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author | zec <zec@FreeBSD.org> | 2009-05-05 10:56:12 +0000 |
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committer | zec <zec@FreeBSD.org> | 2009-05-05 10:56:12 +0000 |
commit | d78a1b1a824c4f5eb8cb3583bb5265f73dcc24dd (patch) | |
tree | 79a0bccccf2c92504cdf23ad15f7c1813bb3f926 /sys/netgraph/netgraph.h | |
parent | 8e4ffe653f6c9ff6da3eed58566ef35e77d530d0 (diff) | |
download | FreeBSD-src-d78a1b1a824c4f5eb8cb3583bb5265f73dcc24dd.zip FreeBSD-src-d78a1b1a824c4f5eb8cb3583bb5265f73dcc24dd.tar.gz |
Change the curvnet variable from a global const struct vnet *,
previously always pointing to the default vnet context, to a
dynamically changing thread-local one. The currvnet context
should be set on entry to networking code via CURVNET_SET() macros,
and reverted to previous state via CURVNET_RESTORE(). Recursions
on curvnet are permitted, though strongly discuouraged.
This change should have no functional impact on nooptions VIMAGE
kernel builds, where CURVNET_* macros expand to whitespace.
The curthread->td_vnet (aka curvnet) variable's purpose is to be an
indicator of the vnet context in which the current network-related
operation takes place, in case we cannot deduce the current vnet
context from any other source, such as by looking at mbuf's
m->m_pkthdr.rcvif->if_vnet, sockets's so->so_vnet etc. Moreover, so
far curvnet has turned out to be an invaluable consistency checking
aid: it helps to catch cases when sockets, ifnets or any other
vnet-aware structures may have leaked from one vnet to another.
The exact placement of the CURVNET_SET() / CURVNET_RESTORE() macros
was a result of an empirical iterative process, whith an aim to
reduce recursions on CURVNET_SET() to a minimum, while still reducing
the scope of CURVNET_SET() to networking only operations - the
alternative would be calling CURVNET_SET() on each system call entry.
In general, curvnet has to be set in three typicall cases: when
processing socket-related requests from userspace or from within the
kernel; when processing inbound traffic flowing from device drivers
to upper layers of the networking stack, and when executing
timer-driven networking functions.
This change also introduces a DDB subcommand to show the list of all
vnet instances.
Approved by: julian (mentor)
Diffstat (limited to 'sys/netgraph/netgraph.h')
-rw-r--r-- | sys/netgraph/netgraph.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/sys/netgraph/netgraph.h b/sys/netgraph/netgraph.h index e36234f..7276427 100644 --- a/sys/netgraph/netgraph.h +++ b/sys/netgraph/netgraph.h @@ -352,6 +352,7 @@ struct ng_node { LIST_ENTRY(ng_node) nd_idnodes; /* ID hash collision list */ struct ng_queue nd_input_queue; /* input queue for locking */ int nd_refs; /* # of references to this node */ + struct vnet *nd_vnet; /* network stack instance */ #ifdef NETGRAPH_DEBUG /*----------------------------------------------*/ #define ND_MAGIC 0x59264837 int nd_magic; |