/* * common.c: common functionality * * Copyright (c) 2014 - 2015, Přemysl Janouch * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted. * * 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 LIBERTY_WANT_SSL #define LIBERTY_WANT_ASYNC #define LIBERTY_WANT_POLLER #define LIBERTY_WANT_PROTO_IRC #ifdef WANT_SYSLOG_LOGGING #define print_fatal_data ((void *) LOG_ERR) #define print_error_data ((void *) LOG_ERR) #define print_warning_data ((void *) LOG_WARNING) #define print_status_data ((void *) LOG_INFO) #define print_debug_data ((void *) LOG_DEBUG) #endif // WANT_SYSLOG_LOGGING #include "liberty/liberty.c" #include #include static void init_openssl (void) { #if OPENSSL_VERSION_NUMBER < 0x10100000L || LIBRESSL_VERSION_NUMBER SSL_library_init (); // XXX: this list is probably not complete atexit (EVP_cleanup); SSL_load_error_strings (); atexit (ERR_free_strings); #else // Cleanup is done automatically via atexit() OPENSSL_init_ssl (0, NULL); #endif } // --- To be moved to liberty -------------------------------------------------- static void cstr_set (char **s, char *new) { free (*s); *s = new; } static ssize_t strv_find (const struct strv *v, const char *s) { for (size_t i = 0; i < v->len; i++) if (!strcmp (v->vector[i], s)) return i; return -1; } static time_t unixtime_msec (long *msec) { #ifdef _POSIX_TIMERS struct timespec tp; hard_assert (clock_gettime (CLOCK_REALTIME, &tp) != -1); *msec = tp.tv_nsec / 1000000; #else // ! _POSIX_TIMERS struct timeval tp; hard_assert (gettimeofday (&tp, NULL) != -1); *msec = tp.tv_usec / 1000; #endif // ! _POSIX_TIMERS return tp.tv_sec; } /// This differs from the non-unique version in that we expect the filename /// to be something like a pattern for mkstemp(), so the resulting path can /// reside in a system-wide directory with no risk of a conflict. static char * resolve_relative_runtime_unique_filename (const char *filename) { const char *runtime_dir = getenv ("XDG_RUNTIME_DIR"); const char *tmpdir = getenv ("TMPDIR"); struct str path = str_make (); if (runtime_dir && *runtime_dir == '/') str_append (&path, runtime_dir); else if (tmpdir && *tmpdir == '/') str_append (&path, tmpdir); else str_append (&path, "/tmp"); str_append_printf (&path, "/%s/%s", PROGRAM_NAME, filename); // Try to create the file's ancestors; // typically the user will want to immediately create a file in there const char *last_slash = strrchr (path.str, '/'); if (last_slash && last_slash != path.str) { char *copy = xstrndup (path.str, last_slash - path.str); (void) mkdir_with_parents (copy, NULL); free (copy); } return str_steal (&path); } static bool xwrite (int fd, const char *data, size_t len, struct error **e) { size_t written = 0; while (written < len) { ssize_t res = write (fd, data + written, len - written); if (res >= 0) written += res; else if (errno != EINTR) return error_set (e, "%s", strerror (errno)); } return true; } // --- Logging ----------------------------------------------------------------- static void log_message_syslog (void *user_data, const char *quote, const char *fmt, va_list ap) { int prio = (int) (intptr_t) user_data; va_list va; va_copy (va, ap); int size = vsnprintf (NULL, 0, fmt, va); va_end (va); if (size < 0) return; char buf[size + 1]; if (vsnprintf (buf, sizeof buf, fmt, ap) >= 0) syslog (prio, "%s%s", quote, buf); } // --- SOCKS 5/4a -------------------------------------------------------------- // Asynchronous SOCKS connector. Adds more stuff on top of the regular one. // Note that the `username' is used differently in SOCKS 4a and 5. In the // former version, it is the username that you can get ident'ed against. // In the latter version, it forms a pair with the password field and doesn't // need to be an actual user on your machine. struct socks_addr { enum socks_addr_type { SOCKS_IPV4 = 1, ///< IPv4 address SOCKS_DOMAIN = 3, ///< Domain name to be resolved SOCKS_IPV6 = 4 ///< IPv6 address } type; ///< The type of this address union { uint8_t ipv4[4]; ///< IPv4 address, network octet order char *domain; ///< Domain name uint8_t ipv6[16]; ///< IPv6 address, network octet order } data; ///< The address itself }; static void socks_addr_free (struct socks_addr *self) { if (self->type == SOCKS_DOMAIN) free (self->data.domain); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - struct socks_target { LIST_HEADER (struct socks_target) char *address_str; ///< Target address as a string struct socks_addr address; ///< Target address uint16_t port; ///< Target service port }; enum socks_protocol { SOCKS_5, ///< SOCKS5 SOCKS_4A, ///< SOCKS4A SOCKS_MAX ///< End of protocol }; static inline const char * socks_protocol_to_string (enum socks_protocol self) { switch (self) { case SOCKS_5: return "SOCKS5"; case SOCKS_4A: return "SOCKS4A"; default: return NULL; } } struct socks_connector { struct connector *connector; ///< Proxy server iterator (effectively) enum socks_protocol protocol_iter; ///< Protocol iterator struct socks_target *targets_iter; ///< Targets iterator // 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 bool done; ///< Tunnel succesfully established uint8_t bound_address_len; ///< Length of domain name 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 *); // Configuration: char *hostname; ///< SOCKS server hostname char *service; ///< SOCKS server service name or port char *username; ///< Username for authentication char *password; ///< Password for authentication struct socks_target *targets; ///< Targets struct socks_target *targets_tail; ///< Tail of targets 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 void (*on_connected) (void *user_data, int socket, const char *hostname); /// 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, const char *via, const char *version); /// Connecting to the last address has failed 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__); \ if (self->on_error) \ self->on_error (self->user_data, error); \ free (error); \ return false; \ BLOCK_END #define SOCKS_DATA_CB(name) static bool name \ (struct socks_connector *self, struct msg_unpacker *unpacker) #define SOCKS_GO(name, data_needed_) \ self->on_data = name; \ self->data_needed = data_needed_; \ return true // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SOCKS_DATA_CB (socks_4a_finish) { uint8_t null, status; hard_assert (msg_unpacker_u8 (unpacker, &null)); hard_assert (msg_unpacker_u8 (unpacker, &status)); if (null != 0) SOCKS_FAIL ("protocol error"); switch (status) { case 90: self->done = true; return false; case 91: SOCKS_FAIL ("request rejected or failed"); case 92: SOCKS_FAIL ("%s: %s", "request rejected", "SOCKS server cannot connect to identd on the client"); case 93: SOCKS_FAIL ("%s: %s", "request rejected", "identd reports different user-id"); default: SOCKS_FAIL ("protocol error"); } } static bool socks_4a_start (struct socks_connector *self) { struct socks_target *target = self->targets_iter; const void *dest_ipv4 = "\x00\x00\x00\x01"; const char *dest_domain = NULL; char buf[INET6_ADDRSTRLEN]; switch (target->address.type) { case SOCKS_IPV4: dest_ipv4 = target->address.data.ipv4; break; case SOCKS_IPV6: // About the best thing we can do, not sure if it works anywhere at all if (!inet_ntop (AF_INET6, &target->address.data.ipv6, buf, sizeof buf)) SOCKS_FAIL ("%s: %s", "inet_ntop", strerror (errno)); dest_domain = buf; break; case SOCKS_DOMAIN: dest_domain = target->address.data.domain; } struct str *wb = &self->write_buffer; str_pack_u8 (wb, 4); // version str_pack_u8 (wb, 1); // connect str_pack_u16 (wb, target->port); // port str_append_data (wb, dest_ipv4, 4); // destination address if (self->username) str_append (wb, self->username); str_append_c (wb, '\0'); if (dest_domain) { str_append (wb, dest_domain); str_append_c (wb, '\0'); } SOCKS_GO (socks_4a_finish, 8); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SOCKS_DATA_CB (socks_5_request_port) { hard_assert (msg_unpacker_u16 (unpacker, &self->bound_port)); self->done = true; return false; } SOCKS_DATA_CB (socks_5_request_ipv4) { memcpy (self->bound_address.data.ipv4, unpacker->data, unpacker->len); SOCKS_GO (socks_5_request_port, 2); } SOCKS_DATA_CB (socks_5_request_ipv6) { memcpy (self->bound_address.data.ipv6, unpacker->data, unpacker->len); SOCKS_GO (socks_5_request_port, 2); } SOCKS_DATA_CB (socks_5_request_domain_data) { self->bound_address.data.domain = xstrndup (unpacker->data, unpacker->len); SOCKS_GO (socks_5_request_port, 2); } SOCKS_DATA_CB (socks_5_request_domain) { hard_assert (msg_unpacker_u8 (unpacker, &self->bound_address_len)); SOCKS_GO (socks_5_request_domain_data, self->bound_address_len); } SOCKS_DATA_CB (socks_5_request_finish) { uint8_t version, status, reserved, type; hard_assert (msg_unpacker_u8 (unpacker, &version)); hard_assert (msg_unpacker_u8 (unpacker, &status)); hard_assert (msg_unpacker_u8 (unpacker, &reserved)); hard_assert (msg_unpacker_u8 (unpacker, &type)); if (version != 0x05) SOCKS_FAIL ("protocol error"); switch (status) { case 0x00: break; case 0x01: SOCKS_FAIL ("general SOCKS server failure"); case 0x02: SOCKS_FAIL ("connection not allowed by ruleset"); case 0x03: SOCKS_FAIL ("network unreachable"); case 0x04: SOCKS_FAIL ("host unreachable"); case 0x05: SOCKS_FAIL ("connection refused"); case 0x06: SOCKS_FAIL ("TTL expired"); case 0x07: SOCKS_FAIL ("command not supported"); case 0x08: SOCKS_FAIL ("address type not supported"); default: SOCKS_FAIL ("protocol error"); } switch ((self->bound_address.type = type)) { case SOCKS_IPV4: SOCKS_GO (socks_5_request_ipv4, sizeof self->bound_address.data.ipv4); case SOCKS_IPV6: SOCKS_GO (socks_5_request_ipv6, sizeof self->bound_address.data.ipv6); case SOCKS_DOMAIN: SOCKS_GO (socks_5_request_domain, 1); default: SOCKS_FAIL ("protocol error"); } } static bool socks_5_request_start (struct socks_connector *self) { struct socks_target *target = self->targets_iter; struct str *wb = &self->write_buffer; str_pack_u8 (wb, 0x05); // version str_pack_u8 (wb, 0x01); // connect str_pack_u8 (wb, 0x00); // reserved str_pack_u8 (wb, target->address.type); switch (target->address.type) { case SOCKS_IPV4: str_append_data (wb, target->address.data.ipv4, sizeof target->address.data.ipv4); break; case SOCKS_DOMAIN: { size_t dlen = strlen (target->address.data.domain); if (dlen > 255) dlen = 255; str_pack_u8 (wb, dlen); str_append_data (wb, target->address.data.domain, dlen); break; } case SOCKS_IPV6: str_append_data (wb, target->address.data.ipv6, sizeof target->address.data.ipv6); break; } str_pack_u16 (wb, target->port); SOCKS_GO (socks_5_request_finish, 4); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SOCKS_DATA_CB (socks_5_userpass_finish) { uint8_t version, status; hard_assert (msg_unpacker_u8 (unpacker, &version)); hard_assert (msg_unpacker_u8 (unpacker, &status)); if (version != 0x01) SOCKS_FAIL ("protocol error"); if (status != 0x00) SOCKS_FAIL ("authentication failure"); return socks_5_request_start (self); } static bool socks_5_userpass_start (struct socks_connector *self) { size_t ulen = strlen (self->username); if (ulen > 255) ulen = 255; size_t plen = strlen (self->password); if (plen > 255) plen = 255; struct str *wb = &self->write_buffer; str_pack_u8 (wb, 0x01); // version str_pack_u8 (wb, ulen); // username length str_append_data (wb, self->username, ulen); str_pack_u8 (wb, plen); // password length str_append_data (wb, self->password, plen); SOCKS_GO (socks_5_userpass_finish, 2); } SOCKS_DATA_CB (socks_5_auth_finish) { uint8_t version, method; hard_assert (msg_unpacker_u8 (unpacker, &version)); hard_assert (msg_unpacker_u8 (unpacker, &method)); if (version != 0x05) SOCKS_FAIL ("protocol error"); bool can_auth = self->username && self->password; switch (method) { case 0x02: if (!can_auth) SOCKS_FAIL ("protocol error"); return socks_5_userpass_start (self); case 0x00: return socks_5_request_start (self); case 0xFF: SOCKS_FAIL ("no acceptable authentication methods"); default: SOCKS_FAIL ("protocol error"); } } static bool socks_5_auth_start (struct socks_connector *self) { bool can_auth = self->username && self->password; struct str *wb = &self->write_buffer; str_pack_u8 (wb, 0x05); // version str_pack_u8 (wb, 1 + can_auth); // number of authentication methods str_pack_u8 (wb, 0x00); // no authentication required if (can_auth) str_pack_u8 (wb, 0x02); // username/password SOCKS_GO (socks_5_auth_finish, 2); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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) { 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 // and just try to connect; this is done automatically by the connector // Then we iterate over available protocols if (++self->protocol_iter != SOCKS_MAX) return true; // At the highest level we iterate over possible targets self->protocol_iter = 0; if (self->targets_iter && (self->targets_iter = self->targets_iter->next)) return true; return false; } static void socks_connector_step (struct socks_connector *self) { if (self->socket_fd != -1) { poller_fd_reset (&self->socket_event); xclose (self->socket_fd); self->socket_fd = -1; } socks_connector_destroy_connector (self); if (socks_connector_step_iterators (self)) socks_connector_start (self); else socks_connector_fail (self); } static void 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); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - static void socks_connector_on_connected (void *user_data, int socket_fd, const char *hostname) { set_blocking (socket_fd, false); (void) hostname; struct socks_connector *self = user_data; self->socket_fd = socket_fd; self->socket_event.fd = socket_fd; poller_fd_set (&self->socket_event, POLLIN | POLLOUT); 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))) socks_connector_fail (self); } static void socks_connector_on_failure (void *user_data) { struct socks_connector *self = user_data; // TODO: skip SOCKS server on connection failure socks_connector_step (self); } static void socks_connector_on_connecting (void *user_data, const char *via) { struct socks_connector *self = user_data; if (!self->on_connecting) return; struct socks_target *target = self->targets_iter; char *port = xstrdup_printf ("%u", target->port); char *address = format_host_port_pair (target->address_str, port); free (port); self->on_connecting (self->user_data, address, via, socks_protocol_to_string (self->protocol_iter)); free (address); } static void socks_connector_on_error (void *user_data, const char *error) { struct socks_connector *self = user_data; // TODO: skip protocol on protocol failure if (self->on_error) self->on_error (self->user_data, error); } static void socks_connector_start (struct socks_connector *self) { hard_assert (!self->connector); struct connector *connector = self->connector = xcalloc (1, sizeof *connector); connector_init (connector, self->socket_event.poller); connector->user_data = self; connector->on_connected = socks_connector_on_connected; connector->on_connecting = socks_connector_on_connecting; connector->on_error = socks_connector_on_error; connector->on_failure = socks_connector_on_failure; connector_add_target (connector, self->hostname, self->service); poller_timer_set (&self->timeout, 60 * 1000); self->done = false; self->bound_port = 0; socks_addr_free (&self->bound_address); memset (&self->bound_address, 0, sizeof self->bound_address); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - static bool socks_try_fill_read_buffer (struct socks_connector *self, size_t n) { ssize_t remains = (ssize_t) n - (ssize_t) self->read_buffer.len; if (remains <= 0) return true; ssize_t received; str_reserve (&self->read_buffer, remains); do received = recv (self->socket_fd, self->read_buffer.str + self->read_buffer.len, remains, 0); while ((received == -1) && errno == EINTR); if (received == 0) SOCKS_FAIL ("%s: %s", "protocol error", "unexpected EOF"); if (received == -1 && errno != EAGAIN) SOCKS_FAIL ("%s: %s", "recv", strerror (errno)); if (received > 0) self->read_buffer.len += received; return true; } static bool socks_call_on_data (struct socks_connector *self) { size_t to_consume = self->data_needed; if (!socks_try_fill_read_buffer (self, to_consume)) return false; if (self->read_buffer.len < to_consume) return true; struct msg_unpacker unpacker = msg_unpacker_make (self->read_buffer.str, self->read_buffer.len); bool result = self->on_data (self, &unpacker); str_remove_slice (&self->read_buffer, 0, to_consume); return result; } static bool socks_try_flush_write_buffer (struct socks_connector *self) { struct str *wb = &self->write_buffer; ssize_t n_written; while (wb->len) { n_written = send (self->socket_fd, wb->str, wb->len, 0); if (n_written >= 0) { str_remove_slice (wb, 0, n_written); continue; } if (errno == EAGAIN) break; if (errno == EINTR) continue; SOCKS_FAIL ("%s: %s", "send", strerror (errno)); } return true; } static void socks_connector_on_ready (const struct pollfd *pfd, struct socks_connector *self) { (void) pfd; if (socks_call_on_data (self) && socks_try_flush_write_buffer (self)) { poller_fd_set (&self->socket_event, self->write_buffer.len ? (POLLIN | POLLOUT) : POLLIN); } else if (self->done) { socks_connector_cancel_events (self); int fd = self->socket_fd; self->socket_fd = -1; struct socks_target *target = self->targets_iter; set_blocking (fd, true); self->on_connected (self->user_data, fd, target->address_str); } else // We've failed this target, let's try to move on socks_connector_step (self); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - static void socks_connector_init (struct socks_connector *self, struct poller *poller) { memset (self, 0, sizeof *self); self->socket_event = poller_fd_make (poller, (self->socket_fd = -1)); self->socket_event.dispatcher = (poller_fd_fn) socks_connector_on_ready; self->socket_event.user_data = self; self->timeout = poller_timer_make (poller); self->timeout.dispatcher = (poller_timer_fn) socks_connector_on_timeout; self->timeout.user_data = self; self->read_buffer = str_make (); self->write_buffer = str_make (); } static void socks_connector_free (struct socks_connector *self) { socks_connector_destroy_connector (self); socks_connector_cancel_events (self); if (self->socket_fd != -1) xclose (self->socket_fd); str_free (&self->read_buffer); str_free (&self->write_buffer); free (self->hostname); free (self->service); free (self->username); free (self->password); LIST_FOR_EACH (struct socks_target, iter, self->targets) { socks_addr_free (&iter->address); free (iter->address_str); free (iter); } socks_addr_free (&self->bound_address); } static bool socks_connector_add_target (struct socks_connector *self, const char *host, const char *service, struct error **e) { unsigned long port; const struct servent *serv; if ((serv = getservbyname (service, "tcp"))) port = (uint16_t) ntohs (serv->s_port); else if (!xstrtoul (&port, service, 10) || !port || port > UINT16_MAX) { error_set (e, "invalid port number"); return false; } struct socks_target *target = xcalloc (1, sizeof *target); if (inet_pton (AF_INET, host, &target->address.data.ipv4) == 1) target->address.type = SOCKS_IPV4; else if (inet_pton (AF_INET6, host, &target->address.data.ipv6) == 1) target->address.type = SOCKS_IPV6; else { target->address.type = SOCKS_DOMAIN; target->address.data.domain = xstrdup (host); } target->port = port; target->address_str = xstrdup (host); LIST_APPEND_WITH_TAIL (self->targets, self->targets_tail, target); return true; } static void socks_connector_run (struct socks_connector *self, const char *host, const char *service, const char *username, const char *password) { hard_assert (self->targets); hard_assert (host && service); self->hostname = xstrdup (host); self->service = xstrdup (service); if (username) self->username = xstrdup (username); if (password) self->password = xstrdup (password); self->targets_iter = self->targets; self->protocol_iter = 0; // XXX: this can fail immediately from an error creating the connector socks_connector_start (self); } // --- CTCP decoding ----------------------------------------------------------- #define CTCP_M_QUOTE '\020' #define CTCP_X_DELIM '\001' #define CTCP_X_QUOTE '\\' struct ctcp_chunk { LIST_HEADER (struct ctcp_chunk) bool is_extended; ///< Is this a tagged extended message? bool is_partial; ///< Unterminated extended message struct str tag; ///< The tag, if any struct str text; ///< Message contents }; static struct ctcp_chunk * ctcp_chunk_new (void) { struct ctcp_chunk *self = xcalloc (1, sizeof *self); self->tag = str_make (); self->text = str_make (); return self; } static void ctcp_chunk_destroy (struct ctcp_chunk *self) { str_free (&self->tag); str_free (&self->text); free (self); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - static void ctcp_low_level_decode (const char *message, struct str *output) { bool escape = false; for (const char *p = message; *p; p++) { if (escape) { switch (*p) { case '0': str_append_c (output, '\0'); break; case 'r': str_append_c (output, '\r'); break; case 'n': str_append_c (output, '\n'); break; default: str_append_c (output, *p); } escape = false; } else if (*p == CTCP_M_QUOTE) escape = true; else str_append_c (output, *p); } } static void ctcp_intra_decode (const char *chunk, size_t len, struct str *output) { bool escape = false; for (size_t i = 0; i < len; i++) { char c = chunk[i]; if (escape) { if (c == 'a') str_append_c (output, CTCP_X_DELIM); else str_append_c (output, c); escape = false; } else if (c == CTCP_X_QUOTE) escape = true; else str_append_c (output, c); } } // According to the original CTCP specification we should use // ctcp_intra_decode() on all parts, however no one seems to use that // and it breaks normal text with backslashes #ifndef SUPPORT_CTCP_X_QUOTES #define ctcp_intra_decode(s, len, output) str_append_data (output, s, len) #endif static void ctcp_parse_tagged (const char *chunk, size_t len, struct ctcp_chunk *output) { // We may search for the space before doing the higher level decoding, // as it doesn't concern space characters at all size_t tag_end = len; for (size_t i = 0; i < len; i++) if (chunk[i] == ' ') { tag_end = i; break; } output->is_extended = true; ctcp_intra_decode (chunk, tag_end, &output->tag); if (tag_end++ != len) ctcp_intra_decode (chunk + tag_end, len - tag_end, &output->text); } static struct ctcp_chunk * ctcp_parse (const char *message) { struct str m = str_make (); ctcp_low_level_decode (message, &m); struct ctcp_chunk *result = NULL, *result_tail = NULL; size_t start = 0; bool in_ctcp = false; for (size_t i = 0; i < m.len; i++) { char c = m.str[i]; if (c != CTCP_X_DELIM) continue; // Remember the current state size_t my_start = start; bool my_is_ctcp = in_ctcp; start = i + 1; in_ctcp = !in_ctcp; // Skip empty chunks if (my_start == i) continue; struct ctcp_chunk *chunk = ctcp_chunk_new (); if (my_is_ctcp) ctcp_parse_tagged (m.str + my_start, i - my_start, chunk); else ctcp_intra_decode (m.str + my_start, i - my_start, &chunk->text); LIST_APPEND_WITH_TAIL (result, result_tail, chunk); } // Finish the last part. Unended tagged chunks are marked as such. if (start != m.len) { struct ctcp_chunk *chunk = ctcp_chunk_new (); if (in_ctcp) { ctcp_parse_tagged (m.str + start, m.len - start, chunk); chunk->is_partial = true; } else ctcp_intra_decode (m.str + start, m.len - start, &chunk->text); LIST_APPEND_WITH_TAIL (result, result_tail, chunk); } str_free (&m); return result; } static void ctcp_destroy (struct ctcp_chunk *list) { LIST_FOR_EACH (struct ctcp_chunk, iter, list) ctcp_chunk_destroy (iter); }