Add IPv6 probe support for Windows...

Add IPv6 probe support for Windows

This is meant to test to see if AI_ADDRCONFIG is doing its
job in windows, or if we have to do the scans when there is
a network change.

Also switch to always doing probe support on Mac/Linux platforms.
There appears to be (on aggregate) around a 40% degradation of
DNS resolution times on the Mac, and about 17% degration on
Linux, when we don't probe.  It is likely that a few users
are greatly impacted by this, and are able to move the average
of the whole user population.


BUG=12754
BUG=25680
r=wtc

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=42544

[jar (doing other things), 2010-03-23 23:40:48]

Wtc,

Please review, and I'll try to get it into the next dev build.

Thanks,

Jim

[wtc, 2010-03-24 19:31:46]

LGTM, with one bug (about calling WSAGetLastError) and some
nits.

http://codereview.chromium.org/1210003/diff/14001/15001
File net/base/net_util.cc (right):

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1638
net/base/net_util.cc:1638: test_socket = WSASocket(AF_INET, SOCK_DGRAM, 0, 0, 0,
0);
Nit: use NULL as the fourth argument because it's a pointer
(LPWSAPROTOCOL_INFO lpProtocolInfo).

Can you try socket(AF_INET, SOCK_STREAM, 0)?

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1640
net/base/net_util.cc:1640: INTERFACE_INFO interfaces[2048];
This is an array of INTERFACE_INFOs, rather than chars.
So 2048 is too big.  I think 128 should be big enough.

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1641
net/base/net_util.cc:1641: unsigned long bytes_written = 0;
Define this variable as DWORD.

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1642
net/base/net_util.cc:1642: int rv = WSAIoctl(test_socket,
SIO_GET_INTERFACE_LIST, 0, 0, interfaces,
Nit: some of the 0's should be changed to NULL's if they're
pointers.

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1647
net/base/net_util.cc:1647: if (rv == WSAEFAULT)
rv is either 0 or SOCKET_ERROR.  You need to call
WSAGetLastError() to get the error code and compare that
with WSAEFAULT.

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1663
net/base/net_util.cc:1663: // Safe cast (via union) since this is AF_INET6.
Nit: remove this comment.  There is no cast.

[jar (doing other things), 2010-03-24 20:46:31]

Changes made per wtc

http://codereview.chromium.org/1210003/diff/14001/15001
File net/base/net_util.cc (right):

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1638
net/base/net_util.cc:1638: test_socket = WSASocket(AF_INET, SOCK_DGRAM, 0, 0, 0,
0);
On 2010/03/24 19:31:47, wtc wrote:
> Nit: use NULL as the fourth argument because it's a pointer
> (LPWSAPROTOCOL_INFO lpProtocolInfo).
> 
> Can you try socket(AF_INET, SOCK_STREAM, 0)?

Done.

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1640
net/base/net_util.cc:1640: INTERFACE_INFO interfaces[2048];
On 2010/03/24 19:31:47, wtc wrote:
> This is an array of INTERFACE_INFOs, rather than chars.
> So 2048 is too big.  I think 128 should be big enough.

The size was intentional to be ridiculously safe (and not have to repeatedly
call the function.  I'll lower it, and we'll hopefully never get the error.

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1641
net/base/net_util.cc:1641: unsigned long bytes_written = 0;
On 2010/03/24 19:31:47, wtc wrote:
> Define this variable as DWORD.

Done.

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1642
net/base/net_util.cc:1642: int rv = WSAIoctl(test_socket,
SIO_GET_INTERFACE_LIST, 0, 0, interfaces,
On 2010/03/24 19:31:47, wtc wrote:
> Nit: some of the 0's should be changed to NULL's if they're
> pointers.

Done.

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1647
net/base/net_util.cc:1647: if (rv == WSAEFAULT)
On 2010/03/24 19:31:47, wtc wrote:
> rv is either 0 or SOCKET_ERROR.  You need to call
> WSAGetLastError() to get the error code and compare that
> with WSAEFAULT.

Done.

http://codereview.chromium.org/1210003/diff/14001/15001#newcode1663
net/base/net_util.cc:1663: // Safe cast (via union) since this is AF_INET6.
On 2010/03/24 19:31:47, wtc wrote:
> Nit: remove this comment.  There is no cast.

Done.

[wtc, 2010-03-24 21:42:57]

LGTM.