diff options
Diffstat (limited to 'bin/relay.c')
-rw-r--r-- | bin/relay.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/bin/relay.c b/bin/relay.c new file mode 100644 index 00000000..fd799462 --- /dev/null +++ b/bin/relay.c @@ -0,0 +1,218 @@ +/* Copyright (C) 2019 June McEnroe <june@causal.agency> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Additional permission under GNU GPL version 3 section 7: + * + * If you modify this Program, or any covered work, by linking or + * combining it with LibreSSL (or a modified version of that library), + * containing parts covered by the terms of the OpenSSL License and the + * original SSLeay license, the licensors of this Program grant you + * additional permission to convey the resulting work. Corresponding + * Source for a non-source form of such a combination shall include the + * source code for the parts of LibreSSL used as well as that of the + * covered work. + */ + +#include <err.h> +#include <netdb.h> +#include <netinet/in.h> +#include <poll.h> +#include <signal.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/socket.h> +#include <sysexits.h> +#include <tls.h> +#include <unistd.h> + +#ifdef __FreeBSD__ +#include <sys/capsicum.h> +#endif + +static void clientWrite(struct tls *client, const char *ptr, size_t len) { + while (len) { + ssize_t ret = tls_write(client, ptr, len); + if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) continue; + if (ret < 0) errx(EX_IOERR, "tls_write: %s", tls_error(client)); + ptr += ret; + len -= ret; + } +} + +static void clientFormat(struct tls *client, const char *format, ...) { + char buf[1024]; + va_list ap; + va_start(ap, format); + int len = vsnprintf(buf, sizeof(buf), format, ap); + va_end(ap); + if ((size_t)len > sizeof(buf) - 1) errx(EX_DATAERR, "message too large"); + clientWrite(client, buf, len); +} + +static void clientHandle(struct tls *client, const char *chan, char *line) { + char *prefix = NULL; + if (line[0] == ':') { + prefix = strsep(&line, " ") + 1; + if (!line) errx(EX_PROTOCOL, "unexpected eol"); + } + + char *command = strsep(&line, " "); + if (!strcmp(command, "001") || !strcmp(command, "INVITE")) { + clientFormat(client, "JOIN :%s\r\n", chan); + } else if (!strcmp(command, "PING")) { + clientFormat(client, "PONG %s\r\n", line); + } + if (strcmp(command, "PRIVMSG") && strcmp(command, "NOTICE")) return; + + if (!prefix) errx(EX_PROTOCOL, "message without prefix"); + char *nick = strsep(&prefix, "!"); + + if (!line) errx(EX_PROTOCOL, "message without destination"); + char *dest = strsep(&line, " "); + if (strcmp(dest, chan)) return; + + if (!line || line[0] != ':') errx(EX_PROTOCOL, "message without message"); + line = &line[1]; + + if (!strncmp(line, "\1ACTION ", 8)) { + line = &line[8]; + size_t len = strcspn(line, "\1"); + printf("* %c\u200C%s %.*s\n", nick[0], &nick[1], (int)len, line); + } else if (command[0] == 'N') { + printf("-%c\u200C%s- %s\n", nick[0], &nick[1], line); + } else { + printf("<%c\u200C%s> %s\n", nick[0], &nick[1], line); + } +} + +#ifdef __FreeBSD__ +static void limit(int fd, const cap_rights_t *rights) { + int error = cap_rights_limit(fd, rights); + if (error) err(EX_OSERR, "cap_rights_limit"); +} +#endif + +int main(int argc, char *argv[]) { + int error; + + if (argc < 5) return EX_USAGE; + const char *host = argv[1]; + const char *port = argv[2]; + const char *nick = argv[3]; + const char *chan = argv[4]; + + setlinebuf(stdout); + signal(SIGPIPE, SIG_IGN); + + struct tls_config *config = tls_config_new(); + if (!config) errx(EX_SOFTWARE, "tls_config_new"); + + error = tls_config_set_ciphers(config, "compat"); + if (error) { + errx(EX_SOFTWARE, "tls_config_set_ciphers: %s", tls_config_error(config)); + } + + struct tls *client = tls_client(); + if (!client) errx(EX_SOFTWARE, "tls_client"); + + error = tls_configure(client, config); + if (error) errx(EX_SOFTWARE, "tls_configure: %s", tls_error(client)); + tls_config_free(config); + + struct addrinfo *head; + struct addrinfo hints = { + .ai_family = AF_UNSPEC, + .ai_socktype = SOCK_STREAM, + .ai_protocol = IPPROTO_TCP, + }; + error = getaddrinfo(host, port, &hints, &head); + if (error) errx(EX_NOHOST, "getaddrinfo: %s", gai_strerror(error)); + + int sock = -1; + for (struct addrinfo *ai = head; ai; ai = ai->ai_next) { + sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); + if (sock < 0) err(EX_OSERR, "socket"); + + error = connect(sock, ai->ai_addr, ai->ai_addrlen); + if (!error) break; + + close(sock); + sock = -1; + } + if (sock < 0) err(EX_UNAVAILABLE, "connect"); + freeaddrinfo(head); + + error = tls_connect_socket(client, sock, host); + if (error) errx(EX_PROTOCOL, "tls_connect: %s", tls_error(client)); + +#ifdef __FreeBSD__ + error = cap_enter(); + if (error) err(EX_OSERR, "cap_enter"); + + cap_rights_t rights; + cap_rights_init(&rights, CAP_WRITE); + limit(STDOUT_FILENO, &rights); + limit(STDERR_FILENO, &rights); + + cap_rights_init(&rights, CAP_EVENT, CAP_READ); + limit(STDIN_FILENO, &rights); + + cap_rights_set(&rights, CAP_WRITE); + limit(sock, &rights); +#endif + + clientFormat(client, "NICK :%s\r\nUSER %s 0 * :%s\r\n", nick, nick, nick); + + char *input = NULL; + size_t cap = 0; + + char buf[4096]; + size_t len = 0; + + struct pollfd fds[2] = { + { .events = POLLIN, .fd = STDIN_FILENO }, + { .events = POLLIN, .fd = sock }, + }; + while (0 < poll(fds, 2, -1)) { + if (fds[0].revents) { + ssize_t len = getline(&input, &cap, stdin); + if (len < 0) err(EX_IOERR, "getline"); + input[len - 1] = '\0'; + clientFormat(client, "NOTICE %s :%s\r\n", chan, input); + } + if (!fds[1].revents) continue; + + ssize_t read = tls_read(client, &buf[len], sizeof(buf) - len); + if (read == TLS_WANT_POLLIN || read == TLS_WANT_POLLOUT) continue; + if (read < 0) errx(EX_IOERR, "tls_read: %s", tls_error(client)); + if (!read) return EX_UNAVAILABLE; + len += read; + + char *crlf; + char *line = buf; + for (;;) { + crlf = memmem(line, &buf[len] - line, "\r\n", 2); + if (!crlf) break; + crlf[0] = '\0'; + clientHandle(client, chan, line); + line = &crlf[2]; + } + len -= line - buf; + memmove(buf, line, len); + } + err(EX_IOERR, "poll"); +} |