gre(4): Add full support for gre key
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Authored by pouria on Sat, Sep 19, 8:06 PM.

Details

Reviewers

glebius
markj
ae

Group Reviewers

network

Summary

Allow multiple gre tunnels with same source and destination
tunnel with different gre keys.
Add a net.link.gre.key_fallback for backward compatibility
and set it to true by default.
Also write multikey tests for both IPv4 and IPv6 families.

Relnotes: yes

Test Plan

Create two tunnel with the same source and destination but with different gre key:

# ifconfig gre0 create inet tunnel 172.23.1.123 172.23.1.1 grekey 1
# ifconfig gre1 create inet tunnel 172.23.1.123 172.23.1.1 grekey 2
# ifconfig -a -g gre
gre0: flags=8050<POINTOPOINT,RUNNING,MULTICAST> metric 0 mtu 1476
        options=80000<LINKSTATE>
        tunnel inet 172.23.1.123 --> 172.23.1.1
        groups: gre
        grekey: 0x1 (1)
        nd6 options=829<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL,STABLEADDR>
gre1: flags=8050<POINTOPOINT,RUNNING,MULTICAST> metric 0 mtu 1476
        options=80000<LINKSTATE>
        tunnel inet 172.23.1.123 --> 172.23.1.1
        groups: gre
        grekey: 0x2 (2)
        nd6 options=829<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL,STABLEADDR>

# kyua test -k /usr/tests/Kyuafile sys/net/if_gre
sys/net/if_gre:gre6_basic  ->  passed  [1.330s]
sys/net/if_gre:gre6_csum  ->  passed  [1.490s]
sys/net/if_gre:gre4_key_fallback  ->  passed  [2.811s]
sys/net/if_gre:gre4_basic  ->  passed  [2.951s]
sys/net/if_gre:gre4_multikey  ->  passed  [2.836s]
sys/net/if_gre:gre4_key_mismatch_udpencap  ->  passed  [4.616s]
sys/net/if_gre:gre4_multikey_udpencap  ->  passed  [5.907s]
sys/net/if_gre:gre6_key  ->  passed  [3.830s]
sys/net/if_gre:gre4_key_mismatch  ->  passed  [7.565s]
sys/net/if_gre:gre_blind_options  ->  passed  [1.875s]
sys/net/if_gre:gre6_seq  ->  passed  [4.764s]
sys/net/if_gre:gre6_udpencap  ->  passed  [4.274s]
sys/net/if_gre:gre6_multikey  ->  passed  [8.662s]
sys/net/if_gre:gre6_multikey_udpencap  ->  passed  [6.621s]

Results file id is usr_tests.20260919-200756-603017
Results saved to /root/.kyua/store/results.usr_tests.20260919-200756-603017.db

14/14 passed (0 broken, 0 failed, 0 skipped)

Diff Detail

Repository

rG FreeBSD src repository

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Unit

Tests Skipped

Build Status

Buildable 77098
Build 73981: arc lint + arc unit

Event Timeline

pouria created this revision.Sat, Sep 19, 8:06 PM

pouria held this revision as a draft.

Herald added subscribers: ziaee, melifaro, ae, imp. · View Herald TranscriptSat, Sep 19, 8:06 PM

Harbormaster completed remote builds in B77098: Diff 187245.Sat, Sep 19, 8:06 PM

pouria edited the test plan for this revision. (Show Details)Sat, Sep 19, 8:14 PM

Handle EEXIST in ifconfig

Harbormaster completed remote builds in B77099: Diff 187246.Sat, Sep 19, 8:14 PM

I really want to keep gre simple and use my own geneve driver. but censorship in my country is not geneve friendly...
Tests are similar to each other, but they're important because we separate ipv4 and ipv6 logic.

Since I didn't touch the hash table logic. the proposed change is quite simple.
most of the logic is around net.link.gre.key_fallback for backward compatibility.
I'd be glad to remove the fallback logic, but beside our own compatibility break, Linux can be configured with separate inbound/outbound key.
So I decided to keep the fallback for now.

sys/net/if_gre.c
772	gre checksum is optinal and if set, it consume 16 bit for checksum and other 16 bit reserved. We need to skip those fields in order to access gre key. I didn't want to add another comment here. it makes it ugly or I should use extra `{}` for my if condition to make it pretty again, which is unnecessary :)