patch-2.3.4 linux/net/decnet/dn_nsp_in.c

• Lines: 704
• Date: Sat May 29 11:09:54 1999
• Orig file: v2.3.3/linux/net/decnet/dn_nsp_in.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.3/linux/net/decnet/dn_nsp_in.c linux/net/decnet/dn_nsp_in.c
@@ -0,0 +1,703 @@
+
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Network Services Protocol (Input)
+ *
+ * Author:      Eduardo Marcelo Serrat <emserrat@geocities.com>
+ *
+ * Changes:
+ *
+ *    Steve Whitehouse:  Split into dn_nsp_in.c and dn_nsp_out.c from
+ *                       original dn_nsp.c.
+ *    Steve Whitehouse:  Updated to work with my new routing architecture.
+ *    Steve Whitehouse:  Add changes from Eduardo Serrat's patches.
+ *    Steve Whitehouse:  Put all ack handling code in a common routine.
+ *    Steve Whitehouse:  Put other common bits into dn_nsp_rx()
+ *    Steve Whitehouse:  More checks on skb->len to catch bogus packets
+ *                       Fixed various race conditions and possible nasties.
+ *    Steve Whitehouse:  Now handles returned conninit frames.
+ */
+
+/******************************************************************************
+    (c) 1995-1998 E.M. Serrat		emserrat@geocities.com
+    
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+*******************************************************************************/
+
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/inet.h>
+#include <linux/route.h>
+#include <net/sock.h>
+#include <asm/segment.h>
+#include <asm/system.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/termios.h>      
+#include <linux/interrupt.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/dn_nsp.h>
+#include <net/dn_dev.h>
+#include <net/dn_route.h>
+#include <net/dn_raw.h>
+
+
+/*
+ * For this function we've flipped the cross-subchannel bit
+ * if the message is an otherdata or linkservice message. Thus
+ * we can use it to work out what to update.
+ */
+static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
+{
+	struct dn_scp *scp = &sk->protinfo.dn;
+	unsigned short type = ((ack >> 12) & 0x0003);
+	int wakeup = 0;
+
+	/* printk(KERN_DEBUG "dn_ack: %hd 0x%04hx\n", type, ack); */
+
+	switch(type) {
+		case 0: /* ACK - Data */
+			if (after(ack, scp->ackrcv_dat)) {
+				scp->ackrcv_dat = ack & 0x0fff;
+				wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->data_xmit_queue, ack);
+			}
+			break;
+		case 1: /* NAK - Data */
+			break;
+		case 2: /* ACK - OtherData */
+			if (after(ack, scp->ackrcv_oth)) {
+				scp->ackrcv_oth = ack & 0x0fff;
+				wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->other_xmit_queue, ack);
+			}
+			break;
+		case 3: /* NAK - OtherData */
+			break;
+	}
+
+	if (wakeup && !sk->dead)
+		sk->state_change(sk);
+}
+
+/*
+ * This function is a universal ack processor.
+ */
+static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
+{
+	unsigned short *ptr = (unsigned short *)skb->data;
+	int len = 0;
+	unsigned short ack;
+
+	if (skb->len < 2)
+		return len;
+
+	if ((ack = dn_ntohs(*ptr)) & 0x8000) {
+		skb_pull(skb, 2);
+		ptr++;
+		len += 2;
+		if ((ack & 0x4000) == 0) {
+			if (oth) 
+				ack ^= 0x2000;
+			dn_ack(sk, skb, ack);
+		}
+	}
+
+	if (skb->len < 2)
+		return len;
+
+	if ((ack = dn_ntohs(*ptr)) & 0x8000) {
+		skb_pull(skb, 2);
+		len += 2;
+		if ((ack & 0x4000) == 0) {
+			if (oth) 
+				ack ^= 0x2000;
+			dn_ack(sk, skb, ack);
+		}
+	}
+
+	return len;
+}
+
+
+/*
+ * This function uses a slightly different lookup method
+ * to find its sockets, since it searches on object name/number
+ * rather than port numbers
+ */
+static int dn_conninit_rx(struct sk_buff *skb)
+{
+	struct sock *sk;
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
+	struct sockaddr_dn addr;
+	unsigned char type = 0;
+
+	memset(&addr, 0, sizeof(struct sockaddr_dn));
+
+	cb->src_port = msg->srcaddr;
+	cb->dst_port = msg->dstaddr;
+	cb->services = msg->services;
+	cb->info     = msg->info;
+	cb->segsize  = dn_ntohs(msg->segsize);
+
+	skb_pull(skb, sizeof(*msg));
+
+	/* printk(KERN_DEBUG "username2sockaddr 1\n"); */
+	if (dn_username2sockaddr(skb->data, skb->len, &addr, &type) < 0)
+		goto free_out;
+
+	if (type > 1)
+		goto free_out;
+
+	/* printk(KERN_DEBUG "looking for listener...\n"); */
+	if ((sk = dn_sklist_find_listener(&addr)) == NULL)
+		return 1;
+
+	/* printk(KERN_DEBUG "checking backlog...\n"); */
+	if (sk->ack_backlog >= sk->max_ack_backlog)
+		goto free_out;
+
+	/* printk(KERN_DEBUG "waking up socket...\n"); */
+	sk->ack_backlog++;
+	skb_queue_tail(&sk->receive_queue, skb);
+	sk->state_change(sk);
+
+	return 0;
+
+free_out:
+	kfree_skb(skb);
+	return 0;
+}
+
+static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	struct dn_scp *scp = &sk->protinfo.dn;
+
+	if (skb->len < 3)
+		goto out;
+
+	cb->services = *skb->data;
+	cb->info = *(skb->data+1);
+	skb_pull(skb, 2);
+	cb->segsize = dn_ntohs(*(__u16 *)skb->data);
+	skb_pull(skb, 2);
+
+	/*
+	 * FIXME: Check out services and info fields to check that
+	 * we can talk to this kind of node.
+	 */
+
+	if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
+		scp->persist = 0;
+                scp->addrrem = cb->src_port;
+                sk->state = TCP_ESTABLISHED;
+                scp->state = DN_RUN;
+
+		if (scp->mss > cb->segsize)
+			scp->mss = cb->segsize;
+		if (scp->mss < 230)
+			scp->mss = 230;
+
+		if (skb->len > 0) {
+			unsigned char dlen = *skb->data;
+			if ((dlen <= 16) && (dlen <= skb->len)) {
+				scp->conndata_in.opt_optl = dlen;
+				memcpy(scp->conndata_in.opt_data, skb->data + 1, dlen);
+			}
+		}
+                dn_nsp_send_lnk(sk, DN_NOCHANGE);
+                if (!sk->dead)
+                	sk->state_change(sk);
+        }
+
+out:
+        kfree_skb(skb);
+}
+
+static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = &sk->protinfo.dn;
+
+	if (scp->state == DN_CI) {
+		scp->state = DN_CD;
+		scp->persist = 0;
+	}
+
+	kfree_skb(skb);
+}
+
+static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = &sk->protinfo.dn;
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	unsigned short reason;
+
+	/* printk(KERN_DEBUG "DECnet: discinit %d\n", skb->len); */
+
+	if (skb->len < 2)
+		goto out;
+
+	reason = dn_ntohs(*(__u16 *)skb->data);
+	skb_pull(skb, 2);
+
+	scp->discdata_in.opt_status = reason;
+	scp->discdata_in.opt_optl   = 0;
+	memset(scp->discdata_in.opt_data, 0, 16);
+
+	if (skb->len > 0) {
+		unsigned char dlen = *skb->data;
+		if ((dlen <= 16) && (dlen <= skb->len)) {
+			scp->discdata_in.opt_optl = dlen;
+			memcpy(scp->discdata_in.opt_data, skb->data + 1, dlen);
+		}
+	}
+
+	scp->addrrem = cb->src_port;
+	sk->state    = TCP_CLOSE;
+
+	/* printk(KERN_DEBUG "DECnet: discinit\n"); */
+
+	switch(scp->state) {
+		case DN_CI:
+		case DN_CD:
+			scp->state = DN_RJ;
+			break;
+		case DN_RUN:
+			sk->shutdown |= SHUTDOWN_MASK;
+			scp->state = DN_DN;
+			break;
+		case DN_DI:
+			scp->state = DN_DIC;
+			break;
+	}
+
+	if (!sk->dead)
+		sk->state_change(sk);
+
+	dn_destroy_sock(sk);
+
+out:
+	kfree_skb(skb);
+}
+
+/*
+ * disc_conf messages are also called no_resources or no_link
+ * messages depending upon the "reason" field.
+ */
+static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = &sk->protinfo.dn;
+	unsigned short reason;
+
+	if (skb->len != 2)
+		goto out;
+
+	reason = dn_ntohs(*(__u16 *)skb->data);
+
+	sk->state = TCP_CLOSE;
+
+	switch(scp->state) {
+		case DN_CI:
+			scp->state = DN_NR;
+			break;
+		case DN_DR:
+			if (reason == NSP_REASON_DC)
+				scp->state = DN_DRC;
+			if (reason == NSP_REASON_NL)
+				scp->state = DN_CN;
+			break;
+		case DN_DI:
+			scp->state = DN_DIC;
+			break;
+		case DN_RUN:
+			sk->shutdown |= SHUTDOWN_MASK;
+		case DN_CC:
+			scp->state = DN_CN;
+	}
+
+	if (!sk->dead)
+		sk->state_change(sk);
+
+	dn_destroy_sock(sk);
+
+out:
+	kfree_skb(skb);
+}
+
+static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	unsigned short segnum;
+	unsigned char lsflags;
+	char fcval;
+
+	if (skb->len != 4)
+		goto out;
+
+	cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
+	skb_pull(skb, 2);
+	lsflags = *(unsigned char *)skb->data;
+	skb_pull(skb, 1);
+	fcval = *(char *)skb->data;
+
+	if (lsflags & 0xf0)
+		goto out;
+
+	if (((sk->protinfo.dn.numoth_rcv + 1) & 0x0FFF) == (segnum & 0x0FFF)) {
+        	sk->protinfo.dn.numoth_rcv += 1;        
+                switch(lsflags & 0x03) {
+                	case 0x00:      
+                        	break;
+                        case 0x01:      
+                                sk->protinfo.dn.flowrem_sw = DN_DONTSEND;
+                                break;
+                        case 0x02:      
+                                sk->protinfo.dn.flowrem_sw = DN_SEND;
+				dn_nsp_output(sk);
+				if (!sk->dead)
+					sk->state_change(sk);
+                }
+                
+        }
+
+	dn_nsp_send_oth_ack(sk);
+
+out:
+	kfree_skb(skb);
+}
+
+/*
+ * Copy of sock_queue_rcv_skb (from net/core/datagram.c) to
+ * queue other data segments. Also we send SIGURG here instead
+ * of the normal SIGIO, 'cos its out of band data.
+ */
+static __inline__ int dn_queue_other_skb(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = &sk->protinfo.dn;
+
+        /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
+           number of warnings when compiling with -W --ANK
+         */
+        if (atomic_read(&sk->rmem_alloc) + skb->truesize >= (unsigned)sk->rcvbuf
+)
+                return -ENOMEM;
+
+#ifdef CONFIG_FILTER
+        if (sk->filter)
+        {
+                if (sk_filter(skb, sk->filter))
+                        return -EPERM;  /* Toss packet */
+        }
+#endif /* CONFIG_FILTER */
+
+        skb_set_owner_r(skb, sk);
+        skb_queue_tail(&scp->other_receive_queue, skb);
+
+        if (!sk->dead) {
+		struct socket *sock = sk->socket;
+		wake_up_interruptible(sk->sleep);
+		if (!(sock->flags & SO_WAITDATA) && sock->fasync_list)
+			kill_fasync(sock->fasync_list, SIGURG);
+	}
+
+        return 0;
+}
+
+static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = &sk->protinfo.dn;
+	unsigned short segnum;
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	int queued = 0;
+
+	if (skb->len < 2)
+		goto out;
+
+	cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
+	skb_pull(skb, 2);
+
+	if (((sk->protinfo.dn.numoth_rcv + 1) & 0x0fff) == (segnum & 0x0fff)) {
+
+		if (dn_queue_other_skb(sk, skb) == 0) {
+			sk->protinfo.dn.numoth_rcv++;
+			scp->other_report = 0;
+			queued = 1;
+		}
+	}
+
+	dn_nsp_send_oth_ack(sk);
+out:
+	if (!queued)
+		kfree_skb(skb);
+}
+
+static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
+{
+	int queued = 0;
+	unsigned short segnum;
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	struct dn_scp *scp = &sk->protinfo.dn;
+
+	if (skb->len < 2)
+		goto out;
+
+	cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
+	skb_pull(skb, 2);
+
+	if (((sk->protinfo.dn.numdat_rcv + 1) & 0x0FFF) == 
+                     (segnum & 0x0FFF)) {
+
+                if (sock_queue_rcv_skb(sk, skb) == 0) {
+			sk->protinfo.dn.numdat_rcv++;
+                	queued = 1;
+                }
+
+		if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
+			scp->flowloc_sw = DN_DONTSEND;
+			dn_nsp_send_lnk(sk, DN_DONTSEND);
+		}
+        }
+
+	dn_nsp_send_data_ack(sk);
+out:
+	if (!queued)
+		kfree_skb(skb);
+}
+
+/*
+ * If one of our conninit messages is returned, this function
+ * deals with it. It puts the socket into the NO_COMMUNICATION
+ * state.
+ */
+static void dn_returned_conninit(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	struct sock *sk;
+
+	cb->dst_port = cb->src_port;
+	cb->src_port = 0;
+
+	if ((sk = dn_find_by_skb(skb)) != NULL) {
+		struct dn_scp *scp = &sk->protinfo.dn;
+		if (scp->state == DN_CI) {
+			scp->state = DN_NC;
+			sk->state = TCP_CLOSE;
+			if (!sk->dead)
+				sk->state_change(sk);
+		}
+	}
+
+	kfree_skb(skb);
+}
+
+int dn_nsp_rx(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	struct sock *sk = NULL;
+	unsigned char *ptr = (unsigned char *)skb->data;
+
+	skb->h.raw    = skb->data;
+	cb->nsp_flags = *ptr++;
+
+	if (decnet_debug_level & 1)
+		printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);
+
+#ifdef CONFIG_DECNET_RAW
+	dn_raw_rx_nsp(skb);
+#endif /* CONFIG_DECNET_RAW */
+
+	if (skb->len < 2) 
+		goto free_out;
+
+	if (cb->nsp_flags & 0x83) 
+		goto free_out;
+
+	/*
+	 * Returned packets...
+	 */
+	if (cb->rt_flags & DN_RT_F_RTS) {
+		if ((cb->nsp_flags & 0x0c) == 0x08) {
+			switch(cb->nsp_flags & 0x70) {
+				case 0x10:
+				case 0x60:
+					dn_returned_conninit(skb);
+					goto out;
+			}
+		}
+		goto free_out;
+	}
+
+	/*
+	 * Filter out conninits and useless packet types
+	 */
+	if ((cb->nsp_flags & 0x0c) == 0x08) {
+		switch(cb->nsp_flags & 0x70) {
+			case 0x00: /* NOP */
+			case 0x70: /* Reserved */
+			case 0x50: /* Reserved, Phase II node init */
+				goto free_out;
+			case 0x10:
+			case 0x60:
+				return dn_conninit_rx(skb);
+		}
+	}
+
+	if (skb->len < 3)
+		goto free_out;
+
+	/*
+	 * Grab the destination address.
+	 */
+	cb->dst_port = *(unsigned short *)ptr;
+	cb->src_port = 0;
+	ptr += 2;
+
+	/*
+	 * If not a connack, grab the source address too.
+	 */
+	if (skb->len >= 5) {
+		cb->src_port = *(unsigned short *)ptr;
+		ptr += 2;
+		skb_pull(skb, 5);
+	}
+
+	/*
+	 * Find the socket to which this skb is destined.
+	 */
+	if ((sk = dn_find_by_skb(skb)) != NULL) {
+		struct dn_scp *scp = &sk->protinfo.dn;
+		int ret;
+		/* printk(KERN_DEBUG "dn_nsp_rx: Found a socket\n"); */
+
+		/* Reset backoff */
+		scp->nsp_rxtshift = 0;
+
+		bh_lock_sock(sk);
+		ret = 0;
+		if (sk->lock.users == 0)
+			ret = dn_nsp_backlog_rcv(sk, skb);
+		else
+			sk_add_backlog(sk, skb);
+		bh_unlock_sock(sk);
+
+		return ret;
+	}
+	return 1;
+
+free_out:
+	kfree_skb(skb);
+out:
+	return 0;
+}
+
+/*
+ * This is the main receive routine for sockets. It is called
+ * from the above when the socket is not busy, and also from
+ * sock_release() when there is a backlog queued up.
+ */
+int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = &sk->protinfo.dn;
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+
+	/*
+	 * Control packet.
+	 */
+	if ((cb->nsp_flags & 0x0c) == 0x08) {
+		/* printk(KERN_DEBUG "control type\n"); */
+		switch(cb->nsp_flags & 0x70) {
+			case 0x20:
+				dn_nsp_conn_conf(sk, skb);
+				break;
+			case 0x30:
+				dn_nsp_disc_init(sk, skb);
+				break;
+			case 0x40:      
+				dn_nsp_disc_conf(sk, skb);
+				break;
+		}
+
+	} else if (cb->nsp_flags == 0x24) {
+		/*
+		 * Special for connacks, 'cos they don't have
+		 * ack data or ack otherdata info.
+		 */
+		dn_nsp_conn_ack(sk, skb);
+	} else {
+		int other = 1;
+
+		if ((cb->nsp_flags & 0x1c) == 0)
+			other = 0;
+		if (cb->nsp_flags == 0x04)
+			other = 0;
+
+		/*
+		 * Read out ack data here, this applies equally
+		 * to data, other data, link serivce and both
+		 * ack data and ack otherdata.
+		 */
+		dn_process_ack(sk, skb, other);
+
+		/*
+		 * If we've some sort of data here then call a
+		 * suitable routine for dealing with it, otherwise
+		 * the packet is an ack and can be discarded. All
+		 * data frames can also kick a CC socket into RUN.
+		 */
+		if ((cb->nsp_flags & 0x0c) == 0) {
+
+			if ((scp->state == DN_CC) && !sk->dead) {
+				scp->state = DN_RUN;
+				sk->state = TCP_ESTABLISHED;
+				sk->state_change(sk);
+			}
+
+			if (scp->state != DN_RUN)
+				goto free_out;
+
+			switch(cb->nsp_flags) {
+				case 0x10: /* LS */
+					dn_nsp_linkservice(sk, skb);
+					break;
+				case 0x30: /* OD */
+					dn_nsp_otherdata(sk, skb);
+					break;
+				default:
+					dn_nsp_data(sk, skb);
+			}
+
+		} else { /* Ack, chuck it out here */
+free_out:
+			kfree_skb(skb);
+		}
+	}
+
+	return 0;
+}
+