xref: /freebsd/libexec/pppoed/pppoed.c (revision a79b71281cd63ad7a6cc43a6d5673a2510b51630)
1 /*-
2  * Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include <sys/param.h>
30 #include <sys/socket.h>
31 #include <sys/un.h>
32 #include <netinet/in.h>
33 #include <arpa/inet.h>
34 #include <netdb.h>
35 #include <netgraph.h>
36 #include <net/ethernet.h>
37 #include <netinet/in_systm.h>
38 #include <netinet/ip.h>
39 #include <netgraph/ng_ether.h>
40 #include <netgraph/ng_message.h>
41 #include <netgraph/ng_pppoe.h>
42 #include <netgraph/ng_socket.h>
43 
44 #include <errno.h>
45 #include <paths.h>
46 #include <signal.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <sysexits.h>
51 #include <sys/fcntl.h>
52 #ifndef NOKLDLOAD
53 #include <sys/linker.h>
54 #include <sys/module.h>
55 #endif
56 #include <sys/uio.h>
57 #include <sys/wait.h>
58 #include <syslog.h>
59 #include <termios.h>
60 #include <unistd.h>
61 
62 
63 #define DEFAULT_EXEC_PREFIX "exec /usr/sbin/ppp -direct "
64 
65 static int
66 usage(const char *prog)
67 {
68   fprintf(stderr, "Usage: %s [-Fd] [-P pidfile] [-a name] [-e exec]"
69           " [-p provider] interface\n", prog);
70   return EX_USAGE;
71 }
72 
73 const char *pidfile;
74 
75 static void
76 Fairwell(int sig)
77 {
78   char buf[] = "Received signal XX, exiting";
79 
80   /* No stdio in a signal handler */
81   buf[16] = '0' + ((sig / 10) % 10);
82   buf[17] = '0' + (sig % 10);
83 
84   syslog(LOG_INFO, buf);
85 
86   if (pidfile)
87     remove(pidfile);
88 
89   signal(sig, SIG_DFL);
90   raise(sig);
91 }
92 
93 static int
94 ConfigureNode(const char *prog, const char *iface, const char *provider,
95               int cs, int ds, int debug, struct ngm_connect *ngc)
96 {
97   /*
98    * We're going to do this with the passed `ds' & `cs' descriptors:
99    *
100    * .---------.
101    * |  ether  |
102    * | <iface> |
103    * `---------'
104    *  (orphan)                                     ds    cs
105    *     |                                         |     |
106    *     |                                         |     |
107    * (ethernet)                                    |     |
108    * .---------.                                .-----------.
109    * |  pppoe  |                                |  socket   |
110    * | <iface> |(pppoe-<pid>)<---->(pppoe-<pid>)| <unnamed> |
111    * `---------                                 `-----------'
112    * (exec-<pid>)
113    *     ^                .-----------.      .-------------.
114    *     |                |   socket  |      | ppp -direct |
115    *     `--->(exec-<pid>)| <unnamed> |--fd--|  provider   |
116    *                      `-----------'      `-------------'
117    *
118    * where there are potentially many ppp processes running off of the
119    * same PPPoE node.
120    * The exec-<pid> hook isn't made 'till we Spawn().
121    */
122 
123   char *epath, *spath;
124   struct ngpppoe_init_data *data;
125   const struct hooklist *hlist;
126   const struct nodeinfo *ninfo;
127   const struct linkinfo *nlink;
128   struct ngm_mkpeer mkp;
129   struct ng_mesg *resp;
130   u_char rbuf[2048];
131   int f, plen;
132 
133   /*
134    * Ask for a list of hooks attached to the "ether" node.  This node should
135    * magically exist as a way of hooking stuff onto an ethernet device
136    */
137   epath = (char *)alloca(strlen(iface) + 2);
138   sprintf(epath, "%s:", iface);
139 
140   if (debug)
141     fprintf(stderr, "Sending NGM_LISTHOOKS to %s\n", epath);
142 
143   if (NgSendMsg(cs, epath, NGM_GENERIC_COOKIE, NGM_LISTHOOKS, NULL, 0) < 0) {
144     if (errno == ENOENT)
145       fprintf(stderr, "%s Cannot send a netgraph message: Invalid interface\n",
146               epath);
147     else
148       fprintf(stderr, "%s Cannot send a netgraph message: %s\n",
149               epath, strerror(errno));
150     return EX_UNAVAILABLE;
151   }
152 
153   /* Get our list back */
154   resp = (struct ng_mesg *)rbuf;
155   if (NgRecvMsg(cs, resp, sizeof rbuf, NULL) < 0) {
156     perror("Cannot get netgraph response");
157     return EX_UNAVAILABLE;
158   }
159 
160   hlist = (const struct hooklist *)resp->data;
161   ninfo = &hlist->nodeinfo;
162 
163   if (debug)
164     fprintf(stderr, "Got reply from id [%x]: Type %s with %d hooks\n",
165             ninfo->id, ninfo->type, ninfo->hooks);
166 
167   /* Make sure we've got the right type of node */
168   if (strncmp(ninfo->type, NG_ETHER_NODE_TYPE, sizeof NG_ETHER_NODE_TYPE - 1)) {
169     fprintf(stderr, "%s Unexpected node type ``%s'' (wanted ``"
170             NG_ETHER_NODE_TYPE "'')\n", epath, ninfo->type);
171     return EX_DATAERR;
172   }
173 
174   /* look for a hook already attached.  */
175   for (f = 0; f < ninfo->hooks; f++) {
176     nlink = &hlist->link[f];
177 
178     if (debug)
179       fprintf(stderr, "  Got [%x]:%s -> [%x]:%s\n", ninfo->id,
180               nlink->ourhook, nlink->nodeinfo.id, nlink->peerhook);
181 
182     if (!strcmp(nlink->ourhook, NG_ETHER_HOOK_ORPHAN) ||
183         !strcmp(nlink->ourhook, NG_ETHER_HOOK_DIVERT)) {
184       /*
185        * Something is using the data coming out of this `ether' node.
186        * If it's a PPPoE node, we use that node, otherwise we complain that
187        * someone else is using the node.
188        */
189       if (strcmp(nlink->nodeinfo.type, NG_PPPOE_NODE_TYPE)) {
190         fprintf(stderr, "%s Node type %s is currently active\n",
191                 epath, nlink->nodeinfo.type);
192         return EX_UNAVAILABLE;
193       }
194       break;
195     }
196   }
197 
198   if (f == ninfo->hooks) {
199     /*
200      * Create a new PPPoE node connected to the `ether' node using
201      * the magic `orphan' and `ethernet' hooks
202      */
203     snprintf(mkp.type, sizeof mkp.type, "%s", NG_PPPOE_NODE_TYPE);
204     snprintf(mkp.ourhook, sizeof mkp.ourhook, "%s", NG_ETHER_HOOK_ORPHAN);
205     snprintf(mkp.peerhook, sizeof mkp.peerhook, "%s", NG_PPPOE_HOOK_ETHERNET);
206 
207     if (debug)
208       fprintf(stderr, "Send MKPEER: %s%s -> [type %s]:%s\n", epath,
209               mkp.ourhook, mkp.type, mkp.peerhook);
210 
211     if (NgSendMsg(cs, epath, NGM_GENERIC_COOKIE,
212                   NGM_MKPEER, &mkp, sizeof mkp) < 0) {
213       fprintf(stderr, "%s Cannot create a peer PPPoE node: %s\n",
214               epath, strerror(errno));
215       return EX_OSERR;
216     }
217   }
218 
219   /* Connect the PPPoE node to our socket node.  */
220   snprintf(ngc->path, sizeof ngc->path, "%s%s", epath, NG_ETHER_HOOK_ORPHAN);
221   snprintf(ngc->ourhook, sizeof ngc->ourhook, "pppoe-%ld", (long)getpid());
222   memcpy(ngc->peerhook, ngc->ourhook, sizeof ngc->peerhook);
223 
224   if (NgSendMsg(cs, ".:", NGM_GENERIC_COOKIE,
225                 NGM_CONNECT, ngc, sizeof *ngc) < 0) {
226     perror("Cannot CONNECT PPPoE and socket nodes");
227     return EX_OSERR;
228   }
229 
230   plen = strlen(provider);
231 
232   data = (struct ngpppoe_init_data *)alloca(sizeof *data + plen + 1);
233   snprintf(data->hook, sizeof data->hook, "%s", ngc->peerhook);
234   strcpy(data->data, provider);
235   data->data_len = plen;
236 
237   spath = (char *)alloca(strlen(ngc->peerhook) + 3);
238   strcpy(spath, ".:");
239   strcpy(spath + 2, ngc->ourhook);
240 
241   if (debug) {
242     if (provider)
243       fprintf(stderr, "Sending PPPOE_LISTEN to %s, provider %s\n",
244               spath, provider);
245     else
246       fprintf(stderr, "Sending PPPOE_LISTEN to %s\n", spath);
247   }
248 
249   if (NgSendMsg(cs, spath, NGM_PPPOE_COOKIE, NGM_PPPOE_LISTEN,
250                 data, sizeof *data + plen) == -1) {
251     fprintf(stderr, "%s: Cannot LISTEN on netgraph node: %s\n",
252             spath, strerror(errno));
253     return EX_OSERR;
254   }
255 
256   return 0;
257 }
258 
259 static void
260 Spawn(const char *prog, const char *acname, const char *exec,
261       struct ngm_connect ngc, int cs, int ds, void *request, int sz,
262       int debug)
263 {
264   char msgbuf[sizeof(struct ng_mesg) + sizeof(struct ngpppoe_sts)];
265   struct ng_mesg *rep = (struct ng_mesg *)msgbuf;
266   struct ngpppoe_sts *sts = (struct ngpppoe_sts *)(msgbuf + sizeof *rep);
267   struct ngpppoe_init_data *data;
268   char unknown[14], *path;
269   const char *msg;
270   int ret, slen;
271 
272   switch ((ret = fork())) {
273     case -1:
274       syslog(LOG_ERR, "fork: %m");
275       break;
276 
277     case 0:
278       switch (fork()) {
279         case 0:
280           break;
281         case -1:
282           _exit(errno);
283         default:
284           _exit(0);
285       }
286       close(cs);
287       close(ds);
288 
289       /* Create a new socket node */
290       if (debug)
291         syslog(LOG_INFO, "Creating a new socket node");
292 
293       if (NgMkSockNode(NULL, &cs, &ds) == -1) {
294         syslog(LOG_ERR, "Cannot create netgraph socket node: %m");
295         _exit(EX_CANTCREAT);
296       }
297 
298       /* Connect the PPPoE node to our new socket node.  */
299       snprintf(ngc.ourhook, sizeof ngc.ourhook, "exec-%ld", (long)getpid());
300       memcpy(ngc.peerhook, ngc.ourhook, sizeof ngc.peerhook);
301 
302       if (debug)
303         syslog(LOG_INFO, "Sending CONNECT from .:%s -> %s.%s",
304                ngc.ourhook, ngc.path, ngc.peerhook);
305       if (NgSendMsg(cs, ".:", NGM_GENERIC_COOKIE,
306                     NGM_CONNECT, &ngc, sizeof ngc) < 0) {
307         syslog(LOG_ERR, "Cannot CONNECT PPPoE and socket nodes: %m");
308         _exit(EX_OSERR);
309       }
310 
311       /*
312        * If we tell the socket node not to LINGER, it will go away when
313        * the last hook is removed.
314        */
315       if (debug)
316         syslog(LOG_INFO, "Sending NGM_SOCK_CMD_NOLINGER to socket");
317       if (NgSendMsg(cs, ".:", NGM_SOCKET_COOKIE,
318                     NGM_SOCK_CMD_NOLINGER, NULL, 0) < 0) {
319         syslog(LOG_ERR, "Cannot send NGM_SOCK_CMD_NOLINGER: %m");
320         _exit(EX_OSERR);
321       }
322 
323       /* Put the PPPoE node into OFFER mode */
324       slen = strlen(acname);
325       data = (struct ngpppoe_init_data *)alloca(sizeof *data + slen + 1);
326       snprintf(data->hook, sizeof data->hook, "%s", ngc.ourhook);
327       strcpy(data->data, acname);
328       data->data_len = slen;
329 
330       path = (char *)alloca(strlen(ngc.ourhook) + 3);
331       strcpy(path, ".:");
332       strcpy(path + 2, ngc.ourhook);
333 
334       syslog(LOG_INFO, "Offering to %s as access concentrator %s",
335              path, acname);
336       if (NgSendMsg(cs, path, NGM_PPPOE_COOKIE, NGM_PPPOE_OFFER,
337                     data, sizeof *data + slen) == -1) {
338         syslog(LOG_INFO, "%s: Cannot OFFER on netgraph node: %m", path);
339         _exit(EX_OSERR);
340       }
341 
342       /* And send our request data to the waiting node */
343       if (debug)
344         syslog(LOG_INFO, "Sending original request to %s (%d bytes)", path, sz);
345       if (NgSendData(ds, ngc.ourhook, request, sz) == -1) {
346         syslog(LOG_ERR, "Cannot send original request to %s: %m", path);
347         _exit(EX_OSERR);
348       }
349 
350       /* Then wait for a success indication */
351 
352       if (debug)
353         syslog(LOG_INFO, "Waiting for a SUCCESS reply %s", path);
354 
355       do {
356         if (NgRecvMsg(cs, rep, sizeof msgbuf, NULL) < 0) {
357           syslog(LOG_ERR, "%s: Cannot receive a message: %m", path);
358           _exit(EX_OSERR);
359         }
360 
361         if (rep->header.version != NG_VERSION) {
362           syslog(LOG_ERR, "%ld: Unexpected netgraph version, expected %ld",
363                  (long)rep->header.version, (long)NG_VERSION);
364           _exit(EX_PROTOCOL);
365         }
366 
367         if (rep->header.typecookie != NGM_PPPOE_COOKIE) {
368           syslog(LOG_INFO, "%ld: Unexpected netgraph cookie, expected %ld",
369                  (long)rep->header.typecookie, (long)NGM_PPPOE_COOKIE);
370           continue;
371         }
372 
373         switch (rep->header.cmd) {
374           case NGM_PPPOE_SET_FLAG:	msg = "SET_FLAG";	break;
375           case NGM_PPPOE_CONNECT:	msg = "CONNECT";	break;
376           case NGM_PPPOE_LISTEN:	msg = "LISTEN";		break;
377           case NGM_PPPOE_OFFER:		msg = "OFFER";		break;
378           case NGM_PPPOE_SUCCESS:	msg = "SUCCESS";	break;
379           case NGM_PPPOE_FAIL:		msg = "FAIL";		break;
380           case NGM_PPPOE_CLOSE:		msg = "CLOSE";		break;
381           case NGM_PPPOE_GET_STATUS:	msg = "GET_STATUS";	break;
382           default:
383             snprintf(unknown, sizeof unknown, "<%d>", (int)rep->header.cmd);
384             msg = unknown;
385             break;
386         }
387 
388         switch (rep->header.cmd) {
389           case NGM_PPPOE_FAIL:
390           case NGM_PPPOE_CLOSE:
391             syslog(LOG_ERR, "Received NGM_PPPOE_%s (hook \"%s\")",
392                    msg, sts->hook);
393             _exit(0);
394         }
395 
396         syslog(LOG_INFO, "Received NGM_PPPOE_%s (hook \"%s\")", msg, sts->hook);
397       } while (rep->header.cmd != NGM_PPPOE_SUCCESS);
398 
399       dup2(ds, STDIN_FILENO);
400       dup2(ds, STDOUT_FILENO);
401       close(ds);
402       close(cs);
403 
404       setsid();
405       syslog(LOG_INFO, "Executing: %s", exec);
406       execlp(_PATH_BSHELL, _PATH_BSHELL, "-c", exec, NULL);
407       syslog(LOG_ERR, "execlp failed: %m");
408       _exit(EX_OSFILE);
409 
410     default:
411       wait(&ret);
412       errno = ret;
413       if (errno)
414         syslog(LOG_ERR, "Second fork failed: %m");
415       break;
416   }
417 }
418 
419 int
420 main(int argc, char **argv)
421 {
422   char hostname[MAXHOSTNAMELEN];
423   char response[1024], *exec, rhook[NG_HOOKLEN + 1];
424   const char *prog, *provider, *acname;
425   struct ngm_connect ngc;
426   int ch, cs, ds, ret, optF, optd, sz, f;
427 
428   prog = strrchr(argv[0], '/');
429   prog = prog ? prog + 1 : argv[0];
430   pidfile = NULL;
431   exec = NULL;
432   acname = NULL;
433   provider = "";
434   optF = optd = 0;
435 
436   while ((ch = getopt(argc, argv, "FP:a:de:p:")) != -1) {
437     switch (ch) {
438       case 'F':
439         optF = 1;
440         break;
441 
442       case 'P':
443         pidfile = optarg;
444         break;
445 
446       case 'a':
447         acname = optarg;
448         break;
449 
450       case 'd':
451         optd = 1;
452         break;
453 
454       case 'e':
455         exec = optarg;
456         break;
457 
458       case 'p':
459         provider = optarg;
460         break;
461 
462       default:
463         return usage(prog);
464     }
465   }
466 
467   if (optind >= argc || optind + 2 < argc)
468     return usage(prog);
469 
470   if (exec == NULL) {
471     if (provider == NULL) {
472       fprintf(stderr, "%s: Either a provider or an exec command"
473               " must be given\n", prog);
474       return usage(prog);
475     }
476     exec = (char *)alloca(sizeof DEFAULT_EXEC_PREFIX + strlen(provider));
477     if (exec == NULL) {
478       fprintf(stderr, "%s: Cannot allocate %d bytes\n", prog,
479               (int)(sizeof DEFAULT_EXEC_PREFIX) + strlen(provider));
480       return EX_OSERR;
481     }
482     strcpy(exec, DEFAULT_EXEC_PREFIX);
483     strcpy(exec + sizeof DEFAULT_EXEC_PREFIX - 1, provider);
484   }
485 
486   if (acname == NULL) {
487     char *dot;
488 
489     if (gethostname(hostname, sizeof hostname))
490       strcpy(hostname, "localhost");
491     else if ((dot = strchr(hostname, '.')))
492       *dot = '\0';
493 
494     acname = hostname;
495   }
496 
497 #ifndef NOKLDLOAD
498   if (modfind("netgraph") == -1) {
499     fputs("Can't run without options NETGRAPH in the kernel\n", stderr);
500     return EX_UNAVAILABLE;
501   }
502 
503   if (modfind("ng_socket") == -1 && kldload("ng_socket") == -1) {
504     perror("kldload: ng_socket");
505     return EX_UNAVAILABLE;
506   }
507 #endif
508 
509   /* Create a socket node */
510   if (NgMkSockNode(NULL, &cs, &ds) == -1) {
511     perror("Cannot create netgraph socket node");
512     return EX_CANTCREAT;
513   }
514 
515   /* Connect it up (and fill in `ngc') */
516   if ((ret = ConfigureNode(prog, argv[optind], provider, cs, ds,
517                            optd, &ngc)) != 0) {
518     close(cs);
519     close(ds);
520     return ret;
521   }
522 
523   if (!optF && daemon(1, 0) == -1) {
524     perror("daemon()");
525     close(cs);
526     close(ds);
527     return EX_OSERR;
528   }
529 
530 
531   if (pidfile != NULL) {
532     FILE *fp;
533 
534     if ((fp = fopen(pidfile, "w")) == NULL) {
535       perror(pidfile);
536       close(cs);
537       close(ds);
538       return EX_CANTCREAT;
539     } else {
540       fprintf(fp, "%d\n", (int)getpid());
541       fclose(fp);
542     }
543   }
544 
545   openlog(prog, LOG_PID | (optF ? LOG_PERROR : 0), LOG_DAEMON);
546 
547   signal(SIGHUP, Fairwell);
548   signal(SIGINT, Fairwell);
549   signal(SIGQUIT, Fairwell);
550   signal(SIGTERM, Fairwell);
551 
552   while (1) {
553     if (*provider)
554       syslog(LOG_INFO, "Listening as provider %s", provider);
555     else
556       syslog(LOG_INFO, "Listening");
557 
558     switch (sz = NgRecvData(ds, response, sizeof response, rhook)) {
559       case -1:
560         syslog(LOG_INFO, "NgRecvData: %m");
561         break;
562       case 0:
563         syslog(LOG_INFO, "NgRecvData: socket closed");
564         break;
565       default:
566         if (optd) {
567           char *dbuf, *ptr;
568 
569           ptr = dbuf = alloca(sz * 2 + 1);
570           for (f = 0; f < sz; f++, ptr += 2)
571             sprintf(ptr, "%02x", (u_char)response[f]);
572           *ptr = '\0';
573           syslog(LOG_INFO, "Got %d bytes of data: %s", sz, dbuf);
574         }
575     }
576     if (sz <= 0) {
577       ret = EX_UNAVAILABLE;
578       break;
579     }
580     Spawn(prog, acname, exec, ngc, cs, ds, response, sz, optd);
581   }
582 
583   return ret;
584 }
585