commit fe67e668881b8b8d71b1570575c913cd287fafcf
author Renato Westphal <renatowestphal@gmail.com> Fri Mar 23 16:27:40 2012 -0300
committer David Lamparter <equinox@diac24.net> Fri Mar 23 20:51:28 2012 +0100
tree ce48b0028e879d4e6f938bb9dd583ed9f679fa96
parent aee567450eaf32877d00f47c4cc5d05c5fb85a51

lib: fix endianness bug in prefix.c

While defining two "maskbytes" arrays for the respective endiannesses,
the code was unconditionally using one that only worked on little endian
systems.

Use preprocessor macros to avoid the somewhat expensive
htonl/ntohl macros.

From: Renato Westphal <renatowestphal@gmail.com>
Signed-off-by: David Lamparter <equinox@diac24.net>

lib/prefix.c

diff --git a/lib/prefix.c b/lib/prefix.c
index 5e8cff0..fa2d2eb 100644
--- a/lib/prefix.c
+++ b/lib/prefix.c
@@ -31,7 +31,7 @@
 /* Maskbit. */
 static const u_char maskbit[] = {0x00, 0x80, 0xc0, 0xe0, 0xf0,
 			         0xf8, 0xfc, 0xfe, 0xff};
-static const u_int32_t maskbytes_host[] =
+static const u_int32_t maskbytes_big_endian[] =
 {
   0x00000000, /* /0  0.0.0.0         */
   0x80000000, /* /1  128.0.0.0       */
@@ -67,7 +67,8 @@
   0xfffffffe, /* /31 255.255.255.254 */
   0xffffffff  /* /32 255.255.255.255 */
 };
-static const u_int32_t maskbytes_network[] =
+
+static const u_int32_t maskbytes_little_endian[] =
 {
   0x00000000, /* /0  0.0.0.0         */
   0x00000080, /* /1  128.0.0.0       */
@@ -103,6 +104,7 @@
   0xfeffffff, /* /31 255.255.255.254 */
   0xffffffff  /* /32 255.255.255.255 */
 };
+
 static const struct in6_addr maskbytes6[] =
 {
   /* /0   */ { { { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } } },
@@ -2599,7 +2601,11 @@
 masklen2ip (const int masklen, struct in_addr *netmask)
 {
   assert (masklen >= 0 && masklen <= IPV4_MAX_BITLEN);
-  netmask->s_addr = maskbytes_network[masklen];
+#if (BYTE_ORDER == LITTLE_ENDIAN)
+  netmask->s_addr = maskbytes_little_endian[masklen];
+#elif (BYTE_ORDER == BIG_ENDIAN)
+  netmask->s_addr = maskbytes_big_endian[masklen];
+#endif
 }
 
 /* Convert IP address's netmask into integer. We assume netmask is
@@ -2621,7 +2627,11 @@
 apply_mask_ipv4 (struct prefix_ipv4 *p)
 {
   assert (p->prefixlen >= 0 && p->prefixlen <= IPV4_MAX_BITLEN);
-  p->prefix.s_addr &= maskbytes_network[p->prefixlen];
+#if (BYTE_ORDER == LITTLE_ENDIAN)
+  p->prefix.s_addr &= maskbytes_little_endian[p->prefixlen];
+#elif (BYTE_ORDER == BIG_ENDIAN)
+  p->prefix.s_addr &= maskbytes_big_endian[p->prefixlen];
+#endif
 }
 
 /* If prefix is 0.0.0.0/0 then return 1 else return 0. */