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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
2020-10-23Rewrite 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
2020-10-09Automated 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
2020-08-25Use 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
2020-08-13Migrate 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
2020-08-03Plumbing 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
2020-07-15Fix 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
2020-06-03Pass 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
2020-03-24Move tcpip.PacketBuffer and IPTables to stack package.Bhasker Hariharan
This is a precursor to be being able to build an intrusive list of PacketBuffers for use in queuing disciplines being implemented. Updates #2214 PiperOrigin-RevId: 302677662
2020-03-16Enable ARP resolution in TAP devices.Ting-Yu Wang
PiperOrigin-RevId: 301208471
2020-02-21Implement tap/tun device in vfs.Ting-Yu Wang
PiperOrigin-RevId: 296526279
2020-01-27Standardize on tools directory.Adin Scannell
PiperOrigin-RevId: 291745021
2019-11-23Cleanup visibility.Adin Scannell
PiperOrigin-RevId: 282194656
2019-06-13Update canonical repository.Adin Scannell
This can be merged after: https://github.com/google/gvisor-website/pull/77 or https://github.com/google/gvisor-website/pull/78 PiperOrigin-RevId: 253132620
2019-04-29Change copyright notice to "The gVisor Authors"Michael Pratt
Based on the guidelines at https://opensource.google.com/docs/releasing/authors/. 1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./' 2. Manual fixup of "Google Inc" references. 3. Add AUTHORS file. Authors may request to be added to this file. 4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS. Fixes #209 PiperOrigin-RevId: 245823212 Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
2019-01-31Remove license commentsMichael Pratt
Nothing reads them and they can simply get stale. Generated with: $ sed -i "s/licenses(\(.*\)).*/licenses(\1)/" **/BUILD PiperOrigin-RevId: 231818945 Change-Id: Ibc3f9838546b7e94f13f217060d31f4ada9d4bf0
2018-10-23Track paths and provide a rename hook.Adin Scannell
This change also adds extensive testing to the p9 package via mocks. The sanity checks and type checks are moved from the gofer into the core package, where they can be more easily validated. PiperOrigin-RevId: 218296768 Change-Id: I4fc3c326e7bf1e0e140a454cbacbcc6fd617ab55
2018-10-19Use correct company name in copyright headerIan Gudger
PiperOrigin-RevId: 217951017 Change-Id: Ie08bf6987f98467d07457bcf35b5f1ff6e43c035
2018-08-22Allow building on !linuxGoogler
PiperOrigin-RevId: 209819644 Change-Id: I329d054bf8f4999e7db0dcd95b13f7793c65d4e2
2018-07-27stateify: support explicit annotation mode; convert refs and stack packages.Zhaozhong Ni
We have been unnecessarily creating too many savable types implicitly. PiperOrigin-RevId: 206334201 Change-Id: Idc5a3a14bfb7ee125c4f2bb2b1c53164e46f29a8
2018-07-09Switch netstack licenses to Apache 2.0.Nicolas Lacasse
Fixes #27 PiperOrigin-RevId: 203825288 Change-Id: Ie9f3a2b2c1e296b026b024f75c07da1a7e118633
2018-04-28Add mising license headers.Nicolas Lacasse
PiperOrigin-RevId: 194676372 Change-Id: I2e7fce03e70a45f2a872160c33e05f822ae2d866
2018-04-28Check in gVisor.Googler
PiperOrigin-RevId: 194583126 Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463
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