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/gso.h> 18 #include <net/mpls.h> 19 20 static struct sk_buff *mpls_gso_segment(struct sk_buff *skb, 21 netdev_features_t features) 22 { 23 struct sk_buff *segs = ERR_PTR(-EINVAL); 24 u16 mac_offset = skb->mac_header; 25 netdev_features_t mpls_features; 26 u16 mac_len = skb->mac_len; 27 __be16 mpls_protocol; 28 unsigned int mpls_hlen; 29 30 skb_reset_network_header(skb); 31 mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb); 32 if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN)) 33 goto out; 34 if (unlikely(!pskb_may_pull(skb, mpls_hlen))) 35 goto out; 36 37 /* Setup inner SKB. */ 38 mpls_protocol = skb->protocol; 39 skb->protocol = skb->inner_protocol; 40 41 __skb_pull(skb, mpls_hlen); 42 43 skb->mac_len = 0; 44 skb_reset_mac_header(skb); 45 46 /* Segment inner packet. */ 47 mpls_features = skb->dev->mpls_features & features; 48 segs = skb_mac_gso_segment(skb, mpls_features); 49 if (IS_ERR_OR_NULL(segs)) { 50 skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset, 51 mac_len); 52 goto out; 53 } 54 skb = segs; 55 56 mpls_hlen += mac_len; 57 do { 58 skb->mac_len = mac_len; 59 skb->protocol = mpls_protocol; 60 61 skb_reset_inner_network_header(skb); 62 63 __skb_push(skb, mpls_hlen); 64 65 skb_reset_mac_header(skb); 66 skb_set_network_header(skb, mac_len); 67 } while ((skb = skb->next)); 68 69 out: 70 return segs; 71 } 72 73 static struct packet_offload mpls_mc_offload __read_mostly = { 74 .type = cpu_to_be16(ETH_P_MPLS_MC), 75 .priority = 15, 76 .callbacks = { 77 .gso_segment = mpls_gso_segment, 78 }, 79 }; 80 81 static struct packet_offload mpls_uc_offload __read_mostly = { 82 .type = cpu_to_be16(ETH_P_MPLS_UC), 83 .priority = 15, 84 .callbacks = { 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