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
ila_lwt_lwtunnel(struct lwtunnel_state * lwt)26 static inline struct ila_lwt *ila_lwt_lwtunnel(
27 struct lwtunnel_state *lwt)
28 {
29 return (struct ila_lwt *)lwt->data;
30 }
31
ila_params_lwtunnel(struct lwtunnel_state * lwt)32 static inline struct ila_params *ila_params_lwtunnel(
33 struct lwtunnel_state *lwt)
34 {
35 return &ila_lwt_lwtunnel(lwt)->p;
36 }
37
ila_output(struct net * net,struct sock * sk,struct sk_buff * skb)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 /* cache only if we don't create a dst reference loop */
92 if (ilwt->connected && orig_dst->lwtstate != dst->lwtstate) {
93 local_bh_disable();
94 dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
95 local_bh_enable();
96 }
97 }
98
99 skb_dst_drop(skb);
100 skb_dst_set(skb, dst);
101 return dst_output(net, sk, skb);
102
103 drop:
104 kfree_skb(skb);
105 return err;
106 }
107
ila_input(struct sk_buff * skb)108 static int ila_input(struct sk_buff *skb)
109 {
110 struct dst_entry *dst = skb_dst(skb);
111 struct ila_lwt *ilwt = ila_lwt_lwtunnel(dst->lwtstate);
112
113 if (skb->protocol != htons(ETH_P_IPV6))
114 goto drop;
115
116 if (!ilwt->lwt_output)
117 ila_update_ipv6_locator(skb,
118 ila_params_lwtunnel(dst->lwtstate),
119 false);
120
121 return dst->lwtstate->orig_input(skb);
122
123 drop:
124 kfree_skb(skb);
125 return -EINVAL;
126 }
127
128 static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
129 [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
130 [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
131 [ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
132 [ILA_ATTR_HOOK_TYPE] = { .type = NLA_U8, },
133 };
134
ila_build_state(struct net * net,struct nlattr * nla,unsigned int family,const void * cfg,struct lwtunnel_state ** ts,struct netlink_ext_ack * extack)135 static int ila_build_state(struct net *net, struct nlattr *nla,
136 unsigned int family, const void *cfg,
137 struct lwtunnel_state **ts,
138 struct netlink_ext_ack *extack)
139 {
140 struct ila_lwt *ilwt;
141 struct ila_params *p;
142 struct nlattr *tb[ILA_ATTR_MAX + 1];
143 struct lwtunnel_state *newts;
144 const struct fib6_config *cfg6 = cfg;
145 struct ila_addr *iaddr;
146 u8 ident_type = ILA_ATYPE_USE_FORMAT;
147 u8 hook_type = ILA_HOOK_ROUTE_OUTPUT;
148 u8 csum_mode = ILA_CSUM_NO_ACTION;
149 bool lwt_output = true;
150 u8 eff_ident_type;
151 int ret;
152
153 if (family != AF_INET6)
154 return -EINVAL;
155
156 ret = nla_parse_nested_deprecated(tb, ILA_ATTR_MAX, nla,
157 ila_nl_policy, extack);
158 if (ret < 0)
159 return ret;
160
161 if (!tb[ILA_ATTR_LOCATOR])
162 return -EINVAL;
163
164 iaddr = (struct ila_addr *)&cfg6->fc_dst;
165
166 if (tb[ILA_ATTR_IDENT_TYPE])
167 ident_type = nla_get_u8(tb[ILA_ATTR_IDENT_TYPE]);
168
169 if (ident_type == ILA_ATYPE_USE_FORMAT) {
170 /* Infer identifier type from type field in formatted
171 * identifier.
172 */
173
174 if (cfg6->fc_dst_len < 8 * sizeof(struct ila_locator) + 3) {
175 /* Need to have full locator and at least type field
176 * included in destination
177 */
178 return -EINVAL;
179 }
180
181 eff_ident_type = iaddr->ident.type;
182 } else {
183 eff_ident_type = ident_type;
184 }
185
186 switch (eff_ident_type) {
187 case ILA_ATYPE_IID:
188 /* Don't allow ILA for IID type */
189 return -EINVAL;
190 case ILA_ATYPE_LUID:
191 break;
192 case ILA_ATYPE_VIRT_V4:
193 case ILA_ATYPE_VIRT_UNI_V6:
194 case ILA_ATYPE_VIRT_MULTI_V6:
195 case ILA_ATYPE_NONLOCAL_ADDR:
196 /* These ILA formats are not supported yet. */
197 default:
198 return -EINVAL;
199 }
200
201 if (tb[ILA_ATTR_HOOK_TYPE])
202 hook_type = nla_get_u8(tb[ILA_ATTR_HOOK_TYPE]);
203
204 switch (hook_type) {
205 case ILA_HOOK_ROUTE_OUTPUT:
206 lwt_output = true;
207 break;
208 case ILA_HOOK_ROUTE_INPUT:
209 lwt_output = false;
210 break;
211 default:
212 return -EINVAL;
213 }
214
215 if (tb[ILA_ATTR_CSUM_MODE])
216 csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
217
218 if (csum_mode == ILA_CSUM_NEUTRAL_MAP &&
219 ila_csum_neutral_set(iaddr->ident)) {
220 /* Don't allow translation if checksum neutral bit is
221 * configured and it's set in the SIR address.
222 */
223 return -EINVAL;
224 }
225
226 newts = lwtunnel_state_alloc(sizeof(*ilwt));
227 if (!newts)
228 return -ENOMEM;
229
230 ilwt = ila_lwt_lwtunnel(newts);
231 ret = dst_cache_init(&ilwt->dst_cache, GFP_ATOMIC);
232 if (ret) {
233 kfree(newts);
234 return ret;
235 }
236
237 ilwt->lwt_output = !!lwt_output;
238
239 p = ila_params_lwtunnel(newts);
240
241 p->csum_mode = csum_mode;
242 p->ident_type = ident_type;
243 p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
244
245 /* Precompute checksum difference for translation since we
246 * know both the old locator and the new one.
247 */
248 p->locator_match = iaddr->loc;
249
250 ila_init_saved_csum(p);
251
252 newts->type = LWTUNNEL_ENCAP_ILA;
253 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
254 LWTUNNEL_STATE_INPUT_REDIRECT;
255
256 if (cfg6->fc_dst_len == 8 * sizeof(struct in6_addr))
257 ilwt->connected = 1;
258
259 *ts = newts;
260
261 return 0;
262 }
263
ila_destroy_state(struct lwtunnel_state * lwt)264 static void ila_destroy_state(struct lwtunnel_state *lwt)
265 {
266 dst_cache_destroy(&ila_lwt_lwtunnel(lwt)->dst_cache);
267 }
268
ila_fill_encap_info(struct sk_buff * skb,struct lwtunnel_state * lwtstate)269 static int ila_fill_encap_info(struct sk_buff *skb,
270 struct lwtunnel_state *lwtstate)
271 {
272 struct ila_params *p = ila_params_lwtunnel(lwtstate);
273 struct ila_lwt *ilwt = ila_lwt_lwtunnel(lwtstate);
274
275 if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
276 ILA_ATTR_PAD))
277 goto nla_put_failure;
278
279 if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
280 goto nla_put_failure;
281
282 if (nla_put_u8(skb, ILA_ATTR_IDENT_TYPE, (__force u8)p->ident_type))
283 goto nla_put_failure;
284
285 if (nla_put_u8(skb, ILA_ATTR_HOOK_TYPE,
286 ilwt->lwt_output ? ILA_HOOK_ROUTE_OUTPUT :
287 ILA_HOOK_ROUTE_INPUT))
288 goto nla_put_failure;
289
290 return 0;
291
292 nla_put_failure:
293 return -EMSGSIZE;
294 }
295
ila_encap_nlsize(struct lwtunnel_state * lwtstate)296 static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
297 {
298 return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
299 nla_total_size(sizeof(u8)) + /* ILA_ATTR_CSUM_MODE */
300 nla_total_size(sizeof(u8)) + /* ILA_ATTR_IDENT_TYPE */
301 nla_total_size(sizeof(u8)) + /* ILA_ATTR_HOOK_TYPE */
302 0;
303 }
304
ila_encap_cmp(struct lwtunnel_state * a,struct lwtunnel_state * b)305 static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
306 {
307 struct ila_params *a_p = ila_params_lwtunnel(a);
308 struct ila_params *b_p = ila_params_lwtunnel(b);
309
310 return (a_p->locator.v64 != b_p->locator.v64);
311 }
312
313 static const struct lwtunnel_encap_ops ila_encap_ops = {
314 .build_state = ila_build_state,
315 .destroy_state = ila_destroy_state,
316 .output = ila_output,
317 .input = ila_input,
318 .fill_encap = ila_fill_encap_info,
319 .get_encap_size = ila_encap_nlsize,
320 .cmp_encap = ila_encap_cmp,
321 .owner = THIS_MODULE,
322 };
323
ila_lwt_init(void)324 int ila_lwt_init(void)
325 {
326 return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
327 }
328
ila_lwt_fini(void)329 void ila_lwt_fini(void)
330 {
331 lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
332 }
333