mpls_gso.c 2.4 KB

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