selftest: packetdrill: Import sockopt-fastopen-key.pkt

sockopt-fastopen-key.pkt does not have the non-experimental
version, so the Experimental version is converted, FOEXP -> FO.

The test sets net.ipv4.tcp_fastopen_key=0-0-0-0 and instead
sets another key via setsockopt(TCP_FASTOPEN_KEY).

The first listener generates a valid cookie in response to TFO
option without cookie, and the second listner creates a TFO socket
using the valid cookie.

TCP_FASTOPEN_KEY is adjusted to use the common key in default.sh
so that we can use TFO_COOKIE and support dualstack.  Similarly,
TFO_COOKIE_ZERO for the 0-0-0-0 key is defined.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250927213022.1850048-13-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: q2ven

tools/testing/selftests/net/packetdrill/ksft_runner.sh

@@ -10,6 +10,7 @@ declare -A ip_args=(
 		--netmask_ip=255.255.0.0
 		--remote_ip=192.0.2.1
 		-D TFO_COOKIE=3021b9d889017eeb
+		-D TFO_COOKIE_ZERO=b7c12350a90dc8f5
 		-D CMSG_LEVEL_IP=SOL_IP
 		-D CMSG_TYPE_RECVERR=IP_RECVERR"
 	[ipv6]="--ip_version=ipv6
@@ -18,6 +19,7 @@ declare -A ip_args=(
 		--gateway_ip=fd3d:0a0b:17d6:8888::1
 		--remote_ip=fd3d:fa7b:d17d::1
 		-D TFO_COOKIE=c1d1e9742a47a9bc
+		-D TFO_COOKIE_ZERO=82af1a8f9a205c34
 		-D CMSG_LEVEL_IP=SOL_IPV6
 		-D CMSG_TYPE_RECVERR=IPV6_RECVERR"
 )

tools/testing/selftests/net/packetdrill/tcp_fastopen_server_sockopt-fastopen-key.pkt

@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Test the server cookie is generated by aes64 encoding of remote and local
+// IP addresses with a master key specified via sockopt TCP_FASTOPEN_KEY
+//
+`./defaults.sh
+ ./set_sysctls.py /proc/sys/net/ipv4/tcp_fastopen_key=00000000-00000000-00000000-00000000`
+
+    0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
+   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
+
+// Set a key of a1a1a1a1-b2b2b2b2-c3c3c3c3-d4d4d4d4 (big endian).
+// This would produce a cookie of TFO_COOKIE like many other
+// tests (which the same key but set via sysctl).
+   +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN_KEY,
+                 "\xa1\xa1\xa1\xa1\xb2\xb2\xb2\xb2\xc3\xc3\xc3\xc3\xd4\xd4\xd4\xd4", 16) = 0
+
+   +0 bind(3, ..., ...) = 0
+   +0 listen(3, 1) = 0
+   +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN, [1], 4) = 0
+
+// Request a valid cookie TFO_COOKIE
+   +0 < S 1428932:1428942(10) win 10000 <mss 1012,nop,nop,FO,sackOK,TS val 1 ecr 0,nop,wscale 7>
+   +0 > S. 0:0(0) ack 1428933 <mss 1460,sackOK,TS val 10000 ecr 1,nop,wscale 8,FO TFO_COOKIE,nop,nop>
+   +0 < . 1:1(0) ack 1 win 257 <nop,nop,TS val 2 ecr 10000>
+   +0 accept(3, ..., ...) = 4
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) == 0, tcpi_options }%
+
+   +0 close(4) = 0
+   +0 > F. 1:1(0) ack 1 <nop,nop,TS val 10001 ecr 2>
+   +0 < F. 1:1(0) ack 2 win 257 <nop,nop,TS val 3 ecr 10001>
+   +0 > . 2:2(0) ack 2 <nop,nop,TS val 10002 ecr 3>
+
+   +0 close(3) = 0
+
+// Restart the listener
+   +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
+
+// Test setting the key in the listen state, and produces an identical cookie
+   +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN_KEY,
+                 "\xa1\xa1\xa1\xa1\xb2\xb2\xb2\xb2\xc3\xc3\xc3\xc3\xd4\xd4\xd4\xd4", 16) = 0
+
+   +0 < S 6814000:6815000(1000) win 10000 <mss 1012,nop,nop,FO TFO_COOKIE,sackOK,TS val 10 ecr 0,nop,wscale 7>
+   +0 > S. 0:0(0) ack 6815001 <mss 1460,sackOK,TS val 10000 ecr 10,nop,wscale 8>
+   +0 accept(3, ..., ...) = 4
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) != 0, tcpi_options }%
+   +0 < . 1001:1001(0) ack 1 win 257 <nop,nop,TS val 12 ecr 10000>
+   +0 read(4, ..., 8192) = 1000
+
+   +0 close(4) = 0
+   +0 > F. 1:1(0) ack 1001 <nop,nop,TS val 10101 ecr 12>
+   +0 < F. 1001:1001(0) ack 2 win 257 <nop,nop,TS val 112 ecr 10101>
+   +0 > . 2:2(0) ack 1002 <nop,nop,TS val 10102 ecr 112>
+
+   +0 close(3) = 0
+
+// Restart the listener
+   +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
+
+// Test invalid key length (must be 16 bytes)
+   +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN_KEY, "", 0) = -1 (Invalid Argument)
+   +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN_KEY, "", 3) = -1 (Invalid Argument)
+
+// Previous cookie won't be accepted b/c this listener uses the global key (0-0-0-0)
+   +0 < S 6814000:6815000(1000) win 10000 <mss 1012,nop,nop,FO TFO_COOKIE,sackOK,TS val 10 ecr 0,nop,wscale 7>
+   +0 > S. 0:0(0) ack 6814001 <mss 1460,sackOK,TS val 10000 ecr 10,nop,wscale 8,FO TFO_COOKIE_ZERO,nop,nop>