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1 | /* |
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> |
16 | #include <net/ip6_checksum.h> |
17 | #include "ip6_offload.h" |
18 | |
19 | static 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 | |
27 | if (likely(!skb->encapsulation)) { |
28 | ipv6h = ipv6_hdr(skb); |
29 | uh = udp_hdr(skb); |
30 | |
31 | 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 | |
38 | return 0; |
39 | } |
40 | |
41 | static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, |
42 | netdev_features_t features) |
43 | { |
44 | struct sk_buff *segs = ERR_PTR(-EINVAL); |
45 | unsigned int mss; |
46 | unsigned int unfrag_ip6hlen, unfrag_len; |
47 | struct frag_hdr *fptr; |
48 | u8 *packet_start, *prevhdr; |
49 | u8 nexthdr; |
50 | u8 frag_hdr_sz = sizeof(struct frag_hdr); |
51 | int offset; |
52 | __wsum csum; |
53 | int tnl_hlen; |
54 | |
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 | |
63 | if (unlikely(type & ~(SKB_GSO_UDP | |
64 | SKB_GSO_DODGY | |
65 | SKB_GSO_UDP_TUNNEL | |
66 | SKB_GSO_GRE | |
67 | SKB_GSO_IPIP | |
68 | SKB_GSO_SIT | |
69 | SKB_GSO_MPLS) || |
70 | !(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 | |
79 | if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) |
80 | segs = skb_udp_tunnel_segment(skb, features); |
81 | 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; |
90 | |
91 | /* Check if there is enough headroom to insert fragment header. */ |
92 | tnl_hlen = skb_tnl_header_len(skb); |
93 | if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) { |
94 | 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; |
116 | ipv6_select_ident(fptr, (struct rt6_info *)skb_dst(skb)); |
117 | |
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); |
122 | } |
123 | |
124 | out: |
125 | return segs; |
126 | } |
127 | static const struct net_offload udpv6_offload = { |
128 | .callbacks = { |
129 | .gso_send_check = udp6_ufo_send_check, |
130 | .gso_segment = udp6_ufo_fragment, |
131 | }, |
132 | }; |
133 | |
134 | int __init udp_offload_init(void) |
135 | { |
136 | return inet6_add_offload(&udpv6_offload, IPPROTO_UDP); |
137 | } |
138 |
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Tags:
od-2011-09-04
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v2.6.34-rc5
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