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 /* Setup inner SKB. */ 30 mpls_protocol = skb->protocol; 31 skb->protocol = skb->inner_protocol; 32 33 /* Push back the mac header that skb_mac_gso_segment() has pulled. 34 * It will be re-pulled by the call to skb_mac_gso_segment() below 35 */ 36 __skb_push(skb, skb->mac_len); 37 38 /* Segment inner packet. */ 39 mpls_features = skb->dev->mpls_features & features; 40 segs = skb_mac_gso_segment(skb, mpls_features); 41 42 43 /* Restore outer protocol. */ 44 skb->protocol = mpls_protocol; 45 46 /* Re-pull the mac header that the call to skb_mac_gso_segment() 47 * above pulled. It will be re-pushed after returning 48 * skb_mac_gso_segment(), an indirect caller of this function. 49 */ 50 __skb_pull(skb, skb->data - skb_mac_header(skb)); 51 52 return segs; 53 } 54 55 static struct packet_offload mpls_mc_offload __read_mostly = { 56 .type = cpu_to_be16(ETH_P_MPLS_MC), 57 .priority = 15, 58 .callbacks = { 59 .gso_segment = mpls_gso_segment, 60 }, 61 }; 62 63 static struct packet_offload mpls_uc_offload __read_mostly = { 64 .type = cpu_to_be16(ETH_P_MPLS_UC), 65 .priority = 15, 66 .callbacks = { 67 .gso_segment = mpls_gso_segment, 68 }, 69 }; 70 71 static int __init mpls_gso_init(void) 72 { 73 pr_info("MPLS GSO support\n"); 74 75 dev_add_offload(&mpls_uc_offload); 76 dev_add_offload(&mpls_mc_offload); 77 78 return 0; 79 } 80 81 static void __exit mpls_gso_exit(void) 82 { 83 dev_remove_offload(&mpls_uc_offload); 84 dev_remove_offload(&mpls_mc_offload); 85 } 86 87 module_init(mpls_gso_init); 88 module_exit(mpls_gso_exit); 89 90 MODULE_DESCRIPTION("MPLS GSO support"); 91 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)"); 92 MODULE_LICENSE("GPL"); 93