Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
![]() ip6_make_flowlabel() determines the flow label for IPv6 packets. It's supposed to be passed a flow label, which it returns as is if non-0 and in some other cases, otherwise it calculates a new value. The problem is callers often pass a flowi6.flowlabel, which may also contain traffic class bits. If the traffic class is non-0 ip6_make_flowlabel() mistakes the non-0 it gets as a flow label and returns the whole thing. Thus it can return a 'flow label' longer than 20b and the low 20b of that is typically 0 resulting in packets with 0 label. Moreover, different packets of a flow may be labeled differently. For a TCP flow with ECN non-payload and payload packets get different labels as exemplified by this pair of consecutive packets: (pure ACK) Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2:: 0110 .... = Version: 6 .... 0000 0000 .... .... .... .... .... = Traffic Class: 0x00 (DSCP: CS0, ECN: Not-ECT) .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0) .... .... ..00 .... .... .... .... .... = Explicit Congestion Notification: Not ECN-Capable Transport (0) .... .... .... 0001 1100 1110 0100 1001 = Flow Label: 0x1ce49 Payload Length: 32 Next Header: TCP (6) (payload) Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2:: 0110 .... = Version: 6 .... 0000 0010 .... .... .... .... .... = Traffic Class: 0x02 (DSCP: CS0, ECN: ECT(0)) .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0) .... .... ..10 .... .... .... .... .... = Explicit Congestion Notification: ECN-Capable Transport codepoint '10' (2) .... .... .... 0000 0000 0000 0000 0000 = Flow Label: 0x00000 Payload Length: 688 Next Header: TCP (6) This patch allows ip6_make_flowlabel() to be passed more than just a flow label and has it extract the part it really wants. This was simpler than modifying the callers. With this patch packets like the above become Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2:: 0110 .... = Version: 6 .... 0000 0000 .... .... .... .... .... = Traffic Class: 0x00 (DSCP: CS0, ECN: Not-ECT) .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0) .... .... ..00 .... .... .... .... .... = Explicit Congestion Notification: Not ECN-Capable Transport (0) .... .... .... 1010 1111 1010 0101 1110 = Flow Label: 0xafa5e Payload Length: 32 Next Header: TCP (6) Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2:: 0110 .... = Version: 6 .... 0000 0010 .... .... .... .... .... = Traffic Class: 0x02 (DSCP: CS0, ECN: ECT(0)) .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0) .... .... ..10 .... .... .... .... .... = Explicit Congestion Notification: ECN-Capable Transport codepoint '10' (2) .... .... .... 1010 1111 1010 0101 1110 = Flow Label: 0xafa5e Payload Length: 688 Next Header: TCP (6) Signed-off-by: Dimitris Michailidis <dmichail@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.