mptcp: add new sock flag to deal with join subflows

MP_JOIN subflows must not land into the accept queue.
Currently tcp_check_req() calls an mptcp specific helper
to detect such scen

mptcp: add new sock flag to deal with join subflows

MP_JOIN subflows must not land into the accept queue.
Currently tcp_check_req() calls an mptcp specific helper
to detect such scenario.

Such helper leverages the subflow context to check for
MP_JOIN subflows. We need to deal also with MP JOIN
failures, even when the subflow context is not available
due allocation failure.

A possible solution would be changing the syn_recv_sock()
signature to allow returning a more descriptive action/
error code and deal with that in tcp_check_req().

Since the above need is MPTCP specific, this patch instead
uses a TCP request socket hole to add a MPTCP specific flag.
Such flag is used by the MPTCP syn_recv_sock() to tell
tcp_check_req() how to deal with the request socket.

This change is a no-op for !MPTCP build, and makes the
MPTCP code simpler. It allows also the next patch to deal
correctly with MP JOIN failure.

v1 -> v2:
- be more conservative on drop_req initialization (Mat)

RFC -> v1:
- move the drop_req bit inside tcp_request_sock (Eric)

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Conflicts were all overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>

mptcp: move option parsing into mptcp_incoming_options()

The mptcp_options_received structure carries several per
packet flags (mp_capable, mp_join, etc.). Such fields must
be cleare

mptcp: move option parsing into mptcp_incoming_options()

The mptcp_options_received structure carries several per
packet flags (mp_capable, mp_join, etc.). Such fields must
be cleared on each packet, even on dropped ones or packet
not carrying any MPTCP options, but the current mptcp
code clears them only on TCP option reset.

On several races/corner cases we end-up with stray bits in
incoming options, leading to WARN_ON splats. e.g.:

[ 171.164906] Bad mapping: ssn=32714 map_seq=1 map_data_len=32713
[ 171.165006] WARNING: CPU: 1 PID: 5026 at net/mptcp/subflow.c:533 warn_bad_map (linux-mptcp/net/mptcp/subflow.c:533 linux-mptcp/net/mptcp/subflow.c:531)
[ 171.167632] Modules linked in: ip6_vti ip_vti ip_gre ipip sit tunnel4 ip_tunnel geneve ip6_udp_tunnel udp_tunnel macsec macvtap tap ipvlan macvlan 8021q garp mrp xfrm_interface veth netdevsim nlmon dummy team bonding vcan bridge stp llc ip6_gre gre ip6_tunnel tunnel6 tun binfmt_misc intel_rapl_msr intel_rapl_common rfkill kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel joydev virtio_balloon pcspkr i2c_piix4 sunrpc ip_tables xfs libcrc32c crc32c_intel serio_raw virtio_console ata_generic virtio_blk virtio_net net_failover failover ata_piix libata
[ 171.199464] CPU: 1 PID: 5026 Comm: repro Not tainted 5.7.0-rc1.mptcp_f227fdf5d388+ #95
[ 171.200886] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
[ 171.202546] RIP: 0010:warn_bad_map (linux-mptcp/net/mptcp/subflow.c:533 linux-mptcp/net/mptcp/subflow.c:531)
[ 171.206537] Code: c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1d 8b 55 3c 44 89 e6 48 c7 c7 20 51 13 95 e8 37 8b 22 fe <0f> 0b 48 83 c4 08 5b 5d 41 5c c3 89 4c 24 04 e8 db d6 94 fe 8b 4c
[ 171.220473] RSP: 0018:ffffc90000150560 EFLAGS: 00010282
[ 171.221639] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 171.223108] RDX: 0000000000000000 RSI: 0000000000000008 RDI: fffff5200002a09e
[ 171.224388] RBP: ffff8880aa6e3c00 R08: 0000000000000001 R09: fffffbfff2ec9955
[ 171.225706] R10: ffffffff9764caa7 R11: fffffbfff2ec9954 R12: 0000000000007fca
[ 171.227211] R13: ffff8881066f4a7f R14: ffff8880aa6e3c00 R15: 0000000000000020
[ 171.228460] FS: 00007f8623719740(0000) GS:ffff88810be00000(0000) knlGS:0000000000000000
[ 171.230065] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 171.231303] CR2: 00007ffdab190a50 CR3: 00000001038ea006 CR4: 0000000000160ee0
[ 171.232586] Call Trace:
[ 171.233109] <IRQ>
[ 171.233531] get_mapping_status (linux-mptcp/net/mptcp/subflow.c:691)
[ 171.234371] mptcp_subflow_data_available (linux-mptcp/net/mptcp/subflow.c:736 linux-mptcp/net/mptcp/subflow.c:832)
[ 171.238181] subflow_state_change (linux-mptcp/net/mptcp/subflow.c:1085 (discriminator 1))
[ 171.239066] tcp_fin (linux-mptcp/net/ipv4/tcp_input.c:4217)
[ 171.240123] tcp_data_queue (linux-mptcp/./include/linux/compiler.h:199 linux-mptcp/net/ipv4/tcp_input.c:4822)
[ 171.245083] tcp_rcv_established (linux-mptcp/./include/linux/skbuff.h:1785 linux-mptcp/./include/net/tcp.h:1774 linux-mptcp/./include/net/tcp.h:1847 linux-mptcp/net/ipv4/tcp_input.c:5238 linux-mptcp/net/ipv4/tcp_input.c:5730)
[ 171.254089] tcp_v4_rcv (linux-mptcp/./include/linux/spinlock.h:393 linux-mptcp/net/ipv4/tcp_ipv4.c:2009)
[ 171.258969] ip_protocol_deliver_rcu (linux-mptcp/net/ipv4/ip_input.c:204 (discriminator 1))
[ 171.260214] ip_local_deliver_finish (linux-mptcp/./include/linux/rcupdate.h:651 linux-mptcp/net/ipv4/ip_input.c:232)
[ 171.261389] ip_local_deliver (linux-mptcp/./include/linux/netfilter.h:307 linux-mptcp/./include/linux/netfilter.h:301 linux-mptcp/net/ipv4/ip_input.c:252)
[ 171.265884] ip_rcv (linux-mptcp/./include/linux/netfilter.h:307 linux-mptcp/./include/linux/netfilter.h:301 linux-mptcp/net/ipv4/ip_input.c:539)
[ 171.273666] process_backlog (linux-mptcp/./include/linux/rcupdate.h:651 linux-mptcp/net/core/dev.c:6135)
[ 171.275328] net_rx_action (linux-mptcp/net/core/dev.c:6572 linux-mptcp/net/core/dev.c:6640)
[ 171.280472] __do_softirq (linux-mptcp/./arch/x86/include/asm/jump_label.h:25 linux-mptcp/./include/linux/jump_label.h:200 linux-mptcp/./include/trace/events/irq.h:142 linux-mptcp/kernel/softirq.c:293)
[ 171.281379] do_softirq_own_stack (linux-mptcp/arch/x86/entry/entry_64.S:1083)
[ 171.282358] </IRQ>

We could address the issue clearing explicitly the relevant fields
in several places - tcp_parse_option, tcp_fast_parse_options,
possibly others.

Instead we move the MPTCP option parsing into the already existing
mptcp ingress hook, so that we need to clear the fields in a single
place.

This allows us dropping an MPTCP hook from the TCP code and
removing the quite large mptcp_options_received from the tcp_sock
struct. On the flip side, the MPTCP sockets will traverse the
option space twice (in tcp_parse_option() and in
mptcp_incoming_options(). That looks acceptable: we already
do that for syn and 3rd ack packets, plain TCP socket will
benefit from it, and even MPTCP sockets will experience better
code locality, reducing the jumps between TCP and MPTCP code.

v1 -> v2:
- rebased on current '-net' tree

Fixes: 648ef4b88673 ("mptcp: Implement MPTCP receive path")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

mptcp: consolidate synack processing.

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

mptcp: consolidate synack processing.

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>

show more ...

tcp: mptcp: use mptcp receive buffer space to select rcv window

In MPTCP, the receive window is shared across all subflows, because it
refers to the mptcp-level sequence space.

tcp: mptcp: use mptcp receive buffer space to select rcv window

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>

show more ...

mptcp: add and use MIB counter infrastructure

Exported via same /proc file as the Linux TCP MIB counters, so "netstat -s"
or "nstat" will show them automatically.

The MPTCP MIB

mptcp: add and use MIB counter infrastructure

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>

show more ...

mptcp: Add handling of outgoing MP_JOIN requests

Subflow creation may be initiated by the path manager when
the primary connection is fully established and a remote
address has been

mptcp: Add handling of outgoing MP_JOIN requests

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>

show more ...

mptcp: Add handling of incoming MP_JOIN requests

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: Add handling of incoming MP_JOIN requests

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>

show more ...

mptcp: Add ADD_ADDR handling

Add handling for sending and receiving the ADD_ADDR, ADD_ADDR6,
and RM_ADDR suboptions.

Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.n

mptcp: Add ADD_ADDR handling

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>

show more ...

mptcp: Fix undefined mptcp_handle_ipv6_mapped for modular IPV6

If CONFIG_MPTCP=y, CONFIG_MPTCP_IPV6=n, and CONFIG_IPV6=m:

ERROR: "mptcp_handle_ipv6_mapped" [net/ipv6/ipv6.ko] un

mptcp: Fix undefined mptcp_handle_ipv6_mapped for modular IPV6

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: cec37a6e41aae7bf ("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>

show more ...

mptcp: parse and emit MP_CAPABLE option according to v1 spec

This implements MP_CAPABLE options parsing and writing according
to RFC 6824 bis / RFC 8684: MPTCP v1.

Local key is

mptcp: parse and emit MP_CAPABLE option according to v1 spec

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>

show more ...

mptcp: Implement MPTCP receive path

Parses incoming DSS options and populates outgoing MPTCP ACK
fields. MPTCP fields are parsed from the TCP option header and placed in
an skb exten

mptcp: Implement MPTCP receive path

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>

show more ...

mptcp: Write MPTCP DSS headers to outgoing data packets

Per-packet metadata required to write the MPTCP DSS option is written to
the skb_ext area. One write to the socket may contain mor

mptcp: Write MPTCP DSS headers to outgoing data packets

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>

show more ...

mptcp: Handle MP_CAPABLE options for outgoing connections

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 ad

mptcp: Handle MP_CAPABLE options for outgoing connections

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>

show more ...

mptcp: Handle MPTCP TCP options

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 (R

mptcp: Handle MPTCP TCP options

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>

show more ...

mptcp: Add MPTCP socket stubs

Implements the infrastructure for MPTCP sockets.

MPTCP sockets open one in-kernel TCP socket per subflow. These subflow
sockets are only managed by

mptcp: Add MPTCP socket stubs

Implements the infrastructure for MPTCP sockets.

MPTCP sockets open one in-kernel TCP socket per subflow. These subflow
sockets are only managed by the MPTCP socket that owns them and are not
visible from userspace. This commit allows a userspace program to open
an MPTCP socket with:

sock = socket(AF_INET, SOCK_STREAM, IPPROTO_MPTCP);

The resulting socket is simply a wrapper around a single regular TCP
socket, without any of the MPTCP protocol implemented over the wire.

Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com>
Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com>
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: 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>

show more ...

tcp: coalesce/collapse must respect MPTCP extensions

Coalesce and collapse of packets carrying MPTCP extensions is allowed
when the newer packet has no extension or the extensions carrie

tcp: coalesce/collapse must respect MPTCP extensions

Coalesce and collapse of packets carrying MPTCP extensions is allowed
when the newer packet has no extension or the extensions carried by both
packets are equal.

This allows merging of TSO packet trains and even cross-TSO packets, and
does not require any additional action when moving data into existing
SKBs.

v3 -> v4:
- allow collapsing, under mptcp_skb_can_collapse() constraint

v5 -> v6:
- clarify MPTCP skb extensions must always be cleared at allocation
time

Co-developed-by: Paolo Abeni <pabeni@redhat.com>
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>

show more ...

mptcp: Add MPTCP to skb extensions

Add enum value for MPTCP and update config dependencies

v5 -> v6:
- fixed '__unused' field size

Co-developed-by: Matthieu Baerts <ma

mptcp: Add MPTCP to skb extensions

Add enum value for MPTCP and update config dependencies

v5 -> v6:
- fixed '__unused' field size

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: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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