xref: /freebsd/usr.sbin/ppp/server.c (revision cfd6422a5217410fbd66f7a7a8a64d9d85e61229)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1997 Brian Somers <brian@Awfulhak.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #include <sys/param.h>
32 
33 #include <sys/socket.h>
34 #include <netinet/in.h>
35 #include <sys/un.h>
36 
37 #include <errno.h>
38 #include <stdarg.h>
39 #include <stdio.h>
40 #include <string.h>
41 #include <sys/stat.h>
42 #include <termios.h>
43 #include <unistd.h>
44 
45 #include "log.h"
46 #include "descriptor.h"
47 #include "server.h"
48 #include "prompt.h"
49 #include "ncpaddr.h"
50 #include "probe.h"
51 
52 static int
53 server_UpdateSet(struct fdescriptor *d, fd_set *r, fd_set *w, fd_set *e, int *n)
54 {
55   struct server *s = descriptor2server(d);
56   struct prompt *p;
57   int sets;
58 
59   sets = 0;
60   if (r && s->fd >= 0) {
61     if (*n < s->fd + 1)
62       *n = s->fd + 1;
63     FD_SET(s->fd, r);
64     log_Printf(LogTIMER, "server: fdset(r) %d\n", s->fd);
65     sets++;
66   }
67 
68   for (p = log_PromptList(); p; p = p->next)
69     sets += descriptor_UpdateSet(&p->desc, r, w, e, n);
70 
71   return sets;
72 }
73 
74 static int
75 server_IsSet(struct fdescriptor *d, const fd_set *fdset)
76 {
77   struct server *s = descriptor2server(d);
78   struct prompt *p;
79 
80   if (s->fd >= 0 && FD_ISSET(s->fd, fdset))
81     return 1;
82 
83   for (p = log_PromptList(); p; p = p->next)
84     if (descriptor_IsSet(&p->desc, fdset))
85       return 1;
86 
87   return 0;
88 }
89 
90 static void
91 server_Read(struct fdescriptor *d, struct bundle *bundle, const fd_set *fdset)
92 {
93   struct server *s = descriptor2server(d);
94   struct sockaddr_storage ss;
95   struct sockaddr *sa = (struct sockaddr *)&ss;
96   struct sockaddr_in *sin = (struct sockaddr_in *)&ss;
97 #ifndef NOINET6
98   struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&ss;
99 #endif
100   int ssize = sizeof ss, wfd;
101   struct prompt *p;
102   struct ncpaddr addr;
103 
104   if (s->fd >= 0 && FD_ISSET(s->fd, fdset)) {
105     wfd = accept(s->fd, sa, &ssize);
106     if (wfd < 0)
107       log_Printf(LogERROR, "server_Read: accept(): %s\n", strerror(errno));
108     else if (sa->sa_len == 0) {
109       close(wfd);
110       wfd = -1;
111     }
112   } else
113     wfd = -1;
114 
115   if (wfd >= 0)
116     switch (sa->sa_family) {
117       case AF_LOCAL:
118         log_Printf(LogPHASE, "Connected to local client.\n");
119         break;
120 
121       case AF_INET:
122         ncpaddr_setsa(&addr, sa);
123         if (ntohs(sin->sin_port) < 1024) {
124           log_Printf(LogALERT, "Rejected client connection from %s:%u"
125                     "(invalid port number) !\n",
126                     ncpaddr_ntoa(&addr), ntohs(sin->sin_port));
127           close(wfd);
128           wfd = -1;
129           break;
130         }
131         log_Printf(LogPHASE, "Connected to client from %s:%u\n",
132                   ncpaddr_ntoa(&addr), ntohs(sin->sin_port));
133         break;
134 
135 #ifndef NOINET6
136       case AF_INET6:
137         ncpaddr_setsa(&addr, sa);
138         if (ntohs(sin6->sin6_port) < 1024) {
139           log_Printf(LogALERT, "Rejected client connection from %s:%u"
140                     "(invalid port number) !\n",
141                     ncpaddr_ntoa(&addr), ntohs(sin6->sin6_port));
142           close(wfd);
143           wfd = -1;
144           break;
145         }
146         log_Printf(LogPHASE, "Connected to client from %s:%u\n",
147                   ncpaddr_ntoa(&addr), ntohs(sin6->sin6_port));
148         break;
149 #endif
150 
151       default:
152         write(wfd, "Unrecognised access !\n", 22);
153         close(wfd);
154         wfd = -1;
155         break;
156     }
157 
158   if (wfd >= 0) {
159     if ((p = prompt_Create(s, bundle, wfd)) == NULL) {
160       write(wfd, "Connection refused.\n", 20);
161       close(wfd);
162     } else {
163       switch (sa->sa_family) {
164         case AF_LOCAL:
165           p->src.type = "local";
166           strncpy(p->src.from, s->cfg.sockname, sizeof p->src.from - 1);
167           p->src.from[sizeof p->src.from - 1] = '\0';
168           break;
169         case AF_INET:
170           p->src.type = "ip";
171           snprintf(p->src.from, sizeof p->src.from, "%s:%u",
172                    ncpaddr_ntoa(&addr), ntohs(sin->sin_port));
173           break;
174 #ifndef NOINET6
175         case AF_INET6:
176           p->src.type = "ip6";
177           snprintf(p->src.from, sizeof p->src.from, "%s:%u",
178                    ncpaddr_ntoa(&addr), ntohs(sin6->sin6_port));
179           break;
180 #endif
181       }
182       prompt_TtyCommandMode(p);
183       prompt_Required(p);
184     }
185   }
186 
187   log_PromptListChanged = 0;
188   for (p = log_PromptList(); p; p = p->next)
189     if (descriptor_IsSet(&p->desc, fdset)) {
190       descriptor_Read(&p->desc, bundle, fdset);
191       if (log_PromptListChanged)
192         break;
193     }
194 }
195 
196 static int
197 server_Write(struct fdescriptor *d __unused, struct bundle *bundle __unused,
198 	     const fd_set *fdset __unused)
199 {
200   /* We never want to write here ! */
201   log_Printf(LogALERT, "server_Write: Internal error: Bad call !\n");
202   return 0;
203 }
204 
205 struct server server = {
206   {
207     SERVER_DESCRIPTOR,
208     server_UpdateSet,
209     server_IsSet,
210     server_Read,
211     server_Write
212   },
213   -1,
214   { "", "", 0, 0 }
215 };
216 
217 enum server_stat
218 server_Reopen(struct bundle *bundle)
219 {
220   char name[sizeof server.cfg.sockname];
221   struct stat st;
222   u_short port;
223   mode_t mask;
224   enum server_stat ret;
225 
226   if (server.cfg.sockname[0] != '\0') {
227     strcpy(name, server.cfg.sockname);
228     mask = server.cfg.mask;
229     server_Close(bundle);
230     if (server.cfg.sockname[0] != '\0' && stat(server.cfg.sockname, &st) == 0)
231       if (!(st.st_mode & S_IFSOCK) || unlink(server.cfg.sockname) != 0)
232         return SERVER_FAILED;
233     ret = server_LocalOpen(bundle, name, mask);
234   } else if (server.cfg.port != 0) {
235     port = server.cfg.port;
236     server_Close(bundle);
237     ret = server_TcpOpen(bundle, port);
238   } else
239     ret = SERVER_UNSET;
240 
241   return ret;
242 }
243 
244 enum server_stat
245 server_LocalOpen(struct bundle *bundle, const char *name, mode_t mask)
246 {
247   struct sockaddr_un ifsun;
248   mode_t oldmask;
249   int s;
250 
251   oldmask = (mode_t)-1;		/* Silence compiler */
252 
253   if (server.cfg.sockname[0] != '\0' && !strcmp(server.cfg.sockname, name))
254     server_Close(bundle);
255 
256   memset(&ifsun, '\0', sizeof ifsun);
257   ifsun.sun_len = strlen(name);
258   if (ifsun.sun_len > sizeof ifsun.sun_path - 1) {
259     log_Printf(LogERROR, "Local: %s: Path too long\n", name);
260     return SERVER_INVALID;
261   }
262   ifsun.sun_family = AF_LOCAL;
263   strcpy(ifsun.sun_path, name);
264 
265   s = socket(PF_LOCAL, SOCK_STREAM, 0);
266   if (s < 0) {
267     log_Printf(LogERROR, "Local: socket: %s\n", strerror(errno));
268     goto failed;
269   }
270   setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &s, sizeof s);
271   if (mask != (mode_t)-1)
272     oldmask = umask(mask);
273   if (bind(s, (struct sockaddr *)&ifsun, sizeof ifsun) < 0) {
274     if (mask != (mode_t)-1)
275       umask(oldmask);
276     log_Printf(LogWARN, "Local: bind: %s\n", strerror(errno));
277     close(s);
278     goto failed;
279   }
280   if (mask != (mode_t)-1)
281     umask(oldmask);
282   if (listen(s, 5) != 0) {
283     log_Printf(LogERROR, "Local: Unable to listen to socket -"
284                " BUNDLE overload?\n");
285     close(s);
286     unlink(name);
287     goto failed;
288   }
289   server_Close(bundle);
290   server.fd = s;
291   server.cfg.port = 0;
292   strncpy(server.cfg.sockname, ifsun.sun_path, sizeof server.cfg.sockname - 1);
293   server.cfg.sockname[sizeof server.cfg.sockname - 1] = '\0';
294   server.cfg.mask = mask;
295   log_Printf(LogPHASE, "Listening at local socket %s.\n", name);
296 
297   return SERVER_OK;
298 
299 failed:
300   if (server.fd == -1) {
301     server.fd = -1;
302     server.cfg.port = 0;
303     strncpy(server.cfg.sockname, ifsun.sun_path,
304             sizeof server.cfg.sockname - 1);
305     server.cfg.sockname[sizeof server.cfg.sockname - 1] = '\0';
306     server.cfg.mask = mask;
307   }
308   return SERVER_FAILED;
309 }
310 
311 enum server_stat
312 server_TcpOpen(struct bundle *bundle, u_short port)
313 {
314   struct sockaddr_storage ss;
315   struct sockaddr_in *sin = (struct sockaddr_in *)&ss;
316 #ifndef NOINET6
317   struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&ss;
318 #endif
319   int s, sz;
320 
321   if (server.cfg.port == port)
322     server_Close(bundle);
323 
324   if (port == 0)
325     return SERVER_INVALID;
326 
327   memset(&ss, '\0', sizeof ss);
328 #ifndef NOINET6
329   if (probe.ipv6_available) {
330     sin6->sin6_family = AF_INET6;
331     sin6->sin6_port = htons(port);
332     sin6->sin6_len = (u_int8_t)sizeof ss;
333     sz = sizeof *sin6;
334     s = socket(PF_INET6, SOCK_STREAM, 0);
335   } else
336 #endif
337   {
338     sin->sin_family = AF_INET;
339     sin->sin_port = htons(port);
340     sin->sin_len = (u_int8_t)sizeof ss;
341     sin->sin_addr.s_addr = INADDR_ANY;
342     sz = sizeof *sin;
343     s = socket(PF_INET, SOCK_STREAM, 0);
344   }
345 
346   if (s < 0) {
347     log_Printf(LogERROR, "Tcp: socket: %s\n", strerror(errno));
348     goto failed;
349   }
350 
351 #ifndef NOINET6
352   if (probe.ipv6_available) {
353     int off = 0;
354     setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&off, sizeof(off));
355   }
356 #endif
357 
358   setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &s, sizeof s);
359   if (bind(s, (struct sockaddr *)&ss, sz) < 0) {
360     log_Printf(LogWARN, "Tcp: bind: %s\n", strerror(errno));
361     close(s);
362     goto failed;
363   }
364   if (listen(s, 5) != 0) {
365     log_Printf(LogERROR, "Tcp: Unable to listen to socket: %s\n",
366                strerror(errno));
367     close(s);
368     goto failed;
369   }
370   server_Close(bundle);
371   server.fd = s;
372   server.cfg.port = port;
373   *server.cfg.sockname = '\0';
374   server.cfg.mask = 0;
375   log_Printf(LogPHASE, "Listening at port %d.\n", port);
376   return SERVER_OK;
377 
378 failed:
379   if (server.fd == -1) {
380     server.fd = -1;
381     server.cfg.port = port;
382     *server.cfg.sockname = '\0';
383     server.cfg.mask = 0;
384   }
385   return SERVER_FAILED;
386 }
387 
388 int
389 server_Close(struct bundle *bundle __unused)
390 {
391   if (server.fd >= 0) {
392     if (*server.cfg.sockname != '\0') {
393       struct sockaddr_un un;
394       int sz = sizeof un;
395 
396       if (getsockname(server.fd, (struct sockaddr *)&un, &sz) == 0 &&
397           un.sun_family == AF_LOCAL && sz == sizeof un)
398         unlink(un.sun_path);
399     }
400     close(server.fd);
401     server.fd = -1;
402     /* Drop associated prompts */
403     log_DestroyPrompts(&server);
404 
405     return 1;
406   }
407 
408   return 0;
409 }
410 
411 int
412 server_Clear(struct bundle *bundle)
413 {
414   int ret;
415 
416   ret = server_Close(bundle);
417 
418   server.fd = -1;
419   server.cfg.port = 0;
420   *server.cfg.sockname = '\0';
421   server.cfg.mask = 0;
422 
423   return ret;
424 }
425