ip: add checksum computation on ip rx (maybe not optimal on ressources)

diff --git a/liteeth/ip/__init__.py b/liteeth/ip/__init__.py
index 84fd81773a6f7b9143cb64b9e68c25bd31596eed..e495972e7577e42c22c3eb58a82d70b56b96515a 100644 (file)
--- a/liteeth/ip/__init__.py
+++ b/liteeth/ip/__init__.py
@@ -121,6 +121,10 @@ class LiteEthIPRX(Module):
                self.comb += Record.connect(self.sink, depacketizer.sink)
                sink = depacketizer.source
 
+               checksum = LiteEthIPV4Checksum(skip_header=False)
+               self.submodules += checksum
+               self.comb += checksum.header.eq(depacketizer.header)
+
                fsm = FSM(reset_state="IDLE")
                self.submodules += fsm
                fsm.act("IDLE",
@@ -131,7 +135,14 @@ class LiteEthIPRX(Module):
                        )
                )
                valid = Signal()
-               self.comb += valid.eq(1) # XXX FIXME
+               self.comb += valid.eq(
+                       sink.stb &
+                       (sink.destination_ip_address == ip_address) &
+                       (sink.version == 0x4) &
+                       (sink.ihl == 0x5) &
+                       (checksum.value == 0)
+               )
+
                fsm.act("CHECK",
                        If(valid,
                                NextState("PRESENT")