2 * IPV6 GSO/GRO offload support
3 * Linux INET6 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.
12 #include <linux/skbuff.h>
13 #include <linux/netdevice.h>
14 #include <net/protocol.h>
17 #include <net/ip6_checksum.h>
18 #include "ip6_offload.h"
20 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
21 netdev_features_t features)
23 struct sk_buff *segs = ERR_PTR(-EINVAL);
25 unsigned int unfrag_ip6hlen, unfrag_len;
26 struct frag_hdr *fptr;
27 u8 *packet_start, *prevhdr;
29 u8 frag_hdr_sz = sizeof(struct frag_hdr);
34 mss = skb_shinfo(skb)->gso_size;
35 if (unlikely(skb->len <= mss))
38 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
39 /* Packet is from an untrusted source, reset gso_segs. */
41 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
43 /* Set the IPv6 fragment id if not set yet */
44 if (!skb_shinfo(skb)->ip6_frag_id)
45 ipv6_proxy_select_ident(dev_net(skb->dev), skb);
51 if (skb->encapsulation && skb_shinfo(skb)->gso_type &
52 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
53 segs = skb_udp_tunnel_segment(skb, features, true);
55 const struct ipv6hdr *ipv6h;
58 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
61 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
64 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
65 * do checksum of UDP packets sent as multiple IP fragments.
69 ipv6h = ipv6_hdr(skb);
72 csum = skb_checksum(skb, 0, skb->len, 0);
73 uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
76 uh->check = CSUM_MANGLED_0;
78 skb->ip_summed = CHECKSUM_UNNECESSARY;
80 /* If there is no outer header we can fake a checksum offload
81 * due to the fact that we have already done the checksum in
82 * software prior to segmenting the frame.
84 if (!skb->encap_hdr_csum)
85 features |= NETIF_F_HW_CSUM;
87 /* Check if there is enough headroom to insert fragment header. */
88 tnl_hlen = skb_tnl_header_len(skb);
89 if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
90 if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
94 /* Find the unfragmentable header and shift it left by frag_hdr_sz
95 * bytes to insert fragment header.
97 err = ip6_find_1stfragopt(skb, &prevhdr);
100 unfrag_ip6hlen = err;
102 *prevhdr = NEXTHDR_FRAGMENT;
103 unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
104 unfrag_ip6hlen + tnl_hlen;
105 packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
106 memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);
108 SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
109 skb->mac_header -= frag_hdr_sz;
110 skb->network_header -= frag_hdr_sz;
112 fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
113 fptr->nexthdr = nexthdr;
115 if (!skb_shinfo(skb)->ip6_frag_id)
116 ipv6_proxy_select_ident(dev_net(skb->dev), skb);
117 fptr->identification = skb_shinfo(skb)->ip6_frag_id;
119 /* Fragment the skb. ipv6 header and the remaining fields of the
120 * fragment header are updated in ipv6_gso_segment()
122 segs = skb_segment(skb, features);
129 static struct sk_buff **udp6_gro_receive(struct sk_buff **head,
132 struct udphdr *uh = udp_gro_udphdr(skb);
137 /* Don't bother verifying checksum if we're going to flush anyway. */
138 if (NAPI_GRO_CB(skb)->flush)
141 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
142 ip6_gro_compute_pseudo))
145 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
146 ip6_gro_compute_pseudo);
149 NAPI_GRO_CB(skb)->is_ipv6 = 1;
150 return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb);
153 NAPI_GRO_CB(skb)->flush = 1;
157 static int udp6_gro_complete(struct sk_buff *skb, int nhoff)
159 const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
160 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
163 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
164 uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr,
167 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
170 return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb);
173 static const struct net_offload udpv6_offload = {
175 .gso_segment = udp6_ufo_fragment,
176 .gro_receive = udp6_gro_receive,
177 .gro_complete = udp6_gro_complete,
181 int udpv6_offload_init(void)
183 return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
186 int udpv6_offload_exit(void)
188 return inet6_del_offload(&udpv6_offload, IPPROTO_UDP);