diff options
Diffstat (limited to 'tcpdump-stdinc.h')
| -rw-r--r-- | tcpdump-stdinc.h | 39 |
1 files changed, 36 insertions, 3 deletions
diff --git a/tcpdump-stdinc.h b/tcpdump-stdinc.h index c437cc1..d350d1b 100644 --- a/tcpdump-stdinc.h +++ b/tcpdump-stdinc.h @@ -131,10 +131,43 @@ typedef char* caddr_t; #endif /* WIN32 */ -#ifdef INET6 -#include "ip6.h" +#ifndef HAVE___ATTRIBUTE__ +#define __attribute__(x) #endif +/* + * Used to declare a structure unaligned, so that the C compiler, + * if necessary, generates code that doesn't assume alignment. + * This is required because there is no guarantee that the packet + * data we get from libpcap/WinPcap is properly aligned. + * + * This assumes that, for all compilers that support __attribute__: + * + * 1) they support __attribute__((packed)); + * + * 2) for all instruction set architectures requiring strict + * alignment, declaring a structure with that attribute + * causes the compiler to generate code that handles + * misaligned 2-byte, 4-byte, and 8-byte integral + * quantities. + * + * It does not (yet) handle compilers where you can get the compiler + * to generate code of that sort by some other means. + * + * This is required in order to, for example, keep the compiler from + * generating, for + * + * if (bp->bp_htype == 1 && bp->bp_hlen == 6 && bp->bp_op == BOOTPREQUEST) { + * + * in print-bootp.c, code that loads the first 4-byte word of a + * "struct bootp", masking out the bp_hops field, and comparing the result + * against 0x01010600. + * + * Note: this also requires that padding be put into the structure, + * at least for compilers where it's implemented as __attribute__((packed)). + */ +#define UNALIGNED __attribute__((packed)) + #if defined(WIN32) || defined(MSDOS) #define FOPEN_READ_TXT "rt" #define FOPEN_READ_BIN "rb" @@ -147,7 +180,7 @@ typedef char* caddr_t; #define FOPEN_WRITE_BIN FOPEN_WRITE_TXT #endif -#if defined(__GNUC__) && defined(__i386__) && !defined(__ntohl) +#if defined(__GNUC__) && defined(__i386__) && !defined(__APPLE__) && !defined(__ntohl) #undef ntohl #undef ntohs #undef htonl |
