picnoir
/
Systemd
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

resolved: for a transaction, keep track where the answer data came from 

Let's track where the data came from: from the network, the cache or the
local zone. This is not only useful for debugging purposes, but is also
useful when the zone probing wants to ensure it's not reusing
transactions that were answered from the cache or the zone itself.
This commit is contained in:
Lennart Poettering 2015-11-26 23:33:55 +01:00
parent ae6a4bbf31
commit c3bc53e624
3 changed files with 31 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/resolve/resolved-dns-scope.c
View File

@ -661,7 +661,7 @@ DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsResourceKey *key,
* data instead of a real packet, if that's requested. */
if (!cache_ok &&
IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE) &&
!t->received)
t->answer_source != DNS_TRANSACTION_NETWORK)
return NULL;
return t;

18
src/resolve/resolved-dns-transaction.c
View File

@ -103,6 +103,7 @@ int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key)
return -ENOMEM;
t->dns_udp_fd = -1;
t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID;
t->key = dns_resource_key_ref(key);
/* Find a fresh, unused transaction id */
@ -197,11 +198,12 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) {
* should hence not attempt to access the query or transaction
* after calling this function. */
log_debug("Transaction on scope %s on %s/%s now complete with <%s>",
log_debug("Transaction on scope %s on %s/%s now complete with <%s> from %s",
dns_protocol_to_string(t->scope->protocol),
t->scope->link ? t->scope->link->name : "*",
t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family),
dns_transaction_state_to_string(state));
dns_transaction_state_to_string(state),
t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source));
t->state = state;
@ -392,6 +394,8 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
t->received = dns_packet_ref(p);
}
t->answer_source = DNS_TRANSACTION_NETWORK;
if (p->ipproto == IPPROTO_TCP) {
if (DNS_PACKET_TC(p)) {
/* Truncated via TCP? Somebody must be fucking with us */
@ -637,6 +641,7 @@ int dns_transaction_go(DnsTransaction *t) {
t->received = dns_packet_unref(t->received);
t->answer = dns_answer_unref(t->answer);
t->answer_rcode = 0;
t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID;
/* Check the zone, but obly if this transaction is not used
* for probing or verifying a zone item. */
@ -647,6 +652,7 @@ int dns_transaction_go(DnsTransaction *t) {
return r;
if (r > 0) {
t->answer_rcode = DNS_RCODE_SUCCESS;
t->answer_source = DNS_TRANSACTION_ZONE;
dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);
return 0;
}
@ -668,6 +674,7 @@ int dns_transaction_go(DnsTransaction *t) {
if (r < 0)
return r;
if (r > 0) {
t->answer_source = DNS_TRANSACTION_CACHE;
if (t->answer_rcode == DNS_RCODE_SUCCESS)
dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);
else
@ -771,3 +778,10 @@ static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX]
[DNS_TRANSACTION_ABORTED] = "aborted",
};
DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState);
static const char* const dns_transaction_source_table[_DNS_TRANSACTION_SOURCE_MAX] = {
[DNS_TRANSACTION_NETWORK] = "network",
[DNS_TRANSACTION_CACHE] = "cache",
[DNS_TRANSACTION_ZONE] = "zone",
};
DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source, DnsTransactionSource);

15
src/resolve/resolved-dns-transaction.h
View File

@ -23,6 +23,7 @@
typedef struct DnsTransaction DnsTransaction;
typedef enum DnsTransactionState DnsTransactionState;
typedef enum DnsTransactionSource DnsTransactionSource;
enum DnsTransactionState {
DNS_TRANSACTION_NULL,
@ -39,6 +40,14 @@ enum DnsTransactionState {
_DNS_TRANSACTION_STATE_INVALID = -1
};
enum DnsTransactionSource {
DNS_TRANSACTION_NETWORK,
DNS_TRANSACTION_CACHE,
DNS_TRANSACTION_ZONE,
_DNS_TRANSACTION_SOURCE_MAX,
_DNS_TRANSACTION_SOURCE_INVALID = -1
};
#include "resolved-dns-answer.h"
#include "resolved-dns-packet.h"
#include "resolved-dns-question.h"
@ -58,6 +67,7 @@ struct DnsTransaction {
DnsAnswer *answer;
int answer_rcode;
DnsTransactionSource answer_source;
usec_t start_usec;
sd_event_source *timeout_event_source;
@ -98,6 +108,9 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
/* LLMNR Jitter interval, see RFC 4795 Section 7 */
#define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
@ -107,4 +120,4 @@ DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
/* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
#define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
#define TRANSACTION_ATTEMPTS_MAX(p) (p == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)
#define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)