soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF

Expose socket options for setting a classic or extended BPF program
for use when selecting sockets in an SO_REUSEPORT group.  These options
can be used on the first socket to belong to a group before bind or
on any socket in the group after bind.

This change includes refactoring of the existing sk_filter code to
allow reuse of the existing BPF filter validation checks.

Signed-off-by: Craig Gallek <kraig@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 29 insertions, 0 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index 565bab7..5127023 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -134,6 +134,7 @@
 #include <linux/sock_diag.h>
 
 #include <linux/filter.h>
+#include <net/sock_reuseport.h>
 
 #include <trace/events/sock.h>
 
@@ -932,6 +933,32 @@ set_rcvbuf:
 		}
 		break;
 
+	case SO_ATTACH_REUSEPORT_CBPF:
+		ret = -EINVAL;
+		if (optlen == sizeof(struct sock_fprog)) {
+			struct sock_fprog fprog;
+
+			ret = -EFAULT;
+			if (copy_from_user(&fprog, optval, sizeof(fprog)))
+				break;
+
+			ret = sk_reuseport_attach_filter(&fprog, sk);
+		}
+		break;
+
+	case SO_ATTACH_REUSEPORT_EBPF:
+		ret = -EINVAL;
+		if (optlen == sizeof(u32)) {
+			u32 ufd;
+
+			ret = -EFAULT;
+			if (copy_from_user(&ufd, optval, sizeof(ufd)))
+				break;
+
+			ret = sk_reuseport_attach_bpf(ufd, sk);
+		}
+		break;
+
 	case SO_DETACH_FILTER:
 		ret = sk_detach_filter(sk);
 		break;
@@ -1443,6 +1470,8 @@ void sk_destruct(struct sock *sk)
 		sk_filter_uncharge(sk, filter);
 		RCU_INIT_POINTER(sk->sk_filter, NULL);
 	}
+	if (rcu_access_pointer(sk->sk_reuseport_cb))
+		reuseport_detach_sock(sk);
 
 	sock_disable_timestamp(sk, SK_FLAGS_TIMESTAMP);