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Message-ID: <4DA70C84.9050403@earthlink.net>
Date: Thu, 14 Apr 2011 11:02:28 -0400
From: Stephen Clark <sclark46@...thlink.net>
To: Daniel Walter <sahne@...0.at>
CC: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
davem@...emloft.net
Subject: Re: [PATCH 1/1] ipv6: RTA_PREFSRC support for ipv6 route source address
selection
On 04/14/2011 10:49 AM, Daniel Walter wrote:
> On Thu, Apr 14, 2011 at 10:01:09AM -0400, Stephen Clark wrote:
>
>> On 04/14/2011 03:10 AM, Daniel Walter wrote:
>>
>>> [ipv6] Add support for RTA_PREFSRC
>>>
>>> This patch allows a user to select the preferred source address
>>> for a specific IPv6-Route. It can be set via a netlink message
>>> setting RTA_PREFSRC to a valid IPv6 address which must be
>>> up on the device the route will be bound to.
>>>
>>>
>>> Signed-off-by: Daniel Walter<dwalter@...racuda.com>
>>> ---
>>> Repost patch, after fixing some warnings pointed out on netdev@
>>> applies clean against current linux-2.6 HEAD
>>>
>>> include/net/ip6_fib.h | 2 +
>>> include/net/ip6_route.h | 7 ++++
>>> net/ipv6/addrconf.c | 2 +
>>> net/ipv6/ip6_output.c | 8 ++--
>>> net/ipv6/route.c | 72 +++++++++++++++++++++++++++++++++++++++++++++--
>>> 5 files changed, 84 insertions(+), 7 deletions(-)
>>>
>>> ---
>>> diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
>>> index bc3cde0..98348d5 100644
>>> --- a/include/net/ip6_fib.h
>>> +++ b/include/net/ip6_fib.h
>>> @@ -42,6 +42,7 @@ struct fib6_config {
>>>
>>> struct in6_addr fc_dst;
>>> struct in6_addr fc_src;
>>> + struct in6_addr fc_prefsrc;
>>> struct in6_addr fc_gateway;
>>>
>>> unsigned long fc_expires;
>>> @@ -107,6 +108,7 @@ struct rt6_info {
>>> struct rt6key rt6i_dst ____cacheline_aligned_in_smp;
>>> u32 rt6i_flags;
>>> struct rt6key rt6i_src;
>>> + struct rt6key rt6i_prefsrc;
>>> u32 rt6i_metric;
>>> u32 rt6i_peer_genid;
>>>
>>> diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
>>> index c850e5f..86b1cb4 100644
>>> --- a/include/net/ip6_route.h
>>> +++ b/include/net/ip6_route.h
>>> @@ -84,6 +84,12 @@ extern int ip6_route_add(struct fib6_config *cfg);
>>> extern int ip6_ins_rt(struct rt6_info *);
>>> extern int ip6_del_rt(struct rt6_info *);
>>>
>>> +extern int ip6_route_get_saddr(struct net *net,
>>> + struct rt6_info *rt,
>>> + struct in6_addr *daddr,
>>> + unsigned int prefs,
>>> + struct in6_addr *saddr);
>>> +
>>> extern struct rt6_info *rt6_lookup(struct net *net,
>>> const struct in6_addr *daddr,
>>> const struct in6_addr *saddr,
>>> @@ -141,6 +147,7 @@ struct rt6_rtnl_dump_arg {
>>> extern int rt6_dump_route(struct rt6_info *rt, void *p_arg);
>>> extern void rt6_ifdown(struct net *net, struct net_device *dev);
>>> extern void rt6_mtu_change(struct net_device *dev, unsigned mtu);
>>> +extern void rt6_remove_prefsrc(struct inet6_ifaddr *ifp);
>>>
>>>
>>> /*
>>> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
>>> index 1493534..129d7e1 100644
>>> --- a/net/ipv6/addrconf.c
>>> +++ b/net/ipv6/addrconf.c
>>> @@ -825,6 +825,8 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
>>> dst_release(&rt->dst);
>>> }
>>>
>>> + /* clean up prefsrc entries */
>>> + rt6_remove_prefsrc(ifp);
>>> out:
>>> in6_ifa_put(ifp);
>>> }
>>> diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
>>> index 46cf7be..1f4c096 100644
>>> --- a/net/ipv6/ip6_output.c
>>> +++ b/net/ipv6/ip6_output.c
>>> @@ -930,10 +930,10 @@ static int ip6_dst_lookup_tail(struct sock *sk,
>>> goto out_err_release;
>>>
>>> if (ipv6_addr_any(&fl6->saddr)) {
>>> - err = ipv6_dev_get_saddr(net, ip6_dst_idev(*dst)->dev,
>>> - &fl6->daddr,
>>> - sk ? inet6_sk(sk)->srcprefs : 0,
>>> - &fl6->saddr);
>>> + struct rt6_info *rt = (struct rt6_info *) *dst;
>>> + err = ip6_route_get_saddr(net, rt,&fl6->daddr,
>>> + sk ? inet6_sk(sk)->srcprefs : 0,
>>> + &fl6->saddr);
>>> if (err)
>>> goto out_err_release;
>>> }
>>> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
>>> index 843406f..af26cc10 100644
>>> --- a/net/ipv6/route.c
>>> +++ b/net/ipv6/route.c
>>> @@ -1325,6 +1325,16 @@ int ip6_route_add(struct fib6_config *cfg)
>>> if (dev == NULL)
>>> goto out;
>>>
>>> + if (!ipv6_addr_any(&cfg->fc_prefsrc)) {
>>> + if (!ipv6_chk_addr(net,&cfg->fc_prefsrc, dev, 0)) {
>>> + err = -EINVAL;
>>> + goto out;
>>> + }
>>> + ipv6_addr_copy(&rt->rt6i_prefsrc.addr,&cfg->fc_prefsrc);
>>> + rt->rt6i_prefsrc.plen = 128;
>>> + } else
>>> + rt->rt6i_prefsrc.plen = 0;
>>> +
>>> if (cfg->fc_flags& (RTF_GATEWAY | RTF_NONEXTHOP)) {
>>> rt->rt6i_nexthop = __neigh_lookup_errno(&nd_tbl,&rt->rt6i_gateway, dev);
>>> if (IS_ERR(rt->rt6i_nexthop)) {
>>> @@ -2037,6 +2047,55 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
>>> return rt;
>>> }
>>>
>>> +int ip6_route_get_saddr(struct net *net,
>>> + struct rt6_info *rt,
>>> + struct in6_addr *daddr,
>>> + unsigned int prefs,
>>> + struct in6_addr *saddr)
>>> +{
>>> + struct inet6_dev *idev = ip6_dst_idev((struct dst_entry*)rt);
>>> + int err = 0;
>>> + if (rt->rt6i_prefsrc.plen)
>>> + ipv6_addr_copy(saddr,&rt->rt6i_prefsrc.addr);
>>> + else
>>> + err = ipv6_dev_get_saddr(net, idev ? idev->dev : NULL,
>>> + daddr, prefs, saddr);
>>> + return err;
>>> +}
>>> +
>>> +/* remove deleted ip from prefsrc entries */
>>> +struct arg_dev_net_ip {
>>> + struct net_device *dev;
>>> + struct net *net;
>>> + struct in6_addr *addr;
>>> +};
>>> +
>>> +static int fib6_remove_prefsrc(struct rt6_info *rt, void *arg)
>>> +{
>>> + struct net_device *dev = ((struct arg_dev_net_ip *)arg)->dev;
>>> + struct net *net = ((struct arg_dev_net_ip *)arg)->net;
>>> + struct in6_addr *addr = ((struct arg_dev_net_ip *)arg)->addr;
>>> +
>>> + if (((void *)rt->rt6i_dev == dev || dev == NULL)&&
>>> + rt != net->ipv6.ip6_null_entry&&
>>> + ipv6_addr_equal(addr,&rt->rt6i_prefsrc.addr)) {
>>> + /* remove prefsrc entry */
>>> + rt->rt6i_prefsrc.plen = 0;
>>> + }
>>> + return 0;
>>> +}
>>> +
>>> +void rt6_remove_prefsrc(struct inet6_ifaddr *ifp)
>>> +{
>>> + struct net *net = dev_net(ifp->idev->dev);
>>> + struct arg_dev_net_ip adni = {
>>> + .dev = ifp->idev->dev,
>>> + .net = net,
>>> + .addr =&ifp->addr,
>>> + };
>>> + fib6_clean_all(net, fib6_remove_prefsrc, 0,&adni);
>>> +}
>>> +
>>> struct arg_dev_net {
>>> struct net_device *dev;
>>> struct net *net;
>>> @@ -2183,6 +2242,9 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
>>> nla_memcpy(&cfg->fc_src, tb[RTA_SRC], plen);
>>> }
>>>
>>> + if (tb[RTA_PREFSRC])
>>> + nla_memcpy(&cfg->fc_prefsrc, tb[RTA_PREFSRC], 16);
>>> +
>>> if (tb[RTA_OIF])
>>> cfg->fc_ifindex = nla_get_u32(tb[RTA_OIF]);
>>>
>>> @@ -2325,13 +2387,17 @@ static int rt6_fill_node(struct net *net,
>>> #endif
>>> NLA_PUT_U32(skb, RTA_IIF, iif);
>>> } else if (dst) {
>>> - struct inet6_dev *idev = ip6_dst_idev(&rt->dst);
>>> struct in6_addr saddr_buf;
>>> - if (ipv6_dev_get_saddr(net, idev ? idev->dev : NULL,
>>> - dst, 0,&saddr_buf) == 0)
>>> + if (ip6_route_get_saddr(net, rt, dst, 0,&saddr_buf) == 0)
>>> NLA_PUT(skb, RTA_PREFSRC, 16,&saddr_buf);
>>> }
>>>
>>> + if (rt->rt6i_prefsrc.plen) {
>>> + struct in6_addr saddr_buf;
>>> + ipv6_addr_copy(&saddr_buf,&rt->rt6i_prefsrc.addr);
>>> + NLA_PUT(skb, RTA_PREFSRC, 16,&saddr_buf);
>>> + }
>>> +
>>> if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst))< 0)
>>> goto nla_put_failure;
>>>
>> What userspace application will be used to set this?
>>
> iproute2 already has support for this, since it is using
> RTA_PREFSRC for ipv4.
>
> ip -6 r a 2001:db8:a::/64 via 2001:db8:b::1 src 2001:db8:b::2
>
>
Fantastic!
--
"They that give up essential liberty to obtain temporary safety,
deserve neither liberty nor safety." (Ben Franklin)
"The course of history shows that as a government grows, liberty
decreases." (Thomas Jefferson)
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