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 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
51 netdev_features_t features)
53 struct sk_buff *segs = ERR_PTR(-EINVAL);
58 if (skb->encapsulation &&
59 skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) {
60 segs = skb_udp_tunnel_segment(skb, features);
64 mss = skb_shinfo(skb)->gso_size;
65 if (unlikely(skb->len <= mss))
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;
72 if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
75 SKB_GSO_GRE | SKB_GSO_MPLS) ||
76 !(type & (SKB_GSO_UDP))))
79 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
85 /* Do software UFO. Complete and fill in the UDP checksum as
86 * HW cannot do checksum of UDP packets sent as multiple
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;
95 /* Fragment the skb. IP headers of the fragments are updated in
98 segs = skb_segment(skb, features);
103 int udp_add_offload(struct udp_offload *uo)
105 struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC);
110 new_offload->offload = uo;
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);
119 EXPORT_SYMBOL(udp_add_offload);
121 static void udp_offload_free_routine(struct rcu_head *head)
123 struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
127 void udp_del_offload(struct udp_offload *uo)
129 struct udp_offload_priv __rcu **head = &udp_offload_base;
130 struct udp_offload_priv *uo_priv;
132 spin_lock(&udp_offload_lock);
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));
142 head = &uo_priv->next;
144 pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
146 spin_unlock(&udp_offload_lock);
148 call_rcu(&uo_priv->rcu, udp_offload_free_routine);
150 EXPORT_SYMBOL(udp_del_offload);
152 static struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
154 struct udp_offload_priv *uo_priv;
155 struct sk_buff *p, **pp = NULL;
156 struct udphdr *uh, *uh2;
157 unsigned int hlen, off;
160 if (NAPI_GRO_CB(skb)->udp_mark ||
161 (!skb->encapsulation && skb->ip_summed != CHECKSUM_COMPLETE))
164 /* mark that this skb passed once through the udp gro layer */
165 NAPI_GRO_CB(skb)->udp_mark = 1;
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);
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)
188 for (p = *head; p; p = p->next) {
189 if (!NAPI_GRO_CB(p)->same_flow)
192 uh2 = (struct udphdr *)(p->data + off);
193 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
194 NAPI_GRO_CB(p)->same_flow = 0;
199 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
200 pp = uo_priv->offload->callbacks.gro_receive(head, skb);
205 NAPI_GRO_CB(skb)->flush |= flush;
209 static int udp_gro_complete(struct sk_buff *skb, int nhoff)
211 struct udp_offload_priv *uo_priv;
212 __be16 newlen = htons(skb->len - nhoff);
213 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
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)
228 err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr));
234 static const struct net_offload udpv4_offload = {
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,
243 int __init udpv4_offload_init(void)
245 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);