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.

4 files changed, 32 insertions, 37 deletions

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);
diff --git a/sys/src/9/ip/ip.h b/sys/src/9/ip/ip.h
index 56d94d4cf..bf4b2cea3 100644
--- a/sys/src/9/ip/ip.h
+++ b/sys/src/9/ip/ip.h
@@ -378,7 +378,6 @@ struct Ipifc
 	char	dev[64];	/* device we're attached to */
 	Medium	*m;		/* Media pointer */
 	int	maxtu;		/* Maximum transfer unit */
-	int	mintu;		/* Minumum tranfer unit */
 	void	*arg;		/* medium specific */
 
 	uchar	reflect;	/* allow forwarded packets to go out the same interface */
diff --git a/sys/src/9/ip/ipifc.c b/sys/src/9/ip/ipifc.c
index 653fd1117..18d9cfeec 100644
--- a/sys/src/9/ip/ipifc.c
+++ b/sys/src/9/ip/ipifc.c
@@ -180,7 +180,6 @@ ipifcbind(Conv *c, char **argv, int argc)
 
 	/* set up parameters */
 	ifc->m = m;
-	ifc->mintu = ifc->m->mintu;
 	ifc->maxtu = ifc->m->maxtu;
 	ifc->delay = 40;
 	ifc->speed = 0;
diff --git a/sys/src/9/ip/netdevmedium.c b/sys/src/9/ip/netdevmedium.c
index f60d43b3a..9ad95b40e 100644
--- a/sys/src/9/ip/netdevmedium.c
+++ b/sys/src/9/ip/netdevmedium.c
@@ -93,9 +93,6 @@ netdevbwrite(Ipifc *ifc, Block *bp, int, uchar*, Routehint*)
 {
 	Netdevrock *er = ifc->arg;
 
-	if(BLEN(bp) < ifc->mintu)
-		bp = adjustblock(bp, ifc->mintu);
-
 	devtab[er->mchan->type]->bwrite(er->mchan, bp, 0);
 	ifc->out++;
 }