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 <net/protocol.h>
16 #include "ip6_offload.h"
18 static int udp6_ufo_send_check(struct sk_buff
*skb
)
20 const struct ipv6hdr
*ipv6h
;
23 if (!pskb_may_pull(skb
, sizeof(*uh
)))
26 ipv6h
= ipv6_hdr(skb
);
29 uh
->check
= ~csum_ipv6_magic(&ipv6h
->saddr
, &ipv6h
->daddr
, skb
->len
,
31 skb
->csum_start
= skb_transport_header(skb
) - skb
->head
;
32 skb
->csum_offset
= offsetof(struct udphdr
, check
);
33 skb
->ip_summed
= CHECKSUM_PARTIAL
;
37 static struct sk_buff
*udp6_ufo_fragment(struct sk_buff
*skb
,
38 netdev_features_t features
)
40 struct sk_buff
*segs
= ERR_PTR(-EINVAL
);
42 unsigned int unfrag_ip6hlen
, unfrag_len
;
43 struct frag_hdr
*fptr
;
44 u8
*mac_start
, *prevhdr
;
46 u8 frag_hdr_sz
= sizeof(struct frag_hdr
);
50 mss
= skb_shinfo(skb
)->gso_size
;
51 if (unlikely(skb
->len
<= mss
))
54 if (skb_gso_ok(skb
, features
| NETIF_F_GSO_ROBUST
)) {
55 /* Packet is from an untrusted source, reset gso_segs. */
56 int type
= skb_shinfo(skb
)->gso_type
;
58 if (unlikely(type
& ~(SKB_GSO_UDP
| SKB_GSO_DODGY
) ||
59 !(type
& (SKB_GSO_UDP
))))
62 skb_shinfo(skb
)->gso_segs
= DIV_ROUND_UP(skb
->len
, mss
);
68 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
69 * do checksum of UDP packets sent as multiple IP fragments.
71 offset
= skb_checksum_start_offset(skb
);
72 csum
= skb_checksum(skb
, offset
, skb
->len
- offset
, 0);
73 offset
+= skb
->csum_offset
;
74 *(__sum16
*)(skb
->data
+ offset
) = csum_fold(csum
);
75 skb
->ip_summed
= CHECKSUM_NONE
;
77 /* Check if there is enough headroom to insert fragment header. */
78 if ((skb_mac_header(skb
) < skb
->head
+ frag_hdr_sz
) &&
79 pskb_expand_head(skb
, frag_hdr_sz
, 0, GFP_ATOMIC
))
82 /* Find the unfragmentable header and shift it left by frag_hdr_sz
83 * bytes to insert fragment header.
85 unfrag_ip6hlen
= ip6_find_1stfragopt(skb
, &prevhdr
);
87 *prevhdr
= NEXTHDR_FRAGMENT
;
88 unfrag_len
= skb_network_header(skb
) - skb_mac_header(skb
) +
90 mac_start
= skb_mac_header(skb
);
91 memmove(mac_start
-frag_hdr_sz
, mac_start
, unfrag_len
);
93 skb
->mac_header
-= frag_hdr_sz
;
94 skb
->network_header
-= frag_hdr_sz
;
96 fptr
= (struct frag_hdr
*)(skb_network_header(skb
) + unfrag_ip6hlen
);
97 fptr
->nexthdr
= nexthdr
;
99 ipv6_select_ident(fptr
, (struct rt6_info
*)skb_dst(skb
));
101 /* Fragment the skb. ipv6 header and the remaining fields of the
102 * fragment header are updated in ipv6_gso_segment()
104 segs
= skb_segment(skb
, features
);
109 static const struct net_offload udpv6_offload
= {
110 .gso_send_check
= udp6_ufo_send_check
,
111 .gso_segment
= udp6_ufo_fragment
,
114 int __init
udp_offload_init(void)
116 return inet6_add_offload(&udpv6_offload
, IPPROTO_UDP
);