This change adds support to send NDP Router Solicitation messages when a NIC
becomes enabled as a host, as per RFC 4861 section 6.3.7.
Note, Router Solicitations will only be sent when the stack has forwarding
disabled.
Tests: Unittests to make sure that the initial Router Solicitations are sent
as configured. The tests also validate the sent Router Solicitations' fields.
PiperOrigin-RevId: 289964095
All inbound segments for connections in ESTABLISHED state are delivered to the
endpoint's queue but for every segment delivered we also queue the endpoint for
processing to a selected processor. This ensures that when there are a large
number of connections in ESTABLISHED state the inbound packets are all handled
by a small number of goroutines and significantly reduces the amount of work the
goscheduler has to perform.
We let connections in other states follow the current path where the
endpoint's goroutine directly handles the segments.
Updates #231
PiperOrigin-RevId: 289728325
* Rename syncutil to sync.
* Add aliases to sync types.
* Replace existing usage of standard library sync package.
This will make it easier to swap out synchronization primitives. For example,
this will allow us to use primitives from github.com/sasha-s/go-deadlock to
check for lock ordering violations.
Updates #1472
PiperOrigin-RevId: 289033387
Inform the Stack's NDPDispatcher when it receives an NDP Router Advertisement
that updates the available configurations via DHCPv6. The Stack makes sure that
its NDPDispatcher isn't informed unless the avaiable configurations via DHCPv6
for a NIC is updated.
Tests: Test that a Stack's NDPDispatcher is informed when it receives an NDP
Router Advertisement that informs it of new configurations available via DHCPv6.
PiperOrigin-RevId: 289001283
Internal tools timeout after 60s during tests that are required to pass before
changes can be submitted. Separate out NDP tests into its own package to help
prevent timeouts when testing.
PiperOrigin-RevId: 288990597
...retrievable later via stack.NICInfo().
Clients of this library can use it to add metadata that should be tracked
alongside a NIC, to avoid having to keep a map[tcpip.NICID]metadata mirroring
stack.Stack's nic map.
PiperOrigin-RevId: 288924900
Add a new CancellableTimer type to encapsulate the work of safely stopping
timers when it fires at the same time some "related work" is being handled. The
term "related work" is some work that needs to be done while having obtained
some common lock (L).
Example: Say we have an invalidation timer that may be extended or cancelled by
some event. Creating a normal timer and simply cancelling may not be sufficient
as the timer may have already fired when the event handler attemps to cancel it.
Even if the timer and event handler obtains L before doing work, once the event
handler releases L, the timer will eventually obtain L and do some unwanted
work.
To prevent the timer from doing unwanted work, it checks if it should early
return instead of doing the normal work after obtaining L. When stopping the
timer callers must have L locked so the timer can be safely informed that it
should early return.
Test: Tests that CancellableTimer fires and resets properly. Test to make sure
the timer fn is not called after being stopped within the lock L.
PiperOrigin-RevId: 288806984
...enabling us to remove the "CreateNamedLoopbackNIC" variant of
CreateNIC and all the plumbing to connect it through to where the value
is read in FindRoute.
PiperOrigin-RevId: 288713093
Support deprecating network endpoints on a NIC. If an endpoint is deprecated, it
should not be used for new connections unless a more preferred endpoint is not
available, or unless the deprecated endpoint was explicitly requested.
Test: Test that deprecated endpoints are only returned when more preferred
endpoints are not available and SLAAC addresses are deprecated after its
preferred lifetime
PiperOrigin-RevId: 288562705
Test: Test that an IPv6 link-local address is not auto-generated for loopback
NICs, even when it is enabled for non-loopback NICS.
PiperOrigin-RevId: 288519591
Pass the NIC-internal name to the NIC name function when generating opaque IIDs
so implementations can use the name that was provided when the NIC was created.
Previously, explicit NICID to NIC name resolution was required from the netstack
integrator.
Tests: Test that the name provided when creating a NIC is passed to the NIC name
function when generating opaque IIDs.
PiperOrigin-RevId: 288395359
Support using opaque interface identifiers when generating IPv6 addresses via
SLAAC when configured to do so.
Note, this change does not handle retries in response to DAD conflicts yet.
That will also come in a later change.
Test: Test that when SLAAC addresses are generated, they use opaque interface
identifiers when configured to do so.
PiperOrigin-RevId: 288078605
Support generating opaque interface identifiers as defined by RFC 7217 for
auto-generated IPv6 link-local addresses. Opaque interface identifiers will also
be used for IPv6 addresses auto-generated via SLAAC in a later change.
Note, this change does not handle retries in response to DAD conflicts yet.
That will also come in a later change.
Tests: Test that when configured to generated opaque IIDs, they are properly
generated as outlined by RFC 7217.
PiperOrigin-RevId: 288035349
Added the ability to get/set the IP_RECVTOS socket option on UDP endpoints. If
enabled, TOS from the incoming Network Header passed as ancillary data in the
ControlMessages.
Test:
* Added unit test to udp_test.go that tests getting/setting as well as
verifying that we receive expected TOS from incoming packet.
* Added a syscall test
PiperOrigin-RevId: 287029703
This change supports clearing all host-only NDP state when NICs become routers.
All discovered routers, discovered on-link prefixes and auto-generated addresses
will be invalidated when becoming a router. This is because normally, routers do
not process Router Advertisements to discover routers or on-link prefixes, and
do not do SLAAC.
Tests: Unittest to make sure that all discovered routers, discovered prefixes
and auto-generated addresses get invalidated when transitioning from a host to
a router.
PiperOrigin-RevId: 286902309
This change removes the requirement that a new routing table be provided when a
router or prefix discovery event happens so that an updated routing table may
be provided to the stack at a later time from the event.
This change is to address the use case where the netstack integrator may need to
obtain a lock before providing updated routes in response to the events above.
As an example, say we have an integrator that performs the below two operations
operations as described:
A. Normal route update:
1. Obtain integrator lock
2. Update routes in the integrator
3. Call Stack.SetRouteTable with the updated routes
3.1. Obtain Stack lock
3.2. Update routes in Stack
3.3. Release Stack lock
4. Release integrator lock
B. NDP event triggered route update:
1. Obtain Stack lock
2. Call event handler
2.1. Obtain integrator lock
2.2. Update routes in the integrator
2.3. Release integrator lock
2.4. Return updated routes to update Stack
3. Update routes in Stack
4. Release Stack lock
A deadlock may occur if a Normal route update was attemped at the same time an
NDP event triggered route update was attempted. With threads T1 and T2:
1) T1 -> A.1, A.2
2) T2 -> B.1
3) T1 -> A.3 (hangs at A.3.1 since Stack lock is taken in step 2)
4) T2 -> B.2 (hangs at B.2.1 since integrator lock is taken in step 1)
Test: Existing tests were modified to not provide or expect routing table
changes in response to Router and Prefix discovery events.
PiperOrigin-RevId: 286274712
This change makes sure that test variables are captured before running tests
in parallel, and removes unneeded buffered channel allocations. This change also
removes unnecessary timeouts.
PiperOrigin-RevId: 286255066
Fixed a bug where the interface identifier was not properly generated from an
Ethernet address.
Tests: Unittests to make sure the functions generating the EUI64 interface
identifier are correct.
PiperOrigin-RevId: 285494562
This change adds support to let an integrator know when it receives an NDP
Router Advertisement message with the NDP Recursive DNS Server option with at
least one DNS server's address. The stack will not maintain any state related to
the DNS servers - the integrator is expected to maintain any required state and
invalidate the servers after its valid lifetime expires, or refresh the lifetime
when a new one is received for a known DNS server.
Test: Unittest to make sure that an event is sent to the integrator when an NDP
Recursive DNS Server option is received with at least one address.
PiperOrigin-RevId: 284890502
This change allows the netstack to do SLAAC as outlined by RFC 4862 section 5.5.
Note, this change will not break existing uses of netstack as the default
configuration for the stack options is set in such a way that SLAAC
will not be performed. See `stack.Options` and `stack.NDPConfigurations` for
more details.
This change reuses 1 option and introduces a new one that is required to take
advantage of SLAAC, all available under NDPConfigurations:
- HandleRAs: Whether or not NDP RAs are processes
- AutoGenGlobalAddresses: Whether or not SLAAC is performed.
Also note, this change does not deprecate SLAAC generated addresses after the
preferred lifetime. That will come in a later change (b/143713887). Currently,
only the valid lifetime is honoured.
Tests: Unittest to make sure that SLAAC generates and adds addresses only when
configured to do so. Tests also makes sure that conflicts with static addresses
do not modify the static address.
PiperOrigin-RevId: 284265317
This change drops TCP packets with a non-unicast IP address as the source or
destination address as TCP is meant for communication between two endpoints.
Test: Make sure that if the source or destination address contains a non-unicast
address, no TCP packet is sent in response and the packet is dropped.
PiperOrigin-RevId: 280073731
This change allows the netstack to do NDP's Prefix Discovery as outlined by
RFC 4861 section 6.3.4. If configured to do so, when a new on-link prefix is
discovered, the routing table will be updated with a device route through
the nic the RA arrived at. Likewise, when such a prefix gets invalidated, the
device route will be removed.
Note, this change will not break existing uses of netstack as the default
configuration for the stack options is set in such a way that Prefix Discovery
will not be performed. See `stack.Options` and `stack.NDPConfigurations` for
more details.
This change reuses 1 option and introduces a new one that is required to take
advantage of Prefix Discovery, all available under NDPConfigurations:
- HandleRAs: Whether or not NDP RAs are processes
- DiscoverOnLinkPrefixes: Whether or not Prefix Discovery is performed (new)
Another note: for a NIC to process Prefix Information options (in Router
Advertisements), it must not be a router itself. Currently the netstack does not
have per-interface routing configuration; the routing/forwarding configuration
is controlled stack-wide. Therefore, if the stack is configured to enable
forwarding/routing, no router Advertisements (and by extension the Prefix
Information options) will be processed.
Tests: Unittest to make sure that Prefix Discovery and updates to the routing
table only occur if explicitly configured to do so. Unittest to make sure at
max stack.MaxDiscoveredOnLinkPrefixes discovered on-link prefixes are
remembered.
PiperOrigin-RevId: 280049278
This change adds explicit support for honoring the 2MSL timeout
for sockets in TIME_WAIT state. It also adds support for the
TCP_LINGER2 option that allows modification of the FIN_WAIT2
state timeout duration for a given socket.
It also adds an option to modify the Stack wide TIME_WAIT timeout
but this is only for testing. On Linux this is fixed at 60s.
Further, we also now correctly process RST's in CLOSE_WAIT and
close the socket similar to linux without moving it to error
state.
We also now handle SYN in ESTABLISHED state as per
RFC5961#section-4.1. Earlier we would just drop these SYNs.
Which can result in some tests that pass on linux to fail on
gVisor.
Netstack now honors TIME_WAIT correctly as well as handles the
following cases correctly.
- TCP RSTs in TIME_WAIT are ignored.
- A duplicate TCP FIN during TIME_WAIT extends the TIME_WAIT
and a dup ACK is sent in response to the FIN as the dup FIN
indicates potential loss of the original final ACK.
- An out of order segment during TIME_WAIT generates a dup ACK.
- A new SYN w/ a sequence number > the highest sequence number
in the previous connection closes the TIME_WAIT early and
opens a new connection.
Further to make the SYN case work correctly the ISN (Initial
Sequence Number) generation for Netstack has been updated to
be as per RFC. Its not a pure random number anymore and follows
the recommendation in https://tools.ietf.org/html/rfc6528#page-3.
The current hash used is not a cryptographically secure hash
function. A separate change will update the hash function used
to Siphash similar to what is used in Linux.
PiperOrigin-RevId: 279106406
This change allows the netstack to do NDP's Router Discovery as outlined by
RFC 4861 section 6.3.4.
Note, this change will not break existing uses of netstack as the default
configuration for the stack options is set in such a way that Router Discovery
will not be performed. See `stack.Options` and `stack.NDPConfigurations` for
more details.
This change introduces 2 options required to take advantage of Router Discovery,
all available under NDPConfigurations:
- HandleRAs: Whether or not NDP RAs are processes
- DiscoverDefaultRouters: Whether or not Router Discovery is performed
Another note: for a NIC to process Router Advertisements, it must not be a
router itself. Currently the netstack does not have per-interface routing
configuration; the routing/forwarding configuration is controlled stack-wide.
Therefore, if the stack is configured to enable forwarding/routing, no Router
Advertisements will be processed.
Tests: Unittest to make sure that Router Discovery and updates to the routing
table only occur if explicitly configured to do so. Unittest to make sure at
max stack.MaxDiscoveredDefaultRouters discovered default routers are remembered.
PiperOrigin-RevId: 278965143
This change validates incoming NDP Router Advertisements as per RFC 4861 section
6.1.2. It also includes the skeleton to handle Router Advertiements that arrive
on some NIC.
Tests: Unittest to make sure only valid NDP Router Advertisements are received/
not dropped.
PiperOrigin-RevId: 278891972
When VectorisedViews were passed up the stack from packet_dispatchers, we were
passing a sub-slice of the dispatcher's views fields. The dispatchers then
immediately set those views to nil.
This wasn't caught before because every implementer copied the data in these
views before returning.
PiperOrigin-RevId: 277615351
In the future this will replace DanglingEndpoints. DanglingEndpoints must be
kept for now due to issues with save/restore.
This is arguably a cleaner design and allows the stack to know which transport
endpoints might still be using its link endpoints.
Updates #837
PiperOrigin-RevId: 277386633
This change supports using a user supplied TCP MSS for new active TCP
connections. Note, the user supplied MSS must be less than or equal to the
maximum possible MSS for a TCP connection's route. If it is greater than the
maximum possible MSS, the maximum possible MSS will be used as the connection's
MSS instead.
This change does not use this user supplied MSS for connections accepted from
listening sockets - that will come in a later change.
Test: Test that outgoing TCP SYN segments contain a TCP MSS option with the user
supplied MSS if it is not greater than the maximum possible MSS for the route.
PiperOrigin-RevId: 277185125
This change makes it so that NDP work is done using the per-interface NDP
configurations instead of the stack-wide default NDP configurations to correctly
implement RFC 4861 section 6.3.2 (note here, a host is a single NIC operating
as a host device), and RFC 4862 section 5.1.
Test: Test that we can set NDP configurations on a per-interface basis without
affecting the configurations of other interfaces or the stack-wide default. Also
make sure that after the configurations are updated, the updated configurations
are used for NDP processes (e.g. Duplicate Address Detection).
PiperOrigin-RevId: 276525661
This change introduces a new interface, stack.NDPDispatcher. It can be
implemented by the netstack integrator to receive NDP related events. As of this
change, only DAD related events are supported.
Tests: Existing tests were modified to use the NDPDispatcher's DAD events for
DAD tests where it needed to wait for DAD completing (failing and resolving).
PiperOrigin-RevId: 276338733
This change makes sure that when an address which is already known by a NIC and
has kind = permanentExpired gets promoted to permanent, the new
PrimaryEndpointBehavior is respected.
PiperOrigin-RevId: 276136317
Right now, we send each tcp packet separately, we call one system
call per-packet. This patch allows to generate multiple tcp packets
and send them by sendmmsg.
The arguable part of this CL is a way how to handle multiple headers.
This CL adds the next field to the Prepandable buffer.
Nginx test results:
Server Software: nginx/1.15.9
Server Hostname: 10.138.0.2
Server Port: 8080
Document Path: /10m.txt
Document Length: 10485760 bytes
w/o gso:
Concurrency Level: 5
Time taken for tests: 5.491 seconds
Complete requests: 100
Failed requests: 0
Total transferred: 1048600200 bytes
HTML transferred: 1048576000 bytes
Requests per second: 18.21 [#/sec] (mean)
Time per request: 274.525 [ms] (mean)
Time per request: 54.905 [ms] (mean, across all concurrent requests)
Transfer rate: 186508.03 [Kbytes/sec] received
sw-gso:
Concurrency Level: 5
Time taken for tests: 3.852 seconds
Complete requests: 100
Failed requests: 0
Total transferred: 1048600200 bytes
HTML transferred: 1048576000 bytes
Requests per second: 25.96 [#/sec] (mean)
Time per request: 192.576 [ms] (mean)
Time per request: 38.515 [ms] (mean, across all concurrent requests)
Transfer rate: 265874.92 [Kbytes/sec] received
w/o gso:
$ ./tcp_benchmark --client --duration 15 --ideal
[SUM] 0.0-15.1 sec 2.20 GBytes 1.25 Gbits/sec
software gso:
$ tcp_benchmark --client --duration 15 --ideal --gso $((1<<16)) --swgso
[SUM] 0.0-15.1 sec 3.99 GBytes 2.26 Gbits/sec
PiperOrigin-RevId: 276112677
This change adds support for optionally auto-generating an IPv6 link-local
address based on the NIC's MAC Address on NIC enable.
Note, this change will not break existing uses of netstack as the default
configuration for the stack options is set in such a way that a link-local
address will not be auto-generated unless the stack is explicitly configured.
See `stack.Options` for more details. Specifically, see
`stack.Options.AutoGenIPv6LinkLocal`.
Tests: Tests to make sure that the IPb6 link-local address is only
auto-generated if the stack is specifically configured to do so. Also tests to
make sure that an auto-generated address goes through the DAD process.
PiperOrigin-RevId: 276059813
Like (AF_INET, SOCK_RAW) sockets, AF_PACKET sockets require CAP_NET_RAW. With
runsc, you'll need to pass `--net-raw=true` to enable them.
Binding isn't supported yet.
PiperOrigin-RevId: 275909366
It is quite legal to send from the ANY address (it is required for
DHCP). I can't figure out why the broadcast address was included here,
so removing that as well.
PiperOrigin-RevId: 275541954
NDP Neighbor Solicitations sent during Duplicate Address Detection must have an
IP hop limit of 255, as all NDP Neighbor Solicitations should have.
Test: Test that DAD messages have the IPv6 hop limit field set to 255.
PiperOrigin-RevId: 275321680
This change adds support for Duplicate Address Detection on IPv6 addresses
as defined by RFC 4862 section 5.4.
Note, this change will not break existing uses of netstack as the default
configuration for the stack options is set in such a way that DAD will not be
performed. See `stack.Options` and `stack.NDPConfigurations` for more details.
Tests: Tests to make sure that the DAD process properly resolves or fails.
That is, tests make sure that DAD resolves only if:
- No other node is performing DAD for the same address
- No other node owns the same address
PiperOrigin-RevId: 275189471
...and do not populate link address cache at dispatch. This partially
reverts 313c767b00, which caused malformed
packets (e.g. NDP Neighbor Adverts with incorrect hop limit values) to
populate the address cache. In particular, this masked a bug that was
introduced to the Neighbor Advert generation code in
7c1587e340.
PiperOrigin-RevId: 274865182
The behavior for sending and receiving local broadcast (255.255.255.255)
traffic is as follows:
Outgoing
--------
* A broadcast packet sent on a socket that is bound to an interface goes out
that interface
* A broadcast packet sent on an unbound socket follows the route table to
select the outgoing interface
+ if an explicit route entry exists for 255.255.255.255/32, use that one
+ else use the default route
* Broadcast packets are looped back and delivered following the rules for
incoming packets (see next). This is the same behavior as for multicast
packets, except that it cannot be disabled via sockopt.
Incoming
--------
* Sockets wishing to receive broadcast packets must bind to either INADDR_ANY
(0.0.0.0) or INADDR_BROADCAST (255.255.255.255). No other socket receives
broadcast packets.
* Broadcast packets are multiplexed to all sockets matching it. This is the
same behavior as for multicast packets.
* A socket can bind to 255.255.255.255:<port> and then receive its own
broadcast packets sent to 255.255.255.255:<port>
In addition, this change implicitly fixes an issue with multicast reception. If
two sockets want to receive a given multicast stream and one is bound to ANY
while the other is bound to the multicast address, only one of them will
receive the traffic.
PiperOrigin-RevId: 272792377
Netstack always picks a random start point everytime PickEphemeralPort
is called. While this is required for UDP so that DNS requests go
out through a randomized set of ports it is not required for TCP. Infact
Linux explicitly hashes the (srcip, dstip, dstport) and a one time secret
initialized at start of the application to get a random offset. But to
ensure it doesn't start from the same point on every scan it uses a static
hint that is incremented by 2 in every call to pick ephemeral ports.
The reason for 2 is Linux seems to split the port ranges where active connects
seem to use even ones while odd ones are used by listening sockets.
This CL implements a similar strategy where we use a hash + hint to generate
the offset to start the search for a free Ephemeral port.
This ensures that we cycle through the available port space in order for
repeated connects to the same destination and significantly reduces the
chance of picking a recently released port.
PiperOrigin-RevId: 272058370
Non-primary addresses are used for endpoints created to accept multicast and
broadcast packets, as well as "helper" endpoints (0.0.0.0) that allow sending
packets when no proper address has been assigned yet (e.g., for DHCP). These
addresses are not real addresses from a user point of view and should not be
part of the NICInfo() value. Also see b/127321246 for more info.
This switches NICInfo() to call a new NIC.PrimaryAddresses() function. To still
allow an option to get all addresses (mostly for testing) I added
Stack.GetAllAddresses() and NIC.AllAddresses().
In addition, the return value for GetMainNICAddress() was changed for the case
where the NIC has no primary address. Instead of returning an error here,
it now returns an empty AddressWithPrefix() value. The rational for this
change is that it is a valid case for a NIC to have no primary addresses.
Lastly, I refactored the code based on the new additions.
PiperOrigin-RevId: 270971764
Previously, the only safe way to use an fdbased endpoint was to leak the FD.
This change makes it possible to safely close the FD.
This is the first step towards having stoppable stacks.
Updates #837
PiperOrigin-RevId: 270346582
This also allows the tee(2) implementation to be enabled, since dup can now be
properly supported via WriteTo.
Note that this change necessitated some minor restructoring with the
fs.FileOperations splice methods. If the *fs.File is passed through directly,
then only public API methods are accessible, which will deadlock immediately
since the locking is already done by fs.Splice. Instead, we pass through an
abstract io.Reader or io.Writer, which elide locks and use the underlying
fs.FileOperations directly.
PiperOrigin-RevId: 268805207
The IPv6 all-nodes multicast address will be joined on NIC enable, and the
appropriate IPv6 solicited-node multicast address will be joined when IPv6
addresses are added.
Tests: Test receiving packets destined to the IPv6 link-local all-nodes
multicast address and the IPv6 solicted node address of an added IPv6 address.
PiperOrigin-RevId: 268047073
This also renames "subnet" to "addressRange" to avoid any more confusion with
an interface IP's subnet.
Lastly, this also removes the Stack.ContainsSubnet(..) API since it isn't used
by anyone. Plus the same information can be obtained from
Stack.NICAddressRanges().
PiperOrigin-RevId: 267229843
Adds support to generate Port Unreachable messages for UDP
datagrams received on a port for which there is no valid
endpoint.
Fixes#703
PiperOrigin-RevId: 267034418
This allows the stack to learn remote link addresses on incoming
packets, reducing the need to ARP to send responses.
This also reduces the number of round trips to the system clock,
since that may also prove to be performance-sensitive.
Fixes#739.
PiperOrigin-RevId: 265815816
This addresses the problem where an endpoint has its address removed but still
has outstanding references held by routes used in connected TCP/UDP sockets
which prevent the removal of the endpoint.
The fix adds a new "expired" flag to the referenced network endpoint, which is
set when an endpoint has its address removed. Incoming packets are not
delivered to an expired endpoint (unless in promiscuous mode), while sending
outgoing packets triggers an error to the caller (unless in spoofing mode).
In addition, a few helper functions were added to stack_test.go to reduce
code duplications.
PiperOrigin-RevId: 265514326
This adds the same logic to NIC.findEndpoint that is already done in
NIC.getRef. Since this makes the two functions very similar they were combined
into one with the originals being wrappers.
PiperOrigin-RevId: 263864708
Endpoint protocol goroutines were previously started as part of
loading the endpoint. This is potentially too soon, as resources used
by these goroutine may not have been loaded. Protocol goroutines may
perform meaningful work as soon as they're started (ex: incoming
connect) which can cause them to indirectly access resources that
haven't been loaded yet.
This CL defers resuming all protocol goroutines until the end of
restore.
PiperOrigin-RevId: 262409429
This allows the user code to add a network address with a subnet prefix length.
The prefix length value is stored in the network endpoint and provided back to
the user in the ProtocolAddress type.
PiperOrigin-RevId: 259807693
iptables also relies on IPPROTO_RAW in a way. It opens such a socket to
manipulate the kernel's tables, but it doesn't actually use any of the
functionality. Blegh.
PiperOrigin-RevId: 257903078
The implementation is similar to linux where we track the number of bytes
consumed by the application to grow the receive buffer of a given TCP endpoint.
This ensures that the advertised window grows at a reasonable rate to accomodate
for the sender's rate and prevents large amounts of data being held in stack
buffers if the application is not actively reading or not reading fast enough.
The original paper that was used to implement the linux receive buffer auto-
tuning is available @ https://public.lanl.gov/radiant/pubs/drs/lacsi2001.pdf
NOTE: Linux does not implement DRS as defined in that paper, it's just a good
reference to understand the solution space.
Updates #230
PiperOrigin-RevId: 253168283
This is necessary for implementing network diagnostic interfaces like
/proc/net/{tcp,udp,unix} and sock_diag(7).
For pass-through endpoints such as hostinet, we obtain the socket
state from the backend. For netstack, we add explicit tracking of TCP
states.
PiperOrigin-RevId: 251934850
Ghanan Gowripalan
Bhasker Hariharan
Tamir Duberstein
Kevin Krakauer
Ian Gudger
Eyal Soha
Bert Muthalaly
gVisor bot
Ryan Heacock
Adin Scannell
Andrei Vagin
Chris Kuiper
Michael Pratt
Rahat Mahmood