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27d37320ec
after the corresponding interface has been destroyed:
(1) Add an ifnet refcount, ifp->if_refcount. Initialize it to 1 in
if_alloc(), and modify if_free_type() to decrement and check the
refcount.
(2) Add new if_ref() and if_rele() interfaces to allow kernel code
walking global interface lists to release IFNET_[RW]LOCK() yet
keep the ifnet stable. Currently, if_rele() is a no-op wrapper
around if_free(), but this may change in the future.
(3) Add new ifnet field, if_alloctype, which caches the type passed
to if_alloc(), but unlike if_type, won't be changed by drivers.
This allows asynchronous free's of the interface after the
driver has released it to still use the right type. Use that
instead of the type passed to if_free_type(), but assert that
they are the same (might have to rethink this if that doesn't
work out).
(4) Add a new ifnet_byindex_ref(), which looks up an interface by
index and returns a reference rather than a pointer to it.
(5) Fix if_alloc() to fully initialize the if_addr_mtx before hooking
up the ifnet to global lists.
(6) Modify sysctls in if_mib.c to use ifnet_byindex_ref() and release
the ifnet when done.
When this change is MFC'd, it will need to replace if_ispare fields
rather than adding new fields in order to avoid breaking the binary
interface. Once this change is MFC'd, if_free_type() should be
removed, as its 'type' argument is now optional.
This refcount is not appropriate for counting mbuf pkthdr references,
and also not for counting entry into the device driver via ifnet
function pointers. An rmlock may be appropriate for the latter.
Rather, this is about ensuring data structure stability when reaching
an ifnet via global ifnet lists and tables followed by copy in or out
of userspace.
MFC after: 3 weeks
Reported by: mdtancsa
Reviewed by: brooks
175 lines
5.1 KiB
C
175 lines
5.1 KiB
C
/*-
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* Copyright 1996 Massachusetts Institute of Technology
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*
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* Permission to use, copy, modify, and distribute this software and
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* its documentation for any purpose and without fee is hereby
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* granted, provided that both the above copyright notice and this
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* permission notice appear in all copies, that both the above
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* copyright notice and this permission notice appear in all
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* supporting documentation, and that the name of M.I.T. not be used
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* in advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission. M.I.T. makes
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* no representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied
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* warranty.
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*
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* THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
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* ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
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* SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include "opt_route.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/socket.h>
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#include <sys/sysctl.h>
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#include <sys/vimage.h>
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#include <net/if.h>
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#include <net/if_mib.h>
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#include <net/route.h>
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#include <net/vnet.h>
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/*
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* A sysctl(3) MIB for generic interface information. This information
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* is exported in the net.link.generic branch, which has the following
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* structure:
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*
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* net.link.generic .system - system-wide control variables
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* and statistics (node)
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* .ifdata.<ifindex>.general
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* - what's in `struct ifdata'
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* plus some other info
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* .ifdata.<ifindex>.linkspecific
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* - a link-type-specific data
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* structure (as might be used
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* by an SNMP agent
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*
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* Perhaps someday we will make addresses accessible via this interface
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* as well (then there will be four such...). The reason that the
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* index comes before the last element in the name is because it
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* seems more orthogonal that way, particularly with the possibility
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* of other per-interface data living down here as well (e.g., integrated
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* services stuff).
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*/
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SYSCTL_DECL(_net_link_generic);
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SYSCTL_NODE(_net_link_generic, IFMIB_SYSTEM, system, CTLFLAG_RW, 0,
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"Variables global to all interfaces");
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SYSCTL_V_INT(V_NET, vnet_net, _net_link_generic_system, IFMIB_IFCOUNT,
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ifcount, CTLFLAG_RD, if_index, 0,
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"Number of configured interfaces");
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static int
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sysctl_ifdata(SYSCTL_HANDLER_ARGS) /* XXX bad syntax! */
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{
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INIT_VNET_NET(curvnet);
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int *name = (int *)arg1;
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int error;
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u_int namelen = arg2;
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struct ifnet *ifp;
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struct ifmibdata ifmd;
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size_t dlen;
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char *dbuf;
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if (namelen != 2)
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return EINVAL;
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if (name[0] <= 0)
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return (ENOENT);
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ifp = ifnet_byindex_ref(name[0]);
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if (ifp == NULL)
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return (ENOENT);
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switch(name[1]) {
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default:
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error = ENOENT;
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goto out;
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case IFDATA_GENERAL:
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bzero(&ifmd, sizeof(ifmd));
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strlcpy(ifmd.ifmd_name, ifp->if_xname, sizeof(ifmd.ifmd_name));
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#define COPY(fld) ifmd.ifmd_##fld = ifp->if_##fld
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COPY(pcount);
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COPY(data);
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#undef COPY
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ifmd.ifmd_flags = ifp->if_flags | ifp->if_drv_flags;
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ifmd.ifmd_snd_len = ifp->if_snd.ifq_len;
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ifmd.ifmd_snd_maxlen = ifp->if_snd.ifq_maxlen;
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ifmd.ifmd_snd_drops = ifp->if_snd.ifq_drops;
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error = SYSCTL_OUT(req, &ifmd, sizeof ifmd);
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if (error || !req->newptr)
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goto out;
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error = SYSCTL_IN(req, &ifmd, sizeof ifmd);
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if (error)
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goto out;
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#define DONTCOPY(fld) ifmd.ifmd_data.ifi_##fld = ifp->if_data.ifi_##fld
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DONTCOPY(type);
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DONTCOPY(physical);
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DONTCOPY(addrlen);
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DONTCOPY(hdrlen);
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DONTCOPY(mtu);
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DONTCOPY(metric);
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DONTCOPY(baudrate);
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#undef DONTCOPY
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#define COPY(fld) ifp->if_##fld = ifmd.ifmd_##fld
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COPY(data);
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ifp->if_snd.ifq_maxlen = ifmd.ifmd_snd_maxlen;
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ifp->if_snd.ifq_drops = ifmd.ifmd_snd_drops;
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#undef COPY
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break;
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case IFDATA_LINKSPECIFIC:
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error = SYSCTL_OUT(req, ifp->if_linkmib, ifp->if_linkmiblen);
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if (error || !req->newptr)
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goto out;
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error = SYSCTL_IN(req, ifp->if_linkmib, ifp->if_linkmiblen);
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if (error)
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goto out;
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break;
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case IFDATA_DRIVERNAME:
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/* 20 is enough for 64bit ints */
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dlen = strlen(ifp->if_dname) + 20 + 1;
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if ((dbuf = malloc(dlen, M_TEMP, M_NOWAIT)) == NULL) {
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error = ENOMEM;
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goto out;
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}
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if (ifp->if_dunit == IF_DUNIT_NONE)
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strcpy(dbuf, ifp->if_dname);
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else
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sprintf(dbuf, "%s%d", ifp->if_dname, ifp->if_dunit);
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error = SYSCTL_OUT(req, dbuf, strlen(dbuf) + 1);
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if (error == 0 && req->newptr != NULL)
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error = EPERM;
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free(dbuf, M_TEMP);
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goto out;
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}
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out:
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if_rele(ifp);
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return error;
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}
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SYSCTL_NODE(_net_link_generic, IFMIB_IFDATA, ifdata, CTLFLAG_RW,
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sysctl_ifdata, "Interface table");
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