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      1 /*
      2  * Marko Kiiskila carnil (at) cs.tut.fi
      3  *
      4  * Tampere University of Technology - Telecommunications Laboratory
      5  *
      6  * Permission to use, copy, modify and distribute this
      7  * software and its documentation is hereby granted,
      8  * provided that both the copyright notice and this
      9  * permission notice appear in all copies of the software,
     10  * derivative works or modified versions, and any portions
     11  * thereof, that both notices appear in supporting
     12  * documentation, and that the use of this software is
     13  * acknowledged in any publications resulting from using
     14  * the software.
     15  *
     16  * TUT ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     17  * CONDITION AND DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     18  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS
     19  * SOFTWARE.
     20  *
     21  */
     22 
     23 #define NETDISSECT_REWORKED
     24 #ifdef HAVE_CONFIG_H
     25 #include "config.h"
     26 #endif
     27 
     28 #include <string.h>
     29 
     30 #include <tcpdump-stdinc.h>
     31 
     32 #include "interface.h"
     33 #include "addrtoname.h"
     34 
     35 #define RFC1483LLC_LEN	8
     36 
     37 static const unsigned char rfcllc[] = {
     38 	0xaa,	/* DSAP: non-ISO */
     39 	0xaa,	/* SSAP: non-ISO */
     40 	0x03,	/* Ctrl: Unnumbered Information Command PDU */
     41 	0x00,	/* OUI: EtherType */
     42 	0x00,
     43 	0x00 };
     44 
     45 static inline void
     46 cip_print(netdissect_options *ndo, int length)
     47 {
     48 	/*
     49 	 * There is no MAC-layer header, so just print the length.
     50 	 */
     51 	ND_PRINT((ndo, "%d: ", length));
     52 }
     53 
     54 /*
     55  * This is the top level routine of the printer.  'p' points
     56  * to the LLC/SNAP or raw header of the packet, 'h->ts' is the timestamp,
     57  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
     58  * is the number of bytes actually captured.
     59  */
     60 u_int
     61 cip_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
     62 {
     63 	u_int caplen = h->caplen;
     64 	u_int length = h->len;
     65 	u_short extracted_ethertype;
     66 
     67 	if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
     68 		ND_PRINT((ndo, "[|cip]"));
     69 		return (0);
     70 	}
     71 
     72 	if (ndo->ndo_eflag)
     73 		cip_print(ndo, length);
     74 
     75 	if (memcmp(rfcllc, p, sizeof(rfcllc)) == 0) {
     76 		/*
     77 		 * LLC header is present.  Try to print it & higher layers.
     78 		 */
     79 		if (llc_print(ndo, p, length, caplen, NULL, NULL,
     80 		    &extracted_ethertype) == 0) {
     81 			/* ether_type not known, print raw packet */
     82 			if (!ndo->ndo_eflag)
     83 				cip_print(ndo, length);
     84 			if (extracted_ethertype) {
     85 				ND_PRINT((ndo, "(LLC %s) ",
     86 			       etherproto_string(htons(extracted_ethertype))));
     87 			}
     88 			if (!ndo->ndo_suppress_default_print)
     89 				ND_DEFAULTPRINT(p, caplen);
     90 		}
     91 	} else {
     92 		/*
     93 		 * LLC header is absent; treat it as just IP.
     94 		 */
     95 		ip_print(ndo, p, length);
     96 	}
     97 
     98 	return (0);
     99 }
    100 
    101 
    102 /*
    103  * Local Variables:
    104  * c-style: whitesmith
    105  * c-basic-offset: 8
    106  * End:
    107  */
    108