static void
rr_iter_find_nxt(priv_getdns_rr_iter *i)
{
assert(i);
assert(i->rr_type);
i->nxt = i->n < GLDNS_QDCOUNT(i->pkt)
? i->rr_type + 4
: i->rr_type + 10 > i->pkt_end
? i->pkt_end
: i->rr_type + 10 + gldns_read_uint16(i->rr_type + 8) > i->pkt_end
? i->pkt_end
: i->rr_type + 10 + gldns_read_uint16(i->rr_type + 8);
}
priv_getdns_rdf_iter *
priv_getdns_rdf_iter_init(priv_getdns_rdf_iter *i, priv_getdns_rr_iter *rr)
{
const priv_getdns_rr_def *rr_def;
assert(i);
assert(rr);
i->end = NULL;
/* rr_iter already done or in question section */
if (!rr->pos || rr->n < GLDNS_QDCOUNT(rr->pkt))
goto done;
i->pkt = rr->pkt;
i->pkt_end = rr->pkt_end;
rr_def = priv_getdns_rr_def_lookup(gldns_read_uint16(rr->rr_type));
i->rdd_pos = rr_def->rdata;
i->rdd_end = rr_def->rdata + rr_def->n_rdata_fields;
/* No space to read rdata len */
if (rr->rr_type + 10 >= rr->nxt)
goto done;
i->rdd_repeat = NULL;
i->pos = rr->rr_type + 10;
i->end = rr->nxt;
/* rdata */
if (i->rdd_pos != i->rdd_end)
return rdf_iter_find_nxt(i);
done:
i->pos = NULL;
return NULL;
}
static priv_getdns_rdf_iter *
rdf_iter_find_nxt(priv_getdns_rdf_iter *i)
{
uint8_t *pos;
assert(i);
assert(i->pos);
assert(i->rdd_pos);
if (!i->rdd_repeat && (i->rdd_pos->type & GETDNS_RDF_REPEAT)) {
i->rdd_repeat = i->rdd_pos;
if (i->rdd_pos->type == GETDNS_RDF_REPEAT &&
++i->rdd_pos == i->rdd_end)
goto done;
}
if (i->rdd_pos->type & GETDNS_RDF_FIXEDSZ)
i->nxt = i->pos + (i->rdd_pos->type & GETDNS_RDF_FIXEDSZ);
else if ((i->rdd_pos->type & GETDNS_RDF_LEN_VAL) == 0x100)
i->nxt = i->pos < i->end ? i->pos + *i->pos + 1 : i->end;
else if ((i->rdd_pos->type & GETDNS_RDF_LEN_VAL) == 0x200)
i->nxt = i->pos + 1 < i->end
? i->pos + gldns_read_uint16(i->pos) + 2 : i->end;
else if (i->rdd_pos->type & GETDNS_RDF_DNAME)
for (pos = i->pos; pos < i->end; pos += *pos + 1) {
if (!*pos) {
i->nxt = pos + 1;
break;
} else if ((*pos & 0xC0) == 0xC0) {
i->nxt = pos + 2;
break;
} else if (*pos & 0xC0) /* Uknown label type */
goto done;
}
else if ((i->rdd_pos->type & GETDNS_RDF_SPECIAL) && i->rdd_pos->special) {
if (!(i->nxt = i->rdd_pos->special->rdf_end(
i->pkt, i->pkt_end, i->pos)))
i->nxt = i->end;
} else /* RDF is for remaining data */
i->nxt = i->end;
if ( i->nxt <= i->end &&
/* Empty rdata fields are only allowed in case of non-repeating
* remaining data. So only the GETDNS_RDF_BINDATA bit is set.
*/
(i->nxt > i->pos || (i->rdd_pos->type == GETDNS_RDF_BINDATA)))
return i;
done:
i->pos = NULL;
return NULL;
}
static priv_getdns_rdf_iter *
rdf_iter_find_nxt(priv_getdns_rdf_iter *i)
{
uint8_t *pos;
assert(i);
assert(i->pos);
assert(i->rdd_pos);
if (!i->rdd_repeat && (i->rdd_pos->type & GETDNS_RDF_REPEAT)) {
i->rdd_repeat = i->rdd_pos;
if (i->rdd_pos->type == GETDNS_RDF_REPEAT &&
++i->rdd_pos == i->rdd_end)
goto done;
}
if (i->rdd_pos->type & GETDNS_RDF_FIXEDSZ)
i->nxt = i->pos + (i->rdd_pos->type & GETDNS_RDF_FIXEDSZ);
else if ((i->rdd_pos->type & GETDNS_RDF_LEN_VAL) == 0x100)
i->nxt = i->pos < i->end ? i->pos + *i->pos + 1 : i->end;
else if ((i->rdd_pos->type & GETDNS_RDF_LEN_VAL) == 0x200)
i->nxt = i->pos + 1 < i->end
? i->pos + gldns_read_uint16(i->pos) + 2 : i->end;
else if ((i->rdd_pos->type & GETDNS_RDF_DNAME) == GETDNS_RDF_DNAME)
for (pos = i->pos; pos < i->end; pos += *pos + 1) {
if (!*pos) {
i->nxt = pos + 1;
break;
} else if ((*pos & 0xC0) == 0xC0) {
i->nxt = pos + 2;
break;
} else if (*pos & 0xC0) /* Uknown label type */
goto done;
}
else if ((i->rdd_pos->type & GETDNS_RDF_SPECIAL) && i->rdd_pos->special) {
if (!(i->nxt = i->rdd_pos->special->rdf_end(
i->pkt, i->pkt_end, i->pos)))
i->nxt = i->end;
} else
i->nxt = i->end;
if (i->nxt <= i->end)
return i;
done:
i->pos = NULL;
return NULL;
}
static uint8_t *
dname_if_or_as_decompressed(uint8_t *pkt, uint8_t *pkt_end, uint8_t *pos,
uint8_t *buf, size_t *len, size_t refs)
{
uint16_t offset;
uint8_t *start, *dst;
assert(pkt);
assert(pkt_end);
assert(pos);
assert(buf);
assert(len);
if (refs > GLDNS_MAX_POINTERS)
goto error;
if ((*pos & 0xC0) == 0xC0) {
if (pos + 1 >= pkt_end)
goto error;
offset = gldns_read_uint16(pos) & 0x3FFF;
if (pkt + offset >= pkt_end)
goto error;
return dname_if_or_as_decompressed(pkt, pkt_end, pkt + offset,
buf, len, refs + 1);
}
if (*pos & 0xC0)
goto error;
start = pos;
*len = 0;
while (*pos) {
if ((*pos & 0xC0) == 0xC0)
break;
else if (*pos & 0xC0)
goto error;
*len += *pos + 1;
pos += *pos + 1;
}
if (!*pos) {
*len += 1;
return start;
}
dst = buf;
for (;;) {
if (pos > start) {
if (dst + (pos - start) > buf + 255)
goto error;
(void) memcpy(dst, start, pos - start);
dst += (pos - start);
start = pos;
}
if ((*pos & 0xC0) == 0xC0) {
if (pos + 1 >= pkt_end)
goto error;
offset = gldns_read_uint16(pos) & 0x3FFF;
if (pkt + offset >= pkt_end)
goto error;
start = pos = pkt + offset;
if (++refs > 256)
goto error;
}
if ((*pos & 0xC0) == 0xC0)
continue;
else if (*pos & 0xC0)
goto error;
else if (!*pos) {
*len += 1;
*dst = 0;
return buf;
}
*len += *pos + 1;
pos += *pos + 1;
}
error:
*len = 0;
return NULL;
}
