tools/testing/selftests/net/packetdrill/tcp_zerocopy_fastopen-server.pkt

Source file repositories/reference/linux-study-clean/tools/testing/selftests/net/packetdrill/tcp_zerocopy_fastopen-server.pkt

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/net/packetdrill/tcp_zerocopy_fastopen-server.pkt
Extension
.pkt
Size
1715 bytes
Lines
47
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: tools
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
// Fastopen server zerocopy test:
//
// send data with MSG_FASTOPEN | MSG_ZEROCOPY and verify that the
// kernel returns the notification ID.

--send_omit_free	// do not reuse send buffers with zerocopy

`./defaults.sh
 ./set_sysctls.py /proc/sys/net/ipv4/tcp_fastopen=0x207`

// Set up a TFO server listening socket.
    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
  +.1 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
   +0 bind(3, ..., ...) = 0
   +0 listen(3, 1) = 0
   +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN, [2], 4) = 0
   +0 setsockopt(3, SOL_SOCKET, SO_ZEROCOPY, [1], 4) = 0

// Client sends a SYN with data.
  +.1 < S 0:1000(1000) win 32792 <mss 1460,sackOK,nop,nop>
   +0 > S. 0:0(0) ack 1001 <mss 1460,nop,nop,sackOK>

// Server accepts and replies with data.
+.005 accept(3, ..., ...) = 4
   +0 read(4, ..., 1024) = 1000
   +0 sendto(4, ..., 1000, MSG_ZEROCOPY, ..., ...) = 1000
   +0 > P. 1:1001(1000) ack 1001
 +.05 < . 1001:1001(0) ack 1001 win 32792

// Read from error queue: now has first zerocopy notification
  +0.1 recvmsg(4, {msg_name(...)=...,
                  msg_iov(1)=[{...,0}],
                  msg_flags=MSG_ERRQUEUE,
                  msg_control=[
                      {cmsg_level=CMSG_LEVEL_IP,
                       cmsg_type=CMSG_TYPE_RECVERR,
                       cmsg_data={ee_errno=0,
                                  ee_origin=SO_EE_ORIGIN_ZEROCOPY,
                                  ee_type=0,
                                  ee_code=SO_EE_CODE_ZEROCOPY_COPIED,
                                  ee_info=0,
                                  ee_data=0}}
                  ]}, MSG_ERRQUEUE) = 0

`/tmp/sysctl_restore_${PPID}.sh`

Annotation

Implementation Notes