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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172// SPDX-License-Identifier: GPL-2.0// Copyright (c) 2019 Facebook
#include <stdint.h>#include <string.h>
#include <linux/stddef.h>#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_compiler.h"#include "bpf_misc.h"
/* tcp_mem sysctl has only 3 ints, but this test is doing TCP_MEM_LOOPS */#define TCP_MEM_LOOPS 20 /* because 30 doesn't fit into 512 bytes of stack */#define MAX_ULONG_STR_LEN 7#define MAX_VALUE_STR_LEN (TCP_MEM_LOOPS * MAX_ULONG_STR_LEN)
const char tcp_mem_name[] = "net/ipv4/tcp_mem/very_very_very_very_long_pointless_string_to_stress_byte_loop";static __attribute__((noinline)) int is_tcp_mem(struct bpf_sysctl *ctx){ unsigned char i; char name[sizeof(tcp_mem_name)]; int ret;
memset(name, 0, sizeof(name)); ret = bpf_sysctl_get_name(ctx, name, sizeof(name), 0); if (ret < 0 || ret != sizeof(tcp_mem_name) - 1) return 0;
__pragma_loop_no_unroll for (i = 0; i < sizeof(tcp_mem_name); ++i) if (name[i] != tcp_mem_name[i]) return 0;
return 1;}
SEC("cgroup/sysctl")int sysctl_tcp_mem(struct bpf_sysctl *ctx){ unsigned long tcp_mem[TCP_MEM_LOOPS] = {}; char value[MAX_VALUE_STR_LEN]; unsigned char i, off = 0; int ret;
if (ctx->write) return 0;
if (!is_tcp_mem(ctx)) return 0;
ret = bpf_sysctl_get_current_value(ctx, value, MAX_VALUE_STR_LEN); if (ret < 0 || ret >= MAX_VALUE_STR_LEN) return 0;
__pragma_loop_no_unroll for (i = 0; i < ARRAY_SIZE(tcp_mem); ++i) { ret = bpf_strtoul(value + off, MAX_ULONG_STR_LEN, 0, tcp_mem + i); if (ret <= 0 || ret > MAX_ULONG_STR_LEN) return 0; off += ret & MAX_ULONG_STR_LEN; }
return tcp_mem[0] < tcp_mem[1] && tcp_mem[1] < tcp_mem[2];}
char _license[] SEC("license") = "GPL";