From: Ben Hutchings <ben@decadent.org.uk>
Date: Thu, 16 Nov 2017 21:00:59 +0000 (+0000)
Subject: netfilter: nat: Avoid ABI change in 4.13.13
X-Git-Tag: archive/raspbian/4.15.4-1+rpi1~1^2^2^2~1
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=ec854b1fcaf63b77f54acbd7685ea3525023836c;p=linux.git

netfilter: nat: Avoid ABI change in 4.13.13

Commit e1bf1687740c ("netfilter: nat: Revert "netfilter: nat: convert
nat bysrc hash to rhashtable") changed the type of
nf_conn::nat_bysource.  Thankfully the two types are the same size,
and nothing outside of nf_nat_core touches this field directly.  Hide
the change from genksyms but add compile-time assertions to make sure
that this isn't an ABI change.


Gbp-Pq: Topic debian
Gbp-Pq: Name netfilter-nat-avoid-abi-change-in-4.13.13.patch
---

diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index a7c2cee3957..3fa5220521e 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -17,6 +17,7 @@
 #include <linux/bitops.h>
 #include <linux/compiler.h>
 #include <linux/atomic.h>
+#include <linux/rhashtable.h>
 
 #include <linux/netfilter/nf_conntrack_tcp.h>
 #include <linux/netfilter/nf_conntrack_dccp.h>
@@ -82,7 +83,11 @@ struct nf_conn {
 	possible_net_t ct_net;
 
 #if IS_ENABLED(CONFIG_NF_NAT)
+#ifndef __GENKSYMS__
 	struct hlist_node	nat_bysource;
+#else
+	struct rhlist_head	nat_bysource;
+#endif
 #endif
 	/* all members below initialized via memset */
 	u8 __nfct_init_offset[0];
diff --git a/include/net/netfilter/nf_nat.h b/include/net/netfilter/nf_nat.h
index b71701302e6..05c82a1a426 100644
--- a/include/net/netfilter/nf_nat.h
+++ b/include/net/netfilter/nf_nat.h
@@ -1,5 +1,6 @@
 #ifndef _NF_NAT_H
 #define _NF_NAT_H
+#include <linux/rhashtable.h>
 #include <linux/netfilter_ipv4.h>
 #include <linux/netfilter/nf_nat.h>
 #include <net/netfilter/nf_conntrack_tuple.h>
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index 2fb80a4bfb3..2a46bc1aee8 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -796,6 +796,11 @@ static int __init nf_nat_init(void)
 {
 	int ret;
 
+	/* bwh: Assert that nat_bysource hasn't changed size or alignment */
+	BUILD_BUG_ON(sizeof(struct hlist_node) != sizeof(struct rhlist_head));
+	BUILD_BUG_ON(__alignof__(struct hlist_node) !=
+		     __alignof__(struct rhlist_head));
+
 	/* Leave them the same for the moment. */
 	nf_nat_htable_size = nf_conntrack_htable_size;