Don't require IPv6 library support in order to support IPv6 addresses.

Have our own routines to convert between IPv4/IPv6 addresses and
strings; that helps if, for example, we want to build binary versions of
tcpdump for Windows that can run both on NT 5 (W2K/WXP), which doesn't
have inet_ntop() or inet_pton(), and NT 6 (Vista/7/8/10), which do.  It
also means that we don't require IPv6 library support on UN*X to print
addresses (if somebody wants to build tcpdump for older UN*Xes lacking
IPv6 support in the system library or in add-on libraries).

Get rid of files in the missing directory that we don't need, and
various no-longer-necessary autoconf tests.

1 files changed, 45 insertions, 6 deletions

diff --git a/netdissect-stdinc.h b/netdissect-stdinc.h
index 093fc092..44967852 100644
--- a/netdissect-stdinc.h
+++ b/netdissect-stdinc.h
@@ -43,6 +43,10 @@
 
 #ifdef _WIN32
 
+/*
+ * Includes and definitions for Windows.
+ */
+
 #include <stdint.h>
 #include <stdio.h>
 #include <winsock2.h>
@@ -142,11 +146,6 @@
 #define O_RDONLY _O_RDONLY
 #endif  /* _MSC_VER */
 
-/* Protos for missing/x.c functions (ideally <missing/addrinfo.h>
- * should be used, but it clashes with <ws2tcpip.h>).
- */
-extern const char *inet_ntop (int, const void *, char *, size_t);
-extern int inet_pton (int, const char *, void *);
 extern int inet_aton (const char *cp, struct in_addr *addr);
 
 /*
@@ -171,13 +170,16 @@ typedef char* caddr_t;
 #endif /* caddr_t */
 
 #define MAXHOSTNAMELEN	64
-#define	NI_MAXHOST	1025
 #define snprintf _snprintf
 #define vsnprintf _vsnprintf
 #define RETSIGTYPE void
 
 #else /* _WIN32 */
 
+/*
+ * Includes and definitions for various flavors of UN*X.
+ */
+
 #include <ctype.h>
 #include <unistd.h>
 #include <netdb.h>
@@ -241,6 +243,9 @@ typedef char* caddr_t;
 #define UNALIGNED	__attribute__((packed))
 #endif
 
+/*
+ * fopen() read and write modes for text files and binary files.
+ */
 #if defined(_WIN32) || defined(MSDOS)
   #define FOPEN_READ_TXT   "rt"
   #define FOPEN_READ_BIN   "rb"
@@ -253,6 +258,16 @@ typedef char* caddr_t;
   #define FOPEN_WRITE_BIN  FOPEN_WRITE_TXT
 #endif
 
+/*
+ * Inline x86 assembler-language versions of ntoh[ls]() and hton[ls](),
+ * defined if the OS doesn't provide them.  These assume no more than
+ * an 80386, so, for example, it avoids the bswap instruction added in
+ * the 80486.
+ *
+ * (We don't use them on OS X; Apple provides their own, which *doesn't*
+ * avoid the bswap instruction, as OS X only supports machines that
+ * have it.)
+ */
 #if defined(__GNUC__) && defined(__i386__) && !defined(__APPLE__) && !defined(__ntohl)
   #undef ntohl
   #undef ntohs
@@ -284,6 +299,30 @@ typedef char* caddr_t;
   }
 #endif
 
+/*
+ * If the OS doesn't define AF_INET6 and struct in6_addr:
+ *
+ * define AF_INET6, so we can use it internally as a "this is an
+ * IPv6 address" indication;
+ *
+ * define struct in6_addr so that we can use it for IPv6 addresses.
+ */
+#ifndef HAVE_OS_IPV6_SUPPORT
+#define AF_INET6	24
+
+struct in6_addr {
+	union {
+		__uint8_t   __u6_addr8[16];
+		__uint16_t  __u6_addr16[8];
+		__uint32_t  __u6_addr32[4];
+	} __u6_addr;			/* 128-bit IP6 address */
+};
+#endif
+
+#ifndef NI_MAXHOST
+#define	NI_MAXHOST	1025
+#endif
+  
 #ifndef INET_ADDRSTRLEN
 #define INET_ADDRSTRLEN 16
 #endif