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Vlad Yasevich5edbb072012-11-15 08:49:18 +00001/*
2 * IPV6 GSO/GRO offload support
3 * Linux INET6 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 * UDPv6 GSO support
11 */
12#include <linux/skbuff.h>
13#include <net/protocol.h>
14#include <net/ipv6.h>
15#include <net/udp.h>
Vlad Yasevichd4d0d352012-11-15 16:35:37 +000016#include <net/ip6_checksum.h>
Vlad Yasevich5edbb072012-11-15 08:49:18 +000017#include "ip6_offload.h"
18
19static int udp6_ufo_send_check(struct sk_buff *skb)
20{
21 const struct ipv6hdr *ipv6h;
22 struct udphdr *uh;
23
24 if (!pskb_may_pull(skb, sizeof(*uh)))
25 return -EINVAL;
26
Cong Wangd949d822013-08-31 13:44:37 +080027 if (likely(!skb->encapsulation)) {
28 ipv6h = ipv6_hdr(skb);
29 uh = udp_hdr(skb);
Vlad Yasevich5edbb072012-11-15 08:49:18 +000030
Cong Wangd949d822013-08-31 13:44:37 +080031 uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
32 IPPROTO_UDP, 0);
33 skb->csum_start = skb_transport_header(skb) - skb->head;
34 skb->csum_offset = offsetof(struct udphdr, check);
35 skb->ip_summed = CHECKSUM_PARTIAL;
36 }
37
Vlad Yasevich5edbb072012-11-15 08:49:18 +000038 return 0;
39}
40
41static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
Cong Wangd949d822013-08-31 13:44:37 +080042 netdev_features_t features)
Vlad Yasevich5edbb072012-11-15 08:49:18 +000043{
44 struct sk_buff *segs = ERR_PTR(-EINVAL);
45 unsigned int mss;
46 unsigned int unfrag_ip6hlen, unfrag_len;
47 struct frag_hdr *fptr;
Pravin B Shelar1e2bd512013-05-30 06:45:27 +000048 u8 *packet_start, *prevhdr;
Vlad Yasevich5edbb072012-11-15 08:49:18 +000049 u8 nexthdr;
50 u8 frag_hdr_sz = sizeof(struct frag_hdr);
51 int offset;
52 __wsum csum;
Pravin B Shelar1e2bd512013-05-30 06:45:27 +000053 int tnl_hlen;
Vlad Yasevich5edbb072012-11-15 08:49:18 +000054
55 mss = skb_shinfo(skb)->gso_size;
56 if (unlikely(skb->len <= mss))
57 goto out;
58
59 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
60 /* Packet is from an untrusted source, reset gso_segs. */
61 int type = skb_shinfo(skb)->gso_type;
62
Pravin B Shelar73136262013-03-07 13:21:51 +000063 if (unlikely(type & ~(SKB_GSO_UDP |
64 SKB_GSO_DODGY |
65 SKB_GSO_UDP_TUNNEL |
Simon Horman0d89d202013-05-23 21:02:52 +000066 SKB_GSO_GRE |
Eric Dumazetcb32f512013-10-19 11:42:57 -070067 SKB_GSO_IPIP |
Eric Dumazet61c1db72013-10-20 20:47:30 -070068 SKB_GSO_SIT |
Simon Horman0d89d202013-05-23 21:02:52 +000069 SKB_GSO_MPLS) ||
Vlad Yasevich5edbb072012-11-15 08:49:18 +000070 !(type & (SKB_GSO_UDP))))
71 goto out;
72
73 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
74
75 segs = NULL;
76 goto out;
77 }
78
Cong Wangd949d822013-08-31 13:44:37 +080079 if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
Cong Wangeb3c0d82013-08-31 13:44:38 +080080 segs = skb_udp_tunnel_segment(skb, features);
Cong Wangd949d822013-08-31 13:44:37 +080081 else {
82 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
83 * do checksum of UDP packets sent as multiple IP fragments.
84 */
85 offset = skb_checksum_start_offset(skb);
86 csum = skb_checksum(skb, offset, skb->len - offset, 0);
87 offset += skb->csum_offset;
88 *(__sum16 *)(skb->data + offset) = csum_fold(csum);
89 skb->ip_summed = CHECKSUM_NONE;
Vlad Yasevich5edbb072012-11-15 08:49:18 +000090
Cong Wangd949d822013-08-31 13:44:37 +080091 /* Check if there is enough headroom to insert fragment header. */
92 tnl_hlen = skb_tnl_header_len(skb);
Hannes Frederic Sowa0e033e02013-11-05 02:41:27 +010093 if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
Cong Wangd949d822013-08-31 13:44:37 +080094 if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
95 goto out;
96 }
97
98 /* Find the unfragmentable header and shift it left by frag_hdr_sz
99 * bytes to insert fragment header.
100 */
101 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
102 nexthdr = *prevhdr;
103 *prevhdr = NEXTHDR_FRAGMENT;
104 unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
105 unfrag_ip6hlen + tnl_hlen;
106 packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
107 memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);
108
109 SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
110 skb->mac_header -= frag_hdr_sz;
111 skb->network_header -= frag_hdr_sz;
112
113 fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
114 fptr->nexthdr = nexthdr;
115 fptr->reserved = 0;
Hannes Frederic Sowa916e4cf2014-02-21 02:55:35 +0100116 fptr->identification = skb_shinfo(skb)->ip6_frag_id;
Cong Wangd949d822013-08-31 13:44:37 +0800117
118 /* Fragment the skb. ipv6 header and the remaining fields of the
119 * fragment header are updated in ipv6_gso_segment()
120 */
121 segs = skb_segment(skb, features);
Pravin B Shelar1e2bd512013-05-30 06:45:27 +0000122 }
Vlad Yasevich5edbb072012-11-15 08:49:18 +0000123
Vlad Yasevich5edbb072012-11-15 08:49:18 +0000124out:
125 return segs;
126}
127static const struct net_offload udpv6_offload = {
Vlad Yasevichf191a1d2012-11-15 08:49:23 +0000128 .callbacks = {
129 .gso_send_check = udp6_ufo_send_check,
130 .gso_segment = udp6_ufo_fragment,
131 },
Vlad Yasevich5edbb072012-11-15 08:49:18 +0000132};
133
134int __init udp_offload_init(void)
135{
136 return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
137}