1 | /* |
---|
2 | * demand.c - Support routines for demand-dialling. |
---|
3 | * |
---|
4 | * Copyright (c) 1993 The Australian National University. |
---|
5 | * All rights reserved. |
---|
6 | * |
---|
7 | * Redistribution and use in source and binary forms are permitted |
---|
8 | * provided that the above copyright notice and this paragraph are |
---|
9 | * duplicated in all such forms and that any documentation, |
---|
10 | * advertising materials, and other materials related to such |
---|
11 | * distribution and use acknowledge that the software was developed |
---|
12 | * by the Australian National University. The name of the University |
---|
13 | * may not be used to endorse or promote products derived from this |
---|
14 | * software without specific prior written permission. |
---|
15 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
---|
16 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
---|
17 | * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
---|
18 | */ |
---|
19 | |
---|
20 | #ifndef lint |
---|
21 | /* static char rcsid[] = "$Id$"; */ |
---|
22 | #endif |
---|
23 | |
---|
24 | #include <stdio.h> |
---|
25 | #include <stdlib.h> |
---|
26 | #include <string.h> |
---|
27 | #include <errno.h> |
---|
28 | #include <fcntl.h> |
---|
29 | #include <syslog.h> |
---|
30 | #include <netdb.h> |
---|
31 | #include <sys/param.h> |
---|
32 | #include <sys/types.h> |
---|
33 | #include <sys/wait.h> |
---|
34 | #include <sys/time.h> |
---|
35 | #include <sys/resource.h> |
---|
36 | #include <sys/stat.h> |
---|
37 | #include <sys/socket.h> |
---|
38 | #ifdef PPP_FILTER |
---|
39 | #include <net/if.h> |
---|
40 | #include <net/bpf.h> |
---|
41 | #include <pcap.h> |
---|
42 | #endif |
---|
43 | |
---|
44 | #include "pppd.h" |
---|
45 | #include "fsm.h" |
---|
46 | #include "ipcp.h" |
---|
47 | #include "lcp.h" |
---|
48 | |
---|
49 | char *frame; |
---|
50 | int framelen; |
---|
51 | int framemax; |
---|
52 | int escape_flag; |
---|
53 | int flush_flag; |
---|
54 | int fcs; |
---|
55 | |
---|
56 | struct packet { |
---|
57 | int length; |
---|
58 | struct packet *next; |
---|
59 | unsigned char data[1]; |
---|
60 | }; |
---|
61 | |
---|
62 | struct packet *pend_q; |
---|
63 | struct packet *pend_qtail; |
---|
64 | |
---|
65 | static int active_packet __P((unsigned char *, int)); |
---|
66 | |
---|
67 | /* |
---|
68 | * demand_conf - configure the interface for doing dial-on-demand. |
---|
69 | */ |
---|
70 | void |
---|
71 | demand_conf() |
---|
72 | { |
---|
73 | int i; |
---|
74 | struct protent *protp; |
---|
75 | |
---|
76 | /* framemax = lcp_allowoptions[0].mru; |
---|
77 | if (framemax < PPP_MRU) */ |
---|
78 | framemax = PPP_MRU; |
---|
79 | framemax += PPP_HDRLEN + PPP_FCSLEN; |
---|
80 | frame = malloc(framemax); |
---|
81 | if (frame == NULL) |
---|
82 | novm("demand frame"); |
---|
83 | framelen = 0; |
---|
84 | pend_q = NULL; |
---|
85 | escape_flag = 0; |
---|
86 | flush_flag = 0; |
---|
87 | fcs = PPP_INITFCS; |
---|
88 | |
---|
89 | ppp_send_config(0, PPP_MRU, (u_int32_t) 0, 0, 0); |
---|
90 | ppp_recv_config(0, PPP_MRU, (u_int32_t) 0, 0, 0); |
---|
91 | |
---|
92 | #ifdef PPP_FILTER |
---|
93 | set_filters(&pass_filter, &active_filter); |
---|
94 | #endif |
---|
95 | |
---|
96 | /* |
---|
97 | * Call the demand_conf procedure for each protocol that's got one. |
---|
98 | */ |
---|
99 | for (i = 0; (protp = protocols[i]) != NULL; ++i) |
---|
100 | if (protp->enabled_flag && protp->demand_conf != NULL) |
---|
101 | if (!((*protp->demand_conf)(0))) |
---|
102 | die(1); |
---|
103 | } |
---|
104 | |
---|
105 | |
---|
106 | /* |
---|
107 | * demand_block - set each network protocol to block further packets. |
---|
108 | */ |
---|
109 | void |
---|
110 | demand_block() |
---|
111 | { |
---|
112 | int i; |
---|
113 | struct protent *protp; |
---|
114 | |
---|
115 | for (i = 0; (protp = protocols[i]) != NULL; ++i) |
---|
116 | if (protp->enabled_flag && protp->demand_conf != NULL) |
---|
117 | sifnpmode(0, protp->protocol & ~0x8000, NPMODE_QUEUE); |
---|
118 | get_loop_output(); |
---|
119 | } |
---|
120 | |
---|
121 | /* |
---|
122 | * demand_discard - set each network protocol to discard packets |
---|
123 | * with an error. |
---|
124 | */ |
---|
125 | void |
---|
126 | demand_discard() |
---|
127 | { |
---|
128 | struct packet *pkt, *nextpkt; |
---|
129 | int i; |
---|
130 | struct protent *protp; |
---|
131 | |
---|
132 | for (i = 0; (protp = protocols[i]) != NULL; ++i) |
---|
133 | if (protp->enabled_flag && protp->demand_conf != NULL) |
---|
134 | sifnpmode(0, protp->protocol & ~0x8000, NPMODE_ERROR); |
---|
135 | get_loop_output(); |
---|
136 | |
---|
137 | /* discard all saved packets */ |
---|
138 | for (pkt = pend_q; pkt != NULL; pkt = nextpkt) { |
---|
139 | nextpkt = pkt->next; |
---|
140 | free(pkt); |
---|
141 | } |
---|
142 | pend_q = NULL; |
---|
143 | framelen = 0; |
---|
144 | flush_flag = 0; |
---|
145 | escape_flag = 0; |
---|
146 | fcs = PPP_INITFCS; |
---|
147 | } |
---|
148 | |
---|
149 | /* |
---|
150 | * demand_unblock - set each enabled network protocol to pass packets. |
---|
151 | */ |
---|
152 | void |
---|
153 | demand_unblock() |
---|
154 | { |
---|
155 | int i; |
---|
156 | struct protent *protp; |
---|
157 | |
---|
158 | for (i = 0; (protp = protocols[i]) != NULL; ++i) |
---|
159 | if (protp->enabled_flag && protp->demand_conf != NULL) |
---|
160 | sifnpmode(0, protp->protocol & ~0x8000, NPMODE_PASS); |
---|
161 | } |
---|
162 | |
---|
163 | /* |
---|
164 | * FCS lookup table as calculated by genfcstab. |
---|
165 | */ |
---|
166 | static u_short fcstab[256] = { |
---|
167 | 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, |
---|
168 | 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, |
---|
169 | 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, |
---|
170 | 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, |
---|
171 | 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, |
---|
172 | 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, |
---|
173 | 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, |
---|
174 | 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, |
---|
175 | 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, |
---|
176 | 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, |
---|
177 | 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, |
---|
178 | 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, |
---|
179 | 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, |
---|
180 | 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, |
---|
181 | 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, |
---|
182 | 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, |
---|
183 | 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, |
---|
184 | 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, |
---|
185 | 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, |
---|
186 | 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, |
---|
187 | 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, |
---|
188 | 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, |
---|
189 | 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, |
---|
190 | 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, |
---|
191 | 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, |
---|
192 | 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, |
---|
193 | 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, |
---|
194 | 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, |
---|
195 | 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, |
---|
196 | 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, |
---|
197 | 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, |
---|
198 | 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 |
---|
199 | }; |
---|
200 | |
---|
201 | /* |
---|
202 | * loop_chars - process characters received from the loopback. |
---|
203 | * Calls loop_frame when a complete frame has been accumulated. |
---|
204 | * Return value is 1 if we need to bring up the link, 0 otherwise. |
---|
205 | */ |
---|
206 | int |
---|
207 | loop_chars(p, n) |
---|
208 | unsigned char *p; |
---|
209 | int n; |
---|
210 | { |
---|
211 | int c, rv; |
---|
212 | |
---|
213 | rv = 0; |
---|
214 | for (; n > 0; --n) { |
---|
215 | c = *p++; |
---|
216 | if (c == PPP_FLAG) { |
---|
217 | if (!escape_flag && !flush_flag |
---|
218 | && framelen > 2 && fcs == PPP_GOODFCS) { |
---|
219 | framelen -= 2; |
---|
220 | if (loop_frame(frame, framelen)) |
---|
221 | rv = 1; |
---|
222 | } |
---|
223 | framelen = 0; |
---|
224 | flush_flag = 0; |
---|
225 | escape_flag = 0; |
---|
226 | fcs = PPP_INITFCS; |
---|
227 | continue; |
---|
228 | } |
---|
229 | if (flush_flag) |
---|
230 | continue; |
---|
231 | if (escape_flag) { |
---|
232 | c ^= PPP_TRANS; |
---|
233 | escape_flag = 0; |
---|
234 | } else if (c == PPP_ESCAPE) { |
---|
235 | escape_flag = 1; |
---|
236 | continue; |
---|
237 | } |
---|
238 | if (framelen >= framemax) { |
---|
239 | flush_flag = 1; |
---|
240 | continue; |
---|
241 | } |
---|
242 | frame[framelen++] = c; |
---|
243 | fcs = PPP_FCS(fcs, c); |
---|
244 | } |
---|
245 | return rv; |
---|
246 | } |
---|
247 | |
---|
248 | /* |
---|
249 | * loop_frame - given a frame obtained from the loopback, |
---|
250 | * decide whether to bring up the link or not, and, if we want |
---|
251 | * to transmit this frame later, put it on the pending queue. |
---|
252 | * Return value is 1 if we need to bring up the link, 0 otherwise. |
---|
253 | * We assume that the kernel driver has already applied the |
---|
254 | * pass_filter, so we won't get packets it rejected. |
---|
255 | * We apply the active_filter to see if we want this packet to |
---|
256 | * bring up the link. |
---|
257 | */ |
---|
258 | int |
---|
259 | loop_frame(frame, len) |
---|
260 | unsigned char *frame; |
---|
261 | int len; |
---|
262 | { |
---|
263 | struct packet *pkt; |
---|
264 | |
---|
265 | /* log_packet(frame, len, "from loop: ", LOG_DEBUG); */ |
---|
266 | if (len < PPP_HDRLEN) |
---|
267 | return 0; |
---|
268 | if ((PPP_PROTOCOL(frame) & 0x8000) != 0) |
---|
269 | return 0; /* shouldn't get any of these anyway */ |
---|
270 | if (!active_packet(frame, len)) |
---|
271 | return 0; |
---|
272 | |
---|
273 | pkt = (struct packet *) malloc(sizeof(struct packet) + len); |
---|
274 | if (pkt != NULL) { |
---|
275 | pkt->length = len; |
---|
276 | pkt->next = NULL; |
---|
277 | memcpy(pkt->data, frame, len); |
---|
278 | if (pend_q == NULL) |
---|
279 | pend_q = pkt; |
---|
280 | else |
---|
281 | pend_qtail->next = pkt; |
---|
282 | pend_qtail = pkt; |
---|
283 | } |
---|
284 | return 1; |
---|
285 | } |
---|
286 | |
---|
287 | /* |
---|
288 | * demand_rexmit - Resend all those frames which we got via the |
---|
289 | * loopback, now that the real serial link is up. |
---|
290 | */ |
---|
291 | void |
---|
292 | demand_rexmit(proto) |
---|
293 | int proto; |
---|
294 | { |
---|
295 | struct packet *pkt, *prev, *nextpkt; |
---|
296 | |
---|
297 | prev = NULL; |
---|
298 | pkt = pend_q; |
---|
299 | pend_q = NULL; |
---|
300 | for (; pkt != NULL; pkt = nextpkt) { |
---|
301 | nextpkt = pkt->next; |
---|
302 | if (PPP_PROTOCOL(pkt->data) == proto) { |
---|
303 | output(0, pkt->data, pkt->length); |
---|
304 | free(pkt); |
---|
305 | } else { |
---|
306 | if (prev == NULL) |
---|
307 | pend_q = pkt; |
---|
308 | else |
---|
309 | prev->next = pkt; |
---|
310 | prev = pkt; |
---|
311 | } |
---|
312 | } |
---|
313 | pend_qtail = prev; |
---|
314 | if (prev != NULL) |
---|
315 | prev->next = NULL; |
---|
316 | } |
---|
317 | |
---|
318 | /* |
---|
319 | * Scan a packet to decide whether it is an "active" packet, |
---|
320 | * that is, whether it is worth bringing up the link for. |
---|
321 | */ |
---|
322 | static int |
---|
323 | active_packet(p, len) |
---|
324 | unsigned char *p; |
---|
325 | int len; |
---|
326 | { |
---|
327 | int proto, i; |
---|
328 | struct protent *protp; |
---|
329 | |
---|
330 | if (len < PPP_HDRLEN) |
---|
331 | return 0; |
---|
332 | proto = PPP_PROTOCOL(p); |
---|
333 | #ifdef PPP_FILTER |
---|
334 | if (active_filter.bf_len != 0 |
---|
335 | && bpf_filter(active_filter.bf_insns, frame, len, len) == 0) |
---|
336 | return 0; |
---|
337 | #endif |
---|
338 | for (i = 0; (protp = protocols[i]) != NULL; ++i) { |
---|
339 | if (protp->protocol < 0xC000 && (protp->protocol & ~0x8000) == proto) { |
---|
340 | if (!protp->enabled_flag) |
---|
341 | return 0; |
---|
342 | if (protp->active_pkt == NULL) |
---|
343 | return 1; |
---|
344 | return (*protp->active_pkt)(p, len); |
---|
345 | } |
---|
346 | } |
---|
347 | return 0; /* not a supported protocol !!?? */ |
---|
348 | } |
---|