shrpx: Add non-TLS SPDY backend connection support

Use --backend-spdy-no-tls to disable TLS on backend SPDY connection.
The SPDY protocol used there must be configured by
--backend-spdy-proto option.

src/shrpx.cc

@@ -240,10 +240,12 @@ int event_loop()
 
   if(get_config()->client_mode) {
     sv_ssl_ctx = 0;
-    cl_ssl_ctx = ssl::create_ssl_client_context();
+    cl_ssl_ctx = get_config()->spdy_downstream_no_tls ?
+      0 : ssl::create_ssl_client_context();
   } else {
     sv_ssl_ctx = get_config()->default_ssl_ctx;
-    cl_ssl_ctx = get_config()->spdy_bridge ?
+    cl_ssl_ctx = get_config()->spdy_bridge &&
+      !get_config()->spdy_downstream_no_tls ?
       ssl::create_ssl_client_context() : 0;
   }
 
@@ -271,7 +273,7 @@ int event_loop()
 
   if(get_config()->num_worker > 1) {
     listener_handler->create_worker_thread(get_config()->num_worker);
-  } else if(cl_ssl_ctx) {
+  } else if(get_config()->downstream_proto == PROTO_SPDY) {
     listener_handler->create_spdy_session();
   }
 
@@ -354,6 +356,9 @@ void fill_default_config()
   mod_config()->spdy_upstream_window_bits = 16;
   mod_config()->spdy_downstream_window_bits = 16;
 
+  mod_config()->spdy_downstream_no_tls = false;
+  mod_config()->spdy_downstream_version = 3;
+
   set_config_str(&mod_config()->downstream_host, "127.0.0.1");
   mod_config()->downstream_port = 80;
   mod_config()->downstream_hostport = 0;
@@ -530,6 +535,15 @@ void print_help(std::ostream& out)
       << "                       backend connection to 2**<N>.\n"
       << "                       Default: "
       << get_config()->spdy_downstream_window_bits << "\n"
+      << "    --backend-spdy-no-tls\n"
+      << "                       Disable SSL/TLS on backend SPDY connections.\n"
+      << "                       SPDY protocol must be specified using\n"
+      << "                       --backend-spdy-proto\n"
+      << "    --backend-spdy-proto\n"
+      << "                       Specify SPDY protocol used in backend\n"
+      << "                       connection if --backend-spdy-no-tls is used.\n"
+      << "                       Default: spdy/"
+      << get_config()->spdy_downstream_version << "\n"
       << "\n"
       << "  Mode:\n"
       << "    -s, --spdy-proxy   Enable secure SPDY proxy mode.\n"
@@ -628,6 +642,8 @@ int main(int argc, char **argv)
       {"subcert", required_argument, &flag, 24},
       {"spdy-bridge", no_argument, &flag, 25},
       {"backend-http-proxy-uri", required_argument, &flag, 26},
+      {"backend-spdy-no-tls", no_argument, &flag, 27},
+      {"backend-spdy-proto", required_argument, &flag, 28},
       {0, 0, 0, 0 }
     };
     int option_index = 0;
@@ -787,6 +803,16 @@ int main(int argc, char **argv)
         cmdcfgs.push_back(std::make_pair(SHRPX_OPT_BACKEND_HTTP_PROXY_URI,
                                          optarg));
         break;
+      case 27:
+        // --backend-spdy-no-tls
+        cmdcfgs.push_back(std::make_pair(SHRPX_OPT_BACKEND_SPDY_NO_TLS,
+                                         "yes"));
+        break;
+      case 28:
+        // --backend-spdy-proto
+        cmdcfgs.push_back(std::make_pair(SHRPX_OPT_BACKEND_SPDY_PROTO,
+                                         optarg));
+        break;
       default:
         break;
       }
@@ -842,6 +868,20 @@ int main(int argc, char **argv)
     mod_config()->client_mode = true;
   }
 
+  if(get_config()->client_mode || get_config()->spdy_bridge) {
+    mod_config()->downstream_proto = PROTO_SPDY;
+  } else {
+    mod_config()->downstream_proto = PROTO_HTTP;
+  }
+
+  if(mod_config()->downstream_proto == PROTO_SPDY &&
+     mod_config()->spdy_downstream_no_tls &&
+     mod_config()->spdy_downstream_version == 0) {
+    LOG(FATAL) << "--backend-spdy-no-tls: Specify backend SPDY protocol using"
+               << " --backend-spdy-proto";
+    exit(EXIT_FAILURE);
+  }
+
   if(!get_config()->client_mode) {
     if(!get_config()->private_key_file || !get_config()->cert_file) {
       print_usage(std::cerr);

src/shrpx_config.cc

@@ -36,6 +36,8 @@
 #include <limits>
 #include <fstream>
 
+#include <spdylay/spdylay.h>
+
 #include "shrpx_log.h"
 #include "shrpx_ssl.h"
 #include "shrpx_http.h"
@@ -73,6 +75,8 @@ const char
 SHRPX_OPT_BACKEND_KEEP_ALIVE_TIMEOUT[] = "backend-keep-alive-timeout";
 const char SHRPX_OPT_FRONTEND_SPDY_WINDOW_BITS[] = "frontend-spdy-window-bits";
 const char SHRPX_OPT_BACKEND_SPDY_WINDOW_BITS[] = "backend-spdy-window-bits";
+const char SHRPX_OPT_BACKEND_SPDY_NO_TLS[] = "backend-spdy-no-tls";
+const char SHRPX_OPT_BACKEND_SPDY_PROTO[] = "backend-spdy-proto";
 const char SHRPX_OPT_PID_FILE[] = "pid-file";
 const char SHRPX_OPT_USER[] = "user";
 const char SHRPX_OPT_SYSLOG[] = "syslog";
@@ -259,6 +263,18 @@ int parse_config(const char *opt, const char *optarg)
                  << " specify the integer in the range [0, 30], inclusive";
       return -1;
     }
+  } else if(util::strieq(opt, SHRPX_OPT_BACKEND_SPDY_NO_TLS)) {
+    mod_config()->spdy_downstream_no_tls = util::strieq(optarg, "yes");
+  } else if(util::strieq(opt, SHRPX_OPT_BACKEND_SPDY_PROTO)) {
+    size_t len = strlen(optarg);
+    const unsigned char *proto;
+    proto = reinterpret_cast<const unsigned char*>(optarg);
+    uint16_t version = spdylay_npn_get_version(proto, len);
+    if(!version) {
+      LOG(ERROR) << "Unsupported SPDY version: " << optarg;
+      return -1;
+    }
+    mod_config()->spdy_downstream_version = version;
   } else if(util::strieq(opt, SHRPX_OPT_PID_FILE)) {
     set_config_str(&mod_config()->pid_file, optarg);
   } else if(util::strieq(opt, SHRPX_OPT_USER)) {

src/shrpx_config.h

@@ -68,6 +68,8 @@ extern const char SHRPX_OPT_ACCESSLOG[];
 extern const char SHRPX_OPT_BACKEND_KEEP_ALIVE_TIMEOUT[];
 extern const char SHRPX_OPT_FRONTEND_SPDY_WINDOW_BITS[];
 extern const char SHRPX_OPT_BACKEND_SPDY_WINDOW_BITS[];
+extern const char SHRPX_OPT_BACKEND_SPDY_NO_TLS[];
+extern const char SHRPX_OPT_BACKEND_SPDY_PROTO[];
 extern const char SHRPX_OPT_PID_FILE[];
 extern const char SHRPX_OPT_USER[];
 extern const char SHRPX_OPT_SYSLOG[];
@@ -88,6 +90,11 @@ union sockaddr_union {
   sockaddr_in in;
 };
 
+enum shrpx_proto {
+  PROTO_SPDY,
+  PROTO_HTTP
+};
+
 struct Config {
   bool verbose;
   bool daemon;
@@ -121,6 +128,8 @@ struct Config {
   bool accesslog;
   size_t spdy_upstream_window_bits;
   size_t spdy_downstream_window_bits;
+  bool spdy_downstream_no_tls;
+  uint16_t spdy_downstream_version;
   char *pid_file;
   uid_t uid;
   gid_t gid;
@@ -134,6 +143,8 @@ struct Config {
   bool client;
   // true if --client or --client-proxy are enabled.
   bool client_mode;
+  // downstream protocol; this will be determined by given options.
+  shrpx_proto downstream_proto;
   bool insecure;
   char *cacert;
   bool backend_ipv4;

src/shrpx_spdy_session.cc

@@ -79,14 +79,18 @@ int SpdySession::disconnect()
   }
   if(bev_) {
     int fd = bufferevent_getfd(bev_);
-    if(fd != -1 && fd_ == -1) {
-      fd_ = fd;
-    } else if(fd != -1 && fd_ != -1) {
-      assert(fd == fd_);
-    }
     bufferevent_disable(bev_, EV_READ | EV_WRITE);
     bufferevent_free(bev_);
     bev_ = 0;
+    if(fd != -1) {
+      if(fd_ == -1) {
+        fd_ = fd;
+      } else if(fd != fd_) {
+        SSLOG(WARNING, this) << "fd in bev_ != fd_";
+        shutdown(fd, SHUT_WR);
+        close(fd);
+      }
+    }
   }
   if(ssl_) {
     SSL_free(ssl_);
@@ -94,6 +98,9 @@ int SpdySession::disconnect()
   ssl_ = 0;
 
   if(fd_ != -1) {
+    if(LOG_ENABLED(INFO)) {
+      SSLOG(INFO, this) << "Closing fd=" << fd_;
+    }
     shutdown(fd_, SHUT_WR);
     close(fd_);
     fd_ = -1;
@@ -241,7 +248,8 @@ void eventcb(bufferevent *bev, short events, void *ptr)
       SSLOG(INFO, spdy) << "Connection established";
     }
     spdy->set_state(SpdySession::CONNECTED);
-    if((!get_config()->insecure && spdy->check_cert() != 0) ||
+    if((!get_config()->spdy_downstream_no_tls &&
+        !get_config()->insecure && spdy->check_cert() != 0) ||
        spdy->on_connect() != 0) {
       spdy->disconnect();
       return;
@@ -282,7 +290,9 @@ void proxy_readcb(bufferevent *bev, void *ptr)
       // here. But we keep fd_ inside it.
       spdy->unwrap_free_bev();
       // Initiate SSL/TLS handshake through established tunnel.
-      spdy->initiate_connection();
+      if(spdy->initiate_connection() != 0) {
+        spdy->disconnect();
+      }
       break;
     case SpdySession::PROXY_FAILED:
       spdy->disconnect();
@@ -347,7 +357,7 @@ int SpdySession::check_cert()
 
 int SpdySession::initiate_connection()
 {
-  int rv;
+  int rv = 0;
   if(get_config()->downstream_http_proxy_host && state_ == DISCONNECTED) {
     if(LOG_ENABLED(INFO)) {
       SSLOG(INFO, this) << "Connecting to the proxy "
@@ -383,7 +393,8 @@ int SpdySession::initiate_connection()
     if(LOG_ENABLED(INFO)) {
       SSLOG(INFO, this) << "Connecting to downstream server";
     }
-
+    if(ssl_ctx_) {
+      // We are establishing TLS connection.
       ssl_ = SSL_new(ssl_ctx_);
       if(!ssl_) {
         SSLOG(ERROR, this) << "SSL_new() failed: "
@@ -407,6 +418,25 @@ int SpdySession::initiate_connection()
          // TODO maybe not thread-safe?
          const_cast<sockaddr*>(&get_config()->downstream_addr.sa),
          get_config()->downstream_addrlen);
+    } else if(state_ == DISCONNECTED) {
+      // Without TLS and proxy.
+      bev_ = bufferevent_socket_new(evbase_, -1, BEV_OPT_DEFER_CALLBACKS);
+      rv = bufferevent_socket_connect
+        (bev_,
+         const_cast<sockaddr*>(&get_config()->downstream_addr.sa),
+         get_config()->downstream_addrlen);
+    } else {
+      assert(state_ == PROXY_CONNECTED);
+      // Without TLS but with proxy.
+      bev_ = bufferevent_socket_new(evbase_, fd_, BEV_OPT_DEFER_CALLBACKS);
+      // Connection already established.
+      eventcb(bev_, BEV_EVENT_CONNECTED, this);
+      // eventcb() has no return value. Check state_ to whether it was
+      // failed or not.
+      if(state_ == DISCONNECTED) {
+        return -1;
+      }
+    }
     if(rv != 0) {
       bufferevent_free(bev_);
       bev_ = 0;
@@ -418,7 +448,10 @@ int SpdySession::initiate_connection()
     bufferevent_setcb(bev_, readcb, writecb, eventcb, this);
     // No timeout for SPDY session
 
+    // We have been already connected when no TLS and proxy is used.
+    if(state_ != CONNECTED) {
       state_ = CONNECTING;
+    }
   } else {
     // Unreachable
     DIE();
@@ -972,18 +1005,23 @@ void on_unknown_ctrl_recv_callback(spdylay_session *session,
 int SpdySession::on_connect()
 {
   int rv;
+  uint16_t version;
   const unsigned char *next_proto = 0;
   unsigned int next_proto_len;
+  if(ssl_ctx_) {
     SSL_get0_next_proto_negotiated(ssl_, &next_proto, &next_proto_len);
 
     if(LOG_ENABLED(INFO)) {
       std::string proto(next_proto, next_proto+next_proto_len);
       SSLOG(INFO, this) << "Negotiated next protocol: " << proto;
     }
-  uint16_t version = spdylay_npn_get_version(next_proto, next_proto_len);
+    version = spdylay_npn_get_version(next_proto, next_proto_len);
     if(!version) {
       return -1;
     }
+  } else {
+    version = get_config()->spdy_downstream_version;
+  }
   spdylay_session_callbacks callbacks;
   memset(&callbacks, 0, sizeof(callbacks));
   callbacks.send_callback = send_callback;

src/shrpx_spdy_session.h

@@ -111,8 +111,13 @@ public:
   };
 private:
   event_base *evbase_;
+  // NULL if no TLS is configured
   SSL_CTX *ssl_ctx_;
   SSL *ssl_;
+  // fd_ is used for proxy connection and no TLS connection. For
+  // direct or TLS connection, it may be -1 even after connection is
+  // established. Use bufferevent_getfd(bev_) to get file descriptor
+  // in these cases.
   int fd_;
   spdylay_session *session_;
   bufferevent *bev_;

src/shrpx_worker.cc

@@ -75,7 +75,7 @@ void Worker::run()
   bufferevent *bev = bufferevent_socket_new(evbase, fd_,
                                             BEV_OPT_DEFER_CALLBACKS);
   SpdySession *spdy = 0;
-  if(cl_ssl_ctx_) {
+  if(get_config()->downstream_proto == PROTO_SPDY) {
     spdy = new SpdySession(evbase, cl_ssl_ctx_);
     if(spdy->init_notification() == -1) {
       DIE();