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path: root/pkg/tcpip/stack/stack.go
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2021-02-08Support performing DAD for any addressGhanan Gowripalan
...as long as the network protocol supports duplicate address detection. This CL provides the facilities for a netstack integrator to perform DAD. DHCP recommends that clients effectively perform DAD before accepting an offer. As per RFC 2131 section 4.4.1 pg 38, The client SHOULD perform a check on the suggested address to ensure that the address is not already in use. For example, if the client is on a network that supports ARP, the client may issue an ARP request for the suggested request. The implementation of ARP-based IPv4 DAD effectively operates the same as IPv6's NDP DAD - using ARP requests and responses in place of NDP neighbour solicitations and advertisements, respectively. DAD performed by calls to (*Stack).CheckDuplicateAddress don't interfere with DAD performed when a new IPv6 address is added. This is so that integrator requests to check for duplicate addresses aren't unexpectedly aborted when addresses are removed. A network package internal package provides protocol agnostic DAD state management that specific protocols that provide DAD can use. Fixes #4550. Tests: - internal/ip_test.* - integration_test.TestDAD - arp_test.TestDADARPRequestPacket - ipv6.TestCheckDuplicateAddress PiperOrigin-RevId: 356405593
2021-02-06Remove linkAddrCacheGhanan Gowripalan
It was replaced by NUD/neighborCache. Fixes #4658. PiperOrigin-RevId: 356085221
2021-02-06Remove (*stack.Stack).FindNetworkEndpointGhanan Gowripalan
The network endpoints only look for other network endpoints of the same kind. Since the network protocols keeps track of all endpoints, go through the protocol to find an endpoint with an address instead of the stack. PiperOrigin-RevId: 356051498
2021-02-06Unexpose NICGhanan Gowripalan
The NIC structure is not to be used outside of the stack package directly. PiperOrigin-RevId: 356036737
2021-02-06Check local address directly through NICGhanan Gowripalan
Network endpoints that wish to check addresses on another NIC-local network endpoint may now do so through the NetworkInterface. This fixes a lock ordering issue between NIC removal and link resolution. Before this change: NIC Removal takes the stack lock, neighbor cache lock then neighbor entries' locks. When performing IPv4 link resolution, we take the entry lock then ARP would try check IPv4 local addresses through the stack which tries to obtain the stack's lock. Now that ARP can check IPv4 addreses through the NIC, we avoid the lock ordering issue, while also removing the need for stack to lookup the NIC. PiperOrigin-RevId: 356034245
2021-02-05Refactor locally delivered packetsGhanan Gowripalan
Make it clear that failing to parse a looped back is not a packet sending error but a malformed received packet error. FindNetworkEndpoint returns nil when no network endpoint is found instead of an error. PiperOrigin-RevId: 355954946
2021-02-02Add support for rate limiting out of window ACKs.Bhasker Hariharan
Netstack today will send dupACK's with no rate limit for incoming out of window segments. This can result in ACK loops for example if a TCP socket connects to itself (actually permitted by TCP). Where the ACK sent in response to packets being out of order itself gets considered as an out of window segment resulting in another ACK being generated. PiperOrigin-RevId: 355206877
2021-01-31Default to NUD/neighborCache instead of linkAddrCacheGhanan Gowripalan
This change flips gvisor to use Neighbor unreachability detection by default to populate the neighbor table as defined by RFC 4861 section 7. Although RFC 4861 is targeted at IPv6, the same algorithm is used for link resolution on IPv4 networks using ARP. Integrators may still use the legacy link address cache by setting stack.Options.UseLinkAddrCache to true; stack.Options.UseNeighborCache is now unused and will be removed. A later change will remove linkAddrCache and associated code. Updates #4658. PiperOrigin-RevId: 354850531
2021-01-31Use different neighbor tables per network endpointGhanan Gowripalan
This stores each protocol's neighbor state separately. This change also removes the need for each neighbor entry to keep track of their own link address resolver now that all the entries in a cache will use the same resolver. PiperOrigin-RevId: 354818155
2021-01-31Hide neighbor table kind from NetworkEndpointGhanan Gowripalan
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
2021-01-30Extract route table from Stack lockTamir Duberstein
PiperOrigin-RevId: 354746864
2021-01-30Implement LinkAddressResolver on NetworkEndpointsGhanan Gowripalan
This removes the need to provide the link address request with the NIC the request is being performed on since the NetworkEndpoints already have a reference to the NIC. PiperOrigin-RevId: 354721940
2021-01-28RACK: Update reorder window.Nayana Bidari
After receiving an ACK(cumulative or selective), RACK will update the reorder window which is used as a settling time before marking the packet as lost. This change will add an init function to initialize the variables in RACK and also store the reference to sender in rackControl. The reorder window is calculated as per rfc: https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-7.2 Step 4. PiperOrigin-RevId: 354453528
2021-01-28Change tcpip.Error to an interfaceTamir Duberstein
This makes it possible to add data to types that implement tcpip.Error. ErrBadLinkEndpoint is removed as it is unused. PiperOrigin-RevId: 354437314
2021-01-26Drop nicID from transport endpoint reg/cleanup fnsGhanan Gowripalan
...as it is unused. PiperOrigin-RevId: 353896981
2021-01-26Move SO_SNDBUF to socketops.Nayana Bidari
This CL moves {S,G}etsockopt of SO_SNDBUF from all endpoints to socketops. For unix sockets, we do not support setting of this option. PiperOrigin-RevId: 353871484
2021-01-22Refactor GetMainNICAddressArthur Sfez
It previously returned an error but it could only be UnknownNICID. It now returns a boolean to indicate whether the nic exists or not. PiperOrigin-RevId: 353337489
2021-01-21Resolve static link addresses in GetLinkAddressGhanan Gowripalan
If a network address has a static mapping to a link address, calculate it in GetLinkAddress. Test: stack_test.TestStaticGetLinkAddress PiperOrigin-RevId: 353179616
2021-01-21Only use callback for GetLinkAddressGhanan Gowripalan
GetLinkAddress's callback will be called immediately with a stack.LinkResolutionResult which will hold the link address so no need to also return the link address from the function. Fixes #5151. PiperOrigin-RevId: 353157857
2021-01-19Do not have a stack-wide linkAddressCacheGhanan Gowripalan
Link addresses are cached on a per NIC basis so instead of having a single cache that includes the NIC ID for neighbor entry lookups, use a single cache per NIC. PiperOrigin-RevId: 352684111
2021-01-19Per NIC NetworkEndpoint statisticsArthur Sfez
To facilitate the debugging of multi-homed setup, track Network protocols statistics for each endpoint. Note that the original stack-wide stats still exist. A new type of statistic counter is introduced, which track two versions of a stat at the same time. This lets a network endpoint increment both the local stat and the stack-wide stat at the same time. Fixes #4605 PiperOrigin-RevId: 352663276
2021-01-17Do not use a stack-wide queue of pending packetsGhanan Gowripalan
Packets may be pending on link resolution to complete before being sent. Link resolution is performed for neighbors which are unique to a NIC so hold link resolution related state under the NIC, not the stack. Note, this change may result in more queued packets but that is okay as RFC 4861 section 7.2.2 recommends that the stack maintain a queue of packets for each neighbor that is waiting for link resolution to complete, not a fixed limit per stack. PiperOrigin-RevId: 352322155
2021-01-15Resolve known link address on route creationGhanan Gowripalan
If a Route is being created through a link that requires link address resolution and a remote address that has a known mapping to a link address, populate the link address when the route is created. This removes the need for neighbor/link address caches to perform this check. Fixes #5149 PiperOrigin-RevId: 352122401
2021-01-15Support GetLinkAddress with neighborCacheGhanan Gowripalan
Test: integration_test.TestGetLinkAddress PiperOrigin-RevId: 352119404
2020-12-22Invoke address resolution upon subsequent traffic to Failed neighborPeter Johnston
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
2020-12-16Add support to count the number of packets SACKed.Nayana Bidari
sacked_out is required in RACK to check the number of duplicate acknowledgements during updating the reorder window. If there is no reordering and the value for sacked_out is greater than the classic threshold value 3, then reorder window is set to zero. It is calculated by counting the number of segments sacked in the ACK and is reduced when a cumulative ACK is received which covers the SACK blocks. This value is set to zero when the connection enters recovery. PiperOrigin-RevId: 347872246
2020-11-25Make stack.Route safe to access concurrentlyGhanan Gowripalan
Multiple goroutines may use the same stack.Route concurrently so the stack.Route should make sure that any functions called on it are thread-safe. Fixes #4073 PiperOrigin-RevId: 344320491
2020-11-19Perform IGMPv2 when joining IPv4 multicast groupsRyan Heacock
Added headers, stats, checksum parsing capabilities from RFC 2236 describing IGMPv2. IGMPv2 state machine is implemented for each condition, sending and receiving IGMP Membership Reports and Leave Group messages with backwards compatibility with IGMPv1 routers. Test: * Implemented igmp header parser and checksum calculator in header/igmp_test.go * ipv4/igmp_test.go tests incoming and outgoing IGMP messages and pathways. * Added unit test coverage for IGMPv2 RFC behavior + IGMPv1 backwards compatibility in ipv4/igmp_test.go. Fixes #4682 PiperOrigin-RevId: 343408809
2020-11-19Propagate IP address prefix from host to netstackFabricio Voznika
Closes #4022 PiperOrigin-RevId: 343378647
2020-11-18Fix loopback subnet routing errorGhanan Gowripalan
Packets should be properly routed when sending packets to addresses in the loopback subnet which are not explicitly assigned to the loopback interface. Tests: - integration_test.TestLoopbackAcceptAllInSubnetUDP - integration_test.TestLoopbackAcceptAllInSubnetTCP PiperOrigin-RevId: 343135643
2020-11-18Introduce stack.WritePacketToRemote, remove LinkEndpoint.WriteRawPacketBruno Dal Bo
Redefine stack.WritePacket into stack.WritePacketToRemote which lets the NIC decide whether to append link headers. PiperOrigin-RevId: 343071742
2020-11-13RACK: Detect DSACKNayana Bidari
Detect if the ACK is a duplicate and update in RACK. PiperOrigin-RevId: 342332569
2020-11-12Move packet handling to NetworkEndpointGhanan Gowripalan
The NIC should not hold network-layer state or logic - network packet handling/forwarding should be performed at the network layer instead of the NIC. Fixes #4688 PiperOrigin-RevId: 342166985
2020-11-09net: connect to the ipv4 localhost returns ENETUNREACH if the address isn't setAndrei Vagin
cl/340002915 modified the code to return EADDRNOTAVAIL if connect is called for a localhost address which isn't set. But actually, Linux returns EADDRNOTAVAIL for ipv6 addresses and ENETUNREACH for ipv4 addresses. Updates #4735 PiperOrigin-RevId: 341479129
2020-11-05Use stack.Route exclusively for writing packetsGhanan Gowripalan
* Remove stack.Route from incoming packet path. There is no need to pass around a stack.Route during the incoming path of a packet. Instead, pass around the packet's link/network layer information in the packet buffer since all layers may need this information. * Support address bound and outgoing packet NIC in routes. When forwarding is enabled, the source address of a packet may be bound to a different interface than the outgoing interface. This change updates stack.Route to hold both NICs so that one can be used to write packets while the other is used to check if the route's bound address is valid. Note, we need to hold the address's interface so we can check if the address is a spoofed address. * Introduce the concept of a local route. Local routes are routes where the packet never needs to leave the stack; the destination is stack-local. We can now route between interfaces within a stack if the packet never needs to leave the stack, even when forwarding is disabled. * Always obtain a route from the stack before sending a packet. If a packet needs to be sent in response to an incoming packet, a route must be obtained from the stack to ensure the stack is configured to send packets to the packet's source from the packet's destination. * Enable spoofing if a stack may send packets from unowned addresses. This change required changes to some netgophers since previously, promiscuous mode was enough to let the netstack respond to all incoming packets regardless of the packet's destination address. Now that a stack.Route is not held for each incoming packet, finding a route may fail with local addresses we don't own but accepted packets for while in promiscuous mode. Since we also want to be able to send from any address (in response the received promiscuous mode packets), we need to enable spoofing. * Skip transport layer checksum checks for locally generated packets. If a packet is locally generated, the stack can safely assume that no errors were introduced while being locally routed since the packet is never sent out the wire. Some bugs fixed: - transport layer checksum was never calculated after NAT. - handleLocal didn't handle routing across interfaces. - stack didn't support forwarding across interfaces. - always consult the routing table before creating an endpoint. Updates #4688 Fixes #3906 PiperOrigin-RevId: 340943442
2020-10-31net/tcpip: connect to unset loopback address has to return EADDRNOTAVAILAndrei Vagin
In the docker container, the ipv6 loopback address is not set, and connect("::1") has to return ENEADDRNOTAVAIL in this case. Without this fix, it returns EHOSTUNREACH. PiperOrigin-RevId: 340002915
2020-10-29Keep magic constants out of netstackKevin Krakauer
PiperOrigin-RevId: 339721152
2020-10-27Add basic address deletion to netlinkIan Lewis
Updates #3921 PiperOrigin-RevId: 339195417
2020-10-22Pass NetworkInterface to LinkAddressRequestGhanan Gowripalan
Previously a link endpoint was passed to stack.LinkAddressResolver.LinkAddressRequest. With this change, implementations that want a route for the link address request may find one through the stack. Other implementations that want to send a packet without a route may continue to do so using the network interface directly. Test: - arp_test.TestLinkAddressRequest - ipv6.TestLinkAddressRequest PiperOrigin-RevId: 338577474
2020-10-09Automated rollback of changelist 336304024Ghanan Gowripalan
PiperOrigin-RevId: 336339194
2020-10-09Automated rollback of changelist 336185457Bhasker Hariharan
PiperOrigin-RevId: 336304024
2020-10-08Do not resolve routes immediatelyGhanan Gowripalan
When a response needs to be sent to an incoming packet, the stack should consult its neighbour table to determine the remote address's link address. When an entry does not exist in the stack's neighbor table, the stack should queue the packet while link resolution completes. See comments. PiperOrigin-RevId: 336185457
2020-10-05Remove AssignableAddressEndpoint.NetworkEndpointGhanan Gowripalan
We can get the network endpoint directly from the NIC. This is a preparatory CL for when a Route needs to hold a dedicated NIC as its output interface. This is because when forwarding is enabled, packets may be sent from a NIC different from the NIC a route's local address is associated with. PiperOrigin-RevId: 335484500
2020-09-29Trim Network/Transport Endpoint/ProtocolGhanan Gowripalan
* Remove Capabilities and NICID methods from NetworkEndpoint. * Remove linkEP and stack parameters from NetworkProtocol.NewEndpoint. The LinkEndpoint can be fetched from the NetworkInterface. The stack is passed to the NetworkProtocol when it is created so the NetworkEndpoint can get it from its protocol. * Remove stack parameter from TransportProtocol.NewEndpoint. Like the NetworkProtocol/Endpoint, the stack is passed to the TransportProtocol when it is created. PiperOrigin-RevId: 334332721
2020-09-29Move IP state from NIC to NetworkEndpoint/ProtocolGhanan Gowripalan
* Add network address to network endpoints. Hold network-specific state in the NetworkEndpoint instead of the stack. This results in the stack no longer needing to "know" about the network endpoints and special case certain work for various endpoints (e.g. IPv6 DAD). * Provide NetworkEndpoints with an NetworkInterface interface. Instead of just passing the NIC ID of a NIC, pass an interface so the network endpoint may query other information about the NIC such as whether or not it is a loopback device. * Move NDP code and state to the IPv6 package. NDP is IPv6 specific so there is no need for it to live in the stack. * Control forwarding through NetworkProtocols instead of Stack Forwarding should be controlled on a per-network protocol basis so forwarding configurations are now controlled through network protocols. * Remove stack.referencedNetworkEndpoint. Now that addresses are exposed via AddressEndpoint and only one NetworkEndpoint is created per interface, there is no need for a referenced NetworkEndpoint. * Assume network teardown methods are infallible. Fixes #3871, #3916 PiperOrigin-RevId: 334319433
2020-09-28Support creating protocol instances with Stack refGhanan Gowripalan
Network or transport protocols may want to reach the stack. Support this by letting the stack create the protocol instances so it can pass a reference to itself at protocol creation time. Note, protocols do not yet use the stack in this CL but later CLs will make use of the stack from protocols. PiperOrigin-RevId: 334260210
2020-09-24Change segment/pending queue to use receive buffer limits.Bhasker Hariharan
segment_queue today has its own standalone limit of MaxUnprocessedSegments but this can be a problem in UnlockUser() we do not release the lock till there are segments to be processed. What can happen is as handleSegments dequeues packets more keep getting queued and we will never release the lock. This can keep happening even if the receive buffer is full because nothing can read() till we release the lock. Further having a separate limit for pending segments makes it harder to track memory usage etc. Unifying the limits makes it easier to reason about memory in use and makes the overall buffer behaviour more consistent. PiperOrigin-RevId: 333508122
2020-09-20Merge pull request #3651 from ianlewis:ip-forwardinggVisor bot
PiperOrigin-RevId: 332760843
2020-09-15Don't conclude broadcast from route destinationGhanan Gowripalan
The routing table (in its current) form should not be used to make decisions about whether a remote address is a broadcast address or not (for IPv4). Note, a destination subnet does not always map to a network. E.g. RouterA may have a route to 192.168.0.0/22 through RouterB, but RouterB may be configured with 4x /24 subnets on 4 different interfaces. See https://github.com/google/gvisor/issues/3938. PiperOrigin-RevId: 331819868
2020-09-08Improve type safety for transport protocol optionsGhanan Gowripalan
The existing implementation for TransportProtocol.{Set}Option take arguments of an empty interface type which all types (implicitly) implement; any type may be passed to the functions. This change introduces marker interfaces for transport protocol options that may be set or queried which transport protocol option types implement to ensure that invalid types are caught at compile time. Different interfaces are used to allow the compiler to enforce read-only or set-only socket options. RELNOTES: n/a PiperOrigin-RevId: 330559811