[PATCH v2 net-next 2/3] bpf: Allow SO_BINDTODEVICE opt in bpf_setsockopt

Ferenc Fejes
2020-05-30T21:09:59Z

Extending the supported sockopts in bpf_setsockopt with
SO_BINDTODEVICE. We call sock_bindtoindex with parameter
lock_sk = false in this context because we already owning
the socket.

Signed-off-by: Ferenc Fejes <fejes@inf.elte.hu>
---
net/core/filter.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index bd2853d23b50..a0958c5ef127 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4248,6 +4248,9 @@ 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)
{
+ char devname[IFNAMSIZ];
+ struct net *net;
+ int ifindex;
int ret = 0;
int val;

@@ -4257,7 +4260,7 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
sock_owned_by_me(sk);

if (level == SOL_SOCKET) {
- if (optlen != sizeof(int))
+ if (optlen != sizeof(int) && optname != SO_BINDTODEVICE)
return -EINVAL;
val = *((int *)optval);

@@ -4298,6 +4301,29 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
sk_dst_reset(sk);
}
break;
+ case SO_BINDTODEVICE:
+ ret = -ENOPROTOOPT;
+#ifdef CONFIG_NETDEVICES
+ optlen = min_t(long, optlen, IFNAMSIZ - 1);
+ strncpy(devname, optval, optlen);
+ devname[optlen] = 0;
+
+ ifindex = 0;
+ if (devname[0] != '\0') {
+ struct net_device *dev;
+
+ ret = -ENODEV;
+
+ net = sock_net(sk);
+ dev = dev_get_by_name(net, devname);
+ if (!dev)
+ break;
+ ifindex = dev->ifindex;
+ dev_put(dev);
+ }
+ ret = sock_bindtoindex(sk, ifindex, false);
+#endif
+ break;
default:
ret = -EINVAL;
}
--
2.17.1