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Don't use link-local networks to determine the lowest cost of networks

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On Chrome Remote Desktop for iOS, if all of these are true:
* Enable the PORTALLOCATOR_DISABLE_COSTLY_NETWORKS flag.
* Connect an iPhone to a Mac.
* Turn off WiFi on the iPhone and keep mobile data on.
* Connect to a host on a different network from iPhone.

Then the connection can never succeed. The reason is that iOS uses a
special network interface with link-local IP to communicate with the Mac.
BasicPortAllocator sees that interface and thinks it costs less than the
cellular networks, then it removes all cellular networks. However, that
link-local network cannot connect to a peer on external network.

This CL changes the behavior of the PORTALLOCATOR_DISABLE_COSTLY_NETWORKS
so that it ignores the cost of link-local networks when determining the
lowest network cost.

Bug: webrtc:8780
Change-Id: I9bde50426b356fdbf89d4b826fc7b28c8c523c10
Reviewed-on: https://webrtc-review.googlesource.com/41460
Commit-Queue: Yuwei Huang <yuweih@google.com>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21738}
This commit is contained in:
Yuwei Huang
2018-01-22 17:01:28 -08:00
committed by Commit Bot
parent 5670c86aec
commit b181f71ee7
4 changed files with 74 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
p2p/client/basicportallocator.cc
View File

@ -644,6 +644,13 @@ std::vector<rtc::Network*> BasicPortAllocatorSession::GetNetworks() {
if (flags() & PORTALLOCATOR_DISABLE_COSTLY_NETWORKS) {
uint16_t lowest_cost = rtc::kNetworkCostMax;
for (rtc::Network* network : networks) {
// Don't determine the lowest cost from a link-local network.
// On iOS, a device connected to the computer will get a link-local
// network for communicating with the computer, however this network can't
// be used to connect to a peer outside the network.
if (rtc::IPIsLinkLocal(network->GetBestIP())) {
continue;
}
lowest_cost = std::min<uint16_t>(lowest_cost, network->GetCost());
}
networks.erase(std::remove_if(networks.begin(), networks.end(),

51
p2p/client/basicportallocator_unittest.cc
View File

@ -849,6 +849,57 @@ TEST_F(BasicPortAllocatorTest,
EXPECT_PRED4(HasCandidate, candidates_, "local", "udp", cellular);
}
// Test that if both PORTALLOCATOR_DISABLE_COSTLY_NETWORKS is set, and there is
// a WiFi network with link-local IP address and a cellular network, then the
// cellular candidate will still be gathered.
TEST_F(BasicPortAllocatorTest,
CellNotRemovedWhenCostlyNetworksDisabledAndWifiIsLinkLocal) {
SocketAddress wifi_link_local("169.254.0.1", 0);
SocketAddress cellular(IPAddress(0x12345601U), 0);
AddInterface(wifi_link_local, "test_wlan0", rtc::ADAPTER_TYPE_WIFI);
AddInterface(cellular, "test_cell0", rtc::ADAPTER_TYPE_CELLULAR);
allocator().set_flags(cricket::PORTALLOCATOR_DISABLE_STUN |
cricket::PORTALLOCATOR_DISABLE_RELAY |
cricket::PORTALLOCATOR_DISABLE_TCP |
cricket::PORTALLOCATOR_DISABLE_COSTLY_NETWORKS);
EXPECT_TRUE(CreateSession(cricket::ICE_CANDIDATE_COMPONENT_RTP));
session_->StartGettingPorts();
EXPECT_TRUE_SIMULATED_WAIT(candidate_allocation_done_,
kDefaultAllocationTimeout, fake_clock);
// Make sure we got both wifi and cell candidates.
EXPECT_EQ(2U, candidates_.size());
EXPECT_PRED4(HasCandidate, candidates_, "local", "udp", wifi_link_local);
EXPECT_PRED4(HasCandidate, candidates_, "local", "udp", cellular);
}
// Test that if both PORTALLOCATOR_DISABLE_COSTLY_NETWORKS is set, and there is
// a WiFi network with link-local IP address, a WiFi network with a normal IP
// address and a cellular network, then the cellular candidate will not be
// gathered.
TEST_F(BasicPortAllocatorTest,
CellRemovedWhenCostlyNetworksDisabledAndBothWifisPresent) {
SocketAddress wifi(IPAddress(0x12345600U), 0);
SocketAddress wifi_link_local("169.254.0.1", 0);
SocketAddress cellular(IPAddress(0x12345601U), 0);
AddInterface(wifi, "test_wlan0", rtc::ADAPTER_TYPE_WIFI);
AddInterface(wifi_link_local, "test_wlan1", rtc::ADAPTER_TYPE_WIFI);
AddInterface(cellular, "test_cell0", rtc::ADAPTER_TYPE_CELLULAR);
allocator().set_flags(cricket::PORTALLOCATOR_DISABLE_STUN |
cricket::PORTALLOCATOR_DISABLE_RELAY |
cricket::PORTALLOCATOR_DISABLE_TCP |
cricket::PORTALLOCATOR_DISABLE_COSTLY_NETWORKS);
EXPECT_TRUE(CreateSession(cricket::ICE_CANDIDATE_COMPONENT_RTP));
session_->StartGettingPorts();
EXPECT_TRUE_SIMULATED_WAIT(candidate_allocation_done_,
kDefaultAllocationTimeout, fake_clock);
// Make sure we got only wifi candidates.
EXPECT_EQ(2U, candidates_.size());
EXPECT_PRED4(HasCandidate, candidates_, "local", "udp", wifi);
EXPECT_PRED4(HasCandidate, candidates_, "local", "udp", wifi_link_local);
}
// Test that no more than allocator.max_ipv6_networks() IPv6 networks are used
// to gather candidates.
TEST_F(BasicPortAllocatorTest, MaxIpv6NetworksLimitEnforced) {

21
rtc_base/ipaddress.cc
View File

@ -303,6 +303,21 @@ bool IPIsLoopback(const IPAddress& ip) {
return false;
}
bool IPIsLinkLocal(const IPAddress& ip) {
switch (ip.family()) {
case AF_INET: {
uint32_t ip_in_host_order = ip.v4AddressAsHostOrderInteger();
return (ip_in_host_order >> 16) == ((169 << 8) | 254);
}
case AF_INET6: {
// Can't use the helper because the prefix is 10 bits.
in6_addr addr = ip.ipv6_address();
return addr.s6_addr[0] == 0xFE && addr.s6_addr[1] == 0x80;
}
}
return false;
}
bool IPIsPrivate(const IPAddress& ip) {
switch (ip.family()) {
case AF_INET: {
@ -440,12 +455,6 @@ bool IPIs6To4(const IPAddress& ip) {
return IPIsHelper(ip, k6To4Prefix, 16);
}
bool IPIsLinkLocal(const IPAddress& ip) {
// Can't use the helper because the prefix is 10 bits.
in6_addr addr = ip.ipv6_address();
return addr.s6_addr[0] == 0xFE && addr.s6_addr[1] == 0x80;
}
// According to http://www.ietf.org/rfc/rfc2373.txt, Appendix A, page 19. An
// address which contains MAC will have its 11th and 12th bytes as FF:FE as well
// as the U/L bit as 1.

2
rtc_base/ipaddress.h
View File

@ -154,6 +154,7 @@ bool IPFromString(const std::string& str, int flags,
InterfaceAddress* out);
bool IPIsAny(const IPAddress& ip);
bool IPIsLoopback(const IPAddress& ip);
bool IPIsLinkLocal(const IPAddress& ip);
bool IPIsPrivate(const IPAddress& ip);
bool IPIsUnspec(const IPAddress& ip);
size_t HashIP(const IPAddress& ip);
@ -161,7 +162,6 @@ size_t HashIP(const IPAddress& ip);
// These are only really applicable for IPv6 addresses.
bool IPIs6Bone(const IPAddress& ip);
bool IPIs6To4(const IPAddress& ip);
bool IPIsLinkLocal(const IPAddress& ip);
bool IPIsMacBased(const IPAddress& ip);
bool IPIsSiteLocal(const IPAddress& ip);
bool IPIsTeredo(const IPAddress& ip);