[ntp:questions] getaddrinfo2: "192.168.0.2" invalid host address.

Rick Jones rick.jones2 at hp.com
Mon Oct 15 21:18:51 UTC 2007


Aggie <c.kevin.lam at gmail.com> wrote:
> Sorry for posting the whole output messages.

> When I run ntpd with the debug option, I get the followings:
> //please take a quick look.

> If you do the search on "calling getaddrinfo(192.168.0.2,...)" from
> the following log, you will see

> getnetnum: calling getaddrinfo(192.168.0.2,...)
> reval before = 7476272
> retval = 9
> getaddrinfo2: "192.168.0.2" invalid host address.

> I'm very sure that 192.168.0.2 is the ip address of my host address.
> But then why is it saying it's invalid host address??

> It's weird getaddrinfo() is returning 9. Why??

Can you also take a tcpdump trace to see if the getaddrinfo() call
results in DNS traffic?  The getaddrinfo() call, while normally meant
to map a hostname (what I think you called a host address) to an IP
address, can be passed an IP adddress - as a string - and it will use
that.  However, if it decided to pass that particular sort of IP
address to a DNS server, some DNS servers will not be pleased with an
RFC1918 "private" IP such as a 192.168 and may return an error
message.  One would think that a well-written getaddrinfo() would
notice correctly when something was an IP rather than a name but then
with my experience with netperf, there are still steps on the learning
curve for getaddrinfo implementations...

Now, if that code in NTP is really trying to map from an IP address to
a host name, then it should be calling getnameinfo() rather than
getaddrinfo().

EBADF (errno 9) is indeed a bit strange to be getting - makes me
wonder if the socket() call made by getaddrinfo() was unsuccessful.  A
system call trace of the behaviour migth be a good thing to take - you
would then see the system calls being made and which failed within the
getaddrinfo() call.  However, looking at the manpage (HP-UX 11.11) for
getaddrinfo() tells me that the return value isn't an errno but a
getaddrinfo-specific error code.  In that context a value of "9" might
not be so weird.   On my system it seems those values (EAI_mumble) are in /usr/include/netdb.h:

$ find /usr/include -exec grep -l EAI_FAIL {} \;
/usr/include/netdb.h

and when I look there it suggests that a value of 9 means:

#  define EAI_SERVICE      9      /* service not supported for ai_socktype */

which implies (in my mind) that one of the struct addrinfo fields were
off a bit as to as_socktype or ai_protocol.

rick jones
-- 
portable adj, code that compiles under more than one compiler
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...




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