LXR linux/net/mpls/mpls

   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
  22static 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
  69out:
  70        return segs;
  71}
  72
  73static 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
  81static 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
  89static 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
  99static void __exit mpls_gso_exit(void)
 100{
 101        dev_remove_offload(&mpls_uc_offload);
 102        dev_remove_offload(&mpls_mc_offload);
 103}
 104
 105module_init(mpls_gso_init);
 106module_exit(mpls_gso_exit);
 107
 108MODULE_DESCRIPTION("MPLS GSO support");
 109MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
 110MODULE_LICENSE("GPL");
 111