1 /* 2 * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 */ 21 22 /* \summary: BSD loopback device printer */ 23 24 #ifdef HAVE_CONFIG_H 25 #include <config.h> 26 #endif 27 28 #include "netdissect-stdinc.h" 29 30 #define ND_LONGJMP_FROM_TCHECK 31 #include "netdissect.h" 32 #include "extract.h" 33 #include "af.h" 34 35 36 /* 37 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order 38 * 32-bit integer that specifies the family, e.g. AF_INET. 39 * 40 * Note here that "host" refers to the host on which the packets were 41 * captured; that isn't necessarily *this* host. 42 * 43 * The OpenBSD DLT_LOOP packet header is the same, except that the integer 44 * is in network byte order. 45 */ 46 #define NULL_HDRLEN 4 47 48 /* 49 * Byte-swap a 32-bit number. 50 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on 51 * big-endian platforms.) 52 */ 53 #define SWAPLONG(y) \ 54 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff)) 55 56 static void 57 null_hdr_print(netdissect_options *ndo, uint32_t family, u_int length) 58 { 59 if (!ndo->ndo_qflag) { 60 ND_PRINT("AF %s (%u)", 61 tok2str(bsd_af_values,"Unknown",family),family); 62 } else { 63 ND_PRINT("%s", 64 tok2str(bsd_af_values,"Unknown AF %u",family)); 65 } 66 67 ND_PRINT(", length %u: ", length); 68 } 69 70 /* 71 * This is the top level routine of the printer. 'p' points 72 * to the ether header of the packet, 'h->ts' is the timestamp, 73 * 'h->len' is the length of the packet off the wire, and 'h->caplen' 74 * is the number of bytes actually captured. 75 */ 76 void 77 null_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) 78 { 79 u_int length = h->len; 80 u_int caplen = h->caplen; 81 uint32_t family; 82 83 ndo->ndo_protocol = "null"; 84 ND_TCHECK_LEN(p, NULL_HDRLEN); 85 ndo->ndo_ll_hdr_len += NULL_HDRLEN; 86 87 family = GET_HE_U_4(p); 88 89 /* 90 * This isn't necessarily in our host byte order; if this is 91 * a DLT_LOOP capture, it's in network byte order, and if 92 * this is a DLT_NULL capture from a machine with the opposite 93 * byte-order, it's in the opposite byte order from ours. 94 * 95 * If the upper 16 bits aren't all zero, assume it's byte-swapped. 96 */ 97 if ((family & 0xFFFF0000) != 0) 98 family = SWAPLONG(family); 99 100 if (ndo->ndo_eflag) 101 null_hdr_print(ndo, family, length); 102 103 length -= NULL_HDRLEN; 104 caplen -= NULL_HDRLEN; 105 p += NULL_HDRLEN; 106 107 switch (family) { 108 109 case BSD_AFNUM_INET: 110 ip_print(ndo, p, length); 111 break; 112 113 case BSD_AFNUM_INET6_BSD: 114 case BSD_AFNUM_INET6_FREEBSD: 115 case BSD_AFNUM_INET6_DARWIN: 116 ip6_print(ndo, p, length); 117 break; 118 119 case BSD_AFNUM_ISO: 120 isoclns_print(ndo, p, length); 121 break; 122 123 case BSD_AFNUM_APPLETALK: 124 atalk_print(ndo, p, length); 125 break; 126 127 case BSD_AFNUM_IPX: 128 ipx_print(ndo, p, length); 129 break; 130 131 default: 132 /* unknown AF_ value */ 133 if (!ndo->ndo_eflag) 134 null_hdr_print(ndo, family, length + NULL_HDRLEN); 135 if (!ndo->ndo_suppress_default_print) 136 ND_DEFAULTPRINT(p, caplen); 137 } 138 } 139