wifi-diag: Start on block-ack parsing and sanity checks.

wifi_diag/Packet.pm

@@ -8,16 +8,19 @@ sub new {
   my %options = @_;
 
   my $self = {
+	      seqno => -1, # block-ack will not have a seqno
+	      acked_by => -1,
+	      block_acked_by => -1,
 	      retrans => 0,
 	      timestamp => 0,
 	      datarate => 0,
 	      type_subtype => "UNKNOWN",
 	      receiver => "UNKNOWN",
 	      transmitter => "UNKNOWN",
+	      tid => 17, # anything that does not specify a tid gets this.
 	      %options,
 	      amsdu_frame_count => 0,
 	      ssi_sig_found => 0,
-	      tid => 17, # anything that does not specify a tid gets this.
 	     };
 
   bless($self, $class);
@@ -60,9 +63,10 @@ sub append {
     $self->{ba_starting_seq} = $1;
   }
   elsif ($ln =~ /.* = TID for which a Basic BlockAck frame is requested: (\S+)/) {
-    $self->{ba_tid} = $1;
+    $self->{ba_tid} = hex($1);
   }
   elsif ($ln =~ /^\s*Block Ack Bitmap: (\S+)/) {
+    #print "ba-bitmap: $1\n";
     $self->{ba_bitmap} = $1;
   }
   elsif ($ln =~ /.* = Retry: Frame is being retransmitted/) {
@@ -152,6 +156,54 @@ sub retrans {
   return $self->{retrans};
 }
 
+sub seqno {
+  my $self = shift;
+  return $self->{seqno};
+}
+
+sub block_acked_by {
+  my $self = shift;
+  return $self->{block_acked_by};
+}
+
+sub acked_by {
+  my $self = shift;
+  return $self->{acked_by};
+}
+
+sub set_block_acked_by {
+  my $self = shift;
+  $self->{block_acked_by} = shift;
+}
+
+sub set_acked_by {
+  my $self = shift;
+  $self->{acked_by} = shift;
+}
+
+sub was_acked {
+  my $self = shift;
+
+  if ($self->block_acked_by() != -1) {
+    return 1;
+  }
+  if ($self->acked_by() != -1) {
+    return 1;
+  }
+  return 0;
+}
+
+sub wants_ack {
+  my $self = shift;
+  my $rcvr_b0 = substring(self->receiver(), 0, 1);
+  my $rb0 = hex("$rcvr_b0");
+  if ($rb0 & 0x1) {
+    return 0;  # Don't ack bcast/bcast frames
+  }
+  # TODO:  Need to parse QoS no-ack frames too, this will return false positives currently
+  return 1;
+}
+
 sub timestamp {
   my $self = shift;
   return $self->{timestamp};
@@ -164,6 +216,9 @@ sub receiver {
 
 sub tid {
   my $self = shift;
+  if (exists $self->{ba_tid}) {
+    return $self->{ba_tid};
+  }
   return $self->{tid};
 }
 

wifi_diag/Tid.pm

@@ -2,6 +2,9 @@ package Tid;
 
 use warnings;
 use strict;
+use bigint;
+
+my $warn_dup_ba_once = 1;
 
 sub new {
   my $class = shift;
@@ -47,6 +50,99 @@ sub add_pkt {
     $self->{tx_retrans}++;
   }
 
+  my $pkt_count = @{$self->{pkts}};
+
+  # If this is a block-ack, then check for previous frames that would match.
+  if ($pkt->type_subtype() eq "802.11 Block Ack (0x0019)") {
+    my $transmitter = $pkt->transmitter();
+    my $starting_seqno = $pkt->{ba_starting_seq};
+    my $i;
+    my $bitmap = $pkt->{ba_bitmap}; # 0100000000000000 for instance
+    my $bi_as_long = 0;
+    my $bi_mask = 0;
+    my $q;
+    for ($q = 0; $q < 8; $q++) {
+      my $bmap_octet = substr($bitmap, $q * 2, 2);
+      my $bmi = hex($bmap_octet);
+      #print "bmap-octet: $bmap_octet bmi: " . hex($bmi) . "\n";
+      $bi_as_long |= ($bmi << ($q * 8));
+    }
+
+    for ($i = 0; $i<$pkt_count; $i++) {
+      my $tmp = $self->{pkts}[$i];
+      #print "checking tmp-pkt: " . $tmp->seqno();
+      #print " transmitter: " . $tmp->transmitter();
+      #print " pkt-rcvr: " . $pkt->receiver() . "\n";
+      if ($tmp->transmitter() eq $pkt->receiver()) {
+	if ($tmp->seqno() >= $starting_seqno && $tmp->seqno() < ($starting_seqno + 64)) {
+	  # tmp pkt might match this BA bitmap..check closer.
+	  my $diff = $tmp->seqno() - $starting_seqno;
+	  
+	  if ($bi_as_long & (1 << $diff)) {
+	    # Found a matching frame.
+	    $bi_mask |= (1 << $diff);
+
+	    if ($tmp->block_acked_by() != -1) {
+	      # This seems to be a common thing, warn once and not again.
+	      if ($warn_dup_ba_once) {
+		print "WARNING:  block-ack frame: " . $pkt->frame_num() . " acking frame: " .
+		  $tmp->frame_num() . " already block-acked by frame: " . $tmp->block_acked_by() . ".  This warning will not be shown again.\n";
+		$warn_dup_ba_once = 0;
+	      }
+	    }
+	    elsif ($tmp->acked_by() != -1) {
+	      print "WARNING:  block-ack frame: " . $pkt->frame_num() . " acking frame: " .
+		$tmp->frame_num() . " already acked by frame: " . $tmp->acked_by() . "\n";
+	    }
+	    $tmp->set_block_acked_by($pkt->frame_num());
+	  }
+	}
+      }
+    }# for all pkts
+
+    # See if we block-acked anything we could not find?
+    if ($bi_mask != $bi_as_long) {
+      my $missing = $bi_mask ^ $bi_as_long;
+      my $missing_str = "";
+      for ($i = 0; $i<64; $i++) {
+	if ($missing & (1<<$i)) {
+	  my $missing_seqno = $starting_seqno + $i;
+	  $missing_str .= $missing_seqno . " ";
+
+	  # Add a dummy pkt
+	  my $dummy = Packet->new(transmitter => $pkt->receiver(),
+				  data_subtype => "DUMMY_BA_ACKED",
+				  timestamp => $pkt->timestamp(),
+				  seqno => $missing_seqno,
+				  tid => $self->tidno());
+	  $dummy->block_acked_by($pkt->frame_num());
+	  push(@{$self->{pkts}}, $dummy);
+	  #print "pushing dummy pkt, seqno: $missing_seqno\n";
+	}
+      }
+      print "WARNING:  block-ack frame: " . $pkt->frame_num() . " acked frames we did not capture, found-these: " . $bi_mask->as_hex .
+	" acked these: " . $bi_as_long->as_hex . " missing: " . $missing->as_hex . "($missing_str), starting-seq-no: $starting_seqno\n";
+    }
+  }
+
+  # Shift off old frames.
+  while ($pkt_count > 0) {
+    my $tmp = shift(@{$self->{pkts}});
+    if (($tmp->timestamp() + 60 < $pkt->timestamp()) ||
+	($pkt_count > 1000)) {
+      if (! $tmp->was_acked()) {
+	if ($tmp->wants_ack()) {
+	  print "WARNING:  did not find ack for frame: " . $tmp->frame_num() . ", removing after processing frame: " . $pkt->frame_num() . "\n";
+	}
+      }
+      $pkt_count--;
+      next; # Drop frames when we have more than 1000 or they are older than 1 minute ago
+    }
+    # Put this one back on
+    unshift(@{$self->{pkts}}, $tmp);
+    last;
+  }
+
   # Generate reporting data for this pkt
   my $fh = $self->{mcs_fh};
   print $fh "" . $pkt->timestamp() . "\t" . $self->tidno() . "\t" . $pkt->datarate() . "\t" . $pkt->retrans() . "\n";

wifi_diag/wifi_pcap_diag.pl

@@ -56,6 +56,17 @@ sub processPkt {
   if ($pkt->type_subtype() eq "Acknowledgement (0x001d)") {
     if ($last_pkt->transmitter() eq $pkt->receiver()) {
       $pkt->set_transmitter($last_pkt->receiver());
+      if ($last_pkt->acked_by() != -1) {
+	print "WARNING:  ack frame: " . $pkt->frame_num() . " acking frame: " .
+		$last_pkt->frame_num() . " already acked by frame: " . $last_pkt->acked_by() . "\n";
+      }
+      elsif ($last_pkt->block_acked_by() != -1) {
+	print "WARNING:  ack frame: " . $pkt->frame_num() . " acking frame: " .
+		$last_pkt->frame_num() . " already block-acked by frame: " . $last_pkt->block_acked_by() . "\n";
+      }
+      else {
+	$last_pkt->set_acked_by($pkt->frame_num());
+      }
     }
     else {
       print "ERROR:  Frame " . $pkt->frame_num() . " is ACK for unknown packet.\n";