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 ---------------------------------------------------*/
62 struct sockaddr_in sin
;
66 struct pk
*next
; /* Next packet in the chain */
67 octet
*p
, *o
; /* Buffer start and current posn */
68 size_t n
; /* Size of packet remaining */
71 typedef struct pkstream
{
72 unsigned f
; /* Flags... */
73 #define PKF_FULL 1u /* Buffer is full: stop reading */
74 sel_file r
, w
; /* Read and write selectors */
75 pk
*pks
, **pk_tail
; /* Packet queue */
76 size_t npk
, szpk
; /* Number and size of data */
77 selpk p
; /* Packet parser */
80 typedef struct connwait
{
81 unsigned f
; /* Various flags */
82 #define cwf_port 1u /* Port is defined => listen */
83 sel_file a
; /* Selector */
84 addr me
, peer
; /* Who I'm meant to be; who peer is */
87 /*----- Static variables --------------------------------------------------*/
92 static size_t pk_nmax
= 128, pk_szmax
= 1024*1024;
94 /*----- Main code ---------------------------------------------------------*/
96 static int nonblockify(int fd
)
97 { return (fdflags(fd
, O_NONBLOCK
, O_NONBLOCK
, 0, 0)); }
99 static int cloexec(int fd
)
100 { return (fdflags(fd
, 0, 0, FD_CLOEXEC
, FD_CLOEXEC
)); }
102 static socklen_t
addrsz(const addr
*a
)
104 switch (a
->sa
.sa_family
) {
105 case AF_INET
: return sizeof(a
->sin
);
110 static const char *addrstr(const addr
*a
)
112 static char buf
[128];
113 socklen_t n
= sizeof(buf
);
115 if (getnameinfo(&a
->sa
, addrsz(a
), buf
, n
, 0, 0, NI_NUMERICHOST
))
116 return ("<addrstr failed>");
120 static int addreq(const addr
*a
, const addr
*b
)
122 if (a
->sa
.sa_family
!= b
->sa
.sa_family
) return (0);
123 switch (a
->sa
.sa_family
) {
125 return (a
->sin
.sin_addr
.s_addr
== b
->sin
.sin_addr
.s_addr
);
131 static void initaddr(addr
*a
)
133 a
->sin
.sin_family
= AF_INET
;
134 a
->sin
.sin_addr
.s_addr
= INADDR_ANY
;
138 static void dolisten(void);
140 static void doclose(pkstream
*p
)
144 close(p
->p
.reader
.fd
);
145 selpk_destroy(&p
->p
);
146 if (!(p
->f
&PKF_FULL
)) sel_rmfile(&p
->r
);
147 if (p
->npk
) sel_rmfile(&p
->w
);
148 for (pk
= p
->pks
; pk
; pk
= ppk
) {
154 if (cw
.f
&cwf_port
) dolisten();
158 static void rdtcp(octet
*b
, size_t sz
, pkbuf
*pk
, size_t *k
, void *vp
)
163 if (!sz
) { doclose(p
); return; }
165 if (pksz
+ 2 == sz
) {
166 DISCARD(write(fd_udp
, b
+ 2, pksz
));
167 selpk_want(&p
->p
, 2);
169 selpk_want(&p
->p
, pksz
+ 2);
174 static void wrtcp(int fd
, unsigned mode
, void *vp
)
177 struct iovec iov
[NPK
];
183 for (i
= 0, pk
= p
->pks
; i
< NPK
&& pk
; i
++, pk
= pk
->next
) {
184 iov
[i
].iov_base
= pk
->o
;
185 iov
[i
].iov_len
= pk
->n
;
188 if ((n
= writev(fd
, iov
, i
)) < 0) {
189 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
) return;
190 moan("couldn't write to TCP socket: %s", strerror(errno
));
196 for (pk
= p
->pks
; n
&& pk
; pk
= ppk
) {
210 if (!pk
) { p
->pk_tail
= &p
->pks
; sel_rmfile(&p
->w
); }
211 if ((p
->f
&PKF_FULL
) && p
->npk
< pk_nmax
&& p
->szpk
< pk_szmax
)
212 { p
->f
&= ~PKF_FULL
; sel_addfile(&p
->r
); }
215 static void rdudp(int fd
, unsigned mode
, void *vp
)
222 if ((n
= read(fd
, buf
, sizeof(buf
))) < 0) {
223 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
225 moan("couldn't read from UDP socket: %s", strerror(errno
));
228 pk
= xmalloc(sizeof(*pk
));
230 pk
->p
= xmalloc(n
+ 2);
232 memcpy(pk
->p
+ 2, buf
, n
);
236 p
->pk_tail
= &pk
->next
;
237 if (!p
->npk
) sel_addfile(&p
->w
);
241 if (p
->npk
>= pk_nmax
|| p
->szpk
>= pk_szmax
)
242 { sel_rmfile(&p
->r
); p
->f
|= PKF_FULL
; }
245 static void dofwd(int fd_in
, int fd_out
)
247 pkstream
*p
= xmalloc(sizeof(*p
));
248 sel_initfile(&sel
, &p
->r
, fd_udp
, SEL_READ
, rdudp
, p
);
249 sel_initfile(&sel
, &p
->w
, fd_out
, SEL_WRITE
, wrtcp
, p
);
250 selpk_init(&p
->p
, &sel
, fd_in
, rdtcp
, p
);
251 selpk_want(&p
->p
, 2);
253 p
->pk_tail
= &p
->pks
;
254 p
->npk
= p
->szpk
= 0;
259 static void doaccept(int fd_s
, unsigned mode
, void *p
)
263 socklen_t sz
= sizeof(a
);
265 if ((fd
= accept(fd_s
, &a
.sa
, &sz
)) < 0) {
266 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
) return;
267 moan("couldn't accept incoming connection: %s", strerror(errno
));
270 if (cw
.peer
.sin
.sin_addr
.s_addr
!= INADDR_ANY
&& !addreq(&a
, &cw
.peer
)) {
271 moan("rejecting connection from %s", addrstr(&a
));
274 if (nonblockify(fd
) || cloexec(fd
)) {
275 moan("couldn't accept incoming connection: %s", strerror(errno
));
283 static void dolisten(void)
288 if ((fd
= socket(cw
.me
.sa
.sa_family
, SOCK_STREAM
, 0)) < 0 ||
289 setsockopt(fd
, SOL_SOCKET
, SO_REUSEADDR
, &opt
, sizeof(opt
)) ||
290 bind(fd
, &cw
.me
.sa
, addrsz(&cw
.me
)) ||
291 listen(fd
, 1) || nonblockify(fd
) || cloexec(fd
))
292 die(1, "couldn't set up listening socket: %s", strerror(errno
));
293 sel_initfile(&sel
, &cw
.a
, fd
, SEL_READ
, doaccept
, 0);
298 static void parseaddr(const char *host
, const char *svc
, unsigned f
, addr
*a
)
300 char *alloc
= 0, *sep
;
307 alloc
= xstrdup(host
);
308 if ((sep
= strchr(alloc
, ':')) == 0)
309 die(1, "missing port number in address `%s'", host
);
310 host
= alloc
; *sep
= 0; svc
= sep
+ 1;
314 if ((h
= gethostbyname(host
)) == 0) die(1, "unknown host `%s'", host
);
315 memcpy(&a
->sin
.sin_addr
, h
->h_addr
, sizeof(a
->sin
.sin_addr
));
319 if ((n
= strtoul(svc
, &qq
, 0)) > 0 && !*qq
&& n
<= 0xffff)
320 a
->sin
.sin_port
= htons(n
);
321 else if ((s
= getservbyname(svc
, "tcp")) != 0)
322 a
->sin
.sin_port
= s
->s_port
;
324 die(1, "bad service name/number `%s'", svc
);
330 static void usage(FILE *fp
)
333 "Usage: $ [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\
334 ADDR:PORT ADDR:PORT\n");
337 static void version(FILE *fp
)
338 { pquis(fp
, "$, tripe version " VERSION
"\n"); }
340 static void help(FILE *fp
)
348 -h, --help Display this help text.\n\
349 -v, --version Display version number.\n\
350 -u, --usage Display pointless usage message.\n\
352 -l, --listen=PORT Listen for connections to TCP PORT.\n\
353 -p, --peer=ADDR Only accept connections from IP ADDR.\n\
354 -b, --bind=ADDR Bind to ADDR before connecting.\n\
355 -c, --connect=ADDR:PORT Connect to IP ADDR, TCP PORT.\n\
357 Forwards UDP packets over a reliable stream. By default, uses stdin and\n\
358 stdout; though it can use TCP sockets instead.\n\
362 int main(int argc
, char *argv
[])
365 const char *bindhost
= 0, *bindsvc
= 0, *peerhost
= 0;
367 const char *connhost
= 0;
379 static struct option opt
[] = {
380 { "help", 0, 0, 'h' },
381 { "version", 0, 0, 'v' },
382 { "usage", 0, 0, 'u' },
383 { "listen", OPTF_ARGREQ
, 0, 'l' },
384 { "peer", OPTF_ARGREQ
, 0, 'p' },
385 { "bind", OPTF_ARGREQ
, 0, 'b' },
386 { "connect", OPTF_ARGREQ
, 0, 'c' },
391 i
= mdwopt(argc
, argv
, "hvul:p:b:c:", opt
, 0, 0, 0);
395 case 'h': help(stdout
); exit(0);
396 case 'v': version(stdout
); exit(0);
397 case 'u': usage(stdout
); exit(0);
398 case 'l': bindsvc
= optarg
; break;
399 case 'p': peerhost
= optarg
; break;
400 case 'b': bindhost
= optarg
; break;
401 case 'c': connhost
= optarg
; break;
402 default: f
|= f_bogus
; break;
405 if (optind
+ 2 != argc
|| (f
&f_bogus
)) { usage(stderr
); exit(1); }
407 if (bindhost
&& !bindsvc
&& !connhost
)
408 die(1, "bind addr only makes sense when listening or connecting");
409 if (peerhost
&& !bindsvc
)
410 die(1, "peer addr only makes sense when listening");
411 if (bindsvc
&& connhost
)
412 die(1, "can't listen and connect");
414 if (bindhost
|| bindsvc
) {
416 if (!bindsvc
) parseaddr(bindhost
, 0, 0, &bindaddr
);
419 parseaddr(bindhost
, bindsvc
, 0, &cw
.me
);
425 if (peerhost
) parseaddr(peerhost
, 0, 0, &cw
.peer
);
429 parseaddr(connhost
, 0, paf_parse
, &tmpaddr
);
430 if ((fd
= socket(tmpaddr
.sa
.sa_family
, SOCK_STREAM
, IPPROTO_TCP
)) < 0 ||
432 bind(fd
, &bindaddr
.sa
, addrsz(&bindaddr
))) ||
433 connect(fd
, &tmpaddr
.sa
, addrsz(&tmpaddr
)))
434 die(1, "couldn't connect to TCP server: %s", strerror(errno
));
435 if (nonblockify(fd
) || cloexec(fd
))
436 die(1, "couldn't connect to TCP server: %s", strerror(errno
));
440 parseaddr(argv
[optind
], 0, paf_parse
, &tmpaddr
);
441 if ((fd_udp
= socket(tmpaddr
.sa
.sa_family
, SOCK_DGRAM
, IPPROTO_UDP
)) < 0 ||
442 nonblockify(fd_udp
) || cloexec(fd_udp
) ||
443 setsockopt(fd_udp
, SOL_SOCKET
, SO_RCVBUF
, &len
, sizeof(len
)) ||
444 setsockopt(fd_udp
, SOL_SOCKET
, SO_SNDBUF
, &len
, sizeof(len
)) ||
445 bind(fd_udp
, &tmpaddr
.sa
, addrsz(&tmpaddr
)))
446 die(1, "couldn't set up UDP socket: %s", strerror(errno
));
448 parseaddr(argv
[optind
+ 1], 0, paf_parse
, &tmpaddr
);
449 if (connect(fd_udp
, &tmpaddr
.sa
, addrsz(&tmpaddr
)))
450 die(1, "couldn't set up UDP socket: %s", strerror(errno
));
452 if (bindsvc
) dolisten();
453 else if (connhost
) dofwd(fd
, fd
);
454 else dofwd(STDIN_FILENO
, STDOUT_FILENO
);
457 if (sel_select(&sel
) && errno
!= EINTR
)
458 die(1, "select failed: %s", strerror(errno
));
463 /*----- That's all, folks -------------------------------------------------*/