Create ether_ntohost.c

It's a major hassle to use 'pcap_next_etherent()' in Windump. So simply add a local 'ether_ntohost()' here.

diff --git a/win32/src/ether_ntohost.c b/win32/src/ether_ntohost.c
new file mode 100644 (file)
index 0000000..ae988f7
--- /dev/null
+++ b/win32/src/ether_ntohost.c
@@ -0,0 +1,219 @@
+/*
+ * 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 <[email protected]> 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, &eth[0], &eth[1], &eth[2], &eth[3], &eth[4], &eth[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,&eth))
+       continue;
+
+    e = calloc (sizeof(*e), 1);
+    if (!e)
+       break;
+
+    memcpy(&e->eth_addr, &eth, 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);
+}
+