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forked from pool/glibc
Petr Baudis 2010-04-20 11:16:55 +00:00 committed by Git OBS Bridge
parent 67f6df3eb9
commit de4358c978
3 changed files with 81 additions and 0 deletions

74
glibc-gai-private4.diff Normal file
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@ -0,0 +1,74 @@
Pending acceptance upstream when this gets RFC'd:
http://sourceware.org/bugzilla/show_bug.cgi?id=11438
--- posix/gai.conf~ 2010-04-20 13:05:50.197813000 +0200
+++ posix/gai.conf 2010-04-20 13:08:46.472675000 +0200
@@ -66,3 +66,68 @@
#scopev4 ::ffff:172.16.0.0/108 5
#scopev4 ::ffff:192.168.0.0/112 5
#scopev4 ::ffff:0.0.0.0/96 14
+
+
+# Back in 2003, the sorting algorithm used by getaddrinfo() was defined in RFC
+# 3484. However, this document did not take into account (or foresee) the
+# ubiquity of IPv4 NAT on today's internet. This in turn causes some real
+# operational problems that's hindering the deployment of IPv6 for content
+# providers.
+#
+# The problem scenario is the following:
+#
+# An end user is located in a network numbered with private (RFC 1918) IPv4
+# addresses and transitional 6to4 (RFC 3056) IPv6 addresses. The network is
+# connected to the internet by a CPE/SOHO device implementing NAT for IPv4 and
+# anycasted 6to4 (RFC 3068) for IPv6.
+#
+# When the user attempts to connect to a server whose hostname has both IPv4
+# and IPv6 addresses published in DNS, an IPv6 connection using the
+# transitional 6to4 service will be preferred. This happens because the scope
+# comparsion fails for IPv4, the RFC 1918 addresses are assumed to have
+# site-local scope, which is smaller than the global scope of the server's IPv4
+# address. For IPv6, both the server's and the client's (6to4) address have
+# global scope.
+#
+# Unfortunately, the operational reality is that a transitional technique such
+# as 6to4 is much less reliable than IPv4. The relay routers might be located
+# far away from the optimal IPv4 path, and thus cause a significant latency
+# increase, or they might not even work optimally (they're usually operated by
+# voulenteering third parties on a best-effort basis), and finally some ISPs
+# simply filter away all proto-41 traffic. Transitional techniques are useful
+# to give end users with IPv4-only service a real shot at accessing IPv6-only
+# content, but it should never be preferred over IPv4 service when accessing
+# dual-stacked content.
+#
+# RFC 3484 even acknowledges this, by saying to "«avoid the use of transitional
+# addresses when native addresses are available"».
+#
+# An IETF draft document which describes the problem in a much more detailed
+# manner than I have is available here:
+#
+# http://tools.ietf.org/html/draft-denis-v6ops-nat-addrsel-00
+#
+# There's also an IETF draft that aims to revise RFC 3484 in order to fix this
+# problem (amongst others):
+#
+# http://tools.ietf.org/html/draft-arifumi-6man-rfc3484-revise-02
+#
+# Quoting from this document:
+#
+# > 2.7. To change private IPv4 address scope
+# >
+# > As detailed in Remi's draft [I-D.denis-v6ops-nat-addrsel], when a
+# > host is in NATed site, and has a private IPv4 address and
+# > transitional addresses like 6to4 and Teredo, the host chooses
+# > transitional IPv6 address to access most of the dual-stack servers.
+# >
+# > This is because private IPv4 address is defined to be site-local
+# > scope, and as in RFC 3484, the scope matching rules (Rule 2) set
+# > lower priority for private IPv4 address.
+# >
+# > By changing the address scope of private IPv4 address to global, this
+# > problem can be solved.
+
+scopev4 ::ffff:10.0.0.0/104 14
+scopev4 ::ffff:172.16.0.0/108 14
+scopev4 ::ffff:192.168.0.0/112 14

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@ -1,3 +1,8 @@
-------------------------------------------------------------------
Tue Apr 20 13:15:19 CEST 2010 - pbaudis@suse.cz
- Consider private IPv4 addresses as global-scope in gai.conf [bnc#597616]
-------------------------------------------------------------------
Wed Mar 24 13:04:12 CET 2010 - pbaudis@suse.cz

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@ -133,6 +133,7 @@ Patch60: ld-prelink-unique.diff
Patch61: glibc-ppc64-vdso-time.diff
Patch62: nptl-ppc64-vdso-timedwait.diff
Patch63: glibc-getnprocs.diff
Patch64: glibc-gai-private4.diff
Patch500: ARM_glibc-2.10.1-local-eabi-wchar.diff
Patch501: ARM_glibc-2.10.1-local-hwcap-updates.diff
Patch502: ARM_glibc-2.10.1-local-lowlevellock.diff
@ -357,6 +358,7 @@ rm nscd/s-stamp
%patch61 -p1
%patch62 -p1
%patch63 -p1
%patch64
%ifarch %arm armv5tel armv7l
%patch500
%patch501