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/**
* @file mock/dnssrv.c Mock DNS server
*
* Copyright (C) 2010 - 2016 Creytiv.com
*/
#include <string.h>
#include <re.h>
#include "../test.h"
#define DEBUG_MODULE "mock/dnssrv"
#define DEBUG_LEVEL 5
#include <re_dbg.h>
#define LOCAL_PORT 0
static void dns_server_match(struct dns_server *srv, struct list *rrl,
const char *name, uint16_t type)
{
struct dnsrr *rr0 = NULL;
struct le *le;
le = srv->rrl.head;
while (le) {
struct dnsrr *rr = le->data;
le = le->next;
if (type == rr->type && 0==str_casecmp(name, rr->name)) {
if (!rr0)
rr0 = rr;
list_append(rrl, &rr->le_priv, rr);
}
}
/* If rotation is enabled, then rotate multiple entries
in a deterministic way (no randomness please) */
if (srv->rotate && rr0) {
list_unlink(&rr0->le);
list_append(&srv->rrl, &rr0->le, rr0);
}
}
static void decode_dns_query(struct dns_server *srv,
const struct sa *src, struct mbuf *mb)
{
struct list rrl = LIST_INIT;
struct dnshdr hdr;
struct le *le;
char *qname = NULL;
size_t start, end;
uint16_t type, dnsclass;
int err = 0;
start = mb->pos;
end = mb->end;
if (dns_hdr_decode(mb, &hdr) || hdr.qr || hdr.nq != 1) {
DEBUG_WARNING("unable to decode query header\n");
return;
}
err = dns_dname_decode(mb, &qname, start);
if (err) {
DEBUG_WARNING("unable to decode query name\n");
goto out;
}
if (mbuf_get_left(mb) < 4) {
err = EBADMSG;
DEBUG_WARNING("unable to decode query type/class\n");
goto out;
}
type = ntohs(mbuf_read_u16(mb));
dnsclass = ntohs(mbuf_read_u16(mb));
DEBUG_INFO("dnssrv: type=%s query-name='%s'\n",
dns_rr_typename(type), qname);
if (dnsclass == DNS_CLASS_IN) {
dns_server_match(srv, &rrl, qname, type);
}
hdr.qr = true;
hdr.tc = false;
hdr.rcode = DNS_RCODE_OK;
hdr.nq = 1;
hdr.nans = list_count(&rrl);
mb->pos = start;
err = dns_hdr_encode(mb, &hdr);
if (err)
goto out;
mb->pos = end;
DEBUG_INFO("dnssrv: @@ found %u answers for %s\n",
list_count(&rrl), qname);
for (le = rrl.head; le; le = le->next) {
struct dnsrr *rr = le->data;
err = dns_rr_encode(mb, rr, 0, NULL, start);
if (err)
goto out;
}
mb->pos = start;
(void)udp_send(srv->us, src, mb);
out:
list_clear(&rrl);
mem_deref(qname);
}
static void udp_recv(const struct sa *src, struct mbuf *mb, void *arg)
{
struct dns_server *srv = arg;
decode_dns_query(srv, src, mb);
}
static void destructor(void *arg)
{
struct dns_server *srv = arg;
list_flush(&srv->rrl);
mem_deref(srv->us);
}
int dns_server_alloc(struct dns_server **srvp, bool rotate)
{
struct dns_server *srv;
int err;
if (!srvp)
return EINVAL;
srv = mem_zalloc(sizeof(*srv), destructor);
if (!srv)
return ENOMEM;
err = sa_set_str(&srv->addr, "127.0.0.1", LOCAL_PORT);
if (err)
goto out;
err = udp_listen(&srv->us, &srv->addr, udp_recv, srv);
if (err)
goto out;
err = udp_local_get(srv->us, &srv->addr);
if (err)
goto out;
srv->rotate = rotate;
out:
if (err)
mem_deref(srv);
else
*srvp = srv;
return err;
}
int dns_server_add_a(struct dns_server *srv, const char *name, uint32_t addr)
{
struct dnsrr *rr;
int err;
if (!srv || !name)
return EINVAL;
rr = dns_rr_alloc();
if (!rr)
return ENOMEM;
err = str_dup(&rr->name, name);
if (err)
goto out;
rr->type = DNS_TYPE_A;
rr->dnsclass = DNS_CLASS_IN;
rr->ttl = 3600;
rr->rdlen = 0;
rr->rdata.a.addr = addr;
list_append(&srv->rrl, &rr->le, rr);
out:
if (err)
mem_deref(rr);
return err;
}
int dns_server_add_srv(struct dns_server *srv, const char *name,
uint16_t pri, uint16_t weight, uint16_t port,
const char *target)
{
struct dnsrr *rr;
int err;
if (!srv || !name || !port || !target)
return EINVAL;
rr = dns_rr_alloc();
if (!rr)
return ENOMEM;
err = str_dup(&rr->name, name);
if (err)
goto out;
rr->type = DNS_TYPE_SRV;
rr->dnsclass = DNS_CLASS_IN;
rr->ttl = 3600;
rr->rdlen = 0;
rr->rdata.srv.pri = pri;
rr->rdata.srv.weight = weight;
rr->rdata.srv.port = port;
str_dup(&rr->rdata.srv.target, target);
list_append(&srv->rrl, &rr->le, rr);
out:
if (err)
mem_deref(rr);
return err;
}
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