+#ifdef FEATURE_CONNECTION_KEEP_ALIVE
+
+#define MAX_REUSABLE_CONNECTIONS 100
+
+struct reusable_connection
+{
+ jb_socket sfd;
+ int in_use;
+ char *host;
+ int port;
+
+ int forwarder_type;
+ char *gateway_host;
+ int gateway_port;
+ char *forward_host;
+ int forward_port;
+};
+
+static struct reusable_connection reusable_connection[MAX_REUSABLE_CONNECTIONS];
+
+static int mark_connection_unused(jb_socket sfd);
+static void mark_connection_closed(struct reusable_connection *closed_connection);
+
+/*********************************************************************
+ *
+ * Function : initialize_reusable_connections
+ *
+ * Description : Initializes the reusable_connection structures.
+ * Must be called with connection_reuse_mutex locked.
+ *
+ * Parameters : N/A
+ *
+ * Returns : void
+ *
+ *********************************************************************/
+extern void initialize_reusable_connections(void)
+{
+ unsigned int slot = 0;
+
+ log_error(LOG_LEVEL_INFO,
+ "Support for 'Connection: keep-alive' is experimental, "
+ "incomplete and known not to work properly in some situations.");
+
+ for (slot = 0; slot < SZ(reusable_connection); slot++)
+ {
+ mark_connection_closed(&reusable_connection[slot]);
+ }
+
+ log_error(LOG_LEVEL_CONNECT, "Initialized %d socket slots.", slot);
+}
+
+
+/*********************************************************************
+ *
+ * Function : remember_connection
+ *
+ * Description : Remembers a connection for reuse later on.
+ *
+ * Parameters :
+ * 1 : sfd = Open socket to remember.
+ * 2 : http = The destination for the connection.
+ * 3 : fwd = The forwarder settings used.
+ *
+ * Returns : void
+ *
+ *********************************************************************/
+void remember_connection(jb_socket sfd, const struct http_request *http,
+ const struct forward_spec *fwd)
+{
+ unsigned int slot = 0;
+ int free_slot_found = FALSE;
+
+ assert(sfd != JB_INVALID_SOCKET);
+
+ if (mark_connection_unused(sfd))
+ {
+ return;
+ }
+
+ privoxy_mutex_lock(&connection_reuse_mutex);
+
+ /* Find free socket slot. */
+ for (slot = 0; slot < SZ(reusable_connection); slot++)
+ {
+ if (reusable_connection[slot].sfd == JB_INVALID_SOCKET)
+ {
+ assert(reusable_connection[slot].in_use == 0);
+ log_error(LOG_LEVEL_CONNECT,
+ "Remembering socket %d for %s:%d in slot %d.",
+ sfd, http->host, http->port, slot);
+ free_slot_found = TRUE;
+ break;
+ }
+ }
+
+ if (!free_slot_found)
+ {
+ log_error(LOG_LEVEL_CONNECT,
+ "No free slots found to remembering socket for %s:%d. Last slot %d.",
+ http->host, http->port, slot);
+ privoxy_mutex_unlock(&connection_reuse_mutex);
+ close_socket(sfd);
+ return;
+ }
+
+ assert(NULL != http->host);
+ reusable_connection[slot].host = strdup(http->host);
+ if (NULL == reusable_connection[slot].host)
+ {
+ log_error(LOG_LEVEL_FATAL, "Out of memory saving socket.");
+ }
+ reusable_connection[slot].sfd = sfd;
+ reusable_connection[slot].port = http->port;
+ reusable_connection[slot].in_use = 0;
+
+ assert(NULL != fwd);
+ assert(reusable_connection[slot].gateway_host == NULL);
+ assert(reusable_connection[slot].gateway_port == 0);
+ assert(reusable_connection[slot].forwarder_type == SOCKS_NONE);
+ assert(reusable_connection[slot].forward_host == NULL);
+ assert(reusable_connection[slot].forward_port == 0);
+
+ reusable_connection[slot].forwarder_type = fwd->type;
+ if (NULL != fwd->gateway_host)
+ {
+ reusable_connection[slot].gateway_host = strdup(fwd->gateway_host);
+ if (NULL == reusable_connection[slot].gateway_host)
+ {
+ log_error(LOG_LEVEL_FATAL, "Out of memory saving gateway_host.");
+ }
+ }
+ else
+ {
+ reusable_connection[slot].gateway_host = NULL;
+ }
+ reusable_connection[slot].gateway_port = fwd->gateway_port;
+
+ if (NULL != fwd->forward_host)
+ {
+ reusable_connection[slot].forward_host = strdup(fwd->forward_host);
+ if (NULL == reusable_connection[slot].forward_host)
+ {
+ log_error(LOG_LEVEL_FATAL, "Out of memory saving forward_host.");
+ }
+ }
+ else
+ {
+ reusable_connection[slot].forward_host = NULL;
+ }
+ reusable_connection[slot].forward_port = fwd->forward_port;
+
+ privoxy_mutex_unlock(&connection_reuse_mutex);
+}
+
+
+/*********************************************************************
+ *
+ * Function : mark_connection_closed
+ *
+ * Description : Marks a reused connection closed.
+ * Must be called with connection_reuse_mutex locked.
+ *
+ * Parameters :
+ * 1 : closed_connection = The connection to mark as closed.
+ *
+ * Returns : void
+ *
+ *********************************************************************/
+static void mark_connection_closed(struct reusable_connection *closed_connection)
+{
+ closed_connection->in_use = FALSE;
+ closed_connection->sfd = JB_INVALID_SOCKET;
+ freez(closed_connection->host);
+ closed_connection->port = 0;
+ closed_connection->forwarder_type = SOCKS_NONE;
+ freez(closed_connection->gateway_host);
+ closed_connection->gateway_port = 0;
+ freez(closed_connection->forward_host);
+ closed_connection->forward_port = 0;
+}
+
+
+/*********************************************************************
+ *
+ * Function : forget_connection
+ *
+ * Description : Removes a previously remembered connection from
+ * the list of reusable connections.
+ *
+ * Parameters :
+ * 1 : sfd = The socket belonging to the connection in question.
+ *
+ * Returns : void
+ *
+ *********************************************************************/
+void forget_connection(jb_socket sfd)
+{
+ unsigned int slot = 0;
+
+ assert(sfd != JB_INVALID_SOCKET);
+
+ privoxy_mutex_lock(&connection_reuse_mutex);
+
+ for (slot = 0; slot < SZ(reusable_connection); slot++)
+ {
+ if (reusable_connection[slot].sfd == sfd)
+ {
+ assert(reusable_connection[slot].in_use);
+ break;
+ }
+ }
+
+ if (reusable_connection[slot].sfd != sfd)
+ {
+ log_error(LOG_LEVEL_CONNECT,
+ "Socket %d already forgotten or never remembered.", sfd);
+ privoxy_mutex_unlock(&connection_reuse_mutex);
+ return;
+ }
+
+ log_error(LOG_LEVEL_CONNECT,
+ "Forgetting socket %d for %s:%d in slot %d.",
+ sfd, reusable_connection[slot].host, reusable_connection[slot].port, slot);
+
+ mark_connection_closed(&reusable_connection[slot]);
+
+ privoxy_mutex_unlock(&connection_reuse_mutex);
+}
+
+
+/*********************************************************************
+ *
+ * Function : connection_destination_matches
+ *
+ * Description : Determines whether a remembered connection can
+ * be reused. That is whether the destination and
+ * the forwarding settings match.
+ *
+ * Parameters :
+ * 1 : connection = The connection to check.
+ * 2 : http = The destination for the connection.
+ * 3 : fwd = The forwarder settings.
+ *
+ * Returns : TRUE for yes, FALSE otherwise.
+ *
+ *********************************************************************/
+static int connection_destination_matches(const struct reusable_connection *connection,
+ const struct http_request *http,
+ const struct forward_spec *fwd)
+{
+ /* XXX: Start of duplicated checks for debugging purposes. */
+ if (strcmpic(connection->host, http->host))
+ {
+ return FALSE;
+ }
+
+ if (connection->forwarder_type != fwd->type)
+ {
+ log_error(LOG_LEVEL_CONNECT, "Type mismatch: %d %d (%s)",
+ connection->forwarder_type, fwd->type, http->host);
+ return FALSE;
+ }
+ if (connection->gateway_port != fwd->gateway_port)
+ {
+ log_error(LOG_LEVEL_CONNECT, "Gateway port mismatch: %d %d (%s)",
+ connection->gateway_port, fwd->gateway_port, http->host);
+ return FALSE;
+ }
+ if (connection->forward_port != fwd->forward_port)
+ {
+ log_error(LOG_LEVEL_CONNECT, "Forward port mismatch: %d %d (%s)",
+ connection->forward_port, fwd->forward_port, http->host);
+ return FALSE;
+ }
+ if (connection->forward_port != fwd->forward_port)
+ {
+ log_error(LOG_LEVEL_CONNECT, "Server port mismatch: %d %d (%s)",
+ connection->forward_port, fwd->forward_port, http->host);
+ return FALSE;
+ }
+
+ /* XXX: End of duplicated checks for debugging purposes. */
+
+ if ((connection->forwarder_type != fwd->type)
+ || (connection->gateway_port != fwd->gateway_port)
+ || (connection->forward_port != fwd->forward_port)
+ || (connection->port != http->port))
+ {
+ return FALSE;
+ }
+
+ if (( (NULL != connection->gateway_host)
+ && (NULL != fwd->gateway_host)
+ && strcmpic(connection->gateway_host, fwd->gateway_host))
+ && (connection->gateway_host != fwd->gateway_host))
+ {
+ log_error(LOG_LEVEL_CONNECT, "Gateway mismatch.");
+ return FALSE;
+ }
+
+ if (( (NULL != connection->forward_host)
+ && (NULL != fwd->forward_host)
+ && strcmpic(connection->forward_host, fwd->forward_host))
+ && (connection->forward_host != fwd->forward_host))
+ {
+ log_error(LOG_LEVEL_CONNECT, "Forwarding proxy mismatch.");
+ return FALSE;
+ }
+
+ return (!strcmpic(connection->host, http->host));
+
+}
+
+/*********************************************************************
+ *
+ * Function : get_reusable_connection
+ *
+ * Description : Returns an open socket to a previously remembered
+ * open connection (if there is one).
+ *
+ * Parameters :
+ * 1 : http = The destination for the connection.
+ * 2 : fwd = The forwarder settings.
+ *
+ * Returns : JB_INVALID_SOCKET => No reusable connection found,
+ * otherwise a usable socket.
+ *
+ *********************************************************************/
+static jb_socket get_reusable_connection(const struct http_request *http,
+ const struct forward_spec *fwd)
+{
+ jb_socket sfd = JB_INVALID_SOCKET;
+ unsigned int slot = 0;
+
+ privoxy_mutex_lock(&connection_reuse_mutex);
+
+ for (slot = 0; slot < SZ(reusable_connection); slot++)
+ {
+ if (!reusable_connection[slot].in_use
+ && (JB_INVALID_SOCKET != reusable_connection[slot].sfd))
+ {
+ int poll_result;
+ struct pollfd poll_fd[1];
+ memset(poll_fd, 0, sizeof(poll_fd));
+ poll_fd[0].fd = reusable_connection[slot].sfd;
+ poll_fd[0].events = POLLIN;
+
+ poll_result = poll(poll_fd, 1, 0);
+
+ if (-1 != poll_result)
+ {
+ if ((poll_fd[0].revents & POLLIN))
+ {
+ log_error(LOG_LEVEL_CONNECT,
+ "Socket %d for %s:%d in slot %d is no longer usable. Closing.",
+ reusable_connection[slot].sfd, reusable_connection[slot].host,
+ reusable_connection[slot].port, slot);
+ mark_connection_closed(&reusable_connection[slot]);
+ }
+ }
+ else
+ {
+ log_error(LOG_LEVEL_CONNECT,
+ "Failed to poll socket %d for %s:%d in slot %d",
+ reusable_connection[slot].sfd, reusable_connection[slot].host,
+ reusable_connection[slot].port, slot);
+ }
+
+
+ if (connection_destination_matches(&reusable_connection[slot], http, fwd))
+ {
+ reusable_connection[slot].in_use = TRUE;
+ sfd = reusable_connection[slot].sfd;
+ log_error(LOG_LEVEL_CONNECT,
+ "Found reusable socket %d for %s:%d in slot %d",
+ sfd, reusable_connection[slot].host, reusable_connection[slot].port, slot);
+ break;
+ }
+ }
+ }
+
+ privoxy_mutex_unlock(&connection_reuse_mutex);
+
+ return sfd;
+
+}
+
+
+/*********************************************************************
+ *
+ * Function : mark_connection_unused
+ *
+ * Description : Gives a remembered connection free for reuse.
+ *
+ * Parameters :
+ * 1 : sfd = The socket belonging to the connection in question.
+ *
+ * Returns : TRUE => Socket found and marked as unused.
+ * FALSE => Socket not found.
+ *
+ *********************************************************************/
+static int mark_connection_unused(jb_socket sfd)
+{
+ unsigned int slot = 0;
+ unsigned int socket_found = FALSE;
+
+ assert(sfd != JB_INVALID_SOCKET);
+
+ privoxy_mutex_lock(&connection_reuse_mutex);
+
+ for (slot = 0; slot < SZ(reusable_connection); slot++)
+ {
+ if (reusable_connection[slot].sfd == sfd)
+ {
+ assert(reusable_connection[slot].in_use);
+ break;
+ }
+ }
+
+ if (reusable_connection[slot].sfd == sfd)
+ {
+ socket_found = TRUE;
+ log_error(LOG_LEVEL_CONNECT,
+ "Marking open socket %d for %s:%d in slot %d as unused.",
+ sfd, reusable_connection[slot].host, reusable_connection[slot].port, slot);
+ reusable_connection[slot].in_use = 0;
+ }
+
+ privoxy_mutex_unlock(&connection_reuse_mutex);
+
+ return socket_found;
+
+}
+#endif /* def FEATURE_CONNECTION_KEEP_ALIVE */
+