From 5bc4ae9d5746e65909a0bdab60e7bd598d4401c7 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Mon, 23 Dec 2019 08:53:57 -0800 Subject: Clear any host-specific NDP state when becoming a router This change supports clearing all host-only NDP state when NICs become routers. All discovered routers, discovered on-link prefixes and auto-generated addresses will be invalidated when becoming a router. This is because normally, routers do not process Router Advertisements to discover routers or on-link prefixes, and do not do SLAAC. Tests: Unittest to make sure that all discovered routers, discovered prefixes and auto-generated addresses get invalidated when transitioning from a host to a router. PiperOrigin-RevId: 286902309 --- pkg/tcpip/stack/stack.go | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) (limited to 'pkg/tcpip/stack/stack.go') diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go index 0e88643a4..7a9600679 100644 --- a/pkg/tcpip/stack/stack.go +++ b/pkg/tcpip/stack/stack.go @@ -662,11 +662,31 @@ func (s *Stack) Stats() tcpip.Stats { } // SetForwarding enables or disables the packet forwarding between NICs. +// +// When forwarding becomes enabled, any host-only state on all NICs will be +// cleaned up. func (s *Stack) SetForwarding(enable bool) { // TODO(igudger, bgeffon): Expose via /proc/sys/net/ipv4/ip_forward. s.mu.Lock() + defer s.mu.Unlock() + + // If forwarding status didn't change, do nothing further. + if s.forwarding == enable { + return + } + s.forwarding = enable - s.mu.Unlock() + + // If this stack does not support IPv6, do nothing further. + if _, ok := s.networkProtocols[header.IPv6ProtocolNumber]; !ok { + return + } + + if enable { + for _, nic := range s.nics { + nic.becomeIPv6Router() + } + } } // Forwarding returns if the packet forwarding between NICs is enabled. -- cgit v1.2.3