fix shifted frames bug (bad sequence)

AlexVangelov · Aug 21, 2015 · 4e52867 · 4e52867
1 parent 2a3e726
commit 4e52867
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Showing 3 changed files with 52 additions and 18 deletions.
diff --git a/app/models/extface/driver/daisy_fx1200.rb b/app/models/extface/driver/daisy_fx1200.rb
@@ -18,6 +18,7 @@ class Driver::DaisyFx1200 < Extface::Driver::Base::Fiscal
     INVALID_FRAME_RETRIES = 6  #count (bad length, bad checksum)
     ACKS_MAX_WAIT = 60 #count / nothing is forever
     NAKS_MAX_COUNT = 3 #count
+    BAD_SEQ_MAX_COUNT = 3
 
     TAX_GROUPS_MAP = {
       1 => "\xc0",
@@ -243,12 +244,22 @@ def fsend(cmd, data = "") #return data or nil
     end
 
     def frecv(timeout) # return RespFrame or nil
-      if frame_bytes = pull(timeout)
-        return RespFrame.new(frame_bytes.b)
-      else
-        errors.add :base, "No data received from device"
-        return nil
+      rframe = nil
+      BAD_SEQ_MAX_COUNT.times do
+        if frame_bytes = pull(timeout)
+          rframe = RespFrame.new(frame_bytes.b)
+          if rframe.seq.ord == sequence_number(false) #accept only current sequence number as reply
+            break
+          else
+            errors.add :base, "Sequence mismatch"
+            rframe = nil #invalidate mismatch sequence frame for the last retry
+          end
+        else
+          errors.add :base, "No data received from device"
+          break
+        end
       end
+      return rframe
     end
 
     private

diff --git a/app/models/extface/driver/datecs/fp550.rb b/app/models/extface/driver/datecs/fp550.rb
@@ -6,6 +6,7 @@ class Driver::Datecs::Fp550 < Extface::Driver::Base::Fiscal
     INVALID_FRAME_RETRIES = 6  #count (bad length, bad checksum)
     ACKS_MAX_WAIT = 60 #count / nothing is forever
     NAKS_MAX_COUNT = 3 #count
+    BAD_SEQ_MAX_COUNT = 3
 
     TAX_GROUPS_MAP = {
       1 => "\xc0",
@@ -206,13 +207,24 @@ def fsend(cmd, data = "") #return data or nil
       return result
     end
 
-    def frecv(timeout) # return RespFrame or nil
-      if frame_bytes = pull(timeout)
-        return Frame.new(frame_bytes.b)
-      else
-        errors.add :base, "No data received from device"
-        return nil
+    def frecv(timeout) # return Frame or nil
+      rframe = nil
+      BAD_SEQ_MAX_COUNT.times do
+        if frame_bytes = pull(timeout)
+          rframe = Frame.new(frame_bytes.b)
+          if rframe.seq.ord == sequence_number(false) #accept only current sequence number as reply
+            break
+          else
+            errors.add :base, "Sequence mismatch"
+            p "Invalid sequence (expected: #{sequence_number(false).to_s(16)}, got: #{rframe.seq.ord.to_s(16)})"
+            rframe = nil #invalidate mismatch sequence frame for the last retry
+          end
+        else
+          errors.add :base, "No data received from device"
+          break
+        end
       end
+      return rframe
     end
 
     def build_packet(cmd, data = "")
@@ -259,9 +271,9 @@ def build_sale_data(item)
         end
       end
 
-      def sequence_number
+      def sequence_number(increment = true)
         @seq ||= 0x1f
-        @seq += 1
+        @seq += 1 if increment
         @seq = 0x1f if @seq == 0x7f
         @seq
       end

diff --git a/app/models/extface/driver/eltrade_tm_u220.rb b/app/models/extface/driver/eltrade_tm_u220.rb
@@ -11,6 +11,7 @@ class Driver::EltradeTmU220 < Extface::Driver::Base::Fiscal
     RESPONSE_TIMEOUT = 3  #seconds
     INVALID_FRAME_RETRIES = 6  #count
     BUSY_MAX_WAIT_CYCLES = 60  #count
+    BAD_SEQ_MAX_COUNT = 3
 
     FLAG_TRUE = "\xff\xff"
     FLAG_FALSE = "\x00\x00"
@@ -260,12 +261,22 @@ def fsend(cmd, data = "") #return data or nil
     end
 
     def frecv(timeout) # return RespFrame or nil
-      if frame_bytes = pull(timeout)
-        return Frame.new(frame_bytes.b)
-      else
-        errors.add :base, "No data received from device"
-        return nil
+      rframe = nil
+      BAD_SEQ_MAX_COUNT.times do
+        if frame_bytes = pull(timeout)
+          rframe = Frame.new(frame_bytes.b)
+          if rframe.seq.ord == sequence_number(false) #accept only current sequence number as reply
+            break
+          else
+            errors.add :base, "Sequence mismatch"
+            rframe = nil #invalidate mismatch sequence frame for the last retry
+          end
+        else
+          errors.add :base, "No data received from device"
+          break
+        end
       end
+      return rframe
     end
 
     def pbcd(byte)