| Age | Commit message (Collapse) | Author |
|---|
|
This makes it possible to add data to types that implement tcpip.Error.
ErrBadLinkEndpoint is removed as it is unused.
PiperOrigin-RevId: 354437314
|
|
As per RFC 4861 section 7.3.1,
A neighbor is considered reachable if the node has recently received
a confirmation that packets sent recently to the neighbor were
received by its IP layer. Positive confirmation can be gathered in
two ways: hints from upper-layer protocols that indicate a connection
is making "forward progress", or receipt of a Neighbor Advertisement
message that is a response to a Neighbor Solicitation message.
This change adds support for TCP to let the IP/link layers know that a
neighbor is reachable.
Test: integration_test.TestTCPConfirmNeighborReachability
PiperOrigin-RevId: 354222833
|
|
GetLinkAddress's callback will be called immediately with a
stack.LinkResolutionResult which will hold the link address
so no need to also return the link address from the function.
Fixes #5151.
PiperOrigin-RevId: 353157857
|
|
...unless explicitly requested via ResolveWith.
Remove cancelled channels from pending packets as we can use the link
resolution channel in a FIFO to limit the number of maximum pending
resolutions we should queue packets for.
This change also defers starting the goroutine that handles link
resolution completion to when link resolution succeeds, fails or
gets cancelled due to the max number of pending resolutions being
reached.
Fixes #751.
PiperOrigin-RevId: 353130577
|
|
Test: integration_test.TestWritePacketsLinkResolution
Fixes #4458.
PiperOrigin-RevId: 353108826
|
|
fdbased and qdisc layers expect these fields to already be
populated before being reached.
PiperOrigin-RevId: 353099492
|
|
Link addresses are cached on a per NIC basis so instead of having a
single cache that includes the NIC ID for neighbor entry lookups,
use a single cache per NIC.
PiperOrigin-RevId: 352684111
|
|
Packets may be pending on link resolution to complete before being sent.
Link resolution is performed for neighbors which are unique to a NIC so
hold link resolution related state under the NIC, not the stack.
Note, this change may result in more queued packets but that is okay as
RFC 4861 section 7.2.2 recommends that the stack maintain a queue of
packets for each neighbor that is waiting for link resolution to
complete, not a fixed limit per stack.
PiperOrigin-RevId: 352322155
|
|
Test: integration_test.TestGetLinkAddress
PiperOrigin-RevId: 352119404
|
|
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
|
|
Note, this includes static entries to match linux's behaviour.
```
$ ip neigh show dev eth0
192.168.42.1 lladdr fc:ec:da:70:6e:f9 STALE
$ sudo ip neigh add 192.168.42.172 lladdr 22:33:44:55:66:77 dev eth0
$ ip neigh show dev eth0
192.168.42.1 lladdr fc:ec:da:70:6e:f9 STALE
192.168.42.172 lladdr 22:33:44:55:66:77 PERMANENT
$ sudo ifconfig eth0 down
$ ip neigh show dev eth0
$ sudo ifconfig eth0 up
$ ip neigh show dev eth0
```
Test: stack_test.TestClearNeighborCacheOnNICDisable
PiperOrigin-RevId: 351696306
|
|
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
|
|
packetEPs may get into a state that `len < cap`, casuing append() modifying the
original slice storage.
Reported-by: syzbot+978dd0e9c2600ab7a76b@syzkaller.appspotmail.com
PiperOrigin-RevId: 347634351
|
|
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, #4861
Fixes #4888
Startblock:
has LGTM from peterjohnston
and then
add reviewer brunodalbo
PiperOrigin-RevId: 346869702
|
|
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
|
|
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, #4861
Fixes #4916
PiperOrigin-RevId: 345019091
|
|
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
|
|
Add a NIC-specific neighbor table statistic so we can determine how many
packets have been queued to Failed neighbors, indicating an unhealthy local
network. This change assists us to debug in-field issues where subsequent
traffic to a neighbor fails.
Fixes #4819
PiperOrigin-RevId: 344131119
|
|
- 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
|
|
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
|
|
* 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 #4688
Fixes #3906
PiperOrigin-RevId: 340943442
|
|
PiperOrigin-RevId: 339945377
|
|
PiperOrigin-RevId: 339750876
|
|
Refactor TCP handshake code so that when connect is initiated, the initial SYN
is sent before creating a goroutine to handle the rest of the handshake (which
blocks). Similarly, the initial SYN-ACK is sent inline when SYN is received
during accept.
Some additional cleanup is done as well.
Eventually we would like to complete connections in the dispatcher without
requiring a wakeup to complete the handshake. This refactor makes that easier.
Updates #231
PiperOrigin-RevId: 339675182
|
|
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
|
|
Previously a link endpoint was passed to
stack.LinkAddressResolver.LinkAddressRequest. With this change,
implementations that want a route for the link address request may
find one through the stack. Other implementations that want to send
a packet without a route may continue to do so using the network
interface directly.
Test: - arp_test.TestLinkAddressRequest
- ipv6.TestLinkAddressRequest
PiperOrigin-RevId: 338577474
|
|
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
|
|
PiperOrigin-RevId: 336339194
|
|
PiperOrigin-RevId: 336304024
|
|
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
|
|
We can get the network endpoint directly from the NIC.
This is a preparatory CL for when a Route needs to hold a dedicated NIC
as its output interface. This is because when forwarding is enabled,
packets may be sent from a NIC different from the NIC a route's local
address is associated with.
PiperOrigin-RevId: 335484500
|
|
Add code in IPv6 to send ICMP packets while processing extension headers.
Add some accounting in processing IPV6 Extension headers which
allows us to report meaningful information back in ICMP parameter
problem packets.
IPv4 also needs to send a message when an unsupported protocol
is requested.
Add some tests to generate both ipv4 and ipv6 packets with
various errors and check the responses.
Add some new checkers and cleanup some inconsistencies in
the messages in that file.
Add new error types for the ICMPv4/6 generators.
Fix a bug in the ICMPv4 generator that stopped it from generating
"Unknown protocol" messages.
Updates #2211
PiperOrigin-RevId: 334661716
|
|
Test: stack_test.TestGetMainNICAddressWhenNICDisabled
PiperOrigin-RevId: 334513286
|
|
* Remove Capabilities and NICID methods from NetworkEndpoint.
* Remove linkEP and stack parameters from NetworkProtocol.NewEndpoint.
The LinkEndpoint can be fetched from the NetworkInterface. The stack
is passed to the NetworkProtocol when it is created so the
NetworkEndpoint can get it from its protocol.
* Remove stack parameter from TransportProtocol.NewEndpoint.
Like the NetworkProtocol/Endpoint, the stack is passed to the
TransportProtocol when it is created.
PiperOrigin-RevId: 334332721
|
|
* Add network address to network endpoints.
Hold network-specific state in the NetworkEndpoint instead of the stack.
This results in the stack no longer needing to "know" about the network
endpoints and special case certain work for various endpoints
(e.g. IPv6 DAD).
* Provide NetworkEndpoints with an NetworkInterface interface.
Instead of just passing the NIC ID of a NIC, pass an interface so the
network endpoint may query other information about the NIC such as
whether or not it is a loopback device.
* Move NDP code and state to the IPv6 package.
NDP is IPv6 specific so there is no need for it to live in the stack.
* Control forwarding through NetworkProtocols instead of Stack
Forwarding should be controlled on a per-network protocol basis so
forwarding configurations are now controlled through network protocols.
* Remove stack.referencedNetworkEndpoint.
Now that addresses are exposed via AddressEndpoint and only one
NetworkEndpoint is created per interface, there is no need for a
referenced NetworkEndpoint.
* Assume network teardown methods are infallible.
Fixes #3871, #3916
PiperOrigin-RevId: 334319433
|
|
Generic ICMP errors were required because the transport dispatcher was
given the responsibility of sending ICMP errors in response to transport
packet delivery failures. Instead, the transport dispatcher should let
network layer know it failed to deliver a packet (and why) and let the
network layer make the decision as to what error to send (if any).
Fixes #4068
PiperOrigin-RevId: 333962333
|
|
Store transport protocol number on packet buffers for use in ICMP error
generation.
Updates #2211.
PiperOrigin-RevId: 333252762
|
|
PiperOrigin-RevId: 332760843
|
|
PiperOrigin-RevId: 332486383
|
|
`ip6tables -t filter` is now usable. NAT support will come in a future CL.
#3549
PiperOrigin-RevId: 332381801
|
|
The lifetime of addreses in a loopback interface's associated subnets
should be bound to their respective permanent addresses.
This change also fixes a race when the stack attempts to get an IPv4
rereferencedNetworkEndpoint for an address in an associated subnet on
a loopback interface. Before this change, the stack would only check
if an IPv4 address is contained in an associated subnet while holding
a read lock but wouldn't do this same check after releasing the read
lock for a write lock to create a temporary address. This may cause
the stack to bind the lifetime of the address to a new (temporary)
endpoint instead of the associated subnet's permanent address.
Test: integration_test.TestLoopbackSubnetLifetimeBoundToAddr
PiperOrigin-RevId: 332094719
|
|
An earlier change considered the loopback bound to all addresses in an
assigned subnet. This should have only be done for IPv4 to maintain
compatability with Linux:
```
$ ip addr show dev lo
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group ...
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
$ ping 2001:db8::1
PING 2001:db8::1(2001:db8::1) 56 data bytes
^C
--- 2001:db8::1 ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 3062ms
$ ping 2001:db8::2
PING 2001:db8::2(2001:db8::2) 56 data bytes
^C
--- 2001:db8::2 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2030ms
$ sudo ip addr add 2001:db8::1/64 dev lo
$ ping 2001:db8::1
PING 2001:db8::1(2001:db8::1) 56 data bytes
64 bytes from 2001:db8::1: icmp_seq=1 ttl=64 time=0.055 ms
64 bytes from 2001:db8::1: icmp_seq=2 ttl=64 time=0.074 ms
64 bytes from 2001:db8::1: icmp_seq=3 ttl=64 time=0.073 ms
64 bytes from 2001:db8::1: icmp_seq=4 ttl=64 time=0.071 ms
^C
--- 2001:db8::1 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3075ms
rtt min/avg/max/mdev = 0.055/0.068/0.074/0.007 ms
$ ping 2001:db8::2
PING 2001:db8::2(2001:db8::2) 56 data bytes
From 2001:db8::1 icmp_seq=1 Destination unreachable: No route
From 2001:db8::1 icmp_seq=2 Destination unreachable: No route
From 2001:db8::1 icmp_seq=3 Destination unreachable: No route
From 2001:db8::1 icmp_seq=4 Destination unreachable: No route
^C
--- 2001:db8::2 ping statistics ---
4 packets transmitted, 0 received, +4 errors, 100% packet loss, time 3070ms
```
Test: integration_test.TestLoopbackAcceptAllInSubnet
PiperOrigin-RevId: 329011566
|
|
This change was already done as of
https://github.com/google/gvisor/commit/1736b2208f but
https://github.com/google/gvisor/commit/a174aa7597 conflicted with that
change and it was missed in reviews.
This change fixes the conflict.
PiperOrigin-RevId: 328920372
|
|
This change adds an option to replace the current implementation of ARP through
linkAddrCache, with an implementation of NUD through neighborCache. Switching
to using NUD for both ARP and NDP is beneficial for the reasons described by
RFC 4861 Section 3.1:
"[Using NUD] significantly improves the robustness of packet delivery in the
presence of failing routers, partially failing or partitioned links, or nodes
that change their link-layer addresses. For instance, mobile nodes can move
off-link without losing any connectivity due to stale ARP caches."
"Unlike ARP, Neighbor Unreachability Detection detects half-link failures and
avoids sending traffic to neighbors with which two-way connectivity is
absent."
Along with these changes exposes the API for querying and operating the
neighbor cache. Operations include:
- Create a static entry
- List all entries
- Delete all entries
- Remove an entry by address
This also exposes the API to change the NUD protocol constants on a per-NIC
basis to allow Neighbor Discovery to operate over links with widely varying
performance characteristics. See [RFC 4861 Section 10][1] for the list of
constants.
Finally, an API for subscribing to NUD state changes is exposed through
NUDDispatcher. See [RFC 4861 Appendix C][3] for the list of edges.
Tests:
pkg/tcpip/network/arp:arp_test
+ TestDirectRequest
pkg/tcpip/network/ipv6:ipv6_test
+ TestLinkResolution
+ TestNDPValidation
+ TestNeighorAdvertisementWithTargetLinkLayerOption
+ TestNeighorSolicitationResponse
+ TestNeighorSolicitationWithSourceLinkLayerOption
+ TestRouterAdvertValidation
pkg/tcpip/stack:stack_test
+ TestCacheWaker
+ TestForwardingWithFakeResolver
+ TestForwardingWithFakeResolverManyPackets
+ TestForwardingWithFakeResolverManyResolutions
+ TestForwardingWithFakeResolverPartialTimeout
+ TestForwardingWithFakeResolverTwoPackets
+ TestIPv6SourceAddressSelectionScopeAndSameAddress
[1]: https://tools.ietf.org/html/rfc4861#section-10
[2]: https://tools.ietf.org/html/rfc4861#appendix-C
Fixes #1889
Fixes #1894
Fixes #1895
Fixes #1947
Fixes #1948
Fixes #1949
Fixes #1950
PiperOrigin-RevId: 328365034
|
|
When a loopback interface is configurd with an address and associated
subnet, the loopback should treat all addresses in that subnet as an
address it owns.
This is mimicking linux behaviour as seen below:
```
$ ip addr show dev lo
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group ...
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
$ ping 192.0.2.1
PING 192.0.2.1 (192.0.2.1) 56(84) bytes of data.
^C
--- 192.0.2.1 ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 1018ms
$ ping 192.0.2.2
PING 192.0.2.2 (192.0.2.2) 56(84) bytes of data.
^C
--- 192.0.2.2 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2039ms
$ sudo ip addr add 192.0.2.1/24 dev lo
$ ip addr show dev lo
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group ...
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet 192.0.2.1/24 scope global lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
$ ping 192.0.2.1
PING 192.0.2.1 (192.0.2.1) 56(84) bytes of data.
64 bytes from 192.0.2.1: icmp_seq=1 ttl=64 time=0.131 ms
64 bytes from 192.0.2.1: icmp_seq=2 ttl=64 time=0.046 ms
64 bytes from 192.0.2.1: icmp_seq=3 ttl=64 time=0.048 ms
^C
--- 192.0.2.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2042ms
rtt min/avg/max/mdev = 0.046/0.075/0.131/0.039 ms
$ ping 192.0.2.2
PING 192.0.2.2 (192.0.2.2) 56(84) bytes of data.
64 bytes from 192.0.2.2: icmp_seq=1 ttl=64 time=0.131 ms
64 bytes from 192.0.2.2: icmp_seq=2 ttl=64 time=0.069 ms
64 bytes from 192.0.2.2: icmp_seq=3 ttl=64 time=0.049 ms
64 bytes from 192.0.2.2: icmp_seq=4 ttl=64 time=0.035 ms
^C
--- 192.0.2.2 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3049ms
rtt min/avg/max/mdev = 0.035/0.071/0.131/0.036 ms
```
Test: integration_test.TestLoopbackAcceptAllInSubnet
PiperOrigin-RevId: 328188546
|
|
- Merges aleksej-paschenko's with HEAD
- Adds vfs2 support for ip_forward
|
|
Should have been removed in cl/326791119
https://github.com/google/gvisor/commit/9a7b5830aa063895f67ca0fdf653a46906374613
PiperOrigin-RevId: 327074156
|
|
Previously the netstack supported assignment of a range of addresses.
This feature is not used so remove it.
PiperOrigin-RevId: 326791119
|
|
The NetworkEndpoint does not need to be created for each address.
Most of the work the NetworkEndpoint does is address agnostic.
PiperOrigin-RevId: 326759605
|
|
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
|
