[libvirt] [PATCH V2 00/10] Make inner workings of nwfilters more flexible + extensions
The following series of patches re-does some of the inner workings of nwfilters with the goal to enable users to write filters that have other than the system-known chains supported right now ('root','arp','rarp','ipv4' and 'ipv6'). Ideally users should be able to provide a chain name in the chains XML attribute and either be able to jump to it as an 'action' or have the chain created automatically as it is the case right now for those chains enumerated before. The latter is now added in this patch series as well. I am first introducing internal priorities for the chains mentioned above so that their creation can be made more flexible -- currently their creation and the order in which they are accessed is hardcoded. This largely does away with the hardcoded stuff. All assigned priorities have negative values. Later on the priorities for the chains are made accessible via an XML attribute. Further, filters will be automatically accessed from the (ebtables) interface 'root' chain using the prefix of the name of the chain. As an example, the following filter will be accessed from the root chain for 'arp' packets since its name 'arp-xyz' has the prefix 'arp'. <filter name='test-arp-xyz' chain='arp-xyz' priority='-650'> <uuid>94abeecc-c956-0ac8-1f49-a06ee8995688</uuid> <rule action='accept' direction='out' priority='100'> <arp opcode='Request_Reverse' arpsrcmacaddr='$MAC' arpdstmacaddr='$MAC' arpsrcipaddr='0.0.0.0' arpdstipaddr='0.0.0.0'/> </rule> <rule action='accept' direction='inout' priority='500'/> </filter> In another step the priorities of rules is extended to also allow negativ values. This then allows the creation of rules and chains in the interface 'root' chain to be mixed so that the following layout becomes possible: Bridge chain: libvirt-I-vnet0, entries: 6, policy: ACCEPT -p IPv4 -j I-vnet0-ipv4 -p ARP -j I-vnet0-arp -p ARP -j ACCEPT -p 0x8035 -j I-vnet0-rarp -p 0x835 -j ACCEPT -j DROP In the above list of rules the '-p ARP -j ACCEPT' can now be found in between the 'jumps' to protocol-specific chains, which allows for more efficient rule evaluation. I did testing with the test cases in libvirt-tck as well as those in the tests/ directory and did not see any regressions. Regards, Stefan
Add a function to the virHashTable for getting an array of the hash table's keys and have the keys (optionally) sorted. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- src/libvirt_private.syms | 3 + src/util/hash.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++ src/util/hash.h | 14 ++++++ 3 files changed, 115 insertions(+) Index: libvirt-acl/src/util/hash.c =================================================================== --- libvirt-acl.orig/src/util/hash.c +++ libvirt-acl/src/util/hash.c @@ -618,3 +618,101 @@ void *virHashSearch(virHashTablePtr tabl return NULL; } + + +struct getKeysIter +{ + virHashTablePtr table; + void **array; + virHashKeyValuePair *sortArray; + unsigned arrayIdx; + bool error; +}; + +static void virHashGetKeysIterator(void *payload, + const void *name, void *data) +{ + struct getKeysIter *iter = data; + void *key; + + if (iter->error) + return; + + key = iter->table->keyCopy(name); + + if (key == NULL) { + virReportOOMError(); + iter->error = true; + return; + } + + if (iter->sortArray) { + iter->sortArray[iter->arrayIdx].key = key; + iter->sortArray[iter->arrayIdx].value = payload; + } else { + iter->array[iter->arrayIdx] = iter->table->keyCopy(name); + } + iter->arrayIdx++; +} + +void virHashFreeKeys(virHashTablePtr table, void **keys) +{ + unsigned i = 0; + + if (keys == NULL) + return; + + while (keys[i]) + table->keyFree(keys[i++]); + + VIR_FREE(keys); +} + +typedef int (*qsort_comp)(const void *, const void *); + +void **virHashGetKeys(virHashTablePtr table, + virHashKeyComparator compar) +{ + int i, numElems = virHashSize(table); + struct getKeysIter iter = { + .table = table, + .arrayIdx = 0, + .error = false, + }; + + if (numElems < 0) { + return NULL; + } + + if (VIR_ALLOC_N(iter.array, numElems + 1)) { + virReportOOMError(); + return NULL; + } + + /* null-terminate array */ + iter.array[numElems] = NULL; + + if (compar && + VIR_ALLOC_N(iter.sortArray, numElems)) { + VIR_FREE(iter.array); + virReportOOMError(); + return NULL; + } + + virHashForEach(table, virHashGetKeysIterator, &iter); + if (iter.error) { + VIR_FREE(iter.sortArray); + virHashFreeKeys(table, iter.array); + return NULL; + } + + if (compar) { + qsort(&iter.sortArray[0], numElems, sizeof(iter.sortArray[0]), + (qsort_comp)compar); + for (i = 0; i < numElems; i++) + iter.array[i] = iter.sortArray[i].key; + VIR_FREE(iter.sortArray); + } + + return iter.array; +} Index: libvirt-acl/src/util/hash.h =================================================================== --- libvirt-acl.orig/src/util/hash.h +++ libvirt-acl/src/util/hash.h @@ -130,6 +130,20 @@ void *virHashLookup(virHashTablePtr tabl */ void *virHashSteal(virHashTablePtr table, const void *name); +/* + * Get the set of keys and have them optionally sorted. + */ +typedef struct _virHashKeyValuePair virHashKeyValuePair; +typedef virHashKeyValuePair *virHashKeyValuePairPtr; +struct _virHashKeyValuePair { + void *key; + const void *value; +}; +typedef int (*virHashKeyComparator)(const virHashKeyValuePairPtr , + const virHashKeyValuePairPtr ); +void **virHashGetKeys(virHashTablePtr table, virHashKeyComparator compar); +void virHashFreeKeys(virHashTablePtr table, void **); + /* * Iterators Index: libvirt-acl/src/libvirt_private.syms =================================================================== --- libvirt-acl.orig/src/libvirt_private.syms +++ libvirt-acl/src/libvirt_private.syms @@ -552,6 +552,8 @@ virHashAddEntry; virHashCreate; virHashForEach; virHashFree; +virHashFreeKeys; +virHashGetKeys; virHashLookup; virHashRemoveEntry; virHashRemoveSet; @@ -559,6 +561,7 @@ virHashSearch; virHashSize; virHashSteal; virHashTableSize; +virHashUpdateEntry; # hooks.h
For better handling of the sorting of chains introduce an internally used priority. Use a lookup table to store the priorities. For now their actual values do not matter just that the values cause the chains to be properly sorted through changes in the following patches. However, the values are chosen as negative so that once they are sorted along with filtering rules (whose priority may only be positive for now) they will always be instantiated before them (lower values cause instantiation before higher values). This is done to maintain backwards compatibility. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- src/conf/nwfilter_conf.c | 14 ++++++++++++++ src/conf/nwfilter_conf.h | 12 ++++++++++++ src/nwfilter/nwfilter_ebiptables_driver.c | 4 ++++ src/nwfilter/nwfilter_ebiptables_driver.h | 1 + 4 files changed, 31 insertions(+) Index: libvirt-acl/src/conf/nwfilter_conf.h =================================================================== --- libvirt-acl.orig/src/conf/nwfilter_conf.h +++ libvirt-acl/src/conf/nwfilter_conf.h @@ -355,8 +355,18 @@ enum virNWFilterEbtablesTableType { }; +# define MIN_RULE_PRIORITY 0 # define MAX_RULE_PRIORITY 1000 +# define NWFILTER_MIN_FILTER_PRIORITY -1000 +# define NWFILTER_MAX_FILTER_PRIORITY MAX_RULE_PRIORITY + +# define NWFILTER_ROOT_FILTER_PRI 0 +# define NWFILTER_IPV4_FILTER_PRI -900 +# define NWFILTER_IPV6_FILTER_PRI -800 +# define NWFILTER_ARP_FILTER_PRI -700 +# define NWFILTER_RARP_FILTER_PRI -600 + enum virNWFilterRuleFlags { RULE_FLAG_NO_STATEMATCH = (1 << 0), RULE_FLAG_STATE_NEW = (1 << 1), @@ -434,6 +444,7 @@ enum virNWFilterChainSuffixType { VIR_NWFILTER_CHAINSUFFIX_LAST, }; +typedef int32_t virNWFilterChainPriority; typedef struct _virNWFilterDef virNWFilterDef; typedef virNWFilterDef *virNWFilterDefPtr; @@ -443,6 +454,7 @@ struct _virNWFilterDef { unsigned char uuid[VIR_UUID_BUFLEN]; int chainsuffix; /*enum virNWFilterChainSuffixType */ + virNWFilterChainPriority chainPriority; int nentries; virNWFilterEntryPtr *filterEntries; Index: libvirt-acl/src/conf/nwfilter_conf.c =================================================================== --- libvirt-acl.orig/src/conf/nwfilter_conf.c +++ libvirt-acl/src/conf/nwfilter_conf.c @@ -120,6 +120,14 @@ struct int_map { #define INTMAP_ENTRY(ATT, VAL) { .attr = ATT, .val = VAL } #define INTMAP_ENTRY_LAST { .val = NULL } +static const struct int_map chain_priorities[] = { + INTMAP_ENTRY(NWFILTER_ROOT_FILTER_PRI, "root"), + INTMAP_ENTRY(NWFILTER_IPV4_FILTER_PRI, "ipv4"), + INTMAP_ENTRY(NWFILTER_IPV6_FILTER_PRI, "ipv6"), + INTMAP_ENTRY(NWFILTER_ARP_FILTER_PRI , "arp" ), + INTMAP_ENTRY(NWFILTER_RARP_FILTER_PRI, "rarp"), + INTMAP_ENTRY_LAST, +}; /* * only one filter update allowed @@ -2026,6 +2034,12 @@ virNWFilterDefParseXML(xmlXPathContextPt _("unknown chain suffix '%s'"), chain); goto cleanup; } + /* assign an implicit priority -- support XML attribute later */ + if (intMapGetByString(chain_priorities, chain, 0, + &ret->chainPriority) == false) { + ret->chainPriority = (NWFILTER_MAX_FILTER_PRIORITY + + NWFILTER_MIN_FILTER_PRIORITY) / 2; + } } uuid = virXPathString("string(./uuid)", ctxt); Index: libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.h =================================================================== --- libvirt-acl.orig/src/nwfilter/nwfilter_ebiptables_driver.h +++ libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.h @@ -36,6 +36,7 @@ typedef ebiptablesRuleInst *ebiptablesRu struct _ebiptablesRuleInst { char *commandTemplate; enum virNWFilterChainSuffixType neededProtocolChain; + virNWFilterChainPriority chainPriority; char chainprefix; /* I for incoming, O for outgoing */ unsigned int priority; enum RuleType ruleType; Index: libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c =================================================================== --- libvirt-acl.orig/src/nwfilter/nwfilter_ebiptables_driver.c +++ libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c @@ -327,6 +327,7 @@ static int ebiptablesAddRuleInst(virNWFilterRuleInstPtr res, char *commandTemplate, enum virNWFilterChainSuffixType neededChain, + virNWFilterChainPriority chainPriority, char chainprefix, unsigned int priority, enum RuleType ruleType) @@ -340,6 +341,7 @@ ebiptablesAddRuleInst(virNWFilterRuleIns inst->commandTemplate = commandTemplate; inst->neededProtocolChain = neededChain; + inst->chainPriority = chainPriority; inst->chainprefix = chainprefix; inst->priority = priority; inst->ruleType = ruleType; @@ -1588,6 +1590,7 @@ _iptablesCreateRuleInstance(int directio return ebiptablesAddRuleInst(res, virBufferContentAndReset(final), nwfilter->chainsuffix, + nwfilter->chainPriority, '\0', rule->priority, (isIPv6) ? RT_IP6TABLES : RT_IPTABLES); @@ -2337,6 +2340,7 @@ ebtablesCreateRuleInstance(char chainPre return ebiptablesAddRuleInst(res, virBufferContentAndReset(&buf), nwfilter->chainsuffix, + nwfilter->chainPriority, chainPrefix, rule->priority, RT_EBTABLES);
Use the previously introduced chain priorities to sort the chains for access from an interface's 'root' table and have them created in the proper order. This gets rid of a lot of code that was previously creating the chains in a more hardcoded way. To determine what protocol a filter is used for evaluation do prefix- matching, i.e., the filter 'arp' is used to filter for the 'arp' protocol, 'ipv4' for the 'ipv4' protocol and 'arp-xyz' will also be used to filter for the 'arp' protocol following the prefix 'arp' in its name. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- src/nwfilter/nwfilter_ebiptables_driver.c | 130 ++++++++++++++++++++++-------- 1 file changed, 98 insertions(+), 32 deletions(-) Index: libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c =================================================================== --- libvirt-acl.orig/src/nwfilter/nwfilter_ebiptables_driver.c +++ libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c @@ -2774,6 +2774,7 @@ ebtablesCreateTmpSubChain(virBufferPtr b int incoming, const char *ifname, enum l3_proto_idx protoidx, + const char *filtername, int stopOnError) { char rootchain[MAX_CHAINNAME_LENGTH], chain[MAX_CHAINNAME_LENGTH]; @@ -2781,7 +2782,8 @@ ebtablesCreateTmpSubChain(virBufferPtr b : CHAINPREFIX_HOST_OUT_TEMP; PRINT_ROOT_CHAIN(rootchain, chainPrefix, ifname); - PRINT_CHAIN(chain, chainPrefix, ifname, l3_protocols[protoidx].val); + PRINT_CHAIN(chain, chainPrefix, ifname, + (filtername) ? filtername : l3_protocols[protoidx].val); virBufferAsprintf(buf, CMD_DEF("%s -t %s -N %s") CMD_SEPARATOR @@ -3288,6 +3290,13 @@ ebiptablesRuleOrderSort(const void *a, c return ((*insta)->priority - (*instb)->priority); } +static int +ebiptablesFilterOrderSort(const virHashKeyValuePairPtr a, + const virHashKeyValuePairPtr b) +{ + return *(virNWFilterChainPriority *)a->value - + *(virNWFilterChainPriority *)b->value; +} static void iptablesCheckBridgeNFCallEnabled(bool isIPv6) @@ -3327,6 +3336,56 @@ iptablesCheckBridgeNFCallEnabled(bool is } } +/* + * Given a filtername determine the protocol it is used for evaluating + * We do prefix-matching to determine the protocol. + */ +static enum l3_proto_idx +ebtablesGetProtoIdxByFiltername(const char *filtername) +{ + enum l3_proto_idx idx; + + for (idx = 0; idx < L3_PROTO_LAST_IDX; idx++) { + if (STRPREFIX(filtername, l3_protocols[idx].val)) { + return idx; + } + } + + return -1; +} + +static int +ebtablesCreateTmpRootAndSubChains(virBufferPtr buf, + const char *ifname, + virHashTablePtr chains, int direction) +{ + int rc = 0, i; + + if (virHashSize(chains) != 0) { + char **filter_names; + + ebtablesCreateTmpRootChain(buf, direction, ifname, 1); + filter_names = (char **)virHashGetKeys(chains, + ebiptablesFilterOrderSort); + if (filter_names == NULL) { + virReportOOMError(); + rc = 1; + goto err_exit; + } + for (i = 0; filter_names[i]; i++) { + enum l3_proto_idx idx = ebtablesGetProtoIdxByFiltername( + filter_names[i]); + if ((int)idx < 0) + continue; + ebtablesCreateTmpSubChain(buf, direction, ifname, idx, + filter_names[i], 1); + } + virHashFreeKeys(chains, (void **)filter_names); + } + + err_exit: + return rc; +} static int ebiptablesApplyNewRules(virConnectPtr conn ATTRIBUTE_UNUSED, @@ -3337,24 +3396,43 @@ ebiptablesApplyNewRules(virConnectPtr co int i; int cli_status; ebiptablesRuleInstPtr *inst = (ebiptablesRuleInstPtr *)_inst; - int chains_in = 0, chains_out = 0; virBuffer buf = VIR_BUFFER_INITIALIZER; + virHashTablePtr chains_in_set = virHashCreate(10, NULL), + chains_out_set = virHashCreate(10, NULL); bool haveIptables = false; bool haveIp6tables = false; + if (!chains_in_set || !chains_out_set) { + virReportOOMError(); + goto exit_free_sets; + } + if (nruleInstances > 1 && inst) qsort(inst, nruleInstances, sizeof(inst[0]), ebiptablesRuleOrderSort); + /* scan the rules to see which chains need to be created */ for (i = 0; i < nruleInstances; i++) { sa_assert (inst); if (inst[i]->ruleType == RT_EBTABLES) { - if (inst[i]->chainprefix == CHAINPREFIX_HOST_IN_TEMP) - chains_in |= (1 << inst[i]->neededProtocolChain); - else - chains_out |= (1 << inst[i]->neededProtocolChain); + const char *name = virNWFilterChainSuffixTypeToString( + inst[i]->neededProtocolChain); + if (inst[i]->chainprefix == CHAINPREFIX_HOST_IN_TEMP) { + if (virHashUpdateEntry(chains_in_set, name, + &inst[i]->chainPriority)) { + virReportOOMError(); + goto exit_free_sets; + } + } else { + if (virHashUpdateEntry(chains_out_set, name, + &inst[i]->chainPriority)) { + virReportOOMError(); + goto exit_free_sets; + } + } } } + /* cleanup whatever may exist */ if (ebtables_cmd_path) { ebtablesUnlinkTmpRootChain(&buf, 1, ifname); ebtablesUnlinkTmpRootChain(&buf, 0, ifname); @@ -3364,30 +3442,11 @@ ebiptablesApplyNewRules(virConnectPtr co ebiptablesExecCLI(&buf, &cli_status); } - if (chains_in != 0) - ebtablesCreateTmpRootChain(&buf, 1, ifname, 1); - if (chains_out != 0) - ebtablesCreateTmpRootChain(&buf, 0, ifname, 1); - - if (chains_in & (1 << VIR_NWFILTER_CHAINSUFFIX_IPv4)) - ebtablesCreateTmpSubChain(&buf, 1, ifname, L3_PROTO_IPV4_IDX, 1); - if (chains_out & (1 << VIR_NWFILTER_CHAINSUFFIX_IPv4)) - ebtablesCreateTmpSubChain(&buf, 0, ifname, L3_PROTO_IPV4_IDX, 1); - - if (chains_in & (1 << VIR_NWFILTER_CHAINSUFFIX_IPv6)) - ebtablesCreateTmpSubChain(&buf, 1, ifname, L3_PROTO_IPV6_IDX, 1); - if (chains_out & (1 << VIR_NWFILTER_CHAINSUFFIX_IPv6)) - ebtablesCreateTmpSubChain(&buf, 0, ifname, L3_PROTO_IPV6_IDX, 1); - - /* keep arp,rarp as last */ - if (chains_in & (1 << VIR_NWFILTER_CHAINSUFFIX_ARP)) - ebtablesCreateTmpSubChain(&buf, 1, ifname, L3_PROTO_ARP_IDX, 1); - if (chains_out & (1 << VIR_NWFILTER_CHAINSUFFIX_ARP)) - ebtablesCreateTmpSubChain(&buf, 0, ifname, L3_PROTO_ARP_IDX, 1); - if (chains_in & (1 << VIR_NWFILTER_CHAINSUFFIX_RARP)) - ebtablesCreateTmpSubChain(&buf, 1, ifname, L3_PROTO_RARP_IDX, 1); - if (chains_out & (1 << VIR_NWFILTER_CHAINSUFFIX_RARP)) - ebtablesCreateTmpSubChain(&buf, 0, ifname, L3_PROTO_RARP_IDX, 1); + /* create needed chains */ + if (ebtablesCreateTmpRootAndSubChains(&buf, ifname, chains_in_set , 1) || + ebtablesCreateTmpRootAndSubChains(&buf, ifname, chains_out_set, 0)) { + goto tear_down_tmpebchains; + } if (ebiptablesExecCLI(&buf, &cli_status) || cli_status != 0) goto tear_down_tmpebchains; @@ -3477,14 +3536,17 @@ ebiptablesApplyNewRules(virConnectPtr co iptablesCheckBridgeNFCallEnabled(true); } - if (chains_in != 0) + if (virHashSize(chains_in_set) != 0) ebtablesLinkTmpRootChain(&buf, 1, ifname, 1); - if (chains_out != 0) + if (virHashSize(chains_out_set) != 0) ebtablesLinkTmpRootChain(&buf, 0, ifname, 1); if (ebiptablesExecCLI(&buf, &cli_status) || cli_status != 0) goto tear_down_ebsubchains_and_unlink; + virHashFree(chains_in_set); + virHashFree(chains_out_set); + return 0; tear_down_ebsubchains_and_unlink: @@ -3519,6 +3581,10 @@ tear_down_tmpebchains: "interface %s."), ifname); +exit_free_sets: + virHashFree(chains_in_set); + virHashFree(chains_out_set); + return 1; }
Use scripts for the renaming and cleaning up of chains. This allows us to get rid of some of the code that is only capable of renaming and removing chains whose names are hardcoded. A shell function 'collect_chains' is introduced that is given the name of an ebtables chain and then recursively determines the names of all chanins that are accessed from this chain and its sub-chains using 'jumps'. The resulting list of chain names is then used to delete all the found chains by first flushing and then deleting them. The same function is also used for renaming temporary filters to their final names. I tested this with the bash and dash as script interpreters. v2: - setting IFS to intended value; works with bash and dash (phew!) Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- src/nwfilter/nwfilter_ebiptables_driver.c | 204 +++++++++++++++++------------- 1 file changed, 117 insertions(+), 87 deletions(-) Index: libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c =================================================================== --- libvirt-acl.orig/src/nwfilter/nwfilter_ebiptables_driver.c +++ libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c @@ -91,6 +91,49 @@ static char *gawk_cmd_path; #define PRINT_CHAIN(buf, prefix, ifname, suffix) \ snprintf(buf, sizeof(buf), "%c-%s-%s", prefix, ifname, suffix) +static const char ebtables_script_func_collect_chains[] = + "collect_chains()\n" + "{\n" + " local sc\n" + " sc=$(%s -t %s -L $1 | \\\n" + " sed -n \"/Bridge chain*/,$ s/.*\\-j \\([%s]-.*\\)/\\1/p\")\n" + " for tmp in `echo \"$sc\"`; do\n" + " [ -n \"$tmp\" ] && sc=\"$sc $(collect_chains $tmp)\"\n" + " done\n" + " echo \"$sc\"\n" + "}\n"; + +static const char ebiptables_script_func_rm_chains[] = + "rm_chains()\n" + "{\n" + " for tmp in `echo \"$1\"`; do [ -n \"$tmp\" ] && %s -t %s -F $tmp; done\n" + " for tmp in `echo \"$1\"`; do [ -n \"$tmp\" ] && %s -t %s -X $tmp; done\n" + "}\n"; + +static const char ebiptables_script_func_rename_chains[] = + "rename_chains()\n" + "{\n" + " for tmp in `echo \"$1\"`; do\n" + " if [ -n \"$tmp\" ]; then\n" + " tmp2=`expr substr \"$tmp\" 1 1`\n" + " if [ $tmp2 = \"%c\" ]; then\n" + " %s -t %s -E \"$tmp\" \"%c\"`expr substr \"$tmp\" 2 33`\n" + " elif [ $tmp2 = \"%c\" ]; then\n" + " %s -t %s -E \"$tmp\" \"%c\"`expr substr \"$tmp\" 2 33`\n" + " fi\n" + " fi\n" + " done\n" + "}\n"; + +static const char ebiptables_script_set_ifs[] = + "IFS=$' \\t\\n'\n" + "[ `expr length \"$IFS\"` != 3 ] && " + "IFS=$(echo | %s '{ print \"\\t\\n \"}')\n"; + +#define NWFILTER_FUNC_COLLECT_CHAINS ebtables_script_func_collect_chains +#define NWFILTER_FUNC_DELETE_CHAINS ebiptables_script_func_rm_chains +#define NWFILTER_FUNC_RENAME_CHAINS ebiptables_script_func_rename_chains +#define NWFILTER_FUNC_SET_IFS ebiptables_script_set_ifs #define VIRT_IN_CHAIN "libvirt-in" #define VIRT_OUT_CHAIN "libvirt-out" @@ -2805,95 +2848,65 @@ ebtablesCreateTmpSubChain(virBufferPtr b return 0; } - -static int -_ebtablesRemoveSubChain(virBufferPtr buf, - int incoming, - const char *ifname, - enum l3_proto_idx protoidx, - int isTempChain) +static int _ebtablesRemoveSubChains(virBufferPtr buf, + const char *ifname, + const char *chains) { - char rootchain[MAX_CHAINNAME_LENGTH], chain[MAX_CHAINNAME_LENGTH]; - char chainPrefix; - - if (isTempChain) { - chainPrefix =(incoming) ? CHAINPREFIX_HOST_IN_TEMP - : CHAINPREFIX_HOST_OUT_TEMP; - } else { - chainPrefix =(incoming) ? CHAINPREFIX_HOST_IN - : CHAINPREFIX_HOST_OUT; - } + char rootchain[MAX_CHAINNAME_LENGTH]; + unsigned i; - PRINT_ROOT_CHAIN(rootchain, chainPrefix, ifname); - PRINT_CHAIN(chain, chainPrefix, ifname, l3_protocols[protoidx].val); - - virBufferAsprintf(buf, - "%s -t %s -D %s -p 0x%x -j %s" CMD_SEPARATOR - "%s -t %s -F %s" CMD_SEPARATOR - "%s -t %s -X %s" CMD_SEPARATOR, + virBufferAsprintf(buf, NWFILTER_FUNC_COLLECT_CHAINS, + ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, chains); + virBufferAsprintf(buf, NWFILTER_FUNC_DELETE_CHAINS, ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, - rootchain, l3_protocols[protoidx].attr, chain, + ebtables_cmd_path, EBTABLES_DEFAULT_TABLE); - ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, chain, + virBufferAsprintf(buf, NWFILTER_FUNC_SET_IFS, gawk_cmd_path); + virBufferAddLit(buf, "a=\""); + for (i = 0; chains[i] != 0; i++) { + PRINT_ROOT_CHAIN(rootchain, chains[i], ifname); + virBufferAsprintf(buf, "$(collect_chains %s) ", rootchain); + } + virBufferAddLit(buf, "\"\n"); - ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, chain); + for (i = 0; chains[i] != 0; i++) { + PRINT_ROOT_CHAIN(rootchain, chains[i], ifname); + virBufferAsprintf(buf, + "%s -t %s -F %s\n", + ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, + rootchain); + } + virBufferAddLit(buf, "rm_chains \"$a\"\n"); return 0; } - -static int -ebtablesRemoveSubChain(virBufferPtr buf, - int incoming, - const char *ifname, - enum l3_proto_idx protoidx) -{ - return _ebtablesRemoveSubChain(buf, - incoming, ifname, protoidx, 0); -} - - static int ebtablesRemoveSubChains(virBufferPtr buf, const char *ifname) { - enum l3_proto_idx i; - - for (i = 0; i < L3_PROTO_LAST_IDX; i++) { - ebtablesRemoveSubChain(buf, 1, ifname, i); - ebtablesRemoveSubChain(buf, 0, ifname, i); - } + char chains[3] = { + CHAINPREFIX_HOST_IN, + CHAINPREFIX_HOST_OUT, + 0 + }; - return 0; + return _ebtablesRemoveSubChains(buf, ifname, chains); } - -static int -ebtablesRemoveTmpSubChain(virBufferPtr buf, - int incoming, - const char *ifname, - enum l3_proto_idx protoidx) -{ - return _ebtablesRemoveSubChain(buf, - incoming, ifname, protoidx, 1); -} - - static int ebtablesRemoveTmpSubChains(virBufferPtr buf, const char *ifname) { - enum l3_proto_idx i; - - for (i = 0; i < L3_PROTO_LAST_IDX; i++) { - ebtablesRemoveTmpSubChain(buf, 1, ifname, i); - ebtablesRemoveTmpSubChain(buf, 0, ifname, i); - } + char chains[3] = { + CHAINPREFIX_HOST_IN_TEMP, + CHAINPREFIX_HOST_OUT_TEMP, + 0 + }; - return 0; + return _ebtablesRemoveSubChains(buf, ifname, chains); } - static int ebtablesRenameTmpSubChain(virBufferPtr buf, int incoming, @@ -2920,31 +2933,51 @@ ebtablesRenameTmpSubChain(virBufferPtr b return 0; } - static int -ebtablesRenameTmpSubChains(virBufferPtr buf, +ebtablesRenameTmpRootChain(virBufferPtr buf, + int incoming, const char *ifname) { - enum l3_proto_idx i; + return ebtablesRenameTmpSubChain(buf, incoming, ifname, NULL); +} - for (i = 0; i < L3_PROTO_LAST_IDX; i++) { - ebtablesRenameTmpSubChain (buf, 1, ifname, l3_protocols[i].val); - ebtablesRenameTmpSubChain (buf, 0, ifname, l3_protocols[i].val); +static int +ebtablesRenameTmpSubAndRootChains(virBufferPtr buf, + const char *ifname) +{ + char rootchain[MAX_CHAINNAME_LENGTH]; + unsigned i; + char chains[3] = { + CHAINPREFIX_HOST_IN_TEMP, + CHAINPREFIX_HOST_OUT_TEMP, + 0}; + + virBufferAsprintf(buf, NWFILTER_FUNC_COLLECT_CHAINS, + ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, chains); + virBufferAsprintf(buf, NWFILTER_FUNC_RENAME_CHAINS, + CHAINPREFIX_HOST_IN_TEMP, + ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, + CHAINPREFIX_HOST_IN, + CHAINPREFIX_HOST_OUT_TEMP, + ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, + CHAINPREFIX_HOST_OUT); + + virBufferAsprintf(buf, NWFILTER_FUNC_SET_IFS, gawk_cmd_path); + virBufferAddLit(buf, "a=\""); + for (i = 0; chains[i] != 0; i++) { + PRINT_ROOT_CHAIN(rootchain, chains[i], ifname); + virBufferAsprintf(buf, "$(collect_chains %s) ", rootchain); } + virBufferAddLit(buf, "\"\n"); - return 0; -} + virBufferAddLit(buf, "rename_chains \"$a\"\n"); + ebtablesRenameTmpRootChain(buf, 1, ifname); + ebtablesRenameTmpRootChain(buf, 0, ifname); -static int -ebtablesRenameTmpRootChain(virBufferPtr buf, - int incoming, - const char *ifname) -{ - return ebtablesRenameTmpSubChain(buf, incoming, ifname, NULL); + return 0; } - static void ebiptablesInstCommand(virBufferPtr buf, const char *templ, char cmd, int pos, @@ -3654,9 +3687,7 @@ ebiptablesTearOldRules(virConnectPtr con ebtablesRemoveRootChain(&buf, 1, ifname); ebtablesRemoveRootChain(&buf, 0, ifname); - ebtablesRenameTmpSubChains(&buf, ifname); - ebtablesRenameTmpRootChain(&buf, 1, ifname); - ebtablesRenameTmpRootChain(&buf, 0, ifname); + ebtablesRenameTmpSubAndRootChains(&buf, ifname); ebiptablesExecCLI(&buf, &cli_status); } @@ -3741,12 +3772,11 @@ ebiptablesAllTeardown(const char *ifname ebtablesUnlinkRootChain(&buf, 1, ifname); ebtablesUnlinkRootChain(&buf, 0, ifname); + ebtablesRemoveSubChains(&buf, ifname); + ebtablesRemoveRootChain(&buf, 1, ifname); ebtablesRemoveRootChain(&buf, 0, ifname); - - ebtablesRemoveSubChains(&buf, ifname); } - ebiptablesExecCLI(&buf, &cli_status); return 0;
Use the name of the chain rather than its type index (enum). This pushes the later enablement of chains with user-given names into the XML parser. For now we still only allow those names that are well known ('root', 'arp', 'rarp', 'ipv4' and 'ipv6'). Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- src/conf/nwfilter_conf.c | 16 ++++++++++++---- src/conf/nwfilter_conf.h | 2 +- src/nwfilter/nwfilter_ebiptables_driver.c | 13 +++++++------ src/nwfilter/nwfilter_ebiptables_driver.h | 2 +- 4 files changed, 21 insertions(+), 12 deletions(-) Index: libvirt-acl/src/conf/nwfilter_conf.c =================================================================== --- libvirt-acl.orig/src/conf/nwfilter_conf.c +++ libvirt-acl/src/conf/nwfilter_conf.c @@ -305,6 +305,7 @@ virNWFilterDefFree(virNWFilterDefPtr def virNWFilterEntryFree(def->filterEntries[i]); VIR_FREE(def->filterEntries); + VIR_FREE(def->chainsuffix); VIR_FREE(def); } @@ -2025,21 +2026,28 @@ virNWFilterDefParseXML(xmlXPathContextPt goto cleanup; } - ret->chainsuffix = VIR_NWFILTER_CHAINSUFFIX_ROOT; chain = virXPathString("string(./@chain)", ctxt); if (chain) { - if ((ret->chainsuffix = - virNWFilterChainSuffixTypeFromString(chain)) < 0) { + if (virNWFilterChainSuffixTypeFromString(chain) < 0) { virNWFilterReportError(VIR_ERR_INTERNAL_ERROR, _("unknown chain suffix '%s'"), chain); goto cleanup; } + ret->chainsuffix = chain; /* assign an implicit priority -- support XML attribute later */ if (intMapGetByString(chain_priorities, chain, 0, &ret->chainPriority) == false) { ret->chainPriority = (NWFILTER_MAX_FILTER_PRIORITY + NWFILTER_MIN_FILTER_PRIORITY) / 2; } + chain = NULL; + } else { + ret->chainsuffix = strdup(virNWFilterChainSuffixTypeToString( + VIR_NWFILTER_CHAINSUFFIX_ROOT)); + if (ret->chainsuffix == NULL) { + virReportOOMError(); + goto cleanup; + } } uuid = virXPathString("string(./uuid)", ctxt); @@ -2905,7 +2913,7 @@ virNWFilterDefFormat(virNWFilterDefPtr d virBufferAsprintf(&buf, "<filter name='%s' chain='%s'", def->name, - virNWFilterChainSuffixTypeToString(def->chainsuffix)); + def->chainsuffix); virBufferAddLit(&buf, ">\n"); virUUIDFormat(def->uuid, uuid); Index: libvirt-acl/src/conf/nwfilter_conf.h =================================================================== --- libvirt-acl.orig/src/conf/nwfilter_conf.h +++ libvirt-acl/src/conf/nwfilter_conf.h @@ -453,7 +453,7 @@ struct _virNWFilterDef { char *name; unsigned char uuid[VIR_UUID_BUFLEN]; - int chainsuffix; /*enum virNWFilterChainSuffixType */ + char *chainsuffix; virNWFilterChainPriority chainPriority; int nentries; Index: libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c =================================================================== --- libvirt-acl.orig/src/nwfilter/nwfilter_ebiptables_driver.c +++ libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c @@ -369,7 +369,7 @@ ebiptablesRuleInstFree(ebiptablesRuleIns static int ebiptablesAddRuleInst(virNWFilterRuleInstPtr res, char *commandTemplate, - enum virNWFilterChainSuffixType neededChain, + const char *neededChain, virNWFilterChainPriority chainPriority, char chainprefix, unsigned int priority, @@ -1945,11 +1945,13 @@ ebtablesCreateRuleInstance(char chainPre goto err_exit; } - if (nwfilter->chainsuffix == VIR_NWFILTER_CHAINSUFFIX_ROOT) + if (STREQ(nwfilter->chainsuffix, + virNWFilterChainSuffixTypeToString( + VIR_NWFILTER_CHAINSUFFIX_ROOT))) PRINT_ROOT_CHAIN(chain, chainPrefix, ifname); else PRINT_CHAIN(chain, chainPrefix, ifname, - virNWFilterChainSuffixTypeToString(nwfilter->chainsuffix)); + nwfilter->chainsuffix); switch (rule->prtclType) { @@ -2516,7 +2518,7 @@ ebiptablesDisplayRuleInstance(virConnect ebiptablesRuleInstPtr inst = (ebiptablesRuleInstPtr)_inst; VIR_INFO("Command Template: '%s', Needed protocol: '%s'", inst->commandTemplate, - virNWFilterChainSuffixTypeToString(inst->neededProtocolChain)); + inst->neededProtocolChain); return 0; } @@ -3447,8 +3449,7 @@ ebiptablesApplyNewRules(virConnectPtr co for (i = 0; i < nruleInstances; i++) { sa_assert (inst); if (inst[i]->ruleType == RT_EBTABLES) { - const char *name = virNWFilterChainSuffixTypeToString( - inst[i]->neededProtocolChain); + const char *name = inst[i]->neededProtocolChain; if (inst[i]->chainprefix == CHAINPREFIX_HOST_IN_TEMP) { if (virHashUpdateEntry(chains_in_set, name, &inst[i]->chainPriority)) { Index: libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.h =================================================================== --- libvirt-acl.orig/src/nwfilter/nwfilter_ebiptables_driver.h +++ libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.h @@ -35,7 +35,7 @@ typedef struct _ebiptablesRuleInst ebipt typedef ebiptablesRuleInst *ebiptablesRuleInstPtr; struct _ebiptablesRuleInst { char *commandTemplate; - enum virNWFilterChainSuffixType neededProtocolChain; + const char *neededProtocolChain; virNWFilterChainPriority chainPriority; char chainprefix; /* I for incoming, O for outgoing */ unsigned int priority;
This patch extends the filter XML to support priorities of chains in the XML. An example would be: <filter name='allow-arpxyz' chain='arp-xyz' priority='200'> [...] </filter> The permitted values for priorities are [-1000, 1000]. By setting the pririty of a chain the order in which it is accessed from the interface root chain can be influenced. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- docs/schemas/nwfilter.rng | 7 ++++++- src/conf/nwfilter_conf.c | 42 +++++++++++++++++++++++++++++++++++++----- 2 files changed, 43 insertions(+), 6 deletions(-) Index: libvirt-acl/src/conf/nwfilter_conf.c =================================================================== --- libvirt-acl.orig/src/conf/nwfilter_conf.c +++ libvirt-acl/src/conf/nwfilter_conf.c @@ -2012,7 +2012,9 @@ virNWFilterDefParseXML(xmlXPathContextPt xmlNodePtr curr = ctxt->node; char *uuid = NULL; char *chain = NULL; + char *chain_pri_s = NULL; virNWFilterEntryPtr entry; + int chain_priority; if (VIR_ALLOC(ret) < 0) { virReportOOMError(); @@ -2026,6 +2028,26 @@ virNWFilterDefParseXML(xmlXPathContextPt goto cleanup; } + chain_pri_s = virXPathString("string(./@priority)", ctxt); + if (chain_pri_s) { + if (sscanf(chain_pri_s, "%d", &chain_priority) != 1) { + virNWFilterReportError(VIR_ERR_INTERNAL_ERROR, + _("Could not parse chain priority '%s'"), + chain_pri_s); + goto cleanup; + } + if (chain_priority < NWFILTER_MIN_FILTER_PRIORITY || + chain_priority > NWFILTER_MAX_FILTER_PRIORITY) { + virNWFilterReportError(VIR_ERR_INTERNAL_ERROR, + _("Priority '%d' is outside valid " + "range of [%d,%d]"), + chain_priority, + NWFILTER_MIN_FILTER_PRIORITY, + NWFILTER_MAX_FILTER_PRIORITY); + goto cleanup; + } + } + chain = virXPathString("string(./@chain)", ctxt); if (chain) { if (virNWFilterChainSuffixTypeFromString(chain) < 0) { @@ -2034,11 +2056,16 @@ virNWFilterDefParseXML(xmlXPathContextPt goto cleanup; } ret->chainsuffix = chain; - /* assign an implicit priority -- support XML attribute later */ - if (intMapGetByString(chain_priorities, chain, 0, - &ret->chainPriority) == false) { - ret->chainPriority = (NWFILTER_MAX_FILTER_PRIORITY + - NWFILTER_MIN_FILTER_PRIORITY) / 2; + + if (chain_pri_s) { + ret->chainPriority = chain_priority; + } else { + /* assign an implicit priority -- support XML attribute later */ + if (intMapGetByString(chain_priorities, chain, 0, + &ret->chainPriority) == false) { + ret->chainPriority = (NWFILTER_MAX_FILTER_PRIORITY + + NWFILTER_MIN_FILTER_PRIORITY) / 2; + } } chain = NULL; } else { @@ -2095,6 +2122,7 @@ virNWFilterDefParseXML(xmlXPathContextPt } VIR_FREE(chain); + VIR_FREE(chain_pri_s); return ret; @@ -2102,6 +2130,7 @@ virNWFilterDefParseXML(xmlXPathContextPt virNWFilterDefFree(ret); VIR_FREE(chain); VIR_FREE(uuid); + VIR_FREE(chain_pri_s); return NULL; } @@ -2914,6 +2943,9 @@ virNWFilterDefFormat(virNWFilterDefPtr d virBufferAsprintf(&buf, "<filter name='%s' chain='%s'", def->name, def->chainsuffix); + if (def->chainPriority != 0) + virBufferAsprintf(&buf, " priority='%d'", + def->chainPriority); virBufferAddLit(&buf, ">\n"); virUUIDFormat(def->uuid, uuid); Index: libvirt-acl/docs/schemas/nwfilter.rng =================================================================== --- libvirt-acl.orig/docs/schemas/nwfilter.rng +++ libvirt-acl/docs/schemas/nwfilter.rng @@ -293,6 +293,11 @@ </choice> </attribute> </optional> + <optional> + <attribute name="priority"> + <ref name='priority-type'/> + </attribute> + </optional> </define> <define name="filterref-node-attributes"> @@ -879,7 +884,7 @@ <define name='priority-type'> <data type="int"> - <param name="minInclusive">0</param> + <param name="minInclusive">-1000</param> <param name="maxInclusive">1000</param> </data> </define>
This patch enables chains that have a known prefix in their name. Known prefixes are: 'ipv4', 'ipv6', 'arp', 'rarp'. All prefixes are also protocols that can be evaluated on the ebtables level. Following the prefix they will be automatically connected to an interface's 'root' chain and jumped into following the protocol they evalute, i.e., a table 'arp-xyz' will be accessed from the root table using ebtables -t nat -A <iface root table> -p arp -j I-<ifname>-arp-xyz thus generating a 'root' chain like this one here: Bridge chain: libvirt-O-vnet0, entries: 5, policy: ACCEPT -p IPv4 -j O-vnet0-ipv4 -p ARP -j O-vnet0-arp -p 0x8035 -j O-vnet0-rarp -p ARP -j O-vnet0-arp-xyz -j DROP where the chain 'arp-xyz' is accessed for filtering of ARP packets. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- docs/schemas/nwfilter.rng | 16 ++++++--- src/conf/nwfilter_conf.c | 79 +++++++++++++++++++++++++++++++++++++++++++--- src/conf/nwfilter_conf.h | 3 + 3 files changed, 90 insertions(+), 8 deletions(-) Index: libvirt-acl/src/conf/nwfilter_conf.c =================================================================== --- libvirt-acl.orig/src/conf/nwfilter_conf.c +++ libvirt-acl/src/conf/nwfilter_conf.c @@ -2005,6 +2005,80 @@ err_exit: goto cleanup; } +static bool +virNWFilterIsValidChainName(const char *chainname) +{ + return chainname[strspn(chainname, VALID_CHAINNAME)] == 0; +} + +/* + * Test whether the name of the chain is supported. + * It current has to have a prefix of either one of the strings found in + * virNWFilterChainSuffixTypeToString(). + */ +static bool +virNWFilterIsAllowedChain(const char *chainname) +{ + enum virNWFilterChainSuffixType i; + const char *name, *msg; + virBuffer buf = VIR_BUFFER_INITIALIZER; + bool printed = false; + + if (!virNWFilterIsValidChainName(chainname)) { + virNWFilterReportError(VIR_ERR_INTERNAL_ERROR, + _("Chain name contains illegal characters")); + return false; + } + + if (strlen(chainname) > MAX_CHAIN_SUFFIX_SIZE) { + virNWFilterReportError(VIR_ERR_INTERNAL_ERROR, + _("name of chain is longer than %u characters"), + MAX_CHAIN_SUFFIX_SIZE); + return false; + } + + for (i = 0; i < VIR_NWFILTER_CHAINSUFFIX_LAST; i++) { + name = virNWFilterChainSuffixTypeToString(i); + if (i == VIR_NWFILTER_CHAINSUFFIX_ROOT) { + /* allow 'root' as a complete name but not as a prefix */ + if (STREQ(chainname, name)) + return true; + if (STRPREFIX(chainname, name)) + return false; + } + if (STRPREFIX(chainname, name)) + return true; + } + + virBufferAsprintf(&buf, + _("Illegal chain name '%s'. Please use a chain name " + "called '%s' or either one of the following prefixes: "), + virNWFilterChainSuffixTypeToString( + VIR_NWFILTER_CHAINSUFFIX_ROOT), + chainname); + for (i = 0; i < VIR_NWFILTER_CHAINSUFFIX_LAST; i++) { + if (i == VIR_NWFILTER_CHAINSUFFIX_ROOT) + continue; + if (printed) + virBufferAddLit(&buf, ", "); + virBufferAdd(&buf, virNWFilterChainSuffixTypeToString(i), -1); + printed = true; + } + + if (virBufferError(&buf)) { + virReportOOMError(); + virBufferFreeAndReset(&buf); + goto err_exit; + } + + msg = virBufferContentAndReset(&buf); + + virNWFilterReportError(VIR_ERR_INTERNAL_ERROR, _("%s"), msg); + VIR_FREE(msg); + +err_exit: + return false; +} static virNWFilterDefPtr virNWFilterDefParseXML(xmlXPathContextPtr ctxt) { @@ -2050,11 +2124,8 @@ virNWFilterDefParseXML(xmlXPathContextPt chain = virXPathString("string(./@chain)", ctxt); if (chain) { - if (virNWFilterChainSuffixTypeFromString(chain) < 0) { - virNWFilterReportError(VIR_ERR_INTERNAL_ERROR, - _("unknown chain suffix '%s'"), chain); + if (virNWFilterIsAllowedChain(chain) != true) goto cleanup; - } ret->chainsuffix = chain; if (chain_pri_s) { Index: libvirt-acl/src/conf/nwfilter_conf.h =================================================================== --- libvirt-acl.orig/src/conf/nwfilter_conf.h +++ libvirt-acl/src/conf/nwfilter_conf.h @@ -444,6 +444,9 @@ enum virNWFilterChainSuffixType { VIR_NWFILTER_CHAINSUFFIX_LAST, }; +# define VALID_CHAINNAME \ + "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.:-" + typedef int32_t virNWFilterChainPriority; typedef struct _virNWFilterDef virNWFilterDef; Index: libvirt-acl/docs/schemas/nwfilter.rng =================================================================== --- libvirt-acl.orig/docs/schemas/nwfilter.rng +++ libvirt-acl/docs/schemas/nwfilter.rng @@ -286,10 +286,18 @@ <attribute name="chain"> <choice> <value>root</value> - <value>arp</value> - <value>rarp</value> - <value>ipv4</value> - <value>ipv6</value> + <data type="string"> + <param name="pattern">arp[a-zA-Z0-9_\.:-]*</param> + </data> + <data type="string"> + <param name="pattern">rarp[a-zA-Z0-9_\.:-]*</param> + </data> + <data type="string"> + <param name="pattern">ipv4[a-zA-Z0-9_\.:-]*</param> + </data> + <data type="string"> + <param name="pattern">ipv6[a-zA-Z0-9_\.:-]*</param> + </data> </choice> </attribute> </optional>
So far rules' priorities have only been valid in the range [0,1000]. Now I am extending their priority into the range [-1000, 1000] for subsequently being able to sort rules and the access of (jumps into) chains following priorities. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- src/conf/nwfilter_conf.c | 7 ++++--- src/conf/nwfilter_conf.h | 6 ++++-- src/nwfilter/nwfilter_ebiptables_driver.c | 2 +- src/nwfilter/nwfilter_ebiptables_driver.h | 2 +- 4 files changed, 10 insertions(+), 7 deletions(-) Index: libvirt-acl/src/conf/nwfilter_conf.c =================================================================== --- libvirt-acl.orig/src/conf/nwfilter_conf.c +++ libvirt-acl/src/conf/nwfilter_conf.c @@ -1895,7 +1895,7 @@ virNWFilterRuleParse(xmlNodePtr node) char *statematch; int found; int found_i = 0; - unsigned int priority; + int priority; xmlNodePtr cur; virNWFilterRuleDefPtr ret; @@ -1941,8 +1941,9 @@ virNWFilterRuleParse(xmlNodePtr node) ret->priority = MAX_RULE_PRIORITY / 2; if (prio) { - if (virStrToLong_ui(prio, NULL, 10, &priority) >= 0) { - if (priority <= MAX_RULE_PRIORITY) + if (virStrToLong_i(prio, NULL, 10, &priority) >= 0) { + if (priority <= MAX_RULE_PRIORITY && + priority >= MIN_RULE_PRIORITY) ret->priority = priority; } } Index: libvirt-acl/src/conf/nwfilter_conf.h =================================================================== --- libvirt-acl.orig/src/conf/nwfilter_conf.h +++ libvirt-acl/src/conf/nwfilter_conf.h @@ -355,7 +355,7 @@ enum virNWFilterEbtablesTableType { }; -# define MIN_RULE_PRIORITY 0 +# define MIN_RULE_PRIORITY -1000 # define MAX_RULE_PRIORITY 1000 # define NWFILTER_MIN_FILTER_PRIORITY -1000 @@ -387,10 +387,12 @@ enum virNWFilterRuleFlags { void virNWFilterPrintStateMatchFlags(virBufferPtr buf, const char *prefix, int32_t flags, bool disp_none); +typedef int32_t virNWFilterRulePriority; + typedef struct _virNWFilterRuleDef virNWFilterRuleDef; typedef virNWFilterRuleDef *virNWFilterRuleDefPtr; struct _virNWFilterRuleDef { - unsigned int priority; + virNWFilterRulePriority priority; enum virNWFilterRuleFlags flags; int action; /*enum virNWFilterRuleActionType*/ int tt; /*enum virNWFilterRuleDirectionType*/ Index: libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.h =================================================================== --- libvirt-acl.orig/src/nwfilter/nwfilter_ebiptables_driver.h +++ libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.h @@ -38,7 +38,7 @@ struct _ebiptablesRuleInst { const char *neededProtocolChain; virNWFilterChainPriority chainPriority; char chainprefix; /* I for incoming, O for outgoing */ - unsigned int priority; + virNWFilterRulePriority priority; enum RuleType ruleType; }; Index: libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c =================================================================== --- libvirt-acl.orig/src/nwfilter/nwfilter_ebiptables_driver.c +++ libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c @@ -372,7 +372,7 @@ ebiptablesAddRuleInst(virNWFilterRuleIns const char *neededChain, virNWFilterChainPriority chainPriority, char chainprefix, - unsigned int priority, + virNWFilterRulePriority priority, enum RuleType ruleType) { ebiptablesRuleInstPtr inst;
The previous patch extends the priority of filtering rules into negative numbers. We now use this possibility to interleave the jumping into chains with filtering rules to for example create the 'root' table of an interface with the following sequence of rules: Bridge chain: libvirt-I-vnet0, entries: 6, policy: ACCEPT -p IPv4 -j I-vnet0-ipv4 -p ARP -j I-vnet0-arp -p ARP -j ACCEPT -p 0x8035 -j I-vnet0-rarp -p 0x835 -j ACCEPT -j DROP The '-p ARP -j ACCEPT' rule now appears between the jumps. Since the 'arp' chain has been assigned priority -700 and the 'rarp' chain -600, the above ordering can now be achieved with the following rule: <rule action='accept' direction='out' priority='-650'> <mac protocolid='arp'/> </rule> This patch now sorts the commands generating the above shown jumps into chains and interleaves their execution with those for generating rules. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- src/nwfilter/nwfilter_ebiptables_driver.c | 114 ++++++++++++++++++++++++++---- 1 file changed, 101 insertions(+), 13 deletions(-) Index: libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c =================================================================== --- libvirt-acl.orig/src/nwfilter/nwfilter_ebiptables_driver.c +++ libvirt-acl/src/nwfilter/nwfilter_ebiptables_driver.c @@ -2815,13 +2815,17 @@ ebtablesUnlinkTmpRootChain(virBufferPtr static int -ebtablesCreateTmpSubChain(virBufferPtr buf, +ebtablesCreateTmpSubChain(ebiptablesRuleInstPtr *inst, + int *nRuleInstances, int incoming, const char *ifname, enum l3_proto_idx protoidx, const char *filtername, - int stopOnError) + int stopOnError, + virNWFilterChainPriority priority) { + virBuffer buf = VIR_BUFFER_INITIALIZER; + ebiptablesRuleInstPtr tmp = *inst; char rootchain[MAX_CHAINNAME_LENGTH], chain[MAX_CHAINNAME_LENGTH]; char chainPrefix = (incoming) ? CHAINPREFIX_HOST_IN_TEMP : CHAINPREFIX_HOST_OUT_TEMP; @@ -2830,15 +2834,22 @@ ebtablesCreateTmpSubChain(virBufferPtr b PRINT_CHAIN(chain, chainPrefix, ifname, (filtername) ? filtername : l3_protocols[protoidx].val); - virBufferAsprintf(buf, + virBufferAsprintf(&buf, + CMD_DEF("%s -t %s -F %s") CMD_SEPARATOR + CMD_EXEC + CMD_DEF("%s -t %s -X %s") CMD_SEPARATOR + CMD_EXEC CMD_DEF("%s -t %s -N %s") CMD_SEPARATOR CMD_EXEC "%s" - CMD_DEF("%s -t %s -A %s -p 0x%x -j %s") CMD_SEPARATOR + CMD_DEF("%s -t %s -%%c %s %%s -p 0x%x -j %s") + CMD_SEPARATOR CMD_EXEC "%s", ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, chain, + ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, chain, + ebtables_cmd_path, EBTABLES_DEFAULT_TABLE, chain, CMD_STOPONERR(stopOnError), @@ -2847,6 +2858,24 @@ ebtablesCreateTmpSubChain(virBufferPtr b CMD_STOPONERR(stopOnError)); + if (virBufferError(&buf) || + VIR_REALLOC_N(tmp, (*nRuleInstances)+1) < 0) { + virReportOOMError(); + virBufferFreeAndReset(&buf); + return 1; + } + + *inst = tmp; + + memset(&tmp[*nRuleInstances], 0, sizeof(tmp[0])); + tmp[*nRuleInstances].priority = priority; + tmp[*nRuleInstances].commandTemplate = + virBufferContentAndReset(&buf); + tmp[*nRuleInstances].neededProtocolChain = + virNWFilterChainSuffixTypeToString(VIR_NWFILTER_CHAINSUFFIX_ROOT); + + (*nRuleInstances)++; + return 0; } @@ -3320,9 +3349,34 @@ static int ebtablesCleanAll(const char * static int ebiptablesRuleOrderSort(const void *a, const void *b) { + const ebiptablesRuleInstPtr insta = (const ebiptablesRuleInstPtr)a; + const ebiptablesRuleInstPtr instb = (const ebiptablesRuleInstPtr)b; + const char *root = virNWFilterChainSuffixTypeToString( + VIR_NWFILTER_CHAINSUFFIX_ROOT); + bool root_a = STREQ(insta->neededProtocolChain, root); + bool root_b = STREQ(instb->neededProtocolChain, root); + + /* ensure root chain commands appear before all others since + we will need them to create the child chains */ + if (root_a) { + if (root_b) { + goto normal; + } + return -1; /* a before b */ + } + if (root_b) { + return 1; /* b before a */ + } +normal: + return (insta->priority - instb->priority); +} + +static int +ebiptablesRuleOrderSortPtr(const void *a, const void *b) +{ const ebiptablesRuleInstPtr *insta = a; const ebiptablesRuleInstPtr *instb = b; - return ((*insta)->priority - (*instb)->priority); + return ebiptablesRuleOrderSort(*insta, *instb); } static int @@ -3392,9 +3446,12 @@ ebtablesGetProtoIdxByFiltername(const ch static int ebtablesCreateTmpRootAndSubChains(virBufferPtr buf, const char *ifname, - virHashTablePtr chains, int direction) + virHashTablePtr chains, int direction, + ebiptablesRuleInstPtr *inst, + int *nRuleInstances) { int rc = 0, i; + virNWFilterChainPriority *priority; if (virHashSize(chains) != 0) { char **filter_names; @@ -3412,13 +3469,19 @@ ebtablesCreateTmpRootAndSubChains(virBuf filter_names[i]); if ((int)idx < 0) continue; - ebtablesCreateTmpSubChain(buf, direction, ifname, idx, - filter_names[i], 1); + priority = virHashLookup(chains, filter_names[i]); + if (ebtablesCreateTmpSubChain(inst, nRuleInstances, + direction, ifname, idx, + filter_names[i], 1, + *priority)) { + goto exit_free_keys; + } } +exit_free_keys: virHashFreeKeys(chains, (void **)filter_names); } - err_exit: +err_exit: return rc; } @@ -3428,7 +3491,7 @@ ebiptablesApplyNewRules(virConnectPtr co int nruleInstances, void **_inst) { - int i; + int i, j; int cli_status; ebiptablesRuleInstPtr *inst = (ebiptablesRuleInstPtr *)_inst; virBuffer buf = VIR_BUFFER_INITIALIZER; @@ -3436,6 +3499,8 @@ ebiptablesApplyNewRules(virConnectPtr co chains_out_set = virHashCreate(10, NULL); bool haveIptables = false; bool haveIp6tables = false; + ebiptablesRuleInstPtr ebtChains = NULL; + int nEbtChains = 0; if (!chains_in_set || !chains_out_set) { virReportOOMError(); @@ -3443,7 +3508,8 @@ ebiptablesApplyNewRules(virConnectPtr co } if (nruleInstances > 1 && inst) - qsort(inst, nruleInstances, sizeof(inst[0]), ebiptablesRuleOrderSort); + qsort(inst, nruleInstances, sizeof(inst[0]), + ebiptablesRuleOrderSortPtr); /* scan the rules to see which chains need to be created */ for (i = 0; i < nruleInstances; i++) { @@ -3477,18 +3543,33 @@ ebiptablesApplyNewRules(virConnectPtr co } /* create needed chains */ - if (ebtablesCreateTmpRootAndSubChains(&buf, ifname, chains_in_set , 1) || - ebtablesCreateTmpRootAndSubChains(&buf, ifname, chains_out_set, 0)) { + if (ebtablesCreateTmpRootAndSubChains(&buf, ifname, chains_in_set , 1, + &ebtChains, &nEbtChains) || + ebtablesCreateTmpRootAndSubChains(&buf, ifname, chains_out_set, 0, + &ebtChains, &nEbtChains)) { goto tear_down_tmpebchains; } + if (nEbtChains > 0) + qsort(&ebtChains[0], nEbtChains, sizeof(ebtChains[0]), + ebiptablesRuleOrderSort); + if (ebiptablesExecCLI(&buf, &cli_status) || cli_status != 0) goto tear_down_tmpebchains; + /* process ebtables commands; interleave commands from filters with + commands for creating and connecting ebtables chains */ + j = 0; for (i = 0; i < nruleInstances; i++) { sa_assert (inst); switch (inst[i]->ruleType) { case RT_EBTABLES: + while (j < nEbtChains && + ebtChains[j].priority <= inst[i]->priority) { + ebiptablesInstCommand(&buf, + ebtChains[j++].commandTemplate, + 'A', -1, 1); + } ebiptablesInstCommand(&buf, inst[i]->commandTemplate, 'A', -1, 1); @@ -3502,6 +3583,11 @@ ebiptablesApplyNewRules(virConnectPtr co } } + while (j < nEbtChains) + ebiptablesInstCommand(&buf, + ebtChains[j++].commandTemplate, + 'A', -1, 1); + if (ebiptablesExecCLI(&buf, &cli_status) || cli_status != 0) goto tear_down_tmpebchains; @@ -3580,6 +3666,7 @@ ebiptablesApplyNewRules(virConnectPtr co virHashFree(chains_in_set); virHashFree(chains_out_set); + VIR_FREE(ebtChains); return 0; @@ -3618,6 +3705,7 @@ tear_down_tmpebchains: exit_free_sets: virHashFree(chains_in_set); virHashFree(chains_out_set); + VIR_FREE(ebtChains); return 1; }
Add test case for the chain names with known prefixes and the chain priority. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- tests/nwfilterxml2xmlin/chain_prefixtest1.xml | 37 +++++++++++++++++++++++++ tests/nwfilterxml2xmlout/chain_prefixtest1.xml | 21 ++++++++++++++ tests/nwfilterxml2xmltest.c | 2 + 3 files changed, 60 insertions(+) Index: libvirt-acl/tests/nwfilterxml2xmlin/chain_prefixtest1.xml =================================================================== --- /dev/null +++ libvirt-acl/tests/nwfilterxml2xmlin/chain_prefixtest1.xml @@ -0,0 +1,37 @@ +<filter name='testcase' chain='arp-testme' priority='-650'> + <uuid>e5700920-a333-4c05-8016-b669e46b7599</uuid> + <rule action='accept' direction='out'> + <arp srcmacaddr='1:2:3:4:5:6' srcmacmask='ff:ff:ff:ff:ff:ff' + protocolid='arp' + dstmacaddr='aa:bb:cc:dd:ee:ff' dstmacmask='ff:ff:ff:ff:ff:ff' + hwtype='12' + protocoltype='34' + opcode='Request' + arpsrcmacaddr='1:2:3:4:5:6' + arpdstmacaddr='a:b:c:d:e:f'/> + </rule> + + <rule action='accept' direction='out'> + <arp srcmacaddr='1:2:3:4:5:6' srcmacmask='ff:ff:ff:ff:ff:ff' + opcode='1' hwtype='255' protocoltype='255'/> + </rule> + + <rule action='accept' direction='out'> + <arp srcmacaddr='1:2:3:4:5:6' srcmacmask='ff:ff:ff:ff:ff:ff' + opcode='11' hwtype='256' protocoltype='256'/> + </rule> + + <rule action='accept' direction='out'> + <arp srcmacaddr='1:2:3:4:5:6' srcmacmask='ff:ff:ff:ff:ff:ff' + opcode='65535' hwtype='65535' protocoltype='65535' /> + </rule> + + <rule action='accept' direction='out'> + <arp srcmacaddr='1:2:3:4:5:6' srcmacmask='ff:ff:ff:ff:ff:ff' + opcode='65536' hwtype='65536' protocoltype='65536' /> + </rule> + + <rule action='accept' direction='in'> + <arp gratuitous='true'/> + </rule> +</filter> Index: libvirt-acl/tests/nwfilterxml2xmlout/chain_prefixtest1.xml =================================================================== --- /dev/null +++ libvirt-acl/tests/nwfilterxml2xmlout/chain_prefixtest1.xml @@ -0,0 +1,21 @@ +<filter name='testcase' chain='arp-testme' priority='-650'> + <uuid>e5700920-a333-4c05-8016-b669e46b7599</uuid> + <rule action='accept' direction='out' priority='500'> + <arp srcmacaddr='01:02:03:04:05:06' srcmacmask='ff:ff:ff:ff:ff:ff' dstmacaddr='aa:bb:cc:dd:ee:ff' dstmacmask='ff:ff:ff:ff:ff:ff' hwtype='12' protocoltype='34' opcode='Request' arpsrcmacaddr='01:02:03:04:05:06' arpdstmacaddr='0a:0b:0c:0d:0e:0f'/> + </rule> + <rule action='accept' direction='out' priority='500'> + <arp srcmacaddr='01:02:03:04:05:06' srcmacmask='ff:ff:ff:ff:ff:ff' hwtype='255' protocoltype='255' opcode='Request'/> + </rule> + <rule action='accept' direction='out' priority='500'> + <arp srcmacaddr='01:02:03:04:05:06' srcmacmask='ff:ff:ff:ff:ff:ff' hwtype='256' protocoltype='256' opcode='11'/> + </rule> + <rule action='accept' direction='out' priority='500'> + <arp srcmacaddr='01:02:03:04:05:06' srcmacmask='ff:ff:ff:ff:ff:ff' hwtype='65535' protocoltype='65535' opcode='65535'/> + </rule> + <rule action='accept' direction='out' priority='500'> + <arp srcmacaddr='01:02:03:04:05:06' srcmacmask='ff:ff:ff:ff:ff:ff'/> + </rule> + <rule action='accept' direction='in' priority='500'> + <arp gratuitous='true'/> + </rule> +</filter> Index: libvirt-acl/tests/nwfilterxml2xmltest.c =================================================================== --- libvirt-acl.orig/tests/nwfilterxml2xmltest.c +++ libvirt-acl/tests/nwfilterxml2xmltest.c @@ -148,6 +148,8 @@ mymain(void) DO_TEST("example-1", false); DO_TEST("example-2", false); + DO_TEST("chain_prefixtest1", true); /* derived from arp-test */ + return (ret==0 ? EXIT_SUCCESS : EXIT_FAILURE); }
Stefan, Can't you achieve the same thing by reserving an early block of priorities (and a late one, for system stuff that should be done late)? The problem is that at the moment rules (in the 'root' table) can have
On 10/19/2011 03:02 PM, David Stevens wrote: priorities [0, 1000]. So nothing prevents one to write a rule with priority 0. However, due to how nwfilters works right now the jumps into the protocol-specific tables will always be created *before* those rules. I am trying to address this now with assigning negative numbers to the chains to achieve the same sorting and maintain backwards compatibility.
If you use negative numbers, then you lose the capability of ever extending priorities to interpret the negative number as "from the end" as done in ebtables/iptables line numbers. I think that is more useful, and having to do that outside of priorities would mean extra parsing and encoding to get that effect.
There is no relation between priorities and the ordering parameter to the ebtables / iptables commands. The priorities were introduced so that more complex filters can be built by composing them of individual filters and yet have their filtering rules be created in the 'proper' order that goes beyond of how they are reference through filter references inside the filters and their appearance in the XML. I don't see how this could be changed, but I'd be curious to see 'how'.
I also think that nwfilters ought to reflect the underlying filter mechanisms as much as possible. Really, I'd prefer they were simply parameterized shell scripts of ebtables/iptables commands run at significant events (start-up, shutdown, migrate) instead of XML-encoded things. Then the full feature sets of ebtables/iptables would be available "for free", instead of requiring libvirt patches to, e.g., add "return/continue" or multiple chains.
If you want to design another filtering subsytem for libvirt, please go ahead. mwfilters currently works with XML and I don't see we can change that so easily.
Barring that, at least I think what nwfilters provides should be a close map to ebtables/iptables capabilities. Mapping line numbers into a wide range
It was not intended to be a 1:1 mapping but allow portability to other system. Of course, the lack of similar functionality on other system may be quite a bit of work to overcome first.
of priorities is straightforward, but if you use negative numbers in an ordinary sort, you can no longer use the sign as ebtables/iptables does. Because you've limited the range, you could do something hacky with offsets (anything below "-1000" is "from the end" or some such), but that's arcane. Right, 'arcane'... Using priorities in multiple places is very like programming in basic and what both ebtables/iptables and nwfilters could use better I think would be the capability to label rules by name and reference the label to identify the rule location. Then you might, e.g., add a rule at "myrules + 5" and don't care what particular priority/line number "myrules" is. You have patches for that?
+-DLS
On 10/19/2011 04:55 PM, David Stevens wrote:
-----Stefan Berger <stefanb@linux.vnet.ibm.com> wrote: -----
The problem is that at the moment rules (in the 'root' table) can have priorities [0, 1000]. So nothing prevents one to write a rule with priority 0. However, due to how nwfilters works right now the jumps into the protocol-specific tables will always be created *before* those rules. I am trying to address this now with assigning negative numbers to the chains to achieve the same sorting and maintain backwards compatibility.
Priorities aren't directly line numbers, but I think extending negative numbers to be "from the end" as ebtables/iptables would be a useful thing (and less arcane due to the precedent already there). But since you are extending to allow more chains, couldn't you in fact just expose the root chain to XML and create a default that
does the protocol switch that's generated in code now? Then, you The protocol 'switch', assuming we both talk about 'the same', becomes a lot more flexible and dynamic with this patch series. It lets you insert jumps to new chains (whose names have known protocol names as prefixes) and interleave them with rules in the 'root' table. could insert new chains before the standard ones, reorder, or do anything you want -- with "RETURN" as the policy or action for acceptable frames in the early chains so later chains are still run. I do have the intention to accept your 'RETURN' and 'CONTINUE' patch. So
It's already exposed.. you can add the following rule to the 'clean-traffic' filter <rule action='drop' direction='inout' priority='999'> <arp/> </rule> and it will appear in the interface root chain. that's not going to be the problem. I just have some concerns about how the multiple IP address support is implemented. I don't think it works with multiples of anything else than what is in the IP variable, i.e., comma-separated 'items' in other variables.
If you didn't want to expose libvirt-{I,O}-vnetXX chains, couldn't you at least accomplish the same thing with new chains in the code-generated chains by adding a "pre-protocol" chain assuming "RETURN" is available. Then, a filter that adds to "pre-protocol" (or whatever you call it) would always happen before the standard chains. A similar chain hook could be done for post-protocol chains, if those were converted to do "RETURN" instead of ACCEPT/DROP too.
Using priorities in multiple places is very like programming in basic
and what both ebtables/iptables and nwfilters could use better I think would
be the capability to label rules by name and reference d label to identify the
rule location. Then you might, e.g., add a rule at "myrules + 5" and don't care
what particular priority/line number "myrules" is.
You have patches for that?
Actually, you do. If the labels are new chains then the existing priority within that chain is essentially the same. But the existing priority mechanism doesn't have the full flexibility available in ebtables/iptables with "insert before", "append", "offset from beginning", "offset from end". Wouldn't you get that with the combination of user-defined chains, a user-modifiable root chain, and priorities interpretted like this:
Priorities are used for sorting and not for absolute position of a rule within a chain. You can compose filters of building blocks and leave some building blocks out and you'll end up missing rules with certain priorities. So the mapping to positions from priorities directly is not possible in that way. Stefan
0 - insert at beginning N - insert at N MAX - append at end (and this ought to be 2G-1, not 1000) -N - insert at END-N. ?
+-DLS
2011/10/19 David Stevens <dlstevens@us.ibm.com>:
I also think that nwfilters ought to reflect the underlying filter mechanisms as much as possible. Really, I'd prefer they were simply parameterized shell scripts of ebtables/iptables commands run at significant events (start-up, shutdown, migrate) instead of XML-encoded things. Then the full feature sets of ebtables/iptables would be available "for free", instead of requiring libvirt patches to, e.g., add "return/continue" or multiple chains.
Well, you miss the point that nwfilters is meant as a general firewall interface. ebtables/iptables just happens to be an implementation of this interface. Using ebtables/iptables specific shell scripts would replace the generic interface with something specific to ebtables/iptables. The general nwfilters interface allows to have an ebtables/iptables based implementation for the Linux based hypervisors and an ipfw based implementation for FreeBSD and other implementations that are specific to VirtualBox, ESX, Hyper-V, PowerHypervisor etc. How well the nwfilters interface maps to all those different firewalls is another question, but with this general interface there is at least the possibility to configure the different firewalls of different hypervisors via libvirt. -- Matthias Bolte http://photron.blogspot.com
2011/10/19 David Stevens <dlstevens@us.ibm.com>:
-----Matthias Bolte <matthias.bolte@googlemail.com> wrote: -----
Well, you miss the point that nwfilters is meant as a general firewall interface. ebtables/iptables just happens to be an implementation of this interface. Using ebtables/iptables specific shell scripts would replace the generic interface with something specific to ebtables/iptables.
No, I just don't agree with it. I think an administrator on OS "X" is already familiar with the firewall capabilities on his/her OS and so having a new, less-capable abstraction instead of the firewall s/he already knows is not a benefit. If these were instead hooks in libvirt that called sample scripts per-OS, administrators could easily do whatever they want to do when an interface is brought up, brought down, or migrated. They could then also make full use of their firewall capabilities and customize completely as needed.
The goal of libvirt is to give you an interface that is not specific to the underlying hypervisor, firewall, storage etc. In case of your suggestion about firewall specific scripts that are triggered by libvirt on specific events, this is already possible. Libvirt provides you with such hooks: http://libvirt.org/hooks.html -- Matthias Bolte http://photron.blogspot.com
Hi David,
<font face="Default Sans Serif,Verdana,Arial,Helvetica,sans-serif" size="2"><div><br></div><font color="#990099">-----Matthias Bolte <a class="moz-txt-link-rfc2396E" href="mailto:matthias.bolte@googlemail.com"><matthias.bolte@googlemail.com></a> wrote: -----<br></font><br>><br>>Well, you miss the point that nwfilters is meant as a general<br>>firewall<br>>interface. ebtables/iptables just happens to be an implementation of<br>>this interface. Using ebtables/iptables specific shell scripts would<br>>replace the generic interface with something specific to<br>>ebtables/iptables.<br><br> ...
Could you please configure your mail client to stop sending this HTML garbage or at least make it send plain text together with HTML? Thanks, Jirka
On Wed, Oct 19, 2011 at 03:14:20PM -0600, David Stevens wrote:
-----Matthias Bolte [1]<matthias.bolte@googlemail.com> wrote: -----
Well, you miss the point that nwfilters is meant as a general firewall interface. ebtables/iptables just happens to be an implementation of this interface. Using ebtables/iptables specific shell scripts would replace the generic interface with something specific to ebtables/iptables.
No, I just don't agree with it. I think an administrator on OS "X" is already familiar with the firewall capabilities on his/her OS and so having a new, less-capable abstraction instead of the firewall s/he already knows is not a benefit. If these were instead hooks in libvirt that called sample scripts per-OS, administrators could easily do whatever they want to do when an interface is brought up, brought down, or migrated. They could then also make full use of their firewall capabilities and customize completely as needed.
Whether you agree with it or not is irrelevant for libvirt patch review discussions. The abstraction into a implementation independant syntax & API is the primary reason for libvirt's existance, and is not up for debate. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
participants (5)
-
Daniel P. Berrange -
David Stevens -
Jiri Denemark -
Matthias Bolte -
Stefan Berger