selftest: packetdrill: Import TFO server basic tests.

This imports basic TFO server tests from google/packetdrill.

The repository has two versions of tests for most scenarios; one uses
the non-experimental option (34), and the other uses the experimental
option (255) with 0xF989.

This only imports the following tests of the non-experimental version
placed in [0].  I will add a specific test for the experimental option
handling later.

                             | TFO | Cookie | Payload |
  ---------------------------+-----+--------+---------+
  basic-rw.pkt               | yes |  yes   |   yes   |
  basic-zero-payload.pkt     | yes |  yes   |    no   |
  basic-cookie-not-reqd.pkt  | yes |   no   |   yes   |
  basic-non-tfo-listener.pkt |  no |  yes   |   yes   |
  pure-syn-data.pkt          | yes |   no   |   yes   |

The original pure-syn-data.pkt missed setsockopt(TCP_FASTOPEN) and did
not test TFO server in some scenarios unintentionally, so setsockopt()
is added where needed.  In addition, non-TFO scenario is stripped as
it is covered by basic-non-tfo-listener.pkt.  Also, I added basic- prefix.

Link: https://github.com/google/packetdrill/tree/bfc96251310f/gtests/net/tcp/fastopen/server/opt34 #[0]
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250927213022.1850048-5-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/packetdrill/tcp_fastopen_server_basic-cookie-not-reqd.pkt

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Basic TFO server test
+//
+// Test TFO_SERVER_COOKIE_NOT_REQD flag on receiving
+// SYN with data but without Fast Open cookie option.
+
+`./defaults.sh
+ ./set_sysctls.py /proc/sys/net/ipv4/tcp_fastopen=0x202`
+
+    0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
+   +0 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, [1], 4) = 0
+
+// Since TFO_SERVER_COOKIE_NOT_REQD, a TFO socket will be created with
+// the data accepted.
+   +0 < S 0:1000(1000) win 32792 <mss 1460,sackOK,nop,nop>
+   +0 > S. 0:0(0) ack 1001 <mss 1460,nop,nop,sackOK>
+   +0 accept(3, ..., ...) = 4
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) != 0, tcpi_options }%
+   +0 read(4, ..., 1024) = 1000
+
+// Data After SYN will be accepted too.
+   +0 < . 1001:2001(1000) ack 1 win 5840
+   +0 > . 1:1(0) ack 2001
+
+// Should change the implementation later to set the SYN flag as well.
+   +0 read(4, ..., 1024) = 1000
+   +0 write(4, ..., 1000) = 1000
+   +0 > P. 1:1001(1000) ack 2001

tools/testing/selftests/net/packetdrill/tcp_fastopen_server_basic-non-tfo-listener.pkt

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Basic TFO server test
+//
+// Server w/o TCP_FASTOPEN socket option
+
+`./defaults.sh`
+
+    0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
+   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
+   +0 bind(3, ..., ...) = 0
+   +0 listen(3, 1) = 0
+
+   +0 < S 0:10(10) win 32792 <mss 1460,sackOK,FO TFO_COOKIE>
+
+// Data is ignored since TCP_FASTOPEN is not set on the listener
+   +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK>
+
+   +0 accept(3, ..., ...) = -1 EAGAIN (Resource temporarily unavailable)
+
+// The above should block until ack comes in below.
+   +0 < . 1:31(30) ack 1 win 5840
+   +0 accept(3, ..., ...) = 4
+
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) == 0, tcpi_options }%
+   +0 read(4, ..., 512) = 30

tools/testing/selftests/net/packetdrill/tcp_fastopen_server_basic-pure-syn-data.pkt

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Basic TFO server test
+//
+// Test that TFO-enabled server would not respond SYN-ACK with any TFO option
+// when receiving a pure SYN-data. It should respond a pure SYN-ack.
+
+`./defaults.sh`
+
+    0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
+   +0 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, [1], 4) = 0
+
+   +0 < S 999000:999040(40) win 32792 <mss 1460,sackOK,TS val 100 ecr 100,nop,wscale 6>
+   +0 > S. 1234:1234(0) ack 999001 <mss 1460,sackOK,TS val 100 ecr 100,nop,wscale 8>
+   +0 < . 1:1(0) ack 1 win 100
+   +0 accept(3, ..., ...) = 4
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) == 0, tcpi_options }%
+   +0 close(3) = 0
+
+// Test ECN-setup SYN with ECN disabled because this has happened in reality
+   +0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
+   +0 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, [1], 4) = 0
+
+   +0 < SEW 999000:999040(40) win 32792 <mss 1460,sackOK,TS val 100 ecr 100,nop,wscale 6>
+   +0 > S. 1234:1234(0) ack 999001 <mss 1460,sackOK,TS val 100 ecr 100,nop,wscale 8>
+   +0 < . 1:1(0) ack 1 win 100
+   +0 accept(3, ..., ...) = 4
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) == 0, tcpi_options }%
+   +0 close(3) = 0
+
+// Test ECN-setup SYN w/ ECN enabled
+   +0 `sysctl -q net.ipv4.tcp_ecn=2`
+   +0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
+   +0 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, [1], 4) = 0
+
+   +0 < SEW 999000:999040(40) win 32792 <mss 1460,sackOK,TS val 100 ecr 100,nop,wscale 6>
+   +0 > SE. 1234:1234(0) ack 999001 <mss 1460,sackOK,TS val 100 ecr 100,nop,wscale 8>
+   +0 < . 1:1(0) ack 1 win 100
+   +0 accept(3, ..., ...) = 4
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) == 0, tcpi_options }%
+   +0 close(3) = 0

tools/testing/selftests/net/packetdrill/tcp_fastopen_server_basic-rw.pkt

@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Basic TFO server test
+//
+// Test TFO server with SYN that has TFO cookie and data.
+
+`./defaults.sh`
+
+    0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
+   +0 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, [1], 4) = 0
+
+   +0 < S 0:10(10) win 32792 <mss 1460,sackOK,nop,nop,FO TFO_COOKIE,nop,nop>
+   +0 > S. 0:0(0) ack 11 <mss 1460,nop,nop,sackOK>
+
+   +0 accept(3, ..., ...) = 4
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) != 0, tcpi_options }%
+
+   +0 read(4, ..., 512) = 10
+   +0 write(4, ..., 100) = 100
+   +0 > P. 1:101(100) ack 11

tools/testing/selftests/net/packetdrill/tcp_fastopen_server_basic-zero-payload.pkt

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Basic TFO server test
+//
+// Test zero-payload packet w/ valid TFO cookie - a TFO socket will
+// still be created and accepted but read() will not return until a
+// later pkt with 10 byte.
+
+`./defaults.sh`
+
+    0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
+   +0 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, [1], 4) = 0
+
+   +0 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,FO TFO_COOKIE,nop,nop>
+   +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK>
+   +0 accept(3, ..., ...) = 4
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) == 0, tcpi_options }%
+
+// A TFO socket is created and is writable.
+   +0 write(4, ..., 100) = 100
+   +0 > P. 1:101(100) ack 1
+   +0...0.300 read(4, ..., 512) = 10
+  +.3 < P. 1:11(10) ack 1 win 5840