ipv6: Fix default route failover when CONFIG_IPV6_ROUTER_PREF=n
I believe this commit from 2008 was incorrect: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=398bcbeb When CONFIG_IPV6_ROUTER_PREF is disabled, the kernel should follow RFC4861 section 6.3.6: if no route is NUD_VALID, then traffic should be sprayed across all routers (indirectly triggering NUD) until one of them becomes NUD_VALID. However, the following experiment demonstrates that this does not work: 1) Connect to an IPv6 network. 2) Change the router's MAC (and link-local) address. The kernel will lock onto the first router and never try the new one, even if the first becomes unreachable. This patch fixes the problem by allowing rt6_check_neigh() to return 0; if all routers return 0, then rt6_select() will fall back to round-robin behavior. This patch should have no effect when CONFIG_IPV6_ROUTER_PREF=y. Note that rt6_check_neigh() is only used in a boolean context, so I've changed its return type accordingly. Signed-off-by:Paul Marks <pmarks@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
5d097109
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