| Age | Commit message (Collapse) | Author |
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When budget is non-zero, skb_unref() has already handled the
NULL checking.
When budget is zero, the dev_consume_skb_any() has handled NULL
checking in __dev_kfree_skb_irq(), or dev_kfree_skb() which also
ultimately call skb_unref().
So remove the unnecessary checking in napi_consume_skb().
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Pass the region to be snapshotted to the function performing the
snapshot. This allows one function to operate on numerous regions.
v4:
Add missing kerneldoc for ICE
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Drop repeated words in net/core/.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The dev flash status notify function parameter lists are getting
rather long, so add a struct to be filled and passed rather than
continuously changing the function signatures.
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add a timeout element to the DEVLINK_CMD_FLASH_UPDATE_STATUS
netlink message for use by a userland utility to show that
a particular firmware flash activity may take a long but
bounded time to finish. Also add a handy helper for drivers
to make use of the new timeout value.
UI usage hints:
- if non-zero, add timeout display to the end of the status line
[component] status_msg ( Xm Ys : Am Bs )
using the timeout value for Am Bs and updating the Xm Ys
every second
- if the timeout expires while awaiting the next update,
display something like
[component] status_msg ( timeout reached : Am Bs )
- if new status notify messages are received, remove
the timeout and start over
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The combination of aca_free_rcu, introduced in commit 2384d02520ff
("net/ipv6: Add anycast addresses to a global hashtable"), and
fib6_info_destroy_rcu, introduced in commit 9b0a8da8c4c6 ("net/ipv6:
respect rcu grace period before freeing fib6_info"), can result in
an extra rcu grace period being needed when deleting an interface,
with the result that netdev_wait_allrefs ends up hitting the msleep(250),
which is considerably longer than the required grace period.
This can result in long delays when deleting a large number of interfaces,
and it can be observed with this script:
ns=dummy-ns
NIFS=100
ip netns add $ns
ip netns exec $ns ip link set lo up
ip netns exec $ns sysctl net.ipv6.conf.default.disable_ipv6=0
ip netns exec $ns sysctl net.ipv6.conf.default.forwarding=1
for ((i=0; i<$NIFS; i++))
do
if=eth$i
ip netns exec $ns ip link add $if type dummy
ip netns exec $ns ip link set $if up
ip netns exec $ns ip -6 addr add 2021:$i::1/120 dev $if
done
for ((i=0; i<$NIFS; i++))
do
if=eth$i
ip netns exec $ns ip link del $if
done
ip netns del $ns
Instead of using a fixed msleep(250), this patch tries an extra
rcu_barrier() followed by an exponential backoff.
Time with this patch on a 5.4 kernel:
real 0m7.704s
user 0m0.385s
sys 0m1.230s
Time without this patch:
real 0m31.522s
user 0m0.438s
sys 0m1.156s
v2: use exponential backoff instead of trying to wake up
netdev_wait_allrefs.
v3: preserve reverse christmas tree ordering of local variables
v4: try an extra rcu_barrier before the backoff, plus some
cosmetic changes.
Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Alexei Starovoitov says:
====================
pull-request: bpf 2020-09-15
The following pull-request contains BPF updates for your *net* tree.
We've added 12 non-merge commits during the last 19 day(s) which contain
a total of 10 files changed, 47 insertions(+), 38 deletions(-).
The main changes are:
1) docs/bpf fixes, from Andrii.
2) ld_abs fix, from Daniel.
3) socket casting helpers fix, from Martin.
4) hash iterator fixes, from Yonghong.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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To support modifying the used_maps array, we use a mutex to protect
the use of the counter and the array. The mutex is initialized right
after the prog aux is allocated, and destroyed right before prog
aux is freed. This way we guarantee it's initialized for both cBPF
and eBPF.
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Link: https://lore.kernel.org/bpf/20200915234543.3220146-2-sdf@google.com
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The bpf_skc_to_* type casting helpers are available to
BPF_PROG_TYPE_TRACING. The traced PTR_TO_BTF_ID may be NULL.
For example, the skb->sk may be NULL. Thus, these casting helpers
need to check "!sk" also and this patch fixes them.
Fixes: 0d4fad3e57df ("bpf: Add bpf_skc_to_udp6_sock() helper")
Fixes: 478cfbdf5f13 ("bpf: Add bpf_skc_to_{tcp, tcp_timewait, tcp_request}_sock() helpers")
Fixes: af7ec1383361 ("bpf: Add bpf_skc_to_tcp6_sock() helper")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200915182959.241101-1-kafai@fb.com
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Introduce a test command for health reporters. User might use this
command to trigger test event on a reporter if the reporter supports it.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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A DSA master interface has upper network devices, each representing an
Ethernet switch port attached to it. Demultiplexing the source ports and
setting skb->dev accordingly is done through the catch-all ETH_P_XDSA
packet_type handler. Catch-all because DSA vendors have various header
implementations, which can be placed anywhere in the frame: before the
DMAC, before the EtherType, before the FCS, etc. So, the ETH_P_XDSA
handler acts like an rx_handler more than anything.
It is unlikely for the DSA master interface to have any other upper than
the DSA switch interfaces themselves. Only maybe a bridge upper*, but it
is very likely that the DSA master will have no 8021q upper. So
__netif_receive_skb_core() will try to untag the VLAN, despite the fact
that the DSA switch interface might have an 8021q upper. So the skb will
never reach that.
So far, this hasn't been a problem because most of the possible
placements of the DSA switch header mentioned in the first paragraph
will displace the VLAN header when the DSA master receives the frame, so
__netif_receive_skb_core() will not actually execute any VLAN-specific
code for it. This only becomes a problem when the DSA switch header does
not displace the VLAN header (for example with a tail tag).
What the patch does is it bypasses the untagging of the skb when there
is a DSA switch attached to this net device. So, DSA is the only
packet_type handler which requires seeing the VLAN header. Once skb->dev
will be changed, __netif_receive_skb_core() will be invoked again and
untagging, or delivery to an 8021q upper, will happen in the RX of the
DSA switch interface itself.
*see commit 9eb8eff0cf2f ("net: bridge: allow enslaving some DSA master
network devices". This is actually the reason why I prefer keeping DSA
as a packet_type handler of ETH_P_XDSA rather than converting to an
rx_handler. Currently the rx_handler code doesn't support chaining, and
this is a problem because a DSA master might be bridged.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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flowi4_multipath_hash was added by the commit referenced below for
tunnels. Unfortunately, the patch did not initialize the new field
for several fast path lookups that do not initialize the entire flow
struct to 0. Fix those locations. Currently, flowi4_multipath_hash
is random garbage and affects the hash value computed by
fib_multipath_hash for multipath selection.
Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash")
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
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flush_all_backlogs() may cause deadlock on systems
running processes with FIFO scheduling policy.
The above is critical in -RT scenarios, where user-space
specifically ensure no network activity is scheduled on
the CPU running the mentioned FIFO process, but still get
stuck.
This commit tries to address the problem checking the
backlog status on the remote CPUs before scheduling the
flush operation. If the backlog is empty, we can skip it.
v1 -> v2:
- explicitly clear flushed cpu mask - Eric
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Now that the previous patches have removed the code that uses the
flags argument to _bpf_setsockopt(), we can remove that argument.
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Kevin Yang <yyd@google.com>
Cc: Lawrence Brakmo <brakmo@fb.com>
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Now that the previous patches ensure that all call sites for
tcp_set_congestion_control() want to initialize congestion control, we
can simplify tcp_set_congestion_control() by removing the reinit
argument and the code to support it.
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Kevin Yang <yyd@google.com>
Cc: Lawrence Brakmo <brakmo@fb.com>
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Now that the previous patch ensures we don't initialize the congestion
control twice, when EBPF sets the congestion control algorithm at
connection establishment we can simplify the code by simply
initializing the congestion control module at that time.
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Kevin Yang <yyd@google.com>
Cc: Lawrence Brakmo <brakmo@fb.com>
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When a netdev is enslaved to a bridge, its parent identifier is queried.
This is done so that packets that were already forwarded in hardware
will not be forwarded again by the bridge device between netdevs
belonging to the same hardware instance.
The operation fails when the netdev is an upper of netdevs with
different parent identifiers.
Instead of failing the enslavement, have dev_get_port_parent_id() return
'-EOPNOTSUPP' which will signal the bridge to skip the query operation.
Other callers of the function are not affected by this change.
Fixes: 7e1146e8c10c ("net: devlink: introduce devlink_compat_switch_id_get() helper")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reported-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Since commit 8d7017fd621d ("blackhole_netdev: use blackhole_netdev to
invalidate dst entries"), we use blackhole_netdev to invalidate dst entries
instead of loopback device anymore.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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netpoll needs to traverse dev->napi_list under RCU, make
sure it uses the right iterator and that removal from this
list is handled safely.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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To RCUify napi->dev_list we need to replace list_del_init()
with list_del_rcu(). There is no _init() version for RCU for
obvious reasons. Up until now netif_napi_del() was idempotent
so to make sure it remains such add a bit which is set when
NAPI is listed, and cleared when it removed. Since we don't
expect multiple calls to netif_napi_add() to be correct,
add a warning on that side.
Now that napi_hash_add / napi_hash_del are only called by
napi_add / del we can actually steal its bit. We just need
to make sure hash node is initialized correctly.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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We allow drivers to call napi_hash_del() before calling
netif_napi_del() to batch RCU grace periods. This makes
the API asymmetric and leaks internal implementation details.
Soon we will want the grace period to protect more than just
the NAPI hash table.
Restructure the API and have drivers call a new function -
__netif_napi_del() if they want to take care of RCU waits.
Note that only core was checking the return status from
napi_hash_del() so the new helper does not report if the
NAPI was actually deleted.
Some notes on driver oddness:
- veth observed the grace period before calling netif_napi_del()
but that should not matter
- myri10ge observed normal RCU flavor
- bnx2x and enic did not actually observe the grace period
(unless they did so implicitly)
- virtio_net and enic only unhashed Rx NAPIs
The last two points seem to indicate that the calls to
napi_hash_del() were a left over rather than an optimization.
Regardless, it's easy enough to correct them.
This patch may introduce extra synchronize_net() calls for
interfaces which set NAPI_STATE_NO_BUSY_POLL and depend on
free_netdev() to call netif_napi_del(). This seems inevitable
since we want to use RCU for netpoll dev->napi_list traversal,
and almost no drivers set IFF_DISABLE_NETPOLL.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Following change will add support for a corner case where
we may not have a netdev to pass to devlink_port_type_eth_set()
but we still want to set port type.
This is definitely a corner case, and drivers should not normally
pass NULL netdev - print a warning message when this happens.
Sadly for other port types (ib) switches don't have a device
reference, the way we always do for Ethernet, so we can't put
the warning in __devlink_port_type_set().
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add bpf_iter support for sockmap / sockhash, based on the bpf_sk_storage and
hashtable implementation. sockmap and sockhash share the same iteration
context: a pointer to an arbitrary key and a pointer to a socket. Both
pointers may be NULL, and so BPF has to perform a NULL check before accessing
them. Technically it's not possible for sockhash iteration to yield a NULL
socket, but we ignore this to be able to use a single iteration point.
Iteration will visit all keys that remain unmodified during the lifetime of
the iterator. It may or may not visit newly added ones.
Switch from using rcu_dereference_raw to plain rcu_dereference, so we gain
another guard rail if CONFIG_PROVE_RCU is enabled.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200909162712.221874-3-lmb@cloudflare.com
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The lookup paths for sockmap and sockhash currently include a check
that returns NULL if the socket we just found is not a full socket.
However, this check is not necessary. On insertion we ensure that
we have a full socket (caveat around sock_ops), so request sockets
are not a problem. Time-wait sockets are allocated separate from
the original socket and then fed into the hashdance. They don't
affect the sockets already stored in the sockmap.
Suggested-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200909162712.221874-2-lmb@cloudflare.com
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Remove duplicate headers which are included twice.
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200908132201.184005-1-chenzhou10@huawei.com
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Now that controller number attribute is available, use it when
building phsy_port_name for external controller ports.
An example devlink port and representor netdev name consist of controller
annotation for external controller with controller number = 1,
for a VF 1 of PF 0:
$ devlink port show pci/0000:06:00.0/2
pci/0000:06:00.0/2: type eth netdev ens2f0c1pf0vf1 flavour pcivf controller 1 pfnum 0 vfnum 1 external true splittable false
function:
hw_addr 00:00:00:00:00:00
$ devlink port show pci/0000:06:00.0/2 -jp
{
"port": {
"pci/0000:06:00.0/2": {
"type": "eth",
"netdev": "ens2f0c1pf0vf1",
"flavour": "pcivf",
"controller": 1,
"pfnum": 0,
"vfnum": 1,
"external": true,
"splittable": false,
"function": {
"hw_addr": "00:00:00:00:00:00"
}
}
}
}
Controller number annotation is skipped for non external controllers to
maintain backward compatibility.
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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A devlink port may be for a controller consist of PCI device.
A devlink instance holds ports of two types of controllers.
(1) controller discovered on same system where eswitch resides
This is the case where PCI PF/VF of a controller and devlink eswitch
instance both are located on a single system.
(2) controller located on external host system.
This is the case where a controller is located in one system and its
devlink eswitch ports are located in a different system.
When a devlink eswitch instance serves the devlink ports of both
controllers together, PCI PF/VF numbers may overlap.
Due to this a unique phys_port_name cannot be constructed.
For example in below such system controller-0 and controller-1, each has
PCI PF pf0 whose eswitch ports can be present in controller-0.
These results in phys_port_name as "pf0" for both.
Similar problem exists for VFs and upcoming Sub functions.
An example view of two controller systems:
---------------------------------------------------------
| |
| --------- --------- ------- ------- |
----------- | | vf(s) | | sf(s) | |vf(s)| |sf(s)| |
| server | | ------- ----/---- ---/----- ------- ---/--- ---/--- |
| pci rc |=== | pf0 |______/________/ | pf1 |___/_______/ |
| connect | | ------- ------- |
----------- | | controller_num=1 (no eswitch) |
------|--------------------------------------------------
(internal wire)
|
---------------------------------------------------------
| devlink eswitch ports and reps |
| ----------------------------------------------------- |
| |ctrl-0 | ctrl-0 | ctrl-0 | ctrl-0 | ctrl-0 |ctrl-0 | |
| |pf0 | pf0vfN | pf0sfN | pf1 | pf1vfN |pf1sfN | |
| ----------------------------------------------------- |
| |ctrl-1 | ctrl-1 | ctrl-1 | ctrl-1 | ctrl-1 |ctrl-1 | |
| |pf1 | pf1vfN | pf1sfN | pf1 | pf1vfN |pf0sfN | |
| ----------------------------------------------------- |
| |
| |
| --------- --------- ------- ------- |
| | vf(s) | | sf(s) | |vf(s)| |sf(s)| |
| ------- ----/---- ---/----- ------- ---/--- ---/--- |
| | pf0 |______/________/ | pf1 |___/_______/ |
| ------- ------- |
| |
| local controller_num=0 (eswitch) |
---------------------------------------------------------
An example devlink port for external controller with controller
number = 1 for a VF 1 of PF 0:
$ devlink port show pci/0000:06:00.0/2
pci/0000:06:00.0/2: type eth netdev ens2f0pf0vf1 flavour pcivf controller 1 pfnum 0 vfnum 1 external true splittable false
function:
hw_addr 00:00:00:00:00:00
$ devlink port show pci/0000:06:00.0/2 -jp
{
"port": {
"pci/0000:06:00.0/2": {
"type": "eth",
"netdev": "ens2f0pf0vf1",
"flavour": "pcivf",
"controller": 1,
"pfnum": 0,
"vfnum": 1,
"external": true,
"splittable": false,
"function": {
"hw_addr": "00:00:00:00:00:00"
}
}
}
}
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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A devlink eswitch port may represent PCI PF/VF ports of a controller.
A controller either located on same system or it can be an external
controller located in host where such NIC is plugged in.
Add the ability for driver to specify if a port is for external
controller.
Use such flag in the mlx5_core driver.
An example of an external controller having VF1 of PF0 belong to
controller 1.
$ devlink port show pci/0000:06:00.0/2
pci/0000:06:00.0/2: type eth netdev ens2f0pf0vf1 flavour pcivf pfnum 0 vfnum 1 external true splittable false
function:
hw_addr 00:00:00:00:00:00
$ devlink port show pci/0000:06:00.0/2 -jp
{
"port": {
"pci/0000:06:00.0/2": {
"type": "eth",
"netdev": "ens2f0pf0vf1",
"flavour": "pcivf",
"pfnum": 0,
"vfnum": 1,
"external": true,
"splittable": false,
"function": {
"hw_addr": "00:00:00:00:00:00"
}
}
}
}
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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If CONFIG_IPV6=m, the IPV6 functions won't be found by the linker:
ld: net/core/fib_rules.o: in function `fib_rules_lookup':
fib_rules.c:(.text+0x606): undefined reference to `fib6_rule_match'
ld: fib_rules.c:(.text+0x611): undefined reference to `fib6_rule_match'
ld: fib_rules.c:(.text+0x68c): undefined reference to `fib6_rule_action'
ld: fib_rules.c:(.text+0x693): undefined reference to `fib6_rule_action'
ld: fib_rules.c:(.text+0x6aa): undefined reference to `fib6_rule_suppress'
ld: fib_rules.c:(.text+0x6bc): undefined reference to `fib6_rule_suppress'
make: *** [Makefile:1166: vmlinux] Error 1
Reported-by: Sven Joachim <svenjoac@gmx.de>
Fixes: b9aaec8f0be5 ("fib: use indirect call wrappers in the most common fib_rules_ops")
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Bryce reported that he saw the following with:
0: r6 = r1
1: r1 = 12
2: r0 = *(u16 *)skb[r1]
The xlated sequence was incorrectly clobbering r2 with pointer
value of r6 ...
0: (bf) r6 = r1
1: (b7) r1 = 12
2: (bf) r1 = r6
3: (bf) r2 = r1
4: (85) call bpf_skb_load_helper_16_no_cache#7692160
... and hence call to the load helper never succeeded given the
offset was too high. Fix it by reordering the load of r6 to r1.
Other than that the insn has similar calling convention than BPF
helpers, that is, r0 - r5 are scratch regs, so nothing else
affected after the insn.
Fixes: e0cea7ce988c ("bpf: implement ld_abs/ld_ind in native bpf")
Reported-by: Bryce Kahle <bryce.kahle@datadoghq.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/cace836e4d07bb63b1a53e49c5dfb238a040c298.1599512096.git.daniel@iogearbox.net
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This reverts commit 8d7e5dee972f1cde2ba96c621f1541fa36e7d4f4.
To protect netns id, the nsid_lock is used when netns id is being
allocated and removed by peernet2id_alloc() and unhash_nsid().
The nsid_lock can be used in BH context but only spin_lock() is used
in this code.
Using spin_lock() instead of spin_lock_bh() can result in a deadlock in
the following scenario reported by the lockdep.
In order to avoid a deadlock, the spin_lock_bh() should be used instead
of spin_lock() to acquire nsid_lock.
Test commands:
ip netns del nst
ip netns add nst
ip link add veth1 type veth peer name veth2
ip link set veth1 netns nst
ip netns exec nst ip link add name br1 type bridge vlan_filtering 1
ip netns exec nst ip link set dev br1 up
ip netns exec nst ip link set dev veth1 master br1
ip netns exec nst ip link set dev veth1 up
ip netns exec nst ip link add macvlan0 link br1 up type macvlan
Splat looks like:
[ 33.615860][ T607] WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
[ 33.617194][ T607] 5.9.0-rc1+ #665 Not tainted
[ ... ]
[ 33.670615][ T607] Chain exists of:
[ 33.670615][ T607] &mc->mca_lock --> &bridge_netdev_addr_lock_key --> &net->nsid_lock
[ 33.670615][ T607]
[ 33.673118][ T607] Possible interrupt unsafe locking scenario:
[ 33.673118][ T607]
[ 33.674599][ T607] CPU0 CPU1
[ 33.675557][ T607] ---- ----
[ 33.676516][ T607] lock(&net->nsid_lock);
[ 33.677306][ T607] local_irq_disable();
[ 33.678517][ T607] lock(&mc->mca_lock);
[ 33.679725][ T607] lock(&bridge_netdev_addr_lock_key);
[ 33.681166][ T607] <Interrupt>
[ 33.681791][ T607] lock(&mc->mca_lock);
[ 33.682579][ T607]
[ 33.682579][ T607] *** DEADLOCK ***
[ ... ]
[ 33.922046][ T607] stack backtrace:
[ 33.922999][ T607] CPU: 3 PID: 607 Comm: ip Not tainted 5.9.0-rc1+ #665
[ 33.924099][ T607] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[ 33.925714][ T607] Call Trace:
[ 33.926238][ T607] dump_stack+0x78/0xab
[ 33.926905][ T607] check_irq_usage+0x70b/0x720
[ 33.927708][ T607] ? iterate_chain_key+0x60/0x60
[ 33.928507][ T607] ? check_path+0x22/0x40
[ 33.929201][ T607] ? check_noncircular+0xcf/0x180
[ 33.930024][ T607] ? __lock_acquire+0x1952/0x1f20
[ 33.930860][ T607] __lock_acquire+0x1952/0x1f20
[ 33.931667][ T607] lock_acquire+0xaf/0x3a0
[ 33.932366][ T607] ? peernet2id_alloc+0x3a/0x170
[ 33.933147][ T607] ? br_port_fill_attrs+0x54c/0x6b0 [bridge]
[ 33.934140][ T607] ? br_port_fill_attrs+0x5de/0x6b0 [bridge]
[ 33.935113][ T607] ? kvm_sched_clock_read+0x14/0x30
[ 33.935974][ T607] _raw_spin_lock+0x30/0x70
[ 33.936728][ T607] ? peernet2id_alloc+0x3a/0x170
[ 33.937523][ T607] peernet2id_alloc+0x3a/0x170
[ 33.938313][ T607] rtnl_fill_ifinfo+0xb5e/0x1400
[ 33.939091][ T607] rtmsg_ifinfo_build_skb+0x8a/0xf0
[ 33.939953][ T607] rtmsg_ifinfo_event.part.39+0x17/0x50
[ 33.940863][ T607] rtmsg_ifinfo+0x1f/0x30
[ 33.941571][ T607] __dev_notify_flags+0xa5/0xf0
[ 33.942376][ T607] ? __irq_work_queue_local+0x49/0x50
[ 33.943249][ T607] ? irq_work_queue+0x1d/0x30
[ 33.943993][ T607] ? __dev_set_promiscuity+0x7b/0x1a0
[ 33.944878][ T607] __dev_set_promiscuity+0x7b/0x1a0
[ 33.945758][ T607] dev_set_promiscuity+0x1e/0x50
[ 33.946582][ T607] br_port_set_promisc+0x1f/0x40 [bridge]
[ 33.947487][ T607] br_manage_promisc+0x8b/0xe0 [bridge]
[ 33.948388][ T607] __dev_set_promiscuity+0x123/0x1a0
[ 33.949244][ T607] __dev_set_rx_mode+0x68/0x90
[ 33.950021][ T607] dev_uc_add+0x50/0x60
[ 33.950720][ T607] macvlan_open+0x18e/0x1f0 [macvlan]
[ 33.951601][ T607] __dev_open+0xd6/0x170
[ 33.952269][ T607] __dev_change_flags+0x181/0x1d0
[ 33.953056][ T607] rtnl_configure_link+0x2f/0xa0
[ 33.953884][ T607] __rtnl_newlink+0x6b9/0x8e0
[ 33.954665][ T607] ? __lock_acquire+0x95d/0x1f20
[ 33.955450][ T607] ? lock_acquire+0xaf/0x3a0
[ 33.956193][ T607] ? is_bpf_text_address+0x5/0xe0
[ 33.956999][ T607] rtnl_newlink+0x47/0x70
Acked-by: Guillaume Nault <gnault@redhat.com>
Fixes: 8d7e5dee972f ("netns: don't disable BHs when locking "nsid_lock"")
Reported-by: syzbot+3f960c64a104eaa2c813@syzkaller.appspotmail.com
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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We got slightly different patches removing a double word
in a comment in net/ipv4/raw.c - picked the version from net.
Simple conflict in drivers/net/ethernet/ibm/ibmvnic.c. Use cached
values instead of VNIC login response buffer (following what
commit 507ebe6444a4 ("ibmvnic: Fix use-after-free of VNIC login
response buffer") did).
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Pull networking fixes from David Miller:
1) Use netif_rx_ni() when necessary in batman-adv stack, from Jussi
Kivilinna.
2) Fix loss of RTT samples in rxrpc, from David Howells.
3) Memory leak in hns_nic_dev_probe(), from Dignhao Liu.
4) ravb module cannot be unloaded, fix from Yuusuke Ashizuka.
5) We disable BH for too lokng in sctp_get_port_local(), add a
cond_resched() here as well, from Xin Long.
6) Fix memory leak in st95hf_in_send_cmd, from Dinghao Liu.
7) Out of bound access in bpf_raw_tp_link_fill_link_info(), from
Yonghong Song.
8) Missing of_node_put() in mt7530 DSA driver, from Sumera
Priyadarsini.
9) Fix crash in bnxt_fw_reset_task(), from Michael Chan.
10) Fix geneve tunnel checksumming bug in hns3, from Yi Li.
11) Memory leak in rxkad_verify_response, from Dinghao Liu.
12) In tipc, don't use smp_processor_id() in preemptible context. From
Tuong Lien.
13) Fix signedness issue in mlx4 memory allocation, from Shung-Hsi Yu.
14) Missing clk_disable_prepare() in gemini driver, from Dan Carpenter.
15) Fix ABI mismatch between driver and firmware in nfp, from Louis
Peens.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (110 commits)
net/smc: fix sock refcounting in case of termination
net/smc: reset sndbuf_desc if freed
net/smc: set rx_off for SMCR explicitly
net/smc: fix toleration of fake add_link messages
tg3: Fix soft lockup when tg3_reset_task() fails.
doc: net: dsa: Fix typo in config code sample
net: dp83867: Fix WoL SecureOn password
nfp: flower: fix ABI mismatch between driver and firmware
tipc: fix shutdown() of connectionless socket
ipv6: Fix sysctl max for fib_multipath_hash_policy
drivers/net/wan/hdlc: Change the default of hard_header_len to 0
net: gemini: Fix another missing clk_disable_unprepare() in probe
net: bcmgenet: fix mask check in bcmgenet_validate_flow()
amd-xgbe: Add support for new port mode
net: usb: dm9601: Add USB ID of Keenetic Plus DSL
vhost: fix typo in error message
net: ethernet: mlx4: Fix memory allocation in mlx4_buddy_init()
pktgen: fix error message with wrong function name
net: ethernet: ti: am65-cpsw: fix rmii 100Mbit link mode
cxgb4: fix thermal zone device registration
...
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Daniel Borkmann says:
====================
pull-request: bpf-next 2020-09-01
The following pull-request contains BPF updates for your *net-next* tree.
There are two small conflicts when pulling, resolve as follows:
1) Merge conflict in tools/lib/bpf/libbpf.c between 88a82120282b ("libbpf: Factor
out common ELF operations and improve logging") in bpf-next and 1e891e513e16
("libbpf: Fix map index used in error message") in net-next. Resolve by taking
the hunk in bpf-next:
[...]
scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx);
data = elf_sec_data(obj, scn);
if (!scn || !data) {
pr_warn("elf: failed to get %s map definitions for %s\n",
MAPS_ELF_SEC, obj->path);
return -EINVAL;
}
[...]
2) Merge conflict in drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c between
9647c57b11e5 ("xsk: i40e: ice: ixgbe: mlx5: Test for dma_need_sync earlier for
better performance") in bpf-next and e20f0dbf204f ("net/mlx5e: RX, Add a prefetch
command for small L1_CACHE_BYTES") in net-next. Resolve the two locations by retaining
net_prefetch() and taking xsk_buff_dma_sync_for_cpu() from bpf-next. Should look like:
[...]
xdp_set_data_meta_invalid(xdp);
xsk_buff_dma_sync_for_cpu(xdp, rq->xsk_pool);
net_prefetch(xdp->data);
[...]
We've added 133 non-merge commits during the last 14 day(s) which contain
a total of 246 files changed, 13832 insertions(+), 3105 deletions(-).
The main changes are:
1) Initial support for sleepable BPF programs along with bpf_copy_from_user() helper
for tracing to reliably access user memory, from Alexei Starovoitov.
2) Add BPF infra for writing and parsing TCP header options, from Martin KaFai Lau.
3) bpf_d_path() helper for returning full path for given 'struct path', from Jiri Olsa.
4) AF_XDP support for shared umems between devices and queues, from Magnus Karlsson.
5) Initial prep work for full BPF-to-BPF call support in libbpf, from Andrii Nakryiko.
6) Generalize bpf_sk_storage map & add local storage for inodes, from KP Singh.
7) Implement sockmap/hash updates from BPF context, from Lorenz Bauer.
8) BPF xor verification for scalar types & add BPF link iterator, from Yonghong Song.
9) Use target's prog type for BPF_PROG_TYPE_EXT prog verification, from Udip Pant.
10) Rework BPF tracing samples to use libbpf loader, from Daniel T. Lee.
11) Fix xdpsock sample to really cycle through all buffers, from Weqaar Janjua.
12) Improve type safety for tun/veth XDP frame handling, from Maciej Żenczykowski.
13) Various smaller cleanups and improvements all over the place.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Error on calling kthread_create_on_node prints wrong function name,
kernel_thread.
Fixes: 94dcf29a11b3 ("kthread: use kthread_create_on_node()")
Signed-off-by: Leesoo Ahn <dev@ooseel.net>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The sysctl that was added earlier by commit 79134e6ce2c ("net: do
not create fallback tunnels for non-default namespaces") to create
fall-back only in root-ns. This patch enhances that behavior to provide
option not to create fallback tunnels in root-ns as well. Since modules
that create fallback tunnels could be built-in and setting the sysctl
value after booting is pointless, so added a kernel cmdline options to
change this default. The default setting is preseved for backward
compatibility. The kernel command line option of fb_tunnels=initns will
set the sysctl value to 1 and will create fallback tunnels only in initns
while kernel cmdline fb_tunnels=none will set the sysctl value to 2 and
fallback tunnels are skipped in every netns.
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Maciej Zenczykowski <maze@google.com>
Cc: Jian Yang <jianyang@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Some properties of the inner map is used in the verification time.
When an inner map is inserted to an outer map at runtime,
bpf_map_meta_equal() is currently used to ensure those properties
of the inserting inner map stays the same as the verification
time.
In particular, the current bpf_map_meta_equal() checks max_entries which
turns out to be too restrictive for most of the maps which do not use
max_entries during the verification time. It limits the use case that
wants to replace a smaller inner map with a larger inner map. There are
some maps do use max_entries during verification though. For example,
the map_gen_lookup in array_map_ops uses the max_entries to generate
the inline lookup code.
To accommodate differences between maps, the map_meta_equal is added
to bpf_map_ops. Each map-type can decide what to check when its
map is used as an inner map during runtime.
Also, some map types cannot be used as an inner map and they are
currently black listed in bpf_map_meta_alloc() in map_in_map.c.
It is not unusual that the new map types may not aware that such
blacklist exists. This patch enforces an explicit opt-in
and only allows a map to be used as an inner map if it has
implemented the map_meta_equal ops. It is based on the
discussion in [1].
All maps that support inner map has its map_meta_equal points
to bpf_map_meta_equal in this patch. A later patch will
relax the max_entries check for most maps. bpf_types.h
counts 28 map types. This patch adds 23 ".map_meta_equal"
by using coccinelle. -5 for
BPF_MAP_TYPE_PROG_ARRAY
BPF_MAP_TYPE_(PERCPU)_CGROUP_STORAGE
BPF_MAP_TYPE_STRUCT_OPS
BPF_MAP_TYPE_ARRAY_OF_MAPS
BPF_MAP_TYPE_HASH_OF_MAPS
The "if (inner_map->inner_map_meta)" check in bpf_map_meta_alloc()
is moved such that the same error is returned.
[1]: https://lore.kernel.org/bpf/20200522022342.899756-1-kafai@fb.com/
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200828011806.1970400-1-kafai@fb.com
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Fix some comments, including wrong function name, duplicated word and so
on.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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napi_disable() makes sure to set the NAPI_STATE_NPSVC bit to prevent
netpoll from accessing rings before init is complete. However, the
same is not done for fresh napi instances in netif_napi_add(),
even though we expect NAPI instances to be added as disabled.
This causes crashes during driver reconfiguration (enabling XDP,
changing the channel count) - if there is any printk() after
netif_napi_add() but before napi_enable().
To ensure memory ordering is correct we need to use RCU accessors.
Reported-by: Rob Sherwood <rsher@fb.com>
Fixes: 2d8bff12699a ("netpoll: Close race condition between poll_one_napi and napi_disable")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Adds support for both bpf_{sk, inode}_storage_{get, delete} to be used
in LSM programs. These helpers are not used for tracing programs
(currently) as their usage is tied to the life-cycle of the object and
should only be used where the owning object won't be freed (when the
owning object is passed as an argument to the LSM hook). Thus, they
are safer to use in LSM hooks than tracing. Usage of local storage in
tracing programs will probably follow a per function based whitelist
approach.
Since the UAPI helper signature for bpf_sk_storage expect a bpf_sock,
it, leads to a compilation warning for LSM programs, it's also updated
to accept a void * pointer instead.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-7-kpsingh@chromium.org
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A purely mechanical change:
bpf_sk_storage.c = bpf_sk_storage.c + bpf_local_storage.c
bpf_sk_storage.h = bpf_sk_storage.h + bpf_local_storage.h
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-5-kpsingh@chromium.org
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Refactor the functionality in bpf_sk_storage.c so that concept of
storage linked to kernel objects can be extended to other objects like
inode, task_struct etc.
Each new local storage will still be a separate map and provide its own
set of helpers. This allows for future object specific extensions and
still share a lot of the underlying implementation.
This includes the changes suggested by Martin in:
https://lore.kernel.org/bpf/20200725013047.4006241-1-kafai@fb.com/
adding new map operations to support bpf_local_storage maps:
* storages for different kernel objects to optionally have different
memory charging strategy (map_local_storage_charge,
map_local_storage_uncharge)
* Functionality to extract the storage pointer from a pointer to the
owning object (map_owner_storage_ptr)
Co-developed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-4-kpsingh@chromium.org
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Provide the a ability to define local storage caches on a per-object
type basis. The caches and caching indices for different objects should
not be inter-mixed as suggested in:
https://lore.kernel.org/bpf/20200630193441.kdwnkestulg5erii@kafai-mbp.dhcp.thefacebook.com/
"Caching a sk-storage at idx=0 of a sk should not stop an
inode-storage to be cached at the same idx of a inode."
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-3-kpsingh@chromium.org
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A purely mechanical change to split the renaming from the actual
generalization.
Flags/consts:
SK_STORAGE_CREATE_FLAG_MASK BPF_LOCAL_STORAGE_CREATE_FLAG_MASK
BPF_SK_STORAGE_CACHE_SIZE BPF_LOCAL_STORAGE_CACHE_SIZE
MAX_VALUE_SIZE BPF_LOCAL_STORAGE_MAX_VALUE_SIZE
Structs:
bucket bpf_local_storage_map_bucket
bpf_sk_storage_map bpf_local_storage_map
bpf_sk_storage_data bpf_local_storage_data
bpf_sk_storage_elem bpf_local_storage_elem
bpf_sk_storage bpf_local_storage
The "sk" member in bpf_local_storage is also updated to "owner"
in preparation for changing the type to void * in a subsequent patch.
Functions:
selem_linked_to_sk selem_linked_to_storage
selem_alloc bpf_selem_alloc
__selem_unlink_sk bpf_selem_unlink_storage_nolock
__selem_link_sk bpf_selem_link_storage_nolock
selem_unlink_sk __bpf_selem_unlink_storage
sk_storage_update bpf_local_storage_update
__sk_storage_lookup bpf_local_storage_lookup
bpf_sk_storage_map_free bpf_local_storage_map_free
bpf_sk_storage_map_alloc bpf_local_storage_map_alloc
bpf_sk_storage_map_alloc_check bpf_local_storage_map_alloc_check
bpf_sk_storage_map_check_btf bpf_local_storage_map_check_btf
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-2-kpsingh@chromium.org
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The function consume_skb is only meaningful when tracing is enabled.
This patch makes it conditional on CONFIG_TRACEPOINTS.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Cited patch in fixes tag misses to protect port list traversal
while traversing per port reporter list.
Protect it using devlink instance lock.
Fixes: f4f541660121 ("devlink: Implement devlink health reporters on per-port basis")
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Cited patch in fixes tag initializes reporters_list and reporters_lock
of a devlink port after devlink port is added to the list. Once port
is added to the list, devlink_nl_cmd_health_reporter_get_dumpit()
can access the uninitialized mutex and reporters list head.
Fix it by initializing port reporters field before adding port to the
list.
Fixes: f4f541660121 ("devlink: Implement devlink health reporters on per-port basis")
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch is adapted from Eric's patch in an earlier discussion [1].
The TCP_SAVE_SYN currently only stores the network header and
tcp header. This patch allows it to optionally store
the mac header also if the setsockopt's optval is 2.
It requires one more bit for the "save_syn" bit field in tcp_sock.
This patch achieves this by moving the syn_smc bit next to the is_mptcp.
The syn_smc is currently used with the TCP experimental option. Since
syn_smc is only used when CONFIG_SMC is enabled, this patch also puts
the "IS_ENABLED(CONFIG_SMC)" around it like the is_mptcp did
with "IS_ENABLED(CONFIG_MPTCP)".
The mac_hdrlen is also stored in the "struct saved_syn"
to allow a quick offset from the bpf prog if it chooses to start
getting from the network header or the tcp header.
[1]: https://lore.kernel.org/netdev/CANn89iLJNWh6bkH7DNhy_kmcAexuUCccqERqe7z2QsvPhGrYPQ@mail.gmail.com/
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20200820190123.2886935-1-kafai@fb.com
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[ Note: The TCP changes here is mainly to implement the bpf
pieces into the bpf_skops_*() functions introduced
in the earlier patches. ]
The earlier effort in BPF-TCP-CC allows the TCP Congestion Control
algorithm to be written in BPF. It opens up opportunities to allow
a faster turnaround time in testing/releasing new congestion control
ideas to production environment.
The same flexibility can be extended to writing TCP header option.
It is not uncommon that people want to test new TCP header option
to improve the TCP performance. Another use case is for data-center
that has a more controlled environment and has more flexibility in
putting header options for internal only use.
For example, we want to test the idea in putting maximum delay
ACK in TCP header option which is similar to a draft RFC proposal [1].
This patch introduces the necessary BPF API and use them in the
TCP stack to allow BPF_PROG_TYPE_SOCK_OPS program to parse
and write TCP header options. It currently supports most of
the TCP packet except RST.
Supported TCP header option:
───────────────────────────
This patch allows the bpf-prog to write any option kind.
Different bpf-progs can write its own option by calling the new helper
bpf_store_hdr_opt(). The helper will ensure there is no duplicated
option in the header.
By allowing bpf-prog to write any option kind, this gives a lot of
flexibility to the bpf-prog. Different bpf-prog can write its
own option kind. It could also allow the bpf-prog to support a
recently standardized option on an older kernel.
Sockops Callback Flags:
──────────────────────
The bpf program will only be called to parse/write tcp header option
if the following newly added callback flags are enabled
in tp->bpf_sock_ops_cb_flags:
BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG
BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG
BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG
A few words on the PARSE CB flags. When the above PARSE CB flags are
turned on, the bpf-prog will be called on packets received
at a sk that has at least reached the ESTABLISHED state.
The parsing of the SYN-SYNACK-ACK will be discussed in the
"3 Way HandShake" section.
The default is off for all of the above new CB flags, i.e. the bpf prog
will not be called to parse or write bpf hdr option. There are
details comment on these new cb flags in the UAPI bpf.h.
sock_ops->skb_data and bpf_load_hdr_opt()
─────────────────────────────────────────
sock_ops->skb_data and sock_ops->skb_data_end covers the whole
TCP header and its options. They are read only.
The new bpf_load_hdr_opt() helps to read a particular option "kind"
from the skb_data.
Please refer to the comment in UAPI bpf.h. It has details
on what skb_data contains under different sock_ops->op.
3 Way HandShake
───────────────
The bpf-prog can learn if it is sending SYN or SYNACK by reading the
sock_ops->skb_tcp_flags.
* Passive side
When writing SYNACK (i.e. sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB),
the received SYN skb will be available to the bpf prog. The bpf prog can
use the SYN skb (which may carry the header option sent from the remote bpf
prog) to decide what bpf header option should be written to the outgoing
SYNACK skb. The SYN packet can be obtained by getsockopt(TCP_BPF_SYN*).
More on this later. Also, the bpf prog can learn if it is in syncookie
mode (by checking sock_ops->args[0] == BPF_WRITE_HDR_TCP_SYNACK_COOKIE).
The bpf prog can store the received SYN pkt by using the existing
bpf_setsockopt(TCP_SAVE_SYN). The example in a later patch does it.
[ Note that the fullsock here is a listen sk, bpf_sk_storage
is not very useful here since the listen sk will be shared
by many concurrent connection requests.
Extending bpf_sk_storage support to request_sock will add weight
to the minisock and it is not necessary better than storing the
whole ~100 bytes SYN pkt. ]
When the connection is established, the bpf prog will be called
in the existing PASSIVE_ESTABLISHED_CB callback. At that time,
the bpf prog can get the header option from the saved syn and
then apply the needed operation to the newly established socket.
The later patch will use the max delay ack specified in the SYN
header and set the RTO of this newly established connection
as an example.
The received ACK (that concludes the 3WHS) will also be available to
the bpf prog during PASSIVE_ESTABLISHED_CB through the sock_ops->skb_data.
It could be useful in syncookie scenario. More on this later.
There is an existing getsockopt "TCP_SAVED_SYN" to return the whole
saved syn pkt which includes the IP[46] header and the TCP header.
A few "TCP_BPF_SYN*" getsockopt has been added to allow specifying where to
start getting from, e.g. starting from TCP header, or from IP[46] header.
The new getsockopt(TCP_BPF_SYN*) will also know where it can get
the SYN's packet from:
- (a) the just received syn (available when the bpf prog is writing SYNACK)
and it is the only way to get SYN during syncookie mode.
or
- (b) the saved syn (available in PASSIVE_ESTABLISHED_CB and also other
existing CB).
The bpf prog does not need to know where the SYN pkt is coming from.
The getsockopt(TCP_BPF_SYN*) will hide this details.
Similarly, a flags "BPF_LOAD_HDR_OPT_TCP_SYN" is also added to
bpf_load_hdr_opt() to read a particular header option from the SYN packet.
* Fastopen
Fastopen should work the same as the regular non fastopen case.
This is a test in a later patch.
* Syncookie
For syncookie, the later example patch asks the active
side's bpf prog to resend the header options in ACK. The server
can use bpf_load_hdr_opt() to look at the options in this
received ACK during PASSIVE_ESTABLISHED_CB.
* Active side
The bpf prog will get a chance to write the bpf header option
in the SYN packet during WRITE_HDR_OPT_CB. The received SYNACK
pkt will also be available to the bpf prog during the existing
ACTIVE_ESTABLISHED_CB callback through the sock_ops->skb_data
and bpf_load_hdr_opt().
* Turn off header CB flags after 3WHS
If the bpf prog does not need to write/parse header options
beyond the 3WHS, the bpf prog can clear the bpf_sock_ops_cb_flags
to avoid being called for header options.
Or the bpf-prog can select to leave the UNKNOWN_HDR_OPT_CB_FLAG on
so that the kernel will only call it when there is option that
the kernel cannot handle.
[1]: draft-wang-tcpm-low-latency-opt-00
https://tools.ietf.org/html/draft-wang-tcpm-low-latency-opt-00
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200820190104.2885895-1-kafai@fb.com
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