freebsd-dev/etc/mtree
Alexander V. Chernikov a666325282 Introduce nexthop objects and new routing KPI.
This is the foundational change for the routing subsytem rearchitecture.
 More details and goals are available in https://reviews.freebsd.org/D24141 .

This patch introduces concept of nexthop objects and new nexthop-based
 routing KPI.

Nexthops are objects, containing all necessary information for performing
 the packet output decision. Output interface, mtu, flags, gw address goes
 there. For most of the cases, these objects will serve the same role as
 the struct rtentry is currently serving.
Typically there will be low tens of such objects for the router even with
 multiple BGP full-views, as these objects will be shared between routing
 entries. This allows to store more information in the nexthop.

New KPI:

struct nhop_object *fib4_lookup(uint32_t fibnum, struct in_addr dst,
  uint32_t scopeid, uint32_t flags, uint32_t flowid);
struct nhop_object *fib6_lookup(uint32_t fibnum, const struct in6_addr *dst6,
  uint32_t scopeid, uint32_t flags, uint32_t flowid);

These 2 function are intended to replace all all flavours of
 <in_|in6_>rtalloc[1]<_ign><_fib>, mpath functions  and the previous
 fib[46]-generation functions.

Upon successful lookup, they return nexthop object which is guaranteed to
 exist within current NET_EPOCH. If longer lifetime is desired, one can
 specify NHR_REF as a flag and get a referenced version of the nexthop.
 Reference semantic closely resembles rtentry one, allowing sed-style conversion.

Additionally, another 2 functions are introduced to support uRPF functionality
 inside variety of our firewalls. Their primary goal is to hide the multipath
 implementation details inside the routing subsystem, greatly simplifying
 firewalls implementation:

int fib4_lookup_urpf(uint32_t fibnum, struct in_addr dst, uint32_t scopeid,
  uint32_t flags, const struct ifnet *src_if);
int fib6_lookup_urpf(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid,
  uint32_t flags, const struct ifnet *src_if);

All functions have a separate scopeid argument, paving way to eliminating IPv6 scope
 embedding and allowing to support IPv4 link-locals in the future.

Structure changes:
 * rtentry gets new 'rt_nhop' pointer, slightly growing the overall size.
 * rib_head gets new 'rnh_preadd' callback pointer, slightly growing overall sz.

Old KPI:
During the transition state old and new KPI will coexists. As there are another 4-5
 decent-sized conversion patches, it will probably take a couple of weeks.
To support both KPIs, fields not required by the new KPI (most of rtentry) has to be
 kept, resulting in the temporary size increase.
Once conversion is finished, rtentry will notably shrink.

More details:
* architectural overview: https://reviews.freebsd.org/D24141
* list of the next changes: https://reviews.freebsd.org/D24232

Reviewed by:	ae,glebius(initial version)
Differential Revision:	https://reviews.freebsd.org/D24232
2020-04-12 14:30:00 +00:00
..
BSD.debug.dist * Bump version numbers to 10.0.0 2020-01-25 16:23:49 +00:00
BSD.include.dist Introduce nexthop objects and new routing KPI. 2020-04-12 14:30:00 +00:00
BSD.lib32.dist Normalize the g(eom,cache,part,...) build. 2018-06-25 19:55:15 +00:00
BSD.libsoft.dist Add libsoft to the tree, just like lib32. 2016-01-03 04:32:05 +00:00
BSD.release.dist
BSD.root.dist Import the kyua test framework. 2020-03-23 19:01:23 +00:00
BSD.sendmail.dist BSD.sendmail.dist: simplify mqueue group name setting 2020-03-22 16:55:20 +00:00
BSD.tests.dist Add a basic test for nvmecontrol 2020-04-07 20:26:42 +00:00
BSD.usr.dist Always install backward compatibility timezones, as they are installed 2020-04-09 05:11:18 +00:00
BSD.var.dist pkgbase: create sendmail directories only from BSD.sendmail.dist 2020-03-22 15:37:38 +00:00
Makefile Unconditionally install etc/mtree/BSD.debug.dist again 2017-07-25 00:28:23 +00:00
README

$FreeBSD$

Note: If you modify these files, please keep hier(7) updated!

These files are used to create empty file hierarchies for building the
system into.  Some notes about working with them are placed here to try
and keep them in good working order.

    a)  The files use 4 space indentation, and other than in the header
        comments, should not contain any tabs.  An indentation of 4 is
        preferable to the standard indentation of 8 because the indentation
        of levels in these files can become quite deep causing the line to
        overflow 80 characters.

        This also matches with the files generated when using the
        mtree -c option, which was implemented that way for the same reason.

    b)  Only directories should be listed here.

    c)  The listing should be kept in filename sorted order.

    d)  Sanity checking changes to these files can be done by following
        this procedure (the sed -e is ugly, but fixing mtree -c to
        not emit the trailing white space would be even uglier):

            mkdir /tmp/MTREE
            mtree -deU -f BSD.X.dist -p /tmp/MTREE
            mtree -cdin -k uname,gname,mode -p /tmp/MTREE | \
		sed -e 's/ *$//' >BSD.X.new
            diff -u BSD.X.dist BSD.X.new
            rm -r /tmp/MTREE

        Note that you will get some differences about /set lines,
        and uname= gname= on certain directory areas, mainly man page
        sections.  This is caused by mtree not having a look ahead
        mechanism for making better selections for these as it
        traverses the hierarchy.

        The BSD.X.new file should NOT be committed, as it will be missing
        the correct header, and important keywords like ``nochange''.
        Simply use the diff for a sanity check to make sure things are in
        the correct order and correctly indented.

    e)  Further sanity checking of the system builds with DESTDIR=/someplace
        are more complicated, but can often catch missing entries in these
        files.  I tend to run this more complete sanity check shortly after
        the target date for a new release is announced.

        If you want details on it bug me about it via email to
        rgrimes@FreeBSD.org.