[HICN-402] Limit in-flight interests for manifests

Currently, interests for manifests are sent independently of the
transport protocol. When receiving a manifest, interests for next
manifests are sent until the next window would be full of data
segments.

But there is no limit on the number of interests for manifests that
can be sent. After a while, the interest input buffer in the
producer's side is full of them and cannot satisfy the requests
quickly enough. This results in a large drop of bandwidth on the
consumer side. This patch allows to limit the number of in-flight
interests for manifests.

Signed-off-by: Olivier Roques <olvrqs@gmail.com>
Change-Id: Ic497bd55fd92233e4b47b04635fb9bf75506375e

1 files changed, 16 insertions, 2 deletions

diff --git a/libtransport/src/hicn/transport/protocols/manifest_indexing_manager.cc b/libtransport/src/hicn/transport/protocols/manifest_indexing_manager.cc
index 9af6a5c3a..05cabc60d 100644
--- a/libtransport/src/hicn/transport/protocols/manifest_indexing_manager.cc
+++ b/libtransport/src/hicn/transport/protocols/manifest_indexing_manager.cc
@@ -29,6 +29,7 @@ ManifestIndexManager::ManifestIndexManager(
     interface::ConsumerSocket *icn_socket, TransportProtocol *next_interest)
     : IncrementalIndexManager(icn_socket),
       PacketManager<Interest>(1024),
+      manifests_in_flight_(0),
       next_reassembly_segment_(suffix_queue_.end()),
       next_to_retrieve_segment_(suffix_queue_.end()),
       suffix_manifest_(core::NextSegmentCalculationStrategy::INCREMENTAL, 0),
@@ -86,7 +87,14 @@ bool ManifestIndexManager::onManifest(
           // Set the iterators to the beginning of the suffix queue
           next_reassembly_segment_ = suffix_queue_.begin();
           // Set number of segments in manifests assuming the first one is full
-          suffix_manifest_.setNbSegments(std::distance(_it, _end) - 1);
+          suffix_manifest_.setNbSegments(
+              std::distance(manifest->getSuffixList().begin(),
+                            manifest->getSuffixList().end()) -
+              1);
+          suffix_manifest_.setSuffixStrategy(
+              manifest->getNextSegmentCalculationStrategy());
+        } else if (manifests_in_flight_) {
+          manifests_in_flight_--;
         }
 
         if (TRANSPORT_EXPECT_FALSE(manifest->isFinalManifest() ||
@@ -110,6 +118,10 @@ bool ManifestIndexManager::onManifest(
         // Manifest namespace
         Name &name = manifest->getWritableName();
 
+        if (manifests_in_flight_ >= MAX_MANIFESTS_IN_FLIGHT) {
+          break;
+        }
+
         // Send as many manifest as required for filling window.
         do {
           segment_count += suffix_manifest_.getNbSegments();
@@ -132,8 +144,10 @@ bool ManifestIndexManager::onManifest(
                         std::placeholders::_1, std::placeholders::_2),
               std::bind(&ManifestIndexManager::onManifestTimeout, this,
                         std::placeholders::_1));
+          manifests_in_flight_++;
         } while (segment_count < current_window_size &&
-                 suffix_manifest_.getSuffix() < final_suffix_);
+                 suffix_manifest_.getSuffix() < final_suffix_ &&
+                 manifests_in_flight_ < MAX_MANIFESTS_IN_FLIGHT);
 
         break;
       }