netfilter: xt_qtaguid: warn only once for missing proc qtaguid data
[linux-2.6.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  * x25_parse_facilities - Parse facilities from skb into the facilities structs
32  *
33  * @skb: sk_buff to parse
34  * @facilities: Regular facilities, updated as facilities are found
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  *
43  */
44 int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities,
45                 struct x25_dte_facilities *dte_facs, unsigned long *vc_fac_mask)
46 {
47         unsigned char *p;
48         unsigned int len;
49
50         *vc_fac_mask = 0;
51
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
63         if (!pskb_may_pull(skb, 1))
64                 return 0;
65
66         len = skb->data[0];
67
68         if (!pskb_may_pull(skb, 1 + len))
69                 return -1;
70
71         p = skb->data + 1;
72
73         while (len > 0) {
74                 switch (*p & X25_FAC_CLASS_MASK) {
75                 case X25_FAC_CLASS_A:
76                         if (len < 2)
77                                 return -1;
78                         switch (*p) {
79                         case X25_FAC_REVERSE:
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
105                         case X25_FAC_THROUGHPUT:
106                                 facilities->throughput = p[1];
107                                 *vc_fac_mask |= X25_MASK_THROUGHPUT;
108                                 break;
109                         case X25_MARKER:
110                                 break;
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:
121                         if (len < 3)
122                                 return -1;
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:
144                         if (len < 4)
145                                 return -1;
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:
153                         if (len < p[1] + 2)
154                                 return -1;
155                         switch (*p) {
156                         case X25_FAC_CALLING_AE:
157                                 if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
158                                         return -1;
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:
164                                 if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
165                                         return -1;
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,"
172                                         "length %d\n", p[0], p[1]);
173                                 break;
174                         }
175                         len -= p[1] + 2;
176                         p += p[1] + 2;
177                         break;
178                 }
179         }
180
181         return p - skb->data;
182 }
183
184 /*
185  *      Create a set of facilities.
186  */
187 int x25_create_facilities(unsigned char *buffer,
188                 struct x25_facilities *facilities,
189                 struct x25_dte_facilities *dte_facs, unsigned long facil_mask)
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;
206                 *p++ = facilities->reverse;
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
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)) {
234                 unsigned bytecount = (dte_facs->calling_len + 1) >> 1;
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)) {
243                 unsigned bytecount = (dte_facs->called_len % 2) ?
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
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  */
264 int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk,
265                 struct x25_facilities *new, struct x25_dte_facilities *dte)
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));
274
275         len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
276         if (len < 0)
277                 return len;
278
279         /*
280          *      They want reverse charging, we won't accept it.
281          */
282         if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) {
283                 SOCK_DEBUG(sk, "X.25: rejecting reverse charging request\n");
284                 return -1;
285         }
286
287         new->reverse = theirs.reverse;
288
289         if (theirs.throughput) {
290                 int theirs_in =  theirs.throughput & 0x0f;
291                 int theirs_out = theirs.throughput & 0xf0;
292                 int ours_in  = ours->throughput & 0x0f;
293                 int ours_out = ours->throughput & 0xf0;
294                 if (!ours_in || theirs_in < ours_in) {
295                         SOCK_DEBUG(sk, "X.25: inbound throughput negotiated\n");
296                         new->throughput = (new->throughput & 0xf0) | theirs_in;
297                 }
298                 if (!ours_out || theirs_out < ours_out) {
299                         SOCK_DEBUG(sk,
300                                 "X.25: outbound throughput negotiated\n");
301                         new->throughput = (new->throughput & 0x0f) | theirs_out;
302                 }
303         }
304
305         if (theirs.pacsize_in && theirs.pacsize_out) {
306                 if (theirs.pacsize_in < ours->pacsize_in) {
307                         SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down\n");
308                         new->pacsize_in = theirs.pacsize_in;
309                 }
310                 if (theirs.pacsize_out < ours->pacsize_out) {
311                         SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down\n");
312                         new->pacsize_out = theirs.pacsize_out;
313                 }
314         }
315
316         if (theirs.winsize_in && theirs.winsize_out) {
317                 if (theirs.winsize_in < ours->winsize_in) {
318                         SOCK_DEBUG(sk, "X.25: window size inwards negotiated down\n");
319                         new->winsize_in = theirs.winsize_in;
320                 }
321                 if (theirs.winsize_out < ours->winsize_out) {
322                         SOCK_DEBUG(sk, "X.25: window size outwards negotiated down\n");
323                         new->winsize_out = theirs.winsize_out;
324                 }
325         }
326
327         return len;
328 }
329
330 /*
331  *      Limit values of certain facilities according to the capability of the
332  *      currently attached x25 link.
333  */
334 void x25_limit_facilities(struct x25_facilities *facilities,
335                           struct x25_neigh *nb)
336 {
337
338         if (!nb->extended) {
339                 if (facilities->winsize_in  > 7) {
340                         printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n");
341                         facilities->winsize_in = 7;
342                 }
343                 if (facilities->winsize_out > 7) {
344                         facilities->winsize_out = 7;
345                         printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n");
346                 }
347         }
348 }