* Remove &ifpp from ip6_output() in favor of ri->ri_nh_info
* Provide different wrappers to in6_selectsrc:
Currently it is used by 2 differenct type of customers:
- socket-based one, which all are unsure about provided
address scope and
- in-kernel ones (ND code mostly), which don't have
any sockets, options, crededentials, etc.
So, we provide two different wrappers to in6_selectsrc()
returning select source.
* Make different versions of selectroute():
Currenly selectroute() is used in two scenarios:
- SAS, via in6_selecsrc() -> in6_selectif() -> selectroute()
- output, via in6_output -> wrapper -> selectroute()
Provide different versions for each customer:
- fib6_lookup_nh_basic()-based in6_selectif() which is
capable of returning interface only, without MTU/NHOP/L2
calculations
- full-blown fib6_selectroute() with cached route/multipath/
MTU/L2
* Stop using routing table for link-local address lookups
* Add in6_ifawithifp_lla() to make for-us check faster for link-local
* Add in6_splitscope / in6_setllascope for faster embed/deembed scopes
* Use NHF_ namespace for all nhop flags
* Rename nhop_data -> nhop_prepend
* Rename fib4_lookup_nh_extended -> fib4_lookup_nh_ext
* Add "flags" argument to fib4_lookup_nh_ext() to specify whether we want
returned nh_ext structure to be refcounted or not.
structure without doinf L2 resolve. It also requires freeing
references by calling fib4_free_nh_ext().
Convert in_pcbladdr() to use it.
Convert tcp_maxmtu() to use it.
The goals of the new API is to provide consumers with minimal
needed information, but as fast as possible. So we provide
full nexthop info copied into alighed on-cache structure
instead of rte/ia pointers, their refcounts and locks.
This does not provide solution for protecting from egress
ifp destruction, but does not make it any worse.
Current changes:
nhops:
Add fib4_lookup_prepend() function which stores either full
L2+L3 prepend info (e.g. MAC header in case of plain IPv4) or
L3 info with NH_FLAGS_L2_INCOMPLETE flag indicating that no valid L2
info exists and we have to take "slow" path.
ip_output:
Currently ip[ 46]_output consumers use 'struct route' for
the following purposes:
1) double lookup avoidance(route caching)
2) plain route caching
3) get path MTU to be able to notify source.
The former pattern is mostly used by various tunnels
(gif, gre, stf). (Actually, gre is the only remaining,
others were already converted. Their locking model did
not scale good enogh to benefit from such caching, so
we have (temporarily) removed it without any performance
loss).
Plain route caching used by SCTP is simply wrong and should be removed.
Temporary break it for now just to be able to compile.
Optimize path mtu reporting by providing it in new 'route_info' stucture.
Minimize games with @ia locking/refcounting for route lookup:
add special nhop[46]_extended structure to store more route attributes.
Pointer to given structure can be passed to fib4_lookup_prepend() to indicate
we want this info (we actually needs it for UDP and raw IP).
ether_output:
Provide light-weight ether_output2() call to deal with
transmitting L2 frame (e.g. properly handle broadcast/simloop/bridge/
other L2 hooks before actually transmitting frame by if_transmit()).
Add a hack based on new RT_NHOP ro_flag to distinguish which version should
we call. Better way is probably to add a new "if_output_frame" driver
callbacks.
Next steps:
* Convert ip_fastfwd part
* Implement auto-growing array for per-radix nexthops
* Implement LLE tracking for nexthop calculations to be able to
immediately provide all necessary info in single route lookup
for gateway routes
* Switch radix locking scheme to runtime/cfg lock
* Implement multipath support for rtsock
* Implement "tracked nexthops" for tunnels (e.g. _proper_
nexthop caching)
* Add IPv6 support for remaining parts (postponed not to
interfere with user/ae/inet6 branch)
* Consider adding "if_output_frame" driver call to
ease logical frame pushing.
