Handle subnet and broadcast addresses correctly with NIC.subnets

This also renames "subnet" to "addressRange" to avoid any more confusion with
an interface IP's subnet.

Lastly, this also removes the Stack.ContainsSubnet(..) API since it isn't used
by anyone. Plus the same information can be obtained from
Stack.NICAddressRanges().

PiperOrigin-RevId: 267229843

1 files changed, 11 insertions, 21 deletions

diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 1d5e84a8b..6beca6ae8 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -702,14 +702,14 @@ func (s *Stack) CheckNIC(id tcpip.NICID) bool {
 }
 
 // NICSubnets returns a map of NICIDs to their associated subnets.
-func (s *Stack) NICSubnets() map[tcpip.NICID][]tcpip.Subnet {
+func (s *Stack) NICAddressRanges() map[tcpip.NICID][]tcpip.Subnet {
 	s.mu.RLock()
 	defer s.mu.RUnlock()
 
 	nics := map[tcpip.NICID][]tcpip.Subnet{}
 
 	for id, nic := range s.nics {
-		nics[id] = append(nics[id], nic.Subnets()...)
+		nics[id] = append(nics[id], nic.AddressRanges()...)
 	}
 	return nics
 }
@@ -810,45 +810,35 @@ func (s *Stack) AddProtocolAddressWithOptions(id tcpip.NICID, protocolAddress tc
 	return nic.AddAddress(protocolAddress, peb)
 }
 
-// AddSubnet adds a subnet range to the specified NIC.
-func (s *Stack) AddSubnet(id tcpip.NICID, protocol tcpip.NetworkProtocolNumber, subnet tcpip.Subnet) *tcpip.Error {
+// AddAddressRange adds a range of addresses to the specified NIC. The range is
+// given by a subnet address, and all addresses contained in the subnet are
+// used except for the subnet address itself and the subnet's broadcast
+// address.
+func (s *Stack) AddAddressRange(id tcpip.NICID, protocol tcpip.NetworkProtocolNumber, subnet tcpip.Subnet) *tcpip.Error {
 	s.mu.RLock()
 	defer s.mu.RUnlock()
 
 	if nic, ok := s.nics[id]; ok {
-		nic.AddSubnet(protocol, subnet)
+		nic.AddAddressRange(protocol, subnet)
 		return nil
 	}
 
 	return tcpip.ErrUnknownNICID
 }
 
-// RemoveSubnet removes the subnet range from the specified NIC.
-func (s *Stack) RemoveSubnet(id tcpip.NICID, subnet tcpip.Subnet) *tcpip.Error {
+// RemoveAddressRange removes the range of addresses from the specified NIC.
+func (s *Stack) RemoveAddressRange(id tcpip.NICID, subnet tcpip.Subnet) *tcpip.Error {
 	s.mu.RLock()
 	defer s.mu.RUnlock()
 
 	if nic, ok := s.nics[id]; ok {
-		nic.RemoveSubnet(subnet)
+		nic.RemoveAddressRange(subnet)
 		return nil
 	}
 
 	return tcpip.ErrUnknownNICID
 }
 
-// ContainsSubnet reports whether the specified NIC contains the specified
-// subnet.
-func (s *Stack) ContainsSubnet(id tcpip.NICID, subnet tcpip.Subnet) (bool, *tcpip.Error) {
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-
-	if nic, ok := s.nics[id]; ok {
-		return nic.ContainsSubnet(subnet), nil
-	}
-
-	return false, tcpip.ErrUnknownNICID
-}
-
 // RemoveAddress removes an existing network-layer address from the specified
 // NIC.
 func (s *Stack) RemoveAddress(id tcpip.NICID, addr tcpip.Address) *tcpip.Error {