[lvs-users] FWMARKs and persistence

Simon Horman horms at verge.net.au
Mon May 11 05:57:58 BST 2009


A fix for this problem has been accepted by Dave Miller and has
subsequently been merged into Linus's kernel tree. I expect that
It will be include in 2.6.30-rc6 and subsequently 2.6.30.

I encourage any interested parties to test this change so that we have a
better chance of spotting any problems before 2.6.30 is finalised.

For reference, the change accepted by Dave is below:


From: Simon Horman <horms at verge.net.au>

ipvs: Fix IPv4 FWMARK virtual services

This fixes the use of fwmarks to denote IPv4 virtual services
which was unfortunately broken as a result of the integration
of IPv6 support into IPVS, which was included in 2.6.28.

The problem arises because fwmarks are stored in the 4th octet
of a union nf_inet_addr .all, however in the case of IPv4 only
the first octet, corresponding to .ip, is assigned and compared.

In other words, using .all = { 0, 0, 0, htonl(svc->fwmark) always
results in a value of 0 (32bits) being stored for IPv4. This means
that one fwmark can be used, as it ends up being mapped to 0, but things
break down when multiple fwmarks are used, as they all end up being mapped
to 0.

As fwmarks are 32bits a reasonable fix seems to be to just store the fwmark
in .ip, and comparing and storing .ip when fwmarks are used.

This patch makes the assumption that in calls to ip_vs_ct_in_get()
and ip_vs_sched_persist() if the proto parameter is IPPROTO_IP then
we are dealing with an fwmark. I believe this is valid as ip_vs_in()
does fairly strict filtering on the protocol and IPPROTO_IP should
not be used in these calls unless explicitly passed when making
these calls for fwmarks in ip_vs_sched_persist().

Tested-by: Fabien Duchêne <fabien.duchene at student.uclouvain.be>
Cc: Joseph Mack NA3T <jmack at wm7d.net>
Cc: Julius Volz <julius.volz at gmail.com>
Signed-off-by: Simon Horman <horms at verge.net.au>
Signed-off-by: David S. Miller <davem at davemloft.net>

diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
index 60aba45..77bfdfe 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -260,7 +260,10 @@ struct ip_vs_conn *ip_vs_ct_in_get
 	list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 		if (cp->af == af &&
 		    ip_vs_addr_equal(af, s_addr, &cp->caddr) &&
-		    ip_vs_addr_equal(af, d_addr, &cp->vaddr) &&
+		    /* protocol should only be IPPROTO_IP if
+		     * d_addr is a fwmark */
+		    ip_vs_addr_equal(protocol == IPPROTO_IP ? AF_UNSPEC : af,
+		                     d_addr, &cp->vaddr) &&
 		    s_port == cp->cport && d_port == cp->vport &&
 		    cp->flags & IP_VS_CONN_F_TEMPLATE &&
 		    protocol == cp->protocol) {
@@ -698,7 +701,9 @@ ip_vs_conn_new(int af, int proto, const union nf_inet_addr *caddr, __be16 cport,
 	cp->cport	   = cport;
 	ip_vs_addr_copy(af, &cp->vaddr, vaddr);
 	cp->vport	   = vport;
-	ip_vs_addr_copy(af, &cp->daddr, daddr);
+	/* proto should only be IPPROTO_IP if d_addr is a fwmark */
+	ip_vs_addr_copy(proto == IPPROTO_IP ? AF_UNSPEC : af,
+			&cp->daddr, daddr);
 	cp->dport          = dport;
 	cp->flags	   = flags;
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index cb3e031..8dddb17 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -278,7 +278,7 @@ ip_vs_sched_persist(struct ip_vs_service *svc,
 		if (svc->fwmark) {
 			union nf_inet_addr fwmark = {
-				.all = { 0, 0, 0, htonl(svc->fwmark) }
+				.ip = htonl(svc->fwmark)
 			ct = ip_vs_ct_in_get(svc->af, IPPROTO_IP, &snet, 0,
@@ -306,7 +306,7 @@ ip_vs_sched_persist(struct ip_vs_service *svc,
 			if (svc->fwmark) {
 				union nf_inet_addr fwmark = {
-					.all = { 0, 0, 0, htonl(svc->fwmark) }
+					.ip = htonl(svc->fwmark)
 				ct = ip_vs_conn_new(svc->af, IPPROTO_IP,

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