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/* Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <sys/socket.h>
#include "common/acl.h"
static inline uint32_t acl_sa_ipv4(sockaddr_t *a) {
return a->addr4.sin_addr.s_addr;
}
static inline uint32_t acl_fill_mask32(short c) {
/*! \todo Consider optimizing using LUT. */
assert(c >= 0 && c <= 32);
unsigned r = 0;
/*! This actually builds big-endian mask
* as we will match against addresses in
* network byte-order (big-endian).
* Otherwise it should be built from
* HO bit -> LO bit.
*/
for (char i = 0; i < c; ++i) {
r |= (1 << i);
}
return r;
}
static int acl_compare(void *k1, void *k2)
{
sockaddr_t* a1 = (sockaddr_t *)k1;
sockaddr_t* a2 = (sockaddr_t *)k2;
/* Check different length, IPv4 goes first. */
int ldiff = a1->len - a2->len;
if (ldiff != 0) {
return ldiff < 0 ? -1 : 1;
}
/* Compare integers if IPv4. */
if (a1->family == AF_INET) {
/* Compute mask .*/
uint32_t mask = acl_fill_mask32(a1->prefix);
/* Compare address. */
int cmp1 = (acl_sa_ipv4(a1) & mask);
int cmp2 = (acl_sa_ipv4(a2) & mask);
if (cmp1 > cmp2) return 1;
if (cmp1 < cmp2) return -1;
return 0;
}
/* IPv6 matching. */
#ifndef DISABLE_IPV6
if (a1->family == AF_INET6) {
/* Get mask .*/
short chunk = a1->prefix;
/* Compare address by 32bit chunks. */
uint32_t* a1p = (uint32_t *)(&a1->addr6.sin6_addr);
uint32_t* a2p = (uint32_t *)(&a2->addr6.sin6_addr);
/* Mask 0 = 0 bits to compare from LO->HO (in big-endian).
* Mask 128 = 128 bits to compare.
*/
while (chunk > 0) {
uint32_t mask = 0xffffffff;
if (chunk > sizeof(mask) << 3) {
chunk -= sizeof(mask) << 3;
} else {
mask = acl_fill_mask32(chunk);
chunk = 0;
}
int cmp1 = (*(a1p++) & mask);
int cmp2 = (*(a2p++) & mask);
if (cmp1 > cmp2) return 1;
if (cmp1 < cmp2) return -1;
}
return 0;
}
#endif
return 0;
}
acl_t *acl_new(acl_rule_t default_rule, const char *name)
{
/* Trailing '\0' for NULL name. */
size_t name_len = 1;
if (name) {
name_len += strlen(name);
} else {
name = "";
}
/* Allocate memory for ACL. */
acl_t* acl = malloc(sizeof(acl_t) + name_len);
if (!acl) {
return 0;
}
/* Initialize skip list. */
acl->rules = skip_create_list(acl_compare);
if (!acl->rules) {
free(acl);
return 0;
}
/* Initialize skip list for rules with TSIG. */
/*! \todo This needs a better structure to make
* nodes with TSIG preferred, but for now
* it will do to sort nodes into two lists.
* (issue #1675)
*/
acl->rules_pref = skip_create_list(acl_compare);
if (!acl->rules_pref) {
skip_destroy_list(&acl->rules, 0, free);
free(acl);
return 0;
}
/* Initialize. */
memcpy(&acl->name, name, name_len);
acl->default_rule = default_rule;
return acl;
}
void acl_delete(acl_t **acl)
{
if ((acl == NULL) || (*acl == NULL)) {
return;
}
/* Truncate rules. */
skip_destroy_list(&(*acl)->rules, 0, free);
skip_destroy_list(&(*acl)->rules_pref, 0, free);
/* Free ACL. */
free(*acl);
*acl = 0;
}
int acl_create(acl_t *acl, const sockaddr_t* addr, acl_rule_t rule, void *val,
unsigned flags)
{
if (!acl || !addr) {
return ACL_ERROR;
}
/* Insert into skip list. */
acl_key_t *key = malloc(sizeof(acl_key_t));
if (key == NULL) {
return ACL_ERROR;
}
memcpy(&key->addr, addr, sizeof(sockaddr_t));
sockaddr_update(&key->addr);
key->rule = rule;
key->val = val;
if (flags & ACL_PREFER) {
skip_insert(acl->rules_pref, &key->addr, key, 0);
} else {
skip_insert(acl->rules, &key->addr, key, 0);
}
return ACL_ACCEPT;
}
int acl_match(acl_t *acl, const sockaddr_t* addr, acl_key_t **key)
{
if (!acl || !addr) {
return ACL_ERROR;
}
acl_key_t *found = skip_find(acl->rules_pref, (void*)addr);
if (found == NULL) {
found = skip_find(acl->rules, (void*)addr);
}
/* Set stored value if exists. */
if (key != NULL) {
*key = found;
}
/* Return appropriate rule. */
if (found == NULL) {
return acl->default_rule;
}
return found->rule;
}
int acl_truncate(acl_t *acl)
{
if (acl == NULL) {
return ACL_ERROR;
}
/* Destroy all rules. */
skip_destroy_list(&acl->rules, 0, free);
skip_destroy_list(&acl->rules_pref, 0, free);
acl->rules = skip_create_list(acl_compare);
acl->rules_pref = skip_create_list(acl_compare);
if (acl->rules == NULL || acl->rules_pref == NULL) {
return ACL_ERROR;
}
return ACL_ACCEPT;
}
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