Merge branch 'for-3.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj...

[zen-stable.git] / net / llc / llc_c_ac.c

/*
 * llc_c_ac.c - actions performed during connection state transition.
 *
 * Description:
 *   Functions in this module are implementation of connection component actions
 *   Details of actions can be found in IEEE-802.2 standard document.
 *   All functions have one connection and one event as input argument. All of
 *   them return 0 On success and 1 otherwise.
 *
 * 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 <linux/slab.h>
#include <net/llc_conn.h>
#include <net/llc_sap.h>
#include <net/sock.h>
#include <net/llc_c_ev.h>
#include <net/llc_c_ac.h>
#include <net/llc_c_st.h>
#include <net/llc_pdu.h>
#include <net/llc.h>


static int llc_conn_ac_inc_vs_by_1(struct sock *sk, struct sk_buff *skb);
static void llc_process_tmr_ev(struct sock *sk, struct sk_buff *skb);
static int llc_conn_ac_data_confirm(struct sock *sk, struct sk_buff *ev);

static int llc_conn_ac_inc_npta_value(struct sock *sk, struct sk_buff *skb);

static int llc_conn_ac_send_rr_rsp_f_set_ackpf(struct sock *sk,
                                               struct sk_buff *skb);

static int llc_conn_ac_set_p_flag_1(struct sock *sk, struct sk_buff *skb);

#define INCORRECT 0

int llc_conn_ac_clear_remote_busy(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        if (llc->remote_busy_flag) {
                u8 nr;
                struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

                llc->remote_busy_flag = 0;
                del_timer(&llc->busy_state_timer.timer);
                nr = LLC_I_GET_NR(pdu);
                llc_conn_resend_i_pdu_as_cmd(sk, nr, 0);
        }
        return 0;
}

int llc_conn_ac_conn_ind(struct sock *sk, struct sk_buff *skb)
{
        struct llc_conn_state_ev *ev = llc_conn_ev(skb);

        ev->ind_prim = LLC_CONN_PRIM;
        return 0;
}

int llc_conn_ac_conn_confirm(struct sock *sk, struct sk_buff *skb)
{
        struct llc_conn_state_ev *ev = llc_conn_ev(skb);

        ev->cfm_prim = LLC_CONN_PRIM;
        return 0;
}

static int llc_conn_ac_data_confirm(struct sock *sk, struct sk_buff *skb)
{
        struct llc_conn_state_ev *ev = llc_conn_ev(skb);

        ev->cfm_prim = LLC_DATA_PRIM;
        return 0;
}

int llc_conn_ac_data_ind(struct sock *sk, struct sk_buff *skb)
{
        llc_conn_rtn_pdu(sk, skb);
        return 0;
}

int llc_conn_ac_disc_ind(struct sock *sk, struct sk_buff *skb)
{
        struct llc_conn_state_ev *ev = llc_conn_ev(skb);
        u8 reason = 0;
        int rc = 0;

        if (ev->type == LLC_CONN_EV_TYPE_PDU) {
                struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

                if (LLC_PDU_IS_RSP(pdu) &&
                    LLC_PDU_TYPE_IS_U(pdu) &&
                    LLC_U_PDU_RSP(pdu) == LLC_2_PDU_RSP_DM)
                        reason = LLC_DISC_REASON_RX_DM_RSP_PDU;
                else if (LLC_PDU_IS_CMD(pdu) &&
                           LLC_PDU_TYPE_IS_U(pdu) &&
                           LLC_U_PDU_CMD(pdu) == LLC_2_PDU_CMD_DISC)
                        reason = LLC_DISC_REASON_RX_DISC_CMD_PDU;
        } else if (ev->type == LLC_CONN_EV_TYPE_ACK_TMR)
                reason = LLC_DISC_REASON_ACK_TMR_EXP;
        else
                rc = -EINVAL;
        if (!rc) {
                ev->reason   = reason;
                ev->ind_prim = LLC_DISC_PRIM;
        }
        return rc;
}

int llc_conn_ac_disc_confirm(struct sock *sk, struct sk_buff *skb)
{
        struct llc_conn_state_ev *ev = llc_conn_ev(skb);

        ev->reason   = ev->status;
        ev->cfm_prim = LLC_DISC_PRIM;
        return 0;
}

int llc_conn_ac_rst_ind(struct sock *sk, struct sk_buff *skb)
{
        u8 reason = 0;
        int rc = 1;
        struct llc_conn_state_ev *ev = llc_conn_ev(skb);
        struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
        struct llc_sock *llc = llc_sk(sk);

        switch (ev->type) {
        case LLC_CONN_EV_TYPE_PDU:
                if (LLC_PDU_IS_RSP(pdu) &&
                    LLC_PDU_TYPE_IS_U(pdu) &&
                    LLC_U_PDU_RSP(pdu) == LLC_2_PDU_RSP_FRMR) {
                        reason = LLC_RESET_REASON_LOCAL;
                        rc = 0;
                } else if (LLC_PDU_IS_CMD(pdu) &&
                           LLC_PDU_TYPE_IS_U(pdu) &&
                           LLC_U_PDU_CMD(pdu) == LLC_2_PDU_CMD_SABME) {
                        reason = LLC_RESET_REASON_REMOTE;
                        rc = 0;
                }
                break;
        case LLC_CONN_EV_TYPE_ACK_TMR:
        case LLC_CONN_EV_TYPE_P_TMR:
        case LLC_CONN_EV_TYPE_REJ_TMR:
        case LLC_CONN_EV_TYPE_BUSY_TMR:
                if (llc->retry_count > llc->n2) {
                        reason = LLC_RESET_REASON_LOCAL;
                        rc = 0;
                }
                break;
        }
        if (!rc) {
                ev->reason   = reason;
                ev->ind_prim = LLC_RESET_PRIM;
        }
        return rc;
}

int llc_conn_ac_rst_confirm(struct sock *sk, struct sk_buff *skb)
{
        struct llc_conn_state_ev *ev = llc_conn_ev(skb);

        ev->reason   = 0;
        ev->cfm_prim = LLC_RESET_PRIM;
        return 0;
}

int llc_conn_ac_clear_remote_busy_if_f_eq_1(struct sock *sk,
                                            struct sk_buff *skb)
{
        struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

        if (LLC_PDU_IS_RSP(pdu) &&
            LLC_PDU_TYPE_IS_I(pdu) &&
            LLC_I_PF_IS_1(pdu) && llc_sk(sk)->ack_pf)
                llc_conn_ac_clear_remote_busy(sk, skb);
        return 0;
}

int llc_conn_ac_stop_rej_tmr_if_data_flag_eq_2(struct sock *sk,
                                               struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        if (llc->data_flag == 2)
                del_timer(&llc->rej_sent_timer.timer);
        return 0;
}

int llc_conn_ac_send_disc_cmd_p_set_x(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_U, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_CMD);
                llc_pdu_init_as_disc_cmd(nskb, 1);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
                llc_conn_ac_set_p_flag_1(sk, skb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_dm_rsp_f_set_p(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_U, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;
                u8 f_bit;

                llc_pdu_decode_pf_bit(skb, &f_bit);
                llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_dm_rsp(nskb, f_bit);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_dm_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_U, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_dm_rsp(nskb, 1);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_frmr_rsp_f_set_x(struct sock *sk, struct sk_buff *skb)
{
        u8 f_bit;
        int rc = -ENOBUFS;
        struct sk_buff *nskb;
        struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
        struct llc_sock *llc = llc_sk(sk);

        llc->rx_pdu_hdr = *((u32 *)pdu);
        if (LLC_PDU_IS_CMD(pdu))
                llc_pdu_decode_pf_bit(skb, &f_bit);
        else
                f_bit = 0;
        nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_U,
                               sizeof(struct llc_frmr_info));
        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_frmr_rsp(nskb, pdu, f_bit, llc->vS,
                                         llc->vR, INCORRECT);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_resend_frmr_rsp_f_set_0(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_U,
                                               sizeof(struct llc_frmr_info));

        if (nskb) {
                struct llc_sap *sap = llc->sap;
                struct llc_pdu_sn *pdu = (struct llc_pdu_sn *)&llc->rx_pdu_hdr;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_frmr_rsp(nskb, pdu, 0, llc->vS,
                                         llc->vR, INCORRECT);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_resend_frmr_rsp_f_set_p(struct sock *sk, struct sk_buff *skb)
{
        u8 f_bit;
        int rc = -ENOBUFS;
        struct sk_buff *nskb;
        struct llc_sock *llc = llc_sk(sk);

        llc_pdu_decode_pf_bit(skb, &f_bit);
        nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_U,
                               sizeof(struct llc_frmr_info));
        if (nskb) {
                struct llc_sap *sap = llc->sap;
                struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_frmr_rsp(nskb, pdu, f_bit, llc->vS,
                                         llc->vR, INCORRECT);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_i_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
{
        int rc;
        struct llc_sock *llc = llc_sk(sk);
        struct llc_sap *sap = llc->sap;

        llc_pdu_header_init(skb, LLC_PDU_TYPE_I, sap->laddr.lsap,
                            llc->daddr.lsap, LLC_PDU_CMD);
        llc_pdu_init_as_i_cmd(skb, 1, llc->vS, llc->vR);
        rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
        if (likely(!rc)) {
                llc_conn_send_pdu(sk, skb);
                llc_conn_ac_inc_vs_by_1(sk, skb);
        }
        return rc;
}

static int llc_conn_ac_send_i_cmd_p_set_0(struct sock *sk, struct sk_buff *skb)
{
        int rc;
        struct llc_sock *llc = llc_sk(sk);
        struct llc_sap *sap = llc->sap;

        llc_pdu_header_init(skb, LLC_PDU_TYPE_I, sap->laddr.lsap,
                            llc->daddr.lsap, LLC_PDU_CMD);
        llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR);
        rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
        if (likely(!rc)) {
                llc_conn_send_pdu(sk, skb);
                llc_conn_ac_inc_vs_by_1(sk, skb);
        }
        return rc;
}

int llc_conn_ac_send_i_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
        int rc;
        struct llc_sock *llc = llc_sk(sk);
        struct llc_sap *sap = llc->sap;

        llc_pdu_header_init(skb, LLC_PDU_TYPE_I, sap->laddr.lsap,
                            llc->daddr.lsap, LLC_PDU_CMD);
        llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR);
        rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
        if (likely(!rc)) {
                llc_conn_send_pdu(sk, skb);
                llc_conn_ac_inc_vs_by_1(sk, skb);
        }
        return 0;
}

int llc_conn_ac_resend_i_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
        struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
        u8 nr = LLC_I_GET_NR(pdu);

        llc_conn_resend_i_pdu_as_cmd(sk, nr, 0);
        return 0;
}

int llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr(struct sock *sk,
                                                struct sk_buff *skb)
{
        u8 nr;
        struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_U, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rr_rsp(nskb, 0, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (likely(!rc))
                        llc_conn_send_pdu(sk, nskb);
                else
                        kfree_skb(skb);
        }
        if (rc) {
                nr = LLC_I_GET_NR(pdu);
                rc = 0;
                llc_conn_resend_i_pdu_as_cmd(sk, nr, 0);
        }
        return rc;
}

int llc_conn_ac_resend_i_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
        struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
        u8 nr = LLC_I_GET_NR(pdu);

        llc_conn_resend_i_pdu_as_rsp(sk, nr, 1);
        return 0;
}

int llc_conn_ac_send_rej_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_CMD);
                llc_pdu_init_as_rej_cmd(nskb, 1, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_rej_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rej_rsp(nskb, 1, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_rej_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rej_rsp(nskb, 0, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_rnr_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_CMD);
                llc_pdu_init_as_rnr_cmd(nskb, 1, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_rnr_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rnr_rsp(nskb, 1, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_rnr_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rnr_rsp(nskb, 0, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_set_remote_busy(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        if (!llc->remote_busy_flag) {
                llc->remote_busy_flag = 1;
                mod_timer(&llc->busy_state_timer.timer,
                         jiffies + llc->busy_state_timer.expire);
        }
        return 0;
}

int llc_conn_ac_opt_send_rnr_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rnr_rsp(nskb, 0, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_rr_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_CMD);
                llc_pdu_init_as_rr_cmd(nskb, 1, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_rr_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;
                u8 f_bit = 1;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rr_rsp(nskb, f_bit, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_ack_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rr_rsp(nskb, 1, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_rr_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rr_rsp(nskb, 0, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_ack_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rr_rsp(nskb, 0, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

void llc_conn_set_p_flag(struct sock *sk, u8 value)
{
        int state_changed = llc_sk(sk)->p_flag && !value;

        llc_sk(sk)->p_flag = value;

        if (state_changed)
                sk->sk_state_change(sk);
}

int llc_conn_ac_send_sabme_cmd_p_set_x(struct sock *sk, struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_U, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;
                u8 *dmac = llc->daddr.mac;

                if (llc->dev->flags & IFF_LOOPBACK)
                        dmac = llc->dev->dev_addr;
                llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_CMD);
                llc_pdu_init_as_sabme_cmd(nskb, 1);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, dmac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
                llc_conn_set_p_flag(sk, 1);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_send_ua_rsp_f_set_p(struct sock *sk, struct sk_buff *skb)
{
        u8 f_bit;
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_U, 0);

        llc_pdu_decode_pf_bit(skb, &f_bit);
        if (nskb) {
                struct llc_sap *sap = llc->sap;

                nskb->dev = llc->dev;
                llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_ua_rsp(nskb, f_bit);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

int llc_conn_ac_set_s_flag_0(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->s_flag = 0;
        return 0;
}

int llc_conn_ac_set_s_flag_1(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->s_flag = 1;
        return 0;
}

int llc_conn_ac_start_p_timer(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        llc_conn_set_p_flag(sk, 1);
        mod_timer(&llc->pf_cycle_timer.timer,
                  jiffies + llc->pf_cycle_timer.expire);
        return 0;
}

/**
 *      llc_conn_ac_send_ack_if_needed - check if ack is needed
 *      @sk: current connection structure
 *      @skb: current event
 *
 *      Checks number of received PDUs which have not been acknowledged, yet,
 *      If number of them reaches to "npta"(Number of PDUs To Acknowledge) then
 *      sends an RR response as acknowledgement for them.  Returns 0 for
 *      success, 1 otherwise.
 */
int llc_conn_ac_send_ack_if_needed(struct sock *sk, struct sk_buff *skb)
{
        u8 pf_bit;
        struct llc_sock *llc = llc_sk(sk);

        llc_pdu_decode_pf_bit(skb, &pf_bit);
        llc->ack_pf |= pf_bit & 1;
        if (!llc->ack_must_be_send) {
                llc->first_pdu_Ns = llc->vR;
                llc->ack_must_be_send = 1;
                llc->ack_pf = pf_bit & 1;
        }
        if (((llc->vR - llc->first_pdu_Ns + 1 + LLC_2_SEQ_NBR_MODULO)
                        % LLC_2_SEQ_NBR_MODULO) >= llc->npta) {
                llc_conn_ac_send_rr_rsp_f_set_ackpf(sk, skb);
                llc->ack_must_be_send   = 0;
                llc->ack_pf             = 0;
                llc_conn_ac_inc_npta_value(sk, skb);
        }
        return 0;
}

/**
 *      llc_conn_ac_rst_sendack_flag - resets ack_must_be_send flag
 *      @sk: current connection structure
 *      @skb: current event
 *
 *      This action resets ack_must_be_send flag of given connection, this flag
 *      indicates if there is any PDU which has not been acknowledged yet.
 *      Returns 0 for success, 1 otherwise.
 */
int llc_conn_ac_rst_sendack_flag(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->ack_must_be_send = llc_sk(sk)->ack_pf = 0;
        return 0;
}

/**
 *      llc_conn_ac_send_i_rsp_f_set_ackpf - acknowledge received PDUs
 *      @sk: current connection structure
 *      @skb: current event
 *
 *      Sends an I response PDU with f-bit set to ack_pf flag as acknowledge to
 *      all received PDUs which have not been acknowledged, yet. ack_pf flag is
 *      set to one if one PDU with p-bit set to one is received.  Returns 0 for
 *      success, 1 otherwise.
 */
static int llc_conn_ac_send_i_rsp_f_set_ackpf(struct sock *sk,
                                              struct sk_buff *skb)
{
        int rc;
        struct llc_sock *llc = llc_sk(sk);
        struct llc_sap *sap = llc->sap;

        llc_pdu_header_init(skb, LLC_PDU_TYPE_I, sap->laddr.lsap,
                            llc->daddr.lsap, LLC_PDU_RSP);
        llc_pdu_init_as_i_cmd(skb, llc->ack_pf, llc->vS, llc->vR);
        rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
        if (likely(!rc)) {
                llc_conn_send_pdu(sk, skb);
                llc_conn_ac_inc_vs_by_1(sk, skb);
        }
        return rc;
}

/**
 *      llc_conn_ac_send_i_as_ack - sends an I-format PDU to acknowledge rx PDUs
 *      @sk: current connection structure.
 *      @skb: current event.
 *
 *      This action sends an I-format PDU as acknowledge to received PDUs which
 *      have not been acknowledged, yet, if there is any. By using of this
 *      action number of acknowledgements decreases, this technic is called
 *      piggy backing. Returns 0 for success, 1 otherwise.
 */
int llc_conn_ac_send_i_as_ack(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        if (llc->ack_must_be_send) {
                llc_conn_ac_send_i_rsp_f_set_ackpf(sk, skb);
                llc->ack_must_be_send = 0 ;
                llc->ack_pf = 0;
        } else
                llc_conn_ac_send_i_cmd_p_set_0(sk, skb);
        return 0;
}

/**
 *      llc_conn_ac_send_rr_rsp_f_set_ackpf - ack all rx PDUs not yet acked
 *      @sk: current connection structure.
 *      @skb: current event.
 *
 *      This action sends an RR response with f-bit set to ack_pf flag as
 *      acknowledge to all received PDUs which have not been acknowledged, yet,
 *      if there is any. ack_pf flag indicates if a PDU has been received with
 *      p-bit set to one. Returns 0 for success, 1 otherwise.
 */
static int llc_conn_ac_send_rr_rsp_f_set_ackpf(struct sock *sk,
                                               struct sk_buff *skb)
{
        int rc = -ENOBUFS;
        struct llc_sock *llc = llc_sk(sk);
        struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev, LLC_PDU_TYPE_S, 0);

        if (nskb) {
                struct llc_sap *sap = llc->sap;

                llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
                                    llc->daddr.lsap, LLC_PDU_RSP);
                llc_pdu_init_as_rr_rsp(nskb, llc->ack_pf, llc->vR);
                rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
                if (unlikely(rc))
                        goto free;
                llc_conn_send_pdu(sk, nskb);
        }
out:
        return rc;
free:
        kfree_skb(nskb);
        goto out;
}

/**
 *      llc_conn_ac_inc_npta_value - tries to make value of npta greater
 *      @sk: current connection structure.
 *      @skb: current event.
 *
 *      After "inc_cntr" times calling of this action, "npta" increase by one.
 *      this action tries to make vale of "npta" greater as possible; number of
 *      acknowledgements decreases by increasing of "npta". Returns 0 for
 *      success, 1 otherwise.
 */
static int llc_conn_ac_inc_npta_value(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        if (!llc->inc_cntr) {
                llc->dec_step = 0;
                llc->dec_cntr = llc->inc_cntr = 2;
                ++llc->npta;
                if (llc->npta > (u8) ~LLC_2_SEQ_NBR_MODULO)
                        llc->npta = (u8) ~LLC_2_SEQ_NBR_MODULO;
        } else
                --llc->inc_cntr;
        return 0;
}

/**
 *      llc_conn_ac_adjust_npta_by_rr - decreases "npta" by one
 *      @sk: current connection structure.
 *      @skb: current event.
 *
 *      After receiving "dec_cntr" times RR command, this action decreases
 *      "npta" by one. Returns 0 for success, 1 otherwise.
 */
int llc_conn_ac_adjust_npta_by_rr(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        if (!llc->connect_step && !llc->remote_busy_flag) {
                if (!llc->dec_step) {
                        if (!llc->dec_cntr) {
                                llc->inc_cntr = llc->dec_cntr = 2;
                                if (llc->npta > 0)
                                        llc->npta = llc->npta - 1;
                        } else
                                llc->dec_cntr -=1;
                }
        } else
                llc->connect_step = 0 ;
        return 0;
}

/**
 *      llc_conn_ac_adjust_npta_by_rnr - decreases "npta" by one
 *      @sk: current connection structure.
 *      @skb: current event.
 *
 *      After receiving "dec_cntr" times RNR command, this action decreases
 *      "npta" by one. Returns 0 for success, 1 otherwise.
 */
int llc_conn_ac_adjust_npta_by_rnr(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        if (llc->remote_busy_flag)
                if (!llc->dec_step) {
                        if (!llc->dec_cntr) {
                                llc->inc_cntr = llc->dec_cntr = 2;
                                if (llc->npta > 0)
                                        --llc->npta;
                        } else
                                --llc->dec_cntr;
                }
        return 0;
}

/**
 *      llc_conn_ac_dec_tx_win_size - decreases tx window size
 *      @sk: current connection structure.
 *      @skb: current event.
 *
 *      After receiving of a REJ command or response, transmit window size is
 *      decreased by number of PDUs which are outstanding yet. Returns 0 for
 *      success, 1 otherwise.
 */
int llc_conn_ac_dec_tx_win_size(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);
        u8 unacked_pdu = skb_queue_len(&llc->pdu_unack_q);

        if (llc->k - unacked_pdu < 1)
                llc->k = 1;
        else
                llc->k -= unacked_pdu;
        return 0;
}

/**
 *      llc_conn_ac_inc_tx_win_size - tx window size is inc by 1
 *      @sk: current connection structure.
 *      @skb: current event.
 *
 *      After receiving an RR response with f-bit set to one, transmit window
 *      size is increased by one. Returns 0 for success, 1 otherwise.
 */
int llc_conn_ac_inc_tx_win_size(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        llc->k += 1;
        if (llc->k > (u8) ~LLC_2_SEQ_NBR_MODULO)
                llc->k = (u8) ~LLC_2_SEQ_NBR_MODULO;
        return 0;
}

int llc_conn_ac_stop_all_timers(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        del_timer(&llc->pf_cycle_timer.timer);
        del_timer(&llc->ack_timer.timer);
        del_timer(&llc->rej_sent_timer.timer);
        del_timer(&llc->busy_state_timer.timer);
        llc->ack_must_be_send = 0;
        llc->ack_pf = 0;
        return 0;
}

int llc_conn_ac_stop_other_timers(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        del_timer(&llc->rej_sent_timer.timer);
        del_timer(&llc->pf_cycle_timer.timer);
        del_timer(&llc->busy_state_timer.timer);
        llc->ack_must_be_send = 0;
        llc->ack_pf = 0;
        return 0;
}

int llc_conn_ac_start_ack_timer(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        mod_timer(&llc->ack_timer.timer, jiffies + llc->ack_timer.expire);
        return 0;
}

int llc_conn_ac_start_rej_timer(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        mod_timer(&llc->rej_sent_timer.timer,
                  jiffies + llc->rej_sent_timer.expire);
        return 0;
}

int llc_conn_ac_start_ack_tmr_if_not_running(struct sock *sk,
                                             struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        if (!timer_pending(&llc->ack_timer.timer))
                mod_timer(&llc->ack_timer.timer,
                          jiffies + llc->ack_timer.expire);
        return 0;
}

int llc_conn_ac_stop_ack_timer(struct sock *sk, struct sk_buff *skb)
{
        del_timer(&llc_sk(sk)->ack_timer.timer);
        return 0;
}

int llc_conn_ac_stop_p_timer(struct sock *sk, struct sk_buff *skb)
{
        struct llc_sock *llc = llc_sk(sk);

        del_timer(&llc->pf_cycle_timer.timer);
        llc_conn_set_p_flag(sk, 0);
        return 0;
}

int llc_conn_ac_stop_rej_timer(struct sock *sk, struct sk_buff *skb)
{
        del_timer(&llc_sk(sk)->rej_sent_timer.timer);
        return 0;
}

int llc_conn_ac_upd_nr_received(struct sock *sk, struct sk_buff *skb)
{
        int acked;
        u16 unacked = 0;
        struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
        struct llc_sock *llc = llc_sk(sk);

        llc->last_nr = PDU_SUPV_GET_Nr(pdu);
        acked = llc_conn_remove_acked_pdus(sk, llc->last_nr, &unacked);
        /* On loopback we don't queue I frames in unack_pdu_q queue. */
        if (acked > 0 || (llc->dev->flags & IFF_LOOPBACK)) {
                llc->retry_count = 0;
                del_timer(&llc->ack_timer.timer);
                if (llc->failed_data_req) {
                        /* already, we did not accept data from upper layer
                         * (tx_window full or unacceptable state). Now, we
                         * can send data and must inform to upper layer.
                         */
                        llc->failed_data_req = 0;
                        llc_conn_ac_data_confirm(sk, skb);
                }
                if (unacked)
                        mod_timer(&llc->ack_timer.timer,
                                  jiffies + llc->ack_timer.expire);
        } else if (llc->failed_data_req) {
                u8 f_bit;

                llc_pdu_decode_pf_bit(skb, &f_bit);
                if (f_bit == 1) {
                        llc->failed_data_req = 0;
                        llc_conn_ac_data_confirm(sk, skb);
                }
        }
        return 0;
}

int llc_conn_ac_upd_p_flag(struct sock *sk, struct sk_buff *skb)
{
        struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

        if (LLC_PDU_IS_RSP(pdu)) {
                u8 f_bit;

                llc_pdu_decode_pf_bit(skb, &f_bit);
                if (f_bit) {
                        llc_conn_set_p_flag(sk, 0);
                        llc_conn_ac_stop_p_timer(sk, skb);
                }
        }
        return 0;
}

int llc_conn_ac_set_data_flag_2(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->data_flag = 2;
        return 0;
}

int llc_conn_ac_set_data_flag_0(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->data_flag = 0;
        return 0;
}

int llc_conn_ac_set_data_flag_1(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->data_flag = 1;
        return 0;
}

int llc_conn_ac_set_data_flag_1_if_data_flag_eq_0(struct sock *sk,
                                                  struct sk_buff *skb)
{
        if (!llc_sk(sk)->data_flag)
                llc_sk(sk)->data_flag = 1;
        return 0;
}

int llc_conn_ac_set_p_flag_0(struct sock *sk, struct sk_buff *skb)
{
        llc_conn_set_p_flag(sk, 0);
        return 0;
}

static int llc_conn_ac_set_p_flag_1(struct sock *sk, struct sk_buff *skb)
{
        llc_conn_set_p_flag(sk, 1);
        return 0;
}

int llc_conn_ac_set_remote_busy_0(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->remote_busy_flag = 0;
        return 0;
}

int llc_conn_ac_set_cause_flag_0(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->cause_flag = 0;
        return 0;
}

int llc_conn_ac_set_cause_flag_1(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->cause_flag = 1;
        return 0;
}

int llc_conn_ac_set_retry_cnt_0(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->retry_count = 0;
        return 0;
}

int llc_conn_ac_inc_retry_cnt_by_1(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->retry_count++;
        return 0;
}

int llc_conn_ac_set_vr_0(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->vR = 0;
        return 0;
}

int llc_conn_ac_inc_vr_by_1(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->vR = PDU_GET_NEXT_Vr(llc_sk(sk)->vR);
        return 0;
}

int llc_conn_ac_set_vs_0(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->vS = 0;
        return 0;
}

int llc_conn_ac_set_vs_nr(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->vS = llc_sk(sk)->last_nr;
        return 0;
}

static int llc_conn_ac_inc_vs_by_1(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->vS = (llc_sk(sk)->vS + 1) % LLC_2_SEQ_NBR_MODULO;
        return 0;
}

static void llc_conn_tmr_common_cb(unsigned long timeout_data, u8 type)
{
        struct sock *sk = (struct sock *)timeout_data;
        struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC);

        bh_lock_sock(sk);
        if (skb) {
                struct llc_conn_state_ev *ev = llc_conn_ev(skb);

                skb_set_owner_r(skb, sk);
                ev->type = type;
                llc_process_tmr_ev(sk, skb);
        }
        bh_unlock_sock(sk);
}

void llc_conn_pf_cycle_tmr_cb(unsigned long timeout_data)
{
        llc_conn_tmr_common_cb(timeout_data, LLC_CONN_EV_TYPE_P_TMR);
}

void llc_conn_busy_tmr_cb(unsigned long timeout_data)
{
        llc_conn_tmr_common_cb(timeout_data, LLC_CONN_EV_TYPE_BUSY_TMR);
}

void llc_conn_ack_tmr_cb(unsigned long timeout_data)
{
        llc_conn_tmr_common_cb(timeout_data, LLC_CONN_EV_TYPE_ACK_TMR);
}

void llc_conn_rej_tmr_cb(unsigned long timeout_data)
{
        llc_conn_tmr_common_cb(timeout_data, LLC_CONN_EV_TYPE_REJ_TMR);
}

int llc_conn_ac_rst_vs(struct sock *sk, struct sk_buff *skb)
{
        llc_sk(sk)->X = llc_sk(sk)->vS;
        llc_conn_ac_set_vs_nr(sk, skb);
        return 0;
}

int llc_conn_ac_upd_vs(struct sock *sk, struct sk_buff *skb)
{
        struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
        u8 nr = PDU_SUPV_GET_Nr(pdu);

        if (llc_circular_between(llc_sk(sk)->vS, nr, llc_sk(sk)->X))
                llc_conn_ac_set_vs_nr(sk, skb);
        return 0;
}

/*
 * Non-standard actions; these not contained in IEEE specification; for
 * our own usage
 */
/**
 *      llc_conn_disc - removes connection from SAP list and frees it
 *      @sk: closed connection
 *      @skb: occurred event
 */
int llc_conn_disc(struct sock *sk, struct sk_buff *skb)
{
        /* FIXME: this thing seems to want to die */
        return 0;
}

/**
 *      llc_conn_reset - resets connection
 *      @sk : reseting connection.
 *      @skb: occurred event.
 *
 *      Stop all timers, empty all queues and reset all flags.
 */
int llc_conn_reset(struct sock *sk, struct sk_buff *skb)
{
        llc_sk_reset(sk);
        return 0;
}

/**
 *      llc_circular_between - designates that b is between a and c or not
 *      @a: lower bound
 *      @b: element to see if is between a and b
 *      @c: upper bound
 *
 *      This function designates that b is between a and c or not (for example,
 *      0 is between 127 and 1). Returns 1 if b is between a and c, 0
 *      otherwise.
 */
u8 llc_circular_between(u8 a, u8 b, u8 c)
{
        b = b - a;
        c = c - a;
        return b <= c;
}

/**
 *      llc_process_tmr_ev - timer backend
 *      @sk: active connection
 *      @skb: occurred event
 *
 *      This function is called from timer callback functions. When connection
 *      is busy (during sending a data frame) timer expiration event must be
 *      queued. Otherwise this event can be sent to connection state machine.
 *      Queued events will process by llc_backlog_rcv function after sending
 *      data frame.
 */
static void llc_process_tmr_ev(struct sock *sk, struct sk_buff *skb)
{
        if (llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC) {
                printk(KERN_WARNING "%s: timer called on closed connection\n",
                       __func__);
                kfree_skb(skb);
        } else {
                if (!sock_owned_by_user(sk))
                        llc_conn_state_process(sk, skb);
                else {
                        llc_set_backlog_type(skb, LLC_EVENT);
                        __sk_add_backlog(sk, skb);
                }
        }
}