* It is a trie. The max depth of the trie is the length of the longest prefix. The lookup is O(lookuped_prefix), but as the prefix length is limited, the lookup time is constant. * Each node can hold the entire prefix, has place for the rewrite rule with up to three digits. * A trie with 20k entries will take about 3MB ram. * Filling the trie 100 times takes ~800ms on my i7 laptop * 10.000.000 lookups take 315ms.. (for the same prefix). * 93/99 lines are tested, 6/6 functions are tested, 49 of 54 branches are tested. Only memory allocation failures are not covered * A late addition is to handle the '+' sign and to increase the number of chars in the rewrite prefix. The timing/line coverage has not been updated after this change.changes/88/3188/1
Holger Hans Peter Freyther
10 years ago
committed by
Holger Hans Peter Freyther
parent
b718ad397e
commit
85d3b34ed2
@ -0,0 +1,44 @@ |
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/*
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* (C) 2013 by On-Waves |
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* (C) 2013 by Holger Hans Peter Freyther <zecke@selfish.org> |
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* All Rights Reserved |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU Affero General Public License as published by |
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* the Free Software Foundation; either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Affero General Public License for more details. |
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* |
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* You should have received a copy of the GNU Affero General Public License |
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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* |
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*/ |
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#ifndef NAT_REWRITE_FILE_H |
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#define NAT_REWRITE_FILE_H |
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#include <osmocom/core/linuxrbtree.h> |
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struct nat_rewrite_rule { |
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/* For digits 0-9 and + */ |
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struct nat_rewrite_rule *rules[11]; |
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char empty; |
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char prefix[14]; |
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char rewrite[4]; |
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}; |
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struct nat_rewrite { |
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struct nat_rewrite_rule rule; |
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size_t prefixes; |
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}; |
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struct nat_rewrite *nat_rewrite_parse(void *ctx, const char *filename); |
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struct nat_rewrite_rule *nat_rewrite_lookup(struct nat_rewrite *, const char *prefix); |
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void nat_rewrite_dump(struct nat_rewrite *rewr); |
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#endif |
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@ -0,0 +1,240 @@ |
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/* Handling for loading a re-write file/database */ |
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/*
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* (C) 2013 by On-Waves |
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* (C) 2013 by Holger Hans Peter Freyther <zecke@selfish.org> |
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* All Rights Reserved |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU Affero General Public License as published by |
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* the Free Software Foundation; either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Affero General Public License for more details. |
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* |
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* You should have received a copy of the GNU Affero General Public License |
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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* |
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*/ |
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#include <openbsc/nat_rewrite_trie.h> |
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#include <openbsc/debug.h> |
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#include <osmocom/core/talloc.h> |
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#include <osmocom/core/utils.h> |
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#include <assert.h> |
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#include <stdio.h> |
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#include <string.h> |
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#include <ctype.h> |
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#define CHECK_IS_DIGIT_OR_FAIL(prefix, pos) \ |
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if (!isdigit(prefix[pos]) && prefix[pos] != '+') { \
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LOGP(DNAT, LOGL_ERROR, \
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"Prefix(%s) contains non ascii text at(%d=%c)\n", \
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prefix, pos, prefix[pos]); \
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goto fail; \
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} |
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#define TO_INT(c) \ |
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((c) == '+' ? 10 : ((c - '0') % 10)) |
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static void insert_rewrite_node(struct nat_rewrite_rule *rule, struct nat_rewrite *root) |
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{ |
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struct nat_rewrite_rule *new = &root->rule; |
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const size_t len = strlen(rule->prefix); |
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int i; |
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if (len == 0) { |
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LOGP(DNAT, LOGL_ERROR, "An empty prefix does not make sense.\n"); |
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goto fail; |
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} |
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for (i = 0; i < len - 1; ++i) { |
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int pos; |
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/* check if the input is valid */ |
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CHECK_IS_DIGIT_OR_FAIL(rule->prefix, i); |
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/* check if the next node is already valid */ |
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pos = TO_INT(rule->prefix[i]); |
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if (!new->rules[pos]) { |
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new->rules[pos] = talloc_zero(root, struct nat_rewrite_rule); |
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if (!new->rules[pos]) { |
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LOGP(DNAT, LOGL_ERROR, |
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"Failed to allocate memory.\n"); |
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goto fail; |
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} |
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new->rules[pos]->empty = 1; |
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} |
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/* we continue here */ |
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new = new->rules[pos]; |
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} |
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/* new now points to the place where we want to add it */ |
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int pos; |
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/* check if the input is valid */ |
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CHECK_IS_DIGIT_OR_FAIL(rule->prefix, (len - 1)); |
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/* check if the next node is already valid */ |
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pos = TO_INT(rule->prefix[len - 1]); |
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if (!new->rules[pos]) |
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new->rules[pos] = rule; |
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else if (new->rules[pos]->empty) { |
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/* copy over entries */ |
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new->rules[pos]->empty = 0; |
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memcpy(new->rules[pos]->prefix, rule->prefix, sizeof(rule->prefix)); |
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memcpy(new->rules[pos]->rewrite, rule->rewrite, sizeof(rule->rewrite)); |
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talloc_free(rule); |
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} else { |
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LOGP(DNAT, LOGL_ERROR, |
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"Prefix(%s) is already installed\n", rule->prefix); |
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goto fail; |
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} |
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root->prefixes += 1; |
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return; |
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fail: |
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talloc_free(rule); |
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return; |
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} |
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static void handle_line(struct nat_rewrite *rewrite, char *line) |
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{ |
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char *split; |
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struct nat_rewrite_rule *rule; |
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size_t size_prefix, size_end, len; |
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/* Find the ',' in the line */ |
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len = strlen(line); |
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split = strstr(line, ","); |
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if (!split) { |
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LOGP(DNAT, LOGL_ERROR, "Line doesn't contain ','\n"); |
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return; |
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} |
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/* Check if there is space for the rewrite rule */ |
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size_prefix = split - line; |
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if (len - size_prefix <= 2) { |
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LOGP(DNAT, LOGL_ERROR, "No rewrite available.\n"); |
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return; |
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} |
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/* Continue after the ',' to the end */ |
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split = &line[size_prefix + 1]; |
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size_end = strlen(split) - 1; |
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/* Check if both strings can fit into the static array */ |
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if (size_prefix > sizeof(rule->prefix) - 1) { |
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LOGP(DNAT, LOGL_ERROR, |
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"Prefix is too long with %zu\n", size_prefix); |
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return; |
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} |
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if (size_end > sizeof(rule->rewrite) - 1) { |
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LOGP(DNAT, LOGL_ERROR, |
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"Rewrite is too long with %zu on %s\n", |
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size_end, &line[size_prefix + 1]); |
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return; |
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} |
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/* Now create the entry and insert it into the trie */ |
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rule = talloc_zero(rewrite, struct nat_rewrite_rule); |
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if (!rule) { |
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LOGP(DNAT, LOGL_ERROR, "Can not allocate memory\n"); |
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return; |
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} |
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memcpy(rule->prefix, line, size_prefix); |
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assert(size_prefix < sizeof(rule->prefix)); |
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rule->prefix[size_prefix] = '\0'; |
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memcpy(rule->rewrite, split, size_end); |
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assert(size_end < sizeof(rule->rewrite)); |
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rule->rewrite[size_end] = '\0'; |
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/* now insert and balance the tree */ |
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insert_rewrite_node(rule, rewrite); |
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} |
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struct nat_rewrite *nat_rewrite_parse(void *ctx, const char *filename) |
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{ |
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FILE *file; |
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char *line = NULL; |
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size_t n = 2342; |
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struct nat_rewrite *res; |
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file = fopen(filename, "r"); |
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if (!file) |
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return NULL; |
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res = talloc_zero(ctx, struct nat_rewrite); |
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if (!res) { |
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fclose(file); |
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return NULL; |
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} |
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/* mark the root as empty */ |
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res->rule.empty = 1; |
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while (getline(&line, &n, file) != -1) { |
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handle_line(res, line); |
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} |
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free(line); |
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fclose(file); |
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return res; |
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} |
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/**
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* Simple find that tries to do a longest match... |
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*/ |
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struct nat_rewrite_rule *nat_rewrite_lookup(struct nat_rewrite *rewrite, |
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const char *prefix) |
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{ |
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struct nat_rewrite_rule *rule = &rewrite->rule; |
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struct nat_rewrite_rule *last = NULL; |
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const int len = OSMO_MIN(strlen(prefix), (sizeof(rule->prefix) - 1)); |
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int i; |
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for (i = 0; rule && i < len; ++i) { |
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int pos; |
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CHECK_IS_DIGIT_OR_FAIL(prefix, i); |
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pos = TO_INT(prefix[i]); |
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rule = rule->rules[pos]; |
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if (rule && !rule->empty) |
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last = rule; |
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} |
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return last; |
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fail: |
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return NULL; |
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} |
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static void nat_rewrite_dump_rec(struct nat_rewrite_rule *rule) |
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{ |
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int i; |
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if (!rule->empty) |
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printf("%s,%s\n", rule->prefix, rule->rewrite); |
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for (i = 0; i < ARRAY_SIZE(rule->rules); ++i) { |
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if (!rule->rules[i]) |
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continue; |
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nat_rewrite_dump_rec(rule->rules[i]); |
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} |
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} |
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void nat_rewrite_dump(struct nat_rewrite *rewrite) |
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{ |
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nat_rewrite_dump_rec(&rewrite->rule); |
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} |
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@ -0,0 +1,18 @@ |
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AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include
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AM_CFLAGS=-Wall -ggdb3 $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOSCCP_CFLAGS) $(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS)
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AM_LDFLAGS = $(COVERAGE_LDFLAGS)
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EXTRA_DIST = bsc_nat_trie_test.ok prefixes.csv
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noinst_PROGRAMS = bsc_nat_trie_test
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bsc_nat_trie_test_SOURCES = bsc_nat_trie_test.c \
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$(top_srcdir)/src/osmo-bsc_nat/bsc_nat_rewrite_trie.c
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bsc_nat_trie_test_LDADD = $(top_builddir)/src/libbsc/libbsc.a \
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$(top_srcdir)/src/libctrl/libctrl.a \
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$(top_srcdir)/src/libmgcp/libmgcp.a \
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$(top_srcdir)/src/libtrau/libtrau.a \
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$(top_srcdir)/src/libcommon/libcommon.a \
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$(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) -lrt \
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$(LIBOSMOSCCP_LIBS) $(LIBOSMOVTY_LIBS) \
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$(LIBOSMOABIS_LIBS)
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@ -0,0 +1,87 @@ |
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/*
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* (C) 2013 by On-Waves |
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* (C) 2013 by Holger Hans Peter Freyther <zecke@selfish.org> |
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* All Rights Reserved |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU Affero General Public License as published by |
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* the Free Software Foundation; either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Affero General Public License for more details. |
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* |
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* You should have received a copy of the GNU Affero General Public License |
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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* |
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*/ |
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#include <openbsc/nat_rewrite_trie.h> |
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#include <openbsc/debug.h> |
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#include <osmocom/core/application.h> |
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#include <osmocom/core/backtrace.h> |
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#include <osmocom/core/talloc.h> |
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#include <osmocom/core/utils.h> |
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#include <string.h> |
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int main(int argc, char **argv) |
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{ |
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struct nat_rewrite *trie; |
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osmo_init_logging(&log_info); |
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printf("Testing the trie\n"); |
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trie = nat_rewrite_parse(NULL, "prefixes.csv"); |
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OSMO_ASSERT(trie); |
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/* verify that it has been parsed */ |
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OSMO_ASSERT(trie->prefixes == 17); |
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printf("Dumping the internal trie\n"); |
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nat_rewrite_dump(trie); |
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/* now do the matching... */ |
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OSMO_ASSERT(!nat_rewrite_lookup(trie, "")); |
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OSMO_ASSERT(!nat_rewrite_lookup(trie, "2")); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1")->rewrite, "1") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12")->rewrite, "2") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "123")->rewrite, "3") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1234")->rewrite, "4") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12345")->rewrite, "5") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "123456")->rewrite, "6") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1234567")->rewrite, "7") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12345678")->rewrite, "8") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "123456789")->rewrite, "9") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1234567890")->rewrite, "10") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "13")->rewrite, "11") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "14")->rewrite, "12") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "15")->rewrite, "13") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "16")->rewrite, "14") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "823455")->rewrite, "15") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "82")->rewrite, "16") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "+49123445")->rewrite, "17") == 0); |
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|
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/* match a prefix */ |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "121")->rewrite, "2") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1292323")->rewrite, "2") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12345678901")->rewrite, "10") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "160")->rewrite, "14") == 0); |
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OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12345678901123452123123")->rewrite, "10") == 0); |
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|
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/* invalid input */ |
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OSMO_ASSERT(!nat_rewrite_lookup(trie, "12abc")); |
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talloc_free(trie); |
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trie = nat_rewrite_parse(NULL, "does_not_exist.csv"); |
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OSMO_ASSERT(!trie); |
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printf("Done with the tests.\n"); |
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return 0; |
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} |
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@ -0,0 +1,20 @@ |
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Testing the trie |
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Dumping the internal trie |
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1,1 |
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12,2 |
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123,3 |
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1234,4 |
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12345,5 |
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123456,6 |
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1234567,7 |
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12345678,8 |
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123456789,9 |
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1234567890,10 |
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13,11 |
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14,12 |
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15,13 |
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16,14 |
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82,16 |
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823455,15 |
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+49123,17 |
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Done with the tests. |
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Can't render this file because it has a wrong number of fields in line 24.
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Reference in new issue