llc_pdu.c

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/*
 * 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;
}

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;
    }
}

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;
    }
}

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;
}

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 */
}

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 */
}

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 */
}

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 */
}

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;
}

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;
}

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));
}

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 */
}

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 */
}

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 */
}

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;
}

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;
}

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;
}