OpenCloudOS-Kernel/samples/bpf/test_map_in_map.bpf.c

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/*
* 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 "vmlinux.h"
#include <linux/version.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
samples: bpf: Fix bpf programs with kprobe/sys_connect event Currently, BPF programs with kprobe/sys_connect does not work properly. Commit 34745aed515c ("samples/bpf: fix kprobe attachment issue on x64") This commit modifies the bpf_load behavior of kprobe events in the x64 architecture. If the current kprobe event target starts with "sys_*", add the prefix "__x64_" to the front of the event. Appending "__x64_" prefix with kprobe/sys_* event was appropriate as a solution to most of the problems caused by the commit below. commit d5a00528b58c ("syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()") However, there is a problem with the sys_connect kprobe event that does not work properly. For __sys_connect event, parameters can be fetched normally, but for __x64_sys_connect, parameters cannot be fetched. ffffffff818d3520 <__x64_sys_connect>: ffffffff818d3520: e8 fb df 32 00 callq 0xffffffff81c01520 <__fentry__> ffffffff818d3525: 48 8b 57 60 movq 96(%rdi), %rdx ffffffff818d3529: 48 8b 77 68 movq 104(%rdi), %rsi ffffffff818d352d: 48 8b 7f 70 movq 112(%rdi), %rdi ffffffff818d3531: e8 1a ff ff ff callq 0xffffffff818d3450 <__sys_connect> ffffffff818d3536: 48 98 cltq ffffffff818d3538: c3 retq ffffffff818d3539: 0f 1f 80 00 00 00 00 nopl (%rax) As the assembly code for __x64_sys_connect shows, parameters should be fetched and set into rdi, rsi, rdx registers prior to calling __sys_connect. Because of this problem, this commit fixes the sys_connect event by first getting the value of the rdi register and then the value of the rdi, rsi, and rdx register through an offset based on that value. Fixes: 34745aed515c ("samples/bpf: fix kprobe attachment issue on x64") Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200707184855.30968-2-danieltimlee@gmail.com
2020-07-08 02:48:52 +08:00
#include <bpf/bpf_core_read.h>
#define MAX_NR_PORTS 65536
#define EINVAL 22
#define ENOENT 2
/* map #0 */
struct inner_a {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, u32);
__type(value, int);
__uint(max_entries, MAX_NR_PORTS);
} port_a SEC(".maps");
/* map #1 */
struct inner_h {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, u32);
__type(value, int);
__uint(max_entries, 1);
} port_h SEC(".maps");
/* map #2 */
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, u32);
__type(value, int);
__uint(max_entries, 1);
} reg_result_h SEC(".maps");
/* map #3 */
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, u32);
__type(value, int);
__uint(max_entries, 1);
} inline_result_h SEC(".maps");
/* map #4 */ /* Test case #0 */
struct {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, MAX_NR_PORTS);
__uint(key_size, sizeof(u32));
__array(values, struct inner_a); /* use inner_a as inner map */
} a_of_port_a SEC(".maps");
/* map #5 */ /* Test case #1 */
struct {
__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
__uint(max_entries, 1);
__uint(key_size, sizeof(u32));
__array(values, struct inner_a); /* use inner_a as inner map */
} h_of_port_a SEC(".maps");
/* map #6 */ /* Test case #2 */
struct {
__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
__uint(max_entries, 1);
__uint(key_size, sizeof(u32));
__array(values, struct inner_h); /* use inner_h as inner map */
} h_of_port_h SEC(".maps");
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;
}
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;
}
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;
}
SEC("ksyscall/connect")
int BPF_KSYSCALL(trace_sys_connect, unsigned int fd, struct sockaddr_in6 *in6, int addrlen)
{
u16 test_case, port, dst6[8];
int ret, inline_ret, ret_key = 0;
u32 port_key;
void *outer_map, *inner_map;
bool inline_hash = false;
if (addrlen != sizeof(*in6))
return 0;
ret = bpf_probe_read_user(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_user(&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;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;