//databuffer format
//type.mvalue.data.type.mvalue.data...
int
// write_back_to_client(uchar * td, enum rrtype otype, uint8_t level, ushort id, int dlen,
write_back_to_client(mbuf_type *mbuf, uchar * fr, int vlen)
{
struct setheader sh = { 0 }; //data in dns header
int main_val = 0, dnslen = 0;
uchar *msg = mbuf->buf, type; //if bigger, use TCP
uchar *from = fr, *to = msg;
struct mvalue *mv = NULL;
int jump = 0;
uint16_t temp = 0;
struct hlpc hlp[100]; //p domians to compression
hlp[0].name = mbuf->td;
hlp[0].off = sizeof(dnsheader);
hlp[0].level = mbuf->lowerdomain.label_count;
hlp[0].ref = -1;
hlp[0].mt = 0;
hlp[0].len = mbuf->dlen;
if (mbuf->dlen == 2) // root
jump = sizeof(dnsheader) + 1 + sizeof(qdns);
else
jump = sizeof(dnsheader) + mbuf->dlen + sizeof(qdns);
to = to + jump;
while (vlen > 1) //vlen include type.mvalue.data.
{
type = from[0];
mv = (struct mvalue *)(from + 1);
to = fill_rrset_in_msg(hlp, from, to, &main_val, msg);
if (to == NULL)
return -1;
// *to = 0;
vlen = vlen - 1 - mv->len - sizeof(struct mvalue);
sh.an += mv->num;
from = from + mv->len + 1 + sizeof(struct mvalue); // type.mv.len.
/**
* if previous record is CNAME(query type can't be ANY, that we don't support now),
* next A & AAAA & CNAME use previous domain name (cname name).
* We duplicate here to make it possible to refer previous one.
*/
if (type == CNAME && vlen > 1 /*&& mbuf->qtype != ANY*/ && (from[0] == A || from[0] == AAAA || from[0] == CNAME))
{
main_val++;
hlp[main_val].name = hlp[main_val - 1].name;
hlp[main_val].off = hlp[main_val - 1].off;
hlp[main_val].level = hlp[main_val - 1].level;
hlp[main_val].len = hlp[main_val - 1].len;
hlp[main_val].ref = -1;
hlp[main_val].mt = 0;
}
}
sh.itor = msg;
sh.dlen = (mbuf->dlen == 2) ? 1: (mbuf->dlen);
sh.od = mbuf->td;
sh.id = mbuf->id;
sh.type = mbuf->qtype;
fill_header_in_msg(&sh);
dnslen = to - msg;
mbuf->buflen = dnslen;
mbuf->addr = &(mbuf->caddr);
if (mbuf->socktype == UDP) {
if (dnslen > MAX_UDP_SIZE)
send_tc_to_client(mbuf);
else
udp_write_info(mbuf, 0); //ignore send error
} else {
temp = DNS_GET16(dnslen);
memcpy(msg - 2, &temp, sizeof(uint16_t));
mbuf->buflen = dnslen + 2;
mbuf->buf = msg - 2;
tcp_write_info(mbuf, 0);
}
////////////////////////////////////////////////////////////
//key, val, vallen, ttl offset
//if now + TTL_UPDATE > ttl
//return
/* ret = transfer_record_to_msg(msgto, td, msg + 2, dnslen, ttloff); */
/* if (ret < 0) */
/* return -1; */
return 0;
}
//return 0,continue
//return idx > 0,delete and release qoutinfo
//return < 0,error,nothing
//0 is a valid idx,but it has a special meaning.
//so we return idx + 1. and use it minus 1
int
passer_auth_data(struct author *author, uchar * buf, struct sockinfo *si)
{
int idx, ret, pret;
mbuf_type *mbuf = NULL;
ushort xtype = 0;
dnsheader *hdr = (dnsheader *) buf;
packet_type lowerdomain;
//msg buffer
ret = check_enter(author, buf, &idx, &mbuf, &lowerdomain);
mbuf_free(si->mbuf);
si->mbuf = mbuf;
//we get tc and do NOT update id
//because some bad servers always return tc
//thus we has chance to get another answers
//then close tcp immediately, and send nothing
if (ret == -2) //tc,use tcp.
return -idx - 1;
if (ret == 0) //late msg,server refused,continue
return 0;
if (ret == -1) //error msg, delete qoutinfo
return idx + 1;
mbuf->mxtry--;
if (ret == -3) //format error, server refused, error...
{
mbuf->qtimes++;
return 0;
}
si->lowerdomain = &lowerdomain;
pret = passer_related_data(si, mbuf, author);
if (pret < 0)
return 0; //error msg,continue
mbuf->fd = author->s->ludp;
mbuf->addr = &(mbuf->caddr);
if (pret == CNAME && mbuf->qtype == CNAME) {
if (mbuf->fd != -1) {
*(ushort *) buf = mbuf->cid;
mbuf->buf = buf;
mbuf->buflen = si->buflen;
if (si->buflen > MAX_UDP_SIZE)
send_tc_to_client(mbuf);
else {
udp_write_info(mbuf, 0); //cname..
write_log(author->loginfo, author->idx,
mbuf->td, mbuf->dlen, mbuf->qtype, mbuf->addr);
}
}
return idx + 1;
}
if (pret == CNAME || mbuf->qname != Q_DOMAIN) {
mbuf->stat = PROCESS_QUERY;
mbuf->socktype = UDP; //if prev we use tcp, use udp again
return 0;
}
if ((pret == SOA) || (ntohs(hdr->ancount) > 0)) {
if (mbuf->fd != -1) {
if (mbuf->hascname == 0) {
*(ushort *) buf = mbuf->cid; //no need to htons
mbuf->buf = buf;
mbuf->buflen = si->buflen;
if (si->buflen > MAX_UDP_SIZE)
send_tc_to_client(mbuf);
else {
udp_write_info(mbuf, 0);
write_log(author->loginfo,
author->idx, mbuf->td, mbuf->dlen, mbuf->qtype,
mbuf->addr);
}
} else //has a cname,put the origin domain first
{
if (pret == SOA) {
xtype = CNAME;
}
else
xtype = mbuf->qtype;
ret =
find_record_from_mem(mbuf->td, mbuf->dlen, xtype,
author->s->datasets,
author->tmpbuffer,
author->databuffer,
&(mbuf->lowerdomain.hash[0]));
if (ret > 0) {
author->response++;
if (mbuf->fd != -1) {
mbuf->buf = mbuf->data + 2;
write_back_to_client(mbuf, author->databuffer, ret);
}
write_log(author->loginfo, author->idx, mbuf->td, mbuf->dlen, mbuf->qtype, mbuf->addr);
}
}
}
//else printf("update record\n");
return idx + 1;
}
mbuf->stat = PROCESS_QUERY; //no need to find_addr in launch_new_qu
mbuf->socktype = UDP;
return 0;
}
//databuffer format
//type.mvalue.data.type.mvalue.data...
int
// write_back_to_client(uchar * td, enum rrtype otype, uint8_t level, ushort id, int dlen,
write_back_to_client(mbuf_type *mbuf, uchar * fr, int vlen)
{
struct setheader sh = { 0 }; //data in dns header
int main_val = 0, dnslen = 0;
uchar *msg = mbuf->buf, type; //if bigger, use TCP
uchar *from = fr, *to = msg;
struct mvalue *mv = NULL;
int jump = 0;
uint16_t temp = 0;
struct hlpc hlp[100]; //p domians to compression
hlp[0].name = mbuf->td;
hlp[0].off = sizeof(dnsheader);
hlp[0].level = mbuf->lowerdomain.label_count;
hlp[0].ref = -1;
hlp[0].mt = 0;
hlp[0].len = mbuf->dlen;
jump = sizeof(dnsheader) + mbuf->dlen + sizeof(qdns);
to = to + jump;
while (vlen > 1) //vlen include type.mvalue.data.
{
type = from[0];
mv = (struct mvalue *)(from + 1);
to = fill_rrset_in_msg(hlp, from, to, main_val, msg);
if (to == NULL)
return -1;
// *to = 0;
vlen = vlen - 1 - mv->len - sizeof(struct mvalue);
sh.an += mv->num;
if (type == CNAME) //cname must be 1
main_val++; //no all rdata is the cname's
from = from + mv->len + 1 + sizeof(struct mvalue); // type.mv.len.
}
sh.itor = msg;
sh.dlen = mbuf->dlen;
sh.od = mbuf->td;
sh.id = mbuf->id;
sh.type = mbuf->qtype;
fill_header_in_msg(&sh);
dnslen = to - msg;
mbuf->buflen = dnslen;
mbuf->addr = &(mbuf->caddr);
if (mbuf->socktype == UDP) {
if (dnslen > MAX_UDP_SIZE)
send_tc_to_client(mbuf);
else
udp_write_info(mbuf, 0); //ignore send error
} else {
temp = DNS_GET16(dnslen);
memcpy(msg - 2, &temp, sizeof(uint16_t));
mbuf->buflen = dnslen + 2;
mbuf->buf = msg - 2;
tcp_write_info(mbuf, 0);
}
////////////////////////////////////////////////////////////
//key, val, vallen, ttl offset
//if now + TTL_UPDATE > ttl
//return
/* ret = transfer_record_to_msg(msgto, td, msg + 2, dnslen, ttloff); */
/* if (ret < 0) */
/* return -1; */
return 0;
}
