print cisco cdp packets, from Gert Doering <[email protected]>

diff --git a/print-cdp.c b/print-cdp.c
new file mode 100644 (file)
index 0000000..7f1ff60
--- /dev/null
+++ b/print-cdp.c
@@ -0,0 +1,160 @@
+/*
+ * Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
+ *     The Regents of the University of California.  All rights reserved.
+ *
+ * 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.
+ *
+ * Code by Gert Doering, SpaceNet GmbH, [email protected]
+ *
+ * Reference documentation:
+ *    http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm
+ */
+
+#ifndef lint
+static const char rcsid[] =
+    "@(#) $Header: /tcpdump/master/tcpdump/print-cdp.c,v 1.1 2000-05-15 00:41:06 assar Exp $";
+#endif
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <sys/param.h>
+#include <sys/time.h>
+
+#include <netinet/in.h>
+
+#include <ctype.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "interface.h"
+#include "addrtoname.h"
+#include "extract.h"                   /* must come after interface.h */
+
+static void cdp_print_addr( const u_char * p, int l );
+
+/*
+ * Returns non-zero IFF it succeeds in printing the header
+ */
+void
+cdp_print(const u_char *p, u_int length, u_int caplen,
+         const u_char *esrc, const u_char *edst)
+{
+       int i;
+       int type, len;
+
+       /* Cisco Discovery Protocol */
+
+
+       if ( caplen < 12 ) {
+               (void)printf("[|cdp]");
+               return;
+       }
+
+       i=8;            /* CDP data starts at offset 8 */
+       printf ("CDP v%d, ttl=%ds", p[i], p[i+1] );
+       i+=4;           /* skip version, TTL and chksum */
+
+       while (i < length) {
+           if ( i+4 > caplen ) {
+               printf("[!cdp]");
+               return;
+           }
+           type = (p[i]<<8) + p[i+1];
+           len  = (p[i+2]<<8) + p[i+3];
+
+           if ( vflag )
+               printf( "\n\t%02x/%02x", type, len );
+           else
+               printf( "\n\t" );
+
+           if ( i+len > caplen ) {
+               printf("[!cdp]");
+               return;
+           }
+
+           switch( type )
+           {
+           case 0x01:
+               printf( " DevID '%.*s'", len-4, p+i+4 );
+               break;
+           case 0x02:
+               printf( " Addr" );
+               cdp_print_addr( p+i+4, len-4 );
+               break;
+           case 0x03:
+               printf( " PortID '%.*s'", len-4, p+i+4 );
+               break;
+           case 0x04:
+               printf( " CAP 0x%02x", (unsigned) p[i+7] );
+               break;
+           case 0x05:
+               if ( vflag )
+                   printf( " Version:\n%.*s", len-4, p+i+4 );
+               else
+                   printf( " Version: (suppressed)" );
+               break;
+           case 0x06:
+               printf( " Platform: '%.*s'", len-4, p+i+4 );
+               break;
+           default:
+               printf( " unknown field type %02x, len %d", 
+                       type, len );
+           }
+           i+=len;
+
+       }
+}
+
+static void
+cdp_print_addr( const u_char * p, int l )
+{
+       int pl, al, num;
+       const u_char * endp = p+l;
+
+       num = (p[0] << 24) + (p[1]<<16) + (p[2]<<8)+ p[3];
+       p+=4;
+
+       printf(" (%d): ", num );
+
+       while( p < endp && num >= 0) {
+               pl=*(p+1);
+               p+=2; 
+
+               /* special case: IPv4, protocol type=0xcc, addr. length=4 */
+               if ( pl == 1 && *p == 0xcc && 
+                    p[1] == 0 && p[2] == 4 ) {
+                       p+=3;
+
+                       printf( "IPv4 %d.%d.%d.%d ", p[0], p[1], p[2], p[3] );
+                       p+=4;
+               } else {        /* generic case: just print raw data */
+                       printf("pt=0x%02x, pl=%d, pb=", *(p-2), pl);
+                       while( pl-- > 0 )
+                               printf( " %02x", *p++);
+                       al=(*p << 8) + *(p+1);
+                       printf( ", al=%d, a=", al );
+                       p+=2; 
+                       while( al-- > 0 )
+                               printf( " %02x", *p++);
+               }
+               printf("  ");
+               num--;
+       }
+}