1 /* 2 * Network Service Header 3 * 4 * Copyright (c) 2017 Red Hat, Inc. -- Jiri Benc <jbenc@redhat.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11 #include <linux/module.h> 12 #include <linux/netdevice.h> 13 #include <linux/skbuff.h> 14 #include <net/nsh.h> 15 #include <net/tun_proto.h> 16 17 static struct sk_buff *nsh_gso_segment(struct sk_buff *skb, 18 netdev_features_t features) 19 { 20 struct sk_buff *segs = ERR_PTR(-EINVAL); 21 unsigned int nsh_len, mac_len; 22 __be16 proto; 23 int nhoff; 24 25 skb_reset_network_header(skb); 26 27 nhoff = skb->network_header - skb->mac_header; 28 mac_len = skb->mac_len; 29 30 if (unlikely(!pskb_may_pull(skb, NSH_BASE_HDR_LEN))) 31 goto out; 32 nsh_len = nsh_hdr_len(nsh_hdr(skb)); 33 if (unlikely(!pskb_may_pull(skb, nsh_len))) 34 goto out; 35 36 proto = tun_p_to_eth_p(nsh_hdr(skb)->np); 37 if (!proto) 38 goto out; 39 40 __skb_pull(skb, nsh_len); 41 42 skb_reset_mac_header(skb); 43 skb_reset_mac_len(skb); 44 skb->protocol = proto; 45 46 features &= NETIF_F_SG; 47 segs = skb_mac_gso_segment(skb, features); 48 if (IS_ERR_OR_NULL(segs)) { 49 skb_gso_error_unwind(skb, htons(ETH_P_NSH), nsh_len, 50 skb->network_header - nhoff, 51 mac_len); 52 goto out; 53 } 54 55 for (skb = segs; skb; skb = skb->next) { 56 skb->protocol = htons(ETH_P_NSH); 57 __skb_push(skb, nsh_len); 58 skb_set_mac_header(skb, -nhoff); 59 skb->network_header = skb->mac_header + mac_len; 60 skb->mac_len = mac_len; 61 } 62 63 out: 64 return segs; 65 } 66 67 static struct packet_offload nsh_packet_offload __read_mostly = { 68 .type = htons(ETH_P_NSH), 69 .priority = 15, 70 .callbacks = { 71 .gso_segment = nsh_gso_segment, 72 }, 73 }; 74 75 static int __init nsh_init_module(void) 76 { 77 dev_add_offload(&nsh_packet_offload); 78 return 0; 79 } 80 81 static void __exit nsh_cleanup_module(void) 82 { 83 dev_remove_offload(&nsh_packet_offload); 84 } 85 86 module_init(nsh_init_module); 87 module_exit(nsh_cleanup_module); 88 89 MODULE_AUTHOR("Jiri Benc <jbenc@redhat.com>"); 90 MODULE_DESCRIPTION("NSH protocol"); 91 MODULE_LICENSE("GPL v2"); 92