diff --git a/ChangeLog b/ChangeLog
index a259f9ec5c..02853b2dc0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Fri Feb 15 20:29:11 2013  Tanaka Akira  <akr@fsij.org>
+
+	* ext/socket/sockport.h (SET_SIN_LEN): defined for strict-aliasing
+	  rule.
+	  (INIT_SOCKADDR_IN): ditto.
+
+	* ext/socket/raddrinfo.c (make_inetaddr): use INIT_SOCKADDR_IN.
+	  (addrinfo_ipv6_to_ipv4): ditto.
+
 Fri Feb 15 18:24:48 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/mkmf.rb (MakeMakefile#try_run): bail out explicitly if cross
diff --git a/ext/socket/raddrinfo.c b/ext/socket/raddrinfo.c
index e8955d7acb..067be4f831 100644
--- a/ext/socket/raddrinfo.c
+++ b/ext/socket/raddrinfo.c
@@ -253,7 +253,7 @@ make_inetaddr(unsigned int host, char *buf, size_t buflen)
 {
     struct sockaddr_in sin;
 
-    INIT_SOCKADDR((struct sockaddr *)&sin, AF_INET, sizeof(sin));
+    INIT_SOCKADDR_IN(&sin, AF_INET, sizeof(sin));
     sin.sin_addr.s_addr = host;
     make_ipaddr0((struct sockaddr*)&sin, sizeof(sin), buf, buflen);
 }
@@ -1929,7 +1929,7 @@ addrinfo_ipv6_to_ipv4(VALUE self)
     addr = &((struct sockaddr_in6 *)&rai->addr)->sin6_addr;
     if (IN6_IS_ADDR_V4MAPPED(addr) || IN6_IS_ADDR_V4COMPAT(addr)) {
         struct sockaddr_in sin4;
-        INIT_SOCKADDR((struct sockaddr *)&sin4, AF_INET, sizeof(sin4));
+        INIT_SOCKADDR_IN(&sin4, AF_INET, sizeof(sin4));
         memcpy(&sin4.sin_addr, (char*)addr + sizeof(*addr) - sizeof(sin4.sin_addr), sizeof(sin4.sin_addr));
         return rsock_addrinfo_new((struct sockaddr *)&sin4, (socklen_t)sizeof(sin4),
                                   PF_INET, rai->socktype, rai->protocol,
diff --git a/ext/socket/sockport.h b/ext/socket/sockport.h
index 517b8f7420..95f4214d44 100644
--- a/ext/socket/sockport.h
+++ b/ext/socket/sockport.h
@@ -22,6 +22,13 @@
 # define SET_SA_LEN(sa, len) (void)(len)
 #endif
 
+/* for strict-aliasing rule */
+#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
+# define SET_SIN_LEN(sa, len) (void)((sa)->sin_len = (len))
+#else
+# define SET_SIN_LEN(sa, len) SET_SA_LEN((struct sockaddr *)(sa), (len))
+#endif
+
 #define INIT_SOCKADDR(addr, family, len) \
   do { \
     struct sockaddr *init_sockaddr_ptr = (addr); \
@@ -31,6 +38,15 @@
     SET_SA_LEN(init_sockaddr_ptr, init_sockaddr_len); \
   } while (0)
 
+#define INIT_SOCKADDR_IN(addr, family, len) \
+  do { \
+    struct sockaddr_in *init_sockaddr_ptr = (addr); \
+    socklen_t init_sockaddr_len = (len); \
+    memset(init_sockaddr_ptr, 0, init_sockaddr_len); \
+    init_sockaddr_ptr->sin_family = (family); \
+    SET_SIN_LEN(init_sockaddr_ptr, init_sockaddr_len); \
+  } while (0)
+
 #ifndef IN_MULTICAST
 # define IN_CLASSD(i)	(((long)(i) & 0xf0000000) == 0xe0000000)
 # define IN_MULTICAST(i)	IN_CLASSD(i)