Wait for link-local address for DHCPv6

dhclient -6 fails if the interface to be configures has no link-local address.
This is especially problematic when only DHCPv6 is used
(e.g., --ip=none --ip6=dhcp), because the wait for a DHCPv4 lease is usually
ample time for the LL address to become available on the IPv6 link.
The LL address must not be tenative.

Therefore, this patch implements waiting for a non-tentative link-local
address in fnet for DHCPv6 configured interfaces.

The command fnet waitll <if> waits for an LL address on the interface <if>.

Currently, the maximum waiting time is 30 seconds,
and the kernel is polled through rtnetlink every 500 milliseconds.
These values seem sufficient for virtual bridged networks,
e.g., libvirt NAT networks.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/fnet/fnet.h b/src/fnet/fnet.h
index 4900967f7..4d0d62b39 100644
--- a/src/fnet/fnet.h
+++ b/src/fnet/fnet.h
@@ -47,6 +47,7 @@ int net_get_mac(const char *ifname, unsigned char mac[6]);
 void net_if_ip(const char *ifname, uint32_t ip, uint32_t mask, int mtu);
 int net_if_mac(const char *ifname, const unsigned char mac[6]);
 void net_if_ip6(const char *ifname, const char *addr6);
+void net_if_waitll(const char *ifname);
 
 
 // arp.c