Merge branch 'Align BPF TCP CCs implementing cong_control() with non-BPF CCs'

Jörn-Thorben Hinz says:

====================

This series corrects some inconveniences for a BPF TCP CC that
implements and uses tcp_congestion_ops.cong_control(). Until now, such a
CC did not have all necessary write access to struct sock and
unnecessarily needed to implement cong_avoid().

v4:
 - Remove braces around single statements after if
 - Don’t check pointer passed to bpf_link__destroy()
v3:
 - Add a selftest writing sk_pacing_*
 - Add a selftest with incomplete tcp_congestion_ops
 - Add a selftest with unsupported get_info()
 - Remove an unused variable
 - Reword a comment about reg() in bpf_struct_ops_map_update_elem()
v2:
 - Drop redundant check for required functions and just rely on
   tcp_register_congestion_control() (Martin KaFai Lau)
====================

Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 6 insertions, 33 deletions

diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index f79ab942f03b..7a181631b995 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -14,18 +14,6 @@
 /* "extern" is to avoid sparse warning.  It is only used in bpf_struct_ops.c. */
 extern struct bpf_struct_ops bpf_tcp_congestion_ops;
 
-static u32 optional_ops[] = {
-	offsetof(struct tcp_congestion_ops, init),
-	offsetof(struct tcp_congestion_ops, release),
-	offsetof(struct tcp_congestion_ops, set_state),
-	offsetof(struct tcp_congestion_ops, cwnd_event),
-	offsetof(struct tcp_congestion_ops, in_ack_event),
-	offsetof(struct tcp_congestion_ops, pkts_acked),
-	offsetof(struct tcp_congestion_ops, min_tso_segs),
-	offsetof(struct tcp_congestion_ops, sndbuf_expand),
-	offsetof(struct tcp_congestion_ops, cong_control),
-};
-
 static u32 unsupported_ops[] = {
 	offsetof(struct tcp_congestion_ops, get_info),
 };
@@ -51,18 +39,6 @@ static int bpf_tcp_ca_init(struct btf *btf)
 	return 0;
 }
 
-static bool is_optional(u32 member_offset)
-{
-	unsigned int i;
-
-	for (i = 0; i < ARRAY_SIZE(optional_ops); i++) {
-		if (member_offset == optional_ops[i])
-			return true;
-	}
-
-	return false;
-}
-
 static bool is_unsupported(u32 member_offset)
 {
 	unsigned int i;
@@ -111,6 +87,12 @@ static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log,
 	}
 
 	switch (off) {
+	case offsetof(struct sock, sk_pacing_rate):
+		end = offsetofend(struct sock, sk_pacing_rate);
+		break;
+	case offsetof(struct sock, sk_pacing_status):
+		end = offsetofend(struct sock, sk_pacing_status);
+		break;
 	case bpf_ctx_range(struct inet_connection_sock, icsk_ca_priv):
 		end = offsetofend(struct inet_connection_sock, icsk_ca_priv);
 		break;
@@ -240,7 +222,6 @@ static int bpf_tcp_ca_init_member(const struct btf_type *t,
 {
 	const struct tcp_congestion_ops *utcp_ca;
 	struct tcp_congestion_ops *tcp_ca;
-	int prog_fd;
 	u32 moff;
 
 	utcp_ca = (const struct tcp_congestion_ops *)udata;
@@ -262,14 +243,6 @@ static int bpf_tcp_ca_init_member(const struct btf_type *t,
 		return 1;
 	}
 
-	if (!btf_type_resolve_func_ptr(btf_vmlinux, member->type, NULL))
-		return 0;
-
-	/* Ensure bpf_prog is provided for compulsory func ptr */
-	prog_fd = (int)(*(unsigned long *)(udata + moff));
-	if (!prog_fd && !is_optional(moff) && !is_unsupported(moff))
-		return -EINVAL;
-
 	return 0;
 }