Martin KaFai Lau | fb30d4b | 2017-03-22 10:00:35 -0700 | [diff] [blame] | 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 | |
| 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 | |
| 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 | |
| 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") |
| 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; |