Holger Hans Peter Freyther | aaa3d08 | 2013-06-14 19:10:28 +0200 | [diff] [blame^] | 1 | /* Handling for loading a re-write file/database */ |
| 2 | /* |
| 3 | * (C) 2013 by On-Waves |
| 4 | * (C) 2013 by Holger Hans Peter Freyther <zecke@selfish.org> |
| 5 | * All Rights Reserved |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU Affero General Public License as published by |
| 9 | * the Free Software Foundation; either version 3 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU Affero General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Affero General Public License |
| 18 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 19 | * |
| 20 | */ |
| 21 | |
| 22 | #include <openbsc/nat_rewrite_trie.h> |
| 23 | #include <openbsc/debug.h> |
| 24 | |
| 25 | #include <osmocom/core/talloc.h> |
| 26 | #include <osmocom/core/utils.h> |
| 27 | |
| 28 | #include <assert.h> |
| 29 | #include <stdio.h> |
| 30 | #include <string.h> |
| 31 | #include <ctype.h> |
| 32 | |
| 33 | #define CHECK_IS_DIGIT_OR_FAIL(prefix, pos) \ |
| 34 | if (!isdigit(prefix[pos]) && prefix[pos] != '+') { \ |
| 35 | LOGP(DNAT, LOGL_ERROR, \ |
| 36 | "Prefix(%s) contains non ascii text at(%d=%c)\n", \ |
| 37 | prefix, pos, prefix[pos]); \ |
| 38 | goto fail; \ |
| 39 | } |
| 40 | #define TO_INT(c) \ |
| 41 | ((c) == '+' ? 10 : ((c - '0') % 10)) |
| 42 | |
| 43 | static void insert_rewrite_node(struct nat_rewrite_rule *rule, struct nat_rewrite *root) |
| 44 | { |
| 45 | struct nat_rewrite_rule *new = &root->rule; |
| 46 | |
| 47 | const size_t len = strlen(rule->prefix); |
| 48 | int i; |
| 49 | |
| 50 | if (len == 0) { |
| 51 | LOGP(DNAT, LOGL_ERROR, "An empty prefix does not make sense.\n"); |
| 52 | goto fail; |
| 53 | } |
| 54 | |
| 55 | for (i = 0; i < len - 1; ++i) { |
| 56 | int pos; |
| 57 | |
| 58 | /* check if the input is valid */ |
| 59 | CHECK_IS_DIGIT_OR_FAIL(rule->prefix, i); |
| 60 | |
| 61 | /* check if the next node is already valid */ |
| 62 | pos = TO_INT(rule->prefix[i]); |
| 63 | if (!new->rules[pos]) { |
| 64 | new->rules[pos] = talloc_zero(root, struct nat_rewrite_rule); |
| 65 | if (!new->rules[pos]) { |
| 66 | LOGP(DNAT, LOGL_ERROR, |
| 67 | "Failed to allocate memory.\n"); |
| 68 | goto fail; |
| 69 | } |
| 70 | |
| 71 | new->rules[pos]->empty = 1; |
| 72 | } |
| 73 | |
| 74 | /* we continue here */ |
| 75 | new = new->rules[pos]; |
| 76 | } |
| 77 | |
| 78 | /* new now points to the place where we want to add it */ |
| 79 | int pos; |
| 80 | |
| 81 | /* check if the input is valid */ |
| 82 | CHECK_IS_DIGIT_OR_FAIL(rule->prefix, (len - 1)); |
| 83 | |
| 84 | /* check if the next node is already valid */ |
| 85 | pos = TO_INT(rule->prefix[len - 1]); |
| 86 | if (!new->rules[pos]) |
| 87 | new->rules[pos] = rule; |
| 88 | else if (new->rules[pos]->empty) { |
| 89 | /* copy over entries */ |
| 90 | new->rules[pos]->empty = 0; |
| 91 | memcpy(new->rules[pos]->prefix, rule->prefix, sizeof(rule->prefix)); |
| 92 | memcpy(new->rules[pos]->rewrite, rule->rewrite, sizeof(rule->rewrite)); |
| 93 | talloc_free(rule); |
| 94 | } else { |
| 95 | LOGP(DNAT, LOGL_ERROR, |
| 96 | "Prefix(%s) is already installed\n", rule->prefix); |
| 97 | goto fail; |
| 98 | } |
| 99 | |
| 100 | root->prefixes += 1; |
| 101 | return; |
| 102 | |
| 103 | fail: |
| 104 | talloc_free(rule); |
| 105 | return; |
| 106 | } |
| 107 | |
| 108 | static void handle_line(struct nat_rewrite *rewrite, char *line) |
| 109 | { |
| 110 | char *split; |
| 111 | struct nat_rewrite_rule *rule; |
| 112 | size_t size_prefix, size_end, len; |
| 113 | |
| 114 | |
| 115 | /* Find the ',' in the line */ |
| 116 | len = strlen(line); |
| 117 | split = strstr(line, ","); |
| 118 | if (!split) { |
| 119 | LOGP(DNAT, LOGL_ERROR, "Line doesn't contain ','\n"); |
| 120 | return; |
| 121 | } |
| 122 | |
| 123 | /* Check if there is space for the rewrite rule */ |
| 124 | size_prefix = split - line; |
| 125 | if (len - size_prefix <= 2) { |
| 126 | LOGP(DNAT, LOGL_ERROR, "No rewrite available.\n"); |
| 127 | return; |
| 128 | } |
| 129 | |
| 130 | /* Continue after the ',' to the end */ |
| 131 | split = &line[size_prefix + 1]; |
| 132 | size_end = strlen(split) - 1; |
| 133 | |
| 134 | /* Check if both strings can fit into the static array */ |
| 135 | if (size_prefix > sizeof(rule->prefix) - 1) { |
| 136 | LOGP(DNAT, LOGL_ERROR, |
| 137 | "Prefix is too long with %zu\n", size_prefix); |
| 138 | return; |
| 139 | } |
| 140 | |
| 141 | if (size_end > sizeof(rule->rewrite) - 1) { |
| 142 | LOGP(DNAT, LOGL_ERROR, |
| 143 | "Rewrite is too long with %zu on %s\n", |
| 144 | size_end, &line[size_prefix + 1]); |
| 145 | return; |
| 146 | } |
| 147 | |
| 148 | /* Now create the entry and insert it into the trie */ |
| 149 | rule = talloc_zero(rewrite, struct nat_rewrite_rule); |
| 150 | if (!rule) { |
| 151 | LOGP(DNAT, LOGL_ERROR, "Can not allocate memory\n"); |
| 152 | return; |
| 153 | } |
| 154 | |
| 155 | memcpy(rule->prefix, line, size_prefix); |
| 156 | assert(size_prefix < sizeof(rule->prefix)); |
| 157 | rule->prefix[size_prefix] = '\0'; |
| 158 | |
| 159 | memcpy(rule->rewrite, split, size_end); |
| 160 | assert(size_end < sizeof(rule->rewrite)); |
| 161 | rule->rewrite[size_end] = '\0'; |
| 162 | |
| 163 | /* now insert and balance the tree */ |
| 164 | insert_rewrite_node(rule, rewrite); |
| 165 | } |
| 166 | |
| 167 | struct nat_rewrite *nat_rewrite_parse(void *ctx, const char *filename) |
| 168 | { |
| 169 | FILE *file; |
| 170 | char *line = NULL; |
| 171 | size_t n = 2342; |
| 172 | struct nat_rewrite *res; |
| 173 | |
| 174 | file = fopen(filename, "r"); |
| 175 | if (!file) |
| 176 | return NULL; |
| 177 | |
| 178 | res = talloc_zero(ctx, struct nat_rewrite); |
| 179 | if (!res) { |
| 180 | fclose(file); |
| 181 | return NULL; |
| 182 | } |
| 183 | |
| 184 | /* mark the root as empty */ |
| 185 | res->rule.empty = 1; |
| 186 | |
| 187 | while (getline(&line, &n, file) != -1) { |
| 188 | handle_line(res, line); |
| 189 | } |
| 190 | |
| 191 | free(line); |
| 192 | fclose(file); |
| 193 | return res; |
| 194 | } |
| 195 | |
| 196 | /** |
| 197 | * Simple find that tries to do a longest match... |
| 198 | */ |
| 199 | struct nat_rewrite_rule *nat_rewrite_lookup(struct nat_rewrite *rewrite, |
| 200 | const char *prefix) |
| 201 | { |
| 202 | struct nat_rewrite_rule *rule = &rewrite->rule; |
| 203 | struct nat_rewrite_rule *last = NULL; |
| 204 | const int len = OSMO_MIN(strlen(prefix), (sizeof(rule->prefix) - 1)); |
| 205 | int i; |
| 206 | |
| 207 | for (i = 0; rule && i < len; ++i) { |
| 208 | int pos; |
| 209 | |
| 210 | CHECK_IS_DIGIT_OR_FAIL(prefix, i); |
| 211 | pos = TO_INT(prefix[i]); |
| 212 | |
| 213 | rule = rule->rules[pos]; |
| 214 | if (rule && !rule->empty) |
| 215 | last = rule; |
| 216 | } |
| 217 | |
| 218 | return last; |
| 219 | |
| 220 | fail: |
| 221 | return NULL; |
| 222 | } |
| 223 | |
| 224 | static void nat_rewrite_dump_rec(struct nat_rewrite_rule *rule) |
| 225 | { |
| 226 | int i; |
| 227 | if (!rule->empty) |
| 228 | printf("%s,%s\n", rule->prefix, rule->rewrite); |
| 229 | |
| 230 | for (i = 0; i < ARRAY_SIZE(rule->rules); ++i) { |
| 231 | if (!rule->rules[i]) |
| 232 | continue; |
| 233 | nat_rewrite_dump_rec(rule->rules[i]); |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | void nat_rewrite_dump(struct nat_rewrite *rewrite) |
| 238 | { |
| 239 | nat_rewrite_dump_rec(&rewrite->rule); |
| 240 | } |