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Re: [libvirt] [PATCHv5 3/5] domifaddr: Implement the API for qemu



On Tue, Sep 3, 2013 at 7:46 PM, Osier Yang <jyang redhat com> wrote:
>
> Except what Daniel pointed out:
>
>
> On 01/09/13 21:43, Nehal J Wani wrote:
>
> By querying the qemu guest agent with the QMP command
> "guest-network-get-interfaces" and converting the received JSON
> output to structured objects.
>
> Although "ifconfig" is deprecated, IP aliases created by "ifconfig"
> are supported by this API. The legacy syntax of an IP alias is:
> "<ifname>:<alias-name>". Since we want all aliases to be clubbed
> under parent interface, simply stripping ":<alias-name>" suffices.
>
>
> s/suffices/suffixes/,

Here, I by suffices, I meant: "Be enough or adequate."


>
>
> Note that IP aliases formed by "ip" aren't visible to "ifconfig",
> and aliases created by "ip" do not have any specific name. But
> we are lucky, as qemuga detects aliases created by both.
>
>
> s/qemuga/qemu guest agent/, or s/qemuga/qemu-ga/,
>
>
>
> src/qemu/qemu_agent.h:
>   * Define qemuAgentGetInterfaces
>
> src/qemu/qemu_agent.c:
>   * Implement qemuAgentGetInterface
>
> src/qemu/qemu_driver.c:
>   * New function qemuDomainInterfaceAddresses
>
> src/remote_protocol-sructs:
>   * Define new structs
>
> tests/qemuagenttest.c:
>   * Add new test: testQemuAgentGetInterfaces
>     Test cases for IP aliases, 0 or multiple ipv4/ipv6 address(es)
>
> ---
>  src/qemu/qemu_agent.c  | 193
> +++++++++++++++++++++++++++++++++++++++++++++++++
>  src/qemu/qemu_agent.h  |   3 +
>  src/qemu/qemu_driver.c |  55 ++++++++++++++
>  tests/qemuagenttest.c  | 149 ++++++++++++++++++++++++++++++++++++++
>  4 files changed, 400 insertions(+)
>
> diff --git a/src/qemu/qemu_agent.c b/src/qemu/qemu_agent.c
> index 2cd0ccc..009ed77 100644
> --- a/src/qemu/qemu_agent.c
> +++ b/src/qemu/qemu_agent.c
> @@ -1320,6 +1320,199 @@ cleanup:
>  }
>
>  /*
> + * qemuAgentGetInterfaces:
> + * @mon: Agent
>
>
> s/Agent/Agent monitor/,
>
>
> + * @ifaces: pointer to an array of pointers pointing to interface objects
> + *
> + * Issue guest-network-get-interfaces to guest agent, which returns the
>
>
> s/the/a/,
>
>
> + * list of a interfaces of a running domain along with their IP and MAC
>
>
> s/of a/of/,
>
>
> + * addresses.
> + *
> + * Returns: number of interfaces on success, -1 on error.
> + */
> +int
> +qemuAgentGetInterfaces(qemuAgentPtr mon,
> +                       virDomainInterfacePtr **ifaces)
> +{
> +    int ret = -1;
> +    size_t i, j;
> +    int size = -1;
> +    virJSONValuePtr cmd = NULL;
> +    virJSONValuePtr reply = NULL;
> +    virJSONValuePtr ret_array = NULL;
> +    size_t ifaces_count = 0;
> +    size_t addrs_count = 0;
> +    virDomainInterfacePtr *ifaces_ret = NULL;
> +    virHashTablePtr ifaces_store = NULL;
> +
> +    /* Initially the bag of ifaces is empty */
>
>
> "bag" is magic here, how about:
>
> /* Hash table to handle the interface alias */
>
>
> +    if (!(ifaces_store = virHashCreate(ifaces_count, NULL)))
> +        return -1;
> +
> +    if (!(cmd = qemuAgentMakeCommand("guest-network-get-interfaces",
> NULL)))
> +       return -1;
>
>
> You should free the created hash table.

In the label cleanup, I have freed the has table.


>
>
> +
> +    if (qemuAgentCommand(mon, cmd, &reply,
> VIR_DOMAIN_QEMU_AGENT_COMMAND_BLOCK) < 0 ||
> +        qemuAgentCheckError(cmd, reply) < 0) {
> +        goto cleanup;
> +    }
> +
> +    if (!(ret_array = virJSONValueObjectGet(reply, "return"))) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("qemu agent didn't provide 'return' field"));
> +        goto cleanup;
> +    }
> +
> +    if ((size = virJSONValueArraySize(ret_array)) < 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("qemu agent didn't return an array of
> interfaces"));
> +        goto cleanup;
> +    }
> +
> +    for (i = 0; i < size; i++) {
> +        virJSONValuePtr tmp_iface = virJSONValueArrayGet(ret_array, i);
> +        virJSONValuePtr ip_addr_arr = NULL;
> +        const char *hwaddr, *ifname_s, *name = NULL;
> +        char **ifname = NULL;
> +        int ip_addr_arr_size;
> +        virDomainInterfacePtr iface = NULL;
> +
> +        /* Shouldn't happen but doesn't hurt to check neither */
> +        if (!tmp_iface) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                           _("something has went really wrong"));
> +            goto error;
> +        }
> +
> +        /* interface name is required to be presented */
> +        name = virJSONValueObjectGetString(tmp_iface, "name");
> +        if (!name) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                           _("qemu agent didn't provide 'name' field"));
> +            goto error;
> +        }
> +
> +        /* Handle aliases of type <ifname>:<alias-name> */
>
>
> I think no need to mention the "type" here, since it only can be
> "ifname:alias". So how about:
>
> /* Handle interface alias (<ifname>:<alias>
>
>
> +        ifname = virStringSplit(name, ":", 2);
> +        ifname_s = ifname[0];
> +
> +        iface = virHashLookup(ifaces_store, ifname_s);
> +
> +        /* If the storage bag doesn't contain this iface, add it */
>
>
> s/storage bag/hash table/,
>
>
> +        if (!iface) {
> +            if (VIR_EXPAND_N(ifaces_ret, ifaces_count, 1) < 0)
> +                goto cleanup;
>
>
> goto error;
>
> +
> +            if (VIR_ALLOC(ifaces_ret[ifaces_count - 1]) < 0)
> +                goto cleanup;
>
>
> goto error;
>
> +
> +            if (virHashAddEntry(ifaces_store, ifname_s,
> +                                ifaces_ret[ifaces_count - 1]) < 0)
>
>
> Do we really need to use the virDomainInterfacePtr object as hash value?
> isn't
> a reference count is enough? if you use the reference count as the hash
> value,
> the logic can be more compact and clear:
>
>      if (!iface) {
>          VIR_EXPAND_N
>          VIR_ALLOC
>          virHashAddEntry
>          .....
>      }
>
>      iface = iface_ret[ifaces_count - 1];
>

If I am not wrong, are you suggesting to have the position of the nth interface
in ifaces_ret as the reference count?

> +                goto cleanup;
>
>
> goto error;
>
>
> +
> +            iface = ifaces_ret[ifaces_count - 1];
> +            iface->naddrs = 0;
> +
> +            if (VIR_STRDUP(iface->name, ifname_s) < 0)
> +                goto error;
> +
> +            /* hwaddr might be omitted */
> +            hwaddr = virJSONValueObjectGetString(tmp_iface,
> "hardware-address");
> +            if (hwaddr && VIR_STRDUP(iface->hwaddr, hwaddr) < 0)
> +                goto error;
> +        }
> +
> +        /* Has to be freed for each interface. */
> +        virStringFreeList(ifname);
> +
> +        /* as well as IP address which - moreover -
> +         * can be presented multiple times */
> +        ip_addr_arr = virJSONValueObjectGet(tmp_iface, "ip-addresses");
> +        if (!ip_addr_arr)
> +            continue;
> +
> +        if ((ip_addr_arr_size = virJSONValueArraySize(ip_addr_arr)) < 0)
> +            /* Mmm, empty 'ip-address'? */
> +            continue;
> +
> +        /* If current iface already exists, continue with the count */
> +        addrs_count = iface->naddrs;
> +
> +        for (j = 0; j < ip_addr_arr_size; j++) {
> +
>
>
> Meaningless blank line.
>
>
> +            if (VIR_EXPAND_N(iface->addrs, addrs_count, 1)  < 0)
> +                goto error;
> +
> +            virJSONValuePtr ip_addr_obj = virJSONValueArrayGet(ip_addr_arr,
> j);
> +            virDomainIPAddressPtr ip_addr = &iface->addrs[addrs_count - 1];
> +            const char *type, *addr;
> +
> +            /* Shouldn't happen but doesn't hurt to check neither */
> +            if (!ip_addr_obj) {
> +                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                               _("something has went really wrong"));
> +                goto error;
> +            }
> +
> +            type = virJSONValueObjectGetString(ip_addr_obj,
> "ip-address-type");
> +            if (!type) {
> +                virReportError(VIR_ERR_INTERNAL_ERROR,
> +                               _("qemu agent didn't provide
> 'ip-address-type'"
> +                                 " field for interface '%s'"), name);
> +                goto error;
> +            } else if (STREQ(type, "ipv4")) {
> +                ip_addr->type = VIR_IP_ADDR_TYPE_IPV4;
> +            } else if (STREQ(type, "ipv6")) {
> +                ip_addr->type = VIR_IP_ADDR_TYPE_IPV6;
> +            } else {
> +                virReportError(VIR_ERR_INTERNAL_ERROR,
> +                               _("unknown ip address type '%s'"),
> +                               type);
> +                goto error;
> +            }
> +
> +            addr = virJSONValueObjectGetString(ip_addr_obj, "ip-address");
> +            if (!addr) {
> +                virReportError(VIR_ERR_INTERNAL_ERROR,
> +                               _("qemu agent didn't provide 'ip-address'"
> +                                 " field for interface '%s'"), name);
> +                goto error;
> +            }
> +            if (VIR_STRDUP(ip_addr->addr, addr) < 0)
> +                goto error;
> +
> +            if (virJSONValueObjectGetNumberUint(ip_addr_obj, "prefix",
> +                                                &ip_addr->prefix) < 0) {
> +                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                               _("malformed 'prefix' field"));
> +                goto error;
> +            }
> +        }
> +
> +        iface->naddrs = addrs_count;
> +    }
> +
> +    *ifaces = ifaces_ret;
> +    ifaces_ret = NULL;
> +    ret = ifaces_count;
> +
> +cleanup:
> +    virJSONValueFree(cmd);
> +    virJSONValueFree(reply);
> +    virHashFree(ifaces_store);
> +    return ret;
> +
> +error:
> +    if (ifaces_ret) {
> +        for (i = 0; i < ifaces_count; i++)
> +            virDomainInterfaceFree(ifaces_ret[i]);
> +    }
> +    VIR_FREE(ifaces_ret);
> +
> +    goto cleanup;
> +}
> +
> +/*
>   * qemuAgentFSThaw:
>   * @mon: Agent
>   *
> diff --git a/src/qemu/qemu_agent.h b/src/qemu/qemu_agent.h
> index 5fbacdb..58b56fd 100644
> --- a/src/qemu/qemu_agent.h
> +++ b/src/qemu/qemu_agent.h
> @@ -76,6 +76,9 @@ int qemuAgentFSThaw(qemuAgentPtr mon);
>  int qemuAgentSuspend(qemuAgentPtr mon,
>                       unsigned int target);
>
> +int qemuAgentGetInterfaces(qemuAgentPtr mon,
> +                           virDomainInterfacePtr **ifaces);
> +
>  int qemuAgentArbitraryCommand(qemuAgentPtr mon,
>                                const char *cmd,
>                                char **result,
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index ed29373..908f19c 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -15870,6 +15870,60 @@ qemuNodeSuspendForDuration(virConnectPtr conn,
>      return nodeSuspendForDuration(target, duration, flags);
>  }
>
> +static int
> +qemuDomainInterfaceAddresses(virDomainPtr dom,
> +                             virDomainInterfacePtr **ifaces,
> +                             unsigned int flags)
> +{
> +    virQEMUDriverPtr driver = dom->conn->privateData;
> +    qemuDomainObjPrivatePtr priv = NULL;
> +    virDomainObjPtr vm = NULL;
> +    int ret = -1;
> +
> +    virCheckFlags(0, -1);
> +
> +    if (!(vm = qemuDomObjFromDomain(dom)))
> +        goto cleanup;
> +
> +    if (!virDomainObjIsActive(vm)) {
> +        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
> +                        _("domain is not running"));
> +        goto cleanup;
> +    }
> +
> +    priv = vm->privateData;
> +
> +    if (virDomainInterfaceAddressesEnsureACL(dom->conn, vm->def) < 0)
> +        goto cleanup;
> +
> +    if (priv->agentError) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                        _("QEMU guest agent is not "
> +                          "available due to an error"));
> +        goto cleanup;
> +    }
> +
> +    if (!priv->agent) {
> +        virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
> +                        _("QEMU guest agent is not configured"));
> +        goto cleanup;
> +    }
> +
> +    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_QUERY) < 0)
> +        goto cleanup;
> +
> +    qemuDomainObjEnterAgent(vm);
> +    ret = qemuAgentGetInterfaces(priv->agent, ifaces);
> +    qemuDomainObjExitAgent(vm);
> +
> +    if (qemuDomainObjEndJob(driver, vm) == 0)
> +        vm = NULL;
> +
> +cleanup:
> +    if (vm)
> +        virObjectUnlock(vm);
> +    return ret;
> +}
>
>  static virDriver qemuDriver = {
>      .no = VIR_DRV_QEMU,
> @@ -15965,6 +16019,7 @@ static virDriver qemuDriver = {
>      .domainMemoryPeek = qemuDomainMemoryPeek, /* 0.4.4 */
>      .domainGetBlockInfo = qemuDomainGetBlockInfo, /* 0.8.1 */
>      .nodeGetCPUStats = qemuNodeGetCPUStats, /* 0.9.3 */
> +    .domainInterfaceAddresses = qemuDomainInterfaceAddresses, /* 1.1.3 */
>      .nodeGetMemoryStats = qemuNodeGetMemoryStats, /* 0.9.3 */
>      .nodeGetCellsFreeMemory = qemuNodeGetCellsFreeMemory, /* 0.4.4 */
>      .nodeGetFreeMemory = qemuNodeGetFreeMemory, /* 0.4.4 */
> diff --git a/tests/qemuagenttest.c b/tests/qemuagenttest.c
> index 4e27981..4014a09 100644
> --- a/tests/qemuagenttest.c
> +++ b/tests/qemuagenttest.c
> @@ -576,6 +576,154 @@ cleanup:
>      return ret;
>  }
>
> +static const char testQemuAgentGetInterfacesResponse[] =
> +    "{\"return\": "
> +    "    ["
> +    "       {\"name\":\"lo\","
> +    "        \"ip-addresses\":"
> +    "          ["
> +    "             {\"ip-address-type\":\"ipv4\","
> +    "              \"ip-address\":\"127.0.0.1\","
> +    "              \"prefix\":8"
> +    "             },"
> +    "             {\"ip-address-type\":\"ipv6\","
> +    "              \"ip-address\":\"::1\","
> +    "              \"prefix\":128"
> +    "             }"
> +    "          ],"
> +    "        \"hardware-address\":\"00:00:00:00:00:00\""
> +    "       },"
> +    "       {\"name\":\"eth0\","
> +    "        \"ip-addresses\":"
> +    "          ["
> +    "             {\"ip-address-type\":\"ipv4\","
> +    "              \"ip-address\":\"192.168.102.142\","
> +    "              \"prefix\":24"
> +    "             },"
> +    "             {\"ip-address-type\":\"ipv6\","
> +    "              \"ip-address\":\"fe80::5054:ff:fe89:ad35\","
> +    "              \"prefix\":64"
> +    "             },"
> +    "             {\"ip-address-type\":\"ipv4\","
> +    "              \"ip-address\":\"192.168.234.152\","
> +    "              \"prefix\":16"
> +    "             },"
> +    "             {\"ip-address-type\":\"ipv6\","
> +    "              \"ip-address\":\"fe80::5054:ff:fec3:68bb\","
> +    "              \"prefix\":64"
>
>
> Can qemu guest agent really returns mutiple same type IP addresses? Isn't it
> returning
> the other IP addresses as "iface:alias" ?

As I mentioned in the commit log, qemu-ga detects aliases created by both
the commands, ifconfig as well as as ip. In case of ip, alias name is
not created,
but a new IP is assigned to the interface and qemu-ga can detect this.
See the example output in the commit log of 4/5 of this series.

>
> +    "             }"
> +    "          ],"
> +    "        \"hardware-address\":\"52:54:00:89:ad:35\""
> +    "       },"
> +    "       {\"name\":\"eth1\","
> +    "        \"ip-addresses\":"
> +    "          ["
> +    "             {\"ip-address-type\":\"ipv4\","
> +    "              \"ip-address\":\"192.168.103.83\","
> +    "              \"prefix\":24"
> +    "             },"
> +    "             {\"ip-address-type\":\"ipv6\","
> +    "              \"ip-address\":\"fe80::5054:ff:fed3:39ee\","
> +    "              \"prefix\":64"
> +    "             }"
> +    "          ],"
> +    "        \"hardware-address\":\"52:54:00:d3:39:ee\""
> +    "       },"
> +    "       {\"name\":\"eth1:0\","
> +    "        \"ip-addresses\":"
> +    "          ["
> +    "             {\"ip-address-type\":\"ipv4\","
> +    "              \"ip-address\":\"192.168.10.91\","
> +    "              \"prefix\":24"
> +    "             },"
> +    "             {\"ip-address-type\":\"ipv6\","
> +    "              \"ip-address\":\"fe80::fc54:ff:fefe:4c4f\","
> +    "              \"prefix\":64"
> +    "             }"
> +    "          ],"
> +    "        \"hardware-address\":\"52:54:00:d3:39:ee\""
> +    "       },"
> +    "       {\"name\":\"eth2\","
> +    "        \"hardware-address\":\"52:54:00:36:2a:e5\""
> +    "       }"
> +    "    ]"
> +    "}";
> +
> +static int
> +testQemuAgentGetInterfaces(const void *data)
> +{
> +    virDomainXMLOptionPtr xmlopt = (virDomainXMLOptionPtr)data;
> +    qemuMonitorTestPtr test = qemuMonitorTestNewAgent(xmlopt);
> +    size_t i;
> +    int ret = -1;
> +    int ifaces_count = 0;
> +    virDomainInterfacePtr *ifaces = NULL;
> +
> +    if (!test)
> +        return -1;
> +
> +    if (qemuMonitorTestAddAgentSyncResponse(test) < 0)
> +        goto cleanup;
> +
> +    if (qemuMonitorTestAddItem(test, "guest-network-get-interfaces",
> +                               testQemuAgentGetInterfacesResponse) < 0)
> +        goto cleanup;
> +
> +    if ((ifaces_count =
> qemuAgentGetInterfaces(qemuMonitorTestGetAgent(test),
> +                                               &ifaces)) < 0)
> +        goto cleanup;
> +
> +    if (ifaces_count != 4) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       "expected 4 interfaces, got %d", ret);
> +        goto cleanup;
> +    }
> +
> +    if (ifaces[0]->naddrs != 2 ||
> +        ifaces[1]->naddrs != 4 ||
> +        ifaces[2]->naddrs != 4 ||
> +        ifaces[3]->naddrs != 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       "unexpected return value for number of IP
> addresses");
> +        goto cleanup;
> +    }
> +
> +    if (STRNEQ(ifaces[0]->name, "lo") ||
> +        STRNEQ(ifaces[0]->addrs[0].addr, "127.0.0.1") ||
> +        ifaces[0]->addrs[1].prefix != 128) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       "unexpected return values for interface: lo");
> +        goto cleanup;
> +    }
> +
> +    if (STRNEQ(ifaces[1]->hwaddr, "52:54:00:89:ad:35") ||
> +        ifaces[1]->addrs[0].prefix != 24 ||
> +        ifaces[1]->addrs[1].type != VIR_IP_ADDR_TYPE_IPV6) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       "unexpected return values for interface: eth0");
> +        goto cleanup;
> +    }
> +
> +    if (STRNEQ(ifaces[2]->name, "eth1") ||
> +        ifaces[2]->addrs[0].type != VIR_IP_ADDR_TYPE_IPV4 ||
> +        STRNEQ(ifaces[2]->addrs[1].addr, "fe80::5054:ff:fed3:39ee")) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       "unexpected return values for interface: eth1");
> +        goto cleanup;
> +    }
> +
> +    ret = 0;
> +
> +cleanup:
> +    qemuMonitorTestFree(test);
> +    if (ifaces) {
> +        for (i = 0; i < ifaces_count; i++)
> +            virDomainInterfaceFree(ifaces[i]);
> +    }
> +    VIR_FREE(ifaces);
> +
> +    return ret;
> +}
>
>  static int
>  mymain(void)
> @@ -605,6 +753,7 @@ mymain(void)
>      DO_TEST(Shutdown);
>      DO_TEST(CPU);
>      DO_TEST(ArbitraryCommand);
> +    DO_TEST(GetInterfaces);
>
>      DO_TEST(Timeout); /* Timeout should always be called last */
>
>
>



-- 
Nehal J Wani
IIIT-Hyderabad


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