ether.c

一个基于linux的TCP/IP协议栈的实现

/* ether.c
 * [e-mail]
 * 2006-10-20
 */

#include "config.h"

#include <sys/types.h>
#include <sys/socket.h>
#include <net/if_arp.h>
#include <linux/if_ether.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#include "net-support.h"
#include "pathnames.h"
#include "util.h"

extern struct hwtype ether_hwtype;

static char *pr_ether(unsigned char *ptr)
{
	static char buff[64];

	snprintf(buff, sizeof(buff), "%02X:%02X:%02X:%02X:%02X:%02X",
					(ptr[0] & 0377), (ptr[1] & 0377), (ptr[2] & 0377),
					(ptr[3] & 0377), (ptr[4] & 0377), (ptr[5] & 0377)
			);
	return (buff);
}

static int in_ether(char *bufp, struct sockaddr *sap)
{
	unsigned char *ptr;
	char c, *orig;
	int i;
	unsigned val;

	sap->sa_family = ether_hwtype.type;
	ptr = (unsigned char *)sap->sa_data;

	i = 0;
	orig = bufp;
	while ((*bufp != '\0') && (i < ETH_ALEN)) {
		val = 0;
		c = *bufp++;
		if (isdigit(c))
				val = c - '0';
		else if (c >= 'a' && c <= 'f')
				val = c - 'a' + 10;
		else if (c >= 'A' && c <= 'F')
				val = c - 'A' + 10;
		else{
			fprintf(stderr, "in_ether(%s): invalid ether address!\n", orig);
			errno = EINVAL;
			return (-1);
		}
		val <<= 4;
		c = *bufp;
		if( isdigit(c) )
			val |= c - '0';
		else if( c >= 'a' && c <= 'f' )
			val |= c - 'a' + 10;
		else if( c >= 'A' && c <= 'F' )
			val |= c - 'A' + 10;
		else if( c == ':' || c == 0 )
				val >>= 4;
		else{
			fprintf(stderr, "in_ether(%s): invalid ether address!\n", orig);
			errno = EINVAL;
			return (-1);
		}
		if( c != 0 )
			bufp++;
		*ptr++ = (unsigned char) (val & 0377);
		i++;

		if (*bufp == ':') {
			if (i == ETH_ALEN) {
				fprintf(stderr, "in_ether(%s): trailing : ignored!\n", orig);
			}
			bufp++;
		}
	}
	return (0);
}


struct hwtype ether_hwtype =
{
	"ether", NULL, /*"10Mbps Ethernet", */ ARPHRD_ETHER, ETH_ALEN,
	pr_ether, in_ether, NULL
};