llc_pdu.c
/*
* llc_pdu.c - access to PDU internals
*
* 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/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, sizeof(struct llc_frmr_info));
}
/**
* 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;
}
