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-rw-r--r--include/net/flow.h5
-rw-r--r--net/ipv4/ip_output.c21
2 files changed, 21 insertions, 5 deletions
diff --git a/include/net/flow.h b/include/net/flow.h
index a09447749e2d..9192d690b562 100644
--- a/include/net/flow.h
+++ b/include/net/flow.h
@@ -59,8 +59,11 @@ struct flowi4 {
 #define flowi4_proto		__fl_common.flowic_proto
 #define flowi4_flags		__fl_common.flowic_flags
 #define flowi4_secid		__fl_common.flowic_secid
-	__be32			daddr;
+
+	/* (saddr,daddr) must be grouped, same order as in IP header */
 	__be32			saddr;
+	__be32			daddr;
+
 	union flowi_uli		uli;
 #define fl4_sport		uli.ports.sport
 #define fl4_dport		uli.ports.dport
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 0bc95f3977d2..0d5e5672f3d1 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -319,6 +319,20 @@ int ip_output(struct sk_buff *skb)
 			    !(IPCB(skb)->flags & IPSKB_REROUTED));
 }
 
+/*
+ * copy saddr and daddr, possibly using 64bit load/stores
+ * Equivalent to :
+ *   iph->saddr = fl4->saddr;
+ *   iph->daddr = fl4->daddr;
+ */
+static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4)
+{
+	BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) !=
+		     offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr));
+	memcpy(&iph->saddr, &fl4->saddr,
+	       sizeof(fl4->saddr) + sizeof(fl4->daddr));
+}
+
 int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl)
 {
 	struct sock *sk = skb->sk;
@@ -381,8 +395,8 @@ packet_routed:
 		iph->frag_off = 0;
 	iph->ttl      = ip_select_ttl(inet, &rt->dst);
 	iph->protocol = sk->sk_protocol;
-	iph->saddr    = fl4->saddr;
-	iph->daddr    = fl4->daddr;
+	ip_copy_addrs(iph, fl4);
+
 	/* Transport layer set skb->h.foo itself. */
 
 	if (inet_opt && inet_opt->opt.optlen) {
@@ -1337,8 +1351,7 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
 	ip_select_ident(iph, &rt->dst, sk);
 	iph->ttl = ttl;
 	iph->protocol = sk->sk_protocol;
-	iph->saddr = fl4->saddr;
-	iph->daddr = fl4->daddr;
+	ip_copy_addrs(iph, fl4);
 
 	if (opt) {
 		iph->ihl += opt->optlen>>2;