Commit | Line | Data |
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da5bab07 DB |
1 | /* |
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 | ||
17 | static 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 | ||
39 | static 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 | | |
cb32f511 | 55 | SKB_GSO_IPIP | |
da5bab07 DB |
56 | 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 | } | |
87 | out: | |
88 | return segs; | |
89 | } | |
90 | ||
91 | static 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 | ||
98 | int __init udpv4_offload_init(void) | |
99 | { | |
100 | return inet_add_offload(&udpv4_offload, IPPROTO_UDP); | |
101 | } |