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>
20 #include "ip6_offload.h"
22 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
24 const struct net_offload *ops = NULL;
27 struct ipv6_opt_hdr *opth;
30 if (proto != NEXTHDR_HOP) {
31 ops = rcu_dereference(inet6_offloads[proto]);
36 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
40 if (unlikely(!pskb_may_pull(skb, 8)))
43 opth = (void *)skb->data;
44 len = ipv6_optlen(opth);
46 if (unlikely(!pskb_may_pull(skb, len)))
49 opth = (void *)skb->data;
50 proto = opth->nexthdr;
57 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
58 netdev_features_t features)
60 struct sk_buff *segs = ERR_PTR(-EINVAL);
61 struct ipv6hdr *ipv6h;
62 const struct net_offload *ops;
64 struct frag_hdr *fptr;
65 unsigned int unfrag_ip6hlen;
66 unsigned int payload_len;
72 skb_reset_network_header(skb);
73 nhoff = skb_network_header(skb) - skb_mac_header(skb);
74 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
77 encap = SKB_GSO_CB(skb)->encap_level > 0;
79 features &= skb->dev->hw_enc_features;
80 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
82 ipv6h = ipv6_hdr(skb);
83 __skb_pull(skb, sizeof(*ipv6h));
84 segs = ERR_PTR(-EPROTONOSUPPORT);
86 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
88 if (skb->encapsulation &&
89 skb_shinfo(skb)->gso_type & (SKB_GSO_SIT|SKB_GSO_IPIP))
90 udpfrag = proto == IPPROTO_UDP && encap;
92 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation;
94 ops = rcu_dereference(inet6_offloads[proto]);
95 if (likely(ops && ops->callbacks.gso_segment)) {
96 skb_reset_transport_header(skb);
97 segs = ops->callbacks.gso_segment(skb, features);
103 for (skb = segs; skb; skb = skb->next) {
104 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
106 payload_len = skb_shinfo(skb)->gso_size +
107 SKB_GSO_CB(skb)->data_offset +
108 skb->head - (unsigned char *)(ipv6h + 1);
110 payload_len = skb->len - nhoff - sizeof(*ipv6h);
111 ipv6h->payload_len = htons(payload_len);
112 skb->network_header = (u8 *)ipv6h - skb->head;
115 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
116 fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen);
117 fptr->frag_off = htons(offset);
119 fptr->frag_off |= htons(IP6_MF);
120 offset += (ntohs(ipv6h->payload_len) -
121 sizeof(struct frag_hdr));
124 skb_reset_inner_headers(skb);
131 /* Return the total length of all the extension hdrs, following the same
132 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
134 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
135 const struct net_offload **opps)
137 struct ipv6_opt_hdr *opth = (void *)iph;
138 int len = 0, proto, optlen = sizeof(*iph);
140 proto = iph->nexthdr;
142 if (proto != NEXTHDR_HOP) {
143 *opps = rcu_dereference(inet6_offloads[proto]);
144 if (unlikely(!(*opps)))
146 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
149 opth = (void *)opth + optlen;
150 optlen = ipv6_optlen(opth);
152 proto = opth->nexthdr;
157 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head,
160 const struct net_offload *ops;
161 struct sk_buff **pp = NULL;
170 off = skb_gro_offset(skb);
171 hlen = off + sizeof(*iph);
172 iph = skb_gro_header_fast(skb, off);
173 if (skb_gro_header_hard(skb, hlen)) {
174 iph = skb_gro_header_slow(skb, hlen, off);
179 skb_set_network_header(skb, off);
180 skb_gro_pull(skb, sizeof(*iph));
181 skb_set_transport_header(skb, skb_gro_offset(skb));
183 flush += ntohs(iph->payload_len) != skb_gro_len(skb);
186 proto = iph->nexthdr;
187 ops = rcu_dereference(inet6_offloads[proto]);
188 if (!ops || !ops->callbacks.gro_receive) {
189 __pskb_pull(skb, skb_gro_offset(skb));
190 proto = ipv6_gso_pull_exthdrs(skb, proto);
191 skb_gro_pull(skb, -skb_transport_offset(skb));
192 skb_reset_transport_header(skb);
193 __skb_push(skb, skb_gro_offset(skb));
195 ops = rcu_dereference(inet6_offloads[proto]);
196 if (!ops || !ops->callbacks.gro_receive)
202 NAPI_GRO_CB(skb)->proto = proto;
205 nlen = skb_network_header_len(skb);
207 for (p = *head; p; p = p->next) {
208 const struct ipv6hdr *iph2;
209 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
211 if (!NAPI_GRO_CB(p)->same_flow)
214 iph2 = (struct ipv6hdr *)(p->data + off);
215 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
217 /* All fields must match except length and Traffic Class.
218 * XXX skbs on the gro_list have all been parsed and pulled
219 * already so we don't need to compare nlen
220 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
221 * memcmp() alone below is suffcient, right?
223 if ((first_word & htonl(0xF00FFFFF)) ||
224 memcmp(&iph->nexthdr, &iph2->nexthdr,
225 nlen - offsetof(struct ipv6hdr, nexthdr))) {
226 NAPI_GRO_CB(p)->same_flow = 0;
229 /* flush if Traffic Class fields are different */
230 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
231 NAPI_GRO_CB(p)->flush |= flush;
233 /* If the previous IP ID value was based on an atomic
234 * datagram we can overwrite the value and ignore it.
236 if (NAPI_GRO_CB(skb)->is_atomic)
237 NAPI_GRO_CB(p)->flush_id = 0;
240 NAPI_GRO_CB(skb)->is_atomic = true;
241 NAPI_GRO_CB(skb)->flush |= flush;
243 skb_gro_postpull_rcsum(skb, iph, nlen);
245 pp = ops->callbacks.gro_receive(head, skb);
251 NAPI_GRO_CB(skb)->flush |= flush;
256 static struct sk_buff **sit_gro_receive(struct sk_buff **head,
259 if (NAPI_GRO_CB(skb)->encap_mark) {
260 NAPI_GRO_CB(skb)->flush = 1;
264 NAPI_GRO_CB(skb)->encap_mark = 1;
266 return ipv6_gro_receive(head, skb);
269 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
271 const struct net_offload *ops;
272 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
275 if (skb->encapsulation)
276 skb_set_inner_network_header(skb, nhoff);
278 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
282 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
283 if (WARN_ON(!ops || !ops->callbacks.gro_complete))
286 err = ops->callbacks.gro_complete(skb, nhoff);
294 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
296 skb->encapsulation = 1;
297 skb_shinfo(skb)->gso_type |= SKB_GSO_SIT;
298 return ipv6_gro_complete(skb, nhoff);
301 static struct packet_offload ipv6_packet_offload __read_mostly = {
302 .type = cpu_to_be16(ETH_P_IPV6),
304 .gso_segment = ipv6_gso_segment,
305 .gro_receive = ipv6_gro_receive,
306 .gro_complete = ipv6_gro_complete,
310 static const struct net_offload sit_offload = {
312 .gso_segment = ipv6_gso_segment,
313 .gro_receive = sit_gro_receive,
314 .gro_complete = sit_gro_complete,
318 static int __init ipv6_offload_init(void)
321 if (tcpv6_offload_init() < 0)
322 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
323 if (ipv6_exthdrs_offload_init() < 0)
324 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
326 dev_add_offload(&ipv6_packet_offload);
328 inet_add_offload(&sit_offload, IPPROTO_IPV6);
333 fs_initcall(ipv6_offload_init);