[libvirt] [PATCHv2 3/4] net-dhcp-leases: Private implementation inside network driver

Osier Yang jyang at redhat.com
Fri Sep 13 10:03:47 UTC 2013


On 13/09/13 05:53, Nehal J Wani wrote:
> By querying the driver for the path of the leases file for the given virtual
> network and parsing it to retrieve info.
>
> src/network/bridge_driver.c:
>    * Implement networkGetDHCPLeases
>    * Implement networkGetDHCPLeasesForMAC
>    * Implement networkGetDHCPLeasesHelper
>
> ---
>   src/network/bridge_driver.c | 193 ++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 193 insertions(+)
>
> diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
> index 3a8be90..2cdea56 100644
> --- a/src/network/bridge_driver.c
> +++ b/src/network/bridge_driver.c
> @@ -109,6 +109,36 @@ static int networkPlugBandwidth(virNetworkObjPtr net,
>                                   virDomainNetDefPtr iface);
>   static int networkUnplugBandwidth(virNetworkObjPtr net,
>                                     virDomainNetDefPtr iface);
> +/**
> + * VIR_NETWORK_DHCPLEASE_LENGTH_MAX:
> + *
> + * Macro providing the maximum length of an entry in the leases file
> + * Refer: http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2013q3/007402.html
> + */
> +#define VIR_NETWORK_DHCPLEASE_LENGTH_MAX 2048
> +
> +/**
> + * VIR_NETWORK_DHCPLEASE_PARAMS:
> + *
> + * Macro providing the maximum number of parameters in an entry in
> + * the leases file
> + */
> +#define VIR_NETWORK_DHCPLEASE_FIELDS 5

s/DHCPLEASE/DHCP_LEASE/,

> +
> +static int networkGetDHCPLeases(virNetworkPtr network,
> +                                virNetworkDHCPLeasesPtr **leases,
> +                                unsigned int flags);
> +
> +static int networkGetDHCPLeasesForMAC(virNetworkPtr network,
> +                                      const char *mac,
> +                                      virNetworkDHCPLeasesPtr **leases,
> +                                      unsigned int flags);
> +
> +static int networkGetDHCPLeasesHelper(virNetworkPtr network,
> +                                      virNetworkObjPtr obj,
> +                                      const char *mac,
> +                                      virNetworkDHCPLeasesPtr **leases,
> +                                      unsigned int flags);

Not a big deal, but these function declarations can be removed.

>   
>   static virNetworkDriverStatePtr driverState = NULL;
>   
> @@ -2980,6 +3010,167 @@ cleanup:
>       return ret;
>   }
>   
> +static int
> +networkGetDHCPLeases(virNetworkPtr network,
> +                     virNetworkDHCPLeasesPtr **leases,
> +                     unsigned int flags)
> +{
> +    int rv = -1;
> +    virNetworkObjPtr obj;
> +
> +    virCheckFlags(0, -1);
> +
> +    obj = networkObjFromNetwork(network);
> +
> +    if (virNetworkGetDHCPLeasesEnsureACL(network->conn, obj->def) < 0)
> +        goto cleanup;
> +
> +    rv = networkGetDHCPLeasesHelper(network, obj, NULL, leases, flags);
> +
> +cleanup:
> +    if (obj)
> +        virNetworkObjUnlock(obj);
> +    return rv;
> +}
> +
> +static int
> +networkGetDHCPLeasesForMAC(virNetworkPtr network,
> +                           const char *mac,
> +                           virNetworkDHCPLeasesPtr **leases,
> +                           unsigned int flags)
> +{
> +    int rv = -1;
> +    virNetworkObjPtr obj;
> +
> +    virCheckFlags(0, -1);
> +
> +    obj = networkObjFromNetwork(network);
> +
> +    if (virNetworkGetDHCPLeasesForMACEnsureACL(network->conn, obj->def) < 0)
> +        goto cleanup;
> +
> +    rv = networkGetDHCPLeasesHelper(network, obj, mac, leases, flags);
> +
> +cleanup:
> +    if (obj)
> +        virNetworkObjUnlock(obj);
> +    return rv;
> +}
> +
> +/* This function parese the leases file generated by dnsmasq.

s/generated by/of/,

> + * Example content:
> + * ::::::::::::::
> + * /var/lib/libvirt/dnsmasq/TestNetwork1.leases
> + * ::::::::::::::

Not good comment style, especially when the real comment has ":" character,
I'd like write it as:

* An example of leases file content:
*
* 1379024255    52:54:00:20:70:3d    192.168.105.240    *    *
* 1379023351    52:54:00:b1:70:19    192.168.105.201    *    *

> + * 1379024255 52:54:00:20:70:3d 192.168.105.240 * *
> + * 1379023351 52:54:00:b1:70:19 192.168.105.201 * *
> + */
> +static int
> +networkGetDHCPLeasesHelper(virNetworkPtr network,
> +                           virNetworkObjPtr obj,
> +                           const char *mac,
> +                           virNetworkDHCPLeasesPtr **leases,
> +                           unsigned int flags)
> +{
> +    int rv = -1;
> +    size_t i = 0;
> +    char *leasefile;
> +    FILE *fp = NULL;
> +    size_t nleases = 0;
> +    char **leaseparams;

To be consistent with the macro name, this should be lease_fields
or leasefields.

> +    virNetworkDHCPLeasesPtr *leases_ret = NULL;
> +    char dhcpentry[VIR_NETWORK_DHCPLEASE_LENGTH_MAX];

s/DHCPLEASE/DHCP_LEASE/,

> +
> +    virCheckFlags(0, -1);
> +

Redundant flags checking. You already did it in both networkGetDHCPLeases
and networkGetDHCPLeasesForMAC

> +    if (!network) {
> +        virReportError(VIR_ERR_NO_NETWORK, "%s",
> +                       _("no network with matching name"));
> +        return -1;
> +    }
> +
> +    /* Retrive leases file location */
> +    leasefile = networkDnsmasqLeaseFileNameDefault(network->name);
> +    if (!(fp = fopen(leasefile, "r"))) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("Unable to open leases file: %s"), leasefile);
> +        goto error;

s/error/cleanup/, since you don't have to free the lease_ret if fails
at this point.

> +    }
> +
> +    while (fgets(dhcpentry, sizeof(dhcpentry), fp) != NULL) {
> +        virNetworkDHCPLeasesPtr lease = NULL;
> +
> +        /* Remove newline */
> +        dhcpentry[strlen(dhcpentry) - 1] = '\0';
> +
> +        /* split the lease line */
> +        leaseparams = virStringSplit(dhcpentry, " ", VIR_NETWORK_DHCPLEASE_FIELDS);
> +
> +        if (virStringListLength(leaseparams) != VIR_NETWORK_DHCPLEASE_FIELDS) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR,
> +                           _("Number of lease params aren't equal to: %d"),
> +                           VIR_NETWORK_DHCPLEASE_FIELDS);
> +            goto error;
> +        }
> +
> +        if (mac && STRNEQ(mac, leaseparams[1]))
> +            continue;
> +
> +        /* We don't know the total number of leases yet */

This comment can be removed, it doesn't tell what the code does clearly,
instead, it's confused. The code explain itself clearly.

> +        if (VIR_EXPAND_N(leases_ret, nleases, 1) < 0)
> +            goto error;
> +
> +        if (VIR_ALLOC(leases_ret[nleases - 1]) < 0)
> +            goto error;
> +
> +        lease = leases_ret[nleases - 1];
> +
> +        /* Convert expirytime here */
> +        if (virStrToLong_ll(leaseparams[0], NULL, 10, &(lease->expirytime)) < 0) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR,
> +                           _("Unable to convert lease expiry time to integer: %s"),
> +                           leaseparams[0]);
> +            goto error;
> +        }
> +
> +        /* Hardcoded, as dnsmasq uses ipv4 */
> +        lease->type = VIR_IP_ADDR_TYPE_IPV4;
> +        lease->prefix = virSocketAddrGetNumNetmaskBits(&obj->def->ips->netmask);

Hm, virSocketAddrGetNumNetmaskBits is used as a general purpose function,
but its name is too specific. But it doesn't relate with this patch.

> +
> +        if ((VIR_STRDUP(lease->mac, leaseparams[1]) < 0) ||
> +            (VIR_STRDUP(lease->ipaddr, leaseparams[2]) < 0) ||
> +            (VIR_STRDUP(lease->hostname, leaseparams[3]) < 0) ||
> +            (VIR_STRDUP(lease->clientid, leaseparams[4]) < 0))
> +            goto error;
> +    }
> +
> +    if (mac && !leases_ret) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("no lease with matching MAC address: %s"), mac);
> +        goto error;
> +    }
> +
> +    if (leases_ret) {
> +        /* trim the array to the final size */

Confused comment, you are not trimming anything. Consider about:

/* NULL terminated array */

> +        ignore_value(VIR_REALLOC_N(leases_ret, nleases + 1));
> +        *leases = leases_ret;
> +        leases_ret = NULL;
> +        rv = nleases;
> +    }
> +
> +cleanup:
> +    VIR_FORCE_FCLOSE(fp);
> +    VIR_FREE(leasefile);
> +    return rv;
> +
> +error:
> +    if (leases_ret) {
> +        for (i = 0; i < nleases; i++)
> +            virNetworkDHCPLeaseFree(leases_ret[i]);
> +    }
> +    VIR_FREE(leases_ret);
> +    goto cleanup;
> +}
>   
>   static virNetworkDriver networkDriver = {
>       "Network",
> @@ -3004,6 +3195,8 @@ static virNetworkDriver networkDriver = {
>       .networkSetAutostart = networkSetAutostart, /* 0.2.1 */
>       .networkIsActive = networkIsActive, /* 0.7.3 */
>       .networkIsPersistent = networkIsPersistent, /* 0.7.3 */
> +    .networkGetDHCPLeases = networkGetDHCPLeases, /* 1.1.3 */
> +    .networkGetDHCPLeasesForMAC = networkGetDHCPLeasesForMAC, /* 1.1.3 */
>   };
>   
>   static virStateDriver networkStateDriver = {




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