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nic.go
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nic.go
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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package stack
import (
"log"
"reflect"
"sort"
"strings"
"sync/atomic"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
"gvisor.dev/gvisor/pkg/tcpip/header"
"gvisor.dev/gvisor/pkg/tcpip/iptables"
)
var ipv4BroadcastAddr = tcpip.ProtocolAddress{
Protocol: header.IPv4ProtocolNumber,
AddressWithPrefix: tcpip.AddressWithPrefix{
Address: header.IPv4Broadcast,
PrefixLen: 8 * header.IPv4AddressSize,
},
}
// NIC represents a "network interface card" to which the networking stack is
// attached.
type NIC struct {
stack *Stack
id tcpip.NICID
name string
linkEP LinkEndpoint
context NICContext
stats NICStats
mu struct {
sync.RWMutex
enabled bool
spoofing bool
promiscuous bool
primary map[tcpip.NetworkProtocolNumber][]*referencedNetworkEndpoint
endpoints map[NetworkEndpointID]*referencedNetworkEndpoint
addressRanges []tcpip.Subnet
mcastJoins map[NetworkEndpointID]int32
// packetEPs is protected by mu, but the contained PacketEndpoint
// values are not.
packetEPs map[tcpip.NetworkProtocolNumber][]PacketEndpoint
ndp ndpState
}
}
// NICStats includes transmitted and received stats.
type NICStats struct {
Tx DirectionStats
Rx DirectionStats
DisabledRx DirectionStats
}
func makeNICStats() NICStats {
var s NICStats
tcpip.InitStatCounters(reflect.ValueOf(&s).Elem())
return s
}
// DirectionStats includes packet and byte counts.
type DirectionStats struct {
Packets *tcpip.StatCounter
Bytes *tcpip.StatCounter
}
// PrimaryEndpointBehavior is an enumeration of an endpoint's primacy behavior.
type PrimaryEndpointBehavior int
const (
// CanBePrimaryEndpoint indicates the endpoint can be used as a primary
// endpoint for new connections with no local address. This is the
// default when calling NIC.AddAddress.
CanBePrimaryEndpoint PrimaryEndpointBehavior = iota
// FirstPrimaryEndpoint indicates the endpoint should be the first
// primary endpoint considered. If there are multiple endpoints with
// this behavior, the most recently-added one will be first.
FirstPrimaryEndpoint
// NeverPrimaryEndpoint indicates the endpoint should never be a
// primary endpoint.
NeverPrimaryEndpoint
)
// newNIC returns a new NIC using the default NDP configurations from stack.
func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, ctx NICContext) *NIC {
// TODO(b/141011931): Validate a LinkEndpoint (ep) is valid. For
// example, make sure that the link address it provides is a valid
// unicast ethernet address.
// TODO(b/143357959): RFC 8200 section 5 requires that IPv6 endpoints
// observe an MTU of at least 1280 bytes. Ensure that this requirement
// of IPv6 is supported on this endpoint's LinkEndpoint.
nic := &NIC{
stack: stack,
id: id,
name: name,
linkEP: ep,
context: ctx,
stats: makeNICStats(),
}
nic.mu.primary = make(map[tcpip.NetworkProtocolNumber][]*referencedNetworkEndpoint)
nic.mu.endpoints = make(map[NetworkEndpointID]*referencedNetworkEndpoint)
nic.mu.mcastJoins = make(map[NetworkEndpointID]int32)
nic.mu.packetEPs = make(map[tcpip.NetworkProtocolNumber][]PacketEndpoint)
nic.mu.ndp = ndpState{
nic: nic,
configs: stack.ndpConfigs,
dad: make(map[tcpip.Address]dadState),
defaultRouters: make(map[tcpip.Address]defaultRouterState),
onLinkPrefixes: make(map[tcpip.Subnet]onLinkPrefixState),
autoGenAddresses: make(map[tcpip.Address]autoGenAddressState),
}
// Register supported packet endpoint protocols.
for _, netProto := range header.Ethertypes {
nic.mu.packetEPs[netProto] = []PacketEndpoint{}
}
for _, netProto := range stack.networkProtocols {
nic.mu.packetEPs[netProto.Number()] = []PacketEndpoint{}
}
nic.linkEP.Attach(nic)
return nic
}
// enabled returns true if n is enabled.
func (n *NIC) enabled() bool {
n.mu.RLock()
enabled := n.mu.enabled
n.mu.RUnlock()
return enabled
}
// disable disables n.
//
// It undoes the work done by enable.
func (n *NIC) disable() *tcpip.Error {
n.mu.RLock()
enabled := n.mu.enabled
n.mu.RUnlock()
if !enabled {
return nil
}
n.mu.Lock()
defer n.mu.Unlock()
if !n.mu.enabled {
return nil
}
// TODO(b/147015577): Should Routes that are currently bound to n be
// invalidated? Currently, Routes will continue to work when a NIC is enabled
// again, and applications may not know that the underlying NIC was ever
// disabled.
if _, ok := n.stack.networkProtocols[header.IPv6ProtocolNumber]; ok {
n.mu.ndp.stopSolicitingRouters()
n.mu.ndp.cleanupState(false /* hostOnly */)
// Stop DAD for all the unicast IPv6 endpoints that are in the
// permanentTentative state.
for _, r := range n.mu.endpoints {
if addr := r.ep.ID().LocalAddress; r.getKind() == permanentTentative && header.IsV6UnicastAddress(addr) {
n.mu.ndp.stopDuplicateAddressDetection(addr)
}
}
// The NIC may have already left the multicast group.
if err := n.leaveGroupLocked(header.IPv6AllNodesMulticastAddress); err != nil && err != tcpip.ErrBadLocalAddress {
return err
}
}
if _, ok := n.stack.networkProtocols[header.IPv4ProtocolNumber]; ok {
// The address may have already been removed.
if err := n.removePermanentAddressLocked(ipv4BroadcastAddr.AddressWithPrefix.Address); err != nil && err != tcpip.ErrBadLocalAddress {
return err
}
}
n.mu.enabled = false
return nil
}
// enable enables n.
//
// If the stack has IPv6 enabled, enable will join the IPv6 All-Nodes Multicast
// address (ff02::1), start DAD for permanent addresses, and start soliciting
// routers if the stack is not operating as a router. If the stack is also
// configured to auto-generate a link-local address, one will be generated.
func (n *NIC) enable() *tcpip.Error {
n.mu.RLock()
enabled := n.mu.enabled
n.mu.RUnlock()
if enabled {
return nil
}
n.mu.Lock()
defer n.mu.Unlock()
if n.mu.enabled {
return nil
}
n.mu.enabled = true
// Create an endpoint to receive broadcast packets on this interface.
if _, ok := n.stack.networkProtocols[header.IPv4ProtocolNumber]; ok {
if _, err := n.addAddressLocked(ipv4BroadcastAddr, NeverPrimaryEndpoint, permanent, static, false /* deprecated */); err != nil {
return err
}
}
// Join the IPv6 All-Nodes Multicast group if the stack is configured to
// use IPv6. This is required to ensure that this node properly receives
// and responds to the various NDP messages that are destined to the
// all-nodes multicast address. An example is the Neighbor Advertisement
// when we perform Duplicate Address Detection, or Router Advertisement
// when we do Router Discovery. See RFC 4862, section 5.4.2 and RFC 4861
// section 4.2 for more information.
//
// Also auto-generate an IPv6 link-local address based on the NIC's
// link address if it is configured to do so. Note, each interface is
// required to have IPv6 link-local unicast address, as per RFC 4291
// section 2.1.
_, ok := n.stack.networkProtocols[header.IPv6ProtocolNumber]
if !ok {
return nil
}
// Join the All-Nodes multicast group before starting DAD as responses to DAD
// (NDP NS) messages may be sent to the All-Nodes multicast group if the
// source address of the NDP NS is the unspecified address, as per RFC 4861
// section 7.2.4.
if err := n.joinGroupLocked(header.IPv6ProtocolNumber, header.IPv6AllNodesMulticastAddress); err != nil {
return err
}
// Perform DAD on the all the unicast IPv6 endpoints that are in the permanent
// state.
//
// Addresses may have aleady completed DAD but in the time since the NIC was
// last enabled, other devices may have acquired the same addresses.
for _, r := range n.mu.endpoints {
addr := r.ep.ID().LocalAddress
if k := r.getKind(); (k != permanent && k != permanentTentative) || !header.IsV6UnicastAddress(addr) {
continue
}
r.setKind(permanentTentative)
if err := n.mu.ndp.startDuplicateAddressDetection(addr, r); err != nil {
return err
}
}
// Do not auto-generate an IPv6 link-local address for loopback devices.
if n.stack.autoGenIPv6LinkLocal && !n.isLoopback() {
// The valid and preferred lifetime is infinite for the auto-generated
// link-local address.
n.mu.ndp.doSLAAC(header.IPv6LinkLocalPrefix.Subnet(), header.NDPInfiniteLifetime, header.NDPInfiniteLifetime)
}
// If we are operating as a router, then do not solicit routers since we
// won't process the RAs anyways.
//
// Routers do not process Router Advertisements (RA) the same way a host
// does. That is, routers do not learn from RAs (e.g. on-link prefixes
// and default routers). Therefore, soliciting RAs from other routers on
// a link is unnecessary for routers.
if !n.stack.forwarding {
n.mu.ndp.startSolicitingRouters()
}
return nil
}
// remove detaches NIC from the link endpoint, and marks existing referenced
// network endpoints expired. This guarantees no packets between this NIC and
// the network stack.
func (n *NIC) remove() *tcpip.Error {
n.mu.Lock()
defer n.mu.Unlock()
// Detach from link endpoint, so no packet comes in.
n.linkEP.Attach(nil)
// Remove permanent and permanentTentative addresses, so no packet goes out.
var errs []*tcpip.Error
for nid, ref := range n.mu.endpoints {
switch ref.getKind() {
case permanentTentative, permanent:
if err := n.removePermanentAddressLocked(nid.LocalAddress); err != nil {
errs = append(errs, err)
}
}
}
if len(errs) > 0 {
return errs[0]
}
return nil
}
// becomeIPv6Router transitions n into an IPv6 router.
//
// When transitioning into an IPv6 router, host-only state (NDP discovered
// routers, discovered on-link prefixes, and auto-generated addresses) will
// be cleaned up/invalidated and NDP router solicitations will be stopped.
func (n *NIC) becomeIPv6Router() {
n.mu.Lock()
defer n.mu.Unlock()
n.mu.ndp.cleanupState(true /* hostOnly */)
n.mu.ndp.stopSolicitingRouters()
}
// becomeIPv6Host transitions n into an IPv6 host.
//
// When transitioning into an IPv6 host, NDP router solicitations will be
// started.
func (n *NIC) becomeIPv6Host() {
n.mu.Lock()
defer n.mu.Unlock()
n.mu.ndp.startSolicitingRouters()
}
// setPromiscuousMode enables or disables promiscuous mode.
func (n *NIC) setPromiscuousMode(enable bool) {
n.mu.Lock()
n.mu.promiscuous = enable
n.mu.Unlock()
}
func (n *NIC) isPromiscuousMode() bool {
n.mu.RLock()
rv := n.mu.promiscuous
n.mu.RUnlock()
return rv
}
func (n *NIC) isLoopback() bool {
return n.linkEP.Capabilities()&CapabilityLoopback != 0
}
// setSpoofing enables or disables address spoofing.
func (n *NIC) setSpoofing(enable bool) {
n.mu.Lock()
n.mu.spoofing = enable
n.mu.Unlock()
}
// primaryEndpoint will return the first non-deprecated endpoint if such an
// endpoint exists for the given protocol and remoteAddr. If no non-deprecated
// endpoint exists, the first deprecated endpoint will be returned.
//
// If an IPv6 primary endpoint is requested, Source Address Selection (as
// defined by RFC 6724 section 5) will be performed.
func (n *NIC) primaryEndpoint(protocol tcpip.NetworkProtocolNumber, remoteAddr tcpip.Address) *referencedNetworkEndpoint {
if protocol == header.IPv6ProtocolNumber && remoteAddr != "" {
return n.primaryIPv6Endpoint(remoteAddr)
}
n.mu.RLock()
defer n.mu.RUnlock()
var deprecatedEndpoint *referencedNetworkEndpoint
for _, r := range n.mu.primary[protocol] {
if !r.isValidForOutgoingRLocked() {
continue
}
if !r.deprecated {
if r.tryIncRef() {
// r is not deprecated, so return it immediately.
//
// If we kept track of a deprecated endpoint, decrement its reference
// count since it was incremented when we decided to keep track of it.
if deprecatedEndpoint != nil {
deprecatedEndpoint.decRefLocked()
deprecatedEndpoint = nil
}
return r
}
} else if deprecatedEndpoint == nil && r.tryIncRef() {
// We prefer an endpoint that is not deprecated, but we keep track of r in
// case n doesn't have any non-deprecated endpoints.
//
// If we end up finding a more preferred endpoint, r's reference count
// will be decremented when such an endpoint is found.
deprecatedEndpoint = r
}
}
// n doesn't have any valid non-deprecated endpoints, so return
// deprecatedEndpoint (which may be nil if n doesn't have any valid deprecated
// endpoints either).
return deprecatedEndpoint
}
// ipv6AddrCandidate is an IPv6 candidate for Source Address Selection (RFC
// 6724 section 5).
type ipv6AddrCandidate struct {
ref *referencedNetworkEndpoint
scope header.IPv6AddressScope
}
// primaryIPv6Endpoint returns an IPv6 endpoint following Source Address
// Selection (RFC 6724 section 5).
//
// Note, only rules 1-3 are followed.
//
// remoteAddr must be a valid IPv6 address.
func (n *NIC) primaryIPv6Endpoint(remoteAddr tcpip.Address) *referencedNetworkEndpoint {
n.mu.RLock()
defer n.mu.RUnlock()
primaryAddrs := n.mu.primary[header.IPv6ProtocolNumber]
if len(primaryAddrs) == 0 {
return nil
}
// Create a candidate set of available addresses we can potentially use as a
// source address.
cs := make([]ipv6AddrCandidate, 0, len(primaryAddrs))
for _, r := range primaryAddrs {
// If r is not valid for outgoing connections, it is not a valid endpoint.
if !r.isValidForOutgoingRLocked() {
continue
}
addr := r.ep.ID().LocalAddress
scope, err := header.ScopeForIPv6Address(addr)
if err != nil {
// Should never happen as we got r from the primary IPv6 endpoint list and
// ScopeForIPv6Address only returns an error if addr is not an IPv6
// address.
log.Fatalf("header.ScopeForIPv6Address(%s): %s", addr, err)
}
cs = append(cs, ipv6AddrCandidate{
ref: r,
scope: scope,
})
}
remoteScope, err := header.ScopeForIPv6Address(remoteAddr)
if err != nil {
// primaryIPv6Endpoint should never be called with an invalid IPv6 address.
log.Fatalf("header.ScopeForIPv6Address(%s): %s", remoteAddr, err)
}
// Sort the addresses as per RFC 6724 section 5 rules 1-3.
//
// TODO(b/146021396): Implement rules 4-8 of RFC 6724 section 5.
sort.Slice(cs, func(i, j int) bool {
sa := cs[i]
sb := cs[j]
// Prefer same address as per RFC 6724 section 5 rule 1.
if sa.ref.ep.ID().LocalAddress == remoteAddr {
return true
}
if sb.ref.ep.ID().LocalAddress == remoteAddr {
return false
}
// Prefer appropriate scope as per RFC 6724 section 5 rule 2.
if sa.scope < sb.scope {
return sa.scope >= remoteScope
} else if sb.scope < sa.scope {
return sb.scope < remoteScope
}
// Avoid deprecated addresses as per RFC 6724 section 5 rule 3.
if saDep, sbDep := sa.ref.deprecated, sb.ref.deprecated; saDep != sbDep {
// If sa is not deprecated, it is preferred over sb.
return sbDep
}
// sa and sb are equal, return the endpoint that is closest to the front of
// the primary endpoint list.
return i < j
})
// Return the most preferred address that can have its reference count
// incremented.
for _, c := range cs {
if r := c.ref; r.tryIncRef() {
return r
}
}
return nil
}
// hasPermanentAddrLocked returns true if n has a permanent (including currently
// tentative) address, addr.
func (n *NIC) hasPermanentAddrLocked(addr tcpip.Address) bool {
ref, ok := n.mu.endpoints[NetworkEndpointID{addr}]
if !ok {
return false
}
kind := ref.getKind()
return kind == permanent || kind == permanentTentative
}
type getRefBehaviour int
const (
// spoofing indicates that the NIC's spoofing flag should be observed when
// getting a NIC's referenced network endpoint.
spoofing getRefBehaviour = iota
// promiscuous indicates that the NIC's promiscuous flag should be observed
// when getting a NIC's referenced network endpoint.
promiscuous
// forceSpoofing indicates that the NIC should be assumed to be spoofing,
// regardless of what the NIC's spoofing flag is when getting a NIC's
// referenced network endpoint.
forceSpoofing
)
func (n *NIC) getRef(protocol tcpip.NetworkProtocolNumber, dst tcpip.Address) *referencedNetworkEndpoint {
return n.getRefOrCreateTemp(protocol, dst, CanBePrimaryEndpoint, promiscuous)
}
// findEndpoint finds the endpoint, if any, with the given address.
func (n *NIC) findEndpoint(protocol tcpip.NetworkProtocolNumber, address tcpip.Address, peb PrimaryEndpointBehavior) *referencedNetworkEndpoint {
return n.getRefOrCreateTemp(protocol, address, peb, spoofing)
}
// getRefEpOrCreateTemp returns the referenced network endpoint for the given
// protocol and address.
//
// If none exists a temporary one may be created if we are in promiscuous mode
// or spoofing. Promiscuous mode will only be checked if promiscuous is true.
// Similarly, spoofing will only be checked if spoofing is true.
func (n *NIC) getRefOrCreateTemp(protocol tcpip.NetworkProtocolNumber, address tcpip.Address, peb PrimaryEndpointBehavior, tempRef getRefBehaviour) *referencedNetworkEndpoint {
id := NetworkEndpointID{address}
n.mu.RLock()
var spoofingOrPromiscuous bool
switch tempRef {
case spoofing:
spoofingOrPromiscuous = n.mu.spoofing
case promiscuous:
spoofingOrPromiscuous = n.mu.promiscuous
case forceSpoofing:
spoofingOrPromiscuous = true
}
if ref, ok := n.mu.endpoints[id]; ok {
// An endpoint with this id exists, check if it can be used and return it.
switch ref.getKind() {
case permanentExpired:
if !spoofingOrPromiscuous {
n.mu.RUnlock()
return nil
}
fallthrough
case temporary, permanent:
if ref.tryIncRef() {
n.mu.RUnlock()
return ref
}
}
}
// A usable reference was not found, create a temporary one if requested by
// the caller or if the address is found in the NIC's subnets.
createTempEP := spoofingOrPromiscuous
if !createTempEP {
for _, sn := range n.mu.addressRanges {
// Skip the subnet address.
if address == sn.ID() {
continue
}
// For now just skip the broadcast address, until we support it.
// FIXME(b/137608825): Add support for sending/receiving directed
// (subnet) broadcast.
if address == sn.Broadcast() {
continue
}
if sn.Contains(address) {
createTempEP = true
break
}
}
}
n.mu.RUnlock()
if !createTempEP {
return nil
}
// Try again with the lock in exclusive mode. If we still can't get the
// endpoint, create a new "temporary" endpoint. It will only exist while
// there's a route through it.
n.mu.Lock()
if ref, ok := n.mu.endpoints[id]; ok {
// No need to check the type as we are ok with expired endpoints at this
// point.
if ref.tryIncRef() {
n.mu.Unlock()
return ref
}
// tryIncRef failing means the endpoint is scheduled to be removed once the
// lock is released. Remove it here so we can create a new (temporary) one.
// The removal logic waiting for the lock handles this case.
n.removeEndpointLocked(ref)
}
// Add a new temporary endpoint.
netProto, ok := n.stack.networkProtocols[protocol]
if !ok {
n.mu.Unlock()
return nil
}
ref, _ := n.addAddressLocked(tcpip.ProtocolAddress{
Protocol: protocol,
AddressWithPrefix: tcpip.AddressWithPrefix{
Address: address,
PrefixLen: netProto.DefaultPrefixLen(),
},
}, peb, temporary, static, false)
n.mu.Unlock()
return ref
}
// addAddressLocked adds a new protocolAddress to n.
//
// If n already has the address in a non-permanent state, and the kind given is
// permanent, that address will be promoted in place and its properties set to
// the properties provided. Otherwise, it returns tcpip.ErrDuplicateAddress.
func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior, kind networkEndpointKind, configType networkEndpointConfigType, deprecated bool) (*referencedNetworkEndpoint, *tcpip.Error) {
// TODO(b/141022673): Validate IP addresses before adding them.
// Sanity check.
id := NetworkEndpointID{LocalAddress: protocolAddress.AddressWithPrefix.Address}
if ref, ok := n.mu.endpoints[id]; ok {
// Endpoint already exists.
if kind != permanent {
return nil, tcpip.ErrDuplicateAddress
}
switch ref.getKind() {
case permanentTentative, permanent:
// The NIC already have a permanent endpoint with that address.
return nil, tcpip.ErrDuplicateAddress
case permanentExpired, temporary:
// Promote the endpoint to become permanent and respect the new peb,
// configType and deprecated status.
if ref.tryIncRef() {
// TODO(b/147748385): Perform Duplicate Address Detection when promoting
// an IPv6 endpoint to permanent.
ref.setKind(permanent)
ref.deprecated = deprecated
ref.configType = configType
refs := n.mu.primary[ref.protocol]
for i, r := range refs {
if r == ref {
switch peb {
case CanBePrimaryEndpoint:
return ref, nil
case FirstPrimaryEndpoint:
if i == 0 {
return ref, nil
}
n.mu.primary[r.protocol] = append(refs[:i], refs[i+1:]...)
case NeverPrimaryEndpoint:
n.mu.primary[r.protocol] = append(refs[:i], refs[i+1:]...)
return ref, nil
}
}
}
n.insertPrimaryEndpointLocked(ref, peb)
return ref, nil
}
// tryIncRef failing means the endpoint is scheduled to be removed once
// the lock is released. Remove it here so we can create a new
// (permanent) one. The removal logic waiting for the lock handles this
// case.
n.removeEndpointLocked(ref)
}
}
netProto, ok := n.stack.networkProtocols[protocolAddress.Protocol]
if !ok {
return nil, tcpip.ErrUnknownProtocol
}
// Create the new network endpoint.
ep, err := netProto.NewEndpoint(n.id, protocolAddress.AddressWithPrefix, n.stack, n, n.linkEP, n.stack)
if err != nil {
return nil, err
}
isIPv6Unicast := protocolAddress.Protocol == header.IPv6ProtocolNumber && header.IsV6UnicastAddress(protocolAddress.AddressWithPrefix.Address)
// If the address is an IPv6 address and it is a permanent address,
// mark it as tentative so it goes through the DAD process if the NIC is
// enabled. If the NIC is not enabled, DAD will be started when the NIC is
// enabled.
if isIPv6Unicast && kind == permanent {
kind = permanentTentative
}
ref := &referencedNetworkEndpoint{
refs: 1,
ep: ep,
nic: n,
protocol: protocolAddress.Protocol,
kind: kind,
configType: configType,
deprecated: deprecated,
}
// Set up cache if link address resolution exists for this protocol.
if n.linkEP.Capabilities()&CapabilityResolutionRequired != 0 {
if _, ok := n.stack.linkAddrResolvers[protocolAddress.Protocol]; ok {
ref.linkCache = n.stack
}
}
// If we are adding an IPv6 unicast address, join the solicited-node
// multicast address.
if isIPv6Unicast {
snmc := header.SolicitedNodeAddr(protocolAddress.AddressWithPrefix.Address)
if err := n.joinGroupLocked(protocolAddress.Protocol, snmc); err != nil {
return nil, err
}
}
n.mu.endpoints[id] = ref
n.insertPrimaryEndpointLocked(ref, peb)
// If we are adding a tentative IPv6 address, start DAD if the NIC is enabled.
if isIPv6Unicast && kind == permanentTentative && n.mu.enabled {
if err := n.mu.ndp.startDuplicateAddressDetection(protocolAddress.AddressWithPrefix.Address, ref); err != nil {
return nil, err
}
}
return ref, nil
}
// AddAddress adds a new address to n, so that it starts accepting packets
// targeted at the given address (and network protocol).
func (n *NIC) AddAddress(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior) *tcpip.Error {
// Add the endpoint.
n.mu.Lock()
_, err := n.addAddressLocked(protocolAddress, peb, permanent, static, false /* deprecated */)
n.mu.Unlock()
return err
}
// AllAddresses returns all addresses (primary and non-primary) associated with
// this NIC.
func (n *NIC) AllAddresses() []tcpip.ProtocolAddress {
n.mu.RLock()
defer n.mu.RUnlock()
addrs := make([]tcpip.ProtocolAddress, 0, len(n.mu.endpoints))
for nid, ref := range n.mu.endpoints {
// Don't include tentative, expired or temporary endpoints to
// avoid confusion and prevent the caller from using those.
switch ref.getKind() {
case permanentExpired, temporary:
continue
}
addrs = append(addrs, tcpip.ProtocolAddress{
Protocol: ref.protocol,
AddressWithPrefix: tcpip.AddressWithPrefix{
Address: nid.LocalAddress,
PrefixLen: ref.ep.PrefixLen(),
},
})
}
return addrs
}
// PrimaryAddresses returns the primary addresses associated with this NIC.
func (n *NIC) PrimaryAddresses() []tcpip.ProtocolAddress {
n.mu.RLock()
defer n.mu.RUnlock()
var addrs []tcpip.ProtocolAddress
for proto, list := range n.mu.primary {
for _, ref := range list {
// Don't include tentative, expired or tempory endpoints
// to avoid confusion and prevent the caller from using
// those.
switch ref.getKind() {
case permanentTentative, permanentExpired, temporary:
continue
}
addrs = append(addrs, tcpip.ProtocolAddress{
Protocol: proto,
AddressWithPrefix: tcpip.AddressWithPrefix{
Address: ref.ep.ID().LocalAddress,
PrefixLen: ref.ep.PrefixLen(),
},
})
}
}
return addrs
}
// primaryAddress returns the primary address associated with this NIC.
//
// primaryAddress will return the first non-deprecated address if such an
// address exists. If no non-deprecated address exists, the first deprecated
// address will be returned.
func (n *NIC) primaryAddress(proto tcpip.NetworkProtocolNumber) tcpip.AddressWithPrefix {
n.mu.RLock()
defer n.mu.RUnlock()
list, ok := n.mu.primary[proto]
if !ok {
return tcpip.AddressWithPrefix{}
}
var deprecatedEndpoint *referencedNetworkEndpoint
for _, ref := range list {
// Don't include tentative, expired or tempory endpoints to avoid confusion
// and prevent the caller from using those.
switch ref.getKind() {
case permanentTentative, permanentExpired, temporary:
continue
}
if !ref.deprecated {
return tcpip.AddressWithPrefix{
Address: ref.ep.ID().LocalAddress,
PrefixLen: ref.ep.PrefixLen(),
}
}
if deprecatedEndpoint == nil {
deprecatedEndpoint = ref
}
}
if deprecatedEndpoint != nil {
return tcpip.AddressWithPrefix{
Address: deprecatedEndpoint.ep.ID().LocalAddress,
PrefixLen: deprecatedEndpoint.ep.PrefixLen(),
}
}
return tcpip.AddressWithPrefix{}
}
// AddAddressRange adds a range of addresses to n, so that it starts accepting
// packets targeted at the given addresses and network protocol. 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 (n *NIC) AddAddressRange(protocol tcpip.NetworkProtocolNumber, subnet tcpip.Subnet) {
n.mu.Lock()
n.mu.addressRanges = append(n.mu.addressRanges, subnet)
n.mu.Unlock()
}
// RemoveAddressRange removes the given address range from n.
func (n *NIC) RemoveAddressRange(subnet tcpip.Subnet) {
n.mu.Lock()
// Use the same underlying array.
tmp := n.mu.addressRanges[:0]
for _, sub := range n.mu.addressRanges {
if sub != subnet {
tmp = append(tmp, sub)
}
}
n.mu.addressRanges = tmp
n.mu.Unlock()
}
// AddressRanges returns the Subnets associated with this NIC.
func (n *NIC) AddressRanges() []tcpip.Subnet {
n.mu.RLock()
defer n.mu.RUnlock()
sns := make([]tcpip.Subnet, 0, len(n.mu.addressRanges)+len(n.mu.endpoints))
for nid := range n.mu.endpoints {
sn, err := tcpip.NewSubnet(nid.LocalAddress, tcpip.AddressMask(strings.Repeat("\xff", len(nid.LocalAddress))))
if err != nil {
// This should never happen as the mask has been carefully crafted to
// match the address.
panic("Invalid endpoint subnet: " + err.Error())
}
sns = append(sns, sn)
}
return append(sns, n.mu.addressRanges...)
}
// insertPrimaryEndpointLocked adds r to n's primary endpoint list as required
// by peb.
//
// n MUST be locked.
func (n *NIC) insertPrimaryEndpointLocked(r *referencedNetworkEndpoint, peb PrimaryEndpointBehavior) {
switch peb {
case CanBePrimaryEndpoint:
n.mu.primary[r.protocol] = append(n.mu.primary[r.protocol], r)
case FirstPrimaryEndpoint:
n.mu.primary[r.protocol] = append([]*referencedNetworkEndpoint{r}, n.mu.primary[r.protocol]...)
}
}
func (n *NIC) removeEndpointLocked(r *referencedNetworkEndpoint) {
id := *r.ep.ID()
// Nothing to do if the reference has already been replaced with a different
// one. This happens in the case where 1) this endpoint's ref count hit zero
// and was waiting (on the lock) to be removed and 2) the same address was
// re-added in the meantime by removing this endpoint from the list and
// adding a new one.
if n.mu.endpoints[id] != r {
return
}
if r.getKind() == permanent {
panic("Reference count dropped to zero before being removed")
}
delete(n.mu.endpoints, id)
refs := n.mu.primary[r.protocol]
for i, ref := range refs {
if ref == r {
n.mu.primary[r.protocol] = append(refs[:i], refs[i+1:]...)
break
}
}
r.ep.Close()
}
func (n *NIC) removeEndpoint(r *referencedNetworkEndpoint) {
n.mu.Lock()
n.removeEndpointLocked(r)
n.mu.Unlock()
}
func (n *NIC) removePermanentAddressLocked(addr tcpip.Address) *tcpip.Error {
r, ok := n.mu.endpoints[NetworkEndpointID{addr}]
if !ok {
return tcpip.ErrBadLocalAddress
}
kind := r.getKind()
if kind != permanent && kind != permanentTentative {
return tcpip.ErrBadLocalAddress
}
isIPv6Unicast := r.protocol == header.IPv6ProtocolNumber && header.IsV6UnicastAddress(addr)
if isIPv6Unicast {
// If we are removing a tentative IPv6 unicast address, stop