[sr-dev] gethostbyname() usage in resolving hostname
andrei at iptel.org
Thu Nov 26 18:22:28 CET 2009
On Nov 25, 2009 at 14:04, marius zbihlei <marius.zbihlei at 1and1.ro> wrote:
> I have seen that sip-router (and also kamailio) uses the old
> gethostbyname()/gethostbyname2() (for IPv6) method of resolving hostnames.
In general sr uses its own dns cache. gethostbyname() is used only if
compiled without dns cache support and from some modules.
> These calls have been deprecated according to the POSIX 2001 standard
> these calls are obsolete: Quote from the gethostbyname manpage
They might be deprecated, but they are still the most portable way of doing
> "POSIX.1-2001 marks *gethostbyaddr*() and *gethostbyname*() obsolescent.
> See *getaddrinfo <http://linux.die.net/man/3/getaddrinfo>*(3),
> *getnameinfo <http://linux.die.net/man/3/getnameinfo>*(3), *gai_strerror
> <http://linux.die.net/man/3/gai_strerror>*(3). "
> How about changing these calls to the new and improved API(getaddrinfo)?
> Some benefits of using the getaddrinfo API:
> 1. Thread safe calls (also async-sig-safe)
We don't care about that (we don't have threads and we don't use them
from signal handlers).
> 2. IPv4/IPv6 compliant
same goes for gethostbyname2 or getipnodebyname (solaris).
> 3. Order or returned addresses conforming to RFC 3484 (private network
> address returned first) (http://udrepper.livejournal.com/16116.html)
> For a more complete description of the differences , I point to Urlich
> Drepper's excelent article:
> Any benefits from using these calls? Any problems from removing the old
I don't see any benefits in changing, only possible portability
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