76 lines
1.7 KiB
C
76 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (c) 2021 Hengqi Chen */
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#include <vmlinux.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_core_read.h>
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#include <bpf/bpf_tracing.h>
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#include "gethostlatency.h"
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#define MAX_ENTRIES 10240
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const volatile pid_t target_pid = 0;
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, MAX_ENTRIES);
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__type(key, __u32);
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__type(value, struct event);
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} starts SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
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__uint(key_size, sizeof(__u32));
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__uint(value_size, sizeof(__u32));
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} events SEC(".maps");
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static int probe_entry(struct pt_regs *ctx)
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{
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if (!PT_REGS_PARM1(ctx))
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return 0;
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__u64 pid_tgid = bpf_get_current_pid_tgid();
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__u32 pid = pid_tgid >> 32;
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__u32 tid = (__u32)pid_tgid;
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struct event event = {};
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if (target_pid && target_pid != pid)
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return 0;
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event.time = bpf_ktime_get_ns();
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event.pid = pid;
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bpf_get_current_comm(&event.comm, sizeof(event.comm));
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bpf_probe_read_user(&event.host, sizeof(event.host), (void *)PT_REGS_PARM1(ctx));
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bpf_map_update_elem(&starts, &tid, &event, BPF_ANY);
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return 0;
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}
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static int probe_return(struct pt_regs *ctx)
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{
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__u32 tid = (__u32)bpf_get_current_pid_tgid();
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struct event *eventp;
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eventp = bpf_map_lookup_elem(&starts, &tid);
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if (!eventp)
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return 0;
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/* update time from timestamp to delta */
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eventp->time = bpf_ktime_get_ns() - eventp->time;
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bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU, eventp, sizeof(*eventp));
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bpf_map_delete_elem(&starts, &tid);
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return 0;
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}
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SEC("kprobe/handle_entry")
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int handle_entry(struct pt_regs *ctx)
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{
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return probe_entry(ctx);
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}
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SEC("kretprobe/handle_return")
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int handle_return(struct pt_regs *ctx)
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{
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return probe_return(ctx);
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}
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char LICENSE[] SEC("license") = "GPL";
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