Question about locking in ndisc.c

I've been reading through net/ipv6/ndisc.c recently (trying to
determine if it'd be feasible to implement RFC6724 Rule 5.5), and I'm
confused by the lack of visible locking in the
ndisc_router_discovery() function.

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=net/ipv6/ndisc.c;h=2edce30ef7338cdf1916eef98b353c7dbbc7bcda;hb=HEAD#l1048

There are values written all over the place, for example:
- in6_dev->if_flags
- neigh->flags
- rt->rt6i_flags
- in6_dev->nd_parms->...
- in6_dev->tstamp

But I've looked through ndisc.c and icmp.c, and I can't find anything
that would protect this data from concurrent access.  Is there
something I'm missing?