1
2/*
3 * DECnet       An implementation of the DECnet protocol suite for the LINUX
4 *              operating system.  DECnet is implemented using the  BSD Socket
5 *              interface as the means of communication with the user level.
6 *
7 *              DECnet Routing Forwarding Information Base (Rules)
8 *
9 * Author:      Steve Whitehouse <SteveW@ACM.org>
10 *              Mostly copied from Alexey Kuznetsov's ipv4/fib_rules.c
11 *
12 *
13 * Changes:
14 *              Steve Whitehouse <steve@chygwyn.com>
15 *              Updated for Thomas Graf's generic rules
16 *
17 */
18#include <linux/net.h>
19#include <linux/init.h>
20#include <linux/netlink.h>
21#include <linux/rtnetlink.h>
22#include <linux/netdevice.h>
23#include <linux/spinlock.h>
24#include <linux/list.h>
25#include <linux/rcupdate.h>
26#include <net/neighbour.h>
27#include <net/dst.h>
28#include <net/flow.h>
29#include <net/fib_rules.h>
30#include <net/dn.h>
31#include <net/dn_fib.h>
32#include <net/dn_neigh.h>
33#include <net/dn_dev.h>
34#include <net/dn_route.h>
35
36static struct fib_rules_ops dn_fib_rules_ops;
37
38struct dn_fib_rule
39{
40	struct fib_rule		common;
41	unsigned char		dst_len;
42	unsigned char		src_len;
43	__le16			src;
44	__le16			srcmask;
45	__le16			dst;
46	__le16			dstmask;
47	__le16			srcmap;
48	u8			flags;
49};
50
51static struct dn_fib_rule default_rule = {
52	.common = {
53		.refcnt =		ATOMIC_INIT(2),
54		.pref =			0x7fff,
55		.table =		RT_TABLE_MAIN,
56		.action =		FR_ACT_TO_TBL,
57	},
58};
59
60static LIST_HEAD(dn_fib_rules);
61
62
63int dn_fib_lookup(struct flowi *flp, struct dn_fib_res *res)
64{
65	struct fib_lookup_arg arg = {
66		.result = res,
67	};
68	int err;
69
70	err = fib_rules_lookup(&dn_fib_rules_ops, flp, 0, &arg);
71	res->r = arg.rule;
72
73	return err;
74}
75
76static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
77			      int flags, struct fib_lookup_arg *arg)
78{
79	int err = -EAGAIN;
80	struct dn_fib_table *tbl;
81
82	switch(rule->action) {
83	case FR_ACT_TO_TBL:
84		break;
85
86	case FR_ACT_UNREACHABLE:
87		err = -ENETUNREACH;
88		goto errout;
89
90	case FR_ACT_PROHIBIT:
91		err = -EACCES;
92		goto errout;
93
94	case FR_ACT_BLACKHOLE:
95	default:
96		err = -EINVAL;
97		goto errout;
98	}
99
100	tbl = dn_fib_get_table(rule->table, 0);
101	if (tbl == NULL)
102		goto errout;
103
104	err = tbl->lookup(tbl, flp, (struct dn_fib_res *)arg->result);
105	if (err > 0)
106		err = -EAGAIN;
107errout:
108	return err;
109}
110
111static const struct nla_policy dn_fib_rule_policy[FRA_MAX+1] = {
112	FRA_GENERIC_POLICY,
113};
114
115static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
116{
117	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
118	__le16 daddr = fl->fld_dst;
119	__le16 saddr = fl->fld_src;
120
121	if (((saddr ^ r->src) & r->srcmask) ||
122	    ((daddr ^ r->dst) & r->dstmask))
123		return 0;
124
125	return 1;
126}
127
128static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
129				 struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
130				 struct nlattr **tb)
131{
132	int err = -EINVAL;
133	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
134
135	if (frh->tos)
136		goto  errout;
137
138	if (rule->table == RT_TABLE_UNSPEC) {
139		if (rule->action == FR_ACT_TO_TBL) {
140			struct dn_fib_table *table;
141
142			table = dn_fib_empty_table();
143			if (table == NULL) {
144				err = -ENOBUFS;
145				goto errout;
146			}
147
148			rule->table = table->n;
149		}
150	}
151
152	if (frh->src_len)
153		r->src = nla_get_le16(tb[FRA_SRC]);
154
155	if (frh->dst_len)
156		r->dst = nla_get_le16(tb[FRA_DST]);
157
158	r->src_len = frh->src_len;
159	r->srcmask = dnet_make_mask(r->src_len);
160	r->dst_len = frh->dst_len;
161	r->dstmask = dnet_make_mask(r->dst_len);
162	err = 0;
163errout:
164	return err;
165}
166
167static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
168			       struct nlattr **tb)
169{
170	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
171
172	if (frh->src_len && (r->src_len != frh->src_len))
173		return 0;
174
175	if (frh->dst_len && (r->dst_len != frh->dst_len))
176		return 0;
177
178	if (frh->src_len && (r->src != nla_get_le16(tb[FRA_SRC])))
179		return 0;
180
181	if (frh->dst_len && (r->dst != nla_get_le16(tb[FRA_DST])))
182		return 0;
183
184	return 1;
185}
186
187unsigned dnet_addr_type(__le16 addr)
188{
189	struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
190	struct dn_fib_res res;
191	unsigned ret = RTN_UNICAST;
192	struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
193
194	res.r = NULL;
195
196	if (tb) {
197		if (!tb->lookup(tb, &fl, &res)) {
198			ret = res.type;
199			dn_fib_res_put(&res);
200		}
201	}
202	return ret;
203}
204
205static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
206			    struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
207{
208	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
209
210	frh->family = AF_DECnet;
211	frh->dst_len = r->dst_len;
212	frh->src_len = r->src_len;
213	frh->tos = 0;
214
215	if (r->dst_len)
216		NLA_PUT_LE16(skb, FRA_DST, r->dst);
217	if (r->src_len)
218		NLA_PUT_LE16(skb, FRA_SRC, r->src);
219
220	return 0;
221
222nla_put_failure:
223	return -ENOBUFS;
224}
225
226static u32 dn_fib_rule_default_pref(void)
227{
228	struct list_head *pos;
229	struct fib_rule *rule;
230
231	if (!list_empty(&dn_fib_rules)) {
232		pos = dn_fib_rules.next;
233		if (pos->next != &dn_fib_rules) {
234			rule = list_entry(pos->next, struct fib_rule, list);
235			if (rule->pref)
236				return rule->pref - 1;
237		}
238	}
239
240	return 0;
241}
242
243static void dn_fib_rule_flush_cache(void)
244{
245	dn_rt_cache_flush(-1);
246}
247
248static struct fib_rules_ops dn_fib_rules_ops = {
249	.family		= AF_DECnet,
250	.rule_size	= sizeof(struct dn_fib_rule),
251	.addr_size	= sizeof(u16),
252	.action		= dn_fib_rule_action,
253	.match		= dn_fib_rule_match,
254	.configure	= dn_fib_rule_configure,
255	.compare	= dn_fib_rule_compare,
256	.fill		= dn_fib_rule_fill,
257	.default_pref	= dn_fib_rule_default_pref,
258	.flush_cache	= dn_fib_rule_flush_cache,
259	.nlgroup	= RTNLGRP_DECnet_RULE,
260	.policy		= dn_fib_rule_policy,
261	.rules_list	= &dn_fib_rules,
262	.owner		= THIS_MODULE,
263};
264
265void __init dn_fib_rules_init(void)
266{
267	list_add_tail(&default_rule.common.list, &dn_fib_rules);
268	fib_rules_register(&dn_fib_rules_ops);
269}
270
271void __exit dn_fib_rules_cleanup(void)
272{
273	fib_rules_unregister(&dn_fib_rules_ops);
274}
275