[PATCH bpf-next v2 3/3] bpf: add SO_KEEPALIVE and related options to bpf_setsockopt

[Dmitry Yakunin <zeil@xxxxxxxxxxxxxx>]

This patch adds support of SO_KEEPALIVE flag and TCP related options
to bpf_setsockopt() routine. This is helpful if we want to enable or tune
TCP keepalive for applications which don't do it in the userspace code.

Signed-off-by: Dmitry Yakunin <zeil@xxxxxxxxxxxxxx>
Acked-by: Martin KaFai Lau <kafai@xxxxxx>
---
 net/core/filter.c | 39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index a6fc234..f125f9d 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4248,8 +4248,8 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = {
 static int _bpf_setsockopt(struct sock *sk, int level, int optname,
 			   char *optval, int optlen, u32 flags)
 {
+	int val, valbool;
 	int ret = 0;
-	int val;
 
 	if (!sk_fullsock(sk))
 		return -EINVAL;
@@ -4260,6 +4260,7 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
 		if (optlen != sizeof(int))
 			return -EINVAL;
 		val = *((int *)optval);
+		valbool = val ? 1 : 0;
 
 		/* Only some socketops are supported */
 		switch (optname) {
@@ -4298,6 +4299,11 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
 				sk_dst_reset(sk);
 			}
 			break;
+		case SO_KEEPALIVE:
+			if (sk->sk_prot->keepalive)
+				sk->sk_prot->keepalive(sk, valbool);
+			sock_valbool_flag(sk, SOCK_KEEPOPEN, valbool);
+			break;
 		default:
 			ret = -EINVAL;
 		}
@@ -4358,6 +4364,7 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
 			ret = tcp_set_congestion_control(sk, name, false,
 							 reinit, true);
 		} else {
+			struct inet_connection_sock *icsk = inet_csk(sk);
 			struct tcp_sock *tp = tcp_sk(sk);
 
 			if (optlen != sizeof(int))
@@ -4386,6 +4393,36 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
 				else
 					tp->save_syn = val;
 				break;
+			case TCP_KEEPIDLE:
+				if (val < 1 || val > MAX_TCP_KEEPIDLE)
+					ret = -EINVAL;
+				else
+					keepalive_time_set(sk, val);
+				break;
+			case TCP_KEEPINTVL:
+				if (val < 1 || val > MAX_TCP_KEEPINTVL)
+					ret = -EINVAL;
+				else
+					tp->keepalive_intvl = val * HZ;
+				break;
+			case TCP_KEEPCNT:
+				if (val < 1 || val > MAX_TCP_KEEPCNT)
+					ret = -EINVAL;
+				else
+					tp->keepalive_probes = val;
+				break;
+			case TCP_SYNCNT:
+				if (val < 1 || val > MAX_TCP_SYNCNT)
+					ret = -EINVAL;
+				else
+					icsk->icsk_syn_retries = val;
+				break;
+			case TCP_USER_TIMEOUT:
+				if (val < 0)
+					ret = -EINVAL;
+				else
+					icsk->icsk_user_timeout = val;
+				break;
 			default:
 				ret = -EINVAL;
 			}
-- 
2.7.4