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 #include <linux/if_tr.h>
17
18 /* Lengths of frame formats */
19 #define LLC_PDU_LEN_I 4 /* header and 2 control bytes */
20 #define LLC_PDU_LEN_S 4
21 #define LLC_PDU_LEN_U 3 /* header and 1 control byte */
22 /* Known SAP addresses */
23 #define LLC_GLOBAL_SAP 0xFF
24 #define LLC_NULL_SAP 0x00 /* not network-layer visible */
25 #define LLC_MGMT_INDIV 0x02 /* station LLC mgmt indiv addr */
26 #define LLC_MGMT_GRP 0x03 /* station LLC mgmt group addr */
27 #define LLC_RDE_SAP 0xA6 /* route ... */
28
29 /* SAP field bit masks */
30 #define LLC_ISO_RESERVED_SAP 0x02
31 #define LLC_SAP_GROUP_DSAP 0x01
32 #define LLC_SAP_RESP_SSAP 0x01
33
34 /* Group/individual DSAP indicator is DSAP field */
35 #define LLC_PDU_GROUP_DSAP_MASK 0x01
36 #define LLC_PDU_IS_GROUP_DSAP(pdu) \
37 ((pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
38 #define LLC_PDU_IS_INDIV_DSAP(pdu) \
39 (!(pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
40
41 /* Command/response PDU indicator in SSAP field */
42 #define LLC_PDU_CMD_RSP_MASK 0x01
43 #define LLC_PDU_CMD 0
44 #define LLC_PDU_RSP 1
45 #define LLC_PDU_IS_CMD(pdu) ((pdu->ssap & LLC_PDU_RSP) ? 0 : 1)
46 #define LLC_PDU_IS_RSP(pdu) ((pdu->ssap & LLC_PDU_RSP) ? 1 : 0)
47
48 /* Get PDU type from 2 lowest-order bits of control field first byte */
49 #define LLC_PDU_TYPE_I_MASK 0x01 /* 16-bit control field */
50 #define LLC_PDU_TYPE_S_MASK 0x03
51 #define LLC_PDU_TYPE_U_MASK 0x03 /* 8-bit control field */
52 #define LLC_PDU_TYPE_MASK 0x03
53
54 #define LLC_PDU_TYPE_I 0 /* first bit */
55 #define LLC_PDU_TYPE_S 1 /* first two bits */
56 #define LLC_PDU_TYPE_U 3 /* first two bits */
57
58 #define LLC_PDU_TYPE_IS_I(pdu) \
59 ((!(pdu->ctrl_1 & LLC_PDU_TYPE_I_MASK)) ? 1 : 0)
60
61 #define LLC_PDU_TYPE_IS_U(pdu) \
62 (((pdu->ctrl_1 & LLC_PDU_TYPE_U_MASK) == LLC_PDU_TYPE_U) ? 1 : 0)
63
64 #define LLC_PDU_TYPE_IS_S(pdu) \
65 (((pdu->ctrl_1 & LLC_PDU_TYPE_S_MASK) == LLC_PDU_TYPE_S) ? 1 : 0)
66
67 /* U-format PDU control field masks */
68 #define LLC_U_PF_BIT_MASK 0x10 /* P/F bit mask */
69 #define LLC_U_PF_IS_1(pdu) ((pdu->ctrl_1 & LLC_U_PF_BIT_MASK) ? 1 : 0)
70 #define LLC_U_PF_IS_0(pdu) ((!(pdu->ctrl_1 & LLC_U_PF_BIT_MASK)) ? 1 : 0)
71
72 #define LLC_U_PDU_CMD_MASK 0xEC /* cmd/rsp mask */
73 #define LLC_U_PDU_CMD(pdu) (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
74 #define LLC_U_PDU_RSP(pdu) (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
75
76 #define LLC_1_PDU_CMD_UI 0x00 /* Type 1 cmds/rsps */
77 #define LLC_1_PDU_CMD_XID 0xAC
78 #define LLC_1_PDU_CMD_TEST 0xE0
79
80 #define LLC_2_PDU_CMD_SABME 0x6C /* Type 2 cmds/rsps */
81 #define LLC_2_PDU_CMD_DISC 0x40
82 #define LLC_2_PDU_RSP_UA 0x60
83 #define LLC_2_PDU_RSP_DM 0x0C
84 #define LLC_2_PDU_RSP_FRMR 0x84
85
86 /* Type 1 operations */
87
88 /* XID information field bit masks */
89
90 /* LLC format identifier (byte 1) */
91 #define LLC_XID_FMT_ID 0x81 /* first byte must be this */
92
93 /* LLC types/classes identifier (byte 2) */
94 #define LLC_XID_CLASS_ZEROS_MASK 0xE0 /* these must be zeros */
95 #define LLC_XID_CLASS_MASK 0x1F /* AND with byte to get below */
96
97 #define LLC_XID_NULL_CLASS_1 0x01 /* if NULL LSAP...use these */
98 #define LLC_XID_NULL_CLASS_2 0x03
99 #define LLC_XID_NULL_CLASS_3 0x05
100 #define LLC_XID_NULL_CLASS_4 0x07
101
102 #define LLC_XID_NNULL_TYPE_1 0x01 /* if non-NULL LSAP...use these */
103 #define LLC_XID_NNULL_TYPE_2 0x02
104 #define LLC_XID_NNULL_TYPE_3 0x04
105 #define LLC_XID_NNULL_TYPE_1_2 0x03
106 #define LLC_XID_NNULL_TYPE_1_3 0x05
107 #define LLC_XID_NNULL_TYPE_2_3 0x06
108 #define LLC_XID_NNULL_ALL 0x07
109
110 /* Sender Receive Window (byte 3) */
111 #define LLC_XID_RW_MASK 0xFE /* AND with value to get below */
112
113 #define LLC_XID_MIN_RW 0x02 /* lowest-order bit always zero */
114
115 /* Type 2 operations */
116
117 #define LLC_2_SEQ_NBR_MODULO ((u8) 128)
118
119 /* I-PDU masks ('ctrl' is I-PDU control word) */
120 #define LLC_I_GET_NS(pdu) (u8)((pdu->ctrl_1 & 0xFE) >> 1)
121 #define LLC_I_GET_NR(pdu) (u8)((pdu->ctrl_2 & 0xFE) >> 1)
122
123 #define LLC_I_PF_BIT_MASK 0x01
124
125 #define LLC_I_PF_IS_0(pdu) ((!(pdu->ctrl_2 & LLC_I_PF_BIT_MASK)) ? 1 : 0)
126 #define LLC_I_PF_IS_1(pdu) ((pdu->ctrl_2 & LLC_I_PF_BIT_MASK) ? 1 : 0)
127
128 /* S-PDU supervisory commands and responses */
129
130 #define LLC_S_PDU_CMD_MASK 0x0C
131 #define LLC_S_PDU_CMD(pdu) (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
132 #define LLC_S_PDU_RSP(pdu) (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
133
134 #define LLC_2_PDU_CMD_RR 0x00 /* rx ready cmd */
135 #define LLC_2_PDU_RSP_RR 0x00 /* rx ready rsp */
136 #define LLC_2_PDU_CMD_REJ 0x08 /* reject PDU cmd */
137 #define LLC_2_PDU_RSP_REJ 0x08 /* reject PDU rsp */
138 #define LLC_2_PDU_CMD_RNR 0x04 /* rx not ready cmd */
139 #define LLC_2_PDU_RSP_RNR 0x04 /* rx not ready rsp */
140
141 #define LLC_S_PF_BIT_MASK 0x01
142 #define LLC_S_PF_IS_0(pdu) ((!(pdu->ctrl_2 & LLC_S_PF_BIT_MASK)) ? 1 : 0)
143 #define LLC_S_PF_IS_1(pdu) ((pdu->ctrl_2 & LLC_S_PF_BIT_MASK) ? 1 : 0)
144
145 #define PDU_SUPV_GET_Nr(pdu) ((pdu->ctrl_2 & 0xFE) >> 1)
146 #define PDU_GET_NEXT_Vr(sn) (++sn & ~LLC_2_SEQ_NBR_MODULO)
147
148 /* FRMR information field macros */
149
150 #define FRMR_INFO_LENGTH 5 /* 5 bytes of information */
151
152 /*
153 * info is pointer to FRMR info field structure; 'rej_ctrl' is byte pointer
154 * (if U-PDU) or word pointer to rejected PDU control field
155 */
156 #define FRMR_INFO_SET_REJ_CNTRL(info,rej_ctrl) \
157 info->rej_pdu_ctrl = ((*((u8 *) rej_ctrl) & \
158 LLC_PDU_TYPE_U) != LLC_PDU_TYPE_U ? \
159 (u16)*((u16 *) rej_ctrl) : \
160 (((u16) *((u8 *) rej_ctrl)) & 0x00FF))
161
162 /*
163 * Info is pointer to FRMR info field structure; 'vs' is a byte containing
164 * send state variable value in low-order 7 bits (insure the lowest-order
165 * bit remains zero (0))
166 */
167 #define FRMR_INFO_SET_Vs(info,vs) (info->curr_ssv = (((u8) vs) << 1))
168 #define FRMR_INFO_SET_Vr(info,vr) (info->curr_rsv = (((u8) vr) << 1))
169
170 /*
171 * Info is pointer to FRMR info field structure; 'cr' is a byte containing
172 * the C/R bit value in the low-order bit
173 */
174 #define FRMR_INFO_SET_C_R_BIT(info, cr) (info->curr_rsv |= (((u8) cr) & 0x01))
175
176 /*
177 * In the remaining five macros, 'info' is pointer to FRMR info field
178 * structure; 'ind' is a byte containing the bit value to set in the
179 * lowest-order bit)
180 */
181 #define FRMR_INFO_SET_INVALID_PDU_CTRL_IND(info, ind) \
182 (info->ind_bits = ((info->ind_bits & 0xFE) | (((u8) ind) & 0x01)))
183
184 #define FRMR_INFO_SET_INVALID_PDU_INFO_IND(info, ind) \
185 (info->ind_bits = ( (info->ind_bits & 0xFD) | (((u8) ind) & 0x02)))
186
187 #define FRMR_INFO_SET_PDU_INFO_2LONG_IND(info, ind) \
188 (info->ind_bits = ( (info->ind_bits & 0xFB) | (((u8) ind) & 0x04)))
189
190 #define FRMR_INFO_SET_PDU_INVALID_Nr_IND(info, ind) \
191 (info->ind_bits = ( (info->ind_bits & 0xF7) | (((u8) ind) & 0x08)))
192
193 #define FRMR_INFO_SET_PDU_INVALID_Ns_IND(info, ind) \
194 (info->ind_bits = ( (info->ind_bits & 0xEF) | (((u8) ind) & 0x10)))
195
196 /* Sequence-numbered PDU format (4 bytes in length) */
197 struct llc_pdu_sn {
198 u8 dsap;
199 u8 ssap;
200 u8 ctrl_1;
201 u8 ctrl_2;
202 } __packed;
203
llc_pdu_sn_hdr(struct sk_buff * skb)204 static inline struct llc_pdu_sn *llc_pdu_sn_hdr(struct sk_buff *skb)
205 {
206 return (struct llc_pdu_sn *)skb_network_header(skb);
207 }
208
209 /* Un-numbered PDU format (3 bytes in length) */
210 struct llc_pdu_un {
211 u8 dsap;
212 u8 ssap;
213 u8 ctrl_1;
214 } __packed;
215
llc_pdu_un_hdr(struct sk_buff * skb)216 static inline struct llc_pdu_un *llc_pdu_un_hdr(struct sk_buff *skb)
217 {
218 return (struct llc_pdu_un *)skb_network_header(skb);
219 }
220
221 /**
222 * llc_pdu_header_init - initializes pdu header
223 * @skb: input skb that header must be set into it.
224 * @type: type of PDU (U, I or S).
225 * @ssap: source sap.
226 * @dsap: destination sap.
227 * @cr: command/response bit (0 or 1).
228 *
229 * This function sets DSAP, SSAP and command/Response bit in LLC header.
230 */
llc_pdu_header_init(struct sk_buff * skb,u8 type,u8 ssap,u8 dsap,u8 cr)231 static inline void llc_pdu_header_init(struct sk_buff *skb, u8 type,
232 u8 ssap, u8 dsap, u8 cr)
233 {
234 const int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
235 struct llc_pdu_un *pdu;
236
237 skb_push(skb, hlen);
238 skb_reset_network_header(skb);
239 pdu = llc_pdu_un_hdr(skb);
240 pdu->dsap = dsap;
241 pdu->ssap = ssap;
242 pdu->ssap |= cr;
243 }
244
245 /**
246 * llc_pdu_decode_sa - extracs source address (MAC) of input frame
247 * @skb: input skb that source address must be extracted from it.
248 * @sa: pointer to source address (6 byte array).
249 *
250 * This function extracts source address(MAC) of input frame.
251 */
llc_pdu_decode_sa(struct sk_buff * skb,u8 * sa)252 static inline void llc_pdu_decode_sa(struct sk_buff *skb, u8 *sa)
253 {
254 if (skb->protocol == htons(ETH_P_802_2))
255 memcpy(sa, eth_hdr(skb)->h_source, ETH_ALEN);
256 else if (skb->protocol == htons(ETH_P_TR_802_2)) {
257 memcpy(sa, tr_hdr(skb)->saddr, ETH_ALEN);
258 *sa &= 0x7F;
259 }
260 }
261
262 /**
263 * llc_pdu_decode_da - extracts dest address of input frame
264 * @skb: input skb that destination address must be extracted from it
265 * @sa: pointer to destination address (6 byte array).
266 *
267 * This function extracts destination address(MAC) of input frame.
268 */
llc_pdu_decode_da(struct sk_buff * skb,u8 * da)269 static inline void llc_pdu_decode_da(struct sk_buff *skb, u8 *da)
270 {
271 if (skb->protocol == htons(ETH_P_802_2))
272 memcpy(da, eth_hdr(skb)->h_dest, ETH_ALEN);
273 else if (skb->protocol == htons(ETH_P_TR_802_2))
274 memcpy(da, tr_hdr(skb)->daddr, ETH_ALEN);
275 }
276
277 /**
278 * llc_pdu_decode_ssap - extracts source SAP of input frame
279 * @skb: input skb that source SAP must be extracted from it.
280 * @ssap: source SAP (output argument).
281 *
282 * This function extracts source SAP of input frame. Right bit of SSAP is
283 * command/response bit.
284 */
llc_pdu_decode_ssap(struct sk_buff * skb,u8 * ssap)285 static inline void llc_pdu_decode_ssap(struct sk_buff *skb, u8 *ssap)
286 {
287 *ssap = llc_pdu_un_hdr(skb)->ssap & 0xFE;
288 }
289
290 /**
291 * llc_pdu_decode_dsap - extracts dest SAP of input frame
292 * @skb: input skb that destination SAP must be extracted from it.
293 * @dsap: destination SAP (output argument).
294 *
295 * This function extracts destination SAP of input frame. right bit of
296 * DSAP designates individual/group SAP.
297 */
llc_pdu_decode_dsap(struct sk_buff * skb,u8 * dsap)298 static inline void llc_pdu_decode_dsap(struct sk_buff *skb, u8 *dsap)
299 {
300 *dsap = llc_pdu_un_hdr(skb)->dsap & 0xFE;
301 }
302
303 /**
304 * llc_pdu_init_as_ui_cmd - sets LLC header as UI PDU
305 * @skb: input skb that header must be set into it.
306 *
307 * This function sets third byte of LLC header as a UI PDU.
308 */
llc_pdu_init_as_ui_cmd(struct sk_buff * skb)309 static inline void llc_pdu_init_as_ui_cmd(struct sk_buff *skb)
310 {
311 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
312
313 pdu->ctrl_1 = LLC_PDU_TYPE_U;
314 pdu->ctrl_1 |= LLC_1_PDU_CMD_UI;
315 }
316
317 /**
318 * llc_pdu_init_as_test_cmd - sets PDU as TEST
319 * @skb - Address of the skb to build
320 *
321 * Sets a PDU as TEST
322 */
llc_pdu_init_as_test_cmd(struct sk_buff * skb)323 static inline void llc_pdu_init_as_test_cmd(struct sk_buff *skb)
324 {
325 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
326
327 pdu->ctrl_1 = LLC_PDU_TYPE_U;
328 pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
329 pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
330 }
331
332 /**
333 * llc_pdu_init_as_test_rsp - build TEST response PDU
334 * @skb: Address of the skb to build
335 * @ev_skb: The received TEST command PDU frame
336 *
337 * Builds a pdu frame as a TEST response.
338 */
llc_pdu_init_as_test_rsp(struct sk_buff * skb,struct sk_buff * ev_skb)339 static inline void llc_pdu_init_as_test_rsp(struct sk_buff *skb,
340 struct sk_buff *ev_skb)
341 {
342 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
343
344 pdu->ctrl_1 = LLC_PDU_TYPE_U;
345 pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
346 pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
347 if (ev_skb->protocol == htons(ETH_P_802_2)) {
348 struct llc_pdu_un *ev_pdu = llc_pdu_un_hdr(ev_skb);
349 int dsize;
350
351 dsize = ntohs(eth_hdr(ev_skb)->h_proto) - 3;
352 memcpy(((u8 *)pdu) + 3, ((u8 *)ev_pdu) + 3, dsize);
353 skb_put(skb, dsize);
354 }
355 }
356
357 /* LLC Type 1 XID command/response information fields format */
358 struct llc_xid_info {
359 u8 fmt_id; /* always 0x81 for LLC */
360 u8 type; /* different if NULL/non-NULL LSAP */
361 u8 rw; /* sender receive window */
362 } __packed;
363
364 /**
365 * llc_pdu_init_as_xid_cmd - sets bytes 3, 4 & 5 of LLC header as XID
366 * @skb: input skb that header must be set into it.
367 *
368 * This function sets third,fourth,fifth and sixth bytes of LLC header as
369 * a XID PDU.
370 */
llc_pdu_init_as_xid_cmd(struct sk_buff * skb,u8 svcs_supported,u8 rx_window)371 static inline void llc_pdu_init_as_xid_cmd(struct sk_buff *skb,
372 u8 svcs_supported, u8 rx_window)
373 {
374 struct llc_xid_info *xid_info;
375 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
376
377 pdu->ctrl_1 = LLC_PDU_TYPE_U;
378 pdu->ctrl_1 |= LLC_1_PDU_CMD_XID;
379 pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
380 xid_info = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
381 xid_info->fmt_id = LLC_XID_FMT_ID; /* 0x81 */
382 xid_info->type = svcs_supported;
383 xid_info->rw = rx_window << 1; /* size of receive window */
384 skb_put(skb, sizeof(struct llc_xid_info));
385 }
386
387 /**
388 * llc_pdu_init_as_xid_rsp - builds XID response PDU
389 * @skb: Address of the skb to build
390 * @svcs_supported: The class of the LLC (I or II)
391 * @rx_window: The size of the receive window of the LLC
392 *
393 * Builds a pdu frame as an XID response.
394 */
llc_pdu_init_as_xid_rsp(struct sk_buff * skb,u8 svcs_supported,u8 rx_window)395 static inline void llc_pdu_init_as_xid_rsp(struct sk_buff *skb,
396 u8 svcs_supported, u8 rx_window)
397 {
398 struct llc_xid_info *xid_info;
399 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
400
401 pdu->ctrl_1 = LLC_PDU_TYPE_U;
402 pdu->ctrl_1 |= LLC_1_PDU_CMD_XID;
403 pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
404
405 xid_info = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
406 xid_info->fmt_id = LLC_XID_FMT_ID;
407 xid_info->type = svcs_supported;
408 xid_info->rw = rx_window << 1;
409 skb_put(skb, sizeof(struct llc_xid_info));
410 }
411
412 /* LLC Type 2 FRMR response information field format */
413 struct llc_frmr_info {
414 u16 rej_pdu_ctrl; /* bits 1-8 if U-PDU */
415 u8 curr_ssv; /* current send state variable val */
416 u8 curr_rsv; /* current receive state variable */
417 u8 ind_bits; /* indicator bits set with macro */
418 } __packed;
419
420 extern void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 type);
421 extern void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value);
422 extern void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit);
423 extern void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit);
424 extern void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr);
425 extern void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
426 extern void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
427 extern void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
428 extern void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit);
429 extern void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit);
430 extern void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb,
431 struct llc_pdu_sn *prev_pdu,
432 u8 f_bit, u8 vs, u8 vr, u8 vzyxw);
433 extern void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
434 extern void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
435 extern void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
436 extern void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit);
437 #endif /* LLC_PDU_H */
438