diff options
Diffstat (limited to 'common.c')
| -rw-r--r-- | common.c | 233 |
1 files changed, 233 insertions, 0 deletions
@@ -90,6 +90,239 @@ log_message_syslog (void *user_data, const char *quote, const char *fmt, syslog (prio, "%s%s", quote, buf); } +// --- Connector --------------------------------------------------------------- + +// This is a helper that tries to establish a connection with any address on +// a given list. Sadly it also introduces a bit of a callback hell. + +struct connector_target +{ + LIST_HEADER (struct connector_target) + + char *hostname; ///< Target hostname or address + char *service; ///< Target service name or port + + struct addrinfo *results; ///< Resolved target + struct addrinfo *iter; ///< Current endpoint +}; + +static struct connector_target * +connector_target_new (void) +{ + struct connector_target *self = xmalloc (sizeof *self); + return self; +} + +static void +connector_target_destroy (struct connector_target *self) +{ + free (self->hostname); + free (self->service); + freeaddrinfo (self->results); + free (self); +} + +// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + +struct connector +{ + int socket; ///< Socket FD for the connection + struct poller_fd connected_event; ///< We've connected or failed + struct connector_target *targets; ///< Targets + struct connector_target *targets_t; ///< Tail of targets + + void *user_data; ///< User data for callbacks + + // You may destroy the connector object in these two main callbacks: + + /// Connection has been successfully established + void (*on_connected) (void *user_data, int socket); + /// Failed to establish a connection to either target + void (*on_failure) (void *user_data); + + // Optional: + + /// Connecting to a new address + void (*on_connecting) (void *user_data, const char *address); + /// Connecting to the last address has failed + void (*on_error) (void *user_data, const char *error); +}; + +static void +connector_notify_connecting (struct connector *self, + struct connector_target *target, struct addrinfo *gai_iter) +{ + if (!self->on_connecting) + return; + + const char *real_host = target->hostname; + + // We don't really need this, so we can let it quietly fail + char buf[NI_MAXHOST]; + int err = getnameinfo (gai_iter->ai_addr, gai_iter->ai_addrlen, + buf, sizeof buf, NULL, 0, NI_NUMERICHOST); + if (err) + LOG_FUNC_FAILURE ("getnameinfo", gai_strerror (err)); + else + real_host = buf; + + char *address = format_host_port_pair (real_host, target->service); + self->on_connecting (self->user_data, address); + free (address); +} + +static void +connector_notify_error (struct connector *self, const char *error) +{ + if (self->on_error) + self->on_error (self->user_data, error); +} + +static void +connector_prepare_next (struct connector *self) +{ + struct connector_target *target = self->targets; + if (!(target->iter = target->iter->ai_next)) + { + LIST_UNLINK_WITH_TAIL (self->targets, self->targets_t, target); + connector_target_destroy (target); + } +} + +static void +connector_step (struct connector *self) +{ + struct connector_target *target = self->targets; + if (!target) + { + // Total failure, none of the targets has succeeded + self->on_failure (self->user_data); + return; + } + + struct addrinfo *gai_iter = target->iter; + hard_assert (gai_iter != NULL); + + connector_notify_connecting (self, target, gai_iter); + + int fd = self->socket = socket (gai_iter->ai_family, + gai_iter->ai_socktype, gai_iter->ai_protocol); + if (fd == -1) + { + connector_notify_error (self, strerror (errno)); + + connector_prepare_next (self); + connector_step (self); + return; + } + + set_cloexec (fd); + set_blocking (fd, false); + + int yes = 1; + soft_assert (setsockopt (fd, SOL_SOCKET, SO_KEEPALIVE, + &yes, sizeof yes) != -1); + + if (!connect (fd, gai_iter->ai_addr, gai_iter->ai_addrlen)) + { + set_blocking (fd, true); + self->on_connected (self->user_data, fd); + return; + } + else if (errno != EINPROGRESS) + { + connector_notify_error (self, strerror (errno)); + xclose (fd); + + connector_prepare_next (self); + connector_step (self); + return; + } + + self->connected_event.fd = self->socket = fd; + poller_fd_set (&self->connected_event, POLLOUT); + + connector_prepare_next (self); +} + +static void +connector_on_ready (const struct pollfd *pfd, struct connector *self) +{ + // See http://cr.yp.to/docs/connect.html if this doesn't work. + // The second connect() method doesn't work with DragonflyBSD. + + int error = 0; + socklen_t error_len = sizeof error; + hard_assert (!getsockopt (pfd->fd, + SOL_SOCKET, SO_ERROR, &error, &error_len)); + + if (error) + { + connector_notify_error (self, strerror (errno)); + + xclose (self->socket); + self->socket = -1; + + connector_step (self); + } + else + { + poller_fd_reset (&self->connected_event); + self->socket = -1; + + set_blocking (pfd->fd, true); + self->on_connected (self->user_data, pfd->fd); + } +} + +static void +connector_init (struct connector *self, struct poller *poller) +{ + memset (self, 0, sizeof *self); + self->socket = -1; + poller_fd_init (&self->connected_event, poller, self->socket); + self->connected_event.user_data = self; + self->connected_event.dispatcher = (poller_fd_fn) connector_on_ready; +} + +static void +connector_free (struct connector *self) +{ + poller_fd_reset (&self->connected_event); + if (self->socket != -1) + xclose (self->socket); + + LIST_FOR_EACH (struct connector_target, iter, self->targets) + connector_target_destroy (iter); +} + +static bool +connector_add_target (struct connector *self, + const char *hostname, const char *service, struct error **e) +{ + struct addrinfo hints, *results; + memset (&hints, 0, sizeof hints); + hints.ai_socktype = SOCK_STREAM; + + // TODO: even this should be done asynchronously, most likely in + // a thread pool, similarly to how libuv does it + int err = getaddrinfo (hostname, service, &hints, &results); + if (err) + { + error_set (e, "%s: %s", "getaddrinfo", gai_strerror (err)); + return false; + } + + struct connector_target *target = connector_target_new (); + target->hostname = xstrdup (hostname); + target->service = xstrdup (service); + target->results = results; + target->iter = target->results; + + LIST_APPEND_WITH_TAIL (self->targets, self->targets_t, target); + return true; +} + // --- SOCKS 5/4a (blocking implementation) ------------------------------------ // These are awkward protocols. Note that the `username' is used differently |