Debugnet is a simplistic and specialized panic- or debug-time reliable
datagram transport. It can drive a single connection at a time and is
currently unidirectional (debug/panic machine transmit to remote server
only).
It is mostly a verbatim code lift from netdump(4). Netdump(4) remains
the only consumer (until the rest of this patch series lands).
The INET-specific logic has been extracted somewhat more thoroughly than
previously in netdump(4), into debugnet_inet.c. UDP-layer logic and up, as
much as possible as is protocol-independent, remains in debugnet.c. The
separation is not perfect and future improvement is welcome. Supporting
INET6 is a long-term goal.
Much of the diff is "gratuitous" renaming from 'netdump_' or 'nd_' to
'debugnet_' or 'dn_' -- sorry. I thought keeping the netdump name on the
generic module would be more confusing than the refactoring.
The only functional change here is the mbuf allocation / tracking. Instead
of initiating solely on netdump-configured interface(s) at dumpon(8)
configuration time, we watch for any debugnet-enabled NIC for link
activation and query it for mbuf parameters at that time. If they exceed
the existing high-water mark allocation, we re-allocate and track the new
high-water mark. Otherwise, we leave the pre-panic mbuf allocation alone.
In a future patch in this series, this will allow initiating netdump from
panic ddb(4) without pre-panic configuration.
No other functional change intended.
Reviewed by: markj (earlier version)
Some discussion with: emaste, jhb
Objection from: marius
Differential Revision: https://reviews.freebsd.org/D21421
general is allowed to sleep. Don't enter the epoch for the
whole duration. If some event handlers need the epoch, they
should handle that theirselves.
Discussed with: hselasky
same after the network stack was epochified. Merge the two into one function
and cleanup all uses of ifnet_byindex_locked().
While at it:
- Add branch prediction macros.
- Make sure the ifnet pointer is only deferred once,
also when code optimisation is disabled.
Sponsored by: Mellanox Technologies
This fixes the following assert when "options RATELIMIT" is used:
panic()
malloc()
sysctl_add_oid()
tcp_rl_ifnet_link()
do_link_state_change()
taskqueue_run_locked()
Sponsored by: Mellanox Technologies
on interface. Such function could been implemented on top of
the if_foreach_llm?addr(), but several drivers need counting,
so avoid copy-n-paste inside the drivers.
addresses. The KPI doesn't reveal neither how addresses are stored,
how the access to them is synchronized, neither reveal struct ifaddr
and struct ifmaddr.
Reviewed by: gallatin, erj, hselasky, philip, stevek
Differential Revision: https://reviews.freebsd.org/D21943
protected by IF_ADDR_LOCK(), which was a mutex, so that two simultaneous
if_setlladdr() can't execute. Later it was switched to IF_ADDR_RLOCK(),
likely by a mistake. Later it was switched to NET_EPOCH_ENTER(). Then I
incorrectly added NET_EPOCH_ASSERT() here.
In reality ifp->if_addr never goes away and never changes its length. So,
doing bcopy() in it is always "safe", meaning it won't dereference a wrong
pointer or write into someone's else memory. Of course doing two bcopy() in
parallel would result in a mess of two addresses, but net epoch doesn't
protect against that, neither IF_ADDR_RLOCK() did.
So for now, just remove the assertion and leave for later a proper fix.
Reported by: markj
When epoch(9) was introduced to network stack, it was basically
dropped in place of existing locking, which was mutexes and
rwlocks. For the sake of performance mutex covered areas were
as small as possible, so became epoch covered areas.
However, epoch doesn't introduce any contention, it just delays
memory reclaim. So, there is no point to minimise epoch covered
areas in sense of performance. Meanwhile entering/exiting epoch
also has non-zero CPU usage, so doing this less often is a win.
Not the least is also code maintainability. In the new paradigm
we can assume that at any stage of processing a packet, we are
inside network epoch. This makes coding both input and output
path way easier.
On output path we already enter epoch quite early - in the
ip_output(), in the ip6_output().
This patch does the same for the input path. All ISR processing,
network related callouts, other ways of packet injection to the
network stack shall be performed in net_epoch. Any leaf function
that walks network configuration now asserts epoch.
Tricky part is configuration code paths - ioctls, sysctls. They
also call into leaf functions, so some need to be changed.
This patch would introduce more epoch recursions (see EPOCH_TRACE)
than we had before. They will be cleaned up separately, as several
of them aren't trivial. Note, that unlike a lock recursion the
epoch recursion is safe and just wastes a bit of resources.
Reviewed by: gallatin, hselasky, cy, adrian, kristof
Differential Revision: https://reviews.freebsd.org/D19111
Remove the now obsolete vnet_state field. This greatly simplifies the
detection of VNET shutdown and avoids code duplication.
Discussed with: bz@
MFC after: 1 week
Sponsored by: Mellanox Technologies
properly nested and warns about recursive entrances. Unlike with locks,
there is nothing fundamentally wrong with such use, the intent of tracer
is to help to review complex epoch-protected code paths, and we mean the
network stack here.
Reviewed by: hselasky
Sponsored by: Netflix
Pull Request: https://reviews.freebsd.org/D21610
The ioctl(2) is intended to provide more details about the cause of
the down for the link.
Eventually we might define a comprehensive list of codes for the
situations. But interface also allows the driver to provide free-form
null-terminated ASCII string to provide arbitrary non-formalized
information. Sample implementation exists for mlx5(4), where the
string is fetched from firmware controlling the port.
Reviewed by: hselasky, rrs
Sponsored by: Mellanox Technologies
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D21527
Instead of throwing EEXIST, just succeed if the name isn't actually
changing. We don't need to trigger departure or any of that because there's
no change from consumers' perspective.
PR: 240539
Reviewed by: brooks
MFC after: 5 days
Differential Revision: https://reviews.freebsd.org/D21618
network interface.
This particularly manifests itself when an INP has multicast options
attached during a network interface detach. Then the IPv4 and IPv6
leave group call which results from freeing the multicast address, may
access a freed ifnet structure. These are the steps to reproduce:
service mdnsd onestart # installed from ports
ifconfig epair create
ifconfig epair0a 0/24 up
ifconfig epair0a destroy
Tested by: pho @
MFC after: 1 week
Sponsored by: Mellanox Technologies
- Perform ifp mismatch checks (to determine if a send tag is allocated
for a different ifp than the one the packet is being output on), in
ip_output() and ip6_output(). This avoids sending packets with send
tags to ifnet drivers that don't support send tags.
Since we are now checking for ifp mismatches before invoking
if_output, we can now try to allocate a new tag before invoking
if_output sending the original packet on the new tag if allocation
succeeds.
To avoid code duplication for the fragment and unfragmented cases,
add ip_output_send() and ip6_output_send() as wrappers around
if_output and nd6_output_ifp, respectively. All of the logic for
setting send tags and dealing with send tag-related errors is done
in these wrapper functions.
For pseudo interfaces that wrap other network interfaces (vlan and
lagg), wrapper send tags are now allocated so that ip*_output see
the wrapper ifp as the ifp in the send tag. The if_transmit
routines rewrite the send tags after performing an ifp mismatch
check. If an ifp mismatch is detected, the transmit routines fail
with EAGAIN.
- To provide clearer life cycle management of send tags, especially
in the presence of vlan and lagg wrapper tags, add a reference count
to send tags managed via m_snd_tag_ref() and m_snd_tag_rele().
Provide a helper function (m_snd_tag_init()) for use by drivers
supporting send tags. m_snd_tag_init() takes care of the if_ref
on the ifp meaning that code alloating send tags via if_snd_tag_alloc
no longer has to manage that manually. Similarly, m_snd_tag_rele
drops the refcount on the ifp after invoking if_snd_tag_free when
the last reference to a send tag is dropped.
This also closes use after free races if there are pending packets in
driver tx rings after the socket is closed (e.g. from tcpdrop).
In order for m_free to work reliably, add a new CSUM_SND_TAG flag in
csum_flags to indicate 'snd_tag' is set (rather than 'rcvif').
Drivers now also check this flag instead of checking snd_tag against
NULL. This avoids false positive matches when a forwarded packet
has a non-NULL rcvif that was treated as a send tag.
- cxgbe was relying on snd_tag_free being called when the inp was
detached so that it could kick the firmware to flush any pending
work on the flow. This is because the driver doesn't require ACK
messages from the firmware for every request, but instead does a
kind of manual interrupt coalescing by only setting a flag to
request a completion on a subset of requests. If all of the
in-flight requests don't have the flag when the tag is detached from
the inp, the flow might never return the credits. The current
snd_tag_free command issues a flush command to force the credits to
return. However, the credit return is what also frees the mbufs,
and since those mbufs now hold references on the tag, this meant
that snd_tag_free would never be called.
To fix, explicitly drop the mbuf's reference on the snd tag when the
mbuf is queued in the firmware work queue. This means that once the
inp's reference on the tag goes away and all in-flight mbufs have
been queued to the firmware, tag's refcount will drop to zero and
snd_tag_free will kick in and send the flush request. Note that we
need to avoid doing this in the middle of ethofld_tx(), so the
driver grabs a temporary reference on the tag around that loop to
defer the free to the end of the function in case it sends the last
mbuf to the queue after the inp has dropped its reference on the
tag.
- mlx5 preallocates send tags and was using the ifp pointer even when
the send tag wasn't in use. Explicitly use the ifp from other data
structures instead.
- Sprinkle some assertions in various places to assert that received
packets don't have a send tag, and that other places that overwrite
rcvif (e.g. 802.11 transmit) don't clobber a send tag pointer.
Reviewed by: gallatin, hselasky, rgrimes, ae
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20117
This allows replacing "sys/eventfilter.h" includes with "sys/_eventfilter.h"
in other header files (e.g., sys/{bus,conf,cpu}.h) and reduces header
pollution substantially.
EVENTHANDLER_DECLARE and EVENTHANDLER_LIST_DECLAREs were moved out of .c
files into appropriate headers (e.g., sys/proc.h, powernv/opal.h).
As a side effect of reduced header pollution, many .c files and headers no
longer contain needed definitions. The remainder of the patch addresses
adding appropriate includes to fix those files.
LOCK_DEBUG and LOCK_FILE_LINE_ARG are moved to sys/_lock.h, as required by
sys/mutex.h since r326106 (but silently protected by header pollution prior
to this change).
No functional change (intended). Of course, any out of tree modules that
relied on header pollution for sys/eventhandler.h, sys/lock.h, or
sys/mutex.h inclusion need to be fixed. __FreeBSD_version has been bumped.
Currently such routes are added with a link-level IFA, which is
plain wrong. Only after the insertion they get fixed by the special
link_rtrequest() ifa handler. This behaviour complicates routing code
and makes ifa selection more complex.
Streamline this process by explicitly moving link_rtrequest() logic
to the pre-insertion rt_getifa_fib() ifa selector. Avoid calling all
this logic in the loopback route case by explicitly specifying
proper rt_ifa inside the ifa_maintain_loopback_route().§
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20076
This commit adds new if_alloc_domain() and if_alloc_dev() methods to
allocate ifnets. When called with a domain on a NUMA machine,
ifalloc_domain() will record the NUMA domain in the ifnet, and it will
allocate the ifnet struct from memory which is local to that NUMA
node. Similarly, if_alloc_dev() is a wrapper for if_alloc_domain
which uses a driver supplied device_t to call ifalloc_domain() with
the appropriate domain.
Note that the new if_numa_domain field fits in an alignment pad in
struct ifnet, and so does not alter the size of the structure.
Reviewed by: glebius, kib, markj
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D19930
This is more compatible with formatting tools and looks more normal.
Reported by: jhb (on a different review)
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D18442
- Remove macros that covertly create epoch_tracker on thread stack. Such
macros a quite unsafe, e.g. will produce a buggy code if same macro is
used in embedded scopes. Explicitly declare epoch_tracker always.
- Unmask interface list IFNET_RLOCK_NOSLEEP(), interface address list
IF_ADDR_RLOCK() and interface AF specific data IF_AFDATA_RLOCK() read
locking macros to what they actually are - the net_epoch.
Keeping them as is is very misleading. They all are named FOO_RLOCK(),
while they no longer have lock semantics. Now they allow recursion and
what's more important they now no longer guarantee protection against
their companion WLOCK macros.
Note: INP_HASH_RLOCK() has same problems, but not touched by this commit.
This is non functional mechanical change. The only functionally changed
functions are ni6_addrs() and ni6_store_addrs(), where we no longer enter
epoch recursively.
Discussed with: jtl, gallatin
IFNET_RLOCK_NOSLEEP() is epoch_enter_preempt() in FreeBSD 12+. Holding
it in sysctl_rtsock() doesn't protect us from ifnet unlinking, because
unlinking occurs with IFNET_WLOCK(), that is rw_wlock+sx_xlock, and it
doesn check that concurrent code is running in epoch section. But while
we are in epoch section, we should be able to do access to ifnet's
fields, even it was unlinked. Thus do not change if_addr and if_hw_addr
fields in ifnet_detach_internal() to NULL, since rtsock code can do
access to these fields and this is allowed while it is running in epoch
section.
This should fix the race, when ifnet_detach_internal() unlinks ifnet
after we checked it for IFF_DYING in sysctl_dumpentry.
Move free(ifp->if_hw_addr) into ifnet_free_internal(). Also remove the
NULL check for ifp->if_description, since free(9) can correctly handle
NULL pointer.
MFC after: 1 week
The panic can happen, when some application does dump of routing table
using sysctl interface. To prevent this, set IFF_DYING flag in
if_detach_internal() function, when ifnet under lock is removed from
the chain. In sysctl_rtsock() take IFNET_RLOCK_NOSLEEP() to prevent
ifnet detach during routes enumeration. In case, if some interface was
detached in the time before we take the lock, add the check, that ifnet
is not DYING. This prevents access to memory that could be freed after
ifnet is unlinked.
PR: 227720, 230498, 233306
Reviewed by: bz, eugen
MFC after: 1 week
Sponsored by: Yandex LLC
Differential Revision: https://reviews.freebsd.org/D18338
mutexes but now are converted to epoch(9) use thread-private epoch_tracker.
Embedding tracker into ifnet(9) or ifnet derived structures creates a non
reentrable function, that will fail miserably if called simultaneously from
two different contexts.
A thread private tracker will provide a single tracker that would allow to
call these functions safely. It doesn't allow nested call, but this is not
expected from compatibility KPIs.
Reviewed by: markj
pf subscribes to ifnet_departure_event events, so it can clean up the
ifg_pf_kif and if_pf_kif pointers in the ifnet.
During vnet shutdown interfaces could go away without sending the event,
so pf ends up cleaning these up as part of its shutdown sequence, which
happens after the ifnet has already been freed.
Send the ifnet_departure_event during vnet shutdown, allowing pf to
clean up correctly.
MFC after: 2 weeks
Sponsored by: Orange Business Services
Differential Revision: https://reviews.freebsd.org/D17500
SX-locks, during if_purgeaddrs(), by not allowing to hold the epoch
read lock over typical network IOCTL code paths. This is a regression
issue after r334305.
Reviewed by: ae (network)
Differential revision: https://reviews.freebsd.org/D17647
MFC after: 1 week
Sponsored by: Mellanox Technologies
appearing and disappearing on the host system.
Such handling is need, because tunneling interfaces must use addresses,
that are configured on the host as ingress addresses for tunnels.
Otherwise the system can send spoofed packets with source address, that
belongs to foreign host.
The KPI uses ifaddr_event_ext event to implement addresses tracking.
Tunneling interfaces register event handlers and then they are
notified by the kernel, when an address disappears or appears.
ifaddr_event_compat() handler from if.c replaced by srcaddr_change_event()
in the ip_encap.c
MFC after: 1 month
Sponsored by: Yandex LLC
Differential Revision: https://reviews.freebsd.org/D17134
handler receives the type of event IFADDR_EVENT_ADD/IFADDR_EVENT_DEL,
and the pointer to ifaddr. Also ifaddr_event now is implemented using
ifaddr_event_ext handler.
MFC after: 3 weeks
Sponsored by: Yandex LLC
Differential Revision: https://reviews.freebsd.org/D17100
is done via using ifconfig, which uses a SIOCSIFMTU ioctl() command, or
doing it using a TUNSIFINFO/TAPSIFINFO ioctl() command.
Without this patch, for IPv6 the new MTU is not used when creating routes.
Especially, when initiating TCP connections after increasing the MTU,
the old MTU is still used to compute the MSS.
Thanks to ae@ and bz@ for helping to improve the patch.
Reviewed by: ae@, bz@
Approved by: re (kib@)
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D17180
toe_l2_resolve to fill up the complete vtag and not just the vid.
Reviewed by: kib@
MFC after: 1 week
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D16752
This is actually several different bugs:
- The code is not designed to handle inpcb deletion after interface deletion
- add reference for inpcb membership
- The multicast address has to be removed from interface lists when the refcount
goes to zero OR when the interface goes away
- decouple list disconnect from refcount (v6 only for now)
- ifmultiaddr can exist past being on interface lists
- add flag for tracking whether or not it's enqueued
- deferring freeing moptions makes the incpb cleanup code simpler but opens the
door wider still to races
- call inp_gcmoptions synchronously after dropping the the inpcb lock
Fundamentally multicast needs a rewrite - but keep applying band-aids for now.
Tested by: kp
Reported by: novel, kp, lwhsu
Add generic function if_tunnel_check_nesting() that does check for
allowed nesting level for tunneling interfaces and also does loop
detection. Use it in gif(4), gre(4) and me(4) interfaces.
Differential Revision: https://reviews.freebsd.org/D16162
ifioctl(). Move it inside the proper #ifdef. This was throwing a valid
"Assigned but unused" warning with gcc.
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D16063
- Add tracker argument to preemptible epochs
- Inline epoch read path in kernel and tied modules
- Change in_epoch to take an epoch as argument
- Simplify tfb_tcp_do_segment to not take a ti_locked argument,
there's no longer any benefit to dropping the pcbinfo lock
and trying to do so just adds an error prone branchfest to
these functions
- Remove cases of same function recursion on the epoch as
recursing is no longer free.
- Remove the the TAILQ_ENTRY and epoch_section from struct
thread as the tracker field is now stack or heap allocated
as appropriate.
Tested by: pho and Limelight Networks
Reviewed by: kbowling at llnw dot com
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D16066
There are risks associated with waiting on a preemptible epoch section.
Change the name to make them not be the default and document the issue
under CAVEATS.
Reported by: markj
adds:
- epoch_enter_critical() - can be called inside a different epoch,
starts a section that will acquire any MTX_DEF mutexes or do
anything that might sleep.
- epoch_exit_critical() - corresponding exit call
- epoch_wait_critical() - wait variant that is guaranteed that any
threads in a section are running.
- epoch_global_critical - an epoch_wait_critical safe epoch instance
Requested by: markj
Approved by: sbruno
if_bridge has a lot of limitations that make it scale poorly to higher data
rates. In my projects/VPC branch I leverage the bridge interface between
layers for my high speed soft switch as well as for purposes of stacking
in general.
Reviewed by: sbruno@
Approved by: sbruno@
Differential Revision: https://reviews.freebsd.org/D15344
Make if_printf() use vlog() instead of vprintf(). This means it can no
longer return the number of characters printed, as it used to, but every
single call to if_printf() in the entire kernel ignores the return value
anyway; just return 0 so we don't have to change the prototype.
Consistently use if_printf() throughout sys/net/if.c, instead of a
mixture of if_printf() and log().
In ifa_maintain_loopback_route(), don't needlessly log an error if we
either failed to add a route because it already existed or failed to
remove one because it did not. We still return an error code, though.
MFC after: 1 week
