From: Brett A C Sheffield (Librecast) <bacs@librecast.net>
Date: Wed, 2 Jul 2025 11:41:14 +0000 (+0200)
Subject: Revert "ipv6: save dontfrag in cork"
X-Git-Tag: v5.10.240~137
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3881c1936af24f997ef46ad38c55a742c7fe421b;p=thirdparty%2Fkernel%2Fstable.git

Revert "ipv6: save dontfrag in cork"

This reverts commit 29533d1a54b8de5aaf8c4aa6790dc67d5c14fba5 which is
commit a18dfa9925b9ef6107ea3aa5814ca3c704d34a8a upstream.

A regression was introduced when backporting this to the stable kernels
without applying previous commits in this series.

When sending IPv6 UDP packets larger than MTU, EMSGSIZE was returned
instead of fragmenting the packets as expected.

As there is no compelling reason for this commit to be present in the
stable kernels it should be reverted.

Signed-off-by: Brett A C Sheffield <bacs@librecast.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 89b3527e03675..d758c131ed5e1 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -189,7 +189,6 @@ struct inet6_cork {
 	struct ipv6_txoptions *opt;
 	u8 hop_limit;
 	u8 tclass;
-	u8 dontfrag:1;
 };
 
 /**
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index f024d89cb0f81..426330b8dfa47 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1416,7 +1416,6 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
 	cork->fl.u.ip6 = *fl6;
 	v6_cork->hop_limit = ipc6->hlimit;
 	v6_cork->tclass = ipc6->tclass;
-	v6_cork->dontfrag = ipc6->dontfrag;
 	if (rt->dst.flags & DST_XFRM_TUNNEL)
 		mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
 		      READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
@@ -1451,7 +1450,7 @@ static int __ip6_append_data(struct sock *sk,
 			     int getfrag(void *from, char *to, int offset,
 					 int len, int odd, struct sk_buff *skb),
 			     void *from, size_t length, int transhdrlen,
-			     unsigned int flags)
+			     unsigned int flags, struct ipcm6_cookie *ipc6)
 {
 	struct sk_buff *skb, *skb_prev = NULL;
 	unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu;
@@ -1508,7 +1507,7 @@ static int __ip6_append_data(struct sock *sk,
 	if (headersize + transhdrlen > mtu)
 		goto emsgsize;
 
-	if (cork->length + length > mtu - headersize && v6_cork->dontfrag &&
+	if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
 	    (sk->sk_protocol == IPPROTO_UDP ||
 	     sk->sk_protocol == IPPROTO_RAW)) {
 		ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
@@ -1826,7 +1825,7 @@ int ip6_append_data(struct sock *sk,
 
 	return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base,
 				 &np->cork, sk_page_frag(sk), getfrag,
-				 from, length, transhdrlen, flags);
+				 from, length, transhdrlen, flags, ipc6);
 }
 EXPORT_SYMBOL_GPL(ip6_append_data);
 
@@ -2021,7 +2020,7 @@ struct sk_buff *ip6_make_skb(struct sock *sk,
 	err = __ip6_append_data(sk, fl6, &queue, &cork->base, &v6_cork,
 				&current->task_frag, getfrag, from,
 				length + exthdrlen, transhdrlen + exthdrlen,
-				flags);
+				flags, ipc6);
 	if (err) {
 		__ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);
 		return ERR_PTR(err);