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Hello,
On Mon, 20 Sep 2010, Hans Schillstrom wrote:
Tunnel mode for IPv6 doesn't work.
IPv6 encapsulation uses a bad source address for the tunnel.
i.e. VIP will be used as local-addr and encap. dst addr.
Decapsulation will not accept this.
Reading http://kb.linuxvirtualserver.org/wiki/IPv6_load_balancing
may be TUN for IPv6 is not fully tested. Using VIP as saddr
looks like spoofing because it can be configured on real server
too. CC-ed Julius Volz to comment about using cp->vaddr as
source for tunnel. May be it was used because rt6i_src is zero.
Example
LVS (eth1 2003::2:0:1/96, VIP 2003::2:0:100)
(eth0 2003::1:0:1/96)
RS (ethX 2003::1:0:5/96)
tcpdump
2003::2:0:100 > 2003::1:0:5:
IP6 (hlim 63, next-header TCP (6) payload length: 40)
2003::3:0:10.50991 > 2003::2:0:100.http: Flags [S], cksum 0x7312
(correct), seq 3006460279, win 5760, options [mss 1440,sackOK,TS val
1904932 ecr 0,nop,wscale 3], length 0
In Linux IPv6 impl. you can't have a tunnel with an any cast address
receiving packets (I have not tried to interpret RFC 2473)
To have receive capabilities the tunnel must have:
- Local address set as multicast addr or an unicast addr
- Remote address set as an unicast addr.
- Loop back addres or Link local address are not allowed.
Yes, the tunnel device has many options for assigning
local/remote addresses depending on traffic direction but
for IPVS we use only unicast->unicast traffic. We even
do not configure any tunnel parameters in real server
for IPv4, just adding some address is enough, eg. 0.0.0.0.
New kernels will need {all,default}/rp_filter=0 together
with tunl*/rp_filter=0 because MAX(all,dev}/rp_filter is used.
This causes us to setup a tunnel in the Real Server with the
LVS as the remote address, here you can't use the VIP address since it's
used inside the tunnel.
Solution
Use outgoing interface IPv6 address (match against the destination).
i.e. use ipv6_dev_get_saddr(...) to set the source address of the
encapsulated package.
However this lookup cost some cpu time to do, so there is some speed
enhancements to this patch
The dst caching should work as for IPv4.
To properly cache for IPv6 we need to add new fields in
struct ip_vs_dest: dst_cookie, dst_saddr. We can do it just like
in net/ipv6/ip6_tunnel.c:ip6_tnl_dst_check(). ip6_tnl_xmit2()
is a good example for IPv6 tunneling.
a) Cache the result
b) Static configuration i.e. used a static configured address
(since the tunnel in RS use a static address remote address)
Here follows the patch without any enhancements mention above.
Signed-off-by: hans.schillstrom@xxxxxxxxxxxx
---
--- linux-2.6.35.next/net/netfilter/ipvs/ip_vs_xmit.c 2010-08-13
12:18:12.000000000 +0200
+++ linux-2.6.35.x/net/netfilter/ipvs/ip_vs_xmit.c 2010-09-20
11:38:50.000000000 +0200
@@ -688,10 +702,25 @@
rt = __ip_vs_get_out_rt_v6(cp);
if (!rt)
goto tx_error_icmp;
tdev = rt->dst.dev;
+ /* Lookup source address for the tunnel */
+ if (likely(ipv6_addr_any(&rt->rt6i_src.addr))) {
+ struct net *net = dev_net(skb->dev);
+ int err = ipv6_dev_get_saddr(net, tdev,
+ &rt->rt6i_dst.addr,
+ 0,
+ &rt->rt6i_src.addr);
After looking at ipv6/ files I'm still not sure
if ip6_route_output() returns valid rt6i_src in all cases.
May be rt6i_src is filled only when CONFIG_IPV6_SUBTREES
is defined.
So, may be your approach to use ipv6_dev_get_saddr
is correct but I prefer a version that caches the routing
results. So, I created a new patch for testing. But I don't
have IPv6 setup to test it. Can you confirm that with this
patch applied the message "new dst %pI6, src %pI6" shows
correct results and that it does not appear for every packet.
The idea is to see this message only once if the dst caching
works for us. Patch is appended.
+ /* RFC 2473 Ch 8. IPv6 Tunnel Error Processing and
Reporting
+ * Both tunnel header and tunnel packet problems are
reported
+ * to the tunnel entry-point node.
+ */
+ if (err) {
+ goto tx_error_icmp;
+ }
+ }
mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
/* TODO IPv6: do we need this check in IPv6? */
if (mtu < 1280) {
dst_release(&rt->dst);
@@ -747,11 +776,11 @@
iph->payload_len = old_iph->payload_len;
be16_add_cpu(&iph->payload_len, sizeof(*old_iph));
iph->priority = old_iph->priority;
memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl));
iph->daddr = rt->rt6i_dst.addr;
- iph->saddr = cp->vaddr.in6; /*
rt->rt6i_src.addr; */
+ iph->saddr = rt->rt6i_src.addr;
iph->hop_limit = old_iph->hop_limit;
/* Another hack: avoid icmp_send in ip_fragment */
skb->local_df = 1;
--
Signed-off-by: Julian Anastasov <ja@xxxxxx>
---
diff -urp net-next-2.6-e548833-nfct_snat_reroute/linux/include/net/ip_vs.h
linux/include/net/ip_vs.h
--- net-next-2.6-e548833-nfct_snat_reroute/linux/include/net/ip_vs.h
2010-09-16 09:03:48.000000000 +0300
+++ linux/include/net/ip_vs.h 2010-09-22 10:50:18.548963467 +0300
@@ -509,6 +509,10 @@ struct ip_vs_dest {
spinlock_t dst_lock; /* lock of dst_cache */
struct dst_entry *dst_cache; /* destination cache entry */
u32 dst_rtos; /* RT_TOS(tos) for dst */
+ u32 dst_cookie;
+#ifdef CONFIG_IP_VS_IPV6
+ struct in6_addr dst_saddr;
+#endif
/* for virtual service */
struct ip_vs_service *svc; /* service it belongs to */
diff -urp
net-next-2.6-e548833-nfct_snat_reroute/linux/net/netfilter/ipvs/ip_vs_xmit.c
linux/net/netfilter/ipvs/ip_vs_xmit.c
---
net-next-2.6-e548833-nfct_snat_reroute/linux/net/netfilter/ipvs/ip_vs_xmit.c
2010-09-16 09:02:25.000000000 +0300
+++ linux/net/netfilter/ipvs/ip_vs_xmit.c 2010-09-22 16:29:43.271964521
+0300
@@ -26,6 +26,7 @@
#include <net/route.h> /* for ip_route_output */
#include <net/ipv6.h>
#include <net/ip6_route.h>
+#include <net/addrconf.h>
#include <linux/icmpv6.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
@@ -37,26 +38,27 @@
* Destination cache to speed up outgoing route lookup
*/
static inline void
-__ip_vs_dst_set(struct ip_vs_dest *dest, u32 rtos, struct dst_entry *dst)
+__ip_vs_dst_set(struct ip_vs_dest *dest, u32 rtos, struct dst_entry *dst,
+ u32 dst_cookie)
{
struct dst_entry *old_dst;
old_dst = dest->dst_cache;
dest->dst_cache = dst;
dest->dst_rtos = rtos;
+ dest->dst_cookie = dst_cookie;
dst_release(old_dst);
}
static inline struct dst_entry *
-__ip_vs_dst_check(struct ip_vs_dest *dest, u32 rtos, u32 cookie)
+__ip_vs_dst_check(struct ip_vs_dest *dest, u32 rtos)
{
struct dst_entry *dst = dest->dst_cache;
if (!dst)
return NULL;
- if ((dst->obsolete
- || (dest->af == AF_INET && rtos != dest->dst_rtos)) &&
- dst->ops->check(dst, cookie) == NULL) {
+ if ((dst->obsolete || rtos != dest->dst_rtos) &&
+ dst->ops->check(dst, dest->dst_cookie) == NULL) {
dest->dst_cache = NULL;
dst_release(dst);
return NULL;
@@ -66,15 +68,16 @@ __ip_vs_dst_check(struct ip_vs_dest *des
}
static struct rtable *
-__ip_vs_get_out_rt(struct ip_vs_conn *cp, u32 rtos)
+__ip_vs_get_out_rt(struct sk_buff *skb, struct ip_vs_conn *cp, u32 rtos)
{
+ struct net *net = dev_net(skb->dev);
struct rtable *rt; /* Route to the other host */
struct ip_vs_dest *dest = cp->dest;
if (dest) {
spin_lock(&dest->dst_lock);
if (!(rt = (struct rtable *)
- __ip_vs_dst_check(dest, rtos, 0))) {
+ __ip_vs_dst_check(dest, rtos))) {
struct flowi fl = {
.oif = 0,
.nl_u = {
@@ -84,13 +87,13 @@ __ip_vs_get_out_rt(struct ip_vs_conn *cp
.tos = rtos, } },
};
- if (ip_route_output_key(&init_net, &rt, &fl)) {
+ if (ip_route_output_key(net, &rt, &fl)) {
spin_unlock(&dest->dst_lock);
IP_VS_DBG_RL("ip_route_output error, dest:
%pI4\n",
&dest->addr.ip);
return NULL;
}
- __ip_vs_dst_set(dest, rtos, dst_clone(&rt->dst));
+ __ip_vs_dst_set(dest, rtos, dst_clone(&rt->dst), 0);
IP_VS_DBG(10, "new dst %pI4, refcnt=%d, rtos=%X\n",
&dest->addr.ip,
atomic_read(&rt->dst.__refcnt), rtos);
@@ -106,7 +109,7 @@ __ip_vs_get_out_rt(struct ip_vs_conn *cp
.tos = rtos, } },
};
- if (ip_route_output_key(&init_net, &rt, &fl)) {
+ if (ip_route_output_key(net, &rt, &fl)) {
IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n",
&cp->daddr.ip);
return NULL;
@@ -117,62 +120,79 @@ __ip_vs_get_out_rt(struct ip_vs_conn *cp
}
#ifdef CONFIG_IP_VS_IPV6
+
+static struct dst_entry *
+__ip_vs_route_output_v6(struct net *net, struct in6_addr *daddr,
+ struct in6_addr *ret_saddr, int do_xfrm)
+{
+ struct dst_entry *dst;
+ struct flowi fl = {
+ .oif = 0,
+ .nl_u = {
+ .ip6_u = {
+ .daddr = *daddr,
+ },
+ },
+ };
+
+ dst = ip6_route_output(net, NULL, &fl);
+ if (dst->error)
+ goto out_err;
+ if (!ret_saddr)
+ return dst;
+ if (ipv6_addr_any(&fl.fl6_src) &&
+ ipv6_dev_get_saddr(net, ip6_dst_idev(dst)->dev,
+ &fl.fl6_dst, 0, &fl.fl6_src) < 0)
+ goto out_err;
+ if (do_xfrm && xfrm_lookup(net, &dst, &fl, NULL, 0) < 0)
+ goto out_err;
+ ipv6_addr_copy(ret_saddr, &fl.fl6_src);
+ return dst;
+
+out_err:
+ dst_release(dst);
+ IP_VS_DBG_RL("ip6_route_output error, dest: %pI6\n", daddr);
+ return NULL;
+}
+
static struct rt6_info *
-__ip_vs_get_out_rt_v6(struct ip_vs_conn *cp)
+__ip_vs_get_out_rt_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
+ struct in6_addr *ret_saddr, int do_xfrm)
{
+ struct net *net = dev_net(skb->dev);
struct rt6_info *rt; /* Route to the other host */
struct ip_vs_dest *dest = cp->dest;
+ struct dst_entry *dst;
if (dest) {
spin_lock(&dest->dst_lock);
- rt = (struct rt6_info *)__ip_vs_dst_check(dest, 0, 0);
+ rt = (struct rt6_info *)__ip_vs_dst_check(dest, 0);
if (!rt) {
- struct flowi fl = {
- .oif = 0,
- .nl_u = {
- .ip6_u = {
- .daddr = dest->addr.in6,
- .saddr = {
- .s6_addr32 =
- { 0, 0, 0, 0 },
- },
- },
- },
- };
+ u32 cookie;
- rt = (struct rt6_info *)ip6_route_output(&init_net,
- NULL, &fl);
- if (!rt) {
+ dst = __ip_vs_route_output_v6(net, &dest->addr.in6,
+ &dest->dst_saddr,
+ do_xfrm);
+ if (!dst) {
spin_unlock(&dest->dst_lock);
- IP_VS_DBG_RL("ip6_route_output error, dest:
%pI6\n",
- &dest->addr.in6);
return NULL;
}
- __ip_vs_dst_set(dest, 0, dst_clone(&rt->dst));
- IP_VS_DBG(10, "new dst %pI6, refcnt=%d\n",
- &dest->addr.in6,
+ rt = (struct rt6_info *) dst;
+ cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+ __ip_vs_dst_set(dest, 0, dst_clone(&rt->dst), cookie);
+ IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
+ &dest->addr.in6, &dest->dst_saddr,
atomic_read(&rt->dst.__refcnt));
}
+ if (ret_saddr)
+ ipv6_addr_copy(ret_saddr, &dest->dst_saddr);
spin_unlock(&dest->dst_lock);
} else {
- struct flowi fl = {
- .oif = 0,
- .nl_u = {
- .ip6_u = {
- .daddr = cp->daddr.in6,
- .saddr = {
- .s6_addr32 = { 0, 0, 0, 0 },
- },
- },
- },
- };
-
- rt = (struct rt6_info *)ip6_route_output(&init_net, NULL, &fl);
- if (!rt) {
- IP_VS_DBG_RL("ip6_route_output error, dest: %pI6\n",
- &cp->daddr.in6);
+ dst = __ip_vs_route_output_v6(net, &cp->daddr.in6, ret_saddr,
+ do_xfrm);
+ if (!dst)
return NULL;
- }
+ rt = (struct rt6_info *) dst;
}
return rt;
@@ -248,6 +268,7 @@ int
ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
struct ip_vs_protocol *pp)
{
+ struct net *net = dev_net(skb->dev);
struct rtable *rt; /* Route to the other host */
struct iphdr *iph = ip_hdr(skb);
u8 tos = iph->tos;
@@ -263,7 +284,7 @@ ip_vs_bypass_xmit(struct sk_buff *skb, s
EnterFunction(10);
- if (ip_route_output_key(&init_net, &rt, &fl)) {
+ if (ip_route_output_key(net, &rt, &fl)) {
IP_VS_DBG_RL("%s(): ip_route_output error, dest: %pI4\n",
__func__, &iph->daddr);
goto tx_error_icmp;
@@ -313,25 +334,18 @@ int
ip_vs_bypass_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
struct ip_vs_protocol *pp)
{
+ struct net *net = dev_net(skb->dev);
+ struct dst_entry *dst;
struct rt6_info *rt; /* Route to the other host */
struct ipv6hdr *iph = ipv6_hdr(skb);
int mtu;
- struct flowi fl = {
- .oif = 0,
- .nl_u = {
- .ip6_u = {
- .daddr = iph->daddr,
- .saddr = { .s6_addr32 = {0, 0, 0, 0} }, } },
- };
EnterFunction(10);
- rt = (struct rt6_info *)ip6_route_output(&init_net, NULL, &fl);
- if (!rt) {
- IP_VS_DBG_RL("%s(): ip6_route_output error, dest: %pI6\n",
- __func__, &iph->daddr);
+ dst = __ip_vs_route_output_v6(net, &iph->daddr, NULL, 0);
+ if (!dst)
goto tx_error_icmp;
- }
+ rt = (struct rt6_info *) dst;
/* MTU checking */
mtu = dst_mtu(&rt->dst);
@@ -397,7 +411,7 @@ ip_vs_nat_xmit(struct sk_buff *skb, stru
IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
}
- if (!(rt = __ip_vs_get_out_rt(cp, RT_TOS(iph->tos))))
+ if (!(rt = __ip_vs_get_out_rt(skb, cp, RT_TOS(iph->tos))))
goto tx_error_icmp;
/* MTU checking */
@@ -472,7 +486,7 @@ ip_vs_nat_xmit_v6(struct sk_buff *skb, s
IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
}
- rt = __ip_vs_get_out_rt_v6(cp);
+ rt = __ip_vs_get_out_rt_v6(skb, cp, NULL, 0);
if (!rt)
goto tx_error_icmp;
@@ -557,7 +571,6 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, s
struct iphdr *old_iph = ip_hdr(skb);
u8 tos = old_iph->tos;
__be16 df = old_iph->frag_off;
- sk_buff_data_t old_transport_header = skb->transport_header;
struct iphdr *iph; /* Our new IP header */
unsigned int max_headroom; /* The extra header space
needed */
int mtu;
@@ -572,7 +585,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, s
goto tx_error;
}
- if (!(rt = __ip_vs_get_out_rt(cp, RT_TOS(tos))))
+ if (!(rt = __ip_vs_get_out_rt(skb, cp, RT_TOS(tos))))
goto tx_error_icmp;
tdev = rt->dst.dev;
@@ -616,7 +629,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, s
old_iph = ip_hdr(skb);
}
- skb->transport_header = old_transport_header;
+ skb->transport_header = skb->network_header;
/* fix old IP header checksum */
ip_send_check(old_iph);
@@ -670,9 +683,9 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb
struct ip_vs_protocol *pp)
{
struct rt6_info *rt; /* Route to the other host */
+ struct in6_addr saddr; /* Source for tunnel */
struct net_device *tdev; /* Device to other host */
struct ipv6hdr *old_iph = ipv6_hdr(skb);
- sk_buff_data_t old_transport_header = skb->transport_header;
struct ipv6hdr *iph; /* Our new IP header */
unsigned int max_headroom; /* The extra header space needed */
int mtu;
@@ -687,17 +700,17 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb
goto tx_error;
}
- rt = __ip_vs_get_out_rt_v6(cp);
+ rt = __ip_vs_get_out_rt_v6(skb, cp, &saddr, 1);
if (!rt)
goto tx_error_icmp;
tdev = rt->dst.dev;
mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
- /* TODO IPv6: do we need this check in IPv6? */
- if (mtu < 1280) {
+ if (mtu < IPV6_MIN_MTU) {
dst_release(&rt->dst);
- IP_VS_DBG_RL("%s(): mtu less than 1280\n", __func__);
+ IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
+ IPV6_MIN_MTU);
goto tx_error;
}
if (skb_dst(skb))
@@ -730,7 +743,7 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb
old_iph = ipv6_hdr(skb);
}
- skb->transport_header = old_transport_header;
+ skb->transport_header = skb->network_header;
skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
@@ -750,8 +763,8 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb
be16_add_cpu(&iph->payload_len, sizeof(*old_iph));
iph->priority = old_iph->priority;
memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl));
- iph->daddr = rt->rt6i_dst.addr;
- iph->saddr = cp->vaddr.in6; /* rt->rt6i_src.addr; */
+ ipv6_addr_copy(&iph->daddr, &rt->rt6i_dst.addr);
+ ipv6_addr_copy(&iph->saddr, &saddr);
iph->hop_limit = old_iph->hop_limit;
/* Another hack: avoid icmp_send in ip_fragment */
@@ -791,7 +804,7 @@ ip_vs_dr_xmit(struct sk_buff *skb, struc
EnterFunction(10);
- if (!(rt = __ip_vs_get_out_rt(cp, RT_TOS(iph->tos))))
+ if (!(rt = __ip_vs_get_out_rt(skb, cp, RT_TOS(iph->tos))))
goto tx_error_icmp;
/* MTU checking */
@@ -843,7 +856,7 @@ ip_vs_dr_xmit_v6(struct sk_buff *skb, st
EnterFunction(10);
- rt = __ip_vs_get_out_rt_v6(cp);
+ rt = __ip_vs_get_out_rt_v6(skb, cp, NULL, 0);
if (!rt)
goto tx_error_icmp;
@@ -919,7 +932,7 @@ ip_vs_icmp_xmit(struct sk_buff *skb, str
* mangle and send the packet here (only for VS/NAT)
*/
- if (!(rt = __ip_vs_get_out_rt(cp, RT_TOS(ip_hdr(skb)->tos))))
+ if (!(rt = __ip_vs_get_out_rt(skb, cp, RT_TOS(ip_hdr(skb)->tos))))
goto tx_error_icmp;
/* MTU checking */
@@ -993,7 +1006,7 @@ ip_vs_icmp_xmit_v6(struct sk_buff *skb,
* mangle and send the packet here (only for VS/NAT)
*/
- rt = __ip_vs_get_out_rt_v6(cp);
+ rt = __ip_vs_get_out_rt_v6(skb, cp, NULL, 0);
if (!rt)
goto tx_error_icmp;
--
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