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ipv6: add support of peer address
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This patch adds the support of peer address for IPv6. For example, it is
possible to specify the remote end of a 6inY tunnel.
This was already possible in IPv4:
 ip addr add ip1 peer ip2 dev dev1

The peer address is specified with IFA_ADDRESS and the local address with
IFA_LOCAL (like explained in include/uapi/linux/if_addr.h).
Note that the API is not changed, because before this patch, it was not
possible to specify two different addresses in IFA_LOCAL and IFA_REMOTE.
There is a small change for the dump: if the peer is different from ::,
IFA_ADDRESS will contain the peer address instead of the local address.

Signed-off-by: Nicolas Dichtel <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@NicolasDichtel @davem330
NicolasDichtel authored and davem330 committed May 19, 2013
1 parent 5199dfe commit caeaba7
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Showing 2 changed files with 48 additions and 17 deletions.
1 change: 1 addition & 0 deletions include/net/if_inet6.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,7 @@ struct inet6_ifaddr {
bool tokenized;

struct rcu_head rcu;
struct in6_addr peer_addr;
};

struct ip6_sf_socklist {
Expand Down
64 changes: 47 additions & 17 deletions net/ipv6/addrconf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2402,6 +2402,7 @@ int addrconf_set_dstaddr(struct net *net, void __user *arg)
* Manual configuration of address on an interface
*/
static int inet6_addr_add(struct net *net, int ifindex, const struct in6_addr *pfx,
const struct in6_addr *peer_pfx,
unsigned int plen, __u8 ifa_flags, __u32 prefered_lft,
__u32 valid_lft)
{
Expand Down Expand Up @@ -2457,6 +2458,8 @@ static int inet6_addr_add(struct net *net, int ifindex, const struct in6_addr *p
ifp->valid_lft = valid_lft;
ifp->prefered_lft = prefered_lft;
ifp->tstamp = jiffies;
if (peer_pfx)
ifp->peer_addr = *peer_pfx;
spin_unlock_bh(&ifp->lock);

addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev,
Expand Down Expand Up @@ -2526,7 +2529,7 @@ int addrconf_add_ifaddr(struct net *net, void __user *arg)
return -EFAULT;

rtnl_lock();
err = inet6_addr_add(net, ireq.ifr6_ifindex, &ireq.ifr6_addr,
err = inet6_addr_add(net, ireq.ifr6_ifindex, &ireq.ifr6_addr, NULL,
ireq.ifr6_prefixlen, IFA_F_PERMANENT,
INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
rtnl_unlock();
Expand Down Expand Up @@ -3610,18 +3613,20 @@ static void addrconf_verify(unsigned long foo)
rcu_read_unlock_bh();
}

static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local)
static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local,
struct in6_addr **peer_pfx)
{
struct in6_addr *pfx = NULL;

*peer_pfx = NULL;

if (addr)
pfx = nla_data(addr);

if (local) {
if (pfx && nla_memcmp(local, pfx, sizeof(*pfx)))
pfx = NULL;
else
pfx = nla_data(local);
*peer_pfx = pfx;
pfx = nla_data(local);
}

return pfx;
Expand All @@ -3639,15 +3644,15 @@ inet6_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh)
struct net *net = sock_net(skb->sk);
struct ifaddrmsg *ifm;
struct nlattr *tb[IFA_MAX+1];
struct in6_addr *pfx;
struct in6_addr *pfx, *peer_pfx;
int err;

err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv6_policy);
if (err < 0)
return err;

ifm = nlmsg_data(nlh);
pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL]);
pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer_pfx);
if (pfx == NULL)
return -EINVAL;

Expand Down Expand Up @@ -3705,7 +3710,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
struct net *net = sock_net(skb->sk);
struct ifaddrmsg *ifm;
struct nlattr *tb[IFA_MAX+1];
struct in6_addr *pfx;
struct in6_addr *pfx, *peer_pfx;
struct inet6_ifaddr *ifa;
struct net_device *dev;
u32 valid_lft = INFINITY_LIFE_TIME, preferred_lft = INFINITY_LIFE_TIME;
Expand All @@ -3717,7 +3722,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
return err;

ifm = nlmsg_data(nlh);
pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL]);
pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer_pfx);
if (pfx == NULL)
return -EINVAL;

Expand Down Expand Up @@ -3745,7 +3750,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
* It would be best to check for !NLM_F_CREATE here but
* userspace alreay relies on not having to provide this.
*/
return inet6_addr_add(net, ifm->ifa_index, pfx,
return inet6_addr_add(net, ifm->ifa_index, pfx, peer_pfx,
ifm->ifa_prefixlen, ifa_flags,
preferred_lft, valid_lft);
}
Expand Down Expand Up @@ -3802,6 +3807,7 @@ static inline int rt_scope(int ifa_scope)
static inline int inet6_ifaddr_msgsize(void)
{
return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
+ nla_total_size(16) /* IFA_LOCAL */
+ nla_total_size(16) /* IFA_ADDRESS */
+ nla_total_size(sizeof(struct ifa_cacheinfo));
}
Expand Down Expand Up @@ -3840,13 +3846,22 @@ static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa,
valid = INFINITY_LIFE_TIME;
}

if (nla_put(skb, IFA_ADDRESS, 16, &ifa->addr) < 0 ||
put_cacheinfo(skb, ifa->cstamp, ifa->tstamp, preferred, valid) < 0) {
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
if (ipv6_addr_type(&ifa->peer_addr) != IPV6_ADDR_ANY) {
if (nla_put(skb, IFA_LOCAL, 16, &ifa->addr) < 0 ||
nla_put(skb, IFA_ADDRESS, 16, &ifa->peer_addr) < 0)
goto error;
} else
if (nla_put(skb, IFA_ADDRESS, 16, &ifa->addr) < 0)
goto error;

if (put_cacheinfo(skb, ifa->cstamp, ifa->tstamp, preferred, valid) < 0)
goto error;

return nlmsg_end(skb, nlh);

error:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}

static int inet6_fill_ifmcaddr(struct sk_buff *skb, struct ifmcaddr6 *ifmca,
Expand Down Expand Up @@ -4046,7 +4061,7 @@ static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr *nlh)
struct net *net = sock_net(in_skb->sk);
struct ifaddrmsg *ifm;
struct nlattr *tb[IFA_MAX+1];
struct in6_addr *addr = NULL;
struct in6_addr *addr = NULL, *peer;
struct net_device *dev = NULL;
struct inet6_ifaddr *ifa;
struct sk_buff *skb;
Expand All @@ -4056,7 +4071,7 @@ static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr *nlh)
if (err < 0)
goto errout;

addr = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL]);
addr = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer);
if (addr == NULL) {
err = -EINVAL;
goto errout;
Expand Down Expand Up @@ -4564,11 +4579,26 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
ip6_ins_rt(ifp->rt);
if (ifp->idev->cnf.forwarding)
addrconf_join_anycast(ifp);
if (ipv6_addr_type(&ifp->peer_addr) != IPV6_ADDR_ANY)
addrconf_prefix_route(&ifp->peer_addr, 128,
ifp->idev->dev, 0, 0);
break;
case RTM_DELADDR:
if (ifp->idev->cnf.forwarding)
addrconf_leave_anycast(ifp);
addrconf_leave_solict(ifp->idev, &ifp->addr);
if (ipv6_addr_type(&ifp->peer_addr) != IPV6_ADDR_ANY) {
struct rt6_info *rt;
struct net_device *dev = ifp->idev->dev;

rt = rt6_lookup(dev_net(dev), &ifp->peer_addr, NULL,
dev->ifindex, 1);
if (rt) {
dst_hold(&rt->dst);
if (ip6_del_rt(rt))
dst_free(&rt->dst);
}
}
dst_hold(&ifp->rt->dst);

if (ip6_del_rt(ifp->rt))
Expand Down

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