Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
[~shefty/rdma-dev.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;
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         if (skb->len < 1)
54                 return 0;
55
56         len = *p++;
57
58         if (len >= skb->len)
59                 return -1;
60
61         while (len > 0) {
62                 switch (*p & X25_FAC_CLASS_MASK) {
63                 case X25_FAC_CLASS_A:
64                         if (len < 2)
65                                 return 0;
66                         switch (*p) {
67                         case X25_FAC_REVERSE:
68                                 if((p[1] & 0x81) == 0x81) {
69                                         facilities->reverse = p[1] & 0x81;
70                                         *vc_fac_mask |= X25_MASK_REVERSE;
71                                         break;
72                                 }
73
74                                 if((p[1] & 0x01) == 0x01) {
75                                         facilities->reverse = p[1] & 0x01;
76                                         *vc_fac_mask |= X25_MASK_REVERSE;
77                                         break;
78                                 }
79
80                                 if((p[1] & 0x80) == 0x80) {
81                                         facilities->reverse = p[1] & 0x80;
82                                         *vc_fac_mask |= X25_MASK_REVERSE;
83                                         break;
84                                 }
85
86                                 if(p[1] == 0x00) {
87                                         facilities->reverse
88                                                 = X25_DEFAULT_REVERSE;
89                                         *vc_fac_mask |= X25_MASK_REVERSE;
90                                         break;
91                                 }
92
93                         case X25_FAC_THROUGHPUT:
94                                 facilities->throughput = p[1];
95                                 *vc_fac_mask |= X25_MASK_THROUGHPUT;
96                                 break;
97                         case X25_MARKER:
98                                 break;
99                         default:
100                                 printk(KERN_DEBUG "X.25: unknown facility "
101                                        "%02X, value %02X\n",
102                                        p[0], p[1]);
103                                 break;
104                         }
105                         p   += 2;
106                         len -= 2;
107                         break;
108                 case X25_FAC_CLASS_B:
109                         if (len < 3)
110                                 return 0;
111                         switch (*p) {
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;
116                                 break;
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;
121                                 break;
122                         default:
123                                 printk(KERN_DEBUG "X.25: unknown facility "
124                                        "%02X, values %02X, %02X\n",
125                                        p[0], p[1], p[2]);
126                                 break;
127                         }
128                         p   += 3;
129                         len -= 3;
130                         break;
131                 case X25_FAC_CLASS_C:
132                         if (len < 4)
133                                 return 0;
134                         printk(KERN_DEBUG "X.25: unknown facility %02X, "
135                                "values %02X, %02X, %02X\n",
136                                p[0], p[1], p[2], p[3]);
137                         p   += 4;
138                         len -= 4;
139                         break;
140                 case X25_FAC_CLASS_D:
141                         if (len < p[1] + 2)
142                                 return 0;
143                         switch (*p) {
144                         case X25_FAC_CALLING_AE:
145                                 if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
146                                         return 0;
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;
150                                 break;
151                         case X25_FAC_CALLED_AE:
152                                 if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
153                                         return 0;
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;
157                                 break;
158                         default:
159                                 printk(KERN_DEBUG "X.25: unknown facility %02X,"
160                                         "length %d\n", p[0], p[1]);
161                                 break;
162                         }
163                         len -= p[1] + 2;
164                         p += p[1] + 2;
165                         break;
166                 }
167         }
168
169         return p - skb->data;
170 }
171
172 /*
173  *      Create a set of facilities.
174  */
175 int x25_create_facilities(unsigned char *buffer,
176                 struct x25_facilities *facilities,
177                 struct x25_dte_facilities *dte_facs, unsigned long facil_mask)
178 {
179         unsigned char *p = buffer + 1;
180         int len;
181
182         if (!facil_mask) {
183                 /*
184                  * Length of the facilities field in call_req or
185                  * call_accept packets
186                  */
187                 buffer[0] = 0;
188                 len = 1; /* 1 byte for the length field */
189                 return len;
190         }
191
192         if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) {
193                 *p++ = X25_FAC_REVERSE;
194                 *p++ = facilities->reverse;
195         }
196
197         if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) {
198                 *p++ = X25_FAC_THROUGHPUT;
199                 *p++ = facilities->throughput;
200         }
201
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;
207         }
208
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;
214         }
215
216         if (facil_mask & (X25_MASK_CALLING_AE|X25_MASK_CALLED_AE)) {
217                 *p++ = X25_MARKER;
218                 *p++ = X25_DTE_SERVICES;
219         }
220
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);
227                 p += bytecount;
228         }
229
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);
238                 p+=bytecount;
239         }
240
241         len       = p - buffer;
242         buffer[0] = len - 1;
243
244         return len;
245 }
246
247 /*
248  *      Try to reach a compromise on a set of facilities.
249  *
250  *      The only real problem is with reverse charging.
251  */
252 int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk,
253                 struct x25_facilities *new, struct x25_dte_facilities *dte)
254 {
255         struct x25_sock *x25 = x25_sk(sk);
256         struct x25_facilities *ours = &x25->facilities;
257         struct x25_facilities theirs;
258         int len;
259
260         memset(&theirs, 0, sizeof(theirs));
261         memcpy(new, ours, sizeof(*new));
262
263         len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
264         if (len < 0)
265                 return len;
266
267         /*
268          *      They want reverse charging, we won't accept it.
269          */
270         if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) {
271                 SOCK_DEBUG(sk, "X.25: rejecting reverse charging request\n");
272                 return -1;
273         }
274
275         new->reverse = theirs.reverse;
276
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;
285                 }
286                 if (!ours_out || theirs_out < ours_out) {
287                         SOCK_DEBUG(sk,
288                                 "X.25: outbound throughput negotiated\n");
289                         new->throughput = (new->throughput & 0x0f) | theirs_out;
290                 }
291         }
292
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;
297                 }
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;
301                 }
302         }
303
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;
308                 }
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;
312                 }
313         }
314
315         return len;
316 }
317
318 /*
319  *      Limit values of certain facilities according to the capability of the
320  *      currently attached x25 link.
321  */
322 void x25_limit_facilities(struct x25_facilities *facilities,
323                           struct x25_neigh *nb)
324 {
325
326         if (!nb->extended) {
327                 if (facilities->winsize_in  > 7) {
328                         printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n");
329                         facilities->winsize_in = 7;
330                 }
331                 if (facilities->winsize_out > 7) {
332                         facilities->winsize_out = 7;
333                         printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n");
334                 }
335         }
336 }