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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
2020-10-08Send unicast probes when link address is knownGhanan Gowripalan
When the neighbor table already has link address for a neighbor but is trying to confirm reachability, it may send unicast probes to the neighbor. PiperOrigin-RevId: 336166711
2020-10-08Change IPv6 reassembly timeout to 60sArthur Sfez
It was originally set to 30s for IPv6 (same as IPv4) but this is not what RFC 8200 prescibes. Linux also defaults to 60s [1]. [1] https://github.com/torvalds/linux/blob/47ec5303d73ea344e84f46660fff693c57641386/include/net/ipv6.h#L456 PiperOrigin-RevId: 336034636
2020-10-06Discard invalid Neighbor SolicitationsPeter Johnston
...per RFC 4861 s7.1.1. PiperOrigin-RevId: 335742851
2020-10-06Add support for IPv6 fragmentationArthur Sfez
Most of the IPv4 fragmentation code was moved in the fragmentation package and it is reused by IPv6 fragmentation. Test: - pkg/tcpip/network/ipv4:ipv4_test - pkg/tcpip/network/ipv6:ipv6_test - pkg/tcpip/network/fragmentation:fragmentation_test Fixes #4389 PiperOrigin-RevId: 335714280
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
2020-09-30Count IP OutgoingPacketErrors in the NetworkEndpoint methodsArthur Sfez
Before this change, OutgoingPacketErrors was incremented in the stack.Route methods. This was going to be a problem once IPv4/IPv6 WritePackets support fragmentation because Route.WritePackets might now know how many packets are left after an error occurs. Test: - pkg/tcpip/network/ipv4:ipv4_test - pkg/tcpip/network/ipv6:ipv6_test PiperOrigin-RevId: 334687983
2020-09-30Use the ICMP error response facilityJulian Elischer
Add code in IPv6 to send ICMP packets while processing extension headers. Add some accounting in processing IPV6 Extension headers which allows us to report meaningful information back in ICMP parameter problem packets. IPv4 also needs to send a message when an unsupported protocol is requested. Add some tests to generate both ipv4 and ipv6 packets with various errors and check the responses. Add some new checkers and cleanup some inconsistencies in the messages in that file. Add new error types for the ICMPv4/6 generators. Fix a bug in the ICMPv4 generator that stopped it from generating "Unknown protocol" messages. Updates #2211 PiperOrigin-RevId: 334661716
2020-09-29Return permanent addresses when NIC is downGhanan Gowripalan
Test: stack_test.TestGetMainNICAddressWhenNICDisabled PiperOrigin-RevId: 334513286
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
2020-09-29iptables: refactor to make targets extendableKevin Krakauer
Like matchers, targets should use a module-like register/lookup system. This replaces the brittle switch statements we had before. The only behavior change is supporing IPT_GET_REVISION_TARGET. This makes it much easier to add IPv6 redirect in the next change. Updates #3549. PiperOrigin-RevId: 334469418
2020-09-29Don't generate link-local IPv6 for loopbackGhanan Gowripalan
Linux doesn't generate a link-local address for the loopback interface. Test: integration_test.TestInitialLoopbackAddresses PiperOrigin-RevId: 334453182
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
2020-09-28Support 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
2020-09-26Remove generic ICMP errorsGhanan Gowripalan
Generic ICMP errors were required because the transport dispatcher was given the responsibility of sending ICMP errors in response to transport packet delivery failures. Instead, the transport dispatcher should let network layer know it failed to deliver a packet (and why) and let the network layer make the decision as to what error to send (if any). Fixes #4068 PiperOrigin-RevId: 333962333
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
2020-09-22Refactor testutil.TestEndpoint and use it instead of limitedEPArthur Sfez
The new testutil.MockLinkEndpoint implementation is not composed by channel.Channel anymore because none of its features were used. PiperOrigin-RevId: 333167753
2020-09-20Merge pull request #3651 from ianlewis:ip-forwardinggVisor bot
PiperOrigin-RevId: 332760843
2020-09-18Count packets dropped by iptables in IPStatsKevin Krakauer
PiperOrigin-RevId: 332486383
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
2020-09-17Test IPv4 WritePackets statsKevin Krakauer
IPv6 tests will be added in another CL along with ip6tables. PiperOrigin-RevId: 332389102
2020-09-17ip6tables: filter table supportKevin Krakauer
`ip6tables -t filter` is now usable. NAT support will come in a future CL. #3549 PiperOrigin-RevId: 332381801
2020-09-15Move reusable IPv4 test code into a testutil module and refactor itArthur Sfez
The refactor aims to simplify the package, by replacing the Go channel with a PacketBuffer slice. This code will be reused by tests for IPv6 fragmentation. PiperOrigin-RevId: 331860411
2020-09-12Cap reassembled IPv6 packets at 65535 octetsToshi Kikuchi
IPv4 can accept 65536-octet reassembled packets. Test: - ipv4_test.TestInvalidFragments - ipv4_test.TestReceiveFragments - ipv6.TestInvalidIPv6Fragments - ipv6.TestReceiveIPv6Fragments Fixes #3770 PiperOrigin-RevId: 331382977
2020-08-28Improve type safety for network protocol optionsGhanan Gowripalan
The existing implementation for NetworkProtocol.{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 network protocol options that may be set or queried which network 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. PiperOrigin-RevId: 328980359
2020-08-25Add option to replace linkAddrCache with neighborCacheSam Balana
This change adds an option to replace the current implementation of ARP through linkAddrCache, with an implementation of NUD through neighborCache. Switching to using NUD for both ARP and NDP is beneficial for the reasons described by RFC 4861 Section 3.1: "[Using NUD] significantly improves the robustness of packet delivery in the presence of failing routers, partially failing or partitioned links, or nodes that change their link-layer addresses. For instance, mobile nodes can move off-link without losing any connectivity due to stale ARP caches." "Unlike ARP, Neighbor Unreachability Detection detects half-link failures and avoids sending traffic to neighbors with which two-way connectivity is absent." Along with these changes exposes the API for querying and operating the neighbor cache. Operations include: - Create a static entry - List all entries - Delete all entries - Remove an entry by address This also exposes the API to change 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][1] for the list of constants. Finally, an API for subscribing to NUD state changes is exposed through NUDDispatcher. See [RFC 4861 Appendix C][3] for the list of edges. Tests: pkg/tcpip/network/arp:arp_test + TestDirectRequest pkg/tcpip/network/ipv6:ipv6_test + TestLinkResolution + TestNDPValidation + TestNeighorAdvertisementWithTargetLinkLayerOption + TestNeighorSolicitationResponse + TestNeighorSolicitationWithSourceLinkLayerOption + TestRouterAdvertValidation pkg/tcpip/stack:stack_test + TestCacheWaker + TestForwardingWithFakeResolver + TestForwardingWithFakeResolverManyPackets + TestForwardingWithFakeResolverManyResolutions + TestForwardingWithFakeResolverPartialTimeout + TestForwardingWithFakeResolverTwoPackets + TestIPv6SourceAddressSelectionScopeAndSameAddress [1]: https://tools.ietf.org/html/rfc4861#section-10 [2]: https://tools.ietf.org/html/rfc4861#appendix-C Fixes #1889 Fixes #1894 Fixes #1895 Fixes #1947 Fixes #1948 Fixes #1949 Fixes #1950 PiperOrigin-RevId: 328365034
2020-08-20Only use the NextHeader value of the first IPv6 fragment extension header.Arthur Sfez
As per RFC 8200 Section 4.5: The Next Header field of the last header of the Per-Fragment headers is obtained from the Next Header field of the first fragment's Fragment header. Test: - pkg/tcpip/network/ipv6:ipv6_test - pkg/tcpip/network/ipv4:ipv4_test - pkg/tcpip/network/fragmentation:fragmentation_test Updates #2197 PiperOrigin-RevId: 327671635
2020-08-17Add a unit test for out of order IP reassemblyArthur Sfez
PiperOrigin-RevId: 327042869
2020-08-14Use a single NetworkEndpoint per NIC per protocolGhanan Gowripalan
The NetworkEndpoint does not need to be created for each address. Most of the work the NetworkEndpoint does is address agnostic. PiperOrigin-RevId: 326759605
2020-08-14Give the ICMP Code its own typeJulian Elischer
This is a preparatory commit for a larger commit working on ICMP generation in error cases. This is removal of technical debt and cleanup in the gvisor code as part of gvisor issue 2211. Updates #2211. PiperOrigin-RevId: 326615389
2020-08-13Migrate to PacketHeader API for PacketBuffer.Ting-Yu Wang
Formerly, when a packet is constructed or parsed, all headers are set by the client code. This almost always involved prepending to pk.Header buffer or trimming pk.Data portion. This is known to prone to bugs, due to the complexity and number of the invariants assumed across netstack to maintain. In the new PacketHeader API, client will call Push()/Consume() method to construct/parse an outgoing/incoming packet. All invariants, such as slicing and trimming, are maintained by the API itself. NewPacketBuffer() is introduced to create new PacketBuffer. Zero value is no longer valid. PacketBuffer now assumes the packet is a concatenation of following portions: * LinkHeader * NetworkHeader * TransportHeader * Data Any of them could be empty, or zero-length. PiperOrigin-RevId: 326507688
2020-08-10Set the NetworkProtocolNumber of all PacketBuffers.Kevin Krakauer
NetworkEndpoints set the number on outgoing packets in Write() and NetworkProtocols set them on incoming packets in Parse(). Needed for #3549. PiperOrigin-RevId: 325938745
2020-08-08Use unicast source for ICMP echo repliesGhanan Gowripalan
Packets MUST NOT use a non-unicast source address for ICMP Echo Replies. Test: integration_test.TestPingMulticastBroadcast PiperOrigin-RevId: 325634380
2020-08-04Use 1 fragmentation component per IP stackGhanan Gowripalan
This will help manage memory consumption by IP reassembly when receiving IP fragments on multiple network endpoints. Previously, each endpoint would cap memory consumption at 4MB, but with this change, each IP stack will cap memory consumption at 4MB. No behaviour changes. PiperOrigin-RevId: 324913904
2020-07-31Support fragments from different sourcesGhanan Gowripalan
Prevent fragments with different source-destination pairs from conflicting with each other. Test: - ipv6_test.TestReceiveIPv6Fragments - ipv4_test.TestReceiveIPv6Fragments PiperOrigin-RevId: 324283246
2020-07-30Enforce fragment block size and validate argsGhanan Gowripalan
Allow configuring fragmentation.Fragmentation with a fragment block size which will be enforced when processing fragments. Also validate arguments when processing fragments. Test: - fragmentation.TestErrors - ipv6_test.TestReceiveIPv6Fragments - ipv4_test.TestReceiveIPv6Fragments PiperOrigin-RevId: 324081521
2020-07-27Add ability to send unicast ARP requests and Neighbor SolicitationsSam Balana
The previous implementation of LinkAddressRequest only supported sending broadcast ARP requests and multicast Neighbor Solicitations. The ability to send these packets as unicast is required for Neighbor Unreachability Detection. Tests: pkg/tcpip/network/arp:arp_test - TestLinkAddressRequest pkg/tcpip/network/ipv6:ipv6_test - TestLinkAddressRequest Updates #1889 Updates #1894 Updates #1895 Updates #1947 Updates #1948 Updates #1949 Updates #1950 PiperOrigin-RevId: 323451569
2020-07-22make connect(2) fail when dest is unreachableKevin Krakauer
Previously, ICMP destination unreachable datagrams were ignored by TCP endpoints. This caused connect to hang when an intermediate router couldn't find a route to the host. This manifested as a Kokoro error when Docker IPv6 was enabled. The Ruby image test would try to install the sinatra gem and hang indefinitely attempting to use an IPv6 address. Fixes #3079.
2020-07-22Support for receiving outbound packets in AF_PACKET.Bhasker Hariharan
Updates #173 PiperOrigin-RevId: 322665518
2020-07-16Add ethernet broadcast address constantGhanan Gowripalan
PiperOrigin-RevId: 321620517
2020-07-15Fix minor bugs in a couple of interface IOCTLs.Bhasker Hariharan
gVisor incorrectly returns the wrong ARP type for SIOGIFHWADDR. This breaks tcpdump as it tries to interpret the packets incorrectly. Similarly, SIOCETHTOOL is used by tcpdump to query interface properties which fails with an EINVAL since we don't implement it. For now change it to return EOPNOTSUPP to indicate that we don't support the query rather than return EINVAL. NOTE: ARPHRD types for link endpoints are distinct from NIC capabilities and NIC flags. In Linux all 3 exist eg. ARPHRD types are stored in dev->type field while NIC capabilities are more like the device features which can be queried using SIOCETHTOOL but not modified and NIC Flags are fields that can be modified from user space. eg. NIC status (UP/DOWN/MULTICAST/BROADCAST) etc. Updates #2746 PiperOrigin-RevId: 321436525
2020-07-13Merge pull request #2672 from amscanne:shim-integratedgVisor bot
PiperOrigin-RevId: 321053634
2020-07-07Set IPv4 ID on all non-atomic datagramsTony Gong
RFC 6864 imposes various restrictions on the uniqueness of the IPv4 Identification field for non-atomic datagrams, defined as an IP datagram that either can be fragmented (DF=0) or is already a fragment (MF=1 or positive fragment offset). In order to be compliant, the ID field is assigned for all non-atomic datagrams. Add a TCP unit test that induces retransmissions and checks that the IPv4 ID field is unique every time. Add basic handling of the IP_MTU_DISCOVER socket option so that the option can be used to disable PMTU discovery, effectively setting DF=0. Attempting to set the sockopt to anything other than disabled will fail because PMTU discovery is currently not implemented, and the default behavior matches that of disabled. PiperOrigin-RevId: 320081842
2020-06-07netstack: parse incoming packet headers up-frontKevin Krakauer
Netstack has traditionally parsed headers on-demand as a packet moves up the stack. This is conceptually simple and convenient, but incompatible with iptables, where headers can be inspected and mangled before even a routing decision is made. This changes header parsing to happen early in the incoming packet path, as soon as the NIC gets the packet from a link endpoint. Even if an invalid packet is found (e.g. a TCP header of insufficient length), the packet is passed up the stack for proper stats bookkeeping. PiperOrigin-RevId: 315179302
2020-06-05iptables: loopback traffic skips prerouting chainKevin Krakauer
Loopback traffic is not affected by rules in the PREROUTING chain. This change is also necessary for istio's envoy to talk to other components in the same pod.
2020-06-03Pass PacketBuffer as pointer.Ting-Yu Wang
Historically we've been passing PacketBuffer by shallow copying through out the stack. Right now, this is only correct as the caller would not use PacketBuffer after passing into the next layer in netstack. With new buffer management effort in gVisor/netstack, PacketBuffer will own a Buffer (to be added). Internally, both PacketBuffer and Buffer may have pointers and shallow copying shouldn't be used. Updates #2404. PiperOrigin-RevId: 314610879
2020-05-08iptables - filter packets using outgoing interface.gVisor bot
Enables commands with -o (--out-interface) for iptables rules. $ iptables -A OUTPUT -o eth0 -j ACCEPT PiperOrigin-RevId: 310642286
2020-05-06Add basic incoming ipv4 fragment testsKevin Krakauer
Based on ipv6's TestReceiveIPv6Fragments.