1 files changed, 53 insertions, 102 deletions

diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 8755a3079d0f..512bdaf13699 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -1,12 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
  * Copyright (C) 2002 USAGI/WIDE Project
  * 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>
@@ -20,30 +16,7 @@
 #include <net/ip6_route.h>
 #include <net/xfrm.h>
 
-int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
-			  u8 **prevhdr)
-{
-	return ip6_find_1stfragopt(skb, prevhdr);
-}
-
-EXPORT_SYMBOL(xfrm6_find_1stfragopt);
-
-static int xfrm6_local_dontfrag(struct sk_buff *skb)
-{
-	int proto;
-	struct sock *sk = skb->sk;
-
-	if (sk) {
-		proto = sk->sk_protocol;
-
-		if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
-			return inet6_sk(sk)->dontfrag;
-	}
-
-	return 0;
-}
-
-static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
+void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
 {
 	struct flowi6 fl6;
 	struct sock *sk = skb->sk;
@@ -54,108 +27,86 @@ static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
 	ipv6_local_rxpmtu(sk, &fl6, mtu);
 }
 
-static void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
+void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
 {
 	struct flowi6 fl6;
+	const struct ipv6hdr *hdr;
 	struct sock *sk = skb->sk;
 
+	hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
 	fl6.fl6_dport = inet_sk(sk)->inet_dport;
-	fl6.daddr = ipv6_hdr(skb)->daddr;
+	fl6.daddr = hdr->daddr;
 
 	ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
 }
 
-static int xfrm6_tunnel_check_size(struct sk_buff *skb)
+static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	int mtu, ret = 0;
-	struct dst_entry *dst = skb_dst(skb);
-
-	mtu = dst_mtu(dst);
-	if (mtu < IPV6_MIN_MTU)
-		mtu = IPV6_MIN_MTU;
-
-	if (!skb->local_df && skb->len > mtu) {
-		skb->dev = dst->dev;
-
-		if (xfrm6_local_dontfrag(skb))
-			xfrm6_local_rxpmtu(skb, mtu);
-		else if (skb->sk)
-			xfrm6_local_error(skb, mtu);
-		else
-			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
-		ret = -EMSGSIZE;
-	}
-
-	return ret;
+	return xfrm_output(sk, skb);
 }
 
-int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
+static int xfrm6_noneed_fragment(struct sk_buff *skb)
 {
-	int err;
-
-	err = xfrm6_tunnel_check_size(skb);
-	if (err)
-		return err;
-
-	XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
-
-	return xfrm6_extract_header(skb);
+	struct frag_hdr *fh;
+	u8 prevhdr = ipv6_hdr(skb)->nexthdr;
+
+	if (prevhdr != NEXTHDR_FRAGMENT)
+		return 0;
+	fh = (struct frag_hdr *)(skb->data + sizeof(struct ipv6hdr));
+	if (fh->nexthdr == NEXTHDR_ESP || fh->nexthdr == NEXTHDR_AUTH)
+		return 1;
+	return 0;
 }
 
-int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
+static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	int err;
-
-	err = xfrm_inner_extract_output(x, skb);
-	if (err)
-		return err;
+	struct dst_entry *dst = skb_dst(skb);
+	struct xfrm_state *x = dst->xfrm;
+	unsigned int mtu;
+	bool toobig;
 
-	memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 #ifdef CONFIG_NETFILTER
-	IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
+	if (!x) {
+		IP6CB(skb)->flags |= IP6SKB_REROUTED;
+		return dst_output(net, sk, skb);
+	}
 #endif
 
-	skb->protocol = htons(ETH_P_IPV6);
-	skb->local_df = 1;
-
-	return x->outer_mode->output2(x, skb);
-}
-EXPORT_SYMBOL(xfrm6_prepare_output);
-
-int xfrm6_output_finish(struct sk_buff *skb)
-{
-#ifdef CONFIG_NETFILTER
-	IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
-#endif
+	if (x->props.mode != XFRM_MODE_TUNNEL)
+		goto skip_frag;
 
-	skb->protocol = htons(ETH_P_IPV6);
-	return xfrm_output(skb);
-}
+	if (skb->protocol == htons(ETH_P_IPV6))
+		mtu = ip6_skb_dst_mtu(skb);
+	else
+		mtu = dst_mtu(skb_dst(skb));
 
-static int __xfrm6_output(struct sk_buff *skb)
-{
-	struct dst_entry *dst = skb_dst(skb);
-	struct xfrm_state *x = dst->xfrm;
-	int mtu = ip6_skb_dst_mtu(skb);
+	toobig = skb->len > mtu && !skb_is_gso(skb);
 
-	if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
+	if (toobig && xfrm6_local_dontfrag(sk)) {
 		xfrm6_local_rxpmtu(skb, mtu);
+		kfree_skb(skb);
 		return -EMSGSIZE;
-	} else if (!skb->local_df && skb->len > mtu && skb->sk) {
-		xfrm6_local_error(skb, mtu);
+	} else if (toobig && xfrm6_noneed_fragment(skb)) {
+		skb->ignore_df = 1;
+		goto skip_frag;
+	} else if (!skb->ignore_df && toobig && sk) {
+		xfrm_local_error(skb, mtu);
+		kfree_skb(skb);
 		return -EMSGSIZE;
 	}
 
-	if (x->props.mode == XFRM_MODE_TUNNEL &&
-	    ((skb->len > mtu && !skb_is_gso(skb)) ||
-		dst_allfrag(skb_dst(skb)))) {
-			return ip6_fragment(skb, x->outer_mode->afinfo->output_finish);
-	}
-	return x->outer_mode->afinfo->output_finish(skb);
+	if (toobig)
+		return ip6_fragment(net, sk, skb,
+				    __xfrm6_output_finish);
+
+skip_frag:
+	return xfrm_output(sk, skb);
 }
 
-int xfrm6_output(struct sk_buff *skb)
+int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL,
-		       skb_dst(skb)->dev, __xfrm6_output);
+	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
+			    net, sk, skb,  skb->dev, skb_dst_dev(skb),
+			    __xfrm6_output,
+			    !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 }