/* parse the received packet. returns xfrd packet result code. */
static enum xfrd_packet_result
xfrd_parse_received_xfr_packet(xfrd_zone_t* zone, buffer_type* packet,
xfrd_soa_t* soa)
{
size_t rr_count;
size_t qdcount = QDCOUNT(packet);
size_t ancount = ANCOUNT(packet), ancount_todo;
int done = 0;
/* has to be axfr / ixfr reply */
if(!buffer_available(packet, QHEADERSZ)) {
log_msg(LOG_INFO, "packet too small");
return xfrd_packet_bad;
}
/* only check ID in first response message. Could also check that
* AA bit and QR bit are set, but not needed.
*/
DEBUG(DEBUG_XFRD,2, (LOG_INFO,
"got query with ID %d and %d needed", ID(packet), zone->query_id));
if(ID(packet) != zone->query_id) {
log_msg(LOG_ERR, "xfrd: zone %s received bad query id from %s, "
"dropped",
zone->apex_str, zone->master->ip_address_spec);
return xfrd_packet_bad;
}
/* check RCODE in all response messages */
if(RCODE(packet) != RCODE_OK) {
log_msg(LOG_ERR, "xfrd: zone %s received error code %s from "
"%s",
zone->apex_str, rcode2str(RCODE(packet)),
zone->master->ip_address_spec);
if (RCODE(packet) == RCODE_IMPL ||
RCODE(packet) == RCODE_FORMAT) {
return xfrd_packet_notimpl;
}
return xfrd_packet_bad;
}
/* check TSIG */
if(zone->master->key_options) {
if(!xfrd_xfr_process_tsig(zone, packet)) {
DEBUG(DEBUG_XFRD,1, (LOG_ERR, "dropping xfr reply due "
"to bad TSIG"));
return xfrd_packet_bad;
}
}
buffer_skip(packet, QHEADERSZ);
/* skip question section */
for(rr_count = 0; rr_count < qdcount; ++rr_count) {
if (!packet_skip_rr(packet, 1)) {
log_msg(LOG_ERR, "xfrd: zone %s, from %s: bad RR in "
"question section",
zone->apex_str, zone->master->ip_address_spec);
return xfrd_packet_bad;
}
}
if(zone->msg_rr_count == 0 && ancount == 0) {
if(zone->tcp_conn == -1 && TC(packet)) {
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "xfrd: TC flagged"));
return xfrd_packet_tcp;
}
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "xfrd: too short xfr packet: no "
"answer"));
return xfrd_packet_bad;
}
ancount_todo = ancount;
if(zone->msg_rr_count == 0) {
/* parse the first RR, see if it is a SOA */
if(!packet_skip_dname(packet) ||
!xfrd_parse_soa_info(packet, soa))
{
DEBUG(DEBUG_XFRD,1, (LOG_ERR, "xfrd: zone %s, from %s: "
"no SOA begins answer"
" section",
zone->apex_str, zone->master->ip_address_spec));
return xfrd_packet_bad;
}
if(zone->soa_disk_acquired != 0 &&
zone->state != xfrd_zone_expired /* if expired - accept anything */ &&
compare_serial(ntohl(soa->serial), ntohl(zone->soa_disk.serial)) < 0) {
DEBUG(DEBUG_XFRD,1, (LOG_INFO,
"xfrd: zone %s ignoring old serial from %s",
zone->apex_str, zone->master->ip_address_spec));
VERBOSITY(1, (LOG_INFO,
"xfrd: zone %s ignoring old serial from %s",
zone->apex_str, zone->master->ip_address_spec));
return xfrd_packet_bad;
}
if(zone->soa_disk_acquired != 0 && zone->soa_disk.serial == soa->serial) {
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "xfrd: zone %s got "
"update indicating "
"current serial",
zone->apex_str));
/* (even if notified) the lease on the current soa is renewed */
zone->soa_disk_acquired = xfrd_time();
if(zone->soa_nsd.serial == soa->serial)
zone->soa_nsd_acquired = xfrd_time();
xfrd_set_zone_state(zone, xfrd_zone_ok);
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "xfrd: zone %s is ok",
zone->apex_str));
if(zone->soa_notified_acquired == 0) {
/* not notified or anything, so stop asking around */
zone->round_num = -1; /* next try start a new round */
xfrd_set_timer_refresh(zone);
return xfrd_packet_newlease;
}
/* try next master */
return xfrd_packet_bad;
}
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "IXFR reply has ok serial (have \
%u, reply %u).", ntohl(zone->soa_disk.serial), ntohl(soa->serial)));
/* serial is newer than soa_disk */
if(ancount == 1) {
/* single record means it is like a notify */
(void)xfrd_handle_incoming_notify(zone, soa);
}
else if(zone->soa_notified_acquired && zone->soa_notified.serial &&
compare_serial(ntohl(zone->soa_notified.serial), ntohl(soa->serial)) < 0) {
/* this AXFR/IXFR notifies me that an even newer serial exists */
zone->soa_notified.serial = soa->serial;
}
zone->msg_new_serial = ntohl(soa->serial);
zone->msg_rr_count = 1;
zone->msg_is_ixfr = 0;
if(zone->soa_disk_acquired)
zone->msg_old_serial = ntohl(zone->soa_disk.serial);
else zone->msg_old_serial = 0;
ancount_todo = ancount - 1;
}
if(zone->tcp_conn == -1 && TC(packet)) {
DEBUG(DEBUG_XFRD,1, (LOG_INFO,
"xfrd: zone %s received TC from %s. retry tcp.",
zone->apex_str, zone->master->ip_address_spec));
return xfrd_packet_tcp;
}
if(zone->tcp_conn == -1 && ancount < 2) {
/* too short to be a real ixfr/axfr data transfer: need at */
/* least two RRs in the answer section. */
/* The serial is newer, so try tcp to this master. */
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "xfrd: udp reply is short. Try "
"tcp anyway."));
return xfrd_packet_tcp;
}
if(!xfrd_xfr_check_rrs(zone, packet, ancount_todo, &done, soa))
{
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "xfrd: zone %s sent bad xfr "
"reply.", zone->apex_str));
return xfrd_packet_bad;
}
if(zone->tcp_conn == -1 && done == 0) {
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "xfrd: udp reply incomplete"));
return xfrd_packet_bad;
}
if(done == 0)
return xfrd_packet_more;
if(zone->master->key_options) {
if(zone->tsig.updates_since_last_prepare != 0) {
log_msg(LOG_INFO, "xfrd: last packet of reply has no "
"TSIG");
return xfrd_packet_bad;
}
}
return xfrd_packet_transfer;
}
/* return value 0: syntaxerror,badIXFR, 1:OK, 2:done_and_skip_it */
static int
apply_ixfr(namedb_type* db, FILE *in, const off_t* startpos,
const char* zone, uint32_t serialno, nsd_options_t* opt,
uint16_t id, uint32_t seq_nr, uint32_t seq_total,
int* is_axfr, int* delete_mode, int* rr_count,
size_t child_count)
{
uint32_t filelen, msglen, pkttype, timestamp[2];
int qcount, ancount, counter;
buffer_type* packet;
region_type* region;
int i;
uint16_t rrlen;
const dname_type *dname_zone, *dname;
zone_type* zone_db;
domain_type* last_in_list;
char file_zone_name[3072];
uint32_t file_serial, file_seq_nr;
uint16_t file_id;
off_t mempos;
memmove(&mempos, startpos, sizeof(off_t));
if(fseeko(in, mempos, SEEK_SET) == -1) {
log_msg(LOG_INFO, "could not fseeko: %s.", strerror(errno));
return 0;
}
/* read ixfr packet RRs and apply to in memory db */
if(!diff_read_32(in, &pkttype) || pkttype != DIFF_PART_IXFR) {
log_msg(LOG_ERR, "could not read type or wrong type");
return 0;
}
if(!diff_read_32(in, ×tamp[0]) ||
!diff_read_32(in, ×tamp[1])) {
log_msg(LOG_ERR, "could not read timestamp");
return 0;
}
if(!diff_read_32(in, &filelen)) {
log_msg(LOG_ERR, "could not read len");
return 0;
}
/* read header */
if(filelen < QHEADERSZ + sizeof(uint32_t)*3 + sizeof(uint16_t)) {
log_msg(LOG_ERR, "msg too short");
return 0;
}
region = region_create(xalloc, free);
if(!region) {
log_msg(LOG_ERR, "out of memory");
return 0;
}
if(!diff_read_str(in, file_zone_name, sizeof(file_zone_name)) ||
!diff_read_32(in, &file_serial) ||
!diff_read_16(in, &file_id) ||
!diff_read_32(in, &file_seq_nr))
{
log_msg(LOG_ERR, "could not part data");
region_destroy(region);
return 0;
}
if(strcmp(file_zone_name, zone) != 0 || serialno != file_serial ||
id != file_id || seq_nr != file_seq_nr) {
log_msg(LOG_ERR, "internal error: reading part with changed id");
region_destroy(region);
return 0;
}
msglen = filelen - sizeof(uint32_t)*3 - sizeof(uint16_t)
- strlen(file_zone_name);
packet = buffer_create(region, QIOBUFSZ);
dname_zone = dname_parse(region, zone);
zone_db = find_zone(db, dname_zone, opt, child_count);
if(!zone_db) {
log_msg(LOG_ERR, "no zone exists");
region_destroy(region);
/* break out and stop the IXFR, ignore it */
return 2;
}
if(msglen > QIOBUFSZ) {
log_msg(LOG_ERR, "msg too long");
region_destroy(region);
return 0;
}
buffer_clear(packet);
if(fread(buffer_begin(packet), msglen, 1, in) != 1) {
log_msg(LOG_ERR, "short fread: %s", strerror(errno));
region_destroy(region);
return 0;
}
buffer_set_limit(packet, msglen);
/* only answer section is really used, question, additional and
authority section RRs are skipped */
qcount = QDCOUNT(packet);
ancount = ANCOUNT(packet);
buffer_skip(packet, QHEADERSZ);
/* skip queries */
for(i=0; i<qcount; ++i)
if(!packet_skip_rr(packet, 1)) {
log_msg(LOG_ERR, "bad RR in question section");
region_destroy(region);
return 0;
}
DEBUG(DEBUG_XFRD,2, (LOG_INFO, "diff: started packet for zone %s",
dname_to_string(dname_zone, 0)));
/* first RR: check if SOA and correct zone & serialno */
if(*rr_count == 0) {
DEBUG(DEBUG_XFRD,2, (LOG_INFO, "diff: %s parse first RR",
dname_to_string(dname_zone, 0)));
dname = dname_make_from_packet(region, packet, 1, 1);
if(!dname) {
log_msg(LOG_ERR, "could not parse dname");
region_destroy(region);
return 0;
}
if(dname_compare(dname_zone, dname) != 0) {
log_msg(LOG_ERR, "SOA dname %s not equal to zone",
dname_to_string(dname,0));
log_msg(LOG_ERR, "zone dname is %s",
dname_to_string(dname_zone,0));
region_destroy(region);
return 0;
}
if(!buffer_available(packet, 10)) {
log_msg(LOG_ERR, "bad SOA RR");
region_destroy(region);
return 0;
}
if(buffer_read_u16(packet) != TYPE_SOA ||
buffer_read_u16(packet) != CLASS_IN) {
log_msg(LOG_ERR, "first RR not SOA IN");
region_destroy(region);
return 0;
}
buffer_skip(packet, sizeof(uint32_t)); /* ttl */
if(!buffer_available(packet, buffer_read_u16(packet)) ||
!packet_skip_dname(packet) /* skip prim_ns */ ||
!packet_skip_dname(packet) /* skip email */) {
log_msg(LOG_ERR, "bad SOA RR");
region_destroy(region);
return 0;
}
if(buffer_read_u32(packet) != serialno) {
buffer_skip(packet, -4);
log_msg(LOG_ERR, "SOA serial %d different from commit %d",
buffer_read_u32(packet), serialno);
region_destroy(region);
return 0;
}
buffer_skip(packet, sizeof(uint32_t)*4);
counter = 1;
*rr_count = 1;
*is_axfr = 0;
*delete_mode = 0;
DEBUG(DEBUG_XFRD,2, (LOG_INFO, "diff: %s start count %d, ax %d, delmode %d",
dname_to_string(dname_zone, 0), *rr_count, *is_axfr, *delete_mode));
}
else counter = 0;
last_in_list = zone_db->apex;
for(; counter < ancount; ++counter,++(*rr_count))
{
uint16_t type, klass;
uint32_t ttl;
if(!(dname=dname_make_from_packet(region, packet, 1,1))) {
log_msg(LOG_ERR, "bad xfr RR dname %d", *rr_count);
region_destroy(region);
return 0;
}
if(!buffer_available(packet, 10)) {
log_msg(LOG_ERR, "bad xfr RR format %d", *rr_count);
region_destroy(region);
return 0;
}
type = buffer_read_u16(packet);
klass = buffer_read_u16(packet);
ttl = buffer_read_u32(packet);
rrlen = buffer_read_u16(packet);
if(!buffer_available(packet, rrlen)) {
log_msg(LOG_ERR, "bad xfr RR rdata %d, len %d have %d",
*rr_count, rrlen, (int)buffer_remaining(packet));
region_destroy(region);
return 0;
}
DEBUG(DEBUG_XFRD,2, (LOG_INFO, "diff: %s parsed count %d, ax %d, delmode %d",
dname_to_string(dname_zone, 0), *rr_count, *is_axfr, *delete_mode));
if(*rr_count == 1 && type != TYPE_SOA) {
/* second RR: if not SOA: this is an AXFR; delete all zone contents */
delete_zone_rrs(db, zone_db);
/* add everything else (incl end SOA) */
*delete_mode = 0;
*is_axfr = 1;
DEBUG(DEBUG_XFRD,2, (LOG_INFO, "diff: %s sawAXFR count %d, ax %d, delmode %d",
dname_to_string(dname_zone, 0), *rr_count, *is_axfr, *delete_mode));
}
if(*rr_count == 1 && type == TYPE_SOA) {
/* if the serial no of the SOA equals the serialno, then AXFR */
size_t bufpos = buffer_position(packet);
uint32_t thisserial;
if(!packet_skip_dname(packet) ||
!packet_skip_dname(packet) ||
buffer_remaining(packet) < sizeof(uint32_t)*5)
{
log_msg(LOG_ERR, "bad xfr SOA RR formerr.");
region_destroy(region);
return 0;
}
thisserial = buffer_read_u32(packet);
if(thisserial == serialno) {
/* AXFR */
delete_zone_rrs(db, zone_db);
*delete_mode = 0;
*is_axfr = 1;
}
/* must have stuff in memory for a successful IXFR,
* the serial number of the SOA has been checked
* previously (by check_for_bad_serial) if it exists */
if(!*is_axfr && !domain_find_rrset(zone_db->apex,
zone_db, TYPE_SOA)) {
log_msg(LOG_ERR, "%s SOA serial %d is not "
"in memory, skip IXFR", zone, serialno);
region_destroy(region);
/* break out and stop the IXFR, ignore it */
return 2;
}
buffer_set_position(packet, bufpos);
}
if(type == TYPE_SOA && !*is_axfr) {
/* switch from delete-part to add-part and back again,
just before soa - so it gets deleted and added too */
/* this means we switch to delete mode for the final SOA */
*delete_mode = !*delete_mode;
DEBUG(DEBUG_XFRD,2, (LOG_INFO, "diff: %s IXFRswapdel count %d, ax %d, delmode %d",
dname_to_string(dname_zone, 0), *rr_count, *is_axfr, *delete_mode));
}
if(type == TYPE_TSIG || type == TYPE_OPT) {
/* ignore pseudo RRs */
buffer_skip(packet, rrlen);
continue;
}
DEBUG(DEBUG_XFRD,2, (LOG_INFO, "xfr %s RR dname is %s type %s",
*delete_mode?"del":"add",
dname_to_string(dname,0), rrtype_to_string(type)));
if(*delete_mode) {
/* delete this rr */
if(!*is_axfr && type == TYPE_SOA && counter==ancount-1
&& seq_nr == seq_total-1) {
continue; /* do not delete final SOA RR for IXFR */
}
if(!delete_RR(db, dname, type, klass, last_in_list, packet,
rrlen, zone_db, region, *is_axfr)) {
region_destroy(region);
return 0;
}
if (!*is_axfr && last_in_list->nextdiff) {
last_in_list = last_in_list->nextdiff;
}
}
else
{
/* add this rr */
if(!add_RR(db, dname, type, klass, ttl, packet,
rrlen, zone_db, *is_axfr)) {
region_destroy(region);
return 0;
}
}
}
fix_empty_terminals(zone_db);
region_destroy(region);
return 1;
}