2 * IPV6 GSO/GRO offload support
3 * Linux INET6 implementation
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.
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>
17 #include <net/protocol.h>
19 #include <net/inet_common.h>
21 #include "ip6_offload.h"
23 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
25 const struct net_offload *ops = NULL;
28 struct ipv6_opt_hdr *opth;
31 if (proto != NEXTHDR_HOP) {
32 ops = rcu_dereference(inet6_offloads[proto]);
37 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
41 if (unlikely(!pskb_may_pull(skb, 8)))
44 opth = (void *)skb->data;
45 len = ipv6_optlen(opth);
47 if (unlikely(!pskb_may_pull(skb, len)))
50 opth = (void *)skb->data;
51 proto = opth->nexthdr;
58 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
59 netdev_features_t features)
61 struct sk_buff *segs = ERR_PTR(-EINVAL);
62 struct ipv6hdr *ipv6h;
63 const struct net_offload *ops;
65 struct frag_hdr *fptr;
66 unsigned int unfrag_ip6hlen;
67 unsigned int payload_len;
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))))
78 encap = SKB_GSO_CB(skb)->encap_level > 0;
80 features &= skb->dev->hw_enc_features;
81 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
83 ipv6h = ipv6_hdr(skb);
84 __skb_pull(skb, sizeof(*ipv6h));
85 segs = ERR_PTR(-EPROTONOSUPPORT);
87 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
89 if (skb->encapsulation &&
90 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
91 udpfrag = proto == IPPROTO_UDP && encap;
93 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation;
95 ops = rcu_dereference(inet6_offloads[proto]);
96 if (likely(ops && ops->callbacks.gso_segment)) {
97 skb_reset_transport_header(skb);
98 segs = ops->callbacks.gso_segment(skb, features);
104 for (skb = segs; skb; skb = skb->next) {
105 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
107 payload_len = skb_shinfo(skb)->gso_size +
108 SKB_GSO_CB(skb)->data_offset +
109 skb->head - (unsigned char *)(ipv6h + 1);
111 payload_len = skb->len - nhoff - sizeof(*ipv6h);
112 ipv6h->payload_len = htons(payload_len);
113 skb->network_header = (u8 *)ipv6h - skb->head;
116 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
117 fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen);
118 fptr->frag_off = htons(offset);
120 fptr->frag_off |= htons(IP6_MF);
121 offset += (ntohs(ipv6h->payload_len) -
122 sizeof(struct frag_hdr));
125 skb_reset_inner_headers(skb);
132 /* Return the total length of all the extension hdrs, following the same
133 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
135 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
136 const struct net_offload **opps)
138 struct ipv6_opt_hdr *opth = (void *)iph;
139 int len = 0, proto, optlen = sizeof(*iph);
141 proto = iph->nexthdr;
143 if (proto != NEXTHDR_HOP) {
144 *opps = rcu_dereference(inet6_offloads[proto]);
145 if (unlikely(!(*opps)))
147 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
150 opth = (void *)opth + optlen;
151 optlen = ipv6_optlen(opth);
153 proto = opth->nexthdr;
158 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head,
161 const struct net_offload *ops;
162 struct sk_buff **pp = NULL;
171 off = skb_gro_offset(skb);
172 hlen = off + sizeof(*iph);
173 iph = skb_gro_header_fast(skb, off);
174 if (skb_gro_header_hard(skb, hlen)) {
175 iph = skb_gro_header_slow(skb, hlen, off);
180 skb_set_network_header(skb, off);
181 skb_gro_pull(skb, sizeof(*iph));
182 skb_set_transport_header(skb, skb_gro_offset(skb));
184 flush += ntohs(iph->payload_len) != skb_gro_len(skb);
187 proto = iph->nexthdr;
188 ops = rcu_dereference(inet6_offloads[proto]);
189 if (!ops || !ops->callbacks.gro_receive) {
190 __pskb_pull(skb, skb_gro_offset(skb));
191 proto = ipv6_gso_pull_exthdrs(skb, proto);
192 skb_gro_pull(skb, -skb_transport_offset(skb));
193 skb_reset_transport_header(skb);
194 __skb_push(skb, skb_gro_offset(skb));
196 ops = rcu_dereference(inet6_offloads[proto]);
197 if (!ops || !ops->callbacks.gro_receive)
203 NAPI_GRO_CB(skb)->proto = proto;
206 nlen = skb_network_header_len(skb);
208 for (p = *head; p; p = p->next) {
209 const struct ipv6hdr *iph2;
210 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
212 if (!NAPI_GRO_CB(p)->same_flow)
215 iph2 = (struct ipv6hdr *)(p->data + off);
216 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
218 /* All fields must match except length and Traffic Class.
219 * XXX skbs on the gro_list have all been parsed and pulled
220 * already so we don't need to compare nlen
221 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
222 * memcmp() alone below is suffcient, right?
224 if ((first_word & htonl(0xF00FFFFF)) ||
225 memcmp(&iph->nexthdr, &iph2->nexthdr,
226 nlen - offsetof(struct ipv6hdr, nexthdr))) {
227 NAPI_GRO_CB(p)->same_flow = 0;
230 /* flush if Traffic Class fields are different */
231 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
232 NAPI_GRO_CB(p)->flush |= flush;
234 /* If the previous IP ID value was based on an atomic
235 * datagram we can overwrite the value and ignore it.
237 if (NAPI_GRO_CB(skb)->is_atomic)
238 NAPI_GRO_CB(p)->flush_id = 0;
241 NAPI_GRO_CB(skb)->is_atomic = true;
242 NAPI_GRO_CB(skb)->flush |= flush;
244 skb_gro_postpull_rcsum(skb, iph, nlen);
246 pp = ops->callbacks.gro_receive(head, skb);
252 NAPI_GRO_CB(skb)->flush |= flush;
257 static struct sk_buff **sit_ip6ip6_gro_receive(struct sk_buff **head,
260 /* Common GRO receive for SIT and IP6IP6 */
262 if (NAPI_GRO_CB(skb)->encap_mark) {
263 NAPI_GRO_CB(skb)->flush = 1;
267 NAPI_GRO_CB(skb)->encap_mark = 1;
269 return ipv6_gro_receive(head, skb);
272 static struct sk_buff **ip4ip6_gro_receive(struct sk_buff **head,
275 /* Common GRO receive for SIT and IP6IP6 */
277 if (NAPI_GRO_CB(skb)->encap_mark) {
278 NAPI_GRO_CB(skb)->flush = 1;
282 NAPI_GRO_CB(skb)->encap_mark = 1;
284 return inet_gro_receive(head, skb);
287 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
289 const struct net_offload *ops;
290 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
293 if (skb->encapsulation)
294 skb_set_inner_network_header(skb, nhoff);
296 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
300 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
301 if (WARN_ON(!ops || !ops->callbacks.gro_complete))
304 err = ops->callbacks.gro_complete(skb, nhoff);
312 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
314 skb->encapsulation = 1;
315 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
316 return ipv6_gro_complete(skb, nhoff);
319 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
321 skb->encapsulation = 1;
322 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
323 return ipv6_gro_complete(skb, nhoff);
326 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
328 skb->encapsulation = 1;
329 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
330 return inet_gro_complete(skb, nhoff);
333 static struct packet_offload ipv6_packet_offload __read_mostly = {
334 .type = cpu_to_be16(ETH_P_IPV6),
336 .gso_segment = ipv6_gso_segment,
337 .gro_receive = ipv6_gro_receive,
338 .gro_complete = ipv6_gro_complete,
342 static const struct net_offload sit_offload = {
344 .gso_segment = ipv6_gso_segment,
345 .gro_receive = sit_ip6ip6_gro_receive,
346 .gro_complete = sit_gro_complete,
350 static const struct net_offload ip4ip6_offload = {
352 .gso_segment = inet_gso_segment,
353 .gro_receive = ip4ip6_gro_receive,
354 .gro_complete = ip4ip6_gro_complete,
358 static const struct net_offload ip6ip6_offload = {
360 .gso_segment = ipv6_gso_segment,
361 .gro_receive = sit_ip6ip6_gro_receive,
362 .gro_complete = ip6ip6_gro_complete,
365 static int __init ipv6_offload_init(void)
368 if (tcpv6_offload_init() < 0)
369 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
370 if (ipv6_exthdrs_offload_init() < 0)
371 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
373 dev_add_offload(&ipv6_packet_offload);
375 inet_add_offload(&sit_offload, IPPROTO_IPV6);
376 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
377 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
382 fs_initcall(ipv6_offload_init);