1 #ifndef LLC_PDU_H
2 #define LLC_PDU_H
3 /*
4 * Copyright (c) 1997 by Procom Technology,Inc.
5 * 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 *
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.
11 *
12 * See the GNU General Public License for more details.
13 */
14
15 #include <linux/if_ether.h>
16
17 /* Lengths of frame formats */
18 #define LLC_PDU_LEN_I 4 /* header and 2 control bytes */
19 #define LLC_PDU_LEN_S 4
20 #define LLC_PDU_LEN_U 3 /* header and 1 control byte */
21 /* header and 1 control byte and XID info */
22 #define LLC_PDU_LEN_U_XID (LLC_PDU_LEN_U + sizeof(struct llc_xid_info))
23 /* Known SAP addresses */
24 #define LLC_GLOBAL_SAP 0xFF
25 #define LLC_NULL_SAP 0x00 /* not network-layer visible */
26 #define LLC_MGMT_INDIV 0x02 /* station LLC mgmt indiv addr */
27 #define LLC_MGMT_GRP 0x03 /* station LLC mgmt group addr */
28 #define LLC_RDE_SAP 0xA6 /* route ... */
29
30 /* SAP field bit masks */
31 #define LLC_ISO_RESERVED_SAP 0x02
32 #define LLC_SAP_GROUP_DSAP 0x01
33 #define LLC_SAP_RESP_SSAP 0x01
34
35 /* Group/individual DSAP indicator is DSAP field */
36 #define LLC_PDU_GROUP_DSAP_MASK 0x01
37 #define LLC_PDU_IS_GROUP_DSAP(pdu) \
38 ((pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
39 #define LLC_PDU_IS_INDIV_DSAP(pdu) \
40 (!(pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
41
42 /* Command/response PDU indicator in SSAP field */
43 #define LLC_PDU_CMD_RSP_MASK 0x01
44 #define LLC_PDU_CMD 0
45 #define LLC_PDU_RSP 1
46 #define LLC_PDU_IS_CMD(pdu) ((pdu->ssap & LLC_PDU_RSP) ? 0 : 1)
47 #define LLC_PDU_IS_RSP(pdu) ((pdu->ssap & LLC_PDU_RSP) ? 1 : 0)
48
49 /* Get PDU type from 2 lowest-order bits of control field first byte */
50 #define LLC_PDU_TYPE_I_MASK 0x01 /* 16-bit control field */
51 #define LLC_PDU_TYPE_S_MASK 0x03
52 #define LLC_PDU_TYPE_U_MASK 0x03 /* 8-bit control field */
53 #define LLC_PDU_TYPE_MASK 0x03
54
55 #define LLC_PDU_TYPE_I 0 /* first bit */
56 #define LLC_PDU_TYPE_S 1 /* first two bits */
57 #define LLC_PDU_TYPE_U 3 /* first two bits */
58 #define LLC_PDU_TYPE_U_XID 4 /* private type for detecting XID commands */
59
60 #define LLC_PDU_TYPE_IS_I(pdu) \
61 ((!(pdu->ctrl_1 & LLC_PDU_TYPE_I_MASK)) ? 1 : 0)
62
63 #define LLC_PDU_TYPE_IS_U(pdu) \
64 (((pdu->ctrl_1 & LLC_PDU_TYPE_U_MASK) == LLC_PDU_TYPE_U) ? 1 : 0)
65
66 #define LLC_PDU_TYPE_IS_S(pdu) \
67 (((pdu->ctrl_1 & LLC_PDU_TYPE_S_MASK) == LLC_PDU_TYPE_S) ? 1 : 0)
68
69 /* U-format PDU control field masks */
70 #define LLC_U_PF_BIT_MASK 0x10 /* P/F bit mask */
71 #define LLC_U_PF_IS_1(pdu) ((pdu->ctrl_1 & LLC_U_PF_BIT_MASK) ? 1 : 0)
72 #define LLC_U_PF_IS_0(pdu) ((!(pdu->ctrl_1 & LLC_U_PF_BIT_MASK)) ? 1 : 0)
73
74 #define LLC_U_PDU_CMD_MASK 0xEC /* cmd/rsp mask */
75 #define LLC_U_PDU_CMD(pdu) (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
76 #define LLC_U_PDU_RSP(pdu) (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
77
78 #define LLC_1_PDU_CMD_UI 0x00 /* Type 1 cmds/rsps */
79 #define LLC_1_PDU_CMD_XID 0xAC
80 #define LLC_1_PDU_CMD_TEST 0xE0
81
82 #define LLC_2_PDU_CMD_SABME 0x6C /* Type 2 cmds/rsps */
83 #define LLC_2_PDU_CMD_DISC 0x40
84 #define LLC_2_PDU_RSP_UA 0x60
85 #define LLC_2_PDU_RSP_DM 0x0C
86 #define LLC_2_PDU_RSP_FRMR 0x84
87
88 /* Type 1 operations */
89
90 /* XID information field bit masks */
91
92 /* LLC format identifier (byte 1) */
93 #define LLC_XID_FMT_ID 0x81 /* first byte must be this */
94
95 /* LLC types/classes identifier (byte 2) */
96 #define LLC_XID_CLASS_ZEROS_MASK 0xE0 /* these must be zeros */
97 #define LLC_XID_CLASS_MASK 0x1F /* AND with byte to get below */
98
99 #define LLC_XID_NULL_CLASS_1 0x01 /* if NULL LSAP...use these */
100 #define LLC_XID_NULL_CLASS_2 0x03
101 #define LLC_XID_NULL_CLASS_3 0x05
102 #define LLC_XID_NULL_CLASS_4 0x07
103
104 #define LLC_XID_NNULL_TYPE_1 0x01 /* if non-NULL LSAP...use these */
105 #define LLC_XID_NNULL_TYPE_2 0x02
106 #define LLC_XID_NNULL_TYPE_3 0x04
107 #define LLC_XID_NNULL_TYPE_1_2 0x03
108 #define LLC_XID_NNULL_TYPE_1_3 0x05
109 #define LLC_XID_NNULL_TYPE_2_3 0x06
110 #define LLC_XID_NNULL_ALL 0x07
111
112 /* Sender Receive Window (byte 3) */
113 #define LLC_XID_RW_MASK 0xFE /* AND with value to get below */
114
115 #define LLC_XID_MIN_RW 0x02 /* lowest-order bit always zero */
116
117 /* Type 2 operations */
118
119 #define LLC_2_SEQ_NBR_MODULO ((u8) 128)
120
121 /* I-PDU masks ('ctrl' is I-PDU control word) */
122 #define LLC_I_GET_NS(pdu) (u8)((pdu->ctrl_1 & 0xFE) >> 1)
123 #define LLC_I_GET_NR(pdu) (u8)((pdu->ctrl_2 & 0xFE) >> 1)
124
125 #define LLC_I_PF_BIT_MASK 0x01
126
127 #define LLC_I_PF_IS_0(pdu) ((!(pdu->ctrl_2 & LLC_I_PF_BIT_MASK)) ? 1 : 0)
128 #define LLC_I_PF_IS_1(pdu) ((pdu->ctrl_2 & LLC_I_PF_BIT_MASK) ? 1 : 0)
129
130 /* S-PDU supervisory commands and responses */
131
132 #define LLC_S_PDU_CMD_MASK 0x0C
133 #define LLC_S_PDU_CMD(pdu) (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
134 #define LLC_S_PDU_RSP(pdu) (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
135
136 #define LLC_2_PDU_CMD_RR 0x00 /* rx ready cmd */
137 #define LLC_2_PDU_RSP_RR 0x00 /* rx ready rsp */
138 #define LLC_2_PDU_CMD_REJ 0x08 /* reject PDU cmd */
139 #define LLC_2_PDU_RSP_REJ 0x08 /* reject PDU rsp */
140 #define LLC_2_PDU_CMD_RNR 0x04 /* rx not ready cmd */
141 #define LLC_2_PDU_RSP_RNR 0x04 /* rx not ready rsp */
142
143 #define LLC_S_PF_BIT_MASK 0x01
144 #define LLC_S_PF_IS_0(pdu) ((!(pdu->ctrl_2 & LLC_S_PF_BIT_MASK)) ? 1 : 0)
145 #define LLC_S_PF_IS_1(pdu) ((pdu->ctrl_2 & LLC_S_PF_BIT_MASK) ? 1 : 0)
146
147 #define PDU_SUPV_GET_Nr(pdu) ((pdu->ctrl_2 & 0xFE) >> 1)
148 #define PDU_GET_NEXT_Vr(sn) (((sn) + 1) & ~LLC_2_SEQ_NBR_MODULO)
149
150 /* FRMR information field macros */
151
152 #define FRMR_INFO_LENGTH 5 /* 5 bytes of information */
153
154 /*
155 * info is pointer to FRMR info field structure; 'rej_ctrl' is byte pointer
156 * (if U-PDU) or word pointer to rejected PDU control field
157 */
158 #define FRMR_INFO_SET_REJ_CNTRL(info,rej_ctrl) \
159 info->rej_pdu_ctrl = ((*((u8 *) rej_ctrl) & \
160 LLC_PDU_TYPE_U) != LLC_PDU_TYPE_U ? \
161 (u16)*((u16 *) rej_ctrl) : \
162 (((u16) *((u8 *) rej_ctrl)) & 0x00FF))
163
164 /*
165 * Info is pointer to FRMR info field structure; 'vs' is a byte containing
166 * send state variable value in low-order 7 bits (insure the lowest-order
167 * bit remains zero (0))
168 */
169 #define FRMR_INFO_SET_Vs(info,vs) (info->curr_ssv = (((u8) vs) << 1))
170 #define FRMR_INFO_SET_Vr(info,vr) (info->curr_rsv = (((u8) vr) << 1))
171
172 /*
173 * Info is pointer to FRMR info field structure; 'cr' is a byte containing
174 * the C/R bit value in the low-order bit
175 */
176 #define FRMR_INFO_SET_C_R_BIT(info, cr) (info->curr_rsv |= (((u8) cr) & 0x01))
177
178 /*
179 * In the remaining five macros, 'info' is pointer to FRMR info field
180 * structure; 'ind' is a byte containing the bit value to set in the
181 * lowest-order bit)
182 */
183 #define FRMR_INFO_SET_INVALID_PDU_CTRL_IND(info, ind) \
184 (info->ind_bits = ((info->ind_bits & 0xFE) | (((u8) ind) & 0x01)))
185
186 #define FRMR_INFO_SET_INVALID_PDU_INFO_IND(info, ind) \
187 (info->ind_bits = ( (info->ind_bits & 0xFD) | (((u8) ind) & 0x02)))
188
189 #define FRMR_INFO_SET_PDU_INFO_2LONG_IND(info, ind) \
190 (info->ind_bits = ( (info->ind_bits & 0xFB) | (((u8) ind) & 0x04)))
191
192 #define FRMR_INFO_SET_PDU_INVALID_Nr_IND(info, ind) \
193 (info->ind_bits = ( (info->ind_bits & 0xF7) | (((u8) ind) & 0x08)))
194
195 #define FRMR_INFO_SET_PDU_INVALID_Ns_IND(info, ind) \
196 (info->ind_bits = ( (info->ind_bits & 0xEF) | (((u8) ind) & 0x10)))
197
198 /* Sequence-numbered PDU format (4 bytes in length) */
199 struct llc_pdu_sn {
200 u8 dsap;
201 u8 ssap;
202 u8 ctrl_1;
203 u8 ctrl_2;
204 } __packed;
205
llc_pdu_sn_hdr(struct sk_buff * skb)206 static inline struct llc_pdu_sn *llc_pdu_sn_hdr(struct sk_buff *skb)
207 {
208 return (struct llc_pdu_sn *)skb_network_header(skb);
209 }
210
211 /* Un-numbered PDU format (3 bytes in length) */
212 struct llc_pdu_un {
213 u8 dsap;
214 u8 ssap;
215 u8 ctrl_1;
216 } __packed;
217
llc_pdu_un_hdr(struct sk_buff * skb)218 static inline struct llc_pdu_un *llc_pdu_un_hdr(struct sk_buff *skb)
219 {
220 return (struct llc_pdu_un *)skb_network_header(skb);
221 }
222
223 /**
224 * llc_pdu_header_init - initializes pdu header
225 * @skb: input skb that header must be set into it.
226 * @type: type of PDU (U, I or S).
227 * @ssap: source sap.
228 * @dsap: destination sap.
229 * @cr: command/response bit (0 or 1).
230 *
231 * This function sets DSAP, SSAP and command/Response bit in LLC header.
232 */
llc_pdu_header_init(struct sk_buff * skb,u8 type,u8 ssap,u8 dsap,u8 cr)233 static inline void llc_pdu_header_init(struct sk_buff *skb, u8 type,
234 u8 ssap, u8 dsap, u8 cr)
235 {
236 int hlen = 4; /* default value for I and S types */
237 struct llc_pdu_un *pdu;
238
239 switch (type) {
240 case LLC_PDU_TYPE_U:
241 hlen = 3;
242 break;
243 case LLC_PDU_TYPE_U_XID:
244 hlen = 6;
245 break;
246 }
247
248 skb_push(skb, hlen);
249 skb_reset_network_header(skb);
250 pdu = llc_pdu_un_hdr(skb);
251 pdu->dsap = dsap;
252 pdu->ssap = ssap;
253 pdu->ssap |= cr;
254 }
255
256 /**
257 * llc_pdu_decode_sa - extracs source address (MAC) of input frame
258 * @skb: input skb that source address must be extracted from it.
259 * @sa: pointer to source address (6 byte array).
260 *
261 * This function extracts source address(MAC) of input frame.
262 */
llc_pdu_decode_sa(struct sk_buff * skb,u8 * sa)263 static inline void llc_pdu_decode_sa(struct sk_buff *skb, u8 *sa)
264 {
265 if (skb->protocol == htons(ETH_P_802_2))
266 memcpy(sa, eth_hdr(skb)->h_source, ETH_ALEN);
267 }
268
269 /**
270 * llc_pdu_decode_da - extracts dest address of input frame
271 * @skb: input skb that destination address must be extracted from it
272 * @da: pointer to destination address (6 byte array).
273 *
274 * This function extracts destination address(MAC) of input frame.
275 */
llc_pdu_decode_da(struct sk_buff * skb,u8 * da)276 static inline void llc_pdu_decode_da(struct sk_buff *skb, u8 *da)
277 {
278 if (skb->protocol == htons(ETH_P_802_2))
279 memcpy(da, eth_hdr(skb)->h_dest, ETH_ALEN);
280 }
281
282 /**
283 * llc_pdu_decode_ssap - extracts source SAP of input frame
284 * @skb: input skb that source SAP must be extracted from it.
285 * @ssap: source SAP (output argument).
286 *
287 * This function extracts source SAP of input frame. Right bit of SSAP is
288 * command/response bit.
289 */
llc_pdu_decode_ssap(struct sk_buff * skb,u8 * ssap)290 static inline void llc_pdu_decode_ssap(struct sk_buff *skb, u8 *ssap)
291 {
292 *ssap = llc_pdu_un_hdr(skb)->ssap & 0xFE;
293 }
294
295 /**
296 * llc_pdu_decode_dsap - extracts dest SAP of input frame
297 * @skb: input skb that destination SAP must be extracted from it.
298 * @dsap: destination SAP (output argument).
299 *
300 * This function extracts destination SAP of input frame. right bit of
301 * DSAP designates individual/group SAP.
302 */
llc_pdu_decode_dsap(struct sk_buff * skb,u8 * dsap)303 static inline void llc_pdu_decode_dsap(struct sk_buff *skb, u8 *dsap)
304 {
305 *dsap = llc_pdu_un_hdr(skb)->dsap & 0xFE;
306 }
307
308 /**
309 * llc_pdu_init_as_ui_cmd - sets LLC header as UI PDU
310 * @skb: input skb that header must be set into it.
311 *
312 * This function sets third byte of LLC header as a UI PDU.
313 */
llc_pdu_init_as_ui_cmd(struct sk_buff * skb)314 static inline void llc_pdu_init_as_ui_cmd(struct sk_buff *skb)
315 {
316 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
317
318 pdu->ctrl_1 = LLC_PDU_TYPE_U;
319 pdu->ctrl_1 |= LLC_1_PDU_CMD_UI;
320 }
321
322 /**
323 * llc_pdu_init_as_test_cmd - sets PDU as TEST
324 * @skb: Address of the skb to build
325 *
326 * Sets a PDU as TEST
327 */
llc_pdu_init_as_test_cmd(struct sk_buff * skb)328 static inline void llc_pdu_init_as_test_cmd(struct sk_buff *skb)
329 {
330 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
331
332 pdu->ctrl_1 = LLC_PDU_TYPE_U;
333 pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
334 pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
335 }
336
337 /**
338 * llc_pdu_init_as_test_rsp - build TEST response PDU
339 * @skb: Address of the skb to build
340 * @ev_skb: The received TEST command PDU frame
341 *
342 * Builds a pdu frame as a TEST response.
343 */
llc_pdu_init_as_test_rsp(struct sk_buff * skb,struct sk_buff * ev_skb)344 static inline void llc_pdu_init_as_test_rsp(struct sk_buff *skb,
345 struct sk_buff *ev_skb)
346 {
347 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
348
349 pdu->ctrl_1 = LLC_PDU_TYPE_U;
350 pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
351 pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
352 if (ev_skb->protocol == htons(ETH_P_802_2)) {
353 struct llc_pdu_un *ev_pdu = llc_pdu_un_hdr(ev_skb);
354 int dsize;
355
356 dsize = ntohs(eth_hdr(ev_skb)->h_proto) - 3;
357 memcpy(((u8 *)pdu) + 3, ((u8 *)ev_pdu) + 3, dsize);
358 skb_put(skb, dsize);
359 }
360 }
361
362 /* LLC Type 1 XID command/response information fields format */
363 struct llc_xid_info {
364 u8 fmt_id; /* always 0x81 for LLC */
365 u8 type; /* different if NULL/non-NULL LSAP */
366 u8 rw; /* sender receive window */
367 } __packed;
368
369 /**
370 * llc_pdu_init_as_xid_cmd - sets bytes 3, 4 & 5 of LLC header as XID
371 * @skb: input skb that header must be set into it.
372 * @svcs_supported: The class of the LLC (I or II)
373 * @rx_window: The size of the receive window of the LLC
374 *
375 * This function sets third,fourth,fifth and sixth bytes of LLC header as
376 * a XID PDU.
377 */
llc_pdu_init_as_xid_cmd(struct sk_buff * skb,u8 svcs_supported,u8 rx_window)378 static inline void llc_pdu_init_as_xid_cmd(struct sk_buff *skb,
379 u8 svcs_supported, u8 rx_window)
380 {
381 struct llc_xid_info *xid_info;
382 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
383
384 pdu->ctrl_1 = LLC_PDU_TYPE_U;
385 pdu->ctrl_1 |= LLC_1_PDU_CMD_XID;
386 pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
387 xid_info = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
388 xid_info->fmt_id = LLC_XID_FMT_ID; /* 0x81 */
389 xid_info->type = svcs_supported;
390 xid_info->rw = rx_window << 1; /* size of receive window */
391
392 /* no need to push/put since llc_pdu_header_init() has already
393 * pushed 3 + 3 bytes
394 */
395 }
396
397 /**
398 * llc_pdu_init_as_xid_rsp - builds XID response PDU
399 * @skb: Address of the skb to build
400 * @svcs_supported: The class of the LLC (I or II)
401 * @rx_window: The size of the receive window of the LLC
402 *
403 * Builds a pdu frame as an XID response.
404 */
llc_pdu_init_as_xid_rsp(struct sk_buff * skb,u8 svcs_supported,u8 rx_window)405 static inline void llc_pdu_init_as_xid_rsp(struct sk_buff *skb,
406 u8 svcs_supported, u8 rx_window)
407 {
408 struct llc_xid_info *xid_info;
409 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
410
411 pdu->ctrl_1 = LLC_PDU_TYPE_U;
412 pdu->ctrl_1 |= LLC_1_PDU_CMD_XID;
413 pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
414
415 xid_info = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
416 xid_info->fmt_id = LLC_XID_FMT_ID;
417 xid_info->type = svcs_supported;
418 xid_info->rw = rx_window << 1;
419 skb_put(skb, sizeof(struct llc_xid_info));
420 }
421
422 /* LLC Type 2 FRMR response information field format */
423 struct llc_frmr_info {
424 u16 rej_pdu_ctrl; /* bits 1-8 if U-PDU */
425 u8 curr_ssv; /* current send state variable val */
426 u8 curr_rsv; /* current receive state variable */
427 u8 ind_bits; /* indicator bits set with macro */
428 } __packed;
429
430 void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 type);
431 void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value);
432 void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit);
433 void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit);
434 void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr);
435 void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
436 void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
437 void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
438 void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit);
439 void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit);
440 void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb, struct llc_pdu_sn *prev_pdu,
441 u8 f_bit, u8 vs, u8 vr, u8 vzyxw);
442 void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
443 void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
444 void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
445 void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit);
446 #endif /* LLC_PDU_H */
447
