include/net/llc_pdu.h - kernel/msm-4.9 - Gitiles

 #ifndef LLC_PDU_H
 #define LLC_PDU_H
 /*
  * Copyright (c) 1997 by Procom Technology,Inc.
  * 		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  *
  * This program can be redistributed or modified under the terms of the
  * GNU General Public License as published by the Free Software Foundation.
  * This program is distributed without any warranty or implied warranty
  * of merchantability or fitness for a particular purpose.
  *
  * See the GNU General Public License for more details.
  */

 #include <linux/if_ether.h>
 #include <linux/if_tr.h>

 /* Lengths of frame formats */
 #define LLC_PDU_LEN_I	4       /* header and 2 control bytes */
 #define LLC_PDU_LEN_S	4
 #define LLC_PDU_LEN_U	3       /* header and 1 control byte */
 /* Known SAP addresses */
 #define LLC_GLOBAL_SAP	0xFF
 #define LLC_NULL_SAP	0x00	/* not network-layer visible */
 #define LLC_MGMT_INDIV	0x02	/* station LLC mgmt indiv addr */
 #define LLC_MGMT_GRP	0x03	/* station LLC mgmt group addr */
 #define LLC_RDE_SAP	0xA6	/* route ... */

 /* SAP field bit masks */
 #define LLC_ISO_RESERVED_SAP	0x02
 #define LLC_SAP_GROUP_DSAP	0x01
 #define LLC_SAP_RESP_SSAP	0x01

 /* Group/individual DSAP indicator is DSAP field */
 #define LLC_PDU_GROUP_DSAP_MASK    0x01
 #define LLC_PDU_IS_GROUP_DSAP(pdu)      \
 	((pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
 #define LLC_PDU_IS_INDIV_DSAP(pdu)      \
 	(!(pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)

 /* Command/response PDU indicator in SSAP field */
 #define LLC_PDU_CMD_RSP_MASK	0x01
 #define LLC_PDU_CMD		0
 #define LLC_PDU_RSP		1
 #define LLC_PDU_IS_CMD(pdu)    ((pdu->ssap & LLC_PDU_RSP) ? 0 : 1)
 #define LLC_PDU_IS_RSP(pdu)    ((pdu->ssap & LLC_PDU_RSP) ? 1 : 0)

 /* Get PDU type from 2 lowest-order bits of control field first byte */
 #define LLC_PDU_TYPE_I_MASK    0x01	/* 16-bit control field */
 #define LLC_PDU_TYPE_S_MASK    0x03
 #define LLC_PDU_TYPE_U_MASK    0x03	/* 8-bit control field */
 #define LLC_PDU_TYPE_MASK      0x03

 #define LLC_PDU_TYPE_I	0	/* first bit */
 #define LLC_PDU_TYPE_S	1	/* first two bits */
 #define LLC_PDU_TYPE_U	3	/* first two bits */

 #define LLC_PDU_TYPE_IS_I(pdu) \
 	((!(pdu->ctrl_1 & LLC_PDU_TYPE_I_MASK)) ? 1 : 0)

 #define LLC_PDU_TYPE_IS_U(pdu) \
 	(((pdu->ctrl_1 & LLC_PDU_TYPE_U_MASK) == LLC_PDU_TYPE_U) ? 1 : 0)

 #define LLC_PDU_TYPE_IS_S(pdu) \
 	(((pdu->ctrl_1 & LLC_PDU_TYPE_S_MASK) == LLC_PDU_TYPE_S) ? 1 : 0)

 /* U-format PDU control field masks */
 #define LLC_U_PF_BIT_MASK      0x10	/* P/F bit mask */
 #define LLC_U_PF_IS_1(pdu)     ((pdu->ctrl_1 & LLC_U_PF_BIT_MASK) ? 1 : 0)
 #define LLC_U_PF_IS_0(pdu)     ((!(pdu->ctrl_1 & LLC_U_PF_BIT_MASK)) ? 1 : 0)

 #define LLC_U_PDU_CMD_MASK     0xEC	/* cmd/rsp mask */
 #define LLC_U_PDU_CMD(pdu)     (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
 #define LLC_U_PDU_RSP(pdu)     (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)

 #define LLC_1_PDU_CMD_UI       0x00	/* Type 1 cmds/rsps */
 #define LLC_1_PDU_CMD_XID      0xAC
 #define LLC_1_PDU_CMD_TEST     0xE0

 #define LLC_2_PDU_CMD_SABME    0x6C	/* Type 2 cmds/rsps */
 #define LLC_2_PDU_CMD_DISC     0x40
 #define LLC_2_PDU_RSP_UA       0x60
 #define LLC_2_PDU_RSP_DM       0x0C
 #define LLC_2_PDU_RSP_FRMR     0x84

 /* Type 1 operations */

 /* XID information field bit masks */

 /* LLC format identifier (byte 1) */
 #define LLC_XID_FMT_ID		0x81	/* first byte must be this */

 /* LLC types/classes identifier (byte 2) */
 #define LLC_XID_CLASS_ZEROS_MASK	0xE0	/* these must be zeros */
 #define LLC_XID_CLASS_MASK		0x1F	/* AND with byte to get below */

 #define LLC_XID_NULL_CLASS_1	0x01	/* if NULL LSAP...use these */
 #define LLC_XID_NULL_CLASS_2	0x03
 #define LLC_XID_NULL_CLASS_3	0x05
 #define LLC_XID_NULL_CLASS_4	0x07

 #define LLC_XID_NNULL_TYPE_1	0x01	/* if non-NULL LSAP...use these */
 #define LLC_XID_NNULL_TYPE_2	0x02
 #define LLC_XID_NNULL_TYPE_3	0x04
 #define LLC_XID_NNULL_TYPE_1_2	0x03
 #define LLC_XID_NNULL_TYPE_1_3	0x05
 #define LLC_XID_NNULL_TYPE_2_3	0x06
 #define LLC_XID_NNULL_ALL		0x07

 /* Sender Receive Window (byte 3) */
 #define LLC_XID_RW_MASK	0xFE	/* AND with value to get below */

 #define LLC_XID_MIN_RW	0x02	/* lowest-order bit always zero */

 /* Type 2 operations */

 #define LLC_2_SEQ_NBR_MODULO   ((u8) 128)

 /* I-PDU masks ('ctrl' is I-PDU control word) */
 #define LLC_I_GET_NS(pdu)     (u8)((pdu->ctrl_1 & 0xFE) >> 1)
 #define LLC_I_GET_NR(pdu)     (u8)((pdu->ctrl_2 & 0xFE) >> 1)

 #define LLC_I_PF_BIT_MASK      0x01

 #define LLC_I_PF_IS_0(pdu)     ((!(pdu->ctrl_2 & LLC_I_PF_BIT_MASK)) ? 1 : 0)
 #define LLC_I_PF_IS_1(pdu)     ((pdu->ctrl_2 & LLC_I_PF_BIT_MASK) ? 1 : 0)

 /* S-PDU supervisory commands and responses */

 #define LLC_S_PDU_CMD_MASK     0x0C
 #define LLC_S_PDU_CMD(pdu)     (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
 #define LLC_S_PDU_RSP(pdu)     (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)

 #define LLC_2_PDU_CMD_RR       0x00	/* rx ready cmd */
 #define LLC_2_PDU_RSP_RR       0x00	/* rx ready rsp */
 #define LLC_2_PDU_CMD_REJ      0x08	/* reject PDU cmd */
 #define LLC_2_PDU_RSP_REJ      0x08	/* reject PDU rsp */
 #define LLC_2_PDU_CMD_RNR      0x04	/* rx not ready cmd */
 #define LLC_2_PDU_RSP_RNR      0x04	/* rx not ready rsp */

 #define LLC_S_PF_BIT_MASK      0x01
 #define LLC_S_PF_IS_0(pdu)     ((!(pdu->ctrl_2 & LLC_S_PF_BIT_MASK)) ? 1 : 0)
 #define LLC_S_PF_IS_1(pdu)     ((pdu->ctrl_2 & LLC_S_PF_BIT_MASK) ? 1 : 0)

 #define PDU_SUPV_GET_Nr(pdu)   ((pdu->ctrl_2 & 0xFE) >> 1)
 #define PDU_GET_NEXT_Vr(sn)    (++sn & ~LLC_2_SEQ_NBR_MODULO)

 /* FRMR information field macros */

 #define FRMR_INFO_LENGTH       5	/* 5 bytes of information */

 /*
  * info is pointer to FRMR info field structure; 'rej_ctrl' is byte pointer
  * (if U-PDU) or word pointer to rejected PDU control field
  */
 #define FRMR_INFO_SET_REJ_CNTRL(info,rej_ctrl) \
 	info->rej_pdu_ctrl = ((*((u8 *) rej_ctrl) & \
 				LLC_PDU_TYPE_U) != LLC_PDU_TYPE_U ? \
 				(u16)*((u16 *) rej_ctrl) : \
 				(((u16) *((u8 *) rej_ctrl)) & 0x00FF))

 /*
  * Info is pointer to FRMR info field structure; 'vs' is a byte containing
  * send state variable value in low-order 7 bits (insure the lowest-order
  * bit remains zero (0))
  */
 #define FRMR_INFO_SET_Vs(info,vs) (info->curr_ssv = (((u8) vs) << 1))
 #define FRMR_INFO_SET_Vr(info,vr) (info->curr_rsv = (((u8) vr) << 1))

 /*
  * Info is pointer to FRMR info field structure; 'cr' is a byte containing
  * the C/R bit value in the low-order bit
  */
 #define FRMR_INFO_SET_C_R_BIT(info, cr)  (info->curr_rsv |= (((u8) cr) & 0x01))

 /*
  * In the remaining five macros, 'info' is pointer to FRMR info field
  * structure; 'ind' is a byte containing the bit value to set in the
  * lowest-order bit)
  */
 #define FRMR_INFO_SET_INVALID_PDU_CTRL_IND(info, ind) \
        (info->ind_bits = ((info->ind_bits & 0xFE) | (((u8) ind) & 0x01)))

 #define FRMR_INFO_SET_INVALID_PDU_INFO_IND(info, ind) \
        (info->ind_bits = ( (info->ind_bits & 0xFD) | (((u8) ind) & 0x02)))

 #define FRMR_INFO_SET_PDU_INFO_2LONG_IND(info, ind) \
        (info->ind_bits = ( (info->ind_bits & 0xFB) | (((u8) ind) & 0x04)))

 #define FRMR_INFO_SET_PDU_INVALID_Nr_IND(info, ind) \
        (info->ind_bits = ( (info->ind_bits & 0xF7) | (((u8) ind) & 0x08)))

 #define FRMR_INFO_SET_PDU_INVALID_Ns_IND(info, ind) \
        (info->ind_bits = ( (info->ind_bits & 0xEF) | (((u8) ind) & 0x10)))

 /* Sequence-numbered PDU format (4 bytes in length) */
 struct llc_pdu_sn {
 	u8 dsap;
 	u8 ssap;
 	u8 ctrl_1;
 	u8 ctrl_2;
 };

 static inline struct llc_pdu_sn *llc_pdu_sn_hdr(struct sk_buff *skb)
 {
 	return (struct llc_pdu_sn *)skb->nh.raw;
 }

 /* Un-numbered PDU format (3 bytes in length) */
 struct llc_pdu_un {
 	u8 dsap;
 	u8 ssap;
 	u8 ctrl_1;
 };

 static inline struct llc_pdu_un *llc_pdu_un_hdr(struct sk_buff *skb)
 {
 	return (struct llc_pdu_un *)skb->nh.raw;
 }

 static inline void *llc_set_pdu_hdr(struct sk_buff *skb, void *ptr)
 {
 	return skb->nh.raw = ptr;
 }

 /**
  *	llc_pdu_header_init - initializes pdu header
  *	@skb: input skb that header must be set into it.
  *	@type: type of PDU (U, I or S).
  *	@ssap: source sap.
  *	@dsap: destination sap.
  *	@cr: command/response bit (0 or 1).
  *
  *	This function sets DSAP, SSAP and command/Response bit in LLC header.
  */
 static inline void llc_pdu_header_init(struct sk_buff *skb, u8 type,
 				       u8 ssap, u8 dsap, u8 cr)
 {
 	const int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
 	struct llc_pdu_un *pdu = llc_set_pdu_hdr(skb, skb_push(skb, hlen));
 	pdu->dsap = dsap;
 	pdu->ssap = ssap;
 	pdu->ssap |= cr;
 }

 /**
  *	llc_pdu_decode_sa - extracs source address (MAC) of input frame
  *	@skb: input skb that source address must be extracted from it.
  *	@sa: pointer to source address (6 byte array).
  *
  *	This function extracts source address(MAC) of input frame.
  */
 static inline void llc_pdu_decode_sa(struct sk_buff *skb, u8 *sa)
 {
 	if (skb->protocol == ntohs(ETH_P_802_2))
 		memcpy(sa, eth_hdr(skb)->h_source, ETH_ALEN);
 	else if (skb->protocol == ntohs(ETH_P_TR_802_2)) {
 		memcpy(sa, tr_hdr(skb)->saddr, ETH_ALEN);
 		*sa &= 0x7F;
 	}
 }

 /**
  *	llc_pdu_decode_da - extracts dest address of input frame
  *	@skb: input skb that destination address must be extracted from it
  *	@sa: pointer to destination address (6 byte array).
  *
  *	This function extracts destination address(MAC) of input frame.
  */
 static inline void llc_pdu_decode_da(struct sk_buff *skb, u8 *da)
 {
 	if (skb->protocol == ntohs(ETH_P_802_2))
 		memcpy(da, eth_hdr(skb)->h_dest, ETH_ALEN);
 	else if (skb->protocol == ntohs(ETH_P_TR_802_2))
 		memcpy(da, tr_hdr(skb)->daddr, ETH_ALEN);
 }

 /**
  *	llc_pdu_decode_ssap - extracts source SAP of input frame
  *	@skb: input skb that source SAP must be extracted from it.
  *	@ssap: source SAP (output argument).
  *
  *	This function extracts source SAP of input frame. Right bit of SSAP is
  *	command/response bit.
  */
 static inline void llc_pdu_decode_ssap(struct sk_buff *skb, u8 *ssap)
 {
 	*ssap = llc_pdu_un_hdr(skb)->ssap & 0xFE;
 }

 /**
  *	llc_pdu_decode_dsap - extracts dest SAP of input frame
  *	@skb: input skb that destination SAP must be extracted from it.
  *	@dsap: destination SAP (output argument).
  *
  *	This function extracts destination SAP of input frame. right bit of
  *	DSAP designates individual/group SAP.
  */
 static inline void llc_pdu_decode_dsap(struct sk_buff *skb, u8 *dsap)
 {
 	*dsap = llc_pdu_un_hdr(skb)->dsap & 0xFE;
 }

 /**
  *	llc_pdu_init_as_ui_cmd - sets LLC header as UI PDU
  *	@skb: input skb that header must be set into it.
  *
  *	This function sets third byte of LLC header as a UI PDU.
  */
 static inline void llc_pdu_init_as_ui_cmd(struct sk_buff *skb)
 {
 	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

 	pdu->ctrl_1  = LLC_PDU_TYPE_U;
 	pdu->ctrl_1 |= LLC_1_PDU_CMD_UI;
 }

 /**
  *	llc_pdu_init_as_test_cmd - sets PDU as TEST
  *	@skb - Address of the skb to build
  *
  * 	Sets a PDU as TEST
  */
 static inline void llc_pdu_init_as_test_cmd(struct sk_buff *skb)
 {
 	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

 	pdu->ctrl_1  = LLC_PDU_TYPE_U;
 	pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
 	pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
 }

 /**
  *	llc_pdu_init_as_test_rsp - build TEST response PDU
  *	@skb: Address of the skb to build
  *	@ev_skb: The received TEST command PDU frame
  *
  *	Builds a pdu frame as a TEST response.
  */
 static inline void llc_pdu_init_as_test_rsp(struct sk_buff *skb,
 					    struct sk_buff *ev_skb)
 {
 	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

 	pdu->ctrl_1  = LLC_PDU_TYPE_U;
 	pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
 	pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
 	if (ev_skb->protocol == ntohs(ETH_P_802_2)) {
 		struct llc_pdu_un *ev_pdu = llc_pdu_un_hdr(ev_skb);
 		int dsize;

 		dsize = ntohs(eth_hdr(ev_skb)->h_proto) - 3;
 		memcpy(((u8 *)pdu) + 3, ((u8 *)ev_pdu) + 3, dsize);
 		skb_put(skb, dsize);
 	}
 }

 /* LLC Type 1 XID command/response information fields format */
 struct llc_xid_info {
 	u8 fmt_id;	/* always 0x81 for LLC */
 	u8 type;	/* different if NULL/non-NULL LSAP */
 	u8 rw;		/* sender receive window */
 };

 /**
  *	llc_pdu_init_as_xid_cmd - sets bytes 3, 4 & 5 of LLC header as XID
  *	@skb: input skb that header must be set into it.
  *
  *	This function sets third,fourth,fifth and sixth bytes of LLC header as
  *	a XID PDU.
  */
 static inline void llc_pdu_init_as_xid_cmd(struct sk_buff *skb,
 					   u8 svcs_supported, u8 rx_window)
 {
 	struct llc_xid_info *xid_info;
 	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

 	pdu->ctrl_1	 = LLC_PDU_TYPE_U;
 	pdu->ctrl_1	|= LLC_1_PDU_CMD_XID;
 	pdu->ctrl_1	|= LLC_U_PF_BIT_MASK;
 	xid_info	 = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
 	xid_info->fmt_id = LLC_XID_FMT_ID;	/* 0x81 */
 	xid_info->type	 = svcs_supported;
 	xid_info->rw	 = rx_window << 1;	/* size of receive window */
 	skb_put(skb, 3);
 }

 /**
  *	llc_pdu_init_as_xid_rsp - builds XID response PDU
  *	@skb: Address of the skb to build
  *	@svcs_supported: The class of the LLC (I or II)
  *	@rx_window: The size of the receive window of the LLC
  *
  *	Builds a pdu frame as an XID response.
  */
 static inline void llc_pdu_init_as_xid_rsp(struct sk_buff *skb,
 					   u8 svcs_supported, u8 rx_window)
 {
 	struct llc_xid_info *xid_info;
 	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

 	pdu->ctrl_1	 = LLC_PDU_TYPE_U;
 	pdu->ctrl_1	|= LLC_1_PDU_CMD_XID;
 	pdu->ctrl_1	|= LLC_U_PF_BIT_MASK;

 	xid_info	 = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
 	xid_info->fmt_id = LLC_XID_FMT_ID;
 	xid_info->type	 = svcs_supported;
 	xid_info->rw	 = rx_window << 1;
 	skb_put(skb, 3);
 }

 /* LLC Type 2 FRMR response information field format */
 struct llc_frmr_info {
 	u16 rej_pdu_ctrl;	/* bits 1-8 if U-PDU */
 	u8  curr_ssv;		/* current send state variable val */
 	u8  curr_rsv;		/* current receive state variable */
 	u8  ind_bits;		/* indicator bits set with macro */
 };

 extern void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 type);
 extern void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value);
 extern void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit);
 extern void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit);
 extern void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr);
 extern void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 extern void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 extern void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 extern void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit);
 extern void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit);
 extern void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb,
 				     struct llc_pdu_sn *prev_pdu,
 				     u8 f_bit, u8 vs, u8 vr, u8 vzyxw);
 extern void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 extern void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 extern void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 extern void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit);
 #endif /* LLC_PDU_H */
	#ifndef LLC_PDU_H
	#define LLC_PDU_H
	/*
	* Copyright (c) 1997 by Procom Technology,Inc.
	* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
	*
	* This program can be redistributed or modified under the terms of the
	* GNU General Public License as published by the Free Software Foundation.
	* This program is distributed without any warranty or implied warranty
	* of merchantability or fitness for a particular purpose.
	*
	* See the GNU General Public License for more details.
	*/

	#include <linux/if_ether.h>
	#include <linux/if_tr.h>

	/* Lengths of frame formats */
	#define LLC_PDU_LEN_I 4 /* header and 2 control bytes */
	#define LLC_PDU_LEN_S 4
	#define LLC_PDU_LEN_U 3 /* header and 1 control byte */
	/* Known SAP addresses */
	#define LLC_GLOBAL_SAP 0xFF
	#define LLC_NULL_SAP 0x00 /* not network-layer visible */
	#define LLC_MGMT_INDIV 0x02 /* station LLC mgmt indiv addr */
	#define LLC_MGMT_GRP 0x03 /* station LLC mgmt group addr */
	#define LLC_RDE_SAP 0xA6 /* route ... */

	/* SAP field bit masks */
	#define LLC_ISO_RESERVED_SAP 0x02
	#define LLC_SAP_GROUP_DSAP 0x01
	#define LLC_SAP_RESP_SSAP 0x01

	/* Group/individual DSAP indicator is DSAP field */
	#define LLC_PDU_GROUP_DSAP_MASK 0x01
	#define LLC_PDU_IS_GROUP_DSAP(pdu) \
	((pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
	#define LLC_PDU_IS_INDIV_DSAP(pdu) \
	(!(pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)

	/* Command/response PDU indicator in SSAP field */
	#define LLC_PDU_CMD_RSP_MASK 0x01
	#define LLC_PDU_CMD 0
	#define LLC_PDU_RSP 1
	#define LLC_PDU_IS_CMD(pdu) ((pdu->ssap & LLC_PDU_RSP) ? 0 : 1)
	#define LLC_PDU_IS_RSP(pdu) ((pdu->ssap & LLC_PDU_RSP) ? 1 : 0)

	/* Get PDU type from 2 lowest-order bits of control field first byte */
	#define LLC_PDU_TYPE_I_MASK 0x01 /* 16-bit control field */
	#define LLC_PDU_TYPE_S_MASK 0x03
	#define LLC_PDU_TYPE_U_MASK 0x03 /* 8-bit control field */
	#define LLC_PDU_TYPE_MASK 0x03

	#define LLC_PDU_TYPE_I 0 /* first bit */
	#define LLC_PDU_TYPE_S 1 /* first two bits */
	#define LLC_PDU_TYPE_U 3 /* first two bits */

	#define LLC_PDU_TYPE_IS_I(pdu) \
	((!(pdu->ctrl_1 & LLC_PDU_TYPE_I_MASK)) ? 1 : 0)

	#define LLC_PDU_TYPE_IS_U(pdu) \
	(((pdu->ctrl_1 & LLC_PDU_TYPE_U_MASK) == LLC_PDU_TYPE_U) ? 1 : 0)

	#define LLC_PDU_TYPE_IS_S(pdu) \
	(((pdu->ctrl_1 & LLC_PDU_TYPE_S_MASK) == LLC_PDU_TYPE_S) ? 1 : 0)

	/* U-format PDU control field masks */
	#define LLC_U_PF_BIT_MASK 0x10 /* P/F bit mask */
	#define LLC_U_PF_IS_1(pdu) ((pdu->ctrl_1 & LLC_U_PF_BIT_MASK) ? 1 : 0)
	#define LLC_U_PF_IS_0(pdu) ((!(pdu->ctrl_1 & LLC_U_PF_BIT_MASK)) ? 1 : 0)

	#define LLC_U_PDU_CMD_MASK 0xEC /* cmd/rsp mask */
	#define LLC_U_PDU_CMD(pdu) (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
	#define LLC_U_PDU_RSP(pdu) (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)

	#define LLC_1_PDU_CMD_UI 0x00 /* Type 1 cmds/rsps */
	#define LLC_1_PDU_CMD_XID 0xAC
	#define LLC_1_PDU_CMD_TEST 0xE0

	#define LLC_2_PDU_CMD_SABME 0x6C /* Type 2 cmds/rsps */
	#define LLC_2_PDU_CMD_DISC 0x40
	#define LLC_2_PDU_RSP_UA 0x60
	#define LLC_2_PDU_RSP_DM 0x0C
	#define LLC_2_PDU_RSP_FRMR 0x84

	/* Type 1 operations */

	/* XID information field bit masks */

	/* LLC format identifier (byte 1) */
	#define LLC_XID_FMT_ID 0x81 /* first byte must be this */

	/* LLC types/classes identifier (byte 2) */
	#define LLC_XID_CLASS_ZEROS_MASK 0xE0 /* these must be zeros */
	#define LLC_XID_CLASS_MASK 0x1F /* AND with byte to get below */

	#define LLC_XID_NULL_CLASS_1 0x01 /* if NULL LSAP...use these */
	#define LLC_XID_NULL_CLASS_2 0x03
	#define LLC_XID_NULL_CLASS_3 0x05
	#define LLC_XID_NULL_CLASS_4 0x07

	#define LLC_XID_NNULL_TYPE_1 0x01 /* if non-NULL LSAP...use these */
	#define LLC_XID_NNULL_TYPE_2 0x02
	#define LLC_XID_NNULL_TYPE_3 0x04
	#define LLC_XID_NNULL_TYPE_1_2 0x03
	#define LLC_XID_NNULL_TYPE_1_3 0x05
	#define LLC_XID_NNULL_TYPE_2_3 0x06
	#define LLC_XID_NNULL_ALL 0x07

	/* Sender Receive Window (byte 3) */
	#define LLC_XID_RW_MASK 0xFE /* AND with value to get below */

	#define LLC_XID_MIN_RW 0x02 /* lowest-order bit always zero */

	/* Type 2 operations */

	#define LLC_2_SEQ_NBR_MODULO ((u8) 128)

	/* I-PDU masks ('ctrl' is I-PDU control word) */
	#define LLC_I_GET_NS(pdu) (u8)((pdu->ctrl_1 & 0xFE) >> 1)
	#define LLC_I_GET_NR(pdu) (u8)((pdu->ctrl_2 & 0xFE) >> 1)

	#define LLC_I_PF_BIT_MASK 0x01

	#define LLC_I_PF_IS_0(pdu) ((!(pdu->ctrl_2 & LLC_I_PF_BIT_MASK)) ? 1 : 0)
	#define LLC_I_PF_IS_1(pdu) ((pdu->ctrl_2 & LLC_I_PF_BIT_MASK) ? 1 : 0)

	/* S-PDU supervisory commands and responses */

	#define LLC_S_PDU_CMD_MASK 0x0C
	#define LLC_S_PDU_CMD(pdu) (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
	#define LLC_S_PDU_RSP(pdu) (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)

	#define LLC_2_PDU_CMD_RR 0x00 /* rx ready cmd */
	#define LLC_2_PDU_RSP_RR 0x00 /* rx ready rsp */
	#define LLC_2_PDU_CMD_REJ 0x08 /* reject PDU cmd */
	#define LLC_2_PDU_RSP_REJ 0x08 /* reject PDU rsp */
	#define LLC_2_PDU_CMD_RNR 0x04 /* rx not ready cmd */
	#define LLC_2_PDU_RSP_RNR 0x04 /* rx not ready rsp */

	#define LLC_S_PF_BIT_MASK 0x01
	#define LLC_S_PF_IS_0(pdu) ((!(pdu->ctrl_2 & LLC_S_PF_BIT_MASK)) ? 1 : 0)
	#define LLC_S_PF_IS_1(pdu) ((pdu->ctrl_2 & LLC_S_PF_BIT_MASK) ? 1 : 0)

	#define PDU_SUPV_GET_Nr(pdu) ((pdu->ctrl_2 & 0xFE) >> 1)
	#define PDU_GET_NEXT_Vr(sn) (++sn & ~LLC_2_SEQ_NBR_MODULO)

	/* FRMR information field macros */

	#define FRMR_INFO_LENGTH 5 /* 5 bytes of information */

	/*
	* info is pointer to FRMR info field structure; 'rej_ctrl' is byte pointer
	* (if U-PDU) or word pointer to rejected PDU control field
	*/
	#define FRMR_INFO_SET_REJ_CNTRL(info,rej_ctrl) \
	info->rej_pdu_ctrl = ((((u8 ) rej_ctrl) & \
	LLC_PDU_TYPE_U) != LLC_PDU_TYPE_U ? \
	(u16)((u16 ) rej_ctrl) : \
	(((u16) ((u8 ) rej_ctrl)) & 0x00FF))

	/*
	* Info is pointer to FRMR info field structure; 'vs' is a byte containing
	* send state variable value in low-order 7 bits (insure the lowest-order
	* bit remains zero (0))
	*/
	#define FRMR_INFO_SET_Vs(info,vs) (info->curr_ssv = (((u8) vs) << 1))
	#define FRMR_INFO_SET_Vr(info,vr) (info->curr_rsv = (((u8) vr) << 1))

	/*
	* Info is pointer to FRMR info field structure; 'cr' is a byte containing
	* the C/R bit value in the low-order bit
	*/
	#define FRMR_INFO_SET_C_R_BIT(info, cr) (info->curr_rsv \|= (((u8) cr) & 0x01))

	/*
	* In the remaining five macros, 'info' is pointer to FRMR info field
	* structure; 'ind' is a byte containing the bit value to set in the
	* lowest-order bit)
	*/
	#define FRMR_INFO_SET_INVALID_PDU_CTRL_IND(info, ind) \
	(info->ind_bits = ((info->ind_bits & 0xFE) \| (((u8) ind) & 0x01)))

	#define FRMR_INFO_SET_INVALID_PDU_INFO_IND(info, ind) \
	(info->ind_bits = ( (info->ind_bits & 0xFD) \| (((u8) ind) & 0x02)))

	#define FRMR_INFO_SET_PDU_INFO_2LONG_IND(info, ind) \
	(info->ind_bits = ( (info->ind_bits & 0xFB) \| (((u8) ind) & 0x04)))

	#define FRMR_INFO_SET_PDU_INVALID_Nr_IND(info, ind) \
	(info->ind_bits = ( (info->ind_bits & 0xF7) \| (((u8) ind) & 0x08)))

	#define FRMR_INFO_SET_PDU_INVALID_Ns_IND(info, ind) \
	(info->ind_bits = ( (info->ind_bits & 0xEF) \| (((u8) ind) & 0x10)))

	/* Sequence-numbered PDU format (4 bytes in length) */
	struct llc_pdu_sn {
	u8 dsap;
	u8 ssap;
	u8 ctrl_1;
	u8 ctrl_2;
	};

	static inline struct llc_pdu_sn llc_pdu_sn_hdr(struct sk_buff skb)
	{
	return (struct llc_pdu_sn *)skb->nh.raw;
	}

	/* Un-numbered PDU format (3 bytes in length) */
	struct llc_pdu_un {
	u8 dsap;
	u8 ssap;
	u8 ctrl_1;
	};

	static inline struct llc_pdu_un llc_pdu_un_hdr(struct sk_buff skb)
	{
	return (struct llc_pdu_un *)skb->nh.raw;
	}

	static inline void llc_set_pdu_hdr(struct sk_buff skb, void *ptr)
	{
	return skb->nh.raw = ptr;
	}

	/**
	* llc_pdu_header_init - initializes pdu header
	* @skb: input skb that header must be set into it.
	* @type: type of PDU (U, I or S).
	* @ssap: source sap.
	* @dsap: destination sap.
	* @cr: command/response bit (0 or 1).
	*
	* This function sets DSAP, SSAP and command/Response bit in LLC header.
	*/
	static inline void llc_pdu_header_init(struct sk_buff *skb, u8 type,
	u8 ssap, u8 dsap, u8 cr)
	{
	const int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
	struct llc_pdu_un *pdu = llc_set_pdu_hdr(skb, skb_push(skb, hlen));
	pdu->dsap = dsap;
	pdu->ssap = ssap;
	pdu->ssap \|= cr;
	}

	/**
	* llc_pdu_decode_sa - extracs source address (MAC) of input frame
	* @skb: input skb that source address must be extracted from it.
	* @sa: pointer to source address (6 byte array).
	*
	* This function extracts source address(MAC) of input frame.
	*/
	static inline void llc_pdu_decode_sa(struct sk_buff skb, u8 sa)
	{
	if (skb->protocol == ntohs(ETH_P_802_2))
	memcpy(sa, eth_hdr(skb)->h_source, ETH_ALEN);
	else if (skb->protocol == ntohs(ETH_P_TR_802_2)) {
	memcpy(sa, tr_hdr(skb)->saddr, ETH_ALEN);
	*sa &= 0x7F;
	}
	}

	/**
	* llc_pdu_decode_da - extracts dest address of input frame
	* @skb: input skb that destination address must be extracted from it
	* @sa: pointer to destination address (6 byte array).
	*
	* This function extracts destination address(MAC) of input frame.
	*/
	static inline void llc_pdu_decode_da(struct sk_buff skb, u8 da)
	{
	if (skb->protocol == ntohs(ETH_P_802_2))
	memcpy(da, eth_hdr(skb)->h_dest, ETH_ALEN);
	else if (skb->protocol == ntohs(ETH_P_TR_802_2))
	memcpy(da, tr_hdr(skb)->daddr, ETH_ALEN);
	}

	/**
	* llc_pdu_decode_ssap - extracts source SAP of input frame
	* @skb: input skb that source SAP must be extracted from it.
	* @ssap: source SAP (output argument).
	*
	* This function extracts source SAP of input frame. Right bit of SSAP is
	* command/response bit.
	*/
	static inline void llc_pdu_decode_ssap(struct sk_buff skb, u8 ssap)
	{
	*ssap = llc_pdu_un_hdr(skb)->ssap & 0xFE;
	}

	/**
	* llc_pdu_decode_dsap - extracts dest SAP of input frame
	* @skb: input skb that destination SAP must be extracted from it.
	* @dsap: destination SAP (output argument).
	*
	* This function extracts destination SAP of input frame. right bit of
	* DSAP designates individual/group SAP.
	*/
	static inline void llc_pdu_decode_dsap(struct sk_buff skb, u8 dsap)
	{
	*dsap = llc_pdu_un_hdr(skb)->dsap & 0xFE;
	}

	/**
	* llc_pdu_init_as_ui_cmd - sets LLC header as UI PDU
	* @skb: input skb that header must be set into it.
	*
	* This function sets third byte of LLC header as a UI PDU.
	*/
	static inline void llc_pdu_init_as_ui_cmd(struct sk_buff *skb)
	{
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	pdu->ctrl_1 = LLC_PDU_TYPE_U;
	pdu->ctrl_1 \|= LLC_1_PDU_CMD_UI;
	}

	/**
	* llc_pdu_init_as_test_cmd - sets PDU as TEST
	* @skb - Address of the skb to build
	*
	* Sets a PDU as TEST
	*/
	static inline void llc_pdu_init_as_test_cmd(struct sk_buff *skb)
	{
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	pdu->ctrl_1 = LLC_PDU_TYPE_U;
	pdu->ctrl_1 \|= LLC_1_PDU_CMD_TEST;
	pdu->ctrl_1 \|= LLC_U_PF_BIT_MASK;
	}

	/**
	* llc_pdu_init_as_test_rsp - build TEST response PDU
	* @skb: Address of the skb to build
	* @ev_skb: The received TEST command PDU frame
	*
	* Builds a pdu frame as a TEST response.
	*/
	static inline void llc_pdu_init_as_test_rsp(struct sk_buff *skb,
	struct sk_buff *ev_skb)
	{
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	pdu->ctrl_1 = LLC_PDU_TYPE_U;
	pdu->ctrl_1 \|= LLC_1_PDU_CMD_TEST;
	pdu->ctrl_1 \|= LLC_U_PF_BIT_MASK;
	if (ev_skb->protocol == ntohs(ETH_P_802_2)) {
	struct llc_pdu_un *ev_pdu = llc_pdu_un_hdr(ev_skb);
	int dsize;

	dsize = ntohs(eth_hdr(ev_skb)->h_proto) - 3;
	memcpy(((u8 )pdu) + 3, ((u8 )ev_pdu) + 3, dsize);
	skb_put(skb, dsize);
	}
	}

	/* LLC Type 1 XID command/response information fields format */
	struct llc_xid_info {
	u8 fmt_id; /* always 0x81 for LLC */
	u8 type; /* different if NULL/non-NULL LSAP */
	u8 rw; /* sender receive window */
	};

	/**
	* llc_pdu_init_as_xid_cmd - sets bytes 3, 4 & 5 of LLC header as XID
	* @skb: input skb that header must be set into it.
	*
	* This function sets third,fourth,fifth and sixth bytes of LLC header as
	* a XID PDU.
	*/
	static inline void llc_pdu_init_as_xid_cmd(struct sk_buff *skb,
	u8 svcs_supported, u8 rx_window)
	{
	struct llc_xid_info *xid_info;
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	pdu->ctrl_1 = LLC_PDU_TYPE_U;
	pdu->ctrl_1 \|= LLC_1_PDU_CMD_XID;
	pdu->ctrl_1 \|= LLC_U_PF_BIT_MASK;
	xid_info = (struct llc_xid_info )(((u8 )&pdu->ctrl_1) + 1);
	xid_info->fmt_id = LLC_XID_FMT_ID; /* 0x81 */
	xid_info->type = svcs_supported;
	xid_info->rw = rx_window << 1; /* size of receive window */
	skb_put(skb, 3);
	}

	/**
	* llc_pdu_init_as_xid_rsp - builds XID response PDU
	* @skb: Address of the skb to build
	* @svcs_supported: The class of the LLC (I or II)
	* @rx_window: The size of the receive window of the LLC
	*
	* Builds a pdu frame as an XID response.
	*/
	static inline void llc_pdu_init_as_xid_rsp(struct sk_buff *skb,
	u8 svcs_supported, u8 rx_window)
	{
	struct llc_xid_info *xid_info;
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	pdu->ctrl_1 = LLC_PDU_TYPE_U;
	pdu->ctrl_1 \|= LLC_1_PDU_CMD_XID;
	pdu->ctrl_1 \|= LLC_U_PF_BIT_MASK;

	xid_info = (struct llc_xid_info )(((u8 )&pdu->ctrl_1) + 1);
	xid_info->fmt_id = LLC_XID_FMT_ID;
	xid_info->type = svcs_supported;
	xid_info->rw = rx_window << 1;
	skb_put(skb, 3);
	}

	/* LLC Type 2 FRMR response information field format */
	struct llc_frmr_info {
	u16 rej_pdu_ctrl; /* bits 1-8 if U-PDU */
	u8 curr_ssv; /* current send state variable val */
	u8 curr_rsv; /* current receive state variable */
	u8 ind_bits; /* indicator bits set with macro */
	};

	extern void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 type);
	extern void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value);
	extern void llc_pdu_decode_pf_bit(struct sk_buff skb, u8 pf_bit);
	extern void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit);
	extern void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr);
	extern void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
	extern void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
	extern void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
	extern void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit);
	extern void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit);
	extern void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb,
	struct llc_pdu_sn *prev_pdu,
	u8 f_bit, u8 vs, u8 vr, u8 vzyxw);
	extern void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
	extern void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
	extern void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
	extern void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit);
	#endif /* LLC_PDU_H */