Merge tag 'v3.10.102' into update
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / x25 / x25_facilities.c
CommitLineData
1da177e4
LT
1/*
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
f8e1d201 6 * screw up. It might even work.
1da177e4
LT
7 *
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
f8e1d201 18 * mar/20/00 Daniela Squassoni Disabling/enabling of facilities
1da177e4 19 * negotiation.
ebc3f64b
SP
20 * apr/14/05 Shaun Pereira - Allow fast select with no restriction
21 * on response.
1da177e4
LT
22 */
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
95c30430 30/**
31 * x25_parse_facilities - Parse facilities from skb into the facilities structs
32 *
33 * @skb: sk_buff to parse
25985edc 34 * @facilities: Regular facilities, updated as facilities are found
95c30430 35 * @dte_facs: ITU DTE facilities, updated as DTE facilities are found
36 * @vc_fac_mask: mask is updated with all facilities found
37 *
38 * Return codes:
39 * -1 - Parsing error, caller should drop call and clean up
40 * 0 - Parse OK, this skb has no facilities
41 * >0 - Parse OK, returns the length of the facilities header
42 *
1da177e4 43 */
a64b7b93
SP
44int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities,
45 struct x25_dte_facilities *dte_facs, unsigned long *vc_fac_mask)
1da177e4 46{
cb101ed2 47 unsigned char *p;
f5eb917b 48 unsigned int len;
1da177e4
LT
49
50 *vc_fac_mask = 0;
51
a64b7b93
SP
52 /*
53 * The kernel knows which facilities were set on an incoming call but
54 * currently this information is not available to userspace. Here we
55 * give userspace who read incoming call facilities 0 length to indicate
56 * it wasn't set.
57 */
58 dte_facs->calling_len = 0;
59 dte_facs->called_len = 0;
60 memset(dte_facs->called_ae, '\0', sizeof(dte_facs->called_ae));
61 memset(dte_facs->calling_ae, '\0', sizeof(dte_facs->calling_ae));
62
cb101ed2 63 if (!pskb_may_pull(skb, 1))
f5eb917b
JH
64 return 0;
65
cb101ed2 66 len = skb->data[0];
f5eb917b 67
cb101ed2 68 if (!pskb_may_pull(skb, 1 + len))
f5eb917b
JH
69 return -1;
70
cb101ed2
MD
71 p = skb->data + 1;
72
1da177e4
LT
73 while (len > 0) {
74 switch (*p & X25_FAC_CLASS_MASK) {
75 case X25_FAC_CLASS_A:
5ef41308 76 if (len < 2)
95c30430 77 return -1;
1da177e4
LT
78 switch (*p) {
79 case X25_FAC_REVERSE:
ebc3f64b
SP
80 if((p[1] & 0x81) == 0x81) {
81 facilities->reverse = p[1] & 0x81;
82 *vc_fac_mask |= X25_MASK_REVERSE;
83 break;
84 }
85
86 if((p[1] & 0x01) == 0x01) {
87 facilities->reverse = p[1] & 0x01;
88 *vc_fac_mask |= X25_MASK_REVERSE;
89 break;
90 }
91
92 if((p[1] & 0x80) == 0x80) {
93 facilities->reverse = p[1] & 0x80;
94 *vc_fac_mask |= X25_MASK_REVERSE;
95 break;
96 }
97
98 if(p[1] == 0x00) {
99 facilities->reverse
100 = X25_DEFAULT_REVERSE;
101 *vc_fac_mask |= X25_MASK_REVERSE;
102 break;
103 }
104
1da177e4
LT
105 case X25_FAC_THROUGHPUT:
106 facilities->throughput = p[1];
107 *vc_fac_mask |= X25_MASK_THROUGHPUT;
108 break;
a64b7b93
SP
109 case X25_MARKER:
110 break;
1da177e4
LT
111 default:
112 printk(KERN_DEBUG "X.25: unknown facility "
113 "%02X, value %02X\n",
114 p[0], p[1]);
115 break;
116 }
117 p += 2;
118 len -= 2;
119 break;
120 case X25_FAC_CLASS_B:
5ef41308 121 if (len < 3)
95c30430 122 return -1;
1da177e4
LT
123 switch (*p) {
124 case X25_FAC_PACKET_SIZE:
125 facilities->pacsize_in = p[1];
126 facilities->pacsize_out = p[2];
127 *vc_fac_mask |= X25_MASK_PACKET_SIZE;
128 break;
129 case X25_FAC_WINDOW_SIZE:
130 facilities->winsize_in = p[1];
131 facilities->winsize_out = p[2];
132 *vc_fac_mask |= X25_MASK_WINDOW_SIZE;
133 break;
134 default:
135 printk(KERN_DEBUG "X.25: unknown facility "
136 "%02X, values %02X, %02X\n",
137 p[0], p[1], p[2]);
138 break;
139 }
140 p += 3;
141 len -= 3;
142 break;
143 case X25_FAC_CLASS_C:
5ef41308 144 if (len < 4)
95c30430 145 return -1;
1da177e4
LT
146 printk(KERN_DEBUG "X.25: unknown facility %02X, "
147 "values %02X, %02X, %02X\n",
148 p[0], p[1], p[2], p[3]);
149 p += 4;
150 len -= 4;
151 break;
152 case X25_FAC_CLASS_D:
5ef41308 153 if (len < p[1] + 2)
95c30430 154 return -1;
a64b7b93 155 switch (*p) {
f8e1d201 156 case X25_FAC_CALLING_AE:
a6331d6f 157 if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
95c30430 158 return -1;
a64b7b93
SP
159 dte_facs->calling_len = p[2];
160 memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
161 *vc_fac_mask |= X25_MASK_CALLING_AE;
162 break;
163 case X25_FAC_CALLED_AE:
a6331d6f 164 if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
95c30430 165 return -1;
a64b7b93
SP
166 dte_facs->called_len = p[2];
167 memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
168 *vc_fac_mask |= X25_MASK_CALLED_AE;
169 break;
170 default:
171 printk(KERN_DEBUG "X.25: unknown facility %02X,"
5ef41308 172 "length %d\n", p[0], p[1]);
a64b7b93
SP
173 break;
174 }
1da177e4 175 len -= p[1] + 2;
a64b7b93 176 p += p[1] + 2;
1da177e4
LT
177 break;
178 }
179 }
180
181 return p - skb->data;
182}
183
184/*
185 * Create a set of facilities.
186 */
187int x25_create_facilities(unsigned char *buffer,
a64b7b93
SP
188 struct x25_facilities *facilities,
189 struct x25_dte_facilities *dte_facs, unsigned long facil_mask)
1da177e4
LT
190{
191 unsigned char *p = buffer + 1;
192 int len;
193
194 if (!facil_mask) {
195 /*
196 * Length of the facilities field in call_req or
197 * call_accept packets
198 */
199 buffer[0] = 0;
200 len = 1; /* 1 byte for the length field */
201 return len;
202 }
203
204 if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) {
205 *p++ = X25_FAC_REVERSE;
ebc3f64b 206 *p++ = facilities->reverse;
1da177e4
LT
207 }
208
209 if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) {
210 *p++ = X25_FAC_THROUGHPUT;
211 *p++ = facilities->throughput;
212 }
213
214 if ((facilities->pacsize_in || facilities->pacsize_out) &&
215 (facil_mask & X25_MASK_PACKET_SIZE)) {
216 *p++ = X25_FAC_PACKET_SIZE;
217 *p++ = facilities->pacsize_in ? : facilities->pacsize_out;
218 *p++ = facilities->pacsize_out ? : facilities->pacsize_in;
219 }
220
221 if ((facilities->winsize_in || facilities->winsize_out) &&
222 (facil_mask & X25_MASK_WINDOW_SIZE)) {
223 *p++ = X25_FAC_WINDOW_SIZE;
224 *p++ = facilities->winsize_in ? : facilities->winsize_out;
225 *p++ = facilities->winsize_out ? : facilities->winsize_in;
226 }
227
a64b7b93
SP
228 if (facil_mask & (X25_MASK_CALLING_AE|X25_MASK_CALLED_AE)) {
229 *p++ = X25_MARKER;
230 *p++ = X25_DTE_SERVICES;
231 }
232
233 if (dte_facs->calling_len && (facil_mask & X25_MASK_CALLING_AE)) {
95c96174 234 unsigned int bytecount = (dte_facs->calling_len + 1) >> 1;
a64b7b93
SP
235 *p++ = X25_FAC_CALLING_AE;
236 *p++ = 1 + bytecount;
237 *p++ = dte_facs->calling_len;
238 memcpy(p, dte_facs->calling_ae, bytecount);
239 p += bytecount;
240 }
241
242 if (dte_facs->called_len && (facil_mask & X25_MASK_CALLED_AE)) {
95c96174 243 unsigned int bytecount = (dte_facs->called_len % 2) ?
a64b7b93
SP
244 dte_facs->called_len / 2 + 1 :
245 dte_facs->called_len / 2;
246 *p++ = X25_FAC_CALLED_AE;
247 *p++ = 1 + bytecount;
248 *p++ = dte_facs->called_len;
249 memcpy(p, dte_facs->called_ae, bytecount);
250 p+=bytecount;
251 }
252
1da177e4
LT
253 len = p - buffer;
254 buffer[0] = len - 1;
255
256 return len;
257}
258
259/*
260 * Try to reach a compromise on a set of facilities.
261 *
262 * The only real problem is with reverse charging.
263 */
264int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk,
a64b7b93 265 struct x25_facilities *new, struct x25_dte_facilities *dte)
1da177e4
LT
266{
267 struct x25_sock *x25 = x25_sk(sk);
268 struct x25_facilities *ours = &x25->facilities;
269 struct x25_facilities theirs;
270 int len;
271
272 memset(&theirs, 0, sizeof(theirs));
273 memcpy(new, ours, sizeof(*new));
ee78aa28 274 memset(dte, 0, sizeof(*dte));
1da177e4 275
a64b7b93 276 len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
f5eb917b
JH
277 if (len < 0)
278 return len;
1da177e4
LT
279
280 /*
281 * They want reverse charging, we won't accept it.
282 */
ebc3f64b 283 if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) {
d2e7543c 284 SOCK_DEBUG(sk, "X.25: rejecting reverse charging request\n");
1da177e4
LT
285 return -1;
286 }
287
288 new->reverse = theirs.reverse;
289
290 if (theirs.throughput) {
ddd0451f
JH
291 int theirs_in = theirs.throughput & 0x0f;
292 int theirs_out = theirs.throughput & 0xf0;
293 int ours_in = ours->throughput & 0x0f;
294 int ours_out = ours->throughput & 0xf0;
295 if (!ours_in || theirs_in < ours_in) {
296 SOCK_DEBUG(sk, "X.25: inbound throughput negotiated\n");
297 new->throughput = (new->throughput & 0xf0) | theirs_in;
298 }
299 if (!ours_out || theirs_out < ours_out) {
300 SOCK_DEBUG(sk,
301 "X.25: outbound throughput negotiated\n");
302 new->throughput = (new->throughput & 0x0f) | theirs_out;
1da177e4
LT
303 }
304 }
305
306 if (theirs.pacsize_in && theirs.pacsize_out) {
307 if (theirs.pacsize_in < ours->pacsize_in) {
d2e7543c 308 SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down\n");
1da177e4
LT
309 new->pacsize_in = theirs.pacsize_in;
310 }
311 if (theirs.pacsize_out < ours->pacsize_out) {
d2e7543c 312 SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down\n");
1da177e4
LT
313 new->pacsize_out = theirs.pacsize_out;
314 }
315 }
316
317 if (theirs.winsize_in && theirs.winsize_out) {
318 if (theirs.winsize_in < ours->winsize_in) {
d2e7543c 319 SOCK_DEBUG(sk, "X.25: window size inwards negotiated down\n");
1da177e4
LT
320 new->winsize_in = theirs.winsize_in;
321 }
322 if (theirs.winsize_out < ours->winsize_out) {
d2e7543c 323 SOCK_DEBUG(sk, "X.25: window size outwards negotiated down\n");
1da177e4
LT
324 new->winsize_out = theirs.winsize_out;
325 }
326 }
327
328 return len;
329}
330
331/*
f8e1d201 332 * Limit values of certain facilities according to the capability of the
1da177e4
LT
333 * currently attached x25 link.
334 */
335void x25_limit_facilities(struct x25_facilities *facilities,
336 struct x25_neigh *nb)
337{
338
339 if (!nb->extended) {
340 if (facilities->winsize_in > 7) {
341 printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n");
342 facilities->winsize_in = 7;
343 }
344 if (facilities->winsize_out > 7) {
345 facilities->winsize_out = 7;
346 printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n");
347 }
348 }
349}