gpxe/src/net/ethernet.c

   1 /*
   2  * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 #include <stdint.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <byteswap.h>
  23 #include <errno.h>
  24 #include <assert.h>
  25 #include <gpxe/if_arp.h>
  26 #include <gpxe/if_ether.h>
  27 #include <gpxe/netdevice.h>
  28 #include <gpxe/iobuf.h>
  29 #include <gpxe/ethernet.h>
  30
  31 /** @file
  32  *
  33  * Ethernet protocol
  34  *
  35  */
  36
  37 /** Ethernet broadcast MAC address */
  38 static uint8_t eth_broadcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
  39
  40 /**
  41  * Transmit Ethernet packet
  42  *
  43  * @v iobuf             I/O buffer
  44  * @v netdev            Network device
  45  * @v net_protocol      Network-layer protocol
  46  * @v ll_dest           Link-layer destination address
  47  *
  48  * Prepends the Ethernet link-layer header and transmits the packet.
  49  */
  50 static int eth_tx ( struct io_buffer *iobuf, struct net_device *netdev,
  51                     struct net_protocol *net_protocol, const void *ll_dest ) {
  52         struct ethhdr *ethhdr = iob_push ( iobuf, sizeof ( *ethhdr ) );
  53
  54         /* Build Ethernet header */
  55         memcpy ( ethhdr->h_dest, ll_dest, ETH_ALEN );
  56         memcpy ( ethhdr->h_source, netdev->ll_addr, ETH_ALEN );
  57         ethhdr->h_protocol = net_protocol->net_proto;
  58
  59         /* Hand off to network device */
  60         return netdev_tx ( netdev, iobuf );
  61 }
  62
  63 /**
  64  * Process received Ethernet packet
  65  *
  66  * @v iobuf     I/O buffer
  67  * @v netdev    Network device
  68  *
  69  * Strips off the Ethernet link-layer header and passes up to the
  70  * network-layer protocol.
  71  */
  72 static int eth_rx ( struct io_buffer *iobuf, struct net_device *netdev ) {
  73         struct ethhdr *ethhdr = iobuf->data;
  74
  75         /* Sanity check */
  76         if ( iob_len ( iobuf ) < sizeof ( *ethhdr ) ) {
  77                 DBG ( "Ethernet packet too short (%zd bytes)\n",
  78                       iob_len ( iobuf ) );
  79                 free_iob ( iobuf );
  80                 return -EINVAL;
  81         }
  82
  83         /* Strip off Ethernet header */
  84         iob_pull ( iobuf, sizeof ( *ethhdr ) );
  85
  86         /* Hand off to network-layer protocol */
  87         return net_rx ( iobuf, netdev, ethhdr->h_protocol, ethhdr->h_source );
  88 }
  89
  90 /**
  91  * Transcribe Ethernet address
  92  *
  93  * @v ll_addr   Link-layer address
  94  * @ret string  Link-layer address in human-readable format
  95  */
  96 const char * eth_ntoa ( const void *ll_addr ) {
  97         static char buf[18]; /* "00:00:00:00:00:00" */
  98         const uint8_t *eth_addr = ll_addr;
  99
 100         sprintf ( buf, "%02x:%02x:%02x:%02x:%02x:%02x",
 101                   eth_addr[0], eth_addr[1], eth_addr[2],
 102                   eth_addr[3], eth_addr[4], eth_addr[5] );
 103         return buf;
 104 }
 105
 106 /** Ethernet protocol */
 107 struct ll_protocol ethernet_protocol __ll_protocol = {
 108         .name           = "Ethernet",
 109         .ll_proto       = htons ( ARPHRD_ETHER ),
 110         .ll_addr_len    = ETH_ALEN,
 111         .ll_header_len  = ETH_HLEN,
 112         .ll_broadcast   = eth_broadcast,
 113         .tx             = eth_tx,
 114         .rx             = eth_rx,
 115         .ntoa           = eth_ntoa,
 116 };