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Change 1.1.1.1 pseudo-IP used for default route hack to 25.255.255.254, since 1.1.1.1 is from a now-in-use IPv4 block while 25.0.0.0/8 is still unrouted. It can be changed in the future without impacting anything, since Windows keys off the MAC not the IP to classify networks.

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This commit is contained in:
Adam Ierymenko 2014-08-21 08:26:39 -07:00
parent 9d5819ff44
commit 44d58ee871
1 changed files with 10 additions and 11 deletions
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21
osnet/WindowsEthernetTap.cpp
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@ -646,21 +646,20 @@ void WindowsEthernetTap::threadMain()
*
* Yes, you read that right.
*
* But these networks don't usually have default routes, so what
* do we do? Answer: add a fake one that's never used and goes
* nowhere. But it's got to resolve to an ARP address. So why
* don't we just make up one of those too?!? Shove it in there
* as a permanent statuc ARP entry and now Windows will think it
* has a real live default route at our bogus IP.
* The default route workaround is also known, but for this to
* work there must be a known default IP that resolves to a known
* ARP address. This works for an OpenVPN tunnel, but not here
* because this isn't a tunnel. It's a mesh. There is no "other
* end," or any other known always on IP.
*
* So let's make a fake one and shove it in there along with its
* fake static ARP entry. Also makes it instant-on and static.
*
* We'll have to see what DHCP does with this. In the future we
* probably will not want to do this on DHCP-enabled networks, so
* when we enable DHCP we will go in and yank this wacko hacko from
* the routing table before doing so.
*
* But yes, this works, and it makes our networks look and behave
* the way they should.
*
* Like Jesse Pinkman would say: "YEEEEAAH BITCH!" */
for(int i=0;i<8;++i) { // also wait up to 8s for this, though if we got the NLM part we're probably okay
MIB_IPFORWARD_ROW2 nr;
@ -669,7 +668,7 @@ void WindowsEthernetTap::threadMain()
nr.InterfaceLuid.Value = _deviceLuid.Value;
nr.DestinationPrefix.Prefix.si_family = AF_INET; // rest is left as 0.0.0.0/0
nr.NextHop.si_family = AF_INET;
nr.NextHop.Ipv4.sin_addr.s_addr = 0x01010101; // 1.1.1.1
nr.NextHop.Ipv4.sin_addr.s_addr = htonl(0x19fffffe); // 25.255.255.254 -- unrouted IPv4 block
nr.Metric = 9999; // do not use as real default route
nr.Protocol = MIB_IPPROTO_NETMGMT;
DWORD result = CreateIpForwardEntry2(&nr);
@ -677,7 +676,7 @@ void WindowsEthernetTap::threadMain()
MIB_IPNET_ROW2 ipnr;
memset(&ipnr,0,sizeof(ipnr));
ipnr.Address.si_family = AF_INET;
ipnr.Address.Ipv4.sin_addr.s_addr = 0x01010101;
ipnr.Address.Ipv4.sin_addr.s_addr = nr.NextHop.Ipv4.sin_addr.s_addr;
ipnr.InterfaceLuid.Value = _deviceLuid.Value;
ipnr.PhysicalAddress[0] = _mac[0] ^ 0x10; // just make something up that's consistent and not part of this net
ipnr.PhysicalAddress[1] = 0x00;