2 * X.25 Packet Layer release 002
4 * This is ALPHA test software. This code may break your machine,
5 * randomly fail to work with new releases, misbehave and/or generally
6 * screw up. It might even work.
8 * This code REQUIRES 2.1.15 or higher
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.
17 * X.25 001 Split from x25_subr.c
18 * mar/20/00 Daniela Squassoni Disabling/enabling of facilities
20 * apr/14/05 Shaun Pereira - Allow fast select with no restriction
24 #include <linux/kernel.h>
25 #include <linux/string.h>
26 #include <linux/skbuff.h>
31 * Parse a set of facilities into the facilities structures. Unrecognised
32 * facilities are written to the debug log file.
34 int x25_parse_facilities(struct sk_buff
*skb
, struct x25_facilities
*facilities
,
35 struct x25_dte_facilities
*dte_facs
, unsigned long *vc_fac_mask
)
37 unsigned char *p
= skb
->data
;
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
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
));
62 switch (*p
& X25_FAC_CLASS_MASK
) {
68 if((p
[1] & 0x81) == 0x81) {
69 facilities
->reverse
= p
[1] & 0x81;
70 *vc_fac_mask
|= X25_MASK_REVERSE
;
74 if((p
[1] & 0x01) == 0x01) {
75 facilities
->reverse
= p
[1] & 0x01;
76 *vc_fac_mask
|= X25_MASK_REVERSE
;
80 if((p
[1] & 0x80) == 0x80) {
81 facilities
->reverse
= p
[1] & 0x80;
82 *vc_fac_mask
|= X25_MASK_REVERSE
;
88 = X25_DEFAULT_REVERSE
;
89 *vc_fac_mask
|= X25_MASK_REVERSE
;
93 case X25_FAC_THROUGHPUT
:
94 facilities
->throughput
= p
[1];
95 *vc_fac_mask
|= X25_MASK_THROUGHPUT
;
100 printk(KERN_DEBUG
"X.25: unknown facility "
101 "%02X, value %02X\n",
108 case X25_FAC_CLASS_B
:
112 case X25_FAC_PACKET_SIZE
:
113 facilities
->pacsize_in
= p
[1];
114 facilities
->pacsize_out
= p
[2];
115 *vc_fac_mask
|= X25_MASK_PACKET_SIZE
;
117 case X25_FAC_WINDOW_SIZE
:
118 facilities
->winsize_in
= p
[1];
119 facilities
->winsize_out
= p
[2];
120 *vc_fac_mask
|= X25_MASK_WINDOW_SIZE
;
123 printk(KERN_DEBUG
"X.25: unknown facility "
124 "%02X, values %02X, %02X\n",
131 case X25_FAC_CLASS_C
:
134 printk(KERN_DEBUG
"X.25: unknown facility %02X, "
135 "values %02X, %02X, %02X\n",
136 p
[0], p
[1], p
[2], p
[3]);
140 case X25_FAC_CLASS_D
:
144 case X25_FAC_CALLING_AE
:
145 if (p
[1] > X25_MAX_DTE_FACIL_LEN
|| p
[1] <= 1)
147 dte_facs
->calling_len
= p
[2];
148 memcpy(dte_facs
->calling_ae
, &p
[3], p
[1] - 1);
149 *vc_fac_mask
|= X25_MASK_CALLING_AE
;
151 case X25_FAC_CALLED_AE
:
152 if (p
[1] > X25_MAX_DTE_FACIL_LEN
|| p
[1] <= 1)
154 dte_facs
->called_len
= p
[2];
155 memcpy(dte_facs
->called_ae
, &p
[3], p
[1] - 1);
156 *vc_fac_mask
|= X25_MASK_CALLED_AE
;
159 printk(KERN_DEBUG
"X.25: unknown facility %02X,"
160 "length %d\n", p
[0], p
[1]);
169 return p
- skb
->data
;
173 * Create a set of facilities.
175 int x25_create_facilities(unsigned char *buffer
,
176 struct x25_facilities
*facilities
,
177 struct x25_dte_facilities
*dte_facs
, unsigned long facil_mask
)
179 unsigned char *p
= buffer
+ 1;
184 * Length of the facilities field in call_req or
185 * call_accept packets
188 len
= 1; /* 1 byte for the length field */
192 if (facilities
->reverse
&& (facil_mask
& X25_MASK_REVERSE
)) {
193 *p
++ = X25_FAC_REVERSE
;
194 *p
++ = facilities
->reverse
;
197 if (facilities
->throughput
&& (facil_mask
& X25_MASK_THROUGHPUT
)) {
198 *p
++ = X25_FAC_THROUGHPUT
;
199 *p
++ = facilities
->throughput
;
202 if ((facilities
->pacsize_in
|| facilities
->pacsize_out
) &&
203 (facil_mask
& X25_MASK_PACKET_SIZE
)) {
204 *p
++ = X25_FAC_PACKET_SIZE
;
205 *p
++ = facilities
->pacsize_in
? : facilities
->pacsize_out
;
206 *p
++ = facilities
->pacsize_out
? : facilities
->pacsize_in
;
209 if ((facilities
->winsize_in
|| facilities
->winsize_out
) &&
210 (facil_mask
& X25_MASK_WINDOW_SIZE
)) {
211 *p
++ = X25_FAC_WINDOW_SIZE
;
212 *p
++ = facilities
->winsize_in
? : facilities
->winsize_out
;
213 *p
++ = facilities
->winsize_out
? : facilities
->winsize_in
;
216 if (facil_mask
& (X25_MASK_CALLING_AE
|X25_MASK_CALLED_AE
)) {
218 *p
++ = X25_DTE_SERVICES
;
221 if (dte_facs
->calling_len
&& (facil_mask
& X25_MASK_CALLING_AE
)) {
222 unsigned bytecount
= (dte_facs
->calling_len
+ 1) >> 1;
223 *p
++ = X25_FAC_CALLING_AE
;
224 *p
++ = 1 + bytecount
;
225 *p
++ = dte_facs
->calling_len
;
226 memcpy(p
, dte_facs
->calling_ae
, bytecount
);
230 if (dte_facs
->called_len
&& (facil_mask
& X25_MASK_CALLED_AE
)) {
231 unsigned bytecount
= (dte_facs
->called_len
% 2) ?
232 dte_facs
->called_len
/ 2 + 1 :
233 dte_facs
->called_len
/ 2;
234 *p
++ = X25_FAC_CALLED_AE
;
235 *p
++ = 1 + bytecount
;
236 *p
++ = dte_facs
->called_len
;
237 memcpy(p
, dte_facs
->called_ae
, bytecount
);
248 * Try to reach a compromise on a set of facilities.
250 * The only real problem is with reverse charging.
252 int x25_negotiate_facilities(struct sk_buff
*skb
, struct sock
*sk
,
253 struct x25_facilities
*new, struct x25_dte_facilities
*dte
)
255 struct x25_sock
*x25
= x25_sk(sk
);
256 struct x25_facilities
*ours
= &x25
->facilities
;
257 struct x25_facilities theirs
;
260 memset(&theirs
, 0, sizeof(theirs
));
261 memcpy(new, ours
, sizeof(*new));
263 len
= x25_parse_facilities(skb
, &theirs
, dte
, &x25
->vc_facil_mask
);
268 * They want reverse charging, we won't accept it.
270 if ((theirs
.reverse
& 0x01 ) && (ours
->reverse
& 0x01)) {
271 SOCK_DEBUG(sk
, "X.25: rejecting reverse charging request\n");
275 new->reverse
= theirs
.reverse
;
277 if (theirs
.throughput
) {
278 int theirs_in
= theirs
.throughput
& 0x0f;
279 int theirs_out
= theirs
.throughput
& 0xf0;
280 int ours_in
= ours
->throughput
& 0x0f;
281 int ours_out
= ours
->throughput
& 0xf0;
282 if (!ours_in
|| theirs_in
< ours_in
) {
283 SOCK_DEBUG(sk
, "X.25: inbound throughput negotiated\n");
284 new->throughput
= (new->throughput
& 0xf0) | theirs_in
;
286 if (!ours_out
|| theirs_out
< ours_out
) {
288 "X.25: outbound throughput negotiated\n");
289 new->throughput
= (new->throughput
& 0x0f) | theirs_out
;
293 if (theirs
.pacsize_in
&& theirs
.pacsize_out
) {
294 if (theirs
.pacsize_in
< ours
->pacsize_in
) {
295 SOCK_DEBUG(sk
, "X.25: packet size inwards negotiated down\n");
296 new->pacsize_in
= theirs
.pacsize_in
;
298 if (theirs
.pacsize_out
< ours
->pacsize_out
) {
299 SOCK_DEBUG(sk
, "X.25: packet size outwards negotiated down\n");
300 new->pacsize_out
= theirs
.pacsize_out
;
304 if (theirs
.winsize_in
&& theirs
.winsize_out
) {
305 if (theirs
.winsize_in
< ours
->winsize_in
) {
306 SOCK_DEBUG(sk
, "X.25: window size inwards negotiated down\n");
307 new->winsize_in
= theirs
.winsize_in
;
309 if (theirs
.winsize_out
< ours
->winsize_out
) {
310 SOCK_DEBUG(sk
, "X.25: window size outwards negotiated down\n");
311 new->winsize_out
= theirs
.winsize_out
;
319 * Limit values of certain facilities according to the capability of the
320 * currently attached x25 link.
322 void x25_limit_facilities(struct x25_facilities
*facilities
,
323 struct x25_neigh
*nb
)
327 if (facilities
->winsize_in
> 7) {
328 printk(KERN_DEBUG
"X.25: incoming winsize limited to 7\n");
329 facilities
->winsize_in
= 7;
331 if (facilities
->winsize_out
> 7) {
332 facilities
->winsize_out
= 7;
333 printk( KERN_DEBUG
"X.25: outgoing winsize limited to 7\n");
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