Network endpoints that wish to check addresses on another NIC-local
network endpoint may now do so through the NetworkInterface.
This fixes a lock ordering issue between NIC removal and link
resolution. Before this change:
NIC Removal takes the stack lock, neighbor cache lock then neighbor
entries' locks.
When performing IPv4 link resolution, we take the entry lock then ARP
would try check IPv4 local addresses through the stack which tries to
obtain the stack's lock.
Now that ARP can check IPv4 addreses through the NIC, we avoid the lock
ordering issue, while also removing the need for stack to lookup the
NIC.
PiperOrigin-RevId: 356034245
After IPTables checks a batch of packets, we can write packets that are
not dropped or locally destined as a batch instead of individually.
This previously caused a bug since WritePacket* functions expect to take
ownership of passed PacketBuffer{List}. WritePackets assumed the list of
PacketBuffers will not be invalidated when calling WritePacket for each
PacketBuffer in the list, but this is not true. WritePacket may add the
passed PacketBuffer into a different list which would modify the
PacketBuffer in such a way that it no longer points to the next
PacketBuffer to write.
Example: Given a PB list of
PB_a -> PB_b -> PB_c
WritePackets may be iterating over the list and calling WritePacket for
each PB. When WritePacket takes PB_a, it may add it to a new list which
would update pointers such that PB_a no longer points to PB_b.
Test: integration_test.TestIPTableWritePackets
PiperOrigin-RevId: 355969560
Make it clear that failing to parse a looped back is not a packet
sending error but a malformed received packet error.
FindNetworkEndpoint returns nil when no network endpoint is found
instead of an error.
PiperOrigin-RevId: 355954946
...to remove the need for the transport layer to deduce the type of
error it received.
Rename HandleControlPacket to HandleError as HandleControlPacket only
handles errors.
tcpip.SockError now holds a tcpip.SockErrorCause interface that
different errors can implement.
PiperOrigin-RevId: 354994306
The network endpoint should not need to have logic to handle different
kinds of neighbor tables. Network endpoints can let the NIC know about
differnt neighbor discovery messages and let the NIC decide which table
to update.
This allows us to remove the LinkAddressCache interface.
PiperOrigin-RevId: 354812584
The RFC for icmpv6 specifies that an errant packet should be included
in the returned ICMP packet, and that it should include up to the amount
needed to fill the minimum MTU (1280 bytes) if possible. The current code
included the Link header in that calculation but the RFC is referring
to the IP MTU not the link MTU. Some conformance tests check this and
report an error agains the stack for this.
The full header length shoudl however continue to be used when allocating
header space.
Make the same change for IPv4 for consistency.
Add a test for icmp payload sizing.
Test that the included data in an ICMP error packet conforms to the
requirements of RFC 972, RFC 4443 section 2.4 and RFC 1812 Section 4.3.2.3.
Fixes#5311
PiperOrigin-RevId: 353790203
The ARP stat NetworkUnreachable was removed, and was replaced by
InterfaceHasNoLocalAddress. No stats are recorded when dealing with an
missing endpoint (ErrNotConnected) (because if there is no endpoint,
there is no valid per-endpoint stats).
PiperOrigin-RevId: 353759462
It previously returned an error but it could only be UnknownNICID. It now
returns a boolean to indicate whether the nic exists or not.
PiperOrigin-RevId: 353337489
We have support for the output interface name, but not for the input
interface name.
This change adds the support for the input interface name, and adds the
test cases for it.
Fixes#5300
PiperOrigin-RevId: 353179389
The error messages are not needed or used as these are not processing errors
so much as errors to be reported back to the packet sender. Implicitly
describe whether each error should generate ICMP packets or not. Most do
but there are a couple that do not.
Slightly alter some test expectations for Linux compatibility and add a
couple more. Improve Linux compatibility on error packet returns. Some
cosmetic changes to tests to match the upcoming packet impact version
of the same tests.
PiperOrigin-RevId: 352889785
To facilitate the debugging of multi-homed setup, track Network
protocols statistics for each endpoint. Note that the original
stack-wide stats still exist.
A new type of statistic counter is introduced, which track two
versions of a stat at the same time. This lets a network endpoint
increment both the local stat and the stack-wide stat at the same
time.
Fixes#4605
PiperOrigin-RevId: 352663276
IPv4 previously accepts the packet, while IPv6 panics. Neither is the behavior
in Linux.
splice() in Linux has different behavior than in gVisor. This change documents
it in the SpliceTooLong test.
Reported-by: syzbot+b550e78e5c24d1d521f2@syzkaller.appspotmail.com
PiperOrigin-RevId: 352091286
Link address resolution is performed at the link layer (if required) so
we can defer it from the transport layer. When link resolution is
required, packets will be queued and sent once link resolution
completes. If link resolution fails, the transport layer will receive a
control message indicating that the stack failed to route the packet.
tcpip.Endpoint.Write no longer returns a channel now that writes do not
wait for link resolution at the transport layer.
tcpip.ErrNoLinkAddress is no longer used so it is removed.
Removed calls to stack.Route.ResolveWith from the transport layer so
that link resolution is performed when a route is created in response
to an incoming packet (e.g. to complete TCP handshakes or send a RST).
Tests:
- integration_test.TestForwarding
- integration_test.TestTCPLinkResolutionFailure
Fixes#4458
RELNOTES: n/a
PiperOrigin-RevId: 351684158
Read now takes a destination io.Writer, count, options. Keeping the method name
Read, in contrast to the Write method.
This enables:
* direct transfer of views under VV
* zero copy
It also eliminates the need for sentry to keep a slice of view because
userspace had requested a read that is smaller than the view returned, removing
the complexity there.
Read/Peek/ReadPacket are now consolidated together and some duplicate code is
removed.
PiperOrigin-RevId: 350636322
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
This change also considers interfaces and network endpoints enabled up
up to the point all work to disable them are complete. This was needed
so that protocols can perform shutdown work while being disabled (e.g.
sending a packet which requires the endpoint to be enabled to obtain a
source address).
Bug #4682, #4861Fixes#4888
Startblock:
has LGTM from peterjohnston
and then
add reviewer brunodalbo
PiperOrigin-RevId: 346869702
The loopback interface will never have any neighbouring nodes so
advertising its interest in multicast groups is unnecessary.
Bug #4682, #4861
Startblock:
has LGTM from asfez
and then
add reviewer tamird
PiperOrigin-RevId: 346587604
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
This change lets us split the v4 stats from the v6 stats, which will be
useful when adding stats for each network endpoint.
PiperOrigin-RevId: 345322615
Before this change, the join count and the state for IGMP/MLD was held
across different types which required multiple locks to be held when
accessing a multicast group's state.
Bug #4682, #4861Fixes#4916
PiperOrigin-RevId: 345019091
...as defined by RFC 2710. Querier (router)-side MLDv1 is not yet
supported.
The core state machine is shared with IGMPv2.
This is guarded behind a flag (ipv6.Options.MLDEnabled).
Tests: ip_test.TestMGP*
Bug #4861
PiperOrigin-RevId: 344344095
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
The IGMPv2 core state machine can be shared with MLDv1 since they are
almost identical, ignoring specific addresses, constants and packets.
Bug #4682, #4861
PiperOrigin-RevId: 344102615
Added headers, stats, checksum parsing capabilities from RFC 2236 describing
IGMPv2.
IGMPv2 state machine is implemented for each condition, sending and receiving
IGMP Membership Reports and Leave Group messages with backwards compatibility
with IGMPv1 routers.
Test:
* Implemented igmp header parser and checksum calculator in header/igmp_test.go
* ipv4/igmp_test.go tests incoming and outgoing IGMP messages and pathways.
* Added unit test coverage for IGMPv2 RFC behavior + IGMPv1 backwards
compatibility in ipv4/igmp_test.go.
Fixes#4682
PiperOrigin-RevId: 343408809
Group addressable endpoints can simply check if it has joined the
multicast group without maintaining address endpoints. This also
helps remove the dependency on AddressableEndpoint from
GroupAddressableEndpoint.
Now that group addresses are not tracked with address endpoints, we can
avoid accidentally obtaining a route with a multicast local address.
PiperOrigin-RevId: 343336912
- 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
- Pass a PacketBuffer directly instead of releaseCB
- No longer pass a VectorisedView, which is included in the PacketBuffer
- Make it an error if data size is not equal to (last - first + 1)
- Set the callback for the reassembly timeout on NewFragmentation
PiperOrigin-RevId: 342702432
If the packet must no longer be forwarded because its TTL/Hop Limit
reaches 0, send an ICMP Time Exceeded error to the source.
Required as per relevant RFCs. See comments in code for RFC references.
Fixes#1085
Tests:
- ipv4_test.TestForwarding
- ipv6.TestForwarding
PiperOrigin-RevId: 342323610
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
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
This change adds a Subnet() method to AddressableEndpoint so that we
can avoid repeated calls to AddressableEndpoint.AddressWithPrefix().Subnet().
Updates #231
PiperOrigin-RevId: 340969877
* 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 #4688Fixes#3906
PiperOrigin-RevId: 340943442
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
Ghanan Gowripalan
Ting-Yu Wang
Tamir Duberstein
Julian Elischer
Arthur Sfez
Toshi Kikuchi
Peter Johnston
Zeling Feng
Bruno Dal Bo
Ryan Heacock
Bhasker Hariharan
Kevin Krakauer