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