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| | /* Origin NetBSD: src/lib/libc/net/ethers.c */
/*
* ethers(3N) a la Sun.
*
* Written by Roland McGrath <roland@frob.com> 10/14/93.
* Public domain.
*
* port for musl by Abdoulaye Walsimou GAYE <awg@embtoolkit.org> 2012/10/15
*/
#define _BSD_SOURCE
#include <net/ethernet.h>
#include <netinet/ether.h>
#include <sys/param.h>
#include <assert.h>
#include <errno.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef _PATH_ETHERS
#define _PATH_ETHERS "/etc/ethers"
#endif
/*
* ether_ntoa():
* This function converts this structure into an ASCII string of the form
* ``xx:xx:xx:xx:xx:xx'', consisting of 6 hexadecimal numbers separated
* by colons. It returns a pointer to a static buffer that is reused for
* each call.
*/
char *ether_ntoa(const struct ether_addr *e)
{
static char a[18];
assert(e != NULL);
(void) snprintf(a, sizeof a, "%02x:%02x:%02x:%02x:%02x:%02x",
e->ether_addr_octet[0], e->ether_addr_octet[1],
e->ether_addr_octet[2], e->ether_addr_octet[3],
e->ether_addr_octet[4], e->ether_addr_octet[5]);
return a;
}
/*
* ether_aton():
* This function converts an ASCII string of the same form and to a structure
* containing the 6 octets of the address. It returns a pointer to a
* static structure that is reused for each call.
*/
struct ether_addr *ether_aton(const char *s)
{
static struct ether_addr n;
unsigned int i[6];
assert(s != NULL);
if (sscanf(s, " %x:%x:%x:%x:%x:%x ", &i[0], &i[1],
&i[2], &i[3], &i[4], &i[5]) == 6) {
n.ether_addr_octet[0] = (unsigned char)i[0];
n.ether_addr_octet[1] = (unsigned char)i[1];
n.ether_addr_octet[2] = (unsigned char)i[2];
n.ether_addr_octet[3] = (unsigned char)i[3];
n.ether_addr_octet[4] = (unsigned char)i[4];
n.ether_addr_octet[5] = (unsigned char)i[5];
return &n;
}
return NULL;
}
/*
* ether_ntohost():
* This function interrogates the data base mapping host names to Ethernet
* addresses, /etc/ethers.
* It looks up the given Ethernet address and writes the associated host name
* into the character buffer passed.
* It returns zero if it finds the requested host name and -1 if not.
*/
int ether_ntohost(char *hostname, const struct ether_addr *e)
{
FILE *f;
char *p;
size_t len;
struct ether_addr try;
assert(hostname != NULL);
assert(e != NULL);
f = fopen(_PATH_ETHERS, "r");
if (f == NULL)
return -1;
while ((p = fgetln(f, &len)) != NULL) {
if (p[len - 1] != '\n')
continue; /* skip lines w/o \n */
p[--len] = '\0';
if (ether_line(p, &try, hostname) == 0 &&
memcmp(&try, e, sizeof try) == 0) {
(void)fclose(f);
return 0;
}
}
(void)fclose(f);
errno = ENOENT;
return -1;
}
/*
* ether_hostton():
* This function interrogates the data base mapping host names to Ethernet
* addresses, /etc/ethers.
* It looks up the given host name and writes the associated Ethernet address
* into the structure passed.
* It returns zero if it finds the requested address and -1 if not.
*/
int ether_hostton(const char *hostname, struct ether_addr *e)
{
FILE *f;
char *p;
size_t len;
char try[MAXHOSTNAMELEN + 1];
assert(hostname != NULL);
assert(e != NULL);
f = fopen(_PATH_ETHERS, "r");
if (f==NULL)
return -1;
while ((p = fgetln(f, &len)) != NULL) {
if (p[len - 1] != '\n')
continue; /* skip lines w/o \n */
p[--len] = '\0';
if (ether_line(p, e, try) == 0 && strcmp(hostname, try) == 0) {
(void)fclose(f);
return 0;
}
}
(void)fclose(f);
errno = ENOENT;
return -1;
}
/*
* ether_line():
* This function parses a line from the /etc/ethers file and fills in the passed
* ``struct ether_addr'' and character buffer with the Ethernet address and host
* name on the line.
* It returns zero if the line was successfully parsed and -1 if not.
*/
int ether_line(const char *l, struct ether_addr *e, char *hostname)
{
unsigned int i[6];
#define S2(arg) #arg
#define S1(arg) S2(arg)
static const char fmt[] = " %x:%x:%x:%x:%x:%x"
" %" S1(MAXHOSTNAMELEN) "s\n";
#undef S2
#undef S1
assert(l != NULL);
assert(e != NULL);
assert(hostname != NULL);
if (sscanf(l, fmt,
&i[0], &i[1], &i[2], &i[3], &i[4], &i[5], hostname) == 7) {
e->ether_addr_octet[0] = (unsigned char)i[0];
e->ether_addr_octet[1] = (unsigned char)i[1];
e->ether_addr_octet[2] = (unsigned char)i[2];
e->ether_addr_octet[3] = (unsigned char)i[3];
e->ether_addr_octet[4] = (unsigned char)i[4];
e->ether_addr_octet[5] = (unsigned char)i[5];
return 0;
}
errno = EINVAL;
return -1;
}
|