The specific issue was:
- Test creates a raw ICMP socket
- Test sends an ICMP echo request (aka ping request) to itself via loopback
- Now two events race:
- The raw socket recieves the ICMP echo request
- Netstack receives the request and generates a reply (aka ping reply),
which it sends back over loopback, where it is eventually received by the
raw socket
- The test was written to expect packets in a specific order, but they can
come in any order.
PiperOrigin-RevId: 236179066
Change-Id: I02c07c919d3d28093add3d18dd9196fbbc870813
Broadly, this change:
* Enables sockets to be created via `socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)`.
* Passes the network-layer (IP) header up the stack to the transport endpoint,
which can pass it up to the socket layer. This allows a raw socket to return
the entire IP packet to users.
* Adds functions to stack.TransportProtocol, stack.Stack, stack.transportDemuxer
that enable incoming packets to be delivered to raw endpoints. New raw sockets
of other protocols (not ICMP) just need to register with the stack.
* Enables ping.endpoint to return IP headers when created via SOCK_RAW.
PiperOrigin-RevId: 235993280
Change-Id: I60ed994f5ff18b2cbd79f063a7fdf15d093d845a
Kevin Krakauer