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nwfilter: Instantiate comments in ip(6)tables rules
In this patch I am extending the rule instantiator to create the comment node where supported, which is the case for iptables and ip6tables. Since commands are written in the format cmd='iptables ...-m comment --comment \"\" ' certain characters ('`) in the comment need to be escaped to prevent comments from becoming commands themselves or cause other forms of (bash) substitutions. I have tested this with various input and in my tests the input made it straight into the comment. A test case for TCK will be provided separately that tests this.
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@ -23,6 +23,7 @@
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#include <config.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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@ -52,10 +53,10 @@
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#define CMD_SEPARATOR "\n"
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#define CMD_DEF_PRE "cmd=\""
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#define CMD_DEF_POST "\""
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#define CMD_DEF_PRE "cmd='"
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#define CMD_DEF_POST "'"
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#define CMD_DEF(X) CMD_DEF_PRE X CMD_DEF_POST
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#define CMD_EXEC "res=`${cmd}`" CMD_SEPARATOR
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#define CMD_EXEC "eval res=\\`\"${cmd}\"\\`" CMD_SEPARATOR
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#define CMD_STOPONERR(X) \
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X ? "if [ $? -ne 0 ]; then" \
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" echo \"Failure to execute command '${cmd}'.\";" \
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@ -106,6 +107,7 @@ static const char *m_physdev_out_str = "-m physdev " PHYSDEV_OUT;
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#define MATCH_PHYSDEV_IN m_physdev_in_str
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#define MATCH_PHYSDEV_OUT m_physdev_out_str
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#define COMMENT_VARNAME "comment"
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static int ebtablesRemoveBasicRules(const char *ifname);
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static int ebiptablesDriverInit(void);
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@ -291,6 +293,26 @@ printDataTypeAsHex(virNWFilterHashTablePtr vars,
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}
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static void
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printCommentVar(virBufferPtr dest, const char *buf)
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{
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size_t i, len = strlen(buf);
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virBufferAddLit(dest, COMMENT_VARNAME "='");
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if (len > IPTABLES_MAX_COMMENT_LENGTH)
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len = IPTABLES_MAX_COMMENT_LENGTH;
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for (i = 0; i < len; i++) {
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if (buf[i] == '\'')
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virBufferAddLit(dest, "'\\''");
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else
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virBufferAddChar(dest, buf[i]);
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}
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virBufferAddLit(dest,"'" CMD_SEPARATOR);
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}
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static void
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ebiptablesRuleInstFree(ebiptablesRuleInstPtr inst)
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{
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@ -846,7 +868,8 @@ iptablesHandleIpHdr(virBufferPtr buf,
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virNWFilterHashTablePtr vars,
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ipHdrDataDefPtr ipHdr,
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int directionIn,
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bool *skipRule, bool *skipMatch)
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bool *skipRule, bool *skipMatch,
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virBufferPtr prefix)
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{
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char ipaddr[INET6_ADDRSTRLEN],
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number[20];
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@ -993,6 +1016,13 @@ iptablesHandleIpHdr(virBufferPtr buf,
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}
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}
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if (HAS_ENTRY_ITEM(&ipHdr->dataComment)) {
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printCommentVar(prefix, ipHdr->dataComment.u.string);
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virBufferAddLit(buf,
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" -m comment --comment \"$" COMMENT_VARNAME "\"");
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}
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return 0;
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err_exit:
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@ -1106,7 +1136,9 @@ _iptablesCreateRuleInstance(int directionIn,
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{
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char chain[MAX_CHAINNAME_LENGTH];
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char number[20];
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virBuffer prefix = VIR_BUFFER_INITIALIZER;
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virBuffer buf = VIR_BUFFER_INITIALIZER;
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virBufferPtr final = NULL;
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const char *target;
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const char *iptables_cmd = (isIPv6) ? ip6tables_cmd_path
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: iptables_cmd_path;
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@ -1148,7 +1180,8 @@ _iptablesCreateRuleInstance(int directionIn,
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vars,
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&rule->p.tcpHdrFilter.ipHdr,
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directionIn,
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&skipRule, &skipMatch))
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&skipRule, &skipMatch,
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&prefix))
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goto err_exit;
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if (iptablesHandlePortData(&buf,
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@ -1193,7 +1226,8 @@ _iptablesCreateRuleInstance(int directionIn,
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vars,
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&rule->p.udpHdrFilter.ipHdr,
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directionIn,
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&skipRule, &skipMatch))
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&skipRule, &skipMatch,
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&prefix))
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goto err_exit;
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if (iptablesHandlePortData(&buf,
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@ -1225,7 +1259,8 @@ _iptablesCreateRuleInstance(int directionIn,
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vars,
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&rule->p.udpliteHdrFilter.ipHdr,
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directionIn,
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&skipRule, &skipMatch))
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&skipRule, &skipMatch,
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&prefix))
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goto err_exit;
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break;
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@ -1252,7 +1287,8 @@ _iptablesCreateRuleInstance(int directionIn,
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vars,
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&rule->p.espHdrFilter.ipHdr,
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directionIn,
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&skipRule, &skipMatch))
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&skipRule, &skipMatch,
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&prefix))
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goto err_exit;
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break;
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@ -1279,7 +1315,8 @@ _iptablesCreateRuleInstance(int directionIn,
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vars,
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&rule->p.ahHdrFilter.ipHdr,
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directionIn,
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&skipRule, &skipMatch))
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&skipRule, &skipMatch,
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&prefix))
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goto err_exit;
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break;
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@ -1306,7 +1343,8 @@ _iptablesCreateRuleInstance(int directionIn,
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vars,
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&rule->p.sctpHdrFilter.ipHdr,
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directionIn,
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&skipRule, &skipMatch))
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&skipRule, &skipMatch,
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&prefix))
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goto err_exit;
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if (iptablesHandlePortData(&buf,
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@ -1341,7 +1379,8 @@ _iptablesCreateRuleInstance(int directionIn,
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vars,
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&rule->p.icmpHdrFilter.ipHdr,
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directionIn,
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&skipRule, &skipMatch))
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&skipRule, &skipMatch,
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&prefix))
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goto err_exit;
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if (HAS_ENTRY_ITEM(&rule->p.icmpHdrFilter.dataICMPType)) {
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@ -1400,7 +1439,8 @@ _iptablesCreateRuleInstance(int directionIn,
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vars,
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&rule->p.igmpHdrFilter.ipHdr,
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directionIn,
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&skipRule, &skipMatch))
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&skipRule, &skipMatch,
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&prefix))
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goto err_exit;
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break;
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@ -1427,7 +1467,8 @@ _iptablesCreateRuleInstance(int directionIn,
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vars,
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&rule->p.allHdrFilter.ipHdr,
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directionIn,
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&skipRule, &skipMatch))
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&skipRule, &skipMatch,
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&prefix))
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goto err_exit;
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break;
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@ -1439,6 +1480,7 @@ _iptablesCreateRuleInstance(int directionIn,
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if ((srcMacSkipped && bufUsed == virBufferUse(&buf)) ||
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skipRule) {
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virBufferFreeAndReset(&buf);
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virBufferFreeAndReset(&prefix);
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return 0;
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}
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@ -1458,14 +1500,29 @@ _iptablesCreateRuleInstance(int directionIn,
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CMD_EXEC,
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target);
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if (virBufferError(&buf)) {
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if (virBufferError(&buf) || virBufferError(&prefix)) {
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virBufferFreeAndReset(&buf);
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virBufferFreeAndReset(&prefix);
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virReportOOMError();
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return -1;
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}
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if (virBufferUse(&prefix)) {
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virBufferVSprintf(&prefix, "%s", virBufferContentAndReset(&buf));
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final = &prefix;
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if (virBufferError(&prefix)) {
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virBufferFreeAndReset(&prefix);
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virReportOOMError();
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return -1;
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}
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} else
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final = &buf;
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return ebiptablesAddRuleInst(res,
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virBufferContentAndReset(&buf),
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virBufferContentAndReset(final),
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nwfilter->chainsuffix,
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'\0',
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rule->priority,
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@ -45,4 +45,6 @@ extern virNWFilterTechDriver ebiptables_driver;
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# define EBIPTABLES_DRIVER_ID "ebiptables"
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# define IPTABLES_MAX_COMMENT_LENGTH 256
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#endif
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