socat-2_6bfd3dd22c9f930f9a2eab223f929bde1c786fdf-REDIRECT.patch

From c0902814a932bc987c56685801fe5a5c81861412 Mon Sep 17 00:00:00 2001
From: Vitaly _Vi Shukela <public_vi@tut.by>
Date: Thu, 25 Mar 2010 17:10:31 +0200
Subject: [PATCH 1/4] Add .gitignore

---
 .gitignore |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..f9401f1
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,14 @@
+*.o
+/filan
+/socat
+/procan
+*.a
+doc/socat.1
+doc/socat.html
+/configure
+config.h
+config.status
+config.log
+autom4te.cache
+Makefile
+.*.swp
-- 
1.7.0.3


From 2bb40eec45365cd5955187b7569b0a5bac07d0d8 Mon Sep 17 00:00:00 2001
From: Vitaly _Vi Shukela <public_vi@tut.by>
Date: Thu, 25 Mar 2010 17:34:47 +0200
Subject: [PATCH 2/4] Retrieve and save non-REDIRECT-ed destination address and port in listening sockets.

---
 xio-listen.c |   23 +++++++++++++++++++++++
 xioopen.h    |    2 ++
 2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/xio-listen.c b/xio-listen.c
index 2358d78..1ea2d3f 100644
--- a/xio-listen.c
+++ b/xio-listen.c
@@ -24,6 +24,8 @@ const struct optdesc opt_fork    = { "fork",      NULL, OPT_FORK,        GROUP_C
 const struct optdesc opt_range   = { "range",     NULL, OPT_RANGE,       GROUP_RANGE,  PH_ACCEPT, TYPE_STRING, OFUNC_SPEC };
 #endif
 
+char redirect_hostname[255]; /* retreived host IP address for REDIRECT mode. Accessed from other places. */
+char redirect_port[32]; /* retrieved port number for REDIRECT mode. Accessed from other places. */
 
 /*
    applies and consumes the following option:
@@ -119,10 +121,13 @@ int _xioopen_listen(struct single *xfd, int xioflags, struct sockaddr *us, sockl
    char lisname[256];
    union sockaddr_union _peername;
    union sockaddr_union _sockname;
+   union sockaddr_union _destname;
    union sockaddr_union *pa = &_peername;	/* peer address */
    union sockaddr_union *la = &_sockname;	/* local address */
+   union sockaddr_union *da = &_destname;	/* destination address (before REDIRECT)*/
    socklen_t pas = sizeof(_peername);	/* peer address size */
    socklen_t las = sizeof(_sockname);	/* local address size */
+   socklen_t das = sizeof(_destname);	/* destination address size */
    int result;
 
    retropt_bool(opts, OPT_FORK, &dofork);
@@ -225,6 +230,7 @@ int _xioopen_listen(struct single *xfd, int xioflags, struct sockaddr *us, sockl
    while (true) {	/* but we only loop if fork option is set */
       char peername[256];
       char sockname[256];
+      char destname[256];
       int ps;		/* peer socket */
       salen = sizeof(struct sockaddr);
 
@@ -260,11 +266,27 @@ int _xioopen_listen(struct single *xfd, int xioflags, struct sockaddr *us, sockl
 	       ps, la, las, strerror(errno));
 	 la = NULL;
       }
+       #ifndef SO_ORIGINAL_DST
+	#define SO_ORIGINAL_DST 80
+       #endif
+      if (Getsockopt(ps, SOL_IP, SO_ORIGINAL_DST, &da->soa, &das) != 0) {
+	 Warn4("getsockopt(%d, %p, {"F_socklen"}): %s",
+	       ps, da, das, strerror(errno));
+	 da = NULL;
+      } 
+
+      strncpy(redirect_hostname,inet_ntoa(_destname.ip4.sin_addr),256);
+      sprintf(redirect_port,"%d", ntohs(_destname.ip4.sin_port));
+
       Notice2("accepting connection from %s on %s",
 	      pa?
 	      sockaddr_info(&pa->soa, pas, peername, sizeof(peername)):"NULL",
 	      la?
 	      sockaddr_info(&la->soa, las, sockname, sizeof(sockname)):"NULL");
+      if(memcmp(&la->soa,&da->soa,sizeof(da->soa))) {
+         Notice1("actual non-REDIRECT-ed destination is %s",
+	      da?sockaddr_info(&da->soa, das, destname, sizeof(destname)):"NULL");
+      }
 
       if (pa != NULL && la != NULL && xiocheckpeer(xfd, pa, la) < 0) {
 	 if (Shutdown(ps, 2) < 0) {
@@ -336,6 +358,7 @@ int _xioopen_listen(struct single *xfd, int xioflags, struct sockaddr *us, sockl
    /* set the env vars describing the local and remote sockets */
    if (la != NULL)  xiosetsockaddrenv("SOCK", la, las, proto);
    if (pa != NULL)  xiosetsockaddrenv("PEER", pa, pas, proto);
+   if (da != NULL)  xiosetsockaddrenv("DEST", da, das, proto);
 
    return 0;
 }
diff --git a/xioopen.h b/xioopen.h
index 8984ebc..a7e2fb5 100644
--- a/xioopen.h
+++ b/xioopen.h
@@ -99,5 +99,7 @@ extern int xioopen_makedual(xiofile_t *file);
 #  define retropt_gidt(x,y,z) retropt_ulong(x,y,z)
 #endif
 
+extern char redirect_hostname[255]; /* retreived host IP address for REDIRECT mode. */
+extern char redirect_port[32]; /* retrieved port number for REDIRECT mode. */
 
 #endif /* !defined(__xioopen_h_included) */
-- 
1.7.0.3


From a5d5a3643865037f6d76fa4bf9412ee2df96fcfa Mon Sep 17 00:00:00 2001
From: Vitaly _Vi Shukela <public_vi@tut.by>
Date: Thu, 25 Mar 2010 17:34:07 +0200
Subject: [PATCH 3/4] REDIRECT target address and port for ip, proxy, socks and socks5

---
 xio-ip.c     |   11 +++++++++++
 xio-proxy.c  |    7 +++++++
 xio-socks.c  |    8 ++++++++
 xio-socks5.c |    8 ++++++++
 4 files changed, 34 insertions(+), 0 deletions(-)

diff --git a/xio-ip.c b/xio-ip.c
index 365f066..4574f01 100644
--- a/xio-ip.c
+++ b/xio-ip.c
@@ -111,6 +111,7 @@ unsigned long res_opts() {
    [::2]   (IPv6 address)
    hostname (hostname resolving to IPv4 or IPv6 address)
    hostname.domain (fq hostname resolving to IPv4 or IPv6 address)
+   "REDIRECT" (IPv4 address) - get redirected address from listening socket
  service: the port specification; may be numeric or symbolic
  family: PF_INET, PF_INET6, or PF_UNSPEC permitting both
  socktype: SOCK_STREAM, SOCK_DGRAM
@@ -161,6 +162,15 @@ int xiogetaddrinfo(const char *node, const char *service,
       service = NULL; 
    }
 
+   if (service && !strcmp(service,"REDIRECT")) {
+      port=atoi(redirect_port);
+      service=NULL;
+   }
+
+   if (node && !strcmp(node,"REDIRECT")) {
+      node=redirect_hostname;
+   }
+
    /* the resolver functions might handle numeric forms of node names by
       reverse lookup, that's not what we want.
       So we detect these and handle them specially */
@@ -209,6 +219,7 @@ int xiogetaddrinfo(const char *node, const char *service,
 #endif /* WITH_IP6 */
    }
 
+
 #if HAVE_GETADDRINFO
    if (node != NULL || service != NULL) {
       struct addrinfo *record;
diff --git a/xio-proxy.c b/xio-proxy.c
index 4e67fe2..198a1cc 100644
--- a/xio-proxy.c
+++ b/xio-proxy.c
@@ -103,6 +103,13 @@ static int xioopen_proxy_connect2(int argc, const char *argv[], struct opt *opts
       }
       targetname = argv[1];
       targetport = argv[2];
+   
+   if(!strcasecmp(targetname,"REDIRECT")) {
+       targetname=redirect_hostname;
+   }
+   if(!strcasecmp(targetport,"REDIRECT")) {
+       targetport=redirect_port;
+   }
 
    if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;
    applyopts(-1, opts, PH_INIT);
diff --git a/xio-socks.c b/xio-socks.c
index f8961a2..fc82526 100644
--- a/xio-socks.c
+++ b/xio-socks.c
@@ -104,6 +104,14 @@ static int xioopen_socks4_connect(int argc, const char *argv[], struct opt *opts
       targetport = argv[3];
    }
 
+   if(!strcasecmp(targetname,"REDIRECT")) {
+       targetname=redirect_hostname;
+   }
+   if(!strcasecmp(targetport,"REDIRECT")) {
+       targetport=redirect_port;
+   }
+
+
    if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;
    applyopts(-1, opts, PH_INIT);
 
diff --git a/xio-socks5.c b/xio-socks5.c
index 7c08862..2990947 100644
--- a/xio-socks5.c
+++ b/xio-socks5.c
@@ -88,6 +88,7 @@ static int xioopen_socks5_client(int argc, const char *argv[],
    /* we expect the form: host:port */
    xiosingle_t *xfd = &xxfd->stream;
    const char *targetname, *targetservice;
+   char targetname_[256]; char targetservice_[16];
    int level;
    int result;
 
@@ -112,6 +113,13 @@ static int xioopen_socks5_client(int argc, const char *argv[],
       return -1;
    }
 
+   if(!strcasecmp(targetname,"REDIRECT")) {
+       targetname=redirect_hostname;
+   }
+   if(!strcasecmp(targetservice,"REDIRECT")) {
+       targetservice=redirect_port;
+   }
+
    Notice2("opening connection to %s:%s using socks5",
 	   targetname, targetservice);
 
-- 
1.7.0.3


From ef9569ae5030141fc4d317b15cf2bdc85b931368 Mon Sep 17 00:00:00 2001
From: Vitaly _Vi Shukela <public_vi@tut.by>
Date: Thu, 25 Mar 2010 17:43:57 +0200
Subject: [PATCH 4/4] Add information about REDIRECT to manual

---
 doc/socat.yo |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/doc/socat.yo b/doc/socat.yo
index dc83081..ce7aea8 100644
--- a/doc/socat.yo
+++ b/doc/socat.yo
@@ -253,6 +253,10 @@ left side (read, write, and bidirectional, as seen by this address). The second
 set describes the required direction on the right side; empty means it is an
 endpoint address form.
 
+If you specify "REDIRECT" instead of address or port, socat will use address provided by "tcp-l"
+thing retrieved usin <tt>SO_ORIGINAL_DST</tt> option of getsockopt. It is useful for redirecting users to SOCKS
+server by iptables. Example: <tt>socat tcp-l:1234 socks4:127.0.0.1:REDIRECT:REDIRECT</tt>
+
 When parsing the addresses within an address chain socat() takes care of the
 data transfer directions between consecutive addresses. For the first address
 the directions are bidirectional per default, or unidirectional when when
@@ -3365,6 +3369,11 @@ dit(bf(tt(socat - 'SSL,verify=0|SCTP6:ip6hostname:8888')))
 here two processes on different hosts communicate using openssl over SCTP on
 IPv6.
 
+label(EXAMPLE_REDIRECT_SOCKS5)
+dit(bf(tt(socat 'tcp-l:1234,reuseaddr,fork' 'socks5:REDIRECT:REDIRECT|tcp:127.0.0.1:1080')))
+
+Listen the port 1234 and connect to the redirected address using SOCKS5 server. Use <tt>iptables -t nat -A OUTPUT <limitations> -p tcp -j REDIRECT --to-ports 1234</tt> to set up the redirection rule.
+
 dit(bf(tt()))
 
 
@@ -3469,6 +3478,10 @@ link(UDP-LISTEN)(ADDRESS_UDP_LISTEN), and
 link(SCTP-LISTEN)(ADDRESS_SCTP_LISTEN) addresses, this variable is set to the
 local port.
 
+dit(bf(SOCAT_DESTADDR) (output)) With all TCP-LISTEN, UDP-LISTEN, this variable is set to a string describing the destination (SO_ORIGINAL_DST) socket address.
+
+dit(bf(SOCAT_DESTPORT) (output)) With TCP-LISTEN, UDP-LISTEN, this variable is set to the destination (SO_ORIGINAL_DST) port.
+
 dit(bf(SOCAT_TIMESTAMP) (output)) With all RECVFROM addresses where address
 option link(so-timestamp)(OPTION_SO_TIMESTAMP) is applied, socat() sets this
 variable to the resulting timestamp.
-- 
1.7.0.3