Commit 3dddcf43 authored by Nick Mathewson's avatar Nick Mathewson 🎨
Browse files

Add lots of logging to dns.c; change behavior of often-failing assertion


svn:r778
parent 24cff42f
......@@ -114,9 +114,14 @@ int dns_resolve(connection_t *exitconn) {
pending_connection->conn = exitconn;
pending_connection->next = resolve->pending_connections;
resolve->pending_connections = pending_connection;
log_fn(LOG_DEBUG,"Connection (fd %d) waiting for pending DNS resolve of '%s'",
exitconn->s, exitconn->address);
return 0;
case CACHE_STATE_VALID:
exitconn->addr = resolve->answer;
log_fn(LOG_DEBUG,"Connection (fd %d) found cached answer for '%s'",
exitconn->s, exitconn->address);
return 1;
case CACHE_STATE_FAILED:
return -1;
......@@ -165,6 +170,9 @@ static int assign_to_dnsworker(connection_t *exitconn) {
return -1;
}
log_fn(LOG_DEBUG, "Connection (fd %d) needs to resolve '%s'; assigning to DNSWorker (fd %d)",
exitconn->s, exitconn->address, dnsconn->s);
free(dnsconn->address);
dnsconn->address = tor_strdup(exitconn->address);
dnsconn->state = DNSWORKER_STATE_BUSY;
......@@ -203,14 +211,19 @@ void dns_cancel_pending_resolve(char *question, connection_t *onlyconn) {
if(pend->conn == onlyconn) {
resolve->pending_connections = pend->next;
free(pend);
if(resolve->pending_connections) /* more pending, don't cancel it */
if(resolve->pending_connections) {/* more pending, don't cancel it */
log_fn(LOG_DEBUG, "Connection (fd %d) no longer waiting for resolve of '%s'",
onlyconn->s, question);
return;
}
} else {
for( ; pend->next; pend = pend->next) {
if(pend->next->conn == onlyconn) {
victim = pend->next;
pend->next = victim->next;
free(victim);
log_fn(LOG_DEBUG, "Connection (fd %d) no longer waiting for resolve of '%s'",
onlyconn->s, question);
return; /* more are pending */
}
}
......@@ -218,6 +231,8 @@ void dns_cancel_pending_resolve(char *question, connection_t *onlyconn) {
}
} else {
/* mark all pending connections to fail */
log_fn(LOG_DEBUG, "Failing all connections waiting on DNS resolve of '%s'",
question);
while(resolve->pending_connections) {
pend = resolve->pending_connections;
connection_edge_end(pend->conn, END_STREAM_REASON_MISC, NULL);
......@@ -257,11 +272,21 @@ static void dns_found_answer(char *question, uint32_t answer) {
resolve = SPLAY_FIND(cache_tree, &cache_root, &search);
if(!resolve) {
log_fn(LOG_WARN,"Answer to unasked question '%s'? Dropping.", question);
/* XXX Why drop? Just because we don't care now doesn't mean we shouldn't
* XXX cache the result for later. */
return;
}
assert(resolve->state == CACHE_STATE_PENDING);
/* XXX sometimes this still gets triggered. :( */
if (resolve->state != CACHE_STATE_PENDING) {
log_fn(LOG_WARN, "Duplicate answer to question '%s'; ignoring",
question);
return;
}
/* Removed this assertion: in fact, we'll sometimes get a double answer
* to the same question. This can happen when we ask one worker to resolve
* X.Y.Z., then we cancel the request, and then we ask another worker to
* resolve X.Y.Z. */
/* assert(resolve->state == CACHE_STATE_PENDING); */
resolve->answer = ntohl(answer);
if(resolve->answer)
......@@ -311,6 +336,9 @@ int connection_dns_process_inbuf(connection_t *conn) {
connection_fetch_from_buf((char*)&answer,sizeof(answer),conn);
log_fn(LOG_DEBUG, "DNSWorker (fd %d) returned answer for '%s'",
conn->s, conn->address);
dns_found_answer(conn->address, answer);
free(conn->address);
......@@ -402,6 +430,10 @@ static void spawn_enough_dnsworkers(void) {
* but no less than min and no more than max */
connection_t *dnsconn;
/* XXX This may not be the best strategy. Maybe we should queue pending
* XXX requests until the old ones finish or time out: otherwise, if
* XXX the connection requests come fast enough, we never get any DNS done.
*/
if(num_dnsworkers_busy == MAX_DNSWORKERS) {
/* We always want at least one worker idle.
* So find the oldest busy worker and kill it.
......@@ -409,6 +441,7 @@ static void spawn_enough_dnsworkers(void) {
dnsconn = connection_get_by_type_state_lastwritten(CONN_TYPE_DNSWORKER, DNSWORKER_STATE_BUSY);
assert(dnsconn);
log_fn(LOG_DEBUG, "Max DNS workers spawned; all are busy. Killing one.");
/* tell the exit connection that it's failed */
dns_cancel_pending_resolve(dnsconn->address, NULL);
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment