solanum/ircd/dns.c

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/*
* dns.c: An interface to the resolver module in authd
* (based somewhat on ircd-ratbox dns.c)
*
* Copyright (C) 2005 Aaron Sethman <androsyn@ratbox.org>
* Copyright (C) 2005-2012 ircd-ratbox development team
* Copyright (C) 2016 William Pitcock <nenolod@dereferenced.org>
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
* USA
*/
#include "stdinc.h"
#include "rb_lib.h"
#include "client.h"
#include "ircd_defs.h"
#include "parse.h"
#include "dns.h"
#include "match.h"
#include "logger.h"
#include "s_conf.h"
#include "client.h"
#include "send.h"
#include "numeric.h"
#include "msg.h"
#include "hash.h"
#define DNS_HOST_IPV4 ((char)'4')
#define DNS_HOST_IPV6 ((char)'6')
#define DNS_REVERSE_IPV4 ((char)'R')
#define DNS_REVERSE_IPV6 ((char)'S')
static void submit_dns(uint32_t uid, char type, const char *addr);
static void submit_dns_stat(uint32_t uid);
struct dnsreq
{
DNSCB callback;
void *data;
};
struct dnsstatreq
{
DNSLISTCB callback;
void *data;
};
/* These serve as a form of sparse array */
static rb_dictionary *query_dict;
static rb_dictionary *stat_dict;
rb_dlink_list nameservers;
static uint32_t query_id = 0;
static uint32_t stat_id = 0;
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static inline uint32_t
assign_id(uint32_t *id)
{
if(++(*id) == 0)
*id = 1;
return *id;
}
static void
handle_dns_failure(uint32_t xid)
{
struct dnsreq *req = rb_dictionary_retrieve(query_dict, RB_UINT_TO_POINTER(xid));
s_assert(req);
if(req->callback == NULL)
return;
req->callback("FAILED", 0, 0, req->data);
req->callback = NULL;
req->data = NULL;
}
static void
handle_dns_stat_failure(uint32_t xid)
{
struct dnsstatreq *req = rb_dictionary_retrieve(stat_dict, RB_UINT_TO_POINTER(xid));
s_assert(req);
if(req->callback == NULL)
return;
req->callback(1, NULL, 2, req->data);
req->callback = NULL;
req->data = NULL;
}
void
cancel_lookup(uint32_t xid)
{
struct dnsreq *req = rb_dictionary_retrieve(query_dict, RB_UINT_TO_POINTER(xid));
s_assert(req);
req->callback = NULL;
req->data = NULL;
}
void
cancel_dns_stats(uint32_t xid)
{
struct dnsstatreq *req = rb_dictionary_retrieve(stat_dict, RB_UINT_TO_POINTER(xid));
s_assert(req);
req->callback = NULL;
req->data = NULL;
}
uint32_t
lookup_hostname(const char *hostname, int aftype, DNSCB callback, void *data)
{
struct dnsreq *req = rb_malloc(sizeof(struct dnsreq));
int aft;
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uint32_t rid = assign_id(&query_id);
check_authd();
rb_dictionary_add(query_dict, RB_UINT_TO_POINTER(rid), req);
req->callback = callback;
req->data = data;
#ifdef RB_IPV6
if(aftype == AF_INET6)
aft = 6;
else
#endif
aft = 4;
submit_dns(rid, aft == 4 ? DNS_HOST_IPV4 : DNS_HOST_IPV6, hostname);
return (rid);
}
uint32_t
lookup_ip(const char *addr, int aftype, DNSCB callback, void *data)
{
struct dnsreq *req = rb_malloc(sizeof(struct dnsreq));
int aft;
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uint32_t rid = assign_id(&query_id);
check_authd();
rb_dictionary_add(query_dict, RB_UINT_TO_POINTER(rid), req);
req->callback = callback;
req->data = data;
#ifdef RB_IPV6
if(aftype == AF_INET6)
aft = 6;
else
#endif
aft = 4;
submit_dns(rid, aft == 4 ? DNS_REVERSE_IPV4 : DNS_REVERSE_IPV6, addr);
return (rid);
}
static uint32_t
get_nameservers(DNSLISTCB callback, void *data)
{
struct dnsstatreq *req = rb_malloc(sizeof(struct dnsstatreq));
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uint32_t qid = assign_id(&stat_id);
check_authd();
rb_dictionary_add(stat_dict, RB_UINT_TO_POINTER(qid), req);
req->callback = callback;
req->data = data;
submit_dns_stat(qid);
return (qid);
}
void
dns_results_callback(const char *callid, const char *status, const char *type, const char *results)
{
struct dnsreq *req;
uint32_t rid;
int st;
int aft;
long lrid = strtol(callid, NULL, 16);
if(lrid > UINT32_MAX)
return;
rid = (uint32_t)lrid;
req = rb_dictionary_retrieve(query_dict, RB_UINT_TO_POINTER(rid));
if(req == NULL)
return;
st = (*status == 'O');
aft = *type == '6' || *type == 'S' ? 6 : 4;
if(req->callback == NULL)
{
/* got cancelled..oh well */
req->data = NULL;
return;
}
#ifdef RB_IPV6
if(aft == 6)
aft = AF_INET6;
else
#endif
aft = AF_INET;
req->callback(results, st, aft, req->data);
rb_free(req);
rb_dictionary_delete(query_dict, RB_UINT_TO_POINTER(rid));
}
void
dns_stats_results_callback(const char *callid, const char *status, int resc, const char *resv[])
{
struct dnsstatreq *req;
uint32_t qid;
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int st;
long lqid = strtol(callid, NULL, 16);
if(lqid > UINT32_MAX)
return;
qid = (uint32_t)lqid;
req = rb_dictionary_retrieve(stat_dict, RB_UINT_TO_POINTER(qid));
s_assert(req);
if(req->callback == NULL)
{
req->data = NULL;
return;
}
switch(*status)
{
case 'Y':
st = 0;
break;
case 'X':
/* Error */
st = 1;
break;
default:
/* Shouldn't happen... */
return;
}
/* Query complete */
req->callback(resc, resv, st, req->data);
rb_free(req);
rb_dictionary_delete(stat_dict, RB_UINT_TO_POINTER(qid));
}
static void
stats_results_callback(int resc, const char *resv[], int status, void *data)
{
if(status == 0)
{
rb_dlink_node *n, *tn;
RB_DLINK_FOREACH_SAFE(n, tn, nameservers.head)
{
/* Clean up old nameservers */
rb_free(n->data);
rb_dlinkDestroy(n, &nameservers);
}
for(int i = 0; i < resc; i++)
rb_dlinkAddAlloc(rb_strdup(resv[i]), &nameservers);
}
else
{
const char *error = resc ? resv[resc] : "Unknown error";
iwarn("Error getting DNS servers: %s", error);
}
}
void
init_dns(void)
{
query_dict = rb_dictionary_create("dns queries", rb_uint32cmp);
stat_dict = rb_dictionary_create("dns stat queries", rb_uint32cmp);
(void)get_nameservers(stats_results_callback, NULL);
}
void
reload_nameservers(void)
{
check_authd();
rb_helper_write(authd_helper, "R D");
(void)get_nameservers(stats_results_callback, NULL);
}
static void
submit_dns(uint32_t nid, char type, const char *addr)
{
if(authd_helper == NULL)
{
handle_dns_failure(nid);
return;
}
rb_helper_write(authd_helper, "D %x %c %s", nid, type, addr);
}
static void
submit_dns_stat(uint32_t nid)
{
if(authd_helper == NULL)
{
handle_dns_stat_failure(nid);
return;
}
rb_helper_write(authd_helper, "S %x D", nid);
}