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         u16 mac_offset = skb->mac_header;
  27         netdev_features_t mpls_features;
  28         u16 mac_len = skb->mac_len;
  29         __be16 mpls_protocol;
  30         unsigned int mpls_hlen;
  31
  32         skb_reset_network_header(skb);
  33         mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
  34         if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
  35                 goto out;
  36
  37         /* Setup inner SKB. */
  38         mpls_protocol = skb->protocol;
  39         skb->protocol = skb->inner_protocol;
  40
  41         __skb_pull(skb, mpls_hlen);
  42
  43         skb->mac_len = 0;
  44         skb_reset_mac_header(skb);
  45
  46         /* Segment inner packet. */
  47         mpls_features = skb->dev->mpls_features & features;
  48         segs = skb_mac_gso_segment(skb, mpls_features);
  49         if (IS_ERR_OR_NULL(segs)) {
  50                 skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,
  51                                      mac_len);
  52                 goto out;
  53         }
  54         skb = segs;
  55
  56         mpls_hlen += mac_len;
  57         do {
  58                 skb->mac_len = mac_len;
  59                 skb->protocol = mpls_protocol;
  60
  61                 skb_reset_inner_network_header(skb);
  62
  63                 __skb_push(skb, mpls_hlen);
  64
  65                 skb_reset_mac_header(skb);
  66                 skb_set_network_header(skb, mac_len);
  67         } while ((skb = skb->next));
  68
  69 out:
  70         return segs;
  71 }
  72
  73 static struct packet_offload mpls_mc_offload __read_mostly = {
  74         .type = cpu_to_be16(ETH_P_MPLS_MC),
  75         .priority = 15,
  76         .callbacks = {
  77                 .gso_segment    =       mpls_gso_segment,
  78         },
  79 };
  80
  81 static struct packet_offload mpls_uc_offload __read_mostly = {
  82         .type = cpu_to_be16(ETH_P_MPLS_UC),
  83         .priority = 15,
  84         .callbacks = {
  85                 .gso_segment    =       mpls_gso_segment,
  86         },
  87 };
  88
  89 static int __init mpls_gso_init(void)
  90 {
  91         pr_info("MPLS GSO support\n");
  92
  93         dev_add_offload(&mpls_uc_offload);
  94         dev_add_offload(&mpls_mc_offload);
  95
  96         return 0;
  97 }
  98
  99 static void __exit mpls_gso_exit(void)
 100 {
 101         dev_remove_offload(&mpls_uc_offload);
 102         dev_remove_offload(&mpls_mc_offload);
 103 }
 104
 105 module_init(mpls_gso_init);
 106 module_exit(mpls_gso_exit);
 107
 108 MODULE_DESCRIPTION("MPLS GSO support");
 109 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
 110 MODULE_LICENSE("GPL");