1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
|
/*
* llc_pdu.c - access to PDU internals
*
* Copyright (c) 1997 by Procom Technology, Inc.
* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program can be redistributed or modified under the terms of the
* GNU General Public License as published by the Free Software Foundation.
* This program is distributed without any warranty or implied warranty
* of merchantability or fitness for a particular purpose.
*
* See the GNU General Public License for more details.
*/
#include <linux/netdevice.h>
#include <net/llc_pdu.h>
static void llc_pdu_decode_pdu_type(struct sk_buff *skb, u8 *type);
static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu);
void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 pdu_type)
{
llc_pdu_un_hdr(skb)->ssap |= pdu_type;
}
/**
* llc_pdu_set_pf_bit - sets poll/final bit in LLC header
* @skb: Frame to set bit in
* @bit_value: poll/final bit (0 or 1).
*
* This function sets poll/final bit in LLC header (based on type of PDU).
* in I or S pdus, p/f bit is right bit of fourth byte in header. in U
* pdus p/f bit is fifth bit of third byte.
*/
void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value)
{
u8 pdu_type;
struct llc_pdu_sn *pdu;
llc_pdu_decode_pdu_type(skb, &pdu_type);
pdu = llc_pdu_sn_hdr(skb);
switch (pdu_type) {
case LLC_PDU_TYPE_I:
case LLC_PDU_TYPE_S:
pdu->ctrl_2 = (pdu->ctrl_2 & 0xFE) | bit_value;
break;
case LLC_PDU_TYPE_U:
pdu->ctrl_1 |= (pdu->ctrl_1 & 0xEF) | (bit_value << 4);
break;
}
}
/**
* llc_pdu_decode_pf_bit - extracs poll/final bit from LLC header
* @skb: input skb that p/f bit must be extracted from it
* @pf_bit: poll/final bit (0 or 1)
*
* This function extracts poll/final bit from LLC header (based on type of
* PDU). In I or S pdus, p/f bit is right bit of fourth byte in header. In
* U pdus p/f bit is fifth bit of third byte.
*/
void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit)
{
u8 pdu_type;
struct llc_pdu_sn *pdu;
llc_pdu_decode_pdu_type(skb, &pdu_type);
pdu = llc_pdu_sn_hdr(skb);
switch (pdu_type) {
case LLC_PDU_TYPE_I:
case LLC_PDU_TYPE_S:
*pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK;
break;
case LLC_PDU_TYPE_U:
*pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4;
break;
}
}
/**
* llc_pdu_init_as_disc_cmd - Builds DISC PDU
* @skb: Address of the skb to build
* @p_bit: The P bit to set in the PDU
*
* Builds a pdu frame as a DISC command.
*/
void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit)
{
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_U;
pdu->ctrl_1 |= LLC_2_PDU_CMD_DISC;
pdu->ctrl_1 |= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
}
/**
* llc_pdu_init_as_i_cmd - builds I pdu
* @skb: Address of the skb to build
* @p_bit: The P bit to set in the PDU
* @ns: The sequence number of the data PDU
* @nr: The seq. number of the expected I PDU from the remote
*
* Builds a pdu frame as an I command.
*/
void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr)
{
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_I;
pdu->ctrl_2 = 0;
pdu->ctrl_2 |= (p_bit & LLC_I_PF_BIT_MASK); /* p/f bit */
pdu->ctrl_1 |= (ns << 1) & 0xFE; /* set N(S) in bits 2..8 */
pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}
/**
* llc_pdu_init_as_rej_cmd - builds REJ PDU
* @skb: Address of the skb to build
* @p_bit: The P bit to set in the PDU
* @nr: The seq. number of the expected I PDU from the remote
*
* Builds a pdu frame as a REJ command.
*/
void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
{
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_S;
pdu->ctrl_1 |= LLC_2_PDU_CMD_REJ;
pdu->ctrl_2 = 0;
pdu->ctrl_2 |= p_bit & LLC_S_PF_BIT_MASK;
pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}
/**
* llc_pdu_init_as_rnr_cmd - builds RNR pdu
* @skb: Address of the skb to build
* @p_bit: The P bit to set in the PDU
* @nr: The seq. number of the expected I PDU from the remote
*
* Builds a pdu frame as an RNR command.
*/
void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
{
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_S;
pdu->ctrl_1 |= LLC_2_PDU_CMD_RNR;
pdu->ctrl_2 = 0;
pdu->ctrl_2 |= p_bit & LLC_S_PF_BIT_MASK;
pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}
/**
* llc_pdu_init_as_rr_cmd - Builds RR pdu
* @skb: Address of the skb to build
* @p_bit: The P bit to set in the PDU
* @nr: The seq. number of the expected I PDU from the remote
*
* Builds a pdu frame as an RR command.
*/
void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
{
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_S;
pdu->ctrl_1 |= LLC_2_PDU_CMD_RR;
pdu->ctrl_2 = p_bit & LLC_S_PF_BIT_MASK;
pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}
/**
* llc_pdu_init_as_sabme_cmd - builds SABME pdu
* @skb: Address of the skb to build
* @p_bit: The P bit to set in the PDU
*
* Builds a pdu frame as an SABME command.
*/
void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit)
{
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_U;
pdu->ctrl_1 |= LLC_2_PDU_CMD_SABME;
pdu->ctrl_1 |= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
}
/**
* llc_pdu_init_as_dm_rsp - builds DM response pdu
* @skb: Address of the skb to build
* @f_bit: The F bit to set in the PDU
*
* Builds a pdu frame as a DM response.
*/
void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit)
{
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_U;
pdu->ctrl_1 |= LLC_2_PDU_RSP_DM;
pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
}
/**
* llc_pdu_init_as_frmr_rsp - builds FRMR response PDU
* @skb: Address of the frame to build
* @prev_pdu: The rejected PDU frame
* @f_bit: The F bit to set in the PDU
* @vs: tx state vari value for the data link conn at the rejecting LLC
* @vr: rx state var value for the data link conn at the rejecting LLC
* @vzyxw: completely described in the IEEE Std 802.2 document (Pg 55)
*
* Builds a pdu frame as a FRMR response.
*/
void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb, struct llc_pdu_sn *prev_pdu,
u8 f_bit, u8 vs, u8 vr, u8 vzyxw)
{
struct llc_frmr_info *frmr_info;
u8 prev_pf = 0;
u8 *ctrl;
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_U;
pdu->ctrl_1 |= LLC_2_PDU_RSP_FRMR;
pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
frmr_info = (struct llc_frmr_info *)&pdu->ctrl_2;
ctrl = (u8 *)&prev_pdu->ctrl_1;
FRMR_INFO_SET_REJ_CNTRL(frmr_info,ctrl);
FRMR_INFO_SET_Vs(frmr_info, vs);
FRMR_INFO_SET_Vr(frmr_info, vr);
prev_pf = llc_pdu_get_pf_bit(prev_pdu);
FRMR_INFO_SET_C_R_BIT(frmr_info, prev_pf);
FRMR_INFO_SET_INVALID_PDU_CTRL_IND(frmr_info, vzyxw);
FRMR_INFO_SET_INVALID_PDU_INFO_IND(frmr_info, vzyxw);
FRMR_INFO_SET_PDU_INFO_2LONG_IND(frmr_info, vzyxw);
FRMR_INFO_SET_PDU_INVALID_Nr_IND(frmr_info, vzyxw);
FRMR_INFO_SET_PDU_INVALID_Ns_IND(frmr_info, vzyxw);
skb_put(skb, sizeof(struct llc_frmr_info));
}
/**
* llc_pdu_init_as_rr_rsp - builds RR response pdu
* @skb: Address of the skb to build
* @f_bit: The F bit to set in the PDU
* @nr: The seq. number of the expected data PDU from the remote
*
* Builds a pdu frame as an RR response.
*/
void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
{
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_S;
pdu->ctrl_1 |= LLC_2_PDU_RSP_RR;
pdu->ctrl_2 = 0;
pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK;
pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}
/**
* llc_pdu_init_as_rej_rsp - builds REJ response pdu
* @skb: Address of the skb to build
* @f_bit: The F bit to set in the PDU
* @nr: The seq. number of the expected data PDU from the remote
*
* Builds a pdu frame as a REJ response.
*/
void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
{
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_S;
pdu->ctrl_1 |= LLC_2_PDU_RSP_REJ;
pdu->ctrl_2 = 0;
pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK;
pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}
/**
* llc_pdu_init_as_rnr_rsp - builds RNR response pdu
* @skb: Address of the frame to build
* @f_bit: The F bit to set in the PDU
* @nr: The seq. number of the expected data PDU from the remote
*
* Builds a pdu frame as an RNR response.
*/
void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
{
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_S;
pdu->ctrl_1 |= LLC_2_PDU_RSP_RNR;
pdu->ctrl_2 = 0;
pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK;
pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}
/**
* llc_pdu_init_as_ua_rsp - builds UA response pdu
* @skb: Address of the frame to build
* @f_bit: The F bit to set in the PDU
*
* Builds a pdu frame as a UA response.
*/
void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit)
{
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
pdu->ctrl_1 = LLC_PDU_TYPE_U;
pdu->ctrl_1 |= LLC_2_PDU_RSP_UA;
pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
}
/**
* llc_pdu_decode_pdu_type - designates PDU type
* @skb: input skb that type of it must be designated.
* @type: type of PDU (output argument).
*
* This function designates type of PDU (I, S or U).
*/
static void llc_pdu_decode_pdu_type(struct sk_buff *skb, u8 *type)
{
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
if (pdu->ctrl_1 & 1) {
if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U)
*type = LLC_PDU_TYPE_U;
else
*type = LLC_PDU_TYPE_S;
} else
*type = LLC_PDU_TYPE_I;
}
/**
* llc_pdu_get_pf_bit - extracts p/f bit of input PDU
* @pdu: pointer to LLC header.
*
* This function extracts p/f bit of input PDU. at first examines type of
* PDU and then extracts p/f bit. Returns the p/f bit.
*/
static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu)
{
u8 pdu_type;
u8 pf_bit = 0;
if (pdu->ctrl_1 & 1) {
if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U)
pdu_type = LLC_PDU_TYPE_U;
else
pdu_type = LLC_PDU_TYPE_S;
} else
pdu_type = LLC_PDU_TYPE_I;
switch (pdu_type) {
case LLC_PDU_TYPE_I:
case LLC_PDU_TYPE_S:
pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK;
break;
case LLC_PDU_TYPE_U:
pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4;
break;
}
return pf_bit;
}
|
