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 #include <sys/cdefs.h> 23 #ifndef lint 24 __RCSID("$NetBSD: print-null.c,v 1.9 2023/08/17 20:19:40 christos Exp $"); 25 #endif 26 27 /* \summary: BSD loopback device printer */ 28 29 #ifdef HAVE_CONFIG_H 30 #include <config.h> 31 #endif 32 33 #include "netdissect-stdinc.h" 34 35 #define ND_LONGJMP_FROM_TCHECK 36 #include "netdissect.h" 37 #include "extract.h" 38 #include "af.h" 39 40 41 /* 42 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order 43 * 32-bit integer that specifies the family, e.g. AF_INET. 44 * 45 * Note here that "host" refers to the host on which the packets were 46 * captured; that isn't necessarily *this* host. 47 * 48 * The OpenBSD DLT_LOOP packet header is the same, except that the integer 49 * is in network byte order. 50 */ 51 #define NULL_HDRLEN 4 52 53 /* 54 * Byte-swap a 32-bit number. 55 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on 56 * big-endian platforms.) 57 */ 58 #define SWAPLONG(y) \ 59 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff)) 60 61 static void 62 null_hdr_print(netdissect_options *ndo, uint32_t family, u_int length) 63 { 64 if (!ndo->ndo_qflag) { 65 ND_PRINT("AF %s (%u)", 66 tok2str(bsd_af_values,"Unknown",family),family); 67 } else { 68 ND_PRINT("%s", 69 tok2str(bsd_af_values,"Unknown AF %u",family)); 70 } 71 72 ND_PRINT(", length %u: ", length); 73 } 74 75 /* 76 * This is the top level routine of the printer. 'p' points 77 * to the ether header of the packet, 'h->ts' is the timestamp, 78 * 'h->len' is the length of the packet off the wire, and 'h->caplen' 79 * is the number of bytes actually captured. 80 */ 81 void 82 null_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) 83 { 84 u_int length = h->len; 85 u_int caplen = h->caplen; 86 uint32_t family; 87 88 ndo->ndo_protocol = "null"; 89 ND_TCHECK_LEN(p, NULL_HDRLEN); 90 ndo->ndo_ll_hdr_len += NULL_HDRLEN; 91 92 family = GET_HE_U_4(p); 93 94 /* 95 * This isn't necessarily in our host byte order; if this is 96 * a DLT_LOOP capture, it's in network byte order, and if 97 * this is a DLT_NULL capture from a machine with the opposite 98 * byte-order, it's in the opposite byte order from ours. 99 * 100 * If the upper 16 bits aren't all zero, assume it's byte-swapped. 101 */ 102 if ((family & 0xFFFF0000) != 0) 103 family = SWAPLONG(family); 104 105 if (ndo->ndo_eflag) 106 null_hdr_print(ndo, family, length); 107 108 length -= NULL_HDRLEN; 109 caplen -= NULL_HDRLEN; 110 p += NULL_HDRLEN; 111 112 switch (family) { 113 114 case BSD_AFNUM_INET: 115 ip_print(ndo, p, length); 116 break; 117 118 case BSD_AFNUM_INET6_BSD: 119 case BSD_AFNUM_INET6_FREEBSD: 120 case BSD_AFNUM_INET6_DARWIN: 121 ip6_print(ndo, p, length); 122 break; 123 124 case BSD_AFNUM_ISO: 125 isoclns_print(ndo, p, length); 126 break; 127 128 case BSD_AFNUM_APPLETALK: 129 atalk_print(ndo, p, length); 130 break; 131 132 case BSD_AFNUM_IPX: 133 ipx_print(ndo, p, length); 134 break; 135 136 default: 137 /* unknown AF_ value */ 138 if (!ndo->ndo_eflag) 139 null_hdr_print(ndo, family, length + NULL_HDRLEN); 140 if (!ndo->ndo_suppress_default_print) 141 ND_DEFAULTPRINT(p, caplen); 142 } 143 } 144