[PATCH 01/13] bpf: Enable retrieval of socket cookie for bind/post-bind hook

[Khalid Elmously]

From: Daniel Borkmann <daniel at iogearbox.net>

BugLink: https://bugs.launchpad.net/bugs/1887740

[ upstream commit 0e53d9e5e82056555020c47ee0c7a087147be084 ]

We currently make heavy use of the socket cookie in BPF's connect(),
sendmsg() and recvmsg() hooks for load-balancing decisions. However,
it is currently not enabled/implemented in BPF {post-}bind hooks
where it can later be used in combination for correlation in the tc
egress path, for example.

Signed-off-by: Daniel Borkmann <daniel at iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast at kernel.org>
Link: https://lore.kernel.org/bpf/e9d71f310715332f12d238cc650c1edc5be55119.1585323121.git.daniel@iogearbox.net
Signed-off-by: Daniel Borkmann <daniel at iogearbox.net>
Signed-off-by: Khalid Elmously <khalid.elmously at canonical.com>
---
 net/core/filter.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index f1f2304822e3..d6f781e0a894 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4184,6 +4184,18 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_addr_proto = {
 	.arg1_type	= ARG_PTR_TO_CTX,
 };
 
+BPF_CALL_1(bpf_get_socket_cookie_sock, struct sock *, ctx)
+{
+	return sock_gen_cookie(ctx);
+}
+
+static const struct bpf_func_proto bpf_get_socket_cookie_sock_proto = {
+	.func		= bpf_get_socket_cookie_sock,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
 BPF_CALL_1(bpf_get_socket_cookie_sock_ops, struct bpf_sock_ops_kern *, ctx)
 {
 	return sock_gen_cookie(ctx->sk);
@@ -6019,6 +6031,8 @@ sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_get_current_uid_gid_proto;
 	case BPF_FUNC_get_local_storage:
 		return &bpf_get_local_storage_proto;
+	case BPF_FUNC_get_socket_cookie:
+		return &bpf_get_socket_cookie_sock_proto;
 	default:
 		return bpf_base_func_proto(func_id);
 	}
-- 
2.17.1