a552ba9e952d2ce34489e9a1b7ea8f625609a978
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/dstr.h>
51 #include <mLib/fdflags.h>
52 #include <mLib/mdwopt.h>
53 #include <mLib/quis.h>
54 #include <mLib/report.h>
62 /*----- Data structures ---------------------------------------------------*/
64 typedef struct pkq_node
{
65 struct pkq_node
*next
;
71 pkq_node
*head
, **tail
;
74 enum { START
, OK
, ESC
, BAD
, SYNC1
, SYNC2
};
76 typedef struct client
{
82 typedef struct gobbler
{
86 typedef struct dribbler
{
89 void (*done
)(struct dribbler
*, int, void *);
93 typedef struct waiter
{
99 /*----- Static variables --------------------------------------------------*/
102 static dribbler
*dribble_out
;
103 static dstr slipbuf
= DSTR_INIT
;
104 static int slipstate
= SYNC1
;
105 static sel_file slip_in
, listener
;
106 static sel_state sel
;
107 static unsigned reasons
;
108 static waiter
*wait_head
, **wait_tail
= &wait_head
;
109 static unsigned char buf
[16384];
110 static const char *name
;
112 /*----- Utilities ---------------------------------------------------------*/
114 static void socketaddr(struct sockaddr_un
*sun
, size_t *sz
)
116 size_t n
= strlen(name
) + 1;
117 if (n
+ offsetof(struct sockaddr_un
, sun_path
) > sizeof(*sun
))
118 die(EXIT_FAILURE
, "name too long: `%s'", name
);
119 sun
->sun_family
= AF_UNIX
;
120 memcpy(sun
->sun_path
, name
, n
);
122 *sz
= n
+ offsetof(struct sockaddr_un
, sun_path
);
125 /*------ Packet queue -----------------------------------------------------*
127 * A packet queue contains a sequence of octet strings. Packets can be added
128 * to the end and read off the front.
131 static void initqueue(pkq
*q
) { q
->head
= 0; q
->tail
= &q
->head
; }
133 static pkq_node
*make_pkqnode(void *p
, size_t n
)
139 pn
= CREATE(pkq_node
);
141 pn
->buf
= xmalloc(n
);
142 memcpy(pn
->buf
, p
, n
);
148 static int enqueue(pkq
*q
, pkq_node
*pn
)
161 static void destroy_pkqnode(pkq_node
*pn
) { xfree(pn
->buf
); DESTROY(pn
); }
163 static int dequeue(pkq
*q
, int freep
)
165 pkq_node
*pn
= q
->head
;
177 static void destroy_pkq(pkq
*q
)
181 for (pn
= q
->head
; pn
; pn
= pnn
) {
185 q
->head
= 0; q
->tail
= &q
->head
;
188 /*----- Gobblers ----------------------------------------------------------*
190 * A gobbler just eats everything it sees on its input descriptor.
191 * Eventually, when it sees end-of-file, it closes the input descriptor and
195 static void gobbler_close(gobbler
*g
)
196 { if (g
->f
.fd
!= -1) { sel_rmfile(&g
->f
); g
->f
.fd
= -1; } }
198 static void gobbler_destroy(gobbler
*g
) { gobbler_close(g
); DESTROY(g
); }
200 static void do_gobble_in(int fd
, unsigned mode
, void *p
)
206 n
= read(fd
, buf
, sizeof(buf
));
208 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
211 moan("read (gobble): %s", strerror(errno
));
222 static gobbler
*make_gobbler(int fd
)
227 sel_initfile(&sel
, &g
->f
, fd
, SEL_READ
, do_gobble_in
, g
);
229 do_gobble_in(fd
, SEL_READ
, g
);
233 /*----- Dribbler ----------------------------------------------------------*
235 * A dribbler hands out data from a packet queue to a file descriptor. It
236 * makes no attempt to preserve the record boundaries inherent in the packet
237 * queue structure. If the dribbler reaches the end of its queue, it invokes
238 * a user-supplied `done' function and stops selecting its output descriptor
242 static void cripple_dribbler(dribbler
*d
) { close(d
->f
.fd
); d
->f
.fd
= -1; }
244 static void destroy_dribbler(dribbler
*d
)
245 { cripple_dribbler(d
); DESTROY(d
); }
247 static void dribble_done(dribbler
*d
, int err
)
253 d
->done(d
, err
, d
->p
);
256 static void do_dribble_out(int fd
, unsigned mode
, void *p
)
264 n
= write(fd
, pn
->buf
+ pn
->n
, pn
->sz
- pn
->n
);
266 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
269 dribble_done(d
, errno
);
274 if (pn
->n
== pn
->sz
&& dequeue(&d
->q
, 1)) {
282 static int enqueue_dribble(dribbler
*d
, pkq_node
*pn
)
288 if (enqueue(&d
->q
, pn
)) {
290 do_dribble_out(d
->f
.fd
, SEL_WRITE
, d
);
296 static dribbler
*make_dribbler(int fd
,
297 void (*done
)(dribbler
*, int, void *),
300 dribbler
*d
= CREATE(dribbler
);
301 sel_initfile(&sel
, &d
->f
, fd
, SEL_WRITE
, do_dribble_out
, d
);
308 /*----- Clients -----------------------------------------------------------*/
310 static void done_client_dribble(dribbler
*d
, int err
, void *p
)
313 moan("write (client): %s", strerror(err
));
319 static void dequeue_to_waiter(void)
325 while (q_in
.head
&& wait_head
) {
329 wait_tail
= &wait_head
;
330 d
= make_dribbler(w
->fd
, done_client_dribble
, w
->g
);
333 if (dequeue(&q_in
, 0))
335 enqueue_dribble(d
, pn
);
339 static void client_destroy(client
*c
)
348 static void do_client_in(int fd
, unsigned mode
, void *p
)
354 /* --- Attention --- *
356 * The queue for outbound packets is SLIP-encoded; we need to encode it
357 * here. The queue for inbound packets is raw.
361 n
= read(fd
, buf
, sizeof(buf
));
364 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
367 moan("read (client): %s", strerror(errno
));
372 if (c
->mode
== '>') {
373 DPUTC(&c
->d
, SL_END
);
374 if (enqueue_dribble(dribble_out
, make_pkqnode(c
->d
.buf
, c
->d
.len
)))
380 if (c
->mode
== '?') {
388 w
->g
= make_gobbler(fd
);
392 wait_tail
= &w
->next
;
398 moan("bad client mode `%c'", buf
[0]);
403 for (i
= i0
; i
< n
; i
++) {
406 DPUTC(&c
->d
, SL_ESC
);
407 DPUTC(&c
->d
, SL_ESCESC
);
410 DPUTC(&c
->d
, SL_ESC
);
411 DPUTC(&c
->d
, SL_ESCEND
);
414 DPUTC(&c
->d
, buf
[i
]);
421 static void do_accept(int fd
, unsigned mode
, void *hunoz
)
424 struct sockaddr_un sun
;
425 socklen_t n
= sizeof(sun
);
428 if ((nfd
= accept(fd
, (struct sockaddr
*)&sun
, &n
)) < 0) {
429 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
432 die(EXIT_FAILURE
, "accept: %s", strerror(errno
));
437 fdflags(nfd
, O_NONBLOCK
, O_NONBLOCK
, 0, 0);
438 sel_initfile(&sel
, &c
->f
, nfd
, SEL_READ
, do_client_in
, c
);
443 /*----- Main daemon -------------------------------------------------------*/
445 static void done_slip_dribble(dribbler
*d
, int err
, void *p
)
449 else if (err
!= EPIPE
)
450 die(EXIT_FAILURE
, "write (slip): %s", strerror(errno
));
455 static void do_slip_in(int fd
, unsigned mode
, void *hunoz
)
459 /* --- Attention --- *
461 * The queue for inbound packets contains raw data; we need to decode it
462 * here. The queue for outbound packets is SLIP-encoded.
464 * TrIPE sends two empty packets on start-up, in order to resynchronize the
465 * target. We don't need this and it messes us up.
469 n
= read(fd
, buf
, sizeof(buf
));
478 moan("eof found while processing packet (discarding)");
482 sel_rmfile(&slip_in
);
486 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
|| errno
== EINTR
)
488 die(EXIT_FAILURE
, "read (slip in): %s", strerror(errno
));
490 for (i
= 0; i
< n
; i
++) {
523 DPUTC(&slipbuf
, SL_END
);
526 DPUTC(&slipbuf
, SL_ESC
);
529 moan("found escaped end byte (discard packet and resync");
534 moan("unspected escape char 0x%02x", buf
[i
]);
547 if (enqueue(&q_in
, make_pkqnode(slipbuf
.buf
, slipbuf
.len
)))
554 DPUTC(&slipbuf
, buf
[i
]);
564 static void slipif(void)
568 struct sockaddr_un sun
;
571 /* --- Make the socket --- */
573 if ((fd
= socket(PF_UNIX
, SOCK_STREAM
, 0)) < 0)
574 die(EXIT_FAILURE
, "socket: %s", strerror(errno
));
575 socketaddr(&sun
, &sz
);
576 if (bind(fd
, (struct sockaddr
*)&sun
, sz
))
577 die(EXIT_FAILURE
, "bind: %s", strerror(errno
));
579 die(EXIT_FAILURE
, "listen: %s", strerror(errno
));
581 /* --- Set up listeners for things --- */
583 fdflags(fd
, O_NONBLOCK
, O_NONBLOCK
, 0, 0);
584 sel_initfile(&sel
, &listener
, fd
, SEL_READ
, do_accept
, 0);
585 sel_addfile(&listener
);
587 fdflags(STDIN_FILENO
, O_NONBLOCK
, O_NONBLOCK
, 0, 0);
588 fdflags(STDOUT_FILENO
, O_NONBLOCK
, O_NONBLOCK
, 0, 0);
589 sel_initfile(&sel
, &slip_in
, STDIN_FILENO
, SEL_READ
, do_slip_in
, 0);
590 dribble_out
= make_dribbler(STDOUT_FILENO
, done_slip_dribble
, 0);
591 sel_addfile(&slip_in
);
596 /* --- Write the interface name --- */
598 dstr_putf(&d
, "%s-%s\n", QUIS
, name
);
599 if (enqueue_dribble(dribble_out
, make_pkqnode(d
.buf
, d
.len
)))
603 /* --- Main loop --- */
606 if (sel_select(&sel
))
607 die(EXIT_FAILURE
, "select: %s", strerror(errno
));
615 /*----- Putting and getting -----------------------------------------------*/
617 static int make_sock(int mode
)
619 struct sockaddr_un sun
;
624 if ((fd
= socket(PF_UNIX
, SOCK_STREAM
, 0)) < 0)
625 die(EXIT_FAILURE
, "socket: %s", strerror(errno
));
626 socketaddr(&sun
, &sz
);
627 if (connect(fd
, (struct sockaddr
*)&sun
, sz
))
628 die(EXIT_FAILURE
, "connect: %s", strerror(errno
));
630 if (write(fd
, &ch
, 1) < 0)
631 die(EXIT_FAILURE
, "write (mode): %s", strerror(errno
));
635 static void shovel(int from
, int to
)
642 n
= read(from
, buf
, sizeof(buf
));
647 die(EXIT_FAILURE
, "read (shovel): %s", strerror(errno
));
654 n
= write(to
, p
, sz
);
659 die(EXIT_FAILURE
, "write (shovel): %s", strerror(errno
));
669 static void put(void) { shovel(STDIN_FILENO
, make_sock('>')); }
670 static void get(void) { shovel(make_sock('<'), STDOUT_FILENO
); }
672 /*----- Main code ---------------------------------------------------------*/
674 static void usage(FILE *fp
) { pquis(fp
, "Usage: $ [-pg] SOCKET\n"); }
676 static void version(void)
677 { pquis(stdout
, "$ (" PACKAGE
" version " VERSION
")\n"); }
679 static void help(void)
685 With no options, provides a SLIP interface for TrIPE.\n\
688 -p, --put Send packet on stdin to TrIPE.\n\
689 -g, --get Receive packet from TrIPE and write to stdout.");
692 int main(int argc
, char *argv
[])
699 const struct option opt
[] = {
700 { "help", 0, 0, 'h' },
701 { "version", 0, 0, 'v' },
702 { "put", 0, 0, 'p' },
703 { "get", 0, 0, 'g' },
706 i
= mdwopt(argc
, argv
, "hvpg", opt
, 0, 0, 0);
710 case 'h': help(); return (0);
711 case 'v': version(); return (0);
712 case 'p': case 'g': mode
= i
; break;
713 default: usage(stderr
); exit(EXIT_FAILURE
); break;
716 if (argc
- optind
!= 1) { usage(stderr
); exit(EXIT_FAILURE
); }
718 signal(SIGPIPE
, SIG_IGN
);
720 case 'd': slipif(); break;
721 case 'p': put(); break;
722 case 'g': get(); break;
727 /*----- That's all, folks -------------------------------------------------*/