root/net/inet/eth.c

/* */

DEFINITIONS

1. eth_print
2. eth_dump
3. eth_header
4. eth_rebuild_header
5. eth_add_arp
6. eth_type_trans

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Ethernet-type device handling.
   7  *
   8  * Version:     @(#)eth.c       1.0.7   05/25/93
   9  *
  10  * Authors:     Ross Biro, <bir7@leland.Stanford.Edu>
  11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
  13  *
  14  *              This program is free software; you can redistribute it and/or
  15  *              modify it under the terms of the GNU General Public License
  16  *              as published by the Free Software Foundation; either version
  17  *              2 of the License, or (at your option) any later version.
  18  */
  19 #include <asm/segment.h>
  20 #include <asm/system.h>
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/string.h>
  25 #include <linux/mm.h>
  26 #include <linux/socket.h>
  27 #include <linux/in.h>
  28 #include "inet.h"
  29 #include "dev.h"
  30 #include "eth.h"
  31 #include "timer.h"
  32 #include "ip.h"
  33 #include "route.h"
  34 #include "protocol.h"
  35 #include "tcp.h"
  36 #include "skbuff.h"
  37 #include "sock.h"
  38 #include <linux/errno.h>
  39 #include "arp.h"
  40 
  41 
  42 /* Display an Ethernet address in readable format. */
  43 char *eth_print(unsigned char *ptr)
     /*  */
  44 {
  45   static char buff[64];
  46 
  47   if (ptr == NULL) return("[NONE]");
  48   sprintf(buff, "%02X:%02X:%02X:%02X:%02X:%02X",
  49         (ptr[0] & 255), (ptr[1] & 255), (ptr[2] & 255),
  50         (ptr[3] & 255), (ptr[4] & 255), (ptr[5] & 255)
  51   );
  52   return(buff);
  53 }
  54 
  55 
  56 /* Display the contents of the Ethernet MAC header. */
  57 void
  58 eth_dump(struct ethhdr *eth)
     /*  */
  59 {
  60   if (inet_debug != DBG_ETH) return;
  61 
  62   printk("eth: SRC = %s ", eth_print(eth->h_source));
  63   printk("DST = %s ", eth_print(eth->h_dest));
  64   printk("TYPE = %04X\n", ntohs(eth->h_proto));
  65 }
  66 
  67 
  68 /* Create the Ethernet MAC header. */
  69 int
  70 eth_header(unsigned char *buff, struct device *dev, unsigned short type,
     /*  */
  71            unsigned long daddr, unsigned long saddr, unsigned len)
  72 {
  73   struct ethhdr *eth;
  74 
  75   DPRINTF((DBG_DEV, "ETH: header(%s, ", in_ntoa(saddr)));
  76   DPRINTF((DBG_DEV, "%s, 0x%X)\n", in_ntoa(daddr), type));
  77 
  78   /* Fill in the basic Ethernet MAC header. */
  79   eth = (struct ethhdr *) buff;
  80   eth->h_proto = ntohs(type);
  81   memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
  82 
  83   /* We don't ARP for the LOOPBACK device... */
  84   if (dev->flags & IFF_LOOPBACK) {
  85         DPRINTF((DBG_DEV, "ETH: No header for loopback\n"));
  86         memset(eth->h_dest, 0, dev->addr_len);
  87         return(dev->hard_header_len);
  88   }
  89 
  90   /* Check if we can use the MAC BROADCAST address. */
  91   if (chk_addr(daddr) == IS_BROADCAST) {
  92         DPRINTF((DBG_DEV, "ETH: Using MAC Broadcast\n"));
  93         memcpy(eth->h_dest, dev->broadcast, dev->addr_len);
  94         return(dev->hard_header_len);
  95   }
  96 
  97   /* No. Ask ARP to resolve the Ethernet address. */
  98   if (arp_find(eth->h_dest, daddr, dev, saddr)) {
  99         return(-dev->hard_header_len);
 100   } else return(dev->hard_header_len);
 101 }
 102 
 103 
 104 /* Rebuild the Ethernet MAC header. */
 105 int
 106 eth_rebuild_header(void *buff, struct device *dev)
     /*  */
 107 {
 108   struct ethhdr *eth;
 109   unsigned long src, dst;
 110 
 111   DPRINTF((DBG_DEV, "ETH: Using MAC Broadcast\n"));
 112   eth = buff;
 113   src = *(unsigned long *) eth->h_source;
 114   dst = *(unsigned long *) eth->h_dest;
 115   DPRINTF((DBG_DEV, "ETH: RebuildHeader: SRC=%s ", in_ntoa(src)));
 116   DPRINTF((DBG_DEV, "DST=%s\n", in_ntoa(dst)));
 117   if (arp_find(eth->h_dest, dst, dev, src)) return(1);
 118   memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
 119   return(0);
 120 }
 121 
 122 
 123 /* Add an ARP entry for a host on this interface. */
 124 void
 125 eth_add_arp(unsigned long addr, struct sk_buff *skb, struct device *dev)
     /*  */
 126 {
 127   struct ethhdr *eth;
 128 
 129   eth = (struct ethhdr *) (skb + 1);
 130   arp_add(addr, eth->h_source, dev);
 131 }
 132 
 133 
 134 /* Determine the packet's protocol ID. */
 135 unsigned short
 136 eth_type_trans(struct sk_buff *skb, struct device *dev)
     /*  */
 137 {
 138   struct ethhdr *eth;
 139 
 140   eth = (struct ethhdr *) (skb + 1);
 141   return(eth->h_proto);
 142 }

/* */