Allow to set up a source address for outgoing connections in zmq_connect()

Signed-off-by: Sergey Matveychuk <sem33@yandex-team.ru>
Signed-off-by: Martin Sustrik <sustik@250bpm.com>

6 files changed, 55 insertions, 25 deletions

diff --git a/AUTHORS b/AUTHORS
index 258a25d..c5ec023 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -66,6 +66,7 @@ Pieter Hintjens <ph@imatix.com>
 Piotr Trojanek <piotr.trojanek@gmail.com>
 Robert G. Jakabosky <bobby@sharedrealm.com>
 Sebastian Otaegui <feniix@gmail.com>
+Sergey Matveychuk <sem33@yandex-team.ru>
 Staffan Gimåker <staffan@spotify.com>
 Steven McCoy <steven.mccoy@miru.hk>
 Stuart Webster <sw_webster@hotmail.com>
diff --git a/doc/xs_tcp.txt b/doc/xs_tcp.txt
index 5d5cbca..b97be08 100644
--- a/doc/xs_tcp.txt
+++ b/doc/xs_tcp.txt
@@ -17,9 +17,10 @@ be your first choice.
 ADDRESSING
 ----------
 A Crossroads address string consists of two parts as follows:
-'transport'`://`'endpoint'. The 'transport' part specifies the underlying
-transport protocol to use, and for the TCP transport shall be set to `tcp`.
-The meaning of the 'endpoint' part for the TCP transport is defined below.
+'transport'`://[`'source address'`;]`'endpoint'. The 'transport' part specifies
+the underlying transport protocol to use, and for the TCP transport shall be
+set to `tcp`.  'source address' is optional. The meaning of the 'endpoint' part
+for the TCP transport is defined below.
 
 
 Assigning a local address to a socket
diff --git a/src/tcp_address.cpp b/src/tcp_address.cpp
index 3b6ed94..11f3793 100644
--- a/src/tcp_address.cpp
+++ b/src/tcp_address.cpp
@@ -250,11 +250,8 @@ int xs::tcp_address_t::resolve_interface (char const *interface_,
     int rc = resolve_nic_name (interface_, ipv4only_);
     if (rc != 0 && errno != ENODEV)
         return rc;
-    if (rc == 0) {
-        xs_assert (out_addrlen <= (socklen_t) sizeof (address));
-        memcpy (&address, out_addr, out_addrlen);
+    if (rc == 0)
         return 0;
-    }
 
     //  There's no such interface name. Assume literal address.
 #if defined XS_HAVE_OPENVMS && defined __ia64
@@ -369,31 +366,38 @@ xs::tcp_address_t::~tcp_address_t ()
 {
 }
 
-int xs::tcp_address_t::resolve (const char *name_, bool local_, bool ipv4only_)
+int xs::tcp_address_t::resolve (const char *name_, bool local_, bool ipv4only_,
+    bool ignore_port_)
 {
     //  Find the ':' at end that separates address from the port number.
     const char *delimiter = strrchr (name_, ':');
-    if (!delimiter) {
-        errno = EINVAL;
-        return -1;
-    }
+    std::string addr_str;
+    uint16_t port = 0;
+
+    if (!ignore_port_) {
+        if (!delimiter) {
+            errno = EINVAL;
+            return -1;
+        }
 
-    //  Separate the address/port.
-    std::string addr_str (name_, delimiter - name_);
-    std::string port_str (delimiter + 1);
+        //  Separate the address/port.
+        addr_str = std::string (name_, delimiter - name_);
+
+        //  Parse the port number (0 is not a valid port).
+        port = (uint16_t) atoi (delimiter+1);
+        if (port == 0) {
+            errno = EINVAL;
+            return -1;
+        }
+    }
+    else
+        addr_str = name_;
 
     //  Remove square brackets around the address, if any.
     if (!addr_str.empty () && addr_str [0] == '[' &&
           addr_str [addr_str.size () - 1] == ']')
         addr_str = addr_str.substr (1, addr_str.size () - 2);
 
-    //  Parse the port number (0 is not a valid port).
-    uint16_t port = (uint16_t) atoi (port_str.c_str());
-    if (port == 0) {
-        errno = EINVAL;
-        return -1;
-    }
-
     //  Resolve the IP address.
     int rc;
     if (local_)
diff --git a/src/tcp_address.hpp b/src/tcp_address.hpp
index 683f30f..4730cd7 100644
--- a/src/tcp_address.hpp
+++ b/src/tcp_address.hpp
@@ -45,7 +45,8 @@ namespace xs
         //  strcuture. If 'local' is true, names are resolved as local interface
         //  names. If it is false, names are resolved as remote hostnames.
         //  If 'ipv4only' is true, the name will never resolve to IPv6 address.
-        int resolve (const char* name_, bool local_, bool ipv4only_);
+        int resolve (const char* name_, bool local_, bool ipv4only_,
+            bool ignore_port_=false);
 
 #if defined XS_HAVE_WINDOWS
         unsigned short family ();
diff --git a/src/tcp_connecter.cpp b/src/tcp_connecter.cpp
index 2844a3b..36ddfa7 100644
--- a/src/tcp_connecter.cpp
+++ b/src/tcp_connecter.cpp
@@ -178,7 +178,23 @@ int xs::tcp_connecter_t::get_new_reconnect_ivl ()
 
 int xs::tcp_connecter_t::set_address (const char *addr_)
 {
-    return address.resolve (addr_, false, options.ipv4only ? true : false);
+    //  Find the ';'. It separates source address address from a destination.
+    const char *delimiter = strchr (addr_, ';');
+
+    std::string addr_str;
+    if (delimiter) {
+        std::string saddr_str (addr_, delimiter - addr_);
+        addr_str = delimiter + 1;
+        int rc = source_address.resolve (saddr_str.c_str(), true,
+            options.ipv4only ? true : false, true);
+        if (rc != 0)
+            return -1;
+    }
+    else
+        addr_str = addr_;
+
+    return address.resolve (addr_str.c_str(), false,
+        options.ipv4only ? true : false);
 }
 
 int xs::tcp_connecter_t::open ()
@@ -202,9 +218,13 @@ int xs::tcp_connecter_t::open ()
     if (address.family () == AF_INET6)
         enable_ipv4_mapping (s);
 
-    // Set the socket to non-blocking mode so that we get async connect().
+    //  Set the socket to non-blocking mode so that we get async connect().
     unblock_socket (s);
 
+    //  Set a source address for conversations.
+    if (source_address.family ())
+        ::bind (s, source_address.addr (), source_address.addrlen ());
+
     //  Connect to the remote peer.
     int rc = ::connect (s, address.addr (), address.addrlen ());
 
diff --git a/src/tcp_connecter.hpp b/src/tcp_connecter.hpp
index dcc909d..a174473 100644
--- a/src/tcp_connecter.hpp
+++ b/src/tcp_connecter.hpp
@@ -87,6 +87,9 @@ namespace xs
         //  Address to connect to.
         tcp_address_t address;
 
+        //  Source address.
+        tcp_address_t source_address;
+
         //  Underlying socket.
         fd_t s;