+/*
+ * Data types corresponding to multi-byte integral values within data
+ * structures. These are defined as arrays of octets, so that they're
+ * not aligned on their "natural" boundaries, and so that you *must*
+ * use the EXTRACT_ macros to extract them (which you should be doing
+ * *anyway*, so as not to assume a particular byte order or alignment
+ * in your code).
+ *
+ * We even want EXTRACT_U_1 used for 8-bit integral values, so we
+ * define nd_uint8_t and nd_int8_t as arrays as well.
+ */
+typedef unsigned char nd_uint8_t[1];
+typedef unsigned char nd_uint16_t[2];
+typedef unsigned char nd_uint24_t[3];
+typedef unsigned char nd_uint32_t[4];
+typedef unsigned char nd_uint40_t[5];
+typedef unsigned char nd_uint48_t[6];
+typedef unsigned char nd_uint56_t[7];
+typedef unsigned char nd_uint64_t[8];
+
+typedef signed char nd_int8_t[1];
+
+/*
+ * "unsigned char" so that sign extension isn't done on the
+ * individual bytes while they're being assembled.
+ */
+typedef unsigned char nd_int32_t[4];
+typedef unsigned char nd_int64_t[8];
+
+/*
+ * Use this for IPv4 addresses and netmasks.
+ *
+ * It's defined as an array of octets, so that it's not guaranteed to
+ * be aligned on its "natural" boundary (in some packet formats, it
+ * *isn't* so aligned). We have separate EXTRACT_ calls for them;
+ * sometimes you want the host-byte-order value, other times you want
+ * the network-byte-order value.
+ *
+ * Don't use EXTRACT_BE_U_4() on them, use EXTRACT_IPV4_TO_HOST_ORDER()
+ * if you want them in host byte order and EXTRACT_IPV4_TO_NETWORK_ORDER()
+ * if you want them in network byte order (which you want with system APIs
+ * that expect network-order IPv4 addresses, such as inet_ntop()).
+ *
+ * If, on your little-endian machine (e.g., an "IBM-compatible PC", no matter
+ * what the OS, or an Intel Mac, no matter what the OS), you get the wrong
+ * answer, and you've used EXTRACT_BE_U_4(), do *N*O*T* "fix" this by using
+ * EXTRACT_LE_U_4(), fix it by using EXTRACT_IPV4_TO_NETWORK_ORDER(),
+ * otherwise you're breaking the result on big-endian machines (e.g.,
+ * most PowerPC/Power ISA machines, System/390 and z/Architecture, SPARC,
+ * etc.).
+ *
+ * Yes, people do this; that's why Wireshark has tvb_get_ipv4(), to extract
+ * an IPv4 address from a packet data buffer; it was introduced in reaction
+ * to somebody who *had* done that.
+ */
+typedef unsigned char nd_ipv4[4];
+
+/*
+ * Use this for IPv6 addresses and netmasks.
+ */
+typedef unsigned char nd_ipv6[16];
+
+/*
+ * Use this for MAC addresses.
+ */
+#define MAC_ADDR_LEN 6 /* length of MAC addresses */
+typedef unsigned char nd_mac_addr[MAC_ADDR_LEN];
+
+/*
+ * Use this for blobs of bytes; make them arrays of nd_byte.
+ */
+typedef unsigned char nd_byte;
+
+/*
+ * Round up x to a multiple of y; y must be a power of 2.
+ */
+#ifndef roundup2
+#define roundup2(x, y) (((x)+((y)-1))&(~((y)-1)))
projects / tcpdump / blobdiff