feature: add tcpsock:bind api

README.markdown

@@ -2926,6 +2926,7 @@ Nginx API for Lua
 * [udpsock:settimeout](#udpsocksettimeout)
 * [ngx.socket.stream](#ngxsocketstream)
 * [ngx.socket.tcp](#ngxsockettcp)
+* [tcpsock:bind](#tcpsockbind)
 * [tcpsock:connect](#tcpsockconnect)
 * [tcpsock:sslhandshake](#tcpsocksslhandshake)
 * [tcpsock:send](#tcpsocksend)
@@ -6383,6 +6384,7 @@ ngx.socket.tcp
 
 Creates and returns a TCP or stream-oriented unix domain socket object (also known as one type of the "cosocket" objects). The following methods are supported on this object:
 
+* [bind](#tcpsockbind)
 * [connect](#tcpsockconnect)
 * [sslhandshake](#tcpsocksslhandshake)
 * [send](#tcpsocksend)
@@ -6419,6 +6421,42 @@ See also [ngx.socket.udp](#ngxsocketudp).
 
 [Back to TOC](#nginx-api-for-lua)
 
+tcpsock:bind
+------------
+**syntax:** *ok, err = tcpsock:bind(address)*
+
+**context:** *rewrite_by_lua*, access_by_lua*, content_by_lua*, ngx.timer.*, ssl_certificate_by_lua**
+
+Just like the standard [proxy_bind](http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_bind) directive, this api makes the outgoing connection to a upstream server originate from the specified local IP address.
+
+Only IP addresses can be specified as the `address` argument.
+
+Here is an example for connecting to a TCP server from the specified local IP address:
+
+```nginx
+
+ location /test {
+     content_by_lua_block {
+         local sock = ngx.socket.tcp()
+         -- assume "192.168.1.10" is the local ip address
+         local ok, err = sock:bind("192.168.1.10")
+         if not ok then
+             ngx.say("failed to bind")
+             return
+         end
+         local ok, err = sock:connect("192.168.1.67", 80)
+         if not ok then
+             ngx.say("failed to connect server: ", err)
+             return
+         end
+         ngx.say("successfully connected!")
+         sock:close()
+     }
+ }
+```
+
+[Back to TOC](#nginx-api-for-lua)
+
 tcpsock:connect
 ---------------
 **syntax:** *ok, err = tcpsock:connect(host, port, options_table?)*

doc/HttpLuaModule.wiki

@@ -5347,6 +5347,7 @@ This API function was first added to the <code>v0.10.1</code> release.
 
 Creates and returns a TCP or stream-oriented unix domain socket object (also known as one type of the "cosocket" objects). The following methods are supported on this object:
 
+* [[#tcpsock:bind|bind]]
 * [[#tcpsock:connect|connect]]
 * [[#tcpsock:sslhandshake|sslhandshake]]
 * [[#tcpsock:send|send]]
@@ -5381,6 +5382,38 @@ This feature was first introduced in the <code>v0.5.0rc1</code> release.
 
 See also [[#ngx.socket.udp|ngx.socket.udp]].
 
+== tcpsock:bind ==
+'''syntax:''' ''ok, err = tcpsock:bind(address)''
+
+'''context:''' ''rewrite_by_lua*, access_by_lua*, content_by_lua*, ngx.timer.*, ssl_certificate_by_lua*''
+
+Just like the standard [[HttpProxyModule#proxy_bind|proxy_bind]] directive, this api makes the outgoing connection to a upstream server originate from the specified local IP address.
+
+Only IP addresses can be specified as the <code>address</code> argument.
+
+Here is an example for connecting to a TCP server from the specified local IP address:
+
+<geshi lang="nginx">
+    location /test {
+        content_by_lua_block {
+            local sock = ngx.socket.tcp()
+            -- assume "192.168.1.10" is the local ip address
+            local ok, err = sock:bind("192.168.1.10")
+            if not ok then
+                ngx.say("failed to bind")
+                return
+            end
+            local ok, err = sock:connect("192.168.1.67", 80)
+            if not ok then
+                ngx.say("failed to connect server: ", err)
+                return
+            end
+            ngx.say("successfully connected!")
+            sock:close()
+        }
+    }
+</geshi>
+
 == tcpsock:connect ==
 '''syntax:''' ''ok, err = tcpsock:connect(host, port, options_table?)''
 

src/ngx_http_lua_socket_tcp.c

@@ -19,6 +19,7 @@
 
 
 static int ngx_http_lua_socket_tcp(lua_State *L);
+static int ngx_http_lua_socket_tcp_bind(lua_State *L);
 static int ngx_http_lua_socket_tcp_connect(lua_State *L);
 #if (NGX_HTTP_SSL)
 static int ngx_http_lua_socket_tcp_sslhandshake(lua_State *L);
@@ -138,7 +139,8 @@ static void ngx_http_lua_socket_tcp_close_connection(ngx_connection_t *c);
 enum {
     SOCKET_CTX_INDEX = 1,
     SOCKET_TIMEOUT_INDEX = 2,
-    SOCKET_KEY_INDEX = 3
+    SOCKET_KEY_INDEX = 3,
+    SOCKET_BIND_INDEX = 4   /* only in upstream cosocket */
 };
 
 
@@ -266,7 +268,10 @@ ngx_http_lua_inject_socket_tcp_api(ngx_log_t *log, lua_State *L)
 
     /* {{{tcp object metatable */
     lua_pushlightuserdata(L, &ngx_http_lua_tcp_socket_metatable_key);
-    lua_createtable(L, 0 /* narr */, 11 /* nrec */);
+    lua_createtable(L, 0 /* narr */, 12 /* nrec */);
+
+    lua_pushcfunction(L, ngx_http_lua_socket_tcp_bind);
+    lua_setfield(L, -2, "bind");
 
     lua_pushcfunction(L, ngx_http_lua_socket_tcp_connect);
     lua_setfield(L, -2, "connect");
@@ -388,7 +393,7 @@ ngx_http_lua_socket_tcp(lua_State *L)
                                | NGX_HTTP_LUA_CONTEXT_TIMER
                                | NGX_HTTP_LUA_CONTEXT_SSL_CERT);
 
-    lua_createtable(L, 3 /* narr */, 1 /* nrec */);
+    lua_createtable(L, 4 /* narr */, 1 /* nrec */);
     lua_pushlightuserdata(L, &ngx_http_lua_tcp_socket_metatable_key);
     lua_rawget(L, LUA_REGISTRYINDEX);
     lua_setmetatable(L, -2);
@@ -399,6 +404,61 @@ ngx_http_lua_socket_tcp(lua_State *L)
 }
 
 
+static int
+ngx_http_lua_socket_tcp_bind(lua_State *L)
+{
+    ngx_http_request_t   *r;
+    ngx_http_lua_ctx_t   *ctx;
+    int                   n;
+    u_char               *text;
+    size_t                len;
+    ngx_addr_t           *local;
+
+    n = lua_gettop(L);
+
+    if (n != 2) {
+        return luaL_error(L, "expecting 2 arguments, but got %d",
+                          lua_gettop(L));
+    }
+
+    r = ngx_http_lua_get_req(L);
+    if (r == NULL) {
+        return luaL_error(L, "no request found");
+    }
+
+    ctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);
+    if (ctx == NULL) {
+        return luaL_error(L, "no ctx found");
+    }
+
+    ngx_http_lua_check_context(L, ctx, NGX_HTTP_LUA_CONTEXT_REWRITE
+                               | NGX_HTTP_LUA_CONTEXT_ACCESS
+                               | NGX_HTTP_LUA_CONTEXT_CONTENT
+                               | NGX_HTTP_LUA_CONTEXT_TIMER
+                               | NGX_HTTP_LUA_CONTEXT_SSL_CERT);
+
+    luaL_checktype(L, 1, LUA_TTABLE);
+
+    text = (u_char *) luaL_checklstring(L, 2, &len);
+
+    local = ngx_http_lua_parse_addr(L, text, len);
+    if (local == NULL) {
+        lua_pushnil(L);
+        lua_pushfstring(L, "bad address");
+        return 2;
+    }
+
+    /* TODO: we may reuse the userdata here */
+    lua_rawseti(L, 1, SOCKET_BIND_INDEX);
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua tcp socket bind ip: %V", &local->name);
+
+    lua_pushboolean(L, 1);
+    return 1;
+}
+
+
 static int
 ngx_http_lua_socket_tcp_connect(lua_State *L)
 {
@@ -416,6 +476,7 @@ ngx_http_lua_socket_tcp_connect(lua_State *L)
     ngx_int_t                    rc;
     ngx_http_lua_loc_conf_t     *llcf;
     ngx_peer_connection_t       *pc;
+    ngx_addr_t                  *local;
     int                          timeout;
     unsigned                     custom_pool;
     int                          key_index;
@@ -574,6 +635,14 @@ ngx_http_lua_socket_tcp_connect(lua_State *L)
 
     dd("lua peer connection log: %p", pc->log);
 
+    lua_rawgeti(L, 1, SOCKET_BIND_INDEX);
+    local = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+
+    if (local) {
+        u->peer.local = local;
+    }
+
     lua_rawgeti(L, 1, SOCKET_TIMEOUT_INDEX);
     timeout = (ngx_int_t) lua_tointeger(L, -1);
     lua_pop(L, 1);

src/ngx_http_lua_util.c

@@ -4097,4 +4097,75 @@ ngx_http_lua_cleanup_free(ngx_http_request_t *r, ngx_http_cleanup_pt *cleanup)
 }
 
 
+ngx_addr_t *
+ngx_http_lua_parse_addr(lua_State *L, u_char *text, size_t len)
+{
+    ngx_addr_t           *addr;
+    size_t                socklen;
+    in_addr_t             inaddr;
+    ngx_uint_t            family;
+    struct sockaddr_in   *sin;
+#if (NGX_HAVE_INET6)
+    struct in6_addr       inaddr6;
+    struct sockaddr_in6  *sin6;
+
+    /*
+     * prevent MSVC8 warning:
+     *    potentially uninitialized local variable 'inaddr6' used
+     */
+    ngx_memzero(&inaddr6, sizeof(struct in6_addr));
+#endif
+
+    inaddr = ngx_inet_addr(text, len);
+
+    if (inaddr != INADDR_NONE) {
+        family = AF_INET;
+        socklen = sizeof(struct sockaddr_in);
+
+#if (NGX_HAVE_INET6)
+    } else if (ngx_inet6_addr(text, len, inaddr6.s6_addr) == NGX_OK) {
+        family = AF_INET6;
+        socklen = sizeof(struct sockaddr_in6);
+
+#endif
+    } else {
+        return NULL;
+    }
+
+    addr = lua_newuserdata(L, sizeof(ngx_addr_t) + socklen + len);
+    if (addr == NULL) {
+        luaL_error(L, "no memory");
+        return NULL;
+    }
+
+    addr->sockaddr = (struct sockaddr *) ((u_char *) addr + sizeof(ngx_addr_t));
+
+    ngx_memzero(addr->sockaddr, socklen);
+
+    addr->sockaddr->sa_family = (u_char) family;
+    addr->socklen = socklen;
+
+    switch (family) {
+
+#if (NGX_HAVE_INET6)
+    case AF_INET6:
+        sin6 = (struct sockaddr_in6 *) addr->sockaddr;
+        ngx_memcpy(sin6->sin6_addr.s6_addr, inaddr6.s6_addr, 16);
+        break;
+#endif
+
+    default: /* AF_INET */
+        sin = (struct sockaddr_in *) addr->sockaddr;
+        sin->sin_addr.s_addr = inaddr;
+        break;
+    }
+
+    addr->name.data = (u_char *) addr->sockaddr + socklen;
+    addr->name.len = len;
+    ngx_memcpy(addr->name.data, text, len);
+
+    return addr;
+}
+
+
 /* vi:set ft=c ts=4 sw=4 et fdm=marker: */

src/ngx_http_lua_util.h

@@ -245,6 +245,8 @@ ngx_http_cleanup_t *ngx_http_lua_cleanup_add(ngx_http_request_t *r,
 void ngx_http_lua_cleanup_free(ngx_http_request_t *r,
     ngx_http_cleanup_pt *cleanup);
 
+ngx_addr_t *ngx_http_lua_parse_addr(lua_State *L, u_char *text, size_t len);
+
 
 #define ngx_http_lua_check_if_abortable(L, ctx)                             \
     if ((ctx)->no_abort) {                                                  \