This change intends to run the whole network stack in softint context
(or normal LWP), not hardware interrupt context. Note that the work is
still incomplete by this change; to that end, we also have to softint-ify
if_link_state_change (and bpf) which can still run in hardware interrupt.
This change softint-ifies at ifp->if_input that is called from
each device driver (and ieee80211_input) to ensure Layer 2 runs
in softint (e.g., ether_input and bridge_input). To this end,
we provide a framework (called percpuq) that utlizes softint(9)
and percpu ifqueues. With this patch, rxintr of most drivers just
queues received packets and schedules a softint, and the softint
dequeues packets and does rest packet processing.
To minimize changes to each driver, percpuq is allocated in struct
ifnet for now and that is initialized by default (in if_attach).
We probably have to move percpuq to softc of each driver, but it's
future work. At this point, only wm(4) has percpuq in its softc
as a reference implementation.
Additional information including performance numbers can be found
in the thread at tech-kern@ and tech-net@:
http://mail-index.netbsd.org/tech-kern/2016/01/14/msg019997.html
Acknowledgment: riastradh@ greatly helped this work.
Thank you very much!
This change was intended, but Nakahara-san had already made a better
one locally! So I'll let him commit that one, and I'll try not to
step on anyone's toes again.
Mostly mechanical change to replace it, culling some now-needless
boilerplate around all the users.
This does not substantively change the ip_encap API or eliminate
abuse of sketchy pointer casts -- that will come later, and will be
easier now that it is not tangled up with struct protosw.
You can't use this unless you know what it is a priori: the formal
prototype is variadic, and the different instances (e.g., ip_output,
route_output) have different real prototypes.
Convert the only user of it, raw_send in net/raw_cb.c, to take an
explicit callback argument. Convert the only instances of it,
route_output and key_output, to such explicit callbacks for raw_send.
Use assertions to make sure the conversion to explicit callbacks is
warranted.
Discussed on tech-net with no objections:
https://mail-index.netbsd.org/tech-net/2016/01/16/msg005484.html
lltable and llentry were introduced to replace ARP cache data structure
for further restructuring of the routing table: L2 nexthop cache
separation. This change replaces the NDP cache data structure
(llinfo_nd6) with them as well as ARP.
One noticeable change is for neighbor cache GC mechanism that was
introduced to prevent IPv6 DoS attacks. net.inet6.ip6.neighborgcthresh
was the max number of caches that we store in the system. After
introducing lltable/llentry, the value is changed to be per-interface
basis because lltable/llentry stores neighbor caches in each interface
separately. And the change brings one degradation; the old GC mechanism
dropped exceeded packets based on LRU while the new implementation drops
packets in order from the beginning of lltable (a hash table + linked
lists). It would be improved in the future.
Added functions in in6.c come from FreeBSD (as of r286629) and are
tweaked for NetBSD.
Proposed on tech-kern and tech-net.
This is a restructuring for coming changes to nd6 (replacing
llinfo_nd6 with llentry). Once we have a lock of llinfo_nd6,
we need to pass it to nd6_ns_output with holding the lock.
However, in a function subsequent to nd6_ns_output, the llinfo_nd6
may be looked up, i.e., its lock would be acquired again.
To avoid such a situation, pass only required data (in6_addr) to
nd6_ns_output instead of passing whole llinfo_nd6.
Inspired by FreeBSD
We have to update icmp6_redirect_timeout_q as well as icmp6_redirtimeout
when changing net.inet6.icmp6.redirtimeout via sysctl. The updating logic
is copied from sysctl_net_inet_icmp_redirtimeout.
This change is from s-yamaguchi@IIJ (with KNF by ozaki-r) and fixes
PR kern/50240.
We have to check and avoid to rtfree the original rtentry passed to
nd6_output even when manipulating gateway routes.
This fixes panic on assertion "ro->_ro_rt ==NULL || ro->_ro_rt->rt_refcnt > 0"
failure and probably PR kern/50161.
Some codes in sys/net* use time_second to manage time periods such as
cache expirations. However, time_second doesn't increase monotonically
and can leap by say settimeofday(2) according to time_second(9). We
should use time_uptime instead of it to avoid such time leaps.
This change replaces time_second with time_uptime. Additionally it
converts a time based on time_uptime to a time based on time_second
when the kernel passes the time to userland programs that expect
the latter, and vice versa.
Note that we shouldn't leak time_uptime to other hosts over the
netowrk. My investigation shows there is no such leak:
http://mail-index.netbsd.org/tech-net/2015/08/06/msg005332.html
Discussed on tech-kern and tech-net.
rt_refcnt of rtentry was used in bad manners, for example, direct rt_refcnt++
and rt_refcnt-- outside route.c, "rt->rt_refcnt++; rtfree(rt);" idiom, and
touching rt after rt->rt_refcnt--.
These abuses seem to be needed because rt_refcnt manages only references
between rtentry and doesn't take care of references during packet processing
(IOW references from local variables). In order to reduce the above abuses,
the latter cases should be counted by rt_refcnt as well as the former cases.
This change improves consistency of use of rt_refcnt:
- rtentry is always accessed with rt_refcnt incremented
- rtentry's rt_refcnt is decremented after use (rtfree is always used instead
of rt_refcnt--)
- functions returning rtentry increment its rt_refcnt (and caller rtfree it)
Note that rt_refcnt prevents rtentry from being freed but doesn't prevent
rtentry from being updated. Toward MP-safe, we need to provide another
protection for rtentry, e.g., locks. (Or introduce a better data structure
allowing concurrent readers during updates.)
nd6_numroutes is intended to be incremented when a route is added via RA
and decremented when a RA route is deleted. However, a decrement of a RA
route was skipped when there remained references to the RA route.
