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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
2020-11-11Teach netstack how to add options to IPv4 packetsJulian Elischer
Most packets don't have options but they are an integral part of the standard. Teaching the ipv4 code how to handle them will simplify future testing and use. Because Options are so rare it is worth making sure that the extra work is kept out of the fast path as much as possible. Prior to this change, all usages of the IHL field of the IPv4Fields/Encode system set it to the same constant value except in a couple of tests for bad values. From this change IHL will not be a constant as it will depend on the size of any Options. Since ipv4.Encode() now handles the options it becomes a possible source of errors to let the callers set this value, so remove it entirely and calculate the value from the size of the Options if present (or not) therefore guaranteeing a correct value. Fixes #4709 RELNOTES: n/a PiperOrigin-RevId: 341864765
2020-11-09Skip `EventHUp` notify in `FIN_WAIT2` on a socket close.Mithun Iyer
This Notify was added as part of cl/279106406; but notifying `EventHUp` in `FIN_WAIT2` is incorrect, as we want to only notify later on `TIME_WAIT` or a reset. However, we do need to notify any blocked waiters of an activity on the endpoint with `EventIn`|`EventOut`. PiperOrigin-RevId: 341490913
2020-11-06Return early in walkSACK if segment has no SACK blocks.Bhasker Hariharan
This avoids a needless allocation. Updates #231 PiperOrigin-RevId: 341113160
2020-11-06Do not send to the zero portGhanan Gowripalan
Port 0 is not meant to identify any remote port so attempting to send a packet to it should return an error. PiperOrigin-RevId: 341009528
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
2020-11-04Unlock tcp endpoint mutex before blocking forever.Dean Deng
This was occasionally causing tests to get stuck due to races with the save process, during which the same mutex is acquired. PiperOrigin-RevId: 340789616
2020-11-03Release mutex before blocking during TCP handshake route resolution.Dean Deng
Without releasing the mutex, operations on the endpoint following a nonblocking connect will not make progress until connect is complete. PiperOrigin-RevId: 340467654
2020-11-02Automated rollback of changelist 339945377Dean Deng
PiperOrigin-RevId: 340274194
2020-10-30Automated rollback of changelist 339750876Dean Deng
PiperOrigin-RevId: 339945377
2020-10-29Automated rollback of changelist 339675182Dean Deng
PiperOrigin-RevId: 339750876
2020-10-29Fix TCP wildcard bind failure when netstack is v6 onlyTing-Yu Wang
TCP endpoint unconditionly binds to v4 even when the stack only supports v6. PiperOrigin-RevId: 339739392
2020-10-29Delay goroutine creation during TCP handshake for accept/connect.Dean Deng
Refactor TCP handshake code so that when connect is initiated, the initial SYN is sent before creating a goroutine to handle the rest of the handshake (which blocks). Similarly, the initial SYN-ACK is sent inline when SYN is received during accept. Some additional cleanup is done as well. Eventually we would like to complete connections in the dispatcher without requiring a wakeup to complete the handshake. This refactor makes that easier. Updates #231 PiperOrigin-RevId: 339675182
2020-10-27Add support for Timestamp and RecordRoute IP optionsJulian Elischer
IPv4 options extend the size of the IP header and have a basic known format. The framework can process that format without needing to know about every possible option. We can add more code to handle additional option types as we need them. Bad options or mangled option entries can result in ICMP Parameter Problem packets. The first types we support are the Timestamp option and the Record Route option, included in this change. The options are processed at several points in the packet flow within the Network stack, with slightly different requirements. The framework includes a mechanism to control this at each point. Support has been added for such points which are only present in upcoming CLs such as during packet forwarding and fragmentation. With this change, 'ping -R' and 'ping -T' work against gVisor and Fuchsia. $ ping -R 192.168.1.2 PING 192.168.1.2 (192.168.1.2) 56(124) bytes of data. 64 bytes from 192.168.1.2: icmp_seq=1 ttl=64 time=0.990 ms NOP RR: 192.168.1.1 192.168.1.2 192.168.1.1 $ ping -T tsprespec 192.168.1.2 192.168.1.1 192.168.1.2 PING 192.168.1.2 (192.168.1.2) 56(124) bytes of data. 64 bytes from 192.168.1.2: icmp_seq=1 ttl=64 time=1.20 ms TS: 192.168.1.2 71486821 absolute 192.168.1.1 746 Unit tests included for generic options, Timestamp options and Record Route options. PiperOrigin-RevId: 339379076
2020-10-27Wake up any waiters on an ICMP error on UDP socket.Bhasker Hariharan
This change wakes up any waiters when we receive an ICMP port unreachable control packet on an UDP socket as well as sets waiter.EventErr in the result returned by Readiness() when e.lastError is not nil. The latter is required where an epoll()/poll() is done after the error is already handled since we will never notify again in such cases. PiperOrigin-RevId: 339370469
2020-10-23Fix TestTCPTimeWaitNewSyn.Bhasker Hariharan
Drain the notification channel after first accept as in case the first accept never blocked then the notification for the first accept will still be in the channel causing the second accept to fail as it will try to wait on the channel and return immediately due to the older notification even though there is no connection yet in the accept queue. PiperOrigin-RevId: 338710062
2020-10-23Support getsockopt for SO_ACCEPTCONN.Nayana Bidari
The SO_ACCEPTCONN option is used only on getsockopt(). When this option is specified, getsockopt() indicates whether socket listening is enabled for the socket. A value of zero indicates that socket listening is disabled; non-zero that it is enabled. PiperOrigin-RevId: 338703206
2020-10-23Decrement e.synRcvdCount once handshake is complete.Bhasker Hariharan
Earlier the count was dropped only after calling e.deliverAccepted. This lead to an issue where there were no connections in SYN-RCVD state for the listening endpoint but e.synRcvdCount would not be zero because it was being reduced only when handleSynSegment returned after deliverAccepted returned. This issue is seen when the Nth SYN for a listen backlog of size N which would cause the listen backlog to be full gets dropped occasionally. This happens when the new SYN comes at when the previous completed endpoint has been delivered to the accept queue but the synRcvdCount hasn't yet been decremented because the goroutine running handleSynSegment has not yet completed. PiperOrigin-RevId: 338690646
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
2020-10-20Fix nogo test in //pkg/tcpip/...Ting-Yu Wang
PiperOrigin-RevId: 338168977
2020-10-20Fix nogo tests.Ting-Yu Wang
//pkg/tcpip/stack:stack_x_test_nogo //pkg/tcpip/transport/raw:raw_nogo PiperOrigin-RevId: 338153265
2020-10-11Assign ep.effectiveNetProtos in UDP forwarder's CreateEndpointpatr0nus
2020-10-09TCP Receive window advertisement fixes.Bhasker Hariharan
The fix in commit 028e045da93b7c1c26417e80e4b4e388b86a713d was incorrect as it can cause the right edge of the window to shrink when we announce a zero window due to receive buffer being full as its done before the check for seeing if the window is being shrunk because of the selected window. Further the window was calculated purely on available space but in cases where we are getting full sized segments it makes more sense to use the actual bytes being held. This CL changes to use the lower of the total available space vs the available space in the maximal window we could advertise minus the actual payload bytes being held. This change also cleans up the code so that the window selection logic is not duplicated between getSendParams() and windowCrossedACKThresholdLocked. PiperOrigin-RevId: 336404827
2020-10-09RACK: Detect packet reordering.Nayana Bidari
RACK detects packet reordering by checking if the sender received ACK for the packet which has the sequence number less than the already acknowledged packets. PiperOrigin-RevId: 336397526
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
2020-10-05Fix IPv4 ICMP echo handler to copy optionsJulian Elischer
The IPv4 RFCs are specific (though obtuse) that an echo response packet needs to contain all the options from the echo request, much as if it been routed back to the sender, though apparently with a new TTL. They suggest copying the incoming packet header to achieve this so that is what this patch does. PiperOrigin-RevId: 335559176
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
2020-10-02Update minimum RTT for RACK.Nayana Bidari
We are currently tracking the minimum RTT for RACK as smoothed RTT. As per RFC minimum RTT can be a global minimum of all RTTs or filtered value of recent RTT measurements. In this cl minimum RTT is updated to global minimum of all RTTs for the connection. PiperOrigin-RevId: 335061518
2020-09-30ip6tables: redirect supportKevin Krakauer
Adds support for the IPv6-compatible redirect target. Redirection is a limited form of DNAT, where the destination is always the localhost. Updates #3549. PiperOrigin-RevId: 334698344
2020-09-29Don't allow broadcast/multicast source addressGhanan Gowripalan
As per relevant IP RFCS (see code comments), broadcast (for IPv4) and multicast addresses are not allowed. Currently checks for these are done at the transport layer, but since it is explicitly forbidden at the IP layers, check for them there. This change also removes the UDP.InvalidSourceAddress stat since there is no longer a need for it. Test: ip_test.TestSourceAddressValidation PiperOrigin-RevId: 334490971
2020-09-29Discard IP fragments as soon as it expiresToshi Kikuchi
Currently expired IP fragments are discarded only if another fragment for the same IP datagram is received after timeout or the total size of the fragment queue exceeded a predefined value. Test: fragmentation.TestReassemblingTimeout Fixes #3960 PiperOrigin-RevId: 334423710
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
2020-09-28Fix 1 zero window advertisement bug and a TCP test flake.Bhasker Hariharan
In TestReceiveBufferAutoTuning we now send a keep-alive packet to measure the current window rather than a 1 byte segment as the returned window value in the latter case is reduced due to the 1 byte segment now being held in the receive buffer and can cause the test to flake if the segment overheads were to change. In getSendParams in rcv.go we were advertising a non-zero window even if available window space was zero after we received the previous segment. In such a case newWnd and curWnd will be the same and we end up advertising a tiny but non-zero window and this can cause the next segment to be dropped. PiperOrigin-RevId: 334314070
2020-09-28Fix lingering of TCP socket in the initial state.Nayana Bidari
When the socket is set with SO_LINGER and close()'d in the initial state, it should not linger and return immediately. PiperOrigin-RevId: 334263149
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
2020-09-24Remove useless endpoint constructionTamir Duberstein
PiperOrigin-RevId: 333591566
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
2020-09-23Extract ICMP error sender from UDPJulian Elischer
Store transport protocol number on packet buffers for use in ICMP error generation. Updates #2211. PiperOrigin-RevId: 333252762
2020-09-18Enqueue TCP sends arriving in SYN_SENT state.Mithun Iyer
TCP needs to enqueue any send requests arriving when the connection is in SYN_SENT state. The data should be sent out soon after completion of the connection handshake. Fixes #3995 PiperOrigin-RevId: 332482041
2020-09-18Use common parsing utilities when sniffingGhanan Gowripalan
Extract parsing utilities so they can be used by the sniffer. Fixes #3930 PiperOrigin-RevId: 332401880
2020-09-17{Set,Get} SO_LINGER on all endpoints.Nayana Bidari
SO_LINGER is a socket level option and should be stored on all endpoints even though it is used to linger only for TCP endpoints. PiperOrigin-RevId: 332369252
2020-09-16Automated rollback of changelist 329526153Nayana Bidari
PiperOrigin-RevId: 332097286
2020-09-16Receive broadcast packets on interested endpointsGhanan Gowripalan
When a broadcast packet is received by the stack, the packet should be delivered to each endpoint that may be interested in the packet. This includes all any address and specified broadcast address listeners. Test: integration_test.TestReuseAddrAndBroadcast PiperOrigin-RevId: 332060652
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
2020-09-14Store multicast memberships in a setTamir Duberstein
This is simpler and more performant. PiperOrigin-RevId: 331639978
2020-09-14Test RST handling in TIME_WAIT.Mithun Iyer
gVisor stack ignores RSTs when in TIME_WAIT which is not the default Linux behavior. Add a packetimpact test to test the same. Also update code comments to reflect the rationale for the current gVisor behavior. PiperOrigin-RevId: 331629879
2020-09-08Fix data race in tcp.GetSockOpt.Bhasker Hariharan
e.ID can't be read without holding e.mu. GetSockOpt was reading e.ID when looking up OriginalDst without holding e.mu. PiperOrigin-RevId: 330562293