simplify loopback case, and remove unused or redundant code

Reference: /n/atom/patch/applied2013/etherloop
Date: Sun Dec 29 17:54:52 CET 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/nix/k10/devether.c	Sun Dec 29 17:54:05 2013
+++ /sys/src/nix/k10/devether.c	Sun Dec 29 17:54:06 2013
@@ -192,21 +192,16 @@
 	pkt = (Etherpkt*)bp->rp;
 	len = BLEN(bp);
 	loopback = memcmp(pkt->d, ether->ea, sizeof(pkt->d)) == 0;
-	if(loopback || memcmp(pkt->d, ether->bcast, sizeof(pkt->d)) == 0 || ether->prom){
-		if(loopback)
-			etheriq(ether, bp, -1);
-		else
-			etheriq(ether, bp, 0);
-	}
-
-	if(!loopback){
-		qbwrite(ether->oq, bp);		/* botch: might block; should track overflows */
-		if(ether->transmit != nil)
-			ether->transmit(ether);
-	}else{
-	//	freeb(bp);
+	if(loopback){
+		etheriq(ether, bp, -1);
+		return len;
 	}
 
+	if(memcmp(pkt->d, ether->bcast, sizeof(pkt->d)) == 0 || ether->prom)
+		etheriq(ether, bp, 0);
+	qbwrite(ether->oq, bp);		/* botch: might block; should track overflows */
+	if(ether->transmit != nil)
+		ether->transmit(ether);
 	return len;
 }
 
@@ -308,29 +303,6 @@
 }
 
 int
-parseether(uchar *to, char *from)
-{
-	char nip[4];
-	char *p;
-	int i;
-
-	p = from;
-	for(i = 0; i < Eaddrlen; i++){
-		if(*p == 0)
-			return -1;
-		nip[0] = *p++;
-		if(*p == 0)
-			return -1;
-		nip[1] = *p++;
-		nip[2] = 0;
-		to[i] = strtoul(nip, 0, 16);
-		if(*p == ':')
-			p++;
-	}
-	return 0;
-}
-
-int
 ethercfgmatch(Ether *e, Pcidev *p, uintmem port)
 {
 	if(e->port == 0 || e->port == port)
@@ -343,7 +315,7 @@
 static Ether*
 etherprobe(int cardno, int ctlrno)
 {
-	char buf[128], name[32], *type, *p, *e;
+	char name[32], *type;
 	int i, j, reset;
 	Ether *ether;
 	extern int eipfmt(Fmt*);
@@ -405,13 +377,8 @@
 	 */
 	if(ether->irq >= 0)
 		ether->vector = intrenable(ether->irq, ether->interrupt, ether, ether->tbdf, name);
-	e = buf + sizeof buf;
-	p = seprint(buf, e, "#l%d: %s: %dMbps port %#p tu %d",
-		ctlrno, cards[cardno].type, ether->mbps, ether->port, ether->mtu);
-	if(ether->mem)
-		p = seprint(p, e, " addr %#p", ether->mem);
-	seprint(p, e, " %E\n", ether->ea);
-	print("%s", buf);
+	print("#l%d: %s: %dMbps port %#p tu %d %E\n",
+		ctlrno, cards[cardno].type, ether->mbps, ether->port, ether->mtu, ether->ea);
 
 	j = ether->mbps;
 	if(j > 1000)
@@ -420,9 +387,9 @@
 		j /= 10;
 	i = 128*1024<<i;
 	netifinit(ether, name, Ntypes, i);
-	if(ether->oq == 0)
+	if(ether->oq == nil)
 		ether->oq = qopen(i, Qmsg, 0, 0);
-	if(ether->oq == 0)
+	if(ether->oq == nil)
 		panic("etherreset %s", name);
 	ether->alen = Eaddrlen;
 	memmove(ether->addr, ether->ea, Eaddrlen);
@@ -479,27 +446,6 @@
 			intrdisable(ether->vector);
 		(*ether->shutdown)(ether);
 	}
-}
-
-
-#define POLY 0xedb88320
-
-/* really slow 32 bit crc for ethers */
-uint
-ethercrc(uchar *p, int len)
-{
-	int i, j;
-	u32int crc, b;
-
-	crc = 0xffffffff;
-	for(i = 0; i < len; i++){
-		b = *p++;
-		for(j = 0; j < 8; j++){
-			crc = (crc>>1) ^ (((crc^b) & 1) ? POLY : 0);
-			b >>= 1;
-		}
-	}
-	return crc;
 }
 
 Dev etherdevtab = {