From: "akira yamada / やまだあきら" <akira@...>
Date: 2000-05-10T12:32:35+09:00
Subject: [ruby-dev:9648] Re: host.conf は参照しないの？


Wed, 10 May 2000 02:06:22 +0900 頃の
   Mail-Count: 9646
      Subject: [ruby-dev:9646] Re: host.conf は参照しないの？   
についてのお話にて Yukihiro Matsumoto さん曰く… 
(Y == matz@netlab.co.jp (Yukihiro Matsumoto) さん)

In article 9646, <E12pDMG-00018A-00@ev.netlab.co.jp>
Y>                                       [ruby-dev:9644]の配列
Y> を使う方法はちょっと脆弱な気がします。コンパイル時に指定でき
Y> ればそれで良いというようなものなのでしょうか。それともやっぱ
Y> り動的に指定できないと駄目？

extconf に with_config("ipv6-lookup-order","INET") を追加した上で, 
たとえばこんなんだとどうですかね? 

diff -rU3 /home/akira/src/ruby-cvs/ruby_1_4/ext/socket/socket.c ./socket.c
--- /src/ruby-cvs/ruby_1_4/ext/socket/socket.c	Mon May  8 06:55:27 2000
+++ ./socket.c	Wed May 10 12:27:10 2000
@@ -104,6 +104,78 @@
 };
 #endif
 
+#ifdef INET6
+#define LOOKUP_ORDERS		3
+int lookup_order_table[LOOKUP_ORDERS][LOOKUP_ORDERS] = {
+#define LOOKUP_ORDER_INET	0
+  {PF_UNSPEC, PF_UNSPEC, PF_UNSPEC},	/* 0:unspec */
+#define LOOKUP_ORDER_INET6	1
+  {PF_INET, PF_INET6, PF_UNSPEC},	/* 1:inet inet6 */
+#define LOOKUP_ORDER_UNSPEC	2
+  {PF_INET6, PF_INET, PF_UNSPEC}	/* 2:inet6 inet */
+};
+#if   DEFAULT_LOOKUP_ORDER == INET
+# define LOOKUP_ORDER_DEFAULT LOOKUP_ORDER_INET
+#elif DEFAULT_LOOKUP_ORDER == INET6
+# define LOOKUP_ORDER_DEFAULT LOOKUP_ORDER_INET6
+#elif DEFAULT_LOOKUP_ORDER == UNSPEC
+# define LOOKUP_ORDER_DEFAULT LOOKUP_ORDER_UNSPEC
+#endif
+static int
+rb_getaddrinfo(nodename, servname, hints, res)
+     char *nodename;
+     char *servname;
+     struct addrinfo *hints;
+     struct addrinfo **res;
+{
+
+  struct addrinfo tmp_hints;
+  int i, af, error;
+  VALUE lookup_order;
+  ID lookup_order_id;
+
+  lookup_order_id = rb_intern("LOOKUP_ORDER");
+#if 0
+  if (rb_const_defined(rb_cSocket, lookup_order_id)) {
+    lookup_order = rb_const_get(rb_cSocket, lookup_order_id);
+  } 
+#endif
+  if (rb_const_defined(rb_cObject, lookup_order_id)) {
+    lookup_order = rb_const_get(rb_cObject, lookup_order_id);
+  }
+  else {
+    lookup_order = LOOKUP_ORDER_DEFAULT;
+  }
+
+  if (TYPE(lookup_order) != T_FIXNUM) {
+    rb_raise(rb_eRuntimeError, 
+	     "invalid value of type for LOOKUP_ORDER (expected Fixnum)");
+  }
+  lookup_order = FIX2INT(lookup_order);
+
+  if (lookup_order < 0 || LOOKUP_ORDERS <= lookup_order) {
+    rb_raise(rb_eRuntimeError, "invalid value for LOOKUP_ORDER");
+  }
+
+  for (i = 0; i < LOOKUP_ORDERS; i++) {
+    af = lookup_order_table[lookup_order][i];
+    MEMCPY(&tmp_hints, hints, struct addrinfo, 1);
+    tmp_hints.ai_family = af;
+    error = getaddrinfo(nodename, servname, &tmp_hints, res);
+    if (error) {
+      if (tmp_hints.ai_family == PF_UNSPEC) {
+	break;
+      }
+    }
+    else {
+      break;
+    }
+  }
+
+  return error;
+}
+#endif
+
 #ifdef NT
 static void
 sock_finalize(fptr)
@@ -545,7 +617,11 @@
     MEMZERO(&hints, struct addrinfo, 1);
     hints.ai_family = PF_UNSPEC;
     hints.ai_socktype = SOCK_DGRAM;
+#ifndef INET6
     error = getaddrinfo(hostp, portp, &hints, &res);
+#else
+    error = rb_getaddrinfo(hostp, portp, &hints, &res);
+#endif
     if (error) {
 	if (hostp && hostp[strlen(hostp)-1] == '\n') {
 	    rb_raise(rb_eSocket, "newline at the end of hostname");
@@ -736,7 +812,11 @@
     if (type == INET_SERVER) {
 	hints.ai_flags = AI_PASSIVE;
     }
+#ifndef INET6
     error = getaddrinfo(host, portp, &hints, &res0);
+#else
+    error = rb_getaddrinfo(host, portp, &hints, &res0);
+#endif
     if (error) {
 	rb_raise(rb_eSocket, "%s", gai_strerror(error));
     }
@@ -1755,9 +1835,11 @@
     if (!NIL_P(family)) {
 	hints.ai_family = NUM2INT(family);
     }
+#ifndef INET6
     else {
 	hints.ai_family = PF_UNSPEC;
     }
+#endif
     if (!NIL_P(socktype)) {
 	hints.ai_socktype = NUM2INT(socktype);
     }
@@ -1767,7 +1849,16 @@
     if (!NIL_P(flags)) {
 	hints.ai_flags = NUM2INT(flags);
     }
+#ifndef INET6
     error = getaddrinfo(hptr, pptr, &hints, &res);
+#else
+    if (!NIL_P(family)) {
+      error = getaddrinfo(hptr, pptr, &hints, &res);
+    }
+    else {
+      error = rb_getaddrinfo(hptr, pptr, &hints, &res);
+    }
+#endif
     if (error) {
 	rb_raise(rb_eSocket, "%s", gai_strerror(error));
     }
@@ -2035,6 +2126,11 @@
 #endif
 #ifdef PF_INET6
     sock_define_const("PF_INET6", PF_INET6);
+#endif
+#ifdef INET6
+    sock_define_const("LOOKUP_INET", LOOKUP_ORDER_INET);
+    sock_define_const("LOOKUP_INET6", LOOKUP_ORDER_INET6);
+    sock_define_const("LOOKUP_UNSPEC", LOOKUP_ORDER_UNSPEC);
 #endif
 
     sock_define_const("MSG_OOB", MSG_OOB);

ただ, これをするなら, ホントは, 
Socket::LOOKUP_ORDER とかでなんとかしたいとこなんでしょうが, 
うまい方法がわかんなかったです. 

# バランス悪いような…