[libvirt] [PATCH v2 1/2] nwfilter: fix IP address learning

[Daniel P. Berrangé]

In a previous commit:

  commit d4bf8f415074759baf051644559e04fe78888f8b
  Author: Daniel P. Berrangé <berrange at redhat.com>
  Date:   Wed Feb 14 09:43:59 2018 +0000

    nwfilter: handle missing switch enum cases

    Ensure all enum cases are listed in switch statements, or cast away
    enum type in places where we don't wish to cover all cases.

    Reviewed-by: John Ferlan <jferlan at redhat.com>
    Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>

we changed a switch in the nwfilter learning thread so that it had
explict cases for all enum entries. Unfortunately the parameters in the
method had been declared with incorrect type. The "howDetect" parameter
does *not* accept "enum howDetect" values, rather it accepts a bitmask
of "enum howDetect" values, so it should have been an "int" type.

The caller always passes DETECT_STATIC|DETECT_DHCP, so essentially the
IP addressing learning was completely broken by the above change, as it
never matched any switch case, hitting the default leading to EINVAL.

Stop using a typedef for the parameter name this this is a bitmask,
not a plain enum value. Also stop using switch() since that's misleading
with bitmasks too.

Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
---
 src/nwfilter/nwfilter_learnipaddr.c | 18 +++++++-----------
 src/nwfilter/nwfilter_learnipaddr.h |  2 +-
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/src/nwfilter/nwfilter_learnipaddr.c b/src/nwfilter/nwfilter_learnipaddr.c
index cc3bfd971c..085af7892e 100644
--- a/src/nwfilter/nwfilter_learnipaddr.c
+++ b/src/nwfilter/nwfilter_learnipaddr.c
@@ -144,7 +144,7 @@ struct _virNWFilterIPAddrLearnReq {
     char *filtername;
     virHashTablePtr filterparams;
     virNWFilterDriverStatePtr driver;
-    enum howDetect howDetect;
+    int howDetect; /* bitmask of enum howDetect */
 
     int status;
     volatile bool terminate;
@@ -437,28 +437,24 @@ learnIPAddressThread(void *arg)
 
     virMacAddrFormat(&req->macaddr, macaddr);
 
-    switch (req->howDetect) {
-    case DETECT_DHCP:
+    if (req->howDetect == DETECT_DHCP) {
         if (techdriver->applyDHCPOnlyRules(req->ifname,
                                            &req->macaddr,
                                            NULL, false) < 0) {
+            VIR_DEBUG("Unable to apply DHCP only rules");
             req->status = EINVAL;
             goto done;
         }
         virBufferAddLit(&buf, "src port 67 and dst port 68");
-        break;
-    case DETECT_STATIC:
+    } else {
         if (techdriver->applyBasicRules(req->ifname,
                                         &req->macaddr) < 0) {
+            VIR_DEBUG("Unable to apply basic rules");
             req->status = EINVAL;
             goto done;
         }
         virBufferAsprintf(&buf, "ether host %s or ether dst ff:ff:ff:ff:ff:ff",
                           macaddr);
-        break;
-    default:
-        req->status = EINVAL;
-        goto done;
     }
 
     if (virBufferError(&buf)) {
@@ -693,7 +689,7 @@ learnIPAddressThread(void *arg)
  *               once its IP address has been detected
  * @driver : the network filter driver
  * @howDetect : the method on how the thread is supposed to detect the
- *              IP address; must choose any of the available flags
+ *              IP address; bitmask of "enum howDetect" flags.
  *
  * Instruct to learn the IP address being used on a given interface (ifname).
  * Unless there already is a thread attempting to learn the IP address
@@ -711,7 +707,7 @@ virNWFilterLearnIPAddress(virNWFilterTechDriverPtr techdriver,
                           const char *filtername,
                           virHashTablePtr filterparams,
                           virNWFilterDriverStatePtr driver,
-                          enum howDetect howDetect)
+                          int howDetect)
 {
     int rc;
     virThread thread;
diff --git a/src/nwfilter/nwfilter_learnipaddr.h b/src/nwfilter/nwfilter_learnipaddr.h
index 06fea5bff8..753aabc594 100644
--- a/src/nwfilter/nwfilter_learnipaddr.h
+++ b/src/nwfilter/nwfilter_learnipaddr.h
@@ -43,7 +43,7 @@ int virNWFilterLearnIPAddress(virNWFilterTechDriverPtr techdriver,
                               const char *filtername,
                               virHashTablePtr filterparams,
                               virNWFilterDriverStatePtr driver,
-                              enum howDetect howDetect);
+                              int howDetect);
 
 bool virNWFilterHasLearnReq(int ifindex);
 int virNWFilterTerminateLearnReq(const char *ifname);
-- 
2.17.0