2 * llc_pdu.c - access to PDU internals
4 * Copyright (c) 1997 by Procom Technology, Inc.
5 * 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
7 * This program can be redistributed or modified under the terms of the
8 * GNU General Public License as published by the Free Software Foundation.
9 * This program is distributed without any warranty or implied warranty
10 * of merchantability or fitness for a particular purpose.
12 * See the GNU General Public License for more details.
15 #include <linux/netdevice.h>
16 #include <net/llc_pdu.h>
18 static void llc_pdu_decode_pdu_type(struct sk_buff
*skb
, u8
*type
);
19 static u8
llc_pdu_get_pf_bit(struct llc_pdu_sn
*pdu
);
21 void llc_pdu_set_cmd_rsp(struct sk_buff
*skb
, u8 pdu_type
)
23 llc_pdu_un_hdr(skb
)->ssap
|= pdu_type
;
27 * pdu_set_pf_bit - sets poll/final bit in LLC header
28 * @pdu_frame: input frame that p/f bit must be set into it.
29 * @bit_value: poll/final bit (0 or 1).
31 * This function sets poll/final bit in LLC header (based on type of PDU).
32 * in I or S pdus, p/f bit is right bit of fourth byte in header. in U
33 * pdus p/f bit is fifth bit of third byte.
35 void llc_pdu_set_pf_bit(struct sk_buff
*skb
, u8 bit_value
)
38 struct llc_pdu_sn
*pdu
;
40 llc_pdu_decode_pdu_type(skb
, &pdu_type
);
41 pdu
= llc_pdu_sn_hdr(skb
);
46 pdu
->ctrl_2
= (pdu
->ctrl_2
& 0xFE) | bit_value
;
49 pdu
->ctrl_1
|= (pdu
->ctrl_1
& 0xEF) | (bit_value
<< 4);
55 * llc_pdu_decode_pf_bit - extracs poll/final bit from LLC header
56 * @skb: input skb that p/f bit must be extracted from it
57 * @pf_bit: poll/final bit (0 or 1)
59 * This function extracts poll/final bit from LLC header (based on type of
60 * PDU). In I or S pdus, p/f bit is right bit of fourth byte in header. In
61 * U pdus p/f bit is fifth bit of third byte.
63 void llc_pdu_decode_pf_bit(struct sk_buff
*skb
, u8
*pf_bit
)
66 struct llc_pdu_sn
*pdu
;
68 llc_pdu_decode_pdu_type(skb
, &pdu_type
);
69 pdu
= llc_pdu_sn_hdr(skb
);
74 *pf_bit
= pdu
->ctrl_2
& LLC_S_PF_BIT_MASK
;
77 *pf_bit
= (pdu
->ctrl_1
& LLC_U_PF_BIT_MASK
) >> 4;
83 * llc_pdu_init_as_disc_cmd - Builds DISC PDU
84 * @skb: Address of the skb to build
85 * @p_bit: The P bit to set in the PDU
87 * Builds a pdu frame as a DISC command.
89 void llc_pdu_init_as_disc_cmd(struct sk_buff
*skb
, u8 p_bit
)
91 struct llc_pdu_un
*pdu
= llc_pdu_un_hdr(skb
);
93 pdu
->ctrl_1
= LLC_PDU_TYPE_U
;
94 pdu
->ctrl_1
|= LLC_2_PDU_CMD_DISC
;
95 pdu
->ctrl_1
|= ((p_bit
& 1) << 4) & LLC_U_PF_BIT_MASK
;
99 * llc_pdu_init_as_i_cmd - builds I pdu
100 * @skb: Address of the skb to build
101 * @p_bit: The P bit to set in the PDU
102 * @ns: The sequence number of the data PDU
103 * @nr: The seq. number of the expected I PDU from the remote
105 * Builds a pdu frame as an I command.
107 void llc_pdu_init_as_i_cmd(struct sk_buff
*skb
, u8 p_bit
, u8 ns
, u8 nr
)
109 struct llc_pdu_sn
*pdu
= llc_pdu_sn_hdr(skb
);
111 pdu
->ctrl_1
= LLC_PDU_TYPE_I
;
113 pdu
->ctrl_2
|= (p_bit
& LLC_I_PF_BIT_MASK
); /* p/f bit */
114 pdu
->ctrl_1
|= (ns
<< 1) & 0xFE; /* set N(S) in bits 2..8 */
115 pdu
->ctrl_2
|= (nr
<< 1) & 0xFE; /* set N(R) in bits 10..16 */
119 * llc_pdu_init_as_rej_cmd - builds REJ PDU
120 * @skb: Address of the skb to build
121 * @p_bit: The P bit to set in the PDU
122 * @nr: The seq. number of the expected I PDU from the remote
124 * Builds a pdu frame as a REJ command.
126 void llc_pdu_init_as_rej_cmd(struct sk_buff
*skb
, u8 p_bit
, u8 nr
)
128 struct llc_pdu_sn
*pdu
= llc_pdu_sn_hdr(skb
);
130 pdu
->ctrl_1
= LLC_PDU_TYPE_S
;
131 pdu
->ctrl_1
|= LLC_2_PDU_CMD_REJ
;
133 pdu
->ctrl_2
|= p_bit
& LLC_S_PF_BIT_MASK
;
134 pdu
->ctrl_1
&= 0x0F; /* setting bits 5..8 to zero(reserved) */
135 pdu
->ctrl_2
|= (nr
<< 1) & 0xFE; /* set N(R) in bits 10..16 */
139 * llc_pdu_init_as_rnr_cmd - builds RNR pdu
140 * @skb: Address of the skb to build
141 * @p_bit: The P bit to set in the PDU
142 * @nr: The seq. number of the expected I PDU from the remote
144 * Builds a pdu frame as an RNR command.
146 void llc_pdu_init_as_rnr_cmd(struct sk_buff
*skb
, u8 p_bit
, u8 nr
)
148 struct llc_pdu_sn
*pdu
= llc_pdu_sn_hdr(skb
);
150 pdu
->ctrl_1
= LLC_PDU_TYPE_S
;
151 pdu
->ctrl_1
|= LLC_2_PDU_CMD_RNR
;
153 pdu
->ctrl_2
|= p_bit
& LLC_S_PF_BIT_MASK
;
154 pdu
->ctrl_1
&= 0x0F; /* setting bits 5..8 to zero(reserved) */
155 pdu
->ctrl_2
|= (nr
<< 1) & 0xFE; /* set N(R) in bits 10..16 */
159 * llc_pdu_init_as_rr_cmd - Builds RR pdu
160 * @skb: Address of the skb to build
161 * @p_bit: The P bit to set in the PDU
162 * @nr: The seq. number of the expected I PDU from the remote
164 * Builds a pdu frame as an RR command.
166 void llc_pdu_init_as_rr_cmd(struct sk_buff
*skb
, u8 p_bit
, u8 nr
)
168 struct llc_pdu_sn
*pdu
= llc_pdu_sn_hdr(skb
);
170 pdu
->ctrl_1
= LLC_PDU_TYPE_S
;
171 pdu
->ctrl_1
|= LLC_2_PDU_CMD_RR
;
172 pdu
->ctrl_2
= p_bit
& LLC_S_PF_BIT_MASK
;
173 pdu
->ctrl_1
&= 0x0F; /* setting bits 5..8 to zero(reserved) */
174 pdu
->ctrl_2
|= (nr
<< 1) & 0xFE; /* set N(R) in bits 10..16 */
178 * llc_pdu_init_as_sabme_cmd - builds SABME pdu
179 * @skb: Address of the skb to build
180 * @p_bit: The P bit to set in the PDU
182 * Builds a pdu frame as an SABME command.
184 void llc_pdu_init_as_sabme_cmd(struct sk_buff
*skb
, u8 p_bit
)
186 struct llc_pdu_un
*pdu
= llc_pdu_un_hdr(skb
);
188 pdu
->ctrl_1
= LLC_PDU_TYPE_U
;
189 pdu
->ctrl_1
|= LLC_2_PDU_CMD_SABME
;
190 pdu
->ctrl_1
|= ((p_bit
& 1) << 4) & LLC_U_PF_BIT_MASK
;
194 * llc_pdu_init_as_dm_rsp - builds DM response pdu
195 * @skb: Address of the skb to build
196 * @f_bit: The F bit to set in the PDU
198 * Builds a pdu frame as a DM response.
200 void llc_pdu_init_as_dm_rsp(struct sk_buff
*skb
, u8 f_bit
)
202 struct llc_pdu_un
*pdu
= llc_pdu_un_hdr(skb
);
204 pdu
->ctrl_1
= LLC_PDU_TYPE_U
;
205 pdu
->ctrl_1
|= LLC_2_PDU_RSP_DM
;
206 pdu
->ctrl_1
|= ((f_bit
& 1) << 4) & LLC_U_PF_BIT_MASK
;
210 * llc_pdu_init_as_frmr_rsp - builds FRMR response PDU
211 * @skb: Address of the frame to build
212 * @prev_pdu: The rejected PDU frame
213 * @f_bit: The F bit to set in the PDU
214 * @vs: tx state vari value for the data link conn at the rejecting LLC
215 * @vr: rx state var value for the data link conn at the rejecting LLC
216 * @vzyxw: completely described in the IEEE Std 802.2 document (Pg 55)
218 * Builds a pdu frame as a FRMR response.
220 void llc_pdu_init_as_frmr_rsp(struct sk_buff
*skb
, struct llc_pdu_sn
*prev_pdu
,
221 u8 f_bit
, u8 vs
, u8 vr
, u8 vzyxw
)
223 struct llc_frmr_info
*frmr_info
;
226 struct llc_pdu_sn
*pdu
= llc_pdu_sn_hdr(skb
);
228 pdu
->ctrl_1
= LLC_PDU_TYPE_U
;
229 pdu
->ctrl_1
|= LLC_2_PDU_RSP_FRMR
;
230 pdu
->ctrl_1
|= ((f_bit
& 1) << 4) & LLC_U_PF_BIT_MASK
;
232 frmr_info
= (struct llc_frmr_info
*)&pdu
->ctrl_2
;
233 ctrl
= (u8
*)&prev_pdu
->ctrl_1
;
234 FRMR_INFO_SET_REJ_CNTRL(frmr_info
,ctrl
);
235 FRMR_INFO_SET_Vs(frmr_info
, vs
);
236 FRMR_INFO_SET_Vr(frmr_info
, vr
);
237 prev_pf
= llc_pdu_get_pf_bit(prev_pdu
);
238 FRMR_INFO_SET_C_R_BIT(frmr_info
, prev_pf
);
239 FRMR_INFO_SET_INVALID_PDU_CTRL_IND(frmr_info
, vzyxw
);
240 FRMR_INFO_SET_INVALID_PDU_INFO_IND(frmr_info
, vzyxw
);
241 FRMR_INFO_SET_PDU_INFO_2LONG_IND(frmr_info
, vzyxw
);
242 FRMR_INFO_SET_PDU_INVALID_Nr_IND(frmr_info
, vzyxw
);
243 FRMR_INFO_SET_PDU_INVALID_Ns_IND(frmr_info
, vzyxw
);
248 * llc_pdu_init_as_rr_rsp - builds RR response pdu
249 * @skb: Address of the skb to build
250 * @f_bit: The F bit to set in the PDU
251 * @nr: The seq. number of the expected data PDU from the remote
253 * Builds a pdu frame as an RR response.
255 void llc_pdu_init_as_rr_rsp(struct sk_buff
*skb
, u8 f_bit
, u8 nr
)
257 struct llc_pdu_sn
*pdu
= llc_pdu_sn_hdr(skb
);
259 pdu
->ctrl_1
= LLC_PDU_TYPE_S
;
260 pdu
->ctrl_1
|= LLC_2_PDU_RSP_RR
;
262 pdu
->ctrl_2
|= f_bit
& LLC_S_PF_BIT_MASK
;
263 pdu
->ctrl_1
&= 0x0F; /* setting bits 5..8 to zero(reserved) */
264 pdu
->ctrl_2
|= (nr
<< 1) & 0xFE; /* set N(R) in bits 10..16 */
268 * llc_pdu_init_as_rej_rsp - builds REJ response pdu
269 * @skb: Address of the skb to build
270 * @f_bit: The F bit to set in the PDU
271 * @nr: The seq. number of the expected data PDU from the remote
273 * Builds a pdu frame as a REJ response.
275 void llc_pdu_init_as_rej_rsp(struct sk_buff
*skb
, u8 f_bit
, u8 nr
)
277 struct llc_pdu_sn
*pdu
= llc_pdu_sn_hdr(skb
);
279 pdu
->ctrl_1
= LLC_PDU_TYPE_S
;
280 pdu
->ctrl_1
|= LLC_2_PDU_RSP_REJ
;
282 pdu
->ctrl_2
|= f_bit
& LLC_S_PF_BIT_MASK
;
283 pdu
->ctrl_1
&= 0x0F; /* setting bits 5..8 to zero(reserved) */
284 pdu
->ctrl_2
|= (nr
<< 1) & 0xFE; /* set N(R) in bits 10..16 */
288 * llc_pdu_init_as_rnr_rsp - builds RNR response pdu
289 * @skb: Address of the frame to build
290 * @f_bit: The F bit to set in the PDU
291 * @nr: The seq. number of the expected data PDU from the remote
293 * Builds a pdu frame as an RNR response.
295 void llc_pdu_init_as_rnr_rsp(struct sk_buff
*skb
, u8 f_bit
, u8 nr
)
297 struct llc_pdu_sn
*pdu
= llc_pdu_sn_hdr(skb
);
299 pdu
->ctrl_1
= LLC_PDU_TYPE_S
;
300 pdu
->ctrl_1
|= LLC_2_PDU_RSP_RNR
;
302 pdu
->ctrl_2
|= f_bit
& LLC_S_PF_BIT_MASK
;
303 pdu
->ctrl_1
&= 0x0F; /* setting bits 5..8 to zero(reserved) */
304 pdu
->ctrl_2
|= (nr
<< 1) & 0xFE; /* set N(R) in bits 10..16 */
308 * llc_pdu_init_as_ua_rsp - builds UA response pdu
309 * @skb: Address of the frame to build
310 * @f_bit: The F bit to set in the PDU
312 * Builds a pdu frame as a UA response.
314 void llc_pdu_init_as_ua_rsp(struct sk_buff
*skb
, u8 f_bit
)
316 struct llc_pdu_un
*pdu
= llc_pdu_un_hdr(skb
);
318 pdu
->ctrl_1
= LLC_PDU_TYPE_U
;
319 pdu
->ctrl_1
|= LLC_2_PDU_RSP_UA
;
320 pdu
->ctrl_1
|= ((f_bit
& 1) << 4) & LLC_U_PF_BIT_MASK
;
324 * llc_pdu_decode_pdu_type - designates PDU type
325 * @skb: input skb that type of it must be designated.
326 * @type: type of PDU (output argument).
328 * This function designates type of PDU (I, S or U).
330 static void llc_pdu_decode_pdu_type(struct sk_buff
*skb
, u8
*type
)
332 struct llc_pdu_un
*pdu
= llc_pdu_un_hdr(skb
);
334 if (pdu
->ctrl_1
& 1) {
335 if ((pdu
->ctrl_1
& LLC_PDU_TYPE_U
) == LLC_PDU_TYPE_U
)
336 *type
= LLC_PDU_TYPE_U
;
338 *type
= LLC_PDU_TYPE_S
;
340 *type
= LLC_PDU_TYPE_I
;
344 * llc_pdu_get_pf_bit - extracts p/f bit of input PDU
345 * @pdu: pointer to LLC header.
347 * This function extracts p/f bit of input PDU. at first examines type of
348 * PDU and then extracts p/f bit. Returns the p/f bit.
350 static u8
llc_pdu_get_pf_bit(struct llc_pdu_sn
*pdu
)
355 if (pdu
->ctrl_1
& 1) {
356 if ((pdu
->ctrl_1
& LLC_PDU_TYPE_U
) == LLC_PDU_TYPE_U
)
357 pdu_type
= LLC_PDU_TYPE_U
;
359 pdu_type
= LLC_PDU_TYPE_S
;
361 pdu_type
= LLC_PDU_TYPE_I
;
365 pf_bit
= pdu
->ctrl_2
& LLC_S_PF_BIT_MASK
;
368 pf_bit
= (pdu
->ctrl_1
& LLC_U_PF_BIT_MASK
) >> 4;
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