| Daniel Borkmann | c50cd35 | 2013-07-01 19:24:00 +0200 | [diff] [blame^] | 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 | * GRE GSO support |
| 11 | */ |
| 12 | |
| 13 | #include <linux/skbuff.h> |
| 14 | #include <net/protocol.h> |
| 15 | #include <net/gre.h> |
| 16 | |
| 17 | static int gre_gso_send_check(struct sk_buff *skb) |
| 18 | { |
| 19 | if (!skb->encapsulation) |
| 20 | return -EINVAL; |
| 21 | return 0; |
| 22 | } |
| 23 | |
| 24 | static struct sk_buff *gre_gso_segment(struct sk_buff *skb, |
| 25 | netdev_features_t features) |
| 26 | { |
| 27 | struct sk_buff *segs = ERR_PTR(-EINVAL); |
| 28 | netdev_features_t enc_features; |
| 29 | int ghl = GRE_HEADER_SECTION; |
| 30 | struct gre_base_hdr *greh; |
| 31 | int mac_len = skb->mac_len; |
| 32 | __be16 protocol = skb->protocol; |
| 33 | int tnl_hlen; |
| 34 | bool csum; |
| 35 | |
| 36 | if (unlikely(skb_shinfo(skb)->gso_type & |
| 37 | ~(SKB_GSO_TCPV4 | |
| 38 | SKB_GSO_TCPV6 | |
| 39 | SKB_GSO_UDP | |
| 40 | SKB_GSO_DODGY | |
| 41 | SKB_GSO_TCP_ECN | |
| 42 | SKB_GSO_GRE))) |
| 43 | goto out; |
| 44 | |
| 45 | if (unlikely(!pskb_may_pull(skb, sizeof(*greh)))) |
| 46 | goto out; |
| 47 | |
| 48 | greh = (struct gre_base_hdr *)skb_transport_header(skb); |
| 49 | |
| 50 | if (greh->flags & GRE_KEY) |
| 51 | ghl += GRE_HEADER_SECTION; |
| 52 | if (greh->flags & GRE_SEQ) |
| 53 | ghl += GRE_HEADER_SECTION; |
| 54 | if (greh->flags & GRE_CSUM) { |
| 55 | ghl += GRE_HEADER_SECTION; |
| 56 | csum = true; |
| 57 | } else |
| 58 | csum = false; |
| 59 | |
| 60 | /* setup inner skb. */ |
| 61 | skb->protocol = greh->protocol; |
| 62 | skb->encapsulation = 0; |
| 63 | |
| 64 | if (unlikely(!pskb_may_pull(skb, ghl))) |
| 65 | goto out; |
| 66 | |
| 67 | __skb_pull(skb, ghl); |
| 68 | skb_reset_mac_header(skb); |
| 69 | skb_set_network_header(skb, skb_inner_network_offset(skb)); |
| 70 | skb->mac_len = skb_inner_network_offset(skb); |
| 71 | |
| 72 | /* segment inner packet. */ |
| 73 | enc_features = skb->dev->hw_enc_features & netif_skb_features(skb); |
| 74 | segs = skb_mac_gso_segment(skb, enc_features); |
| 75 | if (!segs || IS_ERR(segs)) |
| 76 | goto out; |
| 77 | |
| 78 | skb = segs; |
| 79 | tnl_hlen = skb_tnl_header_len(skb); |
| 80 | do { |
| 81 | __skb_push(skb, ghl); |
| 82 | if (csum) { |
| 83 | __be32 *pcsum; |
| 84 | |
| 85 | if (skb_has_shared_frag(skb)) { |
| 86 | int err; |
| 87 | |
| 88 | err = __skb_linearize(skb); |
| 89 | if (err) { |
| 90 | kfree_skb(segs); |
| 91 | segs = ERR_PTR(err); |
| 92 | goto out; |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | greh = (struct gre_base_hdr *)(skb->data); |
| 97 | pcsum = (__be32 *)(greh + 1); |
| 98 | *pcsum = 0; |
| 99 | *(__sum16 *)pcsum = csum_fold(skb_checksum(skb, 0, skb->len, 0)); |
| 100 | } |
| 101 | __skb_push(skb, tnl_hlen - ghl); |
| 102 | |
| 103 | skb_reset_mac_header(skb); |
| 104 | skb_set_network_header(skb, mac_len); |
| 105 | skb->mac_len = mac_len; |
| 106 | skb->protocol = protocol; |
| 107 | } while ((skb = skb->next)); |
| 108 | out: |
| 109 | return segs; |
| 110 | } |
| 111 | |
| 112 | static const struct net_offload gre_offload = { |
| 113 | .callbacks = { |
| 114 | .gso_send_check = gre_gso_send_check, |
| 115 | .gso_segment = gre_gso_segment, |
| 116 | }, |
| 117 | }; |
| 118 | |
| 119 | int __init gre_offload_init(void) |
| 120 | { |
| 121 | return inet_add_offload(&gre_offload, IPPROTO_GRE); |
| 122 | } |
| 123 | |
| 124 | void __exit gre_offload_exit(void) |
| 125 | { |
| 126 | inet_del_offload(&gre_offload, IPPROTO_GRE); |
| 127 | } |