/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2013 David Strauss systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <errno.h> #include <getopt.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <netdb.h> #include <fcntl.h> #include <sys/socket.h> #include <sys/un.h> #include <unistd.h> #include "sd-daemon.h" #include "sd-event.h" #include "sd-resolve.h" #include "log.h" #include "socket-util.h" #include "util.h" #include "build.h" #include "set.h" #include "path-util.h" #define BUFFER_SIZE (256 * 1024) #define CONNECTIONS_MAX 256 static const char *arg_remote_host = NULL; typedef struct Context { sd_event *event; sd_resolve *resolve; Set *listen; Set *connections; } Context; typedef struct Connection { Context *context; int server_fd, client_fd; int server_to_client_buffer[2]; /* a pipe */ int client_to_server_buffer[2]; /* a pipe */ size_t server_to_client_buffer_full, client_to_server_buffer_full; size_t server_to_client_buffer_size, client_to_server_buffer_size; sd_event_source *server_event_source, *client_event_source; sd_resolve_query *resolve_query; } Connection; static void connection_free(Connection *c) { assert(c); if (c->context) set_remove(c->context->connections, c); sd_event_source_unref(c->server_event_source); sd_event_source_unref(c->client_event_source); safe_close(c->server_fd); safe_close(c->client_fd); safe_close_pair(c->server_to_client_buffer); safe_close_pair(c->client_to_server_buffer); sd_resolve_query_unref(c->resolve_query); free(c); } static void context_free(Context *context) { sd_event_source *es; Connection *c; assert(context); while ((es = set_steal_first(context->listen))) sd_event_source_unref(es); while ((c = set_first(context->connections))) connection_free(c); set_free(context->listen); set_free(context->connections); sd_event_unref(context->event); sd_resolve_unref(context->resolve); } static int connection_create_pipes(Connection *c, int buffer[2], size_t *sz) { int r; assert(c); assert(buffer); assert(sz); if (buffer[0] >= 0) return 0; r = pipe2(buffer, O_CLOEXEC|O_NONBLOCK); if (r < 0) return log_error_errno(errno, "Failed to allocate pipe buffer: %m"); (void) fcntl(buffer[0], F_SETPIPE_SZ, BUFFER_SIZE); r = fcntl(buffer[0], F_GETPIPE_SZ); if (r < 0) return log_error_errno(errno, "Failed to get pipe buffer size: %m"); assert(r > 0); *sz = r; return 0; } static int connection_shovel( Connection *c, int *from, int buffer[2], int *to, size_t *full, size_t *sz, sd_event_source **from_source, sd_event_source **to_source) { bool shoveled; assert(c); assert(from); assert(buffer); assert(buffer[0] >= 0); assert(buffer[1] >= 0); assert(to); assert(full); assert(sz); assert(from_source); assert(to_source); do { ssize_t z; shoveled = false; if (*full < *sz && *from >= 0 && *to >= 0) { z = splice(*from, NULL, buffer[1], NULL, *sz - *full, SPLICE_F_MOVE|SPLICE_F_NONBLOCK); if (z > 0) { *full += z; shoveled = true; } else if (z == 0 || errno == EPIPE || errno == ECONNRESET) { *from_source = sd_event_source_unref(*from_source); *from = safe_close(*from); } else if (errno != EAGAIN && errno != EINTR) return log_error_errno(errno, "Failed to splice: %m"); } if (*full > 0 && *to >= 0) { z = splice(buffer[0], NULL, *to, NULL, *full, SPLICE_F_MOVE|SPLICE_F_NONBLOCK); if (z > 0) { *full -= z; shoveled = true; } else if (z == 0 || errno == EPIPE || errno == ECONNRESET) { *to_source = sd_event_source_unref(*to_source); *to = safe_close(*to); } else if (errno != EAGAIN && errno != EINTR) return log_error_errno(errno, "Failed to splice: %m"); } } while (shoveled); return 0; } static int connection_enable_event_sources(Connection *c); static int traffic_cb(sd_event_source *s, int fd, uint32_t revents, void *userdata) { Connection *c = userdata; int r; assert(s); assert(fd >= 0); assert(c); r = connection_shovel(c, &c->server_fd, c->server_to_client_buffer, &c->client_fd, &c->server_to_client_buffer_full, &c->server_to_client_buffer_size, &c->server_event_source, &c->client_event_source); if (r < 0) goto quit; r = connection_shovel(c, &c->client_fd, c->client_to_server_buffer, &c->server_fd, &c->client_to_server_buffer_full, &c->client_to_server_buffer_size, &c->client_event_source, &c->server_event_source); if (r < 0) goto quit; /* EOF on both sides? */ if (c->server_fd == -1 && c->client_fd == -1) goto quit; /* Server closed, and all data written to client? */ if (c->server_fd == -1 && c->server_to_client_buffer_full <= 0) goto quit; /* Client closed, and all data written to server? */ if (c->client_fd == -1 && c->client_to_server_buffer_full <= 0) goto quit; r = connection_enable_event_sources(c); if (r < 0) goto quit; return 1; quit: connection_free(c); return 0; /* ignore errors, continue serving */ } static int connection_enable_event_sources(Connection *c) { uint32_t a = 0, b = 0; int r; assert(c); if (c->server_to_client_buffer_full > 0) b |= EPOLLOUT; if (c->server_to_client_buffer_full < c->server_to_client_buffer_size) a |= EPOLLIN; if (c->client_to_server_buffer_full > 0) a |= EPOLLOUT; if (c->client_to_server_buffer_full < c->client_to_server_buffer_size) b |= EPOLLIN; if (c->server_event_source) r = sd_event_source_set_io_events(c->server_event_source, a); else if (c->server_fd >= 0) r = sd_event_add_io(c->context->event, &c->server_event_source, c->server_fd, a, traffic_cb, c); else r = 0; if (r < 0) return log_error_errno(r, "Failed to set up server event source: %m"); if (c->client_event_source) r = sd_event_source_set_io_events(c->client_event_source, b); else if (c->client_fd >= 0) r = sd_event_add_io(c->context->event, &c->client_event_source, c->client_fd, b, traffic_cb, c); else r = 0; if (r < 0) return log_error_errno(r, "Failed to set up client event source: %m"); return 0; } static int connection_complete(Connection *c) { int r; assert(c); r = connection_create_pipes(c, c->server_to_client_buffer, &c->server_to_client_buffer_size); if (r < 0) goto fail; r = connection_create_pipes(c, c->client_to_server_buffer, &c->client_to_server_buffer_size); if (r < 0) goto fail; r = connection_enable_event_sources(c); if (r < 0) goto fail; return 0; fail: connection_free(c); return 0; /* ignore errors, continue serving */ } static int connect_cb(sd_event_source *s, int fd, uint32_t revents, void *userdata) { Connection *c = userdata; socklen_t solen; int error, r; assert(s); assert(fd >= 0); assert(c); solen = sizeof(error); r = getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &solen); if (r < 0) { log_error_errno(errno, "Failed to issue SO_ERROR: %m"); goto fail; } if (error != 0) { log_error_errno(error, "Failed to connect to remote host: %m"); goto fail; } c->client_event_source = sd_event_source_unref(c->client_event_source); return connection_complete(c); fail: connection_free(c); return 0; /* ignore errors, continue serving */ } static int connection_start(Connection *c, struct sockaddr *sa, socklen_t salen) { int r; assert(c); assert(sa); assert(salen); c->client_fd = socket(sa->sa_family, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0); if (c->client_fd < 0) { log_error_errno(errno, "Failed to get remote socket: %m"); goto fail; } r = connect(c->client_fd, sa, salen); if (r < 0) { if (errno == EINPROGRESS) { r = sd_event_add_io(c->context->event, &c->client_event_source, c->client_fd, EPOLLOUT, connect_cb, c); if (r < 0) { log_error_errno(r, "Failed to add connection socket: %m"); goto fail; } r = sd_event_source_set_enabled(c->client_event_source, SD_EVENT_ONESHOT); if (r < 0) { log_error_errno(r, "Failed to enable oneshot event source: %m"); goto fail; } } else { log_error_errno(errno, "Failed to connect to remote host: %m"); goto fail; } } else { r = connection_complete(c); if (r < 0) goto fail; } return 0; fail: connection_free(c); return 0; /* ignore errors, continue serving */ } static int resolve_cb(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) { Connection *c = userdata; assert(q); assert(c); if (ret != 0) { log_error("Failed to resolve host: %s", gai_strerror(ret)); goto fail; } c->resolve_query = sd_resolve_query_unref(c->resolve_query); return connection_start(c, ai->ai_addr, ai->ai_addrlen); fail: connection_free(c); return 0; /* ignore errors, continue serving */ } static int resolve_remote(Connection *c) { static const struct addrinfo hints = { .ai_family = AF_UNSPEC, .ai_socktype = SOCK_STREAM, .ai_flags = AI_ADDRCONFIG }; union sockaddr_union sa = {}; const char *node, *service; socklen_t salen; int r; if (path_is_absolute(arg_remote_host)) { sa.un.sun_family = AF_UNIX; strncpy(sa.un.sun_path, arg_remote_host, sizeof(sa.un.sun_path)-1); sa.un.sun_path[sizeof(sa.un.sun_path)-1] = 0; salen = offsetof(union sockaddr_union, un.sun_path) + strlen(sa.un.sun_path); return connection_start(c, &sa.sa, salen); } if (arg_remote_host[0] == '@') { sa.un.sun_family = AF_UNIX; sa.un.sun_path[0] = 0; strncpy(sa.un.sun_path+1, arg_remote_host+1, sizeof(sa.un.sun_path)-2); sa.un.sun_path[sizeof(sa.un.sun_path)-1] = 0; salen = offsetof(union sockaddr_union, un.sun_path) + 1 + strlen(sa.un.sun_path + 1); return connection_start(c, &sa.sa, salen); } service = strrchr(arg_remote_host, ':'); if (service) { node = strndupa(arg_remote_host, service - arg_remote_host); service ++; } else { node = arg_remote_host; service = "80"; } log_debug("Looking up address info for %s:%s", node, service); r = sd_resolve_getaddrinfo(c->context->resolve, &c->resolve_query, node, service, &hints, resolve_cb, c); if (r < 0) { log_error_errno(r, "Failed to resolve remote host: %m"); goto fail; } return 0; fail: connection_free(c); return 0; /* ignore errors, continue serving */ } static int add_connection_socket(Context *context, int fd) { Connection *c; int r; assert(context); assert(fd >= 0); if (set_size(context->connections) > CONNECTIONS_MAX) { log_warning("Hit connection limit, refusing connection."); safe_close(fd); return 0; } r = set_ensure_allocated(&context->connections, NULL); if (r < 0) { log_oom(); return 0; } c = new0(Connection, 1); if (!c) { log_oom(); return 0; } c->context = context; c->server_fd = fd; c->client_fd = -1; c->server_to_client_buffer[0] = c->server_to_client_buffer[1] = -1; c->client_to_server_buffer[0] = c->client_to_server_buffer[1] = -1; r = set_put(context->connections, c); if (r < 0) { free(c); log_oom(); return 0; } return resolve_remote(c); } static int accept_cb(sd_event_source *s, int fd, uint32_t revents, void *userdata) { _cleanup_free_ char *peer = NULL; Context *context = userdata; int nfd = -1, r; assert(s); assert(fd >= 0); assert(revents & EPOLLIN); assert(context); nfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); if (nfd < 0) { if (errno != -EAGAIN) log_warning_errno(errno, "Failed to accept() socket: %m"); } else { getpeername_pretty(nfd, &peer); log_debug("New connection from %s", strna(peer)); r = add_connection_socket(context, nfd); if (r < 0) { log_error_errno(r, "Failed to accept connection, ignoring: %m"); safe_close(fd); } } r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT); if (r < 0) { log_error_errno(r, "Error while re-enabling listener with ONESHOT: %m"); sd_event_exit(context->event, r); return r; } return 1; } static int add_listen_socket(Context *context, int fd) { sd_event_source *source; int r; assert(context); assert(fd >= 0); r = set_ensure_allocated(&context->listen, NULL); if (r < 0) { log_oom(); return r; } r = sd_is_socket(fd, 0, SOCK_STREAM, 1); if (r < 0) return log_error_errno(r, "Failed to determine socket type: %m"); if (r == 0) { log_error("Passed in socket is not a stream socket."); return -EINVAL; } r = fd_nonblock(fd, true); if (r < 0) return log_error_errno(r, "Failed to mark file descriptor non-blocking: %m"); r = sd_event_add_io(context->event, &source, fd, EPOLLIN, accept_cb, context); if (r < 0) return log_error_errno(r, "Failed to add event source: %m"); r = set_put(context->listen, source); if (r < 0) { log_error_errno(r, "Failed to add source to set: %m"); sd_event_source_unref(source); return r; } /* Set the watcher to oneshot in case other processes are also * watching to accept(). */ r = sd_event_source_set_enabled(source, SD_EVENT_ONESHOT); if (r < 0) return log_error_errno(r, "Failed to enable oneshot mode: %m"); return 0; } static void help(void) { printf("%1$s [HOST:PORT]\n" "%1$s [SOCKET]\n\n" "Bidirectionally proxy local sockets to another (possibly remote) socket.\n\n" " -h --help Show this help\n" " --version Show package version\n", program_invocation_short_name); } static int parse_argv(int argc, char *argv[]) { enum { ARG_VERSION = 0x100, ARG_IGNORE_ENV }; static const struct option options[] = { { "help", no_argument, NULL, 'h' }, { "version", no_argument, NULL, ARG_VERSION }, {} }; int c; assert(argc >= 0); assert(argv); while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) switch (c) { case 'h': help(); return 0; case ARG_VERSION: puts(PACKAGE_STRING); puts(SYSTEMD_FEATURES); return 0; case '?': return -EINVAL; default: assert_not_reached("Unhandled option"); } if (optind >= argc) { log_error("Not enough parameters."); return -EINVAL; } if (argc != optind+1) { log_error("Too many parameters."); return -EINVAL; } arg_remote_host = argv[optind]; return 1; } int main(int argc, char *argv[]) { Context context = {}; int r, n, fd; log_parse_environment(); log_open(); r = parse_argv(argc, argv); if (r <= 0) goto finish; r = sd_event_default(&context.event); if (r < 0) { log_error_errno(r, "Failed to allocate event loop: %m"); goto finish; } r = sd_resolve_default(&context.resolve); if (r < 0) { log_error_errno(r, "Failed to allocate resolver: %m"); goto finish; } r = sd_resolve_attach_event(context.resolve, context.event, 0); if (r < 0) { log_error_errno(r, "Failed to attach resolver: %m"); goto finish; } sd_event_set_watchdog(context.event, true); n = sd_listen_fds(1); if (n < 0) { log_error("Failed to receive sockets from parent."); r = n; goto finish; } else if (n == 0) { log_error("Didn't get any sockets passed in."); r = -EINVAL; goto finish; } for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) { r = add_listen_socket(&context, fd); if (r < 0) goto finish; } r = sd_event_loop(context.event); if (r < 0) { log_error_errno(r, "Failed to run event loop: %m"); goto finish; } finish: context_free(&context); return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; }