From 5c1a5e28797f9c2eab1300247c052451ccd3be3e Mon Sep 17 00:00:00 2001
From: Libor Peltan <libor.peltan@nic.cz>
Date: Tue, 31 Jan 2017 18:07:28 +0100
Subject: [PATCH] XFR: proper handling of single-SOA first response message
---
src/knot/events/handlers/refresh.c | 152 +++++++++++++++++++++--------
1 file changed, 112 insertions(+), 40 deletions(-)
diff --git a/src/knot/events/handlers/refresh.c b/src/knot/events/handlers/refresh.c
index 1167d79cf3..ba202f5bd1 100644
--- a/src/knot/events/handlers/refresh.c
+++ b/src/knot/events/handlers/refresh.c
@@ -86,6 +86,14 @@ enum state {
STATE_TRANSFER,
};
+enum xfr_type {
+ XFR_TYPE_ERROR = -1,
+ XFR_TYPE_UNDETERMINED = 0,
+ XFR_TYPE_UPTODATE,
+ XFR_TYPE_AXFR,
+ XFR_TYPE_IXFR,
+};
+
struct refresh_data {
// transfer configuration, initialize appropriately:
@@ -99,7 +107,8 @@ struct refresh_data {
// internal state, initialize with zeroes:
enum state state; //!< Event processing state.
- bool is_ixfr; //!< Transfer is IXFR not AXFR.
+ enum xfr_type xfr_type; //!< Transer type (mostly IXFR versus AXFR).
+ knot_rrset_t *initial_soa_copy; //!< Copy of the received initial SOA.
struct xfr_stats stats; //!< Transfer statistics.
size_t change_size; //!< Size of added and removed RRs.
@@ -156,7 +165,7 @@ static int xfr_validate(zone_contents_t *zone, struct refresh_data *data)
if (zone->size > data->max_zone_size) {
ns_log(LOG_WARNING, data->zone->name,
- data->is_ixfr ? LOG_OPERATION_IXFR : LOG_OPERATION_AXFR,
+ data->xfr_type == XFR_TYPE_IXFR ? LOG_OPERATION_IXFR : LOG_OPERATION_AXFR,
LOG_DIRECTION_IN, data->remote, "zone size exceeded");
return KNOT_EZONESIZE;
}
@@ -249,7 +258,7 @@ static int axfr_consume_rr(const knot_rrset_t *rr, struct refresh_data *data)
data->change_size += knot_rrset_size(rr);
if (data->change_size > data->max_zone_size) {
AXFRIN_LOG(LOG_WARNING, data->zone->name, data->remote,
- "zone size exceeded");
+ "zone size exceeded");
return KNOT_STATE_FAIL;
}
@@ -297,9 +306,19 @@ static int axfr_consume(knot_pkt_t *pkt, struct refresh_data *data)
data->change_size = 0;
}
+ int next;
+ // Process saved SOA if fallback from IXFR
+ if (data->initial_soa_copy != NULL) {
+ next = axfr_consume_rr(data->initial_soa_copy, data);
+ knot_rrset_free(&data->initial_soa_copy, data->mm);
+ if (next != KNOT_STATE_CONSUME) {
+ return next;
+ }
+ }
+
// Process answer packet
xfr_stats_add(&data->stats, pkt->size);
- int next = axfr_consume_packet(pkt, data);
+ next = axfr_consume_packet(pkt, data);
// Finalize
if (next == KNOT_STATE_DONE) {
@@ -537,14 +556,14 @@ static int ixfr_consume_rr(const knot_rrset_t *rr, struct refresh_data *data)
int ret = ixfr_step(rr, data);
if (ret != KNOT_EOK) {
IXFRIN_LOG(LOG_WARNING, data->zone->name, data->remote,
- "failed (%s)", knot_strerror(ret));
+ "failed (%s)", knot_strerror(ret));
return KNOT_STATE_FAIL;
}
data->change_size += knot_rrset_size(rr);
if (data->change_size / 2 > data->max_zone_size) {
IXFRIN_LOG(LOG_WARNING, data->zone->name, data->remote,
- "transfer size exceeded");
+ "transfer size exceeded");
return KNOT_STATE_FAIL;
}
@@ -574,30 +593,38 @@ static int ixfr_consume_packet(knot_pkt_t *pkt, struct refresh_data *data)
return ret;
}
-static bool ixfr_check_header(const knot_pktsection_t *answer)
+static enum xfr_type determine_xfr_type(const knot_pktsection_t *answer,
+ uint32_t zone_serial, const knot_rrset_t *initial_soa)
{
- return answer->count >= 1 &&
- knot_pkt_rr(answer, 0)->type == KNOT_RRTYPE_SOA;
-}
-
-static bool ixfr_is_axfr(const knot_pktsection_t *answer)
-{
- if (answer->count < 2) {
- return false;
+ if (answer->count < 1) {
+ return XFR_TYPE_ERROR;
}
const knot_rrset_t *rr_one = knot_pkt_rr(answer, 0);
+ if (initial_soa != NULL) {
+ if (rr_one->type == KNOT_RRTYPE_SOA) {
+ return knot_rrset_equal(initial_soa, rr_one, KNOT_RRSET_COMPARE_WHOLE) ?
+ XFR_TYPE_AXFR : XFR_TYPE_IXFR;
+ }
+ return XFR_TYPE_AXFR;
+ }
+
+ if (answer->count == 1) {
+ if (rr_one->type == KNOT_RRTYPE_SOA) {
+ return serial_is_current(zone_serial, knot_soa_serial(&rr_one->rrs)) ?
+ XFR_TYPE_UPTODATE : XFR_TYPE_UNDETERMINED;
+ }
+ return XFR_TYPE_ERROR;
+ }
+
const knot_rrset_t *rr_two = knot_pkt_rr(answer, 1);
+ if (answer->count == 2 && rr_one->type == KNOT_RRTYPE_SOA &&
+ knot_rrset_equal(rr_one, rr_two, KNOT_RRSET_COMPARE_WHOLE)) {
+ return XFR_TYPE_AXFR;
+ }
- return (
- rr_one->type == KNOT_RRTYPE_SOA &&
- rr_two->type != KNOT_RRTYPE_SOA
- ) || (
- answer->count == 2 &&
- rr_one->type == KNOT_RRTYPE_SOA &&
- rr_two->type == KNOT_RRTYPE_SOA &&
- knot_rrset_equal(rr_one, rr_two, KNOT_RRSET_COMPARE_WHOLE)
- );
+ return (rr_one->type == KNOT_RRTYPE_SOA && rr_two->type != KNOT_RRTYPE_SOA) ?
+ XFR_TYPE_AXFR : XFR_TYPE_IXFR;
}
static int ixfr_consume(knot_pkt_t *pkt, struct refresh_data *data)
@@ -617,17 +644,37 @@ static int ixfr_consume(knot_pkt_t *pkt, struct refresh_data *data)
if (data->ixfr.proc == NULL) {
const knot_pktsection_t *answer = knot_pkt_section(pkt, KNOT_ANSWER);
- if (!ixfr_check_header(answer)) {
+ data->xfr_type = determine_xfr_type(answer, knot_soa_serial(&data->soa->rrs),
+ data->initial_soa_copy);
+ switch (data->xfr_type) {
+ case XFR_TYPE_ERROR:
IXFRIN_LOG(LOG_WARNING, data->zone->name, data->remote,
- "malformed response");
+ "malformed response SOA");
return KNOT_STATE_FAIL;
- }
-
- if (ixfr_is_axfr(answer)) {
- IXFRIN_LOG(LOG_NOTICE, data->zone->name, data->remote,
+ case XFR_TYPE_UNDETERMINED:
+ // Store the SOA and check with next packet
+ data->initial_soa_copy = knot_rrset_copy(knot_pkt_rr(answer, 0), data->mm);
+ if (data->initial_soa_copy == NULL) {
+ return KNOT_STATE_FAIL;
+ }
+ xfr_stats_add(&data->stats, pkt->size);
+ return KNOT_STATE_CONSUME;
+ case XFR_TYPE_AXFR:
+ IXFRIN_LOG(LOG_INFO, data->zone->name, data->remote,
"receiving AXFR-style IXFR");
- data->is_ixfr = false;
return axfr_consume(pkt, data);
+ case XFR_TYPE_UPTODATE:
+ IXFRIN_LOG(LOG_INFO, data->zone->name, data->remote,
+ "zone is up-to-date");
+ xfr_stats_begin(&data->stats);
+ xfr_stats_add(&data->stats, pkt->size);
+ xfr_stats_end(&data->stats);
+ return KNOT_STATE_DONE;
+ case XFR_TYPE_IXFR:
+ break;
+ default:
+ assert(0);
+ return KNOT_STATE_FAIL;
}
int ret = ixfr_init(data);
@@ -642,9 +689,19 @@ static int ixfr_consume(knot_pkt_t *pkt, struct refresh_data *data)
data->change_size = 0;
}
+ int next;
+ // Process saved SOA if existing
+ if (data->initial_soa_copy != NULL) {
+ next = ixfr_consume_rr(data->initial_soa_copy, data);
+ knot_rrset_free(&data->initial_soa_copy, data->mm);
+ if (next != KNOT_STATE_CONSUME) {
+ return next;
+ }
+ }
+
// Process answer packet
xfr_stats_add(&data->stats, pkt->size);
- int next = ixfr_consume_packet(pkt, data);
+ next = ixfr_consume_packet(pkt, data);
// Finalize
if (next == KNOT_STATE_DONE) {
@@ -712,7 +769,7 @@ static int transfer_produce(knot_layer_t *layer, knot_pkt_t *pkt)
{
struct refresh_data *data = layer->data;
- bool ixfr = data->is_ixfr;
+ bool ixfr = (data->xfr_type == XFR_TYPE_IXFR);
query_init_pkt(pkt);
knot_pkt_put_question(pkt, data->zone->name, KNOT_CLASS_IN,
@@ -733,13 +790,16 @@ static int transfer_consume(knot_layer_t *layer, knot_pkt_t *pkt)
{
struct refresh_data *data = layer->data;
- int next = data->is_ixfr ? ixfr_consume(pkt, data) : axfr_consume(pkt, data);
+ int next = (data->xfr_type == XFR_TYPE_AXFR) ? axfr_consume(pkt, data) :
+ ixfr_consume(pkt, data);
// Transfer completed
if (next == KNOT_STATE_DONE) {
// Log transfer even if we still can fail
xfr_log_finished(data->zone->name,
- data->is_ixfr ? LOG_OPERATION_IXFR : LOG_OPERATION_AXFR,
+ data->xfr_type == XFR_TYPE_IXFR ||
+ data->xfr_type == XFR_TYPE_UPTODATE ?
+ LOG_OPERATION_IXFR : LOG_OPERATION_AXFR,
LOG_DIRECTION_IN, data->remote, &data->stats);
/*
@@ -752,7 +812,17 @@ static int transfer_consume(knot_layer_t *layer, knot_pkt_t *pkt)
}
// Finalize and publish the zone
- int ret = data->is_ixfr ? ixfr_finalize(data) : axfr_finalize(data);
+ int ret;
+ switch (data->xfr_type) {
+ case XFR_TYPE_IXFR:
+ ret = ixfr_finalize(data);
+ break;
+ case XFR_TYPE_AXFR:
+ ret = axfr_finalize(data);
+ break;
+ default:
+ return next;
+ }
if (ret == KNOT_EOK) {
data->updated = true;
} else {
@@ -761,11 +831,11 @@ static int transfer_consume(knot_layer_t *layer, knot_pkt_t *pkt)
}
// IXFR to AXFR failover
- if (data->is_ixfr && next == KNOT_STATE_FAIL) {
+ if (data->xfr_type == XFR_TYPE_IXFR && next == KNOT_STATE_FAIL) {
REFRESH_LOG(LOG_WARNING, data->zone->name, data->remote,
"fallback to AXFR");
ixfr_cleanup(data);
- data->is_ixfr = false;
+ data->xfr_type = XFR_TYPE_AXFR;
return KNOT_STATE_RESET;
}
@@ -779,10 +849,12 @@ static int refresh_begin(knot_layer_t *layer, void *_data)
if (data->soa) {
data->state = STATE_SOA_QUERY;
- data->is_ixfr = true;
+ data->xfr_type = XFR_TYPE_IXFR;
+ data->initial_soa_copy = NULL;
} else {
data->state = STATE_TRANSFER;
- data->is_ixfr = false;
+ data->xfr_type = XFR_TYPE_AXFR;
+ data->initial_soa_copy = NULL;
}
return KNOT_STATE_PRODUCE;
--
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