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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 /* \summary: Classical-IP over ATM printer */
     24 
     25 #ifdef HAVE_CONFIG_H
     26 #include "config.h"
     27 #endif
     28 
     29 #include <string.h>
     30 
     31 #include <netdissect-stdinc.h>
     32 
     33 #include "netdissect.h"
     34 #include "addrtoname.h"
     35 
     36 static const unsigned char rfcllc[] = {
     37 	0xaa,	/* DSAP: non-ISO */
     38 	0xaa,	/* SSAP: non-ISO */
     39 	0x03,	/* Ctrl: Unnumbered Information Command PDU */
     40 	0x00,	/* OUI: EtherType */
     41 	0x00,
     42 	0x00 };
     43 
     44 static inline void
     45 cip_print(netdissect_options *ndo, u_int length)
     46 {
     47 	/*
     48 	 * There is no MAC-layer header, so just print the length.
     49 	 */
     50 	ND_PRINT((ndo, "%u: ", length));
     51 }
     52 
     53 /*
     54  * This is the top level routine of the printer.  'p' points
     55  * to the LLC/SNAP or raw header of the packet, 'h->ts' is the timestamp,
     56  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
     57  * is the number of bytes actually captured.
     58  */
     59 u_int
     60 cip_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
     61 {
     62 	u_int caplen = h->caplen;
     63 	u_int length = h->len;
     64 	size_t cmplen;
     65 	int llc_hdrlen;
     66 
     67 	cmplen = sizeof(rfcllc);
     68 	if (cmplen > caplen)
     69 		cmplen = caplen;
     70 	if (cmplen > length)
     71 		cmplen = length;
     72 
     73 	if (ndo->ndo_eflag)
     74 		cip_print(ndo, length);
     75 
     76 	if (cmplen == 0) {
     77 		ND_PRINT((ndo, "[|cip]"));
     78 		return 0;
     79 	}
     80 	if (memcmp(rfcllc, p, cmplen) == 0) {
     81 		/*
     82 		 * LLC header is present.  Try to print it & higher layers.
     83 		 */
     84 		llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
     85 		if (llc_hdrlen < 0) {
     86 			/* packet type not known, print raw packet */
     87 			if (!ndo->ndo_suppress_default_print)
     88 				ND_DEFAULTPRINT(p, caplen);
     89 			llc_hdrlen = -llc_hdrlen;
     90 		}
     91 	} else {
     92 		/*
     93 		 * LLC header is absent; treat it as just IP.
     94 		 */
     95 		llc_hdrlen = 0;
     96 		ip_print(ndo, p, length);
     97 	}
     98 
     99 	return (llc_hdrlen);
    100 }
    101 
    102 
    103 /*
    104  * Local Variables:
    105  * c-style: whitesmith
    106  * c-basic-offset: 8
    107  * End:
    108  */
    109