net: use indirect call wrappers at GRO network layer
[muen/linux.git] / net / ipv6 / ip6_offload.c
1 /*
2  *      IPV6 GSO/GRO offload support
3  *      Linux INET6 implementation
4  *
5  *      This program is free software; you can redistribute it and/or
6  *      modify it under the terms of the GNU General Public License
7  *      as published by the Free Software Foundation; either version
8  *      2 of the License, or (at your option) any later version.
9  */
10
11 #include <linux/kernel.h>
12 #include <linux/socket.h>
13 #include <linux/netdevice.h>
14 #include <linux/skbuff.h>
15 #include <linux/printk.h>
16
17 #include <net/protocol.h>
18 #include <net/ipv6.h>
19 #include <net/inet_common.h>
20
21 #include "ip6_offload.h"
22
23 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
24 {
25         const struct net_offload *ops = NULL;
26
27         for (;;) {
28                 struct ipv6_opt_hdr *opth;
29                 int len;
30
31                 if (proto != NEXTHDR_HOP) {
32                         ops = rcu_dereference(inet6_offloads[proto]);
33
34                         if (unlikely(!ops))
35                                 break;
36
37                         if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
38                                 break;
39                 }
40
41                 if (unlikely(!pskb_may_pull(skb, 8)))
42                         break;
43
44                 opth = (void *)skb->data;
45                 len = ipv6_optlen(opth);
46
47                 if (unlikely(!pskb_may_pull(skb, len)))
48                         break;
49
50                 opth = (void *)skb->data;
51                 proto = opth->nexthdr;
52                 __skb_pull(skb, len);
53         }
54
55         return proto;
56 }
57
58 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
59         netdev_features_t features)
60 {
61         struct sk_buff *segs = ERR_PTR(-EINVAL);
62         struct ipv6hdr *ipv6h;
63         const struct net_offload *ops;
64         int proto;
65         struct frag_hdr *fptr;
66         unsigned int payload_len;
67         u8 *prevhdr;
68         int offset = 0;
69         bool encap, udpfrag;
70         int nhoff;
71         bool gso_partial;
72
73         skb_reset_network_header(skb);
74         nhoff = skb_network_header(skb) - skb_mac_header(skb);
75         if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
76                 goto out;
77
78         encap = SKB_GSO_CB(skb)->encap_level > 0;
79         if (encap)
80                 features &= skb->dev->hw_enc_features;
81         SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
82
83         ipv6h = ipv6_hdr(skb);
84         __skb_pull(skb, sizeof(*ipv6h));
85         segs = ERR_PTR(-EPROTONOSUPPORT);
86
87         proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
88
89         if (skb->encapsulation &&
90             skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
91                 udpfrag = proto == IPPROTO_UDP && encap &&
92                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
93         else
94                 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
95                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
96
97         ops = rcu_dereference(inet6_offloads[proto]);
98         if (likely(ops && ops->callbacks.gso_segment)) {
99                 skb_reset_transport_header(skb);
100                 segs = ops->callbacks.gso_segment(skb, features);
101         }
102
103         if (IS_ERR_OR_NULL(segs))
104                 goto out;
105
106         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
107
108         for (skb = segs; skb; skb = skb->next) {
109                 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
110                 if (gso_partial && skb_is_gso(skb))
111                         payload_len = skb_shinfo(skb)->gso_size +
112                                       SKB_GSO_CB(skb)->data_offset +
113                                       skb->head - (unsigned char *)(ipv6h + 1);
114                 else
115                         payload_len = skb->len - nhoff - sizeof(*ipv6h);
116                 ipv6h->payload_len = htons(payload_len);
117                 skb->network_header = (u8 *)ipv6h - skb->head;
118                 skb_reset_mac_len(skb);
119
120                 if (udpfrag) {
121                         int err = ip6_find_1stfragopt(skb, &prevhdr);
122                         if (err < 0) {
123                                 kfree_skb_list(segs);
124                                 return ERR_PTR(err);
125                         }
126                         fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
127                         fptr->frag_off = htons(offset);
128                         if (skb->next)
129                                 fptr->frag_off |= htons(IP6_MF);
130                         offset += (ntohs(ipv6h->payload_len) -
131                                    sizeof(struct frag_hdr));
132                 }
133                 if (encap)
134                         skb_reset_inner_headers(skb);
135         }
136
137 out:
138         return segs;
139 }
140
141 /* Return the total length of all the extension hdrs, following the same
142  * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
143  */
144 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
145                             const struct net_offload **opps)
146 {
147         struct ipv6_opt_hdr *opth = (void *)iph;
148         int len = 0, proto, optlen = sizeof(*iph);
149
150         proto = iph->nexthdr;
151         for (;;) {
152                 if (proto != NEXTHDR_HOP) {
153                         *opps = rcu_dereference(inet6_offloads[proto]);
154                         if (unlikely(!(*opps)))
155                                 break;
156                         if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
157                                 break;
158                 }
159                 opth = (void *)opth + optlen;
160                 optlen = ipv6_optlen(opth);
161                 len += optlen;
162                 proto = opth->nexthdr;
163         }
164         return len;
165 }
166
167 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
168                                                          struct sk_buff *skb)
169 {
170         const struct net_offload *ops;
171         struct sk_buff *pp = NULL;
172         struct sk_buff *p;
173         struct ipv6hdr *iph;
174         unsigned int nlen;
175         unsigned int hlen;
176         unsigned int off;
177         u16 flush = 1;
178         int proto;
179
180         off = skb_gro_offset(skb);
181         hlen = off + sizeof(*iph);
182         iph = skb_gro_header_fast(skb, off);
183         if (skb_gro_header_hard(skb, hlen)) {
184                 iph = skb_gro_header_slow(skb, hlen, off);
185                 if (unlikely(!iph))
186                         goto out;
187         }
188
189         skb_set_network_header(skb, off);
190         skb_gro_pull(skb, sizeof(*iph));
191         skb_set_transport_header(skb, skb_gro_offset(skb));
192
193         flush += ntohs(iph->payload_len) != skb_gro_len(skb);
194
195         rcu_read_lock();
196         proto = iph->nexthdr;
197         ops = rcu_dereference(inet6_offloads[proto]);
198         if (!ops || !ops->callbacks.gro_receive) {
199                 __pskb_pull(skb, skb_gro_offset(skb));
200                 skb_gro_frag0_invalidate(skb);
201                 proto = ipv6_gso_pull_exthdrs(skb, proto);
202                 skb_gro_pull(skb, -skb_transport_offset(skb));
203                 skb_reset_transport_header(skb);
204                 __skb_push(skb, skb_gro_offset(skb));
205
206                 ops = rcu_dereference(inet6_offloads[proto]);
207                 if (!ops || !ops->callbacks.gro_receive)
208                         goto out_unlock;
209
210                 iph = ipv6_hdr(skb);
211         }
212
213         NAPI_GRO_CB(skb)->proto = proto;
214
215         flush--;
216         nlen = skb_network_header_len(skb);
217
218         list_for_each_entry(p, head, list) {
219                 const struct ipv6hdr *iph2;
220                 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
221
222                 if (!NAPI_GRO_CB(p)->same_flow)
223                         continue;
224
225                 iph2 = (struct ipv6hdr *)(p->data + off);
226                 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
227
228                 /* All fields must match except length and Traffic Class.
229                  * XXX skbs on the gro_list have all been parsed and pulled
230                  * already so we don't need to compare nlen
231                  * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
232                  * memcmp() alone below is sufficient, right?
233                  */
234                  if ((first_word & htonl(0xF00FFFFF)) ||
235                     !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
236                     !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
237                     *(u16 *)&iph->nexthdr != *(u16 *)&iph2->nexthdr) {
238 not_same_flow:
239                         NAPI_GRO_CB(p)->same_flow = 0;
240                         continue;
241                 }
242                 if (unlikely(nlen > sizeof(struct ipv6hdr))) {
243                         if (memcmp(iph + 1, iph2 + 1,
244                                    nlen - sizeof(struct ipv6hdr)))
245                                 goto not_same_flow;
246                 }
247                 /* flush if Traffic Class fields are different */
248                 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
249                 NAPI_GRO_CB(p)->flush |= flush;
250
251                 /* If the previous IP ID value was based on an atomic
252                  * datagram we can overwrite the value and ignore it.
253                  */
254                 if (NAPI_GRO_CB(skb)->is_atomic)
255                         NAPI_GRO_CB(p)->flush_id = 0;
256         }
257
258         NAPI_GRO_CB(skb)->is_atomic = true;
259         NAPI_GRO_CB(skb)->flush |= flush;
260
261         skb_gro_postpull_rcsum(skb, iph, nlen);
262
263         pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
264
265 out_unlock:
266         rcu_read_unlock();
267
268 out:
269         skb_gro_flush_final(skb, pp, flush);
270
271         return pp;
272 }
273
274 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
275                                               struct sk_buff *skb)
276 {
277         /* Common GRO receive for SIT and IP6IP6 */
278
279         if (NAPI_GRO_CB(skb)->encap_mark) {
280                 NAPI_GRO_CB(skb)->flush = 1;
281                 return NULL;
282         }
283
284         NAPI_GRO_CB(skb)->encap_mark = 1;
285
286         return ipv6_gro_receive(head, skb);
287 }
288
289 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
290                                           struct sk_buff *skb)
291 {
292         /* Common GRO receive for SIT and IP6IP6 */
293
294         if (NAPI_GRO_CB(skb)->encap_mark) {
295                 NAPI_GRO_CB(skb)->flush = 1;
296                 return NULL;
297         }
298
299         NAPI_GRO_CB(skb)->encap_mark = 1;
300
301         return inet_gro_receive(head, skb);
302 }
303
304 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
305 {
306         const struct net_offload *ops;
307         struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
308         int err = -ENOSYS;
309
310         if (skb->encapsulation) {
311                 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
312                 skb_set_inner_network_header(skb, nhoff);
313         }
314
315         iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
316
317         rcu_read_lock();
318
319         nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
320         if (WARN_ON(!ops || !ops->callbacks.gro_complete))
321                 goto out_unlock;
322
323         err = ops->callbacks.gro_complete(skb, nhoff);
324
325 out_unlock:
326         rcu_read_unlock();
327
328         return err;
329 }
330
331 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
332 {
333         skb->encapsulation = 1;
334         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
335         return ipv6_gro_complete(skb, nhoff);
336 }
337
338 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
339 {
340         skb->encapsulation = 1;
341         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
342         return ipv6_gro_complete(skb, nhoff);
343 }
344
345 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
346 {
347         skb->encapsulation = 1;
348         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
349         return inet_gro_complete(skb, nhoff);
350 }
351
352 static struct packet_offload ipv6_packet_offload __read_mostly = {
353         .type = cpu_to_be16(ETH_P_IPV6),
354         .callbacks = {
355                 .gso_segment = ipv6_gso_segment,
356                 .gro_receive = ipv6_gro_receive,
357                 .gro_complete = ipv6_gro_complete,
358         },
359 };
360
361 static const struct net_offload sit_offload = {
362         .callbacks = {
363                 .gso_segment    = ipv6_gso_segment,
364                 .gro_receive    = sit_ip6ip6_gro_receive,
365                 .gro_complete   = sit_gro_complete,
366         },
367 };
368
369 static const struct net_offload ip4ip6_offload = {
370         .callbacks = {
371                 .gso_segment    = inet_gso_segment,
372                 .gro_receive    = ip4ip6_gro_receive,
373                 .gro_complete   = ip4ip6_gro_complete,
374         },
375 };
376
377 static const struct net_offload ip6ip6_offload = {
378         .callbacks = {
379                 .gso_segment    = ipv6_gso_segment,
380                 .gro_receive    = sit_ip6ip6_gro_receive,
381                 .gro_complete   = ip6ip6_gro_complete,
382         },
383 };
384 static int __init ipv6_offload_init(void)
385 {
386
387         if (tcpv6_offload_init() < 0)
388                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
389         if (ipv6_exthdrs_offload_init() < 0)
390                 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
391
392         dev_add_offload(&ipv6_packet_offload);
393
394         inet_add_offload(&sit_offload, IPPROTO_IPV6);
395         inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
396         inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
397
398         return 0;
399 }
400
401 fs_initcall(ipv6_offload_init);