net: Introduce netns_bpf for BPF programs attached to netns

In order to:

 (1) attach more than one BPF program type to netns, or
 (2) support attaching BPF programs to netns with bpf_link, or
 (3) support multi-prog attach points for netns

we will need to keep more state per netns than a single pointer like we
have now for BPF flow dissector program.

Prepare for the above by extracting netns_bpf that is part of struct net,
for storing all state related to BPF programs attached to netns.

Turn flow dissector callbacks for querying/attaching/detaching a program
into generic ones that operate on netns_bpf. Next patch will move the
generic callbacks into their own module.

This is similar to how it is organized for cgroup with cgroup_bpf.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20200531082846.2117903-3-jakub@cloudflare.com

1 files changed, 4 insertions, 3 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index e83b0818b529..c77ab9c76f7b 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -27,6 +27,7 @@
 #include <uapi/linux/btf.h>
 #include <linux/bpf_lsm.h>
 #include <linux/poll.h>
+#include <linux/bpf-netns.h>
 
 #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \
 			  (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \
@@ -2868,7 +2869,7 @@ static int bpf_prog_attach(const union bpf_attr *attr)
 		ret = lirc_prog_attach(attr, prog);
 		break;
 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
-		ret = skb_flow_dissector_bpf_prog_attach(attr, prog);
+		ret = netns_bpf_prog_attach(attr, prog);
 		break;
 	case BPF_PROG_TYPE_CGROUP_DEVICE:
 	case BPF_PROG_TYPE_CGROUP_SKB:
@@ -2908,7 +2909,7 @@ static int bpf_prog_detach(const union bpf_attr *attr)
 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
-		return skb_flow_dissector_bpf_prog_detach(attr);
+		return netns_bpf_prog_detach(attr);
 	case BPF_PROG_TYPE_CGROUP_DEVICE:
 	case BPF_PROG_TYPE_CGROUP_SKB:
 	case BPF_PROG_TYPE_CGROUP_SOCK:
@@ -2961,7 +2962,7 @@ static int bpf_prog_query(const union bpf_attr *attr,
 	case BPF_LIRC_MODE2:
 		return lirc_prog_query(attr, uattr);
 	case BPF_FLOW_DISSECTOR:
-		return skb_flow_dissector_prog_query(attr, uattr);
+		return netns_bpf_prog_query(attr, uattr);
 	default:
 		return -EINVAL;
 	}