IPV6: address scope != scope id

There was a confusion between these: this commit tries to disambiguate them.
- Scope can be computed from the address itself.
- Scope id is scope dependent: it is currently defined as 1-based local
  interface index for link-local scoped addresses, and as a site index(?) for
  (obsolete) site-local addresses. Linux only supports it for link-local
  addresses.
The URL parser properly parses a scope id as an interface index, but stores it
in a field named "scope": confusion. The field has been renamed into "scope_id".
Curl_if2ip() used the scope id as it was a scope. This caused failures
to bind to an interface.
Scope is now computed from the addresses and Curl_if2ip() matches them.
If redundantly specified in the URL, scope id is check for mismatch with
the interface index.

This commit should fix SF bug #1451.

1 files changed, 11 insertions, 2 deletions

diff --git a/lib/if2ip.h b/lib/if2ip.h
index ac5875237..78bb0bd59 100644
--- a/lib/if2ip.h
+++ b/lib/if2ip.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -23,6 +23,14 @@
  ***************************************************************************/
 #include "curl_setup.h"
 
+/* IPv6 address scopes. */
+#define IPV6_SCOPE_GLOBAL       0       /* Global scope. */
+#define IPV6_SCOPE_LINKLOCAL    1       /* Link-local scope. */
+#define IPV6_SCOPE_SITELOCAL    2       /* Site-local scope (deprecated). */
+#define IPV6_SCOPE_NODELOCAL    3       /* Loopback. */
+
+unsigned int Curl_ipv6_scope(const struct sockaddr *sa);
+
 bool Curl_if_is_interface_name(const char *interf);
 
 typedef enum {
@@ -32,7 +40,8 @@ typedef enum {
 } if2ip_result_t;
 
 if2ip_result_t Curl_if2ip(int af, unsigned int remote_scope,
-                          const char *interf, char *buf, int buf_size);
+                          unsigned int remote_scope_id, const char *interf,
+                          char *buf, int buf_size);
 
 #ifdef __INTERIX