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Make filter creation in root table more flexible

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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>
This commit is contained in:
Stefan Berger 2011-11-18 11:58:17 -05:00 committed by Stefan Berger
parent 4df34ec394
commit be39b3e4a5
1 changed files with 102 additions and 32 deletions
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134
src/nwfilter/nwfilter_ebiptables_driver.c
View File

@ -140,6 +140,11 @@ enum l3_proto_idx {
#define USHORTMAP_ENTRY_IDX(IDX, ATT, VAL) [IDX] = { .attr = ATT, .val = VAL }
/* A lookup table for translating ethernet protocol IDs to human readable
* strings. None of the human readable strings must be found as a prefix
* in another entry here (example 'ab' would be found in 'abc') to allow
* for prefix matching.
*/
static const struct ushort_map l3_protocols[] = {
USHORTMAP_ENTRY_IDX(L3_PROTO_IPV4_IDX, ETHERTYPE_IP , "ipv4"),
USHORTMAP_ENTRY_IDX(L3_PROTO_IPV6_IDX, ETHERTYPE_IPV6 , "ipv6"),
@ -2662,6 +2667,7 @@ ebtablesCreateTmpSubChain(virBufferPtr buf,
int incoming,
const char *ifname,
enum l3_proto_idx protoidx,
const char *filtername,
int stopOnError)
{
char rootchain[MAX_CHAINNAME_LENGTH], chain[MAX_CHAINNAME_LENGTH];
@ -2669,7 +2675,8 @@ ebtablesCreateTmpSubChain(virBufferPtr buf,
: 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
@ -3176,6 +3183,14 @@ ebiptablesRuleOrderSort(const void *a, const void *b)
return ((*insta)->priority - (*instb)->priority);
}
static int
ebiptablesFilterOrderSort(const virHashKeyValuePairPtr a,
const virHashKeyValuePairPtr b)
{
/* elements' values has been limited to range [-1000, 1000] */
return *(virNWFilterChainPriority *)a->value -
*(virNWFilterChainPriority *)b->value;
}
static void
iptablesCheckBridgeNFCallEnabled(bool isIPv6)
@ -3215,6 +3230,54 @@ iptablesCheckBridgeNFCallEnabled(bool isIPv6)
}
}
/*
* 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;
virHashKeyValuePairPtr filter_names;
if (ebtablesCreateTmpRootChain(buf, direction, ifname, 1) < 0)
return -1;
filter_names = virHashGetItems(chains,
ebiptablesFilterOrderSort);
if (filter_names == NULL)
return -1;
for (i = 0; filter_names[i].key; i++) {
enum l3_proto_idx idx = ebtablesGetProtoIdxByFiltername(
filter_names[i].key);
if ((int)idx < 0)
continue;
rc = ebtablesCreateTmpSubChain(buf, direction, ifname, idx,
filter_names[i].key, 1);
if (rc < 0)
break;
}
VIR_FREE(filter_names);
return rc;
}
static int
ebiptablesApplyNewRules(virConnectPtr conn ATTRIBUTE_UNUSED,
@ -3225,24 +3288,43 @@ ebiptablesApplyNewRules(virConnectPtr conn ATTRIBUTE_UNUSED,
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);
virHashTablePtr 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);
@ -3252,30 +3334,11 @@ ebiptablesApplyNewRules(virConnectPtr conn ATTRIBUTE_UNUSED,
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;
@ -3365,14 +3428,17 @@ ebiptablesApplyNewRules(virConnectPtr conn ATTRIBUTE_UNUSED,
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:
@ -3407,6 +3473,10 @@ tear_down_tmpebchains:
"interface %s."),
ifname);
exit_free_sets:
virHashFree(chains_in_set);
virHashFree(chains_out_set);
return 1;
}