1// SPDX-License-Identifier: GPL-2.0
2#include <linux/errno.h>
3#include <linux/ip.h>
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/skbuff.h>
7#include <linux/socket.h>
8#include <linux/types.h>
9#include <net/checksum.h>
10#include <net/dst_cache.h>
11#include <net/ip.h>
12#include <net/ip6_fib.h>
13#include <net/ip6_route.h>
14#include <net/lwtunnel.h>
15#include <net/protocol.h>
16#include <uapi/linux/ila.h>
17#include "ila.h"
18
19struct ila_lwt {
20	struct ila_params p;
21	struct dst_cache dst_cache;
22	u32 connected : 1;
23	u32 lwt_output : 1;
24};
25
26static inline struct ila_lwt *ila_lwt_lwtunnel(
27	struct lwtunnel_state *lwt)
28{
29	return (struct ila_lwt *)lwt->data;
30}
31
32static inline struct ila_params *ila_params_lwtunnel(
33	struct lwtunnel_state *lwt)
34{
35	return &ila_lwt_lwtunnel(lwt)->p;
36}
37
38static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
39{
40	struct dst_entry *orig_dst = skb_dst(skb);
41	struct rt6_info *rt = (struct rt6_info *)orig_dst;
42	struct ila_lwt *ilwt = ila_lwt_lwtunnel(orig_dst->lwtstate);
43	struct dst_entry *dst;
44	int err = -EINVAL;
45
46	if (skb->protocol != htons(ETH_P_IPV6))
47		goto drop;
48
49	if (ilwt->lwt_output)
50		ila_update_ipv6_locator(skb,
51					ila_params_lwtunnel(orig_dst->lwtstate),
52					true);
53
54	if (rt->rt6i_flags & (RTF_GATEWAY | RTF_CACHE)) {
55		/* Already have a next hop address in route, no need for
56		 * dest cache route.
57		 */
58		return orig_dst->lwtstate->orig_output(net, sk, skb);
59	}
60
61	dst = dst_cache_get(&ilwt->dst_cache);
62	if (unlikely(!dst)) {
63		struct ipv6hdr *ip6h = ipv6_hdr(skb);
64		struct flowi6 fl6;
65
66		/* Lookup a route for the new destination. Take into
67		 * account that the base route may already have a gateway.
68		 */
69
70		memset(&fl6, 0, sizeof(fl6));
71		fl6.flowi6_oif = orig_dst->dev->ifindex;
72		fl6.flowi6_iif = LOOPBACK_IFINDEX;
73		fl6.daddr = *rt6_nexthop((struct rt6_info *)orig_dst,
74					 &ip6h->daddr);
75
76		dst = ip6_route_output(net, NULL, &fl6);
77		if (dst->error) {
78			err = -EHOSTUNREACH;
79			dst_release(dst);
80			goto drop;
81		}
82
83		dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
84		if (IS_ERR(dst)) {
85			err = PTR_ERR(dst);
86			goto drop;
87		}
88
89		if (ilwt->connected)
90			dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
91	}
92
93	skb_dst_set(skb, dst);
94	return dst_output(net, sk, skb);
95
96drop:
97	kfree_skb(skb);
98	return err;
99}
100
101static int ila_input(struct sk_buff *skb)
102{
103	struct dst_entry *dst = skb_dst(skb);
104	struct ila_lwt *ilwt = ila_lwt_lwtunnel(dst->lwtstate);
105
106	if (skb->protocol != htons(ETH_P_IPV6))
107		goto drop;
108
109	if (!ilwt->lwt_output)
110		ila_update_ipv6_locator(skb,
111					ila_params_lwtunnel(dst->lwtstate),
112					false);
113
114	return dst->lwtstate->orig_input(skb);
115
116drop:
117	kfree_skb(skb);
118	return -EINVAL;
119}
120
121static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
122	[ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
123	[ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
124	[ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
125	[ILA_ATTR_HOOK_TYPE] = { .type = NLA_U8, },
126};
127
128static int ila_build_state(struct net *net, struct nlattr *nla,
129			   unsigned int family, const void *cfg,
130			   struct lwtunnel_state **ts,
131			   struct netlink_ext_ack *extack)
132{
133	struct ila_lwt *ilwt;
134	struct ila_params *p;
135	struct nlattr *tb[ILA_ATTR_MAX + 1];
136	struct lwtunnel_state *newts;
137	const struct fib6_config *cfg6 = cfg;
138	struct ila_addr *iaddr;
139	u8 ident_type = ILA_ATYPE_USE_FORMAT;
140	u8 hook_type = ILA_HOOK_ROUTE_OUTPUT;
141	u8 csum_mode = ILA_CSUM_NO_ACTION;
142	bool lwt_output = true;
143	u8 eff_ident_type;
144	int ret;
145
146	if (family != AF_INET6)
147		return -EINVAL;
148
149	ret = nla_parse_nested_deprecated(tb, ILA_ATTR_MAX, nla,
150					  ila_nl_policy, extack);
151	if (ret < 0)
152		return ret;
153
154	if (!tb[ILA_ATTR_LOCATOR])
155		return -EINVAL;
156
157	iaddr = (struct ila_addr *)&cfg6->fc_dst;
158
159	if (tb[ILA_ATTR_IDENT_TYPE])
160		ident_type = nla_get_u8(tb[ILA_ATTR_IDENT_TYPE]);
161
162	if (ident_type == ILA_ATYPE_USE_FORMAT) {
163		/* Infer identifier type from type field in formatted
164		 * identifier.
165		 */
166
167		if (cfg6->fc_dst_len < 8 * sizeof(struct ila_locator) + 3) {
168			/* Need to have full locator and at least type field
169			 * included in destination
170			 */
171			return -EINVAL;
172		}
173
174		eff_ident_type = iaddr->ident.type;
175	} else {
176		eff_ident_type = ident_type;
177	}
178
179	switch (eff_ident_type) {
180	case ILA_ATYPE_IID:
181		/* Don't allow ILA for IID type */
182		return -EINVAL;
183	case ILA_ATYPE_LUID:
184		break;
185	case ILA_ATYPE_VIRT_V4:
186	case ILA_ATYPE_VIRT_UNI_V6:
187	case ILA_ATYPE_VIRT_MULTI_V6:
188	case ILA_ATYPE_NONLOCAL_ADDR:
189		/* These ILA formats are not supported yet. */
190	default:
191		return -EINVAL;
192	}
193
194	if (tb[ILA_ATTR_HOOK_TYPE])
195		hook_type = nla_get_u8(tb[ILA_ATTR_HOOK_TYPE]);
196
197	switch (hook_type) {
198	case ILA_HOOK_ROUTE_OUTPUT:
199		lwt_output = true;
200		break;
201	case ILA_HOOK_ROUTE_INPUT:
202		lwt_output = false;
203		break;
204	default:
205		return -EINVAL;
206	}
207
208	if (tb[ILA_ATTR_CSUM_MODE])
209		csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
210
211	if (csum_mode == ILA_CSUM_NEUTRAL_MAP &&
212	    ila_csum_neutral_set(iaddr->ident)) {
213		/* Don't allow translation if checksum neutral bit is
214		 * configured and it's set in the SIR address.
215		 */
216		return -EINVAL;
217	}
218
219	newts = lwtunnel_state_alloc(sizeof(*ilwt));
220	if (!newts)
221		return -ENOMEM;
222
223	ilwt = ila_lwt_lwtunnel(newts);
224	ret = dst_cache_init(&ilwt->dst_cache, GFP_ATOMIC);
225	if (ret) {
226		kfree(newts);
227		return ret;
228	}
229
230	ilwt->lwt_output = !!lwt_output;
231
232	p = ila_params_lwtunnel(newts);
233
234	p->csum_mode = csum_mode;
235	p->ident_type = ident_type;
236	p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
237
238	/* Precompute checksum difference for translation since we
239	 * know both the old locator and the new one.
240	 */
241	p->locator_match = iaddr->loc;
242
243	ila_init_saved_csum(p);
244
245	newts->type = LWTUNNEL_ENCAP_ILA;
246	newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
247			LWTUNNEL_STATE_INPUT_REDIRECT;
248
249	if (cfg6->fc_dst_len == 8 * sizeof(struct in6_addr))
250		ilwt->connected = 1;
251
252	*ts = newts;
253
254	return 0;
255}
256
257static void ila_destroy_state(struct lwtunnel_state *lwt)
258{
259	dst_cache_destroy(&ila_lwt_lwtunnel(lwt)->dst_cache);
260}
261
262static int ila_fill_encap_info(struct sk_buff *skb,
263			       struct lwtunnel_state *lwtstate)
264{
265	struct ila_params *p = ila_params_lwtunnel(lwtstate);
266	struct ila_lwt *ilwt = ila_lwt_lwtunnel(lwtstate);
267
268	if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
269			      ILA_ATTR_PAD))
270		goto nla_put_failure;
271
272	if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
273		goto nla_put_failure;
274
275	if (nla_put_u8(skb, ILA_ATTR_IDENT_TYPE, (__force u8)p->ident_type))
276		goto nla_put_failure;
277
278	if (nla_put_u8(skb, ILA_ATTR_HOOK_TYPE,
279		       ilwt->lwt_output ? ILA_HOOK_ROUTE_OUTPUT :
280					  ILA_HOOK_ROUTE_INPUT))
281		goto nla_put_failure;
282
283	return 0;
284
285nla_put_failure:
286	return -EMSGSIZE;
287}
288
289static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
290{
291	return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
292	       nla_total_size(sizeof(u8)) +        /* ILA_ATTR_CSUM_MODE */
293	       nla_total_size(sizeof(u8)) +        /* ILA_ATTR_IDENT_TYPE */
294	       nla_total_size(sizeof(u8)) +        /* ILA_ATTR_HOOK_TYPE */
295	       0;
296}
297
298static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
299{
300	struct ila_params *a_p = ila_params_lwtunnel(a);
301	struct ila_params *b_p = ila_params_lwtunnel(b);
302
303	return (a_p->locator.v64 != b_p->locator.v64);
304}
305
306static const struct lwtunnel_encap_ops ila_encap_ops = {
307	.build_state = ila_build_state,
308	.destroy_state = ila_destroy_state,
309	.output = ila_output,
310	.input = ila_input,
311	.fill_encap = ila_fill_encap_info,
312	.get_encap_size = ila_encap_nlsize,
313	.cmp_encap = ila_encap_cmp,
314	.owner = THIS_MODULE,
315};
316
317int ila_lwt_init(void)
318{
319	return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
320}
321
322void ila_lwt_fini(void)
323{
324	lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
325}
326