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
19 struct ila_lwt {
20 struct ila_params p;
21 struct dst_cache dst_cache;
22 u32 connected : 1;
23 u32 lwt_output : 1;
24 };
25
26 static inline struct ila_lwt *ila_lwt_lwtunnel(
27 struct lwtunnel_state *lwt)
28 {
29 return (struct ila_lwt *)lwt->data;
30 }
31
32 static inline struct ila_params *ila_params_lwtunnel(
33 struct lwtunnel_state *lwt)
34 {
35 return &ila_lwt_lwtunnel(lwt)->p;
36 }
37
38 static 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 = dst_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 local_bh_disable();
62 dst = dst_cache_get(&ilwt->dst_cache);
63 local_bh_enable();
64 if (unlikely(!dst)) {
65 struct ipv6hdr *ip6h = ipv6_hdr(skb);
66 struct flowi6 fl6;
67
68 /* Lookup a route for the new destination. Take into
69 * account that the base route may already have a gateway.
70 */
71
72 memset(&fl6, 0, sizeof(fl6));
73 fl6.flowi6_oif = orig_dst->dev->ifindex;
74 fl6.flowi6_iif = LOOPBACK_IFINDEX;
75 fl6.daddr = *rt6_nexthop(dst_rt6_info(orig_dst),
76 &ip6h->daddr);
77
78 dst = ip6_route_output(net, NULL, &fl6);
79 if (dst->error) {
80 err = -EHOSTUNREACH;
81 dst_release(dst);
82 goto drop;
83 }
84
85 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
86 if (IS_ERR(dst)) {
87 err = PTR_ERR(dst);
88 goto drop;
89 }
90
91 if (ilwt->connected) {
92 local_bh_disable();
93 dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
94 local_bh_enable();
95 }
96 }
97
98 skb_dst_set(skb, dst);
99 return dst_output(net, sk, skb);
100
101 drop:
102 kfree_skb(skb);
103 return err;
104 }
105
106 static int ila_input(struct sk_buff *skb)
107 {
108 struct dst_entry *dst = skb_dst(skb);
109 struct ila_lwt *ilwt = ila_lwt_lwtunnel(dst->lwtstate);
110
111 if (skb->protocol != htons(ETH_P_IPV6))
112 goto drop;
113
114 if (!ilwt->lwt_output)
115 ila_update_ipv6_locator(skb,
116 ila_params_lwtunnel(dst->lwtstate),
117 false);
118
119 return dst->lwtstate->orig_input(skb);
120
121 drop:
122 kfree_skb(skb);
123 return -EINVAL;
124 }
125
126 static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
127 [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
128 [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
129 [ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
130 [ILA_ATTR_HOOK_TYPE] = { .type = NLA_U8, },
131 };
132
133 static int ila_build_state(struct net *net, struct nlattr *nla,
134 unsigned int family, const void *cfg,
135 struct lwtunnel_state **ts,
136 struct netlink_ext_ack *extack)
137 {
138 struct ila_lwt *ilwt;
139 struct ila_params *p;
140 struct nlattr *tb[ILA_ATTR_MAX + 1];
141 struct lwtunnel_state *newts;
142 const struct fib6_config *cfg6 = cfg;
143 struct ila_addr *iaddr;
144 u8 ident_type = ILA_ATYPE_USE_FORMAT;
145 u8 hook_type = ILA_HOOK_ROUTE_OUTPUT;
146 u8 csum_mode = ILA_CSUM_NO_ACTION;
147 bool lwt_output = true;
148 u8 eff_ident_type;
149 int ret;
150
151 if (family != AF_INET6)
152 return -EINVAL;
153
154 ret = nla_parse_nested_deprecated(tb, ILA_ATTR_MAX, nla,
155 ila_nl_policy, extack);
156 if (ret < 0)
157 return ret;
158
159 if (!tb[ILA_ATTR_LOCATOR])
160 return -EINVAL;
161
162 iaddr = (struct ila_addr *)&cfg6->fc_dst;
163
164 if (tb[ILA_ATTR_IDENT_TYPE])
165 ident_type = nla_get_u8(tb[ILA_ATTR_IDENT_TYPE]);
166
167 if (ident_type == ILA_ATYPE_USE_FORMAT) {
168 /* Infer identifier type from type field in formatted
169 * identifier.
170 */
171
172 if (cfg6->fc_dst_len < 8 * sizeof(struct ila_locator) + 3) {
173 /* Need to have full locator and at least type field
174 * included in destination
175 */
176 return -EINVAL;
177 }
178
179 eff_ident_type = iaddr->ident.type;
180 } else {
181 eff_ident_type = ident_type;
182 }
183
184 switch (eff_ident_type) {
185 case ILA_ATYPE_IID:
186 /* Don't allow ILA for IID type */
187 return -EINVAL;
188 case ILA_ATYPE_LUID:
189 break;
190 case ILA_ATYPE_VIRT_V4:
191 case ILA_ATYPE_VIRT_UNI_V6:
192 case ILA_ATYPE_VIRT_MULTI_V6:
193 case ILA_ATYPE_NONLOCAL_ADDR:
194 /* These ILA formats are not supported yet. */
195 default:
196 return -EINVAL;
197 }
198
199 if (tb[ILA_ATTR_HOOK_TYPE])
200 hook_type = nla_get_u8(tb[ILA_ATTR_HOOK_TYPE]);
201
202 switch (hook_type) {
203 case ILA_HOOK_ROUTE_OUTPUT:
204 lwt_output = true;
205 break;
206 case ILA_HOOK_ROUTE_INPUT:
207 lwt_output = false;
208 break;
209 default:
210 return -EINVAL;
211 }
212
213 if (tb[ILA_ATTR_CSUM_MODE])
214 csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
215
216 if (csum_mode == ILA_CSUM_NEUTRAL_MAP &&
217 ila_csum_neutral_set(iaddr->ident)) {
218 /* Don't allow translation if checksum neutral bit is
219 * configured and it's set in the SIR address.
220 */
221 return -EINVAL;
222 }
223
224 newts = lwtunnel_state_alloc(sizeof(*ilwt));
225 if (!newts)
226 return -ENOMEM;
227
228 ilwt = ila_lwt_lwtunnel(newts);
229 ret = dst_cache_init(&ilwt->dst_cache, GFP_ATOMIC);
230 if (ret) {
231 kfree(newts);
232 return ret;
233 }
234
235 ilwt->lwt_output = !!lwt_output;
236
237 p = ila_params_lwtunnel(newts);
238
239 p->csum_mode = csum_mode;
240 p->ident_type = ident_type;
241 p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
242
243 /* Precompute checksum difference for translation since we
244 * know both the old locator and the new one.
245 */
246 p->locator_match = iaddr->loc;
247
248 ila_init_saved_csum(p);
249
250 newts->type = LWTUNNEL_ENCAP_ILA;
251 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
252 LWTUNNEL_STATE_INPUT_REDIRECT;
253
254 if (cfg6->fc_dst_len == 8 * sizeof(struct in6_addr))
255 ilwt->connected = 1;
256
257 *ts = newts;
258
259 return 0;
260 }
261
262 static void ila_destroy_state(struct lwtunnel_state *lwt)
263 {
264 dst_cache_destroy(&ila_lwt_lwtunnel(lwt)->dst_cache);
265 }
266
267 static int ila_fill_encap_info(struct sk_buff *skb,
268 struct lwtunnel_state *lwtstate)
269 {
270 struct ila_params *p = ila_params_lwtunnel(lwtstate);
271 struct ila_lwt *ilwt = ila_lwt_lwtunnel(lwtstate);
272
273 if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
274 ILA_ATTR_PAD))
275 goto nla_put_failure;
276
277 if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
278 goto nla_put_failure;
279
280 if (nla_put_u8(skb, ILA_ATTR_IDENT_TYPE, (__force u8)p->ident_type))
281 goto nla_put_failure;
282
283 if (nla_put_u8(skb, ILA_ATTR_HOOK_TYPE,
284 ilwt->lwt_output ? ILA_HOOK_ROUTE_OUTPUT :
285 ILA_HOOK_ROUTE_INPUT))
286 goto nla_put_failure;
287
288 return 0;
289
290 nla_put_failure:
291 return -EMSGSIZE;
292 }
293
294 static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
295 {
296 return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
297 nla_total_size(sizeof(u8)) + /* ILA_ATTR_CSUM_MODE */
298 nla_total_size(sizeof(u8)) + /* ILA_ATTR_IDENT_TYPE */
299 nla_total_size(sizeof(u8)) + /* ILA_ATTR_HOOK_TYPE */
300 0;
301 }
302
303 static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
304 {
305 struct ila_params *a_p = ila_params_lwtunnel(a);
306 struct ila_params *b_p = ila_params_lwtunnel(b);
307
308 return (a_p->locator.v64 != b_p->locator.v64);
309 }
310
311 static const struct lwtunnel_encap_ops ila_encap_ops = {
312 .build_state = ila_build_state,
313 .destroy_state = ila_destroy_state,
314 .output = ila_output,
315 .input = ila_input,
316 .fill_encap = ila_fill_encap_info,
317 .get_encap_size = ila_encap_nlsize,
318 .cmp_encap = ila_encap_cmp,
319 .owner = THIS_MODULE,
320 };
321
322 int ila_lwt_init(void)
323 {
324 return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
325 }
326
327 void ila_lwt_fini(void)
328 {
329 lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
330 }
331
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