patch-2.3.36 linux/drivers/net/arcnet/rfc1201.c

• Lines: 537
• Date: Tue Jan 4 09:41:45 2000
• Orig file: v2.3.35/linux/drivers/net/arcnet/rfc1201.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.35/linux/drivers/net/arcnet/rfc1201.c linux/drivers/net/arcnet/rfc1201.c
@@ -0,0 +1,536 @@
+/*
+ * Linux ARCnet driver - RFC1201 (standard) packet encapsulation
+ * 
+ * Written 1994-1999 by Avery Pennarun.
+ * Derived from skeleton.c by Donald Becker.
+ *
+ * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
+ *  for sponsoring the further development of this driver.
+ *
+ * **********************
+ *
+ * The original copyright of skeleton.c was as follows:
+ *
+ * skeleton.c Written 1993 by Donald Becker.
+ * Copyright 1993 United States Government as represented by the
+ * Director, National Security Agency.  This software may only be used
+ * and distributed according to the terms of the GNU Public License as
+ * modified by SRC, incorporated herein by reference.
+ *
+ * **********************
+ *
+ * For more details, see drivers/net/arcnet.c
+ *
+ * **********************
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/if_arp.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/arcdevice.h>
+
+#define VERSION "arcnet: RFC1201 \"standard\" (`a') encapsulation support loaded.\n"
+
+
+static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev);
+static void rx(struct net_device *dev, int bufnum,
+	       struct archdr *pkthdr, int length);
+static int build_header(struct sk_buff *skb, unsigned short type,
+			uint8_t daddr);
+static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
+		      int bufnum);
+static int continue_tx(struct net_device *dev, int bufnum);
+
+struct ArcProto rfc1201_proto =
+{
+	'a',
+	1500,			/* could be more, but some receivers can't handle it... */
+	rx,
+	build_header,
+	prepare_tx,
+	continue_tx
+};
+
+
+void __init arcnet_rfc1201_init(void)
+{
+	arc_proto_map[ARC_P_IP]
+	    = arc_proto_map[ARC_P_ARP]
+	    = arc_proto_map[ARC_P_RARP]
+	    = arc_proto_map[ARC_P_IPX]
+	    = arc_proto_map[ARC_P_NOVELL_EC]
+	    = &rfc1201_proto;
+
+	/* if someone else already owns the broadcast, we won't take it */
+	if (arc_bcast_proto == arc_proto_default)
+		arc_bcast_proto = &rfc1201_proto;
+}
+
+
+#ifdef MODULE
+
+int __init init_module(void)
+{
+	printk(VERSION);
+	arcnet_rfc1201_init();
+	return 0;
+}
+
+void cleanup_module(void)
+{
+	arcnet_unregister_proto(&rfc1201_proto);
+}
+
+#endif				/* MODULE */
+
+
+/*
+ * Determine a packet's protocol ID.
+ * 
+ * With ARCnet we have to convert everything to Ethernet-style stuff.
+ */
+static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev)
+{
+	struct archdr *pkt = (struct archdr *) skb->data;
+	struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
+	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
+	int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
+
+	/* Pull off the arcnet header. */
+	skb->mac.raw = skb->data;
+	skb_pull(skb, hdr_size);
+
+	if (pkt->hard.dest == 0)
+		skb->pkt_type = PACKET_BROADCAST;
+	else if (dev->flags & IFF_PROMISC) {
+		/* if we're not sending to ourselves :) */
+		if (pkt->hard.dest != dev->dev_addr[0])
+			skb->pkt_type = PACKET_OTHERHOST;
+	}
+	/* now return the protocol number */
+	switch (soft->proto) {
+	case ARC_P_IP:
+		return htons(ETH_P_IP);
+	case ARC_P_ARP:
+		return htons(ETH_P_ARP);
+	case ARC_P_RARP:
+		return htons(ETH_P_RARP);
+
+	case ARC_P_IPX:
+	case ARC_P_NOVELL_EC:
+		return htons(ETH_P_802_3);
+	default:
+		lp->stats.rx_errors++;
+		lp->stats.rx_crc_errors++;
+		return 0;
+	}
+
+	return htons(ETH_P_IP);
+}
+
+
+/* packet receiver */
+static void rx(struct net_device *dev, int bufnum,
+	       struct archdr *pkthdr, int length)
+{
+	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
+	struct sk_buff *skb;
+	struct archdr *pkt = pkthdr;
+	struct arc_rfc1201 *soft = &pkthdr->soft.rfc1201;
+	int saddr = pkt->hard.source, ofs;
+	struct Incoming *in = &lp->rfc1201.incoming[saddr];
+
+	BUGMSG(D_DURING, "it's an RFC1201 packet (length=%d)\n", length);
+
+	if (length >= MinTU)
+		ofs = 512 - length;
+	else
+		ofs = 256 - length;
+
+	if (soft->split_flag == 0xFF) {		/* Exception Packet */
+		if (length >= 4 + RFC1201_HDR_SIZE)
+			BUGMSG(D_DURING, "compensating for exception packet\n");
+		else {
+			BUGMSG(D_EXTRA, "short RFC1201 exception packet from %02Xh",
+			       saddr);
+			return;
+		}
+
+		/* skip over 4-byte junkola */
+		length -= 4;
+		ofs += 4;
+		lp->hw.copy_from_card(dev, bufnum, 512 - length,
+				      soft, sizeof(pkt->soft));
+	}
+	if (!soft->split_flag) {	/* not split */
+		BUGMSG(D_RX, "incoming is not split (splitflag=%d)\n",
+		       soft->split_flag);
+
+		if (in->skb) {	/* already assembling one! */
+			BUGMSG(D_EXTRA, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
+			 in->sequence, soft->split_flag, soft->sequence);
+			lp->rfc1201.aborted_seq = soft->sequence;
+			kfree_skb(in->skb);
+			lp->stats.rx_errors++;
+			lp->stats.rx_missed_errors++;
+			in->skb = NULL;
+		}
+		in->sequence = soft->sequence;
+
+		skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
+		if (skb == NULL) {
+			BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
+			lp->stats.rx_dropped++;
+			return;
+		}
+		skb_put(skb, length + ARC_HDR_SIZE);
+		skb->dev = dev;
+
+		pkt = (struct archdr *) skb->data;
+		soft = &pkt->soft.rfc1201;
+
+		/* up to sizeof(pkt->soft) has already been copied from the card */
+		memcpy(pkt, pkthdr, sizeof(struct archdr));
+		if (length > sizeof(pkt->soft))
+			lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
+				       pkt->soft.raw + sizeof(pkt->soft),
+					      length - sizeof(pkt->soft));
+
+		/*
+		 * ARP packets have problems when sent from some DOS systems: the
+		 * source address is always 0!  So we take the hardware source addr
+		 * (which is impossible to fumble) and insert it ourselves.
+		 */
+		if (soft->proto == ARC_P_ARP) {
+			struct arphdr *arp = (struct arphdr *) soft->payload;
+
+			/* make sure addresses are the right length */
+			if (arp->ar_hln == 1 && arp->ar_pln == 4) {
+				uint8_t *cptr = (uint8_t *) arp + sizeof(struct arphdr);
+
+				if (!*cptr) {	/* is saddr = 00? */
+					BUGMSG(D_EXTRA,
+					       "ARP source address was 00h, set to %02Xh.\n",
+					       saddr);
+					lp->stats.rx_crc_errors++;
+					*cptr = saddr;
+				} else {
+					BUGMSG(D_DURING, "ARP source address (%Xh) is fine.\n",
+					       *cptr);
+				}
+			} else {
+				BUGMSG(D_NORMAL, "funny-shaped ARP packet. (%Xh, %Xh)\n",
+				       arp->ar_hln, arp->ar_pln);
+				lp->stats.rx_errors++;
+				lp->stats.rx_crc_errors++;
+			}
+		}
+		BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
+
+		skb->protocol = type_trans(skb, dev);
+		netif_rx(skb);
+	} else {		/* split packet */
+		/*
+		 * NOTE: MSDOS ARP packet correction should only need to apply to
+		 * unsplit packets, since ARP packets are so short.
+		 *
+		 * My interpretation of the RFC1201 document is that if a packet is
+		 * received out of order, the entire assembly process should be
+		 * aborted.
+		 *
+		 * The RFC also mentions "it is possible for successfully received
+		 * packets to be retransmitted." As of 0.40 all previously received
+		 * packets are allowed, not just the most recent one.
+		 *
+		 * We allow multiple assembly processes, one for each ARCnet card
+		 * possible on the network.  Seems rather like a waste of memory,
+		 * but there's no other way to be reliable.
+		 */
+
+		BUGMSG(D_RX, "packet is split (splitflag=%d, seq=%d)\n",
+		       soft->split_flag, in->sequence);
+
+		if (in->skb && in->sequence != soft->sequence) {
+			BUGMSG(D_EXTRA, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
+			       saddr, in->sequence, soft->sequence,
+			       soft->split_flag);
+			kfree_skb(in->skb);
+			in->skb = NULL;
+			lp->stats.rx_errors++;
+			lp->stats.rx_missed_errors++;
+			in->lastpacket = in->numpackets = 0;
+		}
+		if (soft->split_flag & 1) {	/* first packet in split */
+			BUGMSG(D_RX, "brand new splitpacket (splitflag=%d)\n",
+			       soft->split_flag);
+			if (in->skb) {	/* already assembling one! */
+				BUGMSG(D_EXTRA, "aborting previous (seq=%d) assembly "
+				       "(splitflag=%d, seq=%d)\n",
+				       in->sequence, soft->split_flag,
+				       soft->sequence);
+				lp->stats.rx_errors++;
+				lp->stats.rx_missed_errors++;
+				kfree_skb(in->skb);
+			}
+			in->sequence = soft->sequence;
+			in->numpackets = ((unsigned) soft->split_flag >> 1) + 2;
+			in->lastpacket = 1;
+
+			if (in->numpackets > 16) {
+				BUGMSG(D_EXTRA, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
+				       soft->split_flag);
+				lp->stats.rx_errors++;
+				lp->stats.rx_length_errors++;
+				return;
+			}
+			in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
+						  GFP_ATOMIC);
+			if (skb == NULL) {
+				BUGMSG(D_NORMAL, "(split) memory squeeze, dropping packet.\n");
+				lp->stats.rx_dropped++;
+				return;
+			}
+			skb->dev = dev;
+			pkt = (struct archdr *) skb->data;
+			soft = &pkt->soft.rfc1201;
+
+			memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
+			skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
+
+			soft->split_flag = 0;	/* end result won't be split */
+		} else {	/* not first packet */
+			int packetnum = ((unsigned) soft->split_flag >> 1) + 1;
+
+			/*
+			 * if we're not assembling, there's no point trying to
+			 * continue.
+			 */
+			if (!in->skb) {
+				if (lp->rfc1201.aborted_seq != soft->sequence) {
+					BUGMSG(D_EXTRA, "can't continue split without starting "
+					       "first! (splitflag=%d, seq=%d, aborted=%d)\n",
+					soft->split_flag, soft->sequence,
+					       lp->rfc1201.aborted_seq);
+					lp->stats.rx_errors++;
+					lp->stats.rx_missed_errors++;
+				}
+				return;
+			}
+			in->lastpacket++;
+			if (packetnum != in->lastpacket) {	/* not the right flag! */
+				/* harmless duplicate? ignore. */
+				if (packetnum <= in->lastpacket - 1) {
+					BUGMSG(D_EXTRA, "duplicate splitpacket ignored! (splitflag=%d)\n",
+					       soft->split_flag);
+					lp->stats.rx_errors++;
+					lp->stats.rx_frame_errors++;
+					return;
+				}
+				/* "bad" duplicate, kill reassembly */
+				BUGMSG(D_EXTRA, "out-of-order splitpacket, reassembly "
+				       "(seq=%d) aborted (splitflag=%d, seq=%d)\n",
+				       in->sequence, soft->split_flag, soft->sequence);
+				lp->rfc1201.aborted_seq = soft->sequence;
+				kfree_skb(in->skb);
+				in->skb = NULL;
+				lp->stats.rx_errors++;
+				lp->stats.rx_missed_errors++;
+				in->lastpacket = in->numpackets = 0;
+				return;
+			}
+			pkt = (struct archdr *) in->skb->data;
+			soft = &pkt->soft.rfc1201;
+		}
+
+		skb = in->skb;
+
+		lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
+				      skb->data + skb->len,
+				      length - RFC1201_HDR_SIZE);
+		skb_put(skb, length - RFC1201_HDR_SIZE);
+
+		/* are we done? */
+		if (in->lastpacket == in->numpackets) {
+			in->skb = NULL;
+			in->lastpacket = in->numpackets = 0;
+
+			BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
+
+			skb->protocol = type_trans(skb, dev);
+			netif_rx(skb);
+		}
+	}
+}
+
+
+/* Create the ARCnet hard/soft headers for RFC1201. */
+static int build_header(struct sk_buff *skb, unsigned short type,
+			uint8_t daddr)
+{
+	struct net_device *dev = skb->dev;
+	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
+	int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
+	struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
+	struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
+
+	/* set the protocol ID according to RFC1201 */
+	switch (type) {
+	case ETH_P_IP:
+		soft->proto = ARC_P_IP;
+		break;
+	case ETH_P_ARP:
+		soft->proto = ARC_P_ARP;
+		break;
+	case ETH_P_RARP:
+		soft->proto = ARC_P_RARP;
+		break;
+	case ETH_P_IPX:
+	case ETH_P_802_3:
+	case ETH_P_802_2:
+		soft->proto = ARC_P_IPX;
+		break;
+	case ETH_P_ATALK:
+		soft->proto = ARC_P_ATALK;
+		break;
+	default:
+		BUGMSG(D_NORMAL, "RFC1201: I don't understand protocol %d (%Xh)\n",
+		       type, type);
+		lp->stats.tx_errors++;
+		lp->stats.tx_aborted_errors++;
+		return 0;
+	}
+
+	/*
+	 * Set the source hardware address.
+	 *
+	 * This is pretty pointless for most purposes, but it can help in
+	 * debugging.  ARCnet does not allow us to change the source address in
+	 * the actual packet sent)
+	 */
+	pkt->hard.source = *dev->dev_addr;
+
+	soft->sequence = htons(lp->rfc1201.sequence++);
+	soft->split_flag = 0;	/* split packets are done elsewhere */
+
+	/* see linux/net/ethernet/eth.c to see where I got the following */
+
+	if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
+		/* 
+		 * FIXME: fill in the last byte of the dest ipaddr here to better
+		 * comply with RFC1051 in "noarp" mode.  For now, always broadcasting
+		 * will probably at least get packets sent out :)
+		 */
+		pkt->hard.dest = 0;
+		return hdr_size;
+	}
+	/* otherwise, drop in the dest address */
+	pkt->hard.dest = daddr;
+	return hdr_size;
+}
+
+
+static void load_pkt(struct net_device *dev, struct arc_hardware *hard,
+		     struct arc_rfc1201 *soft, int softlen, int bufnum)
+{
+	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
+	int ofs;
+
+	/* assume length <= XMTU: someone should have handled that by now. */
+
+	if (softlen > MinTU) {
+		hard->offset[0] = 0;
+		hard->offset[1] = ofs = 512 - softlen;
+	} else if (softlen > MTU) {	/* exception packet - add an extra header */
+		struct arc_rfc1201 excsoft =
+		{soft->proto, 0xFF, 0xFFFF};
+
+		hard->offset[0] = 0;
+		ofs = 512 - softlen;
+		hard->offset[1] = ofs - RFC1201_HDR_SIZE;
+		lp->hw.copy_to_card(dev, bufnum, ofs - RFC1201_HDR_SIZE,
+				    &excsoft, RFC1201_HDR_SIZE);
+	} else
+		hard->offset[0] = ofs = 256 - softlen;
+
+	lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
+	lp->hw.copy_to_card(dev, bufnum, ofs, soft, softlen);
+
+	lp->lastload_dest = hard->dest;
+}
+
+
+static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
+		      int bufnum)
+{
+	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
+	const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
+	struct Outgoing *out;
+
+
+	BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
+	       lp->next_tx, lp->cur_tx, bufnum);
+
+	length -= ARC_HDR_SIZE;	/* hard header is not included in packet length */
+	pkt->soft.rfc1201.split_flag = 0;
+
+	/* need to do a split packet? */
+	if (length > XMTU) {
+		out = &lp->outgoing;
+
+		out->length = length - RFC1201_HDR_SIZE;
+		out->dataleft = lp->outgoing.length;
+		out->numsegs = (out->dataleft + maxsegsize - 1) / maxsegsize;
+		out->segnum = 0;
+
+		BUGMSG(D_DURING, "rfc1201 prep_tx: ready for %d-segment split "
+		       "(%d bytes, seq=%d)\n", out->numsegs, out->length,
+		       pkt->soft.rfc1201.sequence);
+
+		return 0;	/* not done */
+	}
+	/* just load the packet into the buffers and send it off */
+	load_pkt(dev, &pkt->hard, &pkt->soft.rfc1201, length, bufnum);
+
+	return 1;		/* done */
+}
+
+
+static int continue_tx(struct net_device *dev, int bufnum)
+{
+	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
+	struct Outgoing *out = &lp->outgoing;
+	struct arc_hardware *hard = &out->pkt->hard;
+	struct arc_rfc1201 *soft = &out->pkt->soft.rfc1201, *newsoft;
+	int maxsegsize = XMTU - RFC1201_HDR_SIZE;
+	int seglen;
+
+	BUGMSG(D_DURING,
+	  "rfc1201 continue_tx: loading segment %d(+1) of %d (seq=%d)\n",
+	       out->segnum, out->numsegs, soft->sequence);
+
+	/* the "new" soft header comes right before the data chunk */
+	newsoft = (struct arc_rfc1201 *)
+	    (out->pkt->soft.raw + out->length - out->dataleft);
+
+	if (!out->segnum)	/* first packet; newsoft == soft */
+		newsoft->split_flag = ((out->numsegs - 2) << 1) | 1;
+	else {
+		newsoft->split_flag = out->segnum << 1;
+		newsoft->proto = soft->proto;
+		newsoft->sequence = soft->sequence;
+	}
+
+	seglen = maxsegsize;
+	if (seglen > out->dataleft)
+		seglen = out->dataleft;
+	out->dataleft -= seglen;
+
+	load_pkt(dev, hard, newsoft, seglen + RFC1201_HDR_SIZE, bufnum);
+
+	out->segnum++;
+	if (out->segnum >= out->numsegs)
+		return 1;
+	else
+		return 0;
+}