blob: f35eccaa855ebfbac508503c9111311d6728f8ff [file] [log] [blame]
Daniel Borkmannda5bab02013-06-08 12:56:03 +02001/*
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 int udp4_ufo_send_check(struct sk_buff *skb)
18{
19 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
20 return -EINVAL;
21
22 if (likely(!skb->encapsulation)) {
23 const struct iphdr *iph;
24 struct udphdr *uh;
25
26 iph = ip_hdr(skb);
27 uh = udp_hdr(skb);
28
29 uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
30 IPPROTO_UDP, 0);
31 skb->csum_start = skb_transport_header(skb) - skb->head;
32 skb->csum_offset = offsetof(struct udphdr, check);
33 skb->ip_summed = CHECKSUM_PARTIAL;
34 }
35
36 return 0;
37}
38
39static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
40 netdev_features_t features)
41{
42 struct sk_buff *segs = ERR_PTR(-EINVAL);
43 unsigned int mss;
44
45 mss = skb_shinfo(skb)->gso_size;
46 if (unlikely(skb->len <= mss))
47 goto out;
48
49 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
50 /* Packet is from an untrusted source, reset gso_segs. */
51 int type = skb_shinfo(skb)->gso_type;
52
53 if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
54 SKB_GSO_UDP_TUNNEL |
55 SKB_GSO_GRE | SKB_GSO_MPLS) ||
56 !(type & (SKB_GSO_UDP))))
57 goto out;
58
59 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
60
61 segs = NULL;
62 goto out;
63 }
64
65 /* Fragment the skb. IP headers of the fragments are updated in
66 * inet_gso_segment()
67 */
68 if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
69 segs = skb_udp_tunnel_segment(skb, features);
70 else {
71 int offset;
72 __wsum csum;
73
74 /* Do software UFO. Complete and fill in the UDP checksum as
75 * HW cannot do checksum of UDP packets sent as multiple
76 * IP fragments.
77 */
78 offset = skb_checksum_start_offset(skb);
79 csum = skb_checksum(skb, offset, skb->len - offset, 0);
80 offset += skb->csum_offset;
81 *(__sum16 *)(skb->data + offset) = csum_fold(csum);
82 skb->ip_summed = CHECKSUM_NONE;
83
84 segs = skb_segment(skb, features);
85 }
86out:
87 return segs;
88}
89
90static const struct net_offload udpv4_offload = {
91 .callbacks = {
92 .gso_send_check = udp4_ufo_send_check,
93 .gso_segment = udp4_ufo_fragment,
94 },
95};
96
97int __init udpv4_offload_init(void)
98{
99 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
100}