From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Mon, 6 May 2024 03:02:30 +0200
Subject: Adding upstream version 4.19.249.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 net/ipv4/xfrm4_output.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 net/ipv4/xfrm4_output.c

(limited to 'net/ipv4/xfrm4_output.c')

diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
new file mode 100644
index 000000000..510d2ec4c
--- /dev/null
+++ b/net/ipv4/xfrm4_output.c
@@ -0,0 +1,114 @@
+/*
+ * 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;
+
+	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
+		goto out;
+
+	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
+		goto out;
+
+	mtu = dst_mtu(skb_dst(skb));
+	if ((!skb_is_gso(skb) && skb->len > mtu) ||
+	    (skb_is_gso(skb) &&
+	     !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
+		skb->protocol = htons(ETH_P_IP);
+
+		if (skb->sk)
+			xfrm_local_error(skb, mtu);
+		else
+			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;
+
+	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
+	skb->protocol = htons(ETH_P_IP);
+
+	return x->outer_mode->output2(x, skb);
+}
+EXPORT_SYMBOL(xfrm4_prepare_output);
+
+int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
+{
+	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+
+	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
+
+	return xfrm_output(sk, skb);
+}
+
+static int __xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct xfrm_state *x = skb_dst(skb)->xfrm;
+
+#ifdef CONFIG_NETFILTER
+	if (!x) {
+		IPCB(skb)->flags |= IPSKB_REROUTED;
+		return dst_output(net, sk, skb);
+	}
+#endif
+
+	return x->outer_mode->afinfo->output_finish(sk, skb);
+}
+
+int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
+			    net, sk, skb, NULL, skb_dst(skb)->dev,
+			    __xfrm4_output,
+			    !(IPCB(skb)->flags & IPSKB_REROUTED));
+}
+
+void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
+{
+	struct iphdr *hdr;
+
+	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
+	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
+		       inet_sk(skb->sk)->inet_dport, mtu);
+}
-- 
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