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");