From a93bea20e1eeb16ad3c415c3dcfb0eef9a7e9d91 Mon Sep 17 00:00:00 2001
From: Adam Sampson <ats@offog.org>
Date: Thu, 9 Aug 2018 01:42:12 +0100
Subject: [PATCH] WIP: Produces an ARP reply that slirp responds to!

---
 src/system/ether.1 | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/src/system/ether.1 b/src/system/ether.1
index 0a7fecc1..4ed04e93 100644
--- a/src/system/ether.1
+++ b/src/system/ether.1
@@ -22,10 +22,10 @@
 %NE8==377
 
 .BEGIN %NEH			;Fields in the Ethernet header
- LENGTH==<2+6+6+2>
+ PAD==2				;padding at start of buffer
+ LENGTH==<PAD+6+6+2>
  WORDS==<LENGTH/4>
 
- PAD==<.BP <%NE16_20.>,0>
 ;FIXME Would all the MAC stuff be easier if this was 3 16-bit fields?
  DMAC0==<.BP <%NE16_4>,0>
  DMAC12==<.BP <%NE32_4>,1>
@@ -99,6 +99,7 @@ IPKSNE:	BUG INFO,[ipksne]
 ETHRX:	MOVEI TT,ETHHBF		;Unpack Ethernet header into ETHHBF
 	HRL TT,R
 	BLTUB TT,<ETHHBF+%NEH"WORDS-1>
+	BUG INFO,[RX packet length ],OCT,I,[ ptr ],OCT,R
 	SUBI I,%NEH"LENGTH	;I now contains data length
 	ADDI R,%NEH"WORDS	;R points to data
 
@@ -113,7 +114,8 @@ ETHRX:	MOVEI TT,ETHHBF		;Unpack Ethernet header into ETHHBF
 
 ;Process an ARP packet.
 ;
-ETHRXA:	CAIN I,%NEAH"LENGTH	;Check size first
+ETHRXA:	BUG INFO,[ARP length ],OCT,I
+	CAIGE I,%NEAH"LENGTH	;Check size first
 	 JRST ETHRAS
 
 	MOVEI TT,ETHABF		;Unpack packet into ETHABF
@@ -195,7 +197,7 @@ ETHRX3: DPB A,[%NEAT"PA+ETHAT(E)]	;Store IP address
 	MOVEI I,%NEAH"LENGTH
 	JRST ETHTX
 
-ETHRAS:	BUG INFO,[ARP wrong size packet ],OCT,I
+ETHRAS:	BUG INFO,[ARP packet too short, length ],OCT,I
 	POPJ P,
 ETHRAH:	BUG INFO,[ARP wrong hardware type ],OCT,B
 	POPJ P,
@@ -227,14 +229,14 @@ ETHTX:	BUG INFO,[ethtx ptr ],OCT,R,[ len ],OCT,I
 	HRL TT,R
 	MOVE A,I
 	ADDI A,3
-	IDIVI A,4
+	LSH A,-2
 	ADD A,B
-	MOVE C,TT
-	BUG INFO,[ethtx bltbu tt ],OCT,C,[ a ],OCT,A
+	MOVE C,TT	;XXX
+	BUG INFO,[ethtx data bltbu tt ],OCT,C,[ a ],OCT,A
 	BLTBU TT,(A)
 
-	ADDI I,%NEH"LENGTH		;Add length of header
-	BUG INFO,[ethtx end buf ],OCT,B,[ desc ],OCT,D,[ len ],OCT,I
+	ADDI I,%NEH"LENGTH-%NEH"PAD	;Add length of header
+	BUG INFO,[ethtx end desc ],OCT,D,[ len ],OCT,I
 	JRST UNATX			;Transmit it
 
 ;Check whether the interface is able to send a packet.
@@ -396,7 +398,7 @@ IFE 0,[
 	SETZM C			;Buffer index
 
 UNAIN2: MOVE TT,C		;Work out index into UNPAGS/UNPAGU
-	IDIVI TT,2
+	LSH TT,-1
 	AOS TT
 	HLRZ B,UNPAGU(TT)	;Get Unibus addr. Even on the left...
 	TRNE C,1
@@ -412,7 +414,7 @@ UNAIN2: MOVE TT,C		;Work out index into UNPAGS/UNPAGU
 	MOVE A,UNTXRP(C)
 	;BUG INFO,[ring],OCT,C,[ptr],OCT,A
 
-	MOVSI A,%UNBSZ		;SLEN (only useful for recv at this point)
+	MOVSI A,%UNBSZ		;SLEN (only used for recv)
 	HRR A,B			;SEGB low bits
 	MOVEM A,0(D)
 	;BUG INFO,[t/rdr ],OCT,C,[ at ],OCT,D,[ 0/1 = ],OCT,A
@@ -560,6 +562,7 @@ UNARX1:	HRRZ A,W		;Wrap index around
 
 	HRRZ R,UNRXRP(W)	;Buffer
 	LDB I,[.BP 7777,1(J)]	;Get MLEN
+	SUBI I,4		;Ignore CRC at end
 	PUSHJ P,ETHRX
 
 UNARX3:	TLO Q,%UNTD"OWN		;Set OWN=1 to mark as free
@@ -610,11 +613,11 @@ UNAFF1:	HRRZ A,E		;Wrap index around
 	AOS (P)			;Skip return
 	POPJ P,
 
-;Transmit a packet from a buffer obtained by UNAFF.
-;Descriptor in D, buffer in B, data length in bytes in I.
+;Transmit a packet from a descriptor obtained by UNAFF.
+;Descriptor in D, data length in bytes in I.
 ;Clobbers A.
 ;
-UNATX:	BUG INFO,[unatx desc ],OCT,D,[ buff ],OCT,B,[ length ],OCT,I
+UNATX:	BUG INFO,[unatx desc ],OCT,D,[ length ],OCT,I
 	HRLM I,0(D)			;Set SLEN
 	MOVSI A,%UNTD"OWN+%UNTD"STF+%UNTD"ENF
 	IORM A,1(D)			;Set flags