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/*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* tcpdump/Win32 functions for reading and parsing system's Ethernet
* address file:
* '%SystemRoot%/drivers/etc/ethers' (Win-NT+)
* or '%Windir%/etc/ethers' (Win-9x/ME)
*
* G. Vanem <gvanem@yahoo.no> 2012.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <tcpdump-stdinc.h>
#include "ether.h"
#include "interface.h"
#include "addrtoname.h"
typedef struct ether_addr {
unsigned char octet[ETHER_ADDR_LEN];
} ether_address;
typedef struct ether_entry {
ether_address eth_addr; /* MAC address */
char *name; /* name of MAC-address */
struct ether_entry *next;
} ether_entry;
static struct ether_entry *eth0 = NULL;
/*
* The reason to avoid using 'pcap_next_etherent()' in addrtoname.c
* are several:
* 1) wpcap.dll and 'pcap_next_etherent()' could have been built in
* debug-mode (-MDd) or release-mode (-MD) and tcpdump in
* the opposite model.
* 2) If this is built by MSVC, wpcap.dll could have been built by
* MingW. It has no debug-model.
* 3) It may not have been exported from wpcap.dll (present in wpcap.def).
*
* So we shoe-horn the building of tcpdump with '-DUSE_ETHER_NTOHOST' to
* make 'init_etherarray()' call the below 'ether_ntohost()' instead.
*/
#if !defined(USE_ETHER_NTOHOST)
#error "'-DUSE_ETHER_NTOHOST' must be set"
#endif
/*
* Return TRUE if running under Win-95/98/ME.
*/
static BOOL is_win9x (void)
{
OSVERSIONINFO ovi;
DWORD os_ver = GetVersion();
DWORD major_ver = LOBYTE (LOWORD(os_ver));
return (os_ver >= 0x80000000 && major_ver >= 4);
}
/*
* Return path to "%SystemRoot%/drivers/etc/<file>" (Win-NT+)
* or to "%Windir%/etc/<file>" (Win-9x/ME)
*/
const char *etc_path (const char *file)
{
BOOL win9x = is_win9x();
const char *env = win9x ? getenv("WinDir") : getenv("SystemRoot");
static char path[MAX_PATH];
if (!env)
return (file);
if (win9x)
snprintf (path, sizeof(path), "%s\\etc\\%s", env, file);
else
snprintf (path, sizeof(path), "%s\\system32\\drivers\\etc\\%s", env, file);
return (path);
}
/*
* Parse a string-buf containing an MAC address and name.
* Accepts MAC addresses on both "xx:xx:xx.." and "xx-xx-xx.." forms.
*
* We could have used pcap_ether_aton(), but problem 3) above could apply.
* or we could have cut & pasted 'pcap_next_etherent(FILE *fp)' below.
*/
#define MIN_LEN sizeof("0:0:0:0:0:0 X")
static
int parse_ether_buf (const char *buf, char **result, struct ether_addr *e)
{
const char *fmt;
char *name;
char *str = (char*)buf;
unsigned eth [sizeof(*e)];
int i;
/* Find first non-blank in 'buf' */
while (str[0] && str[1] && isspace((int)str[0]))
str++;
if (*str == '#' || *str == ';' || *str == '\n' || strlen(str) < MIN_LEN)
return (0);
if (str[2] == ':')
fmt = "%02x:%02x:%02x:%02x:%02x:%02x";
else
fmt = "%02x-%02x-%02x-%02x-%02x-%02x";
if (sscanf(str, fmt, ð[0], ð[1], ð[2], ð[3], ð[4], ð[5]) != ETHER_ADDR_LEN)
return (0);
str = strtok (str, " \t");
name = strtok (NULL, " #\t\n");
if (!str || !name || strlen(name) < 1)
return (0);
*result = name;
for (i = 0; i < ETHER_ADDR_LEN; i++)
e->octet[i] = eth[i];
return (1);
}
static void free_ethers (void)
{
struct ether_entry *e, *next;
for (e = eth0; e; e = next) {
next = e->next;
free(e->name);
free(e);
}
eth0 = NULL;
}
static int init_ethers (void)
{
char buf[BUFSIZE];
FILE *fp = fopen (etc_path("ethers"), "r");
if (!fp)
return (0);
while (fgets(buf,sizeof(buf),fp))
{
struct ether_entry *e;
char *name;
ether_address eth;
if (!parse_ether_buf(buf,&name,ð))
continue;
e = calloc (sizeof(*e), 1);
if (!e)
break;
memcpy(&e->eth_addr, ð, ETHER_ADDR_LEN);
e->name = strdup(name);
if (!e->name) {
free(e);
break;
}
e->next = eth0;
eth0 = e;
}
fclose(fp);
atexit(free_ethers);
return (1);
}
/*
* Map an ethernet address 'e' to a 'name'.
* Returns 0 on success.
*
* This function is called at startup by init_etherarray() and then
* by etheraddr_string() as needed. To avoid doing an expensive fopen()
* on each call, the contents of 'etc_path("ethers")' is cached here in
* a linked-list 'eth0'.
*/
int ether_ntohost (char *name, struct ether_addr *e)
{
const struct ether_entry *cache;
static int init = 0;
if (!init) {
init_ethers();
init = 1;
}
for (cache = eth0; cache; cache = cache->next)
if (!memcmp(&e->octet, &cache->eth_addr, ETHER_ADDR_LEN)) {
strcpy (name,cache->name);
return (0);
}
return (1);
}
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