xref: /freebsd/usr.sbin/ppp/udp.c (revision ba3c1f5972d7b90feb6e6da47905ff2757e0fe57)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 1999 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/types.h>
32 #include <sys/socket.h>
33 #include <netinet/in.h>
34 #include <arpa/inet.h>
35 #include <netdb.h>
36 
37 #include <errno.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <sysexits.h>
42 #include <sys/stat.h>
43 #include <sys/uio.h>
44 #include <termios.h>
45 #include <unistd.h>
46 
47 #include "layer.h"
48 #include "defs.h"
49 #include "mbuf.h"
50 #include "log.h"
51 #include "timer.h"
52 #include "lqr.h"
53 #include "hdlc.h"
54 #include "throughput.h"
55 #include "fsm.h"
56 #include "lcp.h"
57 #include "ccp.h"
58 #include "link.h"
59 #include "async.h"
60 #include "descriptor.h"
61 #include "physical.h"
62 #include "main.h"
63 #include "udp.h"
64 
65 
66 #define UDP_CONNECTED		1
67 #define UDP_UNCONNECTED		2
68 #define UDP_MAYBEUNCONNECTED	3
69 
70 struct udpdevice {
71   struct device dev;		/* What struct physical knows about */
72   struct sockaddr_in sock;	/* peer address */
73   unsigned connected : 2;	/* Have we connect()d ? */
74 };
75 
76 #define device2udp(d) ((d)->type == UDP_DEVICE ? (struct udpdevice *)d : NULL)
77 
78 unsigned
79 udp_DeviceSize(void)
80 {
81   return sizeof(struct udpdevice);
82 }
83 
84 static ssize_t
85 udp_Sendto(struct physical *p, const void *v, size_t n)
86 {
87   struct udpdevice *dev = device2udp(p->handler);
88   int ret;
89 
90   switch (dev->connected) {
91     case UDP_CONNECTED:
92       ret = write(p->fd, v, n);
93       break;
94 
95     case UDP_UNCONNECTED:
96     default:
97       ret = sendto(p->fd, v, n, 0, (struct sockaddr *)&dev->sock,
98                    sizeof dev->sock);
99       break;
100   }
101   if (dev->connected == UDP_MAYBEUNCONNECTED) {
102     if (ret == -1 && errno == EISCONN) {
103       dev->connected = UDP_CONNECTED;
104       ret = write(p->fd, v, n);
105     } else
106       dev->connected = UDP_UNCONNECTED;
107   }
108 
109   return ret;
110 }
111 
112 static ssize_t
113 udp_Recvfrom(struct physical *p, void *v, size_t n)
114 {
115   struct udpdevice *dev = device2udp(p->handler);
116   int sz, ret;
117 
118   if (dev->connected == UDP_CONNECTED)
119     return read(p->fd, v, n);
120 
121   sz = sizeof dev->sock;
122   ret = recvfrom(p->fd, v, n, 0, (struct sockaddr *)&dev->sock, &sz);
123 
124   if (*p->name.full == '\0') {
125     snprintf(p->name.full, sizeof p->name.full, "%s:%d/udp",
126              inet_ntoa(dev->sock.sin_addr), ntohs(dev->sock.sin_port));
127     p->name.base = p->name.full;
128   }
129 
130   return ret;
131 }
132 
133 static void
134 udp_Free(struct physical *p)
135 {
136   struct udpdevice *dev = device2udp(p->handler);
137 
138   free(dev);
139 }
140 
141 static void
142 udp_device2iov(struct device *d, struct iovec *iov, int *niov,
143                int maxiov __unused, int *auxfd __unused, int *nauxfd __unused)
144 {
145   int sz = physical_MaxDeviceSize();
146 
147   iov[*niov].iov_base = realloc(d, sz);
148   if (iov[*niov].iov_base == NULL) {
149     log_Printf(LogALERT, "Failed to allocate memory: %d\n", sz);
150     AbortProgram(EX_OSERR);
151   }
152   iov[*niov].iov_len = sz;
153   (*niov)++;
154 }
155 
156 static const struct device baseudpdevice = {
157   UDP_DEVICE,
158   "udp",
159   0,
160   { CD_NOTREQUIRED, 0 },
161   NULL,
162   NULL,
163   NULL,
164   NULL,
165   NULL,
166   NULL,
167   NULL,
168   udp_Free,
169   udp_Recvfrom,
170   udp_Sendto,
171   udp_device2iov,
172   NULL,
173   NULL,
174   NULL
175 };
176 
177 struct device *
178 udp_iov2device(int type, struct physical *p, struct iovec *iov, int *niov,
179                int maxiov __unused, int *auxfd __unused, int *nauxfd __unused)
180 {
181   if (type == UDP_DEVICE) {
182     struct udpdevice *dev = (struct udpdevice *)iov[(*niov)++].iov_base;
183 
184     dev = realloc(dev, sizeof *dev);	/* Reduce to the correct size */
185     if (dev == NULL) {
186       log_Printf(LogALERT, "Failed to allocate memory: %d\n",
187                  (int)(sizeof *dev));
188       AbortProgram(EX_OSERR);
189     }
190 
191     /* Refresh function pointers etc */
192     memcpy(&dev->dev, &baseudpdevice, sizeof dev->dev);
193 
194     physical_SetupStack(p, dev->dev.name, PHYSICAL_FORCE_SYNC);
195     return &dev->dev;
196   }
197 
198   return NULL;
199 }
200 
201 static struct udpdevice *
202 udp_CreateDevice(struct physical *p, char *host, char *port)
203 {
204   struct udpdevice *dev;
205   struct servent *sp;
206 
207   if ((dev = malloc(sizeof *dev)) == NULL) {
208     log_Printf(LogWARN, "%s: Cannot allocate a udp device: %s\n",
209                p->link.name, strerror(errno));
210     return NULL;
211   }
212 
213   dev->sock.sin_family = AF_INET;
214   dev->sock.sin_addr = GetIpAddr(host);
215   if (dev->sock.sin_addr.s_addr == INADDR_NONE) {
216     log_Printf(LogWARN, "%s: %s: unknown host\n", p->link.name, host);
217     free(dev);
218     return NULL;
219   }
220   dev->sock.sin_port = htons(atoi(port));
221   if (dev->sock.sin_port == 0) {
222     sp = getservbyname(port, "udp");
223     if (sp)
224       dev->sock.sin_port = sp->s_port;
225     else {
226       log_Printf(LogWARN, "%s: %s: unknown service\n", p->link.name, port);
227       free(dev);
228       return NULL;
229     }
230   }
231 
232   log_Printf(LogPHASE, "%s: Connecting to %s:%s/udp\n", p->link.name,
233              host, port);
234 
235   p->fd = socket(PF_INET, SOCK_DGRAM, 0);
236   if (p->fd >= 0) {
237     log_Printf(LogDEBUG, "%s: Opened udp socket %s\n", p->link.name,
238                p->name.full);
239     if (connect(p->fd, (struct sockaddr *)&dev->sock, sizeof dev->sock) == 0) {
240       dev->connected = UDP_CONNECTED;
241       return dev;
242     } else
243       log_Printf(LogWARN, "%s: connect: %s\n", p->name.full, strerror(errno));
244   } else
245     log_Printf(LogWARN, "%s: socket: %s\n", p->name.full, strerror(errno));
246 
247   close(p->fd);
248   p->fd = -1;
249   free(dev);
250 
251   return NULL;
252 }
253 
254 struct device *
255 udp_Create(struct physical *p)
256 {
257   char *cp, *host, *port, *svc;
258   struct udpdevice *dev;
259 
260   dev = NULL;
261   if (p->fd < 0) {
262     if ((cp = strchr(p->name.full, ':')) != NULL && !strchr(cp + 1, ':')) {
263       *cp = '\0';
264       host = p->name.full;
265       port = cp + 1;
266       svc = strchr(port, '/');
267       if (svc && strcasecmp(svc, "/udp")) {
268         *cp = ':';
269         return NULL;
270       }
271       if (svc) {
272         p->fd--;     /* We own the device but maybe can't use it - change fd */
273         *svc = '\0';
274       }
275 
276       if (*host && *port)
277         dev = udp_CreateDevice(p, host, port);
278 
279       *cp = ':';
280       if (svc)
281         *svc = '/';
282     }
283   } else {
284     /* See if we're a connected udp socket */
285     struct stat st;
286 
287     if (fstat(p->fd, &st) != -1 && (st.st_mode & S_IFSOCK)) {
288       int type, sz;
289 
290       sz = sizeof type;
291       if (getsockopt(p->fd, SOL_SOCKET, SO_TYPE, &type, &sz) == -1) {
292         log_Printf(LogPHASE, "%s: Link is a closed socket !\n", p->link.name);
293         close(p->fd);
294         p->fd = -1;
295         return NULL;
296       }
297 
298       if (sz == sizeof type && type == SOCK_DGRAM) {
299         struct sockaddr_in sock;
300         struct sockaddr *sockp = (struct sockaddr *)&sock;
301 
302         if ((dev = malloc(sizeof *dev)) == NULL) {
303           log_Printf(LogWARN, "%s: Cannot allocate a udp device: %s\n",
304                      p->link.name, strerror(errno));
305           return NULL;
306         }
307 
308         if (getpeername(p->fd, sockp, &sz) == 0) {
309           log_Printf(LogPHASE, "%s: Link is a connected udp socket\n",
310                      p->link.name);
311           dev->connected = UDP_CONNECTED;
312 	} else {
313           log_Printf(LogPHASE, "%s: Link is a disconnected udp socket\n",
314                      p->link.name);
315 
316           dev->connected = UDP_MAYBEUNCONNECTED;
317 
318           if (p->link.lcp.cfg.openmode != OPEN_PASSIVE) {
319             log_Printf(LogPHASE, "%s:   Changing openmode to PASSIVE\n",
320                        p->link.name);
321             p->link.lcp.cfg.openmode = OPEN_PASSIVE;
322           }
323         }
324       }
325     }
326   }
327 
328   if (dev) {
329     memcpy(&dev->dev, &baseudpdevice, sizeof dev->dev);
330     physical_SetupStack(p, dev->dev.name, PHYSICAL_FORCE_SYNC);
331     if (p->cfg.cd.necessity != CD_DEFAULT)
332       log_Printf(LogWARN, "Carrier settings ignored\n");
333     return &dev->dev;
334   }
335 
336   return NULL;
337 }
338