openresty bundle

1 files changed, 1685 insertions, 0 deletions

diff --git a/ngx_lua-0.10.28/src/ngx_http_lua_socket_udp.c b/ngx_lua-0.10.28/src/ngx_http_lua_socket_udp.c
new file mode 100644
index 0000000..e2ba790
--- /dev/null
+++ b/ngx_lua-0.10.28/src/ngx_http_lua_socket_udp.c
@@ -0,0 +1,1685 @@
+
+/*
+ * Copyright (C) Yichun Zhang (agentzh)
+ */
+
+
+#ifndef DDEBUG
+#define DDEBUG 0
+#endif
+#include "ddebug.h"
+
+
+#include "ngx_http_lua_socket_udp.h"
+#include "ngx_http_lua_socket_tcp.h"
+#include "ngx_http_lua_util.h"
+#include "ngx_http_lua_contentby.h"
+#include "ngx_http_lua_output.h"
+#include "ngx_http_lua_probe.h"
+
+
+#if 1
+#undef ngx_http_lua_probe_info
+#define ngx_http_lua_probe_info(msg)
+#endif
+
+
+#define UDP_MAX_DATAGRAM_SIZE 65536
+
+
+static int ngx_http_lua_socket_udp(lua_State *L);
+static int ngx_http_lua_socket_udp_setpeername(lua_State *L);
+static int ngx_http_lua_socket_udp_send(lua_State *L);
+static int ngx_http_lua_socket_udp_receive(lua_State *L);
+static int ngx_http_lua_socket_udp_settimeout(lua_State *L);
+static void ngx_http_lua_socket_udp_finalize(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u);
+static int ngx_http_lua_socket_udp_upstream_destroy(lua_State *L);
+static int ngx_http_lua_socket_resolve_retval_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u, lua_State *L);
+static void ngx_http_lua_socket_resolve_handler(ngx_resolver_ctx_t *ctx);
+static int ngx_http_lua_socket_error_retval_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u, lua_State *L);
+static void ngx_http_lua_socket_udp_handle_error(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u, ngx_uint_t ft_type);
+static void ngx_http_lua_socket_udp_cleanup(void *data);
+static void ngx_http_lua_socket_udp_handler(ngx_event_t *ev);
+static void ngx_http_lua_socket_dummy_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u);
+static int ngx_http_lua_socket_udp_receive_retval_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u, lua_State *L);
+static ngx_int_t ngx_http_lua_socket_udp_read(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u);
+static void ngx_http_lua_socket_udp_read_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u);
+static void ngx_http_lua_socket_udp_handle_success(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u);
+static ngx_int_t ngx_http_lua_udp_connect(ngx_http_lua_udp_connection_t *uc,
+    ngx_addr_t *local);
+static int ngx_http_lua_socket_udp_close(lua_State *L);
+static ngx_int_t ngx_http_lua_socket_udp_resume(ngx_http_request_t *r);
+static void ngx_http_lua_udp_resolve_cleanup(void *data);
+static void ngx_http_lua_udp_socket_cleanup(void *data);
+static int ngx_http_lua_socket_udp_bind(lua_State *L);
+
+
+enum {
+    SOCKET_CTX_INDEX = 1,
+    SOCKET_TIMEOUT_INDEX = 2,
+    SOCKET_BIND_INDEX = 3,
+};
+
+
+static char ngx_http_lua_socket_udp_metatable_key;
+static char ngx_http_lua_udp_udata_metatable_key;
+static u_char ngx_http_lua_socket_udp_buffer[UDP_MAX_DATAGRAM_SIZE];
+
+
+void
+ngx_http_lua_inject_socket_udp_api(ngx_log_t *log, lua_State *L)
+{
+    lua_getfield(L, -1, "socket"); /* ngx socket */
+
+    lua_pushcfunction(L, ngx_http_lua_socket_udp);
+    lua_setfield(L, -2, "udp"); /* ngx socket */
+
+    /* udp socket object metatable */
+    lua_pushlightuserdata(L, ngx_http_lua_lightudata_mask(
+                          socket_udp_metatable_key));
+    lua_createtable(L, 0 /* narr */, 6 /* nrec */);
+
+    lua_pushcfunction(L, ngx_http_lua_socket_udp_setpeername);
+    lua_setfield(L, -2, "setpeername"); /* ngx socket mt */
+
+    lua_pushcfunction(L, ngx_http_lua_socket_udp_send);
+    lua_setfield(L, -2, "send");
+
+    lua_pushcfunction(L, ngx_http_lua_socket_udp_receive);
+    lua_setfield(L, -2, "receive");
+
+    lua_pushcfunction(L, ngx_http_lua_socket_udp_settimeout);
+    lua_setfield(L, -2, "settimeout"); /* ngx socket mt */
+
+    lua_pushcfunction(L, ngx_http_lua_socket_udp_close);
+    lua_setfield(L, -2, "close"); /* ngx socket mt */
+
+    lua_pushcfunction(L, ngx_http_lua_socket_udp_bind);
+    lua_setfield(L, -2, "bind");
+
+    lua_pushvalue(L, -1);
+    lua_setfield(L, -2, "__index");
+    lua_rawset(L, LUA_REGISTRYINDEX);
+    /* }}} */
+
+    /* udp socket object metatable */
+    lua_pushlightuserdata(L, ngx_http_lua_lightudata_mask(
+                          udp_udata_metatable_key));
+    lua_createtable(L, 0 /* narr */, 1 /* nrec */); /* metatable */
+    lua_pushcfunction(L, ngx_http_lua_socket_udp_upstream_destroy);
+    lua_setfield(L, -2, "__gc");
+    lua_rawset(L, LUA_REGISTRYINDEX);
+    /* }}} */
+
+    lua_pop(L, 1);
+}
+
+
+static int
+ngx_http_lua_socket_udp(lua_State *L)
+{
+    ngx_http_request_t      *r;
+    ngx_http_lua_ctx_t      *ctx;
+
+    if (lua_gettop(L) != 0) {
+        return luaL_error(L, "expecting zero 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_YIELDABLE);
+
+    lua_createtable(L, 3 /* narr */, 1 /* nrec */);
+    lua_pushlightuserdata(L, ngx_http_lua_lightudata_mask(
+                          socket_udp_metatable_key));
+    lua_rawget(L, LUA_REGISTRYINDEX);
+    lua_setmetatable(L, -2);
+
+    dd("top: %d", lua_gettop(L));
+
+    return 1;
+}
+
+
+static int
+ngx_http_lua_socket_udp_setpeername(lua_State *L)
+{
+    ngx_http_request_t          *r;
+    ngx_http_lua_ctx_t          *ctx;
+    ngx_str_t                    host;
+    ngx_addr_t                  *local;
+    int                          port;
+    ngx_resolver_ctx_t          *rctx, temp;
+    ngx_http_core_loc_conf_t    *clcf;
+    int                          saved_top;
+    int                          n;
+    u_char                      *p;
+    size_t                       len;
+    ngx_url_t                    url;
+    ngx_int_t                    rc;
+    ngx_http_lua_loc_conf_t     *llcf;
+    int                          timeout;
+    ngx_http_lua_co_ctx_t       *coctx;
+
+    ngx_http_lua_udp_connection_t           *uc;
+    ngx_http_lua_socket_udp_upstream_t      *u;
+
+    /*
+     * TODO: we should probably accept an extra argument to setpeername()
+     * to allow the user bind the datagram unix domain socket himself,
+     * which is necessary for systems without autobind support.
+     */
+
+    n = lua_gettop(L);
+    if (n != 2 && n != 3) {
+        return luaL_error(L, "ngx.socket.udp setpeername: expecting 2 or 3 "
+                          "arguments (including the object), but seen %d", n);
+    }
+
+    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_YIELDABLE);
+
+    luaL_checktype(L, 1, LUA_TTABLE);
+
+    p = (u_char *) luaL_checklstring(L, 2, &len);
+
+    host.data = ngx_palloc(r->pool, len + 1);
+    if (host.data == NULL) {
+        return luaL_error(L, "no memory");
+    }
+
+    host.len = len;
+
+    ngx_memcpy(host.data, p, len);
+    host.data[len] = '\0';
+
+    if (n == 3) {
+        port = luaL_checkinteger(L, 3);
+
+        if (port < 0 || port > 65535) {
+            lua_pushnil(L);
+            lua_pushfstring(L, "bad port number: %d", port);
+            return 2;
+        }
+
+    } else { /* n == 2 */
+        port = 0;
+    }
+
+    lua_rawgeti(L, 1, SOCKET_CTX_INDEX);
+    u = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+
+    if (u) {
+        if (u->request && u->request != r) {
+            return luaL_error(L, "bad request");
+        }
+
+        if (u->waiting) {
+            lua_pushnil(L);
+            lua_pushliteral(L, "socket busy");
+            return 2;
+        }
+
+        if (u->udp_connection.connection) {
+            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "lua udp socket reconnect without shutting down");
+
+            ngx_http_lua_socket_udp_finalize(r, u);
+        }
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "lua reuse socket upstream ctx");
+
+    } else {
+        u = lua_newuserdata(L, sizeof(ngx_http_lua_socket_udp_upstream_t));
+        if (u == NULL) {
+            return luaL_error(L, "no memory");
+        }
+
+#if 1
+        lua_pushlightuserdata(L, ngx_http_lua_lightudata_mask(
+                              udp_udata_metatable_key));
+        lua_rawget(L, LUA_REGISTRYINDEX);
+        lua_setmetatable(L, -2);
+#endif
+
+        lua_rawseti(L, 1, SOCKET_CTX_INDEX);
+    }
+
+    ngx_memzero(u, sizeof(ngx_http_lua_socket_udp_upstream_t));
+
+    u->request = r; /* set the controlling request */
+    llcf = ngx_http_get_module_loc_conf(r, ngx_http_lua_module);
+
+    u->conf = llcf;
+
+    uc = &u->udp_connection;
+
+    uc->log = *r->connection->log;
+
+    dd("lua peer connection log: %p", &uc->log);
+
+    lua_rawgeti(L, 1, SOCKET_TIMEOUT_INDEX);
+    timeout = (ngx_int_t) lua_tointeger(L, -1);
+    lua_pop(L, 1);
+
+    if (timeout > 0) {
+        u->read_timeout = (ngx_msec_t) timeout;
+
+    } else {
+        u->read_timeout = u->conf->read_timeout;
+    }
+
+    lua_rawgeti(L, 1, SOCKET_BIND_INDEX);
+    local = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+    if (local != NULL) {
+        u->local = local;
+    }
+
+    ngx_memzero(&url, sizeof(ngx_url_t));
+
+    url.url.len = host.len;
+    url.url.data = host.data;
+    url.default_port = (in_port_t) port;
+    url.no_resolve = 1;
+
+    if (ngx_parse_url(r->pool, &url) != NGX_OK) {
+        lua_pushnil(L);
+
+        if (url.err) {
+            lua_pushfstring(L, "failed to parse host name \"%s\": %s",
+                            host.data, url.err);
+
+        } else {
+            lua_pushfstring(L, "failed to parse host name \"%s\"", host.data);
+        }
+
+        return 2;
+    }
+
+    u->resolved = ngx_pcalloc(r->pool, sizeof(ngx_http_upstream_resolved_t));
+    if (u->resolved == NULL) {
+        return luaL_error(L, "no memory");
+    }
+
+    if (url.addrs && url.addrs[0].sockaddr) {
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "lua udp socket network address given directly");
+
+        u->resolved->sockaddr = url.addrs[0].sockaddr;
+        u->resolved->socklen = url.addrs[0].socklen;
+        u->resolved->naddrs = 1;
+        u->resolved->host = url.addrs[0].name;
+
+    } else {
+        u->resolved->host = host;
+        u->resolved->port = (in_port_t) port;
+    }
+
+    if (u->resolved->sockaddr) {
+        rc = ngx_http_lua_socket_resolve_retval_handler(r, u, L);
+        if (rc == NGX_AGAIN) {
+            return lua_yield(L, 0);
+        }
+
+        return rc;
+    }
+
+    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+
+    temp.name = host;
+    rctx = ngx_resolve_start(clcf->resolver, &temp);
+    if (rctx == NULL) {
+        u->ft_type |= NGX_HTTP_LUA_SOCKET_FT_RESOLVER;
+        lua_pushnil(L);
+        lua_pushliteral(L, "failed to start the resolver");
+        return 2;
+    }
+
+    if (rctx == NGX_NO_RESOLVER) {
+        u->ft_type |= NGX_HTTP_LUA_SOCKET_FT_RESOLVER;
+        lua_pushnil(L);
+        lua_pushfstring(L, "no resolver defined to resolve \"%s\"", host.data);
+        return 2;
+    }
+
+    rctx->name = host;
+    rctx->handler = ngx_http_lua_socket_resolve_handler;
+    rctx->data = u;
+    rctx->timeout = clcf->resolver_timeout;
+
+    u->co_ctx = ctx->cur_co_ctx;
+    u->resolved->ctx = rctx;
+
+    saved_top = lua_gettop(L);
+
+    coctx = ctx->cur_co_ctx;
+    ngx_http_lua_cleanup_pending_operation(coctx);
+    coctx->cleanup = ngx_http_lua_udp_resolve_cleanup;
+
+    if (ngx_resolve_name(rctx) != NGX_OK) {
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "lua udp socket fail to run resolver immediately");
+
+        u->ft_type |= NGX_HTTP_LUA_SOCKET_FT_RESOLVER;
+
+        u->resolved->ctx = NULL;
+        lua_pushnil(L);
+        lua_pushfstring(L, "%s could not be resolved", host.data);
+
+        return 2;
+    }
+
+    if (u->waiting == 1) {
+        /* resolved and already connecting */
+        return lua_yield(L, 0);
+    }
+
+    n = lua_gettop(L) - saved_top;
+    if (n) {
+        /* errors occurred during resolving or connecting
+         * or already connected */
+        return n;
+    }
+
+    /* still resolving */
+
+    u->waiting = 1;
+    u->prepare_retvals = ngx_http_lua_socket_resolve_retval_handler;
+
+    coctx->data = u;
+
+    if (ctx->entered_content_phase) {
+        r->write_event_handler = ngx_http_lua_content_wev_handler;
+
+    } else {
+        r->write_event_handler = ngx_http_core_run_phases;
+    }
+
+    return lua_yield(L, 0);
+}
+
+
+static void
+ngx_http_lua_socket_resolve_handler(ngx_resolver_ctx_t *ctx)
+{
+    ngx_http_request_t                  *r;
+    ngx_connection_t                    *c;
+    ngx_http_upstream_resolved_t        *ur;
+    ngx_http_lua_ctx_t                  *lctx;
+    lua_State                           *L;
+    ngx_http_lua_socket_udp_upstream_t  *u;
+    u_char                              *p;
+    size_t                               len;
+    socklen_t                            socklen;
+    struct sockaddr                     *sockaddr;
+    ngx_uint_t                           i;
+    unsigned                             waiting;
+
+    u = ctx->data;
+    r = u->request;
+    c = r->connection;
+    ur = u->resolved;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "lua udp socket resolve handler");
+
+    lctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);
+    if (lctx == NULL) {
+        return;
+    }
+
+    lctx->cur_co_ctx = u->co_ctx;
+
+    u->co_ctx->cleanup = NULL;
+
+    L = lctx->cur_co_ctx->co;
+
+    dd("setting socket_ready to 1");
+
+    waiting = u->waiting;
+
+    if (ctx->state) {
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                       "lua udp socket resolver error: %s (waiting: %d)",
+                       ngx_resolver_strerror(ctx->state), (int) u->waiting);
+
+        lua_pushnil(L);
+        lua_pushlstring(L, (char *) ctx->name.data, ctx->name.len);
+        lua_pushfstring(L, " could not be resolved (%d: %s)",
+                        (int) ctx->state,
+                        ngx_resolver_strerror(ctx->state));
+        lua_concat(L, 2);
+
+#if 1
+        ngx_resolve_name_done(ctx);
+        ur->ctx = NULL;
+#endif
+
+        u->prepare_retvals = ngx_http_lua_socket_error_retval_handler;
+        ngx_http_lua_socket_udp_handle_error(r, u,
+                                             NGX_HTTP_LUA_SOCKET_FT_RESOLVER);
+
+        if (waiting) {
+            ngx_http_run_posted_requests(c);
+        }
+
+        return;
+    }
+
+    ur->naddrs = ctx->naddrs;
+    ur->addrs = ctx->addrs;
+
+#if (NGX_DEBUG)
+    {
+        u_char      text[NGX_SOCKADDR_STRLEN];
+        ngx_str_t   addr;
+        ngx_uint_t  i;
+
+        addr.data = text;
+
+        for (i = 0; i < ctx->naddrs; i++) {
+            addr.len = ngx_sock_ntop(ur->addrs[i].sockaddr,
+                                     ur->addrs[i].socklen, text,
+                                     NGX_SOCKADDR_STRLEN, 0);
+
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "name was resolved to %V", &addr);
+        }
+    }
+#endif
+
+    ngx_http_lua_assert(ur->naddrs > 0);
+
+    if (ur->naddrs == 1) {
+        i = 0;
+
+    } else {
+        i = ngx_random() % ur->naddrs;
+    }
+
+    dd("selected addr index: %d", (int) i);
+
+    socklen = ur->addrs[i].socklen;
+
+    sockaddr = ngx_palloc(r->pool, socklen);
+    if (sockaddr == NULL) {
+        goto nomem;
+    }
+
+    ngx_memcpy(sockaddr, ur->addrs[i].sockaddr, socklen);
+
+    switch (sockaddr->sa_family) {
+#if (NGX_HAVE_INET6)
+    case AF_INET6:
+        ((struct sockaddr_in6 *) sockaddr)->sin6_port = htons(ur->port);
+        break;
+#endif
+    default: /* AF_INET */
+        ((struct sockaddr_in *) sockaddr)->sin_port = htons(ur->port);
+    }
+
+    p = ngx_pnalloc(r->pool, NGX_SOCKADDR_STRLEN);
+    if (p == NULL) {
+        goto nomem;
+    }
+
+    len = ngx_sock_ntop(sockaddr, socklen, p, NGX_SOCKADDR_STRLEN, 1);
+    ur->sockaddr = sockaddr;
+    ur->socklen = socklen;
+
+    ur->host.data = p;
+    ur->host.len = len;
+    ur->naddrs = 1;
+
+    ngx_resolve_name_done(ctx);
+    ur->ctx = NULL;
+
+    u->waiting = 0;
+
+    if (waiting) {
+        lctx->resume_handler = ngx_http_lua_socket_udp_resume;
+        r->write_event_handler(r);
+        ngx_http_run_posted_requests(c);
+
+    } else {
+        (void) ngx_http_lua_socket_resolve_retval_handler(r, u, L);
+    }
+
+    return;
+
+nomem:
+
+    if (ur->ctx) {
+        ngx_resolve_name_done(ctx);
+        ur->ctx = NULL;
+    }
+
+    u->prepare_retvals = ngx_http_lua_socket_error_retval_handler;
+    ngx_http_lua_socket_udp_handle_error(r, u,
+                                         NGX_HTTP_LUA_SOCKET_FT_NOMEM);
+
+    if (waiting) {
+        ngx_http_run_posted_requests(c);
+
+    } else {
+        lua_pushnil(L);
+        lua_pushliteral(L, "no memory");
+    }
+}
+
+
+static int
+ngx_http_lua_socket_resolve_retval_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u, lua_State *L)
+{
+    ngx_http_lua_ctx_t              *ctx;
+    ngx_http_lua_co_ctx_t           *coctx;
+    ngx_connection_t                *c;
+    ngx_pool_cleanup_t              *cln;
+    ngx_http_upstream_resolved_t    *ur;
+    ngx_int_t                        rc;
+    ngx_http_lua_udp_connection_t   *uc;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket resolve retval handler");
+
+    if (u->ft_type & NGX_HTTP_LUA_SOCKET_FT_RESOLVER) {
+        return 2;
+    }
+
+    uc = &u->udp_connection;
+
+    ur = u->resolved;
+
+    if (ur->sockaddr) {
+        uc->sockaddr = ur->sockaddr;
+        uc->socklen = ur->socklen;
+        uc->server = ur->host;
+
+    } else {
+        lua_pushnil(L);
+        lua_pushliteral(L, "resolver not working");
+        return 2;
+    }
+
+    rc = ngx_http_lua_udp_connect(uc, u->local);
+
+    if (rc != NGX_OK) {
+        u->socket_errno = ngx_socket_errno;
+    }
+
+    if (u->cleanup == NULL) {
+        cln = ngx_pool_cleanup_add(r->pool, 0);
+        if (cln == NULL) {
+            u->ft_type |= NGX_HTTP_LUA_SOCKET_FT_ERROR;
+            lua_pushnil(L);
+            lua_pushliteral(L, "no memory");
+            return 2;
+        }
+
+        cln->handler = ngx_http_lua_socket_udp_cleanup;
+        cln->data = u;
+        u->cleanup = &cln->handler;
+    }
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket connect: %i", rc);
+
+    if (rc != NGX_OK) {
+        return ngx_http_lua_socket_error_retval_handler(r, u, L);
+    }
+
+    /* rc == NGX_OK */
+
+    c = uc->connection;
+
+    c->data = u;
+
+    c->write->handler = NULL;
+    c->read->handler = ngx_http_lua_socket_udp_handler;
+    c->read->resolver = 0;
+
+    c->pool = r->pool;
+    c->log = r->connection->log;
+    c->read->log = c->log;
+    c->write->log = c->log;
+
+    ctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);
+
+    coctx = ctx->cur_co_ctx;
+
+    coctx->data = u;
+
+    u->read_event_handler = ngx_http_lua_socket_dummy_handler;
+
+    lua_pushinteger(L, 1);
+    return 1;
+}
+
+
+static int
+ngx_http_lua_socket_error_retval_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u, lua_State *L)
+{
+    u_char           errstr[NGX_MAX_ERROR_STR];
+    u_char          *p;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket error retval handler");
+
+    if (u->ft_type & NGX_HTTP_LUA_SOCKET_FT_RESOLVER) {
+        return 2;
+    }
+
+    lua_pushnil(L);
+
+    if (u->ft_type & NGX_HTTP_LUA_SOCKET_FT_PARTIALWRITE) {
+        lua_pushliteral(L, "partial write");
+
+    } else if (u->ft_type & NGX_HTTP_LUA_SOCKET_FT_TIMEOUT) {
+        lua_pushliteral(L, "timeout");
+
+    } else if (u->ft_type & NGX_HTTP_LUA_SOCKET_FT_CLOSED) {
+        lua_pushliteral(L, "closed");
+
+    } else if (u->ft_type & NGX_HTTP_LUA_SOCKET_FT_BUFTOOSMALL) {
+        lua_pushliteral(L, "buffer too small");
+
+    } else if (u->ft_type & NGX_HTTP_LUA_SOCKET_FT_NOMEM) {
+        lua_pushliteral(L, "no memory");
+
+    } else {
+
+        if (u->socket_errno) {
+            p = ngx_strerror(u->socket_errno, errstr, sizeof(errstr));
+            /* for compatibility with LuaSocket */
+            ngx_strlow(errstr, errstr, p - errstr);
+            lua_pushlstring(L, (char *) errstr, p - errstr);
+
+        } else {
+            lua_pushliteral(L, "error");
+        }
+    }
+
+    return 2;
+}
+
+
+static int
+ngx_http_lua_socket_udp_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_YIELDABLE);
+
+    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;
+    }
+
+    lua_rawseti(L, 1, SOCKET_BIND_INDEX);
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket bind ip: %V", &local->name);
+
+    lua_pushinteger(L, 1);
+    return 1;
+}
+
+
+static int
+ngx_http_lua_socket_udp_send(lua_State *L)
+{
+    ssize_t                              n;
+    ngx_http_request_t                  *r;
+    u_char                              *p;
+    u_char                              *str;
+    size_t                               len;
+    ngx_http_lua_socket_udp_upstream_t  *u;
+    int                                  type;
+    const char                          *msg;
+    ngx_str_t                            query;
+    ngx_http_lua_loc_conf_t             *llcf;
+
+    if (lua_gettop(L) != 2) {
+        return luaL_error(L, "expecting 2 arguments (including the object), "
+                          "but got %d", lua_gettop(L));
+    }
+
+    r = ngx_http_lua_get_req(L);
+    if (r == NULL) {
+        return luaL_error(L, "request object not found");
+    }
+
+    luaL_checktype(L, 1, LUA_TTABLE);
+
+    lua_rawgeti(L, 1, SOCKET_CTX_INDEX);
+    u = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+
+    if (u == NULL || u->udp_connection.connection == NULL) {
+        llcf = ngx_http_get_module_loc_conf(r, ngx_http_lua_module);
+
+        if (llcf->log_socket_errors) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "attempt to send data on a closed socket: u:%p, c:%p",
+                          u, u ? u->udp_connection.connection : NULL);
+        }
+
+        lua_pushnil(L);
+        lua_pushliteral(L, "closed");
+        return 2;
+    }
+
+    if (u->request != r) {
+        return luaL_error(L, "bad request");
+    }
+
+    if (u->ft_type) {
+        u->ft_type = 0;
+    }
+
+    if (u->waiting) {
+        lua_pushnil(L);
+        lua_pushliteral(L, "socket busy");
+        return 2;
+    }
+
+    type = lua_type(L, 2);
+    switch (type) {
+        case LUA_TNUMBER:
+            len = ngx_http_lua_get_num_len(L, 2);
+            break;
+
+        case LUA_TSTRING:
+            lua_tolstring(L, 2, &len);
+            break;
+
+        case LUA_TTABLE:
+            /* The maximum possible length, not the actual length */
+            len = ngx_http_lua_calc_strlen_in_table(L, 2, 2, 1 /* strict */);
+            break;
+
+        case LUA_TNIL:
+            len = sizeof("nil") - 1;
+            break;
+
+        case LUA_TBOOLEAN:
+            if (lua_toboolean(L, 2)) {
+                len = sizeof("true") - 1;
+
+            } else {
+                len = sizeof("false") - 1;
+            }
+
+            break;
+
+        default:
+            msg = lua_pushfstring(L, "string, number, boolean, nil, "
+                                  "or array table expected, got %s",
+                                  lua_typename(L, type));
+
+            return luaL_argerror(L, 2, msg);
+    }
+
+    query.data = lua_newuserdata(L, len);
+    p = query.data;
+
+    switch (type) {
+        case LUA_TNUMBER:
+            p = ngx_http_lua_write_num(L, 2, p);
+            break;
+
+        case LUA_TSTRING:
+            str = (u_char *) lua_tolstring(L, 2, &len);
+            p = ngx_cpymem(p, (u_char *) str, len);
+            break;
+
+        case LUA_TTABLE:
+            p = ngx_http_lua_copy_str_in_table(L, 2, p);
+            break;
+
+        case LUA_TNIL:
+            *p++ = 'n';
+            *p++ = 'i';
+            *p++ = 'l';
+            break;
+
+        case LUA_TBOOLEAN:
+            if (lua_toboolean(L, 2)) {
+                *p++ = 't';
+                *p++ = 'r';
+                *p++ = 'u';
+                *p++ = 'e';
+
+            } else {
+                *p++ = 'f';
+                *p++ = 'a';
+                *p++ = 'l';
+                *p++ = 's';
+                *p++ = 'e';
+            }
+
+            break;
+
+        default:
+            return luaL_error(L, "impossible to reach here");
+    }
+
+    query.len = p - query.data;
+    ngx_http_lua_assert(query.len <= len);
+
+    u->ft_type = 0;
+
+    /* mimic ngx_http_upstream_init_request here */
+
+#if 1
+    u->waiting = 0;
+#endif
+
+    dd("sending query %.*s", (int) query.len, query.data);
+
+    n = ngx_send(u->udp_connection.connection, query.data, query.len);
+
+    dd("ngx_send returns %d (query len %d)", (int) n, (int) query.len);
+
+    if (n == NGX_ERROR || n == NGX_AGAIN) {
+        u->socket_errno = ngx_socket_errno;
+
+        return ngx_http_lua_socket_error_retval_handler(r, u, L);
+    }
+
+    if (n != (ssize_t) query.len) {
+        dd("not the while query was sent");
+
+        u->ft_type |= NGX_HTTP_LUA_SOCKET_FT_PARTIALWRITE;
+        return ngx_http_lua_socket_error_retval_handler(r, u, L);
+    }
+
+    dd("n == len");
+
+    lua_pushinteger(L, 1);
+    return 1;
+}
+
+
+static int
+ngx_http_lua_socket_udp_receive(lua_State *L)
+{
+    ngx_http_request_t                  *r;
+    ngx_http_lua_socket_udp_upstream_t  *u;
+    ngx_int_t                            rc;
+    ngx_http_lua_ctx_t                  *ctx;
+    ngx_http_lua_co_ctx_t               *coctx;
+    size_t                               size;
+    int                                  nargs;
+    ngx_http_lua_loc_conf_t             *llcf;
+
+    nargs = lua_gettop(L);
+    if (nargs != 1 && nargs != 2) {
+        return luaL_error(L, "expecting 1 or 2 arguments "
+                          "(including the object), but got %d", nargs);
+    }
+
+    r = ngx_http_lua_get_req(L);
+    if (r == NULL) {
+        return luaL_error(L, "no request found");
+    }
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket calling receive() method");
+
+    luaL_checktype(L, 1, LUA_TTABLE);
+
+    lua_rawgeti(L, 1, SOCKET_CTX_INDEX);
+    u = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+
+    if (u == NULL || u->udp_connection.connection == NULL) {
+        llcf = ngx_http_get_module_loc_conf(r, ngx_http_lua_module);
+
+        if (llcf->log_socket_errors) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "attempt to receive data on a closed socket: u:%p, "
+                          "c:%p", u, u ? u->udp_connection.connection : NULL);
+        }
+
+        lua_pushnil(L);
+        lua_pushliteral(L, "closed");
+        return 2;
+    }
+
+    if (u->request != r) {
+        return luaL_error(L, "bad request");
+    }
+
+    if (u->ft_type) {
+        u->ft_type = 0;
+    }
+
+#if 1
+    if (u->waiting) {
+        lua_pushnil(L);
+        lua_pushliteral(L, "socket busy");
+        return 2;
+    }
+#endif
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket read timeout: %M", u->read_timeout);
+
+    size = (size_t) luaL_optnumber(L, 2, UDP_MAX_DATAGRAM_SIZE);
+    size = ngx_min(size, UDP_MAX_DATAGRAM_SIZE);
+
+    u->recv_buf_size = size;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket receive buffer size: %uz", u->recv_buf_size);
+
+    rc = ngx_http_lua_socket_udp_read(r, u);
+
+    if (rc == NGX_ERROR) {
+        dd("read failed: %d", (int) u->ft_type);
+        rc = ngx_http_lua_socket_udp_receive_retval_handler(r, u, L);
+        dd("udp receive retval returned: %d", (int) rc);
+        return rc;
+    }
+
+    if (rc == NGX_OK) {
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "lua udp socket receive done in a single run");
+
+        return ngx_http_lua_socket_udp_receive_retval_handler(r, u, L);
+    }
+
+    /* n == NGX_AGAIN */
+
+    u->read_event_handler = ngx_http_lua_socket_udp_read_handler;
+
+    ctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);
+    if (ctx == NULL) {
+        return luaL_error(L, "no request ctx found");
+    }
+
+    coctx = ctx->cur_co_ctx;
+
+    ngx_http_lua_cleanup_pending_operation(coctx);
+    coctx->cleanup = ngx_http_lua_udp_socket_cleanup;
+    coctx->data = u;
+
+    if (ctx->entered_content_phase) {
+        r->write_event_handler = ngx_http_lua_content_wev_handler;
+
+    } else {
+        r->write_event_handler = ngx_http_core_run_phases;
+    }
+
+    u->co_ctx = coctx;
+    u->waiting = 1;
+    u->prepare_retvals = ngx_http_lua_socket_udp_receive_retval_handler;
+
+    return lua_yield(L, 0);
+}
+
+
+static int
+ngx_http_lua_socket_udp_receive_retval_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u, lua_State *L)
+{
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket receive return value handler");
+
+    if (u->ft_type) {
+        return ngx_http_lua_socket_error_retval_handler(r, u, L);
+    }
+
+    lua_pushlstring(L, (char *) ngx_http_lua_socket_udp_buffer, u->received);
+    return 1;
+}
+
+
+static int
+ngx_http_lua_socket_udp_settimeout(lua_State *L)
+{
+    int                     n;
+    ngx_int_t               timeout;
+
+    ngx_http_lua_socket_udp_upstream_t  *u;
+
+    n = lua_gettop(L);
+
+    if (n != 2) {
+        return luaL_error(L, "ngx.socket settimeout: expecting at least 2 "
+                          "arguments (including the object) but seen %d",
+                          lua_gettop(L));
+    }
+
+    timeout = (ngx_int_t) lua_tonumber(L, 2);
+
+    lua_rawseti(L, 1, SOCKET_TIMEOUT_INDEX);
+
+    lua_rawgeti(L, 1, SOCKET_CTX_INDEX);
+    u = lua_touserdata(L, -1);
+
+    if (u) {
+        if (timeout > 0) {
+            u->read_timeout = (ngx_msec_t) timeout;
+
+        } else {
+            u->read_timeout = u->conf->read_timeout;
+        }
+    }
+
+    return 0;
+}
+
+
+static void
+ngx_http_lua_socket_udp_finalize(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u)
+{
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua finalize socket");
+
+    if (u->cleanup) {
+        *u->cleanup = NULL;
+        u->cleanup = NULL;
+    }
+
+    if (u->resolved && u->resolved->ctx) {
+        ngx_resolve_name_done(u->resolved->ctx);
+        u->resolved->ctx = NULL;
+    }
+
+    if (u->udp_connection.connection) {
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "lua close socket connection");
+
+        ngx_close_connection(u->udp_connection.connection);
+        u->udp_connection.connection = NULL;
+    }
+
+    if (u->waiting) {
+        u->waiting = 0;
+    }
+}
+
+
+static int
+ngx_http_lua_socket_udp_upstream_destroy(lua_State *L)
+{
+    ngx_http_lua_socket_udp_upstream_t      *u;
+
+    dd("upstream destroy triggered by Lua GC");
+
+    u = lua_touserdata(L, 1);
+    if (u == NULL) {
+        return 0;
+    }
+
+    if (u->cleanup) {
+        ngx_http_lua_socket_udp_cleanup(u); /* it will clear u->cleanup */
+    }
+
+    return 0;
+}
+
+
+static void
+ngx_http_lua_socket_dummy_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u)
+{
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket dummy handler");
+}
+
+
+static ngx_int_t
+ngx_http_lua_socket_udp_read(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u)
+{
+    ngx_connection_t            *c;
+    ngx_event_t                 *rev;
+    ssize_t                      n;
+
+    c = u->udp_connection.connection;
+    rev = c->read;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "lua udp socket read data: waiting: %d", (int) u->waiting);
+
+    n = ngx_udp_recv(u->udp_connection.connection,
+                     ngx_http_lua_socket_udp_buffer, u->recv_buf_size);
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "lua udp recv returned %z", n);
+
+    if (n >= 0) {
+        u->received = n;
+        ngx_http_lua_socket_udp_handle_success(r, u);
+        return NGX_OK;
+    }
+
+    if (n == NGX_ERROR) {
+        u->socket_errno = ngx_socket_errno;
+        ngx_http_lua_socket_udp_handle_error(r, u,
+                                             NGX_HTTP_LUA_SOCKET_FT_ERROR);
+        return NGX_ERROR;
+    }
+
+    /* n == NGX_AGAIN */
+
+#if 1
+    if (ngx_handle_read_event(rev, 0) != NGX_OK) {
+        ngx_http_lua_socket_udp_handle_error(r, u,
+                                             NGX_HTTP_LUA_SOCKET_FT_ERROR);
+        return NGX_ERROR;
+    }
+#endif
+
+    if (rev->active) {
+        ngx_add_timer(rev, u->read_timeout);
+
+    } else if (rev->timer_set) {
+        ngx_del_timer(rev);
+    }
+
+    return NGX_AGAIN;
+}
+
+
+static void
+ngx_http_lua_socket_udp_read_handler(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u)
+{
+    ngx_connection_t            *c;
+    ngx_http_lua_loc_conf_t     *llcf;
+
+    c = u->udp_connection.connection;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket read handler");
+
+    if (c->read->timedout) {
+        c->read->timedout = 0;
+
+        llcf = ngx_http_get_module_loc_conf(r, ngx_http_lua_module);
+
+        if (llcf->log_socket_errors) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "lua udp socket read timed out");
+        }
+
+        ngx_http_lua_socket_udp_handle_error(r, u,
+                                             NGX_HTTP_LUA_SOCKET_FT_TIMEOUT);
+        return;
+    }
+
+#if 1
+    if (c->read->timer_set) {
+        ngx_del_timer(c->read);
+    }
+#endif
+
+    (void) ngx_http_lua_socket_udp_read(r, u);
+}
+
+
+static void
+ngx_http_lua_socket_udp_handle_error(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u, ngx_uint_t ft_type)
+{
+    ngx_http_lua_ctx_t          *ctx;
+    ngx_http_lua_co_ctx_t       *coctx;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket handle error");
+
+    u->ft_type |= ft_type;
+
+#if 0
+    ngx_http_lua_socket_udp_finalize(r, u);
+#endif
+
+    u->read_event_handler = ngx_http_lua_socket_dummy_handler;
+
+    coctx = u->co_ctx;
+
+    if (coctx) {
+        coctx->cleanup = NULL;
+    }
+
+    if (u->waiting) {
+        u->waiting = 0;
+
+        ctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);
+        if (ctx == NULL) {
+            return;
+        }
+
+        ctx->resume_handler = ngx_http_lua_socket_udp_resume;
+        ctx->cur_co_ctx = coctx;
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "lua udp socket waking up the current request");
+
+        r->write_event_handler(r);
+    }
+}
+
+
+static void
+ngx_http_lua_socket_udp_cleanup(void *data)
+{
+    ngx_http_lua_socket_udp_upstream_t  *u = data;
+
+    ngx_http_request_t  *r;
+
+    r = u->request;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "cleanup lua udp socket upstream request: \"%V\"", &r->uri);
+
+    ngx_http_lua_socket_udp_finalize(r, u);
+}
+
+
+static void
+ngx_http_lua_socket_udp_handler(ngx_event_t *ev)
+{
+    ngx_connection_t                *c;
+    ngx_http_request_t              *r;
+    ngx_http_log_ctx_t              *ctx;
+
+    ngx_http_lua_socket_udp_upstream_t  *u;
+
+    c = ev->data;
+    u = c->data;
+    r = u->request;
+    c = r->connection;
+
+    if (c->fd != (ngx_socket_t) -1) {  /* not a fake connection */
+        ctx = c->log->data;
+        ctx->current_request = r;
+    }
+
+    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "lua udp socket handler for \"%V?%V\", wev %d", &r->uri,
+                   &r->args, (int) ev->write);
+
+    u->read_event_handler(r, u);
+
+    ngx_http_run_posted_requests(c);
+}
+
+
+static void
+ngx_http_lua_socket_udp_handle_success(ngx_http_request_t *r,
+    ngx_http_lua_socket_udp_upstream_t *u)
+{
+    ngx_http_lua_ctx_t          *ctx;
+
+    u->read_event_handler = ngx_http_lua_socket_dummy_handler;
+
+    if (u->co_ctx) {
+        u->co_ctx->cleanup = NULL;
+    }
+
+    if (u->waiting) {
+        u->waiting = 0;
+
+        ctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);
+        if (ctx == NULL) {
+            return;
+        }
+
+        ctx->resume_handler = ngx_http_lua_socket_udp_resume;
+        ctx->cur_co_ctx = u->co_ctx;
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "lua udp socket waking up the current request");
+
+        r->write_event_handler(r);
+    }
+}
+
+
+static ngx_int_t
+ngx_http_lua_udp_connect(ngx_http_lua_udp_connection_t *uc, ngx_addr_t *local)
+{
+    int                rc;
+    ngx_int_t          event;
+    ngx_event_t       *rev, *wev;
+    ngx_socket_t       s;
+    ngx_connection_t  *c;
+
+    s = ngx_socket(uc->sockaddr->sa_family, SOCK_DGRAM, 0);
+
+    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, &uc->log, 0, "UDP socket %d", s);
+
+    if (s == (ngx_socket_t) -1) {
+        ngx_log_error(NGX_LOG_ALERT, &uc->log, ngx_socket_errno,
+                      ngx_socket_n " failed");
+
+        return NGX_ERROR;
+    }
+
+    c = ngx_get_connection(s, &uc->log);
+
+    if (c == NULL) {
+        if (ngx_close_socket(s) == -1) {
+            ngx_log_error(NGX_LOG_ALERT, &uc->log, ngx_socket_errno,
+                          ngx_close_socket_n "failed");
+        }
+
+        return NGX_ERROR;
+    }
+
+    if (ngx_nonblocking(s) == -1) {
+        ngx_log_error(NGX_LOG_ALERT, &uc->log, ngx_socket_errno,
+                      ngx_nonblocking_n " failed");
+
+        ngx_free_connection(c);
+
+        if (ngx_close_socket(s) == -1) {
+            ngx_log_error(NGX_LOG_ALERT, &uc->log, ngx_socket_errno,
+                          ngx_close_socket_n " failed");
+        }
+
+        return NGX_ERROR;
+    }
+
+    rev = c->read;
+    wev = c->write;
+
+    rev->log = &uc->log;
+    wev->log = &uc->log;
+
+    uc->connection = c;
+
+    c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1);
+
+#if (NGX_HTTP_LUA_HAVE_SO_PASSCRED)
+    if (uc->sockaddr->sa_family == AF_UNIX) {
+        struct sockaddr         addr;
+
+        addr.sa_family = AF_UNIX;
+
+        /* just to make valgrind happy */
+        ngx_memzero(addr.sa_data, sizeof(addr.sa_data));
+
+        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, &uc->log, 0, "datagram unix "
+                       "domain socket autobind");
+
+        if (bind(uc->connection->fd, &addr, sizeof(sa_family_t)) != 0) {
+            ngx_log_error(NGX_LOG_CRIT, &uc->log, ngx_socket_errno,
+                          "bind() failed");
+
+            return NGX_ERROR;
+        }
+    }
+
+#endif
+
+    if (local != NULL) {
+        fprintf(stderr, "=== have local address\n");
+        if (bind(s, local->sockaddr, local->socklen) == -1) {
+            ngx_log_error(NGX_LOG_CRIT, &uc->log, ngx_socket_errno,
+                          "bind(%V) failed", &local->name);
+
+            return NGX_ERROR;
+        }
+    }
+
+    ngx_log_debug3(NGX_LOG_DEBUG_EVENT, &uc->log, 0,
+                   "connect to %V, fd:%d #%d", &uc->server, s, c->number);
+
+    rc = connect(s, uc->sockaddr, uc->socklen);
+
+    /* TODO: aio, iocp */
+
+    if (rc == -1) {
+        ngx_log_error(NGX_LOG_CRIT, &uc->log, ngx_socket_errno,
+                      "connect() failed");
+
+        return NGX_ERROR;
+    }
+
+    /* UDP sockets are always ready to write */
+    wev->ready = 1;
+
+    if (ngx_add_event) {
+
+        event = (ngx_event_flags & NGX_USE_CLEAR_EVENT) ?
+                    /* kqueue, epoll */                 NGX_CLEAR_EVENT:
+                    /* select, poll, /dev/poll */       NGX_LEVEL_EVENT;
+                    /* eventport event type has no meaning: oneshot only */
+
+        if (ngx_add_event(rev, NGX_READ_EVENT, event) != NGX_OK) {
+            return NGX_ERROR;
+        }
+
+    } else {
+        /* rtsig */
+
+        if (ngx_add_conn(c) == NGX_ERROR) {
+            return NGX_ERROR;
+        }
+    }
+
+    return NGX_OK;
+}
+
+
+static int
+ngx_http_lua_socket_udp_close(lua_State *L)
+{
+    ngx_http_request_t                  *r;
+    ngx_http_lua_socket_udp_upstream_t  *u;
+
+    if (lua_gettop(L) != 1) {
+        return luaL_error(L, "expecting 1 argument "
+                          "(including the object) but seen %d", lua_gettop(L));
+    }
+
+    r = ngx_http_lua_get_req(L);
+    if (r == NULL) {
+        return luaL_error(L, "no request found");
+    }
+
+    luaL_checktype(L, 1, LUA_TTABLE);
+
+    lua_rawgeti(L, 1, SOCKET_CTX_INDEX);
+    u = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+
+    if (u == NULL || u->udp_connection.connection == NULL) {
+        lua_pushnil(L);
+        lua_pushliteral(L, "closed");
+        return 2;
+    }
+
+    if (u->request != r) {
+        return luaL_error(L, "bad request");
+    }
+
+    if (u->waiting) {
+        lua_pushnil(L);
+        lua_pushliteral(L, "socket busy");
+        return 2;
+    }
+
+    ngx_http_lua_socket_udp_finalize(r, u);
+
+    lua_pushinteger(L, 1);
+    return 1;
+}
+
+
+static ngx_int_t
+ngx_http_lua_socket_udp_resume(ngx_http_request_t *r)
+{
+    int                          nret;
+    lua_State                   *vm;
+    ngx_int_t                    rc;
+    ngx_uint_t                   nreqs;
+    ngx_connection_t            *c;
+    ngx_http_lua_ctx_t          *ctx;
+    ngx_http_lua_co_ctx_t       *coctx;
+
+    ngx_http_lua_socket_udp_upstream_t      *u;
+
+    ctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);
+    if (ctx == NULL) {
+        return NGX_ERROR;
+    }
+
+    ctx->resume_handler = ngx_http_lua_wev_handler;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp operation done, resuming lua thread");
+
+    coctx = ctx->cur_co_ctx;
+
+#if 0
+    ngx_http_lua_probe_info("udp resume");
+#endif
+
+    u = coctx->data;
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua udp socket calling prepare retvals handler %p, "
+                   "u:%p", u->prepare_retvals, u);
+
+    nret = u->prepare_retvals(r, u, ctx->cur_co_ctx->co);
+    if (nret == NGX_AGAIN) {
+        return NGX_DONE;
+    }
+
+    c = r->connection;
+    vm = ngx_http_lua_get_lua_vm(r, ctx);
+    nreqs = c->requests;
+
+    rc = ngx_http_lua_run_thread(vm, r, ctx, nret);
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "lua run thread returned %d", rc);
+
+    if (rc == NGX_AGAIN) {
+        return ngx_http_lua_run_posted_threads(c, vm, r, ctx, nreqs);
+    }
+
+    if (rc == NGX_DONE) {
+        ngx_http_lua_finalize_request(r, NGX_DONE);
+        return ngx_http_lua_run_posted_threads(c, vm, r, ctx, nreqs);
+    }
+
+    if (ctx->entered_content_phase) {
+        ngx_http_lua_finalize_request(r, rc);
+        return NGX_DONE;
+    }
+
+    return rc;
+}
+
+
+static void
+ngx_http_lua_udp_resolve_cleanup(void *data)
+{
+    ngx_resolver_ctx_t                      *rctx;
+    ngx_http_lua_socket_udp_upstream_t      *u;
+    ngx_http_lua_co_ctx_t                   *coctx = data;
+
+    u = coctx->data;
+    if (u == NULL) {
+        return;
+    }
+
+    rctx = u->resolved->ctx;
+    if (rctx == NULL) {
+        return;
+    }
+
+    /* postpone free the rctx in the handler */
+    rctx->handler = ngx_resolve_name_done;
+}
+
+
+static void
+ngx_http_lua_udp_socket_cleanup(void *data)
+{
+    ngx_http_lua_socket_udp_upstream_t      *u;
+    ngx_http_lua_co_ctx_t                   *coctx = data;
+
+    u = coctx->data;
+    if (u == NULL) {
+        return;
+    }
+
+    if (u->request == NULL) {
+        return;
+    }
+
+    ngx_http_lua_socket_udp_finalize(u->request, u);
+}
+
+/* vi:set ft=c ts=4 sw=4 et fdm=marker: */