In MPTCP, the receive window is shared across all subflows, because it
refers to the mptcp-level sequence space.
MPTCP receivers already place incoming packets on the mptcp socket
receive queue and will charge it to the mptcp socket rcvbuf until
userspace consumes the data.
Update __tcp_select_window to use the occupancy of the parent/mptcp
socket instead of the subflow socket in case the tcp socket is part
of a logical mptcp connection.
This commit doesn't change choice of initial window for passive or active
connections.
While it would be possible to change those as well, this adds complexity
(especially when handling MP_JOIN requests). Furthermore, the MPTCP RFC
specifically says that a MPTCP sender 'MUST NOT use the RCV.WND field
of a TCP segment at the connection level if it does not also carry a DSS
option with a Data ACK field.'
SYN/SYNACK packets do not carry a DSS option with a Data ACK field.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
We don't need them, as we can use the current ingress opt
data instead. Setting them in syn_recv_sock() may causes
inconsistent mptcp socket status, as per previous commit.
Fixes: cc7972ea19 ("mptcp: parse and emit MP_CAPABLE option according to v1 spec")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If multiple CPUs races on the same req_sock in syn_recv_sock(),
flipping such field can cause inconsistent child socket status.
When racing, the CPU losing the req ownership may still change
the mptcp request socket mp_capable flag while the CPU owning
the request is cloning the socket, leaving the child socket with
'is_mptcp' set but no 'mp_capable' flag.
Such socket will stay with 'conn' field cleared, heading to oops
in later mptcp callback.
Address the issue tracking the fallback status in a local variable.
Fixes: 58b0991962 ("mptcp: create msk early")
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: David S. Miller <davem@davemloft.net>
We need to set sk_state to CLOSED, else we will get following:
IPv4: Attempt to release TCP socket in state 3 00000000b95f109e
IPv4: Attempt to release TCP socket in state 10 00000000b95f109e
First one is from inet_sock_destruct(), second one from
mptcp_sk_clone failure handling. Setting sk_state to CLOSED isn't
enough, we also need to orphan sk so it has DEAD flag set.
Otherwise, a very similar warning is printed from inet_sock_destruct().
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Following snippet (replicated from syzkaller reproducer) generates
warning: "IPv4: Attempt to release TCP socket in state 1".
int main(void) {
struct sockaddr_in sin1 = { .sin_family = 2, .sin_port = 0x4e20,
.sin_addr.s_addr = 0x010000e0, };
struct sockaddr_in sin2 = { .sin_family = 2,
.sin_addr.s_addr = 0x0100007f, };
struct sockaddr_in sin3 = { .sin_family = 2, .sin_port = 0x4e20,
.sin_addr.s_addr = 0x0100007f, };
int r0 = socket(0x2, 0x1, 0x106);
int r1 = socket(0x2, 0x1, 0x106);
bind(r1, (void *)&sin1, sizeof(sin1));
connect(r1, (void *)&sin2, sizeof(sin2));
listen(r1, 3);
return connect(r0, (void *)&sin3, 0x4d);
}
Reason is that the newly generated mptcp socket is closed via the ulp
release of the tcp listener socket when its accept backlog gets purged.
To fix this, delay setting the ESTABLISHED state until after userspace
calls accept and via mptcp specific destructor.
Fixes: 58b0991962 ("mptcp: create msk early")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/9
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is needed at least until proper MPTCP-Level fin/reset
signalling gets added:
We wake parent when a subflow changes, but we should do this only
when all subflows have closed, not just one.
Schedule the mptcp worker and tell it to check eof state on all
subflows.
Only flag mptcp socket as closed and wake userspace processes blocking
in poll if all subflows have closed.
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Exported via same /proc file as the Linux TCP MIB counters, so "netstat -s"
or "nstat" will show them automatically.
The MPTCP MIB counters are allocated in a distinct pcpu area in order to
avoid bloating/wasting TCP pcpu memory.
Counters are allocated once the first MPTCP socket is created in a
network namespace and free'd on exit.
If no sockets have been allocated, all-zero mptcp counters are shown.
The MIB counter list is taken from the multipath-tcp.org kernel, but
only a few counters have been picked up so far. The counter list can
be increased at any time later on.
v2 -> v3:
- remove 'inline' in foo.c files (David S. Miller)
Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
add ulp-specific diagnostic functions, so that subflow information can be
dumped to userspace programs like 'ss'.
v2 -> v3:
- uapi: use bit macros appropriate for userspace
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: Davide Caratti <dcaratti@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>
it's still possible for packetdrill to hang in mptcp_sendmsg(), when the
MPTCP socket falls back to regular TCP (e.g. after receiving unsupported
flags/version during the three-way handshake). Adjust MPTCP socket state
earlier, to ensure correct functionality of mptcp_sendmsg() even in case
of TCP fallback.
Fixes: 767d3ded5f ("net: mptcp: don't hang before sending 'MP capable with data'")
Fixes: 1954b86016 ("mptcp: Check connection state before attempting send")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
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 commit 58b0991962 ("mptcp: create msk early"), the
msk socket is already available at subflow_syn_recv_sock()
time. Let's move there the state update, to mirror more
closely the first subflow state.
The above will also help multiple subflow supports.
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>
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>
This change moves the mptcp socket allocation from mptcp_accept() to
subflow_syn_recv_sock(), so that subflow->conn is now always set
for the non fallback scenario.
It allows cleaning up a bit mptcp_accept() reducing the additional
locking and will allow fourther cleanup in the next patch.
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>
We can't lock_sock() the mptcp socket from the subflow data_ready callback,
it would result in ABBA deadlock with the subflow socket lock.
We can however grab the spinlock: if that succeeds and the mptcp socket
is not owned at the moment, we can process the new skbs right away
without deferring this to the work queue.
This avoids the schedule_work and hence the small delay until the
work item is processed.
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Only used to discard stale data from the subflow, so move
it where needed.
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
allows us to schedule the work queue to drain the ssk receive queue in
a followup patch.
This is needed to avoid sending all-to-pessimistic mptcp-level
acknowledgements. At this time, the ack_seq is what was last read by
userspace instead of the highest in-sequence number queued for reading.
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If CONFIG_MPTCP=y, CONFIG_MPTCP_IPV6=n, and CONFIG_IPV6=m:
ERROR: "mptcp_handle_ipv6_mapped" [net/ipv6/ipv6.ko] undefined!
This does not happen if CONFIG_MPTCP_IPV6=y, as CONFIG_MPTCP_IPV6
selects CONFIG_IPV6, and thus forces CONFIG_IPV6 builtin.
As exporting a symbol for an empty function would be a bit wasteful, fix
this by providing a dummy version of mptcp_handle_ipv6_mapped() for the
CONFIG_MPTCP_IPV6=n case.
Rename mptcp_handle_ipv6_mapped() to mptcpv6_handle_mapped(), to make it
clear this is a pure-IPV6 function, just like mptcpv6_init().
Fixes: cec37a6e41 ("mptcp: Handle MP_CAPABLE options for outgoing connections")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
We can't deal with syncookie mode yet, the syncookie rx path will create
tcp reqsk, i.e. we get OOB access because we treat tcp reqsk as mptcp reqsk one:
TCP: SYN flooding on port 20002. Sending cookies.
BUG: KASAN: slab-out-of-bounds in subflow_syn_recv_sock+0x451/0x4d0 net/mptcp/subflow.c:191
Read of size 1 at addr ffff8881167bc148 by task syz-executor099/2120
subflow_syn_recv_sock+0x451/0x4d0 net/mptcp/subflow.c:191
tcp_get_cookie_sock+0xcf/0x520 net/ipv4/syncookies.c:209
cookie_v6_check+0x15a5/0x1e90 net/ipv6/syncookies.c:252
tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1123 [inline]
[..]
Bug can be reproduced via "sysctl net.ipv4.tcp_syncookies=2".
Note that MPTCP should work with syncookies (4th ack would carry needed
state), but it appears better to sort that out in -next so do tcp
fallback for now.
I removed the MPTCP ifdef for tcp_rsk "is_mptcp" member because
if (IS_ENABLED()) is easier to read than "#ifdef IS_ENABLED()/#endif" pair.
Cc: Eric Dumazet <edumazet@google.com>
Fixes: cec37a6e41 ("mptcp: Handle MP_CAPABLE options for outgoing connections")
Reported-by: Christoph Paasch <cpaasch@apple.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/mptcp/subflow.c: In function ‘mptcp_subflow_create_socket’:
net/mptcp/subflow.c:624:25: error: ‘struct netns_core’ has no member named ‘sock_inuse’
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
checkpatch.pl had a few complaints in the last set of MPTCP patches:
ERROR: code indent should use tabs where possible
+^I subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped);$
CHECK: Comparison to NULL could be written "!new_ctx"
+ if (new_ctx == NULL) {
ERROR: "foo * bar" should be "foo *bar"
+static const struct proto_ops * tcp_proto_ops(struct sock *sk)
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>
Add new SEND_SPACE flag to indicate that a subflow has enough space to
accept more data for transmission.
It gets cleared at the end of mptcp_sendmsg() in case ssk has run
below the free watermark.
It is (re-set) from the wspace callback.
This allows us to use msk->flags to determine the poll mask.
Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
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>
Generate the local keys, IDSN, and token when creating a new socket.
Introduce the token tree to track all tokens in use using a radix tree
with the MPTCP token itself as the index.
Override the rebuild_header callback in inet_connection_sock_af_ops for
creating the local key on a new outgoing connection.
Override the init_req callback of tcp_request_sock_ops for creating the
local key on a new incoming connection.
Will be used to obtain the MPTCP parent socket to handle incoming joins.
Co-developed-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
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: 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>
Use ULP to associate a subflow_context structure with each TCP subflow
socket. Creating these sockets requires new bind and connect functions
to make sure ULP is set up immediately when the subflow sockets are
created.
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
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: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
