[IPSEC]: Move common output code to xfrm_output

Most of the code in xfrm4_output_one and xfrm6_output_one are identical so
this patch moves them into a common xfrm_output function which will live
in net/xfrm.

In fact this would seem to fix a bug as on IPv4 we never reset the network
header after a transform which may upset netfilter later on.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 73 insertions, 0 deletions

diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
new file mode 100644
index 0000000..75f289b
--- /dev/null
+++ b/net/xfrm/xfrm_output.c
@@ -0,0 +1,73 @@
+/*
+ * xfrm_output.c - Common IPsec encapsulation code.
+ *
+ * Copyright (c) 2007 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/errno.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/time.h>
+#include <net/dst.h>
+#include <net/xfrm.h>
+
+int xfrm_output(struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb->dst;
+	struct xfrm_state *x = dst->xfrm;
+	int err;
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		err = skb_checksum_help(skb);
+		if (err)
+			goto error_nolock;
+	}
+
+	do {
+		spin_lock_bh(&x->lock);
+		err = xfrm_state_check(x, skb);
+		if (err)
+			goto error;
+
+		err = x->mode->output(x, skb);
+		if (err)
+			goto error;
+
+		err = x->type->output(x, skb);
+		if (err)
+			goto error;
+
+		x->curlft.bytes += skb->len;
+		x->curlft.packets++;
+
+		if (x->props.mode == XFRM_MODE_ROUTEOPTIMIZATION)
+			x->lastused = get_seconds();
+
+		spin_unlock_bh(&x->lock);
+
+		skb_reset_network_header(skb);
+
+		if (!(skb->dst = dst_pop(dst))) {
+			err = -EHOSTUNREACH;
+			goto error_nolock;
+		}
+		dst = skb->dst;
+		x = dst->xfrm;
+	} while (x && (x->props.mode != XFRM_MODE_TUNNEL));
+
+	err = 0;
+
+error_nolock:
+	return err;
+error:
+	spin_unlock_bh(&x->lock);
+	goto error_nolock;
+}
+EXPORT_SYMBOL_GPL(xfrm_output);