From 6b38e52e4b38370d3097a32550ba9cace6782888 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Wed, 28 Sep 2022 19:17:56 +0000
Subject: devip: get rid of Ipifc.mintu

All the mediums we have implemented know their minimum
transmit unit. The minimum transfer unit is not adjustable
so there is no point in caching it in the ip interface.
---
 sys/src/9/ip/ethermedium.c | 64 +++++++++++++++++++++++-----------------------
 1 file changed, 32 insertions(+), 32 deletions(-)

(limited to 'sys/src/9/ip/ethermedium.c')

diff --git a/sys/src/9/ip/ethermedium.c b/sys/src/9/ip/ethermedium.c
index 19cc65eb7..3a1c65100 100644
--- a/sys/src/9/ip/ethermedium.c
+++ b/sys/src/9/ip/ethermedium.c
@@ -9,6 +9,11 @@
 #include "ip.h"
 #include "ipv6.h"
 
+enum {
+	EHSIZE = 14,
+	EMINTU = 60,
+};
+
 typedef struct Etherhdr Etherhdr;
 struct Etherhdr
 {
@@ -26,6 +31,7 @@ static void	etheraddmulti(Ipifc *ifc, uchar *a, uchar *ia);
 static void	etherremmulti(Ipifc *ifc, uchar *a, uchar *ia);
 static void	etherareg(Fs *f, Ipifc *ifc, Iplifc *lifc, uchar *ip);
 static Block*	multicastarp(Fs *f, Arpent *a, uchar *mac, Routehint *rh);
+static Block*	newEARP(void);
 static void	sendarpreq(Fs *f, Arpent *a);
 static int	multicastea(uchar *ea, uchar *ip);
 static void	recvarpproc(void*);
@@ -34,8 +40,8 @@ static void	etherpref2addr(uchar *pref, uchar *ea);
 Medium ethermedium =
 {
 .name=		"ether",
-.hsize=		14,
-.mintu=		60,
+.hsize=		EHSIZE,
+.mintu=		EMINTU,
 .maxtu=		1514,
 .maclen=	6,
 .bind=		etherbind,
@@ -50,8 +56,8 @@ Medium ethermedium =
 Medium gbemedium =
 {
 .name=		"gbe",
-.hsize=		14,
-.mintu=		60,
+.hsize=		EHSIZE,
+.mintu=		EMINTU,
 .maxtu=		9014,
 .maclen=	6,
 .bind=		etherbind,
@@ -279,9 +285,9 @@ etherbwrite(Ipifc *ifc, Block *bp, int version, uchar *ip, Routehint *rh)
 	assert(bp->list == nil);
 
 	/* make it a single block with space for the ether header */
-	bp = padblock(bp, ifc->m->hsize);
-	if(BLEN(bp) < ifc->mintu)
-		bp = adjustblock(bp, ifc->mintu);
+	bp = padblock(bp, EHSIZE);
+	if(BLEN(bp) < EMINTU)
+		bp = adjustblock(bp, EMINTU);
 	eh = (Etherhdr*)bp->rp;
 
 	/* copy in mac addresses and ether type */
@@ -330,10 +336,10 @@ etherread4(void *a)
 			nexterror();
 		}
 		ifc->in++;
-		if(ifc->lifc == nil || BLEN(bp) <= ifc->m->hsize)
+		if(ifc->lifc == nil || BLEN(bp) <= EHSIZE)
 			freeb(bp);
 		else {
-			bp->rp += ifc->m->hsize;
+			bp->rp += EHSIZE;
 			ipiput4(er->f, ifc, bp);
 		}
 		runlock(ifc);
@@ -368,10 +374,10 @@ etherread6(void *a)
 			nexterror();
 		}
 		ifc->in++;
-		if(ifc->lifc == nil || BLEN(bp) <= ifc->m->hsize)
+		if(ifc->lifc == nil || BLEN(bp) <= EHSIZE)
 			freeb(bp);
 		else {
-			bp->rp += ifc->m->hsize;
+			bp->rp += EHSIZE;
 			ipiput6(er->f, ifc, bp);
 		}
 		runlock(ifc);
@@ -425,6 +431,17 @@ etherremmulti(Ipifc *ifc, uchar *a, uchar *)
 	}
 }
 
+static Block*
+newEARP(void)
+{
+	Block *bp;
+
+	bp = allocb(EMINTU);
+	bp->wp += EMINTU;
+	memset(bp->rp, 0, EMINTU);
+	return bp;
+}
+
 /*
  *  send an ethernet arp
  *  (only v4, v6 uses the neighbor discovery, rfc1970)
@@ -432,7 +449,6 @@ etherremmulti(Ipifc *ifc, uchar *a, uchar *)
 static void
 sendarpreq(Fs *f, Arpent *a)
 {
-	int n;
 	Block *bp;
 	Etherarp *e;
 	Ipifc *ifc = a->ifc;
@@ -445,12 +461,8 @@ sendarpreq(Fs *f, Arpent *a)
 	if(!ipv4local(ifc, src, 0, targ))
 		return;
 
-	n = sizeof(Etherarp);
-	if(n < ifc->m->mintu)
-		n = ifc->m->mintu;
-	bp = allocb(n);
+	bp = newEARP();
 	e = (Etherarp*)bp->rp;
-	memset(e, 0, n);
 	memmove(e->tpa, targ, sizeof(e->tpa));
 	memmove(e->spa, src, sizeof(e->spa));
 	memmove(e->sha, ifc->mac, sizeof(e->sha));
@@ -463,7 +475,6 @@ sendarpreq(Fs *f, Arpent *a)
 	e->hln = sizeof(e->sha);
 	e->pln = sizeof(e->spa);
 	hnputs(e->op, ARPREQUEST);
-	bp->wp += n;
 
 	devtab[er->achan->type]->bwrite(er->achan, bp, 0);
 }
@@ -474,17 +485,12 @@ sendarpreq(Fs *f, Arpent *a)
 static void
 sendgarp(Ipifc *ifc, uchar *ip)
 {
-	int n;
 	Block *bp;
 	Etherarp *e;
 	Etherrock *er = ifc->arg;
 
-	n = sizeof(Etherarp);
-	if(n < ifc->m->mintu)
-		n = ifc->m->mintu;
-	bp = allocb(n);
+	bp = newEARP();
 	e = (Etherarp*)bp->rp;
-	memset(e, 0, n);
 	memmove(e->tpa, ip+IPv4off, sizeof(e->tpa));
 	memmove(e->spa, ip+IPv4off, sizeof(e->spa));
 	memmove(e->sha, ifc->mac, sizeof(e->sha));
@@ -497,7 +503,6 @@ sendgarp(Ipifc *ifc, uchar *ip)
 	e->hln = sizeof(e->sha);
 	e->pln = sizeof(e->spa);
 	hnputs(e->op, ARPREQUEST);
-	bp->wp += n;
 
 	devtab[er->achan->type]->bwrite(er->achan, bp, 0);
 }
@@ -505,7 +510,7 @@ sendgarp(Ipifc *ifc, uchar *ip)
 static void
 recvarp(Ipifc *ifc)
 {
-	int n, forme;
+	int forme;
 	Block *ebp, *rbp;
 	Etherarp *e, *r;
 	uchar ip[IPaddrlen];
@@ -581,12 +586,8 @@ recvarp(Ipifc *ifc)
 		if(arpenter(er->f, V4, e->spa, e->sha, sizeof(e->sha), e->tpa, ifc, !forme) < 0 || !forme)
 			break;
 
-		n = sizeof(Etherarp);
-		if(n < ifc->mintu)
-			n = ifc->mintu;
-		rbp = allocb(n);
+		rbp = newEARP();
 		r = (Etherarp*)rbp->rp;
-		memset(r, 0, n);
 		hnputs(r->type, ETARP);
 		hnputs(r->hrd, 1);
 		hnputs(r->pro, ETIP4);
@@ -599,7 +600,6 @@ recvarp(Ipifc *ifc)
 		memmove(r->spa, e->tpa, sizeof(r->spa));
 		memmove(r->d, e->sha, sizeof(r->d));
 		memmove(r->s, ifc->mac, sizeof(r->s));
-		rbp->wp += n;
 
 		runlock(ifc);
 		freeb(ebp);
-- 
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