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 #include <net/mpls.h> 18 19 static struct sk_buff *mpls_gso_segment(struct sk_buff *skb, 20 netdev_features_t features) 21 { 22 struct sk_buff *segs = ERR_PTR(-EINVAL); 23 u16 mac_offset = skb->mac_header; 24 netdev_features_t mpls_features; 25 u16 mac_len = skb->mac_len; 26 __be16 mpls_protocol; 27 unsigned int mpls_hlen; 28 29 skb_reset_network_header(skb); 30 mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb); 31 if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN)) 32 goto out; 33 if (unlikely(!pskb_may_pull(skb, mpls_hlen))) 34 goto out; 35 36 /* Setup inner SKB. */ 37 mpls_protocol = skb->protocol; 38 skb->protocol = skb->inner_protocol; 39 40 __skb_pull(skb, mpls_hlen); 41 42 skb->mac_len = 0; 43 skb_reset_mac_header(skb); 44 45 /* Segment inner packet. */ 46 mpls_features = skb->dev->mpls_features & features; 47 segs = skb_mac_gso_segment(skb, mpls_features); 48 if (IS_ERR_OR_NULL(segs)) { 49 skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset, 50 mac_len); 51 goto out; 52 } 53 skb = segs; 54 55 mpls_hlen += mac_len; 56 do { 57 skb->mac_len = mac_len; 58 skb->protocol = mpls_protocol; 59 60 skb_reset_inner_network_header(skb); 61 62 __skb_push(skb, mpls_hlen); 63 64 skb_reset_mac_header(skb); 65 skb_set_network_header(skb, mac_len); 66 } while ((skb = skb->next)); 67 68 out: 69 return segs; 70 } 71 72 static struct packet_offload mpls_mc_offload __read_mostly = { 73 .type = cpu_to_be16(ETH_P_MPLS_MC), 74 .priority = 15, 75 .callbacks = { 76 .gso_segment = mpls_gso_segment, 77 }, 78 }; 79 80 static struct packet_offload mpls_uc_offload __read_mostly = { 81 .type = cpu_to_be16(ETH_P_MPLS_UC), 82 .priority = 15, 83 .callbacks = { 84 .gso_segment = mpls_gso_segment, 85 }, 86 }; 87 88 static int __init mpls_gso_init(void) 89 { 90 pr_info("MPLS GSO support\n"); 91 92 dev_add_offload(&mpls_uc_offload); 93 dev_add_offload(&mpls_mc_offload); 94 95 return 0; 96 } 97 98 static void __exit mpls_gso_exit(void) 99 { 100 dev_remove_offload(&mpls_uc_offload); 101 dev_remove_offload(&mpls_mc_offload); 102 } 103 104 module_init(mpls_gso_init); 105 module_exit(mpls_gso_exit); 106 107 MODULE_DESCRIPTION("MPLS GSO support"); 108 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)"); 109 MODULE_LICENSE("GPL"); 110