3 * Forwarding UDP packets over a stream
5 * (c) 2003 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Trivial IP Encryption (TrIPE).
12 * TrIPE is free software: you can redistribute it and/or modify it under
13 * the terms of the GNU General Public License as published by the Free
14 * Software Foundation; either version 3 of the License, or (at your
15 * option) any later version.
17 * TrIPE is distributed in the hope that it will be useful, but WITHOUT
18 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
22 * You should have received a copy of the GNU General Public License
23 * along with TrIPE. If not, see <https://www.gnu.org/licenses/>.
26 /*----- Header files ------------------------------------------------------*/
37 #include <sys/types.h>
41 #include <sys/socket.h>
42 #include <netinet/in.h>
43 #include <arpa/inet.h>
46 #include <mLib/alloc.h>
47 #include <mLib/bits.h>
48 #include <mLib/dstr.h>
49 #include <mLib/fdflags.h>
50 #include <mLib/mdwopt.h>
51 #include <mLib/quis.h>
52 #include <mLib/report.h>
54 #include <mLib/selpk.h>
58 /*----- Data structures ---------------------------------------------------*/
61 struct pk
*next
; /* Next packet in the chain */
62 octet
*p
, *o
; /* Buffer start and current posn */
63 size_t n
; /* Size of packet remaining */
66 typedef struct pkstream
{
67 unsigned f
; /* Flags... */
68 #define PKF_FULL 1u /* Buffer is full: stop reading */
69 sel_file r
, w
; /* Read and write selectors */
70 pk
*pks
, **pk_tail
; /* Packet queue */
71 size_t npk
, szpk
; /* Number and size of data */
72 selpk p
; /* Packet parser */
75 typedef struct connwait
{
76 sel_file a
; /* Selector */
77 struct sockaddr_in me
; /* Who I'm meant to be */
78 struct in_addr peer
; /* Who my peer is */
81 /*----- Static variables --------------------------------------------------*/
86 static size_t pk_nmax
= 128, pk_szmax
= 1024 * 1024;
88 /*----- Main code ---------------------------------------------------------*/
90 static int nonblockify(int fd
)
91 { return (fdflags(fd
, O_NONBLOCK
, O_NONBLOCK
, 0, 0)); }
93 static int cloexec(int fd
)
94 { return (fdflags(fd
, 0, 0, FD_CLOEXEC
, FD_CLOEXEC
)); }
96 static void dolisten(void);
98 static void doclose(pkstream
*p
)
102 close(p
->p
.reader
.fd
);
103 selpk_destroy(&p
->p
);
104 if (!(p
->f
& PKF_FULL
))
108 for (pk
= p
->pks
; pk
; pk
= ppk
) {
114 if (cw
.me
.sin_port
!= 0)
120 static void rdtcp(octet
*b
, size_t sz
, pkbuf
*pk
, size_t *k
, void *vp
)
130 if (pksz
+ 2 == sz
) {
131 DISCARD(write(fd_udp
, b
+ 2, pksz
));
132 selpk_want(&p
->p
, 2);
134 selpk_want(&p
->p
, pksz
+ 2);
139 static void wrtcp(int fd
, unsigned mode
, void *vp
)
142 struct iovec iov
[NPK
];
148 for (i
= 0, pk
= p
->pks
; i
< NPK
&& pk
; i
++, pk
= pk
->next
) {
149 iov
[i
].iov_base
= pk
->o
;
150 iov
[i
].iov_len
= pk
->n
;
153 if ((n
= writev(fd
, iov
, i
)) < 0) {
154 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
156 moan("couldn't write to TCP socket: %s", strerror(errno
));
162 for (pk
= p
->pks
; n
&& pk
; pk
= ppk
) {
177 p
->pk_tail
= &p
->pks
;
180 if ((p
->f
& PKF_FULL
) && p
->npk
< pk_nmax
&& p
->szpk
< pk_szmax
) {
186 static void rdudp(int fd
, unsigned mode
, void *vp
)
193 if ((n
= read(fd
, buf
, sizeof(buf
))) < 0) {
194 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
196 moan("couldn't read from UDP socket: %s", strerror(errno
));
199 pk
= xmalloc(sizeof(*pk
));
201 pk
->p
= xmalloc(n
+ 2);
203 memcpy(pk
->p
+ 2, buf
, n
);
207 p
->pk_tail
= &pk
->next
;
213 if (p
->npk
>= pk_nmax
|| p
->szpk
>= pk_szmax
) {
219 static void dofwd(int fd_in
, int fd_out
)
221 pkstream
*p
= xmalloc(sizeof(*p
));
222 sel_initfile(&sel
, &p
->r
, fd_udp
, SEL_READ
, rdudp
, p
);
223 sel_initfile(&sel
, &p
->w
, fd_out
, SEL_WRITE
, wrtcp
, p
);
224 selpk_init(&p
->p
, &sel
, fd_in
, rdtcp
, p
);
225 selpk_want(&p
->p
, 2);
227 p
->pk_tail
= &p
->pks
;
228 p
->npk
= p
->szpk
= 0;
233 static void doaccept(int fd_s
, unsigned mode
, void *p
)
236 struct sockaddr_in sin
;
237 socklen_t sz
= sizeof(sin
);
239 if ((fd
= accept(fd_s
, (struct sockaddr
*)&sin
, &sz
)) < 0) {
240 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
242 moan("couldn't accept incoming connection: %s", strerror(errno
));
245 if (cw
.peer
.s_addr
!= INADDR_ANY
&&
246 cw
.peer
.s_addr
!= sin
.sin_addr
.s_addr
) {
248 moan("rejecting connection from %s", inet_ntoa(sin
.sin_addr
));
251 if (nonblockify(fd
) || cloexec(fd
)) {
253 moan("couldn't accept incoming connection: %s", strerror(errno
));
261 static void dolisten(void)
266 if ((fd
= socket(PF_INET
, SOCK_STREAM
, 0)) < 0 ||
267 setsockopt(fd
, SOL_SOCKET
, SO_REUSEADDR
, &opt
, sizeof(opt
)) ||
268 bind(fd
, (struct sockaddr
*)&cw
.me
, sizeof(cw
.me
)) ||
269 listen(fd
, 1) || nonblockify(fd
) || cloexec(fd
))
270 die(1, "couldn't set up listening socket: %s", strerror(errno
));
271 sel_initfile(&sel
, &cw
.a
, fd
, SEL_READ
, doaccept
, 0);
275 static void parseaddr(const char *pp
, struct in_addr
*a
, unsigned short *pt
)
277 char *p
= xstrdup(pp
);
283 die(1, "missing port number in address `%s'", p
);
290 if ((h
= gethostbyname(p
)) == 0)
291 die(1, "unknown host `%s'", p
);
292 memcpy(a
, h
->h_addr
, sizeof(*a
));
299 if ((s
= getservbyname(q
, "tcp")) != 0)
301 else if ((n
= strtoul(q
, &qq
, 0)) == 0 || *qq
|| n
> 0xffff)
302 die(1, "bad port number `%s'", q
);
308 static void usage(FILE *fp
)
311 "Usage: $ [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\
312 ADDR:PORT ADDR:PORT\n");
315 static void version(FILE *fp
)
316 { pquis(fp
, "$, tripe version " VERSION
"\n"); }
318 static void help(FILE *fp
)
326 -h, --help Display this help text.\n\
327 -v, --version Display version number.\n\
328 -u, --usage Display pointless usage message.\n\
330 -l, --listen=PORT Listen for connections to TCP PORT.\n\
331 -p, --peer=ADDR Only accept connections from IP ADDR.\n\
332 -b, --bind=ADDR Bind to ADDR before connecting.\n\
333 -c, --connect=ADDR:PORT Connect to IP ADDR, TCP PORT.\n\
335 Forwards UDP packets over a reliable stream. By default, uses stdin and\n\
336 stdout; though it can use TCP sockets instead.\n\
340 int main(int argc
, char *argv
[])
344 struct sockaddr_in connaddr
, bindaddr
;
345 struct sockaddr_in udp_me
, udp_peer
;
351 bindaddr
.sin_family
= AF_INET
;
352 bindaddr
.sin_addr
.s_addr
= INADDR_ANY
;
353 bindaddr
.sin_port
= 0;
354 connaddr
.sin_family
= AF_INET
;
355 connaddr
.sin_addr
.s_addr
= INADDR_ANY
;
356 cw
.me
.sin_family
= AF_INET
;
357 cw
.me
.sin_addr
.s_addr
= INADDR_ANY
;
359 cw
.peer
.s_addr
= INADDR_ANY
;
362 static struct option opt
[] = {
363 { "help", 0, 0, 'h' },
364 { "version", 0, 0, 'v' },
365 { "usage", 0, 0, 'u' },
366 { "listen", OPTF_ARGREQ
, 0, 'l' },
367 { "peer", OPTF_ARGREQ
, 0, 'p' },
368 { "bind", OPTF_ARGREQ
, 0, 'b' },
369 { "connect", OPTF_ARGREQ
, 0, 'c' },
374 i
= mdwopt(argc
, argv
, "hvul:p:b:c:", opt
, 0, 0, 0);
388 parseaddr(optarg
, 0, &pt
);
392 parseaddr(optarg
, &cw
.peer
, 0);
395 parseaddr(optarg
, &bindaddr
.sin_addr
, 0);
396 cw
.me
.sin_addr
= bindaddr
.sin_addr
;
399 parseaddr(optarg
, &connaddr
.sin_addr
, &pt
);
400 connaddr
.sin_port
= pt
;
407 if (optind
+ 2 != argc
|| (f
& f_bogus
)) {
412 udp_me
.sin_family
= udp_peer
.sin_family
= AF_INET
;
413 parseaddr(argv
[optind
], &udp_me
.sin_addr
, &pt
);
414 udp_me
.sin_port
= pt
;
415 parseaddr(argv
[optind
+ 1], &udp_peer
.sin_addr
, &pt
);
416 udp_peer
.sin_port
= pt
;
418 if ((fd_udp
= socket(PF_INET
, SOCK_DGRAM
, 0)) < 0 ||
419 bind(fd_udp
, (struct sockaddr
*)&udp_me
, sizeof(udp_me
)) ||
420 connect(fd_udp
, (struct sockaddr
*)&udp_peer
, sizeof(udp_peer
)) ||
421 setsockopt(fd_udp
, SOL_SOCKET
, SO_RCVBUF
, &len
, sizeof(len
)) ||
422 setsockopt(fd_udp
, SOL_SOCKET
, SO_SNDBUF
, &len
, sizeof(len
)) ||
423 nonblockify(fd_udp
) || cloexec(fd_udp
))
424 die(1, "couldn't set up UDP socket: %s", strerror(errno
));
426 if (cw
.me
.sin_port
!= 0)
428 else if (connaddr
.sin_addr
.s_addr
!= INADDR_ANY
) {
430 if ((fd
= socket(PF_INET
, SOCK_STREAM
, 0)) < 0 ||
431 bind(fd
, (struct sockaddr
*)&bindaddr
, sizeof(bindaddr
)) ||
432 connect(fd
, (struct sockaddr
*)&connaddr
, sizeof(connaddr
)) ||
433 nonblockify(fd
) || cloexec(fd
))
434 die(1, "couldn't connect to TCP server: %s", strerror(errno
));
437 dofwd(STDIN_FILENO
, STDOUT_FILENO
);
440 if (sel_select(&sel
) && errno
!= EINTR
)
441 die(1, "select failed: %s", strerror(errno
));
446 /*----- That's all, folks -------------------------------------------------*/