GPL: Replace contribution from Lucian

We need to replace the contribution, because Lucian is not responding,
and thus preventing us to use the new license on his code [0].

See the chain leading to [1] on how this reverts
his contribution, and adds a new fix.
Unfortunately we cannot merge that chain one-by-one,
because Python version is different now,
so verify fails for intermediate changes.

This is the chain squashed into the single change,
so it can be verified and merged.

[0] https://gerrit.fd.io/r/c/csit/+/11530
[1] https://gerrit.fd.io/r/c/csit/+/29481/2

Change-Id: I00ab3786e1d9abc28fed778b36d814d293c49383
Signed-off-by: Vratko Polak <vrpolak@cisco.com>

1 files changed, 19 insertions, 12 deletions

diff --git a/GPL/traffic_scripts/PacketVerifier.py b/GPL/traffic_scripts/PacketVerifier.py
index 9b21fea4d9..e05084d66c 100644
--- a/GPL/traffic_scripts/PacketVerifier.py
+++ b/GPL/traffic_scripts/PacketVerifier.py
@@ -208,7 +208,11 @@ class RxQueue(PacketVerifier):
 
         Returns scapy's Ether() object created from next packet in the queue.
         Queue is being filled in parallel in subprocess. If no packet
-        arrives in given timeout queue.Empty exception will be risen.
+        arrives in given timeout None is returned.
+
+        If the list of packets to ignore is given, they are logged
+        but otherwise ignored upon arrival, not adding to the timeout.
+        Each time a packet is ignored, it is removed from the ignored list.
 
         :param timeout: How many seconds to wait for next packet.
         :param ignore: List of packets that should be ignored.
@@ -220,16 +224,19 @@ class RxQueue(PacketVerifier):
         :returns: Ether() initialized object from packet data.
         :rtype: scapy.Ether
         """
-        ignore_list = list()
-        if ignore is not None:
-            for ig_pkt in ignore:
-                # Auto pad all packets in ignore list
-                ignore_list.append(str(auto_pad(ig_pkt)))
-        while True:
-            rlist, _, _ = select.select([self._sock], [], [], timeout)
-            if self._sock not in rlist:
+        time_end = time.monotonic() + timeout
+        ignore = ignore if ignore else list()
+        # Auto pad all packets in ignore list
+        ignore = [str(auto_pad(ig_pkt)) for ig_pkt in ignore]
+        while 1:
+            time_now = time.monotonic()
+            if time_now >= time_end:
                 return None
-
+            timedelta = time_end - time_now
+            rlist, _, _ = select.select([self._sock], [], [], timedelta)
+            if self._sock not in rlist:
+                # Might have been an interrupt.
+                continue
             pkt = self._sock.recv(0x7fff)
             pkt_pad = str(auto_pad(pkt))
             print(f"Received packet on {self._ifname} of len {len(pkt)}")
@@ -240,8 +247,8 @@ class RxQueue(PacketVerifier):
                     # Never happens in practice, but Pylint does not know that.
                     print(f"Unexpected instance: {pkt!r}")
                 print()
-            if pkt_pad in ignore_list:
-                ignore_list.remove(pkt_pad)
+            if pkt_pad in ignore:
+                ignore.remove(pkt_pad)
                 print(u"Received packet ignored.")
                 continue
             return pkt