blob: 771bab00754b0baff1a5c7a95892028857c8b84d [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * X.25 Packet Layer release 002
3 *
4 * This is ALPHA test software. This code may break your machine,
5 * randomly fail to work with new releases, misbehave and/or generally
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +09006 * screw up. It might even work.
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
8 * This code REQUIRES 2.1.15 or higher
9 *
10 * This module:
11 * This module is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 *
16 * History
17 * X.25 001 Split from x25_subr.c
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +090018 * mar/20/00 Daniela Squassoni Disabling/enabling of facilities
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 * negotiation.
Shaun Pereiraebc3f642005-06-22 22:16:17 -070020 * apr/14/05 Shaun Pereira - Allow fast select with no restriction
21 * on response.
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 */
23
24#include <linux/kernel.h>
25#include <linux/string.h>
26#include <linux/skbuff.h>
27#include <net/sock.h>
28#include <net/x25.h>
29
30/*
Shaun Pereiraa64b7b92006-03-22 00:01:31 -080031 * Parse a set of facilities into the facilities structures. Unrecognised
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 * facilities are written to the debug log file.
33 */
Shaun Pereiraa64b7b92006-03-22 00:01:31 -080034int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities,
35 struct x25_dte_facilities *dte_facs, unsigned long *vc_fac_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -070036{
37 unsigned char *p = skb->data;
John Hughesf5eb9172010-04-07 21:29:25 -070038 unsigned int len;
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
40 *vc_fac_mask = 0;
41
Shaun Pereiraa64b7b92006-03-22 00:01:31 -080042 /*
43 * The kernel knows which facilities were set on an incoming call but
44 * currently this information is not available to userspace. Here we
45 * give userspace who read incoming call facilities 0 length to indicate
46 * it wasn't set.
47 */
48 dte_facs->calling_len = 0;
49 dte_facs->called_len = 0;
50 memset(dte_facs->called_ae, '\0', sizeof(dte_facs->called_ae));
51 memset(dte_facs->calling_ae, '\0', sizeof(dte_facs->calling_ae));
52
John Hughesf5eb9172010-04-07 21:29:25 -070053 if (skb->len < 1)
54 return 0;
55
56 len = *p++;
57
58 if (len >= skb->len)
59 return -1;
60
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 while (len > 0) {
62 switch (*p & X25_FAC_CLASS_MASK) {
63 case X25_FAC_CLASS_A:
64 switch (*p) {
65 case X25_FAC_REVERSE:
Shaun Pereiraebc3f642005-06-22 22:16:17 -070066 if((p[1] & 0x81) == 0x81) {
67 facilities->reverse = p[1] & 0x81;
68 *vc_fac_mask |= X25_MASK_REVERSE;
69 break;
70 }
71
72 if((p[1] & 0x01) == 0x01) {
73 facilities->reverse = p[1] & 0x01;
74 *vc_fac_mask |= X25_MASK_REVERSE;
75 break;
76 }
77
78 if((p[1] & 0x80) == 0x80) {
79 facilities->reverse = p[1] & 0x80;
80 *vc_fac_mask |= X25_MASK_REVERSE;
81 break;
82 }
83
84 if(p[1] == 0x00) {
85 facilities->reverse
86 = X25_DEFAULT_REVERSE;
87 *vc_fac_mask |= X25_MASK_REVERSE;
88 break;
89 }
90
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 case X25_FAC_THROUGHPUT:
92 facilities->throughput = p[1];
93 *vc_fac_mask |= X25_MASK_THROUGHPUT;
94 break;
Shaun Pereiraa64b7b92006-03-22 00:01:31 -080095 case X25_MARKER:
96 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 default:
98 printk(KERN_DEBUG "X.25: unknown facility "
99 "%02X, value %02X\n",
100 p[0], p[1]);
101 break;
102 }
103 p += 2;
104 len -= 2;
105 break;
106 case X25_FAC_CLASS_B:
107 switch (*p) {
108 case X25_FAC_PACKET_SIZE:
109 facilities->pacsize_in = p[1];
110 facilities->pacsize_out = p[2];
111 *vc_fac_mask |= X25_MASK_PACKET_SIZE;
112 break;
113 case X25_FAC_WINDOW_SIZE:
114 facilities->winsize_in = p[1];
115 facilities->winsize_out = p[2];
116 *vc_fac_mask |= X25_MASK_WINDOW_SIZE;
117 break;
118 default:
119 printk(KERN_DEBUG "X.25: unknown facility "
120 "%02X, values %02X, %02X\n",
121 p[0], p[1], p[2]);
122 break;
123 }
124 p += 3;
125 len -= 3;
126 break;
127 case X25_FAC_CLASS_C:
128 printk(KERN_DEBUG "X.25: unknown facility %02X, "
129 "values %02X, %02X, %02X\n",
130 p[0], p[1], p[2], p[3]);
131 p += 4;
132 len -= 4;
133 break;
134 case X25_FAC_CLASS_D:
Shaun Pereiraa64b7b92006-03-22 00:01:31 -0800135 switch (*p) {
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +0900136 case X25_FAC_CALLING_AE:
137 if (p[1] > X25_MAX_DTE_FACIL_LEN)
Shaun Pereiraa64b7b92006-03-22 00:01:31 -0800138 break;
139 dte_facs->calling_len = p[2];
140 memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
141 *vc_fac_mask |= X25_MASK_CALLING_AE;
142 break;
143 case X25_FAC_CALLED_AE:
144 if (p[1] > X25_MAX_DTE_FACIL_LEN)
145 break;
146 dte_facs->called_len = p[2];
147 memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
148 *vc_fac_mask |= X25_MASK_CALLED_AE;
149 break;
150 default:
151 printk(KERN_DEBUG "X.25: unknown facility %02X,"
152 "length %d, values %02X, %02X, "
153 "%02X, %02X\n",
154 p[0], p[1], p[2], p[3], p[4], p[5]);
155 break;
156 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 len -= p[1] + 2;
Shaun Pereiraa64b7b92006-03-22 00:01:31 -0800158 p += p[1] + 2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 break;
160 }
161 }
162
163 return p - skb->data;
164}
165
166/*
167 * Create a set of facilities.
168 */
169int x25_create_facilities(unsigned char *buffer,
Shaun Pereiraa64b7b92006-03-22 00:01:31 -0800170 struct x25_facilities *facilities,
171 struct x25_dte_facilities *dte_facs, unsigned long facil_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172{
173 unsigned char *p = buffer + 1;
174 int len;
175
176 if (!facil_mask) {
177 /*
178 * Length of the facilities field in call_req or
179 * call_accept packets
180 */
181 buffer[0] = 0;
182 len = 1; /* 1 byte for the length field */
183 return len;
184 }
185
186 if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) {
187 *p++ = X25_FAC_REVERSE;
Shaun Pereiraebc3f642005-06-22 22:16:17 -0700188 *p++ = facilities->reverse;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 }
190
191 if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) {
192 *p++ = X25_FAC_THROUGHPUT;
193 *p++ = facilities->throughput;
194 }
195
196 if ((facilities->pacsize_in || facilities->pacsize_out) &&
197 (facil_mask & X25_MASK_PACKET_SIZE)) {
198 *p++ = X25_FAC_PACKET_SIZE;
199 *p++ = facilities->pacsize_in ? : facilities->pacsize_out;
200 *p++ = facilities->pacsize_out ? : facilities->pacsize_in;
201 }
202
203 if ((facilities->winsize_in || facilities->winsize_out) &&
204 (facil_mask & X25_MASK_WINDOW_SIZE)) {
205 *p++ = X25_FAC_WINDOW_SIZE;
206 *p++ = facilities->winsize_in ? : facilities->winsize_out;
207 *p++ = facilities->winsize_out ? : facilities->winsize_in;
208 }
209
Shaun Pereiraa64b7b92006-03-22 00:01:31 -0800210 if (facil_mask & (X25_MASK_CALLING_AE|X25_MASK_CALLED_AE)) {
211 *p++ = X25_MARKER;
212 *p++ = X25_DTE_SERVICES;
213 }
214
215 if (dte_facs->calling_len && (facil_mask & X25_MASK_CALLING_AE)) {
Eric Dumazet6bf15742008-01-13 22:27:52 -0800216 unsigned bytecount = (dte_facs->calling_len + 1) >> 1;
Shaun Pereiraa64b7b92006-03-22 00:01:31 -0800217 *p++ = X25_FAC_CALLING_AE;
218 *p++ = 1 + bytecount;
219 *p++ = dte_facs->calling_len;
220 memcpy(p, dte_facs->calling_ae, bytecount);
221 p += bytecount;
222 }
223
224 if (dte_facs->called_len && (facil_mask & X25_MASK_CALLED_AE)) {
225 unsigned bytecount = (dte_facs->called_len % 2) ?
226 dte_facs->called_len / 2 + 1 :
227 dte_facs->called_len / 2;
228 *p++ = X25_FAC_CALLED_AE;
229 *p++ = 1 + bytecount;
230 *p++ = dte_facs->called_len;
231 memcpy(p, dte_facs->called_ae, bytecount);
232 p+=bytecount;
233 }
234
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 len = p - buffer;
236 buffer[0] = len - 1;
237
238 return len;
239}
240
241/*
242 * Try to reach a compromise on a set of facilities.
243 *
244 * The only real problem is with reverse charging.
245 */
246int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk,
Shaun Pereiraa64b7b92006-03-22 00:01:31 -0800247 struct x25_facilities *new, struct x25_dte_facilities *dte)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248{
249 struct x25_sock *x25 = x25_sk(sk);
250 struct x25_facilities *ours = &x25->facilities;
251 struct x25_facilities theirs;
252 int len;
253
254 memset(&theirs, 0, sizeof(theirs));
255 memcpy(new, ours, sizeof(*new));
256
Shaun Pereiraa64b7b92006-03-22 00:01:31 -0800257 len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
John Hughesf5eb9172010-04-07 21:29:25 -0700258 if (len < 0)
259 return len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
261 /*
262 * They want reverse charging, we won't accept it.
263 */
Shaun Pereiraebc3f642005-06-22 22:16:17 -0700264 if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) {
Andrew Hendryd2e75432007-01-04 17:00:56 -0800265 SOCK_DEBUG(sk, "X.25: rejecting reverse charging request\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 return -1;
267 }
268
269 new->reverse = theirs.reverse;
270
271 if (theirs.throughput) {
John Hughesddd04512010-04-04 06:48:10 +0000272 int theirs_in = theirs.throughput & 0x0f;
273 int theirs_out = theirs.throughput & 0xf0;
274 int ours_in = ours->throughput & 0x0f;
275 int ours_out = ours->throughput & 0xf0;
276 if (!ours_in || theirs_in < ours_in) {
277 SOCK_DEBUG(sk, "X.25: inbound throughput negotiated\n");
278 new->throughput = (new->throughput & 0xf0) | theirs_in;
279 }
280 if (!ours_out || theirs_out < ours_out) {
281 SOCK_DEBUG(sk,
282 "X.25: outbound throughput negotiated\n");
283 new->throughput = (new->throughput & 0x0f) | theirs_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 }
285 }
286
287 if (theirs.pacsize_in && theirs.pacsize_out) {
288 if (theirs.pacsize_in < ours->pacsize_in) {
Andrew Hendryd2e75432007-01-04 17:00:56 -0800289 SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 new->pacsize_in = theirs.pacsize_in;
291 }
292 if (theirs.pacsize_out < ours->pacsize_out) {
Andrew Hendryd2e75432007-01-04 17:00:56 -0800293 SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 new->pacsize_out = theirs.pacsize_out;
295 }
296 }
297
298 if (theirs.winsize_in && theirs.winsize_out) {
299 if (theirs.winsize_in < ours->winsize_in) {
Andrew Hendryd2e75432007-01-04 17:00:56 -0800300 SOCK_DEBUG(sk, "X.25: window size inwards negotiated down\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 new->winsize_in = theirs.winsize_in;
302 }
303 if (theirs.winsize_out < ours->winsize_out) {
Andrew Hendryd2e75432007-01-04 17:00:56 -0800304 SOCK_DEBUG(sk, "X.25: window size outwards negotiated down\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 new->winsize_out = theirs.winsize_out;
306 }
307 }
308
309 return len;
310}
311
312/*
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +0900313 * Limit values of certain facilities according to the capability of the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 * currently attached x25 link.
315 */
316void x25_limit_facilities(struct x25_facilities *facilities,
317 struct x25_neigh *nb)
318{
319
320 if (!nb->extended) {
321 if (facilities->winsize_in > 7) {
322 printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n");
323 facilities->winsize_in = 7;
324 }
325 if (facilities->winsize_out > 7) {
326 facilities->winsize_out = 7;
327 printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n");
328 }
329 }
330}