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 1.10 2024/09/02 16:15:32 christos Exp $"); 25 #endif 26 27 /* \summary: BSD loopback device printer */ 28 29 #include <config.h> 30 31 #include "netdissect-stdinc.h" 32 33 #define ND_LONGJMP_FROM_TCHECK 34 #include "netdissect.h" 35 #include "extract.h" 36 #include "af.h" 37 38 39 /* 40 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order 41 * 32-bit integer that specifies the family, e.g. AF_INET. 42 * 43 * Note here that "host" refers to the host on which the packets were 44 * captured; that isn't necessarily *this* host. 45 * 46 * The OpenBSD DLT_LOOP packet header is the same, except that the integer 47 * is in network byte order. 48 */ 49 #define NULL_HDRLEN 4 50 51 /* 52 * Byte-swap a 32-bit number. 53 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on 54 * big-endian platforms.) 55 */ 56 #define SWAPLONG(y) \ 57 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff)) 58 59 static void 60 null_hdr_print(netdissect_options *ndo, uint32_t family, u_int length) 61 { 62 if (!ndo->ndo_qflag) { 63 ND_PRINT("AF %s (%u)", 64 tok2str(bsd_af_values,"Unknown",family),family); 65 } else { 66 ND_PRINT("%s", 67 tok2str(bsd_af_values,"Unknown AF %u",family)); 68 } 69 70 ND_PRINT(", length %u: ", length); 71 } 72 73 /* 74 * This is the top level routine of the printer. 'p' points 75 * to the ether header of the packet, 'h->ts' is the timestamp, 76 * 'h->len' is the length of the packet off the wire, and 'h->caplen' 77 * is the number of bytes actually captured. 78 */ 79 void 80 null_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) 81 { 82 u_int length = h->len; 83 u_int caplen = h->caplen; 84 uint32_t family; 85 86 ndo->ndo_protocol = "null"; 87 ND_TCHECK_LEN(p, NULL_HDRLEN); 88 ndo->ndo_ll_hdr_len += NULL_HDRLEN; 89 90 family = GET_HE_U_4(p); 91 92 /* 93 * This isn't necessarily in our host byte order; if this is 94 * a DLT_LOOP capture, it's in network byte order, and if 95 * this is a DLT_NULL capture from a machine with the opposite 96 * byte-order, it's in the opposite byte order from ours. 97 * 98 * If the upper 16 bits aren't all zero, assume it's byte-swapped. 99 */ 100 if ((family & 0xFFFF0000) != 0) 101 family = SWAPLONG(family); 102 103 if (ndo->ndo_eflag) 104 null_hdr_print(ndo, family, length); 105 106 length -= NULL_HDRLEN; 107 caplen -= NULL_HDRLEN; 108 p += NULL_HDRLEN; 109 110 switch (family) { 111 112 case BSD_AFNUM_INET: 113 ip_print(ndo, p, length); 114 break; 115 116 case BSD_AFNUM_INET6_BSD: 117 case BSD_AFNUM_INET6_FREEBSD: 118 case BSD_AFNUM_INET6_DARWIN: 119 ip6_print(ndo, p, length); 120 break; 121 122 case BSD_AFNUM_ISO: 123 isoclns_print(ndo, p, length); 124 break; 125 126 case BSD_AFNUM_APPLETALK: 127 atalk_print(ndo, p, length); 128 break; 129 130 case BSD_AFNUM_IPX: 131 ipx_print(ndo, p, length); 132 break; 133 134 default: 135 /* unknown AF_ value */ 136 if (!ndo->ndo_eflag) 137 null_hdr_print(ndo, family, length + NULL_HDRLEN); 138 if (!ndo->ndo_suppress_default_print) 139 ND_DEFAULTPRINT(p, caplen); 140 } 141 } 142