3 * A simple SLIP implementation drivable from the command-line
5 * (c) 2008 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 ------------------------------------------------------*/
39 #include <sys/types.h>
43 #include <sys/socket.h>
45 #include <netinet/in.h>
46 #include <arpa/inet.h>
49 #include <mLib/alloc.h>
50 #include <mLib/bits.h>
51 #include <mLib/conn.h>
52 #include <mLib/dstr.h>
53 #include <mLib/fdflags.h>
54 #include <mLib/mdwopt.h>
55 #include <mLib/quis.h>
56 #include <mLib/report.h>
65 /*----- Data structures ---------------------------------------------------*/
67 typedef struct pkq_node {
68 struct pkq_node *next;
74 pkq_node *head, **tail;
77 enum { START, OK, ESC, BAD, SYNC1, SYNC2 };
79 typedef struct client {
85 typedef struct gobbler {
87 void (*done)(struct gobbler *, int, void *);
91 typedef struct dribbler {
94 void (*done)(struct dribbler *, int, void *);
98 typedef struct waiter {
104 /*----- Static variables --------------------------------------------------*/
107 static dribbler *dribble_out;
108 static dstr slipbuf = DSTR_INIT;
109 static int slipstate = SYNC1;
110 static sel_file slip_in, listener;
111 static sel_state sel;
112 static unsigned reasons;
113 static waiter *wait_head, **wait_tail = &wait_head;
114 static unsigned char buf[16384];
115 static const char *name;
117 /*----- Utilities ---------------------------------------------------------*/
119 static void socketaddr(struct sockaddr_un *sun, size_t *sz)
121 size_t n = strlen(name) + 1;
122 if (n + offsetof(struct sockaddr_un, sun_path) > sizeof(*sun))
123 die(EXIT_FAILURE, "name too long: `%s'", name);
124 sun->sun_family = AF_UNIX;
125 memcpy(sun->sun_path, name, n);
127 *sz = n + offsetof(struct sockaddr_un, sun_path);
130 /*------ Packet queue -----------------------------------------------------*
132 * A packet queue contains a sequence of octet strings. Packets can be added
133 * to the end and read off the front.
136 static void initqueue(pkq *q) { q->head = 0; q->tail = &q->head; }
138 static pkq_node *make_pkqnode(void *p, size_t n)
143 pn = CREATE(pkq_node);
145 pn->buf = xmalloc(n);
146 if (p) memcpy(pn->buf, p, n);
152 static int enqueue(pkq *q, pkq_node *pn)
164 static void destroy_pkqnode(pkq_node *pn) { xfree(pn->buf); DESTROY(pn); }
166 static int dequeue(pkq *q, int freep)
168 pkq_node *pn = q->head;
180 static void destroy_pkq(pkq *q)
184 for (pn = q->head; pn; pn = pnn) {
188 q->head = 0; q->tail = &q->head;
191 /*----- Gobblers ----------------------------------------------------------*
193 * A gobbler just eats everything it sees on its input descriptor.
194 * Eventually, when it sees end-of-file, it closes the input descriptor,
195 * calls a user-supplied calback function, and quits.
198 static void gobbler_close(gobbler *g)
199 { if (g->f.fd != -1) { sel_rmfile(&g->f); close(g->f.fd); g->f.fd = -1; } }
201 static void gobbler_destroy(gobbler *g) { gobbler_close(g); DESTROY(g); }
203 static void do_gobble_in(int fd, unsigned mode, void *p)
209 n = read(fd, buf, sizeof(buf));
211 if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
214 moan("read (gobble): %s", strerror(errno));
215 if (g->done) g->done(g, errno, g->p);
220 if (g->done) g->done(g, 0, g->p);
227 static gobbler *make_gobbler(int fd,
228 void (*done)(gobbler *, int, void *),
236 sel_initfile(&sel, &g->f, fd, SEL_READ, do_gobble_in, g);
238 do_gobble_in(fd, SEL_READ, g);
242 /*----- Dribbler ----------------------------------------------------------*
244 * A dribbler hands out data from a packet queue to a file descriptor. It
245 * makes no attempt to preserve the record boundaries inherent in the packet
246 * queue structure. If the dribbler reaches the end of its queue, it invokes
247 * a user-supplied `done' function and stops selecting its output descriptor
251 static void cripple_dribbler(dribbler *d) { close(d->f.fd); d->f.fd = -1; }
253 static void destroy_dribbler(dribbler *d)
254 { cripple_dribbler(d); DESTROY(d); }
256 static void dribble_done(dribbler *d, int err)
262 d->done(d, err, d->p);
265 static void do_dribble_out(int fd, unsigned mode, void *p)
273 n = write(fd, pn->buf + pn->n, pn->sz - pn->n);
275 if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
278 dribble_done(d, errno);
283 if (pn->n == pn->sz && dequeue(&d->q, 1)) {
291 static int enqueue_dribble(dribbler *d, pkq_node *pn)
297 if (enqueue(&d->q, pn)) {
299 do_dribble_out(d->f.fd, SEL_WRITE, d);
305 static dribbler *make_dribbler(int fd,
306 void (*done)(dribbler *, int, void *),
309 dribbler *d = CREATE(dribbler);
310 sel_initfile(&sel, &d->f, fd, SEL_WRITE, do_dribble_out, d);
317 /*----- Clients -----------------------------------------------------------*/
319 static void done_client_dribble(dribbler *d, int err, void *p)
322 moan("write (client): %s", strerror(err));
328 static void dequeue_to_waiter(void)
334 while (q_in.head && wait_head) {
338 wait_tail = &wait_head;
339 d = make_dribbler(w->fd, done_client_dribble, w->g);
342 if (dequeue(&q_in, 0))
344 enqueue_dribble(d, pn);
348 static void client_destroy(client *c)
357 static void do_client_in(int fd, unsigned mode, void *p)
363 /* --- Attention --- *
365 * The queue for outbound packets is SLIP-encoded; we need to encode it
366 * here. The queue for inbound packets is raw.
370 n = read(fd, buf, sizeof(buf));
373 if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
376 moan("read (client): %s", strerror(errno));
381 if (c->mode == '>') {
382 DPUTC(&c->d, SL_END);
383 if (enqueue_dribble(dribble_out, make_pkqnode(c->d.buf, c->d.len)))
389 if (c->mode == '?') {
397 w->g = make_gobbler(fd, 0, 0);
401 wait_tail = &w->next;
407 moan("bad client mode `%c'", buf[0]);
412 for (i = i0; i < n; i++) {
415 DPUTC(&c->d, SL_ESC);
416 DPUTC(&c->d, SL_ESCESC);
419 DPUTC(&c->d, SL_ESC);
420 DPUTC(&c->d, SL_ESCEND);
423 DPUTC(&c->d, buf[i]);
430 static void do_accept(int fd, unsigned mode, void *hunoz)
433 struct sockaddr_un sun;
434 socklen_t n = sizeof(sun);
437 if ((nfd = accept(fd, (struct sockaddr *)&sun, &n)) < 0) {
438 if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
441 die(EXIT_FAILURE, "accept: %s", strerror(errno));
446 fdflags(nfd, O_NONBLOCK, O_NONBLOCK, 0, 0);
447 sel_initfile(&sel, &c->f, nfd, SEL_READ, do_client_in, c);
452 /*----- Main daemon -------------------------------------------------------*/
454 static void done_slip_dribble(dribbler *d, int err, void *p)
458 else if (err != EPIPE)
459 die(EXIT_FAILURE, "write (slip): %s", strerror(errno));
464 static void do_slip_in(int fd, unsigned mode, void *hunoz)
468 /* --- Attention --- *
470 * The queue for inbound packets contains raw data; we need to decode it
471 * here. The queue for outbound packets is SLIP-encoded.
473 * TrIPE sends two empty packets on start-up, in order to resynchronize the
474 * target. We don't need this and it messes us up.
478 n = read(fd, buf, sizeof(buf));
487 moan("eof found while processing packet (discarding)");
491 sel_rmfile(&slip_in);
495 if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
497 die(EXIT_FAILURE, "read (slip in): %s", strerror(errno));
499 for (i = 0; i < n; i++) {
532 DPUTC(&slipbuf, SL_END);
536 DPUTC(&slipbuf, SL_ESC);
540 moan("found escaped end byte (discard packet and resync");
545 moan("unexpected escape char 0x%02x", buf[i]);
558 if (enqueue(&q_in, make_pkqnode(slipbuf.buf, slipbuf.len)))
565 DPUTC(&slipbuf, buf[i]);
575 static void slipif(void)
579 struct sockaddr_un sun;
582 /* --- Make the socket --- */
584 if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
585 die(EXIT_FAILURE, "socket: %s", strerror(errno));
586 socketaddr(&sun, &sz);
587 if (bind(fd, (struct sockaddr *)&sun, sz))
588 die(EXIT_FAILURE, "bind: %s", strerror(errno));
590 die(EXIT_FAILURE, "listen: %s", strerror(errno));
592 /* --- Set up listeners for things --- */
594 fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0);
595 sel_initfile(&sel, &listener, fd, SEL_READ, do_accept, 0);
596 sel_addfile(&listener);
598 fdflags(STDIN_FILENO, O_NONBLOCK, O_NONBLOCK, 0, 0);
599 fdflags(STDOUT_FILENO, O_NONBLOCK, O_NONBLOCK, 0, 0);
600 sel_initfile(&sel, &slip_in, STDIN_FILENO, SEL_READ, do_slip_in, 0);
601 dribble_out = make_dribbler(STDOUT_FILENO, done_slip_dribble, 0);
602 sel_addfile(&slip_in);
607 /* --- Write the interface name --- */
609 dstr_putf(&d, "%s-%s\n", QUIS, name);
610 if (enqueue_dribble(dribble_out, make_pkqnode(d.buf, d.len)))
614 /* --- Main loop --- */
617 if (sel_select(&sel))
618 die(EXIT_FAILURE, "select: %s", strerror(errno));
626 /*----- Putting and getting -----------------------------------------------*/
628 static int make_sock(int mode)
630 struct sockaddr_un sun;
635 if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
636 die(EXIT_FAILURE, "socket: %s", strerror(errno));
637 socketaddr(&sun, &sz);
638 if (connect(fd, (struct sockaddr *)&sun, sz))
639 die(EXIT_FAILURE, "connect: %s", strerror(errno));
641 if (write(fd, &ch, 1) < 0)
642 die(EXIT_FAILURE, "write (mode): %s", strerror(errno));
646 static void shovel(int from, int to)
653 n = read(from, buf, sizeof(buf));
658 die(EXIT_FAILURE, "read (shovel): %s", strerror(errno));
665 n = write(to, p, sz);
670 die(EXIT_FAILURE, "write (shovel): %s", strerror(errno));
680 static void put(void) { shovel(STDIN_FILENO, make_sock('>')); }
681 static void get(void) { shovel(make_sock('<'), STDOUT_FILENO); }
683 /*----- Flooding and sinking ----------------------------------------------*/
685 /* --- Connection jobs --- */
687 typedef struct conninfo {
688 struct conninfo *next;
693 static conninfo conns[MAXCONN], *freeconns;
695 static void (*connhook)(int, conninfo *);
697 static void connrecycle(conninfo *c) { c->next = freeconns; freeconns = c; }
699 static void connerr(conninfo *c)
701 if (errno == EAGAIN) connrecycle(c);
702 else die(EXIT_FAILURE, "connect: %s", strerror(errno));
705 static void connected(int fd, void *p)
706 { if (fd == -1) connerr(p); else connhook(fd, p); }
708 static void conndoconnect(conninfo *c)
711 struct sockaddr_un sun;
714 if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
715 die(EXIT_FAILURE, "socket: %s", strerror(errno));
716 socketaddr(&sun, &sz);
717 if (conn_init(&c->c, &sel, fd, (struct sockaddr *)&sun, sz, connected, c))
721 static int timerflag;
723 static void conndrip(struct timeval *tv, void *p)
729 c = freeconns; freeconns = 0;
730 while (c) { cc = c->next; conndoconnect(c); c = cc; }
734 static void connloop(void (*connected)(int, conninfo *))
741 connhook = connected;
742 for (i = 0, cc = &freeconns; i < MAXCONN; i++) {
749 if (freeconns && !timerflag) {
750 gettimeofday(&tv, 0);
751 TV_ADDL(&tv, &tv, 0, 10000);
752 sel_addtimer(&sel, &t, &tv, conndrip, 0);
755 if (sel_select(&sel))
756 die(EXIT_FAILURE, "select: %s", strerror(errno));
760 /* --- Sinking (glug glug) --- */
762 static void sink_close(gobbler *g, int err, void *p)
764 static char baton[4] = "/-\\|";
766 static int count = 0;
767 static int state = '?';
773 state = isatty(STDOUT_FILENO) ? 'y' : 'n';
781 if (pos >= sizeof(baton)) pos = 0;
789 static void sink_connected(int fd, conninfo *c)
793 if (write(fd, &dir, 1) != 1) {
794 moan("write: %s (continuing)", strerror(errno));
799 make_gobbler(fd, sink_close, c);
802 static void sink(void) { connloop(sink_connected); }
804 /* --- Flooding --- */
806 static void flood_close(dribbler *d, int err, void *p)
810 if (err) moan("write: %s (continuing)\n", strerror(errno));
815 static void flood_connected(int fd, conninfo *c)
823 #define FLOOD_PKSZ 1024
825 pn = make_pkqnode(0, 1 + FLOOD_PKSZ);
827 STORE32(pn->buf + 1, seq);
828 for (i = 4; i < FLOOD_PKSZ; i++)
829 pn->buf[i + 1] = i & 0xff;
831 d = make_dribbler(fd, flood_close, c);
832 enqueue_dribble(d, pn);
835 static void flood(void) { connloop(flood_connected); }
837 /*----- Main code ---------------------------------------------------------*/
839 static void usage(FILE *fp) { pquis(fp, "Usage: $ [-fgps] SOCKET\n"); }
841 static void version(void)
842 { pquis(stdout, "$ (" PACKAGE " version " VERSION")\n"); }
844 static void help(void)
850 With no options, provides a SLIP interface for TrIPE.\n\
853 -f, --flood Send packets to TrIPE as fast as possible.\n\
854 -g, --get Receive packet from TrIPE and write to stdout.\n\
855 -p, --put Send packet on stdin to TrIPE.\n\
856 -s, --sink Slurp packets out of TrIPE and display progress.");
859 int main(int argc, char *argv[])
866 const struct option opt[] = {
867 { "help", 0, 0, 'h' },
868 { "version", 0, 0, 'v' },
869 { "put", 0, 0, 'p' },
870 { "get", 0, 0, 'g' },
871 { "flood", 0, 0, 'f' },
872 { "sink", 0, 0, 's' },
875 i = mdwopt(argc, argv, "hvpgfs", opt, 0, 0, 0);
879 case 'h': help(); return (0);
880 case 'v': version(); return (0);
881 case 'p': case 'g': case 's': case 'f': mode = i; break;
882 default: usage(stderr); exit(EXIT_FAILURE); break;
885 if (argc - optind != 1) { usage(stderr); exit(EXIT_FAILURE); }
887 signal(SIGPIPE, SIG_IGN);
889 case 'd': slipif(); break;
890 case 'p': put(); break;
891 case 'g': get(); break;
892 case 'f': flood(); break;
893 case 's': sink(); break;
898 /*----- That's all, folks -------------------------------------------------*/