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 18 static 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 65 out: 66 return segs; 67 } 68 69 static 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 77 static 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 85 static 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 95 static void __exit mpls_gso_exit(void) 96 { 97 dev_remove_offload(&mpls_uc_offload); 98 dev_remove_offload(&mpls_mc_offload); 99 } 100 101 module_init(mpls_gso_init); 102 module_exit(mpls_gso_exit); 103 104 MODULE_DESCRIPTION("MPLS GSO support"); 105 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)"); 106 MODULE_LICENSE("GPL"); 107