bpf: add dsack_dups/delivered{, _ce} to bpf_tcp_sock

Add more fields to bpf_tcp_sock that might be useful for debugging
congestion control issues.

Cc: Eric Dumazet <edumazet@google.com>
Cc: Priyaranjan Jha <priyarjha@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

include/uapi/linux/bpf.h

@@ -3073,6 +3073,11 @@ struct bpf_tcp_sock {
 				 * sum(delta(snd_una)), or how many bytes
 				 * were acked.
 				 */
+	__u32 dsack_dups;	/* RFC4898 tcpEStatsStackDSACKDups
+				 * total number of DSACK blocks received
+				 */
+	__u32 delivered;	/* Total data packets delivered incl. rexmits */
+	__u32 delivered_ce;	/* Like the above but only ECE marked packets */
 };
 
 struct bpf_sock_tuple {

net/core/filter.c

@@ -5544,7 +5544,7 @@ static const struct bpf_func_proto bpf_sock_addr_sk_lookup_udp_proto = {
 bool bpf_tcp_sock_is_valid_access(int off, int size, enum bpf_access_type type,
 				  struct bpf_insn_access_aux *info)
 {
-	if (off < 0 || off >= offsetofend(struct bpf_tcp_sock, bytes_acked))
+	if (off < 0 || off >= offsetofend(struct bpf_tcp_sock, delivered_ce))
 		return false;
 
 	if (off % size != 0)
@@ -5652,6 +5652,15 @@ u32 bpf_tcp_sock_convert_ctx_access(enum bpf_access_type type,
 	case offsetof(struct bpf_tcp_sock, bytes_acked):
 		BPF_TCP_SOCK_GET_COMMON(bytes_acked);
 		break;
+	case offsetof(struct bpf_tcp_sock, dsack_dups):
+		BPF_TCP_SOCK_GET_COMMON(dsack_dups);
+		break;
+	case offsetof(struct bpf_tcp_sock, delivered):
+		BPF_TCP_SOCK_GET_COMMON(delivered);
+		break;
+	case offsetof(struct bpf_tcp_sock, delivered_ce):
+		BPF_TCP_SOCK_GET_COMMON(delivered_ce);
+		break;
 	}
 
 	return insn - insn_buf;