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amc pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/trafficserver.git
The following commit(s) were added to refs/heads/master by this push:
new 6f0bc84 Prevent potential dispatch of HttpTunnel events to a dead
consumer.
6f0bc84 is described below
commit 6f0bc840b2cbfcbead88c4a411dc719c4f9d6f25
Author: Alan M. Carroll <[email protected]>
AuthorDate: Fri Jun 2 13:07:36 2017 -0500
Prevent potential dispatch of HttpTunnel events to a dead consumer.
---
proxy/http/HttpTunnel.h | 30 +++++++++++++++++++++++++-----
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/proxy/http/HttpTunnel.h b/proxy/http/HttpTunnel.h
index 54f5314..2e9d32f 100644
--- a/proxy/http/HttpTunnel.h
+++ b/proxy/http/HttpTunnel.h
@@ -475,12 +475,32 @@ HttpTunnel::get_producer(HttpTunnelType_t type)
inline HttpTunnelConsumer *
HttpTunnel::get_consumer(VConnection *vc)
{
- for (int i = 0; i < MAX_CONSUMERS; i++) {
- if (consumers[i].vc == vc) {
- return consumers + i;
+ /** Rare but persistent problem in which a @c INKVConnInternal is used by a
consumer, released,
+ and then re-allocated for a different consumer. This causes two
consumers to have the same VC
+ pointer resulting in this method returning the wrong consumer. Note this
is a not a bad use of
+ the tunnel, but an unfortunate interaction with the FIFO free lists.
+
+ It's not correct to check for the consumer being alive - at a minimum
`HTTP_TUNNEL_EVENT_DONE`
+ is dispatched against a consumer after the consumer is not alive.
Instead if a non-alive
+ consumer matches it is stored as a candidate and returned if no other
match is found. If a
+ live matching consumer is found, it is immediately returned. It is never
valid to have the
+ same VC in more than one active consumer. This should avoid a
performance impact because in
+ the usual case the consumer will be alive.
+
+ In the case of a deliberate dispatch of an event to a dead consumer that
has a duplicate vc
+ address, this will select the last consumer which will be correct as the
consumers are added
+ in order therefore the latter consumer will be the most recent /
appropriate target.
+ */
+ HttpTunnelConsumer *zret = nullptr;
+ for (HttpTunnelConsumer &c : consumers) {
+ if (c.vc == vc) {
+ zret = &c;
+ if (c.alive) { // a match that's alive is always the best.
+ break;
+ }
}
}
- return NULL;
+ return zret;
}
inline HttpTunnelProducer *
@@ -499,7 +519,7 @@ HttpTunnel::get_consumer(VIO *vio)
{
if (vio) {
for (int i = 0; i < MAX_CONSUMERS; i++) {
- if (consumers[i].write_vio == vio || consumers[i].vc == vio->vc_server) {
+ if (consumers[i].alive && (consumers[i].write_vio == vio ||
consumers[i].vc == vio->vc_server)) {
return consumers + i;
}
}
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