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Julian Anastasov authored
Allow some non-cached routes to use non-expired fnhe: 1. ip_del_fnhe: moved above and now called by find_exception. The 4.5+ commit deed49df expires fnhe only when caching routes. Change that to: 1.1. use fnhe for non-cached local output routes, with the help from (2) 1.2. allow __mkroute_input to detect expired fnhe (outdated fnhe_gw, for example) when do_cache is false, eg. when itag!=0 for unicast destinations. 2. __mkroute_output: keep fi to allow local routes with orig_oif != 0 to use fnhe info even when the new route will not be cached into fnhe. After commit 839da4d9 ("net: ipv4: set orig_oif based on fib result for local traffic") it means all local routes will be affected because they are not cached. This change is used to solve a PMTU problem with IPVS (and probably Netfilter DNAT) setups that redirect local clients from target local IP (local route to Virtual IP) to new remote IP target, eg. IPVS TUN real server. Loopback has 64K MTU and we need to create fnhe on the local route that will keep the reduced PMTU for the Virtual IP. Without this change fnhe_pmtu is updated from ICMP but never exposed to non-cached local routes. This includes routes with flowi4_oif!=0 for 4.6+ and with flowi4_oif=any for 4.14+). 3. update_or_create_fnhe: make sure fnhe_expires is not 0 for new entries Fixes: 839da4d9 ("net: ipv4: set orig_oif based on fib result for local traffic") Fixes: d6d5e999 ("route: do not cache fib route info on local routes with oif") Fixes: deed49df ("route: check and remove route cache when we get route") Cc: David Ahern <dsahern@gmail.com> Cc: Xin Long <lucien.xin@gmail.com> Signed-off-by:
Julian Anastasov <ja@ssi.bg> Acked-by:
David Ahern <dsahern@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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