LXR linux/net/llc/llc

   1/*
   2 * llc_if.c - Defines LLC interface to upper layer
   3 *
   4 * Copyright (c) 1997 by Procom Technology, Inc.
   5 *               2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   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#include <linux/module.h>
  15#include <linux/kernel.h>
  16#include <linux/netdevice.h>
  17#include <asm/errno.h>
  18#include <net/llc_if.h>
  19#include <net/llc_sap.h>
  20#include <net/llc_s_ev.h>
  21#include <net/llc_conn.h>
  22#include <net/sock.h>
  23#include <net/llc_c_ev.h>
  24#include <net/llc_c_ac.h>
  25#include <net/llc_c_st.h>
  26#include <net/tcp_states.h>
  27
  28/**
  29 *      llc_build_and_send_pkt - Connection data sending for upper layers.
  30 *      @sk: connection
  31 *      @skb: packet to send
  32 *
  33 *      This function is called when upper layer wants to send data using
  34 *      connection oriented communication mode. During sending data, connection
  35 *      will be locked and received frames and expired timers will be queued.
  36 *      Returns 0 for success, -ECONNABORTED when the connection already
  37 *      closed and -EBUSY when sending data is not permitted in this state or
  38 *      LLC has send an I pdu with p bit set to 1 and is waiting for it's
  39 *      response.
  40 */
  41int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb)
  42{
  43        struct llc_conn_state_ev *ev;
  44        int rc = -ECONNABORTED;
  45        struct llc_sock *llc = llc_sk(sk);
  46
  47        if (unlikely(llc->state == LLC_CONN_STATE_ADM))
  48                goto out;
  49        rc = -EBUSY;
  50        if (unlikely(llc_data_accept_state(llc->state) || /* data_conn_refuse */
  51                     llc->p_flag)) {
  52                llc->failed_data_req = 1;
  53                goto out;
  54        }
  55        ev = llc_conn_ev(skb);
  56        ev->type      = LLC_CONN_EV_TYPE_PRIM;
  57        ev->prim      = LLC_DATA_PRIM;
  58        ev->prim_type = LLC_PRIM_TYPE_REQ;
  59        skb->dev      = llc->dev;
  60        rc = llc_conn_state_process(sk, skb);
  61out:
  62        return rc;
  63}
  64
  65/**
  66 *      llc_establish_connection - Called by upper layer to establish a conn
  67 *      @sk: connection
  68 *      @lmac: local mac address
  69 *      @dmac: destination mac address
  70 *      @dsap: destination sap
  71 *
  72 *      Upper layer calls this to establish an LLC connection with a remote
  73 *      machine. This function packages a proper event and sends it connection
  74 *      component state machine. Success or failure of connection
  75 *      establishment will inform to upper layer via calling it's confirm
  76 *      function and passing proper information.
  77 */
  78int llc_establish_connection(struct sock *sk, u8 *lmac, u8 *dmac, u8 dsap)
  79{
  80        int rc = -EISCONN;
  81        struct llc_addr laddr, daddr;
  82        struct sk_buff *skb;
  83        struct llc_sock *llc = llc_sk(sk);
  84        struct sock *existing;
  85
  86        laddr.lsap = llc->sap->laddr.lsap;
  87        daddr.lsap = dsap;
  88        memcpy(daddr.mac, dmac, sizeof(daddr.mac));
  89        memcpy(laddr.mac, lmac, sizeof(laddr.mac));
  90        existing = llc_lookup_established(llc->sap, &daddr, &laddr);
  91        if (existing) {
  92                if (existing->sk_state == TCP_ESTABLISHED) {
  93                        sk = existing;
  94                        goto out_put;
  95                } else
  96                        sock_put(existing);
  97        }
  98        sock_hold(sk);
  99        rc = -ENOMEM;
 100        skb = alloc_skb(0, GFP_ATOMIC);
 101        if (skb) {
 102                struct llc_conn_state_ev *ev = llc_conn_ev(skb);
 103
 104                ev->type      = LLC_CONN_EV_TYPE_PRIM;
 105                ev->prim      = LLC_CONN_PRIM;
 106                ev->prim_type = LLC_PRIM_TYPE_REQ;
 107                skb_set_owner_w(skb, sk);
 108                rc = llc_conn_state_process(sk, skb);
 109        }
 110out_put:
 111        sock_put(sk);
 112        return rc;
 113}
 114
 115/**
 116 *      llc_send_disc - Called by upper layer to close a connection
 117 *      @sk: connection to be closed
 118 *
 119 *      Upper layer calls this when it wants to close an established LLC
 120 *      connection with a remote machine. This function packages a proper event
 121 *      and sends it to connection component state machine. Returns 0 for
 122 *      success, 1 otherwise.
 123 */
 124int llc_send_disc(struct sock *sk)
 125{
 126        u16 rc = 1;
 127        struct llc_conn_state_ev *ev;
 128        struct sk_buff *skb;
 129
 130        sock_hold(sk);
 131        if (sk->sk_type != SOCK_STREAM || sk->sk_state != TCP_ESTABLISHED ||
 132            llc_sk(sk)->state == LLC_CONN_STATE_ADM ||
 133            llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC)
 134                goto out;
 135        /*
 136         * Postpone unassigning the connection from its SAP and returning the
 137         * connection until all ACTIONs have been completely executed
 138         */
 139        skb = alloc_skb(0, GFP_ATOMIC);
 140        if (!skb)
 141                goto out;
 142        skb_set_owner_w(skb, sk);
 143        sk->sk_state  = TCP_CLOSING;
 144        ev            = llc_conn_ev(skb);
 145        ev->type      = LLC_CONN_EV_TYPE_PRIM;
 146        ev->prim      = LLC_DISC_PRIM;
 147        ev->prim_type = LLC_PRIM_TYPE_REQ;
 148        rc = llc_conn_state_process(sk, skb);
 149out:
 150        sock_put(sk);
 151        return rc;
 152}
 153
 154