1 /* SPDX-License-Identifier: LGPL-2.1+ */
10 #include <sys/socket.h>
14 #include "sd-daemon.h"
16 #include "sd-resolve.h"
18 #include "alloc-util.h"
21 #include "parse-util.h"
22 #include "path-util.h"
24 #include "socket-util.h"
25 #include "string-util.h"
26 #include "terminal-util.h"
29 #define BUFFER_SIZE (256 * 1024)
30 static unsigned arg_connections_max
= 256;
32 static const char *arg_remote_host
= NULL
;
34 typedef struct Context
{
42 typedef struct Connection
{
45 int server_fd
, client_fd
;
46 int server_to_client_buffer
[2]; /* a pipe */
47 int client_to_server_buffer
[2]; /* a pipe */
49 size_t server_to_client_buffer_full
, client_to_server_buffer_full
;
50 size_t server_to_client_buffer_size
, client_to_server_buffer_size
;
52 sd_event_source
*server_event_source
, *client_event_source
;
54 sd_resolve_query
*resolve_query
;
57 static void connection_free(Connection
*c
) {
61 set_remove(c
->context
->connections
, c
);
63 sd_event_source_unref(c
->server_event_source
);
64 sd_event_source_unref(c
->client_event_source
);
66 safe_close(c
->server_fd
);
67 safe_close(c
->client_fd
);
69 safe_close_pair(c
->server_to_client_buffer
);
70 safe_close_pair(c
->client_to_server_buffer
);
72 sd_resolve_query_unref(c
->resolve_query
);
77 static void context_free(Context
*context
) {
80 set_free_with_destructor(context
->listen
, sd_event_source_unref
);
81 set_free_with_destructor(context
->connections
, connection_free
);
83 sd_event_unref(context
->event
);
84 sd_resolve_unref(context
->resolve
);
87 static int connection_create_pipes(Connection
*c
, int buffer
[2], size_t *sz
) {
97 r
= pipe2(buffer
, O_CLOEXEC
|O_NONBLOCK
);
99 return log_error_errno(errno
, "Failed to allocate pipe buffer: %m");
101 (void) fcntl(buffer
[0], F_SETPIPE_SZ
, BUFFER_SIZE
);
103 r
= fcntl(buffer
[0], F_GETPIPE_SZ
);
105 return log_error_errno(errno
, "Failed to get pipe buffer size: %m");
113 static int connection_shovel(
115 int *from
, int buffer
[2], int *to
,
116 size_t *full
, size_t *sz
,
117 sd_event_source
**from_source
, sd_event_source
**to_source
) {
124 assert(buffer
[0] >= 0);
125 assert(buffer
[1] >= 0);
137 if (*full
< *sz
&& *from
>= 0 && *to
>= 0) {
138 z
= splice(*from
, NULL
, buffer
[1], NULL
, *sz
- *full
, SPLICE_F_MOVE
|SPLICE_F_NONBLOCK
);
142 } else if (z
== 0 || IN_SET(errno
, EPIPE
, ECONNRESET
)) {
143 *from_source
= sd_event_source_unref(*from_source
);
144 *from
= safe_close(*from
);
145 } else if (!IN_SET(errno
, EAGAIN
, EINTR
))
146 return log_error_errno(errno
, "Failed to splice: %m");
149 if (*full
> 0 && *to
>= 0) {
150 z
= splice(buffer
[0], NULL
, *to
, NULL
, *full
, SPLICE_F_MOVE
|SPLICE_F_NONBLOCK
);
154 } else if (z
== 0 || IN_SET(errno
, EPIPE
, ECONNRESET
)) {
155 *to_source
= sd_event_source_unref(*to_source
);
156 *to
= safe_close(*to
);
157 } else if (!IN_SET(errno
, EAGAIN
, EINTR
))
158 return log_error_errno(errno
, "Failed to splice: %m");
165 static int connection_enable_event_sources(Connection
*c
);
167 static int traffic_cb(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
168 Connection
*c
= userdata
;
175 r
= connection_shovel(c
,
176 &c
->server_fd
, c
->server_to_client_buffer
, &c
->client_fd
,
177 &c
->server_to_client_buffer_full
, &c
->server_to_client_buffer_size
,
178 &c
->server_event_source
, &c
->client_event_source
);
182 r
= connection_shovel(c
,
183 &c
->client_fd
, c
->client_to_server_buffer
, &c
->server_fd
,
184 &c
->client_to_server_buffer_full
, &c
->client_to_server_buffer_size
,
185 &c
->client_event_source
, &c
->server_event_source
);
189 /* EOF on both sides? */
190 if (c
->server_fd
== -1 && c
->client_fd
== -1)
193 /* Server closed, and all data written to client? */
194 if (c
->server_fd
== -1 && c
->server_to_client_buffer_full
<= 0)
197 /* Client closed, and all data written to server? */
198 if (c
->client_fd
== -1 && c
->client_to_server_buffer_full
<= 0)
201 r
= connection_enable_event_sources(c
);
209 return 0; /* ignore errors, continue serving */
212 static int connection_enable_event_sources(Connection
*c
) {
213 uint32_t a
= 0, b
= 0;
218 if (c
->server_to_client_buffer_full
> 0)
220 if (c
->server_to_client_buffer_full
< c
->server_to_client_buffer_size
)
223 if (c
->client_to_server_buffer_full
> 0)
225 if (c
->client_to_server_buffer_full
< c
->client_to_server_buffer_size
)
228 if (c
->server_event_source
)
229 r
= sd_event_source_set_io_events(c
->server_event_source
, a
);
230 else if (c
->server_fd
>= 0)
231 r
= sd_event_add_io(c
->context
->event
, &c
->server_event_source
, c
->server_fd
, a
, traffic_cb
, c
);
236 return log_error_errno(r
, "Failed to set up server event source: %m");
238 if (c
->client_event_source
)
239 r
= sd_event_source_set_io_events(c
->client_event_source
, b
);
240 else if (c
->client_fd
>= 0)
241 r
= sd_event_add_io(c
->context
->event
, &c
->client_event_source
, c
->client_fd
, b
, traffic_cb
, c
);
246 return log_error_errno(r
, "Failed to set up client event source: %m");
251 static int connection_complete(Connection
*c
) {
256 r
= connection_create_pipes(c
, c
->server_to_client_buffer
, &c
->server_to_client_buffer_size
);
260 r
= connection_create_pipes(c
, c
->client_to_server_buffer
, &c
->client_to_server_buffer_size
);
264 r
= connection_enable_event_sources(c
);
272 return 0; /* ignore errors, continue serving */
275 static int connect_cb(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
276 Connection
*c
= userdata
;
284 solen
= sizeof(error
);
285 r
= getsockopt(fd
, SOL_SOCKET
, SO_ERROR
, &error
, &solen
);
287 log_error_errno(errno
, "Failed to issue SO_ERROR: %m");
292 log_error_errno(error
, "Failed to connect to remote host: %m");
296 c
->client_event_source
= sd_event_source_unref(c
->client_event_source
);
298 return connection_complete(c
);
302 return 0; /* ignore errors, continue serving */
305 static int connection_start(Connection
*c
, struct sockaddr
*sa
, socklen_t salen
) {
312 c
->client_fd
= socket(sa
->sa_family
, SOCK_STREAM
|SOCK_NONBLOCK
|SOCK_CLOEXEC
, 0);
313 if (c
->client_fd
< 0) {
314 log_error_errno(errno
, "Failed to get remote socket: %m");
318 r
= connect(c
->client_fd
, sa
, salen
);
320 if (errno
== EINPROGRESS
) {
321 r
= sd_event_add_io(c
->context
->event
, &c
->client_event_source
, c
->client_fd
, EPOLLOUT
, connect_cb
, c
);
323 log_error_errno(r
, "Failed to add connection socket: %m");
327 r
= sd_event_source_set_enabled(c
->client_event_source
, SD_EVENT_ONESHOT
);
329 log_error_errno(r
, "Failed to enable oneshot event source: %m");
333 log_error_errno(errno
, "Failed to connect to remote host: %m");
337 r
= connection_complete(c
);
346 return 0; /* ignore errors, continue serving */
349 static int resolve_cb(sd_resolve_query
*q
, int ret
, const struct addrinfo
*ai
, void *userdata
) {
350 Connection
*c
= userdata
;
356 log_error("Failed to resolve host: %s", gai_strerror(ret
));
360 c
->resolve_query
= sd_resolve_query_unref(c
->resolve_query
);
362 return connection_start(c
, ai
->ai_addr
, ai
->ai_addrlen
);
366 return 0; /* ignore errors, continue serving */
369 static int resolve_remote(Connection
*c
) {
371 static const struct addrinfo hints
= {
372 .ai_family
= AF_UNSPEC
,
373 .ai_socktype
= SOCK_STREAM
,
374 .ai_flags
= AI_ADDRCONFIG
377 union sockaddr_union sa
= {};
378 const char *node
, *service
;
381 if (path_is_absolute(arg_remote_host
)) {
382 sa
.un
.sun_family
= AF_UNIX
;
383 strncpy(sa
.un
.sun_path
, arg_remote_host
, sizeof(sa
.un
.sun_path
));
384 return connection_start(c
, &sa
.sa
, SOCKADDR_UN_LEN(sa
.un
));
387 if (arg_remote_host
[0] == '@') {
388 sa
.un
.sun_family
= AF_UNIX
;
389 sa
.un
.sun_path
[0] = 0;
390 strncpy(sa
.un
.sun_path
+1, arg_remote_host
+1, sizeof(sa
.un
.sun_path
)-1);
391 return connection_start(c
, &sa
.sa
, SOCKADDR_UN_LEN(sa
.un
));
394 service
= strrchr(arg_remote_host
, ':');
396 node
= strndupa(arg_remote_host
, service
- arg_remote_host
);
399 node
= arg_remote_host
;
403 log_debug("Looking up address info for %s:%s", node
, service
);
404 r
= sd_resolve_getaddrinfo(c
->context
->resolve
, &c
->resolve_query
, node
, service
, &hints
, resolve_cb
, c
);
406 log_error_errno(r
, "Failed to resolve remote host: %m");
414 return 0; /* ignore errors, continue serving */
417 static int add_connection_socket(Context
*context
, int fd
) {
424 if (set_size(context
->connections
) > arg_connections_max
) {
425 log_warning("Hit connection limit, refusing connection.");
430 r
= set_ensure_allocated(&context
->connections
, NULL
);
436 c
= new0(Connection
, 1);
442 c
->context
= context
;
445 c
->server_to_client_buffer
[0] = c
->server_to_client_buffer
[1] = -1;
446 c
->client_to_server_buffer
[0] = c
->client_to_server_buffer
[1] = -1;
448 r
= set_put(context
->connections
, c
);
455 return resolve_remote(c
);
458 static int accept_cb(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
459 _cleanup_free_
char *peer
= NULL
;
460 Context
*context
= userdata
;
465 assert(revents
& EPOLLIN
);
468 nfd
= accept4(fd
, NULL
, NULL
, SOCK_NONBLOCK
|SOCK_CLOEXEC
);
470 if (errno
!= -EAGAIN
)
471 log_warning_errno(errno
, "Failed to accept() socket: %m");
473 getpeername_pretty(nfd
, true, &peer
);
474 log_debug("New connection from %s", strna(peer
));
476 r
= add_connection_socket(context
, nfd
);
478 log_error_errno(r
, "Failed to accept connection, ignoring: %m");
483 r
= sd_event_source_set_enabled(s
, SD_EVENT_ONESHOT
);
485 log_error_errno(r
, "Error while re-enabling listener with ONESHOT: %m");
486 sd_event_exit(context
->event
, r
);
493 static int add_listen_socket(Context
*context
, int fd
) {
494 sd_event_source
*source
;
500 r
= set_ensure_allocated(&context
->listen
, NULL
);
506 r
= sd_is_socket(fd
, 0, SOCK_STREAM
, 1);
508 return log_error_errno(r
, "Failed to determine socket type: %m");
510 log_error("Passed in socket is not a stream socket.");
514 r
= fd_nonblock(fd
, true);
516 return log_error_errno(r
, "Failed to mark file descriptor non-blocking: %m");
518 r
= sd_event_add_io(context
->event
, &source
, fd
, EPOLLIN
, accept_cb
, context
);
520 return log_error_errno(r
, "Failed to add event source: %m");
522 r
= set_put(context
->listen
, source
);
524 log_error_errno(r
, "Failed to add source to set: %m");
525 sd_event_source_unref(source
);
529 /* Set the watcher to oneshot in case other processes are also
530 * watching to accept(). */
531 r
= sd_event_source_set_enabled(source
, SD_EVENT_ONESHOT
);
533 return log_error_errno(r
, "Failed to enable oneshot mode: %m");
538 static int help(void) {
539 _cleanup_free_
char *link
= NULL
;
542 r
= terminal_urlify_man("systemd-socket-proxyd", "8", &link
);
546 printf("%1$s [HOST:PORT]\n"
548 "Bidirectionally proxy local sockets to another (possibly remote) socket.\n\n"
549 " -c --connections-max= Set the maximum number of connections to be accepted\n"
550 " -h --help Show this help\n"
551 " --version Show package version\n"
552 "\nSee the %2$s for details.\n"
553 , program_invocation_short_name
560 static int parse_argv(int argc
, char *argv
[]) {
567 static const struct option options
[] = {
568 { "connections-max", required_argument
, NULL
, 'c' },
569 { "help", no_argument
, NULL
, 'h' },
570 { "version", no_argument
, NULL
, ARG_VERSION
},
579 while ((c
= getopt_long(argc
, argv
, "c:h", options
, NULL
)) >= 0)
590 r
= safe_atou(optarg
, &arg_connections_max
);
592 log_error("Failed to parse --connections-max= argument: %s", optarg
);
596 if (arg_connections_max
< 1) {
597 log_error("Connection limit is too low.");
607 assert_not_reached("Unhandled option");
610 if (optind
>= argc
) {
611 log_error("Not enough parameters.");
615 if (argc
!= optind
+1) {
616 log_error("Too many parameters.");
620 arg_remote_host
= argv
[optind
];
624 int main(int argc
, char *argv
[]) {
625 Context context
= {};
628 log_parse_environment();
631 r
= parse_argv(argc
, argv
);
635 r
= sd_event_default(&context
.event
);
637 log_error_errno(r
, "Failed to allocate event loop: %m");
641 r
= sd_resolve_default(&context
.resolve
);
643 log_error_errno(r
, "Failed to allocate resolver: %m");
647 r
= sd_resolve_attach_event(context
.resolve
, context
.event
, 0);
649 log_error_errno(r
, "Failed to attach resolver: %m");
653 sd_event_set_watchdog(context
.event
, true);
655 n
= sd_listen_fds(1);
657 log_error("Failed to receive sockets from parent.");
661 log_error("Didn't get any sockets passed in.");
666 for (fd
= SD_LISTEN_FDS_START
; fd
< SD_LISTEN_FDS_START
+ n
; fd
++) {
667 r
= add_listen_socket(&context
, fd
);
672 r
= sd_event_loop(context
.event
);
674 log_error_errno(r
, "Failed to run event loop: %m");
679 context_free(&context
);
681 return r
< 0 ? EXIT_FAILURE
: EXIT_SUCCESS
;