bpf: sockmap, add hash map support

Sockmap is currently backed by an array and enforces keys to be
four bytes. This works well for many use cases and was originally
modeled after devmap which also uses four bytes keys. However,
this has become limiting in larger use cases where a hash would
be more appropriate. For example users may want to use the 5-tuple
of the socket as the lookup key.

To support this add hash support.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 58 insertions, 0 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index 61a3ed6bac25..6d0d1560bd70 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2074,6 +2074,33 @@ static const struct bpf_func_proto bpf_redirect_proto = {
 	.arg2_type      = ARG_ANYTHING,
 };
 
+BPF_CALL_4(bpf_sk_redirect_hash, struct sk_buff *, skb,
+	   struct bpf_map *, map, void *, key, u64, flags)
+{
+	struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
+
+	/* If user passes invalid input drop the packet. */
+	if (unlikely(flags & ~(BPF_F_INGRESS)))
+		return SK_DROP;
+
+	tcb->bpf.flags = flags;
+	tcb->bpf.sk_redir = __sock_hash_lookup_elem(map, key);
+	if (!tcb->bpf.sk_redir)
+		return SK_DROP;
+
+	return SK_PASS;
+}
+
+static const struct bpf_func_proto bpf_sk_redirect_hash_proto = {
+	.func           = bpf_sk_redirect_hash,
+	.gpl_only       = false,
+	.ret_type       = RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type      = ARG_CONST_MAP_PTR,
+	.arg3_type      = ARG_PTR_TO_MAP_KEY,
+	.arg4_type      = ARG_ANYTHING,
+};
+
 BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb,
 	   struct bpf_map *, map, u32, key, u64, flags)
 {
@@ -2108,6 +2135,31 @@ static const struct bpf_func_proto bpf_sk_redirect_map_proto = {
 	.arg4_type      = ARG_ANYTHING,
 };
 
+BPF_CALL_4(bpf_msg_redirect_hash, struct sk_msg_buff *, msg,
+	   struct bpf_map *, map, void *, key, u64, flags)
+{
+	/* If user passes invalid input drop the packet. */
+	if (unlikely(flags & ~(BPF_F_INGRESS)))
+		return SK_DROP;
+
+	msg->flags = flags;
+	msg->sk_redir = __sock_hash_lookup_elem(map, key);
+	if (!msg->sk_redir)
+		return SK_DROP;
+
+	return SK_PASS;
+}
+
+static const struct bpf_func_proto bpf_msg_redirect_hash_proto = {
+	.func           = bpf_msg_redirect_hash,
+	.gpl_only       = false,
+	.ret_type       = RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type      = ARG_CONST_MAP_PTR,
+	.arg3_type      = ARG_PTR_TO_MAP_KEY,
+	.arg4_type      = ARG_ANYTHING,
+};
+
 BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg_buff *, msg,
 	   struct bpf_map *, map, u32, key, u64, flags)
 {
@@ -4502,6 +4554,8 @@ sock_ops_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_sock_ops_cb_flags_set_proto;
 	case BPF_FUNC_sock_map_update:
 		return &bpf_sock_map_update_proto;
+	case BPF_FUNC_sock_hash_update:
+		return &bpf_sock_hash_update_proto;
 	default:
 		return bpf_base_func_proto(func_id);
 	}
@@ -4513,6 +4567,8 @@ sk_msg_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	switch (func_id) {
 	case BPF_FUNC_msg_redirect_map:
 		return &bpf_msg_redirect_map_proto;
+	case BPF_FUNC_msg_redirect_hash:
+		return &bpf_msg_redirect_hash_proto;
 	case BPF_FUNC_msg_apply_bytes:
 		return &bpf_msg_apply_bytes_proto;
 	case BPF_FUNC_msg_cork_bytes:
@@ -4544,6 +4600,8 @@ sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_get_socket_uid_proto;
 	case BPF_FUNC_sk_redirect_map:
 		return &bpf_sk_redirect_map_proto;
+	case BPF_FUNC_sk_redirect_hash:
+		return &bpf_sk_redirect_hash_proto;
 	default:
 		return bpf_base_func_proto(func_id);
 	}