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#include "platform.h"
#include "gnunet-dns-parser.h"
#include "gnunet-vpn-packet.h"
unsigned int parse_dns_name(unsigned char* d, const unsigned char* src, unsigned short idx) {/*{{{*/
unsigned char* dest = d;
int len = src[idx++];
while (len != 0) {
if (len & 0xC0) { /* Compressed name, offset in this and the next octet */
unsigned short offset = ((len & 0x3F) << 8) | src[idx++];
parse_dns_name(dest, src, offset - 12); /* 12 for the Header of the DNS-Packet, idx starts at 0 which is 12 bytes from the start of the packet */
return idx;
}
memcpy(dest, src+idx, len);
idx += len;
dest += len;
*dest = '.';
dest++;
len = src[idx++];
};
*dest = 0;
return idx;
}
/*}}}*/
unsigned short parse_dns_record(unsigned char* data, struct dns_record** dst, unsigned short count, unsigned short idx) {/*{{{*/
int i;
unsigned short _idx;
for (i = 0; i < count; i++) {
dst[i] = GNUNET_malloc(sizeof(struct dns_record));
dst[i]->name = alloca(255); // see RFC1035
unsigned char* name = dst[i]->name;
_idx = parse_dns_name(name, data, idx);
dst[i]->namelen = _idx - idx;
idx = _idx;
dst[i]->type = *((unsigned short*)(data+idx));
idx += 2;
dst[i]->class = *((unsigned short*)(data+idx));
idx += 2;
dst[i]->ttl = *((unsigned int*)(data+idx));
idx += 4;
dst[i]->data_len = *((unsigned short*)(data+idx));
idx += 2;
dst[i]->data = GNUNET_malloc(ntohs(dst[i]->data_len));
memcpy(dst[i]->data, data+idx, ntohs(dst[i]->data_len));
idx += ntohs(dst[i]->data_len);
}
return idx;
}/*}}}*/
struct dns_pkt_parsed* parse_dns_packet(struct dns_pkt* pkt) {
struct dns_pkt_parsed* ppkt = GNUNET_malloc(sizeof(struct dns_pkt_parsed));
memcpy(&ppkt->s, &pkt->s, sizeof pkt->s);
unsigned short qdcount = ntohs(ppkt->s.qdcount);
unsigned short ancount = ntohs(ppkt->s.ancount);
unsigned short nscount = ntohs(ppkt->s.nscount);
unsigned short arcount = ntohs(ppkt->s.arcount);
ppkt->queries = GNUNET_malloc(qdcount*sizeof(struct dns_query*));
ppkt->answers = GNUNET_malloc(ancount*sizeof(struct dns_record*));
ppkt->nameservers = GNUNET_malloc(nscount*sizeof(struct dns_record*));
ppkt->additional = GNUNET_malloc(arcount*sizeof(struct dns_record*));
unsigned short idx = 0, _idx; /* This keeps track how far we have parsed the data */
int i;
for (i = 0; i < qdcount; i++) { /*{{{*/
ppkt->queries[i] = GNUNET_malloc(sizeof(struct dns_query));
unsigned char* name = alloca(255); /* see RFC1035, it can't be more than this. */
_idx = parse_dns_name(name, pkt->data, idx);
ppkt->queries[i]->namelen = _idx - idx;
idx = _idx;
ppkt->queries[i]->name = GNUNET_malloc(ppkt->queries[i]->namelen + 1);
memcpy(ppkt->queries[i]->name, name, ppkt->queries[i]->namelen + 1);
ppkt->queries[i]->qtype = *((unsigned short*)(pkt->data+idx));
idx += 2;
ppkt->queries[i]->qclass = *((unsigned short*)(pkt->data+idx));
idx += 2;
}
/*}}}*/
idx = parse_dns_record(pkt->data, ppkt->answers, ancount, idx);
idx = parse_dns_record(pkt->data, ppkt->nameservers, nscount, idx);
idx = parse_dns_record(pkt->data, ppkt->additional, arcount, idx);
return ppkt;
}
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