ipvs: API change to avoid rescan of IPv6 exthdr

Reduce the number of times we scan/skip the IPv6 exthdrs.

This patch contains a lot of API changes.  This is done, to avoid
repeating the scan of finding the IPv6 headers, via ipv6_find_hdr(),
which is called by ip_vs_fill_iph_skb().

Finding the IPv6 headers is done as early as possible, and passed on
as a pointer "struct ip_vs_iphdr *" to the affected functions.

This patch reduce/removes 19 calls to ip_vs_fill_iph_skb().

Notice, I have choosen, not to change the API of function
pointer "(*schedule)" (in struct ip_vs_scheduler) as it can be
used by external schedulers, via {un,}register_ip_vs_scheduler.
Only 4 out of 10 schedulers use info from ip_vs_iphdr*, and when
they do, they are only interested in iph->{s,d}addr.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 16 insertions, 25 deletions

diff --git a/net/netfilter/ipvs/ip_vs_proto_udp.c b/net/netfilter/ipvs/ip_vs_proto_udp.c
index d6f4eeec8b71..503a842c90d2 100644
--- a/net/netfilter/ipvs/ip_vs_proto_udp.c
+++ b/net/netfilter/ipvs/ip_vs_proto_udp.c
@@ -30,23 +30,22 @@
 
 static int
 udp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_proto_data *pd,
-		  int *verdict, struct ip_vs_conn **cpp)
+		  int *verdict, struct ip_vs_conn **cpp,
+		  struct ip_vs_iphdr *iph)
 {
 	struct net *net;
 	struct ip_vs_service *svc;
 	struct udphdr _udph, *uh;
-	struct ip_vs_iphdr iph;
 
-	ip_vs_fill_iph_skb(af, skb, &iph);
-
-	uh = skb_header_pointer(skb, iph.len, sizeof(_udph), &_udph);
+	/* IPv6 fragments, only first fragment will hit this */
+	uh = skb_header_pointer(skb, iph->len, sizeof(_udph), &_udph);
 	if (uh == NULL) {
 		*verdict = NF_DROP;
 		return 0;
 	}
 	net = skb_net(skb);
-	svc = ip_vs_service_get(net, af, skb->mark, iph.protocol,
-				&iph.daddr, uh->dest);
+	svc = ip_vs_service_get(net, af, skb->mark, iph->protocol,
+				&iph->daddr, uh->dest);
 	if (svc) {
 		int ignored;
 
@@ -64,10 +63,10 @@ udp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_proto_data *pd,
 		 * Let the virtual server select a real server for the
 		 * incoming connection, and create a connection entry.
 		 */
-		*cpp = ip_vs_schedule(svc, skb, pd, &ignored);
+		*cpp = ip_vs_schedule(svc, skb, pd, &ignored, iph);
 		if (!*cpp && ignored <= 0) {
 			if (!ignored)
-				*verdict = ip_vs_leave(svc, skb, pd);
+				*verdict = ip_vs_leave(svc, skb, pd, iph);
 			else {
 				ip_vs_service_put(svc);
 				*verdict = NF_DROP;
@@ -125,20 +124,16 @@ udp_partial_csum_update(int af, struct udphdr *uhdr,
 
 
 static int
-udp_snat_handler(struct sk_buff *skb,
-		 struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
+udp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
+		 struct ip_vs_conn *cp, struct ip_vs_iphdr *iph)
 {
 	struct udphdr *udph;
-	unsigned int udphoff;
+	unsigned int udphoff = iph->len;
 	int oldlen;
 	int payload_csum = 0;
 
-	struct ip_vs_iphdr iph;
-	ip_vs_fill_iph_skb(cp->af, skb, &iph);
-	udphoff = iph.len;
-
 #ifdef CONFIG_IP_VS_IPV6
-	if (cp->af == AF_INET6 && iph.fragoffs)
+	if (cp->af == AF_INET6 && iph->fragoffs)
 		return 1;
 #endif
 	oldlen = skb->len - udphoff;
@@ -212,20 +207,16 @@ udp_snat_handler(struct sk_buff *skb,
 
 
 static int
-udp_dnat_handler(struct sk_buff *skb,
-		 struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
+udp_dnat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
+		 struct ip_vs_conn *cp, struct ip_vs_iphdr *iph)
 {
 	struct udphdr *udph;
-	unsigned int udphoff;
+	unsigned int udphoff = iph->len;
 	int oldlen;
 	int payload_csum = 0;
 
-	struct ip_vs_iphdr iph;
-	ip_vs_fill_iph_skb(cp->af, skb, &iph);
-	udphoff = iph.len;
-
 #ifdef CONFIG_IP_VS_IPV6
-	if (cp->af == AF_INET6 && iph.fragoffs)
+	if (cp->af == AF_INET6 && iph->fragoffs)
 		return 1;
 #endif
 	oldlen = skb->len - udphoff;