1 /*
2 * Copyright (c) 2017 Facebook
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
7 */
8 #define KBUILD_MODNAME "foo"
9 #include <linux/ptrace.h>
10 #include <linux/version.h>
11 #include <uapi/linux/bpf.h>
12 #include <uapi/linux/in6.h>
13 #include "bpf_helpers.h"
14
15 #define MAX_NR_PORTS 65536
16
17 /* map #0 */
18 struct bpf_map_def SEC("maps") port_a = {
19 .type = BPF_MAP_TYPE_ARRAY,
20 .key_size = sizeof(u32),
21 .value_size = sizeof(int),
22 .max_entries = MAX_NR_PORTS,
23 };
24
25 /* map #1 */
26 struct bpf_map_def SEC("maps") port_h = {
27 .type = BPF_MAP_TYPE_HASH,
28 .key_size = sizeof(u32),
29 .value_size = sizeof(int),
30 .max_entries = 1,
31 };
32
33 /* map #2 */
34 struct bpf_map_def SEC("maps") reg_result_h = {
35 .type = BPF_MAP_TYPE_HASH,
36 .key_size = sizeof(u32),
37 .value_size = sizeof(int),
38 .max_entries = 1,
39 };
40
41 /* map #3 */
42 struct bpf_map_def SEC("maps") inline_result_h = {
43 .type = BPF_MAP_TYPE_HASH,
44 .key_size = sizeof(u32),
45 .value_size = sizeof(int),
46 .max_entries = 1,
47 };
48
49 /* map #4 */ /* Test case #0 */
50 struct bpf_map_def SEC("maps") a_of_port_a = {
51 .type = BPF_MAP_TYPE_ARRAY_OF_MAPS,
52 .key_size = sizeof(u32),
53 .inner_map_idx = 0, /* map_fd[0] is port_a */
54 .max_entries = MAX_NR_PORTS,
55 };
56
57 /* map #5 */ /* Test case #1 */
58 struct bpf_map_def SEC("maps") h_of_port_a = {
59 .type = BPF_MAP_TYPE_HASH_OF_MAPS,
60 .key_size = sizeof(u32),
61 .inner_map_idx = 0, /* map_fd[0] is port_a */
62 .max_entries = 1,
63 };
64
65 /* map #6 */ /* Test case #2 */
66 struct bpf_map_def SEC("maps") h_of_port_h = {
67 .type = BPF_MAP_TYPE_HASH_OF_MAPS,
68 .key_size = sizeof(u32),
69 .inner_map_idx = 1, /* map_fd[1] is port_h */
70 .max_entries = 1,
71 };
72
do_reg_lookup(void * inner_map,u32 port)73 static __always_inline int do_reg_lookup(void *inner_map, u32 port)
74 {
75 int *result;
76
77 result = bpf_map_lookup_elem(inner_map, &port);
78 return result ? *result : -ENOENT;
79 }
80
do_inline_array_lookup(void * inner_map,u32 port)81 static __always_inline int do_inline_array_lookup(void *inner_map, u32 port)
82 {
83 int *result;
84
85 if (inner_map != &port_a)
86 return -EINVAL;
87
88 result = bpf_map_lookup_elem(&port_a, &port);
89 return result ? *result : -ENOENT;
90 }
91
do_inline_hash_lookup(void * inner_map,u32 port)92 static __always_inline int do_inline_hash_lookup(void *inner_map, u32 port)
93 {
94 int *result;
95
96 if (inner_map != &port_h)
97 return -EINVAL;
98
99 result = bpf_map_lookup_elem(&port_h, &port);
100 return result ? *result : -ENOENT;
101 }
102
103 SEC("kprobe/sys_connect")
trace_sys_connect(struct pt_regs * ctx)104 int trace_sys_connect(struct pt_regs *ctx)
105 {
106 struct sockaddr_in6 *in6;
107 u16 test_case, port, dst6[8];
108 int addrlen, ret, inline_ret, ret_key = 0;
109 u32 port_key;
110 void *outer_map, *inner_map;
111 bool inline_hash = false;
112
113 in6 = (struct sockaddr_in6 *)PT_REGS_PARM2(ctx);
114 addrlen = (int)PT_REGS_PARM3(ctx);
115
116 if (addrlen != sizeof(*in6))
117 return 0;
118
119 ret = bpf_probe_read(dst6, sizeof(dst6), &in6->sin6_addr);
120 if (ret) {
121 inline_ret = ret;
122 goto done;
123 }
124
125 if (dst6[0] != 0xdead || dst6[1] != 0xbeef)
126 return 0;
127
128 test_case = dst6[7];
129
130 ret = bpf_probe_read(&port, sizeof(port), &in6->sin6_port);
131 if (ret) {
132 inline_ret = ret;
133 goto done;
134 }
135
136 port_key = port;
137
138 ret = -ENOENT;
139 if (test_case == 0) {
140 outer_map = &a_of_port_a;
141 } else if (test_case == 1) {
142 outer_map = &h_of_port_a;
143 } else if (test_case == 2) {
144 outer_map = &h_of_port_h;
145 } else {
146 ret = __LINE__;
147 inline_ret = ret;
148 goto done;
149 }
150
151 inner_map = bpf_map_lookup_elem(outer_map, &port_key);
152 if (!inner_map) {
153 ret = __LINE__;
154 inline_ret = ret;
155 goto done;
156 }
157
158 ret = do_reg_lookup(inner_map, port_key);
159
160 if (test_case == 0 || test_case == 1)
161 inline_ret = do_inline_array_lookup(inner_map, port_key);
162 else
163 inline_ret = do_inline_hash_lookup(inner_map, port_key);
164
165 done:
166 bpf_map_update_elem(®_result_h, &ret_key, &ret, BPF_ANY);
167 bpf_map_update_elem(&inline_result_h, &ret_key, &inline_ret, BPF_ANY);
168
169 return 0;
170 }
171
172 char _license[] SEC("license") = "GPL";
173 u32 _version SEC("version") = LINUX_VERSION_CODE;
174