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;
25 struct udp_offload_priv __rcu *next;
28 static int udp4_ufo_send_check(struct sk_buff *skb)
30 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
33 if (likely(!skb->encapsulation)) {
34 const struct iphdr *iph;
40 uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
42 skb->csum_start = skb_transport_header(skb) - skb->head;
43 skb->csum_offset = offsetof(struct udphdr, check);
44 skb->ip_summed = CHECKSUM_PARTIAL;
50 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
51 netdev_features_t features)
53 struct sk_buff *segs = ERR_PTR(-EINVAL);
54 u16 mac_offset = skb->mac_header;
55 int mac_len = skb->mac_len;
56 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
57 __be16 protocol = skb->protocol;
58 netdev_features_t enc_features;
59 int udp_offset, outer_hlen;
63 oldlen = (u16)~skb->len;
65 if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
68 skb->encapsulation = 0;
69 __skb_pull(skb, tnl_hlen);
70 skb_reset_mac_header(skb);
71 skb_set_network_header(skb, skb_inner_network_offset(skb));
72 skb->mac_len = skb_inner_network_offset(skb);
73 skb->protocol = htons(ETH_P_TEB);
75 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
77 skb->encap_hdr_csum = 1;
79 /* segment inner packet. */
80 enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
81 segs = skb_mac_gso_segment(skb, enc_features);
82 if (IS_ERR_OR_NULL(segs)) {
83 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
88 outer_hlen = skb_tnl_header_len(skb);
89 udp_offset = outer_hlen - tnl_hlen;
95 skb_reset_inner_headers(skb);
96 skb->encapsulation = 1;
98 skb->mac_len = mac_len;
100 skb_push(skb, outer_hlen);
101 skb_reset_mac_header(skb);
102 skb_set_network_header(skb, mac_len);
103 skb_set_transport_header(skb, udp_offset);
104 len = skb->len - udp_offset;
106 uh->len = htons(len);
109 __be32 delta = htonl(oldlen + len);
111 uh->check = ~csum_fold((__force __wsum)
112 ((__force u32)uh->check +
113 (__force u32)delta));
114 uh->check = gso_make_checksum(skb, ~uh->check);
117 uh->check = CSUM_MANGLED_0;
120 skb->protocol = protocol;
121 } while ((skb = skb->next));
126 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
127 netdev_features_t features)
129 struct sk_buff *segs = ERR_PTR(-EINVAL);
134 if (skb->encapsulation &&
135 (skb_shinfo(skb)->gso_type &
136 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
137 segs = skb_udp_tunnel_segment(skb, features);
141 mss = skb_shinfo(skb)->gso_size;
142 if (unlikely(skb->len <= mss))
145 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
146 /* Packet is from an untrusted source, reset gso_segs. */
147 int type = skb_shinfo(skb)->gso_type;
149 if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
151 SKB_GSO_UDP_TUNNEL_CSUM |
153 SKB_GSO_GRE | SKB_GSO_GRE_CSUM |
155 !(type & (SKB_GSO_UDP))))
158 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
164 /* Do software UFO. Complete and fill in the UDP checksum as
165 * HW cannot do checksum of UDP packets sent as multiple
168 offset = skb_checksum_start_offset(skb);
169 csum = skb_checksum(skb, offset, skb->len - offset, 0);
170 offset += skb->csum_offset;
171 *(__sum16 *)(skb->data + offset) = csum_fold(csum);
172 skb->ip_summed = CHECKSUM_NONE;
174 /* Fragment the skb. IP headers of the fragments are updated in
177 segs = skb_segment(skb, features);
182 int udp_add_offload(struct udp_offload *uo)
184 struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC);
189 new_offload->offload = uo;
191 spin_lock(&udp_offload_lock);
192 new_offload->next = udp_offload_base;
193 rcu_assign_pointer(udp_offload_base, new_offload);
194 spin_unlock(&udp_offload_lock);
198 EXPORT_SYMBOL(udp_add_offload);
200 static void udp_offload_free_routine(struct rcu_head *head)
202 struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
206 void udp_del_offload(struct udp_offload *uo)
208 struct udp_offload_priv __rcu **head = &udp_offload_base;
209 struct udp_offload_priv *uo_priv;
211 spin_lock(&udp_offload_lock);
213 uo_priv = udp_deref_protected(*head);
214 for (; uo_priv != NULL;
215 uo_priv = udp_deref_protected(*head)) {
216 if (uo_priv->offload == uo) {
217 rcu_assign_pointer(*head,
218 udp_deref_protected(uo_priv->next));
221 head = &uo_priv->next;
223 pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
225 spin_unlock(&udp_offload_lock);
227 call_rcu(&uo_priv->rcu, udp_offload_free_routine);
229 EXPORT_SYMBOL(udp_del_offload);
231 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
234 struct udp_offload_priv *uo_priv;
235 struct sk_buff *p, **pp = NULL;
237 unsigned int off = skb_gro_offset(skb);
240 if (NAPI_GRO_CB(skb)->udp_mark ||
241 (skb->ip_summed != CHECKSUM_PARTIAL &&
242 NAPI_GRO_CB(skb)->csum_cnt == 0 &&
243 !NAPI_GRO_CB(skb)->csum_valid))
246 /* mark that this skb passed once through the udp gro layer */
247 NAPI_GRO_CB(skb)->udp_mark = 1;
250 uo_priv = rcu_dereference(udp_offload_base);
251 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
252 if (uo_priv->offload->port == uh->dest &&
253 uo_priv->offload->callbacks.gro_receive)
261 for (p = *head; p; p = p->next) {
262 if (!NAPI_GRO_CB(p)->same_flow)
265 uh2 = (struct udphdr *)(p->data + off);
267 /* Match ports and either checksums are either both zero
270 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
271 (!uh->check ^ !uh2->check)) {
272 NAPI_GRO_CB(p)->same_flow = 0;
277 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
278 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
279 pp = uo_priv->offload->callbacks.gro_receive(head, skb);
284 NAPI_GRO_CB(skb)->flush |= flush;
288 static struct sk_buff **udp4_gro_receive(struct sk_buff **head,
291 struct udphdr *uh = udp_gro_udphdr(skb);
296 /* Don't bother verifying checksum if we're going to flush anyway. */
297 if (NAPI_GRO_CB(skb)->flush)
300 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
301 inet_gro_compute_pseudo))
304 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
305 inet_gro_compute_pseudo);
307 return udp_gro_receive(head, skb, uh);
310 NAPI_GRO_CB(skb)->flush = 1;
314 int udp_gro_complete(struct sk_buff *skb, int nhoff)
316 struct udp_offload_priv *uo_priv;
317 __be16 newlen = htons(skb->len - nhoff);
318 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
325 uo_priv = rcu_dereference(udp_offload_base);
326 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
327 if (uo_priv->offload->port == uh->dest &&
328 uo_priv->offload->callbacks.gro_complete)
333 err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr));
339 static int udp4_gro_complete(struct sk_buff *skb, int nhoff)
341 const struct iphdr *iph = ip_hdr(skb);
342 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
345 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
348 return udp_gro_complete(skb, nhoff);
351 static const struct net_offload udpv4_offload = {
353 .gso_send_check = udp4_ufo_send_check,
354 .gso_segment = udp4_ufo_fragment,
355 .gro_receive = udp4_gro_receive,
356 .gro_complete = udp4_gro_complete,
360 int __init udpv4_offload_init(void)
362 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);