[NET] X25: Fix whitespace errors.
[linux-3.10.git] / net / x25 / x25_facilities.c
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
6  *      screw up. It might even work.
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
18  *      mar/20/00       Daniela Squassoni Disabling/enabling of facilities
19  *                                        negotiation.
20  *      apr/14/05       Shaun Pereira - Allow fast select with no restriction
21  *                                      on response.
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
30 /*
31  * Parse a set of facilities into the facilities structures. Unrecognised
32  *      facilities are written to the debug log file.
33  */
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)
36 {
37         unsigned char *p = skb->data;
38         unsigned int len = *p++;
39
40         *vc_fac_mask = 0;
41
42         /*
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
53         while (len > 0) {
54                 switch (*p & X25_FAC_CLASS_MASK) {
55                 case X25_FAC_CLASS_A:
56                         switch (*p) {
57                         case X25_FAC_REVERSE:
58                                 if((p[1] & 0x81) == 0x81) {
59                                         facilities->reverse = p[1] & 0x81;
60                                         *vc_fac_mask |= X25_MASK_REVERSE;
61                                         break;
62                                 }
63
64                                 if((p[1] & 0x01) == 0x01) {
65                                         facilities->reverse = p[1] & 0x01;
66                                         *vc_fac_mask |= X25_MASK_REVERSE;
67                                         break;
68                                 }
69
70                                 if((p[1] & 0x80) == 0x80) {
71                                         facilities->reverse = p[1] & 0x80;
72                                         *vc_fac_mask |= X25_MASK_REVERSE;
73                                         break;
74                                 }
75
76                                 if(p[1] == 0x00) {
77                                         facilities->reverse
78                                                 = X25_DEFAULT_REVERSE;
79                                         *vc_fac_mask |= X25_MASK_REVERSE;
80                                         break;
81                                 }
82
83                         case X25_FAC_THROUGHPUT:
84                                 facilities->throughput = p[1];
85                                 *vc_fac_mask |= X25_MASK_THROUGHPUT;
86                                 break;
87                         case X25_MARKER:
88                                 break;
89                         default:
90                                 printk(KERN_DEBUG "X.25: unknown facility "
91                                        "%02X, value %02X\n",
92                                        p[0], p[1]);
93                                 break;
94                         }
95                         p   += 2;
96                         len -= 2;
97                         break;
98                 case X25_FAC_CLASS_B:
99                         switch (*p) {
100                         case X25_FAC_PACKET_SIZE:
101                                 facilities->pacsize_in  = p[1];
102                                 facilities->pacsize_out = p[2];
103                                 *vc_fac_mask |= X25_MASK_PACKET_SIZE;
104                                 break;
105                         case X25_FAC_WINDOW_SIZE:
106                                 facilities->winsize_in  = p[1];
107                                 facilities->winsize_out = p[2];
108                                 *vc_fac_mask |= X25_MASK_WINDOW_SIZE;
109                                 break;
110                         default:
111                                 printk(KERN_DEBUG "X.25: unknown facility "
112                                        "%02X, values %02X, %02X\n",
113                                        p[0], p[1], p[2]);
114                                 break;
115                         }
116                         p   += 3;
117                         len -= 3;
118                         break;
119                 case X25_FAC_CLASS_C:
120                         printk(KERN_DEBUG "X.25: unknown facility %02X, "
121                                "values %02X, %02X, %02X\n",
122                                p[0], p[1], p[2], p[3]);
123                         p   += 4;
124                         len -= 4;
125                         break;
126                 case X25_FAC_CLASS_D:
127                         switch (*p) {
128                         case X25_FAC_CALLING_AE:
129                                 if (p[1] > X25_MAX_DTE_FACIL_LEN)
130                                         break;
131                                 dte_facs->calling_len = p[2];
132                                 memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
133                                 *vc_fac_mask |= X25_MASK_CALLING_AE;
134                                 break;
135                         case X25_FAC_CALLED_AE:
136                                 if (p[1] > X25_MAX_DTE_FACIL_LEN)
137                                         break;
138                                 dte_facs->called_len = p[2];
139                                 memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
140                                 *vc_fac_mask |= X25_MASK_CALLED_AE;
141                                 break;
142                         default:
143                                 printk(KERN_DEBUG "X.25: unknown facility %02X,"
144                                         "length %d, values %02X, %02X, "
145                                         "%02X, %02X\n",
146                                         p[0], p[1], p[2], p[3], p[4], p[5]);
147                                 break;
148                         }
149                         len -= p[1] + 2;
150                         p += p[1] + 2;
151                         break;
152                 }
153         }
154
155         return p - skb->data;
156 }
157
158 /*
159  *      Create a set of facilities.
160  */
161 int x25_create_facilities(unsigned char *buffer,
162                 struct x25_facilities *facilities,
163                 struct x25_dte_facilities *dte_facs, unsigned long facil_mask)
164 {
165         unsigned char *p = buffer + 1;
166         int len;
167
168         if (!facil_mask) {
169                 /*
170                  * Length of the facilities field in call_req or
171                  * call_accept packets
172                  */
173                 buffer[0] = 0;
174                 len = 1; /* 1 byte for the length field */
175                 return len;
176         }
177
178         if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) {
179                 *p++ = X25_FAC_REVERSE;
180                 *p++ = facilities->reverse;
181         }
182
183         if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) {
184                 *p++ = X25_FAC_THROUGHPUT;
185                 *p++ = facilities->throughput;
186         }
187
188         if ((facilities->pacsize_in || facilities->pacsize_out) &&
189             (facil_mask & X25_MASK_PACKET_SIZE)) {
190                 *p++ = X25_FAC_PACKET_SIZE;
191                 *p++ = facilities->pacsize_in ? : facilities->pacsize_out;
192                 *p++ = facilities->pacsize_out ? : facilities->pacsize_in;
193         }
194
195         if ((facilities->winsize_in || facilities->winsize_out) &&
196             (facil_mask & X25_MASK_WINDOW_SIZE)) {
197                 *p++ = X25_FAC_WINDOW_SIZE;
198                 *p++ = facilities->winsize_in ? : facilities->winsize_out;
199                 *p++ = facilities->winsize_out ? : facilities->winsize_in;
200         }
201
202         if (facil_mask & (X25_MASK_CALLING_AE|X25_MASK_CALLED_AE)) {
203                 *p++ = X25_MARKER;
204                 *p++ = X25_DTE_SERVICES;
205         }
206
207         if (dte_facs->calling_len && (facil_mask & X25_MASK_CALLING_AE)) {
208                 unsigned bytecount = (dte_facs->calling_len % 2) ?
209                                         dte_facs->calling_len / 2 + 1 :
210                                         dte_facs->calling_len / 2;
211                 *p++ = X25_FAC_CALLING_AE;
212                 *p++ = 1 + bytecount;
213                 *p++ = dte_facs->calling_len;
214                 memcpy(p, dte_facs->calling_ae, bytecount);
215                 p += bytecount;
216         }
217
218         if (dte_facs->called_len && (facil_mask & X25_MASK_CALLED_AE)) {
219                 unsigned bytecount = (dte_facs->called_len % 2) ?
220                 dte_facs->called_len / 2 + 1 :
221                 dte_facs->called_len / 2;
222                 *p++ = X25_FAC_CALLED_AE;
223                 *p++ = 1 + bytecount;
224                 *p++ = dte_facs->called_len;
225                 memcpy(p, dte_facs->called_ae, bytecount);
226                 p+=bytecount;
227         }
228
229         len       = p - buffer;
230         buffer[0] = len - 1;
231
232         return len;
233 }
234
235 /*
236  *      Try to reach a compromise on a set of facilities.
237  *
238  *      The only real problem is with reverse charging.
239  */
240 int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk,
241                 struct x25_facilities *new, struct x25_dte_facilities *dte)
242 {
243         struct x25_sock *x25 = x25_sk(sk);
244         struct x25_facilities *ours = &x25->facilities;
245         struct x25_facilities theirs;
246         int len;
247
248         memset(&theirs, 0, sizeof(theirs));
249         memcpy(new, ours, sizeof(*new));
250
251         len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
252
253         /*
254          *      They want reverse charging, we won't accept it.
255          */
256         if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) {
257                 SOCK_DEBUG(sk, "X.25: rejecting reverse charging request\n");
258                 return -1;
259         }
260
261         new->reverse = theirs.reverse;
262
263         if (theirs.throughput) {
264                 if (theirs.throughput < ours->throughput) {
265                         SOCK_DEBUG(sk, "X.25: throughput negotiated down\n");
266                         new->throughput = theirs.throughput;
267                 }
268         }
269
270         if (theirs.pacsize_in && theirs.pacsize_out) {
271                 if (theirs.pacsize_in < ours->pacsize_in) {
272                         SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down\n");
273                         new->pacsize_in = theirs.pacsize_in;
274                 }
275                 if (theirs.pacsize_out < ours->pacsize_out) {
276                         SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down\n");
277                         new->pacsize_out = theirs.pacsize_out;
278                 }
279         }
280
281         if (theirs.winsize_in && theirs.winsize_out) {
282                 if (theirs.winsize_in < ours->winsize_in) {
283                         SOCK_DEBUG(sk, "X.25: window size inwards negotiated down\n");
284                         new->winsize_in = theirs.winsize_in;
285                 }
286                 if (theirs.winsize_out < ours->winsize_out) {
287                         SOCK_DEBUG(sk, "X.25: window size outwards negotiated down\n");
288                         new->winsize_out = theirs.winsize_out;
289                 }
290         }
291
292         return len;
293 }
294
295 /*
296  *      Limit values of certain facilities according to the capability of the
297  *      currently attached x25 link.
298  */
299 void x25_limit_facilities(struct x25_facilities *facilities,
300                           struct x25_neigh *nb)
301 {
302
303         if (!nb->extended) {
304                 if (facilities->winsize_in  > 7) {
305                         printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n");
306                         facilities->winsize_in = 7;
307                 }
308                 if (facilities->winsize_out > 7) {
309                         facilities->winsize_out = 7;
310                         printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n");
311                 }
312         }
313 }