From a25418fddcf958c8a585779c7642bb88ceaf3f66 Mon Sep 17 00:00:00 2001
From: mischief <mischief@offblast.org>
Date: Sat, 17 Nov 2018 17:23:56 -0800
Subject: [PATCH] devbridge: fix runt packets going through the bridge (thanks
 cinap)

linux will send small, unpadded arp packets which may arrive over
wifi, so allow small packets into the bridge and pad any packets that
are too small when going out.
---
 sys/src/9/port/devbridge.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sys/src/9/port/devbridge.c b/sys/src/9/port/devbridge.c
index bc4537270..3b8ca9037 100644
--- a/sys/src/9/port/devbridge.c
+++ b/sys/src/9/port/devbridge.c
@@ -965,7 +965,7 @@ etherread(void *a)
 		if(bp == nil)
 			break;
 		n = BLEN(bp);
-		if(port->closed || n < ETHERMINTU){
+		if(port->closed || n < ETHERHDRSIZE){
 			freeb(bp);
 			continue;
 		}
@@ -1056,6 +1056,9 @@ etherwrite(Port *port, Block *bp)
 	epkt = (Etherpkt*)bp->rp;
 	if(port->type != Ttun || !fragment(epkt, n)) {
 		if(!waserror()){
+			/* don't generate small packets */
+			if(n < ETHERMINTU)
+				bp = adjustblock(bp, ETHERMINTU);
 			devtab[port->data[1]->type]->bwrite(port->data[1], bp, 0);
 			poperror();
 		}