MFC r306577 r306652 306830

Add GARP retransmit capability

A single gratuitous ARP (GARP) is always transmitted when an IPv4
address is added to an interface, and that is usually sufficient.
However, in some circumstances, such as when a shared address is
passed between cluster nodes, this single GARP may occasionally be
dropped or lost. This can lead to neighbors on the network link
working with a stale ARP cache and sending packets destined for
that address to the node that previously owned the address, which
may not respond.

To avoid this situation, GARP retransmissions can be enabled by setting
the net.link.ether.inet.garp_rexmit_count sysctl to a value greater
than zero. The setting represents the maximum number of retransmissions.
The interval between retransmissions is calculated using an exponential
backoff algorithm, doubling each time, so the retransmission intervals
are: {1, 2, 4, 8, 16, ...} (seconds).

Due to the exponential backoff algorithm used for the interval
between GARP retransmissions, the maximum number of retransmissions
is limited to 16 for sanity. This limit corresponds to a maximum
interval between retransmissions of 2^16 seconds ~= 18 hours.
Increasing this limit is possible, but sending out GARPs spaced
days apart would be of little use.

Update arp(4) to document the net.link.ether.inet.garp_rexmit_count sysctl.

Submitted by: dab
Relnotes: yes
Sponsored by: Dell EMC

MFC of r278472
This fixes a bug in the way that the LLE timers for nd6
and arp were being used. They basically would pass in the
mutex to the callout_init. Because they used this method
to the callout system, it was possible to "stop" the callout.
When flushing the table and you stopped the running callout, the
callout_stop code would return 1 indicating that it was going
to stop the callout (that was about to run on the callout_wheel blocked
by the function calling the stop). Now when 1 was returned, it would
lower the reference count one extra time for the stopped timer, then
a few lines later delete the memory. Of course the callout_wheel was
stuck in the lock code and would then crash since it was accessing
freed memory. By using callout_init(c, 1) we always get a 0 back
and the reference counting bug does not rear its head. We do have
to make a few adjustments to the callouts themselves though to make
sure it does the proper thing if rescheduled as well as gets the lock.

Sponsored by: Netflix Inc.

MFC changes related to PR kern/189089. Unlike CURRENT, stable/10 does not
panic when you attempt to remove the IP address. But it still fails to
remove the address.

MFC r265094

Add regression test for PR kern/189088.

MFC r265092

Fix a panic when removing an IP address from an interface, if the same
address exists on another interface. The panic was introduced by change
264887, which changed the fibnum parameter in the call to rtalloc1_fib() in
ifa_switch_loopback_route() from RT_DEFAULT_FIB to RT_ALL_FIBS. The
solution is to use the interface fib in that call. For the majority of
users, that will be equivalent to the legacy behavior.

MFC r264887

Fix host and network routes for new interfaces when net.add_addr_allfibs=0

sys/net/route.c
In rtinit1, use the interface fib instead of the process fib. The
latter wasn't very useful because ifconfig(8) is usually invoked
with the default process fib. Changing ifconfig(8) to use setfib(2)
would be redundant, because it already sets the interface fib.

tests/sys/netinet/fibs_test.sh
Clear the expected ATF failure

sys/net/if.c
Pass the interface fib in calls to rtrequest1_fib and rtalloc1_fib

sys/netinet/in.c
sys/net/if_var.h
Add a fibnum argument to ifa_switch_loopback_route, a subroutine of
in_scrubprefix. Pass it the interface fib.

MFC changes relating to running multiple interfaces on different fibs but
with addresses on the same subnet.

MFC r266860

Fix unintended KBI change from r264905. Add _fib versions of
ifa_ifwithnet() and ifa_ifwithdstaddr() The legacy functions will call the
_fib() versions with RT_ALL_FIBS, preserving legacy behavior.

sys/net/if_var.h
sys/net/if.c
Add legacy-compatible functions as described above. Ensure legacy
behavior when RT_ALL_FIBS is passed as fibnum.

sys/netinet/in_pcb.c
sys/netinet/ip_output.c
sys/netinet/ip_options.c
sys/net/route.c
sys/net/rtsock.c
sys/netinet6/nd6.c
Call with _fib() functions if we must use a specific fib, or the
legacy functions otherwise.

tests/sys/netinet/fibs_test.sh
tests/sys/netinet/udp_dontroute.c
Improve the udp_dontroute test. The bug that this test exercises is
that ifa_ifwithnet() will return the wrong address, if multiple
interfaces have addresses on the same subnet but with different
fibs. The previous version of the test only considered one possible
failure mode: that ifa_ifwithnet_fib() might fail to find any
suitable address at all. The new version also checks whether
ifa_ifwithnet_fib() finds the correct address by checking where the
ARP request goes.

MFC r264917

Style fixes, mostly trailing whitespace elimination. No functional change.

MFC r264905

Fix subnet and default routes on different FIBs on the same subnet.

These two bugs are closely related. The root cause is that ifa_ifwithnet
does not consider FIBs when searching for an interface address.

sys/net/if_var.h
sys/net/if.c
Add a fib argument to ifa_ifwithnet and ifa_ifwithdstadddr. Those
functions will only return an address whose interface fib equals the
argument.

sys/net/route.c
Update calls to ifa_ifwithnet and ifa_ifwithdstaddr with fib
arguments.

sys/netinet/in.c
Update in_addprefix to consider the interface fib when adding
prefixes. This will prevent it from not adding a subnet route when
one already exists on a different fib.

sys/net/rtsock.c
sys/netinet/in_pcb.c
sys/netinet/ip_output.c
sys/netinet/ip_options.c
sys/netinet6/nd6.c
Add RT_DEFAULT_FIB arguments to ifa_ifwithdstaddr and ifa_ifwithnet.
In some cases it there wasn't a clear specific fib number to use.
In others, I was unable to test those functions so I chose
RT_DEFAULT_FIB to minimize divergence from current behavior. I will
fix some of the latter changes along with PR kern/187553.

tests/sys/netinet/fibs_test.sh
tests/sys/netinet/udp_dontroute.c
tests/sys/netinet/Makefile
Revert r263738. The udp_dontroute test was right all along.
However, bugs kern/187550 and kern/187553 cancelled each other out
when it came to this test. Because of kern/187553, ifa_ifwithnet
searched the default fib instead of the requested one, but because
of kern/187550, there was an applicable subnet route on the default
fib. The new test added in r263738 doesn't work right, however. I
can verify with dtrace that ifa_ifwithnet returned the wrong address
before I applied this commit, but route(8) miraculously found the
correct interface to use anyway. I don't know how.

Clear expected failure messages for kern/187550 and kern/187552.

MFC r263738

tests/sys/netinet/Makefile
tests/sys/netinet/fibs.sh
Replace fibs:udp_dontroute with fibs:src_addr_selection_by_subnet.
The original test was poorly written; it was actually testing
kern/167947 instead of the desired kern/187553. The root cause of the
bug is that ifa_ifwithnet did not have a fib argument. The new test
more directly targets that behavior.

tests/sys/netinet/udp_dontroute.c
Delete the auxilliary binary used by the old test

MFC r263779

Correct ARP update handling when the routes for network interfaces are
restricted to a single FIB in a multifib system.

Restricting an interface's routes to the FIB to which it is assigned (by
setting net.add_addr_allfibs=0) causes ARP updates to fail with "arpresolve:
can't allocate llinfo for x.x.x.x". This is due to the ARP update code hard
coding it's lookup for existing routing entries to FIB 0.

sys/netinet/in.c:
When dealing with RTM_ADD (add route) requests for an interface, use
the interface's assigned FIB instead of the default (FIB 0).

sys/netinet/if_ether.c:
In arpresolve(), enhance error message generated when an
lla_lookup() fails so that the interface causing the error is
visible in logs.

tests/sys/netinet/fibs_test.sh
Clear ATF expected error.

MFC r264212,r264213,r264248,r265776,r265811,r265909:

- Add support for UDP-Lite protocol (RFC 3828) to IPv4 and IPv6 stacks.
Tested with vlc and a test suite [1].
[1] http://www.erg.abdn.ac.uk/~gerrit/udp-lite/files/udplite_linux.tar.gz

Reviewed by: jhb, glebius, adrian

- Fix a logic bug which prevented the sending of UDP packet with 0 checksum.

- Disable TX checksum offload for UDP-Lite completely. It wasn't used for
partial checksum coverage, but even for full checksum coverage it doesn't
work.

Merge 260488, r260508.

r260488:
Split rt_newaddrmsg_fib() into two different functions.
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.

r260508:
Simplify inet alias handling code: if we're adding/removing alias which
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).

MFC r260151 (by adrian):
Use an RLOCK here instead of an RWLOCK - matching all the other calls
to lla_lookup().

This drastically reduces the very high lock contention when doing parallel
TCP throughput tests (> 1024 sockets) with IPv6.

MFC r260187:
lla_lookup() does modification only when LLE_CREATE is specified.
Thus we can use IF_AFDATA_RLOCK() instead of IF_AFDATA_LOCK() when doing
lla_lookup() without LLE_CREATE flag.

MFC r260217:
Add IF_AFDATA_WLOCK_ASSERT() in case lla_lookup() is called with
LLE_CREATE flag.

MFC of r278472
This fixes a bug in the way that the LLE timers for nd6
and arp were being used. They basically would pass in the
mutex to the callout_init. Because they used this method
to the callout system, it was possible to "stop" the callout.
When flushing the table and you stopped the running callout, the
callout_stop code would return 1 indicating that it was going
to stop the callout (that was about to run on the callout_wheel blocked
by the function calling the stop). Now when 1 was returned, it would
lower the reference count one extra time for the stopped timer, then
a few lines later delete the memory. Of course the callout_wheel was
stuck in the lock code and would then crash since it was accessing
freed memory. By using callout_init(c, 1) we always get a 0 back
and the reference counting bug does not rear its head. We do have
to make a few adjustments to the callouts themselves though to make
sure it does the proper thing if rescheduled as well as gets the lock.

Sponsored by: Netflix Inc.

MFC changes related to PR kern/189089. Unlike CURRENT, stable/10 does not
panic when you attempt to remove the IP address. But it still fails to
remove the address.

MFC r265094

Add regression test for PR kern/189088.

MFC r265092

Fix a panic when removing an IP address from an interface, if the same
address exists on another interface. The panic was introduced by change
264887, which changed the fibnum parameter in the call to rtalloc1_fib() in
ifa_switch_loopback_route() from RT_DEFAULT_FIB to RT_ALL_FIBS. The
solution is to use the interface fib in that call. For the majority of
users, that will be equivalent to the legacy behavior.

MFC r264887

Fix host and network routes for new interfaces when net.add_addr_allfibs=0

sys/net/route.c
In rtinit1, use the interface fib instead of the process fib. The
latter wasn't very useful because ifconfig(8) is usually invoked
with the default process fib. Changing ifconfig(8) to use setfib(2)
would be redundant, because it already sets the interface fib.

tests/sys/netinet/fibs_test.sh
Clear the expected ATF failure

sys/net/if.c
Pass the interface fib in calls to rtrequest1_fib and rtalloc1_fib

sys/netinet/in.c
sys/net/if_var.h
Add a fibnum argument to ifa_switch_loopback_route, a subroutine of
in_scrubprefix. Pass it the interface fib.

MFC changes relating to running multiple interfaces on different fibs but
with addresses on the same subnet.

MFC r266860

Fix unintended KBI change from r264905. Add _fib versions of
ifa_ifwithnet() and ifa_ifwithdstaddr() The legacy functions will call the
_fib() versions with RT_ALL_FIBS, preserving legacy behavior.

sys/net/if_var.h
sys/net/if.c
Add legacy-compatible functions as described above. Ensure legacy
behavior when RT_ALL_FIBS is passed as fibnum.

sys/netinet/in_pcb.c
sys/netinet/ip_output.c
sys/netinet/ip_options.c
sys/net/route.c
sys/net/rtsock.c
sys/netinet6/nd6.c
Call with _fib() functions if we must use a specific fib, or the
legacy functions otherwise.

tests/sys/netinet/fibs_test.sh
tests/sys/netinet/udp_dontroute.c
Improve the udp_dontroute test. The bug that this test exercises is
that ifa_ifwithnet() will return the wrong address, if multiple
interfaces have addresses on the same subnet but with different
fibs. The previous version of the test only considered one possible
failure mode: that ifa_ifwithnet_fib() might fail to find any
suitable address at all. The new version also checks whether
ifa_ifwithnet_fib() finds the correct address by checking where the
ARP request goes.

MFC r264917

Style fixes, mostly trailing whitespace elimination. No functional change.

MFC r264905

Fix subnet and default routes on different FIBs on the same subnet.

These two bugs are closely related. The root cause is that ifa_ifwithnet
does not consider FIBs when searching for an interface address.

sys/net/if_var.h
sys/net/if.c
Add a fib argument to ifa_ifwithnet and ifa_ifwithdstadddr. Those
functions will only return an address whose interface fib equals the
argument.

sys/net/route.c
Update calls to ifa_ifwithnet and ifa_ifwithdstaddr with fib
arguments.

sys/netinet/in.c
Update in_addprefix to consider the interface fib when adding
prefixes. This will prevent it from not adding a subnet route when
one already exists on a different fib.

sys/net/rtsock.c
sys/netinet/in_pcb.c
sys/netinet/ip_output.c
sys/netinet/ip_options.c
sys/netinet6/nd6.c
Add RT_DEFAULT_FIB arguments to ifa_ifwithdstaddr and ifa_ifwithnet.
In some cases it there wasn't a clear specific fib number to use.
In others, I was unable to test those functions so I chose
RT_DEFAULT_FIB to minimize divergence from current behavior. I will
fix some of the latter changes along with PR kern/187553.

tests/sys/netinet/fibs_test.sh
tests/sys/netinet/udp_dontroute.c
tests/sys/netinet/Makefile
Revert r263738. The udp_dontroute test was right all along.
However, bugs kern/187550 and kern/187553 cancelled each other out
when it came to this test. Because of kern/187553, ifa_ifwithnet
searched the default fib instead of the requested one, but because
of kern/187550, there was an applicable subnet route on the default
fib. The new test added in r263738 doesn't work right, however. I
can verify with dtrace that ifa_ifwithnet returned the wrong address
before I applied this commit, but route(8) miraculously found the
correct interface to use anyway. I don't know how.

Clear expected failure messages for kern/187550 and kern/187552.

MFC r263738

tests/sys/netinet/Makefile
tests/sys/netinet/fibs.sh
Replace fibs:udp_dontroute with fibs:src_addr_selection_by_subnet.
The original test was poorly written; it was actually testing
kern/167947 instead of the desired kern/187553. The root cause of the
bug is that ifa_ifwithnet did not have a fib argument. The new test
more directly targets that behavior.

tests/sys/netinet/udp_dontroute.c
Delete the auxilliary binary used by the old test

MFC r263779

Correct ARP update handling when the routes for network interfaces are
restricted to a single FIB in a multifib system.

Restricting an interface's routes to the FIB to which it is assigned (by
setting net.add_addr_allfibs=0) causes ARP updates to fail with "arpresolve:
can't allocate llinfo for x.x.x.x". This is due to the ARP update code hard
coding it's lookup for existing routing entries to FIB 0.

sys/netinet/in.c:
When dealing with RTM_ADD (add route) requests for an interface, use
the interface's assigned FIB instead of the default (FIB 0).

sys/netinet/if_ether.c:
In arpresolve(), enhance error message generated when an
lla_lookup() fails so that the interface causing the error is
visible in logs.

tests/sys/netinet/fibs_test.sh
Clear ATF expected error.

MFC r264212,r264213,r264248,r265776,r265811,r265909:

- Add support for UDP-Lite protocol (RFC 3828) to IPv4 and IPv6 stacks.
Tested with vlc and a test suite [1].
[1] http://www.erg.abdn.ac.uk/~gerrit/udp-lite/files/udplite_linux.tar.gz

Reviewed by: jhb, glebius, adrian

- Fix a logic bug which prevented the sending of UDP packet with 0 checksum.

- Disable TX checksum offload for UDP-Lite completely. It wasn't used for
partial checksum coverage, but even for full checksum coverage it doesn't
work.

Merge 260488, r260508.

r260488:
Split rt_newaddrmsg_fib() into two different functions.
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.

r260508:
Simplify inet alias handling code: if we're adding/removing alias which
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).

MFC r260151 (by adrian):
Use an RLOCK here instead of an RWLOCK - matching all the other calls
to lla_lookup().

This drastically reduces the very high lock contention when doing parallel
TCP throughput tests (> 1024 sockets) with IPv6.

MFC r260187:
lla_lookup() does modification only when LLE_CREATE is specified.
Thus we can use IF_AFDATA_RLOCK() instead of IF_AFDATA_LOCK() when doing
lla_lookup() without LLE_CREATE flag.

MFC r260217:
Add IF_AFDATA_WLOCK_ASSERT() in case lla_lookup() is called with
LLE_CREATE flag.