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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
commit | 19f4f86bfed21c5326ed2acebe1163f3a83e832b (patch) | |
tree | d59b9989ce55ed23693e80974d94c856f1c2c8b1 /src/socket-proxy | |
parent | Initial commit. (diff) | |
download | systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.tar.xz systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.zip |
Adding upstream version 241.upstream/241upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/socket-proxy')
-rw-r--r-- | src/socket-proxy/socket-proxyd.c | 665 |
1 files changed, 665 insertions, 0 deletions
diff --git a/src/socket-proxy/socket-proxyd.c b/src/socket-proxy/socket-proxyd.c new file mode 100644 index 0000000..bac5c16 --- /dev/null +++ b/src/socket-proxy/socket-proxyd.c @@ -0,0 +1,665 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <errno.h> +#include <fcntl.h> +#include <getopt.h> +#include <netdb.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.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 "alloc-util.h" +#include "fd-util.h" +#include "log.h" +#include "main-func.h" +#include "parse-util.h" +#include "path-util.h" +#include "pretty-print.h" +#include "resolve-private.h" +#include "set.h" +#include "socket-util.h" +#include "string-util.h" +#include "util.h" + +#define BUFFER_SIZE (256 * 1024) +static unsigned arg_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_clear(Context *context) { + assert(context); + + set_free_with_destructor(context->listen, sd_event_source_unref); + set_free_with_destructor(context->connections, connection_free); + + sd_event_unref(context->event); + sd_resolve_unref(context->resolve); +} + +static int connection_create_pipes(Connection *c, int buffer[static 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 || IN_SET(errno, EPIPE, ECONNRESET)) { + *from_source = sd_event_source_unref(*from_source); + *from = safe_close(*from); + } else if (!IN_SET(errno, EAGAIN, 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 || IN_SET(errno, EPIPE, ECONNRESET)) { + *to_source = sd_event_source_unref(*to_source); + *to = safe_close(*to); + } else if (!IN_SET(errno, EAGAIN, 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_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, Connection *c) { + 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; + int r; + + if (IN_SET(arg_remote_host[0], '/', '@')) { + int salen; + + salen = sockaddr_un_set_path(&sa.un, arg_remote_host); + if (salen < 0) { + log_error_errno(salen, "Specified address doesn't fit in an AF_UNIX address, refusing: %m"); + goto fail; + } + + 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 = resolve_getaddrinfo(c->context->resolve, &c->resolve_query, node, service, &hints, resolve_handler, NULL, 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) > arg_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, true, &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) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Passed in socket is not a stream socket."); + + 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 int help(void) { + _cleanup_free_ char *link = NULL; + int r; + + r = terminal_urlify_man("systemd-socket-proxyd", "8", &link); + if (r < 0) + return log_oom(); + + printf("%1$s [HOST:PORT]\n" + "%1$s [SOCKET]\n\n" + "Bidirectionally proxy local sockets to another (possibly remote) socket.\n\n" + " -c --connections-max= Set the maximum number of connections to be accepted\n" + " -h --help Show this help\n" + " --version Show package version\n" + "\nSee the %2$s for details.\n" + , program_invocation_short_name + , link + ); + + return 0; +} + +static int parse_argv(int argc, char *argv[]) { + + enum { + ARG_VERSION = 0x100, + ARG_IGNORE_ENV + }; + + static const struct option options[] = { + { "connections-max", required_argument, NULL, 'c' }, + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, ARG_VERSION }, + {} + }; + + int c, r; + + assert(argc >= 0); + assert(argv); + + while ((c = getopt_long(argc, argv, "c:h", options, NULL)) >= 0) + + switch (c) { + + case 'h': + return help(); + + case ARG_VERSION: + return version(); + + case 'c': + r = safe_atou(optarg, &arg_connections_max); + if (r < 0) { + log_error("Failed to parse --connections-max= argument: %s", optarg); + return r; + } + + if (arg_connections_max < 1) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Connection limit is too low."); + + break; + + case '?': + return -EINVAL; + + default: + assert_not_reached("Unhandled option"); + } + + if (optind >= argc) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Not enough parameters."); + + if (argc != optind+1) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Too many parameters."); + + arg_remote_host = argv[optind]; + return 1; +} + +static int run(int argc, char *argv[]) { + _cleanup_(context_clear) Context context = {}; + int r, n, fd; + + log_parse_environment(); + log_open(); + + r = parse_argv(argc, argv); + if (r <= 0) + return r; + + r = sd_event_default(&context.event); + if (r < 0) + return log_error_errno(r, "Failed to allocate event loop: %m"); + + r = sd_resolve_default(&context.resolve); + if (r < 0) + return log_error_errno(r, "Failed to allocate resolver: %m"); + + r = sd_resolve_attach_event(context.resolve, context.event, 0); + if (r < 0) + return log_error_errno(r, "Failed to attach resolver: %m"); + + sd_event_set_watchdog(context.event, true); + + r = sd_listen_fds(1); + if (r < 0) + return log_error_errno(r, "Failed to receive sockets from parent."); + if (r == 0) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Didn't get any sockets passed in."); + + n = r; + + for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) { + r = add_listen_socket(&context, fd); + if (r < 0) + return r; + } + + r = sd_event_loop(context.event); + if (r < 0) + return log_error_errno(r, "Failed to run event loop: %m"); + + return 0; +} + +DEFINE_MAIN_FUNCTION(run); |