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 FILE_LICENCE ( GPL2_OR_LATER );
  20
  21 #include <stdint.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <byteswap.h>
  25 #include <errno.h>
  26 #include <assert.h>
  27 #include <gpxe/if_arp.h>
  28 #include <gpxe/if_ether.h>
  29 #include <gpxe/in.h>
  30 #include <gpxe/netdevice.h>
  31 #include <gpxe/iobuf.h>
  32 #include <gpxe/ethernet.h>
  33
  34 /** @file
  35  *
  36  * Ethernet protocol
  37  *
  38  */
  39
  40 /** Ethernet broadcast MAC address */
  41 static uint8_t eth_broadcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
  42
  43 /**
  44  * Add Ethernet link-layer header
  45  *
  46  * @v netdev            Network device
  47  * @v iobuf             I/O buffer
  48  * @v ll_dest           Link-layer destination address
  49  * @v ll_source         Source link-layer address
  50  * @v net_proto         Network-layer protocol, in network-byte order
  51  * @ret rc              Return status code
  52  */
  53 static int eth_push ( struct net_device *netdev __unused,
  54                       struct io_buffer *iobuf, const void *ll_dest,
  55                       const void *ll_source, uint16_t net_proto ) {
  56         struct ethhdr *ethhdr = iob_push ( iobuf, sizeof ( *ethhdr ) );
  57
  58         /* Build Ethernet header */
  59         memcpy ( ethhdr->h_dest, ll_dest, ETH_ALEN );
  60         memcpy ( ethhdr->h_source, ll_source, ETH_ALEN );
  61         ethhdr->h_protocol = net_proto;
  62
  63         return 0;
  64 }
  65
  66 /**
  67  * Remove Ethernet link-layer header
  68  *
  69  * @v netdev            Network device
  70  * @v iobuf             I/O buffer
  71  * @ret ll_dest         Link-layer destination address
  72  * @ret ll_source       Source link-layer address
  73  * @ret net_proto       Network-layer protocol, in network-byte order
  74  * @ret rc              Return status code
  75  */
  76 static int eth_pull ( struct net_device *netdev __unused,
  77                       struct io_buffer *iobuf, const void **ll_dest,
  78                       const void **ll_source, uint16_t *net_proto ) {
  79         struct ethhdr *ethhdr = iobuf->data;
  80
  81         /* Sanity check */
  82         if ( iob_len ( iobuf ) < sizeof ( *ethhdr ) ) {
  83                 DBG ( "Ethernet packet too short (%zd bytes)\n",
  84                       iob_len ( iobuf ) );
  85                 return -EINVAL;
  86         }
  87
  88         /* Strip off Ethernet header */
  89         iob_pull ( iobuf, sizeof ( *ethhdr ) );
  90
  91         /* Fill in required fields */
  92         *ll_dest = ethhdr->h_dest;
  93         *ll_source = ethhdr->h_source;
  94         *net_proto = ethhdr->h_protocol;
  95
  96         return 0;
  97 }
  98
  99 /**
 100  * Initialise Ethernet address
 101  *
 102  * @v hw_addr           Hardware address
 103  * @v ll_addr           Link-layer address
 104  */
 105 void eth_init_addr ( const void *hw_addr, void *ll_addr ) {
 106         memcpy ( ll_addr, hw_addr, ETH_ALEN );
 107 }
 108
 109 /**
 110  * Transcribe Ethernet address
 111  *
 112  * @v ll_addr           Link-layer address
 113  * @ret string          Link-layer address in human-readable format
 114  */
 115 const char * eth_ntoa ( const void *ll_addr ) {
 116         static char buf[18]; /* "00:00:00:00:00:00" */
 117         const uint8_t *eth_addr = ll_addr;
 118
 119         sprintf ( buf, "%02x:%02x:%02x:%02x:%02x:%02x",
 120                   eth_addr[0], eth_addr[1], eth_addr[2],
 121                   eth_addr[3], eth_addr[4], eth_addr[5] );
 122         return buf;
 123 }
 124
 125 /**
 126  * Hash multicast address
 127  *
 128  * @v af                Address family
 129  * @v net_addr          Network-layer address
 130  * @v ll_addr           Link-layer address to fill in
 131  * @ret rc              Return status code
 132  */
 133 int eth_mc_hash ( unsigned int af, const void *net_addr, void *ll_addr ) {
 134         const uint8_t *net_addr_bytes = net_addr;
 135         uint8_t *ll_addr_bytes = ll_addr;
 136
 137         switch ( af ) {
 138         case AF_INET:
 139                 ll_addr_bytes[0] = 0x01;
 140                 ll_addr_bytes[1] = 0x00;
 141                 ll_addr_bytes[2] = 0x5e;
 142                 ll_addr_bytes[3] = net_addr_bytes[1] & 0x7f;
 143                 ll_addr_bytes[4] = net_addr_bytes[2];
 144                 ll_addr_bytes[5] = net_addr_bytes[3];
 145                 return 0;
 146         default:
 147                 return -ENOTSUP;
 148         }
 149 }
 150
 151 /** Ethernet protocol */
 152 struct ll_protocol ethernet_protocol __ll_protocol = {
 153         .name           = "Ethernet",
 154         .ll_proto       = htons ( ARPHRD_ETHER ),
 155         .hw_addr_len    = ETH_ALEN,
 156         .ll_addr_len    = ETH_ALEN,
 157         .ll_header_len  = ETH_HLEN,
 158         .push           = eth_push,
 159         .pull           = eth_pull,
 160         .init_addr      = eth_init_addr,
 161         .ntoa           = eth_ntoa,
 162         .mc_hash        = eth_mc_hash,
 163 };
 164
 165 /**
 166  * Allocate Ethernet device
 167  *
 168  * @v priv_size         Size of driver private data
 169  * @ret netdev          Network device, or NULL
 170  */
 171 struct net_device * alloc_etherdev ( size_t priv_size ) {
 172         struct net_device *netdev;
 173
 174         netdev = alloc_netdev ( priv_size );
 175         if ( netdev ) {
 176                 netdev->ll_protocol = &ethernet_protocol;
 177                 netdev->ll_broadcast = eth_broadcast;
 178                 netdev->max_pkt_len = ETH_FRAME_LEN;
 179         }
 180         return netdev;
 181 }