linux/samples/bpf/tcp_dumpstats_kern.c

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// SPDX-License-Identifier: GPL-2.0
/* Refer to samples/bpf/tcp_bpf.readme for the instructions on
* how to run this sample program.
*/
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
#define INTERVAL 1000000000ULL
int _version SEC("version") = 1;
char _license[] SEC("license") = "GPL";
struct {
__u32 type;
__u32 map_flags;
int *key;
__u64 *value;
} bpf_next_dump SEC(".maps") = {
.type = BPF_MAP_TYPE_SK_STORAGE,
.map_flags = BPF_F_NO_PREALLOC,
};
SEC("sockops")
int _sockops(struct bpf_sock_ops *ctx)
{
struct bpf_tcp_sock *tcp_sk;
struct bpf_sock *sk;
__u64 *next_dump;
__u64 now;
switch (ctx->op) {
case BPF_SOCK_OPS_TCP_CONNECT_CB:
bpf_sock_ops_cb_flags_set(ctx, BPF_SOCK_OPS_RTT_CB_FLAG);
return 1;
case BPF_SOCK_OPS_RTT_CB:
break;
default:
return 1;
}
sk = ctx->sk;
if (!sk)
return 1;
next_dump = bpf_sk_storage_get(&bpf_next_dump, sk, 0,
BPF_SK_STORAGE_GET_F_CREATE);
if (!next_dump)
return 1;
now = bpf_ktime_get_ns();
if (now < *next_dump)
return 1;
tcp_sk = bpf_tcp_sock(sk);
if (!tcp_sk)
return 1;
*next_dump = now + INTERVAL;
bpf_printk("dsack_dups=%u delivered=%u\n",
tcp_sk->dsack_dups, tcp_sk->delivered);
bpf_printk("delivered_ce=%u icsk_retransmits=%u\n",
tcp_sk->delivered_ce, tcp_sk->icsk_retransmits);
return 1;
}