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 -------------------------------------------------*/