v4.19.13 snapshot.
diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
new file mode 100644
index 0000000..be980c1
--- /dev/null
+++ b/net/ipv4/xfrm4_output.c
@@ -0,0 +1,116 @@
+/*
+ * 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)));
+
+#ifdef CONFIG_NETFILTER
+ IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
+#endif
+
+ 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);
+}