mirror of
https://github.com/moparisthebest/socat
synced 2024-12-21 22:48:48 -05:00
428 lines
13 KiB
C
428 lines
13 KiB
C
/* source: xio-socks.c */
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/* Copyright Gerhard Rieger */
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/* Published under the GNU General Public License V.2, see file COPYING */
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/* this file contains the source for opening addresses of socks4 type */
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#include "xiosysincludes.h"
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#if WITH_SOCKS4 || WITH_SOCKS4A
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#include "xioopen.h"
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#include "xio-ascii.h"
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#include "xio-socket.h"
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#include "xio-ip.h"
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#include "xio-ipapp.h"
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#include "xio-socks.h"
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enum {
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SOCKS_CD_GRANTED = 90,
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SOCKS_CD_FAILED,
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SOCKS_CD_NOIDENT,
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SOCKS_CD_IDENTFAILED
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} ;
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#define SOCKSPORT "1080"
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#define BUFF_LEN (SIZEOF_STRUCT_SOCKS4+512)
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static int xioopen_socks4_connect(int argc, const char *argv[], struct opt *opts,
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int xioflags, xiofile_t *fd,
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unsigned groups, int dummy1, int dummy2,
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int dummy3);
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const struct optdesc opt_socksport = { "socksport", NULL, OPT_SOCKSPORT, GROUP_IP_SOCKS4, PH_LATE, TYPE_STRING, OFUNC_SPEC };
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const struct optdesc opt_socksuser = { "socksuser", NULL, OPT_SOCKSUSER, GROUP_IP_SOCKS4, PH_LATE, TYPE_NAME, OFUNC_SPEC };
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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>") };
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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>") };
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static int xioopen_socks4_connect(int argc, const char *argv[], struct opt *opts,
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int xioflags, xiofile_t *xxfd,
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unsigned groups, int socks4a, int dummy2,
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int dummy3) {
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/* we expect the form: host:host:port */
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struct single *xfd = &xxfd->stream;
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struct opt *opts0 = NULL;
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const char *sockdname; char *socksport;
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const char *targetname, *targetport;
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int pf = PF_UNSPEC;
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int ipproto = IPPROTO_TCP;
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bool dofork = false;
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union sockaddr_union us_sa, *us = &us_sa;
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union sockaddr_union them_sa, *them = &them_sa;
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socklen_t uslen = sizeof(us_sa);
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socklen_t themlen = sizeof(them_sa);
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bool needbind = false;
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bool lowport = false;
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unsigned char buff[BUFF_LEN];
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struct socks4 *sockhead = (struct socks4 *)buff;
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size_t buflen = sizeof(buff);
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int socktype = SOCK_STREAM;
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int level;
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int result;
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if (argc != 4) {
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Error1("%s: 3 parameters required", argv[0]);
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return STAT_NORETRY;
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}
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sockdname = argv[1];
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targetname = argv[2];
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targetport = argv[3];
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xfd->howtoend = END_SHUTDOWN;
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if (applyopts_single(xfd, opts, PH_INIT) < 0) return -1;
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applyopts(-1, opts, PH_INIT);
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retropt_int(opts, OPT_SO_TYPE, &socktype);
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retropt_bool(opts, OPT_FORK, &dofork);
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result = _xioopen_socks4_prepare(targetport, opts, &socksport, sockhead, &buflen);
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if (result != STAT_OK) return result;
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result =
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_xioopen_ipapp_prepare(opts, &opts0, sockdname, socksport,
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&pf, ipproto,
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xfd->para.socket.ip.res_opts[1],
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xfd->para.socket.ip.res_opts[0],
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them, &themlen, us, &uslen,
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&needbind, &lowport, socktype);
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Notice5("opening connection to %s:%u via socks4 server %s:%s as user \"%s\"",
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targetname,
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ntohs(sockhead->port),
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sockdname, socksport, sockhead->userid);
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do { /* loop over failed connect and socks-request attempts */
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#if WITH_RETRY
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if (xfd->forever || xfd->retry) {
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level = E_INFO;
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} else
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#endif /* WITH_RETRY */
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level = E_ERROR;
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/* we try to resolve the target address _before_ connecting to the socks
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server: this avoids unnecessary socks connects and timeouts */
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result =
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_xioopen_socks4_connect0(xfd, targetname, socks4a, sockhead,
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(ssize_t *)&buflen, level);
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switch (result) {
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case STAT_OK: break;
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#if WITH_RETRY
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case STAT_RETRYLATER:
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case STAT_RETRYNOW:
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if (xfd->forever || xfd->retry--) {
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if (result == STAT_RETRYLATER) Nanosleep(&xfd->intervall, NULL);
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continue;
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}
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#endif /* WITH_RETRY */
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default:
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return result;
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}
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/* this cannot fork because we retrieved fork option above */
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result =
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_xioopen_connect (xfd,
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needbind?(struct sockaddr *)us:NULL, sizeof(*us),
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(struct sockaddr *)them, themlen,
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opts, pf, socktype, IPPROTO_TCP, lowport, level);
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switch (result) {
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case STAT_OK: break;
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#if WITH_RETRY
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case STAT_RETRYLATER:
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case STAT_RETRYNOW:
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if (xfd->forever || xfd->retry--) {
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if (result == STAT_RETRYLATER) Nanosleep(&xfd->intervall, NULL);
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continue;
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}
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#endif /* WITH_RETRY */
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default:
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return result;
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}
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applyopts(xfd->fd, opts, PH_ALL);
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if ((result = _xio_openlate(xfd, opts)) < 0)
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return result;
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result = _xioopen_socks4_connect(xfd, sockhead, buflen, level);
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switch (result) {
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case STAT_OK: break;
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#if WITH_RETRY
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case STAT_RETRYLATER:
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case STAT_RETRYNOW:
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if (xfd->forever || xfd->retry--) {
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if (result == STAT_RETRYLATER) Nanosleep(&xfd->intervall, NULL);
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continue;
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}
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#endif /* WITH_RETRY */
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default:
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return result;
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}
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if (dofork) {
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xiosetchilddied(); /* set SIGCHLD handler */
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}
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#if WITH_RETRY
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if (dofork) {
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pid_t pid;
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int level = E_ERROR;
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if (xfd->forever || xfd->retry) {
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level = E_WARN; /* most users won't expect a problem here,
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so Notice is too weak */
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}
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while ((pid = xio_fork(false, level)) < 0) {
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if (xfd->forever || --xfd->retry) {
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Nanosleep(&xfd->intervall, NULL);
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continue;
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}
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return STAT_RETRYLATER;
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}
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if (pid == 0) { /* child process */
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xfd->forever = false; xfd->retry = 0;
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break;
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}
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/* parent process */
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Close(xfd->fd);
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Nanosleep(&xfd->intervall, NULL);
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dropopts(opts, PH_ALL); opts = copyopts(opts0, GROUP_ALL);
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continue;
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} else
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#endif /* WITH_RETRY */
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{
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break;
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}
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} while (true); /* end of complete open loop - drop out on success */
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return 0;
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}
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int _xioopen_socks4_prepare(const char *targetport, struct opt *opts, char **socksport, struct socks4 *sockhead, size_t *headlen) {
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struct servent *se;
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char *userid;
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/* generate socks header - points to final target */
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sockhead->version = 4;
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sockhead->action = 1;
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sockhead->port = parseport(targetport, IPPROTO_TCP); /* network byte
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order */
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if (retropt_string(opts, OPT_SOCKSPORT, socksport) < 0) {
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if ((se = getservbyname("socks", "tcp")) != NULL) {
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Debug1("\"socks/tcp\" resolves to %u", ntohs(se->s_port));
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if ((*socksport = Malloc(6)) == NULL) {
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return -1;
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}
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sprintf(*socksport, "%u", ntohs(se->s_port));
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} else {
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Debug1("cannot resolve service \"socks/tcp\", using %s", SOCKSPORT);
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if ((*socksport = strdup(SOCKSPORT)) == NULL) {
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errno = ENOMEM; return -1;
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}
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}
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}
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if (retropt_string(opts, OPT_SOCKSUSER, &userid) < 0) {
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if ((userid = getenv("LOGNAME")) == NULL) {
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if ((userid = getenv("USER")) == NULL) {
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userid = "anonymous";
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}
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}
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}
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sockhead->userid[0] = '\0'; strncat(sockhead->userid, userid, *headlen-SIZEOF_STRUCT_SOCKS4-1);
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*headlen = SIZEOF_STRUCT_SOCKS4+strlen(userid)+1;
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return STAT_OK;
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}
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/* called within retry/fork loop, before connect() */
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int
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_xioopen_socks4_connect0(struct single *xfd,
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const char *hostname, /* socks target host */
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int socks4a,
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struct socks4 *sockhead,
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ssize_t *headlen, /* get available space,
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return used length*/
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int level) {
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int result;
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if (!socks4a) {
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union sockaddr_union sau;
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socklen_t saulen = sizeof(sau);
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if ((result = xiogetaddrinfo(hostname, NULL,
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PF_INET, SOCK_STREAM, IPPROTO_TCP,
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&sau, &saulen,
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xfd->para.socket.ip.res_opts[1],
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xfd->para.socket.ip.res_opts[0]))
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!= STAT_OK) {
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return result; /*! STAT_RETRY? */
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}
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memcpy(&sockhead->dest, &sau.ip4.sin_addr, 4);
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}
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#if WITH_SOCKS4A
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else {
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/*! noresolve */
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sockhead->dest = htonl(0x00000001); /* three bytes zero */
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}
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#endif /* WITH_SOCKS4A */
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#if WITH_SOCKS4A
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if (socks4a) {
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/* SOCKS4A requires us to append the host name to resolve
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after the user name's trailing 0 byte. */
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char* insert_position = (char*) sockhead + *headlen;
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insert_position[0] = '\0'; strncat(insert_position, hostname, BUFF_LEN-*headlen-1);
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((char *)sockhead)[BUFF_LEN-1] = 0;
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*headlen += strlen(hostname) + 1;
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if (*headlen > BUFF_LEN) {
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*headlen = BUFF_LEN;
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}
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}
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#endif /* WITH_SOCKS4A */
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return STAT_OK;
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}
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/* perform socks4 client dialog on existing FD.
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Called within fork/retry loop, after connect() */
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int _xioopen_socks4_connect(struct single *xfd,
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struct socks4 *sockhead,
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size_t headlen,
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int level) {
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ssize_t bytes;
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int result;
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unsigned char buff[SIZEOF_STRUCT_SOCKS4];
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struct socks4 *replyhead = (struct socks4 *)buff;
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char *destdomname = NULL;
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/* send socks header (target addr+port, +auth) */
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#if WITH_MSGLEVEL <= E_INFO
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if (ntohl(sockhead->dest) <= 0x000000ff) {
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destdomname = strchr(sockhead->userid, '\0')+1;
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}
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Info11("sending socks4%s request VN=%d DC=%d DSTPORT=%d DSTIP=%d.%d.%d.%d USERID=%s%s%s",
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destdomname?"a":"",
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sockhead->version, sockhead->action, ntohs(sockhead->port),
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((unsigned char *)&sockhead->dest)[0],
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((unsigned char *)&sockhead->dest)[1],
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((unsigned char *)&sockhead->dest)[2],
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((unsigned char *)&sockhead->dest)[3],
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sockhead->userid,
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destdomname?" DESTNAME=":"",
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destdomname?destdomname:"");
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#endif /* WITH_MSGLEVEL <= E_INFO */
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#if WITH_MSGLEVEL <= E_DEBUG
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{
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char *msgbuff;
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if ((msgbuff = Malloc(3*headlen)) != NULL) {
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xiohexdump((const unsigned char *)sockhead, headlen, msgbuff);
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Debug1("sending socks4(a) request data %s", msgbuff);
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}
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}
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#endif /* WITH_MSGLEVEL <= E_DEBUG */
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if (writefull(xfd->fd, sockhead, headlen) < 0) {
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Msg4(level, "write(%d, %p, "F_Zu"): %s",
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xfd->fd, sockhead, headlen, strerror(errno));
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if (Close(xfd->fd) < 0) {
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Info2("close(%d): %s", xfd->fd, strerror(errno));
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}
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return STAT_RETRYLATER; /* retry complete open cycle */
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}
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bytes = 0;
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Info("waiting for socks reply");
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while (bytes >= 0) { /* loop over answer chunks until complete or error */
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/* receive socks answer */
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do {
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result = Read(xfd->fd, buff+bytes, SIZEOF_STRUCT_SOCKS4-bytes);
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} while (result < 0 && errno == EINTR);
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if (result < 0) {
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Msg4(level, "read(%d, %p, "F_Zu"): %s",
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xfd->fd, buff+bytes, SIZEOF_STRUCT_SOCKS4-bytes,
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strerror(errno));
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if (Close(xfd->fd) < 0) {
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Info2("close(%d): %s", xfd->fd, strerror(errno));
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}
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}
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if (result == 0) {
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Msg(level, "read(): EOF during read of socks reply, peer might not be a socks4 server");
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if (Close(xfd->fd) < 0) {
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Info2("close(%d): %s", xfd->fd, strerror(errno));
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}
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return STAT_RETRYLATER;
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}
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#if WITH_MSGLEVEL <= E_DEBUG
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{
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char msgbuff[3*SIZEOF_STRUCT_SOCKS4];
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* xiohexdump((const unsigned char *)replyhead+bytes, result, msgbuff)
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= '\0';
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Debug2("received socks4 reply data (offset "F_Zd"): %s", bytes, msgbuff);
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}
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#endif /* WITH_MSGLEVEL <= E_DEBUG */
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bytes += result;
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if (bytes == SIZEOF_STRUCT_SOCKS4) {
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Debug1("received all "F_Zd" bytes", bytes);
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break;
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}
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Debug2("received %d bytes, waiting for "F_Zu" more bytes",
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result, SIZEOF_STRUCT_SOCKS4-bytes);
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}
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if (result <= 0) { /* we had a problem while reading socks answer */
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return STAT_RETRYLATER; /* retry complete open cycle */
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}
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Info7("received socks reply VN=%u CD=%u DSTPORT=%u DSTIP=%u.%u.%u.%u",
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replyhead->version, replyhead->action, ntohs(replyhead->port),
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((uint8_t *)&replyhead->dest)[0],
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((uint8_t *)&replyhead->dest)[1],
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((uint8_t *)&replyhead->dest)[2],
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((uint8_t *)&replyhead->dest)[3]);
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if (replyhead->version != 0) {
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Warn1("socks: reply code version is not 0 (%d)",
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replyhead->version);
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}
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switch (replyhead->action) {
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case SOCKS_CD_GRANTED:
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/* Notice("socks: connect request succeeded"); */
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#if 0
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if (Getsockname(xfd->fd, (struct sockaddr *)&us, &uslen) < 0) {
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Warn4("getsockname(%d, %p, {%d}): %s",
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xfd->fd, &us, uslen, strerror(errno));
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}
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Notice1("successfully connected from %s via socks4",
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sockaddr_info((struct sockaddr *)&us, infobuff, sizeof(infobuff)));
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#else
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Notice("successfully connected via socks4");
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#endif
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break;
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case SOCKS_CD_FAILED:
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Msg(level, "socks: connect request rejected or failed");
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return STAT_RETRYLATER;
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case SOCKS_CD_NOIDENT:
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Msg(level, "socks: ident refused by client");
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return STAT_RETRYLATER;
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case SOCKS_CD_IDENTFAILED:
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Msg(level, "socks: ident failed");
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return STAT_RETRYLATER;
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default:
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Msg1(level, "socks: undefined status %u", replyhead->action);
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}
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return STAT_OK;
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}
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#endif /* WITH_SOCKS4 || WITH_SOCKS4A */
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