Package: iproute Version: 20100519-3 Severity: normal Tags: patch # Summary
The "ip monitor" command does properly decode the "preferred" and
"valid" lifetime records in router advertisements from netlink
messages.
# How to repeat
On a host in a network with a running radvd, do
ip monitor | grep preferr
Optionally in a second shell to speed up things
rdisc6 eth0
## Expected behaviour
Blocks of two lines repeating every few minutes:
valid_lft 86400sec preferred_lft 14400sec
prefix $PREFIX::/64 dev eth0 onlink autoconf valid 86400 preferred 14400
where the first line is the continuation line of an auto-configuration,
and `$PREFIX` is the prefix configured in radvd. The "valid" and
"preferred" numbers match.
## Observed behaviour
First line as above, but then
prefix $PREFIX::/64 dev eth0 onlink autoconf valid 14400 preferred 131084
## Explanation
The netlink packet in question is
0c 00 02 00 # len 12 octets, type PREFIX_CACHEINFO (2)
40 38 00 00 # preferred: 14400 = 0x00003840
80 51 01 00 # valid: 86400 = 0x00015180
iproute however does an of-by-one double word and picks
* 131084 = 0x0002000c as preferred
* 14400 = 0x00003840 as valid
# How to fix
diff --git a/ip/ipprefix.c b/ip/ipprefix.c
index cb1f582..d8327be 100644
--- a/ip/ipprefix.c
+++ b/ip/ipprefix.c
@@ -92,7 +92,7 @@ int print_prefix(const struct sockaddr_nl *who, struct
nlmsghdr *n, void *arg)
if (tb[PREFIX_CACHEINFO]) {
struct prefix_cacheinfo *pc;
- pc = (struct prefix_cacheinfo *)tb[PREFIX_CACHEINFO];
+ pc = (struct prefix_cacheinfo *)RTA_DATA(tb[PREFIX_CACHEINFO]);
fprintf(fp, "valid %u ", pc->valid_time);
fprintf(fp, "preferred %u ", pc->preferred_time);
Appearently this bug still exists in Debian sid (20110629-1).
Cheers,
Christoph
-- System Information:
Debian Release: 6.0.2
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: i386 (i686)
Kernel: Linux 2.6.39.3 (PREEMPT)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Versions of packages iproute depends on:
ii libc6 2.11.2-10 Embedded GNU C Library: Shared lib
ii libdb4.8 4.8.30-2 Berkeley v4.8 Database Libraries [
Versions of packages iproute recommends:
ii libatm1 1:2.5.1-1.2 shared library for ATM (Asynchrono
Versions of packages iproute suggests:
pn iproute-doc <none> (no description available)
-- no debconf information
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