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 #include <config.h> 25 26 #include "netdissect-stdinc.h" 27 28 #define ND_LONGJMP_FROM_TCHECK 29 #include "netdissect.h" 30 #include "extract.h" 31 #include "af.h" 32 33 34 /* 35 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order 36 * 32-bit integer that specifies the family, e.g. AF_INET. 37 * 38 * Note here that "host" refers to the host on which the packets were 39 * captured; that isn't necessarily *this* host. 40 * 41 * The OpenBSD DLT_LOOP packet header is the same, except that the integer 42 * is in network byte order. 43 */ 44 #define NULL_HDRLEN 4 45 46 /* 47 * Byte-swap a 32-bit number. 48 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on 49 * big-endian platforms.) 50 */ 51 #define SWAPLONG(y) \ 52 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff)) 53 54 static void 55 null_hdr_print(netdissect_options *ndo, uint32_t family, u_int length) 56 { 57 if (!ndo->ndo_qflag) { 58 ND_PRINT("AF %s (%u)", 59 tok2str(bsd_af_values,"Unknown",family),family); 60 } else { 61 ND_PRINT("%s", 62 tok2str(bsd_af_values,"Unknown AF %u",family)); 63 } 64 65 ND_PRINT(", length %u: ", length); 66 } 67 68 /* 69 * This is the top level routine of the printer. 'p' points 70 * to the ether header of the packet, 'h->ts' is the timestamp, 71 * 'h->len' is the length of the packet off the wire, and 'h->caplen' 72 * is the number of bytes actually captured. 73 */ 74 void 75 null_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) 76 { 77 u_int length = h->len; 78 u_int caplen = h->caplen; 79 uint32_t family; 80 81 ndo->ndo_protocol = "null"; 82 ND_TCHECK_LEN(p, NULL_HDRLEN); 83 ndo->ndo_ll_hdr_len += NULL_HDRLEN; 84 85 family = GET_HE_U_4(p); 86 87 /* 88 * This isn't necessarily in our host byte order; if this is 89 * a DLT_LOOP capture, it's in network byte order, and if 90 * this is a DLT_NULL capture from a machine with the opposite 91 * byte-order, it's in the opposite byte order from ours. 92 * 93 * If the upper 16 bits aren't all zero, assume it's byte-swapped. 94 */ 95 if ((family & 0xFFFF0000) != 0) 96 family = SWAPLONG(family); 97 98 if (ndo->ndo_eflag) 99 null_hdr_print(ndo, family, length); 100 101 length -= NULL_HDRLEN; 102 caplen -= NULL_HDRLEN; 103 p += NULL_HDRLEN; 104 105 switch (family) { 106 107 case BSD_AFNUM_INET: 108 ip_print(ndo, p, length); 109 break; 110 111 case BSD_AFNUM_INET6_BSD: 112 case BSD_AFNUM_INET6_FREEBSD: 113 case BSD_AFNUM_INET6_DARWIN: 114 ip6_print(ndo, p, length); 115 break; 116 117 case BSD_AFNUM_ISO: 118 isoclns_print(ndo, p, length); 119 break; 120 121 case BSD_AFNUM_APPLETALK: 122 atalk_print(ndo, p, length); 123 break; 124 125 case BSD_AFNUM_IPX: 126 ipx_print(ndo, p, length); 127 break; 128 129 default: 130 /* unknown AF_ value */ 131 if (!ndo->ndo_eflag) 132 null_hdr_print(ndo, family, length + NULL_HDRLEN); 133 if (!ndo->ndo_suppress_default_print) 134 ND_DEFAULTPRINT(p, caplen); 135 } 136 } 137