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2014-06-26rtnetlink: fix userspace API breakage for iproute2 < v3.9.0Michal Schmidt
[ Upstream commit e5eca6d41f53db48edd8cf88a3f59d2c30227f8e ] When running RHEL6 userspace on a current upstream kernel, "ip link" fails to show VF information. The reason is a kernel<->userspace API change introduced by commit 88c5b5ce5cb57 ("rtnetlink: Call nlmsg_parse() with correct header length"), after which the kernel does not see iproute2's IFLA_EXT_MASK attribute in the netlink request. iproute2 adjusted for the API change in its commit 63338dca4513 ("libnetlink: Use ifinfomsg instead of rtgenmsg in rtnl_wilddump_req_filter"). The problem has been noticed before: http://marc.info/?l=linux-netdev&m=136692296022182&w=2 (Subject: Re: getting VF link info seems to be broken in 3.9-rc8) We can do better than tell those with old userspace to upgrade. We can recognize the old iproute2 in the kernel by checking the netlink message length. Even when including the IFLA_EXT_MASK attribute, its netlink message is shorter than struct ifinfomsg. With this patch "ip link" shows VF information in both old and new iproute2 versions. Signed-off-by: Michal Schmidt <mschmidt@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-06-26net: force a list_del() in unregister_netdevice_many()Eric Dumazet
[ Upstream commit 87757a917b0b3c0787e0563c679762152be81312 ] unregister_netdevice_many() API is error prone and we had too many bugs because of dangling LIST_HEAD on stacks. See commit f87e6f47933e3e ("net: dont leave active on stack LIST_HEAD") In fact, instead of making sure no caller leaves an active list_head, just force a list_del() in the callee. No one seems to need to access the list after unregister_netdevice_many() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-06-02net: filter: fix possible memory leak in __sk_prepare_filter()Leon Yu
__sk_prepare_filter() was reworked in commit bd4cf0ed3 (net: filter: rework/optimize internal BPF interpreter's instruction set) so that it should have uncharged memory once things went wrong. However that work isn't complete. Error is handled only in __sk_migrate_filter() while memory can still leak in the error path right after sk_chk_filter(). Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set") Signed-off-by: Leon Yu <chianglungyu@gmail.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Tested-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-01net: fix wrong mac_len calculation for vlansNikolay Aleksandrov
After 1e785f48d29a ("net: Start with correct mac_len in skb_network_protocol") skb->mac_len is used as a start of the calculation in skb_network_protocol() but that is not always correct. If skb->protocol == 8021Q/AD, usually the vlan header is already inserted in the skb (i.e. vlan reorder hdr == 0). Usually when the packet enters dev_hard_xmit it has mac_len == 0 so we take 2 bytes from the destination mac address (skb->data + VLAN_HLEN) as a type in skb_network_protocol() and return vlan_depth == 4. In the case where TSO is off, then the mac_len is set but it's == 18 (ETH_HLEN + VLAN_HLEN), so skb_network_protocol() returns a type from inside the packet and offset == 22. Also make vlan_depth unsigned as suggested before. As suggested by Eric Dumazet, move the while() loop in the if() so we can avoid additional testing in fast path. Here are few netperf tests + debug printk's to illustrate: cat netperf.tso-on.reorder-on.bugged - Vlan -> device (reorder on, default, this case is okay) MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.3.1 () port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 7111.54 [ 81.605435] skb->len 65226 skb->gso_size 1448 skb->proto 0x800 skb->mac_len 0 vlan_depth 0 type 0x800 - Vlan -> device (reorder off, bad) cat netperf.tso-on.reorder-off.bugged MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.3.1 () port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 241.35 [ 204.578332] skb->len 1518 skb->gso_size 0 skb->proto 0x8100 skb->mac_len 0 vlan_depth 4 type 0x5301 0x5301 are the last two bytes of the destination mac. And if we stop TSO, we may get even the following: [ 83.343156] skb->len 2966 skb->gso_size 1448 skb->proto 0x8100 skb->mac_len 18 vlan_depth 22 type 0xb84 Because mac_len already accounts for VLAN_HLEN. After the fix: cat netperf.tso-on.reorder-off.fixed MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.3.1 () port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.01 5001.46 [ 81.888489] skb->len 65230 skb->gso_size 1448 skb->proto 0x8100 skb->mac_len 0 vlan_depth 18 type 0x800 CC: Vlad Yasevich <vyasevic@redhat.com> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Daniel Borkman <dborkman@redhat.com> CC: David S. Miller <davem@davemloft.net> Fixes:1e785f48d29a ("net: Start with correct mac_len in skb_network_protocol") Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-16bonding: Fix stacked device detection in arp monitoringVlad Yasevich
Prior to commit fbd929f2dce460456807a51e18d623db3db9f077 bonding: support QinQ for bond arp interval the arp monitoring code allowed for proper detection of devices stacked on top of vlans. Since the above commit, the code can still detect a device stacked on top of single vlan, but not a device stacked on top of Q-in-Q configuration. The search will only set the inner vlan tag if the route device is the vlan device. However, this is not always the case, as it is possible to extend the stacked configuration. With this patch it is possible to provision devices on top Q-in-Q vlan configuration that should be used as a source of ARP monitoring information. For example: ip link add link bond0 vlan10 type vlan proto 802.1q id 10 ip link add link vlan10 vlan100 type vlan proto 802.1q id 100 ip link add link vlan100 type macvlan Note: This patch limites the number of stacked VLANs to 2, just like before. The original, however had another issue in that if we had more then 2 levels of VLANs, we would end up generating incorrectly tagged traffic. This is no longer possible. Fixes: fbd929f2dce460456807a51e18d623db3db9f077 (bonding: support QinQ for bond arp interval) CC: Jay Vosburgh <j.vosburgh@gmail.com> CC: Veaceslav Falico <vfalico@redhat.com> CC: Andy Gospodarek <andy@greyhouse.net> CC: Ding Tianhong <dingtianhong@huawei.com> CC: Patric McHardy <kaber@trash.net> Signed-off-by: Vlad Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-16vlan: Fix lockdep warning with stacked vlan devices.Vlad Yasevich
This reverts commit dc8eaaa006350d24030502a4521542e74b5cb39f. vlan: Fix lockdep warning when vlan dev handle notification Instead we use the new new API to find the lock subclass of our vlan device. This way we can support configurations where vlans are interspersed with other devices: bond -> vlan -> macvlan -> vlan Signed-off-by: Vlad Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-16net: Find the nesting level of a given device by type.Vlad Yasevich
Multiple devices in the kernel can be stacked/nested and they need to know their nesting level for the purposes of lockdep. This patch provides a generic function that determines a nesting level of a particular device by its type (ex: vlan, macvlan, etc). We only care about nesting of the same type of devices. For example: eth0 <- vlan0.10 <- macvlan0 <- vlan1.20 The nesting level of vlan1.20 would be 1, since there is another vlan in the stack under it. Signed-off-by: Vlad Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-16net: gro: make sure skb->cb[] initial content has not to be zeroEric Dumazet
Starting from linux-3.13, GRO attempts to build full size skbs. Problem is the commit assumed one particular field in skb->cb[] was clean, but it is not the case on some stacked devices. Timo reported a crash in case traffic is decrypted before reaching a GRE device. Fix this by initializing NAPI_GRO_CB(skb)->last at the right place, this also removes one conditional. Thanks a lot to Timo for providing full reports and bisecting this. Fixes: 8a29111c7ca6 ("net: gro: allow to build full sized skb") Bisected-by: Timo Teras <timo.teras@iki.fi> Signed-off-by: Eric Dumazet <edumazet@google.com> Tested-by: Timo Teräs <timo.teras@iki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-15rtnetlink: wait for unregistering devices in rtnl_link_unregister()Cong Wang
From: Cong Wang <cwang@twopensource.com> commit 50624c934db18ab90 (net: Delay default_device_exit_batch until no devices are unregistering) introduced rtnl_lock_unregistering() for default_device_exit_batch(). Same race could happen we when rmmod a driver which calls rtnl_link_unregister() as we call dev->destructor without rtnl lock. For long term, I think we should clean up the mess of netdev_run_todo() and net namespce exit code. Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-14net: avoid dependency of net_get_random_once on nop patchingHannes Frederic Sowa
net_get_random_once depends on the static keys infrastructure to patch up the branch to the slow path during boot. This was realized by abusing the static keys api and defining a new initializer to not enable the call site while still indicating that the branch point should get patched up. This was needed to have the fast path considered likely by gcc. The static key initialization during boot up normally walks through all the registered keys and either patches in ideal nops or enables the jump site but omitted that step on x86 if ideal nops where already placed at static_key branch points. Thus net_get_random_once branches not always became active. This patch switches net_get_random_once to the ordinary static_key api and thus places the kernel fast path in the - by gcc considered - unlikely path. Microbenchmarks on Intel and AMD x86-64 showed that the unlikely path actually beats the likely path in terms of cycle cost and that different nop patterns did not make much difference, thus this switch should not be noticeable. Fixes: a48e42920ff38b ("net: introduce new macro net_get_random_once") Reported-by: Tuomas Räsänen <tuomasjjrasanen@tjjr.fi> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-13neigh: set nud_state to NUD_INCOMPLETE when probing router reachabilityDuan Jiong
Since commit 7e98056964("ipv6: router reachability probing"), a router falls into NUD_FAILED will be probed. Now if function rt6_select() selects a router which neighbour state is NUD_FAILED, and at the same time function rt6_probe() changes the neighbour state to NUD_PROBE, then function dst_neigh_output() can directly send packets, but actually the neighbour still is unreachable. If we set nud_state to NUD_INCOMPLETE instead NUD_PROBE, packets will not be sent out until the neihbour is reachable. In addition, because the route should be probes with a single NS, so we must set neigh->probes to neigh_max_probes(), then the neigh timer timeout and function neigh_timer_handler() will not send other NS Messages. Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-07Revert "net: core: introduce netif_skb_dev_features"Florian Westphal
This reverts commit d206940319c41df4299db75ed56142177bb2e5f6, there are no more callers. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-24rtnetlink: Only supply IFLA_VF_PORTS information when RTEXT_FILTER_VF is setDavid Gibson
Since 115c9b81928360d769a76c632bae62d15206a94a (rtnetlink: Fix problem with buffer allocation), RTM_NEWLINK messages only contain the IFLA_VFINFO_LIST attribute if they were solicited by a GETLINK message containing an IFLA_EXT_MASK attribute with the RTEXT_FILTER_VF flag. That was done because some user programs broke when they received more data than expected - because IFLA_VFINFO_LIST contains information for each VF it can become large if there are many VFs. However, the IFLA_VF_PORTS attribute, supplied for devices which implement ndo_get_vf_port (currently the 'enic' driver only), has the same problem. It supplies per-VF information and can therefore become large, but it is not currently conditional on the IFLA_EXT_MASK value. Worse, it interacts badly with the existing EXT_MASK handling. When IFLA_EXT_MASK is not supplied, the buffer for netlink replies is fixed at NLMSG_GOODSIZE. If the information for IFLA_VF_PORTS exceeds this, then rtnl_fill_ifinfo() returns -EMSGSIZE on the first message in a packet. netlink_dump() will misinterpret this as having finished the listing and omit data for this interface and all subsequent ones. That can cause getifaddrs(3) to enter an infinite loop. This patch addresses the problem by only supplying IFLA_VF_PORTS when IFLA_EXT_MASK is supplied with the RTEXT_FILTER_VF flag set. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-24rtnetlink: Warn when interface's information won't fit in our packetDavid Gibson
Without IFLA_EXT_MASK specified, the information reported for a single interface in response to RTM_GETLINK is expected to fit within a netlink packet of NLMSG_GOODSIZE. If it doesn't, however, things will go badly wrong, When listing all interfaces, netlink_dump() will incorrectly treat -EMSGSIZE on the first message in a packet as the end of the listing and omit information for that interface and all subsequent ones. This can cause getifaddrs(3) to enter an infinite loop. This patch won't fix the problem, but it will WARN_ON() making it easier to track down what's going wrong. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Jiri Pirko <jpirko@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-24net: Use netlink_ns_capable to verify the permisions of netlink messagesEric W. Biederman
It is possible by passing a netlink socket to a more privileged executable and then to fool that executable into writing to the socket data that happens to be valid netlink message to do something that privileged executable did not intend to do. To keep this from happening replace bare capable and ns_capable calls with netlink_capable, netlink_net_calls and netlink_ns_capable calls. Which act the same as the previous calls except they verify that the opener of the socket had the desired permissions as well. Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-24net: Add variants of capable for use on on socketsEric W. Biederman
sk_net_capable - The common case, operations that are safe in a network namespace. sk_capable - Operations that are not known to be safe in a network namespace sk_ns_capable - The general case for special cases. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-24net: Move the permission check in sock_diag_put_filterinfo to packet_diag_dumpEric W. Biederman
The permission check in sock_diag_put_filterinfo is wrong, and it is so removed from it's sources it is not clear why it is wrong. Move the computation into packet_diag_dump and pass a bool of the result into sock_diag_filterinfo. This does not yet correct the capability check but instead simply moves it to make it clear what is going on. Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-23net: filter: initialize A and X registersAlexei Starovoitov
exisiting BPF verifier allows uninitialized access to registers, 'ret A' is considered to be a valid filter. So initialize A and X to zero to prevent leaking kernel memory In the future BPF verifier will be rejecting such filters Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Daniel Borkmann <dborkman@redhat.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-22net: Fix ns_capable check in sock_diag_put_filterinfoAndrew Lutomirski
The caller needs capabilities on the namespace being queried, not on their own namespace. This is a security bug, although it likely has only a minor impact. Cc: stable@vger.kernel.org Signed-off-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-18vlan: Fix lockdep warning when vlan dev handle notificationdingtianhong
When I open the LOCKDEP config and run these steps: modprobe 8021q vconfig add eth2 20 vconfig add eth2.20 30 ifconfig eth2 xx.xx.xx.xx then the Call Trace happened: [32524.386288] ============================================= [32524.386293] [ INFO: possible recursive locking detected ] [32524.386298] 3.14.0-rc2-0.7-default+ #35 Tainted: G O [32524.386302] --------------------------------------------- [32524.386306] ifconfig/3103 is trying to acquire lock: [32524.386310] (&vlan_netdev_addr_lock_key/1){+.....}, at: [<ffffffff814275f4>] dev_mc_sync+0x64/0xb0 [32524.386326] [32524.386326] but task is already holding lock: [32524.386330] (&vlan_netdev_addr_lock_key/1){+.....}, at: [<ffffffff8141af83>] dev_set_rx_mode+0x23/0x40 [32524.386341] [32524.386341] other info that might help us debug this: [32524.386345] Possible unsafe locking scenario: [32524.386345] [32524.386350] CPU0 [32524.386352] ---- [32524.386354] lock(&vlan_netdev_addr_lock_key/1); [32524.386359] lock(&vlan_netdev_addr_lock_key/1); [32524.386364] [32524.386364] *** DEADLOCK *** [32524.386364] [32524.386368] May be due to missing lock nesting notation [32524.386368] [32524.386373] 2 locks held by ifconfig/3103: [32524.386376] #0: (rtnl_mutex){+.+.+.}, at: [<ffffffff81431d42>] rtnl_lock+0x12/0x20 [32524.386387] #1: (&vlan_netdev_addr_lock_key/1){+.....}, at: [<ffffffff8141af83>] dev_set_rx_mode+0x23/0x40 [32524.386398] [32524.386398] stack backtrace: [32524.386403] CPU: 1 PID: 3103 Comm: ifconfig Tainted: G O 3.14.0-rc2-0.7-default+ #35 [32524.386409] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [32524.386414] ffffffff81ffae40 ffff8800d9625ae8 ffffffff814f68a2 ffff8800d9625bc8 [32524.386421] ffffffff810a35fb ffff8800d8a8d9d0 00000000d9625b28 ffff8800d8a8e5d0 [32524.386428] 000003cc00000000 0000000000000002 ffff8800d8a8e5f8 0000000000000000 [32524.386435] Call Trace: [32524.386441] [<ffffffff814f68a2>] dump_stack+0x6a/0x78 [32524.386448] [<ffffffff810a35fb>] __lock_acquire+0x7ab/0x1940 [32524.386454] [<ffffffff810a323a>] ? __lock_acquire+0x3ea/0x1940 [32524.386459] [<ffffffff810a4874>] lock_acquire+0xe4/0x110 [32524.386464] [<ffffffff814275f4>] ? dev_mc_sync+0x64/0xb0 [32524.386471] [<ffffffff814fc07a>] _raw_spin_lock_nested+0x2a/0x40 [32524.386476] [<ffffffff814275f4>] ? dev_mc_sync+0x64/0xb0 [32524.386481] [<ffffffff814275f4>] dev_mc_sync+0x64/0xb0 [32524.386489] [<ffffffffa0500cab>] vlan_dev_set_rx_mode+0x2b/0x50 [8021q] [32524.386495] [<ffffffff8141addf>] __dev_set_rx_mode+0x5f/0xb0 [32524.386500] [<ffffffff8141af8b>] dev_set_rx_mode+0x2b/0x40 [32524.386506] [<ffffffff8141b3cf>] __dev_open+0xef/0x150 [32524.386511] [<ffffffff8141b177>] __dev_change_flags+0xa7/0x190 [32524.386516] [<ffffffff8141b292>] dev_change_flags+0x32/0x80 [32524.386524] [<ffffffff8149ca56>] devinet_ioctl+0x7d6/0x830 [32524.386532] [<ffffffff81437b0b>] ? dev_ioctl+0x34b/0x660 [32524.386540] [<ffffffff814a05b0>] inet_ioctl+0x80/0xa0 [32524.386550] [<ffffffff8140199d>] sock_do_ioctl+0x2d/0x60 [32524.386558] [<ffffffff81401a52>] sock_ioctl+0x82/0x2a0 [32524.386568] [<ffffffff811a7123>] do_vfs_ioctl+0x93/0x590 [32524.386578] [<ffffffff811b2705>] ? rcu_read_lock_held+0x45/0x50 [32524.386586] [<ffffffff811b39e5>] ? __fget_light+0x105/0x110 [32524.386594] [<ffffffff811a76b1>] SyS_ioctl+0x91/0xb0 [32524.386604] [<ffffffff815057e2>] system_call_fastpath+0x16/0x1b ======================================================================== The reason is that all of the addr_lock_key for vlan dev have the same class, so if we change the status for vlan dev, the vlan dev and its real dev will hold the same class of addr_lock_key together, so the warning happened. we should distinguish the lock depth for vlan dev and its real dev. v1->v2: Convert the vlan_netdev_addr_lock_key to an array of eight elements, which could support to add 8 vlan id on a same vlan dev, I think it is enough for current scene, because a netdev's name is limited to IFNAMSIZ which could not hold 8 vlan id, and the vlan dev would not meet the same class key with its real dev. The new function vlan_dev_get_lockdep_subkey() will return the subkey and make the vlan dev could get a suitable class key. v2->v3: According David's suggestion, I use the subclass to distinguish the lock key for vlan dev and its real dev, but it make no sense, because the difference for subclass in the lock_class_key doesn't mean that the difference class for lock_key, so I use lock_depth to distinguish the different depth for every vlan dev, the same depth of the vlan dev could have the same lock_class_key, I import the MAX_LOCK_DEPTH from the include/linux/sched.h, I think it is enough here, the lockdep should never exceed that value. v3->v4: Add a huge array of locking keys will waste static kernel memory and is not a appropriate method, we could use _nested() variants to fix the problem, calculate the depth for every vlan dev, and use the depth as the subclass for addr_lock_key. Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-15ipv4: add a sock pointer to dst->output() path.Eric Dumazet
In the dst->output() path for ipv4, the code assumes the skb it has to transmit is attached to an inet socket, specifically via ip_mc_output() : The sk_mc_loop() test triggers a WARN_ON() when the provider of the packet is an AF_PACKET socket. The dst->output() method gets an additional 'struct sock *sk' parameter. This needs a cascade of changes so that this parameter can be propagated from vxlan to final consumer. Fixes: 8f646c922d55 ("vxlan: keep original skb ownership") Reported-by: lucien xin <lucien.xin@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-14net: Start with correct mac_len in skb_network_protocolVlad Yasevich
Sometimes, when the packet arrives at skb_mac_gso_segment() its skb->mac_len already accounts for some of the mac lenght headers in the packet. This seems to happen when forwarding through and OpenSSL tunnel. When we start looking for any vlan headers in skb_network_protocol() we seem to ignore any of the already known mac headers and start with an ETH_HLEN. This results in an incorrect offset, dropped TSO frames and general slowness of the connection. We can start counting from the known skb->mac_len and return at least that much if all mac level headers are known and accounted for. Fixes: 53d6471cef17262d3ad1c7ce8982a234244f68ec (net: Account for all vlan headers in skb_mac_gso_segment) CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Daniel Borkman <dborkman@redhat.com> Tested-by: Martin Filip <nexus+kernel@smoula.net> Signed-off-by: Vlad Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-14net: filter: seccomp: fix wrong decoding of BPF_S_ANC_SECCOMP_LD_WDaniel Borkmann
While reviewing seccomp code, we found that BPF_S_ANC_SECCOMP_LD_W has been wrongly decoded by commit a8fc927780 ("sk-filter: Add ability to get socket filter program (v2)") into the opcode BPF_LD|BPF_B|BPF_ABS although it should have been decoded as BPF_LD|BPF_W|BPF_ABS. In practice, this should not have much side-effect though, as such conversion is/was being done through prctl(2) PR_SET_SECCOMP. Reverse operation PR_GET_SECCOMP will only return the current seccomp mode, but not the filter itself. Since the transition to the new BPF infrastructure, it's also not used anymore, so we can simply remove this as it's unreachable. Fixes: a8fc927780 ("sk-filter: Add ability to get socket filter program (v2)") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-13filter: prevent nla extensions to peek beyond the end of the messageMathias Krause
The BPF_S_ANC_NLATTR and BPF_S_ANC_NLATTR_NEST extensions fail to check for a minimal message length before testing the supplied offset to be within the bounds of the message. This allows the subtraction of the nla header to underflow and therefore -- as the data type is unsigned -- allowing far to big offset and length values for the search of the netlink attribute. The remainder calculation for the BPF_S_ANC_NLATTR_NEST extension is also wrong. It has the minuend and subtrahend mixed up, therefore calculates a huge length value, allowing to overrun the end of the message while looking for the netlink attribute. The following three BPF snippets will trigger the bugs when attached to a UNIX datagram socket and parsing a message with length 1, 2 or 3. ,-[ PoC for missing size check in BPF_S_ANC_NLATTR ]-- | ld #0x87654321 | ldx #42 | ld #nla | ret a `--- ,-[ PoC for the same bug in BPF_S_ANC_NLATTR_NEST ]-- | ld #0x87654321 | ldx #42 | ld #nlan | ret a `--- ,-[ PoC for wrong remainder calculation in BPF_S_ANC_NLATTR_NEST ]-- | ; (needs a fake netlink header at offset 0) | ld #0 | ldx #42 | ld #nlan | ret a `--- Fix the first issue by ensuring the message length fulfills the minimal size constrains of a nla header. Fix the second bug by getting the math for the remainder calculation right. Fixes: 4738c1db15 ("[SKFILTER]: Add SKF_ADF_NLATTR instruction") Fixes: d214c7537b ("filter: add SKF_AD_NLATTR_NEST to look for nested..") Cc: Patrick McHardy <kaber@trash.net> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Mathias Krause <minipli@googlemail.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-12pktgen: be friendly to LLTX devicesDaniel Borkmann
Similarly to commit 43279500deca ("packet: respect devices with LLTX flag in direct xmit"), we can basically apply the very same to pktgen. This will help testing against LLTX devices such as dummy driver (or others), which only have a single netdevice txq and would otherwise require locking their txq from pktgen side while e.g. in dummy case, we would not need any locking. Fix this by making use of HARD_TX_{UN,}LOCK API, so that NETIF_F_LLTX will be respected. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-11net: Fix use after free by removing length arg from sk_data_ready callbacks.David S. Miller
Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-10net: core: don't account for udp header size when computing seglenFlorian Westphal
In case of tcp, gso_size contains the tcpmss. For UFO (udp fragmentation offloading) skbs, gso_size is the fragment payload size, i.e. we must not account for udp header size. Otherwise, when using virtio drivers, a to-be-forwarded UFO GSO packet will be needlessly fragmented in the forward path, because we think its individual segments are too large for the outgoing link. Fixes: fe6cc55f3a9a053 ("net: ip, ipv6: handle gso skbs in forwarding path") Cc: Eric Dumazet <eric.dumazet@gmail.com> Reported-by: Tobias Brunner <tobias@strongswan.org> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Pull more networking updates from David Miller: 1) If a VXLAN interface is created with no groups, we can crash on reception of packets. Fix from Mike Rapoport. 2) Missing includes in CPTS driver, from Alexei Starovoitov. 3) Fix string validations in isdnloop driver, from YOSHIFUJI Hideaki and Dan Carpenter. 4) Missing irq.h include in bnxw2x, enic, and qlcnic drivers. From Josh Boyer. 5) AF_PACKET transmit doesn't statistically count TX drops, from Daniel Borkmann. 6) Byte-Queue-Limit enabled drivers aren't handled properly in AF_PACKET transmit path, also from Daniel Borkmann. Same problem exists in pktgen, and Daniel fixed it there too. 7) Fix resource leaks in driver probe error paths of new sxgbe driver, from Francois Romieu. 8) Truesize of SKBs can gradually get more and more corrupted in NAPI packet recycling path, fix from Eric Dumazet. 9) Fix uniprocessor netfilter build, from Florian Westphal. In the longer term we should perhaps try to find a way for ARRAY_SIZE() to work even with zero sized array elements. 10) Fix crash in netfilter conntrack extensions due to mis-estimation of required extension space. From Andrey Vagin. 11) Since we commit table rule updates before trying to copy the counters back to userspace (it's the last action we perform), we really can't signal the user copy with an error as we are beyond the point from which we can unwind everything. This causes all kinds of use after free crashes and other mysterious behavior. From Thomas Graf. 12) Restore previous behvaior of div/mod by zero in BPF filter processing. From Daniel Borkmann. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (38 commits) net: sctp: wake up all assocs if sndbuf policy is per socket isdnloop: several buffer overflows netdev: remove potentially harmful checks pktgen: fix xmit test for BQL enabled devices net/at91_ether: avoid NULL pointer dereference tipc: Let tipc_release() return 0 at86rf230: fix MAX_CSMA_RETRIES parameter mac802154: fix duplicate #include headers sxgbe: fix duplicate #include headers net: filter: be more defensive on div/mod by X==0 netfilter: Can't fail and free after table replacement xen-netback: Trivial format string fix net: bcmgenet: Remove unnecessary version.h inclusion net: smc911x: Remove unused local variable bonding: Inactive slaves should keep inactive flag's value netfilter: nf_tables: fix wrong format in request_module() netfilter: nf_tables: set names cannot be larger than 15 bytes netfilter: nf_conntrack: reserve two bytes for nf_ct_ext->len netfilter: Add {ipt,ip6t}_osf aliases for xt_osf netfilter: x_tables: allow to use cgroup match for LOCAL_IN nf hooks ...
2014-04-07Merge tag 'cpu-hotplug-3.15-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull CPU hotplug notifiers registration fixes from Rafael Wysocki: "The purpose of this single series of commits from Srivatsa S Bhat (with a small piece from Gautham R Shenoy) touching multiple subsystems that use CPU hotplug notifiers is to provide a way to register them that will not lead to deadlocks with CPU online/offline operations as described in the changelog of commit 93ae4f978ca7f ("CPU hotplug: Provide lockless versions of callback registration functions"). The first three commits in the series introduce the API and document it and the rest simply goes through the users of CPU hotplug notifiers and converts them to using the new method" * tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits) net/iucv/iucv.c: Fix CPU hotplug callback registration net/core/flow.c: Fix CPU hotplug callback registration mm, zswap: Fix CPU hotplug callback registration mm, vmstat: Fix CPU hotplug callback registration profile: Fix CPU hotplug callback registration trace, ring-buffer: Fix CPU hotplug callback registration xen, balloon: Fix CPU hotplug callback registration hwmon, via-cputemp: Fix CPU hotplug callback registration hwmon, coretemp: Fix CPU hotplug callback registration thermal, x86-pkg-temp: Fix CPU hotplug callback registration octeon, watchdog: Fix CPU hotplug callback registration oprofile, nmi-timer: Fix CPU hotplug callback registration intel-idle: Fix CPU hotplug callback registration clocksource, dummy-timer: Fix CPU hotplug callback registration drivers/base/topology.c: Fix CPU hotplug callback registration acpi-cpufreq: Fix CPU hotplug callback registration zsmalloc: Fix CPU hotplug callback registration scsi, fcoe: Fix CPU hotplug callback registration scsi, bnx2fc: Fix CPU hotplug callback registration scsi, bnx2i: Fix CPU hotplug callback registration ...
2014-04-07netdev: remove potentially harmful checksVeaceslav Falico
Currently we're checking a variable for != NULL after actually dereferencing it, in netdev_lower_get_next_private*(). It's counter-intuitive at best, and can lead to faulty usage (as it implies that the variable can be NULL), so fix it by removing the useless checks. Reported-by: Daniel Borkmann <dborkman@redhat.com> CC: "David S. Miller" <davem@davemloft.net> CC: Eric Dumazet <edumazet@google.com> CC: Nicolas Dichtel <nicolas.dichtel@6wind.com> CC: Jiri Pirko <jiri@resnulli.us> CC: stephen hemminger <stephen@networkplumber.org> CC: Jerry Chu <hkchu@google.com> Signed-off-by: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-07pktgen: fix xmit test for BQL enabled devicesDaniel Borkmann
Similarly as in commit 8e2f1a63f221 ("packet: fix packet_direct_xmit for BQL enabled drivers"), we test for __QUEUE_STATE_STACK_XOFF bit in pktgen's xmit, which would not fully fill the device's TX ring for BQL drivers that use netdev_tx_sent_queue(). Fix is to use, similarly as we do in packet sockets, netif_xmit_frozen_or_drv_stopped() test. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-07net: filter: be more defensive on div/mod by X==0Daniel Borkmann
The old interpreter behaviour was that we returned with 0 whenever we found a division by 0 would take place. In the new interpreter we would currently just skip that instead and continue execution. It's true that a value of 0 as return might not be appropriate in all cases, but current users (socket filters -> drop packet, seccomp -> SECCOMP_RET_KILL, cls_bpf -> unclassified, etc) seem fine with that behaviour. Better this than undefined BPF program behaviour as it's expected that A contains the result of the division. In future, as more use cases open up, we could further adapt this return value to our needs, if necessary. So reintroduce return of 0 for division by 0 as in the old interpreter. Also in case of K which is guaranteed to be 32bit wide, sk_chk_filter() already takes care of preventing division by 0 invoked through K, so we can generally spare us these tests. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Reviewed-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-03net-gro: reset skb->truesize in napi_reuse_skb()Eric Dumazet
Recycling skb always had been very tough... This time it appears GRO layer can accumulate skb->truesize adjustments made by drivers when they attach a fragment to skb. skb_gro_receive() can only subtract from skb->truesize the used part of a fragment. I spotted this problem seeing TcpExtPruneCalled and TcpExtTCPRcvCollapsed that were unexpected with a recent kernel, where TCP receive window should be sized properly to accept traffic coming from a driver not overshooting skb->truesize. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-03Merge branch 'for-3.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "A lot updates for cgroup: - The biggest one is cgroup's conversion to kernfs. cgroup took after the long abandoned vfs-entangled sysfs implementation and made it even more convoluted over time. cgroup's internal objects were fused with vfs objects which also brought in vfs locking and object lifetime rules. Naturally, there are places where vfs rules don't fit and nasty hacks, such as credential switching or lock dance interleaving inode mutex and cgroup_mutex with object serial number comparison thrown in to decide whether the operation is actually necessary, needed to be employed. After conversion to kernfs, internal object lifetime and locking rules are mostly isolated from vfs interactions allowing shedding of several nasty hacks and overall simplification. This will also allow implmentation of operations which may affect multiple cgroups which weren't possible before as it would have required nesting i_mutexes. - Various simplifications including dropping of module support, easier cgroup name/path handling, simplified cgroup file type handling and task_cg_lists optimization. - Prepatory changes for the planned unified hierarchy, which is still a patchset away from being actually operational. The dummy hierarchy is updated to serve as the default unified hierarchy. Controllers which aren't claimed by other hierarchies are associated with it, which BTW was what the dummy hierarchy was for anyway. - Various fixes from Li and others. This pull request includes some patches to add missing slab.h to various subsystems. This was triggered xattr.h include removal from cgroup.h. cgroup.h indirectly got included a lot of files which brought in xattr.h which brought in slab.h. There are several merge commits - one to pull in kernfs updates necessary for converting cgroup (already in upstream through driver-core), others for interfering changes in the fixes branch" * 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (74 commits) cgroup: remove useless argument from cgroup_exit() cgroup: fix spurious lockdep warning in cgroup_exit() cgroup: Use RCU_INIT_POINTER(x, NULL) in cgroup.c cgroup: break kernfs active_ref protection in cgroup directory operations cgroup: fix cgroup_taskset walking order cgroup: implement CFTYPE_ONLY_ON_DFL cgroup: make cgrp_dfl_root mountable cgroup: drop const from @buffer of cftype->write_string() cgroup: rename cgroup_dummy_root and related names cgroup: move ->subsys_mask from cgroupfs_root to cgroup cgroup: treat cgroup_dummy_root as an equivalent hierarchy during rebinding cgroup: remove NULL checks from [pr_cont_]cgroup_{name|path}() cgroup: use cgroup_setup_root() to initialize cgroup_dummy_root cgroup: reorganize cgroup bootstrapping cgroup: relocate setting of CGRP_DEAD cpuset: use rcu_read_lock() to protect task_cs() cgroup_freezer: document freezer_fork() subtleties cgroup: update cgroup_transfer_tasks() to either succeed or fail cgroup: drop task_lock() protection around task->cgroups cgroup: update how a newly forked task gets associated with css_set ...
2014-04-03net: add busy_poll device featureJiri Pirko
Currently there is no way how to find out if a device supports busy polling. So add a feature and make it dependent on ndo_busy_poll existence. Signed-off-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-02Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds
Pull networking updates from David Miller: "Here is my initial pull request for the networking subsystem during this merge window: 1) Support for ESN in AH (RFC 4302) from Fan Du. 2) Add full kernel doc for ethtool command structures, from Ben Hutchings. 3) Add BCM7xxx PHY driver, from Florian Fainelli. 4) Export computed TCP rate information in netlink socket dumps, from Eric Dumazet. 5) Allow IPSEC SA to be dumped partially using a filter, from Nicolas Dichtel. 6) Convert many drivers to pci_enable_msix_range(), from Alexander Gordeev. 7) Record SKB timestamps more efficiently, from Eric Dumazet. 8) Switch to microsecond resolution for TCP round trip times, also from Eric Dumazet. 9) Clean up and fix 6lowpan fragmentation handling by making use of the existing inet_frag api for it's implementation. 10) Add TX grant mapping to xen-netback driver, from Zoltan Kiss. 11) Auto size SKB lengths when composing netlink messages based upon past message sizes used, from Eric Dumazet. 12) qdisc dumps can take a long time, add a cond_resched(), From Eric Dumazet. 13) Sanitize netpoll core and drivers wrt. SKB handling semantics. Get rid of never-used-in-tree netpoll RX handling. From Eric W Biederman. 14) Support inter-address-family and namespace changing in VTI tunnel driver(s). From Steffen Klassert. 15) Add Altera TSE driver, from Vince Bridgers. 16) Optimizing csum_replace2() so that it doesn't adjust the checksum by checksumming the entire header, from Eric Dumazet. 17) Expand BPF internal implementation for faster interpreting, more direct translations into JIT'd code, and much cleaner uses of BPF filtering in non-socket ocntexts. From Daniel Borkmann and Alexei Starovoitov" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1976 commits) netpoll: Use skb_irq_freeable to make zap_completion_queue safe. net: Add a test to see if a skb is freeable in irq context qlcnic: Fix build failure due to undefined reference to `vxlan_get_rx_port' net: ptp: move PTP classifier in its own file net: sxgbe: make "core_ops" static net: sxgbe: fix logical vs bitwise operation net: sxgbe: sxgbe_mdio_register() frees the bus Call efx_set_channels() before efx->type->dimension_resources() xen-netback: disable rogue vif in kthread context net/mlx4: Set proper build dependancy with vxlan be2net: fix build dependency on VxLAN mac802154: make csma/cca parameters per-wpan mac802154: allow only one WPAN to be up at any given time net: filter: minor: fix kdoc in __sk_run_filter netlink: don't compare the nul-termination in nla_strcmp can: c_can: Avoid led toggling for every packet. can: c_can: Simplify TX interrupt cleanup can: c_can: Store dlc private can: c_can: Reduce register access can: c_can: Make the code readable ...
2014-04-02Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree updates from Jiri Kosina: "Usual rocket science -- mostly documentation and comment updates" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: sparse: fix comment doc: fix double words isdn: capi: fix "CAPI_VERSION" comment doc: DocBook: Fix typos in xml and template file Bluetooth: add module name for btwilink driver core: unexport static function create_syslog_header mmc: core: typo fix in printk specifier ARM: spear: clean up editing mistake net-sysfs: fix comment typo 'CONFIG_SYFS' doc: Insert MODULE_ in module-signing macros Documentation: update URL to hfsplus Technote 1150 gpio: update path to documentation ixgbe: Fix format string in ixgbe_fcoe. Kconfig: Remove useless "default N" lines user_namespace.c: Remove duplicated word in comment CREDITS: fix formatting treewide: Fix typo in Documentation/DocBook mm: Fix warning on make htmldocs caused by slab.c ata: ata-samsung_cf: cleanup in header file idr: remove unused prototype of idr_free()
2014-04-01Merge branch 'for-3.15/core' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull core block layer updates from Jens Axboe: "This is the pull request for the core block IO bits for the 3.15 kernel. It's a smaller round this time, it contains: - Various little blk-mq fixes and additions from Christoph and myself. - Cleanup of the IPI usage from the block layer, and associated helper code. From Frederic Weisbecker and Jan Kara. - Duplicate code cleanup in bio-integrity from Gu Zheng. This will give you a merge conflict, but that should be easy to resolve. - blk-mq notify spinlock fix for RT from Mike Galbraith. - A blktrace partial accounting bug fix from Roman Pen. - Missing REQ_SYNC detection fix for blk-mq from Shaohua Li" * 'for-3.15/core' of git://git.kernel.dk/linux-block: (25 commits) blk-mq: add REQ_SYNC early rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlock blk-mq: support partial I/O completions blk-mq: merge blk_mq_insert_request and blk_mq_run_request blk-mq: remove blk_mq_alloc_rq blk-mq: don't dump CPU -> hw queue map on driver load blk-mq: fix wrong usage of hctx->state vs hctx->flags blk-mq: allow blk_mq_init_commands() to return failure block: remove old blk_iopoll_enabled variable blktrace: fix accounting of partially completed requests smp: Rename __smp_call_function_single() to smp_call_function_single_async() smp: Remove wait argument from __smp_call_function_single() watchdog: Simplify a little the IPI call smp: Move __smp_call_function_single() below its safe version smp: Consolidate the various smp_call_function_single() declensions smp: Teach __smp_call_function_single() to check for offline cpus smp: Remove unused list_head from csd smp: Iterate functions through llist_for_each_entry_safe() block: Stop abusing rq->csd.list in blk-softirq block: Remove useless IPI struct initialization ...
2014-04-01netpoll: Use skb_irq_freeable to make zap_completion_queue safe.Eric W. Biederman
Replace the test in zap_completion_queue to test when it is safe to free skbs in hard irq context with skb_irq_freeable ensuring we only free skbs when it is safe, and removing the possibility of subtle problems. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-01net: ptp: move PTP classifier in its own fileDaniel Borkmann
This commit fixes a build error reported by Fengguang, that is triggered when CONFIG_NETWORK_PHY_TIMESTAMPING is not set: ERROR: "ptp_classify_raw" [drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe.ko] undefined! The fix is to introduce its own file for the PTP BPF classifier, so that PTP_1588_CLOCK and/or NETWORK_PHY_TIMESTAMPING can select it independently from each other. IXP4xx driver on ARM needs to select it as well since it does not seem to select PTP_1588_CLOCK or similar that would pull it in automatically. This also allows for hiding all of the internals of the BPF PTP program inside that file, and only exporting relevant API bits to drivers. This patch also adds a kdoc documentation of ptp_classify_raw() API to make it clear that it can return PTP_CLASS_* defines. Also, the BPF program has been translated into bpf_asm code, so that it can be more easily read and altered (extensively documented in [1]). In the kernel tree under tools/net/ we have bpf_asm and bpf_dbg tools, so the commented program can simply be translated via `./bpf_asm -c prog` where prog is a file that contains t