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
20 #include "ip6_offload.h"
21
22 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
23 {
24 const struct net_offload *ops = NULL;
25
26 for (;;) {
27 struct ipv6_opt_hdr *opth;
28 int len;
29
30 if (proto != NEXTHDR_HOP) {
31 ops = rcu_dereference(inet6_offloads[proto]);
32
33 if (unlikely(!ops))
34 break;
35
36 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
37 break;
38 }
39
40 if (unlikely(!pskb_may_pull(skb, 8)))
41 break;
42
43 opth = (void *)skb->data;
44 len = ipv6_optlen(opth);
45
46 if (unlikely(!pskb_may_pull(skb, len)))
47 break;
48
49 proto = opth->nexthdr;
50 __skb_pull(skb, len);
51 }
52
53 return proto;
54 }
55
56 static int ipv6_gso_send_check(struct sk_buff *skb)
57 {
58 const struct ipv6hdr *ipv6h;
59 const struct net_offload *ops;
60 int err = -EINVAL;
61
62 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
63 goto out;
64
65 ipv6h = ipv6_hdr(skb);
66 __skb_pull(skb, sizeof(*ipv6h));
67 err = -EPROTONOSUPPORT;
68
69 rcu_read_lock();
70 ops = rcu_dereference(inet6_offloads[
71 ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr)]);
72
73 if (likely(ops && ops->callbacks.gso_send_check)) {
74 skb_reset_transport_header(skb);
75 err = ops->callbacks.gso_send_check(skb);
76 }
77 rcu_read_unlock();
78
79 out:
80 return err;
81 }
82
83 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
84 netdev_features_t features)
85 {
86 struct sk_buff *segs = ERR_PTR(-EINVAL);
87 struct ipv6hdr *ipv6h;
88 const struct net_offload *ops;
89 int proto;
90 struct frag_hdr *fptr;
91 unsigned int unfrag_ip6hlen;
92 u8 *prevhdr;
93 int offset = 0;
94
95 if (unlikely(skb_shinfo(skb)->gso_type &
96 ~(SKB_GSO_UDP |
97 SKB_GSO_DODGY |
98 SKB_GSO_TCP_ECN |
99 SKB_GSO_GRE |
100 SKB_GSO_UDP_TUNNEL |
101 SKB_GSO_TCPV6 |
102 0)))
103 goto out;
104
105 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
106 goto out;
107
108 ipv6h = ipv6_hdr(skb);
109 __skb_pull(skb, sizeof(*ipv6h));
110 segs = ERR_PTR(-EPROTONOSUPPORT);
111
112 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
113 rcu_read_lock();
114 ops = rcu_dereference(inet6_offloads[proto]);
115 if (likely(ops && ops->callbacks.gso_segment)) {
116 skb_reset_transport_header(skb);
117 segs = ops->callbacks.gso_segment(skb, features);
118 }
119 rcu_read_unlock();
120
121 if (IS_ERR(segs))
122 goto out;
123
124 for (skb = segs; skb; skb = skb->next) {
125 ipv6h = ipv6_hdr(skb);
126 ipv6h->payload_len = htons(skb->len - skb->mac_len -
127 sizeof(*ipv6h));
128 if (proto == IPPROTO_UDP) {
129 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
130 fptr = (struct frag_hdr *)(skb_network_header(skb) +
131 unfrag_ip6hlen);
132 fptr->frag_off = htons(offset);
133 if (skb->next != NULL)
134 fptr->frag_off |= htons(IP6_MF);
135 offset += (ntohs(ipv6h->payload_len) -
136 sizeof(struct frag_hdr));
137 }
138 }
139
140 out:
141 return segs;
142 }
143
144 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head,
145 struct sk_buff *skb)
146 {
147 const struct net_offload *ops;
148 struct sk_buff **pp = NULL;
149 struct sk_buff *p;
150 struct ipv6hdr *iph;
151 unsigned int nlen;
152 unsigned int hlen;
153 unsigned int off;
154 int flush = 1;
155 int proto;
156 __wsum csum;
157
158 off = skb_gro_offset(skb);
159 hlen = off + sizeof(*iph);
160 iph = skb_gro_header_fast(skb, off);
161 if (skb_gro_header_hard(skb, hlen)) {
162 iph = skb_gro_header_slow(skb, hlen, off);
163 if (unlikely(!iph))
164 goto out;
165 }
166
167 skb_gro_pull(skb, sizeof(*iph));
168 skb_set_transport_header(skb, skb_gro_offset(skb));
169
170 flush += ntohs(iph->payload_len) != skb_gro_len(skb);
171
172 rcu_read_lock();
173 proto = iph->nexthdr;
174 ops = rcu_dereference(inet6_offloads[proto]);
175 if (!ops || !ops->callbacks.gro_receive) {
176 __pskb_pull(skb, skb_gro_offset(skb));
177 skb_gro_frag0_invalidate(skb);
178 proto = ipv6_gso_pull_exthdrs(skb, proto);
179 skb_gro_pull(skb, -skb_transport_offset(skb));
180 skb_reset_transport_header(skb);
181 __skb_push(skb, skb_gro_offset(skb));
182
183 ops = rcu_dereference(inet6_offloads[proto]);
184 if (!ops || !ops->callbacks.gro_receive)
185 goto out_unlock;
186
187 iph = ipv6_hdr(skb);
188 }
189
190 NAPI_GRO_CB(skb)->proto = proto;
191
192 flush--;
193 nlen = skb_network_header_len(skb);
194
195 for (p = *head; p; p = p->next) {
196 const struct ipv6hdr *iph2;
197 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
198
199 if (!NAPI_GRO_CB(p)->same_flow)
200 continue;
201
202 iph2 = ipv6_hdr(p);
203 first_word = *(__be32 *)iph ^ *(__be32 *)iph2 ;
204
205 /* All fields must match except length and Traffic Class. */
206 if (nlen != skb_network_header_len(p) ||
207 (first_word & htonl(0xF00FFFFF)) ||
208 memcmp(&iph->nexthdr, &iph2->nexthdr,
209 nlen - offsetof(struct ipv6hdr, nexthdr))) {
210 NAPI_GRO_CB(p)->same_flow = 0;
211 continue;
212 }
213 /* flush if Traffic Class fields are different */
214 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
215 NAPI_GRO_CB(p)->flush |= flush;
216 }
217
218 NAPI_GRO_CB(skb)->flush |= flush;
219
220 csum = skb->csum;
221 skb_postpull_rcsum(skb, iph, skb_network_header_len(skb));
222
223 pp = ops->callbacks.gro_receive(head, skb);
224
225 skb->csum = csum;
226
227 out_unlock:
228 rcu_read_unlock();
229
230 out:
231 NAPI_GRO_CB(skb)->flush |= flush;
232
233 return pp;
234 }
235
236 static int ipv6_gro_complete(struct sk_buff *skb)
237 {
238 const struct net_offload *ops;
239 struct ipv6hdr *iph = ipv6_hdr(skb);
240 int err = -ENOSYS;
241
242 iph->payload_len = htons(skb->len - skb_network_offset(skb) -
243 sizeof(*iph));
244
245 rcu_read_lock();
246 ops = rcu_dereference(inet6_offloads[NAPI_GRO_CB(skb)->proto]);
247 if (WARN_ON(!ops || !ops->callbacks.gro_complete))
248 goto out_unlock;
249
250 err = ops->callbacks.gro_complete(skb);
251
252 out_unlock:
253 rcu_read_unlock();
254
255 return err;
256 }
257
258 static struct packet_offload ipv6_packet_offload __read_mostly = {
259 .type = cpu_to_be16(ETH_P_IPV6),
260 .callbacks = {
261 .gso_send_check = ipv6_gso_send_check,
262 .gso_segment = ipv6_gso_segment,
263 .gro_receive = ipv6_gro_receive,
264 .gro_complete = ipv6_gro_complete,
265 },
266 };
267
268 static int __init ipv6_offload_init(void)
269 {
270
271 if (tcpv6_offload_init() < 0)
272 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
273 if (udp_offload_init() < 0)
274 pr_crit("%s: Cannot add UDP protocol offload\n", __func__);
275 if (ipv6_exthdrs_offload_init() < 0)
276 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
277
278 dev_add_offload(&ipv6_packet_offload);
279 return 0;
280 }
281
282 fs_initcall(ipv6_offload_init);
283
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