1 /* 2 * xfrm6_mode_transport.c - Transport mode encapsulation for IPv6. 3 * 4 * Copyright (C) 2002 USAGI/WIDE Project 5 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au> 6 */ 7 8 #include <linux/init.h> 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/skbuff.h> 12 #include <linux/stringify.h> 13 #include <net/dst.h> 14 #include <net/ipv6.h> 15 #include <net/xfrm.h> 16 #include <net/protocol.h> 17 18 /* Add encapsulation header. 19 * 20 * The IP header and mutable extension headers will be moved forward to make 21 * space for the encapsulation header. 22 */ 23 static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb) 24 { 25 struct ipv6hdr *iph; 26 u8 *prevhdr; 27 int hdr_len; 28 29 iph = ipv6_hdr(skb); 30 skb_set_inner_transport_header(skb, skb_transport_offset(skb)); 31 32 hdr_len = x->type->hdr_offset(x, skb, &prevhdr); 33 if (hdr_len < 0) 34 return hdr_len; 35 skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data); 36 skb_set_network_header(skb, -x->props.header_len); 37 skb->transport_header = skb->network_header + hdr_len; 38 __skb_pull(skb, hdr_len); 39 memmove(ipv6_hdr(skb), iph, hdr_len); 40 return 0; 41 } 42 43 /* Remove encapsulation header. 44 * 45 * The IP header will be moved over the top of the encapsulation header. 46 * 47 * On entry, skb->h shall point to where the IP header should be and skb->nh 48 * shall be set to where the IP header currently is. skb->data shall point 49 * to the start of the payload. 50 */ 51 static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb) 52 { 53 int ihl = skb->data - skb_transport_header(skb); 54 55 if (skb->transport_header != skb->network_header) { 56 memmove(skb_transport_header(skb), 57 skb_network_header(skb), ihl); 58 skb->network_header = skb->transport_header; 59 } 60 ipv6_hdr(skb)->payload_len = htons(skb->len + ihl - 61 sizeof(struct ipv6hdr)); 62 skb_reset_transport_header(skb); 63 return 0; 64 } 65 66 static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x, 67 struct sk_buff *skb, 68 netdev_features_t features) 69 { 70 const struct net_offload *ops; 71 struct sk_buff *segs = ERR_PTR(-EINVAL); 72 struct xfrm_offload *xo = xfrm_offload(skb); 73 74 skb->transport_header += x->props.header_len; 75 ops = rcu_dereference(inet6_offloads[xo->proto]); 76 if (likely(ops && ops->callbacks.gso_segment)) 77 segs = ops->callbacks.gso_segment(skb, features); 78 79 return segs; 80 } 81 82 static void xfrm6_transport_xmit(struct xfrm_state *x, struct sk_buff *skb) 83 { 84 struct xfrm_offload *xo = xfrm_offload(skb); 85 86 skb_reset_mac_len(skb); 87 pskb_pull(skb, skb->mac_len + sizeof(struct ipv6hdr) + x->props.header_len); 88 89 if (xo->flags & XFRM_GSO_SEGMENT) { 90 skb_reset_transport_header(skb); 91 skb->transport_header -= x->props.header_len; 92 } 93 } 94 95 96 static struct xfrm_mode xfrm6_transport_mode = { 97 .input = xfrm6_transport_input, 98 .output = xfrm6_transport_output, 99 .gso_segment = xfrm4_transport_gso_segment, 100 .xmit = xfrm6_transport_xmit, 101 .owner = THIS_MODULE, 102 .encap = XFRM_MODE_TRANSPORT, 103 }; 104 105 static int __init xfrm6_transport_init(void) 106 { 107 return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6); 108 } 109 110 static void __exit xfrm6_transport_exit(void) 111 { 112 int err; 113 114 err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6); 115 BUG_ON(err); 116 } 117 118 module_init(xfrm6_transport_init); 119 module_exit(xfrm6_transport_exit); 120 MODULE_LICENSE("GPL"); 121 MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT); 122
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