The virSocketParseAddr function was accepting any AF_* constant
and using that to set the ai_flags field in struct addrinfo.
This is invalid, since address families must go in the ai_family
field of the struct.

* src/util/network.c: Fix handling of address family
* src/conf/network_conf.c, src/network/bridge_driver.c: Pass
  AF_UNSPEC instead of relying on it being 0.

Some operations on socket addresses need to know the length of
the sockaddr struct for the particular address family. This
info was being discarded when passing around virSocketAddr
instances. Turn it from a union into a struct containing
union+socklen_t fields, so length is always kept around.

* src/util/network.h: Add socklen_t field to virSocketAddr
* src/util/network.c, src/network/bridge_driver.c,
  src/conf/domain_conf.c: Update to take account of new
  struct definition.

* src/util/network.c (getIPv6Addr): Manually join s6_addr bytes,
instead of assuming s6_addr16 shorts.
Reported by Justin Clifton; solution suggested by Bruno Haible.

That way it can be used to verify a numeric address without storing
the details
* src/util/network.c: change virSocketParseAddr to allow a null @addr
  parameter

git grep found 12 of the former but 100 of the latter in src/.

* src/remote/remote_driver.c (initialise_gnutls): Rename...
(initialize_gnutls): ...to this.
(doRemoteOpen): Adjust caller.
* src/xen/xen_driver.c (xenUnifiedOpen): Adjust output string.
* src/util/network.c: Adjust comments.
Suggested by Matthias Bolte.

This patch changes the network filtering code to use libvirt's existing
IPv4 and IPv6 address parsers/printers rather than my self-written ones.

I am introducing a new function in network.c that counts the number of
bits in a netmask and ensures that the given address is indeed a netmask,
return -1 on error or values of 0-32 for IPv4 addresses and 0-128 for
IPv6 addresses. I then based the function checking for valid netmask
on invoking this function.

Fix this warning, there is no need to use an intermediate,
different array pointer.
network.c: In function 'getIPv6Addr':
network.c:50: warning: dereferencing type-punned pointer will break strict-aliasing rules
* src/util/network.c: avoid an intermediary pointer cast

* src/util/network.c: getIPv4Addr() got broken when the input
  network address value got converted from network to host byte order

* src/util/network.c: Add htons and ntohs in virSocket(Get|Set)Port

__in6_u.__u6_addr16 is the private name for this struct member,
s6_addr16 is the public one
* src/util/network.c: dont use the private field, but the public one.

* src/util/network.[ch] Add functions for address->text and get/set
  port number
* src/libvirt_private.syms: add new entry points

* src/util/network.c: fix a few typo

* src/util/network.h src/util/network.c: utilities to parse network
  addresses, check netmask and compute ranges