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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.
9 *
10 * UDPv4 GSO support
11 */
12
13#include <linux/skbuff.h>
14#include <net/udp.h>
15#include <net/protocol.h>
16
17static DEFINE_SPINLOCK(udp_offload_lock);
18static struct udp_offload_priv __rcu *udp_offload_base __read_mostly;
19
20#define udp_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&udp_offload_lock))
21
22struct udp_offload_priv {
23 struct udp_offload *offload;
24 struct rcu_head rcu;
25 struct udp_offload_priv __rcu *next;
26};
27
28static int udp4_ufo_send_check(struct sk_buff *skb)
29{
30 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
31 return -EINVAL;
32
33 if (likely(!skb->encapsulation)) {
34 const struct iphdr *iph;
35 struct udphdr *uh;
36
37 iph = ip_hdr(skb);
38 uh = udp_hdr(skb);
39
40 uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
41 IPPROTO_UDP, 0);
42 skb->csum_start = skb_transport_header(skb) - skb->head;
43 skb->csum_offset = offsetof(struct udphdr, check);
44 skb->ip_summed = CHECKSUM_PARTIAL;
45 }
46
47 return 0;
48}
49
50static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
51 netdev_features_t features)
52{
53 struct sk_buff *segs = ERR_PTR(-EINVAL);
54 unsigned int mss;
55 int offset;
56 __wsum csum;
57
58 if (skb->encapsulation &&
59 skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) {
60 segs = skb_udp_tunnel_segment(skb, features);
61 goto out;
62 }
63
64 mss = skb_shinfo(skb)->gso_size;
65 if (unlikely(skb->len <= mss))
66 goto out;
67
68 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
69 /* Packet is from an untrusted source, reset gso_segs. */
70 int type = skb_shinfo(skb)->gso_type;
71
72 if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
73 SKB_GSO_UDP_TUNNEL |
74 SKB_GSO_IPIP |
75 SKB_GSO_GRE | SKB_GSO_MPLS) ||
76 !(type & (SKB_GSO_UDP))))
77 goto out;
78
79 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
80
81 segs = NULL;
82 goto out;
83 }
84
85 /* Do software UFO. Complete and fill in the UDP checksum as
86 * HW cannot do checksum of UDP packets sent as multiple
87 * IP fragments.
88 */
89 offset = skb_checksum_start_offset(skb);
90 csum = skb_checksum(skb, offset, skb->len - offset, 0);
91 offset += skb->csum_offset;
92 *(__sum16 *)(skb->data + offset) = csum_fold(csum);
93 skb->ip_summed = CHECKSUM_NONE;
94
95 /* Fragment the skb. IP headers of the fragments are updated in
96 * inet_gso_segment()
97 */
98 segs = skb_segment(skb, features);
99out:
100 return segs;
101}
102
103int udp_add_offload(struct udp_offload *uo)
104{
105 struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC);
106
107 if (!new_offload)
108 return -ENOMEM;
109
110 new_offload->offload = uo;
111
112 spin_lock(&udp_offload_lock);
113 new_offload->next = udp_offload_base;
114 rcu_assign_pointer(udp_offload_base, new_offload);
115 spin_unlock(&udp_offload_lock);
116
117 return 0;
118}
119EXPORT_SYMBOL(udp_add_offload);
120
121static void udp_offload_free_routine(struct rcu_head *head)
122{
123 struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
124 kfree(ou_priv);
125}
126
127void udp_del_offload(struct udp_offload *uo)
128{
129 struct udp_offload_priv __rcu **head = &udp_offload_base;
130 struct udp_offload_priv *uo_priv;
131
132 spin_lock(&udp_offload_lock);
133
134 uo_priv = udp_deref_protected(*head);
135 for (; uo_priv != NULL;
136 uo_priv = udp_deref_protected(*head)) {
137 if (uo_priv->offload == uo) {
138 rcu_assign_pointer(*head,
139 udp_deref_protected(uo_priv->next));
140 goto unlock;
141 }
142 head = &uo_priv->next;
143 }
144 pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
145unlock:
146 spin_unlock(&udp_offload_lock);
147 if (uo_priv != NULL)
148 call_rcu(&uo_priv->rcu, udp_offload_free_routine);
149}
150EXPORT_SYMBOL(udp_del_offload);
151
152static struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
153{
154 struct udp_offload_priv *uo_priv;
155 struct sk_buff *p, **pp = NULL;
156 struct udphdr *uh, *uh2;
157 unsigned int hlen, off;
158 int flush = 1;
159
160 if (NAPI_GRO_CB(skb)->udp_mark ||
161 (!skb->encapsulation && skb->ip_summed != CHECKSUM_COMPLETE))
162 goto out;
163
164 /* mark that this skb passed once through the udp gro layer */
165 NAPI_GRO_CB(skb)->udp_mark = 1;
166
167 off = skb_gro_offset(skb);
168 hlen = off + sizeof(*uh);
169 uh = skb_gro_header_fast(skb, off);
170 if (skb_gro_header_hard(skb, hlen)) {
171 uh = skb_gro_header_slow(skb, hlen, off);
172 if (unlikely(!uh))
173 goto out;
174 }
175
176 rcu_read_lock();
177 uo_priv = rcu_dereference(udp_offload_base);
178 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
179 if (uo_priv->offload->port == uh->dest &&
180 uo_priv->offload->callbacks.gro_receive)
181 goto unflush;
182 }
183 goto out_unlock;
184
185unflush:
186 flush = 0;
187
188 for (p = *head; p; p = p->next) {
189 if (!NAPI_GRO_CB(p)->same_flow)
190 continue;
191
192 uh2 = (struct udphdr *)(p->data + off);
193 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
194 NAPI_GRO_CB(p)->same_flow = 0;
195 continue;
196 }
197 }
198
199 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
200 pp = uo_priv->offload->callbacks.gro_receive(head, skb);
201
202out_unlock:
203 rcu_read_unlock();
204out:
205 NAPI_GRO_CB(skb)->flush |= flush;
206 return pp;
207}
208
209static int udp_gro_complete(struct sk_buff *skb, int nhoff)
210{
211 struct udp_offload_priv *uo_priv;
212 __be16 newlen = htons(skb->len - nhoff);
213 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
214 int err = -ENOSYS;
215
216 uh->len = newlen;
217
218 rcu_read_lock();
219
220 uo_priv = rcu_dereference(udp_offload_base);
221 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
222 if (uo_priv->offload->port == uh->dest &&
223 uo_priv->offload->callbacks.gro_complete)
224 break;
225 }
226
227 if (uo_priv != NULL)
228 err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr));
229
230 rcu_read_unlock();
231 return err;
232}
233
234static const struct net_offload udpv4_offload = {
235 .callbacks = {
236 .gso_send_check = udp4_ufo_send_check,
237 .gso_segment = udp4_ufo_fragment,
238 .gro_receive = udp_gro_receive,
239 .gro_complete = udp_gro_complete,
240 },
241};
242
243int __init udpv4_offload_init(void)
244{
245 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
246}
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.
9 *
10 * UDPv4 GSO support
11 */
12
13#include <linux/skbuff.h>
14#include <net/udp.h>
15#include <net/protocol.h>
16
17static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
18 netdev_features_t features,
19 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
20 netdev_features_t features),
21 __be16 new_protocol, bool is_ipv6)
22{
23 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
24 bool remcsum, need_csum, offload_csum, gso_partial;
25 struct sk_buff *segs = ERR_PTR(-EINVAL);
26 struct udphdr *uh = udp_hdr(skb);
27 u16 mac_offset = skb->mac_header;
28 __be16 protocol = skb->protocol;
29 u16 mac_len = skb->mac_len;
30 int udp_offset, outer_hlen;
31 __wsum partial;
32 bool need_ipsec;
33
34 if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
35 goto out;
36
37 /* Adjust partial header checksum to negate old length.
38 * We cannot rely on the value contained in uh->len as it is
39 * possible that the actual value exceeds the boundaries of the
40 * 16 bit length field due to the header being added outside of an
41 * IP or IPv6 frame that was already limited to 64K - 1.
42 */
43 if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
44 partial = (__force __wsum)uh->len;
45 else
46 partial = (__force __wsum)htonl(skb->len);
47 partial = csum_sub(csum_unfold(uh->check), partial);
48
49 /* setup inner skb. */
50 skb->encapsulation = 0;
51 SKB_GSO_CB(skb)->encap_level = 0;
52 __skb_pull(skb, tnl_hlen);
53 skb_reset_mac_header(skb);
54 skb_set_network_header(skb, skb_inner_network_offset(skb));
55 skb->mac_len = skb_inner_network_offset(skb);
56 skb->protocol = new_protocol;
57
58 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
59 skb->encap_hdr_csum = need_csum;
60
61 remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
62 skb->remcsum_offload = remcsum;
63
64 need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
65 /* Try to offload checksum if possible */
66 offload_csum = !!(need_csum &&
67 !need_ipsec &&
68 (skb->dev->features &
69 (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
70 (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
71
72 features &= skb->dev->hw_enc_features;
73
74 /* The only checksum offload we care about from here on out is the
75 * outer one so strip the existing checksum feature flags and
76 * instead set the flag based on our outer checksum offload value.
77 */
78 if (remcsum) {
79 features &= ~NETIF_F_CSUM_MASK;
80 if (!need_csum || offload_csum)
81 features |= NETIF_F_HW_CSUM;
82 }
83
84 /* segment inner packet. */
85 segs = gso_inner_segment(skb, features);
86 if (IS_ERR_OR_NULL(segs)) {
87 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
88 mac_len);
89 goto out;
90 }
91
92 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
93
94 outer_hlen = skb_tnl_header_len(skb);
95 udp_offset = outer_hlen - tnl_hlen;
96 skb = segs;
97 do {
98 unsigned int len;
99
100 if (remcsum)
101 skb->ip_summed = CHECKSUM_NONE;
102
103 /* Set up inner headers if we are offloading inner checksum */
104 if (skb->ip_summed == CHECKSUM_PARTIAL) {
105 skb_reset_inner_headers(skb);
106 skb->encapsulation = 1;
107 }
108
109 skb->mac_len = mac_len;
110 skb->protocol = protocol;
111
112 __skb_push(skb, outer_hlen);
113 skb_reset_mac_header(skb);
114 skb_set_network_header(skb, mac_len);
115 skb_set_transport_header(skb, udp_offset);
116 len = skb->len - udp_offset;
117 uh = udp_hdr(skb);
118
119 /* If we are only performing partial GSO the inner header
120 * will be using a length value equal to only one MSS sized
121 * segment instead of the entire frame.
122 */
123 if (gso_partial && skb_is_gso(skb)) {
124 uh->len = htons(skb_shinfo(skb)->gso_size +
125 SKB_GSO_CB(skb)->data_offset +
126 skb->head - (unsigned char *)uh);
127 } else {
128 uh->len = htons(len);
129 }
130
131 if (!need_csum)
132 continue;
133
134 uh->check = ~csum_fold(csum_add(partial,
135 (__force __wsum)htonl(len)));
136
137 if (skb->encapsulation || !offload_csum) {
138 uh->check = gso_make_checksum(skb, ~uh->check);
139 if (uh->check == 0)
140 uh->check = CSUM_MANGLED_0;
141 } else {
142 skb->ip_summed = CHECKSUM_PARTIAL;
143 skb->csum_start = skb_transport_header(skb) - skb->head;
144 skb->csum_offset = offsetof(struct udphdr, check);
145 }
146 } while ((skb = skb->next));
147out:
148 return segs;
149}
150
151struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
152 netdev_features_t features,
153 bool is_ipv6)
154{
155 __be16 protocol = skb->protocol;
156 const struct net_offload **offloads;
157 const struct net_offload *ops;
158 struct sk_buff *segs = ERR_PTR(-EINVAL);
159 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
160 netdev_features_t features);
161
162 rcu_read_lock();
163
164 switch (skb->inner_protocol_type) {
165 case ENCAP_TYPE_ETHER:
166 protocol = skb->inner_protocol;
167 gso_inner_segment = skb_mac_gso_segment;
168 break;
169 case ENCAP_TYPE_IPPROTO:
170 offloads = is_ipv6 ? inet6_offloads : inet_offloads;
171 ops = rcu_dereference(offloads[skb->inner_ipproto]);
172 if (!ops || !ops->callbacks.gso_segment)
173 goto out_unlock;
174 gso_inner_segment = ops->callbacks.gso_segment;
175 break;
176 default:
177 goto out_unlock;
178 }
179
180 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
181 protocol, is_ipv6);
182
183out_unlock:
184 rcu_read_unlock();
185
186 return segs;
187}
188EXPORT_SYMBOL(skb_udp_tunnel_segment);
189
190static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
191 netdev_features_t features)
192{
193 struct sk_buff *segs = ERR_PTR(-EINVAL);
194 unsigned int mss;
195 __wsum csum;
196 struct udphdr *uh;
197 struct iphdr *iph;
198
199 if (skb->encapsulation &&
200 (skb_shinfo(skb)->gso_type &
201 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
202 segs = skb_udp_tunnel_segment(skb, features, false);
203 goto out;
204 }
205
206 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
207 goto out;
208
209 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
210 goto out;
211
212 mss = skb_shinfo(skb)->gso_size;
213 if (unlikely(skb->len <= mss))
214 goto out;
215
216 /* Do software UFO. Complete and fill in the UDP checksum as
217 * HW cannot do checksum of UDP packets sent as multiple
218 * IP fragments.
219 */
220
221 uh = udp_hdr(skb);
222 iph = ip_hdr(skb);
223
224 uh->check = 0;
225 csum = skb_checksum(skb, 0, skb->len, 0);
226 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
227 if (uh->check == 0)
228 uh->check = CSUM_MANGLED_0;
229
230 skb->ip_summed = CHECKSUM_UNNECESSARY;
231
232 /* If there is no outer header we can fake a checksum offload
233 * due to the fact that we have already done the checksum in
234 * software prior to segmenting the frame.
235 */
236 if (!skb->encap_hdr_csum)
237 features |= NETIF_F_HW_CSUM;
238
239 /* Fragment the skb. IP headers of the fragments are updated in
240 * inet_gso_segment()
241 */
242 segs = skb_segment(skb, features);
243out:
244 return segs;
245}
246
247struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
248 struct udphdr *uh, udp_lookup_t lookup)
249{
250 struct sk_buff *p, **pp = NULL;
251 struct udphdr *uh2;
252 unsigned int off = skb_gro_offset(skb);
253 int flush = 1;
254 struct sock *sk;
255
256 if (NAPI_GRO_CB(skb)->encap_mark ||
257 (skb->ip_summed != CHECKSUM_PARTIAL &&
258 NAPI_GRO_CB(skb)->csum_cnt == 0 &&
259 !NAPI_GRO_CB(skb)->csum_valid))
260 goto out;
261
262 /* mark that this skb passed once through the tunnel gro layer */
263 NAPI_GRO_CB(skb)->encap_mark = 1;
264
265 rcu_read_lock();
266 sk = (*lookup)(skb, uh->source, uh->dest);
267
268 if (sk && udp_sk(sk)->gro_receive)
269 goto unflush;
270 goto out_unlock;
271
272unflush:
273 flush = 0;
274
275 for (p = *head; p; p = p->next) {
276 if (!NAPI_GRO_CB(p)->same_flow)
277 continue;
278
279 uh2 = (struct udphdr *)(p->data + off);
280
281 /* Match ports and either checksums are either both zero
282 * or nonzero.
283 */
284 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
285 (!uh->check ^ !uh2->check)) {
286 NAPI_GRO_CB(p)->same_flow = 0;
287 continue;
288 }
289 }
290
291 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
292 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
293 pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
294
295out_unlock:
296 rcu_read_unlock();
297out:
298 NAPI_GRO_CB(skb)->flush |= flush;
299 return pp;
300}
301EXPORT_SYMBOL(udp_gro_receive);
302
303static struct sk_buff **udp4_gro_receive(struct sk_buff **head,
304 struct sk_buff *skb)
305{
306 struct udphdr *uh = udp_gro_udphdr(skb);
307
308 if (unlikely(!uh))
309 goto flush;
310
311 /* Don't bother verifying checksum if we're going to flush anyway. */
312 if (NAPI_GRO_CB(skb)->flush)
313 goto skip;
314
315 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
316 inet_gro_compute_pseudo))
317 goto flush;
318 else if (uh->check)
319 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
320 inet_gro_compute_pseudo);
321skip:
322 NAPI_GRO_CB(skb)->is_ipv6 = 0;
323 return udp_gro_receive(head, skb, uh, udp4_lib_lookup_skb);
324
325flush:
326 NAPI_GRO_CB(skb)->flush = 1;
327 return NULL;
328}
329
330int udp_gro_complete(struct sk_buff *skb, int nhoff,
331 udp_lookup_t lookup)
332{
333 __be16 newlen = htons(skb->len - nhoff);
334 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
335 int err = -ENOSYS;
336 struct sock *sk;
337
338 uh->len = newlen;
339
340 /* Set encapsulation before calling into inner gro_complete() functions
341 * to make them set up the inner offsets.
342 */
343 skb->encapsulation = 1;
344
345 rcu_read_lock();
346 sk = (*lookup)(skb, uh->source, uh->dest);
347 if (sk && udp_sk(sk)->gro_complete)
348 err = udp_sk(sk)->gro_complete(sk, skb,
349 nhoff + sizeof(struct udphdr));
350 rcu_read_unlock();
351
352 if (skb->remcsum_offload)
353 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
354
355 return err;
356}
357EXPORT_SYMBOL(udp_gro_complete);
358
359static int udp4_gro_complete(struct sk_buff *skb, int nhoff)
360{
361 const struct iphdr *iph = ip_hdr(skb);
362 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
363
364 if (uh->check) {
365 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
366 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
367 iph->daddr, 0);
368 } else {
369 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
370 }
371
372 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
373}
374
375static const struct net_offload udpv4_offload = {
376 .callbacks = {
377 .gso_segment = udp4_ufo_fragment,
378 .gro_receive = udp4_gro_receive,
379 .gro_complete = udp4_gro_complete,
380 },
381};
382
383int __init udpv4_offload_init(void)
384{
385 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
386}