LXR linux/net/llc/llc

   1/*
   2 * llc_output.c - LLC minimal output path
   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 version 2 as published by the Free Software
   9 * Foundation.
  10 * This program is distributed without any warranty or implied warranty
  11 * of merchantability or fitness for a particular purpose.
  12 *
  13 * See the GNU General Public License version 2 for more details.
  14 */
  15
  16#include <linux/if_arp.h>
  17#include <linux/netdevice.h>
  18#include <linux/skbuff.h>
  19#include <linux/export.h>
  20#include <net/llc.h>
  21#include <net/llc_pdu.h>
  22
  23/**
  24 *      llc_mac_hdr_init - fills MAC header fields
  25 *      @skb: Address of the frame to initialize its MAC header
  26 *      @sa: The MAC source address
  27 *      @da: The MAC destination address
  28 *
  29 *      Fills MAC header fields, depending on MAC type. Returns 0, If MAC type
  30 *      is a valid type and initialization completes correctly 1, otherwise.
  31 */
  32int llc_mac_hdr_init(struct sk_buff *skb,
  33                     const unsigned char *sa, const unsigned char *da)
  34{
  35        int rc = -EINVAL;
  36
  37        switch (skb->dev->type) {
  38        case ARPHRD_ETHER:
  39        case ARPHRD_LOOPBACK:
  40                rc = dev_hard_header(skb, skb->dev, ETH_P_802_2, da, sa,
  41                                     skb->len);
  42                if (rc > 0)
  43                        rc = 0;
  44                break;
  45        default:
  46                break;
  47        }
  48        return rc;
  49}
  50
  51/**
  52 *      llc_build_and_send_ui_pkt - unitdata request interface for upper layers
  53 *      @sap: sap to use
  54 *      @skb: packet to send
  55 *      @dmac: destination mac address
  56 *      @dsap: destination sap
  57 *
  58 *      Upper layers calls this function when upper layer wants to send data
  59 *      using connection-less mode communication (UI pdu).
  60 *
  61 *      Accept data frame from network layer to be sent using connection-
  62 *      less mode communication; timeout/retries handled by network layer;
  63 *      package primitive as an event and send to SAP event handler
  64 */
  65int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb,
  66                              unsigned char *dmac, unsigned char dsap)
  67{
  68        int rc;
  69        llc_pdu_header_init(skb, LLC_PDU_TYPE_U, sap->laddr.lsap,
  70                            dsap, LLC_PDU_CMD);
  71        llc_pdu_init_as_ui_cmd(skb);
  72        rc = llc_mac_hdr_init(skb, skb->dev->dev_addr, dmac);
  73        if (likely(!rc))
  74                rc = dev_queue_xmit(skb);
  75        else
  76                kfree_skb(skb);
  77        return rc;
  78}
  79
  80EXPORT_SYMBOL(llc_mac_hdr_init);
  81EXPORT_SYMBOL(llc_build_and_send_ui_pkt);
  82