Il CD di internet/CD.iso/SOURCE/KERNEL-S/V1.0/LINUX-1.0/LINUX-1/linux/net/inet/eth.c

C/C++ Source or Header | 1994-01-19 | 4.9 KB | 188 lines

/*
 * INET        An implementation of the TCP/IP protocol suite for the LINUX
 *        operating system.  INET is implemented using the  BSD Socket
 *        interface as the means of communication with the user level.
 *
 *        Ethernet-type device handling.
 *
 * Version:    @(#)eth.c    1.0.7    05/25/93
 *
 * Authors:    Ross Biro, <[e-mail]>
 *        Fred N. van Kempen, <[e-mail]>
 *        Mark Evans, <[e-mail]>
 *
 * Fixes:
 *        Mr Linux    : Arp problems
 *        Alan Cox    : Generic queue tidyup (very tiny here)
 *        Alan Cox    : eth_header ntohs should be htons
 *        Alan Cox    : eth_rebuild_header missing an htons and
 *                  minor other things.
 *        Tegge        : Arp bug fixes.
 *
 *        This program is free software; you can redistribute it and/or
 *        modify it under the terms of the GNU General Public License
 *        as published by the Free Software Foundation; either version
 *        2 of the License, or (at your option) any later version.
 */
#include <asm/segment.h>
#include <asm/system.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/in.h>
#include "inet.h"
#include "dev.h"
#include "eth.h"
#include "ip.h"
#include "route.h"
#include "protocol.h"
#include "tcp.h"
#include "skbuff.h"
#include "sock.h"
#include <linux/errno.h>
#include "arp.h"


/* Display an Ethernet address in readable format. */
char *eth_print(unsigned char *ptr)
{
  static char buff[64];

  if (ptr == NULL) return("[NONE]");
  sprintf(buff, "%02X:%02X:%02X:%02X:%02X:%02X",
    (ptr[0] & 255), (ptr[1] & 255), (ptr[2] & 255),
    (ptr[3] & 255), (ptr[4] & 255), (ptr[5] & 255)
  );
  return(buff);
}

void eth_setup(char *str, int *ints)
{
    struct device *d = dev_base;

    if (!str || !*str)
        return;
    while (d) {
        if (!strcmp(str,d->name)) {
            if (ints[0] > 0)
                d->irq=ints[1];
            if (ints[0] > 1)
                d->base_addr=ints[2];
            if (ints[0] > 2)
                d->mem_start=ints[3];
            if (ints[0] > 3)
                d->mem_end=ints[4];
            break;
        }
        d=d->next;
    }
}

/* Display the contents of the Ethernet MAC header. */
void
eth_dump(struct ethhdr *eth)
{
  if (inet_debug != DBG_ETH) return;

  printk("eth: SRC = %s ", eth_print(eth->h_source));
  printk("DST = %s ", eth_print(eth->h_dest));
  printk("TYPE = %04X\n", ntohs(eth->h_proto));
}


/* Create the Ethernet MAC header. */
int
eth_header(unsigned char *buff, struct device *dev, unsigned short type,
       unsigned long daddr, unsigned long saddr, unsigned len)
{
  struct ethhdr *eth;

  DPRINTF((DBG_DEV, "ETH: header(%s, ", in_ntoa(saddr)));
  DPRINTF((DBG_DEV, "%s, 0x%X)\n", in_ntoa(daddr), type));

  /* Fill in the basic Ethernet MAC header. */
  eth = (struct ethhdr *) buff;
  eth->h_proto = htons(type);

  /* We don't ARP for the LOOPBACK device... */
  if (dev->flags & IFF_LOOPBACK) {
    DPRINTF((DBG_DEV, "ETH: No header for loopback\n"));
    memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
    memset(eth->h_dest, 0, dev->addr_len);
    return(dev->hard_header_len);
  }

  /* Check if we can use the MAC BROADCAST address. */
  if (chk_addr(daddr) == IS_BROADCAST) {
    DPRINTF((DBG_DEV, "ETH: Using MAC Broadcast\n"));
    memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
    memcpy(eth->h_dest, dev->broadcast, dev->addr_len);
    return(dev->hard_header_len);
  }
  cli();
  memcpy(eth->h_source, &saddr, 4);
  /* No. Ask ARP to resolve the Ethernet address. */
  if (arp_find(eth->h_dest, daddr, dev, dev->pa_addr))
  {
        sti();
        if(type!=ETH_P_IP)
            printk("Erk: protocol %X got into an arp request state!\n",type);
    return(-dev->hard_header_len);
  }
  else
  {
      memcpy(eth->h_source,dev->dev_addr,dev->addr_len);    /* This was missing causing chaos if the
                                     header built correctly! */
      sti();
      return(dev->hard_header_len);
  }
}


/* Rebuild the Ethernet MAC header. */
int
eth_rebuild_header(void *buff, struct device *dev)
{
  struct ethhdr *eth;
  unsigned long src, dst;

  DPRINTF((DBG_DEV, "ETH: Using MAC Broadcast\n"));
  eth = (struct ethhdr *) buff;
  src = *(unsigned long *) eth->h_source;
  dst = *(unsigned long *) eth->h_dest;
  DPRINTF((DBG_DEV, "ETH: RebuildHeader: SRC=%s ", in_ntoa(src)));
  DPRINTF((DBG_DEV, "DST=%s\n", in_ntoa(dst)));
  if(eth->h_proto!=htons(ETH_P_ARP))    /* This ntohs kind of helps a bit! */
      if (arp_find(eth->h_dest, dst, dev, dev->pa_addr /* src */)) return(1);
  memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
  return(0);
}


/* Add an ARP entry for a host on this interface. */
void
eth_add_arp(unsigned long addr, struct sk_buff *skb, struct device *dev)
{
  struct ethhdr *eth;

  eth = (struct ethhdr *) skb->data;
  arp_add(addr, eth->h_source, dev);
}


/* Determine the packet's protocol ID. */
unsigned short
eth_type_trans(struct sk_buff *skb, struct device *dev)
{
  struct ethhdr *eth;

  eth = (struct ethhdr *) skb->data;

  if(ntohs(eth->h_proto)<1536)
      return(htons(ETH_P_802_3));
  return(eth->h_proto);
}