100 lines
2.3 KiB
C
100 lines
2.3 KiB
C
/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include "vmlinux.h"
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#include <linux/version.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_core_read.h>
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, long);
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__type(value, long);
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__uint(max_entries, 1024);
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} my_map SEC(".maps");
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/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
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* example will no longer be meaningful
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*/
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SEC("kprobe/kfree_skb_reason")
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int bpf_prog2(struct pt_regs *ctx)
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{
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long loc = 0;
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long init_val = 1;
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long *value;
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/* read ip of kfree_skb_reason caller.
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* non-portable version of __builtin_return_address(0)
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*/
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BPF_KPROBE_READ_RET_IP(loc, ctx);
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value = bpf_map_lookup_elem(&my_map, &loc);
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if (value)
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*value += 1;
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else
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bpf_map_update_elem(&my_map, &loc, &init_val, BPF_ANY);
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return 0;
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}
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static unsigned int log2(unsigned int v)
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{
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unsigned int r;
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unsigned int shift;
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r = (v > 0xFFFF) << 4; v >>= r;
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shift = (v > 0xFF) << 3; v >>= shift; r |= shift;
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shift = (v > 0xF) << 2; v >>= shift; r |= shift;
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shift = (v > 0x3) << 1; v >>= shift; r |= shift;
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r |= (v >> 1);
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return r;
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}
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static unsigned int log2l(unsigned long v)
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{
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unsigned int hi = v >> 32;
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if (hi)
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return log2(hi) + 32;
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else
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return log2(v);
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}
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struct hist_key {
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char comm[16];
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u64 pid_tgid;
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u64 uid_gid;
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u64 index;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
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__uint(key_size, sizeof(struct hist_key));
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__uint(value_size, sizeof(long));
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__uint(max_entries, 1024);
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} my_hist_map SEC(".maps");
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SEC("ksyscall/write")
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int BPF_KSYSCALL(bpf_prog3, unsigned int fd, const char *buf, size_t count)
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{
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long init_val = 1;
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long *value;
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struct hist_key key;
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key.index = log2l(count);
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key.pid_tgid = bpf_get_current_pid_tgid();
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key.uid_gid = bpf_get_current_uid_gid();
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bpf_get_current_comm(&key.comm, sizeof(key.comm));
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value = bpf_map_lookup_elem(&my_hist_map, &key);
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if (value)
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__sync_fetch_and_add(value, 1);
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else
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bpf_map_update_elem(&my_hist_map, &key, &init_val, BPF_ANY);
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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u32 _version SEC("version") = LINUX_VERSION_CODE;
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