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 if (unlikely(skb_shinfo(skb)->gso_type & 30 ~(SKB_GSO_TCPV4 | 31 SKB_GSO_TCPV6 | 32 SKB_GSO_UDP | 33 SKB_GSO_DODGY | 34 SKB_GSO_TCP_ECN))) 35 goto out; 36 37 /* Setup inner SKB. */ 38 mpls_protocol = skb->protocol; 39 skb->protocol = skb->inner_protocol; 40 41 /* Push back the mac header that skb_mac_gso_segment() has pulled. 42 * It will be re-pulled by the call to skb_mac_gso_segment() below 43 */ 44 __skb_push(skb, skb->mac_len); 45 46 /* Segment inner packet. */ 47 mpls_features = skb->dev->mpls_features & features; 48 segs = skb_mac_gso_segment(skb, mpls_features); 49 50 51 /* Restore outer protocol. */ 52 skb->protocol = mpls_protocol; 53 54 /* Re-pull the mac header that the call to skb_mac_gso_segment() 55 * above pulled. It will be re-pushed after returning 56 * skb_mac_gso_segment(), an indirect caller of this function. 57 */ 58 __skb_pull(skb, skb->data - skb_mac_header(skb)); 59 out: 60 return segs; 61 } 62 63 static struct packet_offload mpls_mc_offload __read_mostly = { 64 .type = cpu_to_be16(ETH_P_MPLS_MC), 65 .callbacks = { 66 .gso_segment = mpls_gso_segment, 67 }, 68 }; 69 70 static struct packet_offload mpls_uc_offload __read_mostly = { 71 .type = cpu_to_be16(ETH_P_MPLS_UC), 72 .callbacks = { 73 .gso_segment = mpls_gso_segment, 74 }, 75 }; 76 77 static int __init mpls_gso_init(void) 78 { 79 pr_info("MPLS GSO support\n"); 80 81 dev_add_offload(&mpls_uc_offload); 82 dev_add_offload(&mpls_mc_offload); 83 84 return 0; 85 } 86 87 static void __exit mpls_gso_exit(void) 88 { 89 dev_remove_offload(&mpls_uc_offload); 90 dev_remove_offload(&mpls_mc_offload); 91 } 92 93 module_init(mpls_gso_init); 94 module_exit(mpls_gso_exit); 95 96 MODULE_DESCRIPTION("MPLS GSO support"); 97 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)"); 98 MODULE_LICENSE("GPL"); 99