llc_if.c

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/*
 * llc_if.c - Defines LLC interface to upper layer
 *
 * 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/gfp.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <asm/errno.h>
#include <net/llc_if.h>
#include <net/llc_sap.h>
#include <net/llc_s_ev.h>
#include <net/llc_conn.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/tcp_states.h>

int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb)
{
    struct llc_conn_state_ev *ev;
    int rc = -ECONNABORTED;
    struct llc_sock *llc = llc_sk(sk);

    if (unlikely(llc->state == LLC_CONN_STATE_ADM))
        goto out;
    rc = -EBUSY;
    if (unlikely(llc_data_accept_state(llc->state) || /* data_conn_refuse */
             llc->p_flag)) {
        llc->failed_data_req = 1;
        goto out;
    }
    ev = llc_conn_ev(skb);
    ev->type      = LLC_CONN_EV_TYPE_PRIM;
    ev->prim      = LLC_DATA_PRIM;
    ev->prim_type = LLC_PRIM_TYPE_REQ;
    skb->dev      = llc->dev;
    rc = llc_conn_state_process(sk, skb);
out:
    return rc;
}

int llc_establish_connection(struct sock *sk, u8 *lmac, u8 *dmac, u8 dsap)
{
    int rc = -EISCONN;
    struct llc_addr laddr, daddr;
    struct sk_buff *skb;
    struct llc_sock *llc = llc_sk(sk);
    struct sock *existing;

    laddr.lsap = llc->sap->laddr.lsap;
    daddr.lsap = dsap;
    memcpy(daddr.mac, dmac, sizeof(daddr.mac));
    memcpy(laddr.mac, lmac, sizeof(laddr.mac));
    existing = llc_lookup_established(llc->sap, &daddr, &laddr);
    if (existing) {
        if (existing->sk_state == TCP_ESTABLISHED) {
            sk = existing;
            goto out_put;
        } else
            sock_put(existing);
    }
    sock_hold(sk);
    rc = -ENOMEM;
    skb = alloc_skb(0, GFP_ATOMIC);
    if (skb) {
        struct llc_conn_state_ev *ev = llc_conn_ev(skb);

        ev->type      = LLC_CONN_EV_TYPE_PRIM;
        ev->prim      = LLC_CONN_PRIM;
        ev->prim_type = LLC_PRIM_TYPE_REQ;
        skb_set_owner_w(skb, sk);
        rc = llc_conn_state_process(sk, skb);
    }
out_put:
    sock_put(sk);
    return rc;
}

int llc_send_disc(struct sock *sk)
{
    u16 rc = 1;
    struct llc_conn_state_ev *ev;
    struct sk_buff *skb;

    sock_hold(sk);
    if (sk->sk_type != SOCK_STREAM || sk->sk_state != TCP_ESTABLISHED ||
        llc_sk(sk)->state == LLC_CONN_STATE_ADM ||
        llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC)
        goto out;
    /*
     * Postpone unassigning the connection from its SAP and returning the
     * connection until all ACTIONs have been completely executed
     */
    skb = alloc_skb(0, GFP_ATOMIC);
    if (!skb)
        goto out;
    skb_set_owner_w(skb, sk);
    sk->sk_state  = TCP_CLOSING;
    ev        = llc_conn_ev(skb);
    ev->type      = LLC_CONN_EV_TYPE_PRIM;
    ev->prim      = LLC_DISC_PRIM;
    ev->prim_type = LLC_PRIM_TYPE_REQ;
    rc = llc_conn_state_process(sk, skb);
out:
    sock_put(sk);
    return rc;
}