This patch added a new member csum_reqd in struct mptcp_out_options and
struct mptcp_subflow_request_sock. Initialized it with the helper
function mptcp_is_checksum_enabled().

In mptcp_write_options, if this field is enabled, send out the MP_CAPABLE
suboption with the MPTCP_CAP_CHECKSUM_REQD flag.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

when Linux receives an echo-ed ADD_ADDR, it checks the IP address against
the list of "announced" addresses. In case of a positive match, the timer
that handles retransmissions is stopped regardless of the 'Address Id' in
the received packet: this behaviour does not comply with RFC8684 3.4.1.

Fix it by validating the 'Address Id' in received echo-ed ADD_ADDRs.
Tested using packetdrill, with the following captured output:

 unpatched kernel:

 Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0xfd2e62517888fe29,mptcp dss ack 3007449509], length 0
 In  <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 1 1.2.3.4,mptcp dss ack 3013740213], length 0
 Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0xfd2e62517888fe29,mptcp dss ack 3007449509], length 0
 In  <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 90 198.51.100.2,mptcp dss ack 3013740213], length 0
        ^^^ retransmission is stopped here, but 'Address Id' is 90

 patched kernel:

 Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0x1cf372d59e05f4b8,mptcp dss ack 3007449509], length 0
 In  <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 1 1.2.3.4,mptcp dss ack 1672384568], length 0
 Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0x1cf372d59e05f4b8,mptcp dss ack 3007449509], length 0
 In  <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 90 198.51.100.2,mptcp dss ack 1672384568], length 0
 Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0x1cf372d59e05f4b8,mptcp dss ack 3007449509], length 0
 In  <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 1 198.51.100.2,mptcp dss ack 1672384568], length 0
        ^^^ retransmission is stopped here, only when both 'Address Id' and 'IP Address' match

Fixes: 00cfd77b ("mptcp: retransmit ADD_ADDR when timeout")
Signed-off-by: NDavide Caratti <dcaratti@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a left-over of early day. A malicious peer can flood
the kernel logs with useless messages, just drop it.

Fixes: f296234c ("mptcp: Add handling of incoming MP_JOIN requests")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added a tracepoint in ack_update_msk() to track the
incoming data_ack and window/snd_una updates.
Suggested-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Current Linux carries echo-ed ADD_ADDR over pure TCP ACKs, so there is no
need to add a DSS element that would fit only ADD_ADDR with IPv4 address.
Drop the DSS from echo-ed ADD_ADDR, regardless of the IP version.
Signed-off-by: NDavide Caratti <dcaratti@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The length of the IPv4 address is 4 octets and IPv6 is 16. That's the only
difference between add_addr_generate_hmac and add_addr6_generate_hmac.

This patch dropped the duplicate code and unify them into one.
Co-developed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since the type of the address family in struct mptcp_options_received
became sa_family_t, we should set AF_INET/AF_INET6 to it, instead of
using MPTCP_ADDR_IPVERSION_4/6.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added a new struct mptcp_addr_info member addr in struct
mptcp_options_received, and dropped the original family, addr_id, addr,
addr6 and port fields in it. Then we can pass the parameter mp_opt.addr
directly to mptcp_pm_add_addr_received and mptcp_pm_add_addr_echoed.

Since the port number became big-endian now, use htons to convert the
incoming port number to it. Also use ntohs to convert it when passing
it to add_addr_generate_hmac or printing it out.
Co-developed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since the family field was added in struct mptcp_out_options, no need to
use OPTION_MPTCP_ADD_ADDR6 to identify the IPv6 address. Drop it.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch moved the mptcp_addr_info struct from protocol.h to mptcp.h,
added a new struct mptcp_addr_info member addr in struct mptcp_out_options,
and dropped the original addr, addr6, addr_id and port fields in it. Then
we can use opts->addr to get the adding address from PM directly using
mptcp_pm_add_addr_signal.

Since the port number became big-endian now, use ntohs to convert it
before sending it out with the ADD_ADDR suboption. Also convert it
when passing it to add_addr_generate_hmac or printing it out.
Co-developed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The MPTCP reset option allows to carry a mptcp-specific error code that
provides more information on the nature of a connection reset.

Reset option data received gets stored in the subflow context so it can
be sent to userspace via the 'subflow closed' netlink event.

When a subflow is closed, the desired error code that should be sent to
the peer is also placed in the subflow context structure.

If a reset is sent before subflow establishment could complete, e.g. on
HMAC failure during an MP_JOIN operation, the mptcp skb extension is
used to store the reset information.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently we explicitly check for the first subflow being
NULL in a couple of places, even if we don't need any
special actions in such scenario.

Just drop the unneeded checks, to avoid confusion.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When an invalid address was announced, the subflow couldn't be created
for this address. Therefore mptcp_pm_nl_subflow_established couldn't be
invoked. Then the next addresses in the local address list didn't have a
chance to be announced.

This patch invokes the new function mptcp_pm_add_addr_echoed when the
address is echoed. In it, use mptcp_lookup_anno_list_by_saddr to check
whether this address is in the anno_list. If it is, PM schedules the
status MPTCP_PM_SUBFLOW_ESTABLISHED to invoke
mptcp_pm_create_subflow_or_signal_addr to deal with the next address in
the local address list.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch drops the unused parameter subflow in
mptcp_pm_subflow_established().

Fixes: 926bdeab ("mptcp: Implement path manager interface commands")
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, Linux computes the HMAC contained in ADD_ADDR sub-option using
the Address Id and the IP Address, and hardcodes a destination port equal
to zero. This is not ok for ADD_ADDR with port: ensure to account for the
endpoint port when computing the HMAC, in compliance with RFC8684 §3.4.1.

Fixes: 22fb85ff ("mptcp: add port support for ADD_ADDR suboption writing")
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Acked-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NDavide Caratti <dcaratti@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch changed the member rm_id in struct mptcp_options_received as a
list of the removing address ids, and renamed it to rm_list.

In mptcp_parse_option, parsed the RM_ADDR suboption and filled them into
the rm_list in struct mptcp_options_received.

In mptcp_incoming_options, passed this rm_list to the function
mptcp_pm_rm_addr_received.

It also changed the parameter type of mptcp_pm_rm_addr_received.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch defined a new struct mptcp_rm_list, the ids field was an
array of the removing address ids, the nr field was the valid number of
removing address ids in the array. The array size was definced as a new
macro MPTCP_RM_IDS_MAX. Changed the member rm_id of struct
mptcp_out_options to rm_list.

In mptcp_established_options_rm_addr, invoked mptcp_pm_rm_addr_signal to
get the rm_list. According the number of addresses in it, calculated
the padded RM_ADDR suboption length. And saved the ids array in struct
mptcp_out_options's rm_list member.

In mptcp_write_options, iterated each address id from struct
mptcp_out_options's rm_list member, set the invalid ones as TCPOPT_NOP,
then filled them into the RM_ADDR suboption.

Changed TCPOLEN_MPTCP_RM_ADDR_BASE from 4 to 3.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If the msk is closed before sending or receiving any data,
no DATA_FIN is generated, instead an MPC ack packet is
crafted out.

In the above scenario, the MPTCP protocol creates and sends a
pure ack and such packets matches also the criteria for an
MPC ack and the protocol tries first to insert MPC options,
leading to the described error.

This change addresses the issue by avoiding the insertion of an
MPC option for DATA_FIN packets or if the sub-flow is not
established.

To avoid doing multiple times the same test, fetch the data_fin
flag in a bool variable and pass it to both the interested
helpers.

Fixes: 6d0060f6 ("mptcp: Write MPTCP DSS headers to outgoing data packets")
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Pass the first/initial subflow to the existing functions so they can
pass this on to the notification handler that is added later in the
series.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently we do not schedule the MPTCP retransmission
timer after pushing the data when such action happens
in the subflow context.

This may cause hang-up on active-backup scenarios, or
even when only single subflow msks are involved, if we lost
some peer's ack.

Fixes: 6e628cd3 ("mptcp: use mptcp release_cb for delayed tasks")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move mptcp_cleanup_rbuf() related checks inside the mentioned
helper and extend them to mirror TCP checks more closely.

Additionally drop the 'rmem_pending' hack, since commit 87952603
("mptcp: protect the rx path with the msk socket spinlock") we
can use instead 'rmem_released'.

Fixes: ea4ca586 ("mptcp: refine MPTCP-level ack scheduling")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds the mibs for ADD_ADDR with port:

MPTCP_MIB_PORTADD for received ADD_ADDR suboption with a port number.

MPTCP_MIB_PORTSYNRX, MPTCP_MIB_PORTSYNACKRX, MPTCP_MIB_PORTACKRX, for
received MP_JOIN's SYN or SYN/ACK or ACK with a port number which is
different from the msk's port number.

MPTCP_MIB_MISMATCHPORTSYNRX and MPTCP_MIB_MISMATCHPORTACKRX, for
received SYN or ACK MP_JOIN with a mismatched port-number.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

With version 0 of the protocol it was legal to encode the 'Subflow Id' in
the MP_PRIO suboption, to specify which subflow would change its 'Backup'
flag. This has been removed from v1 specification: thus, according to RFC
8684 §3.3.8, the resulting 'Length' for MP_PRIO changed from 4 to 3 byte.

Current Linux generates / parses MP_PRIO according to the old spec, using
'Length' equal to 4, and hardcoding 1 as 'Subflow Id'; RFC compliance can
improve if we change 'Length' in other to become 3, leaving a 'Nop' after
the MP_PRIO suboption. In this way the kernel will emit and accept *only*
MP_PRIO suboptions that are compliant to version 1 of the MPTCP protocol.

 unpatched 5.11-rc kernel:
 [root@bottarga ~]# tcpdump -tnnr unpatched.pcap | grep prio
 reading from file unpatched.pcap, link-type LINUX_SLL (Linux cooked v1)
 dropped privs to tcpdump
 IP 10.0.3.2.48433 > 10.0.1.1.10006: Flags [.], ack 1, win 502, options [nop,nop,TS val 4032325513 ecr 1876514270,mptcp prio non-backup id 1,mptcp dss ack 14084896651682217737], length 0

 patched 5.11-rc kernel:
 [root@bottarga ~]# tcpdump -tnnr patched.pcap | grep prio
 reading from file patched.pcap, link-type LINUX_SLL (Linux cooked v1)
 dropped privs to tcpdump
 IP 10.0.3.2.49735 > 10.0.1.1.10006: Flags [.], ack 1, win 502, options [nop,nop,TS val 1276737699 ecr 2686399734,mptcp prio non-backup,nop,mptcp dss ack 18433038869082491686], length 0

Changes since v2:
 - when accounting for option space, don't increment 'TCPOLEN_MPTCP_PRIO'
   and use 'TCPOLEN_MPTCP_PRIO_ALIGN' instead, thanks to Matthieu Baerts.
Changes since v1:
 - refactor patch to avoid using 'TCPOLEN_MPTCP_PRIO' with its old value,
   thanks to Geliang Tang.

Fixes: 06706542 ("mptcp: add the outgoing MP_PRIO support")
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NDavide Caratti <dcaratti@redhat.com>
Reviewed-by: NMatteo Croce <mcroce@linux.microsoft.com>
Link: https://lore.kernel.org/r/846cdd41e6ad6ec88ef23fee1552ab39c2f5a3d1.1612184361.git.dcaratti@redhat.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

This patch added the mibs for MP_PRIO, MPTCP_MIB_MPPRIOTX for transmitting
of the MP_PRIO suboption, and MPTCP_MIB_MPPRIORX for receiving of it.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

This patch added the incoming MP_PRIO logic:

Added a flag named mp_prio in struct mptcp_options_received, to mark the
MP_PRIO is received, and save the priority value to struct
mptcp_options_received's backup member. Then invoke
mptcp_pm_mp_prio_received with the receiving subsocket and the backup
value.

In mptcp_pm_mp_prio_received, get the subflow context according the input
subsocket, and change the subflow's backup as the incoming priority value.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

This patch added the outgoing MP_PRIO logic:

In mptcp_pm_nl_mp_prio_send_ack, find the related subflow and subsocket
according to the input parameter addr. Save the input priority value to
suflow's backup, then set subflow's send_mp_prio flag to true, and save
the input priority value to suflow's request_bkup. Finally, send out a
pure ACK on the related subsocket.

In mptcp_established_options_mp_prio, check whether the subflow's
send_mp_prio is set. If it is, this is the packet for sending MP_PRIO.
So save subflow->request_bkup value to mptcp_out_options's backup, and
change the option type to OPTION_MPTCP_PRIO.

In mptcp_write_options, clear the send_mp_prio flag and send out the
MP_PRIO suboption with mptcp_out_options's backup value.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

When multiple subflows are active, we can receive a
window update on subflow with no write space available.
MPTCP will try to push frames on such subflow and will
fail. Pending frames will be pushed only after receiving
a window update on a subflow with some wspace available.

Overall the above could lead to suboptimal aggregate
bandwidth usage.

Instead, we should try to push pending frames as soon as
the subflow reaches both conditions mentioned above.

We can finally enable self-tests with asymmetric links,
as the above makes them finally pass.

Fixes: 6f8a612a ("mptcp: keep track of advertised windows right edge")
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

This patch cleared use_ack and use_map when dropping other suboptions to
fix the following syzkaller BUG:

[   15.223006] BUG: unable to handle page fault for address: 0000000000223b10
[   15.223700] #PF: supervisor read access in kernel mode
[   15.224209] #PF: error_code(0x0000) - not-present page
[   15.224724] PGD b8d5067 P4D b8d5067 PUD c0a5067 PMD 0
[   15.225237] Oops: 0000 [#1] SMP
[   15.225556] CPU: 0 PID: 7747 Comm: syz-executor Not tainted 5.10.0-rc6+ #24
[   15.226281] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[   15.227292] RIP: 0010:skb_release_data+0x89/0x1e0
[   15.227816] Code: 5b 5d 41 5c 41 5d 41 5e 41 5f e9 02 06 8a ff e8 fd 05 8a ff 45 31 ed 80 7d 02 00 4c 8d 65 30 74 55 e8 eb 05 8a ff 49 8b 1c 24 <4c> 8b 7b 08 41 f6 c7 01 0f 85 18 01 00 00 e8 d4 05 8a ff 8b 43 34
[   15.229669] RSP: 0018:ffffc900019c7c08 EFLAGS: 00010293
[   15.230188] RAX: ffff88800daad900 RBX: 0000000000223b08 RCX: 0000000000000006
[   15.230895] RDX: 0000000000000000 RSI: ffffffff818e06c5 RDI: ffff88807f6dc700
[   15.231593] RBP: ffff88807f71a4c0 R08: 0000000000000001 R09: 0000000000000001
[   15.232299] R10: ffffc900019c7c18 R11: 0000000000000000 R12: ffff88807f71a4f0
[   15.233007] R13: 0000000000000000 R14: ffff88807f6dc700 R15: 0000000000000002
[   15.233714] FS:  00007f65d9b5f700(0000) GS:ffff88807c400000(0000) knlGS:0000000000000000
[   15.234509] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   15.235081] CR2: 0000000000223b10 CR3: 000000000b883000 CR4: 00000000000006f0
[   15.235788] Call Trace:
[   15.236042]  skb_release_all+0x28/0x30
[   15.236419]  __kfree_skb+0x11/0x20
[   15.236768]  tcp_data_queue+0x270/0x1240
[   15.237161]  ? tcp_urg+0x50/0x2a0
[   15.237496]  tcp_rcv_established+0x39a/0x890
[   15.237997]  ? mark_held_locks+0x49/0x70
[   15.238467]  tcp_v4_do_rcv+0xb9/0x270
[   15.238915]  __release_sock+0x8a/0x160
[   15.239365]  release_sock+0x32/0xd0
[   15.239793]  __inet_stream_connect+0x1d2/0x400
[   15.240313]  ? do_wait_intr_irq+0x80/0x80
[   15.240791]  inet_stream_connect+0x36/0x50
[   15.241275]  mptcp_stream_connect+0x69/0x1b0
[   15.241787]  __sys_connect+0x122/0x140
[   15.242236]  ? syscall_enter_from_user_mode+0x17/0x50
[   15.242836]  ? lockdep_hardirqs_on_prepare+0xd4/0x170
[   15.243436]  __x64_sys_connect+0x1a/0x20
[   15.243924]  do_syscall_64+0x33/0x40
[   15.244313]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   15.244821] RIP: 0033:0x7f65d946e469
[   15.245183] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ff 49 2b 00 f7 d8 64 89 01 48
[   15.247019] RSP: 002b:00007f65d9b5eda8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
[   15.247770] RAX: ffffffffffffffda RBX: 000000000049bf00 RCX: 00007f65d946e469
[   15.248471] RDX: 0000000000000010 RSI: 00000000200000c0 RDI: 0000000000000005
[   15.249205] RBP: 000000000049bf00 R08: 0000000000000000 R09: 0000000000000000
[   15.249908] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049bf0c
[   15.250603] R13: 00007fffe8a25cef R14: 00007f65d9b3f000 R15: 0000000000000003
[   15.251312] Modules linked in:
[   15.251626] CR2: 0000000000223b10
[   15.251965] BUG: kernel NULL pointer dereference, address: 0000000000000048
[   15.252005] ---[ end trace f5c51fe19123c773 ]---
[   15.252822] #PF: supervisor read access in kernel mode
[   15.252823] #PF: error_code(0x0000) - not-present page
[   15.252825] PGD c6c6067 P4D c6c6067 PUD c0d8067
[   15.253294] RIP: 0010:skb_release_data+0x89/0x1e0
[   15.253910] PMD 0
[   15.253914] Oops: 0000 [#2] SMP
[   15.253917] CPU: 1 PID: 7746 Comm: syz-executor Tainted: G      D           5.10.0-rc6+ #24
[   15.253920] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[   15.254435] Code: 5b 5d 41 5c 41 5d 41 5e 41 5f e9 02 06 8a ff e8 fd 05 8a ff 45 31 ed 80 7d 02 00 4c 8d 65 30 74 55 e8 eb 05 8a ff 49 8b 1c 24 <4c> 8b 7b 08 41 f6 c7 01 0f 85 18 01 00 00 e8 d4 05 8a ff 8b 43 34
[   15.254899] RIP: 0010:skb_release_data+0x89/0x1e0
[   15.254902] Code: 5b 5d 41 5c 41 5d 41 5e 41 5f e9 02 06 8a ff e8 fd 05 8a ff 45 31 ed 80 7d 02 00 4c 8d 65 30 74 55 e8 eb 05 8a ff 49 8b 1c 24 <4c> 8b 7b 08 41 f6 c7 01 0f 85 18 01 00 00 e8 d4 05 8a ff 8b 43 34
[   15.254905] RSP: 0018:ffffc900019bfc08 EFLAGS: 00010293
[   15.255376] RSP: 0018:ffffc900019c7c08 EFLAGS: 00010293
[   15.255580]
[   15.255583] RAX: ffff888004a7ac80 RBX: 0000000000000040 RCX: 0000000000000000
[   15.255912]
[   15.256724] RDX: 0000000000000000 RSI: ffffffff818e06c5 RDI: ffff88807f6ddd00
[   15.257620] RAX: ffff88800daad900 RBX: 0000000000223b08 RCX: 0000000000000006
[   15.259817] RBP: ffff88800e9006c0 R08: 0000000000000000 R09: 0000000000000000
[   15.259818] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88800e9006f0
[   15.259820] R13: 0000000000000000 R14: ffff88807f6ddd00 R15: 0000000000000002
[   15.259822] FS:  00007fae4a60a700(0000) GS:ffff88807c500000(0000) knlGS:0000000000000000
[   15.259826] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   15.260296] RDX: 0000000000000000 RSI: ffffffff818e06c5 RDI: ffff88807f6dc700
[   15.262514] CR2: 0000000000000048 CR3: 000000000b89c000 CR4: 00000000000006e0
[   15.262515] Call Trace:
[   15.262519]  skb_release_all+0x28/0x30
[   15.262523]  __kfree_skb+0x11/0x20
[   15.263054] RBP: ffff88807f71a4c0 R08: 0000000000000001 R09: 0000000000000001
[   15.263680]  tcp_data_queue+0x270/0x1240
[   15.263843] R10: ffffc900019c7c18 R11: 0000000000000000 R12: ffff88807f71a4f0
[   15.264693]  ? tcp_urg+0x50/0x2a0
[   15.264856] R13: 0000000000000000 R14: ffff88807f6dc700 R15: 0000000000000002
[   15.265720]  tcp_rcv_established+0x39a/0x890
[   15.266438] FS:  00007f65d9b5f700(0000) GS:ffff88807c400000(0000) knlGS:0000000000000000
[   15.267283]  ? __schedule+0x3fa/0x880
[   15.267287]  tcp_v4_do_rcv+0xb9/0x270
[   15.267290]  __release_sock+0x8a/0x160
[   15.268049] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   15.268788]  release_sock+0x32/0xd0
[   15.268791]  __inet_stream_connect+0x1d2/0x400
[   15.268795]  ? do_wait_intr_irq+0x80/0x80
[   15.269593] CR2: 0000000000223b10 CR3: 000000000b883000 CR4: 00000000000006f0
[   15.270246]  inet_stream_connect+0x36/0x50
[   15.270250]  mptcp_stream_connect+0x69/0x1b0
[   15.270253]  __sys_connect+0x122/0x140
[   15.271097] Kernel panic - not syncing: Fatal exception
[   15.271820]  ? syscall_enter_from_user_mode+0x17/0x50
[   15.283542]  ? lockdep_hardirqs_on_prepare+0xd4/0x170
[   15.284275]  __x64_sys_connect+0x1a/0x20
[   15.284853]  do_syscall_64+0x33/0x40
[   15.285369]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   15.286105] RIP: 0033:0x7fae49f19469
[   15.286638] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ff 49 2b 00 f7 d8 64 89 01 48
[   15.289295] RSP: 002b:00007fae4a609da8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
[   15.290375] RAX: ffffffffffffffda RBX: 000000000049bf00 RCX: 00007fae49f19469
[   15.291403] RDX: 0000000000000010 RSI: 00000000200000c0 RDI: 0000000000000005
[   15.292437] RBP: 000000000049bf00 R08: 0000000000000000 R09: 0000000000000000
[   15.293456] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049bf0c
[   15.294473] R13: 00007fff0004b6bf R14: 00007fae4a5ea000 R15: 0000000000000003
[   15.295492] Modules linked in:
[   15.295944] CR2: 0000000000000048
[   15.296567] Kernel Offset: disabled
[   15.296941] ---[ end Kernel panic - not syncing: Fatal exception ]---
Reported-by: NChristoph Paasch <cpaasch@apple.com>
Fixes: 84dfe367 (mptcp: send out dedicated ADD_ADDR packet)
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Link: https://lore.kernel.org/r/ccca4e8f01457a1b495c5d612ed16c5f7a585706.1608010058.git.geliangtang@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

parse the MPTCP FASTCLOSE subtype.

If provided key matches the local one, schedule the work queue to close
(with tcp reset) all subflows.

The MPTCP socket moves to closed state immediately.
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Christoph reported the following splat:

WARNING: CPU: 0 PID: 4615 at net/ipv4/inet_connection_sock.c:1031 inet_csk_listen_stop+0x8e8/0xad0 net/ipv4/inet_connection_sock.c:1031
Modules linked in:
CPU: 0 PID: 4615 Comm: syz-executor.4 Not tainted 5.9.0 #37
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:inet_csk_listen_stop+0x8e8/0xad0 net/ipv4/inet_connection_sock.c:1031
Code: 03 00 00 00 e8 79 b2 3d ff e9 ad f9 ff ff e8 1f 76 ba fe be 02 00 00 00 4c 89 f7 e8 62 b2 3d ff e9 14 f9 ff ff e8 08 76 ba fe <0f> 0b e9 97 f8 ff ff e8 fc 75 ba fe be 03 00 00 00 4c 89 f7 e8 3f
RSP: 0018:ffffc900037f7948 EFLAGS: 00010293
RAX: ffff88810a349c80 RBX: ffff888114ee1b00 RCX: ffffffff827b14cd
RDX: 0000000000000000 RSI: ffffffff827b1c38 RDI: 0000000000000005
RBP: ffff88810a2a8000 R08: ffff88810a349c80 R09: fffff520006fef1f
R10: 0000000000000003 R11: fffff520006fef1e R12: ffff888114ee2d00
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff888114ee1d68
FS:  00007f2ac1945700(0000) GS:ffff88811b400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd44798bc0 CR3: 0000000109810002 CR4: 0000000000170ef0
Call Trace:
 __tcp_close+0xd86/0x1110 net/ipv4/tcp.c:2433
 __mptcp_close_ssk+0x256/0x430 net/mptcp/protocol.c:1761
 __mptcp_destroy_sock+0x49b/0x770 net/mptcp/protocol.c:2127
 mptcp_close+0x62d/0x910 net/mptcp/protocol.c:2184
 inet_release+0xe9/0x1f0 net/ipv4/af_inet.c:434
 __sock_release+0xd2/0x280 net/socket.c:596
 sock_close+0x15/0x20 net/socket.c:1277
 __fput+0x276/0x960 fs/file_table.c:281
 task_work_run+0x109/0x1d0 kernel/task_work.c:151
 get_signal+0xe8f/0x1d40 kernel/signal.c:2561
 arch_do_signal+0x88/0x1b60 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0x9b/0xf0 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x22/0x150 kernel/entry/common.c:266
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f2ac1254469
Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ff 49 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007f2ac1944dc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffbf RBX: 000000000069bf00 RCX: 00007f2ac1254469
RDX: 0000000000000000 RSI: 0000000000008982 RDI: 0000000000000003
RBP: 000000000069bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000069bf0c
R13: 00007ffeb53f178f R14: 00000000004668b0 R15: 0000000000000003

After commit 0397c6d8 ("mptcp: keep unaccepted MPC subflow into
join list"), the msk's workqueue and/or PM can touch the MPC
subflow - and acquire its socket lock - even if it's still unaccepted.

If the above event races with the relevant listener socket close, we
can end-up with the above splat.

This change addresses the issue delaying the MPC socket insertion
in conn_list at accept time - that is, partially reverting the
blamed commit.

We must additionally ensure that mptcp_pm_fully_established()
happens after accept() time, or the PM will not be able to
handle properly such event - conn_list could be empty otherwise.

In the receive path, we check the subflow list node to ensure
it is out of the listener queue. Be sure client subflows do
not match transiently such condition moving them into the join
list earlier at creation time.

Since we now have multiple mptcp_pm_fully_established() call sites
from different code-paths, said helper can now race with itself.
Use an additional PM status bit to avoid multiple notifications.
Reported-by: NChristoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/103
Fixes: 0397c6d8 ("mptcp: keep unaccepted MPC subflow into join list"),
Reviewed-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch printed out more debugging information for the ADD_ADDR
suboption parsing on the incoming path.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The process is similar to that of the ADD_ADDR IPv6, this patch also sent
out a pure ack for the ADD_ADDR using port.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added a new add_addr_signal type named MPTCP_ADD_ADDR_PORT,
to identify it is an address with port to be added.

It also added a new parameter 'port' for both mptcp_add_addr_len and
mptcp_pm_add_addr_signal.

In mptcp_established_options_add_addr, we check whether the announced
address is added with port. If it is, we put this port number to
mptcp_out_options's port field.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In rfc8684, the length of ADD_ADDR suboption with IPv4 address and port
is 18 octets, but mptcp_write_options is 32-bit aligned, so we need to
pad it to 20 octets. All the other port related option lengths need to
be added up 2 octets similarly.

This patch added a new field 'port' in mptcp_out_options. When this
field is set with a port number, we need to add up 4 octets for the
ADD_ADDR suboption, and put the port number into the suboption.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The length of ADD_ADDR6 is 12 octets longer than ADD_ADDR. That's the
only difference between them.

This patch dropped the duplicate code between ADD_ADDR and ADD_ADDR6
suboptions writing, and unify them into one.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are two differences between ADD_ADDR suboption and ADD_ADDR echo
suboption: The length of the former is 8 octets longer than the length
of the latter. The former's echo-flag is 0, and latter's echo-flag is 1.

This patch added two local variables, len and echo, to unify ADD_ADDR
and ADD_ADDR echo suboptions writing.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We have some tasks triggered by the subflow receive path
which require to access the msk socket status, specifically:
mptcp_clean_una() and mptcp_push_pending()

We have almost everything in place to defer to the msk
release_cb such tasks when the msk sock is owned.

Since the worker is no more used to clean the acked data,
for fallback sockets we need to explicitly flush them.

As an added bonus we can move the wake-up code in __mptcp_clean_una(),
simplify a lot mptcp_poll() and move the timer update under
the data lock.

The worker is now used only to process and send DATA_FIN
packets and do the mptcp-level retransmissions.
Acked-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Extending the data_lock scope in mptcp_incoming_option
we can use that to protect both snd_una and wnd_end.
In the typical case, we will have a single atomic op instead of 2
Acked-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Send timely MPTCP-level ack is somewhat difficult when
the insertion into the msk receive level is performed
by the worker.

It needs TCP-level dup-ack to notify the MPTCP-level
ack_seq increase, as both the TCP-level ack seq and the
rcv window are unchanged.

We can actually avoid processing incoming data with the
worker, and let the subflow or recevmsg() send ack as needed.

When recvmsg() moves the skbs inside the msk receive queue,
the msk space is still unchanged, so tcp_cleanup_rbuf() could
end-up skipping TCP-level ack generation. Anyway, when
__mptcp_move_skbs() is invoked, a known amount of bytes is
going to be consumed soon: we update rcv wnd computation taking
them in account.

Additionally we need to explicitly trigger tcp_cleanup_rbuf()
when recvmsg() consumes a significant amount of the receive buffer.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

OoO handling attempts to detect when packet is out-of-window by testing
current ack sequence and remaining space vs. sequence number.

This doesn't work reliably. Store the highest allowed sequence number
that we've announced and use it to detect oow packets.

Do this when mptcp options get written to the packet (wire format).
For this to work we need to move the write_options call until after
stack selected a new tcp window.
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>