void DnsQuery(PCHAR pDomain, UCHAR iType, UCHAR iBankOffset, USHORT sCallBackAddr)
{
UCHAR i;
DNS_HANDLE pDcb;
pDcb = _pDcbData;
for (i = 0; i < DNS_CB_TSIZE; i ++)
{
if(pDcb->iState == DS_RESOLVED && iType == pDcb->iType)
{
// this should be a case insensitive string compare
if (!strcmp(pDomain, pDcb->pName))
{
// domain name alreay resolved
TaskDnsDone(pDcb->pAnswer, sCallBackAddr, iBankOffset);
return;
}
}
pDcb ++;
}
pDcb = dns_alloc();
if (pDcb)
{
dns_save_send(pDcb, pDomain, sCallBackAddr, iBankOffset, iType);
}
else
{
dns_failed(sCallBackAddr, iBankOffset);
}
}
static char *dns_str_from_rdata( const unsigned char *rdata )
{
char *str;
unsigned int len = rdata[0];
str = dns_alloc( len + 1 );
if (str)
{
memcpy( str, ++rdata, len );
str[len] = '\0';
}
return str;
}
static char *dns_dname_from_msg( ns_msg msg, const unsigned char *pos )
{
int len;
char *str, dname[NS_MAXDNAME] = ".";
/* returns *compressed* length, ignore it */
len = dns_ns_name_uncompress( ns_msg_base( msg ), ns_msg_end( msg ),
pos, dname, sizeof(dname) );
len = strlen( dname );
str = dns_alloc( len + 1 );
if (str) strcpy( str, dname );
return str;
}
struct dnspkt *
dns_extractpkt(const unsigned char *buf, int len)
{
u_int16_t qdcount, ancount, remain, *offsets, i, j, off;
const unsigned char *ptr;
struct dnspkt *pkt;
struct rr *rrp;
struct ns_answer_header *nsh;
if (len < 17)
return NULL;
pkt = dns_alloc();
struct ns_transaction_header *nsth=
(struct ns_transaction_header*)buf;
pkt->id = ntohs(nsth->tid);
qdcount = ntohs(nsth->questions);
ancount = ntohs(nsth->answers);
offsets = malloc(qdcount * 4);
ptr = buf + sizeof(struct ns_transaction_header);
remain = len - sizeof(struct ns_transaction_header);
i = 0;
while (qdcount--)
{
offsets[i++] = ptr - buf;
rrp = _new_listitem(&pkt->query);
rrp->data = decompress_label((char*)buf, len, (char*)ptr);
if (!rrp->data)
{
syslog(LOG_ERR, "dns_extractpkt: decompress_label choked in qd\n");
free(offsets);
dns_free(pkt);
return NULL;
}
rrp->len = strlen(rrp->data)+1;
ptr = _skip_lbl(ptr, &remain);
if (!ptr)
{
syslog(LOG_ERR, "dns_extractpkt: _skip_lbl choked in qd\n");
free(offsets);
dns_free(pkt);
return NULL;
}
ptr += 4;
remain -= 4;
}
while (ancount--)
{
rrp = _new_listitem(&pkt->answer);
rrp->link = -1;
if ((ptr[0] & 0xc0) == 0xc0)
{
off = (ptr[0] & ~(0xc0)) * 256 + ptr[1];
for (j = 0; j < i; j++)
if (offsets[j] == off)
break;
if (j < i)
rrp->link = j;
}
ptr=_skip_lbl(ptr,&remain);
nsh=(struct ns_answer_header *)ptr;
ptr+=sizeof(struct ns_answer_header);
remain-=sizeof(struct ns_answer_header);
//printf("REMAIN=%u, datalen=%u, type= 0x%02x, sizeof ns_answer_header=%u\n",remain,ntohs(nsh->datalen), ntohs(nsh->type),sizeof(struct ns_answer_header));
if (ntohs(nsh->type) != NSTYPE_TXT){
ptr+=ntohs(nsh->datalen);
remain-=ntohs(nsh->datalen);
continue;
}
rrp->len = ntohs(nsh->datalen);
rrp->data = malloc(rrp->len);
memcpy(rrp->data, ptr,rrp->len);
remain -= rrp->len;
ptr += rrp->len;
}
return(pkt);
}
