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nwfilter: Add multiple IP address support to DHCP snooping

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With support for multiple IP addresses per interface in place, this patch
now adds support for multiple IP addresses per interface for the DHCP
snooping code.


Testing:

Since the infrastructure I tested this with does not provide multiple IP
addresses per MAC address (anymore), I either had to plug the VM's interface
from the virtual bride connected directly to the infrastructure to virbr0
to get a 2nd IP address from dnsmasq (kill and run dhclient inside the VM)
or changed the lease file  (/var/run/libvirt/network/nwfilter.leases) and
restart libvirtd to have a 2nd IP address on an existing interface.
Note that dnsmasq can take a lease timeout parameter as part of the --dhcp-range
command line parameter, so that timeouts can be tested that way
(--dhcp-range 192.168.122.2,192.168.122.254,120). So, terminating and restarting
dnsmasq with that parameter is another choice to watch an IP address disappear
after 120 seconds.

Regards,
   Stefan
This commit is contained in:
Stefan Berger 2012-06-01 19:32:06 -04:00 committed by Stefan Berger
parent 797b47580a
commit b92d52d3c0
1 changed files with 68 additions and 41 deletions
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109
src/nwfilter/nwfilter_dhcpsnoop.c
View File

@ -59,6 +59,7 @@
#include "conf/domain_conf.h"
#include "nwfilter_gentech_driver.h"
#include "nwfilter_dhcpsnoop.h"
#include "nwfilter_ipaddrmap.h"
#include "virnetdev.h"
#include "virfile.h"
#include "viratomic.h"
@ -277,7 +278,8 @@ struct _virNWFilterSnoopPcapConf {
/* local function prototypes */
static int virNWFilterSnoopReqLeaseDel(virNWFilterSnoopReqPtr req,
virSocketAddrPtr ipaddr,
bool update_leasefile);
bool update_leasefile,
bool instantiate);
static void virNWFilterSnoopReqLock(virNWFilterSnoopReqPtr req);
static void virNWFilterSnoopReqUnlock(virNWFilterSnoopReqPtr req);
@ -452,32 +454,22 @@ virNWFilterSnoopIPLeaseInstallRule(virNWFilterSnoopIPLeasePtr ipl,
{
char *ipaddr;
int rc = -1;
virNWFilterVarValuePtr ipVar;
virNWFilterSnoopReqPtr req;
ipaddr = virSocketAddrFormat(&ipl->ipAddress);
if (!ipaddr)
return -1;
ipVar = virNWFilterVarValueCreateSimple(ipaddr);
if (!ipVar)
goto cleanup;
ipaddr = NULL; /* belongs to ipVar now */
req = ipl->snoopReq;
/* protect req->ifname and req->vars */
/* protect req->ifname */
virNWFilterSnoopReqLock(req);
if (virNWFilterHashTablePut(req->vars, NWFILTER_VARNAME_IP,
ipVar, 1) < 0) {
virNWFilterReportError(VIR_ERR_INTERNAL_ERROR,
_("Could not add variable \""
NWFILTER_VARNAME_IP "\" to hashmap"));
virNWFilterVarValueFree(ipVar);
if (virNWFilterIPAddrMapAddIPAddr(req->ifname, ipaddr) < 0)
goto exit_snooprequnlock;
}
/* ipaddr now belongs to the map */
ipaddr = NULL;
if (!instantiate) {
rc = 0;
@ -500,7 +492,6 @@ virNWFilterSnoopIPLeaseInstallRule(virNWFilterSnoopIPLeasePtr ipl,
exit_snooprequnlock:
virNWFilterSnoopReqUnlock(req);
cleanup:
VIR_FREE(ipaddr);
return rc;
@ -543,12 +534,18 @@ static unsigned int
virNWFilterSnoopReqLeaseTimerRun(virNWFilterSnoopReqPtr req)
{
time_t now = time(0);
bool is_last = false;
/* protect req->start */
virNWFilterSnoopReqLock(req);
while (req->start && req->start->timeout <= now)
virNWFilterSnoopReqLeaseDel(req, &req->start->ipAddress, true);
while (req->start && req->start->timeout <= now) {
if (req->start->next == NULL ||
req->start->next->timeout > now)
is_last = true;
virNWFilterSnoopReqLeaseDel(req, &req->start->ipAddress, true,
is_last);
}
virNWFilterSnoopReqUnlock(req);
@ -629,7 +626,7 @@ virNWFilterSnoopReqFree(virNWFilterSnoopReqPtr req)
/* free all leases */
for (ipl = req->start; ipl; ipl = req->start)
virNWFilterSnoopReqLeaseDel(req, &ipl->ipAddress, false);
virNWFilterSnoopReqLeaseDel(req, &ipl->ipAddress, false, false);
/* free all req data */
VIR_FREE(req->ifname);
@ -763,15 +760,6 @@ virNWFilterSnoopReqLeaseAdd(virNWFilterSnoopReqPtr req,
virNWFilterSnoopReqUnlock(req);
/* support for multiple addresses requires the ability to add filters
* to existing chains, or to instantiate address lists via
* virNWFilterInstantiateFilterLate(). Until one of those capabilities
* is added, don't allow a new address when one is already assigned to
* this interface.
*/
if (req->start)
return 0; /* silently ignore multiple addresses */
if (VIR_ALLOC(pl) < 0) {
virReportOOMError();
return -1;
@ -839,34 +827,62 @@ virNWFilterSnoopReqRestore(virNWFilterSnoopReqPtr req)
* memory or when calling this function while reading
* leases from the file.
*
* @instantiate: when calling this function in a loop, indicate
* the last call with 'true' here so that the
* rules all get instantiated
* Always calling this with 'true' is fine, but less
* efficient.
*
* Returns 0 on success, -1 if the instantiation of the rules failed
*/
static int
virNWFilterSnoopReqLeaseDel(virNWFilterSnoopReqPtr req,
virSocketAddrPtr ipaddr, bool update_leasefile)
virSocketAddrPtr ipaddr, bool update_leasefile,
bool instantiate)
{
int ret = 0;
virNWFilterSnoopIPLeasePtr ipl;
char *ipstr = NULL;
int ipAddrLeft;
/* protect req->start & req->ifname */
/* protect req->start, req->ifname and the lease */
virNWFilterSnoopReqLock(req);
ipl = virNWFilterSnoopIPLeaseGetByIP(req->start, ipaddr);
if (ipl == NULL)
goto lease_not_found;
virNWFilterSnoopIPLeaseTimerDel(ipl);
ipstr = virSocketAddrFormat(&ipl->ipAddress);
if (!ipstr) {
ret = -1;
goto lease_not_found;
}
if (update_leasefile) {
virNWFilterSnoopIPLeaseTimerDel(ipl);
/* lease is off the list now */
if (update_leasefile)
virNWFilterSnoopLeaseFileSave(ipl);
ipAddrLeft = virNWFilterIPAddrMapDelIPAddr(req->ifname, ipstr);
if (!req->threadkey || !instantiate)
goto skip_instantiate;
if (ipAddrLeft) {
ret = virNWFilterInstantiateFilterLate(NULL,
req->ifname,
req->ifindex,
req->linkdev,
req->nettype,
req->macaddr,
req->filtername,
req->vars,
req->driver);
} else {
const virNWFilterVarValuePtr dhcpsrvrs =
virHashLookup(req->vars->hashTable, NWFILTER_VARNAME_DHCPSERVER);
virNWFilterSnoopLeaseFileSave(ipl);
/*
* for multiple address support, this needs to remove those rules
* referencing "IP" with ipl's ip value.
*/
if (req->techdriver &&
req->techdriver->applyDHCPOnlyRules(req->ifname, req->macaddr,
dhcpsrvrs, false) < 0) {
@ -876,11 +892,15 @@ virNWFilterSnoopReqLeaseDel(virNWFilterSnoopReqPtr req,
}
}
skip_instantiate:
VIR_FREE(ipl);
virAtomicIntDec(&virNWFilterSnoopState.nLeases);
lease_not_found:
VIR_FREE(ipstr);
virNWFilterSnoopReqUnlock(req);
return ret;
@ -1030,7 +1050,7 @@ virNWFilterSnoopDHCPDecode(virNWFilterSnoopReqPtr req,
break;
case DHCPDECLINE:
case DHCPRELEASE:
if (virNWFilterSnoopReqLeaseDel(req, &ipl.ipAddress, true) < 0)
if (virNWFilterSnoopReqLeaseDel(req, &ipl.ipAddress, true, true) < 0)
return -1;
break;
default:
@ -1954,7 +1974,7 @@ virNWFilterSnoopLeaseFileLoad(void)
if (ipl.timeout)
virNWFilterSnoopReqLeaseAdd(req, &ipl, false);
else
virNWFilterSnoopReqLeaseDel(req, &ipl.ipAddress, false);
virNWFilterSnoopReqLeaseDel(req, &ipl.ipAddress, false, false);
virNWFilterSnoopReqPut(req);
}
@ -2000,6 +2020,13 @@ virNWFilterSnoopRemAllReqIter(const void *payload,
ignore_value(virHashRemoveEntry(virNWFilterSnoopState.ifnameToKey,
req->ifname));
/*
* Remove all IP addresses known to be associated with this
* interface so that a new thread will be started on this
* interface
*/
virNWFilterIPAddrMapDelIPAddr(req->ifname, NULL);
VIR_FREE(req->ifname);
}