2 * IPV4 GSO/GRO offload support
3 * Linux INET 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.
13 #include <linux/skbuff.h>
15 #include <net/protocol.h>
17 static DEFINE_SPINLOCK(udp_offload_lock);
18 static struct udp_offload_priv __rcu *udp_offload_base __read_mostly;
20 #define udp_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&udp_offload_lock))
22 struct udp_offload_priv {
23 struct udp_offload *offload;
26 struct udp_offload_priv __rcu *next;
29 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
30 netdev_features_t features,
31 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
32 netdev_features_t features),
33 __be16 new_protocol, bool is_ipv6)
35 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
36 bool remcsum, need_csum, offload_csum, ufo;
37 struct sk_buff *segs = ERR_PTR(-EINVAL);
38 struct udphdr *uh = udp_hdr(skb);
39 u16 mac_offset = skb->mac_header;
40 __be16 protocol = skb->protocol;
41 u16 mac_len = skb->mac_len;
42 int udp_offset, outer_hlen;
45 if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
48 /* Adjust partial header checksum to negate old length.
49 * We cannot rely on the value contained in uh->len as it is
50 * possible that the actual value exceeds the boundaries of the
51 * 16 bit length field due to the header being added outside of an
52 * IP or IPv6 frame that was already limited to 64K - 1.
54 partial = csum_sub(csum_unfold(uh->check),
55 (__force __wsum)htonl(skb->len));
57 /* setup inner skb. */
58 skb->encapsulation = 0;
59 SKB_GSO_CB(skb)->encap_level = 0;
60 __skb_pull(skb, tnl_hlen);
61 skb_reset_mac_header(skb);
62 skb_set_network_header(skb, skb_inner_network_offset(skb));
63 skb->mac_len = skb_inner_network_offset(skb);
64 skb->protocol = new_protocol;
66 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
67 skb->encap_hdr_csum = need_csum;
69 remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
70 skb->remcsum_offload = remcsum;
72 ufo = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
74 /* Try to offload checksum if possible */
75 offload_csum = !!(need_csum &&
77 (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
78 (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
80 features &= skb->dev->hw_enc_features;
82 /* The only checksum offload we care about from here on out is the
83 * outer one so strip the existing checksum feature flags and
84 * instead set the flag based on our outer checksum offload value.
87 features &= ~NETIF_F_CSUM_MASK;
88 if (!need_csum || offload_csum)
89 features |= NETIF_F_HW_CSUM;
92 /* segment inner packet. */
93 segs = gso_inner_segment(skb, features);
94 if (IS_ERR_OR_NULL(segs)) {
95 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
100 outer_hlen = skb_tnl_header_len(skb);
101 udp_offset = outer_hlen - tnl_hlen;
107 skb->ip_summed = CHECKSUM_NONE;
109 /* Set up inner headers if we are offloading inner checksum */
110 if (skb->ip_summed == CHECKSUM_PARTIAL) {
111 skb_reset_inner_headers(skb);
112 skb->encapsulation = 1;
115 skb->mac_len = mac_len;
116 skb->protocol = protocol;
118 __skb_push(skb, outer_hlen);
119 skb_reset_mac_header(skb);
120 skb_set_network_header(skb, mac_len);
121 skb_set_transport_header(skb, udp_offset);
122 len = htons(skb->len - udp_offset);
129 uh->check = ~csum_fold(csum_add(partial, (__force __wsum)len));
131 if (skb->encapsulation || !offload_csum) {
132 uh->check = gso_make_checksum(skb, ~uh->check);
134 uh->check = CSUM_MANGLED_0;
136 skb->ip_summed = CHECKSUM_PARTIAL;
137 skb->csum_start = skb_transport_header(skb) - skb->head;
138 skb->csum_offset = offsetof(struct udphdr, check);
140 } while ((skb = skb->next));
145 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
146 netdev_features_t features,
149 __be16 protocol = skb->protocol;
150 const struct net_offload **offloads;
151 const struct net_offload *ops;
152 struct sk_buff *segs = ERR_PTR(-EINVAL);
153 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
154 netdev_features_t features);
158 switch (skb->inner_protocol_type) {
159 case ENCAP_TYPE_ETHER:
160 protocol = skb->inner_protocol;
161 gso_inner_segment = skb_mac_gso_segment;
163 case ENCAP_TYPE_IPPROTO:
164 offloads = is_ipv6 ? inet6_offloads : inet_offloads;
165 ops = rcu_dereference(offloads[skb->inner_ipproto]);
166 if (!ops || !ops->callbacks.gso_segment)
168 gso_inner_segment = ops->callbacks.gso_segment;
174 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
182 EXPORT_SYMBOL(skb_udp_tunnel_segment);
184 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
185 netdev_features_t features)
187 struct sk_buff *segs = ERR_PTR(-EINVAL);
193 if (skb->encapsulation &&
194 (skb_shinfo(skb)->gso_type &
195 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
196 segs = skb_udp_tunnel_segment(skb, features, false);
200 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
203 mss = skb_shinfo(skb)->gso_size;
204 if (unlikely(skb->len <= mss))
207 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
208 /* Packet is from an untrusted source, reset gso_segs. */
209 int type = skb_shinfo(skb)->gso_type;
211 if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
213 SKB_GSO_UDP_TUNNEL_CSUM |
214 SKB_GSO_TUNNEL_REMCSUM |
216 SKB_GSO_GRE | SKB_GSO_GRE_CSUM) ||
217 !(type & (SKB_GSO_UDP))))
220 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
226 /* Do software UFO. Complete and fill in the UDP checksum as
227 * HW cannot do checksum of UDP packets sent as multiple
235 csum = skb_checksum(skb, 0, skb->len, 0);
236 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
238 uh->check = CSUM_MANGLED_0;
240 skb->ip_summed = CHECKSUM_NONE;
242 /* If there is no outer header we can fake a checksum offload
243 * due to the fact that we have already done the checksum in
244 * software prior to segmenting the frame.
246 if (!skb->encap_hdr_csum)
247 features |= NETIF_F_HW_CSUM;
249 /* Fragment the skb. IP headers of the fragments are updated in
252 segs = skb_segment(skb, features);
257 int udp_add_offload(struct net *net, struct udp_offload *uo)
259 struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC);
264 write_pnet(&new_offload->net, net);
265 new_offload->offload = uo;
267 spin_lock(&udp_offload_lock);
268 new_offload->next = udp_offload_base;
269 rcu_assign_pointer(udp_offload_base, new_offload);
270 spin_unlock(&udp_offload_lock);
274 EXPORT_SYMBOL(udp_add_offload);
276 static void udp_offload_free_routine(struct rcu_head *head)
278 struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
282 void udp_del_offload(struct udp_offload *uo)
284 struct udp_offload_priv __rcu **head = &udp_offload_base;
285 struct udp_offload_priv *uo_priv;
287 spin_lock(&udp_offload_lock);
289 uo_priv = udp_deref_protected(*head);
290 for (; uo_priv != NULL;
291 uo_priv = udp_deref_protected(*head)) {
292 if (uo_priv->offload == uo) {
293 rcu_assign_pointer(*head,
294 udp_deref_protected(uo_priv->next));
297 head = &uo_priv->next;
299 pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
301 spin_unlock(&udp_offload_lock);
303 call_rcu(&uo_priv->rcu, udp_offload_free_routine);
305 EXPORT_SYMBOL(udp_del_offload);
307 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
308 struct udphdr *uh, udp_lookup_t lookup)
310 struct sk_buff *p, **pp = NULL;
312 unsigned int off = skb_gro_offset(skb);
316 if (NAPI_GRO_CB(skb)->encap_mark ||
317 (skb->ip_summed != CHECKSUM_PARTIAL &&
318 NAPI_GRO_CB(skb)->csum_cnt == 0 &&
319 !NAPI_GRO_CB(skb)->csum_valid))
322 /* mark that this skb passed once through the tunnel gro layer */
323 NAPI_GRO_CB(skb)->encap_mark = 1;
326 sk = (*lookup)(skb, uh->source, uh->dest);
328 if (sk && udp_sk(sk)->gro_receive)
336 for (p = *head; p; p = p->next) {
337 if (!NAPI_GRO_CB(p)->same_flow)
340 uh2 = (struct udphdr *)(p->data + off);
342 /* Match ports and either checksums are either both zero
345 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
346 (!uh->check ^ !uh2->check)) {
347 NAPI_GRO_CB(p)->same_flow = 0;
352 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
353 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
354 pp = udp_sk(sk)->gro_receive(sk, head, skb);
359 NAPI_GRO_CB(skb)->flush |= flush;
362 EXPORT_SYMBOL(udp_gro_receive);
364 static struct sk_buff **udp4_gro_receive(struct sk_buff **head,
367 struct udphdr *uh = udp_gro_udphdr(skb);
372 /* Don't bother verifying checksum if we're going to flush anyway. */
373 if (NAPI_GRO_CB(skb)->flush)
376 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
377 inet_gro_compute_pseudo))
380 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
381 inet_gro_compute_pseudo);
383 NAPI_GRO_CB(skb)->is_ipv6 = 0;
384 return udp_gro_receive(head, skb, uh, udp4_lib_lookup_skb);
387 NAPI_GRO_CB(skb)->flush = 1;
391 int udp_gro_complete(struct sk_buff *skb, int nhoff,
394 __be16 newlen = htons(skb->len - nhoff);
395 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
402 sk = (*lookup)(skb, uh->source, uh->dest);
403 if (sk && udp_sk(sk)->gro_complete)
404 err = udp_sk(sk)->gro_complete(sk, skb,
405 nhoff + sizeof(struct udphdr));
408 if (skb->remcsum_offload)
409 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
411 skb->encapsulation = 1;
412 skb_set_inner_mac_header(skb, nhoff + sizeof(struct udphdr));
416 EXPORT_SYMBOL(udp_gro_complete);
418 static int udp4_gro_complete(struct sk_buff *skb, int nhoff)
420 const struct iphdr *iph = ip_hdr(skb);
421 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
424 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
425 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
428 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
431 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
434 static const struct net_offload udpv4_offload = {
436 .gso_segment = udp4_ufo_fragment,
437 .gro_receive = udp4_gro_receive,
438 .gro_complete = udp4_gro_complete,
442 int __init udpv4_offload_init(void)
444 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);