Re: [PATCH bpf-next v6 07/11] bpf: Add support for reading sk_state and more

Add support for reading many more tcp_sock fields

  state,	same as sk->sk_state
  rtt_min	same as sk->rtt_min.s[0].v (current rtt_min)
  snd_ssthresh
  rcv_nxt
  snd_nxt
  snd_una
  mss_cache
  ecn_flags
  rate_delivered
  rate_interval_us
  packets_out
  retrans_out
  total_retrans
  segs_in
  data_segs_in
  segs_out
  data_segs_out
  bytes_received (__u64)
  bytes_acked    (__u64)

Signed-off-by: Lawrence Brakmo <redacted>
---
 include/uapi/linux/bpf.h |  19 +++++++
 net/core/filter.c        | 134 ++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 140 insertions(+), 13 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 2a8c40a..ff34f3c 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h

@@ -979,6 +979,25 @@ struct bpf_sock_ops {
 	__u32 snd_cwnd;
 	__u32 srtt_us;		/* Averaged RTT << 3 in usecs */
 	__u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
+	__u32 state;
+	__u32 rtt_min;
+	__u32 snd_ssthresh;
+	__u32 rcv_nxt;
+	__u32 snd_nxt;
+	__u32 snd_una;
+	__u32 mss_cache;
+	__u32 ecn_flags;
+	__u32 rate_delivered;
+	__u32 rate_interval_us;
+	__u32 packets_out;
+	__u32 retrans_out;
+	__u32 total_retrans;
+	__u32 segs_in;
+	__u32 data_segs_in;
+	__u32 segs_out;
+	__u32 data_segs_out;

+	__u64 bytes_received;
+	__u64 bytes_acked;
 };
 
 /* List of known BPF sock_ops operators.

diff --git a/net/core/filter.c b/net/core/filter.c
index c9411dc..98665ba 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c

@@ -3849,34 +3849,43 @@ void bpf_warn_invalid_xdp_action(u32 act)
 }
 EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action);
 
-static bool __is_valid_sock_ops_access(int off, int size)
+static bool sock_ops_is_valid_access(int off, int size,
+				     enum bpf_access_type type,
+				     struct bpf_insn_access_aux *info)
 {
+	const int size_default = sizeof(__u32);
+
 	if (off < 0 || off >= sizeof(struct bpf_sock_ops))
 		return false;
+
 	/* The verifier guarantees that size > 0. */
 	if (off % size != 0)
 		return false;
-	if (size != sizeof(__u32))
-		return false;
-
-	return true;
-}
 
-static bool sock_ops_is_valid_access(int off, int size,
-				     enum bpf_access_type type,
-				     struct bpf_insn_access_aux *info)
-{
 	if (type == BPF_WRITE) {
 		switch (off) {
-		case offsetof(struct bpf_sock_ops, op) ...
-		     offsetof(struct bpf_sock_ops, replylong[3]):
+		case bpf_ctx_range_till(struct bpf_sock_ops, op, replylong[3]):
+			if (size != size_default)
+				return false;
 			break;
 		default:
 			return false;
 		}
+	} else {
+		switch (off) {
+		case bpf_ctx_range_till(struct bpf_sock_ops, bytes_received,
+					bytes_acked):
+			if (size != sizeof(__u64))
+				return false;
+			break;
+		default:
+			if (size != size_default)
+				return false;
+			break;
+		}
 	}
 
-	return __is_valid_sock_ops_access(off, size);
+	return true;
 }