From 90abd1902240d74b35b66ff09e5225498e691c50 Mon Sep 17 00:00:00 2001
From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Wed, 4 Feb 2015 20:50:49 +0100
Subject: [PATCH] udp: add skeleton

---
 liteeth/common.py   |  11 +++++
 liteeth/core/ip.py  |   1 -
 liteeth/core/udp.py | 103 +++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 112 insertions(+), 3 deletions(-)

diff --git a/liteeth/common.py b/liteeth/common.py
index ec006492..5c5b06ec 100644
--- a/liteeth/common.py
+++ b/liteeth/common.py
@@ -149,6 +149,17 @@ def eth_udp_description(dw):
 	]
 	return EndpointDescription(layout, packetized=True)
 
+def eth_udp_user_description(dw):
+	layout = [
+		("source_port", 16),
+		("destination_port", 16),
+		("ip_address", 32),
+		("length", 16),
+		("data", dw),
+		("error", dw//8)
+	]
+	return EndpointDescription(layout, packetized=True)
+
 # Generic modules
 @DecorateModule(InsertReset)
 @DecorateModule(InsertCE)
diff --git a/liteeth/core/ip.py b/liteeth/core/ip.py
index e495972e..d1978682 100644
--- a/liteeth/core/ip.py
+++ b/liteeth/core/ip.py
@@ -104,7 +104,6 @@ class LiteEthIPTX(Module):
 			self.source.ethernet_type.eq(ethernet_type_ip),
 			self.source.destination_mac_address.eq(destination_mac_address),
 			self.source.source_mac_address.eq(mac_address),
-			# XXX compute check sum
 			If(self.source.stb & self.source.eop & self.source.ack,
 				# XXX manage failed
 				NextState("IDLE")
diff --git a/liteeth/core/udp.py b/liteeth/core/udp.py
index 296abe6d..b4afd936 100644
--- a/liteeth/core/udp.py
+++ b/liteeth/core/udp.py
@@ -5,7 +5,7 @@ from liteeth.generic.packetizer import LiteEthPacketizer
 class LiteEthUDPDepacketizer(LiteEthDepacketizer):
 	def __init__(self):
 		LiteEthDepacketizer.__init__(self,
-			eth_ipv4_description(8),
+			eth_ipv4_user_description(8),
 			eth_udp_description(8),
 			udp_header,
 			udp_header_len)
@@ -14,6 +14,105 @@ class LiteEthUDPPacketizer(LiteEthPacketizer):
 	def __init__(self):
 		LiteEthPacketizer.__init__(self,
 			eth_udp_description(8),
-			eth_ipv4_description(8),
+			eth_ipv4_user_description(8),
 			udp_header,
 			udp_header_len)
+
+class LiteEthUDPTX(Module):
+	def __init__(self, ip_address):
+		self.sink = Sink(eth_udp_user_description(8))
+		self.source = Source(eth_ipv4_user_description(8))
+		###
+		packetizer = LiteEthUDPV4Packetizer()
+		self.submodules += packetizer
+		self.comb += [
+			packetizer.sink.stb.eq(self.sink.stb),
+			packetizer.sink.sop.eq(self.sink.sop),
+			packetizer.sink.eop.eq(self.sink.eop),
+			self.sink.eq(packetizer.sink.ack),
+			packetizer.sink.source_port.eq(self.sink.source_port),
+			packetizer.sink.destination_port.eq(self.sink.destination_port),
+			packetizer.sink.length.eq(self.sink.length + udp_header_len),
+			packetizer.sink.checksum.eq(0),
+		]
+		sink = packetizer.source
+
+		fsm = FSM(reset_state="IDLE")
+		self.submodules += fsm
+		fsm.act("IDLE",
+			sink.ack.eq(1),
+			If(sink.stb & sink.sop,
+				sink.ack.eq(0),
+				NextState("SEND")
+			)
+		)
+		fsm.act("SEND",
+			Record.connect(packetizer.source, self.source),
+			self.source.length.eq(),
+			self.source.protocol.eq(udp_protocol),
+			self.source.ip_address.eq(self.sink.ip_address),
+			If(self.source.stb & self.source.eop & self.source.ack,
+				NextState("IDLE")
+			)
+		)
+
+class LiteEthUDPRX(Module):
+	def __init__(self, ip_address):
+		self.sink = Sink(eth_ipv4_user_description(8))
+		self.source = source = Source(eth_udp_user_description(8))
+		###
+		depacketizer = LiteEthUDPV4Depacketizer()
+		self.submodules += depacketizer
+		self.comb += Record.connect(self.sink, depacketizer.sink)
+		sink = depacketizer.source
+
+		fsm = FSM(reset_state="IDLE")
+		self.submodules += fsm
+		fsm.act("IDLE",
+			sink.ack.eq(1),
+			If(sink.stb & sink.sop,
+				sink.ack.eq(0),
+				NextState("CHECK")
+			)
+		)
+		valid = Signal()
+		self.comb += valid.eq(
+			sink.stb &
+			(sink.protocol == udp_protocol) &
+			(sink.ip_address == ip_address)
+		)
+
+		fsm.act("CHECK",
+			If(valid,
+				NextState("PRESENT")
+			).Else(
+				NextState("DROP")
+			)
+		),
+		fsm.act("PRESENT",
+			source.stb.eq(sink.stb),
+			source.sop.eq(sink.sop),
+			source.eop.eq(sink.eop),
+			sink.ack.eq(source.ack),
+			source.source_port.eq(sink.source_port),
+			source.destination_port.eq(sink.destination_port),
+			source.ip_address.eq(0),
+			source.length.eq(sink.length - udp_header_len),
+			source.data.eq(sink.data),
+			source.error.eq(sink.error),
+			If(source.stb & source.eop & source.ack,
+				NextState("IDLE")
+			)
+		)
+		fsm.act("DROP",
+			sink.ack.eq(1),
+			If(source.stb & source.eop & source.ack,
+				NextState("IDLE")
+			)
+		)
+
+class LiteEthUDP(Module):
+	def __init__(self, ip_address):
+		self.submodules.tx = LiteEthUDPTX(ip_address)
+		self.submodules.rx = LiteEthUDPRX(ip_address)
+		self.sink, self.source = self.tx.sink, self.rx.source
-- 
2.30.2