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 SKB_GSO_GRE | 36 SKB_GSO_GRE_CSUM | 37 SKB_GSO_IPIP | 38 SKB_GSO_MPLS))) 39 goto out; 40 41 /* Setup inner SKB. */ 42 mpls_protocol = skb->protocol; 43 skb->protocol = skb->inner_protocol; 44 45 /* Push back the mac header that skb_mac_gso_segment() has pulled. 46 * It will be re-pulled by the call to skb_mac_gso_segment() below 47 */ 48 __skb_push(skb, skb->mac_len); 49 50 /* Segment inner packet. */ 51 mpls_features = skb->dev->mpls_features & netif_skb_features(skb); 52 segs = skb_mac_gso_segment(skb, mpls_features); 53 54 55 /* Restore outer protocol. */ 56 skb->protocol = mpls_protocol; 57 58 /* Re-pull the mac header that the call to skb_mac_gso_segment() 59 * above pulled. It will be re-pushed after returning 60 * skb_mac_gso_segment(), an indirect caller of this function. 61 */ 62 __skb_push(skb, skb->data - skb_mac_header(skb)); 63 64 out: 65 return segs; 66 } 67 68 static int mpls_gso_send_check(struct sk_buff *skb) 69 { 70 return 0; 71 } 72 73 static struct packet_offload mpls_mc_offload = { 74 .type = cpu_to_be16(ETH_P_MPLS_MC), 75 .callbacks = { 76 .gso_send_check = mpls_gso_send_check, 77 .gso_segment = mpls_gso_segment, 78 }, 79 }; 80 81 static struct packet_offload mpls_uc_offload = { 82 .type = cpu_to_be16(ETH_P_MPLS_UC), 83 .callbacks = { 84 .gso_send_check = mpls_gso_send_check, 85 .gso_segment = mpls_gso_segment, 86 }, 87 }; 88 89 static 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 99 static void __exit mpls_gso_exit(void) 100 { 101 dev_remove_offload(&mpls_uc_offload); 102 dev_remove_offload(&mpls_mc_offload); 103 } 104 105 module_init(mpls_gso_init); 106 module_exit(mpls_gso_exit); 107 108 MODULE_DESCRIPTION("MPLS GSO support"); 109 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)"); 110 MODULE_LICENSE("GPL"); 111