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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 <linux/export.h>
27 #include <net/neighbour.h>
28 #include <net/dst.h>
29 #include <net/flow.h>
30 #include <net/fib_rules.h>
31 #include <net/dn.h>
32 #include <net/dn_fib.h>
33 #include <net/dn_neigh.h>
34 #include <net/dn_dev.h>
35 #include <net/dn_route.h>
36 
37 static struct fib_rules_ops *dn_fib_rules_ops;
38 
39 struct dn_fib_rule
40 {
41 	struct fib_rule		common;
42 	unsigned char		dst_len;
43 	unsigned char		src_len;
44 	__le16			src;
45 	__le16			srcmask;
46 	__le16			dst;
47 	__le16			dstmask;
48 	__le16			srcmap;
49 	u8			flags;
50 };
51 
52 
dn_fib_lookup(struct flowidn * flp,struct dn_fib_res * res)53 int dn_fib_lookup(struct flowidn *flp, struct dn_fib_res *res)
54 {
55 	struct fib_lookup_arg arg = {
56 		.result = res,
57 	};
58 	int err;
59 
60 	err = fib_rules_lookup(dn_fib_rules_ops,
61 			       flowidn_to_flowi(flp), 0, &arg);
62 	res->r = arg.rule;
63 
64 	return err;
65 }
66 
dn_fib_rule_action(struct fib_rule * rule,struct flowi * flp,int flags,struct fib_lookup_arg * arg)67 static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
68 			      int flags, struct fib_lookup_arg *arg)
69 {
70 	struct flowidn *fld = &flp->u.dn;
71 	int err = -EAGAIN;
72 	struct dn_fib_table *tbl;
73 
74 	switch(rule->action) {
75 	case FR_ACT_TO_TBL:
76 		break;
77 
78 	case FR_ACT_UNREACHABLE:
79 		err = -ENETUNREACH;
80 		goto errout;
81 
82 	case FR_ACT_PROHIBIT:
83 		err = -EACCES;
84 		goto errout;
85 
86 	case FR_ACT_BLACKHOLE:
87 	default:
88 		err = -EINVAL;
89 		goto errout;
90 	}
91 
92 	tbl = dn_fib_get_table(rule->table, 0);
93 	if (tbl == NULL)
94 		goto errout;
95 
96 	err = tbl->lookup(tbl, fld, (struct dn_fib_res *)arg->result);
97 	if (err > 0)
98 		err = -EAGAIN;
99 errout:
100 	return err;
101 }
102 
103 static const struct nla_policy dn_fib_rule_policy[FRA_MAX+1] = {
104 	FRA_GENERIC_POLICY,
105 };
106 
dn_fib_rule_match(struct fib_rule * rule,struct flowi * fl,int flags)107 static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
108 {
109 	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
110 	struct flowidn *fld = &fl->u.dn;
111 	__le16 daddr = fld->daddr;
112 	__le16 saddr = fld->saddr;
113 
114 	if (((saddr ^ r->src) & r->srcmask) ||
115 	    ((daddr ^ r->dst) & r->dstmask))
116 		return 0;
117 
118 	return 1;
119 }
120 
dn_fib_rule_configure(struct fib_rule * rule,struct sk_buff * skb,struct fib_rule_hdr * frh,struct nlattr ** tb)121 static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
122 				 struct fib_rule_hdr *frh,
123 				 struct nlattr **tb)
124 {
125 	int err = -EINVAL;
126 	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
127 
128 	if (frh->tos)
129 		goto  errout;
130 
131 	if (rule->table == RT_TABLE_UNSPEC) {
132 		if (rule->action == FR_ACT_TO_TBL) {
133 			struct dn_fib_table *table;
134 
135 			table = dn_fib_empty_table();
136 			if (table == NULL) {
137 				err = -ENOBUFS;
138 				goto errout;
139 			}
140 
141 			rule->table = table->n;
142 		}
143 	}
144 
145 	if (frh->src_len)
146 		r->src = nla_get_le16(tb[FRA_SRC]);
147 
148 	if (frh->dst_len)
149 		r->dst = nla_get_le16(tb[FRA_DST]);
150 
151 	r->src_len = frh->src_len;
152 	r->srcmask = dnet_make_mask(r->src_len);
153 	r->dst_len = frh->dst_len;
154 	r->dstmask = dnet_make_mask(r->dst_len);
155 	err = 0;
156 errout:
157 	return err;
158 }
159 
dn_fib_rule_compare(struct fib_rule * rule,struct fib_rule_hdr * frh,struct nlattr ** tb)160 static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
161 			       struct nlattr **tb)
162 {
163 	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
164 
165 	if (frh->src_len && (r->src_len != frh->src_len))
166 		return 0;
167 
168 	if (frh->dst_len && (r->dst_len != frh->dst_len))
169 		return 0;
170 
171 	if (frh->src_len && (r->src != nla_get_le16(tb[FRA_SRC])))
172 		return 0;
173 
174 	if (frh->dst_len && (r->dst != nla_get_le16(tb[FRA_DST])))
175 		return 0;
176 
177 	return 1;
178 }
179 
dnet_addr_type(__le16 addr)180 unsigned int dnet_addr_type(__le16 addr)
181 {
182 	struct flowidn fld = { .daddr = addr };
183 	struct dn_fib_res res;
184 	unsigned int ret = RTN_UNICAST;
185 	struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
186 
187 	res.r = NULL;
188 
189 	if (tb) {
190 		if (!tb->lookup(tb, &fld, &res)) {
191 			ret = res.type;
192 			dn_fib_res_put(&res);
193 		}
194 	}
195 	return ret;
196 }
197 
dn_fib_rule_fill(struct fib_rule * rule,struct sk_buff * skb,struct fib_rule_hdr * frh)198 static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
199 			    struct fib_rule_hdr *frh)
200 {
201 	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
202 
203 	frh->dst_len = r->dst_len;
204 	frh->src_len = r->src_len;
205 	frh->tos = 0;
206 
207 	if ((r->dst_len &&
208 	     nla_put_le16(skb, FRA_DST, r->dst)) ||
209 	    (r->src_len &&
210 	     nla_put_le16(skb, FRA_SRC, r->src)))
211 		goto nla_put_failure;
212 	return 0;
213 
214 nla_put_failure:
215 	return -ENOBUFS;
216 }
217 
dn_fib_rule_flush_cache(struct fib_rules_ops * ops)218 static void dn_fib_rule_flush_cache(struct fib_rules_ops *ops)
219 {
220 	dn_rt_cache_flush(-1);
221 }
222 
223 static const struct fib_rules_ops __net_initconst dn_fib_rules_ops_template = {
224 	.family		= AF_DECnet,
225 	.rule_size	= sizeof(struct dn_fib_rule),
226 	.addr_size	= sizeof(u16),
227 	.action		= dn_fib_rule_action,
228 	.match		= dn_fib_rule_match,
229 	.configure	= dn_fib_rule_configure,
230 	.compare	= dn_fib_rule_compare,
231 	.fill		= dn_fib_rule_fill,
232 	.flush_cache	= dn_fib_rule_flush_cache,
233 	.nlgroup	= RTNLGRP_DECnet_RULE,
234 	.policy		= dn_fib_rule_policy,
235 	.owner		= THIS_MODULE,
236 	.fro_net	= &init_net,
237 };
238 
dn_fib_rules_init(void)239 void __init dn_fib_rules_init(void)
240 {
241 	dn_fib_rules_ops =
242 		fib_rules_register(&dn_fib_rules_ops_template, &init_net);
243 	BUG_ON(IS_ERR(dn_fib_rules_ops));
244 	BUG_ON(fib_default_rule_add(dn_fib_rules_ops, 0x7fff,
245 			            RT_TABLE_MAIN, 0));
246 }
247 
dn_fib_rules_cleanup(void)248 void __exit dn_fib_rules_cleanup(void)
249 {
250 	rtnl_lock();
251 	fib_rules_unregister(dn_fib_rules_ops);
252 	rtnl_unlock();
253 	rcu_barrier();
254 }
255 
256 
257