Hello
I think this patch should be stopped since it doesn't work in some
cases.
There is also a bug in the patch.
ip6_route_output() returns a key as dest address
which can be a network and that's not a good dest address.
(It can be seen if the tunnel remote endpoint has to pass through an
router/gateway)
@@ -750,8 +763,8 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb
...
...
- ipv6_addr_copy(&iph->daddr, &rt->rt6i_dst.addr);
+ ipv6_addr_copy(&iph->daddr, &cp->dest->addr.in6);
The principle for it is wrong, it's more or less impossible to get the
expected address from ipv6_get_saddr_eval(), depending on your network
topology.
Since there must be an address set on the remote/local pair for a IPv6
tunnel and you can't predict what source address you will get the
function is more or less useless.
After spending a day single stepping through the IPv6 stack I'm more or
less sure that:
- The only way to get IPv6 tunnels to work in a predictable way is to
add a "tunnel source address" to the ipvsadm commad.
What to do ?
- add a --tunsrc switch to ipvsadm -i command ?
or
- Disable the IPv6 tunnel mode ?
or
- Leave it as is ?
Regards
Hans Schillstrom <hans.schillstrom@xxxxxxxxxxxx>
On Sun, 2010-09-26 at 16:21 +0200, Julian Anastasov wrote:
> Hello,
>
> On Sun, 26 Sep 2010, Simon Horman wrote:
>
> > From: Julian Anastasov <ja@xxxxxx>
> >
> > 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.
> >
> > 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.
> >
> > 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 ip6_route_output() to look up the route cache and
> > then use ipv6_dev_get_saddr(...) to set the source address of the
> > encapsulated packet.
> >
> > Additionally, cache the results in new destination
> > fields: dst_cookie and dst_saddr and properly check the
> > returned dst from ip6_route_output. We now add xfrm_lookup
> > call only for the tunneling method where the source address
> > is a local one.
> >
> > Original patch by Hans Schillstrom.
> > Check dst state and cache results for IPv6 by Julian Anastasov.
> >
> > Tested-by: Hans Schillstrom <hans.schillstrom@xxxxxxxxxxxx>
> > Signed-off-by: Julian Anastasov <ja@xxxxxx>
> > Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
> >
> > ---
> >
> > * v1
> >
> > This is Julian's patch with a slightly edited version of the description
> > from Hans's original patch.
> >
> > * v2
> >
> > Updated changelog as per commends from Julian
> >
> > Is everyone ok with pushing this?
> >
> > 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;
> >
>
> Looks good to me
>
> Regards
>
> --
> Julian Anastasov <ja@xxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe lvs-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
