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: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c8cecf9..46520ea 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -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 */

diff --git a/net/core/filter.c b/net/core/filter.c
index 6936d19..a858ebc 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -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;
 }