From: Andreas Schwab <schwab@suse.de>
To: libc-alpha@sourceware.org
Subject: [PATCH] Update getaddrinfo to RFC 6724 (bug 29496)
Date: Tue, 06 Sep 2022 11:28:09 +0200 [thread overview]
Message-ID: <mvmedwo97iu.fsf@suse.de> (raw)
RFC 6724 is the successor of RFC 3484 and updated the default policy table
and the address selection rules. The policy table contains more entries
to depreference deprecated prefixes. The longest prefix match rule has
been updated to only compare the prefix part of the addresses, so that
addresses on the same subnet are no longer reordered.
---
posix/Makefile | 2 +-
posix/gai.conf | 48 ++++-----
posix/{tst-rfc3484-2.c => tst-rfc6724-2.c} | 6 +-
posix/{tst-rfc3484-3.c => tst-rfc6724-3.c} | 4 +-
posix/{tst-rfc3484.c => tst-rfc6724.c} | 6 +-
sysdeps/posix/getaddrinfo.c | 107 +++++++++++++--------
6 files changed, 98 insertions(+), 75 deletions(-)
rename posix/{tst-rfc3484-2.c => tst-rfc6724-2.c} (95%)
rename posix/{tst-rfc3484-3.c => tst-rfc6724-3.c} (96%)
rename posix/{tst-rfc3484.c => tst-rfc6724.c} (95%)
diff --git a/posix/Makefile b/posix/Makefile
index cb36b506c9..aacb515e62 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -123,7 +123,7 @@ tests += tst-spawn4-compat
endif
tests-internal := bug-regex5 bug-regex20 bug-regex33 \
- tst-rfc3484 tst-rfc3484-2 tst-rfc3484-3
+ tst-rfc6724 tst-rfc6724-2 tst-rfc6724-3
tests-container := bug-ga2 tst-vfork3
tests-time64 := tst-wait4-time64 tst-wait3-time64 tst-gnuglob64-time64
xtests := tst-getaddrinfo4 tst-getaddrinfo5 tst-sched_rr_get_interval
diff --git a/posix/gai.conf b/posix/gai.conf
index 4616ed005b..de76e2c26f 100644
--- a/posix/gai.conf
+++ b/posix/gai.conf
@@ -1,7 +1,7 @@
# Configuration for getaddrinfo(3).
#
# So far only configuration for the destination address sorting is needed.
-# RFC 3484 governs the sorting. But the RFC also says that system
+# RFC 6724 governs the sorting. But the RFC also says that system
# administrators should be able to overwrite the defaults. This can be
# achieved here.
#
@@ -16,40 +16,34 @@
# used. There are possible runtime problems. The default is no.
#
# label <mask> <value>
-# Add another rule to the RFC 3484 label table. See section 2.1 in
-# RFC 3484. The default is:
+# Add another rule to the RFC 6724 label table. See section 2.1 in
+# RFC 6724. The default is:
#
#label ::1/128 0
#label ::/0 1
#label 2002::/16 2
#label ::/96 3
#label ::ffff:0:0/96 4
-#label fec0::/10 5
-#label fc00::/7 6
-#label 2001:0::/32 7
-#
-# This default differs from the tables given in RFC 3484 by handling
-# (now obsolete) site-local IPv6 addresses and Unique Local Addresses.
-# The reason for this difference is that these addresses are never
-# NATed while IPv4 site-local addresses most probably are. Given
-# the precedence of IPv6 over IPv4 (see below) on machines having only
-# site-local IPv4 and IPv6 addresses a lookup for a global address would
-# see the IPv6 be preferred. The result is a long delay because the
-# site-local IPv6 addresses cannot be used while the IPv4 address is
-# (at least for the foreseeable future) NATed. We also treat Teredo
-# tunnels special.
+#label 2001::/32 5
+#label fec0::/10 11
+#label 3ffe::/16 12
+#label fc00::/7 13
#
# precedence <mask> <value>
-# Add another rule to the RFC 3484 precedence table. See section 2.1
-# and 10.3 in RFC 3484. The default is:
-#
-#precedence ::1/128 50
-#precedence ::/0 40
-#precedence 2002::/16 30
-#precedence ::/96 20
-#precedence ::ffff:0:0/96 10
-#
-# For sites which prefer IPv4 connections change the last line to
+# Add another rule to the RFC 6724 precedence table. See section 2.1
+# and 10.3 in RFC 6724. The default is:
+#
+#precedence ::1/128 50
+#precedence ::/0 40
+#precedence ::ffff:0:0/96 35
+#precedence 2002::/16 30
+#precedence 2001::/32 5
+#precedence fc00::/7 3
+#precedence ::/96 1
+#precedence fec0::/10 1
+#precedence 3ffe::/16 1
+#
+# For sites which prefer IPv4 connections change the coresponding line to
#
#precedence ::ffff:0:0/96 100
diff --git a/posix/tst-rfc3484-2.c b/posix/tst-rfc6724-2.c
similarity index 95%
rename from posix/tst-rfc3484-2.c
rename to posix/tst-rfc6724-2.c
index ce8ccd5f38..d882124513 100644
--- a/posix/tst-rfc3484-2.c
+++ b/posix/tst-rfc6724-2.c
@@ -62,7 +62,7 @@ _res_hconf_init (void)
nss_action_list __nss_hosts_database attribute_hidden;
/* This is the beginning of the real test code. The above defines
- (among other things) the function rfc3484_sort. */
+ (among other things) the function rfc6724_sort. */
#if __BYTE_ORDER == __BIG_ENDIAN
@@ -144,7 +144,7 @@ do_test (void)
struct sort_result_combo combo = { .results = results, .nresults = 2 };
- qsort_r (order, 2, sizeof (order[0]), rfc3484_sort, &combo);
+ qsort_r (order, 2, sizeof (order[0]), rfc6724_sort, &combo);
int result = 0;
if (results[order[0]].dest_addr->ai_family == AF_INET6)
@@ -174,7 +174,7 @@ do_test (void)
order[0] = 0;
- qsort_r (order, 2, sizeof (order[0]), rfc3484_sort, &combo);
+ qsort_r (order, 2, sizeof (order[0]), rfc6724_sort, &combo);
if (results[order[0]].dest_addr->ai_family == AF_INET6)
{
diff --git a/posix/tst-rfc3484-3.c b/posix/tst-rfc6724-3.c
similarity index 96%
rename from posix/tst-rfc3484-3.c
rename to posix/tst-rfc6724-3.c
index ecb163963f..59244fd73f 100644
--- a/posix/tst-rfc3484-3.c
+++ b/posix/tst-rfc6724-3.c
@@ -62,7 +62,7 @@ _res_hconf_init (void)
nss_action_list __nss_hosts_database attribute_hidden;
/* This is the beginning of the real test code. The above defines
- (among other things) the function rfc3484_sort. */
+ (among other things) the function rfc6724_sort. */
#if __BYTE_ORDER == __BIG_ENDIAN
@@ -141,7 +141,7 @@ do_test (void)
}
struct sort_result_combo combo = { .results = results, .nresults = naddrs };
- qsort_r (order, naddrs, sizeof (order[0]), rfc3484_sort, &combo);
+ qsort_r (order, naddrs, sizeof (order[0]), rfc6724_sort, &combo);
int result = 0;
for (int i = 0; i < naddrs; ++i)
diff --git a/posix/tst-rfc3484.c b/posix/tst-rfc6724.c
similarity index 95%
rename from posix/tst-rfc3484.c
rename to posix/tst-rfc6724.c
index 3b2052eb54..a1485ba59a 100644
--- a/posix/tst-rfc3484.c
+++ b/posix/tst-rfc6724.c
@@ -62,7 +62,7 @@ _res_hconf_init (void)
nss_action_list __nss_hosts_database attribute_hidden;
/* This is the beginning of the real test code. The above defines
- (among other things) the function rfc3484_sort. */
+ (among other things) the function rfc6724_sort. */
#if __BYTE_ORDER == __BIG_ENDIAN
@@ -91,7 +91,7 @@ static size_t order[naddrs];
static int expected[naddrs] =
{
- 9, 4, 3, 6, 5, 7, 8, 2, 0, 1
+ 2, 3, 4, 5, 6, 7, 8, 9, 0, 1
};
@@ -133,7 +133,7 @@ do_test (void)
}
struct sort_result_combo combo = { .results = results, .nresults = naddrs };
- qsort_r (order, naddrs, sizeof (order[0]), rfc3484_sort, &combo);
+ qsort_r (order, naddrs, sizeof (order[0]), rfc6724_sort, &combo);
int result = 0;
for (int i = 0; i < naddrs; ++i)
diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c
index bcff909b2f..3da296816a 100644
--- a/sysdeps/posix/getaddrinfo.c
+++ b/sysdeps/posix/getaddrinfo.c
@@ -1304,7 +1304,7 @@ static const struct prefixentry *labels;
/* Default labels. */
static const struct prefixentry default_labels[] =
{
- /* See RFC 3484 for the details. */
+ /* See RFC 6724 for the details. */
{ { .__in6_u
= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } }
@@ -1321,26 +1321,22 @@ static const struct prefixentry default_labels[] =
= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 } }
}, 96, 4 },
- /* The next two entries differ from RFC 3484. We need to treat
- IPv6 site-local addresses special because they are never NATed,
- unlike site-locale IPv4 addresses. If this would not happen, on
- machines which have only IPv4 and IPv6 site-local addresses, the
- sorting would prefer the IPv6 site-local addresses, causing
- unnecessary delays when trying to connect to a global IPv6 address
- through a site-local IPv6 address. */
+ { { .__in6_u
+ = { .__u6_addr8 = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+ }, 32, 5 },
{ { .__in6_u
= { .__u6_addr8 = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
- }, 10, 5 },
+ }, 10, 11 },
{ { .__in6_u
- = { .__u6_addr8 = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ = { .__u6_addr8 = { 0x3f, 0xfe, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
- }, 7, 6 },
- /* Additional rule for Teredo tunnels. */
+ }, 16, 12 },
{ { .__in6_u
- = { .__u6_addr8 = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ = { .__u6_addr8 = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
- }, 32, 7 },
+ }, 7, 13 },
{ { .__in6_u
= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
@@ -1354,23 +1350,39 @@ static const struct prefixentry *precedence;
/* The default precedences. */
static const struct prefixentry default_precedence[] =
{
- /* See RFC 3484 for the details. */
+ /* See RFC 6724 for the details. */
{ { .__in6_u
= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } }
}, 128, 50 },
+ { { .__in6_u
+ = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 } }
+ }, 96, 35 },
{ { .__in6_u
= { .__u6_addr8 = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
}, 16, 30 },
{ { .__in6_u
- = { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
- }, 96, 20 },
+ = { .__u6_addr8 = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+ }, 32, 5 },
+ { { .__in6_u
+ = { .__u6_addr8 = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+ }, 7, 3 },
{ { .__in6_u
= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 } }
- }, 96, 10 },
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+ }, 96, 1 },
+ { { .__in6_u
+ = { .__u6_addr8 = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+ }, 10, 1 },
+ { { .__in6_u
+ = { .__u6_addr8 = { 0x3f, 0xfe, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+ }, 16, 1 },
{ { .__in6_u
= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
@@ -1453,7 +1465,9 @@ fls (uint32_t a)
{
uint32_t mask;
int n;
- for (n = 0, mask = 1 << 31; n < 32; mask >>= 1, ++n)
+ if (a == 0)
+ return 0;
+ for (n = 0, mask = 1u << 31; n < 32; mask >>= 1, ++n)
if ((a & mask) != 0)
break;
return n;
@@ -1461,7 +1475,7 @@ fls (uint32_t a)
static int
-rfc3484_sort (const void *p1, const void *p2, void *arg)
+rfc6724_sort (const void *p1, const void *p2, void *arg)
{
const size_t idx1 = *(const size_t *) p1;
const size_t idx2 = *(const size_t *) p2;
@@ -1642,7 +1656,7 @@ rfc3484_sort (const void *p1, const void *p2, void *arg)
in_addr_t netmask1 = 0xffffffffu << (32 - a1->prefixlen);
if ((in1_src_addr & netmask1) == (in1_dst_addr & netmask1))
- bit1 = fls (in1_dst_addr ^ in1_src_addr);
+ bit1 = a1->prefixlen;
struct sockaddr_in *in2_dst
= (struct sockaddr_in *) a2->dest_addr->ai_addr;
@@ -1653,7 +1667,7 @@ rfc3484_sort (const void *p1, const void *p2, void *arg)
in_addr_t netmask2 = 0xffffffffu << (32 - a2->prefixlen);
if ((in2_src_addr & netmask2) == (in2_dst_addr & netmask2))
- bit2 = fls (in2_dst_addr ^ in2_src_addr);
+ bit2 = a2->prefixlen;
}
else if (a1->dest_addr->ai_family == PF_INET6)
{
@@ -1672,18 +1686,33 @@ rfc3484_sort (const void *p1, const void *p2, void *arg)
int i;
for (i = 0; i < 4; ++i)
- if (in1_dst->sin6_addr.s6_addr32[i]
- != in1_src->sin6_addr.s6_addr32[i]
- || (in2_dst->sin6_addr.s6_addr32[i]
- != in2_src->sin6_addr.s6_addr32[i]))
- break;
-
- if (i < 4)
{
- bit1 = fls (ntohl (in1_dst->sin6_addr.s6_addr32[i]
- ^ in1_src->sin6_addr.s6_addr32[i]));
- bit2 = fls (ntohl (in2_dst->sin6_addr.s6_addr32[i]
- ^ in2_src->sin6_addr.s6_addr32[i]));
+ uint32_t mask1, mask2;
+ if (i * 32 >= a1->prefixlen)
+ mask1 = 0;
+ else if ((i + 1) * 32 > a1->prefixlen)
+ mask1 = 0xffffffffu << (32 - (a1->prefixlen & 31));
+ else
+ mask1 = 0xffffffffu;
+ if (i * 32 >= a2->prefixlen)
+ mask2 = 0;
+ else if ((i + 1) * 32 > a2->prefixlen)
+ mask2 = 0xffffffffu << (32 - (a2->prefixlen & 31));
+ else
+ mask2 = 0xffffffffu;
+ if (((in1_dst->sin6_addr.s6_addr32[i]
+ ^ in1_src->sin6_addr.s6_addr32[i]) & htonl (mask1)) != 0
+ || ((in2_dst->sin6_addr.s6_addr32[i]
+ ^ in2_src->sin6_addr.s6_addr32[i]) & htonl (mask2)) != 0)
+ {
+ bit1 = fls (ntohl (in1_dst->sin6_addr.s6_addr32[i]
+ ^ in1_src->sin6_addr.s6_addr32[i])
+ & mask1);
+ bit2 = fls (ntohl (in2_dst->sin6_addr.s6_addr32[i]
+ ^ in2_src->sin6_addr.s6_addr32[i])
+ & mask2);
+ break;
+ }
}
}
@@ -1712,7 +1741,7 @@ in6aicmp (const void *p1, const void *p2)
}
-/* Name of the config file for RFC 3484 sorting (for now). */
+/* Name of the config file for RFC 6724 sorting (for now). */
#define GAICONF_FNAME "/etc/gai.conf"
@@ -2397,7 +2426,7 @@ getaddrinfo (const char *name, const char *service,
__libc_once_define (static, once);
__typeof (once) old_once = once;
__libc_once (once, gaiconf_init);
- /* Sort results according to RFC 3484. */
+ /* Sort results according to RFC 6724. */
struct sort_result *results;
size_t *order;
struct addrinfo *q;
@@ -2574,11 +2603,11 @@ getaddrinfo (const char *name, const char *service,
__libc_lock_lock (lock);
if (__libc_once_get (old_once) && gaiconf_reload_flag)
gaiconf_reload ();
- __qsort_r (order, nresults, sizeof (order[0]), rfc3484_sort, &src);
+ __qsort_r (order, nresults, sizeof (order[0]), rfc6724_sort, &src);
__libc_lock_unlock (lock);
}
else
- __qsort_r (order, nresults, sizeof (order[0]), rfc3484_sort, &src);
+ __qsort_r (order, nresults, sizeof (order[0]), rfc6724_sort, &src);
/* Queue the results up as they come out of sorting. */
q = p = results[order[0]].dest_addr;
--
2.37.3
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
next reply other threads:[~2022-09-06 9:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-06 9:28 Andreas Schwab [this message]
2023-09-04 15:53 ` Florian Weimer
2023-09-04 16:16 ` Andreas Schwab
2023-09-05 12:19 ` Florian Weimer
2023-09-05 12:31 ` Andreas Schwab
2023-09-05 12:44 ` Florian Weimer
2023-10-24 11:27 Andreas Schwab
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=mvmedwo97iu.fsf@suse.de \
--to=schwab@suse.de \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).