dccp: preserve const qualifier in dccp_sk()

We can change dccp_sk() to propagate its argument const qualifier,
thanks to container_of_const().

Signed-off-by: Eric Dumazet <[email protected]>
Revi

dccp: preserve const qualifier in dccp_sk()

We can change dccp_sk() to propagate its argument const qualifier,
thanks to container_of_const().

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: dccp: Replace zero-length array with flexible-array member

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare

net: dccp: Replace zero-length array with flexible-array member

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

dccp: fix use-after-free in dccp_feat_activate_values

Dmitry reported crashes in DCCP stack [1]

Problem here is that when I got rid of listener spinlock, I missed the
fact that DCCP stores a comple

dccp: fix use-after-free in dccp_feat_activate_values

Dmitry reported crashes in DCCP stack [1]

Problem here is that when I got rid of listener spinlock, I missed the
fact that DCCP stores a complex state in struct dccp_request_sock,
while TCP does not.

Since multiple cpus could access it at the same time, we need to add
protection.

[1]
BUG: KASAN: use-after-free in dccp_feat_activate_values+0x967/0xab0
net/dccp/feat.c:1541 at addr ffff88003713be68
Read of size 8 by task syz-executor2/8457
CPU: 2 PID: 8457 Comm: syz-executor2 Not tainted 4.10.0-rc7+ #127
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:15 [inline]
dump_stack+0x292/0x398 lib/dump_stack.c:51
kasan_object_err+0x1c/0x70 mm/kasan/report.c:162
print_address_description mm/kasan/report.c:200 [inline]
kasan_report_error mm/kasan/report.c:289 [inline]
kasan_report.part.1+0x20e/0x4e0 mm/kasan/report.c:311
kasan_report mm/kasan/report.c:332 [inline]
__asan_report_load8_noabort+0x29/0x30 mm/kasan/report.c:332
dccp_feat_activate_values+0x967/0xab0 net/dccp/feat.c:1541
dccp_create_openreq_child+0x464/0x610 net/dccp/minisocks.c:121
dccp_v6_request_recv_sock+0x1f6/0x1960 net/dccp/ipv6.c:457
dccp_check_req+0x335/0x5a0 net/dccp/minisocks.c:186
dccp_v6_rcv+0x69e/0x1d00 net/dccp/ipv6.c:711
ip6_input_finish+0x46d/0x17a0 net/ipv6/ip6_input.c:279
NF_HOOK include/linux/netfilter.h:257 [inline]
ip6_input+0xdb/0x590 net/ipv6/ip6_input.c:322
dst_input include/net/dst.h:507 [inline]
ip6_rcv_finish+0x289/0x890 net/ipv6/ip6_input.c:69
NF_HOOK include/linux/netfilter.h:257 [inline]
ipv6_rcv+0x12ec/0x23d0 net/ipv6/ip6_input.c:203
__netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190
__netif_receive_skb+0x2a/0x170 net/core/dev.c:4228
process_backlog+0xe5/0x6c0 net/core/dev.c:4839
napi_poll net/core/dev.c:5202 [inline]
net_rx_action+0xe70/0x1900 net/core/dev.c:5267
__do_softirq+0x2fb/0xb7d kernel/softirq.c:284
do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:902
</IRQ>
do_softirq.part.17+0x1e8/0x230 kernel/softirq.c:328
do_softirq kernel/softirq.c:176 [inline]
__local_bh_enable_ip+0x1f2/0x200 kernel/softirq.c:181
local_bh_enable include/linux/bottom_half.h:31 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:971 [inline]
ip6_finish_output2+0xbb0/0x23d0 net/ipv6/ip6_output.c:123
ip6_finish_output+0x302/0x960 net/ipv6/ip6_output.c:148
NF_HOOK_COND include/linux/netfilter.h:246 [inline]
ip6_output+0x1cb/0x8d0 net/ipv6/ip6_output.c:162
ip6_xmit+0xcdf/0x20d0 include/net/dst.h:501
inet6_csk_xmit+0x320/0x5f0 net/ipv6/inet6_connection_sock.c:179
dccp_transmit_skb+0xb09/0x1120 net/dccp/output.c:141
dccp_xmit_packet+0x215/0x760 net/dccp/output.c:280
dccp_write_xmit+0x168/0x1d0 net/dccp/output.c:362
dccp_sendmsg+0x79c/0xb10 net/dccp/proto.c:796
inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744
sock_sendmsg_nosec net/socket.c:635 [inline]
sock_sendmsg+0xca/0x110 net/socket.c:645
SYSC_sendto+0x660/0x810 net/socket.c:1687
SyS_sendto+0x40/0x50 net/socket.c:1655
entry_SYSCALL_64_fastpath+0x1f/0xc2
RIP: 0033:0x4458b9
RSP: 002b:00007f8ceb77bb58 EFLAGS: 00000282 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000017 RCX: 00000000004458b9
RDX: 0000000000000023 RSI: 0000000020e60000 RDI: 0000000000000017
RBP: 00000000006e1b90 R08: 00000000200f9fe1 R09: 0000000000000020
R10: 0000000000008010 R11: 0000000000000282 R12: 00000000007080a8
R13: 0000000000000000 R14: 00007f8ceb77c9c0 R15: 00007f8ceb77c700
Object at ffff88003713be50, in cache kmalloc-64 size: 64
Allocated:
PID = 8446
save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
save_stack+0x43/0xd0 mm/kasan/kasan.c:502
set_track mm/kasan/kasan.c:514 [inline]
kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:605
kmem_cache_alloc_trace+0x82/0x270 mm/slub.c:2738
kmalloc include/linux/slab.h:490 [inline]
dccp_feat_entry_new+0x214/0x410 net/dccp/feat.c:467
dccp_feat_push_change+0x38/0x220 net/dccp/feat.c:487
__feat_register_sp+0x223/0x2f0 net/dccp/feat.c:741
dccp_feat_propagate_ccid+0x22b/0x2b0 net/dccp/feat.c:949
dccp_feat_server_ccid_dependencies+0x1b3/0x250 net/dccp/feat.c:1012
dccp_make_response+0x1f1/0xc90 net/dccp/output.c:423
dccp_v6_send_response+0x4ec/0xc20 net/dccp/ipv6.c:217
dccp_v6_conn_request+0xaba/0x11b0 net/dccp/ipv6.c:377
dccp_rcv_state_process+0x51e/0x1650 net/dccp/input.c:606
dccp_v6_do_rcv+0x213/0x350 net/dccp/ipv6.c:632
sk_backlog_rcv include/net/sock.h:893 [inline]
__sk_receive_skb+0x36f/0xcc0 net/core/sock.c:479
dccp_v6_rcv+0xba5/0x1d00 net/dccp/ipv6.c:742
ip6_input_finish+0x46d/0x17a0 net/ipv6/ip6_input.c:279
NF_HOOK include/linux/netfilter.h:257 [inline]
ip6_input+0xdb/0x590 net/ipv6/ip6_input.c:322
dst_input include/net/dst.h:507 [inline]
ip6_rcv_finish+0x289/0x890 net/ipv6/ip6_input.c:69
NF_HOOK include/linux/netfilter.h:257 [inline]
ipv6_rcv+0x12ec/0x23d0 net/ipv6/ip6_input.c:203
__netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190
__netif_receive_skb+0x2a/0x170 net/core/dev.c:4228
process_backlog+0xe5/0x6c0 net/core/dev.c:4839
napi_poll net/core/dev.c:5202 [inline]
net_rx_action+0xe70/0x1900 net/core/dev.c:5267
__do_softirq+0x2fb/0xb7d kernel/softirq.c:284
Freed:
PID = 15
save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
save_stack+0x43/0xd0 mm/kasan/kasan.c:502
set_track mm/kasan/kasan.c:514 [inline]
kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:578
slab_free_hook mm/slub.c:1355 [inline]
slab_free_freelist_hook mm/slub.c:1377 [inline]
slab_free mm/slub.c:2954 [inline]
kfree+0xe8/0x2b0 mm/slub.c:3874
dccp_feat_entry_destructor.part.4+0x48/0x60 net/dccp/feat.c:418
dccp_feat_entry_destructor net/dccp/feat.c:416 [inline]
dccp_feat_list_pop net/dccp/feat.c:541 [inline]
dccp_feat_activate_values+0x57f/0xab0 net/dccp/feat.c:1543
dccp_create_openreq_child+0x464/0x610 net/dccp/minisocks.c:121
dccp_v6_request_recv_sock+0x1f6/0x1960 net/dccp/ipv6.c:457
dccp_check_req+0x335/0x5a0 net/dccp/minisocks.c:186
dccp_v6_rcv+0x69e/0x1d00 net/dccp/ipv6.c:711
ip6_input_finish+0x46d/0x17a0 net/ipv6/ip6_input.c:279
NF_HOOK include/linux/netfilter.h:257 [inline]
ip6_input+0xdb/0x590 net/ipv6/ip6_input.c:322
dst_input include/net/dst.h:507 [inline]
ip6_rcv_finish+0x289/0x890 net/ipv6/ip6_input.c:69
NF_HOOK include/linux/netfilter.h:257 [inline]
ipv6_rcv+0x12ec/0x23d0 net/ipv6/ip6_input.c:203
__netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190
__netif_receive_skb+0x2a/0x170 net/core/dev.c:4228
process_backlog+0xe5/0x6c0 net/core/dev.c:4839
napi_poll net/core/dev.c:5202 [inline]
net_rx_action+0xe70/0x1900 net/core/dev.c:5267
__do_softirq+0x2fb/0xb7d kernel/softirq.c:284
Memory state around the buggy address:
ffff88003713bd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88003713bd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88003713be00: fc fc fc fc fc fc fc fc fc fc fb fb fb fb fb fb
^

Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Tested-by: Dmitry Vyukov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net/dccp: dccp_list_has_service can be boolean

This patch makes dccp_list_has_service return bool due to this
particular function only using either one or zero as its return
value.

No functional ch

net/dccp: dccp_list_has_service can be boolean

This patch makes dccp_list_has_service return bool due to this
particular function only using either one or zero as its return
value.

No functional change.

Signed-off-by: Yaowei Bai <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

ipv4: dccp: handle ICMP messages on DCCP_NEW_SYN_RECV request sockets

dccp_v4_err() can restrict lookups to ehash table, and not to listeners.

Note this patch creates the infrastructure, but this m

ipv4: dccp: handle ICMP messages on DCCP_NEW_SYN_RECV request sockets

dccp_v4_err() can restrict lookups to ehash table, and not to listeners.

Note this patch creates the infrastructure, but this means that ICMP
messages for request sockets are ignored until complete conversion.

New dccp_req_err() helper is exported so that we can use it in IPv6
in following patch.

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

inet: remove sk_listener parameter from syn_ack_timeout()

It is not needed, and req->sk_listener points to the listener anyway.
request_sock argument can be const.

Signed-off-by: Eric Dumazet <edum

inet: remove sk_listener parameter from syn_ack_timeout()

It is not needed, and req->sk_listener points to the listener anyway.
request_sock argument can be const.

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

UAPI: (Scripted) Disintegrate include/linux

Signed-off-by: David Howells <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Acked-by: Michae

UAPI: (Scripted) Disintegrate include/linux

Signed-off-by: David Howells <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Acked-by: Michael Kerrisk <[email protected]>
Acked-by: Paul E. McKenney <[email protected]>
Acked-by: Dave Jones <[email protected]>

show more ...

inet: makes syn_ack_timeout mandatory

There are two struct request_sock_ops providers, tcp and dccp.

inet_csk_reqsk_queue_prune() can avoid testing syn_ack_timeout being
NULL if we make it non NULL

inet: makes syn_ack_timeout mandatory

There are two struct request_sock_ops providers, tcp and dccp.

inet_csk_reqsk_queue_prune() can avoid testing syn_ack_timeout being
NULL if we make it non NULL like syn_ack_timeout

Signed-off-by: Eric Dumazet <[email protected]>
Cc: Gerrit Renker <[email protected]>
Cc: [email protected]
Signed-off-by: David S. Miller <[email protected]>

show more ...

dccp: fix bug in sequence number validation during connection setup

This fixes a bug in the sequence number validation during the initial handshake.

The code did not treat the initial sequence numb

dccp: fix bug in sequence number validation during connection setup

This fixes a bug in the sequence number validation during the initial handshake.

The code did not treat the initial sequence numbers ISS and ISR as read-only and
did not keep state for GSR and GSS as required by the specification. This causes
problems with retransmissions during the initial handshake, causing the
budding connection to be reset.

This patch now treats ISS/ISR as read-only and tracks GSS/GSR as required.

Signed-off-by: Samuel Jero <[email protected]>
Signed-off-by: Gerrit Renker <[email protected]>

show more ...

net: remove interrupt.h inclusion from netdevice.h

* remove interrupt.g inclusion from netdevice.h -- not needed
* fixup fallout, add interrupt.h and hardirq.h back where needed.

Signed-off-by: Ale

net: remove interrupt.h inclusion from netdevice.h

* remove interrupt.g inclusion from netdevice.h -- not needed
* fixup fallout, add interrupt.h and hardirq.h back where needed.

Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

dccp: clean up unused DCCP_STATE_MASK definition

Remove unused DCCP_STATE_MASK macro.

Signed-off-by: Shan Wei <[email protected]>
Acked-by: Gerrit Renker <[email protected]>
Signed-off-by:

dccp: clean up unused DCCP_STATE_MASK definition

Remove unused DCCP_STATE_MASK macro.

Signed-off-by: Shan Wei <[email protected]>
Acked-by: Gerrit Renker <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

dccp: Policy-based packet dequeueing infrastructure

This patch adds a generic infrastructure for policy-based dequeueing of
TX packets and provides two policies:
* a simple FIFO policy (which is th

dccp: Policy-based packet dequeueing infrastructure

This patch adds a generic infrastructure for policy-based dequeueing of
TX packets and provides two policies:
* a simple FIFO policy (which is the default) and
* a priority based policy (set via socket options).
Both policies honour the tx_qlen sysctl for the maximum size of the write
queue (can be overridden via socket options).

The priority policy uses skb->priority internally to assign an u32 priority
identifier, using the same ranking as SO_PRIORITY. The skb->priority field
is set to 0 when the packet leaves DCCP. The priority is supplied as ancillary
data using cmsg(3), the patch also provides the requisite parsing routines.

Signed-off-by: Tomasz Grobelny <[email protected]>
Signed-off-by: Gerrit Renker <[email protected]>

show more ...

dccp ccid-2: Schedule Sync as out-of-band mechanism

The problem with Ack Vectors is that
i) their length is variable and can in principle grow quite large,
ii) it is hard to predict exactly how l

dccp ccid-2: Schedule Sync as out-of-band mechanism

The problem with Ack Vectors is that
i) their length is variable and can in principle grow quite large,
ii) it is hard to predict exactly how large they will be.

Due to the second point it seems not a good idea to reduce the MPS; in
particular when on average there is enough room for the Ack Vector and an
increase in length is momentarily due to some burst loss, after which the
Ack Vector returns to its normal/average length.

The solution taken by this patch is to subtract a minimum-expected Ack Vector
length from the MPS, and to defer any larger Ack Vectors onto a separate
Sync - but only if indeed there is no space left on the skb.

This patch provides the infrastructure to schedule Sync-packets for transporting
(urgent) out-of-band data. Its signalling is quicker than scheduling an Ack, since
it does not need to wait for new application data.

Signed-off-by: Gerrit Renker <[email protected]>

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dccp: Extend CCID packet dequeueing interface

This extends the packet dequeuing interface of dccp_write_xmit() to allow
1. CCIDs to take care of timing when the next packet may be sent;
2. delayed

dccp: Extend CCID packet dequeueing interface

This extends the packet dequeuing interface of dccp_write_xmit() to allow
1. CCIDs to take care of timing when the next packet may be sent;
2. delayed sending (as before, with an inter-packet gap up to 65.535 seconds).

The main purpose is to take CCID-2 out of its polling mode (when it is network-
limited, it tries every millisecond to send, without interruption).

The mode of operation for (2) is as follows:
* new packet is enqueued via dccp_sendmsg() => dccp_write_xmit(),
* ccid_hc_tx_send_packet() detects that it may not send (e.g. window full),
* it signals this condition via `CCID_PACKET_WILL_DEQUEUE_LATER',
* dccp_write_xmit() returns without further action;
* after some time the wait-condition for CCID becomes true,
* that CCID schedules the tasklet,
* tasklet function calls ccid_hc_tx_send_packet() via dccp_write_xmit(),
* since the wait-condition is now true, ccid_hc_tx_packet() returns "send now",
* packet is sent, and possibly more (since dccp_write_xmit() loops).

Code reuse: the taskled function calls dccp_write_xmit(), the timer function
reduces to a wrapper around the same code.

Signed-off-by: Gerrit Renker <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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dccp: Replace magic CCID-specific numbers by symbolic constants

The constants DCCPO_{MIN,MAX}_CCID_SPECIFIC are nowhere used in the code, but
instead for the CCID-specific options numbers are used.

dccp: Replace magic CCID-specific numbers by symbolic constants

The constants DCCPO_{MIN,MAX}_CCID_SPECIFIC are nowhere used in the code, but
instead for the CCID-specific options numbers are used.

This patch unifies the use of CCID-specific option numbers, by adding symbolic
names reflecting the definitions in RFC 4340, 10.3.

Signed-off-by: Gerrit Renker <[email protected]>

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dccp: Initialisation and type-checking of feature sysctls

This patch takes care of initialising and type-checking sysctls
related to feature negotiation. Type checking is important since some
of the

dccp: Initialisation and type-checking of feature sysctls

This patch takes care of initialising and type-checking sysctls
related to feature negotiation. Type checking is important since some
of the sysctls now directly impact the feature-negotiation process.

The sysctls are initialised with the known default values for each
feature. For the type-checking the value constraints from RFC 4340
are used:

* Sequence Window uses the specified Wmin=32, the maximum is ulong (4 bytes),
tested and confirmed that it works up to 4294967295 - for Gbps speed;
* Ack Ratio is between 0 .. 0xffff (2-byte unsigned integer);
* CCIDs are between 0 .. 255;
* request_retries, retries1, retries2 also between 0..255 for good measure;
* tx_qlen is checked to be non-negative;
* sync_ratelimit remains as before.

Notes:
------
1. Die s@sysctl_dccp_feat@sysctl_dccp@g since the sysctls are now in feat.c.
2. As pointed out by Arnaldo, the pattern of type-checking repeats itself in
other places, sometimes with exactly the same kind of definitions (e.g.
"static int zero;"). It may be a good idea (kernel janitors?) to consolidate
type checking. For the sake of keeping the changeset small and in order not
to affect other subsystems, I have not strived to generalise here.

Signed-off-by: Gerrit Renker <[email protected]>
Acked-by: Ian McDonald <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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dccp: Implement both feature-local and feature-remote Sequence Window feature

This adds full support for local/remote Sequence Window feature, from which the
* sequence-number-validity (W) and
*

dccp: Implement both feature-local and feature-remote Sequence Window feature

This adds full support for local/remote Sequence Window feature, from which the
* sequence-number-validity (W) and
* acknowledgment-number-validity (W') windows
derive as specified in RFC 4340, 7.5.3.

Specifically, the following is contained in this patch:
* integrated new socket fields into dccp_sk;
* updated the update_gsr/gss routines with regard to these fields;
* updated handler code: the Sequence Window feature is located at the TX side,
so the local feature is meant if the handler-rx flag is false;
* the initialisation of `rcv_wnd' in reqsk is removed, since
- rcv_wnd is not used by the code anywhere;
- sequence number checks are not done in the LISTEN state (cf. 7.5.3);
- dccp_check_req checks the Ack number validity more rigorously;
* the `struct dccp_minisock' became empty and is now removed.

Signed-off-by: Gerrit Renker <[email protected]>
Acked-by: Ian McDonald <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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dccp: Initialisation framework for feature negotiation

This initialises feature negotiation from two tables, which are in
turn are initialised from sysctls.

As a novel feature, specifics of the imp

dccp: Initialisation framework for feature negotiation

This initialises feature negotiation from two tables, which are in
turn are initialised from sysctls.

As a novel feature, specifics of the implementation (e.g. that short
seqnos and ECN are not yet available) are advertised for robustness.

Signed-off-by: Gerrit Renker <[email protected]>
Acked-by: Ian McDonald <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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dccp ccid-2: Phase out the use of boolean Ack Vector sysctl

This removes the use of the sysctl and the minisock variable for the Send Ack
Vector feature, as it now is handled fully dynamically via f

dccp ccid-2: Phase out the use of boolean Ack Vector sysctl

This removes the use of the sysctl and the minisock variable for the Send Ack
Vector feature, as it now is handled fully dynamically via feature negotiation
(i.e. when CCID-2 is enabled, Ack Vectors are automatically enabled as per
RFC 4341, 4.).

Using a sysctl in parallel to this implementation would open the door to
crashes, since much of the code relies on tests of the boolean minisock /
sysctl variable. Thus, this patch replaces all tests of type

if (dccp_msk(sk)->dccpms_send_ack_vector)
/* ... */
with
if (dp->dccps_hc_rx_ackvec != NULL)
/* ... */

The dccps_hc_rx_ackvec is allocated by the dccp_hdlr_ackvec() when feature
negotiation concluded that Ack Vectors are to be used on the half-connection.
Otherwise, it is NULL (due to dccp_init_sock/dccp_create_openreq_child),
so that the test is a valid one.

The activation handler for Ack Vectors is called as soon as the feature
negotiation has concluded at the
* server when the Ack marking the transition RESPOND => OPEN arrives;
* client after it has sent its ACK, marking the transition REQUEST => PARTOPEN.

Adding the sequence number of the Response packet to the Ack Vector has been
removed, since
(a) connection establishment implies that the Response has been received;
(b) the CCIDs only look at packets received in the (PART)OPEN state, i.e.
this entry will always be ignored;
(c) it can not be used for anything useful - to detect loss for instance, only
packets received after the loss can serve as pseudo-dupacks.

There was a FIXME to change the error code when dccp_ackvec_add() fails.
I removed this after finding out that:
* the check whether ackno < ISN is already made earlier,
* this Response is likely the 1st packet with an Ackno that the client gets,
* so when dccp_ackvec_add() fails, the reason is likely not a packet error.

Signed-off-by: Gerrit Renker <[email protected]>
Acked-by: Ian McDonald <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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dccp: Remove manual influence on NDP Count feature

Updating the NDP count feature is handled automatically now:
* for CCID-2 it is disabled, since the code does not use NDP counts;
* for CCID-3 it

dccp: Remove manual influence on NDP Count feature

Updating the NDP count feature is handled automatically now:
* for CCID-2 it is disabled, since the code does not use NDP counts;
* for CCID-3 it is enabled, as NDP counts are used to determine loss lengths.

Allowing the user to change NDP values leads to unpredictable and failing
behaviour, since it is then possible to disable NDP counts even when they
are needed (e.g. in CCID-3).

This means that only those user settings are sensible that agree with the
values for Send NDP Count implied by the choice of CCID. But those settings
are already activated by the feature negotiation (CCID dependency tracking),
hence this form of support is redundant.

At startup the initialisation of the NDP count feature uses the default
value of 0, which is done implicitly by the zeroing-out of the socket when
it is allocated. If the choice of CCID or feature negotiation enables NDP
count, this will then be updated via the NDP activation handler.

Signed-off-by: Gerrit Renker <[email protected]>
Acked-by: Ian McDonald <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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dccp: Remove obsolete parts of the old CCID interface

The TX/RX CCIDs of the minisock are now redundant: similar to the Ack Vector
case, their value equals initially that of the sysctl, but at the e

dccp: Remove obsolete parts of the old CCID interface

The TX/RX CCIDs of the minisock are now redundant: similar to the Ack Vector
case, their value equals initially that of the sysctl, but at the end of
feature negotiation may be something different.

The old interface removed by this patch thus has been replaced by the newer
interface to dynamically query the currently loaded CCIDs.

Also removed are the constructors for the TX CCID and the RX CCID, since the
switch "rx <-> non-rx" is done by the handler in minisocks.c (and the handler
is the only place in the code where CCIDs are loaded).

Signed-off-by: Gerrit Renker <[email protected]>
Acked-by: Ian McDonald <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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dccp: Set per-connection CCIDs via socket options

With this patch, TX/RX CCIDs can now be changed on a per-connection
basis, which overrides the defaults set by the global sysctl variables
for TX/RX

dccp: Set per-connection CCIDs via socket options

With this patch, TX/RX CCIDs can now be changed on a per-connection
basis, which overrides the defaults set by the global sysctl variables
for TX/RX CCIDs.

To make full use of this facility, the remaining patches of this patch
set are needed, which track dependencies and activate negotiated
feature values.

Signed-off-by: Gerrit Renker <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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dccp: Deprecate Ack Ratio sysctl

This patch deprecates the Ack Ratio sysctl, since
* Ack Ratio is entirely ignored by CCID-3 and CCID-4,
* Ack Ratio currently doesn't work in CCID-2 (i.e. is alway

dccp: Deprecate Ack Ratio sysctl

This patch deprecates the Ack Ratio sysctl, since
* Ack Ratio is entirely ignored by CCID-3 and CCID-4,
* Ack Ratio currently doesn't work in CCID-2 (i.e. is always set to 1);
* even if it would work in CCID-2, there is no point for a user to change it:
- Ack Ratio is constrained by cwnd (RFC 4341, 6.1.2),
- if Ack Ratio > cwnd, the system resorts to spurious RTO timeouts
(since waiting for Acks which will never arrive in this window),
- cwnd is not a user-configurable value.

The only reasonable place for Ack Ratio is to print it for debugging. It is
planned to do this later on, as part of e.g. dccp_probe.

With this patch Ack Ratio is now under full control of feature negotiation:
* Ack Ratio is resolved as a dependency of the selected CCID;
* if the chosen CCID supports it (i.e. CCID == CCID-2), Ack Ratio is set to
the default of 2, following RFC 4340, 11.3 - "New connections start with Ack
Ratio 2 for both endpoints";
* what happens then is part of another patch set, since it concerns the
dynamic update of Ack Ratio while the connection is in full flight.

Thanks to Tomasz Grobelny for discussion leading up to this patch.

Signed-off-by: Gerrit Renker <[email protected]>
Acked-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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dccp: Feature negotiation for minimum-checksum-coverage

This provides feature negotiation for server minimum checksum coverage
which so far has been missing.

Since sender/receiver coverage values r

dccp: Feature negotiation for minimum-checksum-coverage

This provides feature negotiation for server minimum checksum coverage
which so far has been missing.

Since sender/receiver coverage values range only from 0...15, their
type has also been reduced in size from u16 to u4.

Feature-negotiation options are now generated for both sender and receiver
coverage, i.e. when the peer has `forgotten' to enable partial coverage
then feature negotiation will automatically enable (negotiate) the partial
coverage value for this connection.

Signed-off-by: Gerrit Renker <[email protected]>
Acked-by: Ian McDonald <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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