messages before accessing message fields that may not be present,
removing dead/duplicate/misleading code along the way.
Document the message format for each routing socket message in
route.h.
Fix a bug in usr.bin/netstat introduced in r287351 that resulted in
pointer computation with essentially random 16-bit offsets and
dereferencing of the results.
Reviewed by: ae
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D10330
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
The "rtentry" zone does not use UMA_ZONE_ZINIT, so it is invalid to assume the
mutex's memory will be zero. Without MTX_NEW, garbage backing memory may
trigger the "re-initializing a mutex" assertion.
PR: 200991
Submitted by: Chang-Hsien Tsai <luke.tw AT gmail.com>
family as an argument as well.
This will be used to cleanup individual protocols during VNET teardown.
Obtained from: projects/vnet
Sponsored by: The FreeBSD Foundation
but removed due to other changes in the system. Restore the llentry pointer
to the "struct route", and use it to cache the L2 lookup (ARP or ND6) as
appropriate.
Submitted by: Mike Karels
Differential Revision: https://reviews.freebsd.org/D6262
- properly V_irtualise variable access unbreaking VIMAGE kernels.
- remove the volatile from the function return type to make architecture
using gcc happy [-Wreturn-type]
"type qualifiers ignored on function return type"
I am not entirely happy with this solution putting the u_int there
but it will do for now.
route caching for TCP, with some improvements. In particular, invalidate
the route cache if a new route is added, which might be a better match.
The cache is automatically invalidated if the old route is deleted.
Submitted by: Mike Karels
Reviewed by: gnn
Differential Revision: https://reviews.freebsd.org/D4306
There are number of radix consumers in kernel land (pf,ipfw,nfs,route)
with different requirements. In fact, first 3 don't have _any_ requirements
and first 2 does not use radix locking. On the other hand, routing
structure do have these requirements (rnh_gen, multipath, custom
to-be-added control plane functions, different locking).
Additionally, radix should not known anything about its consumers internals.
So, radix code now uses tiny 'struct radix_head' structure along with
internal 'struct radix_mask_head' instead of 'struct radix_node_head'.
Existing consumers still uses the same 'struct radix_node_head' with
slight modifications: they need to pass pointer to (embedded)
'struct radix_head' to all radix callbacks.
Routing code now uses new 'struct rib_head' with different locking macro:
RADIX_NODE_HEAD prefix was renamed to RIB_ (which stands for routing
information base).
New net/route_var.h header was added to hold routing subsystem internal
data. 'struct rib_head' was placed there. 'struct rtentry' will also
be moved there soon.
The only piece of information that is required is rt_flags subset.
In particular, if_loop() requires RTF_REJECT and RTF_BLACKHOLE flags
to check if this particular mbuf needs to be dropped (and what
error should be returned).
Note that if_loop() will always return EHOSTUNREACH for "reject" routes
regardless of RTF_HOST flag existence. This is due to upcoming routing
changes where RTF_HOST value won't be available as lookup result.
All other functions require RTF_GATEWAY flag to check if they need
to return EHOSTUNREACH instead of EHOSTDOWN error.
There are 11 places where non-zero 'struct route' is passed to if_output().
For most of the callers (forwarding, bpf, arp) does not care about exact
error value. In fact, the only place where this result is propagated
is ip_output(). (ip6_output() passes NULL route to nd6_output_ifp()).
Given that, add 3 new 'struct route' flags (RT_REJECT, RT_BLACKHOLE and
RT_IS_GW) and inline function (rt_update_ro_flags()) to copy necessary
rte flags to ro_flags. Call this function in ip_output() after looking up/
verifying rte.
Reviewed by: ae
Such handler should pass different set of variables, instead
of directly providing 2 locked route entries.
Given that it hasn't been really used since at least 2012, remove
current code.
Will re-add it after finishing most major routing-related changes.
Discussed with: np
entries data in unified format.
There are control plane functions that require information other than
just next-hop data (e.g. individual rtentry fields like flags or
prefix/mask). Given that the goal is to avoid rte reference/refcounting,
re-use rt_addrinfo structure to store most rte fields. If caller wants
to retrieve key/mask or gateway (which are sockaddrs and are allocated
separately), it needs to provide sufficient-sized sockaddrs structures
w/ ther pointers saved in passed rt_addrinfo.
Convert:
* lltable new records checks (in_lltable_rtcheck(),
nd6_is_new_addr_neighbor().
* rtsock pre-add/change route check.
* IPv6 NS ND-proxy check (RADIX_MPATH code was eliminated because
1) we don't support RTF_ANNOUNCE ND-proxy for networks and there should
not be multiple host routes for such hosts 2) if we have multiple
routes we should inspect them (which is not done). 3) the entire idea
of abusing KRT as storage for ND proxy seems odd. Userland programs
should be used for that purpose).
Add ro_mtu field to 'struct route' to be able to pass lookup MTU back to
the caller.
Currently, ip6_getpmtu() has 2 totally different use cases:
1) control plane (IPV6_PATHMTU req), where we just need to calculate MTU
and return it, w/o any reusability.
2) Actual ip6_output() data path where we (nearly) always use the provided
route lookup data. If this data is not 'valid' we need to perform another
lookup and save the result (which cannot be re-used by ip6_output()).
Given that, handle 1) by calling separate function doing rte lookup itself.
Resulting MTU is calculated by (newly-added) ip6_calcmtu() used by both
ip6_getpmtu_ctl() and ip6_getpmtu().
For 2) instead of storing ref'ed rte, store mtu (the only needed data
from the lookup result) inside newly-added ro_mtu field.
'struct route' was shrinked by 8(or 4 bytes) in r292978. Grow it again
by 4 bytes. New ro_mtu field will be used in other places like
ip/tcp_output (EMSGSIZE handling from output routines).
Reviewed by: ae
Add if_requestencap() interface method which is capable of calculating
various link headers for given interface. Right now there is support
for INET/INET6/ARP llheader calculation (IFENCAP_LL type request).
Other types are planned to support more complex calculation
(L2 multipath lagg nexthops, tunnel encap nexthops, etc..).
Reshape 'struct route' to be able to pass additional data (with is length)
to prepend to mbuf.
These two changes permits routing code to pass pre-calculated nexthop data
(like L2 header for route w/gateway) down to the stack eliminating the
need for other lookups. It also brings us closer to more complex scenarios
like transparently handling MPLS nexthops and tunnel interfaces.
Last, but not least, it removes layering violation introduced by flowtable
code (ro_lle) and simplifies handling of existing if_output consumers.
ARP/ND changes:
Make arp/ndp stack pre-calculate link header upon installing/updating lle
record. Interface link address change are handled by re-calculating
headers for all lles based on if_lladdr event. After these changes,
arpresolve()/nd6_resolve() returns full pre-calculated header for
supported interfaces thus simplifying if_output().
Move these lookups to separate ether_resolve_addr() function which ether
returs error or fully-prepared link header. Add <arp|nd6_>resolve_addr()
compat versions to return link addresses instead of pre-calculated data.
BPF changes:
Raw bpf writes occupied _two_ cases: AF_UNSPEC and pseudo_AF_HDRCMPLT.
Despite the naming, both of there have ther header "complete". The only
difference is that interface source mac has to be filled by OS for
AF_UNSPEC (controlled via BIOCGHDRCMPLT). This logic has to stay inside
BPF and not pollute if_output() routines. Convert BPF to pass prepend data
via new 'struct route' mechanism. Note that it does not change
non-optimized if_output(): ro_prepend handling is purely optional.
Side note: hackish pseudo_AF_HDRCMPLT is supported for ethernet and FDDI.
It is not needed for ethernet anymore. The only remaining FDDI user is
dev/pdq mostly untouched since 2007. FDDI support was eliminated from
OpenBSD in 2013 (sys/net/if_fddisubr.c rev 1.65).
Flowtable changes:
Flowtable violates layering by saving (and not correctly managing)
rtes/lles. Instead of passing lle pointer, pass pointer to pre-calculated
header data from that lle.
Differential Revision: https://reviews.freebsd.org/D4102
Before the change, things like lle state were queried via
SIOCGNBRINFO_IN6 by ndp(8) for _each_ lle entry in dump.
This ioctl was added in 1999, probably to avoid touching rtsock code.
This change maps SIOCGNBRINFO_IN6 data to standard rtsock dump the
following way:
expire (already) maps to rtm_rmx.rmx_expire
isrouter -> rtm_flags & RTF_GATEWAY
asked -> rtm_rmx.rmx_pksent
state -> rtm_rmx.rmx_state (maps to rmx_weight via define)
Reviewed by: ae
Vast majority of rtalloc(9) users require only basic info from
route table (e.g. "does the rtentry interface match with the interface
I have?". "what is the MTU?", "Give me the IPv4 source address to use",
etc..).
Instead of hand-rolling lookups, checking if rtentry is up, valid,
dealing with IPv6 mtu, finding "address" ifp (almost never done right),
provide easy-to-use API hiding all the complexity and returning the
needed info into small on-stack structure.
This change also helps hiding route subsystem internals (locking, direct
rtentry accesses).
Additionaly, using this API improves lookup performance since rtentry is not
locked.
(This is safe, since all the rtentry changes happens under both radix WLOCK
and rtentry WLOCK).
Sponsored by: Yandex LLC
by filter function instead of picking into routing table details in
each consumer.
Remove now-unused rt_expunge() (eliminating last external RTF_RNH_LOCKED
user).
This simplifies future nexthops/mulitipath changes and rtrequest1_fib()
locking refactoring.
Actual changes:
Add "rt_chain" field to permit rte grouping while doing batched delete
from routing table (thus growing rte 200->208 on amd64).
Add "rti_filter" / "rti_filterdata" / "rti_spare" fields to rt_addrinfo
to pass filter function to various routing subsystems in standard way.
Convert all rt_expunge() customers to new rt_addinfo-based api and eliminate
rt_expunge().
Some places in our network stack already have const
arguments (like if_output() routines and LLE functions).
Code using ifa_ifwith (and similar functins) along with
LLE/_output functions is currently bound to use tricks
like __DECONST(). Provide a cleaner way by making sockaddr
lookup key really constant.
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D3464
* Move interface route cleanup to route.c:rt_flushifroutes()
* Convert most of "for (fibnum = 0; fibnum < rt_numfibs; fibnum++)" users
to use new rt_foreach_fib() instead of hand-rolling cycles.
Update route MTU in case of ifnet MTU change.
Add new RTF_FIXEDMTU to track explicitly specified MTU.
Old behavior:
ifconfig em0 mtu 1500->9000 -> all routes traversing em0 do not change MTU.
User has to manually update all routes.
ifconfig em0 mtu 9000->1500 -> all routes traversing em0 do not change MTU.
However, if ip[6]_output finds route with rt_mtu > interface mtu, rt_mtu
gets updated.
New behavior:
ifconfig em0 mtu 1500->9000 -> all interface routes in all fibs gets updated
with new MTU unless RTF_FIXEDMTU flag set on them.
ifconfig em0 mtu 9000->1500 -> all routes in all fibs gets updated with new
MTU unless RTF_FIXEDMTU flag set on them AND rt_mtu is less than ifp mtu.
route add ... -mtu XXX automatically sets RTF_FIXEDMTU flag.
route change .. -mtu 0 automatically removes RTF_FIXEDMTU flag.
PR: 194238
MFC after: 1 month
CR: D1125
All rtsock-initiated rte creation/modification are now
performed in route.c holding radix tree write lock.
This reduces the need for per-rte mutex.
Sponsored by: Yandex LLC
MFC after: 1 month
after r262763 it started to return locked mutexes to UMA. To fix that,
conditionally unlock the mutex in the destructor.
Tested by: "Sergey V. Dyatko" <sergey.dyatko@gmail.com>
- Use counter(9) for rt_pksent (former rt_rmx.rmx_pksent). This
removes another cache trashing ++ from packet forwarding path.
- Create zini/fini methods for the rtentry UMA zone. Via initialize
mutex and counter in them.
- Fix reporting of rmx_pksent to routing socket.
- Fix netstat(1) to report "Use" both in kvm(3) and sysctl(3) mode.
The change is mostly targeted for stable/10 merge. For head,
rt_pksent is expected to just disappear.
Discussed with: melifaro
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
has the same prefix as some other alias on the same interface, use
newly-added rt_addrmsg() instead of hand-rolled in_addralias_rtmsg().
This eliminates the following rtsock messages:
Pinned RTM_ADD for prefix (for alias addition).
Pinned RTM_DELETE for prefix (for alias withdrawal).
Example (got 10.0.0.1/24 on vlan4, playing with 10.0.0.2/24):
before commit, addition:
got message of size 116 on Fri Jan 10 14:13:15 2014
RTM_NEWADDR: address being added to iface: len 116, metric 0, flags:
sockaddrs: <NETMASK,IFP,IFA,BRD>
255.255.255.0 vlan4:8.0.27.c5.29.d4 10.0.0.2 10.0.0.255
got message of size 192 on Fri Jan 10 14:13:15 2014
RTM_ADD: Add Route: len 192, pid: 0, seq 0, errno 0, flags:<UP,PINNED>
locks: inits:
sockaddrs: <DST,GATEWAY,NETMASK>
10.0.0.0 10.0.0.2 (255) ffff ffff ff
after commit, addition:
got message of size 116 on Fri Jan 10 13:56:26 2014
RTM_NEWADDR: address being added to iface: len 116, metric 0, flags:
sockaddrs: <NETMASK,IFP,IFA,BRD>
255.255.255.0 vlan4:8.0.27.c5.29.d4 14.0.0.2 14.0.0.255
before commit, wihdrawal:
got message of size 192 on Fri Jan 10 13:58:59 2014
RTM_DELETE: Delete Route: len 192, pid: 0, seq 0, errno 0, flags:<UP,PINNED>
locks: inits:
sockaddrs: <DST,GATEWAY,NETMASK>
10.0.0.0 10.0.0.2 (255) ffff ffff ff
got message of size 116 on Fri Jan 10 13:58:59 2014
RTM_DELADDR: address being removed from iface: len 116, metric 0, flags:
sockaddrs: <NETMASK,IFP,IFA,BRD>
255.255.255.0 vlan4:8.0.27.c5.29.d4 10.0.0.2 10.0.0.255
adter commit, withdrawal:
got message of size 116 on Fri Jan 10 14:14:11 2014
RTM_DELADDR: address being removed from iface: len 116, metric 0, flags:
sockaddrs: <NETMASK,IFP,IFA,BRD>
255.255.255.0 vlan4:8.0.27.c5.29.d4 10.0.0.2 10.0.0.255
Sending both RTM_ADD/RTM_DELETE messages to rtsock is completely wrong
(and requires some hacks to keep prefix in route table on RTM_DELETE).
I've tested this change with quagga (no change) and bird (*).
bird alias handling is already broken in *BSD sysdep code, so nothing
changes here, too.
I'm going to MFC this change if there will be no complains about behavior
change.
While here, fix some style(9) bugs introduced by r260488
(pointed by glebius and bde).
Sponsored by: Yandex LLC
MFC after: 4 weeks
Adding/deleting interface addresses involves access to 3 different subsystems,
int different parts of code. Each call can fail, so reporting successful
operation by rtsock in the middle of the process error-prone.
Further split routing notification API and actual rtsock calls via creating
public-available rt_addrmsg() / rt_routemsg() functions with "private"
rtsock_* backend.
MFC after: 2 weeks
in FBSD 8.0, interface routes have been returened to the
applications without the RTF_GATEWAY bit. This incompatibility
has caused some issues with Zebra, Qugga and the like.
This patch provides the RTF_GATEWAY flag bit in returned interface
routes so to behave similarly to pre 8.0 systems.
Reviewed by: hrs
Verified by: mackn at opendns dot com
Use RTM_PINNED flag to mark route as immutable.
Forbid deleting immutable routes without special rtrequest1_fib() flag.
Adding interface address with prefix already in route table is handled
by atomically deleting old prefix and adding interface one.
Discussed with: andre, eri
MFC after: 3 weeks
it skips FLOWTABLE lookup. However, the non-NULL ro has dual meaning
here: it may be supplied to provide route, and it may be supplied to
store and return to caller the route that ip_output()/ip6_output()
finds. In the latter case skipping FLOWTABLE lookup is pessimisation.
The difference between struct route filled by FLOWTABLE and filled
by rtalloc() family is that the former doesn't hold a reference on
its rtentry. Reference is hold by flow entry, and it is about to
be released in future. Thus, route filled by FLOWTABLE shouldn't
be passed to RTFREE() macro.
- Introduce new flag for struct route/route_in6, that marks route
not holding a reference on rtentry.
- Introduce new macro RO_RTFREE() that cleans up a struct route
depending on its kind.
- All callers to ip_output()/ip6_output() that do supply non-NULL
but empty route should use RO_RTFREE() to free results of
lookup.
- ip_output()/ip6_output() now do FLOWTABLE lookup always when
ro->ro_rt == NULL.
Tested by: tuexen (SCTP part)
rather than the header file. With this also move RT_MAXFIBS and
RT_NUMFIBS into the implemantion to avoid further usage in other
code. rt_numfibs is all that should be needed.
This allows users to change the number of FIBs from 1..RT_MAXFIBS(16)
dynamically using the tunable without the need to change the kernel
config for the maximum anymore. This means that thet multi-FIB
feature is now fully available with GENERIC kernels.
The kernel option ROUTETABLES can still be used to set the default
numbers of FIBs in absence of the tunable.
Ok.ed by: julian, hrs, melifaro
MFC after: 2 weeks
the (maximum) number of FIBs trying to clarify that evetually FIBs
should probably attached to domain(9) specific storage. [1]
Add a comment on a limitimation on the rt_add_addr_allfibs option.
Use RT_DEFAULT_FIB instead of 0 where applicable.
Add empty line to functions without local variables per style.
Put public yet unused in-tree function rtinit_fib() under BURN_BRIDGES
to indicate that it might go away in the future.
No functional change.
Discussed with: julian [1] (clarification on what the original one meant)
Sponsored by: Cisco Systems, Inc.
rtsock allowing routing daemons to filter routing updates on an
rtsock per FIB.
Adjust raw_input() and split it into wrapper and a new function
taking an optional callback argument even though we only have one
consumer [1] to keep the hackish flags local to rtsock.c.
PR: kern/134931
Submitted by: multiple (see PR)
Suggested by: rwatson [1]
Reviewed by: rwatson
MFC after: 3 days
if the interface has such capability. The interface
capability flag indicates whether such capability
exists. This approach is much more backward compatible.
Physical device driver changes will be part of another
commit.
Also updated the ifconfig utility to show the LINKSTATE
capability if present.
Reviewed by: rwatson, imp, juli
MFC after: 3 days
does not set or update the if_link_state variable.
As such RT_LINK_IS_UP() fails for the if_tap interface.
Also, the RT_LINK_IS_UP() needs to bypass all loopback
interfaces because loopback interfaces are considered
up logically as long as the system is running.
This patch fixes the above issues by setting and updating
the if_link_state variable when the tap interface is
opened or closed respectively. Similary approach is
already done in the if_tun device.
MFC after: 3 days
allow for connection load balancing across interfaces. Currently
the address alias handling method is colliding with the ECMP code.
For example, when two interfaces are configured on the same prefix,
only one prefix route is installed. So connection load balancing
among the available interfaces is not possible.
The other advantage of ECMP is for failover. The issue with the
current code, is that the interface link-state is not reflected
in the route entry. For example, if there are two interfaces on
the same prefix, the cable on one interface is unplugged, new and
existing connections should switch over to the other interface.
This is not done today and packets go into a black hole.
Also, there is a small bug in the kernel where deleting ECMP routes
in the userland will always return an error even though the command
is successfully executed.
MFC after: 5 days
IFF_POINTOPOINT link types. The reason was due to the routing
entry returned from the kernel covering the remote end is of an
interface type that does not support ARP. This patch fixes this
problem by providing a hint to the kernel routing code, which
indicates the prefix route instead of the PPP host route should
be returned to the caller. Since a host route to the local end
point is also added into the routing table, and there could be
multiple such instantiations due to multiple PPP links can be
created with the same local end IP address, this patch also fixes
the loopback route installation failure problem observed prior to
this patch. The reference count of loopback route to local end would
be either incremented or decremented. The first instantiation would
create the entry and the last removal would delete the route entry.
MFC after: 5 days
has not worked since the arp-v2 rewrite.
The event handler will be called with the llentry write-locked and
can examine la_flags to determine whether the entry is being added
or removed.
Reviewed by: gnn, kmacy
Approved by: gnn (mentor)
MFC after: 1 month
No longer export rt_tables as all lookups go through
rt_tables_get_rnh().
We cannot make rt_tables (and rtstat, rttrash[1]) static as
netstat -r (-rs[1]) would stop working on a stripped
VIMAGE_GLOBALS kernel.
Reviewed by: zec
Presumably broken by: phk 13.5y ago in r12820 [1]
an accessor function to get the correct rnh pointer back.
Update netstat to get the correct pointer using kvm_read()
as well.
This not only fixes the ABI problem depending on the kernel
option but also permits the tunable to overwrite the kernel
option at boot time up to MAXFIBS, enlarging the number of
FIBs without having to recompile. So people could just use
GENERIC now.
Reviewed by: julian, rwatson, zec
X-MFC: not possible
- add show as alias for get
- add weights to allow mpath to do more than equal cost
- add sticky / nostick to disable / re-enable per-connection load balancing
This adds a field to rt_metrics_lite so network bits of world will need to be re-built.
Reviewed by: jeli & qingli
by the new kernel option COMPAT_ROUTE_FLAGS for binary backward
compatibility. The RTF_LLDATA flag maps to the same value as RTF_LLINFO.
RTF_LLDATA is used by the arp and ndp utilities. The RTF_LLDATA flag is
always returned to the userland regardless whether the COMPAT_ROUTE_FLAGS
is defined.
1. The "route" command allows route insertion through the interface-direct
option "-iface". During if_attach(), an sockaddr_dl{} entry is created
for the interface and is part of the interface address list. This
sockaddr_dl{} entry describes the interface in detail. The "route"
command selects this entry as the "gateway" object when the "-iface"
option is present. The "arp" and "ndp" commands also interact with the
kernel through the routing socket when adding and removing static L2
entries. The static L2 information is also provided through the
"gateway" object with an AF_LINK family type, similar to what is
provided by the "route" command. In order to differentiate between
these two types of operations, a RTF_LLDATA flag is introduced. This
flag is set by the "arp" and "ndp" commands when issuing the add and
delete commands. This flag is also set in each L2 entry returned by the
kernel. The "arp" and "ndp" command follows a convention where a RTM_GET
is issued first followed by a RTM_ADD/DELETE. This RTM_GET request fills
in the fields for a "rtm" object, which is reinjected into the kernel by
a subsequent RTM_ADD/DELETE command. The entry returend from RTM_GET
is a prefix route, so the RTF_LLDATA flag must be specified when issuing
the RTM_ADD/DELETE messages.
2. Enforce the convention that NET_RT_FLAGS with a 0 w_arg is the
specification for retrieving L2 information. Also optimized the
code logic.
Reviewed by: julian
1. separating L2 tables (ARP, NDP) from the L3 routing tables
2. removing as much locking dependencies among these layers as
possible to allow for some parallelism in the search operations
3. simplify the logic in the routing code,
The most notable end result is the obsolescent of the route
cloning (RTF_CLONING) concept, which translated into code reduction
in both IPv4 ARP and IPv6 NDP related modules, and size reduction in
struct rtentry{}. The change in design obsoletes the semantics of
RTF_CLONING, RTF_WASCLONE and RTF_LLINFO routing flags. The userland
applications such as "arp" and "ndp" have been modified to reflect
those changes. The output from "netstat -r" shows only the routing
entries.
Quite a few developers have contributed to this project in the
past: Glebius Smirnoff, Luigi Rizzo, Alessandro Cerri, and
Andre Oppermann. And most recently:
- Kip Macy revised the locking code completely, thus completing
the last piece of the puzzle, Kip has also been conducting
active functional testing
- Sam Leffler has helped me improving/refactoring the code, and
provided valuable reviews
- Julian Elischer setup the perforce tree for me and has helped
me maintaining that branch before the svn conversion
rt_check() in its original form proved to be sufficient and
rt_check_fib() can go away (as can its evil twin in_rt_check()).
I believe this does NOT address the crashes people have been seeing
in rt_check.
MFC after: 1 week
This particular implementation is designed to be fully backwards compatible
and to be MFC-able to 7.x (and 6.x)
Currently the only protocol that can make use of the multiple tables is IPv4
Similar functionality exists in OpenBSD and Linux.
From my notes:
-----
One thing where FreeBSD has been falling behind, and which by chance I
have some time to work on is "policy based routing", which allows
different
packet streams to be routed by more than just the destination address.
Constraints:
------------
I want to make some form of this available in the 6.x tree
(and by extension 7.x) , but FreeBSD in general needs it so I might as
well do it in -current and back port the portions I need.
One of the ways that this can be done is to have the ability to
instantiate multiple kernel routing tables (which I will now
refer to as "Forwarding Information Bases" or "FIBs" for political
correctness reasons). Which FIB a particular packet uses to make
the next hop decision can be decided by a number of mechanisms.
The policies these mechanisms implement are the "Policies" referred
to in "Policy based routing".
One of the constraints I have if I try to back port this work to
6.x is that it must be implemented as a EXTENSION to the existing
ABIs in 6.x so that third party applications do not need to be
recompiled in timespan of the branch.
This first version will not have some of the bells and whistles that
will come with later versions. It will, for example, be limited to 16
tables in the first commit.
Implementation method, Compatible version. (part 1)
-------------------------------
For this reason I have implemented a "sufficient subset" of a
multiple routing table solution in Perforce, and back-ported it
to 6.x. (also in Perforce though not always caught up with what I
have done in -current/P4). The subset allows a number of FIBs
to be defined at compile time (8 is sufficient for my purposes in 6.x)
and implements the changes needed to allow IPV4 to use them. I have not
done the changes for ipv6 simply because I do not need it, and I do not
have enough knowledge of ipv6 (e.g. neighbor discovery) needed to do it.
Other protocol families are left untouched and should there be
users with proprietary protocol families, they should continue to work
and be oblivious to the existence of the extra FIBs.
To understand how this is done, one must know that the current FIB
code starts everything off with a single dimensional array of
pointers to FIB head structures (One per protocol family), each of
which in turn points to the trie of routes available to that family.
The basic change in the ABI compatible version of the change is to
extent that array to be a 2 dimensional array, so that
instead of protocol family X looking at rt_tables[X] for the
table it needs, it looks at rt_tables[Y][X] when for all
protocol families except ipv4 Y is always 0.
Code that is unaware of the change always just sees the first row
of the table, which of course looks just like the one dimensional
array that existed before.
The entry points rtrequest(), rtalloc(), rtalloc1(), rtalloc_ign()
are all maintained, but refer only to the first row of the array,
so that existing callers in proprietary protocols can continue to
do the "right thing".
Some new entry points are added, for the exclusive use of ipv4 code
called in_rtrequest(), in_rtalloc(), in_rtalloc1() and in_rtalloc_ign(),
which have an extra argument which refers the code to the correct row.
In addition, there are some new entry points (currently called
rtalloc_fib() and friends) that check the Address family being
looked up and call either rtalloc() (and friends) if the protocol
is not IPv4 forcing the action to row 0 or to the appropriate row
if it IS IPv4 (and that info is available). These are for calling
from code that is not specific to any particular protocol. The way
these are implemented would change in the non ABI preserving code
to be added later.
One feature of the first version of the code is that for ipv4,
the interface routes show up automatically on all the FIBs, so
that no matter what FIB you select you always have the basic
direct attached hosts available to you. (rtinit() does this
automatically).
You CAN delete an interface route from one FIB should you want
to but by default it's there. ARP information is also available
in each FIB. It's assumed that the same machine would have the
same MAC address, regardless of which FIB you are using to get
to it.
This brings us as to how the correct FIB is selected for an outgoing
IPV4 packet.
Firstly, all packets have a FIB associated with them. if nothing
has been done to change it, it will be FIB 0. The FIB is changed
in the following ways.
Packets fall into one of a number of classes.
1/ locally generated packets, coming from a socket/PCB.
Such packets select a FIB from a number associated with the
socket/PCB. This in turn is inherited from the process,
but can be changed by a socket option. The process in turn
inherits it on fork. I have written a utility call setfib
that acts a bit like nice..
setfib -3 ping target.example.com # will use fib 3 for ping.
It is an obvious extension to make it a property of a jail
but I have not done so. It can be achieved by combining the setfib and
jail commands.
2/ packets received on an interface for forwarding.
By default these packets would use table 0,
(or possibly a number settable in a sysctl(not yet)).
but prior to routing the firewall can inspect them (see below).
(possibly in the future you may be able to associate a FIB
with packets received on an interface.. An ifconfig arg, but not yet.)
3/ packets inspected by a packet classifier, which can arbitrarily
associate a fib with it on a packet by packet basis.
A fib assigned to a packet by a packet classifier
(such as ipfw) would over-ride a fib associated by
a more default source. (such as cases 1 or 2).
4/ a tcp listen socket associated with a fib will generate
accept sockets that are associated with that same fib.
5/ Packets generated in response to some other packet (e.g. reset
or icmp packets). These should use the FIB associated with the
packet being reponded to.
6/ Packets generated during encapsulation.
gif, tun and other tunnel interfaces will encapsulate using the FIB
that was in effect withthe proces that set up the tunnel.
thus setfib 1 ifconfig gif0 [tunnel instructions]
will set the fib for the tunnel to use to be fib 1.
Routing messages would be associated with their
process, and thus select one FIB or another.
messages from the kernel would be associated with the fib they
refer to and would only be received by a routing socket associated
with that fib. (not yet implemented)
In addition Netstat has been edited to be able to cope with the
fact that the array is now 2 dimensional. (It looks in system
memory using libkvm (!)). Old versions of netstat see only the first FIB.
In addition two sysctls are added to give:
a) the number of FIBs compiled in (active)
b) the default FIB of the calling process.
Early testing experience:
-------------------------
Basically our (IronPort's) appliance does this functionality already
using ipfw fwd but that method has some drawbacks.
For example,
It can't fully simulate a routing table because it can't influence the
socket's choice of local address when a connect() is done.
Testing during the generating of these changes has been
remarkably smooth so far. Multiple tables have co-existed
with no notable side effects, and packets have been routes
accordingly.
ipfw has grown 2 new keywords:
setfib N ip from anay to any
count ip from any to any fib N
In pf there seems to be a requirement to be able to give symbolic names to the
fibs but I do not have that capacity. I am not sure if it is required.
SCTP has interestingly enough built in support for this, called VRFs
in Cisco parlance. it will be interesting to see how that handles it
when it suddenly actually does something.
Where to next:
--------------------
After committing the ABI compatible version and MFCing it, I'd
like to proceed in a forward direction in -current. this will
result in some roto-tilling in the routing code.
Firstly: the current code's idea of having a separate tree per
protocol family, all of the same format, and pointed to by the
1 dimensional array is a bit silly. Especially when one considers that
there is code that makes assumptions about every protocol having the
same internal structures there. Some protocols don't WANT that
sort of structure. (for example the whole idea of a netmask is foreign
to appletalk). This needs to be made opaque to the external code.
My suggested first change is to add routing method pointers to the
'domain' structure, along with information pointing the data.
instead of having an array of pointers to uniform structures,
there would be an array pointing to the 'domain' structures
for each protocol address domain (protocol family),
and the methods this reached would be called. The methods would have
an argument that gives FIB number, but the protocol would be free
to ignore it.
When the ABI can be changed it raises the possibilty of the
addition of a fib entry into the "struct route". Currently,
the structure contains the sockaddr of the desination, and the resulting
fib entry. To make this work fully, one could add a fib number
so that given an address and a fib, one can find the third element, the
fib entry.
Interaction with the ARP layer/ LL layer would need to be
revisited as well. Qing Li has been working on this already.
This work was sponsored by Ironport Systems/Cisco
Reviewed by: several including rwatson, bz and mlair (parts each)
Obtained from: Ironport systems/Cisco
(ECMP) for both IPv4 and IPv6. Previously, multipath route insertion
is disallowed. For example,
route add -net 192.103.54.0/24 10.9.44.1
route add -net 192.103.54.0/24 10.9.44.2
The second route insertion will trigger an error message of
"add net 192.103.54.0/24: gateway 10.2.5.2: route already in table"
Multiple default routes can also be inserted. Here is the netstat
output:
default 10.2.5.1 UGS 0 3074 bge0 =>
default 10.2.5.2 UGS 0 0 bge0
When multipath routes exist, the "route delete" command requires
a specific gateway to be specified or else an error message would
be displayed. For example,
route delete default
would fail and trigger the following error message:
"route: writing to routing socket: No such process"
"delete net default: not in table"
On the other hand,
route delete default 10.2.5.2
would be successful: "delete net default: gateway 10.2.5.2"
One does not have to specify a gateway if there is only a single
route for a particular destination.
I need to perform more testings on address aliases and multiple
interfaces that have the same IP prefixes. This patch as it
stands today is not yet ready for prime time. Therefore, the ECMP
code fragments are fully guarded by the RADIX_MPATH macro.
Include the "options RADIX_MPATH" in the kernel configuration
to enable this feature.
Reviewed by: robert, sam, gnn, julian, kmacy
functions. It is easily triggered by running routed, and, I expect, by
running any other daemon that uses routing sockets.
Reviewed by: net@
MFC after: 1 week
- Allow RTM_CHANGE to change a number of route flags as specified by
RTF_FMASK.
- The unused rtm_use field in struct rt_msghdr is redesignated as
rtm_fmask field to communicate route flag changes in RTM_CHANGE
messages from userland. The use count of a route was moved to
rtm_rmx a long time ago. For source code compatibility reasons
a define of rtm_use to rtm_fmask is provided.
These changes faciliate running of multiple cooperating routing
daemons at the same time without causing undesired interference.
Open[BGP|OSPF]D make use of these features to have IGP routes
override EGP ones.
Obtained from: OpenBSD (claudio@)
MFC after: 3 days
This really doesn't belong here but is preferred (for the moment) over
adding yet another mechanism for sending msgs from the kernel to user apps.
Reviewed by: imp
the space occupied by a struct sockaddr when passed through a
routing socket.
Use it to replace the macro ROUNDUP(int), that does the same but
is redefined by every file which uses it, courtesy of
the School of Cut'n'Paste Programming(TM).
(partial) userland changes to follow.
+ struct ifnet: remove unused fields, move ipv6-related field close
to each other, add a pointer to l3<->l2 translation tables (arp,nd6,
etc.) for future use.
+ struct route: remove an unused field, move close to each
other some fields that might likely go away in the future
the routing table. Move all usage and references in the tcp stack
from the routing table metrics to the tcp hostcache.
It caches measured parameters of past tcp sessions to provide better
initial start values for following connections from or to the same
source or destination. Depending on the network parameters to/from
the remote host this can lead to significant speedups for new tcp
connections after the first one because they inherit and shortcut
the learning curve.
tcp_hostcache is designed for multiple concurrent access in SMP
environments with high contention and is hash indexed by remote
ip address.
It removes significant locking requirements from the tcp stack with
regard to the routing table.
Reviewed by: sam (mentor), bms
Reviewed by: -net, -current, core@kame.net (IPv6 parts)
Approved by: re (scottl)
accordingly. The define is left intact for ABI compatibility
with userland.
This is a pre-step for the introduction of tcp_hostcache. The
network stack remains fully useable with this change.
Reviewed by: sam (mentor), bms
Reviewed by: -net, -current, core@kame.net (IPv6 parts)
Approved by: re (scottl)
routine that takes a locked routing table reference and removes all
references to the entry in the various data structures. This
eliminates instances of recursive locking and also closes races
where the lock on the entry had to be dropped prior to calling
rtrequest(RTM_DELETE). This also cleans up confusion where the
caller held a reference to an entry that might have been reclaimed
(and in some cases used that reference).
Supported by: FreeBSD Foundation
that covers updates to the contents. Note this is separate from holding
a reference and/or locking the routing table itself.
Other/related changes:
o rtredirect loses the final parameter by which an rtentry reference
may be returned; this was never used and added unwarranted complexity
for locking.
o minor style cleanups to routing code (e.g. ansi-fy function decls)
o remove the logic to bump the refcnt on the parent of cloned routes,
we assume the parent will remain as long as the clone; doing this avoids
a circularity in locking during delete
o convert some timeouts to MPSAFE callouts
Notes:
1. rt_mtx in struct rtentry is guarded by #ifdef _KERNEL as user-level
applications cannot/do-no know about mutex's. Doing this requires
that the mutex be the last element in the structure. A better solution
is to introduce an externalized version of struct rtentry but this is
a major task because of the intertwining of rtentry and other data
structures that are visible to user applications.
2. There are known LOR's that are expected to go away with forthcoming
work to eliminate many held references. If not these will be resolved
prior to release.
3. ATM changes are untested.
Sponsored by: FreeBSD Foundation
Obtained from: BSD/OS (partly)
o move route_cb to be private to rtsock.c
o replace global static route_proto by locals
o eliminate global #define shorthands for info references
o remove some register decls
o ansi-fy function decls
o move items to be close in scope to their usage
o add rt_dispatch function for dispatching the actual message
o cleanup tangled logic for doing all-but-me msg send
Support by: FreeBSD Foundation
not removing tabs before "__P((", and not outdenting continuation lines
to preserve non-KNF lining up of code with parentheses. Switch to KNF
formatting and/or rewrap the whole prototype in some cases.
socket so that routing daemons and other interested parties
know when an interface is attached/detached.
PR: kern/33747
Obtained from: NetBSD
MFC after: 2 weeks
Have sys/net/route.c:rtrequest1(), which takes ``rt_addrinfo *''
as the argument. Pass rt_addrinfo all the way down to rtrequest1
and ifa->ifa_rtrequest. 3rd argument of ifa->ifa_rtrequest is now
``rt_addrinfo *'' instead of ``sockaddr *'' (almost noone is
using it anyways).
Benefit: the following command now works. Previously we needed
two route(8) invocations, "add" then "change".
# route add -inet6 default ::1 -ifp gif0
Remove unsafe typecast in rtrequest(), from ``rtentry *'' to
``sockaddr *''. It was introduced by 4.3BSD-Reno and never
corrected.
Obtained from: BSD/OS, NetBSD
MFC after: 1 month
PR: kern/28360
