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author | Alexander V. Chernikov <melifaro@FreeBSD.org> | 2015-09-16 14:26:28 +0000 |
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committer | Alexander V. Chernikov <melifaro@FreeBSD.org> | 2015-09-16 14:26:28 +0000 |
commit | 1fe201c322f93424e29581c5622da7cde44db51f (patch) | |
tree | e04e3fcd4841d6aa1ce593fcc38aa9bb51b4cd33 /sys/ofed | |
parent | 5c5fb901eb05f91db8e914500357953bf475b8a0 (diff) | |
download | src-1fe201c322f93424e29581c5622da7cde44db51f.tar.gz src-1fe201c322f93424e29581c5622da7cde44db51f.zip |
Simplify the way of attaching IPv6 link-layer header.
Problem description:
How do we currently perform layer 2 resolution and header imposition:
For IPv4 we have the following chain:
ip_output() -> (ether|atm|whatever)_output() -> arpresolve()
Lookup is done in proper place (link-layer output routine) and it is possible
to provide cached lle data.
For IPv6 situation is more complex:
ip6_output() -> nd6_output() -> nd6_output_ifp() -> (whatever)_output() ->
nd6_storelladdr()
We have ip6_ouput() which calls nd6_output() instead of link output routine.
nd6_output() does the following:
* checks if lle exists, creates it if needed (similar to arpresolve())
* performes lle state transitions (similar to arpresolve())
* calls nd6_output_ifp() which pushes packets to link output routine along
with running SeND/MAC hooks regardless of lle state
(e.g. works as run-hooks placeholder).
After that, iface output routine like ether_output() calls nd6_storelladdr()
which performs lle lookup once again.
As a result, we perform lookup twice for each outgoing packet for most types
of interfaces. We also need to maintain runtime-checked table of 'nd6-free'
interfaces (see nd6_need_cache()).
Fix this behavior by eliminating first ND lookup. To be more specific:
* make all nd6_output() consumers use nd6_output_ifp() instead
* rename nd6_output[_slow]() to nd6_resolve_[slow]()
* convert nd6_resolve() and nd6_resolve_slow() to arpresolve() semantics,
e.g. copy L2 address to buffer instead of pushing packet towards lower
layers
* Make all nd6_storelladdr() users use nd6_resolve()
* eliminate nd6_storelladdr()
The resulting callchain is the following:
ip6_output() -> nd6_output_ifp() -> (whatever)_output() -> nd6_resolve()
Error handling:
Currently sending packet to non-existing la results in ip6_<output|forward>
-> nd6_output() -> nd6_output _lle() which returns 0.
In new scenario packet is propagated to <ether|whatever>_output() ->
nd6_resolve() which will return EWOULDBLOCK, and that result
will be converted to 0.
(And EWOULDBLOCK is actually used by IB/TOE code).
Sponsored by: Yandex LLC
Differential Revision: https://reviews.freebsd.org/D1469
Notes
Notes:
svn path=/head/; revision=287861
Diffstat (limited to 'sys/ofed')
-rw-r--r-- | sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c b/sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c index 35e16417a5f6..53ac66d304d7 100644 --- a/sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c +++ b/sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c @@ -1333,7 +1333,7 @@ ipoib_output(struct ifnet *ifp, struct mbuf *m, else if (m->m_flags & M_MCAST) ipv6_ib_mc_map(&((struct sockaddr_in6 *)dst)->sin6_addr, ifp->if_broadcastaddr, edst); else - error = nd6_storelladdr(ifp, m, dst, (u_char *)edst, NULL); + error = nd6_resolve(ifp, is_gw, m, dst, edst, NULL); if (error) return error; type = htons(ETHERTYPE_IPV6); |