[PATCH 21/33] ipv4: add ip_sock_set_freebind

Christoph Hellwig
2020-05-20T19:58:48Z

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/target/iscsi/iscsi_target_login.c | 13 +++----------
include/net/ip.h | 1 +
net/ipv4/ip_sockglue.c | 8 ++++++++
3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index b561b07a869a0..85748e3388582 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -15,6 +15,7 @@
#include <linux/sched/signal.h>
#include <linux/idr.h>
#include <linux/tcp.h> /* TCP_NODELAY */
+#include <net/ip.h>
#include <net/ipv6.h> /* ipv6_addr_v4mapped() */
#include <scsi/iscsi_proto.h>
#include <target/target_core_base.h>
@@ -855,7 +856,7 @@ int iscsit_setup_np(
struct sockaddr_storage *sockaddr)
{
struct socket *sock = NULL;
- int backlog = ISCSIT_TCP_BACKLOG, ret, opt = 0, len;
+ int backlog = ISCSIT_TCP_BACKLOG, ret, len;

switch (np->np_network_transport) {
case ISCSI_TCP:
@@ -900,15 +901,7 @@ int iscsit_setup_np(
if (np->np_network_transport == ISCSI_TCP)
tcp_sock_set_nodelay(sock->sk);
sock_set_reuseaddr(sock->sk);
-
- opt = 1;
- ret = kernel_setsockopt(sock, IPPROTO_IP, IP_FREEBIND,
- (char *)&opt, sizeof(opt));
- if (ret < 0) {
- pr_err("kernel_setsockopt() for IP_FREEBIND"
- " failed\n");
- goto fail;
- }
+ ip_sock_set_freebind(sock->sk);

ret = kernel_bind(sock, (struct sockaddr *)&np->np_sockaddr, len);
if (ret < 0) {
diff --git a/include/net/ip.h b/include/net/ip.h
index 2fc52e26fa88b..5f5d8226b6abc 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -765,6 +765,7 @@ static inline bool inetdev_valid_mtu(unsigned int mtu)
return likely(mtu >= IPV4_MIN_MTU);
}

+void ip_sock_set_freebind(struct sock *sk);
void ip_sock_set_tos(struct sock *sk, int val);

#endif /* _IP_H */
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 1733ac78c21aa..62e642ab80126 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -581,6 +581,14 @@ void ip_sock_set_tos(struct sock *sk, int val)
}
EXPORT_SYMBOL(ip_sock_set_tos);

+void ip_sock_set_freebind(struct sock *sk)
+{
+ lock_sock(sk);
+ inet_sk(sk)->freebind = true;
+ release_sock(sk);
+}
+EXPORT_SYMBOL(ip_sock_set_freebind);
+
/*
* Socket option code for IP. This is the end of the line after any
* TCP,UDP etc options on an IP socket.
--
2.26.2