samples/bpf/tcp_dumpstats_kern.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Refer to samples/bpf/tcp_bpf.readme for the instructions on
0003  * how to run this sample program.
0004  */
0005 #include <linux/bpf.h>
0006
0007 #include <bpf/bpf_helpers.h>
0008 #include <bpf/bpf_endian.h>
0009
0010 #define INTERVAL            1000000000ULL
0011
0012 int _version SEC("version") = 1;
0013 char _license[] SEC("license") = "GPL";
0014
0015 struct {
0016     __u32 type;
0017     __u32 map_flags;
0018     int *key;
0019     __u64 *value;
0020 } bpf_next_dump SEC(".maps") = {
0021     .type = BPF_MAP_TYPE_SK_STORAGE,
0022     .map_flags = BPF_F_NO_PREALLOC,
0023 };
0024
0025 SEC("sockops")
0026 int _sockops(struct bpf_sock_ops *ctx)
0027 {
0028     struct bpf_tcp_sock *tcp_sk;
0029     struct bpf_sock *sk;
0030     __u64 *next_dump;
0031     __u64 now;
0032
0033     switch (ctx->op) {
0034     case BPF_SOCK_OPS_TCP_CONNECT_CB:
0035         bpf_sock_ops_cb_flags_set(ctx, BPF_SOCK_OPS_RTT_CB_FLAG);
0036         return 1;
0037     case BPF_SOCK_OPS_RTT_CB:
0038         break;
0039     default:
0040         return 1;
0041     }
0042
0043     sk = ctx->sk;
0044     if (!sk)
0045         return 1;
0046
0047     next_dump = bpf_sk_storage_get(&bpf_next_dump, sk, 0,
0048                        BPF_SK_STORAGE_GET_F_CREATE);
0049     if (!next_dump)
0050         return 1;
0051
0052     now = bpf_ktime_get_ns();
0053     if (now < *next_dump)
0054         return 1;
0055
0056     tcp_sk = bpf_tcp_sock(sk);
0057     if (!tcp_sk)
0058         return 1;
0059
0060     *next_dump = now + INTERVAL;
0061
0062     bpf_printk("dsack_dups=%u delivered=%u\n",
0063            tcp_sk->dsack_dups, tcp_sk->delivered);
0064     bpf_printk("delivered_ce=%u icsk_retransmits=%u\n",
0065            tcp_sk->delivered_ce, tcp_sk->icsk_retransmits);
0066
0067     return 1;
0068 }