[PATCH 22/33] ipv6: add ip6_sock_set_v6only

From: Christoph Hellwig
Date: Wed May 13 2020 - 02:29:04 EST


Add a helper to directly set the IPV6_V6ONLY sockopt from kernel space
without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
include/net/ipv6.h | 3 +++
net/ipv6/ip6_udp_tunnel.c | 5 +----
net/ipv6/ipv6_sockglue.c | 11 +++++++++++
net/sunrpc/svcsock.c | 8 ++------
4 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 955badd1e8ffc..e24b59201a00d 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -1174,4 +1174,7 @@ int ipv6_sock_mc_join_ssm(struct sock *sk, int ifindex,
const struct in6_addr *addr, unsigned int mode);
int ipv6_sock_mc_drop(struct sock *sk, int ifindex,
const struct in6_addr *addr);
+
+int ip6_sock_set_v6only(struct sock *sk, bool val);
+
#endif /* _NET_IPV6_H */
diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
index 6523609516d25..bc4ee5cb14c8b 100644
--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -25,10 +25,7 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
goto error;

if (cfg->ipv6_v6only) {
- int val = 1;
-
- err = kernel_setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY,
- (char *) &val, sizeof(val));
+ err = ip6_sock_set_v6only(sock->sk, true);
if (err < 0)
goto error;
}
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 18d05403d3b52..f26224bb3e098 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -136,6 +136,17 @@ static bool setsockopt_needs_rtnl(int optname)
return false;
}

+int ip6_sock_set_v6only(struct sock *sk, bool val)
+{
+ if (inet_sk(sk)->inet_num)
+ return -EINVAL;
+ lock_sock(sk);
+ sk->sk_ipv6only = val;
+ release_sock(sk);
+ return 0;
+}
+EXPORT_SYMBOL(ip6_sock_set_v6only);
+
static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen)
{
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 7a4f01c79e0f1..7fa7fedec3c5a 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -1328,7 +1328,6 @@ static struct svc_xprt *svc_create_socket(struct svc_serv *serv,
struct sockaddr *newsin = (struct sockaddr *)&addr;
int newlen;
int family;
- int val;
RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);

dprintk("svc: svc_create_socket(%s, %d, %s)\n",
@@ -1364,11 +1363,8 @@ static struct svc_xprt *svc_create_socket(struct svc_serv *serv,
* getting requests from IPv4 remotes. Those should
* be shunted to a PF_INET listener via rpcbind.
*/
- val = 1;
- if (family == PF_INET6)
- kernel_setsockopt(sock, SOL_IPV6, IPV6_V6ONLY,
- (char *)&val, sizeof(val));
-
+ if (family == PF_INET6 && IS_REACHABLE(CONFIG_IPV6))
+ ip6_sock_set_v6only(sock->sk, true);
if (type == SOCK_STREAM)
sock->sk->sk_reuse = SK_CAN_REUSE; /* allow address reuse */
error = kernel_bind(sock, sin, len);
--
2.26.2