/*
* iterator/iter_fwd.c - iterative resolver module forward zones.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* 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.
*/
/**
* \file
*
* This file contains functions to assist the iterator module.
* Keep track of forward zones and config settings.
*/
#include "config.h"
#include "iterator/iter_fwd.h"
#include "iterator/iter_delegpt.h"
#include "util/log.h"
#include "util/config_file.h"
#include "util/net_help.h"
#include "util/data/dname.h"
#include "ldns/rrdef.h"
#include "ldns/str2wire.h"
int
fwd_cmp(const void* k1, const void* k2)
{
int m;
struct iter_forward_zone* n1 = (struct iter_forward_zone*)k1;
struct iter_forward_zone* n2 = (struct iter_forward_zone*)k2;
if(n1->dclass != n2->dclass) {
if(n1->dclass < n2->dclass)
return -1;
return 1;
}
return dname_lab_cmp(n1->name, n1->namelabs, n2->name, n2->namelabs,
&m);
}
struct iter_forwards*
forwards_create(void)
{
struct iter_forwards* fwd = (struct iter_forwards*)calloc(1,
sizeof(struct iter_forwards));
if(!fwd)
return NULL;
return fwd;
}
static void fwd_zone_free(struct iter_forward_zone* n)
{
if(!n) return;
delegpt_free_mlc(n->dp);
free(n->name);
free(n);
}
static void delfwdnode(rbnode_t* n, void* ATTR_UNUSED(arg))
{
struct iter_forward_zone* node = (struct iter_forward_zone*)n;
fwd_zone_free(node);
}
static void fwd_del_tree(struct iter_forwards* fwd)
{
if(fwd->tree)
traverse_postorder(fwd->tree, &delfwdnode, NULL);
free(fwd->tree);
}
void
forwards_delete(struct iter_forwards* fwd)
{
if(!fwd)
return;
fwd_del_tree(fwd);
free(fwd);
}
/** insert info into forward structure */
static int
forwards_insert_data(struct iter_forwards* fwd, uint16_t c, uint8_t* nm,
size_t nmlen, int nmlabs, struct delegpt* dp)
{
struct iter_forward_zone* node = (struct iter_forward_zone*)malloc(
sizeof(struct iter_forward_zone));
if(!node) {
delegpt_free_mlc(dp);
return 0;
}
node->node.key = node;
node->dclass = c;
node->name = memdup(nm, nmlen);
if(!node->name) {
delegpt_free_mlc(dp);
free(node);
return 0;
}
node->namelen = nmlen;
node->namelabs = nmlabs;
node->dp = dp;
if(!rbtree_insert(fwd->tree, &node->node)) {
char buf[257];
dname_str(nm, buf);
log_err("duplicate forward zone %s ignored.", buf);
delegpt_free_mlc(dp);
free(node->name);
free(node);
}
return 1;
}
/** insert new info into forward structure given dp */
static int
forwards_insert(struct iter_forwards* fwd, uint16_t c, struct delegpt* dp)
{
return forwards_insert_data(fwd, c, dp->name, dp->namelen,
dp->namelabs, dp);
}
/** initialise parent pointers in the tree */
static void
fwd_init_parents(struct iter_forwards* fwd)
{
struct iter_forward_zone* node, *prev = NULL, *p;
int m;
RBTREE_FOR(node, struct iter_forward_zone*, fwd->tree) {
node->parent = NULL;
if(!prev || prev->dclass != node->dclass) {
prev = node;
continue;
}
(void)dname_lab_cmp(prev->name, prev->namelabs, node->name,
node->namelabs, &m); /* we know prev is smaller */
/* sort order like: . com. bla.com. zwb.com. net. */
/* find the previous, or parent-parent-parent */
for(p = prev; p; p = p->parent)
/* looking for name with few labels, a parent */
if(p->namelabs <= m) {
/* ==: since prev matched m, this is closest*/
/* <: prev matches more, but is not a parent,
* this one is a (grand)parent */
node->parent = p;
break;
}
prev = node;
}
}
/** set zone name */
static struct delegpt*
read_fwds_name(struct config_stub* s)
{
struct delegpt* dp;
uint8_t* dname;
size_t dname_len;
if(!s->name) {
log_err("forward zone without a name (use name \".\" to forward everything)");
return NULL;
}
dname = sldns_str2wire_dname(s->name, &dname_len);
if(!dname) {
log_err("cannot parse forward zone name %s", s->name);
return NULL;
}
if(!(dp=delegpt_create_mlc(dname))) {
free(dname);
log_err("out of memory");
return NULL;
}
free(dname);
return dp;
}
/** set fwd host names */
static int
read_fwds_host(struct config_stub* s, struct delegpt* dp)
{
struct config_strlist* p;
uint8_t* dname;
size_t dname_len;
for(p = s->hosts; p; p = p->next) {
log_assert(p->str);
dname = sldns_str2wire_dname(p->str, &dname_len);
if(!dname) {
log_err("cannot parse forward %s server name: '%s'",
s->name, p->str);
return 0;
}
if(!delegpt_add_ns_mlc(dp, dname, 0)) {
free(dname);
log_err("out of memory");
return 0;
}
free(dname);
}
return 1;
}
/** set fwd server addresses */
static int
read_fwds_addr(struct config_stub* s, struct delegpt* dp)
{
struct config_strlist* p;
struct sockaddr_storage addr;
socklen_t addrlen;
for(p = s->addrs; p; p = p->next) {
log_assert(p->str);
if(!extstrtoaddr(p->str, &addr, &addrlen)) {
log_err("cannot parse forward %s ip address: '%s'",
s->name, p->str);
return 0;
}
if(!delegpt_add_addr_mlc(dp, &addr, addrlen, 0, 0)) {
log_err("out of memory");
return 0;
}
}
return 1;
}
/** read forwards config */
static int
read_forwards(struct iter_forwards* fwd, struct config_file* cfg)
{
struct config_stub* s;
for(s = cfg->forwards; s; s = s->next) {
struct delegpt* dp;
if(!(dp=read_fwds_name(s)))
return 0;
if(!read_fwds_host(s, dp) || !read_fwds_addr(s, dp)) {
delegpt_free_mlc(dp);
return 0;
}
/* set flag that parent side NS information is included.
* Asking a (higher up) server on the internet is not useful */
/* the flag is turned off for 'forward-first' so that the
* last resort will ask for parent-side NS record and thus
* fallback to the internet name servers on a failure */
dp->has_parent_side_NS = (uint8_t)!s->isfirst;
verbose(VERB_QUERY, "Forward zone server list:");
delegpt_log(VERB_QUERY, dp);
if(!forwards_insert(fwd, LDNS_RR_CLASS_IN, dp))
return 0;
}
return 1;
}
/** insert a stub hole (if necessary) for stub name */
static int
fwd_add_stub_hole(struct iter_forwards* fwd, uint16_t c, uint8_t* nm)
{
struct iter_forward_zone key;
key.node.key = &key;
key.dclass = c;
key.name = nm;
key.namelabs = dname_count_size_labels(key.name, &key.namelen);
return forwards_insert_data(fwd, key.dclass, key.name,
key.namelen, key.namelabs, NULL);
}
/** make NULL entries for stubs */
static int
make_stub_holes(struct iter_forwards* fwd, struct config_file* cfg)
{
struct config_stub* s;
uint8_t* dname;
size_t dname_len;
for(s = cfg->stubs; s; s = s->next) {
dname = sldns_str2wire_dname(s->name, &dname_len);
if(!dname) {
log_err("cannot parse stub name '%s'", s->name);
return 0;
}
if(!fwd_add_stub_hole(fwd, LDNS_RR_CLASS_IN, dname)) {
free(dname);
log_err("out of memory");
return 0;
}
free(dname);
}
return 1;
}
int
forwards_apply_cfg(struct iter_forwards* fwd, struct config_file* cfg)
{
fwd_del_tree(fwd);
fwd->tree = rbtree_create(fwd_cmp);
if(!fwd->tree)
return 0;
/* read forward zones */
if(!read_forwards(fwd, cfg))
return 0;
if(!make_stub_holes(fwd, cfg))
return 0;
fwd_init_parents(fwd);
return 1;
}
struct delegpt*
forwards_find(struct iter_forwards* fwd, uint8_t* qname, uint16_t qclass)
{
rbnode_t* res = NULL;
struct iter_forward_zone key;
key.node.key = &key;
key.dclass = qclass;
key.name = qname;
key.namelabs = dname_count_size_labels(qname, &key.namelen);
res = rbtree_search(fwd->tree, &key);
if(res) return ((struct iter_forward_zone*)res)->dp;
return NULL;
}
struct delegpt*
forwards_lookup(struct iter_forwards* fwd, uint8_t* qname, uint16_t qclass)
{
/* lookup the forward zone in the tree */
rbnode_t* res = NULL;
struct iter_forward_zone *result;
struct iter_forward_zone key;
key.node.key = &key;
key.dclass = qclass;
key.name = qname;
key.namelabs = dname_count_size_labels(qname, &key.namelen);
if(rbtree_find_less_equal(fwd->tree, &key, &res)) {
/* exact */
result = (struct iter_forward_zone*)res;
} else {
/* smaller element (or no element) */
int m;
result = (struct iter_forward_zone*)res;
if(!result || result->dclass != qclass)
return NULL;
/* count number of labels matched */
(void)dname_lab_cmp(result->name, result->namelabs, key.name,
key.namelabs, &m);
while(result) { /* go up until qname is subdomain of stub */
if(result->namelabs <= m)
break;
result = result->parent;
}
}
if(result)
return result->dp;
return NULL;
}
struct delegpt*
forwards_lookup_root(struct iter_forwards* fwd, uint16_t qclass)
{
uint8_t root = 0;
return forwards_lookup(fwd, &root, qclass);
}
int
forwards_next_root(struct iter_forwards* fwd, uint16_t* dclass)
{
struct iter_forward_zone key;
rbnode_t* n;
struct iter_forward_zone* p;
if(*dclass == 0) {
/* first root item is first item in tree */
n = rbtree_first(fwd->tree);
if(n == RBTREE_NULL)
return 0;
p = (struct iter_forward_zone*)n;
if(dname_is_root(p->name)) {
*dclass = p->dclass;
return 1;
}
/* root not first item? search for higher items */
*dclass = p->dclass + 1;
return forwards_next_root(fwd, dclass);
}
/* find class n in tree, we may get a direct hit, or if we don't
* this is the last item of the previous class so rbtree_next() takes
* us to the next root (if any) */
key.node.key = &key;
key.name = (uint8_t*)"\000";
key.namelen = 1;
key.namelabs = 0;
key.dclass = *dclass;
n = NULL;
if(rbtree_find_less_equal(fwd->tree, &key, &n)) {
/* exact */
return 1;
} else {
/* smaller element */
if(!n || n == RBTREE_NULL)
return 0; /* nothing found */
n = rbtree_next(n);
if(n == RBTREE_NULL)
return 0; /* no higher */
p = (struct iter_forward_zone*)n;
if(dname_is_root(p->name)) {
*dclass = p->dclass;
return 1;
}
/* not a root node, return next higher item */
*dclass = p->dclass+1;
return forwards_next_root(fwd, dclass);
}
}
size_t
forwards_get_mem(struct iter_forwards* fwd)
{
struct iter_forward_zone* p;
size_t s;
if(!fwd)
return 0;
s = sizeof(*fwd) + sizeof(*fwd->tree);
RBTREE_FOR(p, struct iter_forward_zone*, fwd->tree) {
s += sizeof(*p) + p->namelen + delegpt_get_mem(p->dp);
}
return s;
}
static struct iter_forward_zone*
fwd_zone_find(struct iter_forwards* fwd, uint16_t c, uint8_t* nm)
{
struct iter_forward_zone key;
key.node.key = &key;
key.dclass = c;
key.name = nm;
key.namelabs = dname_count_size_labels(nm, &key.namelen);
return (struct iter_forward_zone*)rbtree_search(fwd->tree, &key);
}
int
forwards_add_zone(struct iter_forwards* fwd, uint16_t c, struct delegpt* dp)
{
struct iter_forward_zone *z;
if((z=fwd_zone_find(fwd, c, dp->name)) != NULL) {
(void)rbtree_delete(fwd->tree, &z->node);
fwd_zone_free(z);
}
if(!forwards_insert(fwd, c, dp))
return 0;
fwd_init_parents(fwd);
return 1;
}
void
forwards_delete_zone(struct iter_forwards* fwd, uint16_t c, uint8_t* nm)
{
struct iter_forward_zone *z;
if(!(z=fwd_zone_find(fwd, c, nm)))
return; /* nothing to do */
(void)rbtree_delete(fwd->tree, &z->node);
fwd_zone_free(z);
fwd_init_parents(fwd);
}
int
forwards_add_stub_hole(struct iter_forwards* fwd, uint16_t c, uint8_t* nm)
{
if(!fwd_add_stub_hole(fwd, c, nm)) {
return 0;
}
fwd_init_parents(fwd);
return 1;
}
void
forwards_delete_stub_hole(struct iter_forwards* fwd, uint16_t c, uint8_t* nm)
{
struct iter_forward_zone *z;
if(!(z=fwd_zone_find(fwd, c, nm)))
return; /* nothing to do */
if(z->dp != NULL)
return; /* not a stub hole */
(void)rbtree_delete(fwd->tree, &z->node);
fwd_zone_free(z);
fwd_init_parents(fwd);
}