cregit-Linux how code gets into the kernel

Release 4.14 samples/bpf/test_map_in_map_kern.c

Directory: samples/bpf
/*
 * Copyright (c) 2017 Facebook
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */

#define KBUILD_MODNAME "foo"
#include <linux/ptrace.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include <uapi/linux/in6.h>
#include "bpf_helpers.h"


#define MAX_NR_PORTS 65536

/* map #0 */
struct bpf_map_def SEC("maps") port_a = {
	.type = BPF_MAP_TYPE_ARRAY,
	.key_size = sizeof(u32),
	.value_size = sizeof(int),
	.max_entries = MAX_NR_PORTS,
};

/* map #1 */
struct bpf_map_def SEC("maps") port_h = {
	.type = BPF_MAP_TYPE_HASH,
	.key_size = sizeof(u32),
	.value_size = sizeof(int),
	.max_entries = 1,
};

/* map #2 */
struct bpf_map_def SEC("maps") reg_result_h = {
	.type = BPF_MAP_TYPE_HASH,
	.key_size = sizeof(u32),
	.value_size = sizeof(int),
	.max_entries = 1,
};

/* map #3 */
struct bpf_map_def SEC("maps") inline_result_h = {
	.type = BPF_MAP_TYPE_HASH,
	.key_size = sizeof(u32),
	.value_size = sizeof(int),
	.max_entries = 1,
};

/* map #4 */ /* Test case #0 */
struct bpf_map_def SEC("maps") a_of_port_a = {
	.type = BPF_MAP_TYPE_ARRAY_OF_MAPS,
	.key_size = sizeof(u32),
	.inner_map_idx = 0, /* map_fd[0] is port_a */
	.max_entries = MAX_NR_PORTS,
};

/* map #5 */ /* Test case #1 */
struct bpf_map_def SEC("maps") h_of_port_a = {
	.type = BPF_MAP_TYPE_HASH_OF_MAPS,
	.key_size = sizeof(u32),
	.inner_map_idx = 0, /* map_fd[0] is port_a */
	.max_entries = 1,
};

/* map #6 */ /* Test case #2 */
struct bpf_map_def SEC("maps") h_of_port_h = {
	.type = BPF_MAP_TYPE_HASH_OF_MAPS,
	.key_size = sizeof(u32),
	.inner_map_idx = 1, /* map_fd[1] is port_h */
	.max_entries = 1,
};


static __always_inline int do_reg_lookup(void *inner_map, u32 port) { int *result; result = bpf_map_lookup_elem(inner_map, &port); return result ? *result : -ENOENT; }

Contributors

PersonTokensPropCommitsCommitProp
Martin KaFai Lau37100.00%1100.00%
Total37100.00%1100.00%


static __always_inline int do_inline_array_lookup(void *inner_map, u32 port) { int *result; if (inner_map != &port_a) return -EINVAL; result = bpf_map_lookup_elem(&port_a, &port); return result ? *result : -ENOENT; }

Contributors

PersonTokensPropCommitsCommitProp
Martin KaFai Lau49100.00%1100.00%
Total49100.00%1100.00%


static __always_inline int do_inline_hash_lookup(void *inner_map, u32 port) { int *result; if (inner_map != &port_h) return -EINVAL; result = bpf_map_lookup_elem(&port_h, &port); return result ? *result : -ENOENT; }

Contributors

PersonTokensPropCommitsCommitProp
Martin KaFai Lau49100.00%1100.00%
Total49100.00%1100.00%

SEC("kprobe/sys_connect")
int trace_sys_connect(struct pt_regs *ctx) { struct sockaddr_in6 *in6; u16 test_case, port, dst6[8]; int addrlen, ret, inline_ret, ret_key = 0; u32 port_key; void *outer_map, *inner_map; bool inline_hash = false; in6 = (struct sockaddr_in6 *)PT_REGS_PARM2(ctx); addrlen = (int)PT_REGS_PARM3(ctx); if (addrlen != sizeof(*in6)) return 0; ret = bpf_probe_read(dst6, sizeof(dst6), &in6->sin6_addr); if (ret) { inline_ret = ret; goto done; } if (dst6[0] != 0xdead || dst6[1] != 0xbeef) return 0; test_case = dst6[7]; ret = bpf_probe_read(&port, sizeof(port), &in6->sin6_port); if (ret) { inline_ret = ret; goto done; } port_key = port; ret = -ENOENT; if (test_case == 0) { outer_map = &a_of_port_a; } else if (test_case == 1) { outer_map = &h_of_port_a; } else if (test_case == 2) { outer_map = &h_of_port_h; } else { ret = __LINE__; inline_ret = ret; goto done; } inner_map = bpf_map_lookup_elem(outer_map, &port_key); if (!inner_map) { ret = __LINE__; inline_ret = ret; goto done; } ret = do_reg_lookup(inner_map, port_key); if (test_case == 0 || test_case == 1) inline_ret = do_inline_array_lookup(inner_map, port_key); else inline_ret = do_inline_hash_lookup(inner_map, port_key); done: bpf_map_update_elem(&reg_result_h, &ret_key, &ret, BPF_ANY); bpf_map_update_elem(&inline_result_h, &ret_key, &inline_ret, BPF_ANY); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Martin KaFai Lau336100.00%1100.00%
Total336100.00%1100.00%

char _license[] SEC("license") = "GPL"; u32 _version SEC("version") = LINUX_VERSION_CODE;

Overall Contributors

PersonTokensPropCommitsCommitProp
Martin KaFai Lau774100.00%1100.00%
Total774100.00%1100.00%
Directory: samples/bpf
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.