RFC8684 allows to send 32-bit DATA_ACKs as long as the peer is not
sending 64-bit data-sequence numbers. The 64-bit DSN is only there for
extreme scenarios when a very high throughput subflow is combined with a
long-RTT subflow such that the high-throughput subflow wraps around the
32-bit sequence number space within an RTT of the high-RTT subflow.
It is thus a rare scenario and we should try to use the 32-bit DATA_ACK
instead as long as possible. It allows to reduce the TCP-option overhead
by 4 bytes, thus makes space for an additional SACK-block. It also makes
tcpdumps much easier to read when the DSN and DATA_ACK are both either
32 or 64-bit.
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
When parsing MPC+data packets we set the dss field, so
we must also initialize the data_fin, or we can find stray
value there.
Fixes: 9a19371bf0 ("mptcp: fix data_fin handing in RX path")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The mentioned RX option field is initialized only for DSS
packet, we must access it only if 'dss' is set too, or
the subflow will end-up in a bad status, leading to
RFC violations.
Fixes: d22f4988ff ("mptcp: process MP_CAPABLE data option")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Syzcaller has found a way to trigger the WARN_ON_ONCE condition
in check_fully_established().
The root cause is a legit fallback to TCP scenario, so replace
the WARN with a plain message on a more strict condition.
Fixes: f296234c98 ("mptcp: Add handling of incoming MP_JOIN requests")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently the MPTCP code uses 2 hooks to process syn-ack
packets, mptcp_rcv_synsent() and the sk_rx_dst_set()
callback.
We can drop the first, moving the relevant code into the
latter, reducing the hooking into the TCP code. This is
also needed by the next patch.
v1 -> v2:
- use local tcp sock ptr instead of casting the sk variable
several times - DaveM
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The data fin flag is set only via a DSS option, but
mptcp_incoming_options() copies it unconditionally from the
provided RX options.
Since we do not clear all the mptcp sock RX options in a
socket free/alloc cycle, we can end-up with a stray data_fin
value while parsing e.g. MPC packets.
That would lead to mapping data corruption and will trigger
a few WARN_ON() in the RX path.
Instead of adding a costly memset(), fetch the data_fin flag
only for DSS packets - when we always explicitly initialize
such bit at option parsing time.
Fixes: 648ef4b886 ("mptcp: Implement MPTCP receive path")
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The timer will be used to schedule retransmission. It's
frequency is based on the current subflow RTO estimation and
is reset on every una_seq update
The timer is clearer for good by __mptcp_clear_xmit()
Also clean MPTCP rtx queue before each transmission.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
So that we keep per unacked sequence number consistent; since
we update per msk data, use an atomic64 cmpxchg() to protect
against concurrent updates from multiple subflows.
Initialize the snd_una at connect()/accept() time.
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Subflow creation may be initiated by the path manager when
the primary connection is fully established and a remote
address has been received via ADD_ADDR.
Create an in-kernel sock and use kernel_connect() to
initiate connection.
Passive sockets can't acquire the mptcp socket lock at
subflow creation time, so an additional list protected by
a new spinlock is used to track the MPJ subflows.
Such list is spliced into conn_list tail every time the msk
socket lock is acquired, so that it will not interfere
with data flow on the original connection.
Data flow and connection failover not addressed by this commit.
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Process the MP_JOIN option in a SYN packet with the same flow
as MP_CAPABLE but when the third ACK is received add the
subflow to the MPTCP socket subflow list instead of adding it to
the TCP socket accept queue.
The subflow is added at the end of the subflow list so it will not
interfere with the existing subflows operation and no data is
expected to be transmitted on it.
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add enough of a path manager interface to allow sending of ADD_ADDR
when an incoming MPTCP connection is created. Capable of sending only
a single IPv4 ADD_ADDR option. The 'pm_data' element of the connection
sock will need to be expanded to handle multiple interfaces and IPv6.
Partial processing of the incoming ADD_ADDR is included so the path
manager notification of that event happens at the proper time, which
involves validating the incoming address information.
This is a skeleton interface definition for events generated by
MPTCP.
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add handling for sending and receiving the ADD_ADDR, ADD_ADDR6,
and RM_ADDR suboptions.
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixes gcc '-Wunused-but-set-variable' warning:
net/mptcp/options.c: In function 'mptcp_established_options_dss':
net/mptcp/options.c:338:7: warning:
variable 'can_ack' set but not used [-Wunused-but-set-variable]
commit dc093db5cc ("mptcp: drop unneeded checks")
leave behind this unused, remove it.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The name is misleading, it actually tracks the 'fully established'
status.
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After the previous patch subflow->conn is always != NULL and
is never changed. We can drop a bunch of now unneeded checks.
v1 -> v2:
- rebased on top of commit 2398e3991b ("mptcp: always
include dack if possible.")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently passive MPTCP socket can skip including the DACK
option - if the peer sends data before accept() completes.
The above happens because the msk 'can_ack' flag is set
only after the accept() call.
Such missing DACK option may cause - as per RFC spec -
unwanted fallback to TCP.
This change addresses the issue using the key material
available in the current subflow, if any, to create a suitable
dack option when msk ack seq is not yet available.
v1 -> v2:
- adavance the generated ack after the initial MPC packet
Fixes: d22f4988ff ("mptcp: process MP_CAPABLE data option")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When a DATA_FIN is sent in a MPTCP DSS option that contains a data
mapping, the DATA_FIN consumes one byte of space in the mapping. In this
case, the DATA_FIN should only be included in the DSS option if its
sequence number aligns with the end of the mapped data. Otherwise the
subflow can send an incorrect implicit sequence number for the DATA_FIN,
and the DATA_ACK for that sequence number would not close the
MPTCP-level connection correctly.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of reading the MPTCP-level sequence number when sending DATA_FIN,
store the data in the subflow so it can be safely accessed when the
subflow TCP headers are written to the packet without the MPTCP-level
lock held. This also allows the MPTCP-level socket to close individual
subflows without closing the MPTCP connection.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements the handling of MP_CAPABLE + data option, as per
RFC 6824 bis / RFC 8684: MPTCP v1.
On the server side we can receive the remote key after that the connection
is established. We need to explicitly track the 'missing remote key'
status and avoid emitting a mptcp ack until we get such info.
When a late/retransmitted/OoO pkt carrying MP_CAPABLE[+data] option
is received, we have to propagate the mptcp seq number info to
the msk socket. To avoid ABBA locking issue, explicitly check for
that in recvmsg(), where we own msk and subflow sock locks.
The above also means that an established mp_capable subflow - still
waiting for the remote key - can be 'downgraded' to plain TCP.
Such change could potentially block a reader waiting for new data
forever - as they hook to msk, while later wake-up after the downgrade
will be on subflow only.
The above issue is not handled here, we likely have to get rid of
msk->fallback to handle that cleanly.
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This implements MP_CAPABLE options parsing and writing according
to RFC 6824 bis / RFC 8684: MPTCP v1.
Local key is sent on syn/ack, and both keys are sent on 3rd ack.
MP_CAPABLE messages len are updated accordingly. We need the skbuff to
correctly emit the above, so we push the skbuff struct as an argument
all the way from tcp code to the relevant mptcp callbacks.
When processing incoming MP_CAPABLE + data, build a full blown DSS-like
map info, to simplify later processing. On child socket creation, we
need to record the remote key, if available.
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For simplicity's sake use directly sha256 primitives (and pull them
as a required build dep).
Add optional, boot-time self-tests for the hmac function.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Parses incoming DSS options and populates outgoing MPTCP ACK
fields. MPTCP fields are parsed from the TCP option header and placed in
an skb extension, allowing the upper MPTCP layer to access MPTCP
options after the skb has gone through the TCP stack.
The subflow implements its own data_ready() ops, which ensures that the
pending data is in sequence - according to MPTCP seq number - dropping
out-of-seq skbs. The DATA_READY bit flag is set if this is the case.
This allows the MPTCP socket layer to determine if more data is
available without having to consult the individual subflows.
It additionally validates the current mapping and propagates EoF events
to the connection socket.
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Co-developed-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Per-packet metadata required to write the MPTCP DSS option is written to
the skb_ext area. One write to the socket may contain more than one
packet of data, which is copied to page fragments and mapped in to MPTCP
DSS segments with size determined by the available page fragments and
the maximum mapping length allowed by the MPTCP specification. If
do_tcp_sendpages() splits a DSS segment in to multiple skbs, that's ok -
the later skbs can either have duplicated DSS mapping information or
none at all, and the receiver can handle that.
The current implementation uses the subflow frag cache and tcp
sendpages to avoid excessive code duplication. More work is required to
ensure that it works correctly under memory pressure and to support
MPTCP-level retransmissions.
The MPTCP DSS checksum is not yet implemented.
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add hooks to tcp_output.c to add MP_CAPABLE to an outgoing SYN request,
to capture the MP_CAPABLE in the received SYN-ACK, to add MP_CAPABLE to
the final ACK of the three-way handshake.
Use the .sk_rx_dst_set() handler in the subflow proto to capture when the
responding SYN-ACK is received and notify the MPTCP connection layer.
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add hooks to parse and format the MP_CAPABLE option.
This option is handled according to MPTCP version 0 (RFC6824).
MPTCP version 1 MP_CAPABLE (RFC6824bis/RFC8684) will be added later in
coordination with related code changes.
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
