26 Nov
2009
26 Nov
'09
6:22 p.m.
On Nov 25, 2009 at 14:04, marius zbihlei <marius.zbihlei(a)1and1.ro> wrote:
Hello,
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
dns lookups.
"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). "
(http://linux.die.net/man/3/gethostbyname)
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:
http://people.redhat.com/drepper/userapi-ipv6.html
Any benefits from using these calls? Any problems from removing the old
calls?
I don't see any benefits in changing, only possible portability
problems.
Andrei