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bpf: Add support for reading sk_state and more
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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: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Lawrence Brakmo authored and Alexei Starovoitov committed Jan 26, 2018
1 parent f89013f commit 44f0e43
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Showing 2 changed files with 154 additions and 11 deletions.
22 changes: 22 additions & 0 deletions include/uapi/linux/bpf.h
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Expand Up @@ -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 */
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143 changes: 132 additions & 11 deletions net/core/filter.c
View file
Expand Up @@ -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,
Expand Down Expand Up @@ -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 { \
Expand Down Expand Up @@ -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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