int
d_a_p(dns_pkt_a * dpa, char *buf, int limitlen)
{
int offset, rdlen;
uint16_t u;
int i;
if ((rdlen = nametolbl(dpa->name, buf)) == -1)
return -1;
offset = rdlen;
if (offset + 10 > limitlen)
err_intret(ERR_DNSPLB);
buf += offset;
u = htons(dpa->type);
memcpy(buf, &u, 2);
buf += 2;
offset += 2;
u = htons(dpa->cl);
memcpy(buf, &u, 2);
buf += 2;
offset += 2;
i = htonl(dpa->ttl);
memcpy(buf, &i, 4);
buf += 4;
offset += 4;
if (dpa->type == T_A) {
if (offset + dpa->rdlength > limitlen)
err_intret(ERR_DNSPLB);
memcpy(buf + 2, dpa->rdata, dpa->rdlength);
offset += dpa->rdlength;
} else if (dpa->type == T_MX) {
memcpy(buf + 2, dpa->rdata, 2);
if ((rdlen = nametolbl(dpa->rdata + 2, buf + 4)) == -1) {
error(err_str);
err_ret(ERR_DNSMDA, -1);
}
offset += rdlen + 2;
if (offset > limitlen)
err_ret(ERR_DNSPLB, -1);
dpa->rdlength = rdlen + 2;
} else {
if ((rdlen = nametolbl(dpa->rdata, buf + 2)) == -1) {
error(err_str);
err_ret(ERR_DNSMDA, -1);
}
offset += rdlen;
if (offset > limitlen)
err_ret(ERR_DNSPLB, -1);
dpa->rdlength = rdlen;
}
u = htons(dpa->rdlength);
memcpy(buf, &u, 2);
offset += 2;
return offset;
}
/*
* This is a main function: takes the pkt-buf and translate
* it in structured data.
* It cares about dns_pkt allocations.
*
* Returns:
* -1 on E_INTRPRT
* 0 if pkt must be discarded.
* Number of bytes read otherwise
*/
int
d_u(char *buf, int pktlen, dns_pkt ** dpp)
{
dns_pkt *dp;
int offset = 0, res;
char *crow;
crow = buf;
/* Controls pkt consistency: we must at least read pkt headers */
if (pktlen < DNS_HDR_SZ)
err_ret(ERR_DNSMDP, 0);
*dpp = dp = create_dns_pkt();
/* Writes headers */
offset += d_hdr_u(buf, &(dp->pkt_hdr));
if (pktlen > DNS_MAX_SZ) /* If pkt is too long: the headers are written,
* so we can reply with E_INTRPRT
*/
err_intret(ERR_DNSPLB);
crow += offset;
/* Writes qsts */
if (dp->pkt_hdr.qdcount) {
if ((res = d_qsts_u(buf, crow, dp, pktlen - offset)) == -1) {
error(err_str);
err_intret(ERR_DNSMDP);
}
offset += res;
crow += res;
}
if (dp->pkt_hdr.ancount) {
if ((res =
d_as_u(buf, crow, &(dp->pkt_answ), pktlen - offset,
DP_ANCOUNT(dp))) == -1) {
error(err_str);
err_intret(ERR_DNSMDP);
}
offset += res;
}
/*crow+=res;
if ((res=dpkttoas(buf,crow,&(dp->pkt_auth),pktlen-offset,DP_NSCOUNT(dp)))==-1)
return -1;
offset+=res;
crow+=res;
if ((res=dpkttoas(buf,crow,&(dp->pkt_add),pktlen-offset,DP_ARCOUNT(dp)))==-1)
return -1; */
return offset;
}
/*
* like d_qs_u. count is the number of section to read.
* -1 on error. Bytes readed otherwise.
*/
int d_as_u(char *start_buf,char *buf,dns_pkt_a **dpa,int limit_len,int count)
{
int offset=0,res;
int i;
if (!count) return 0;
for(i=0;i<count;i++) {
if ((res=d_a_u(start_buf,buf+offset,dpa,limit_len-offset))==-1) {
error(err_str);
err_intret(ERR_DNSMDD);
}
offset+=res;
}
return offset;
}
/*
* The behavior of this function is in all similar to dpkttoqst.
* Returns -1 on error. Bytes readed otherwise.
*/
int
d_a_u(char *start_buf, char *buf, dns_pkt_a ** dpa_orig, int limit_len)
{
int count, rdlen;
dns_pkt_a *dpa;
uint16_t s;
uint32_t ui;
dpa = dns_add_a(dpa_orig);
/* get name */
if ((count = lbltoname(buf, start_buf, dpa->name, limit_len)) == -1) {
error(err_str);
err_ret(ERR_DNSMDD, -1);
}
buf += count;
/* Now we have to write 2+2+4+2 bytes */
if (count + 10 > limit_len)
err_ret(ERR_DNSPLB, -1);
memcpy(&s, buf, 2);
dpa->type = ntohs(s);
count += 2;
buf += 2;
memcpy(&s, buf, 2);
dpa->cl = ntohs(s);
count += 2;
buf += 2;
memcpy(&ui, buf, 4);
dpa->ttl = ntohl(ui);
count += 4;
buf += 4;
memcpy(&s, buf, 2);
dpa->rdlength = ntohs(s);
count += 2;
buf += 2;
rdlen = dpa->rdlength;
if (rdlen > DNS_MAX_HNAME_LEN)
err_ret(ERR_DNSMDD, -1);
/* Now we have to write dpa->rdlength bytes */
if (count + rdlen > limit_len)
err_ret(ERR_DNSPLB, -1);
if (dpa->type == T_A) {
memcpy(dpa->rdata, buf, rdlen); /* 32bit address */
count += rdlen;
} else if (dpa->type == T_AAAA) {
memcpy(dpa->rdata, buf, rdlen); /* 128bit address */
count += rdlen;
} else if (dpa->type == T_MX) {
memcpy(dpa->rdata, buf, 2);
if ((ui =
lbltoname(buf + 2, start_buf, dpa->rdata + 2,
rdlen - 2)) == -1) {
error(err_str);
err_ret(ERR_DNSMDD, -1);
}
if (rdlen != ui + 2) {
debug(DBG_NORMAL,
"In d_a_u(): rdlen (%d) differs from readed bytes (%d).",
rdlen, ui + 2);
err_ret(ERR_DNSMDD, -1);
}
count += 2 + ui;
} else {
if ((ui = lbltoname(buf, start_buf, dpa->rdata, rdlen)) == -1) {
error(err_str);
err_intret(ERR_DNSMDD);
}
if (rdlen != ui) {
debug(DBG_NORMAL,
"In d_a_u(): rdlen (%d) differs from readed bytes (%d).",
rdlen, ui);
err_ret(ERR_DNSMDD, -1);
}
count += ui;
}
return count;
}