/* * kike.c: the experimental IRC daemon * * Copyright (c) 2014, Přemysl Janouch * All rights reserved. * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * */ #define PROGRAM_NAME "kike" #define PROGRAM_VERSION "alpha" #include "common.c" #include // --- Configuration (application-specific) ------------------------------------ static struct config_item g_config_table[] = { { "server_name", NULL, "Server name" }, { "motd", NULL, "MOTD filename" }, { "catalog", NULL, "catgets localization catalog" }, { "bind_host", NULL, "Address of the IRC server" }, { "bind_port", "6667", "Port of the IRC server" }, { "ssl_cert", NULL, "Server SSL certificate (PEM)" }, { "ssl_key", NULL, "Server SSL private key (PEM)" }, { "max_connections", NULL, "Maximum client connections" }, { NULL, NULL, NULL } }; // --- Signals ----------------------------------------------------------------- static int g_signal_pipe[2]; ///< A pipe used to signal... signals /// Program termination has been requested by a signal static volatile sig_atomic_t g_termination_requested; static void sigterm_handler (int signum) { (void) signum; g_termination_requested = true; int original_errno = errno; if (write (g_signal_pipe[1], "t", 1) == -1) soft_assert (errno == EAGAIN); errno = original_errno; } static void setup_signal_handlers (void) { if (pipe (g_signal_pipe) == -1) exit_fatal ("%s: %s", "pipe", strerror (errno)); set_cloexec (g_signal_pipe[0]); set_cloexec (g_signal_pipe[1]); // So that the pipe cannot overflow; it would make write() block within // the signal handler, which is something we really don't want to happen. // The same holds true for read(). set_blocking (g_signal_pipe[0], false); set_blocking (g_signal_pipe[1], false); signal (SIGPIPE, SIG_IGN); struct sigaction sa; sa.sa_flags = SA_RESTART; sigemptyset (&sa.sa_mask); sa.sa_handler = sigterm_handler; if (sigaction (SIGINT, &sa, NULL) == -1 || sigaction (SIGTERM, &sa, NULL) == -1) exit_fatal ("%s: %s", "sigaction", strerror (errno)); } // --- IRC token validation ---------------------------------------------------- // Use the enum only if applicable and a simple boolean isn't sufficient. enum validation_result { VALIDATION_OK, VALIDATION_ERROR_EMPTY, VALIDATION_ERROR_TOO_LONG, VALIDATION_ERROR_INVALID }; // Everything as per RFC 2812 #define IRC_MAX_NICKNAME 9 #define IRC_MAX_HOSTNAME 63 #define IRC_MAX_MESSAGE_LENGTH 510 static bool irc_regex_match (const char *regex, const char *s) { static struct str_map cache; static bool initialized; if (!initialized) { regex_cache_init (&cache); initialized = true; } struct error *e = NULL; bool result = regex_cache_match (&cache, regex, REG_EXTENDED | REG_NOSUB, s, &e); hard_assert (!e); return result; } static const char * irc_validate_to_str (enum validation_result result) { switch (result) { case VALIDATION_OK: return "success"; case VALIDATION_ERROR_EMPTY: return "the value is empty"; case VALIDATION_ERROR_INVALID: return "invalid format"; case VALIDATION_ERROR_TOO_LONG: return "the value is too long"; default: abort (); } } // Anything to keep it as short as possible #define SN "[0-9A-Za-z][-0-9A-Za-z]*[0-9A-Za-z]*" #define N4 "[0-9]{1,3}" #define N6 "[0-9ABCDEFabcdef]{1,}" #define LE "A-Za-z" #define SP "][\\\\`_^{|}" static enum validation_result irc_validate_hostname (const char *hostname) { if (!*hostname) return VALIDATION_ERROR_EMPTY; if (!irc_regex_match ("^" SN "(\\." SN ")*$", hostname)) return VALIDATION_ERROR_INVALID; if (strlen (hostname) > IRC_MAX_HOSTNAME) return VALIDATION_ERROR_TOO_LONG; return VALIDATION_OK; } static bool irc_is_valid_hostaddr (const char *hostaddr) { if (irc_regex_match ("^" N4 "\\." N4 "\\." N4 "\\." N4 "$", hostaddr) || irc_regex_match ("^" N6 ":" N6 ":" N6 ":" N6 ":" N6 ":" N6 ":" N6 ":" N6 "$", hostaddr) || irc_regex_match ("^0:0:0:0:0:(0|[Ff]{4}):" N4 "\\." N4 "\\." N4 "\\." N4 "$", hostaddr)) return true; return false; } static bool irc_is_valid_host (const char *host) { return irc_validate_hostname (host) == VALIDATION_OK || irc_is_valid_hostaddr (host); } static bool irc_is_valid_user (const char *user) { return irc_regex_match ("^[^\r\n @]+$", user); } static bool irc_validate_nickname (const char *nickname) { if (!*nickname) return VALIDATION_ERROR_EMPTY; if (!irc_regex_match ("^[" SP LE "][" SP LE "0-9-]*$", nickname)) return VALIDATION_ERROR_INVALID; if (strlen (nickname) > IRC_MAX_NICKNAME) return VALIDATION_ERROR_TOO_LONG; return VALIDATION_OK; } #undef SN #undef N4 #undef N6 #undef LE #undef SP // --- Application data -------------------------------------------------------- #define IRC_SUPPORTED_USER_MODES "aiwros" enum { IRC_USER_MODE_INVISIBLE = (1 << 0), IRC_USER_MODE_RX_WALLOPS = (1 << 1), IRC_USER_MODE_RESTRICTED = (1 << 2), IRC_USER_MODE_OPERATOR = (1 << 3), IRC_USER_MODE_RX_SERVER_NOTICES = (1 << 4) }; struct client { struct client *next; ///< The next link in a chain struct client *prev; ///< The previous link in a chain struct server_context *ctx; ///< Server context int socket_fd; ///< The TCP socket struct str read_buffer; ///< Unprocessed input struct str write_buffer; ///< Output yet to be sent out unsigned initialized : 1; ///< Has any data been received yet? unsigned registered : 1; ///< The user has registered unsigned ssl_rx_want_tx : 1; ///< SSL_read() wants to write unsigned ssl_tx_want_rx : 1; ///< SSL_write() wants to read SSL *ssl; ///< SSL connection char *nickname; ///< IRC nickname (main identifier) char *username; ///< IRC username char *realname; ///< IRC realname (e-mail) char *hostname; ///< Hostname shown to the network unsigned mode; ///< User's mode char *away_message; ///< Away message }; static void client_init (struct client *self) { memset (self, 0, sizeof *self); self->socket_fd = -1; str_init (&self->read_buffer); str_init (&self->write_buffer); } static void client_free (struct client *self) { if (!soft_assert (self->socket_fd == -1)) xclose (self->socket_fd); if (self->ssl) SSL_free (self->ssl); str_free (&self->read_buffer); str_free (&self->write_buffer); free (self->nickname); free (self->username); free (self->realname); free (self->hostname); free (self->away_message); } static char * client_get_mode (struct client *self) { struct str mode; str_init (&mode); if (self->away_message) str_append_c (&mode, 'a'); unsigned m = self->mode; if (m & IRC_USER_MODE_INVISIBLE) str_append_c (&mode, 'i'); if (m & IRC_USER_MODE_RX_WALLOPS) str_append_c (&mode, 'w'); if (m & IRC_USER_MODE_RESTRICTED) str_append_c (&mode, 'r'); if (m & IRC_USER_MODE_OPERATOR) str_append_c (&mode, 'o'); if (m & IRC_USER_MODE_RX_SERVER_NOTICES) str_append_c (&mode, 's'); if (mode.len) return str_steal (&mode); str_free (&mode); return NULL; } #define IRC_SUPPORTED_CHAN_MODES "ov" "imnqpst" "kl" enum { IRC_CHAN_MODE_INVITE_ONLY = (1 << 0), IRC_CHAN_MODE_MODERATED = (1 << 1), IRC_CHAN_MODE_NO_OUTSIDE_MSGS = (1 << 2), IRC_CHAN_MODE_QUIET = (1 << 3), IRC_CHAN_MODE_PRIVATE = (1 << 4), IRC_CHAN_MODE_SECRET = (1 << 5), IRC_CHAN_MODE_PROTECTED_TOPIC = (1 << 6), IRC_CHAN_MODE_OPERATOR = (1 << 7), IRC_CHAN_MODE_VOICE = (1 << 8) }; struct channel_user { struct channel_user *prev; struct channel_user *next; unsigned modes; char nickname[]; }; struct channel { struct server_context *ctx; ///< Server context char *name; ///< Channel name unsigned modes; ///< Channel modes char *key; ///< Channel key long user_limit; ///< User limit or -1 struct channel_user *users; ///< Channel users struct str_vector ban_list; ///< Ban list struct str_vector exception_list; ///< Exceptions from bans struct str_vector invite_list; ///< Exceptions from +I }; static void channel_init (struct channel *self) { memset (self, 0, sizeof *self); str_vector_init (&self->ban_list); str_vector_init (&self->exception_list); str_vector_init (&self->invite_list); } static void channel_free (struct channel *self) { free (self->name); free (self->key); struct channel_user *link, *tmp; for (link = self->users; link; link = tmp) { tmp = link->next; free (link); } str_vector_free (&self->ban_list); str_vector_free (&self->exception_list); str_vector_free (&self->invite_list); } struct server_context { struct str_map config; ///< Server configuration int listen_fd; ///< Listening socket FD struct client *clients; ///< Clients SSL_CTX *ssl_ctx; ///< SSL context char *server_name; ///< Our server name struct str_map users; ///< Maps nicknames to clients struct str_map channels; ///< Maps channel names to data struct str_map handlers; ///< Message handlers struct poller poller; ///< Manages polled description bool quitting; ///< User requested quitting bool polling; ///< The event loop is running struct str_vector motd; ///< MOTD (none if empty) nl_catd catalog; ///< Message catalog for server msgs }; static void server_context_init (struct server_context *self) { str_map_init (&self->config); self->config.free = free; load_config_defaults (&self->config, g_config_table); self->listen_fd = -1; self->clients = NULL; self->server_name = NULL; str_map_init (&self->users); self->users.key_xfrm = irc_strxfrm; // TODO: set channel_free() as the free function? str_map_init (&self->channels); self->channels.key_xfrm = irc_strxfrm; str_map_init (&self->handlers); self->handlers.key_xfrm = irc_strxfrm; poller_init (&self->poller); self->quitting = false; self->polling = false; str_vector_init (&self->motd); self->catalog = (nl_catd) -1; } static void server_context_free (struct server_context *self) { str_map_free (&self->config); if (self->listen_fd != -1) xclose (self->listen_fd); if (self->ssl_ctx) SSL_CTX_free (self->ssl_ctx); // TODO: terminate the connections properly before this is called struct client *link, *tmp; for (link = self->clients; link; link = tmp) { tmp = link->next; client_free (link); free (link); } free (self->server_name); str_map_free (&self->users); str_map_free (&self->channels); str_map_free (&self->handlers); poller_free (&self->poller); str_vector_free (&self->motd); if (self->catalog != (nl_catd) -1) catclose (self->catalog); } // --- Main program ------------------------------------------------------------ static void client_kill (struct client *c, const char *reason) { // TODO: multicast a QUIT message with `reason' || "Client exited" (void) reason; // TODO: do further cleanup if the client has successfully registered etc. struct server_context *ctx = c->ctx; ssize_t i = poller_find_by_fd (&ctx->poller, c->socket_fd); if (i != -1) poller_remove_at_index (&ctx->poller, i); xclose (c->socket_fd); c->socket_fd = -1; client_free (c); LIST_UNLINK (ctx->clients, c); free (c); } static void irc_send_str (struct client *c, const struct str *s) { // TODO: kill the connection above some "SendQ" threshold (careful!) str_append_data (&c->write_buffer, s->str, s->len > IRC_MAX_MESSAGE_LENGTH ? IRC_MAX_MESSAGE_LENGTH : s->len); str_append (&c->write_buffer, "\r\n"); } static void irc_send (struct client *c, const char *format, ...) ATTRIBUTE_PRINTF (2, 3); static void irc_send (struct client *c, const char *format, ...) { struct str tmp; str_init (&tmp); va_list ap; va_start (ap, format); str_append_vprintf (&tmp, format, ap); va_end (ap); irc_send_str (c, &tmp); str_free (&tmp); } static const char * irc_get_text (struct server_context *ctx, int id, const char *def) { if (!soft_assert (def != NULL)) def = ""; if (ctx->catalog == (nl_catd) -1) return def; return catgets (ctx->catalog, 1, id, def); } // --- IRC command handling ---------------------------------------------------- enum { IRC_RPL_WELCOME = 1, IRC_RPL_YOURHOST = 2, IRC_RPL_CREATED = 3, IRC_RPL_MYINFO = 4, IRC_RPL_MOTD = 372, IRC_RPL_MOTDSTART = 375, IRC_RPL_ENDOFMOTD = 376, IRC_ERR_NOORIGIN = 409, IRC_ERR_UNKNOWNCOMMAND = 421, IRC_ERR_NOMOTD = 422, IRC_ERR_NONICKNAMEGIVEN = 431, IRC_ERR_ERRONEOUSNICKNAME = 432, IRC_ERR_NICKNAMEINUSE = 433, IRC_ERR_NOTREGISTERED = 451, IRC_ERR_NEEDMOREPARAMS = 461, IRC_ERR_ALREADYREGISTERED = 462 }; static const char *g_default_replies[] = { [IRC_RPL_WELCOME] = ":Welcome to the Internet Relay Network %s!%s@%s", [IRC_RPL_YOURHOST] = ":Your host is %s, running version %s", [IRC_RPL_CREATED] = ":This server was created %s", [IRC_RPL_MYINFO] = "%s %s %s %s", [IRC_RPL_MOTD] = ":- %s", [IRC_RPL_MOTDSTART] = ":- %s Message of the day - ", [IRC_RPL_ENDOFMOTD] = ":End of MOTD command", [IRC_ERR_NOORIGIN] = ":No origin specified", [IRC_ERR_UNKNOWNCOMMAND] = "%s: Unknown command", [IRC_ERR_NOMOTD] = ":MOTD File is missing", [IRC_ERR_NONICKNAMEGIVEN] = ":No nickname given", [IRC_ERR_ERRONEOUSNICKNAME] = "%s :Erroneous nickname", [IRC_ERR_NICKNAMEINUSE] = "%s :Nickname is already in use", [IRC_ERR_NOTREGISTERED] = "%s :You have not registered", [IRC_ERR_NEEDMOREPARAMS] = "%s :Not enough parameters", [IRC_ERR_ALREADYREGISTERED] = ":Unauthorized command (already registered)", }; // XXX: this way we cannot typecheck the arguments, so we must be careful static void irc_send_reply (struct client *c, int id, ...) { struct str tmp; str_init (&tmp); va_list ap; va_start (ap, id); str_append_printf (&tmp, ":%s %03d %s ", c->ctx->server_name, id, c->nickname ? c->nickname : ""); str_append_vprintf (&tmp, irc_get_text (c->ctx, id, g_default_replies[id]), ap); va_end (ap); irc_send_str (c, &tmp); str_free (&tmp); } static void irc_send_motd (struct client *c) { struct server_context *ctx = c->ctx; if (!ctx->motd.len) { irc_send_reply (c, IRC_ERR_NOMOTD); return; } irc_send_reply (c, IRC_RPL_MOTDSTART, ctx->server_name); for (size_t i = 0; i < ctx->motd.len; i++) irc_send_reply (c, IRC_RPL_MOTD, ctx->motd.vector[i]); irc_send_reply (c, IRC_RPL_ENDOFMOTD); } static void irc_try_finish_registration (struct client *c) { struct server_context *ctx = c->ctx; if (!c->nickname || !c->username || !c->realname) return; c->registered = true; irc_send_reply (c, IRC_RPL_WELCOME, c->nickname, c->username, c->hostname); irc_send_reply (c, IRC_RPL_YOURHOST, ctx->server_name, PROGRAM_VERSION); // The purpose of this message eludes me irc_send_reply (c, IRC_RPL_CREATED, __DATE__); irc_send_reply (c, IRC_RPL_MYINFO, ctx->server_name, PROGRAM_VERSION, IRC_SUPPORTED_USER_MODES, IRC_SUPPORTED_CHAN_MODES); // Although not strictly required, bots often need this to work irc_send_motd (c); char *mode = client_get_mode (c); if (mode) irc_send (c, ":%s MODE %s :+%s", c->nickname, c->nickname, mode); free (mode); } static void irc_handle_pass (const struct irc_message *msg, struct client *c) { if (c->registered) irc_send_reply (c, IRC_ERR_ALREADYREGISTERED); else if (msg->params.len < 1) irc_send_reply (c, IRC_ERR_NEEDMOREPARAMS, msg->command); // We have SSL client certificates for this purpose; ignoring } static void irc_handle_nick (const struct irc_message *msg, struct client *c) { struct server_context *ctx = c->ctx; if (c->registered) { irc_send_reply (c, IRC_ERR_ALREADYREGISTERED); return; } if (msg->params.len < 1) { irc_send_reply (c, IRC_ERR_NONICKNAMEGIVEN); return; } const char *nickname = msg->params.vector[0]; if (irc_validate_nickname (nickname) != VALIDATION_OK) { irc_send_reply (c, IRC_ERR_ERRONEOUSNICKNAME, nickname); return; } if (c->nickname) { str_map_set (&ctx->users, c->nickname, NULL); free (c->nickname); } if (str_map_find (&ctx->users, nickname)) { irc_send_reply (c, IRC_ERR_NICKNAMEINUSE, nickname); return; } // Allocate the nickname c->nickname = xstrdup (nickname); str_map_set (&ctx->users, nickname, c); irc_try_finish_registration (c); } static void irc_handle_user (const struct irc_message *msg, struct client *c) { if (c->registered) { irc_send_reply (c, IRC_ERR_ALREADYREGISTERED); return; } if (msg->params.len < 4) { irc_send_reply (c, IRC_ERR_NEEDMOREPARAMS, msg->command); return; } const char *username = msg->params.vector[0]; const char *mode = msg->params.vector[1]; const char *realname = msg->params.vector[3]; // Unfortunately the protocol doesn't give us any means of rejecting it if (!irc_is_valid_user (username)) username = "xxx"; free (c->username); c->username = xstrdup (username); free (c->realname); c->realname = xstrdup (realname); unsigned long m; if (xstrtoul (&m, mode, 10)) { if (m & 4) c->mode |= IRC_USER_MODE_RX_WALLOPS; if (m & 8) c->mode |= IRC_USER_MODE_INVISIBLE; } irc_try_finish_registration (c); } static void irc_handle_ping (const struct irc_message *msg, struct client *c) { // XXX: the RFC is pretty incomprehensible about the exact usage if (msg->params.len < 1) irc_send_reply (c, IRC_ERR_NOORIGIN); else irc_send (c, ":%s PONG :%s", c->ctx->server_name, msg->params.vector[0]); } // ----------------------------------------------------------------------------- struct irc_command { const char *name; bool requires_registration; void (*handler) (const struct irc_message *, struct client *); }; static void irc_register_handlers (struct server_context *ctx) { static const struct irc_command message_handlers[] = { { "PASS", false, irc_handle_pass }, { "NICK", false, irc_handle_nick }, { "USER", false, irc_handle_user }, { "PING", true, irc_handle_ping } }; for (size_t i = 0; i < N_ELEMENTS (message_handlers); i++) { const struct irc_command *cmd = &message_handlers[i]; str_map_set (&ctx->handlers, cmd->name, (void *) cmd); } } static void irc_process_message (const struct irc_message *msg, const char *raw, void *user_data) { (void) raw; // XXX: we may want to discard everything following a QUIT etc. // We can set a flag within the client object. // TODO: see RFC 2812 :! struct client *c = user_data; struct irc_command *cmd = str_map_find (&c->ctx->handlers, msg->command); if (!cmd) irc_send_reply (c, IRC_ERR_UNKNOWNCOMMAND, msg->command); else if (cmd->requires_registration && !c->registered) irc_send_reply (c, IRC_ERR_NOTREGISTERED); else cmd->handler (msg, c); } // --- Network I/O ------------------------------------------------------------- static bool irc_try_read (struct client *c) { struct str *buf = &c->read_buffer; ssize_t n_read; while (true) { str_ensure_space (buf, 512); n_read = recv (c->socket_fd, buf->str + buf->len, buf->alloc - buf->len - 1 /* null byte */, 0); if (n_read > 0) { buf->str[buf->len += n_read] = '\0'; // TODO: discard characters above the 512 character limit irc_process_buffer (buf, irc_process_message, c); continue; } if (n_read == 0) { client_kill (c, NULL); return false; } if (errno == EAGAIN) return true; if (errno == EINTR) continue; print_debug ("%s: %s: %s", __func__, "recv", strerror (errno)); client_kill (c, strerror (errno)); return false; } } static bool irc_try_read_ssl (struct client *c) { if (c->ssl_tx_want_rx) return true; struct str *buf = &c->read_buffer; c->ssl_rx_want_tx = false; while (true) { str_ensure_space (buf, 512); int n_read = SSL_read (c->ssl, buf->str + buf->len, buf->alloc - buf->len - 1 /* null byte */); const char *error_info = NULL; switch (xssl_get_error (c->ssl, n_read, &error_info)) { case SSL_ERROR_NONE: buf->str[buf->len += n_read] = '\0'; // TODO: discard characters above the 512 character limit irc_process_buffer (buf, irc_process_message, c); continue; case SSL_ERROR_ZERO_RETURN: client_kill (c, NULL); return false; case SSL_ERROR_WANT_READ: return true; case SSL_ERROR_WANT_WRITE: c->ssl_rx_want_tx = true; return true; case XSSL_ERROR_TRY_AGAIN: continue; default: print_debug ("%s: %s: %s", __func__, "SSL_read", error_info); client_kill (c, error_info); return false; } } } static bool irc_try_write (struct client *c) { struct str *buf = &c->write_buffer; ssize_t n_written; while (buf->len) { n_written = send (c->socket_fd, buf->str, buf->len, 0); if (n_written >= 0) { str_remove_slice (buf, 0, n_written); continue; } if (errno == EAGAIN) return true; if (errno == EINTR) continue; print_debug ("%s: %s: %s", __func__, "send", strerror (errno)); client_kill (c, strerror (errno)); return false; } return true; } static bool irc_try_write_ssl (struct client *c) { if (c->ssl_rx_want_tx) return true; struct str *buf = &c->write_buffer; c->ssl_tx_want_rx = false; while (buf->len) { int n_written = SSL_write (c->ssl, buf->str, buf->len); const char *error_info = NULL; switch (xssl_get_error (c->ssl, n_written, &error_info)) { case SSL_ERROR_NONE: str_remove_slice (buf, 0, n_written); continue; case SSL_ERROR_ZERO_RETURN: client_kill (c, NULL); return false; case SSL_ERROR_WANT_WRITE: return true; case SSL_ERROR_WANT_READ: c->ssl_tx_want_rx = true; return true; case XSSL_ERROR_TRY_AGAIN: continue; default: print_debug ("%s: %s: %s", __func__, "SSL_write", error_info); client_kill (c, error_info); return false; } } return true; } static bool irc_autodetect_ssl (struct client *c) { // Trivial SSL/TLS autodetection. The first block of data returned by // recv() must be at least three bytes long for this to work reliably, // but that should not pose a problem in practice. // // SSL2: 1xxx xxxx | xxxx xxxx | <1> // (message length) (client hello) // SSL3/TLS: <22> | <3> | xxxx xxxx // (handshake)| (protocol version) // // Such byte sequences should never occur at the beginning of regular IRC // communication, which usually begins with USER/NICK/PASS/SERVICE. char buf[3]; start: switch (recv (c->socket_fd, buf, sizeof buf, MSG_PEEK)) { case 3: if ((buf[0] & 0x80) && buf[2] == 1) return true; case 2: if (buf[0] == 22 && buf[1] == 3) return true; break; case 1: if (buf[0] == 22) return true; break; case 0: break; default: if (errno == EINTR) goto start; } return false; } static bool client_initialize_ssl (struct client *c) { // SSL support not enabled if (!c->ctx->ssl_ctx) return false; c->ssl = SSL_new (c->ctx->ssl_ctx); if (!c->ssl) goto error_ssl_1; if (!SSL_set_fd (c->ssl, c->socket_fd)) goto error_ssl_2; SSL_set_accept_state (c->ssl); return true; error_ssl_2: SSL_free (c->ssl); c->ssl = NULL; error_ssl_1: // XXX: these error strings are really nasty; also there could be // multiple errors on the OpenSSL stack. print_debug ("%s: %s: %s", "could not initialize SSL", c->hostname, ERR_error_string (ERR_get_error (), NULL)); return false; } static void on_irc_client_ready (const struct pollfd *pfd, void *user_data) { struct client *c = user_data; if (!c->initialized) { hard_assert (pfd->events == POLLIN); if (irc_autodetect_ssl (c) && !client_initialize_ssl (c)) { client_kill (c, NULL); return; } c->initialized = true; } int new_events = 0; if (c->ssl) { // Reads may want to write, writes may want to read, poll() may // return unexpected things in `revents'... let's try both if (!irc_try_read_ssl (c) || !irc_try_write_ssl (c)) return; new_events |= POLLIN; if (c->write_buffer.len || c->ssl_rx_want_tx) new_events |= POLLOUT; // While we're waiting for an opposite event, we ignore the original if (c->ssl_rx_want_tx) new_events &= ~POLLIN; if (c->ssl_tx_want_rx) new_events &= ~POLLOUT; } else { if (!irc_try_read (c) || !irc_try_write (c)) return; new_events |= POLLIN; if (c->write_buffer.len) new_events |= POLLOUT; } hard_assert (new_events != 0); if (pfd->events != new_events) poller_set (&c->ctx->poller, c->socket_fd, new_events, (poller_dispatcher_func) on_irc_client_ready, c); } static void on_irc_client_available (const struct pollfd *pfd, void *user_data) { (void) pfd; struct server_context *ctx = user_data; // TODO: stop accepting new connections when `max_connections' is reached while (true) { // XXX: `struct sockaddr_storage' is not the most portable thing struct sockaddr_storage peer; socklen_t peer_len = sizeof peer; int fd = accept (ctx->listen_fd, (struct sockaddr *) &peer, &peer_len); if (fd == -1) { if (errno == EAGAIN) break; if (errno == EINTR) continue; if (errno == ECONNABORTED) continue; // TODO: handle resource exhaustion (EMFILE, ENFILE) specially // (stop accepting new connections and wait until we close some). // FIXME: handle this better, bring the server down cleanly. exit_fatal ("%s: %s", "accept", strerror (errno)); } char host[NI_MAXHOST] = "unknown", port[NI_MAXSERV] = "unknown"; int err = getnameinfo ((struct sockaddr *) &peer, peer_len, host, sizeof host, port, sizeof port, NI_NUMERICSERV); if (err) print_debug ("%s: %s", "getnameinfo", gai_strerror (err)); print_debug ("accepted connection from %s:%s", host, port); struct client *c = xmalloc (sizeof *c); client_init (c); c->ctx = ctx; c->socket_fd = fd; c->hostname = xstrdup (host); LIST_PREPEND (ctx->clients, c); // TODO: set a timeout on the socket, something like 3 minutes, then we // should terminate the connection. set_blocking (fd, false); poller_set (&ctx->poller, fd, POLLIN, (poller_dispatcher_func) on_irc_client_ready, c); } } // ----------------------------------------------------------------------------- static int irc_ssl_verify_callback (int verify_ok, X509_STORE_CTX *ctx) { (void) verify_ok; (void) ctx; // We only want to provide additional privileges based on the client's // certificate, so let's not terminate the connection because of a failure. return 1; } static bool irc_initialize_ssl (struct server_context *ctx, struct error **e) { const char *ssl_cert = str_map_find (&ctx->config, "ssl_cert"); const char *ssl_key = str_map_find (&ctx->config, "ssl_key"); // Only try to enable SSL support if the user configures it; it is not // a failure if no one has requested it. if (!ssl_cert && !ssl_key) return true; if (!ssl_cert) error_set (e, "no SSL certificate set"); else if (!ssl_key) error_set (e, "no SSL private key set"); if (!ssl_cert || !ssl_key) return false; char *cert_path = resolve_config_filename (ssl_cert); char *key_path = resolve_config_filename (ssl_key); if (!cert_path) error_set (e, "%s: %s", "cannot open file", ssl_cert); else if (!key_path) error_set (e, "%s: %s", "cannot open file", ssl_key); if (!cert_path || !key_path) return false; ctx->ssl_ctx = SSL_CTX_new (SSLv23_server_method ()); if (!ctx->ssl_ctx) { // XXX: these error strings are really nasty; also there could be // multiple errors on the OpenSSL stack. error_set (e, "%s: %s", "could not initialize SSL", ERR_error_string (ERR_get_error (), NULL)); goto error_ssl_1; } SSL_CTX_set_verify (ctx->ssl_ctx, SSL_VERIFY_PEER | SSL_VERIFY_CLIENT_ONCE, irc_ssl_verify_callback); // XXX: maybe we should call SSL_CTX_set_options() for some workarounds // XXX: perhaps we should read the files ourselves for better messages if (!SSL_CTX_use_certificate_chain_file (ctx->ssl_ctx, cert_path)) { error_set (e, "%s: %s", "setting the SSL client certificate failed", ERR_error_string (ERR_get_error (), NULL)); goto error_ssl_2; } if (!SSL_CTX_use_PrivateKey_file (ctx->ssl_ctx, key_path, SSL_FILETYPE_PEM)) { error_set (e, "%s: %s", "setting the SSL private key failed", ERR_error_string (ERR_get_error (), NULL)); goto error_ssl_2; } // TODO: SSL_CTX_check_private_key()? It has probably already been checked // by SSL_CTX_use_PrivateKey_file() above. // Gah, spare me your awkward semantics, I just want to push data! // XXX: do we want SSL_MODE_AUTO_RETRY as well? I guess not. SSL_CTX_set_mode (ctx->ssl_ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER | SSL_MODE_ENABLE_PARTIAL_WRITE); return true; error_ssl_2: SSL_CTX_free (ctx->ssl_ctx); ctx->ssl_ctx = NULL; error_ssl_1: return false; } static bool irc_initialize_catalog (struct server_context *ctx, struct error **e) { hard_assert (ctx->catalog == (nl_catd) -1); const char *catalog = str_map_find (&ctx->config, "catalog"); if (!catalog) return true; char *path = resolve_config_filename (catalog); if (!path) { error_set (e, "%s: %s", "cannot open file", catalog); return false; } ctx->catalog = catopen (path, NL_CAT_LOCALE); free (path); if (ctx->catalog == (nl_catd) -1) { error_set (e, "%s: %s", "failed reading the message catalog file", strerror (errno)); return false; } return true; } static bool irc_initialize_motd (struct server_context *ctx, struct error **e) { hard_assert (ctx->motd.len == 0); const char *motd = str_map_find (&ctx->config, "motd"); if (!motd) return true; char *path = resolve_config_filename (motd); if (!path) { error_set (e, "%s: %s", "cannot open file", motd); return false; } FILE *fp = fopen (path, "r"); free (path); if (!fp) { error_set (e, "%s: %s", "failed reading the MOTD file", strerror (errno)); return false; } struct str line; str_init (&line); while (read_line (fp, &line)) str_vector_add_owned (&ctx->motd, str_steal (&line)); str_free (&line); fclose (fp); return true; } static bool irc_initialize_server_name (struct server_context *ctx, struct error **e) { enum validation_result res; const char *server_name = str_map_find (&ctx->config, "server_name"); if (server_name) { res = irc_validate_hostname (server_name); if (res != VALIDATION_OK) { error_set (e, "invalid configuration value for `%s': %s", "server_name", irc_validate_to_str (res)); return false; } ctx->server_name = xstrdup (server_name); } else { char hostname[HOST_NAME_MAX]; if (gethostname (hostname, sizeof hostname)) { error_set (e, "%s: %s", "getting the hostname failed", strerror (errno)); return false; } res = irc_validate_hostname (hostname); if (res != VALIDATION_OK) { error_set (e, "`%s' is not set and the hostname (`%s') cannot be used: %s", "server_name", hostname, irc_validate_to_str (res)); return false; } ctx->server_name = xstrdup (hostname); } return true; } static bool irc_listen (struct server_context *ctx, struct error **e) { const char *bind_host = str_map_find (&ctx->config, "bind_host"); const char *bind_port = str_map_find (&ctx->config, "bind_port"); hard_assert (bind_port != NULL); // We have a default value for this struct addrinfo gai_hints, *gai_result, *gai_iter; memset (&gai_hints, 0, sizeof gai_hints); gai_hints.ai_socktype = SOCK_STREAM; gai_hints.ai_flags = AI_PASSIVE; int err = getaddrinfo (bind_host, bind_port, &gai_hints, &gai_result); if (err) { error_set (e, "%s: %s: %s", "network setup failed", "getaddrinfo", gai_strerror (err)); return false; } int sockfd; char real_host[NI_MAXHOST], real_port[NI_MAXSERV]; for (gai_iter = gai_result; gai_iter; gai_iter = gai_iter->ai_next) { sockfd = socket (gai_iter->ai_family, gai_iter->ai_socktype, gai_iter->ai_protocol); if (sockfd == -1) continue; set_cloexec (sockfd); int yes = 1; soft_assert (setsockopt (sockfd, SOL_SOCKET, SO_KEEPALIVE, &yes, sizeof yes) != -1); soft_assert (setsockopt (sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof yes) != -1); real_host[0] = real_port[0] = '\0'; err = getnameinfo (gai_iter->ai_addr, gai_iter->ai_addrlen, real_host, sizeof real_host, real_port, sizeof real_port, NI_NUMERICHOST | NI_NUMERICSERV); if (err) print_debug ("%s: %s", "getnameinfo", gai_strerror (err)); if (bind (sockfd, gai_iter->ai_addr, gai_iter->ai_addrlen)) print_error ("bind to %s:%s failed: %s", real_host, real_port, strerror (errno)); else if (listen (sockfd, 16 /* arbitrary number */)) print_error ("listen at %s:%s failed: %s", real_host, real_port, strerror (errno)); else break; xclose (sockfd); } freeaddrinfo (gai_result); if (!gai_iter) { error_set (e, "network setup failed"); return false; } set_blocking (sockfd, false); ctx->listen_fd = sockfd; poller_set (&ctx->poller, ctx->listen_fd, POLLIN, (poller_dispatcher_func) on_irc_client_available, ctx); print_status ("listening at %s:%s", real_host, real_port); return true; } static void on_signal_pipe_readable (const struct pollfd *fd, struct server_context *ctx) { char *dummy; (void) read (fd->fd, &dummy, 1); // TODO: send ERROR messages to anyone, wait for the messages to get // dispatched for a few seconds, RST the rest and quit. if (g_termination_requested && !ctx->quitting) { #if 0 initiate_quit (ctx); #endif } } static void daemonize (void) { // TODO: create and lock a PID file? print_status ("daemonizing..."); if (chdir ("/")) exit_fatal ("%s: %s", "chdir", strerror (errno)); pid_t pid; if ((pid = fork ()) < 0) exit_fatal ("%s: %s", "fork", strerror (errno)); else if (pid) exit (EXIT_SUCCESS); setsid (); signal (SIGHUP, SIG_IGN); if ((pid = fork ()) < 0) exit_fatal ("%s: %s", "fork", strerror (errno)); else if (pid) exit (EXIT_SUCCESS); openlog (PROGRAM_NAME, LOG_NDELAY | LOG_NOWAIT | LOG_PID, 0); g_log_message_real = log_message_syslog; // XXX: we may close our own descriptors this way, crippling ourselves for (int i = 0; i < 3; i++) xclose (i); int tty = open ("/dev/null", O_RDWR); if (tty != 0 || dup (0) != 1 || dup (0) != 2) exit_fatal ("failed to reopen FD's: %s", strerror (errno)); } static void print_usage (const char *program_name) { fprintf (stderr, "Usage: %s [OPTION]...\n" "Experimental IRC server.\n" "\n" " -d, --debug run in debug mode (do not daemonize)\n" " -h, --help display this help and exit\n" " -V, --version output version information and exit\n" " --write-default-cfg [filename]\n" " write a default configuration file and exit\n", program_name); } int main (int argc, char *argv[]) { const char *invocation_name = argv[0]; static struct option opts[] = { { "debug", no_argument, NULL, 'd' }, { "help", no_argument, NULL, 'h' }, { "version", no_argument, NULL, 'V' }, { "write-default-cfg", optional_argument, NULL, 'w' }, { NULL, 0, NULL, 0 } }; while (1) { int c, opt_index; c = getopt_long (argc, argv, "dhV", opts, &opt_index); if (c == -1) break; switch (c) { case 'd': g_debug_mode = true; break; case 'h': print_usage (invocation_name); exit (EXIT_SUCCESS); case 'V': printf (PROGRAM_NAME " " PROGRAM_VERSION "\n"); exit (EXIT_SUCCESS); case 'w': call_write_default_config (optarg, g_config_table); exit (EXIT_SUCCESS); default: print_error ("wrong options"); exit (EXIT_FAILURE); } } print_status (PROGRAM_NAME " " PROGRAM_VERSION " starting"); setup_signal_handlers (); SSL_library_init (); atexit (EVP_cleanup); SSL_load_error_strings (); // XXX: ERR_load_BIO_strings()? Anything else? atexit (ERR_free_strings); struct server_context ctx; server_context_init (&ctx); irc_register_handlers (&ctx); struct error *e = NULL; if (!read_config_file (&ctx.config, &e)) { print_error ("error loading configuration: %s", e->message); error_free (e); exit (EXIT_FAILURE); } poller_set (&ctx.poller, g_signal_pipe[0], POLLIN, (poller_dispatcher_func) on_signal_pipe_readable, &ctx); if (!irc_initialize_ssl (&ctx, &e) || !irc_initialize_server_name (&ctx, &e) || !irc_initialize_motd (&ctx, &e) || !irc_initialize_catalog (&ctx, &e) || !irc_listen (&ctx, &e)) { print_error ("%s", e->message); error_free (e); exit (EXIT_FAILURE); } if (!g_debug_mode) daemonize (); ctx.polling = true; while (ctx.polling) poller_run (&ctx.poller); server_context_free (&ctx); return EXIT_SUCCESS; }