net/mpls/mpls_gso.c

   1 /*
   2  *      MPLS GSO Support
   3  *
   4  *      Authors: Simon Horman (horms@verge.net.au)
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  *
  11  *      Based on: GSO portions of net/ipv4/gre.c
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/err.h>
  17 #include <linux/module.h>
  18 #include <linux/netdev_features.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/skbuff.h>
  21
  22 static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
  23                                        netdev_features_t features)
  24 {
  25         struct sk_buff *segs = ERR_PTR(-EINVAL);
  26         netdev_features_t mpls_features;
  27         __be16 mpls_protocol;
  28
  29         if (unlikely(skb_shinfo(skb)->gso_type &
  30                                 ~(SKB_GSO_TCPV4 |
  31                                   SKB_GSO_TCPV6 |
  32                                   SKB_GSO_UDP |
  33                                   SKB_GSO_DODGY |
  34                                   SKB_GSO_TCP_ECN |
  35                                   SKB_GSO_GRE |
  36                                   SKB_GSO_GRE_CSUM |
  37                                   SKB_GSO_IPIP)))
  38                 goto out;
  39
  40         /* Setup inner SKB. */
  41         mpls_protocol = skb->protocol;
  42         skb->protocol = skb->inner_protocol;
  43
  44         /* Push back the mac header that skb_mac_gso_segment() has pulled.
  45          * It will be re-pulled by the call to skb_mac_gso_segment() below
  46          */
  47         __skb_push(skb, skb->mac_len);
  48
  49         /* Segment inner packet. */
  50         mpls_features = skb->dev->mpls_features & features;
  51         segs = skb_mac_gso_segment(skb, mpls_features);
  52
  53
  54         /* Restore outer protocol. */
  55         skb->protocol = mpls_protocol;
  56
  57         /* Re-pull the mac header that the call to skb_mac_gso_segment()
  58          * above pulled.  It will be re-pushed after returning
  59          * skb_mac_gso_segment(), an indirect caller of this function.
  60          */
  61         __skb_pull(skb, skb->data - skb_mac_header(skb));
  62 out:
  63         return segs;
  64 }
  65
  66 static struct packet_offload mpls_mc_offload = {
  67         .type = cpu_to_be16(ETH_P_MPLS_MC),
  68         .callbacks = {
  69                 .gso_segment    =       mpls_gso_segment,
  70         },
  71 };
  72
  73 static struct packet_offload mpls_uc_offload = {
  74         .type = cpu_to_be16(ETH_P_MPLS_UC),
  75         .callbacks = {
  76                 .gso_segment    =       mpls_gso_segment,
  77         },
  78 };
  79
  80 static int __init mpls_gso_init(void)
  81 {
  82         pr_info("MPLS GSO support\n");
  83
  84         dev_add_offload(&mpls_uc_offload);
  85         dev_add_offload(&mpls_mc_offload);
  86
  87         return 0;
  88 }
  89
  90 static void __exit mpls_gso_exit(void)
  91 {
  92         dev_remove_offload(&mpls_uc_offload);
  93         dev_remove_offload(&mpls_mc_offload);
  94 }
  95
  96 module_init(mpls_gso_init);
  97 module_exit(mpls_gso_exit);
  98
  99 MODULE_DESCRIPTION("MPLS GSO support");
 100 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
 101 MODULE_LICENSE("GPL");