Commit 44f0e430 authored by Lawrence Brakmo's avatar Lawrence Brakmo Committed by Alexei Starovoitov
Browse files

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
  lost_out
  sacked_out
  sk_txhash
  bytes_received (__u64)
  bytes_acked    (__u64)

Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f89013f6

include/uapi/linux/bpf.h

+22 −0
Original line number Diff line number Diff line
@@ -979,6 +979,28 @@ 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;

	__u32 lost_out;

	__u32 sacked_out;

	__u32 sk_txhash;

	__u64 bytes_received;

	__u64 bytes_acked;

};



/* Definitions for bpf_sock_ops_cb_flags */

net/core/filter.c

+132 −11
Original line number Diff line number Diff line
@@ -3855,33 +3855,43 @@ 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, reply):

			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;

}



static int sk_skb_prologue(struct bpf_insn *insn_buf, bool direct_write,
@@ -4498,6 +4508,32 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type, 
					       is_fullsock));

		break;



	case offsetof(struct bpf_sock_ops, state):

		BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_state) != 1);



		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

						struct bpf_sock_ops_kern, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct bpf_sock_ops_kern, sk));

		*insn++ = BPF_LDX_MEM(BPF_B, si->dst_reg, si->dst_reg,

				      offsetof(struct sock_common, skc_state));

		break;



	case offsetof(struct bpf_sock_ops, rtt_min):

		BUILD_BUG_ON(FIELD_SIZEOF(struct tcp_sock, rtt_min) !=

			     sizeof(struct minmax));

		BUILD_BUG_ON(sizeof(struct minmax) <

			     sizeof(struct minmax_sample));



		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(

						struct bpf_sock_ops_kern, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct bpf_sock_ops_kern, sk));

		*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,

				      offsetof(struct tcp_sock, rtt_min) +

				      FIELD_SIZEOF(struct minmax_sample, t));

		break;



/* Helper macro for adding read access to tcp_sock or sock fields. */

#define SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ)			      \

	do {								      \
@@ -4580,6 +4616,91 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type, 
		SOCK_OPS_GET_FIELD(bpf_sock_ops_cb_flags, bpf_sock_ops_cb_flags,

				   struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, snd_ssthresh):

		SOCK_OPS_GET_FIELD(snd_ssthresh, snd_ssthresh, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, rcv_nxt):

		SOCK_OPS_GET_FIELD(rcv_nxt, rcv_nxt, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, snd_nxt):

		SOCK_OPS_GET_FIELD(snd_nxt, snd_nxt, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, snd_una):

		SOCK_OPS_GET_FIELD(snd_una, snd_una, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, mss_cache):

		SOCK_OPS_GET_FIELD(mss_cache, mss_cache, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, ecn_flags):

		SOCK_OPS_GET_FIELD(ecn_flags, ecn_flags, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, rate_delivered):

		SOCK_OPS_GET_FIELD(rate_delivered, rate_delivered,

				   struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, rate_interval_us):

		SOCK_OPS_GET_FIELD(rate_interval_us, rate_interval_us,

				   struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, packets_out):

		SOCK_OPS_GET_FIELD(packets_out, packets_out, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, retrans_out):

		SOCK_OPS_GET_FIELD(retrans_out, retrans_out, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, total_retrans):

		SOCK_OPS_GET_FIELD(total_retrans, total_retrans,

				   struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, segs_in):

		SOCK_OPS_GET_FIELD(segs_in, segs_in, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, data_segs_in):

		SOCK_OPS_GET_FIELD(data_segs_in, data_segs_in, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, segs_out):

		SOCK_OPS_GET_FIELD(segs_out, segs_out, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, data_segs_out):

		SOCK_OPS_GET_FIELD(data_segs_out, data_segs_out,

				   struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, lost_out):

		SOCK_OPS_GET_FIELD(lost_out, lost_out, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, sacked_out):

		SOCK_OPS_GET_FIELD(sacked_out, sacked_out, struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, sk_txhash):

		SOCK_OPS_GET_FIELD(sk_txhash, sk_txhash, struct sock);

		break;



	case offsetof(struct bpf_sock_ops, bytes_received):

		SOCK_OPS_GET_FIELD(bytes_received, bytes_received,

				   struct tcp_sock);

		break;



	case offsetof(struct bpf_sock_ops, bytes_acked):

		SOCK_OPS_GET_FIELD(bytes_acked, bytes_acked, struct tcp_sock);

		break;

	}

	return insn - insn_buf;

}

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