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  *	@sa: 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  *
373  *	This function sets third,fourth,fifth and sixth bytes of LLC header as
374  *	a XID PDU.
375  */
llc_pdu_init_as_xid_cmd(struct sk_buff * skb,u8 svcs_supported,u8 rx_window)376 static inline void llc_pdu_init_as_xid_cmd(struct sk_buff *skb,
377 					   u8 svcs_supported, u8 rx_window)
378 {
379 	struct llc_xid_info *xid_info;
380 	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
381 
382 	pdu->ctrl_1	 = LLC_PDU_TYPE_U;
383 	pdu->ctrl_1	|= LLC_1_PDU_CMD_XID;
384 	pdu->ctrl_1	|= LLC_U_PF_BIT_MASK;
385 	xid_info	 = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
386 	xid_info->fmt_id = LLC_XID_FMT_ID;	/* 0x81 */
387 	xid_info->type	 = svcs_supported;
388 	xid_info->rw	 = rx_window << 1;	/* size of receive window */
389 
390 	/* no need to push/put since llc_pdu_header_init() has already
391 	 * pushed 3 + 3 bytes
392 	 */
393 }
394 
395 /**
396  *	llc_pdu_init_as_xid_rsp - builds XID response PDU
397  *	@skb: Address of the skb to build
398  *	@svcs_supported: The class of the LLC (I or II)
399  *	@rx_window: The size of the receive window of the LLC
400  *
401  *	Builds a pdu frame as an XID response.
402  */
llc_pdu_init_as_xid_rsp(struct sk_buff * skb,u8 svcs_supported,u8 rx_window)403 static inline void llc_pdu_init_as_xid_rsp(struct sk_buff *skb,
404 					   u8 svcs_supported, u8 rx_window)
405 {
406 	struct llc_xid_info *xid_info;
407 	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
408 
409 	pdu->ctrl_1	 = LLC_PDU_TYPE_U;
410 	pdu->ctrl_1	|= LLC_1_PDU_CMD_XID;
411 	pdu->ctrl_1	|= LLC_U_PF_BIT_MASK;
412 
413 	xid_info	 = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
414 	xid_info->fmt_id = LLC_XID_FMT_ID;
415 	xid_info->type	 = svcs_supported;
416 	xid_info->rw	 = rx_window << 1;
417 	skb_put(skb, sizeof(struct llc_xid_info));
418 }
419 
420 /* LLC Type 2 FRMR response information field format */
421 struct llc_frmr_info {
422 	u16 rej_pdu_ctrl;	/* bits 1-8 if U-PDU */
423 	u8  curr_ssv;		/* current send state variable val */
424 	u8  curr_rsv;		/* current receive state variable */
425 	u8  ind_bits;		/* indicator bits set with macro */
426 } __packed;
427 
428 void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 type);
429 void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value);
430 void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit);
431 void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit);
432 void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr);
433 void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
434 void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
435 void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
436 void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit);
437 void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit);
438 void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb, struct llc_pdu_sn *prev_pdu,
439 			      u8 f_bit, u8 vs, u8 vr, u8 vzyxw);
440 void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
441 void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
442 void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
443 void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit);
444 #endif /* LLC_PDU_H */
445