nwfilter: Fix instantiated layer 2 rules for 'inout' direction

With Eric Blake's suggestions applied.

The following rule for direction 'in'

<rule direction='in' action='drop'>
  <mac srcmacaddr='1:2:3:4:5:6'/>
</rule>

drops all traffic from the given mac address.
The following rule for direction 'out'

<rule direction='out' action='drop'>
  <mac dstmacaddr='1:2:3:4:5:6'/>
</rule>

drops all traffic to the given mac address.
The following rule in direction 'inout'

<rule direction='inout' action='drop'>
  <mac srcmacaddr='1:2:3:4:5:6'/>
</rule>

now drops all traffic from and to the given MAC address.
So far it would have dropped traffic from the given MAC address
and outgoing traffic with the given source MAC address, which is not useful
since the packets will always have the VM's MAC address as source
MAC address. The attached patch fixes this.

This is the last bug I currently know of and want to fix.

src/nwfilter/nwfilter_ebiptables_driver.c

@@ -294,7 +294,8 @@ ebiptablesAddRuleInst(virNWFilterRuleInstPtr res,
 static int
 ebtablesHandleEthHdr(virBufferPtr buf,
                      virNWFilterHashTablePtr vars,
-                     ethHdrDataDefPtr ethHdr)
+                     ethHdrDataDefPtr ethHdr,
+                     bool reverse)
 {
     char macaddr[VIR_MAC_STRING_BUFLEN];
 
@@ -305,7 +306,8 @@ ebtablesHandleEthHdr(virBufferPtr buf,
             goto err_exit;
 
         virBufferVSprintf(buf,
-                      " -s %s %s",
+                      " %s %s %s",
+                      reverse ? "-d" : "-s",
                       ENTRY_GET_NEG_SIGN(&ethHdr->dataSrcMACAddr),
                       macaddr);
 
@@ -328,7 +330,8 @@ ebtablesHandleEthHdr(virBufferPtr buf,
             goto err_exit;
 
         virBufferVSprintf(buf,
-                      " -d %s %s",
+                      " %s %s %s",
+                      reverse ? "-s" : "-d",
                       ENTRY_GET_NEG_SIGN(&ethHdr->dataDstMACAddr),
                       macaddr);
 
@@ -1425,6 +1428,7 @@ iptablesCreateRuleInstance(virNWFilterDefPtr nwfilter,
  * @ifname : The name of the interface to apply the rule to
  * @vars : A map containing the variables to resolve
  * @res : The data structure to store the result(s) into
+ * @reverse : Whether to reverse src and dst attributes
  *
  * Convert a single rule into its representation for later instantiation
  *
@@ -1438,7 +1442,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                            virNWFilterRuleDefPtr rule,
                            const char *ifname,
                            virNWFilterHashTablePtr vars,
-                           virNWFilterRuleInstPtr res)
+                           virNWFilterRuleInstPtr res,
+                           bool reverse)
 {
     char macaddr[VIR_MAC_STRING_BUFLEN],
          ipaddr[INET_ADDRSTRLEN],
@@ -1464,7 +1469,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
 
         if (ebtablesHandleEthHdr(&buf,
                                  vars,
-                                 &rule->p.ethHdrFilter.ethHdr))
+                                 &rule->p.ethHdrFilter.ethHdr,
+                                 reverse))
             goto err_exit;
 
         if (HAS_ENTRY_ITEM(&rule->p.ethHdrFilter.dataProtocolID)) {
@@ -1487,7 +1493,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
 
         if (ebtablesHandleEthHdr(&buf,
                                  vars,
-                                 &rule->p.arpHdrFilter.ethHdr))
+                                 &rule->p.arpHdrFilter.ethHdr,
+                                 reverse))
             goto err_exit;
 
         virBufferAddLit(&buf, " -p arp");
@@ -1532,7 +1539,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --arp-ip-src %s %s",
+                          " %s %s %s",
+                          reverse ? "--arp-ip-dst" : "--arp-ip-src",
                           ENTRY_GET_NEG_SIGN(&rule->p.arpHdrFilter.dataARPSrcIPAddr),
                           ipaddr);
         }
@@ -1544,7 +1552,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --arp-ip-dst %s %s",
+                          " %s %s %s",
+                          reverse ? "--arp-ip-src" : "--arp-ip-dst",
                           ENTRY_GET_NEG_SIGN(&rule->p.arpHdrFilter.dataARPDstIPAddr),
                           ipaddr);
         }
@@ -1556,7 +1565,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --arp-mac-src %s %s",
+                          " %s %s %s",
+                          reverse ? "--arp-mac-dst" : "--arp-mac-src",
                           ENTRY_GET_NEG_SIGN(&rule->p.arpHdrFilter.dataARPSrcMACAddr),
                           macaddr);
         }
@@ -1568,7 +1578,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --arp-mac-dst %s %s",
+                          " %s %s %s",
+                          reverse ? "--arp-mac-src" : "--arp-mac-dst",
                           ENTRY_GET_NEG_SIGN(&rule->p.arpHdrFilter.dataARPDstMACAddr),
                           macaddr);
         }
@@ -1581,7 +1592,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
 
         if (ebtablesHandleEthHdr(&buf,
                                  vars,
-                                 &rule->p.ipHdrFilter.ethHdr))
+                                 &rule->p.ipHdrFilter.ethHdr,
+                                 reverse))
             goto err_exit;
 
         virBufferAddLit(&buf,
@@ -1594,7 +1606,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --ip-source %s %s",
+                          " %s %s %s",
+                          reverse ? "--ip-destination" : "--ip-source",
                           ENTRY_GET_NEG_SIGN(&rule->p.ipHdrFilter.ipHdr.dataSrcIPAddr),
                           ipaddr);
 
@@ -1617,7 +1630,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --ip-destination %s %s",
+                          " %s %s %s",
+                          reverse ? "--ip-source" : "--ip-destination",
                           ENTRY_GET_NEG_SIGN(&rule->p.ipHdrFilter.ipHdr.dataDstIPAddr),
                           ipaddr);
 
@@ -1652,7 +1666,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --ip-source-port %s %s",
+                          " %s %s %s",
+                          reverse ? "--ip-destination-port" : "--ip-source-port",
                           ENTRY_GET_NEG_SIGN(&rule->p.ipHdrFilter.portData.dataSrcPortStart),
                           number);
 
@@ -1676,7 +1691,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --ip-destination-port %s %s",
+                          " %s %s %s",
+                          reverse ? "--ip-source-port" : "--ip-destination-port",
                           ENTRY_GET_NEG_SIGN(&rule->p.ipHdrFilter.portData.dataDstPortStart),
                           number);
 
@@ -1712,7 +1728,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
 
         if (ebtablesHandleEthHdr(&buf,
                                  vars,
-                                 &rule->p.ipv6HdrFilter.ethHdr))
+                                 &rule->p.ipv6HdrFilter.ethHdr,
+                                 reverse))
             goto err_exit;
 
         virBufferAddLit(&buf,
@@ -1725,7 +1742,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --ip6-source %s %s",
+                          " %s %s %s",
+                          reverse ? "--ip6-destination" : "--ip6-source",
                           ENTRY_GET_NEG_SIGN(&rule->p.ipv6HdrFilter.ipHdr.dataSrcIPAddr),
                           ipv6addr);
 
@@ -1748,7 +1766,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --ip6-destination %s %s",
+                          " %s %s %s",
+                          reverse ? "--ip6-source" : "--ip6-destination",
                           ENTRY_GET_NEG_SIGN(&rule->p.ipv6HdrFilter.ipHdr.dataDstIPAddr),
                           ipv6addr);
 
@@ -1783,7 +1802,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --ip6-source-port %s %s",
+                          " %s %s %s",
+                          reverse ? "--ip6-destination-port" : "--ip6-source-port",
                           ENTRY_GET_NEG_SIGN(&rule->p.ipv6HdrFilter.portData.dataSrcPortStart),
                           number);
 
@@ -1807,7 +1827,8 @@ ebtablesCreateRuleInstance(char chainPrefix,
                 goto err_exit;
 
             virBufferVSprintf(&buf,
-                          " --ip6-destination-port %s %s",
+                          " %s %s %s",
+                          reverse ? "--ip6-source-port" : "--ip6-destination-port",
                           ENTRY_GET_NEG_SIGN(&rule->p.ipv6HdrFilter.portData.dataDstPortStart),
                           number);
 
@@ -1900,7 +1921,8 @@ ebiptablesCreateRuleInstance(virConnectPtr conn ATTRIBUTE_UNUSED,
                                             rule,
                                             ifname,
                                             vars,
-                                            res);
+                                            res,
+                                            rule->tt == VIR_NWFILTER_RULE_DIRECTION_INOUT);
             if (rc)
                 return rc;
         }
@@ -1912,7 +1934,8 @@ ebiptablesCreateRuleInstance(virConnectPtr conn ATTRIBUTE_UNUSED,
                                             rule,
                                             ifname,
                                             vars,
-                                            res);
+                                            res,
+                                            false);
         }
     break;