gnrc_ipv6: move ipv6_ext iteration out of ext_demux() #10234

miri64 · 2018-10-23T22:42:29Z

Contribution description

Since with #10233 we now assume IPv6 packets always to not be pre-parsed, we can iterate over the extension headers by gradually "eating" them away. This allows us to move the iteration over them out of gnrc_ipv6_ext_demux() and into gnrc_ipv6_demux().

By moving the iteration over all extension headers out of gnrc_ipv6_ext_demux() we also can

simplify the extension header handling a lot, as it now just a loop inside gnrc_ipv6_demux(),
remove the recursion to gnrc_ipv6_demux() within gnrc_ipv6_ext_demux().
some cleanup, possible due to all the things above.

I also piggy-backed some follow-up work that are related to demuxing and the fact that they are not pre-parsed:

since they are not preparsed, we don't haved to specifically write-protect all the extension headers up to the IPv6 packet, as the whole (un-parsed) packet was already write protected when first received.
since the gnrc_ipv6_ext doesn't recurse into gnrc_ipv6_demux() anymore, that function can be made private again.

Testing procedure

I used scapy to inject packets with and without extension headers into a native instance of gnrc_networking:

On RIOT:

udp server start 1337

Within scapy (be aware that to send Ethernet frames, root privileges are required, so best start it with sudo scapy):

DST_ADDR = "fe80::ac4e:aeff:fec0:caab" # use your RIOT node's address here instead
# first send a simple UDP packet to test if the server is working
sendp(Ether() / 
      IPv6(dst=DST_ADDR) /
      UDP(sport=1339, dport=1337) /
      "\x00\x01", iface="tapbr0")
# now send some extension headers (we assume they all are not parsed)
sendp(Ether() /
      IPv6(dst=DST_ADDR) /
      IPv6ExtHdrDestOpt() /
      UDP(sport=1339, dport=1337) /
      "\x00\x01", iface="tapbr0")
sendp(Ether() /
      IPv6(dst=DST_ADDR) /
      IPv6ExtHdrRouting() /
      UDP(sport=1339, dport=1337) /
      "\x00\x01", iface="tapbr0")
# ...

You can find some documentation on IPv6 extension headers in this document

You can also just redo the testing procedures in #10229.

Issues/PRs references

Depends on #10233 (and its dependencies)

…HEAD

… HEAD

…HEAD

miri64 · 2018-10-25T17:54:08Z

Rebased to current #10233

sys/net/gnrc/network_layer/ipv6/ext/gnrc_ipv6_ext.c

sys/include/net/gnrc/pktbuf.h

sys/net/gnrc/network_layer/ipv6/ext/gnrc_ipv6_ext.c

miri64 · 2018-10-29T19:32:07Z

Rebased to current #10233.

miri64 · 2018-10-30T17:06:57Z

Already found the first batch of errors due to my tests :-)

miri64 · 2018-12-13T13:30:50Z

Fixed typo in as squashable commit.

jia200x · 2018-12-13T13:39:12Z

1-fundamentals done. Nice cleanup btw!

jia200x · 2018-12-13T14:56:49Z

well, it seems to work. I will run #10229 tests as well

jia200x · 2018-12-13T15:06:21Z

#10229 tests run fine.

miri64 · 2018-12-13T15:19:52Z

May I squash?

jia200x · 2018-12-13T15:30:18Z

May I squash?

Yes, sure

jia200x · 2018-12-13T15:31:24Z

vera++ doesn't report problems with the introduced changes. There are some consecutive empty lines but not in the scope of this PR.

miri64 · 2018-12-13T15:33:14Z

Squashed

sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c

Since with RIOT-OS#10233 we now assume IPv6 packets always to not be pre-parsed, we can iterate over the extension headers by gradually "eating" them away. This allows us to move the iteration over them out of `gnrc_ipv6_ext_demux()` and into `gnrc_ipv6_demux()`. By moving the iteration over all extension headers out of `gnrc_ipv6_ext_demux()` we also can 1. simplify the extension header handling a lot, as it now just a loop inside `gnrc_ipv6_demux()`, 2. remove the recursion to `gnrc_ipv6_demux()` within `gnrc_ipv6_ext_demux()`.

As `pkt` isn't pre-parsed the write-protection of *the whole* packet (except the netif-header) comes for free, when this was done in the receive routine of IPv6.

Since the recursion into `gnrc_ipv6_demux()` was removed in `gnrc_ipv6_ext`, `gnrc_ipv6.c` is the only user of this function, so it can be made private. It was only made public so it can be used from `gnrc_ipv6_ext`.

With the preceding changes the subject of the deprecation note on `gnrc_pktbuf_duplicate_upto()` becomes actual and thus doesn't need to be referred to in future but past tense.

miri64 · 2018-12-13T16:54:11Z

Murdock likes it now :)

jia200x

ACK

jia200x · 2018-12-14T09:43:55Z

Thanks @miri64 !

miri64 · 2018-12-14T10:12:08Z

Thanks for your review!

miri64 added Area: network Area: Networking Type: cleanup The issue proposes a clean-up / The PR cleans-up parts of the codebase / documentation State: waiting for other PR State: The PR requires another PR to be merged first labels Oct 23, 2018

miri64 requested review from jnohlgard, cgundogan and bergzand October 23, 2018 22:42

miri64 added the Process: API change Integration Process: PR contains or issue proposes an API change. Should be handled with care. label Oct 23, 2018

miri64 force-pushed the gnrc_ipv6/enh/iterate-out-of-ext branch from 8a4ff3e to b766b10 Compare October 23, 2018 22:58

miri64 added a commit to miri64/RIOT that referenced this pull request Oct 23, 2018

Merge branch 'gnrc_ipv6/enh/iterate-out-of-ext' (RIOT-OS#10234) into …

d2247ab

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miri64 mentioned this pull request Oct 24, 2018

gnrc_ipv6_ext: needs heavy refactoring #10133

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miri64 added a commit to miri64/RIOT that referenced this pull request Oct 24, 2018

Merge branch 'gnrc_ipv6/enh/iterate-out-of-ext' (RIOT-OS#10234) into…

80fd345

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miri64 mentioned this pull request Oct 24, 2018

gnrc_ipv6_ext: merge _handle_rh and gnrc_ipv6_ext_rh_process #10238

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miri64 force-pushed the gnrc_ipv6/enh/iterate-out-of-ext branch from 870a055 to 252540e Compare October 24, 2018 12:56

This was referenced Oct 24, 2018

gnrc_ipv6_ext_rh: add ICMPv6 error message sending #10242

Merged

gnrc_ipv6: handle hop-by-hop option before forwarding #10244

Merged

gnrc_ipv6_ext: move ipv6_ext_rh (partly) to GNRC #10231

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miri64 force-pushed the gnrc_ipv6/enh/iterate-out-of-ext branch 2 times, most recently from 92f18bb to 8029b4f Compare October 24, 2018 19:33

miri64 added a commit to miri64/RIOT that referenced this pull request Oct 24, 2018

Merge branch 'gnrc_ipv6/enh/iterate-out-of-ext' (RIOT-OS#10234) into …

e80d801

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jia200x added the Reviewed: 1-fundamentals The fundamentals of the PR were reviewed according to the maintainer guidelines label Dec 13, 2018

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miri64 force-pushed the gnrc_ipv6/enh/iterate-out-of-ext branch from 76256a9 to d7c4078 Compare December 13, 2018 15:33

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miri64 and others added 6 commits December 13, 2018 17:22

gnrc_ipv6_ext: remove unnecessary pkt write-protection

f671a87

As `pkt` isn't pre-parsed the write-protection of *the whole* packet (except the netif-header) comes for free, when this was done in the receive routine of IPv6.

gnrc_ipv6: make next-header demuxer private

764ed8c

Since the recursion into `gnrc_ipv6_demux()` was removed in `gnrc_ipv6_ext`, `gnrc_ipv6.c` is the only user of this function, so it can be made private. It was only made public so it can be used from `gnrc_ipv6_ext`.

gnrc_ipv6: clean-up unrequired stuff after demux rework

e6df40d

gnrc_ipv6: rename should_release for clarity

b8f71c3

gnrc_pktbuf: update tense of deprecation note ;-)

4257b70

With the preceding changes the subject of the deprecation note on `gnrc_pktbuf_duplicate_upto()` becomes actual and thus doesn't need to be referred to in future but past tense.

miri64 force-pushed the gnrc_ipv6/enh/iterate-out-of-ext branch from d7c4078 to 4257b70 Compare December 13, 2018 16:22

jia200x approved these changes Dec 14, 2018

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jia200x merged commit b709e63 into RIOT-OS:master Dec 14, 2018

miri64 deleted the gnrc_ipv6/enh/iterate-out-of-ext branch December 14, 2018 10:11

aabadie added this to the Release 2019.01 milestone Dec 19, 2018

miri64 mentioned this pull request Aug 10, 2019

gnrc_ipv6_ext: conceptual error in packet buffer usage #7185

Closed

gnrc_ipv6: move ipv6_ext iteration out of ext_demux() #10234

gnrc_ipv6: move ipv6_ext iteration out of ext_demux() #10234

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Contribution description

Testing procedure

Issues/PRs references

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