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net: vrf: Implement get_saddr for IPv6

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IPv6 source address selection needs to consider the real egress route.
Similar to IPv4 implement a get_saddr6 method which is called if
source address has not been set.  The get_saddr6 method does a full
lookup which means pulling a route from the VRF FIB table and properly
considering linklocal/multicast destination addresses. Lookup failures
(eg., unreachable) then cause the source address selection to fail
which gets propagated back to the caller.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2016-06-16 16:24:25 -07:00 committed by David S. Miller
parent a2e2ff560f
commit 0d240e7811
4 changed files with 86 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

41
drivers/net/vrf.c
View file

@ -999,6 +999,46 @@ static struct dst_entry *vrf_get_rt6_dst(const struct net_device *dev,
return dst;
}
/* called under rcu_read_lock */
static int vrf_get_saddr6(struct net_device *dev, const struct sock *sk,
struct flowi6 *fl6)
{
struct net *net = dev_net(dev);
struct dst_entry *dst;
struct rt6_info *rt;
int err;
if (rt6_need_strict(&fl6->daddr)) {
rt = vrf_ip6_route_lookup(net, dev, fl6, fl6->flowi6_oif,
RT6_LOOKUP_F_IFACE);
if (unlikely(!rt))
return 0;
dst = &rt->dst;
} else {
__u8 flags = fl6->flowi6_flags;
fl6->flowi6_flags |= FLOWI_FLAG_L3MDEV_SRC;
fl6->flowi6_flags |= FLOWI_FLAG_SKIP_NH_OIF;
dst = ip6_route_output(net, sk, fl6);
rt = (struct rt6_info *)dst;
fl6->flowi6_flags = flags;
}
err = dst->error;
if (!err) {
err = ip6_route_get_saddr(net, rt, &fl6->daddr,
sk ? inet6_sk(sk)->srcprefs : 0,
&fl6->saddr);
}
dst_release(dst);
return err;
}
#endif
static const struct l3mdev_ops vrf_l3mdev_ops = {
@ -1008,6 +1048,7 @@ static const struct l3mdev_ops vrf_l3mdev_ops = {
.l3mdev_l3_rcv = vrf_l3_rcv,
#if IS_ENABLED(CONFIG_IPV6)
.l3mdev_get_rt6_dst = vrf_get_rt6_dst,
.l3mdev_get_saddr6 = vrf_get_saddr6,
#endif
};

11
include/net/l3mdev.h
View file

@ -39,6 +39,9 @@ struct l3mdev_ops {
/* IPv6 ops */
struct dst_entry * (*l3mdev_get_rt6_dst)(const struct net_device *dev,
struct flowi6 *fl6);
int (*l3mdev_get_saddr6)(struct net_device *dev,
const struct sock *sk,
struct flowi6 *fl6);
};
#ifdef CONFIG_NET_L3_MASTER_DEV
@ -140,6 +143,8 @@ static inline bool netif_index_is_l3_master(struct net *net, int ifindex)
int l3mdev_get_saddr(struct net *net, int ifindex, struct flowi4 *fl4);
struct dst_entry *l3mdev_get_rt6_dst(struct net *net, struct flowi6 *fl6);
int l3mdev_get_saddr6(struct net *net, const struct sock *sk,
struct flowi6 *fl6);
static inline
struct sk_buff *l3mdev_l3_rcv(struct sk_buff *skb, u16 proto)
@ -230,6 +235,12 @@ struct dst_entry *l3mdev_get_rt6_dst(struct net *net, struct flowi6 *fl6)
return NULL;
}
static inline int l3mdev_get_saddr6(struct net *net, const struct sock *sk,
struct flowi6 *fl6)
{
return 0;
}
static inline
struct sk_buff *l3mdev_ip_rcv(struct sk_buff *skb)
{

12
net/ipv6/ip6_output.c
View file

@ -910,6 +910,13 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
int err;
int flags = 0;
if (ipv6_addr_any(&fl6->saddr) && fl6->flowi6_oif &&
(!*dst || !(*dst)->error)) {
err = l3mdev_get_saddr6(net, sk, fl6);
if (err)
goto out_err;
}
/* The correct way to handle this would be to do
* ip6_route_get_saddr, and then ip6_route_output; however,
* the route-specific preferred source forces the
@ -999,10 +1006,11 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
return 0;
out_err_release:
if (err == -ENETUNREACH)
IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
dst_release(*dst);
*dst = NULL;
out_err:
if (err == -ENETUNREACH)
IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
return err;
}

24
net/l3mdev/l3mdev.c
View file

@ -162,6 +162,30 @@ int l3mdev_get_saddr(struct net *net, int ifindex, struct flowi4 *fl4)
}
EXPORT_SYMBOL_GPL(l3mdev_get_saddr);
int l3mdev_get_saddr6(struct net *net, const struct sock *sk,
struct flowi6 *fl6)
{
struct net_device *dev;
int rc = 0;
if (fl6->flowi6_oif) {
rcu_read_lock();
dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
if (dev && netif_is_l3_slave(dev))
dev = netdev_master_upper_dev_get_rcu(dev);
if (dev && netif_is_l3_master(dev) &&
dev->l3mdev_ops->l3mdev_get_saddr6)
rc = dev->l3mdev_ops->l3mdev_get_saddr6(dev, sk, fl6);
rcu_read_unlock();
}
return rc;
}
EXPORT_SYMBOL_GPL(l3mdev_get_saddr6);
/**
* l3mdev_fib_rule_match - Determine if flowi references an
* L3 master device