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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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02413cabd6
Remove the zero initialization in the sample programs where appropriate. Note that this is an optimization which is now possible, old programs still doing the zero initialization are just fine as well. Also, make sure we don't have padding issues when we don't memset() the entire struct anymore. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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 <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/version.h>
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#include <uapi/linux/bpf.h>
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#include "bpf_helpers.h"
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struct bpf_map_def SEC("maps") my_map = {
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.type = BPF_MAP_TYPE_HASH,
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.key_size = sizeof(long),
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.value_size = sizeof(long),
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.max_entries = 1024,
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};
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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")
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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 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 bpf_map_def SEC("maps") my_hist_map = {
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.type = BPF_MAP_TYPE_PERCPU_HASH,
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.key_size = sizeof(struct hist_key),
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.value_size = sizeof(long),
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.max_entries = 1024,
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};
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SEC("kprobe/sys_write")
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int bpf_prog3(struct pt_regs *ctx)
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{
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long write_size = PT_REGS_PARM3(ctx);
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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(write_size);
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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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