The network endpoint should not need to have logic to handle different
kinds of neighbor tables. Network endpoints can let the NIC know about
differnt neighbor discovery messages and let the NIC decide which table
to update.
This allows us to remove the LinkAddressCache interface.
PiperOrigin-RevId: 354812584
As per RFC 4861 section 7.3.1,
A neighbor is considered reachable if the node has recently received
a confirmation that packets sent recently to the neighbor were
received by its IP layer. Positive confirmation can be gathered in
two ways: hints from upper-layer protocols that indicate a connection
is making "forward progress", or receipt of a Neighbor Advertisement
message that is a response to a Neighbor Solicitation message.
This change adds support for TCP to let the IP/link layers know that a
neighbor is reachable.
Test: integration_test.TestTCPConfirmNeighborReachability
PiperOrigin-RevId: 354222833
Removes the period of time in which subseqeuent traffic to a Failed neighbor
immediately fails with ErrNoLinkAddress. A Failed neighbor is one in which
address resolution fails; or in other words, the neighbor's IP address cannot
be translated to a MAC address.
This means removing the Failed state for linkAddrCache and allowing transitiong
out of Failed into Incomplete for neighborCache. Previously, both caches would
transition entries to Failed after address resolution fails. In this state, any
subsequent traffic requested within an unreachable time would immediately fail
with ErrNoLinkAddress. This does not follow RFC 4861 section 7.3.3:
If address resolution fails, the entry SHOULD be deleted, so that subsequent
traffic to that neighbor invokes the next-hop determination procedure again.
Invoking next-hop determination at this point ensures that alternate default
routers are tried.
The API for getting a link address for a given address, whether through the link
address cache or the neighbor table, is updated to optionally take a callback
which will be called when address resolution completes. This allows `Route` to
handle completing link resolution internally, so callers of (*Route).Resolve
(e.g. endpoints) don’t have to keep track of when it completes and update the
Route accordingly.
This change also removes the wakers from LinkAddressCache, NeighborCache, and
Route in favor of the callbacks, and callers that previously used a waker can
now just pass a callback to (*Route).Resolve that will notify the waker on
resolution completion.
Fixes#4796
Startblock:
has LGTM from sbalana
and then
add reviewer ghanan
PiperOrigin-RevId: 348597478
Previously, the NIC local address used when completing link resolution
was held in the neighbor entry. A neighbor is not identified by any
NIC local address so remove it.
PiperOrigin-RevId: 338699695
When a Neighbor Solicitation is received, a neighbor entry is created with the
remote host's link layer address, but without a link layer address resolver. If
the host decides to send a packet addressed to the IP address of that neighbor
entry, Address Resolution starts with a nil pointer to the link layer address
resolver. This causes the netstack to panic and crash.
This change ensures that when a packet is sent in that situation, the link
layer address resolver will be set before Address Resolution begins.
Tests:
pkg/tcpip/stack:stack_test
+ TestEntryUnknownToStaleToProbeToReachable
- TestNeighborCacheEntryNoLinkAddress
Updates #1889
Updates #1894
Updates #1895
Updates #1947
Updates #1948
Updates #1949
Updates #1950
PiperOrigin-RevId: 325516471
This change implements the Neighbor Unreachability Detection (NUD) state
machine, as per RFC 4861 [1]. The state machine operates on a single neighbor
in the local network. This requires the state machine to be implemented on each
entry of the neighbor table.
This change also adds, but does not expose, several APIs. The first API is for
performing basic operations on the neighbor table:
- Create a static entry
- List all entries
- Delete all entries
- Remove an entry by address
The second API is used for changing the NUD protocol constants on a per-NIC
basis to allow Neighbor Discovery to operate over links with widely varying
performance characteristics. See [RFC 4861 Section 10][2] for the list of
constants.
Finally, the last API is for allowing users to subscribe to NUD state changes.
See [RFC 4861 Appendix C][3] for the list of edges.
[1]: https://tools.ietf.org/html/rfc4861
[2]: https://tools.ietf.org/html/rfc4861#section-10
[3]: https://tools.ietf.org/html/rfc4861#appendix-C
Tests:
pkg/tcpip/stack:stack_test
- TestNeighborCacheAddStaticEntryThenOverflow
- TestNeighborCacheClear
- TestNeighborCacheClearThenOverflow
- TestNeighborCacheConcurrent
- TestNeighborCacheDuplicateStaticEntryWithDifferentLinkAddress
- TestNeighborCacheDuplicateStaticEntryWithSameLinkAddress
- TestNeighborCacheEntry
- TestNeighborCacheEntryNoLinkAddress
- TestNeighborCacheGetConfig
- TestNeighborCacheKeepFrequentlyUsed
- TestNeighborCacheNotifiesWaker
- TestNeighborCacheOverflow
- TestNeighborCacheOverwriteWithStaticEntryThenOverflow
- TestNeighborCacheRemoveEntry
- TestNeighborCacheRemoveEntryThenOverflow
- TestNeighborCacheRemoveStaticEntry
- TestNeighborCacheRemoveStaticEntryThenOverflow
- TestNeighborCacheRemoveWaker
- TestNeighborCacheReplace
- TestNeighborCacheResolutionFailed
- TestNeighborCacheResolutionTimeout
- TestNeighborCacheSetConfig
- TestNeighborCacheStaticResolution
- TestEntryAddsAndClearsWakers
- TestEntryDelayToProbe
- TestEntryDelayToReachableWhenSolicitedOverrideConfirmation
- TestEntryDelayToReachableWhenUpperLevelConfirmation
- TestEntryDelayToStaleWhenConfirmationWithDifferentAddress
- TestEntryDelayToStaleWhenProbeWithDifferentAddress
- TestEntryFailedGetsDeleted
- TestEntryIncompleteToFailed
- TestEntryIncompleteToIncompleteDoesNotChangeUpdatedAt
- TestEntryIncompleteToReachable
- TestEntryIncompleteToReachableWithRouterFlag
- TestEntryIncompleteToStale
- TestEntryInitiallyUnknown
- TestEntryProbeToFailed
- TestEntryProbeToReachableWhenSolicitedConfirmationWithSameAddress
- TestEntryProbeToReachableWhenSolicitedOverrideConfirmation
- TestEntryProbeToStaleWhenConfirmationWithDifferentAddress
- TestEntryProbeToStaleWhenProbeWithDifferentAddress
- TestEntryReachableToStaleWhenConfirmationWithDifferentAddress
- TestEntryReachableToStaleWhenConfirmationWithDifferentAddressAndOverride
- TestEntryReachableToStaleWhenProbeWithDifferentAddress
- TestEntryReachableToStaleWhenTimeout
- TestEntryStaleToDelay
- TestEntryStaleToReachableWhenSolicitedOverrideConfirmation
- TestEntryStaleToStaleWhenOverrideConfirmation
- TestEntryStaleToStaleWhenProbeUpdateAddress
- TestEntryStaysDelayWhenOverrideConfirmationWithSameAddress
- TestEntryStaysProbeWhenOverrideConfirmationWithSameAddress
- TestEntryStaysReachableWhenConfirmationWithRouterFlag
- TestEntryStaysReachableWhenProbeWithSameAddress
- TestEntryStaysStaleWhenProbeWithSameAddress
- TestEntryUnknownToIncomplete
- TestEntryUnknownToStale
- TestEntryUnknownToUnknownWhenConfirmationWithUnknownAddress
pkg/tcpip/stack:stack_x_test
- TestDefaultNUDConfigurations
- TestNUDConfigurationFailsForNotSupported
- TestNUDConfigurationsBaseReachableTime
- TestNUDConfigurationsDelayFirstProbeTime
- TestNUDConfigurationsMaxMulticastProbes
- TestNUDConfigurationsMaxRandomFactor
- TestNUDConfigurationsMaxUnicastProbes
- TestNUDConfigurationsMinRandomFactor
- TestNUDConfigurationsRetransmitTimer
- TestNUDConfigurationsUnreachableTime
- TestNUDStateReachableTime
- TestNUDStateRecomputeReachableTime
- TestSetNUDConfigurationFailsForBadNICID
- TestSetNUDConfigurationFailsForNotSupported
[1]: https://tools.ietf.org/html/rfc4861
[2]: https://tools.ietf.org/html/rfc4861#section-10
[3]: https://tools.ietf.org/html/rfc4861#appendix-C
Updates #1889
Updates #1894
Updates #1895
Updates #1947
Updates #1948
Updates #1949
Updates #1950
PiperOrigin-RevId: 324070795
Ghanan Gowripalan
Peter Johnston
Tamir Duberstein
Sam Balana