blob: 83206de2bc7679dc20e4fdcf34f8b1f5cd7831ef [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 |
Eric Dumazetcb32f512013-10-19 11:42:57 -070055 SKB_GSO_IPIP |
Daniel Borkmannda5bab02013-06-08 12:56:03 +020056 SKB_GSO_GRE | SKB_GSO_MPLS) ||
57 !(type & (SKB_GSO_UDP))))
58 goto out;
59
60 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
61
62 segs = NULL;
63 goto out;
64 }
65
66 /* Fragment the skb. IP headers of the fragments are updated in
67 * inet_gso_segment()
68 */
69 if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
70 segs = skb_udp_tunnel_segment(skb, features);
71 else {
72 int offset;
73 __wsum csum;
74
75 /* Do software UFO. Complete and fill in the UDP checksum as
76 * HW cannot do checksum of UDP packets sent as multiple
77 * IP fragments.
78 */
79 offset = skb_checksum_start_offset(skb);
80 csum = skb_checksum(skb, offset, skb->len - offset, 0);
81 offset += skb->csum_offset;
82 *(__sum16 *)(skb->data + offset) = csum_fold(csum);
83 skb->ip_summed = CHECKSUM_NONE;
84
85 segs = skb_segment(skb, features);
86 }
87out:
88 return segs;
89}
90
91static const struct net_offload udpv4_offload = {
92 .callbacks = {
93 .gso_send_check = udp4_ufo_send_check,
94 .gso_segment = udp4_ufo_fragment,
95 },
96};
97
98int __init udpv4_offload_init(void)
99{
100 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
101}