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2021-06-09Avoid fanout group collisions with best effortKevin Krakauer
Running multiple instances of netstack in the same network namespace can cause collisions when enabling packet fanout for fdbased endpoints. The only bulletproof fix is to run in different network namespaces, but by using `getpid()` instead of 0 as the fanout ID starting point we can avoid collisions in the common case, particularly when testing/experimenting. Addresses #6124
2021-05-22Remove detritusTamir Duberstein
- Unused constants - Unused functions - Unused arguments - Unkeyed literals - Unnecessary conversions PiperOrigin-RevId: 375253464
2021-05-03Convey GSO capabilities through GSOEndpointGhanan Gowripalan
...as all GSO capable endpoints must implement GSOEndpoint. PiperOrigin-RevId: 371804175
2021-04-27Remove uses of the binary package from networking code.Rahat Mahmood
Co-Author: ayushranjan PiperOrigin-RevId: 370785009
2021-04-21Only carry GSO options in the packet bufferGhanan Gowripalan
With this change, GSO options no longer needs to be passed around as a function argument in the write path. This change is done in preparation for a later change that defers segmentation, and may change GSO options for a packet as it flows down the stack. Updates #170. PiperOrigin-RevId: 369774872
2021-03-24Add POLLRDNORM/POLLWRNORM support.Bhasker Hariharan
On Linux these are meant to be equivalent to POLLIN/POLLOUT. Rather than hack these on in sys_poll etc it felt cleaner to just cleanup the call sites to notify for both events. This is what linux does as well. Fixes #5544 PiperOrigin-RevId: 364859977
2021-03-24Fix data race in fdbased when accessing fanoutID.Bhasker Hariharan
PiperOrigin-RevId: 364859173
2021-03-15Make netstack (//pkg/tcpip) buildable for 32 bitKevin Krakauer
Doing so involved breaking dependencies between //pkg/tcpip and the rest of gVisor, which are discouraged anyways. Tested on the Go branch via: gvisor.dev/gvisor/pkg/tcpip/... Addresses #1446. PiperOrigin-RevId: 363081778
2021-03-09Give TCP flags a dedicated typeZeling Feng
- Implement Stringer for it so that we can improve error messages. - Use TCPFlags through the code base. There used to be a mixed usage of byte, uint8 and int as TCP flags. PiperOrigin-RevId: 361940150
2021-03-03Make dedicated methods for data operations in PacketBufferTing-Yu Wang
One of the preparation to decouple underlying buffer implementation. There are still some methods that tie to VectorisedView, and they will be changed gradually in later CLs. This CL also introduce a new ICMPv6ChecksumParams to replace long list of parameters when calling ICMPv6Checksum, aiming to be more descriptive. PiperOrigin-RevId: 360778149
2021-03-03[op] Replace syscall package usage with golang.org/x/sys/unix in pkg/.Ayush Ranjan
The syscall package has been deprecated in favor of golang.org/x/sys. Note that syscall is still used in the following places: - pkg/sentry/socket/hostinet/stack.go: some netlink related functionalities are not yet available in golang.org/x/sys. - syscall.Stat_t is still used in some places because os.FileInfo.Sys() still returns it and not unix.Stat_t. Updates #214 PiperOrigin-RevId: 360701387
2021-02-24Move //pkg/gate.Gate to //pkg/sync.Jamie Liu
- Use atomic add rather than CAS in every Gate method, which is slightly faster in most cases. - Implement Close wakeup using gopark/goready to avoid channel allocation. New benchmarks: name old time/op new time/op delta GateEnterLeave-12 16.7ns ± 1% 10.3ns ± 1% -38.44% (p=0.000 n=9+8) GateClose-12 50.2ns ± 8% 42.4ns ± 6% -15.44% (p=0.000 n=10+10) GateEnterLeaveAsyncClose-12 972ns ± 2% 640ns ± 7% -34.15% (p=0.000 n=9+10) PiperOrigin-RevId: 359336344
2021-02-18Bump build constraints to Go 1.18Michael Pratt
These are bumped to allow early testing of Go 1.17. Use will be audited closer to the 1.17 release. PiperOrigin-RevId: 358278615
2021-02-06Synchronously send packets over pipe link endpointGhanan Gowripalan
Before this change, packets were delivered asynchronously to the remote end of a pipe. This was to avoid a deadlock during link resolution where the stack would attempt to double-lock a mutex (see removed comments in the parent commit for details). As of https://github.com/google/gvisor/commit/4943347137, we do not hold locks while sending link resolution probes so the deadlock will no longer occur. PiperOrigin-RevId: 356066224
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
2021-01-25fdbased: Dedup code related to iovec readingTing-Yu Wang
PiperOrigin-RevId: 353755271
2021-01-21Queue packets in WritePackets when resolving link addressGhanan Gowripalan
Test: integration_test.TestWritePacketsLinkResolution Fixes #4458. PiperOrigin-RevId: 353108826
2021-01-21Populate EgressRoute, GSO, Netproto in NICGhanan Gowripalan
fdbased and qdisc layers expect these fields to already be populated before being reached. PiperOrigin-RevId: 353099492
2021-01-15Support GetLinkAddress with neighborCacheGhanan Gowripalan
Test: integration_test.TestGetLinkAddress PiperOrigin-RevId: 352119404
2021-01-15Only pass stack.Route's fields to LinkEndpointsGhanan Gowripalan
stack.Route is used to send network packets and resolve link addresses. A LinkEndpoint does not need to do either of these and only needs the route's fields at the time of the packet write request. Since LinkEndpoints only need the route's fields when writing packets, pass a stack.RouteInfo instead. PiperOrigin-RevId: 352108405
2021-01-15Populate EgressRoute, GSO, Netproto for batch writesGhanan Gowripalan
We loop over the list of packets anyways so setting these aren't expensive. Now that they are populated only by the link endpoint that uses them, TCP does not need to. PiperOrigin-RevId: 352090853
2021-01-13Switch uses of os.Getenv that check for empty string to os.LookupEnv.Dean Deng
Whether the variable was found is already returned by syscall.Getenv. os.Getenv drops this value while os.Lookupenv passes it along. PiperOrigin-RevId: 351674032
2021-01-12Fix simple mistakes identified by goreportcard.Adin Scannell
These are primarily simplification and lint mistakes. However, minor fixes are also included and tests added where appropriate. PiperOrigin-RevId: 351425971
2021-01-06Do not filter frames in ethernet link endpointGhanan Gowripalan
Ethernet frames are usually filtered at the hardware-level so there is no need to filter the frames in software. For test purposes, a new link endpoint was introduced to filter frames based on their destination. PiperOrigin-RevId: 350422941
2020-12-22Correctly log sniffed ARP packetsTamir Duberstein
This condition was inverted in 360006d. PiperOrigin-RevId: 348679088
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
2020-12-10Disable host reassembly for fragments.Bhasker Hariharan
fdbased endpoint was enabling fragment reassembly on the host AF_PACKET socket to ensure that fragments are delivered inorder to the right dispatcher. But this prevents fragments from being delivered to gvisor at all and makes testing of gvisor's fragment reassembly code impossible. The potential impact from this is minimal since IP Fragmentation is not really that prevelant and in cases where we do get fragments we may deliver the fragment out of order to the TCP layer as multiple network dispatchers may process the fragments and deliver a reassembled fragment after the next packet has been delivered to the TCP endpoint. While not desirable I believe the impact from this is minimal due to low prevalence of fragmentation. Also removed PktType and Hatype fields when binding the socket as these are not used when binding. Its just confusing to have them specified. See: https://man7.org/linux/man-pages/man7/packet.7.html "Fields used for binding are sll_family (should be AF_PACKET), sll_protocol, and sll_ifindex." Fixes #5055 PiperOrigin-RevId: 346919439
2020-12-03Make `stack.Route` thread safePeter Johnston
Currently we rely on the user to take the lock on the endpoint that owns the route, in order to modify it safely. We can instead move `Route.RemoteLinkAddress` under `Route`'s mutex, and allow non-locking and thread-safe access to other fields of `Route`. PiperOrigin-RevId: 345461586
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
2020-11-18Introduce 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
2020-11-17Add per-sniffer instance log prefixBruno Dal Bo
A prefix associated with a sniffer instance can help debug situations where more than one NIC (i.e. more than one sniffer) exists. PiperOrigin-RevId: 342950027
2020-11-16Remove ARP address workaroundGhanan Gowripalan
- Make AddressableEndpoint optional for NetworkEndpoint. Not all NetworkEndpoints need to support addressing (e.g. ARP), so AddressableEndpoint should only be implemented for protocols that support addressing such as IPv4 and IPv6. With this change, tcpip.ErrNotSupported will be returned by the stack when attempting to modify addresses on a network endpoint that does not support addressing. Now that packets are fully handled at the network layer, and (with this change) addresses are optional for network endpoints, we no longer need the workaround for ARP where a fake ARP address was added to each NIC that performs ARP so that packets would be delivered to the ARP layer. PiperOrigin-RevId: 342722547
2020-11-09Initialize references with a value of 1.Dean Deng
This lets us avoid treating a value of 0 as one reference. All references using the refsvfs2 template must call InitRefs() before the reference is incremented/decremented, or else a panic will occur. Therefore, it should be pretty easy to identify missing InitRef calls during testing. Updates #1486. PiperOrigin-RevId: 341411151
2020-11-06Trim link headers from buffer clone when sniffingGhanan Gowripalan
PiperOrigin-RevId: 341135083
2020-10-23Rewrite reference leak checker without finalizers.Dean Deng
Our current reference leak checker uses finalizers to verify whether an object has reached zero references before it is garbage collected. There are multiple problems with this mechanism, so a rewrite is in order. With finalizers, there is no way to guarantee that a finalizer will run before the program exits. When an unreachable object with a finalizer is garbage collected, its finalizer will be added to a queue and run asynchronously. The best we can do is run garbage collection upon sandbox exit to make sure that all finalizers are enqueued. Furthermore, if there is a chain of finalized objects, e.g. A points to B points to C, garbage collection needs to run multiple times before all of the finalizers are enqueued. The first GC run will register the finalizer for A but not free it. It takes another GC run to free A, at which point B's finalizer can be registered. As a result, we need to run GC as many times as the length of the longest such chain to have a somewhat reliable leak checker. Finally, a cyclical chain of structs pointing to one another will never be garbage collected if a finalizer is set. This is a well-known issue with Go finalizers (https://github.com/golang/go/issues/7358). Using leak checking on filesystem objects that produce cycles will not work and even result in memory leaks. The new leak checker stores reference counted objects in a global map when leak check is enabled and removes them once they are destroyed. At sandbox exit, any remaining objects in the map are considered as leaked. This provides a deterministic way of detecting leaks without relying on the complexities of finalizers and garbage collection. This approach has several benefits over the former, including: - Always detects leaks of objects that should be destroyed very close to sandbox exit. The old checker very rarely detected these leaks, because it relied on garbage collection to be run in a short window of time. - Panics if we forgot to enable leak check on a ref-counted object (we will try to remove it from the map when it is destroyed, but it will never have been added). - Can store extra logging information in the map values without adding to the size of the ref count struct itself. With the size of just an int64, the ref count object remains compact, meaning frequent operations like IncRef/DecRef are more cache-efficient. - Can aggregate leak results in a single report after the sandbox exits. Instead of having warnings littered in the log, which were non-deterministically triggered by garbage collection, we can print all warning messages at once. Note that this could also be a limitation--the sandbox must exit properly for leaks to be detected. Some basic benchmarking indicates that this change does not significantly affect performance when leak checking is enabled, which is understandable since registering/unregistering is only done once for each filesystem object. Updates #1486. PiperOrigin-RevId: 338685972
2020-10-20Fix nogo test in //pkg/tcpip/...Ting-Yu Wang
PiperOrigin-RevId: 338168977
2020-10-16Don't include link header when forwarding packetsGhanan Gowripalan
Before this change, if a link header was included in an incoming packet that is forwarded, the packet that gets sent out will take the original packet and add a link header to it while keeping the old link header. This would make the sent packet look like: OUTGOING LINK HDR | INCOMING LINK HDR | NETWORK HDR | ... Obviously this is incorrect as we should drop the incoming link header and only include the outgoing link header. This change fixes this bug. Test: integration_test.TestForwarding PiperOrigin-RevId: 337571447
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
2020-09-18Use common parsing utilities when sniffingGhanan Gowripalan
Extract parsing utilities so they can be used by the sniffer. Fixes #3930 PiperOrigin-RevId: 332401880
2020-09-16Gracefully translate unknown errno.Ting-Yu Wang
Neither POSIX.1 nor Linux defines an upperbound for errno. PiperOrigin-RevId: 332085017
2020-08-25Use new reference count utility throughout gvisor.Dean Deng
This uses the refs_vfs2 template in vfs2 as well as objects common to vfs1 and vfs2. Note that vfs1-only refcounts are not replaced, since vfs1 will be deleted soon anyway. The following structs now use the new tool, with leak check enabled: devpts:rootInode fuse:inode kernfs:Dentry kernfs:dir kernfs:readonlyDir kernfs:StaticDirectory proc:fdDirInode proc:fdInfoDirInode proc:subtasksInode proc:taskInode proc:tasksInode vfs:FileDescription vfs:MountNamespace vfs:Filesystem sys:dir kernel:FSContext kernel:ProcessGroup kernel:Session shm:Shm mm:aioMappable mm:SpecialMappable transport:queue And the following use the template, but because they currently are not leak checked, a TODO is left instead of enabling leak check in this patch: kernel:FDTable tun:tunEndpoint Updates #1486. PiperOrigin-RevId: 328460377
2020-08-24Bump build constraints to 1.17Michael Pratt
This enables pre-release testing with 1.16. The intention is to replace these with a nogo check before the next release. PiperOrigin-RevId: 328193911
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
2020-08-11Fix-up issue comment.Adin Scannell
PiperOrigin-RevId: 326129258
2020-08-03Plumbing context.Context to DecRef() and Release().Nayana Bidari
context is passed to DecRef() and Release() which is needed for SO_LINGER implementation. PiperOrigin-RevId: 324672584
2020-07-22Support for receiving outbound packets in AF_PACKET.Bhasker Hariharan
Updates #173 PiperOrigin-RevId: 322665518
2020-07-15fdbased: Vectorized write for packet; relax writev syscall filter.Ting-Yu Wang
Now it calls pkt.Data.ToView() when writing the packet. This may require copying when the packet is large, which puts the worse case in an even worse situation. This sent out in a separate preparation change as it requires syscall filter changes. This change will be followed by the change for the adoption of the new PacketHeader API. PiperOrigin-RevId: 321447003
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