shadowsocks-libev/src/rule.cpp

/*
 * Copyright (c) 2011 and 2012, Dustin Lundquist <dustin@null-ptr.net>
 * Copyright (c) 2011 Manuel Kasper <mk@neon1.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <string.h>

#include "rule.h"
#include "utils.h"

rule_t *
new_rule()
{
    rule_t *rule;

    rule = (rule_t *)calloc(1, sizeof(rule_t));
    if (rule == NULL) {
        ERROR("malloc");
        return NULL;
    }

    return rule;
}

int
accept_rule_arg(rule_t *rule, const char *arg)
{
    if (rule->pattern == NULL) {
        rule->pattern = strdup(arg);
        if (rule->pattern == NULL) {
            ERROR("strdup failed");
            return -1;
        }
    } else {
        LOGE("Unexpected table rule argument: %s", arg);
        return -1;
    }

    return 1;
}

void
add_rule(struct ss_list *rules, rule_t *rule)
{
    ss_list_add(rules, &rule->entries);
}

int
init_rule(rule_t *rule)
{
    if (strncmp(rule->pattern, "full:", 5) == 0) {
        rule->kind = 1;
        rule->literal = rule->pattern + 5;
    } else if (strncmp(rule->pattern, "suffix:", 7) == 0) {
        rule->kind = 2;
        rule->literal = rule->pattern + 7;
    }
    if (rule->kind != 0) {
        return *rule->literal != '\0' ? 1 : 0;
    }
#if SS_ENABLE_REGEX
    if (rule->pattern_re == NULL) {
        int errcode;
        PCRE2_SIZE erroffset;
        rule->pattern_re = pcre2_compile((PCRE2_SPTR)rule->pattern,
            PCRE2_ZERO_TERMINATED, 0, &errcode, &erroffset, NULL);
        if (rule->pattern_re == NULL) {
            PCRE2_UCHAR errbuf[256];
            pcre2_get_error_message(errcode, errbuf, sizeof(errbuf));
            LOGE("Regex compilation of \"%s\" failed: %s, offset %d",
                 rule->pattern, errbuf, (int)erroffset);
            return 0;
        }
        rule->match_data = pcre2_match_data_create_from_pattern(rule->pattern_re, NULL);
        if (rule->match_data == NULL) {
            pcre2_code_free(rule->pattern_re);
            rule->pattern_re = NULL;
            return 0;
        }
    }
    return 1;
#else
    LOGE("Regex ACL support is disabled; use full:domain or suffix:domain: %s", rule->pattern);
    return -1;
#endif
}

static bool
literal_equal(const char *a, const char *b, size_t length)
{
    for (size_t i = 0; i < length; i++) {
        unsigned char x = (unsigned char)a[i], y = (unsigned char)b[i];
        if (x >= 'A' && x <= 'Z') x += 'a' - 'A';
        if (y >= 'A' && y <= 'Z') y += 'a' - 'A';
        if (x != y) return false;
    }
    return true;
}

rule_t *
lookup_rule(const struct ss_list *rules, const char *name, size_t name_len)
{
    struct ss_list_item *curr, *next;

    if (name == NULL) {
        name     = "";
        name_len = 0;
    }

    for (curr = ss_list_start(rules); !ss_list_is_end(rules, curr);
         curr = next) {
        next = curr->next;
        rule_t *rule = ss_container_of(curr, rule_t, entries);
        if (rule->kind != 0) {
            size_t length = strlen(rule->literal);
            if (name_len >= length &&
                (name_len == length || (rule->kind == 2 && name[name_len - length - 1] == '.')) &&
                literal_equal(name + name_len - length, rule->literal, length)) return rule;
            continue;
        }
#if SS_ENABLE_REGEX
        if (pcre2_match(rule->pattern_re, (PCRE2_SPTR)name,
                        name_len, 0, 0, rule->match_data, NULL) >= 0)
            return rule;
#endif
    }

    return NULL;
}

void
remove_rule(rule_t *rule)
{
    ss_list_remove(&rule->entries);
    free_rule(rule);
}

void
free_rule(rule_t *rule)
{
    if (rule == NULL)
        return;

    ss_free(rule->pattern);
#if SS_ENABLE_REGEX
    if (rule->match_data != NULL)
        pcre2_match_data_free(rule->match_data);
    if (rule->pattern_re != NULL)
        pcre2_code_free(rule->pattern_re);
#endif
    ss_free(rule);
}