gre_offload.c (438e38fadca2f6e57eeecc08326c8a95758594d4) gre_offload.c (bf5a755f5e9186406bbf50f4087100af5bd68e40)
1/*
2 * IPV4 GSO/GRO offload support
3 * Linux INET 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.

--- 102 unchanged lines hidden (view full) ---

111 skb_set_network_header(skb, mac_len);
112 skb->mac_len = mac_len;
113 skb->protocol = protocol;
114 } while ((skb = skb->next));
115out:
116 return segs;
117}
118
1/*
2 * IPV4 GSO/GRO offload support
3 * Linux INET 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.

--- 102 unchanged lines hidden (view full) ---

111 skb_set_network_header(skb, mac_len);
112 skb->mac_len = mac_len;
113 skb->protocol = protocol;
114 } while ((skb = skb->next));
115out:
116 return segs;
117}
118
119/* Compute the whole skb csum in s/w and store it, then verify GRO csum
120 * starting from gro_offset.
121 */
122static __sum16 gro_skb_checksum(struct sk_buff *skb)
123{
124 __sum16 sum;
125
126 skb->csum = skb_checksum(skb, 0, skb->len, 0);
127 NAPI_GRO_CB(skb)->csum = csum_sub(skb->csum,
128 csum_partial(skb->data, skb_gro_offset(skb), 0));
129 sum = csum_fold(NAPI_GRO_CB(skb)->csum);
130 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) {
131 if (unlikely(!sum))
132 netdev_rx_csum_fault(skb->dev);
133 } else
134 skb->ip_summed = CHECKSUM_COMPLETE;
135
136 return sum;
137}
138
139static struct sk_buff **gre_gro_receive(struct sk_buff **head,
140 struct sk_buff *skb)
141{
142 struct sk_buff **pp = NULL;
143 struct sk_buff *p;
144 const struct gre_base_hdr *greh;
145 unsigned int hlen, grehlen;
146 unsigned int off;
147 int flush = 1;
148 struct packet_offload *ptype;
149 __be16 type;
150
151 off = skb_gro_offset(skb);
152 hlen = off + sizeof(*greh);
153 greh = skb_gro_header_fast(skb, off);
154 if (skb_gro_header_hard(skb, hlen)) {
155 greh = skb_gro_header_slow(skb, hlen, off);
156 if (unlikely(!greh))
157 goto out;
158 }
159
160 /* Only support version 0 and K (key), C (csum) flags. Note that
161 * although the support for the S (seq#) flag can be added easily
162 * for GRO, this is problematic for GSO hence can not be enabled
163 * here because a GRO pkt may end up in the forwarding path, thus
164 * requiring GSO support to break it up correctly.
165 */
166 if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0)
167 goto out;
168
169 type = greh->protocol;
170
171 rcu_read_lock();
172 ptype = gro_find_receive_by_type(type);
173 if (ptype == NULL)
174 goto out_unlock;
175
176 grehlen = GRE_HEADER_SECTION;
177
178 if (greh->flags & GRE_KEY)
179 grehlen += GRE_HEADER_SECTION;
180
181 if (greh->flags & GRE_CSUM)
182 grehlen += GRE_HEADER_SECTION;
183
184 hlen = off + grehlen;
185 if (skb_gro_header_hard(skb, hlen)) {
186 greh = skb_gro_header_slow(skb, hlen, off);
187 if (unlikely(!greh))
188 goto out_unlock;
189 }
190 if (greh->flags & GRE_CSUM) { /* Need to verify GRE csum first */
191 __sum16 csum = 0;
192
193 if (skb->ip_summed == CHECKSUM_COMPLETE)
194 csum = csum_fold(NAPI_GRO_CB(skb)->csum);
195 /* Don't trust csum error calculated/reported by h/w */
196 if (skb->ip_summed == CHECKSUM_NONE || csum != 0)
197 csum = gro_skb_checksum(skb);
198
199 /* GRE CSUM is the 1's complement of the 1's complement sum
200 * of the GRE hdr plus payload so it should add up to 0xffff
201 * (and 0 after csum_fold()) just like the IPv4 hdr csum.
202 */
203 if (csum)
204 goto out_unlock;
205 }
206 flush = 0;
207
208 for (p = *head; p; p = p->next) {
209 const struct gre_base_hdr *greh2;
210
211 if (!NAPI_GRO_CB(p)->same_flow)
212 continue;
213
214 /* The following checks are needed to ensure only pkts
215 * from the same tunnel are considered for aggregation.
216 * The criteria for "the same tunnel" includes:
217 * 1) same version (we only support version 0 here)
218 * 2) same protocol (we only support ETH_P_IP for now)
219 * 3) same set of flags
220 * 4) same key if the key field is present.
221 */
222 greh2 = (struct gre_base_hdr *)(p->data + off);
223
224 if (greh2->flags != greh->flags ||
225 greh2->protocol != greh->protocol) {
226 NAPI_GRO_CB(p)->same_flow = 0;
227 continue;
228 }
229 if (greh->flags & GRE_KEY) {
230 /* compare keys */
231 if (*(__be32 *)(greh2+1) != *(__be32 *)(greh+1)) {
232 NAPI_GRO_CB(p)->same_flow = 0;
233 continue;
234 }
235 }
236 }
237
238 skb_gro_pull(skb, grehlen);
239
240 /* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
241 skb_gro_postpull_rcsum(skb, greh, grehlen);
242
243 pp = ptype->callbacks.gro_receive(head, skb);
244
245out_unlock:
246 rcu_read_unlock();
247out:
248 NAPI_GRO_CB(skb)->flush |= flush;
249
250 return pp;
251}
252
253int gre_gro_complete(struct sk_buff *skb, int nhoff)
254{
255 struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff);
256 struct packet_offload *ptype;
257 unsigned int grehlen = sizeof(*greh);
258 int err = -ENOENT;
259 __be16 type;
260
261 type = greh->protocol;
262 if (greh->flags & GRE_KEY)
263 grehlen += GRE_HEADER_SECTION;
264
265 if (greh->flags & GRE_CSUM)
266 grehlen += GRE_HEADER_SECTION;
267
268 rcu_read_lock();
269 ptype = gro_find_complete_by_type(type);
270 if (ptype != NULL)
271 err = ptype->callbacks.gro_complete(skb, nhoff + grehlen);
272
273 rcu_read_unlock();
274 return err;
275}
276
119static const struct net_offload gre_offload = {
120 .callbacks = {
121 .gso_send_check = gre_gso_send_check,
122 .gso_segment = gre_gso_segment,
277static const struct net_offload gre_offload = {
278 .callbacks = {
279 .gso_send_check = gre_gso_send_check,
280 .gso_segment = gre_gso_segment,
281 .gro_receive = gre_gro_receive,
282 .gro_complete = gre_gro_complete,
123 },
124};
125
126static int __init gre_offload_init(void)
127{
128 return inet_add_offload(&gre_offload, IPPROTO_GRE);
129}
130
131static void __exit gre_offload_exit(void)
132{
133 inet_del_offload(&gre_offload, IPPROTO_GRE);
134}
135
136module_init(gre_offload_init);
137module_exit(gre_offload_exit);
283 },
284};
285
286static int __init gre_offload_init(void)
287{
288 return inet_add_offload(&gre_offload, IPPROTO_GRE);
289}
290
291static void __exit gre_offload_exit(void)
292{
293 inet_del_offload(&gre_offload, IPPROTO_GRE);
294}
295
296module_init(gre_offload_init);
297module_exit(gre_offload_exit);