Persistently store NIC's hardware MAC address, and add a way to retrive it

jhb pointed out that (struct ifnet) is part of the network driver KBI, and
thus the offsets of internal fields must not change. Therefore, move the new
"if_hw_addr" field to the end, and consume one of the "if_pspare"s; that's
what they're there for. Because netmap on stable/10 uses "if_pspare[0]", the
new field replaces the *last* element of that array; that way,
offsetof(if_pspare) is unchanged compared to before r318430.

PR: 194386
Reviewed by: jhb
Pointyhat to: rpokala
Sponsored by: Panasas

MFC r318160, 318176: Persistently store NIC's hardware MAC address, and add
a way to retrive it

NOTE: Due to restructuring, the merges didn't apply cleanly; the resulting
change is almost identical to what went into stable/11, but in some cases in
different locations.

The MAC address reported by `ifconfig ${nic} ether' does not always match
the address in the hardware, as reported by the driver during attach. In
particular, NICs which are components of a lagg(4) interface all report the
same MAC.

When attaching, the NIC driver passes the MAC address it read from the
hardware as an argument to ether_ifattach(). Keep a second copy of it, and
create ioctl(SIOCGHWADDR) to return it. Teach `ifconfig' to report it along
with the active MAC address.

PR: 194386

MFC: r312687, r312916

Approved by: sephe (mentor)

r312687
ifnet: introduce event handlers for ifup/ifdown events

Hyper-V's NIC SR-IOV implementation needs a Hyper-V synthetic NIC and
a VF NIC to work together, mainly to support seamless live migration.

When the VF device becomes UP (or DOWN), the synthetic NIC driver needs
to switch the data path from the synthetic NIC to the VF (or the opposite).

So the synthetic NIC driver needs to know when a VF device is becoming
UP or DOWN and hence the patch is made.

Reviewed by: sephe
Approved by: sephe (mentor)
Sponsored by: Microsoft
Differential Revision: https://reviews.freebsd.org/D8963

r312916
ifnet: move the new ifnet_event EVENTHANDLER_DECLARE to net/if_var.h

Thank glebius for pointing this out:
"The network stuff shall not be added to sys/eventhandler.h"

Reviewed by: David_A_Bright_DELL.com, sephe, glebius
Approved by: sephe (mentor)
Sponsored by: Microsoft
Differential Revision: https://reviews.freebsd.org/D9345

MFC 296178

buf_ring/drbr: Add buf_ring_peek_clear_sc and use it in drbr_peek

Unlike buf_ring_peek, it only supports single consumer mode, and it
clears the cons_head if DEBUG_BUFRING/INVARIANTS is defined.

The normal use case of drbr_peek for network drivers is:

m = drbr_peek(br);
err = hw_spec_encap(&m); /* could m_defrag/m_collapse */
(*)
if (err) {
if (m == NULL)
drbr_advance(br);
else
drbr_putback(br, m);
/* break the loop */
}
drbr_advance(br);

The race is:
If hw_spec_encap() m_defrag or m_collapse the mbuf, i.e. the old mbuf
was freed, or like the Hyper-V's network driver, that transmission-
done does not even require the TX lock; then on the other CPU at the
(*) time, the freed mbuf could be recycled and being drbr_enqueue even
before the current CPU had the chance to call drbr_{advance,putback}.
This triggers a panic in drbr_enqueue duplicated element check, if
DEBUG_BUFRING/INVARIANTS is defined.

Use buf_ring_peek_clear_sc() in drbr_peek() to fix the above race.

This change is a NO-OP, if neither DEBUG_BUFRING nor INVARIANTS are
defined.

MFC after: 1 week
Sponsored by: Microsoft OSTC
Differential Revision: https://reviews.freebsd.org/D5416

MFC r287775:
Update TSO limits to include all headers.

To make driver programming easier the TSO limits are changed to
reflect the values used in the BUSDMA tag a network adapter driver is
using. The TCP/IP network stack will subtract space for all linklevel
and protocol level headers and ensure that the full mbuf chain passed
to the network adapter fits within the given limits. See r287775
for a more detailed description.

Differential Revision: https://reviews.freebsd.org/D3477
Reviewed by: rmacklem

Add if_inc_counter() and if_get_counter_default() functions that do
access to ifnet counters for code compatibility with FreeBSD 11.

This is direct commit to stable/10.

Discussed with: glebius@, arch@

MFC r274376:
Fix some minor TSO issues:
- Improve description of TSO limits.
- Remove a not needed KASSERT()
- Remove some not needed variable casts.

Sponsored by: Mellanox Technologies

MFC r271946 and r272595:
Improve transmit sending offload, TSO, algorithm in general. This
change allows all HCAs from Mellanox Technologies to function properly
when TSO is enabled. See r271946 and r272595 for more details about
this commit.

Sponsored by: Mellanox Technologies

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

Add if_inc_counter() and if_get_counter_default() functions that do
access to ifnet counters for code compatibility with FreeBSD 11.

This is direct commit to stable/10.

Discussed with: glebius@, arch@

MFC r274376:
Fix some minor TSO issues:
- Improve description of TSO limits.
- Remove a not needed KASSERT()
- Remove some not needed variable casts.

Sponsored by: Mellanox Technologies

MFC r271946 and r272595:
Improve transmit sending offload, TSO, algorithm in general. This
change allows all HCAs from Mellanox Technologies to function properly
when TSO is enabled. See r271946 and r272595 for more details about
this commit.

Sponsored by: Mellanox Technologies

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