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>

3 files changed, 0 insertions, 181 deletions

diff --git a/net/decnet/netfilter/Kconfig b/net/decnet/netfilter/Kconfig
deleted file mode 100644
index 14ec4ef95fab..000000000000
--- a/net/decnet/netfilter/Kconfig
+++ /dev/null
@@ -1,17 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-#
-# DECnet netfilter configuration
-#
-
-menu "DECnet: Netfilter Configuration"
-	depends on DECNET && NETFILTER
-	depends on NETFILTER_ADVANCED
-
-config DECNET_NF_GRABULATOR
-	tristate "Routing message grabulator (for userland routing daemon)"
-	help
-	  Enable this module if you want to use the userland DECnet routing
-	  daemon. You will also need to enable routing support for DECnet
-	  unless you just want to monitor routing messages from other nodes.
-
-endmenu
diff --git a/net/decnet/netfilter/Makefile b/net/decnet/netfilter/Makefile
deleted file mode 100644
index 429c84289d0f..000000000000
--- a/net/decnet/netfilter/Makefile
+++ /dev/null
@@ -1,6 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-#
-# Makefile for DECnet netfilter modules
-#
-
-obj-$(CONFIG_DECNET_NF_GRABULATOR) += dn_rtmsg.o
diff --git a/net/decnet/netfilter/dn_rtmsg.c b/net/decnet/netfilter/dn_rtmsg.c
deleted file mode 100644
index 26a9193df783..000000000000
--- a/net/decnet/netfilter/dn_rtmsg.c
+++ /dev/null
@@ -1,158 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * 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 Routing Message Grabulator
- *
- *              (C) 2000 ChyGwyn Limited  -  https://www.chygwyn.com/
- *
- * Author:      Steven Whitehouse <steve@chygwyn.com>
- */
-#include <linux/module.h>
-#include <linux/skbuff.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/netdevice.h>
-#include <linux/netfilter.h>
-#include <linux/spinlock.h>
-#include <net/netlink.h>
-#include <linux/netfilter_decnet.h>
-
-#include <net/sock.h>
-#include <net/flow.h>
-#include <net/dn.h>
-#include <net/dn_route.h>
-
-static struct sock *dnrmg = NULL;
-
-
-static struct sk_buff *dnrmg_build_message(struct sk_buff *rt_skb, int *errp)
-{
-	struct sk_buff *skb = NULL;
-	size_t size;
-	sk_buff_data_t old_tail;
-	struct nlmsghdr *nlh;
-	unsigned char *ptr;
-	struct nf_dn_rtmsg *rtm;
-
-	size = NLMSG_ALIGN(rt_skb->len) +
-	       NLMSG_ALIGN(sizeof(struct nf_dn_rtmsg));
-	skb = nlmsg_new(size, GFP_ATOMIC);
-	if (!skb) {
-		*errp = -ENOMEM;
-		return NULL;
-	}
-	old_tail = skb->tail;
-	nlh = nlmsg_put(skb, 0, 0, 0, size, 0);
-	if (!nlh) {
-		kfree_skb(skb);
-		*errp = -ENOMEM;
-		return NULL;
-	}
-	rtm = (struct nf_dn_rtmsg *)nlmsg_data(nlh);
-	rtm->nfdn_ifindex = rt_skb->dev->ifindex;
-	ptr = NFDN_RTMSG(rtm);
-	skb_copy_from_linear_data(rt_skb, ptr, rt_skb->len);
-	nlh->nlmsg_len = skb->tail - old_tail;
-	return skb;
-}
-
-static void dnrmg_send_peer(struct sk_buff *skb)
-{
-	struct sk_buff *skb2;
-	int status = 0;
-	int group = 0;
-	unsigned char flags = *skb->data;
-
-	switch (flags & DN_RT_CNTL_MSK) {
-	case DN_RT_PKT_L1RT:
-		group = DNRNG_NLGRP_L1;
-		break;
-	case DN_RT_PKT_L2RT:
-		group = DNRNG_NLGRP_L2;
-		break;
-	default:
-		return;
-	}
-
-	skb2 = dnrmg_build_message(skb, &status);
-	if (skb2 == NULL)
-		return;
-	NETLINK_CB(skb2).dst_group = group;
-	netlink_broadcast(dnrmg, skb2, 0, group, GFP_ATOMIC);
-}
-
-
-static unsigned int dnrmg_hook(void *priv,
-			struct sk_buff *skb,
-			const struct nf_hook_state *state)
-{
-	dnrmg_send_peer(skb);
-	return NF_ACCEPT;
-}
-
-
-#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err), NULL); return; } while (0)
-
-static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
-{
-	struct nlmsghdr *nlh = nlmsg_hdr(skb);
-
-	if (skb->len < sizeof(*nlh) ||
-	    nlh->nlmsg_len < sizeof(*nlh) ||
-	    skb->len < nlh->nlmsg_len)
-		return;
-
-	if (!netlink_capable(skb, CAP_NET_ADMIN))
-		RCV_SKB_FAIL(-EPERM);
-
-	/* Eventually we might send routing messages too */
-
-	RCV_SKB_FAIL(-EINVAL);
-}
-
-static const struct nf_hook_ops dnrmg_ops = {
-	.hook		= dnrmg_hook,
-	.pf		= NFPROTO_DECNET,
-	.hooknum	= NF_DN_ROUTE,
-	.priority	= NF_DN_PRI_DNRTMSG,
-};
-
-static int __init dn_rtmsg_init(void)
-{
-	int rv = 0;
-	struct netlink_kernel_cfg cfg = {
-		.groups	= DNRNG_NLGRP_MAX,
-		.input	= dnrmg_receive_user_skb,
-	};
-
-	dnrmg = netlink_kernel_create(&init_net, NETLINK_DNRTMSG, &cfg);
-	if (dnrmg == NULL) {
-		printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket");
-		return -ENOMEM;
-	}
-
-	rv = nf_register_net_hook(&init_net, &dnrmg_ops);
-	if (rv) {
-		netlink_kernel_release(dnrmg);
-	}
-
-	return rv;
-}
-
-static void __exit dn_rtmsg_fini(void)
-{
-	nf_unregister_net_hook(&init_net, &dnrmg_ops);
-	netlink_kernel_release(dnrmg);
-}
-
-
-MODULE_DESCRIPTION("DECnet Routing Message Grabulator");
-MODULE_AUTHOR("Steven Whitehouse <steve@chygwyn.com>");
-MODULE_LICENSE("GPL");
-MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_DNRTMSG);
-
-module_init(dn_rtmsg_init);
-module_exit(dn_rtmsg_fini);