Mirror of :pserver:cvs@cvs.fefe.de:/cvs libowfat https://www.fefe.de/libowfat/
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#include "stralloc.h"
#include "uint16.h"
#include "byte.h"
#include "dns.h"
#include "ip6.h"
static char *q = 0;
int dns_name_packet(stralloc *out,const char *buf,unsigned int len)
{
unsigned int pos;
char header[12];
uint16 numanswers;
uint16 datalen;
if (!stralloc_copys(out,"")) return -1;
pos = dns_packet_copy(buf,len,0,header,12); if (!pos) return -1;
uint16_unpack_big(header + 6,&numanswers);
pos = dns_packet_skipname(buf,len,pos); if (!pos) return -1;
pos += 4;
while (numanswers--) {
pos = dns_packet_skipname(buf,len,pos); if (!pos) return -1;
pos = dns_packet_copy(buf,len,pos,header,10); if (!pos) return -1;
uint16_unpack_big(header + 8,&datalen);
if (byte_equal(header,2,DNS_T_PTR))
if (byte_equal(header + 2,2,DNS_C_IN)) {
if (!dns_packet_getname(buf,len,pos,&q)) return -1;
if (!dns_domain_todot_cat(out,q)) return -1;
return 0;
}
pos += datalen;
}
return 0;
}
int dns_name4(stralloc *out,const char ip[4])
{
char name[DNS_NAME4_DOMAIN];
dns_name4_domain(name,ip);
if (dns_resolve(name,DNS_T_PTR) == -1) return -1;
if (dns_name_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen) == -1) return -1;
dns_transmit_free(&dns_resolve_tx);
dns_domain_free(&q);
return 0;
}
static int dns_name6_inner(stralloc *out,const char ip[16],int t)
{
char name[DNS_NAME6_DOMAIN];
dns_name6_domain(name,ip,t);
if (dns_resolve(name,DNS_T_PTR) == -1) return -1;
if (dns_name_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen) == -1) return -1;
dns_transmit_free(&dns_resolve_tx);
dns_domain_free(&q);
return 0;
}
int dns_name6(stralloc *out,const char ip[16])
{
if (ip6_isv4mapped(ip))
return dns_name4(out,ip+12);
if (dns_name6_inner(out,ip,DNS_IP6_ARPA)) return -1;
if (!out->len) return dns_name6_inner(out,ip,DNS_IP6_INT);
return 0;
}