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
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * TrIPE is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with TrIPE; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 /*----- Header files ------------------------------------------------------*/
38 #include <sys/types.h>
42 #include <sys/socket.h>
43 #include <netinet/in.h>
44 #include <arpa/inet.h>
47 #include <mLib/alloc.h>
48 #include <mLib/bits.h>
49 #include <mLib/dstr.h>
50 #include <mLib/fdflags.h>
51 #include <mLib/mdwopt.h>
52 #include <mLib/quis.h>
53 #include <mLib/report.h>
55 #include <mLib/selpk.h>
57 /*----- Data structures ---------------------------------------------------*/
60 struct pk
*next
; /* Next packet in the chain */
61 octet
*p
, *o
; /* Buffer start and current posn */
62 size_t n
; /* Size of packet remaining */
65 typedef struct pkstream
{
66 unsigned f
; /* Flags... */
67 #define PKF_FULL 1u /* Buffer is full: stop reading */
68 sel_file r
, w
; /* Read and write selectors */
69 pk
*pks
, **pk_tail
; /* Packet queue */
70 size_t npk
, szpk
; /* Number and size of data */
71 selpk p
; /* Packet parser */
74 typedef struct connwait
{
75 sel_file a
; /* Selector */
76 struct sockaddr_in me
; /* Who I'm meant to be */
77 struct in_addr peer
; /* Who my peer is */
80 /*----- Static variables --------------------------------------------------*/
85 static size_t pk_nmax
= 128, pk_szmax
= 1024 * 1024;
87 /*----- Main code ---------------------------------------------------------*/
89 static int nonblockify(int fd
)
90 { return (fdflags(fd
, O_NONBLOCK
, O_NONBLOCK
, 0, 0)); }
92 static int cloexec(int fd
)
93 { return (fdflags(fd
, 0, 0, FD_CLOEXEC
, FD_CLOEXEC
)); }
95 static void dolisten(void);
97 static void doclose(pkstream
*p
)
101 close(p
->p
.reader
.fd
);
102 selpk_destroy(&p
->p
);
103 if (!(p
->f
& PKF_FULL
))
107 for (pk
= p
->pks
; pk
; pk
= ppk
) {
113 if (cw
.me
.sin_port
!= 0)
119 static void rdtcp(octet
*b
, size_t sz
, pkbuf
*pk
, size_t *k
, void *vp
)
129 if (pksz
+ 2 == sz
) {
130 write(fd_udp
, b
+ 2, pksz
);
131 selpk_want(&p
->p
, 2);
133 selpk_want(&p
->p
, pksz
+ 2);
138 static void wrtcp(int fd
, unsigned mode
, void *vp
)
141 struct iovec iov
[NPK
];
147 for (i
= 0, pk
= p
->pks
; i
< NPK
&& pk
; i
++, pk
= pk
->next
) {
148 iov
[i
].iov_base
= pk
->o
;
149 iov
[i
].iov_len
= pk
->n
;
152 if ((n
= writev(fd
, iov
, i
)) < 0) {
153 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
155 moan("couldn't write to TCP socket: %s", strerror(errno
));
161 for (pk
= p
->pks
; n
&& pk
; pk
= ppk
) {
176 p
->pk_tail
= &p
->pks
;
179 if ((p
->f
& PKF_FULL
) && p
->npk
< pk_nmax
&& p
->szpk
< pk_szmax
) {
185 static void rdudp(int fd
, unsigned mode
, void *vp
)
192 if ((n
= read(fd
, buf
, sizeof(buf
))) < 0) {
193 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
195 moan("couldn't read from UDP socket: %s", strerror(errno
));
198 pk
= xmalloc(sizeof(*pk
));
200 pk
->p
= xmalloc(n
+ 2);
202 memcpy(pk
->p
+ 2, buf
, n
);
206 p
->pk_tail
= &pk
->next
;
212 if (p
->npk
>= pk_nmax
|| p
->szpk
>= pk_szmax
) {
218 static void dofwd(int fd_in
, int fd_out
)
220 pkstream
*p
= xmalloc(sizeof(*p
));
221 sel_initfile(&sel
, &p
->r
, fd_udp
, SEL_READ
, rdudp
, p
);
222 sel_initfile(&sel
, &p
->w
, fd_out
, SEL_WRITE
, wrtcp
, p
);
223 selpk_init(&p
->p
, &sel
, fd_in
, rdtcp
, p
);
224 selpk_want(&p
->p
, 2);
226 p
->pk_tail
= &p
->pks
;
227 p
->npk
= p
->szpk
= 0;
232 static void doaccept(int fd_s
, unsigned mode
, void *p
)
235 struct sockaddr_in sin
;
236 socklen_t sz
= sizeof(sin
);
238 if ((fd
= accept(fd_s
, (struct sockaddr
*)&sin
, &sz
)) < 0) {
239 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
241 moan("couldn't accept incoming connection: %s", strerror(errno
));
244 if (cw
.peer
.s_addr
!= INADDR_ANY
&&
245 cw
.peer
.s_addr
!= sin
.sin_addr
.s_addr
) {
247 moan("rejecting connection from %s", inet_ntoa(sin
.sin_addr
));
250 if (nonblockify(fd
) || cloexec(fd
)) {
252 moan("couldn't accept incoming connection: %s", strerror(errno
));
260 static void dolisten(void)
265 if ((fd
= socket(PF_INET
, SOCK_STREAM
, 0)) < 0 ||
266 setsockopt(fd
, SOL_SOCKET
, SO_REUSEADDR
, &opt
, sizeof(opt
)) ||
267 bind(fd
, (struct sockaddr
*)&cw
.me
, sizeof(cw
.me
)) ||
268 listen(fd
, 1) || nonblockify(fd
) || cloexec(fd
))
269 die(1, "couldn't set up listening socket: %s", strerror(errno
));
270 sel_initfile(&sel
, &cw
.a
, fd
, SEL_READ
, doaccept
, 0);
274 static void parseaddr(const char *pp
, struct in_addr
*a
, unsigned short *pt
)
276 char *p
= xstrdup(pp
);
282 die(1, "missing port number in address `%s'", p
);
289 if ((h
= gethostbyname(p
)) == 0)
290 die(1, "unknown host `%s'", p
);
291 memcpy(a
, h
->h_addr
, sizeof(*a
));
298 if ((s
= getservbyname(q
, "tcp")) != 0)
300 else if ((n
= strtoul(q
, &qq
, 0)) == 0 || *qq
|| n
> 0xffff)
301 die(1, "bad port number `%s'", q
);
307 static void usage(FILE *fp
)
310 "Usage: $ [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\
311 ADDR:PORT ADDR:PORT\n");
314 static void version(FILE *fp
)
315 { pquis(fp
, "$, tripe version " VERSION
"\n"); }
317 static void help(FILE *fp
)
325 -h, --help Display this help text.\n\
326 -v, --version Display version number.\n\
327 -u, --usage Display pointless usage message.\n\
329 -l, --listen=PORT Listen for connections to TCP PORT.\n\
330 -p, --peer=ADDR Only accept connections from IP ADDR.\n\
331 -b, --bind=ADDR Bind to ADDR before connecting.\n\
332 -c, --connect=ADDR:PORT Connect to IP ADDR, TCP PORT.\n\
334 Forwards UDP packets over a reliable stream. By default, uses stdin and\n\
335 stdout; though it can use TCP sockets instead.\n\
339 int main(int argc
, char *argv
[])
343 struct sockaddr_in connaddr
, bindaddr
;
344 struct sockaddr_in udp_me
, udp_peer
;
350 bindaddr
.sin_family
= AF_INET
;
351 bindaddr
.sin_addr
.s_addr
= INADDR_ANY
;
352 bindaddr
.sin_port
= 0;
353 connaddr
.sin_family
= AF_INET
;
354 connaddr
.sin_addr
.s_addr
= INADDR_ANY
;
355 cw
.me
.sin_family
= AF_INET
;
356 cw
.me
.sin_addr
.s_addr
= INADDR_ANY
;
358 cw
.peer
.s_addr
= INADDR_ANY
;
361 static struct option opt
[] = {
362 { "help", 0, 0, 'h' },
363 { "version", 0, 0, 'v' },
364 { "usage", 0, 0, 'u' },
365 { "listen", OPTF_ARGREQ
, 0, 'l' },
366 { "peer", OPTF_ARGREQ
, 0, 'p' },
367 { "bind", OPTF_ARGREQ
, 0, 'b' },
368 { "connect", OPTF_ARGREQ
, 0, 'c' },
373 i
= mdwopt(argc
, argv
, "hvul:p:b:c:", opt
, 0, 0, 0);
387 parseaddr(optarg
, 0, &pt
);
391 parseaddr(optarg
, &cw
.peer
, 0);
394 parseaddr(optarg
, &bindaddr
.sin_addr
, 0);
397 parseaddr(optarg
, &connaddr
.sin_addr
, &pt
);
398 connaddr
.sin_port
= pt
;
405 if (optind
+ 2 != argc
|| (f
& f_bogus
)) {
410 udp_me
.sin_family
= udp_peer
.sin_family
= AF_INET
;
411 parseaddr(argv
[optind
], &udp_me
.sin_addr
, &pt
);
412 udp_me
.sin_port
= pt
;
413 parseaddr(argv
[optind
+ 1], &udp_peer
.sin_addr
, &pt
);
414 udp_peer
.sin_port
= pt
;
416 if ((fd_udp
= socket(PF_INET
, SOCK_DGRAM
, 0)) < 0 ||
417 bind(fd_udp
, (struct sockaddr
*)&udp_me
, sizeof(udp_me
)) ||
418 connect(fd_udp
, (struct sockaddr
*)&udp_peer
, sizeof(udp_peer
)) ||
419 setsockopt(fd_udp
, SOL_SOCKET
, SO_RCVBUF
, &len
, sizeof(len
)) ||
420 setsockopt(fd_udp
, SOL_SOCKET
, SO_SNDBUF
, &len
, sizeof(len
)) ||
421 nonblockify(fd_udp
) || cloexec(fd_udp
))
422 die(1, "couldn't set up UDP socket: %s", strerror(errno
));
424 if (cw
.me
.sin_port
!= 0)
426 else if (connaddr
.sin_addr
.s_addr
!= INADDR_ANY
) {
428 if ((fd
= socket(PF_INET
, SOCK_STREAM
, 0)) < 0 ||
429 bind(fd
, (struct sockaddr
*)&bindaddr
, sizeof(bindaddr
)) ||
430 connect(fd
, (struct sockaddr
*)&connaddr
, sizeof(connaddr
)) ||
431 nonblockify(fd
) || cloexec(fd
))
432 die(1, "couldn't connect to TCP server: %s", strerror(errno
));
435 dofwd(STDIN_FILENO
, STDOUT_FILENO
);
442 /*----- That's all, folks -------------------------------------------------*/