Remove DECnet support from kernel

DECnet is an obsolete network protocol that receives more attention
from kernel janitors than users. It belongs in computer protocol
history museum not in Linux kernel.

It has been "Orphaned" in kernel since 2010. The iproute2 support
for DECnet was dropped in 5.0 release. The documentation link on
Sourceforge says it is abandoned there as well.

Leave the UAPI alone to keep userspace programs compiling.
This means that there is still an empty neighbour table
for AF_DECNET.

The table of /proc/sys/net entries was updated to match
current directories and reformatted to be alphabetical.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: David Ahern <dsahern@kernel.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 607 deletions

diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
deleted file mode 100644
index 7c569bcc0aca..000000000000
--- a/net/decnet/dn_neigh.c
+++ /dev/null
@@ -1,607 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * 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 Neighbour Functions (Adjacency Database and
- *                                                        On-Ethernet Cache)
- *
- * Author:      Steve Whitehouse <SteveW@ACM.org>
- *
- *
- * Changes:
- *     Steve Whitehouse     : Fixed router listing routine
- *     Steve Whitehouse     : Added error_report functions
- *     Steve Whitehouse     : Added default router detection
- *     Steve Whitehouse     : Hop counts in outgoing messages
- *     Steve Whitehouse     : Fixed src/dst in outgoing messages so
- *                            forwarding now stands a good chance of
- *                            working.
- *     Steve Whitehouse     : Fixed neighbour states (for now anyway).
- *     Steve Whitehouse     : Made error_report functions dummies. This
- *                            is not the right place to return skbs.
- *     Steve Whitehouse     : Convert to seq_file
- *
- */
-
-#include <linux/net.h>
-#include <linux/module.h>
-#include <linux/socket.h>
-#include <linux/if_arp.h>
-#include <linux/slab.h>
-#include <linux/if_ether.h>
-#include <linux/init.h>
-#include <linux/proc_fs.h>
-#include <linux/string.h>
-#include <linux/netfilter_decnet.h>
-#include <linux/spinlock.h>
-#include <linux/seq_file.h>
-#include <linux/rcupdate.h>
-#include <linux/jhash.h>
-#include <linux/atomic.h>
-#include <net/net_namespace.h>
-#include <net/neighbour.h>
-#include <net/dst.h>
-#include <net/flow.h>
-#include <net/dn.h>
-#include <net/dn_dev.h>
-#include <net/dn_neigh.h>
-#include <net/dn_route.h>
-
-static int dn_neigh_construct(struct neighbour *);
-static void dn_neigh_error_report(struct neighbour *, struct sk_buff *);
-static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb);
-
-/*
- * Operations for adding the link layer header.
- */
-static const struct neigh_ops dn_neigh_ops = {
-	.family =		AF_DECnet,
-	.error_report =		dn_neigh_error_report,
-	.output =		dn_neigh_output,
-	.connected_output =	dn_neigh_output,
-};
-
-static u32 dn_neigh_hash(const void *pkey,
-			 const struct net_device *dev,
-			 __u32 *hash_rnd)
-{
-	return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
-}
-
-static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)
-{
-	return neigh_key_eq16(neigh, pkey);
-}
-
-struct neigh_table dn_neigh_table = {
-	.family =			PF_DECnet,
-	.entry_size =			NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
-	.key_len =			sizeof(__le16),
-	.protocol =			cpu_to_be16(ETH_P_DNA_RT),
-	.hash =				dn_neigh_hash,
-	.key_eq =			dn_key_eq,
-	.constructor =			dn_neigh_construct,
-	.id =				"dn_neigh_cache",
-	.parms ={
-		.tbl =			&dn_neigh_table,
-		.reachable_time =	30 * HZ,
-		.data = {
-			[NEIGH_VAR_MCAST_PROBES] = 0,
-			[NEIGH_VAR_UCAST_PROBES] = 0,
-			[NEIGH_VAR_APP_PROBES] = 0,
-			[NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
-			[NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
-			[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
-			[NEIGH_VAR_INTERVAL_PROBE_TIME_MS] = 5 * HZ,
-			[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
-			[NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
-			[NEIGH_VAR_PROXY_QLEN] = 0,
-			[NEIGH_VAR_ANYCAST_DELAY] = 0,
-			[NEIGH_VAR_PROXY_DELAY] = 0,
-			[NEIGH_VAR_LOCKTIME] = 1 * HZ,
-		},
-	},
-	.gc_interval =			30 * HZ,
-	.gc_thresh1 =			128,
-	.gc_thresh2 =			512,
-	.gc_thresh3 =			1024,
-};
-
-static int dn_neigh_construct(struct neighbour *neigh)
-{
-	struct net_device *dev = neigh->dev;
-	struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
-	struct dn_dev *dn_db;
-	struct neigh_parms *parms;
-
-	rcu_read_lock();
-	dn_db = rcu_dereference(dev->dn_ptr);
-	if (dn_db == NULL) {
-		rcu_read_unlock();
-		return -EINVAL;
-	}
-
-	parms = dn_db->neigh_parms;
-	if (!parms) {
-		rcu_read_unlock();
-		return -EINVAL;
-	}
-
-	__neigh_parms_put(neigh->parms);
-	neigh->parms = neigh_parms_clone(parms);
-	rcu_read_unlock();
-
-	neigh->ops = &dn_neigh_ops;
-	neigh->nud_state = NUD_NOARP;
-	neigh->output = neigh->ops->connected_output;
-
-	if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
-		memcpy(neigh->ha, dev->broadcast, dev->addr_len);
-	else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
-		dn_dn2eth(neigh->ha, dn->addr);
-	else {
-		net_dbg_ratelimited("Trying to create neigh for hw %d\n",
-				    dev->type);
-		return -EINVAL;
-	}
-
-	/*
-	 * Make an estimate of the remote block size by assuming that its
-	 * two less then the device mtu, which it true for ethernet (and
-	 * other things which support long format headers) since there is
-	 * an extra length field (of 16 bits) which isn't part of the
-	 * ethernet headers and which the DECnet specs won't admit is part
-	 * of the DECnet routing headers either.
-	 *
-	 * If we over estimate here its no big deal, the NSP negotiations
-	 * will prevent us from sending packets which are too large for the
-	 * remote node to handle. In any case this figure is normally updated
-	 * by a hello message in most cases.
-	 */
-	dn->blksize = dev->mtu - 2;
-
-	return 0;
-}
-
-static void dn_neigh_error_report(struct neighbour *neigh, struct sk_buff *skb)
-{
-	printk(KERN_DEBUG "dn_neigh_error_report: called\n");
-	kfree_skb(skb);
-}
-
-static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb)
-{
-	struct dst_entry *dst = skb_dst(skb);
-	struct dn_route *rt = (struct dn_route *)dst;
-	struct net_device *dev = neigh->dev;
-	char mac_addr[ETH_ALEN];
-	unsigned int seq;
-	int err;
-
-	dn_dn2eth(mac_addr, rt->rt_local_src);
-	do {
-		seq = read_seqbegin(&neigh->ha_lock);
-		err = dev_hard_header(skb, dev, ntohs(skb->protocol),
-				      neigh->ha, mac_addr, skb->len);
-	} while (read_seqretry(&neigh->ha_lock, seq));
-
-	if (err >= 0)
-		err = dev_queue_xmit(skb);
-	else {
-		kfree_skb(skb);
-		err = -EINVAL;
-	}
-	return err;
-}
-
-static int dn_neigh_output_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
-{
-	struct dst_entry *dst = skb_dst(skb);
-	struct dn_route *rt = (struct dn_route *)dst;
-	struct neighbour *neigh = rt->n;
-
-	return neigh->output(neigh, skb);
-}
-
-/*
- * For talking to broadcast devices: Ethernet & PPP
- */
-static int dn_long_output(struct neighbour *neigh, struct sock *sk,
-			  struct sk_buff *skb)
-{
-	struct net_device *dev = neigh->dev;
-	int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
-	unsigned char *data;
-	struct dn_long_packet *lp;
-	struct dn_skb_cb *cb = DN_SKB_CB(skb);
-
-
-	if (skb_headroom(skb) < headroom) {
-		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
-		if (skb2 == NULL) {
-			net_crit_ratelimited("dn_long_output: no memory\n");
-			kfree_skb(skb);
-			return -ENOBUFS;
-		}
-		consume_skb(skb);
-		skb = skb2;
-		net_info_ratelimited("dn_long_output: Increasing headroom\n");
-	}
-
-	data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
-	lp = (struct dn_long_packet *)(data+3);
-
-	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
-	*(data + 2) = 1 | DN_RT_F_PF; /* Padding */
-
-	lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
-	lp->d_area   = lp->d_subarea = 0;
-	dn_dn2eth(lp->d_id, cb->dst);
-	lp->s_area   = lp->s_subarea = 0;
-	dn_dn2eth(lp->s_id, cb->src);
-	lp->nl2      = 0;
-	lp->visit_ct = cb->hops & 0x3f;
-	lp->s_class  = 0;
-	lp->pt       = 0;
-
-	skb_reset_network_header(skb);
-
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
-		       &init_net, sk, skb, NULL, neigh->dev,
-		       dn_neigh_output_packet);
-}
-
-/*
- * For talking to pointopoint and multidrop devices: DDCMP and X.25
- */
-static int dn_short_output(struct neighbour *neigh, struct sock *sk,
-			   struct sk_buff *skb)
-{
-	struct net_device *dev = neigh->dev;
-	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
-	struct dn_short_packet *sp;
-	unsigned char *data;
-	struct dn_skb_cb *cb = DN_SKB_CB(skb);
-
-
-	if (skb_headroom(skb) < headroom) {
-		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
-		if (skb2 == NULL) {
-			net_crit_ratelimited("dn_short_output: no memory\n");
-			kfree_skb(skb);
-			return -ENOBUFS;
-		}
-		consume_skb(skb);
-		skb = skb2;
-		net_info_ratelimited("dn_short_output: Increasing headroom\n");
-	}
-
-	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
-	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
-	sp = (struct dn_short_packet *)(data+2);
-
-	sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
-	sp->dstnode    = cb->dst;
-	sp->srcnode    = cb->src;
-	sp->forward    = cb->hops & 0x3f;
-
-	skb_reset_network_header(skb);
-
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
-		       &init_net, sk, skb, NULL, neigh->dev,
-		       dn_neigh_output_packet);
-}
-
-/*
- * For talking to DECnet phase III nodes
- * Phase 3 output is the same as short output, execpt that
- * it clears the area bits before transmission.
- */
-static int dn_phase3_output(struct neighbour *neigh, struct sock *sk,
-			    struct sk_buff *skb)
-{
-	struct net_device *dev = neigh->dev;
-	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
-	struct dn_short_packet *sp;
-	unsigned char *data;
-	struct dn_skb_cb *cb = DN_SKB_CB(skb);
-
-	if (skb_headroom(skb) < headroom) {
-		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
-		if (skb2 == NULL) {
-			net_crit_ratelimited("dn_phase3_output: no memory\n");
-			kfree_skb(skb);
-			return -ENOBUFS;
-		}
-		consume_skb(skb);
-		skb = skb2;
-		net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
-	}
-
-	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
-	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
-	sp = (struct dn_short_packet *)(data + 2);
-
-	sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
-	sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
-	sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
-	sp->forward  = cb->hops & 0x3f;
-
-	skb_reset_network_header(skb);
-
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
-		       &init_net, sk, skb, NULL, neigh->dev,
-		       dn_neigh_output_packet);
-}
-
-int dn_to_neigh_output(struct net *net, struct sock *sk, struct sk_buff *skb)
-{
-	struct dst_entry *dst = skb_dst(skb);
-	struct dn_route *rt = (struct dn_route *) dst;
-	struct neighbour *neigh = rt->n;
-	struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
-	struct dn_dev *dn_db;
-	bool use_long;
-
-	rcu_read_lock();
-	dn_db = rcu_dereference(neigh->dev->dn_ptr);
-	if (dn_db == NULL) {
-		rcu_read_unlock();
-		return -EINVAL;
-	}
-	use_long = dn_db->use_long;
-	rcu_read_unlock();
-
-	if (dn->flags & DN_NDFLAG_P3)
-		return dn_phase3_output(neigh, sk, skb);
-	if (use_long)
-		return dn_long_output(neigh, sk, skb);
-	else
-		return dn_short_output(neigh, sk, skb);
-}
-
-/*
- * Unfortunately, the neighbour code uses the device in its hash
- * function, so we don't get any advantage from it. This function
- * basically does a neigh_lookup(), but without comparing the device
- * field. This is required for the On-Ethernet cache
- */
-
-/*
- * Pointopoint link receives a hello message
- */
-void dn_neigh_pointopoint_hello(struct sk_buff *skb)
-{
-	kfree_skb(skb);
-}
-
-/*
- * Ethernet router hello message received
- */
-int dn_neigh_router_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
-{
-	struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
-
-	struct neighbour *neigh;
-	struct dn_neigh *dn;
-	struct dn_dev *dn_db;
-	__le16 src;
-
-	src = dn_eth2dn(msg->id);
-
-	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
-
-	dn = container_of(neigh, struct dn_neigh, n);
-
-	if (neigh) {
-		write_lock(&neigh->lock);
-
-		neigh->used = jiffies;
-		dn_db = rcu_dereference(neigh->dev->dn_ptr);
-
-		if (!(neigh->nud_state & NUD_PERMANENT)) {
-			neigh->updated = jiffies;
-
-			if (neigh->dev->type == ARPHRD_ETHER)
-				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
-
-			dn->blksize  = le16_to_cpu(msg->blksize);
-			dn->priority = msg->priority;
-
-			dn->flags &= ~DN_NDFLAG_P3;
-
-			switch (msg->iinfo & DN_RT_INFO_TYPE) {
-			case DN_RT_INFO_L1RT:
-				dn->flags &=~DN_NDFLAG_R2;
-				dn->flags |= DN_NDFLAG_R1;
-				break;
-			case DN_RT_INFO_L2RT:
-				dn->flags |= DN_NDFLAG_R2;
-			}
-		}
-
-		/* Only use routers in our area */
-		if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
-			if (!dn_db->router) {
-				dn_db->router = neigh_clone(neigh);
-			} else {
-				if (msg->priority > container_of(dn_db->router,
-								 struct dn_neigh, n)->priority)
-					neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
-			}
-		}
-		write_unlock(&neigh->lock);
-		neigh_release(neigh);
-	}
-
-	kfree_skb(skb);
-	return 0;
-}
-
-/*
- * Endnode hello message received
- */
-int dn_neigh_endnode_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
-{
-	struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
-	struct neighbour *neigh;
-	struct dn_neigh *dn;
-	__le16 src;
-
-	src = dn_eth2dn(msg->id);
-
-	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
-
-	dn = container_of(neigh, struct dn_neigh, n);
-
-	if (neigh) {
-		write_lock(&neigh->lock);
-
-		neigh->used = jiffies;
-
-		if (!(neigh->nud_state & NUD_PERMANENT)) {
-			neigh->updated = jiffies;
-
-			if (neigh->dev->type == ARPHRD_ETHER)
-				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
-			dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
-			dn->blksize  = le16_to_cpu(msg->blksize);
-			dn->priority = 0;
-		}
-
-		write_unlock(&neigh->lock);
-		neigh_release(neigh);
-	}
-
-	kfree_skb(skb);
-	return 0;
-}
-
-static char *dn_find_slot(char *base, int max, int priority)
-{
-	int i;
-	unsigned char *min = NULL;
-
-	base += 6; /* skip first id */
-
-	for(i = 0; i < max; i++) {
-		if (!min || (*base < *min))
-			min = base;
-		base += 7; /* find next priority */
-	}
-
-	if (!min)
-		return NULL;
-
-	return (*min < priority) ? (min - 6) : NULL;
-}
-
-struct elist_cb_state {
-	struct net_device *dev;
-	unsigned char *ptr;
-	unsigned char *rs;
-	int t, n;
-};
-
-static void neigh_elist_cb(struct neighbour *neigh, void *_info)
-{
-	struct elist_cb_state *s = _info;
-	struct dn_neigh *dn;
-
-	if (neigh->dev != s->dev)
-		return;
-
-	dn = container_of(neigh, struct dn_neigh, n);
-	if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
-		return;
-
-	if (s->t == s->n)
-		s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
-	else
-		s->t++;
-	if (s->rs == NULL)
-		return;
-
-	dn_dn2eth(s->rs, dn->addr);
-	s->rs += 6;
-	*(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
-	*(s->rs) |= dn->priority;
-	s->rs++;
-}
-
-int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
-{
-	struct elist_cb_state state;
-
-	state.dev = dev;
-	state.t = 0;
-	state.n = n;
-	state.ptr = ptr;
-	state.rs = ptr;
-
-	neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
-
-	return state.t;
-}
-
-
-#ifdef CONFIG_PROC_FS
-
-static inline void dn_neigh_format_entry(struct seq_file *seq,
-					 struct neighbour *n)
-{
-	struct dn_neigh *dn = container_of(n, struct dn_neigh, n);
-	char buf[DN_ASCBUF_LEN];
-
-	read_lock(&n->lock);
-	seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
-		   dn_addr2asc(le16_to_cpu(dn->addr), buf),
-		   (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
-		   (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
-		   (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
-		   dn->n.nud_state,
-		   refcount_read(&dn->n.refcnt),
-		   dn->blksize,
-		   (dn->n.dev) ? dn->n.dev->name : "?");
-	read_unlock(&n->lock);
-}
-
-static int dn_neigh_seq_show(struct seq_file *seq, void *v)
-{
-	if (v == SEQ_START_TOKEN) {
-		seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
-	} else {
-		dn_neigh_format_entry(seq, v);
-	}
-
-	return 0;
-}
-
-static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
-{
-	return neigh_seq_start(seq, pos, &dn_neigh_table,
-			       NEIGH_SEQ_NEIGH_ONLY);
-}
-
-static const struct seq_operations dn_neigh_seq_ops = {
-	.start = dn_neigh_seq_start,
-	.next  = neigh_seq_next,
-	.stop  = neigh_seq_stop,
-	.show  = dn_neigh_seq_show,
-};
-#endif
-
-void __init dn_neigh_init(void)
-{
-	neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
-	proc_create_net("decnet_neigh", 0444, init_net.proc_net,
-			&dn_neigh_seq_ops, sizeof(struct neigh_seq_state));
-}
-
-void __exit dn_neigh_cleanup(void)
-{
-	remove_proc_entry("decnet_neigh", init_net.proc_net);
-	neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
-}