Merge branch 'bpf-support-setting-max-rto-for-bpf_setsockopt'

Jason Xing says:

====================
Support max RTO set by BPF program calling bpf_setsockopt().
Add corresponding selftests.
====================

Link: https://patch.msgid.link/20250219081333.56378-1-kerneljasonxing@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

net/core/filter.c

@@ -5382,6 +5382,7 @@ static int sol_tcp_sockopt(struct sock *sk, int optname,
 	case TCP_USER_TIMEOUT:
 	case TCP_NOTSENT_LOWAT:
 	case TCP_SAVE_SYN:
+	case TCP_RTO_MAX_MS:
 		if (*optlen != sizeof(int))
 			return -EINVAL;
 		break;

tools/testing/selftests/bpf/progs/bpf_tracing_net.h

@@ -49,6 +49,7 @@
 #define TCP_SAVED_SYN		28
 #define TCP_CA_NAME_MAX		16
 #define TCP_NAGLE_OFF		1
+#define TCP_RTO_MAX_MS		44
 
 #define TCP_ECN_OK              1
 #define TCP_ECN_QUEUE_CWR       2

tools/testing/selftests/bpf/progs/setget_sockopt.c

@@ -61,6 +61,7 @@ static const struct sockopt_test sol_tcp_tests[] = {
 	{ .opt = TCP_NOTSENT_LOWAT, .new = 1314, .expected = 1314, },
 	{ .opt = TCP_BPF_SOCK_OPS_CB_FLAGS, .new = BPF_SOCK_OPS_ALL_CB_FLAGS,
 	  .expected = BPF_SOCK_OPS_ALL_CB_FLAGS, },
+	{ .opt = TCP_RTO_MAX_MS, .new = 2000, .expected = 2000, },
 	{ .opt = 0, },
 };