[linux.git] / net / llc / llc_pdu.c

/*
 * llc_pdu.c - access to PDU internals
 *
 * Copyright (c) 1997 by Procom Technology, Inc.
 *		 2001-2003 by Arnaldo Carvalho de Melo <[email protected]>
 *
 * 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/netdevice.h>
#include <net/llc_pdu.h>

static void llc_pdu_decode_pdu_type(struct sk_buff *skb, u8 *type);
static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu);

void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 pdu_type)
{
	llc_pdu_un_hdr(skb)->ssap |= pdu_type;
}

/**
 *	pdu_set_pf_bit - sets poll/final bit in LLC header
 *	@pdu_frame: input frame that p/f bit must be set into it.
 *	@bit_value: poll/final bit (0 or 1).
 *
 *	This function sets poll/final bit in LLC header (based on type of PDU).
 *	in I or S pdus, p/f bit is right bit of fourth byte in header. in U
 *	pdus p/f bit is fifth bit of third byte.
 */
void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value)
{
	u8 pdu_type;
	struct llc_pdu_sn *pdu;

	llc_pdu_decode_pdu_type(skb, &pdu_type);
	pdu = llc_pdu_sn_hdr(skb);
	
	switch (pdu_type) {
	case LLC_PDU_TYPE_I:
	case LLC_PDU_TYPE_S:
		pdu->ctrl_2 = (pdu->ctrl_2 & 0xFE) | bit_value;
		break;
	case LLC_PDU_TYPE_U:
		pdu->ctrl_1 |= (pdu->ctrl_1 & 0xEF) | (bit_value << 4);
		break;
	}
}

/**
 *	llc_pdu_decode_pf_bit - extracs poll/final bit from LLC header
 *	@skb: input skb that p/f bit must be extracted from it
 *	@pf_bit: poll/final bit (0 or 1)
 *
 *	This function extracts poll/final bit from LLC header (based on type of
 *	PDU). In I or S pdus, p/f bit is right bit of fourth byte in header. In
 *	U pdus p/f bit is fifth bit of third byte.
 */
void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit)
{
	u8 pdu_type;
	struct llc_pdu_sn *pdu;

	llc_pdu_decode_pdu_type(skb, &pdu_type);
	pdu = llc_pdu_sn_hdr(skb);

	switch (pdu_type) {
	case LLC_PDU_TYPE_I:
	case LLC_PDU_TYPE_S:
		*pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK;
		break;
	case LLC_PDU_TYPE_U:
		*pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4;
		break;
	}
}

/**
 *	llc_pdu_init_as_disc_cmd - Builds DISC PDU
 *	@skb: Address of the skb to build
 *	@p_bit: The P bit to set in the PDU
 *
 *	Builds a pdu frame as a DISC command.
 */
void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit)
{
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_U;
	pdu->ctrl_1 |= LLC_2_PDU_CMD_DISC;
	pdu->ctrl_1 |= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
}

/**
 *	llc_pdu_init_as_i_cmd - builds I pdu
 *	@skb: Address of the skb to build
 *	@p_bit: The P bit to set in the PDU
 *	@ns: The sequence number of the data PDU
 *	@nr: The seq. number of the expected I PDU from the remote
 *
 *	Builds a pdu frame as an I command.
 */
void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr)
{
	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_I;
	pdu->ctrl_2  = 0;
	pdu->ctrl_2 |= (p_bit & LLC_I_PF_BIT_MASK); /* p/f bit */
	pdu->ctrl_1 |= (ns << 1) & 0xFE;   /* set N(S) in bits 2..8 */
	pdu->ctrl_2 |= (nr << 1) & 0xFE;   /* set N(R) in bits 10..16 */
}

/**
 *	llc_pdu_init_as_rej_cmd - builds REJ PDU
 *	@skb: Address of the skb to build
 *	@p_bit: The P bit to set in the PDU
 *	@nr: The seq. number of the expected I PDU from the remote
 *
 *	Builds a pdu frame as a REJ command.
 */
void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
{
	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_S;
	pdu->ctrl_1 |= LLC_2_PDU_CMD_REJ;
	pdu->ctrl_2  = 0;
	pdu->ctrl_2 |= p_bit & LLC_S_PF_BIT_MASK;
	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
	pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}

/**
 *	llc_pdu_init_as_rnr_cmd - builds RNR pdu
 *	@skb: Address of the skb to build
 *	@p_bit: The P bit to set in the PDU
 *	@nr: The seq. number of the expected I PDU from the remote
 *
 *	Builds a pdu frame as an RNR command.
 */
void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
{
	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_S;
	pdu->ctrl_1 |= LLC_2_PDU_CMD_RNR;
	pdu->ctrl_2  = 0;
	pdu->ctrl_2 |= p_bit & LLC_S_PF_BIT_MASK;
	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
	pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}

/**
 *	llc_pdu_init_as_rr_cmd - Builds RR pdu
 *	@skb: Address of the skb to build
 *	@p_bit: The P bit to set in the PDU
 *	@nr: The seq. number of the expected I PDU from the remote
 *
 *	Builds a pdu frame as an RR command.
 */
void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
{
	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_S;
	pdu->ctrl_1 |= LLC_2_PDU_CMD_RR;
	pdu->ctrl_2  = p_bit & LLC_S_PF_BIT_MASK;
	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
	pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
}

/**
 *	llc_pdu_init_as_sabme_cmd - builds SABME pdu
 *	@skb: Address of the skb to build
 *	@p_bit: The P bit to set in the PDU
 *
 *	Builds a pdu frame as an SABME command.
 */
void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit)
{
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_U;
	pdu->ctrl_1 |= LLC_2_PDU_CMD_SABME;
	pdu->ctrl_1 |= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
}

/**
 *	llc_pdu_init_as_dm_rsp - builds DM response pdu
 *	@skb: Address of the skb to build
 *	@f_bit: The F bit to set in the PDU
 *
 *	Builds a pdu frame as a DM response.
 */
void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit)
{
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_U;
	pdu->ctrl_1 |= LLC_2_PDU_RSP_DM;
	pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
}

/**
 *	llc_pdu_init_as_frmr_rsp - builds FRMR response PDU
 *	@skb: Address of the frame to build
 *	@prev_pdu: The rejected PDU frame
 *	@f_bit: The F bit to set in the PDU
 *	@vs: tx state vari value for the data link conn at the rejecting LLC
 *	@vr: rx state var value for the data link conn at the rejecting LLC
 *	@vzyxw: completely described in the IEEE Std 802.2 document (Pg 55)
 *
 *	Builds a pdu frame as a FRMR response.
 */
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)
{
	struct llc_frmr_info *frmr_info;
	u8 prev_pf = 0;
	u8 *ctrl;
	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_U;
	pdu->ctrl_1 |= LLC_2_PDU_RSP_FRMR;
	pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;

	frmr_info = (struct llc_frmr_info *)&pdu->ctrl_2;
	ctrl = (u8 *)&prev_pdu->ctrl_1;
	FRMR_INFO_SET_REJ_CNTRL(frmr_info,ctrl);
	FRMR_INFO_SET_Vs(frmr_info, vs);
	FRMR_INFO_SET_Vr(frmr_info, vr);
	prev_pf = llc_pdu_get_pf_bit(prev_pdu);
	FRMR_INFO_SET_C_R_BIT(frmr_info, prev_pf);
	FRMR_INFO_SET_INVALID_PDU_CTRL_IND(frmr_info, vzyxw);
	FRMR_INFO_SET_INVALID_PDU_INFO_IND(frmr_info, vzyxw);
	FRMR_INFO_SET_PDU_INFO_2LONG_IND(frmr_info, vzyxw);
	FRMR_INFO_SET_PDU_INVALID_Nr_IND(frmr_info, vzyxw);
	FRMR_INFO_SET_PDU_INVALID_Ns_IND(frmr_info, vzyxw);
	skb_put(skb, 5);
}

/**
 *	llc_pdu_init_as_rr_rsp - builds RR response pdu
 *	@skb: Address of the skb to build
 *	@f_bit: The F bit to set in the PDU
 *	@nr: The seq. number of the expected data PDU from the remote
 *
 *	Builds a pdu frame as an RR response.
 */
void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
{
	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_S;
	pdu->ctrl_1 |= LLC_2_PDU_RSP_RR;
	pdu->ctrl_2  = 0;
	pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK;
	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
	pdu->ctrl_2 |= (nr << 1) & 0xFE;  /* set N(R) in bits 10..16 */
}

/**
 *	llc_pdu_init_as_rej_rsp - builds REJ response pdu
 *	@skb: Address of the skb to build
 *	@f_bit: The F bit to set in the PDU
 *	@nr: The seq. number of the expected data PDU from the remote
 *
 *	Builds a pdu frame as a REJ response.
 */
void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
{
	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_S;
	pdu->ctrl_1 |= LLC_2_PDU_RSP_REJ;
	pdu->ctrl_2  = 0;
	pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK;
	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
	pdu->ctrl_2 |= (nr << 1) & 0xFE;  /* set N(R) in bits 10..16 */
}

/**
 *	llc_pdu_init_as_rnr_rsp - builds RNR response pdu
 *	@skb: Address of the frame to build
 *	@f_bit: The F bit to set in the PDU
 *	@nr: The seq. number of the expected data PDU from the remote
 *
 *	Builds a pdu frame as an RNR response.
 */
void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
{
	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_S;
	pdu->ctrl_1 |= LLC_2_PDU_RSP_RNR;
	pdu->ctrl_2  = 0;
	pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK;
	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
	pdu->ctrl_2 |= (nr << 1) & 0xFE;  /* set N(R) in bits 10..16 */
}

/**
 *	llc_pdu_init_as_ua_rsp - builds UA response pdu
 *	@skb: Address of the frame to build
 *	@f_bit: The F bit to set in the PDU
 *
 *	Builds a pdu frame as a UA response.
 */
void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit)
{
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	pdu->ctrl_1  = LLC_PDU_TYPE_U;
	pdu->ctrl_1 |= LLC_2_PDU_RSP_UA;
	pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
}

/**
 *	llc_pdu_decode_pdu_type - designates PDU type
 *	@skb: input skb that type of it must be designated.
 *	@type: type of PDU (output argument).
 *
 *	This function designates type of PDU (I, S or U).
 */
static void llc_pdu_decode_pdu_type(struct sk_buff *skb, u8 *type)
{
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	if (pdu->ctrl_1 & 1) {
		if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U)
			*type = LLC_PDU_TYPE_U;
		else
			*type = LLC_PDU_TYPE_S;
	} else
		*type = LLC_PDU_TYPE_I;
}

/**
 *	llc_pdu_get_pf_bit - extracts p/f bit of input PDU
 *	@pdu: pointer to LLC header.
 *
 *	This function extracts p/f bit of input PDU. at first examines type of
 *	PDU and then extracts p/f bit. Returns the p/f bit.
 */
static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu)
{
	u8 pdu_type;
	u8 pf_bit = 0;

	if (pdu->ctrl_1 & 1) {
		if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U)
			pdu_type = LLC_PDU_TYPE_U;
		else
			pdu_type = LLC_PDU_TYPE_S;
	} else
		pdu_type = LLC_PDU_TYPE_I;
	switch (pdu_type) {
	case LLC_PDU_TYPE_I:
	case LLC_PDU_TYPE_S:
		pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK;
		break;
	case LLC_PDU_TYPE_U:
		pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4;
		break;
	}
	return pf_bit;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* llc_pdu.c - access to PDU internals
	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/netdevice.h>
	16	#include <net/llc_pdu.h>
	17
	18	static void llc_pdu_decode_pdu_type(struct sk_buff skb, u8 type);
	19	static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu);
	20
	21	void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 pdu_type)
	22	{
	23	llc_pdu_un_hdr(skb)->ssap \|= pdu_type;
	24	}
	25
	26	/**
	27	* pdu_set_pf_bit - sets poll/final bit in LLC header
	28	* @pdu_frame: input frame that p/f bit must be set into it.
	29	* @bit_value: poll/final bit (0 or 1).
	30	*
	31	* This function sets poll/final bit in LLC header (based on type of PDU).
	32	* in I or S pdus, p/f bit is right bit of fourth byte in header. in U
	33	* pdus p/f bit is fifth bit of third byte.
	34	*/
	35	void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value)
	36	{
	37	u8 pdu_type;
	38	struct llc_pdu_sn *pdu;
	39
	40	llc_pdu_decode_pdu_type(skb, &pdu_type);
	41	pdu = llc_pdu_sn_hdr(skb);
	42
	43	switch (pdu_type) {
	44	case LLC_PDU_TYPE_I:
	45	case LLC_PDU_TYPE_S:
	46	pdu->ctrl_2 = (pdu->ctrl_2 & 0xFE) \| bit_value;
	47	break;
	48	case LLC_PDU_TYPE_U:
	49	pdu->ctrl_1 \|= (pdu->ctrl_1 & 0xEF) \| (bit_value << 4);
	50	break;
	51	}
	52	}
	53
	54	/**
	55	* llc_pdu_decode_pf_bit - extracs poll/final bit from LLC header
	56	* @skb: input skb that p/f bit must be extracted from it
	57	* @pf_bit: poll/final bit (0 or 1)
	58	*
	59	* This function extracts poll/final bit from LLC header (based on type of
	60	* PDU). In I or S pdus, p/f bit is right bit of fourth byte in header. In
	61	* U pdus p/f bit is fifth bit of third byte.
	62	*/
	63	void llc_pdu_decode_pf_bit(struct sk_buff skb, u8 pf_bit)
	64	{
65	u8 pdu_type;
66	struct llc_pdu_sn *pdu;
67
68	llc_pdu_decode_pdu_type(skb, &pdu_type);
69	pdu = llc_pdu_sn_hdr(skb);
70
71	switch (pdu_type) {
72	case LLC_PDU_TYPE_I:
73	case LLC_PDU_TYPE_S:
74	*pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK;
75	break;
76	case LLC_PDU_TYPE_U:
77	*pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4;
78	break;
79	}
80	}
81
82	/**
83	* llc_pdu_init_as_disc_cmd - Builds DISC PDU
84	* @skb: Address of the skb to build
85	* @p_bit: The P bit to set in the PDU
86	*
87	* Builds a pdu frame as a DISC command.
88	*/
89	void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit)
90	{
91	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
92
93	pdu->ctrl_1 = LLC_PDU_TYPE_U;
94	pdu->ctrl_1 \|= LLC_2_PDU_CMD_DISC;
95	pdu->ctrl_1 \|= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
96	}
97
98	/**
99	* llc_pdu_init_as_i_cmd - builds I pdu
100	* @skb: Address of the skb to build
101	* @p_bit: The P bit to set in the PDU
102	* @ns: The sequence number of the data PDU
103	* @nr: The seq. number of the expected I PDU from the remote
104	*
105	* Builds a pdu frame as an I command.
106	*/
107	void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr)
108	{
109	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
110
111	pdu->ctrl_1 = LLC_PDU_TYPE_I;
112	pdu->ctrl_2 = 0;
113	pdu->ctrl_2 \|= (p_bit & LLC_I_PF_BIT_MASK); /* p/f bit */
114	pdu->ctrl_1 \|= (ns << 1) & 0xFE; /* set N(S) in bits 2..8 */
115	pdu->ctrl_2 \|= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
116	}
117
118	/**
119	* llc_pdu_init_as_rej_cmd - builds REJ PDU
120	* @skb: Address of the skb to build
121	* @p_bit: The P bit to set in the PDU
122	* @nr: The seq. number of the expected I PDU from the remote
123	*
124	* Builds a pdu frame as a REJ command.
125	*/
126	void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
127	{
128	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
129
130	pdu->ctrl_1 = LLC_PDU_TYPE_S;
131	pdu->ctrl_1 \|= LLC_2_PDU_CMD_REJ;
132	pdu->ctrl_2 = 0;
133	pdu->ctrl_2 \|= p_bit & LLC_S_PF_BIT_MASK;
134	pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
135	pdu->ctrl_2 \|= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
136	}
137
138	/**
139	* llc_pdu_init_as_rnr_cmd - builds RNR pdu
140	* @skb: Address of the skb to build
141	* @p_bit: The P bit to set in the PDU
142	* @nr: The seq. number of the expected I PDU from the remote
143	*
144	* Builds a pdu frame as an RNR command.
145	*/
146	void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
147	{
148	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
149
150	pdu->ctrl_1 = LLC_PDU_TYPE_S;
151	pdu->ctrl_1 \|= LLC_2_PDU_CMD_RNR;
152	pdu->ctrl_2 = 0;
153	pdu->ctrl_2 \|= p_bit & LLC_S_PF_BIT_MASK;
154	pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
155	pdu->ctrl_2 \|= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
156	}
157
158	/**
159	* llc_pdu_init_as_rr_cmd - Builds RR pdu
160	* @skb: Address of the skb to build
161	* @p_bit: The P bit to set in the PDU
162	* @nr: The seq. number of the expected I PDU from the remote
163	*
164	* Builds a pdu frame as an RR command.
165	*/
166	void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
167	{
168	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
169
170	pdu->ctrl_1 = LLC_PDU_TYPE_S;
171	pdu->ctrl_1 \|= LLC_2_PDU_CMD_RR;
172	pdu->ctrl_2 = p_bit & LLC_S_PF_BIT_MASK;
173	pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
174	pdu->ctrl_2 \|= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
175	}
176
177	/**
178	* llc_pdu_init_as_sabme_cmd - builds SABME pdu
179	* @skb: Address of the skb to build
180	* @p_bit: The P bit to set in the PDU
181	*
182	* Builds a pdu frame as an SABME command.
183	*/
184	void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit)
185	{
186	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
187
188	pdu->ctrl_1 = LLC_PDU_TYPE_U;
189	pdu->ctrl_1 \|= LLC_2_PDU_CMD_SABME;
190	pdu->ctrl_1 \|= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
191	}
192
193	/**
194	* llc_pdu_init_as_dm_rsp - builds DM response pdu
195	* @skb: Address of the skb to build
196	* @f_bit: The F bit to set in the PDU
197	*
198	* Builds a pdu frame as a DM response.
199	*/
200	void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit)
201	{
202	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
203
204	pdu->ctrl_1 = LLC_PDU_TYPE_U;
205	pdu->ctrl_1 \|= LLC_2_PDU_RSP_DM;
206	pdu->ctrl_1 \|= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
207	}
208
209	/**
210	* llc_pdu_init_as_frmr_rsp - builds FRMR response PDU
211	* @skb: Address of the frame to build
212	* @prev_pdu: The rejected PDU frame
213	* @f_bit: The F bit to set in the PDU
214	* @vs: tx state vari value for the data link conn at the rejecting LLC
215	* @vr: rx state var value for the data link conn at the rejecting LLC
216	* @vzyxw: completely described in the IEEE Std 802.2 document (Pg 55)
217	*
218	* Builds a pdu frame as a FRMR response.
219	*/
220	void llc_pdu_init_as_frmr_rsp(struct sk_buff skb, struct llc_pdu_sn prev_pdu,
221	u8 f_bit, u8 vs, u8 vr, u8 vzyxw)
222	{
223	struct llc_frmr_info *frmr_info;
224	u8 prev_pf = 0;
225	u8 *ctrl;
226	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
227
228	pdu->ctrl_1 = LLC_PDU_TYPE_U;
229	pdu->ctrl_1 \|= LLC_2_PDU_RSP_FRMR;
230	pdu->ctrl_1 \|= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
231
232	frmr_info = (struct llc_frmr_info *)&pdu->ctrl_2;
233	ctrl = (u8 *)&prev_pdu->ctrl_1;
234	FRMR_INFO_SET_REJ_CNTRL(frmr_info,ctrl);
235	FRMR_INFO_SET_Vs(frmr_info, vs);
236	FRMR_INFO_SET_Vr(frmr_info, vr);
237	prev_pf = llc_pdu_get_pf_bit(prev_pdu);
238	FRMR_INFO_SET_C_R_BIT(frmr_info, prev_pf);
239	FRMR_INFO_SET_INVALID_PDU_CTRL_IND(frmr_info, vzyxw);
240	FRMR_INFO_SET_INVALID_PDU_INFO_IND(frmr_info, vzyxw);
241	FRMR_INFO_SET_PDU_INFO_2LONG_IND(frmr_info, vzyxw);
242	FRMR_INFO_SET_PDU_INVALID_Nr_IND(frmr_info, vzyxw);
243	FRMR_INFO_SET_PDU_INVALID_Ns_IND(frmr_info, vzyxw);
244	skb_put(skb, 5);
245	}
246
247	/**
248	* llc_pdu_init_as_rr_rsp - builds RR response pdu
249	* @skb: Address of the skb to build
250	* @f_bit: The F bit to set in the PDU
251	* @nr: The seq. number of the expected data PDU from the remote
252	*
253	* Builds a pdu frame as an RR response.
254	*/
255	void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
256	{
257	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
258
259	pdu->ctrl_1 = LLC_PDU_TYPE_S;
260	pdu->ctrl_1 \|= LLC_2_PDU_RSP_RR;
261	pdu->ctrl_2 = 0;
262	pdu->ctrl_2 \|= f_bit & LLC_S_PF_BIT_MASK;
263	pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
264	pdu->ctrl_2 \|= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
265	}
266
267	/**
268	* llc_pdu_init_as_rej_rsp - builds REJ response pdu
269	* @skb: Address of the skb to build
270	* @f_bit: The F bit to set in the PDU
271	* @nr: The seq. number of the expected data PDU from the remote
272	*
273	* Builds a pdu frame as a REJ response.
274	*/
275	void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
276	{
277	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
278
279	pdu->ctrl_1 = LLC_PDU_TYPE_S;
280	pdu->ctrl_1 \|= LLC_2_PDU_RSP_REJ;
281	pdu->ctrl_2 = 0;
282	pdu->ctrl_2 \|= f_bit & LLC_S_PF_BIT_MASK;
283	pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
284	pdu->ctrl_2 \|= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
285	}
286
287	/**
288	* llc_pdu_init_as_rnr_rsp - builds RNR response pdu
289	* @skb: Address of the frame to build
290	* @f_bit: The F bit to set in the PDU
291	* @nr: The seq. number of the expected data PDU from the remote
292	*
293	* Builds a pdu frame as an RNR response.
294	*/
295	void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
296	{
297	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
298
299	pdu->ctrl_1 = LLC_PDU_TYPE_S;
300	pdu->ctrl_1 \|= LLC_2_PDU_RSP_RNR;
301	pdu->ctrl_2 = 0;
302	pdu->ctrl_2 \|= f_bit & LLC_S_PF_BIT_MASK;
303	pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */
304	pdu->ctrl_2 \|= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
305	}
306
307	/**
308	* llc_pdu_init_as_ua_rsp - builds UA response pdu
309	* @skb: Address of the frame to build
310	* @f_bit: The F bit to set in the PDU
311	*
312	* Builds a pdu frame as a UA response.
313	*/
314	void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit)
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_2_PDU_RSP_UA;
320	pdu->ctrl_1 \|= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
321	}
322
323	/**
324	* llc_pdu_decode_pdu_type - designates PDU type
325	* @skb: input skb that type of it must be designated.
326	* @type: type of PDU (output argument).
327	*
328	* This function designates type of PDU (I, S or U).
329	*/
330	static void llc_pdu_decode_pdu_type(struct sk_buff skb, u8 type)
331	{
332	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
333
334	if (pdu->ctrl_1 & 1) {
335	if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U)
336	*type = LLC_PDU_TYPE_U;
337	else
338	*type = LLC_PDU_TYPE_S;
339	} else
340	*type = LLC_PDU_TYPE_I;
341	}
342
343	/**
344	* llc_pdu_get_pf_bit - extracts p/f bit of input PDU
345	* @pdu: pointer to LLC header.
346	*
347	* This function extracts p/f bit of input PDU. at first examines type of
348	* PDU and then extracts p/f bit. Returns the p/f bit.
349	*/
350	static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu)
351	{
352	u8 pdu_type;
353	u8 pf_bit = 0;
354
355	if (pdu->ctrl_1 & 1) {
356	if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U)
357	pdu_type = LLC_PDU_TYPE_U;
358	else
359	pdu_type = LLC_PDU_TYPE_S;
360	} else
361	pdu_type = LLC_PDU_TYPE_I;
362	switch (pdu_type) {
363	case LLC_PDU_TYPE_I:
364	case LLC_PDU_TYPE_S:
365	pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK;
366	break;
367	case LLC_PDU_TYPE_U:
368	pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4;
369	break;
370	}
371	return pf_bit;
372	}