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-rw-r--r--test/vpp_pg_interface.py33
1 files changed, 33 insertions, 0 deletions
diff --git a/test/vpp_pg_interface.py b/test/vpp_pg_interface.py
index 81737c6d567..d6e6684993c 100644
--- a/test/vpp_pg_interface.py
+++ b/test/vpp_pg_interface.py
@@ -1,6 +1,7 @@
import os
import time
import socket
+import struct
from traceback import format_exc, format_stack
from scapy.utils import wrpcap, rdpcap, PcapReader
from scapy.plist import PacketList
@@ -283,6 +284,37 @@ class VppPGInterface(VppInterface):
return False
return True
+ def wait_for_packet_data(self, deadline):
+ """
+ Wait until enough data is available in the file handled by internal
+ pcap reader so that a whole packet can be read.
+
+ :param deadline: timestamp by which the data must arrive
+ :raises Exception: if not enough data by deadline
+ """
+ orig_pos = self._pcap_reader.f.tell() # save file position
+ enough_data = False
+ while time.time() < deadline:
+ # read packet header from pcap
+ hdr = self._pcap_reader.f.read(16)
+ if len(hdr) < 16:
+ time.sleep(0) # yield
+ continue # cannot read full header, continue looping
+ # find the capture length - caplen
+ sec, usec, caplen, wirelen = struct.unpack(
+ self._pcap_reader.endian + "IIII", hdr)
+ self._pcap_reader.f.seek(0, 2) # seek to end of file
+ end_pos = self._pcap_reader.f.tell() # get position at end
+ if end_pos >= orig_pos + len(hdr) + caplen:
+ enough_data = True # yay, we have enough data
+ break
+ self.test.logger.debug("Partial packet data in pcap")
+ time.sleep(0) # yield
+ self._pcap_reader.f.seek(orig_pos, 0) # restore original position
+ if not enough_data:
+ raise Exception(
+ "Not enough data to read a full packet within deadline")
+
def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
"""
Wait for next packet captured with a timeout
@@ -311,6 +343,7 @@ class VppPGInterface(VppInterface):
self.test.logger.debug("Waiting for packet")
while time.time() < deadline:
+ self.wait_for_packet_data(deadline)
p = self._pcap_reader.recv()
if p is not None:
if filter_out_fn is not None and filter_out_fn(p):