/** store msg section in wireformat buffer, return RETVAL_* */
static int
insert_section(struct reply_info* rep, size_t num_rrsets, uint16_t* num_rrs,
ldns_buffer* pkt, size_t rrsets_before, uint32_t timenow,
struct regional* region, struct compress_tree_node** tree,
ldns_pkt_section s, uint16_t qtype, int dnssec, size_t rr_offset)
{
int r;
size_t i, setstart;
*num_rrs = 0;
if(s != LDNS_SECTION_ADDITIONAL) {
if(s == LDNS_SECTION_ANSWER && qtype == LDNS_RR_TYPE_ANY)
dnssec = 1; /* include all types in ANY answer */
for(i=0; i<num_rrsets; i++) {
setstart = ldns_buffer_position(pkt);
if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i],
pkt, num_rrs, timenow, region, 1, 1, tree,
s, qtype, dnssec, rr_offset))
!= RETVAL_OK) {
/* Bad, but if due to size must set TC bit */
/* trim off the rrset neatly. */
ldns_buffer_set_position(pkt, setstart);
return r;
}
}
} else {
for(i=0; i<num_rrsets; i++) {
setstart = ldns_buffer_position(pkt);
if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i],
pkt, num_rrs, timenow, region, 1, 0, tree,
s, qtype, dnssec, rr_offset))
!= RETVAL_OK) {
ldns_buffer_set_position(pkt, setstart);
return r;
}
}
if(dnssec)
for(i=0; i<num_rrsets; i++) {
setstart = ldns_buffer_position(pkt);
if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i],
pkt, num_rrs, timenow, region, 0, 1, tree,
s, qtype, dnssec, rr_offset))
!= RETVAL_OK) {
ldns_buffer_set_position(pkt, setstart);
return r;
}
}
}
return RETVAL_OK;
}
size_t
pkt_dname_len(ldns_buffer* pkt)
{
size_t len = 0;
int ptrcount = 0;
uint8_t labellen;
size_t endpos = 0;
/* read dname and determine length */
/* check compression pointers, loops, out of bounds */
while(1) {
/* read next label */
if(ldns_buffer_remaining(pkt) < 1)
return 0;
labellen = ldns_buffer_read_u8(pkt);
if(LABEL_IS_PTR(labellen)) {
/* compression ptr */
uint16_t ptr;
if(ldns_buffer_remaining(pkt) < 1)
return 0;
ptr = PTR_OFFSET(labellen, ldns_buffer_read_u8(pkt));
if(ptrcount++ > MAX_COMPRESS_PTRS)
return 0; /* loop! */
if(ldns_buffer_limit(pkt) <= ptr)
return 0; /* out of bounds! */
if(!endpos)
endpos = ldns_buffer_position(pkt);
ldns_buffer_set_position(pkt, ptr);
} else {
/* label contents */
if(labellen > 0x3f)
return 0; /* label too long */
len += 1 + labellen;
if(len > LDNS_MAX_DOMAINLEN)
return 0;
if(labellen == 0) {
/* end of dname */
break;
}
if(ldns_buffer_remaining(pkt) < labellen)
return 0;
ldns_buffer_skip(pkt, (ssize_t)labellen);
}
}
if(endpos)
ldns_buffer_set_position(pkt, endpos);
return len;
}
int reply_info_parse(ldns_buffer* pkt, struct alloc_cache* alloc,
struct query_info* qinf, struct reply_info** rep,
struct regional* region, struct edns_data* edns)
{
/* use scratch pad region-allocator during parsing. */
struct msg_parse* msg;
int ret;
qinf->qname = NULL;
*rep = NULL;
if(!(msg = regional_alloc(region, sizeof(*msg)))) {
return LDNS_RCODE_SERVFAIL;
}
memset(msg, 0, sizeof(*msg));
ldns_buffer_set_position(pkt, 0);
if((ret = parse_packet(pkt, msg, region)) != 0) {
return ret;
}
if((ret = parse_extract_edns(msg, edns)) != 0)
return ret;
/* parse OK, allocate return structures */
/* this also performs dname decompression */
if(!parse_create_msg(pkt, msg, alloc, qinf, rep, NULL)) {
query_info_clear(qinf);
reply_info_parsedelete(*rep, alloc);
*rep = NULL;
return LDNS_RCODE_SERVFAIL;
}
return 0;
}
int
ldns_bgetc(ldns_buffer *buffer)
{
if (!ldns_buffer_available_at(buffer, buffer->_position, sizeof(uint8_t))) {
ldns_buffer_set_position(buffer, ldns_buffer_limit(buffer));
/* ldns_buffer_rewind(buffer);*/
return EOF;
}
return (int)ldns_buffer_read_u8(buffer);
}
/* Create response according to the ldns packet content */
int createResponse(struct module_qstate* qstate, ldns_buffer* pkt)
{
struct msg_parse* prs;
struct edns_data edns;
/* parse message */
prs = (struct msg_parse*) regional_alloc(qstate->env->scratch, sizeof(struct msg_parse));
if (!prs) {
log_err("storeResponse: out of memory on incoming message");
return 0;
}
memset(prs, 0, sizeof(*prs));
memset(&edns, 0, sizeof(edns));
ldns_buffer_set_position(pkt, 0);
if (parse_packet(pkt, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) {
verbose(VERB_ALGO, "storeResponse: parse error on reply packet");
return 0;
}
/* edns is not examined, but removed from message to help cache */
if(parse_extract_edns(prs, &edns) != LDNS_RCODE_NOERROR)
return 0;
/* remove CD-bit, we asked for in case we handle validation ourself */
prs->flags &= ~BIT_CD;
/* allocate response dns_msg in region */
qstate->return_msg = (struct dns_msg*)regional_alloc(qstate->region, sizeof(struct dns_msg));
if (!qstate->return_msg)
return 0;
memset(qstate->return_msg, 0, sizeof(*qstate->return_msg));
if(!parse_create_msg(pkt, prs, NULL, &(qstate->return_msg)->qinfo, &(qstate->return_msg)->rep, qstate->region)) {
log_err("storeResponse: malloc failure: allocating incoming dns_msg");
return 0;
}
/* Make sure that the RA flag is set (since the presence of
* this module means that recursion is available) */
/* qstate->return_msg->rep->flags |= BIT_RA; */
/* Clear the AA flag */
/* FIXME: does this action go here or in some other module? */
/*qstate->return_msg->rep->flags &= ~BIT_AA; */
/* make sure QR flag is on */
/*qstate->return_msg->rep->flags |= BIT_QR; */
if(verbosity >= VERB_ALGO)
log_dns_msg("storeResponse: packet:", &qstate->return_msg->qinfo, qstate->return_msg->rep);
return 1;
}
/** get additional name from rrset RR, return false if no name present */
static int
get_additional_name(struct rrset_parse* rrset, struct rr_parse* rr,
uint8_t** nm, size_t* nmlen, ldns_buffer* pkt)
{
size_t offset = 0;
size_t len, oldpos;
switch(rrset->type) {
case LDNS_RR_TYPE_MB:
case LDNS_RR_TYPE_MD:
case LDNS_RR_TYPE_MF:
case LDNS_RR_TYPE_NS:
offset = 0;
break;
case LDNS_RR_TYPE_MX:
case LDNS_RR_TYPE_KX:
offset = 2;
break;
case LDNS_RR_TYPE_SRV:
offset = 6;
break;
case LDNS_RR_TYPE_NAPTR:
/* TODO: NAPTR not supported, glue stripped off */
return 0;
default:
return 0;
}
len = ldns_read_uint16(rr->ttl_data+sizeof(uint32_t));
if(len < offset+1)
return 0; /* rdata field too small */
*nm = rr->ttl_data+sizeof(uint32_t)+sizeof(uint16_t)+offset;
oldpos = ldns_buffer_position(pkt);
ldns_buffer_set_position(pkt, (size_t)(*nm - ldns_buffer_begin(pkt)));
*nmlen = pkt_dname_len(pkt);
ldns_buffer_set_position(pkt, oldpos);
if(*nmlen == 0)
return 0;
return 1;
}
/** get msg reply struct (in temp region) */
static struct reply_info*
parse_reply(ldns_buffer* pkt, struct regional* region, struct query_info* qi)
{
struct reply_info* rep;
struct msg_parse* msg;
if(!(msg = regional_alloc(region, sizeof(*msg)))) {
return NULL;
}
memset(msg, 0, sizeof(*msg));
ldns_buffer_set_position(pkt, 0);
if(parse_packet(pkt, msg, region) != 0)
return 0;
if(!parse_create_msg(pkt, msg, NULL, qi, &rep, region)) {
return 0;
}
return rep;
}
ldns_buffer *
read_hex_buffer(char *filename)
{
uint8_t *wire;
size_t wiresize;
ldns_buffer *result_buffer = NULL;
wire = xmalloc(LDNS_MAX_PACKETLEN);
wiresize = packetbuffromfile(filename, wire);
result_buffer = LDNS_MALLOC(ldns_buffer);
ldns_buffer_new_frm_data(result_buffer, wire, wiresize);
ldns_buffer_set_position(result_buffer, ldns_buffer_capacity(result_buffer));
xfree(wire);
return result_buffer;
}
void
attach_edns_record(ldns_buffer* pkt, struct edns_data* edns)
{
size_t len;
if(!edns || !edns->edns_present)
return;
/* inc additional count */
ldns_buffer_write_u16_at(pkt, 10,
ldns_buffer_read_u16_at(pkt, 10) + 1);
len = ldns_buffer_limit(pkt);
ldns_buffer_clear(pkt);
ldns_buffer_set_position(pkt, len);
/* write EDNS record */
ldns_buffer_write_u8(pkt, 0); /* '.' label */
ldns_buffer_write_u16(pkt, LDNS_RR_TYPE_OPT); /* type */
ldns_buffer_write_u16(pkt, edns->udp_size); /* class */
ldns_buffer_write_u8(pkt, edns->ext_rcode); /* ttl */
ldns_buffer_write_u8(pkt, edns->edns_version);
ldns_buffer_write_u16(pkt, edns->bits);
ldns_buffer_write_u16(pkt, 0); /* rdatalen */
ldns_buffer_flip(pkt);
}
/** do the rdata copy */
static int
rdata_copy(ldns_buffer* pkt, struct packed_rrset_data* data, uint8_t* to,
struct rr_parse* rr, uint32_t* rr_ttl, uint16_t type)
{
uint16_t pkt_len;
const ldns_rr_descriptor* desc;
*rr_ttl = ldns_read_uint32(rr->ttl_data);
/* RFC 2181 Section 8. if msb of ttl is set treat as if zero. */
if(*rr_ttl & 0x80000000U)
*rr_ttl = 0;
if(*rr_ttl < MIN_TTL)
*rr_ttl = MIN_TTL;
if(*rr_ttl < data->ttl)
data->ttl = *rr_ttl;
if(rr->outside_packet) {
/* uncompressed already, only needs copy */
memmove(to, rr->ttl_data+sizeof(uint32_t), rr->size);
return 1;
}
ldns_buffer_set_position(pkt, (size_t)
(rr->ttl_data - ldns_buffer_begin(pkt) + sizeof(uint32_t)));
/* insert decompressed size into rdata len stored in memory */
/* -2 because rdatalen bytes are not included. */
pkt_len = htons(rr->size - 2);
memmove(to, &pkt_len, sizeof(uint16_t));
to += 2;
/* read packet rdata len */
pkt_len = ldns_buffer_read_u16(pkt);
if(ldns_buffer_remaining(pkt) < pkt_len)
return 0;
desc = ldns_rr_descript(type);
if(pkt_len > 0 && desc && desc->_dname_count > 0) {
int count = (int)desc->_dname_count;
int rdf = 0;
size_t len;
size_t oldpos;
/* decompress dnames. */
while(pkt_len > 0 && count) {
switch(desc->_wireformat[rdf]) {
case LDNS_RDF_TYPE_DNAME:
oldpos = ldns_buffer_position(pkt);
dname_pkt_copy(pkt, to,
ldns_buffer_current(pkt));
to += pkt_dname_len(pkt);
pkt_len -= ldns_buffer_position(pkt)-oldpos;
count--;
len = 0;
break;
case LDNS_RDF_TYPE_STR:
len = ldns_buffer_current(pkt)[0] + 1;
break;
default:
len = get_rdf_size(desc->_wireformat[rdf]);
break;
}
if(len) {
memmove(to, ldns_buffer_current(pkt), len);
to += len;
ldns_buffer_skip(pkt, (ssize_t)len);
log_assert(len <= pkt_len);
pkt_len -= len;
}
rdf++;
}
}
/* copy remaining rdata */
if(pkt_len > 0)
memmove(to, ldns_buffer_current(pkt), pkt_len);
return 1;
}
