[PATCH 17/33] tcp: add tcp_sock_set_keepidle

Christoph Hellwig
2020-05-20T19:56:39Z

Add a helper to directly set the TCP_KEEP_IDLE sockopt from kernel
space without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/linux/tcp.h | 1 +
net/ipv4/tcp.c | 49 ++++++++++++++++++++++++++++++-------------
net/rds/tcp_listen.c | 5 +----
net/sunrpc/xprtsock.c | 3 +--
4 files changed, 37 insertions(+), 21 deletions(-)

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index de682143efe4d..5724dd84a85ed 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -498,6 +498,7 @@ int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
int shiftlen);

void tcp_sock_set_cork(struct sock *sk, bool on);
+int tcp_sock_set_keepidle(struct sock *sk, int val);
void tcp_sock_set_nodelay(struct sock *sk);
void tcp_sock_set_quickack(struct sock *sk, int val);
int tcp_sock_set_syncnt(struct sock *sk, int val);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 0004bd9ae7b0a..bdf0ff9333514 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2901,6 +2901,39 @@ void tcp_sock_set_user_timeout(struct sock *sk, u32 val)
}
EXPORT_SYMBOL(tcp_sock_set_user_timeout);

+static int __tcp_sock_set_keepidle(struct sock *sk, int val)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if (val < 1 || val > MAX_TCP_KEEPIDLE)
+ return -EINVAL;
+
+ tp->keepalive_time = val * HZ;
+ if (sock_flag(sk, SOCK_KEEPOPEN) &&
+ !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
+ u32 elapsed = keepalive_time_elapsed(tp);
+
+ if (tp->keepalive_time > elapsed)
+ elapsed = tp->keepalive_time - elapsed;
+ else
+ elapsed = 0;
+ inet_csk_reset_keepalive_timer(sk, elapsed);
+ }
+
+ return 0;
+}
+
+int tcp_sock_set_keepidle(struct sock *sk, int val)
+{
+ int err;
+
+ lock_sock(sk);
+ err = __tcp_sock_set_keepidle(sk, val);
+ release_sock(sk);
+ return err;
+}
+EXPORT_SYMBOL(tcp_sock_set_keepidle);
+
/*
* Socket option code for TCP.
*/
@@ -3070,21 +3103,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
break;

case TCP_KEEPIDLE:
- if (val < 1 || val > MAX_TCP_KEEPIDLE)
- err = -EINVAL;
- else {
- tp->keepalive_time = val * HZ;
- if (sock_flag(sk, SOCK_KEEPOPEN) &&
- !((1 << sk->sk_state) &
- (TCPF_CLOSE | TCPF_LISTEN))) {
- u32 elapsed = keepalive_time_elapsed(tp);
- if (tp->keepalive_time > elapsed)
- elapsed = tp->keepalive_time - elapsed;
- else
- elapsed = 0;
- inet_csk_reset_keepalive_timer(sk, elapsed);
- }
- }
+ err = __tcp_sock_set_keepidle(sk, val);
break;
case TCP_KEEPINTVL:
if (val < 1 || val > MAX_TCP_KEEPINTVL)
diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
index 6f90ea077adcd..79f9adc008114 100644
--- a/net/rds/tcp_listen.c
+++ b/net/rds/tcp_listen.c
@@ -52,10 +52,7 @@ int rds_tcp_keepalive(struct socket *sock)
if (ret < 0)
goto bail;

- ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPIDLE,
- (char *)&keepidle, sizeof(keepidle));
- if (ret < 0)
- goto bail;
+ tcp_sock_set_keepidle(sock->sk, keepidle);

/* KEEPINTVL is the interval between successive probes. We follow
* the model in xs_tcp_finish_connecting() and re-use keepidle.
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 231fd6162f68d..473290f7c5c0a 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2107,8 +2107,7 @@ static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,

/* TCP Keepalive options */
sock_set_keepalive(sock->sk);
- kernel_setsockopt(sock, SOL_TCP, TCP_KEEPIDLE,
- (char *)&keepidle, sizeof(keepidle));
+ tcp_sock_set_keepidle(sock->sk, keepidle);
kernel_setsockopt(sock, SOL_TCP, TCP_KEEPINTVL,
(char *)&keepidle, sizeof(keepidle));
kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT,
--
2.26.2