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Diffstat (limited to 'kernel/net/ipv4/xfrm4_mode_transport.c')
-rw-r--r--kernel/net/ipv4/xfrm4_mode_transport.c80
1 files changed, 80 insertions, 0 deletions
diff --git a/kernel/net/ipv4/xfrm4_mode_transport.c b/kernel/net/ipv4/xfrm4_mode_transport.c
new file mode 100644
index 000000000..fd840c7d7
--- /dev/null
+++ b/kernel/net/ipv4/xfrm4_mode_transport.c
@@ -0,0 +1,80 @@
+/*
+ * xfrm4_mode_transport.c - Transport mode encapsulation for IPv4.
+ *
+ * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/stringify.h>
+#include <net/dst.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+
+/* Add encapsulation header.
+ *
+ * The IP header will be moved forward to make space for the encapsulation
+ * header.
+ */
+static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+ struct iphdr *iph = ip_hdr(skb);
+ int ihl = iph->ihl * 4;
+
+ skb_set_network_header(skb, -x->props.header_len);
+ skb->mac_header = skb->network_header +
+ offsetof(struct iphdr, protocol);
+ skb->transport_header = skb->network_header + ihl;
+ __skb_pull(skb, ihl);
+ memmove(skb_network_header(skb), iph, ihl);
+ return 0;
+}
+
+/* Remove encapsulation header.
+ *
+ * The IP header will be moved over the top of the encapsulation header.
+ *
+ * On entry, skb->h shall point to where the IP header should be and skb->nh
+ * shall be set to where the IP header currently is. skb->data shall point
+ * to the start of the payload.
+ */
+static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int ihl = skb->data - skb_transport_header(skb);
+
+ if (skb->transport_header != skb->network_header) {
+ memmove(skb_transport_header(skb),
+ skb_network_header(skb), ihl);
+ skb->network_header = skb->transport_header;
+ }
+ ip_hdr(skb)->tot_len = htons(skb->len + ihl);
+ skb_reset_transport_header(skb);
+ return 0;
+}
+
+static struct xfrm_mode xfrm4_transport_mode = {
+ .input = xfrm4_transport_input,
+ .output = xfrm4_transport_output,
+ .owner = THIS_MODULE,
+ .encap = XFRM_MODE_TRANSPORT,
+};
+
+static int __init xfrm4_transport_init(void)
+{
+ return xfrm_register_mode(&xfrm4_transport_mode, AF_INET);
+}
+
+static void __exit xfrm4_transport_exit(void)
+{
+ int err;
+
+ err = xfrm_unregister_mode(&xfrm4_transport_mode, AF_INET);
+ BUG_ON(err);
+}
+
+module_init(xfrm4_transport_init);
+module_exit(xfrm4_transport_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TRANSPORT);