net/llc/llc_output.c

   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  */
  32 int 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                 WARN(1, "device type not supported: %d\n", skb->dev->type);
  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  */
  65 int 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         return rc;
  76 }
  77
  78 EXPORT_SYMBOL(llc_mac_hdr_init);
  79 EXPORT_SYMBOL(llc_build_and_send_ui_pkt);