1 files changed, 92 insertions, 0 deletions
diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
new file mode 100644
index 0000000..8c3180a
--- /dev/null
+++ b/net/ipv4/xfrm4_output.c
@@ -0,0 +1,92 @@
+/*
+ * xfrm4_output.c - Common IPsec encapsulation code for IPv4.
+ * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/if_ether.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter_ipv4.h>
+#include <net/dst.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+#include <net/icmp.h>
+
+static int xfrm4_tunnel_check_size(struct sk_buff *skb)
+{
+	int mtu, ret = 0;
+	struct dst_entry *dst;
+
+	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
+		goto out;
+
+	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->local_df)
+		goto out;
+
+	dst = skb->dst;
+	mtu = dst_mtu(dst);
+	if (skb->len > mtu) {
+		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
+		ret = -EMSGSIZE;
+	}
+out:
+	return ret;
+}
+
+int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	int err;
+
+	err = xfrm4_tunnel_check_size(skb);
+	if (err)
+		return err;
+
+	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
+
+	return xfrm4_extract_header(skb);
+}
+
+int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	int err;
+
+	err = xfrm_inner_extract_output(x, skb);
+	if (err)
+		return err;
+
+	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED;
+
+	skb->protocol = htons(ETH_P_IP);
+
+	return x->outer_mode->output2(x, skb);
+}
+EXPORT_SYMBOL(xfrm4_prepare_output);
+
+static int xfrm4_output_finish(struct sk_buff *skb)
+{
+#ifdef CONFIG_NETFILTER
+	if (!skb->dst->xfrm) {
+		IPCB(skb)->flags |= IPSKB_REROUTED;
+		return dst_output(skb);
+	}
+
+	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
+#endif
+
+	skb->protocol = htons(ETH_P_IP);
+	return xfrm_output(skb);
+}
+
+int xfrm4_output(struct sk_buff *skb)
+{
+	return NF_HOOK_COND(PF_INET, NF_INET_POST_ROUTING, skb,
+			    NULL, skb->dst->dev, xfrm4_output_finish,
+			    !(IPCB(skb)->flags & IPSKB_REROUTED));
+}