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 if (!skb_inner_network_header_was_set(skb)) 31 goto out; 32 33 skb_reset_network_header(skb); 34 mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb); 35 if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN)) 36 goto out; 37 if (unlikely(!pskb_may_pull(skb, mpls_hlen))) 38 goto out; 39 40 /* Setup inner SKB. */ 41 mpls_protocol = skb->protocol; 42 skb->protocol = skb->inner_protocol; 43 44 __skb_pull(skb, mpls_hlen); 45 46 skb->mac_len = 0; 47 skb_reset_mac_header(skb); 48 49 /* Segment inner packet. */ 50 mpls_features = skb->dev->mpls_features & features; 51 segs = skb_mac_gso_segment(skb, mpls_features); 52 if (IS_ERR_OR_NULL(segs)) { 53 skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset, 54 mac_len); 55 goto out; 56 } 57 skb = segs; 58 59 mpls_hlen += mac_len; 60 do { 61 skb->mac_len = mac_len; 62 skb->protocol = mpls_protocol; 63 64 skb_reset_inner_network_header(skb); 65 66 __skb_push(skb, mpls_hlen); 67 68 skb_reset_mac_header(skb); 69 skb_set_network_header(skb, mac_len); 70 } while ((skb = skb->next)); 71 72 out: 73 return segs; 74 } 75 76 static struct packet_offload mpls_mc_offload __read_mostly = { 77 .type = cpu_to_be16(ETH_P_MPLS_MC), 78 .priority = 15, 79 .callbacks = { 80 .gso_segment = mpls_gso_segment, 81 }, 82 }; 83 84 static struct packet_offload mpls_uc_offload __read_mostly = { 85 .type = cpu_to_be16(ETH_P_MPLS_UC), 86 .priority = 15, 87 .callbacks = { 88 .gso_segment = mpls_gso_segment, 89 }, 90 }; 91 92 static int __init mpls_gso_init(void) 93 { 94 pr_info("MPLS GSO support\n"); 95 96 dev_add_offload(&mpls_uc_offload); 97 dev_add_offload(&mpls_mc_offload); 98 99 return 0; 100 } 101 102 static void __exit mpls_gso_exit(void) 103 { 104 dev_remove_offload(&mpls_uc_offload); 105 dev_remove_offload(&mpls_mc_offload); 106 } 107 108 module_init(mpls_gso_init); 109 module_exit(mpls_gso_exit); 110 111 MODULE_DESCRIPTION("MPLS GSO support"); 112 MODULE_AUTHOR("Simon Horman <horms@verge.net.au>"); 113 MODULE_LICENSE("GPL"); 114