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 struct udp_offload_priv {
21 struct udp_offload *offload;
23 struct udp_offload_priv __rcu *next;
26 static int udp4_ufo_send_check(struct sk_buff *skb)
28 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
31 if (likely(!skb->encapsulation)) {
32 const struct iphdr *iph;
38 uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
40 skb->csum_start = skb_transport_header(skb) - skb->head;
41 skb->csum_offset = offsetof(struct udphdr, check);
42 skb->ip_summed = CHECKSUM_PARTIAL;
48 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
49 netdev_features_t features)
51 struct sk_buff *segs = ERR_PTR(-EINVAL);
56 if (skb->encapsulation &&
57 skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) {
58 segs = skb_udp_tunnel_segment(skb, features);
62 mss = skb_shinfo(skb)->gso_size;
63 if (unlikely(skb->len <= mss))
66 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
67 /* Packet is from an untrusted source, reset gso_segs. */
68 int type = skb_shinfo(skb)->gso_type;
70 if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
73 SKB_GSO_GRE | SKB_GSO_MPLS) ||
74 !(type & (SKB_GSO_UDP))))
77 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
83 /* Do software UFO. Complete and fill in the UDP checksum as
84 * HW cannot do checksum of UDP packets sent as multiple
87 offset = skb_checksum_start_offset(skb);
88 csum = skb_checksum(skb, offset, skb->len - offset, 0);
89 offset += skb->csum_offset;
90 *(__sum16 *)(skb->data + offset) = csum_fold(csum);
91 skb->ip_summed = CHECKSUM_NONE;
93 /* Fragment the skb. IP headers of the fragments are updated in
96 segs = skb_segment(skb, features);
101 int udp_add_offload(struct udp_offload *uo)
103 struct udp_offload_priv __rcu **head = &udp_offload_base;
104 struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_KERNEL);
109 new_offload->offload = uo;
111 spin_lock(&udp_offload_lock);
112 rcu_assign_pointer(new_offload->next, rcu_dereference(*head));
113 rcu_assign_pointer(*head, new_offload);
114 spin_unlock(&udp_offload_lock);
118 EXPORT_SYMBOL(udp_add_offload);
120 static void udp_offload_free_routine(struct rcu_head *head)
122 struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
126 void udp_del_offload(struct udp_offload *uo)
128 struct udp_offload_priv __rcu **head = &udp_offload_base;
129 struct udp_offload_priv *uo_priv;
131 spin_lock(&udp_offload_lock);
133 uo_priv = rcu_dereference(*head);
134 for (; uo_priv != NULL;
135 uo_priv = rcu_dereference(*head)) {
137 if (uo_priv->offload == uo) {
138 rcu_assign_pointer(*head, rcu_dereference(uo_priv->next));
141 head = &uo_priv->next;
143 pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
145 spin_unlock(&udp_offload_lock);
147 call_rcu(&uo_priv->rcu, udp_offload_free_routine);
149 EXPORT_SYMBOL(udp_del_offload);
151 static struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
153 struct udp_offload_priv *uo_priv;
154 struct sk_buff *p, **pp = NULL;
155 struct udphdr *uh, *uh2;
156 unsigned int hlen, off;
159 if (NAPI_GRO_CB(skb)->udp_mark ||
160 (!skb->encapsulation && skb->ip_summed != CHECKSUM_COMPLETE))
163 /* mark that this skb passed once through the udp gro layer */
164 NAPI_GRO_CB(skb)->udp_mark = 1;
166 off = skb_gro_offset(skb);
167 hlen = off + sizeof(*uh);
168 uh = skb_gro_header_fast(skb, off);
169 if (skb_gro_header_hard(skb, hlen)) {
170 uh = skb_gro_header_slow(skb, hlen, off);
176 uo_priv = rcu_dereference(udp_offload_base);
177 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
178 if (uo_priv->offload->port == uh->dest &&
179 uo_priv->offload->callbacks.gro_receive)
187 for (p = *head; p; p = p->next) {
188 if (!NAPI_GRO_CB(p)->same_flow)
191 uh2 = (struct udphdr *)(p->data + off);
192 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
193 NAPI_GRO_CB(p)->same_flow = 0;
198 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
199 pp = uo_priv->offload->callbacks.gro_receive(head, skb);
204 NAPI_GRO_CB(skb)->flush |= flush;
208 static int udp_gro_complete(struct sk_buff *skb, int nhoff)
210 struct udp_offload_priv *uo_priv;
211 __be16 newlen = htons(skb->len - nhoff);
212 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
219 uo_priv = rcu_dereference(udp_offload_base);
220 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
221 if (uo_priv->offload->port == uh->dest &&
222 uo_priv->offload->callbacks.gro_complete)
227 err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr));
233 static const struct net_offload udpv4_offload = {
235 .gso_send_check = udp4_ufo_send_check,
236 .gso_segment = udp4_ufo_fragment,
237 .gro_receive = udp_gro_receive,
238 .gro_complete = udp_gro_complete,
242 int __init udpv4_offload_init(void)
244 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);