Dear all,
over the last week, i've worked on IPv6 support for NaviServer.
For this task, i took the following path:
1) build a version of NaviServer for IPv6
2) build a single code source for compiling either for IPv4 or IPv6
3) let the IPv6 version run the setup-files for IPv4 in the IPv6 version
4) Run regression test suite under IPv4 and/IPv6
5) Allow mixed mode (handle IPv4 and IPv6 by the same binary)
(requires some interface changes to handle generic sockaddrs)
Everything seems to work fine, one can work with the same
config files as before, and everything works as expected,
but one can as well listen on IPv6 addresses (e.g.
the IPv6 unspecified address "::"). IPv4->6 mapping is
activated, or the kernel allows to deliver as well
IPv4 traffic to the IPv6 interface, then one can talk
also multiple protocols. The mileage may vary depending on the
OS and kernel.
It is as well possible to deactivate IPv6 support at compile
time via --disable-ipv6.
Here is a summary of the necessary changes:
- Added a amall Abstraction API for IP-version agnostic calls:
Ns_LogSockaddr(), Ns_SockaddrGetPort(),
Ns_SockaddrGetSockLen(), Ns_SockaddrMask(), Ns_SockaddrMaskBits(),
Ns_SockaddrSetPort(), ns_inet_ntop(), ns_inet_pton()
- Replaced in interface more places where "sockaddr_in" (the IPv4
version of the sockaddr) with the generic (version agnostic)
sockaddr (also in IPv4 code to obtain API consistency when no IPv6
is available): Ns_BindSock(), Ns_ConnSetPeer(), Ns_GetSockAddr(),
Ns_SockBind(), Ns_SockBindUdp()
- The Ns_Sock structure contained sockaddr_in, which is not sufficient
to store IPv6 addresses. Therefore it was necessary to change
that to "sockaddr_storage" which guarantees to be large enough
to keep all kind of addresses. This affects as well driver modules
which communicate via the NaviServer managed sockets. Old drivers
might crash with the new structure. Therefore, I've bumped
NS_DRIVER_VERSION to 3 such that driver modules (also binaries)
can communicate that they support IPv6. In IPv6 mode, NaviServer
refuses to work with versions <3.
- Replaced all usages of ns_inet_ntoa() by ns_intet_ntop()
(except for legacy an minimal library support)
- Added log file warnings on various places, where NaviServer
was ignoring error states in socket communications silently.
- Transformed hash table for open listen ports to string keys
(the old code used 32bit IPv4-addresses as keys in hash tables)
- added test for ns_listencallback
- Ns_HttpParseHost: new abstraction for parsing host and port number.
Reason: IPv6 literal notation contains many colons, parsing
IP-literal notation according to RFC 3986 section 3.2.2 is necessary
(removed places where code was searching for ':' to expect the port)
- Added [ns_info ipv6] to obtain information whether the binary
supports IPv6 or not
- Added configure flag --disable-ipv6 to build NaviServer just with
IPv4 support.
- provide defines for core differences between IPv4 and IPv6
#ifdef HAVE_IPV6
# define NS_IP_LOOPBACK "::1"
# define NS_IP_UNSPECIFIED "::"
# define NS_SOCKADDR_IN sockaddr_storage
# define NS_IPADDR_SIZE INET6_ADDRSTRLEN
#else
# define NS_IP_LOOPBACK "127.0.0.1"
# define NS_IP_UNSPECIFIED "0.0.0.0"
# define NS_SOCKADDR_IN sockaddr_in
# define NS_IPADDR_SIZE INET_ADDRSTRLEN
#endif
- nsperm:
* Aligned implementation with the documentation
(hosts.allow/deny have comma-separated entries)
* Added submask specification in the form /xxx
(e.g. ::1/64)
* Use binary IPv4 and IPv6 values for hash and mask lookup
* Generalizing masking functions
* Refactor code to avoid memory leaks
* Updated documentation
- modules:
* nsudp and nsssl are now IPv6 aware/compliant
TODOs:
- more platform testing
(probably changes for Windows necessary, help is appreciated)
- remove commented out debug statements
- make more modules IPv6 compliant
- documentation updates
I've tested the generic and IPv4 only version via regression
test and random browsing on Mac OS X and Linux. If you
have other platforms, testing would be appreciated. There
are some adjustments for windows probably necessary
(in the absence of "configure", one has to add manually
"HAVE_IPV4" to the compile flags). Any help is welcome.
best regards
-gustaf neumann
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