[PATCH 07/33] net: add sock_bindtoindex

Christoph Hellwig
2020-05-20T20:00:42Z

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/net/sock.h | 1 +
net/core/sock.c | 21 +++++++++++++++------
net/ipv4/udp_tunnel.c | 4 +---
net/ipv6/ip6_udp_tunnel.c | 4 +---
4 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 9a7b9e98685ac..cdec7bc055d5b 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2688,6 +2688,7 @@ static inline bool sk_dev_equal_l3scope(struct sock *sk, int dif)

void sock_def_readable(struct sock *sk);

+int sock_bindtoindex(struct sock *sk, int ifindex);
void sock_no_linger(struct sock *sk);
void sock_set_priority(struct sock *sk, u32 priority);
void sock_set_reuseaddr(struct sock *sk);
diff --git a/net/core/sock.c b/net/core/sock.c
index d3b1d61e4f768..23f80880fbb2c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -566,7 +566,7 @@ struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie)
}
EXPORT_SYMBOL(sk_dst_check);

-static int sock_setbindtodevice_locked(struct sock *sk, int ifindex)
+static int sock_bindtoindex_locked(struct sock *sk, int ifindex)
{
int ret = -ENOPROTOOPT;
#ifdef CONFIG_NETDEVICES
@@ -594,6 +594,18 @@ static int sock_setbindtodevice_locked(struct sock *sk, int ifindex)
return ret;
}

+int sock_bindtoindex(struct sock *sk, int ifindex)
+{
+ int ret;
+
+ lock_sock(sk);
+ ret = sock_bindtoindex_locked(sk, ifindex);
+ release_sock(sk);
+
+ return ret;
+}
+EXPORT_SYMBOL(sock_bindtoindex);
+
static int sock_setbindtodevice(struct sock *sk, char __user *optval,
int optlen)
{
@@ -634,10 +646,7 @@ static int sock_setbindtodevice(struct sock *sk, char __user *optval,
goto out;
}

- lock_sock(sk);
- ret = sock_setbindtodevice_locked(sk, index);
- release_sock(sk);
-
+ return sock_bindtoindex(sk, index);
out:
#endif

@@ -1216,7 +1225,7 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
break;

case SO_BINDTOIFINDEX:
- ret = sock_setbindtodevice_locked(sk, val);
+ ret = sock_bindtoindex_locked(sk, val);
break;

default:
diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
index 150e6f0fdbf59..2158e8bddf41c 100644
--- a/net/ipv4/udp_tunnel.c
+++ b/net/ipv4/udp_tunnel.c
@@ -22,9 +22,7 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
goto error;

if (cfg->bind_ifindex) {
- err = kernel_setsockopt(sock, SOL_SOCKET, SO_BINDTOIFINDEX,
- (void *)&cfg->bind_ifindex,
- sizeof(cfg->bind_ifindex));
+ err = sock_bindtoindex(sock->sk, cfg->bind_ifindex);
if (err < 0)
goto error;
}
diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
index 58956a6b66a21..6523609516d25 100644
--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -33,9 +33,7 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
goto error;
}
if (cfg->bind_ifindex) {
- err = kernel_setsockopt(sock, SOL_SOCKET, SO_BINDTOIFINDEX,
- (void *)&cfg->bind_ifindex,
- sizeof(cfg->bind_ifindex));
+ err = sock_bindtoindex(sock->sk, cfg->bind_ifindex);
if (err < 0)
goto error;
}
--
2.26.2