LXR linux/net/mpls/mpls

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *      MPLS GSO Support
   4 *
   5 *      Authors: Simon Horman (horms@verge.net.au)
   6 *
   7 *      Based on: GSO portions of net/ipv4/gre.c
   8 */
   9
  10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12#include <linux/err.h>
  13#include <linux/module.h>
  14#include <linux/netdev_features.h>
  15#include <linux/netdevice.h>
  16#include <linux/skbuff.h>
  17
  18static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
  19                                       netdev_features_t features)
  20{
  21        struct sk_buff *segs = ERR_PTR(-EINVAL);
  22        u16 mac_offset = skb->mac_header;
  23        netdev_features_t mpls_features;
  24        u16 mac_len = skb->mac_len;
  25        __be16 mpls_protocol;
  26        unsigned int mpls_hlen;
  27
  28        skb_reset_network_header(skb);
  29        mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
  30        if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
  31                goto out;
  32
  33        /* Setup inner SKB. */
  34        mpls_protocol = skb->protocol;
  35        skb->protocol = skb->inner_protocol;
  36
  37        __skb_pull(skb, mpls_hlen);
  38
  39        skb->mac_len = 0;
  40        skb_reset_mac_header(skb);
  41
  42        /* Segment inner packet. */
  43        mpls_features = skb->dev->mpls_features & features;
  44        segs = skb_mac_gso_segment(skb, mpls_features);
  45        if (IS_ERR_OR_NULL(segs)) {
  46                skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,
  47                                     mac_len);
  48                goto out;
  49        }
  50        skb = segs;
  51
  52        mpls_hlen += mac_len;
  53        do {
  54                skb->mac_len = mac_len;
  55                skb->protocol = mpls_protocol;
  56
  57                skb_reset_inner_network_header(skb);
  58
  59                __skb_push(skb, mpls_hlen);
  60
  61                skb_reset_mac_header(skb);
  62                skb_set_network_header(skb, mac_len);
  63        } while ((skb = skb->next));
  64
  65out:
  66        return segs;
  67}
  68
  69static struct packet_offload mpls_mc_offload __read_mostly = {
  70        .type = cpu_to_be16(ETH_P_MPLS_MC),
  71        .priority = 15,
  72        .callbacks = {
  73                .gso_segment    =       mpls_gso_segment,
  74        },
  75};
  76
  77static struct packet_offload mpls_uc_offload __read_mostly = {
  78        .type = cpu_to_be16(ETH_P_MPLS_UC),
  79        .priority = 15,
  80        .callbacks = {
  81                .gso_segment    =       mpls_gso_segment,
  82        },
  83};
  84
  85static int __init mpls_gso_init(void)
  86{
  87        pr_info("MPLS GSO support\n");
  88
  89        dev_add_offload(&mpls_uc_offload);
  90        dev_add_offload(&mpls_mc_offload);
  91
  92        return 0;
  93}
  94
  95static void __exit mpls_gso_exit(void)
  96{
  97        dev_remove_offload(&mpls_uc_offload);
  98        dev_remove_offload(&mpls_mc_offload);
  99}
 100
 101module_init(mpls_gso_init);
 102module_exit(mpls_gso_exit);
 103
 104MODULE_DESCRIPTION("MPLS GSO support");
 105MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
 106MODULE_LICENSE("GPL");
 107