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1d129d19 JP |
1 | /* |
2 | * tc_bpf.c BPF common code | |
3 | * | |
4 | * This program is free software; you can distribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | * | |
9 | * Authors: Daniel Borkmann <dborkman@redhat.com> | |
10 | * Jiri Pirko <jiri@resnulli.us> | |
11 | */ | |
12 | ||
13 | #include <stdio.h> | |
14 | #include <stdlib.h> | |
15 | #include <unistd.h> | |
16 | #include <string.h> | |
17 | #include <stdbool.h> | |
18 | #include <errno.h> | |
19 | #include <linux/filter.h> | |
20 | #include <linux/netlink.h> | |
21 | #include <linux/rtnetlink.h> | |
22 | ||
23 | #include "utils.h" | |
24 | #include "tc_util.h" | |
25 | #include "tc_bpf.h" | |
26 | ||
27 | int bpf_parse_string(char *arg, bool from_file, __u16 *bpf_len, | |
28 | char **bpf_string, bool *need_release, | |
29 | const char separator) | |
30 | { | |
31 | char sp; | |
32 | ||
33 | if (from_file) { | |
34 | size_t tmp_len, op_len = sizeof("65535 255 255 4294967295,"); | |
35 | char *tmp_string; | |
36 | FILE *fp; | |
37 | ||
38 | tmp_len = sizeof("4096,") + BPF_MAXINSNS * op_len; | |
39 | tmp_string = malloc(tmp_len); | |
40 | if (tmp_string == NULL) | |
41 | return -ENOMEM; | |
42 | ||
43 | memset(tmp_string, 0, tmp_len); | |
44 | ||
45 | fp = fopen(arg, "r"); | |
46 | if (fp == NULL) { | |
47 | perror("Cannot fopen"); | |
48 | free(tmp_string); | |
49 | return -ENOENT; | |
50 | } | |
51 | ||
52 | if (!fgets(tmp_string, tmp_len, fp)) { | |
53 | free(tmp_string); | |
54 | fclose(fp); | |
55 | return -EIO; | |
56 | } | |
57 | ||
58 | fclose(fp); | |
59 | ||
60 | *need_release = true; | |
61 | *bpf_string = tmp_string; | |
62 | } else { | |
63 | *need_release = false; | |
64 | *bpf_string = arg; | |
65 | } | |
66 | ||
67 | if (sscanf(*bpf_string, "%hu%c", bpf_len, &sp) != 2 || | |
68 | sp != separator) { | |
69 | if (*need_release) | |
70 | free(*bpf_string); | |
71 | return -EINVAL; | |
72 | } | |
73 | ||
74 | return 0; | |
75 | } | |
76 | ||
77 | int bpf_parse_ops(int argc, char **argv, struct sock_filter *bpf_ops, | |
78 | bool from_file) | |
79 | { | |
80 | char *bpf_string, *token, separator = ','; | |
81 | int ret = 0, i = 0; | |
82 | bool need_release; | |
83 | __u16 bpf_len = 0; | |
84 | ||
85 | if (argc < 1) | |
86 | return -EINVAL; | |
87 | if (bpf_parse_string(argv[0], from_file, &bpf_len, &bpf_string, | |
88 | &need_release, separator)) | |
89 | return -EINVAL; | |
90 | if (bpf_len == 0 || bpf_len > BPF_MAXINSNS) { | |
91 | ret = -EINVAL; | |
92 | goto out; | |
93 | } | |
94 | ||
95 | token = bpf_string; | |
96 | while ((token = strchr(token, separator)) && (++token)[0]) { | |
97 | if (i >= bpf_len) { | |
98 | fprintf(stderr, "Real program length exceeds encoded " | |
99 | "length parameter!\n"); | |
100 | ret = -EINVAL; | |
101 | goto out; | |
102 | } | |
103 | ||
104 | if (sscanf(token, "%hu %hhu %hhu %u,", | |
105 | &bpf_ops[i].code, &bpf_ops[i].jt, | |
106 | &bpf_ops[i].jf, &bpf_ops[i].k) != 4) { | |
107 | fprintf(stderr, "Error at instruction %d!\n", i); | |
108 | ret = -EINVAL; | |
109 | goto out; | |
110 | } | |
111 | ||
112 | i++; | |
113 | } | |
114 | ||
115 | if (i != bpf_len) { | |
116 | fprintf(stderr, "Parsed program length is less than encoded" | |
117 | "length parameter!\n"); | |
118 | ret = -EINVAL; | |
119 | goto out; | |
120 | } | |
121 | ret = bpf_len; | |
122 | ||
123 | out: | |
124 | if (need_release) | |
125 | free(bpf_string); | |
126 | ||
127 | return ret; | |
128 | } | |
129 | ||
130 | void bpf_print_ops(FILE *f, struct rtattr *bpf_ops, __u16 len) | |
131 | { | |
132 | struct sock_filter *ops = (struct sock_filter *) RTA_DATA(bpf_ops); | |
133 | int i; | |
134 | ||
135 | if (len == 0) | |
136 | return; | |
137 | ||
138 | fprintf(f, "bytecode \'%u,", len); | |
139 | ||
140 | for (i = 0; i < len - 1; i++) | |
141 | fprintf(f, "%hu %hhu %hhu %u,", ops[i].code, ops[i].jt, | |
142 | ops[i].jf, ops[i].k); | |
143 | ||
144 | fprintf(f, "%hu %hhu %hhu %u\'\n", ops[i].code, ops[i].jt, | |
145 | ops[i].jf, ops[i].k); | |
146 | } |