net/llc/llc_if.c

   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/config.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/netdevice.h>
  18 #include <asm/errno.h>
  19 #include <net/llc_if.h>
  20 #include <net/llc_sap.h>
  21 #include <net/llc_s_ev.h>
  22 #include <net/llc_conn.h>
  23 #include <net/sock.h>
  24 #include <net/llc_c_ev.h>
  25 #include <net/llc_c_ac.h>
  26 #include <net/llc_c_st.h>
  27 #include <net/tcp_states.h>
  28
  29 u8 llc_mac_null_var[IFHWADDRLEN];
  30
  31 /**
  32  *      llc_build_and_send_pkt - Connection data sending for upper layers.
  33  *      @sk: connection
  34  *      @skb: packet to send
  35  *
  36  *      This function is called when upper layer wants to send data using
  37  *      connection oriented communication mode. During sending data, connection
  38  *      will be locked and received frames and expired timers will be queued.
  39  *      Returns 0 for success, -ECONNABORTED when the connection already
  40  *      closed and -EBUSY when sending data is not permitted in this state or
  41  *      LLC has send an I pdu with p bit set to 1 and is waiting for it's
  42  *      response.
  43  */
  44 int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb)
  45 {
  46         struct llc_conn_state_ev *ev;
  47         int rc = -ECONNABORTED;
  48         struct llc_sock *llc = llc_sk(sk);
  49
  50         if (unlikely(llc->state == LLC_CONN_STATE_ADM))
  51                 goto out;
  52         rc = -EBUSY;
  53         if (unlikely(llc_data_accept_state(llc->state) || /* data_conn_refuse */
  54                      llc->p_flag)) {
  55                 llc->failed_data_req = 1;
  56                 goto out;
  57         }
  58         ev = llc_conn_ev(skb);
  59         ev->type      = LLC_CONN_EV_TYPE_PRIM;
  60         ev->prim      = LLC_DATA_PRIM;
  61         ev->prim_type = LLC_PRIM_TYPE_REQ;
  62         skb->dev      = llc->dev;
  63         rc = llc_conn_state_process(sk, skb);
  64 out:
  65         return rc;
  66 }
  67
  68 /**
  69  *      llc_establish_connection - Called by upper layer to establish a conn
  70  *      @sk: connection
  71  *      @lmac: local mac address
  72  *      @dmac: destination mac address
  73  *      @dsap: destination sap
  74  *
  75  *      Upper layer calls this to establish an LLC connection with a remote
  76  *      machine. This function packages a proper event and sends it connection
  77  *      component state machine. Success or failure of connection
  78  *      establishment will inform to upper layer via calling it's confirm
  79  *      function and passing proper information.
  80  */
  81 int llc_establish_connection(struct sock *sk, u8 *lmac, u8 *dmac, u8 dsap)
  82 {
  83         int rc = -EISCONN;
  84         struct llc_addr laddr, daddr;
  85         struct sk_buff *skb;
  86         struct llc_sock *llc = llc_sk(sk);
  87         struct sock *existing;
  88
  89         laddr.lsap = llc->sap->laddr.lsap;
  90         daddr.lsap = dsap;
  91         memcpy(daddr.mac, dmac, sizeof(daddr.mac));
  92         memcpy(laddr.mac, lmac, sizeof(laddr.mac));
  93         existing = llc_lookup_established(llc->sap, &daddr, &laddr);
  94         if (existing) {
  95                 if (existing->sk_state == TCP_ESTABLISHED) {
  96                         sk = existing;
  97                         goto out_put;
  98                 } else
  99                         sock_put(existing);
 100         }
 101         sock_hold(sk);
 102         rc = -ENOMEM;
 103         skb = alloc_skb(0, GFP_ATOMIC);
 104         if (skb) {
 105                 struct llc_conn_state_ev *ev = llc_conn_ev(skb);
 106
 107                 ev->type      = LLC_CONN_EV_TYPE_PRIM;
 108                 ev->prim      = LLC_CONN_PRIM;
 109                 ev->prim_type = LLC_PRIM_TYPE_REQ;
 110                 skb_set_owner_w(skb, sk);
 111                 rc = llc_conn_state_process(sk, skb);
 112         }
 113 out_put:
 114         sock_put(sk);
 115         return rc;
 116 }
 117
 118 /**
 119  *      llc_send_disc - Called by upper layer to close a connection
 120  *      @sk: connection to be closed
 121  *
 122  *      Upper layer calls this when it wants to close an established LLC
 123  *      connection with a remote machine. This function packages a proper event
 124  *      and sends it to connection component state machine. Returns 0 for
 125  *      success, 1 otherwise.
 126  */
 127 int llc_send_disc(struct sock *sk)
 128 {
 129         u16 rc = 1;
 130         struct llc_conn_state_ev *ev;
 131         struct sk_buff *skb;
 132
 133         sock_hold(sk);
 134         if (sk->sk_type != SOCK_STREAM || sk->sk_state != TCP_ESTABLISHED ||
 135             llc_sk(sk)->state == LLC_CONN_STATE_ADM ||
 136             llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC)
 137                 goto out;
 138         /*
 139          * Postpone unassigning the connection from its SAP and returning the
 140          * connection until all ACTIONs have been completely executed
 141          */
 142         skb = alloc_skb(0, GFP_ATOMIC);
 143         if (!skb)
 144                 goto out;
 145         skb_set_owner_w(skb, sk);
 146         sk->sk_state  = TCP_CLOSING;
 147         ev            = llc_conn_ev(skb);
 148         ev->type      = LLC_CONN_EV_TYPE_PRIM;
 149         ev->prim      = LLC_DISC_PRIM;
 150         ev->prim_type = LLC_PRIM_TYPE_REQ;
 151         rc = llc_conn_state_process(sk, skb);
 152 out:
 153         sock_put(sk);
 154         return rc;
 155 }
 156