interface pointer, but also a reference to it.
Modify ifioctl() to use ifunit_ref(), holding the reference until
all ioctls, etc, have completed.
This closes a class of reader-writer races in which interfaces
could be removed during long-running ioctls, leading to crashes.
Many other consumers of ifunit() should now use ifunit_ref() to
avoid similar races.
MFC after: 3 weeks
pointers to "dead" implementations that no-op rather than invoking
the device driver. This would generally be unexpected and
possibly quite badly handled by most device drivers after
if_detach() has completed.
Reviewed by: bms
MFC after: 3 weeks
if_alloc(), and portions of data structure destruction from if_detach()
to if_free(). These changes leave more of the struct ifnet in a
safe-to-access condition between alloc and attach, and between detach
and free, and focus on attach/detach as stack usage events rather than
data structure initialization.
Affected fields include the linkstate task queue, if_afdata lock,
address lists, kqueue state, and MAC labels. ifq_attach() ifq_detach()
are not moved as ifq_attach() may use a queue length set by the device
driver between if_alloc() and if_attach().
MFC after: 3 weeks
calls if_free(), and remains set if the refcount is elevated. IF_DYING
skips the bit in the if_flags bitmask previously used by IFF_NEEDSGIANT,
so that an MFC can be done without changing which bit is used, as
IFF_NEEDSGIANT is still present in 7.x.
ifnet_byindex_ref() checks for IFF_DYING and returns NULL if it is set,
preventing new references from by acquired by index, preventing
monitoring sysctls from seeing it. Other lookup mechanisms currently
do not check IFF_DYING, but may need to in the future.
MFC after: 3 weeks
after the corresponding interface has been destroyed:
(1) Add an ifnet refcount, ifp->if_refcount. Initialize it to 1 in
if_alloc(), and modify if_free_type() to decrement and check the
refcount.
(2) Add new if_ref() and if_rele() interfaces to allow kernel code
walking global interface lists to release IFNET_[RW]LOCK() yet
keep the ifnet stable. Currently, if_rele() is a no-op wrapper
around if_free(), but this may change in the future.
(3) Add new ifnet field, if_alloctype, which caches the type passed
to if_alloc(), but unlike if_type, won't be changed by drivers.
This allows asynchronous free's of the interface after the
driver has released it to still use the right type. Use that
instead of the type passed to if_free_type(), but assert that
they are the same (might have to rethink this if that doesn't
work out).
(4) Add a new ifnet_byindex_ref(), which looks up an interface by
index and returns a reference rather than a pointer to it.
(5) Fix if_alloc() to fully initialize the if_addr_mtx before hooking
up the ifnet to global lists.
(6) Modify sysctls in if_mib.c to use ifnet_byindex_ref() and release
the ifnet when done.
When this change is MFC'd, it will need to replace if_ispare fields
rather than adding new fields in order to avoid breaking the binary
interface. Once this change is MFC'd, if_free_type() should be
removed, as its 'type' argument is now optional.
This refcount is not appropriate for counting mbuf pkthdr references,
and also not for counting entry into the device driver via ifnet
function pointers. An rmlock may be appropriate for the latter.
Rather, this is about ensuring data structure stability when reaching
an ifnet via global ifnet lists and tables followed by copy in or out
of userspace.
MFC after: 3 weeks
Reported by: mdtancsa
Reviewed by: brooks
- fix bug where tail pointer of the free list would not get advanced
- clear entry's next pointer when it is added to the freelist to avoid freeing
an entry that it still points to
as well as providing stateful load balancing when used with RADIX_MPATH.
- Currently compiled in to i386 and amd64 but disabled by default, it can be enabled at
runtime with 'sysctl net.inet.flowtable.enable=1'.
- Embedded users can remove it entirely from the kernel by adding 'nooption FLOWTABLE' to
their kernel config files.
- A minimal hookup will be added to ip_output in a subsequent commit. I would like to see
more review before bringing in changes that require more churn.
Supported by: Bitgravity Inc.
- 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
IPSTAT_INC(), IPSTAT_SUB(), and IPSTAT_DEC(), rather than directly
manipulating the fields across the kernel. This will make it easier
to change the implementation of these statistics, such as using
per-CPU versions of the data structures.
MFC after: 3 days
dependency tracking and ordering enforcement.
With this change, per-vnet initialization functions introduced with
r190787 are no longer directly called from traditional initialization
functions (which cc in most cases inlined to pre-r190787 code), but are
instead registered via the vnet framework first, and are invoked only
after all prerequisite modules have been initialized. In the long run,
this framework should allow us to both initialize and dismantle
multiple vnet instances in a correct order.
The problem this change aims to solve is how to replay the
initialization sequence of various network stack components, which
have been traditionally triggered via different mechanisms (SYSINIT,
protosw). Note that this initialization sequence was and still can be
subtly different depending on whether certain pieces of code have been
statically compiled into the kernel, loaded as modules by boot
loader, or kldloaded at run time.
The approach is simple - we record the initialization sequence
established by the traditional mechanisms whenever vnet_mod_register()
is called for a particular vnet module. The vnet_mod_register_multi()
variant allows a single initializer function to be registered multiple
times but with different arguments - currently this is only used in
kern/uipc_domain.c by net_add_domain() with different struct domain *
as arguments, which allows for protosw-registered initialization
routines to be invoked in a correct order by the new vnet
initialization framework.
For the purpose of identifying vnet modules, each vnet module has to
have a unique ID, which is statically assigned in sys/vimage.h.
Dynamic assignment of vnet module IDs is not supported yet.
A vnet module may specify a single prerequisite module at registration
time by filling in the vmi_dependson field of its vnet_modinfo struct
with the ID of the module it depends on. Unless specified otherwise,
all vnet modules depend on VNET_MOD_NET (container for ifnet list head,
rt_tables etc.), which thus has to and will always be initialized
first. The framework will panic if it detects any unresolved
dependencies before completing system initialization. Detection of
unresolved dependencies for vnet modules registered after boot
(kldloaded modules) is not provided.
Note that the fact that each module can specify only a single
prerequisite may become problematic in the long run. In particular,
INET6 depends on INET being already instantiated, due to TCP / UDP
structures residing in INET container. IPSEC also depends on INET,
which will in turn additionally complicate making INET6-only kernel
configs a reality.
The entire registration framework can be compiled out by turning on the
VIMAGE_GLOBALS kernel config option.
Reviewed by: bz
Approved by: julian (mentor)
when using the "self" keyword in tables or as ()-style host address and
fixes "ifconfig -g all" output.
PR: kern/130977, kern/131310
Submitted by: Mikolaj Golub
MFC after: 3 days
from existing functions for initializing global state.
At this stage, the new per-vnet initializer functions are
directly called from the existing global initialization code,
which should in most cases result in compiler inlining those
new functions, hence yielding a near-zero functional change.
Modify the existing initializer functions which are invoked via
protosw, like ip_init() et. al., to allow them to be invoked
multiple times, i.e. per each vnet. Global state, if any,
is initialized only if such functions are called within the
context of vnet0, which will be determined via the
IS_DEFAULT_VNET(curvnet) check (currently always true).
While here, V_irtualize a few remaining global UMA zones
used by net/netinet/netipsec networking code. While it is
not yet clear to me or anybody else whether this is the right
thing to do, at this stage this makes the code more readable,
and makes it easier to track uncollected UMA-zone-backed
objects on vnet removal. In the long run, it's quite possible
that some form of shared use of UMA zone pools among multiple
vnets should be considered.
Bump __FreeBSD_version due to changes in layout of structs
vnet_ipfw, vnet_inet and vnet_net.
Approved by: julian (mentor)
Not only did these two drivers depend on IFF_NEEDSGIANT, they were
broken 7 months ago during the MPSAFE TTY import. if_ppp(4) has been
replaced by ppp(8). There is no replacement for if_sl(4).
If we see regressions in for example the ports tree, we should just use
__FreeBSD_version 800045 to check whether if_ppp(4) and if_sl(4) are
present. Version 800045 is used to denote the import of MPSAFE TTY.
Discussed with: rwatson, but also rwatson's IFF_NEEDSGIANT emails on the
lists.
handle the ioctl. There are other paths that already call it, but this
allows for a non-interface socket (like AF_LOCAL which ifconfig now
uses) to use a broader class of interface ioctls.
Approved by: bz (mentor), rwatson
no-op's that I inadvertently added. Even if locking is needed in general
for the ioctl's, setting a single long will not need it due to the operation
being atomic.
Reported by: rwatson
LO_CSUM_FEATURES - a bitmask of supported transmit offload features, which
will be stored in if_hwassist if IFCAP_TXCSUM is enabled, and be cleared
from mbuf packet header csum flags on transmit. (1)
LO_CSUM_SET - a bitmask of supported receive offload features, which will
be set on the mbuf packet header csum flags on transmit if IFCAP_RXCSUM
is enabled.
While here, fix SCTP offload for loopback: offer generation on the
transmit side, don't just skip validation on the receive side.
Obtained from: DragonflyBSD (1)
MFC after: 1 week
have its MTU set higher than 1500 (ETHERMTU). Its new limit is now
65535 as enforced by ifhwioctl() in if.c
This allows a tap(4) device to be added to a bridge, which requires all
interface members to have the same MTU, with an interface configured for
jumbo frames. QEMU may now connect to a network via tap(4) without
requiring the real interface to have its MTU set to 1500 or lower.
Reviewed by: rpaulo, bms
MFC after: 1 week
avoidance:
- Enable setting the RXCSUM and TXCSUM flags for loopback interfaces;
set both by default.
- When RXCSUM is set, flag packets sent over the loopback interface as
having checked and valid IP, UDP, TCP checksums so that higher
protocol layers won't check them.
- Always clear CSUM_{IP,UDP_TCP} checksum required flags on transmit,
as they will have gotten there as a result of TXCSUM being set.
This is done only for packets explicitly sent over the loopback, not
simulated loopback via if_simloop() due to !SIMPLEX interfaces, etc.
Note that enabling TXCSUM but not RXCSUM will lead to unhappiness, as
checksums won't be generated but will be validated.
Kris reports that this leads to significant performance improvements
in loopback benchmarking with TCP and UDP for throughput:
RXCSUM RXCSUM+TXCSUM
TCP 15% 37%
UDP 10% 74%
Update man page.
Reviewed by: sam
Tested by: kris
MFC after: 1 week
in FreeBSD 5.x to allow network device drivers to run with Giant
despite the network stack being Giant-free. This significantly
simplifies calls into ioctl() on network interfaces, especially
in the multicast code, as well as eliminates deferred invocation
of interface if_start routines.
Disable the build on device drivers still depending on
IFF_NEEDSGIANT as they no longer compile. They will be removed
in a few weeks if they haven't been made MPSAFE in that time.
Disabled drivers:
if_ar
if_axe
if_aue
if_cdce
if_cue
if_kue
if_ray
if_rue
if_rum
if_sr
if_udav
if_ural
if_zyd
Drivers that were already disabled because of tty changes:
if_ppp
if_sl
Discussed on: arch@
consumers which fork after the shared pages have been setup. pflogd(8)
is an example. The problem is understood and there is a fix coming in
shortly.
Folks who want to continue using it can do so by setting
net.bpf.zerocopy_enable
to 1.
Discussed with: rwatson
are not currently owned by userspace before clearing or rotating them.
Otherwise we may not play by the rules of the shared memory protocol,
potentially corrupting packet data or causing userspace applications
that are playing by the rules to spin due to being notified that a
buffer is complete but the shared memory header not reflecting that.
This behavior was seen with pflogd by a number of reporters; note that
this fix is not sufficient to get pflogd properly working with
zero-copy BPF, due to pflogd opening the BPF device before forking,
leading to the shared memory buffer not being propery inherited in the
privilege-separated child. We're still deciding how to fix that
problem.
This change exposes buffer-model specific strategy information in
reset_d(), which will be fixed at a later date once we've decided how
best to improve the BPF buffer abstraction.
Reviewed by: csjp
Reported by: keramida
