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Hello,
On Mon, 20 Sep 2010, Simon Horman wrote:
IPVS has a special Local forwarding mechanism that is used if the
real-server is a local IP address. Like the Route and Tunnel forwarding
mechanism Local does not allow port mapping, and thus the port of the
real-server is always set to be the same as the virtual service.
The Masq forwarding mechanism does allow port mapping, and this causes some
confusion when the real-server happens to be local.
This patch addresses this confusion by not using the Local forwarding
mechanism if the masq forwarding mechanism is requested. That is, the masq
forwarding mechanism will be used, and the real-servers may have a
different port to the virtual service.
Idea is good but there are some things to consider:
- ip_vs_nat_xmit should check the route to real server IP
but must return NF_ACCEPT instead of creating loops by
sending the packets with IP_VS_XMIT. Checks for MTU,
hard_header_len and replacing of skb_dst should be avoided
for the 'rt->rt_flags & RTCF_LOCAL' case. As result,
the packet will be DNAT-ed by IPVS and the conntrack
will be altered to expect reply from the correct local port
and then just like ip_vs_null_xmit the traffic will
reach local stack. 127.0.0.1/8 should be rejected
for the MASQ method because the output routing called
by local stack will not want to send such saddr in replies.
- We have to check if ip_vs_out is prepared to work in
LOCAL_OUT: I hope icmp_send works from this hook.
Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
---
I considered using Local for the case where the real-server and virtual
service ports are the same. However, this would require updating the
real-servers if the port of the virtual-service was changed, however
editing the forwarding mechanism of a real-server currently isn't
supported and the extra complexity for an unmeasured performance gain seems
to be at best left for another patch.
Index: nf-next-2.6/net/netfilter/ipvs/ip_vs_core.c
===================================================================
--- nf-next-2.6.orig/net/netfilter/ipvs/ip_vs_core.c 2010-09-19
20:51:30.000000000 +0900
+++ nf-next-2.6/net/netfilter/ipvs/ip_vs_core.c 2010-09-20 16:30:59.000000000
+0900
@@ -1496,6 +1496,22 @@ static struct nf_hook_ops ip_vs_ops[] __
.hooknum = NF_INET_FORWARD,
.priority = 100,
},
Double block?:
+ /* change source only for local VS/NAT */
+ {
+ .hook = ip_vs_out,
+ .owner = THIS_MODULE,
+ .pf = PF_INET,
+ .hooknum = NF_INET_LOCAL_OUT,
+ .priority = 100,
+ },
+ /* change source only for local VS/NAT */
+ {
+ .hook = ip_vs_out,
+ .owner = THIS_MODULE,
+ .pf = PF_INET,
+ .hooknum = NF_INET_LOCAL_OUT,
+ .priority = 100,
+ },
/* After packet filtering (but before ip_vs_out_icmp), catch icmp
* destined for 0.0.0.0/0, which is for incoming IPVS connections */
{
Index: nf-next-2.6/net/netfilter/ipvs/ip_vs_ctl.c
===================================================================
--- nf-next-2.6.orig/net/netfilter/ipvs/ip_vs_ctl.c 2010-09-20
15:07:27.000000000 +0900
+++ nf-next-2.6/net/netfilter/ipvs/ip_vs_ctl.c 2010-09-20 17:45:46.000000000
+0900
@@ -766,7 +766,7 @@ ip_vs_zero_stats(struct ip_vs_stats *sta
* Update a destination in the given service
*/
static void
'_' in __ip_vs_update_dest was lost?:
-__ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest,
+_ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest,
struct ip_vs_dest_user_kern *udest, int add)
{
int conn_flags;
@@ -777,18 +777,22 @@ __ip_vs_update_dest(struct ip_vs_service
conn_flags |= IP_VS_CONN_F_INACTIVE;
/* check if local node and update the flags */
I think, it should work for svc->fwmark too, eg.
consolidating traffic for many virtual IPs to single
listening socket.
+ if ((conn_flags & IP_VS_CONN_F_FWD_MASK) != IP_VS_CONN_F_MASQ ||
+ svc->fwmark) {
#ifdef CONFIG_IP_VS_IPV6
- if (svc->af == AF_INET6) {
- if (__ip_vs_addr_is_local_v6(&udest->addr.in6)) {
- conn_flags = (conn_flags & ~IP_VS_CONN_F_FWD_MASK)
- | IP_VS_CONN_F_LOCALNODE;
- }
- } else
+ if (svc->af == AF_INET6) {
+ if (__ip_vs_addr_is_local_v6(&udest->addr.in6)) {
+ conn_flags = (conn_flags &
+ ~IP_VS_CONN_F_FWD_MASK) |
+ IP_VS_CONN_F_LOCALNODE;
+ }
+ } else
#endif
if (inet_addr_type(&init_net, udest->addr.ip) == RTN_LOCAL) {
conn_flags = (conn_flags & ~IP_VS_CONN_F_FWD_MASK)
| IP_VS_CONN_F_LOCALNODE;
}
+ }
/* set the IP_VS_CONN_F_NOOUTPUT flag if not masquerading/NAT */
if ((conn_flags & IP_VS_CONN_F_FWD_MASK) != IP_VS_CONN_F_MASQ) {
Regards
--
Julian Anastasov <ja@xxxxxx>
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