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/darray.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>
59 /*----- Data structures ---------------------------------------------------*/
63 struct sockaddr_in sin;
64 struct sockaddr_in6 sin6;
67 DA_DECL(addr_v, addr);
68 DA_DECL(str_v, const char *);
71 struct pk *next; /* Next packet in the chain */
72 octet *p, *o; /* Buffer start and current posn */
73 size_t n; /* Size of packet remaining */
76 typedef struct pkstream {
77 unsigned f; /* Flags... */
78 #define PKF_FULL 1u /* Buffer is full: stop reading */
79 sel_file r, w; /* Read and write selectors */
80 pk *pks, **pk_tail; /* Packet queue */
81 size_t npk, szpk; /* Number and size of data */
82 selpk p; /* Packet parser */
85 typedef struct connwait {
86 unsigned f; /* Various flags */
87 #define cwf_port 1u /* Port is defined => listen */
88 sel_file *sfv; /* Selectors */
89 addr_v me, peer; /* Who I'm meant to be; who peer is */
92 /*----- Static variables --------------------------------------------------*/
97 static size_t pk_nmax = 128, pk_szmax = 1024*1024;
99 /*----- Main code ---------------------------------------------------------*/
101 static int nonblockify(int fd)
102 { return (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0)); }
104 static int cloexec(int fd)
105 { return (fdflags(fd, 0, 0, FD_CLOEXEC, FD_CLOEXEC)); }
107 static socklen_t addrsz(const addr *a)
109 switch (a->sa.sa_family) {
110 case AF_INET: return sizeof(a->sin);
111 case AF_INET6: return sizeof(a->sin6);
116 static int knownafp(int af)
119 case AF_INET: case AF_INET6: return (1);
124 static int initsock(int fd, int af)
131 if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &yes, sizeof(yes)))
139 static const char *addrstr(const addr *a)
141 static char buf[128];
142 socklen_t n = sizeof(buf);
144 if (getnameinfo(&a->sa, addrsz(a), buf, n, 0, 0, NI_NUMERICHOST))
145 return ("<addrstr failed>");
149 static int addreq(const addr *a, const addr *b)
151 if (a->sa.sa_family != b->sa.sa_family) return (0);
152 switch (a->sa.sa_family) {
154 return (a->sin.sin_addr.s_addr == b->sin.sin_addr.s_addr);
156 return (!memcmp(a->sin6.sin6_addr.s6_addr,
157 b->sin6.sin6_addr.s6_addr,
159 a->sin6.sin6_scope_id == b->sin6.sin6_scope_id);
165 static void initaddr(addr *a, int af)
167 a->sa.sa_family = af;
170 a->sin.sin_addr.s_addr = INADDR_ANY;
174 memset(a->sin6.sin6_addr.s6_addr, 0, 16);
175 a->sin6.sin6_port = 0;
176 a->sin6.sin6_flowinfo = 0;
177 a->sin6.sin6_scope_id = 0;
186 static void copyaddr(addr *a, const struct sockaddr *sa, unsigned f)
188 const struct sockaddr_in *sin;
189 const struct sockaddr_in6 *sin6;
191 a->sa.sa_family = sa->sa_family;
192 switch (sa->sa_family) {
194 sin = (const struct sockaddr_in *)sa;
195 if (f&caf_addr) a->sin.sin_addr = sin->sin_addr;
196 if (f&caf_port) a->sin.sin_port = sin->sin_port;
199 sin6 = (const struct sockaddr_in6 *)sa;
201 a->sin6.sin6_addr = sin6->sin6_addr;
202 a->sin6.sin6_scope_id = sin6->sin6_scope_id;
204 if (f&caf_port) a->sin6.sin6_port = sin6->sin6_port;
212 static void dolisten(void);
214 static void doclose(pkstream *p)
218 close(p->p.reader.fd);
219 selpk_destroy(&p->p);
220 if (!(p->f&PKF_FULL)) sel_rmfile(&p->r);
221 if (p->npk) sel_rmfile(&p->w);
222 for (pk = p->pks; pk; pk = ppk) {
228 if (cw.f&cwf_port) dolisten();
232 static void rdtcp(octet *b, size_t sz, pkbuf *pk, size_t *k, void *vp)
237 if (!sz) { doclose(p); return; }
239 if (pksz + 2 == sz) {
240 DISCARD(write(fd_udp, b + 2, pksz));
241 selpk_want(&p->p, 2);
243 selpk_want(&p->p, pksz + 2);
248 static void wrtcp(int fd, unsigned mode, void *vp)
251 struct iovec iov[NPK];
257 for (i = 0, pk = p->pks; i < NPK && pk; i++, pk = pk->next) {
258 iov[i].iov_base = pk->o;
259 iov[i].iov_len = pk->n;
262 if ((n = writev(fd, iov, i)) < 0) {
263 if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) return;
264 moan("couldn't write to TCP socket: %s", strerror(errno));
270 for (pk = p->pks; n && pk; pk = ppk) {
284 if (!pk) { p->pk_tail = &p->pks; sel_rmfile(&p->w); }
285 if ((p->f&PKF_FULL) && p->npk < pk_nmax && p->szpk < pk_szmax)
286 { p->f &= ~PKF_FULL; sel_addfile(&p->r); }
289 static void rdudp(int fd, unsigned mode, void *vp)
296 if ((n = read(fd, buf, sizeof(buf))) < 0) {
297 if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
299 moan("couldn't read from UDP socket: %s", strerror(errno));
302 pk = xmalloc(sizeof(*pk));
304 pk->p = xmalloc(n + 2);
306 memcpy(pk->p + 2, buf, n);
310 p->pk_tail = &pk->next;
311 if (!p->npk) sel_addfile(&p->w);
315 if (p->npk >= pk_nmax || p->szpk >= pk_szmax)
316 { sel_rmfile(&p->r); p->f |= PKF_FULL; }
319 static void dofwd(int fd_in, int fd_out)
321 pkstream *p = xmalloc(sizeof(*p));
322 sel_initfile(&sel, &p->r, fd_udp, SEL_READ, rdudp, p);
323 sel_initfile(&sel, &p->w, fd_out, SEL_WRITE, wrtcp, p);
324 selpk_init(&p->p, &sel, fd_in, rdtcp, p);
325 selpk_want(&p->p, 2);
327 p->pk_tail = &p->pks;
328 p->npk = p->szpk = 0;
333 static void doaccept(int fd_s, unsigned mode, void *p)
337 socklen_t sz = sizeof(a);
340 if ((fd = accept(fd_s, &a.sa, &sz)) < 0) {
341 if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) return;
342 moan("couldn't accept incoming connection: %s", strerror(errno));
345 n = DA_LEN(&cw.peer);
347 for (i = 0; i < n; i++) if (addreq(&a, &DA(&cw.peer)[i])) goto match;
348 moan("rejecting connection from %s", addrstr(&a));
351 if (nonblockify(fd) || cloexec(fd)) {
352 moan("couldn't accept incoming connection: %s", strerror(errno));
357 for (i = 0; i < n; i++) { close(cw.sfv[i].fd); sel_rmfile(&cw.sfv[i]); }
360 static void dolisten1(const addr *a, sel_file *sf)
365 if ((fd = socket(a->sa.sa_family, SOCK_STREAM, IPPROTO_TCP)) < 0 ||
366 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) ||
367 initsock(fd, a->sa.sa_family) ||
368 bind(fd, &a->sa, addrsz(a)) ||
369 listen(fd, 1) || nonblockify(fd) || cloexec(fd))
370 die(1, "couldn't set up listening socket: %s", strerror(errno));
371 sel_initfile(&sel, sf, fd, SEL_READ, doaccept, 0);
375 static void dolisten(void)
380 for (i = 0; i < n; i++)
381 dolisten1(&DA(&cw.me)[i], &cw.sfv[i]);
384 static void pushaddrs(addr_v *av, const struct addrinfo *ailist)
386 const struct addrinfo *ai;
389 for (ai = ailist, n = 0; ai; ai = ai->ai_next)
390 if (knownafp(ai->ai_family)) n++;
392 for (i = DA_LEN(av), ai = ailist; ai; ai = ai->ai_next) {
393 if (!knownafp(ai->ai_family)) continue;
394 initaddr(&DA(av)[i], ai->ai_family);
395 copyaddr(&DA(av)[i++], ai->ai_addr, caf_addr | caf_port);
401 static void parseaddr(const struct addrinfo *aihint,
402 const char *host, const char *svc, unsigned f,
403 struct addrinfo **ai_out)
405 char *alloc = 0, *sep;
409 alloc = xstrdup(host);
410 if (alloc[0] != '[') {
411 if ((sep = strchr(alloc, ':')) == 0)
412 die(1, "missing port number in address `%s'", host);
413 host = alloc; *sep = 0; svc = sep + 1;
415 if ((sep = strchr(alloc, ']')) == 0 || sep[1] != ':')
416 die(1, "bad syntax in address `%s:'", host);
417 host = alloc + 1; *sep = 0; svc = sep + 2;
421 err = getaddrinfo(host, svc, aihint, ai_out);
424 die(1, "failed to resolve hostname `%s', service `%s': %s",
425 host, svc, gai_strerror(err));
427 die(1, "failed to resolve hostname `%s': %s", host, gai_strerror(err));
429 die(1, "failed to resolve service `%s': %s", svc, gai_strerror(err));
435 static void usage(FILE *fp)
438 "Usage: $ [-46] [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\
439 ADDR:PORT ADDR:PORT\n");
442 static void version(FILE *fp)
443 { pquis(fp, "$, tripe version " VERSION "\n"); }
445 static void help(FILE *fp)
453 -h, --help Display this help text.\n\
454 -v, --version Display version number.\n\
455 -u, --usage Display pointless usage message.\n\
457 -4, --ipv4 Restrict to IPv4 only.\n\
458 -6, --ipv6 Restrict to IPv6 only.\n\
459 -l, --listen=PORT Listen for connections to TCP PORT.\n\
460 -p, --peer=ADDR Only accept connections from IP ADDR.\n\
461 -b, --bind=ADDR Bind to ADDR before connecting.\n\
462 -c, --connect=ADDR:PORT Connect to IP ADDR, TCP PORT.\n\
464 Forwards UDP packets over a reliable stream. By default, uses stdin and\n\
465 stdout; though it can use TCP sockets instead.\n\
469 int main(int argc, char *argv[])
472 str_v bindhosts = DA_INIT, peerhosts = DA_INIT;
473 const char *bindsvc = 0;
475 const char *connhost = 0;
476 struct addrinfo aihint = { 0 }, *ai, *ailist;
489 static struct option opt[] = {
490 { "help", 0, 0, 'h' },
491 { "version", 0, 0, 'v' },
492 { "usage", 0, 0, 'u' },
493 { "ipv4", 0, 0, '4' },
494 { "ipv6", 0, 0, '6' },
495 { "listen", OPTF_ARGREQ, 0, 'l' },
496 { "peer", OPTF_ARGREQ, 0, 'p' },
497 { "bind", OPTF_ARGREQ, 0, 'b' },
498 { "connect", OPTF_ARGREQ, 0, 'c' },
503 i = mdwopt(argc, argv, "hvu46l:p:b:c:", opt, 0, 0, 0);
507 case 'h': help(stdout); exit(0);
508 case 'v': version(stdout); exit(0);
509 case 'u': usage(stdout); exit(0);
510 case '4': af = AF_INET; break;
511 case '6': af = AF_INET6; break;
512 case 'l': bindsvc = optarg; break;
513 case 'p': DA_PUSH(&peerhosts, optarg); break;
514 case 'b': DA_PUSH(&bindhosts, optarg); break;
515 case 'c': connhost = optarg; break;
516 default: f |= f_bogus; break;
519 if (optind + 2 != argc || (f&f_bogus)) { usage(stderr); exit(1); }
521 if (DA_LEN(&bindhosts) && !bindsvc && !connhost)
522 die(1, "bind addr only makes sense when listening or connecting");
523 if (DA_LEN(&peerhosts) && !bindsvc)
524 die(1, "peer addr only makes sense when listening");
525 if (bindsvc && connhost)
526 die(1, "can't listen and connect");
528 aihint.ai_family = af;
529 DA_CREATE(&cw.me); DA_CREATE(&cw.peer);
531 n = DA_LEN(&bindhosts);
533 aihint.ai_socktype = SOCK_STREAM;
534 aihint.ai_protocol = IPPROTO_TCP;
535 aihint.ai_flags = AI_ADDRCONFIG | AI_PASSIVE;
537 parseaddr(&aihint, 0, bindsvc, 0, &ailist);
538 pushaddrs(&cw.me, ailist);
539 freeaddrinfo(ailist);
540 } else if (!bindsvc) {
541 if (n != 1) die(1, "can only bind to one address as client");
542 parseaddr(&aihint, DA(&bindhosts)[0], 0, 0, &ailist);
543 for (ai = ailist; ai && !knownafp(ai->ai_family); ai = ai->ai_next);
545 die(1, "no usable addresses returned for `%s'", DA(&bindhosts)[0]);
546 initaddr(&bindaddr, ai->ai_family);
547 copyaddr(&bindaddr, ai->ai_addr, caf_addr);
548 aihint.ai_family = ai->ai_family;
549 freeaddrinfo(ailist);
550 } else for (i = 0; i < n; i++) {
551 parseaddr(&aihint, DA(&bindhosts)[i], bindsvc, 0, &ailist);
552 pushaddrs(&cw.me, ailist);
553 freeaddrinfo(ailist);
558 cw.sfv = xmalloc(n*sizeof(*cw.sfv));
562 n = DA_LEN(&peerhosts);
564 aihint.ai_socktype = SOCK_STREAM;
565 aihint.ai_protocol = IPPROTO_TCP;
566 aihint.ai_flags = AI_ADDRCONFIG;
567 for (i = 0; i < n; i++) {
568 parseaddr(&aihint, DA(&peerhosts)[i], 0, 0, &ailist);
569 pushaddrs(&cw.peer, ailist);
570 freeaddrinfo(ailist);
572 if (!DA_LEN(&cw.peer)) die(1, "no usable peer addresses");
576 aihint.ai_socktype = SOCK_STREAM;
577 aihint.ai_protocol = IPPROTO_TCP;
578 aihint.ai_flags = AI_ADDRCONFIG;
579 parseaddr(&aihint, connhost, 0, paf_parse, &ailist);
581 for (ai = ailist; ai; ai = ai->ai_next) {
582 if ((fd = socket(ai->ai_family, SOCK_STREAM, IPPROTO_TCP)) >= 0 &&
583 !initsock(fd, ai->ai_family) &&
584 (!DA_LEN(&bindhosts) ||
585 !bind(fd, &bindaddr.sa, addrsz(&bindaddr))) &&
586 !connect(fd, ai->ai_addr, ai->ai_addrlen))
588 if (fd >= 0) close(fd);
590 die(1, "couldn't connect to TCP server: %s", strerror(errno));
592 if (nonblockify(fd) || cloexec(fd))
593 die(1, "couldn't connect to TCP server: %s", strerror(errno));
596 aihint.ai_family = af;
597 aihint.ai_socktype = SOCK_DGRAM;
598 aihint.ai_protocol = IPPROTO_UDP;
599 aihint.ai_flags = AI_ADDRCONFIG | AI_PASSIVE;
600 parseaddr(&aihint, argv[optind], 0, paf_parse, &ailist);
601 for (ai = ailist; ai && !knownafp(ai->ai_family); ai = ai->ai_next);
602 if (!ai) die(1, "no usable addresses returned for `%s'", argv[optind]);
603 if ((fd_udp = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP)) < 0 ||
604 initsock(fd_udp, ai->ai_family) ||
605 nonblockify(fd_udp) || cloexec(fd_udp) ||
606 setsockopt(fd_udp, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
607 setsockopt(fd_udp, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)) ||
608 bind(fd_udp, ai->ai_addr, ai->ai_addrlen))
609 die(1, "couldn't set up UDP socket: %s", strerror(errno));
610 freeaddrinfo(ailist);
611 aihint.ai_family = ai->ai_family;
612 aihint.ai_flags = AI_ADDRCONFIG;
613 parseaddr(&aihint, argv[optind + 1], 0, paf_parse, &ailist);
614 for (ai = ailist; ai; ai = ai->ai_next)
615 if (!connect(fd_udp, ai->ai_addr, ai->ai_addrlen)) goto conn_udp;
616 die(1, "couldn't set up UDP socket: %s", strerror(errno));
619 if (bindsvc) dolisten();
620 else if (connhost) dofwd(fd, fd);
621 else dofwd(STDIN_FILENO, STDOUT_FILENO);
624 if (sel_select(&sel) && errno != EINTR)
625 die(1, "select failed: %s", strerror(errno));
630 /*----- That's all, folks -------------------------------------------------*/