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path: root/pkg/tcpip/stack/iptables.go
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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
2020-09-29iptables: 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
2020-09-18Count packets dropped by iptables in IPStatsKevin Krakauer
PiperOrigin-RevId: 332486383
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
2020-08-28fix panic when calling SO_ORIGINAL_DST without initializing iptablesKevin Krakauer
Reported-by: syzbot+074ec22c42305725b79f@syzkaller.appspotmail.com PiperOrigin-RevId: 328963899
2020-08-27ip6tables: (de)serialize ip6tables structsKevin Krakauer
More implementation+testing to follow. #3549. PiperOrigin-RevId: 328770160
2020-08-20Consistent precondition formattingMichael Pratt
Our "Preconditions:" blocks are very useful to determine the input invariants, but they are bit inconsistent throughout the codebase, which makes them harder to read (particularly cases with 5+ conditions in a single paragraph). I've reformatted all of the cases to fit in simple rules: 1. Cases with a single condition are placed on a single line. 2. Cases with multiple conditions are placed in a bulleted list. This format has been added to the style guide. I've also mentioned "Postconditions:", though those are much less frequently used, and all uses already match this style. PiperOrigin-RevId: 327687465
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
2020-07-31iptables: support SO_ORIGINAL_DSTKevin Krakauer
Envoy (#170) uses this to get the original destination of redirected packets.
2020-07-23iptables: use keyed array literalsKevin Krakauer
PiperOrigin-RevId: 322882426
2020-07-22iptables: don't NAT existing connectionsKevin Krakauer
Fixes a NAT bug that manifested as: - A SYN was sent from gVisor to another host, unaffected by iptables. - The corresponding SYN/ACK was NATted by a PREROUTING REDIRECT rule despite being part of the existing connection. - The socket that sent the SYN never received the SYN/ACK and thus a connection could not be established. We handle this (as Linux does) by tracking all connections, inserting a no-op conntrack rule for new connections with no rules of their own. Needed for istio support (#170).
2020-07-22iptables: replace maps with arraysKevin Krakauer
For iptables users, Check() is a hot path called for every packet one or more times. Let's avoid a bunch of map lookups. PiperOrigin-RevId: 322678699
2020-07-15iptables: remove check for NetworkHeaderKevin Krakauer
This is no longer necessary, as we always set NetworkHeader before calling iptables.Check. PiperOrigin-RevId: 321461978
2020-07-13garbage collect connectionsKevin Krakauer
As in Linux, we must periodically clean up unused connections. PiperOrigin-RevId: 321003353
2020-06-25conntrack refactor, no behavior changesKevin Krakauer
- Split connTrackForPacket into 2 functions instead of switching on flag - Replace hash with struct keys. - Remove prefixes where possible - Remove unused connStatus, timeout - Flatten ConnTrack struct a bit - some intermediate structs had no meaning outside of the context of their parent. - Protect conn.tcb with a mutex - Remove redundant error checking (e.g. when is pkt.NetworkHeader valid) - Clarify that HandlePacket and CreateConnFor are the expected entrypoints for ConnTrack PiperOrigin-RevId: 318407168
2020-06-18iptables: skip iptables if no rules are setKevin Krakauer
Users that never set iptables rules shouldn't incur the iptables performance cost. Suggested by Ian (@iangudger). PiperOrigin-RevId: 317232921
2020-06-18iptables: remove metadata structKevin Krakauer
Metadata was useful for debugging and safety, but enough tests exist that we should see failures when (de)serialization is broken. It made stack initialization more cumbersome and it's also getting in the way of ip6tables. PiperOrigin-RevId: 317210653
2020-06-05Fix copylocks error about copying IPTables.Ting-Yu Wang
IPTables.connections contains a sync.RWMutex. Copying it will trigger copylocks analysis. Tested by manually enabling nogo tests. sync.RWMutex is added to IPTables for the additional race condition discovered. PiperOrigin-RevId: 314817019
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
2020-05-28Enable iptables source filtering (-s/--source)Kevin Krakauer
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
2020-05-01Support for connection tracking of TCP packets.Nayana Bidari
Connection tracking is used to track packets in prerouting and output hooks of iptables. The NAT rules modify the tuples in connections. The connection tracking code modifies the packets by looking at the modified tuples.
2020-05-01Automated rollback of changelist 308674219Kevin Krakauer
PiperOrigin-RevId: 309491861
2020-04-27Automated rollback of changelist 308163542gVisor bot
PiperOrigin-RevId: 308674219
2020-04-23Remove View.First() and View.RemoveFirst()Kevin Krakauer
These methods let users eaily break the VectorisedView abstraction, and allowed netstack to slip into pseudo-enforcement of the "all headers are in the first View" invariant. Removing them and replacing with PullUp(n) breaks this reliance and will make it easier to add iptables support and rework network buffer management. The new View.PullUp(n) method is low cost in the common case, when when all the headers fit in the first View. PiperOrigin-RevId: 308163542
2020-04-21Automated rollback of changelist 307477185gVisor bot
PiperOrigin-RevId: 307598974
2020-04-17Remove View.First() and View.RemoveFirst()Kevin Krakauer
These methods let users eaily break the VectorisedView abstraction, and allowed netstack to slip into pseudo-enforcement of the "all headers are in the first View" invariant. Removing them and replacing with PullUp(n) breaks this reliance and will make it easier to add iptables support and rework network buffer management. The new View.PullUp(n) method is low cost in the common case, when when all the headers fit in the first View.
2020-04-03Refactor software GSO code.Bhasker Hariharan
Software GSO implementation currently has a complicated code path with implicit assumptions that all packets to WritePackets carry same Data and it does this to avoid allocations on the path etc. But this makes it hard to reuse the WritePackets API. This change breaks all such assumptions by introducing a new Vectorised View API ReadToVV which can be used to cleanly split a VV into multiple independent VVs. Further this change also makes packet buffers linkable to form an intrusive list. This allows us to get rid of the array of packet buffers that are passed in the WritePackets API call and replace it with a list of packet buffers. While this code does introduce some more allocations in the benchmarks it doesn't cause any degradation. Updates #231 PiperOrigin-RevId: 304731742
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