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 "path-util.h"
23 #include "socket-util.h"
24 #include "string-util.h"
25 #include "parse-util.h"
28 #define BUFFER_SIZE (256 * 1024)
29 static unsigned arg_connections_max
= 256;
31 static const char *arg_remote_host
= NULL
;
33 typedef struct Context
{
41 typedef struct Connection
{
44 int server_fd
, client_fd
;
45 int server_to_client_buffer
[2]; /* a pipe */
46 int client_to_server_buffer
[2]; /* a pipe */
48 size_t server_to_client_buffer_full
, client_to_server_buffer_full
;
49 size_t server_to_client_buffer_size
, client_to_server_buffer_size
;
51 sd_event_source
*server_event_source
, *client_event_source
;
53 sd_resolve_query
*resolve_query
;
56 static void connection_free(Connection
*c
) {
60 set_remove(c
->context
->connections
, c
);
62 sd_event_source_unref(c
->server_event_source
);
63 sd_event_source_unref(c
->client_event_source
);
65 safe_close(c
->server_fd
);
66 safe_close(c
->client_fd
);
68 safe_close_pair(c
->server_to_client_buffer
);
69 safe_close_pair(c
->client_to_server_buffer
);
71 sd_resolve_query_unref(c
->resolve_query
);
76 static void context_free(Context
*context
) {
79 set_free_with_destructor(context
->listen
, sd_event_source_unref
);
80 set_free_with_destructor(context
->connections
, connection_free
);
82 sd_event_unref(context
->event
);
83 sd_resolve_unref(context
->resolve
);
86 static int connection_create_pipes(Connection
*c
, int buffer
[2], size_t *sz
) {
96 r
= pipe2(buffer
, O_CLOEXEC
|O_NONBLOCK
);
98 return log_error_errno(errno
, "Failed to allocate pipe buffer: %m");
100 (void) fcntl(buffer
[0], F_SETPIPE_SZ
, BUFFER_SIZE
);
102 r
= fcntl(buffer
[0], F_GETPIPE_SZ
);
104 return log_error_errno(errno
, "Failed to get pipe buffer size: %m");
112 static int connection_shovel(
114 int *from
, int buffer
[2], int *to
,
115 size_t *full
, size_t *sz
,
116 sd_event_source
**from_source
, sd_event_source
**to_source
) {
123 assert(buffer
[0] >= 0);
124 assert(buffer
[1] >= 0);
136 if (*full
< *sz
&& *from
>= 0 && *to
>= 0) {
137 z
= splice(*from
, NULL
, buffer
[1], NULL
, *sz
- *full
, SPLICE_F_MOVE
|SPLICE_F_NONBLOCK
);
141 } else if (z
== 0 || IN_SET(errno
, EPIPE
, ECONNRESET
)) {
142 *from_source
= sd_event_source_unref(*from_source
);
143 *from
= safe_close(*from
);
144 } else if (!IN_SET(errno
, EAGAIN
, EINTR
))
145 return log_error_errno(errno
, "Failed to splice: %m");
148 if (*full
> 0 && *to
>= 0) {
149 z
= splice(buffer
[0], NULL
, *to
, NULL
, *full
, SPLICE_F_MOVE
|SPLICE_F_NONBLOCK
);
153 } else if (z
== 0 || IN_SET(errno
, EPIPE
, ECONNRESET
)) {
154 *to_source
= sd_event_source_unref(*to_source
);
155 *to
= safe_close(*to
);
156 } else if (!IN_SET(errno
, EAGAIN
, EINTR
))
157 return log_error_errno(errno
, "Failed to splice: %m");
164 static int connection_enable_event_sources(Connection
*c
);
166 static int traffic_cb(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
167 Connection
*c
= userdata
;
174 r
= connection_shovel(c
,
175 &c
->server_fd
, c
->server_to_client_buffer
, &c
->client_fd
,
176 &c
->server_to_client_buffer_full
, &c
->server_to_client_buffer_size
,
177 &c
->server_event_source
, &c
->client_event_source
);
181 r
= connection_shovel(c
,
182 &c
->client_fd
, c
->client_to_server_buffer
, &c
->server_fd
,
183 &c
->client_to_server_buffer_full
, &c
->client_to_server_buffer_size
,
184 &c
->client_event_source
, &c
->server_event_source
);
188 /* EOF on both sides? */
189 if (c
->server_fd
== -1 && c
->client_fd
== -1)
192 /* Server closed, and all data written to client? */
193 if (c
->server_fd
== -1 && c
->server_to_client_buffer_full
<= 0)
196 /* Client closed, and all data written to server? */
197 if (c
->client_fd
== -1 && c
->client_to_server_buffer_full
<= 0)
200 r
= connection_enable_event_sources(c
);
208 return 0; /* ignore errors, continue serving */
211 static int connection_enable_event_sources(Connection
*c
) {
212 uint32_t a
= 0, b
= 0;
217 if (c
->server_to_client_buffer_full
> 0)
219 if (c
->server_to_client_buffer_full
< c
->server_to_client_buffer_size
)
222 if (c
->client_to_server_buffer_full
> 0)
224 if (c
->client_to_server_buffer_full
< c
->client_to_server_buffer_size
)
227 if (c
->server_event_source
)
228 r
= sd_event_source_set_io_events(c
->server_event_source
, a
);
229 else if (c
->server_fd
>= 0)
230 r
= sd_event_add_io(c
->context
->event
, &c
->server_event_source
, c
->server_fd
, a
, traffic_cb
, c
);
235 return log_error_errno(r
, "Failed to set up server event source: %m");
237 if (c
->client_event_source
)
238 r
= sd_event_source_set_io_events(c
->client_event_source
, b
);
239 else if (c
->client_fd
>= 0)
240 r
= sd_event_add_io(c
->context
->event
, &c
->client_event_source
, c
->client_fd
, b
, traffic_cb
, c
);
245 return log_error_errno(r
, "Failed to set up client event source: %m");
250 static int connection_complete(Connection
*c
) {
255 r
= connection_create_pipes(c
, c
->server_to_client_buffer
, &c
->server_to_client_buffer_size
);
259 r
= connection_create_pipes(c
, c
->client_to_server_buffer
, &c
->client_to_server_buffer_size
);
263 r
= connection_enable_event_sources(c
);
271 return 0; /* ignore errors, continue serving */
274 static int connect_cb(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
275 Connection
*c
= userdata
;
283 solen
= sizeof(error
);
284 r
= getsockopt(fd
, SOL_SOCKET
, SO_ERROR
, &error
, &solen
);
286 log_error_errno(errno
, "Failed to issue SO_ERROR: %m");
291 log_error_errno(error
, "Failed to connect to remote host: %m");
295 c
->client_event_source
= sd_event_source_unref(c
->client_event_source
);
297 return connection_complete(c
);
301 return 0; /* ignore errors, continue serving */
304 static int connection_start(Connection
*c
, struct sockaddr
*sa
, socklen_t salen
) {
311 c
->client_fd
= socket(sa
->sa_family
, SOCK_STREAM
|SOCK_NONBLOCK
|SOCK_CLOEXEC
, 0);
312 if (c
->client_fd
< 0) {
313 log_error_errno(errno
, "Failed to get remote socket: %m");
317 r
= connect(c
->client_fd
, sa
, salen
);
319 if (errno
== EINPROGRESS
) {
320 r
= sd_event_add_io(c
->context
->event
, &c
->client_event_source
, c
->client_fd
, EPOLLOUT
, connect_cb
, c
);
322 log_error_errno(r
, "Failed to add connection socket: %m");
326 r
= sd_event_source_set_enabled(c
->client_event_source
, SD_EVENT_ONESHOT
);
328 log_error_errno(r
, "Failed to enable oneshot event source: %m");
332 log_error_errno(errno
, "Failed to connect to remote host: %m");
336 r
= connection_complete(c
);
345 return 0; /* ignore errors, continue serving */
348 static int resolve_cb(sd_resolve_query
*q
, int ret
, const struct addrinfo
*ai
, void *userdata
) {
349 Connection
*c
= userdata
;
355 log_error("Failed to resolve host: %s", gai_strerror(ret
));
359 c
->resolve_query
= sd_resolve_query_unref(c
->resolve_query
);
361 return connection_start(c
, ai
->ai_addr
, ai
->ai_addrlen
);
365 return 0; /* ignore errors, continue serving */
368 static int resolve_remote(Connection
*c
) {
370 static const struct addrinfo hints
= {
371 .ai_family
= AF_UNSPEC
,
372 .ai_socktype
= SOCK_STREAM
,
373 .ai_flags
= AI_ADDRCONFIG
376 union sockaddr_union sa
= {};
377 const char *node
, *service
;
380 if (path_is_absolute(arg_remote_host
)) {
381 sa
.un
.sun_family
= AF_UNIX
;
382 strncpy(sa
.un
.sun_path
, arg_remote_host
, sizeof(sa
.un
.sun_path
));
383 return connection_start(c
, &sa
.sa
, SOCKADDR_UN_LEN(sa
.un
));
386 if (arg_remote_host
[0] == '@') {
387 sa
.un
.sun_family
= AF_UNIX
;
388 sa
.un
.sun_path
[0] = 0;
389 strncpy(sa
.un
.sun_path
+1, arg_remote_host
+1, sizeof(sa
.un
.sun_path
)-1);
390 return connection_start(c
, &sa
.sa
, SOCKADDR_UN_LEN(sa
.un
));
393 service
= strrchr(arg_remote_host
, ':');
395 node
= strndupa(arg_remote_host
, service
- arg_remote_host
);
398 node
= arg_remote_host
;
402 log_debug("Looking up address info for %s:%s", node
, service
);
403 r
= sd_resolve_getaddrinfo(c
->context
->resolve
, &c
->resolve_query
, node
, service
, &hints
, resolve_cb
, c
);
405 log_error_errno(r
, "Failed to resolve remote host: %m");
413 return 0; /* ignore errors, continue serving */
416 static int add_connection_socket(Context
*context
, int fd
) {
423 if (set_size(context
->connections
) > arg_connections_max
) {
424 log_warning("Hit connection limit, refusing connection.");
429 r
= set_ensure_allocated(&context
->connections
, NULL
);
435 c
= new0(Connection
, 1);
441 c
->context
= context
;
444 c
->server_to_client_buffer
[0] = c
->server_to_client_buffer
[1] = -1;
445 c
->client_to_server_buffer
[0] = c
->client_to_server_buffer
[1] = -1;
447 r
= set_put(context
->connections
, c
);
454 return resolve_remote(c
);
457 static int accept_cb(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
458 _cleanup_free_
char *peer
= NULL
;
459 Context
*context
= userdata
;
464 assert(revents
& EPOLLIN
);
467 nfd
= accept4(fd
, NULL
, NULL
, SOCK_NONBLOCK
|SOCK_CLOEXEC
);
469 if (errno
!= -EAGAIN
)
470 log_warning_errno(errno
, "Failed to accept() socket: %m");
472 getpeername_pretty(nfd
, true, &peer
);
473 log_debug("New connection from %s", strna(peer
));
475 r
= add_connection_socket(context
, nfd
);
477 log_error_errno(r
, "Failed to accept connection, ignoring: %m");
482 r
= sd_event_source_set_enabled(s
, SD_EVENT_ONESHOT
);
484 log_error_errno(r
, "Error while re-enabling listener with ONESHOT: %m");
485 sd_event_exit(context
->event
, r
);
492 static int add_listen_socket(Context
*context
, int fd
) {
493 sd_event_source
*source
;
499 r
= set_ensure_allocated(&context
->listen
, NULL
);
505 r
= sd_is_socket(fd
, 0, SOCK_STREAM
, 1);
507 return log_error_errno(r
, "Failed to determine socket type: %m");
509 log_error("Passed in socket is not a stream socket.");
513 r
= fd_nonblock(fd
, true);
515 return log_error_errno(r
, "Failed to mark file descriptor non-blocking: %m");
517 r
= sd_event_add_io(context
->event
, &source
, fd
, EPOLLIN
, accept_cb
, context
);
519 return log_error_errno(r
, "Failed to add event source: %m");
521 r
= set_put(context
->listen
, source
);
523 log_error_errno(r
, "Failed to add source to set: %m");
524 sd_event_source_unref(source
);
528 /* Set the watcher to oneshot in case other processes are also
529 * watching to accept(). */
530 r
= sd_event_source_set_enabled(source
, SD_EVENT_ONESHOT
);
532 return log_error_errno(r
, "Failed to enable oneshot mode: %m");
537 static void help(void) {
538 printf("%1$s [HOST:PORT]\n"
540 "Bidirectionally proxy local sockets to another (possibly remote) socket.\n\n"
541 " -c --connections-max= Set the maximum number of connections to be accepted\n"
542 " -h --help Show this help\n"
543 " --version Show package version\n",
544 program_invocation_short_name
);
547 static int parse_argv(int argc
, char *argv
[]) {
554 static const struct option options
[] = {
555 { "connections-max", required_argument
, NULL
, 'c' },
556 { "help", no_argument
, NULL
, 'h' },
557 { "version", no_argument
, NULL
, ARG_VERSION
},
566 while ((c
= getopt_long(argc
, argv
, "c:h", options
, NULL
)) >= 0)
575 r
= safe_atou(optarg
, &arg_connections_max
);
577 log_error("Failed to parse --connections-max= argument: %s", optarg
);
581 if (arg_connections_max
< 1) {
582 log_error("Connection limit is too low.");
595 assert_not_reached("Unhandled option");
598 if (optind
>= argc
) {
599 log_error("Not enough parameters.");
603 if (argc
!= optind
+1) {
604 log_error("Too many parameters.");
608 arg_remote_host
= argv
[optind
];
612 int main(int argc
, char *argv
[]) {
613 Context context
= {};
616 log_parse_environment();
619 r
= parse_argv(argc
, argv
);
623 r
= sd_event_default(&context
.event
);
625 log_error_errno(r
, "Failed to allocate event loop: %m");
629 r
= sd_resolve_default(&context
.resolve
);
631 log_error_errno(r
, "Failed to allocate resolver: %m");
635 r
= sd_resolve_attach_event(context
.resolve
, context
.event
, 0);
637 log_error_errno(r
, "Failed to attach resolver: %m");
641 sd_event_set_watchdog(context
.event
, true);
643 n
= sd_listen_fds(1);
645 log_error("Failed to receive sockets from parent.");
649 log_error("Didn't get any sockets passed in.");
654 for (fd
= SD_LISTEN_FDS_START
; fd
< SD_LISTEN_FDS_START
+ n
; fd
++) {
655 r
= add_listen_socket(&context
, fd
);
660 r
= sd_event_loop(context
.event
);
662 log_error_errno(r
, "Failed to run event loop: %m");
667 context_free(&context
);
669 return r
< 0 ? EXIT_FAILURE
: EXIT_SUCCESS
;