ipv6: dad: don't remove dynamic addresses if link is down
Currently, when the link for $DEV is down, this command succeeds but the address is removed immediately by DAD (1): ip addr add 1111::12/64 dev $DEV valid_lft 3600 preferred_lft 1800 In the same situation, this will succeed and not remove the address (2): ip addr add 1111::12/64 dev $DEV ip addr change 1111::12/64 dev $DEV valid_lft 3600 preferred_lft 1800 The comment in addrconf_dad_begin() when !IF_READY makes it look like this is the intended behavior, but doesn't explain why: * If the device is not ready: * - keep it tentative if it is a permanent address. * - otherwise, kill it. We clearly cannot prevent userspace from doing (2), but we can make (1) work consistently with (2). addrconf_dad_stop() is only called in two cases: if DAD failed, or to skip DAD when the link is down. In that second case, the fix is to avoid deleting the address, like we already do for permanent addresses. Fixes: 3c21edbd ("[IPV6]: Defer IPv6 device initialization until the link becomes ready.") Signed-off-by:Sabrina Dubroca <sd@queasysnail.net> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
e1069bbf
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