->intervall, NULL);
continue;
}
#endif /* WITH_RETRY */
default:
return result;
}
applyopts(xfd->fd, opts, PH_ALL);
if ((result = _xio_openlate(xfd, opts)) < 0)
return result;
result = _xioopen_socks4_connect(xfd, sockhead, buflen, level);
switch (result) {
case STAT_OK: break;
#if WITH_RETRY
case STAT_RETRYLATER:
case STAT_RETRYNOW:
if (xfd->forever || xfd->retry--) {
if (result == STAT_RETRYLATER) Nanosleep(&xfd->intervall, NULL);
continue;
}
#endif /* WITH_RETRY */
default:
return result;
}
if (dofork) {
xiosetchilddied(); /* set SIGCHLD handler */
}
#if WITH_RETRY
if (dofork) {
pid_t pid;
int level = E_ERROR;
if (xfd->forever || xfd->retry) {
level = E_WARN; /* most users won't expect a problem here,
so Notice is too weak */
}
while ((pid = xio_fork(false, level)) < 0) {
if (xfd->forever || --xfd->retry) {
Nanosleep(&xfd->intervall, NULL);
continue;
}
return STAT_RETRYLATER;
}
if (pid == 0) { /* child process */
xfd->forever = false; xfd->retry = 0;
break;
}
/* parent process */
Close(xfd->fd);
Nanosleep(&xfd->intervall, NULL);
dropopts(opts, PH_ALL); opts = copyopts(opts0, GROUP_ALL);
continue;
} else
#endif /* WITH_RETRY */
{
break;
}
} while (true); /* end of complete open loop - drop out on success */
return 0;
}
int _xioopen_socks4_prepare(const char *targetport, struct opt *opts, char **socksport, struct socks4 *sockhead, size_t *headlen) {
struct servent *se;
char *userid;
/* generate socks header - points to final target */
sockhead->version = 4;
sockhead->action = 1;
sockhead->port = parseport(targetport, IPPROTO_TCP); /* network byte
order */
if (retropt_string(opts, OPT_SOCKSPORT, socksport) < 0) {
if ((se = getservbyname("socks", "tcp")) != NULL) {
Debug1("\"socks/tcp\" resolves to %u", ntohs(se->s_port));
if ((*socksport = Malloc(6)) == NULL) {
return -1;
}
sprintf(*socksport, "%u", ntohs(se->s_port));
} else {
Debug1("cannot resolve service \"socks/tcp\", using %s", SOCKSPORT);
if ((*socksport = strdup(SOCKSPORT)) == NULL) {
errno = ENOMEM; return -1;
}
}
}
if (retropt_string(opts, OPT_SOCKSUSER, &userid) < 0) {
if ((userid = getenv("LOGNAME")) == NULL) {
if ((userid = getenv("USER")) == NULL) {
userid = "anonymous";
}
}
}
sockhead->userid[0] = '\0'; strncat(sockhead->userid, userid, *headlen-SIZEOF_STRUCT_SOCKS4-1);
*headlen = SIZEOF_STRUCT_SOCKS4+strlen(userid)+1;
return STAT_OK;
}
/* called within retry/fork loop, before connect() */
int
_xioopen_socks4_connect0(struct single *xfd,
const char *hostname, /* socks target host */
int socks4a,
struct socks4 *sockhead,
ssize_t *headlen, /* get available space,
return used length*/
int level) {
int result;
if (!socks4a) {
union sockaddr_union sau;
socklen_t saulen = sizeof(sau);
if ((result = xiogetaddrinfo(hostname, NULL,
PF_INET, SOCK_STREAM, IPPROTO_TCP,
&sau, &saulen,
xfd->para.socket.ip.res_opts[1],
xfd->para.socket.ip.res_opts[0]))
!= STAT_OK) {
return result; /*! STAT_RETRY? */
}
memcpy(&sockhead->dest, &sau.ip4.sin_addr, 4);
}
#if WITH_SOCKS4A
else {
/*! noresolve */
sockhead->dest = htonl(0x00000001); /* three bytes zero */
}
#endif /* WITH_SOCKS4A */
#if WITH_SOCKS4A
if (socks4a) {
/* SOCKS4A requires us to append the host name to resolve
after the user name's trailing 0 byte. */
char* insert_position = (char*) sockhead + *headlen;
insert_position[0] = '\0'; strncat(insert_position, hostname, BUFF_LEN-*headlen-1);
((char *)sockhead)[BUFF_LEN-1] = 0;
*headlen += strlen(hostname) + 1;
if (*headlen > BUFF_LEN) {
*headlen = BUFF_LEN;
}
}
#endif /* WITH_SOCKS4A */
return STAT_OK;
}
/* perform socks4 client dialog on existing FD.
Called within fork/retry loop, after connect() */
int _xioopen_socks4_connect(struct single *xfd,
struct socks4 *sockhead,
size_t headlen,
int level) {
ssize_t bytes;
int result;
unsigned char buff[SIZEOF_STRUCT_SOCKS4];
struct socks4 *replyhead = (struct socks4 *)buff;
char *destdomname = NULL;
/* send socks header (target addr+port, +auth) */
#if WITH_MSGLEVEL <= E_INFO
if (ntohl(sockhead->dest) <= 0x000000ff) {
destdomname = strchr(sockhead->userid, '\0')+1;
}
Info11("sending socks4%s request VN=%d DC=%d DSTPORT=%d DSTIP=%d.%d.%d.%d USERID=%s%s%s",
destdomname?"a":"",
sockhead->version, sockhead->action, ntohs(sockhead->port),
((unsigned char *)&sockhead->dest)[0],
((unsigned char *)&sockhead->dest)[1],
((unsigned char *)&sockhead->dest)[2],
((unsigned char *)&sockhead->dest)[3],
sockhead->userid,
destdomname?" DESTNAME=":"",
destdomname?destdomname:"");
#endif /* WITH_MSGLEVEL <= E_INFO */
#if WITH_MSGLEVEL <= E_DEBUG
{
char *msgbuff;
if ((msgbuff = Malloc(3*headlen)) != NULL) {
xiohexdump((const unsigned char *)sockhead, headlen, msgbuff);
Debug1("sending socks4(a) request data %s", msgbuff);
}
}
#endif /* WITH_MSGLEVEL <= E_DEBUG */
if (writefull(xfd->fd, sockhead, headlen) < 0) {
Msg4(level, "write(%d, %p, "F_Zu"): %s",
xfd->fd, sockhead, headlen, strerror(errno));
if (Close(xfd->fd) < 0) {
Info2("close(%d): %s", xfd->fd, strerror(errno));
}
return STAT_RETRYLATER; /* retry complete open cycle */
}
bytes = 0;
Info("waiting for socks reply");
while (bytes >= 0) { /* loop over answer chunks until complete or error */
/* receive socks answer */
do {
result = Read(xfd->fd, buff+bytes, SIZEOF_STRUCT_SOCKS4-bytes);
} while (result < 0 && errno == EINTR);
if (result < 0) {
Msg4(level, "read(%d, %p, "F_Zu"): %s",
xfd->fd, buff+bytes, SIZEOF_STRUCT_SOCKS4-bytes,
strerror(errno));
if (Close(xfd->fd) < 0) {
Info2("close(%d): %s", xfd->fd, strerror(errno));
}
}
if (result == 0) {
Msg(level, "read(): EOF during read of socks reply, peer might not be a socks4 server");
if (Close(xfd->fd) < 0) {
Info2("close(%d): %s", xfd->fd, strerror(errno));
}
return STAT_RETRYLATER;
}
#if WITH_MSGLEVEL <= E_DEBUG
{
char msgbuff[3*SIZEOF_STRUCT_SOCKS4];
* xiohexdump((const unsigned char *)replyhead+bytes, result, msgbuff)
= '\0';
Debug2("received socks4 reply data (offset "F_Zd"): %s", bytes, msgbuff);
}
#endif /* WITH_MSGLEVEL <= E_DEBUG */
bytes += result;
if (bytes == SIZEOF_STRUCT_SOCKS4) {
Debug1("received all "F_Zd" bytes", bytes);
break;
}
Debug2("received %d bytes, waiting for "F_Zu" more bytes",
result, SIZEOF_STRUCT_SOCKS4-bytes);
}
if (result <= 0) { /* we had a problem while reading socks answer */
return STAT_RETRYLATER; /* retry complete open cycle */
}
Info7("received socks reply VN=%u CD=%u DSTPORT=%u DSTIP=%u.%u.%u.%u",
replyhead->version, replyhead->action, ntohs(replyhead->port),
((uint8_t *)&replyhead->dest)[0],
((uint8_t *)&replyhead->dest)[1],
((uint8_t *)&replyhead->dest)[2],
((uint8_t *)&replyhead->dest)[3]);
if (replyhead->version != 0) {
Warn1("socks: reply code version is not 0 (%d)",
replyhead->version);
}
switch (replyhead->action) {
case SOCKS_CD_GRANTED:
/* Notice("socks: connect request succeeded"); */
#if 0
if (Getsockname(xfd->fd, (struct sockaddr *)&us, &uslen) < 0) {
Warn4("getsockname(%d, %p, {%d}): %s",
xfd->fd, &us, uslen, strerror(errno));
}
Notice1("successfully connected from %s via socks4",
sockaddr_info((struct sockaddr *)&us, infobuff, sizeof(infobuff)));
#else
Notice("successfully connected via socks4");
#endif
break;
case SOCKS_CD_FAILED:
Msg(level, "socks: connect request rejected or failed");
return STAT_RETRYLATER;
case SOCKS_CD_NOIDENT:
Msg(level, "socks: ident refused by client");
return STAT_RETRYLATER;
case SOCKS_CD_IDENTFAILED:
Msg(level, "socks: ident failed");
return STAT_RETRYLATER;
default:
Msg1(level, "socks: undefined status %u", replyhead->action);
}
return STAT_OK;
}
#endif /* WITH_SOCKS4 || WITH_SOCKS4A */
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