compatibility with BIOC[GS]SEESENT ioctl. The userland interface is the same
as FreeBSD.
This change also fixes a bug that the direction is misunderstand on some
environment by passing the direction to bpf_mtap*() instead of checking
m->m_pkthdr.rcvif.
Because recent investigations show that interfaces with IFEF_MPSAFE need to
follow additional restrictions to work with the flag safely. We should enable it
on an interface by default only if the interface surely satisfies the
restrictions, which are described in if.h.
Note that enabling IFEF_MPSAFE solely gains a few benefit on performance because
the network stack is still serialized by the big kernel locks by default.
And ensure to turn off it before destruction as per IFF_RUNNING's description
"resource allocated". (The description is a bit doubtful though, I believe the
change is still proper.)
There are already two flags for if_output and if_start, however, it seems such
MPSAFE flags are eventually needed for all if_XXX operations. Having discrete
flags for each operation is wasteful of if_extflags bits. So let's unify
the flags into one: IFEF_MPSAFE.
Fortunately IFEF_*_MPSAFE flags have never been included in any releases, so
we can change them without breaking backward compatibility of the releases
(though the kernel version of -current should be bumped).
Note that if an interface have both MP-safe and non-MP-safe operations at a
time, we have to set the IFEF_MPSAFE flag and let callees of non-MP-safe
opeartions take the kernel lock.
Proposed on tech-kern@ and tech-net@
kmem_alloc() with KM_SLEEP
kmem_zalloc() with KM_SLEEP
percpu_alloc()
pserialize_create()
psref_class_create()
all of these paths include an assertion that the allocation has not failed,
so callers should not assert that again.
CAN stands for Controller Area Network, a broadcast network used
in automation and automotive fields. For example, the NMEA2000 standard
developped for marine devices uses a CAN network as the link layer.
This is an implementation of the linux socketcan API:
https://www.kernel.org/doc/Documentation/networking/can.txt
you can also see can(4).
This adds a new socket family (AF_CAN) and protocol (PF_CAN),
as well as the canconfig(8) utility, used to set timing parameter of
CAN hardware. Also inclued is a driver for the CAN controller
found in the allwinner A20 SoC (I tested it with an Olimex lime2 board,
connected with PIC18-based CAN devices).
There is also the canloop(4) pseudo-device, which allows to use
the socketcan API without CAN hardware.
At this time the CANFD part of the linux socketcan API is not implemented.
Error frames are not implemented either. But I could get the cansend and
canreceive utilities from the canutils package to build and run with minimal
changes. tcpudmp(8) can also be used to record frames, which can be
decoded with etherreal.
ozaki-r