From c34bb483cab1bffec6449c4363d5099114c5cbe5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C5=99emysl=20Janouch?= Date: Wed, 22 Jul 2015 00:34:27 +0200 Subject: [PATCH] SOCKS: finishing touches Making sure that I handle all corner cases appropriately. --- common.c | 80 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 48 insertions(+), 32 deletions(-) diff --git a/common.c b/common.c index 99b3b8e..de00445 100644 --- a/common.c +++ b/common.c @@ -383,23 +383,20 @@ struct socks_connector // Negotiation: + struct poller_timer timeout; ///< Timeout timer + int socket_fd; ///< Current socket file descriptor struct poller_fd socket_event; ///< Socket can be read from/written to struct str read_buffer; ///< Read buffer struct str write_buffer; ///< Write buffer - struct poller_timer timeout; ///< Timeout timer - - bool done; ///< We're connected + bool done; ///< Tunnel succesfully established uint8_t bound_address_len; ///< Length of domain name - struct socks_addr bound_address; ///< Bound address at the server - uint16_t bound_port; ///< Bound port at the server + size_t data_needed; ///< How much data "on_data" needs /// Process incoming data if there's enough of it available bool (*on_data) (struct socks_connector *, struct msg_unpacker *); - size_t data_needed; ///< How much data the callback needs - // Configuration: const char *hostname; ///< SOCKS server hostname @@ -413,6 +410,11 @@ struct socks_connector void *user_data; ///< User data for callbacks + // Additional results: + + struct socks_addr bound_address; ///< Bound address at the server + uint16_t bound_port; ///< Bound port at the server + // You may destroy the connector object in these two main callbacks: /// Connection has been successfully established @@ -429,6 +431,8 @@ struct socks_connector void (*on_error) (void *user_data, const char *error); }; +// I've tried to make the actual protocol handlers as simple as possible + #define SOCKS_FAIL(...) \ BLOCK_START \ char *error = xstrdup_printf (__VA_ARGS__); \ @@ -712,18 +716,38 @@ socks_5_auth_start (struct socks_connector *self) static void socks_connector_start (struct socks_connector *self); +static void +socks_connector_destroy_connector (struct socks_connector *self) +{ + if (self->connector) + { + connector_free (self->connector); + free (self->connector); + self->connector = NULL; + } +} + +static void +socks_connector_cancel_events (struct socks_connector *self) +{ + // Before calling the final callbacks, we should cancel events that + // could potentially fire; caller should destroy us immediately, though + poller_fd_reset (&self->socket_event); + poller_timer_reset (&self->timeout); +} + static void socks_connector_fail (struct socks_connector *self) { - poller_fd_reset (&self->socket_event); + socks_connector_cancel_events (self); self->on_failure (self->user_data); } static bool socks_connector_step_iterators (struct socks_connector *self) { - // At the lowest level we iterate over all addresses for the SOCKS server; - // this is done automatically by the connector + // At the lowest level we iterate over all addresses for the SOCKS server + // and just try to connect; this is done automatically by the connector // Then we iterate over available protocols if (++self->protocol_iter != SOCKS_MAX) @@ -747,13 +771,7 @@ socks_connector_step (struct socks_connector *self) self->socket_fd = -1; } - if (self->connector) - { - connector_free (self->connector); - free (self->connector); - self->connector = NULL; - } - + socks_connector_destroy_connector (self); if (socks_connector_step_iterators (self)) socks_connector_start (self); else @@ -766,6 +784,7 @@ socks_connector_on_timeout (struct socks_connector *self) if (self->on_error) self->on_error (self->user_data, "timeout"); + socks_connector_destroy_connector (self); socks_connector_fail (self); } @@ -783,11 +802,9 @@ socks_connector_on_connected (void *user_data, int socket_fd) str_reset (&self->read_buffer); str_reset (&self->write_buffer); - if ((self->protocol_iter == SOCKS_5 && socks_5_auth_start (self)) - || (self->protocol_iter == SOCKS_4A && socks_4a_start (self))) - return; - - socks_connector_fail (self); + if (!(self->protocol_iter == SOCKS_5 && socks_5_auth_start (self)) + && !(self->protocol_iter == SOCKS_4A && socks_4a_start (self))) + socks_connector_fail (self); } static void @@ -838,9 +855,13 @@ socks_connector_start (struct socks_connector *self) hard_assert (connector_add_target (connector, self->hostname, self->service, NULL)); - connector_step (connector); poller_timer_set (&self->timeout, 60 * 1000); + connector_step (connector); self->done = false; + + self->bound_port = 0; + socks_addr_free (&self->bound_address); + memset (&self->bound_address, 0, sizeof self->bound_address); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - @@ -923,8 +944,9 @@ socks_connector_on_ready } else if (self->done) { + socks_connector_cancel_events (self); + int fd = self->socket_fd; - poller_fd_reset (&self->socket_event); self->socket_fd = -1; set_blocking (fd, true); self->on_connected (self->user_data, fd); @@ -956,14 +978,8 @@ socks_connector_init (struct socks_connector *self, struct poller *poller) static void socks_connector_free (struct socks_connector *self) { - if (self->connector) - { - connector_free (self->connector); - free (self->connector); - } - - poller_fd_reset (&self->socket_event); - poller_timer_reset (&self->timeout); + socks_connector_destroy_connector (self); + socks_connector_cancel_events (self); if (self->socket_fd != -1) xclose (self->socket_fd);