[libvirt] [PATCH v3 06/36] util: add helper method for re-attaching a tap device to a bridge

[Cole Robinson]

On 3/19/19 8:46 AM, Daniel P. Berrangé wrote:
> Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> ---
>  src/libvirt_private.syms |  1 +
>  src/util/virnetdevtap.c  | 69 ++++++++++++++++++++++++++++++++++++++++
>  src/util/virnetdevtap.h  | 12 +++++++
>  3 files changed, 82 insertions(+)
> 
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index d9494a04bb..6f5a734fdb 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -2461,6 +2461,7 @@ virNetDevTapDelete;
>  virNetDevTapGetName;
>  virNetDevTapGetRealDeviceName;
>  virNetDevTapInterfaceStats;
> +virNetDevTapReattachBridge;
>  
>  
>  # util/virnetdevveth.h
> diff --git a/src/util/virnetdevtap.c b/src/util/virnetdevtap.c
> index 972f3405aa..0484c7c5a4 100644
> --- a/src/util/virnetdevtap.c
> +++ b/src/util/virnetdevtap.c
> @@ -553,6 +553,75 @@ virNetDevTapAttachBridge(const char *tapname,
>  }
>  
>  
> +/**
> + * virNetDevTapReattachBridge:
> + * @tapname: the tap interface name (or name template)
> + * @brname: the bridge name
> + * @macaddr: desired MAC address
> + * @virtPortProfile: bridge/port specific configuration
> + * @virtVlan: vlan tag info
> + * @mtu: requested MTU for port (or 0 for "default")
> + * @actualMTU: MTU actually set for port (after accounting for bridge's MTU)
> + *
> + * Ensures that the tap device (@tapname) is connected to the bridge
> + * (@brname), potentially removing it from any existing bridge that
> + * does not match.
> + *
> + * Returns 0 in case of success or -1 on failure
> + */
> +int
> +virNetDevTapReattachBridge(const char *tapname,
> +                           const char *brname,
> +                           const virMacAddr *macaddr,
> +                           const unsigned char *vmuuid,
> +                           virNetDevVPortProfilePtr virtPortProfile,
> +                           virNetDevVlanPtr virtVlan,
> +                           unsigned int mtu,
> +                           unsigned int *actualMTU)
> +{
> +    bool useOVS = false;
> +    char *master = NULL;
> +

Could use VIR_AUTOFREE to simplify things a bit

> +    if (virNetDevGetMaster(tapname, &master) < 0)
> +        return -1;
> +
> +    /* IFLA_MASTER for a tap on an OVS switch is always "ovs-system" */
> +    if (STREQ_NULLABLE(master, "ovs-system")) {
> +        useOVS = true;
> +        VIR_FREE(master);
> +        if (virNetDevOpenvswitchInterfaceGetMaster(tapname, &master) < 0)
> +            return -1;
> +    }
> +
> +    /* Nothing more todo if we're on the right bridge already */
> +    if (STREQ_NULLABLE(brname, master))
> +        return 0;
> +
> +    /* disconnect from current (incorrect) bridge, if any  */
> +    if (master) {
> +        int ret;
> +        VIR_INFO("Removing %s from %s", tapname, master);
> +        if (useOVS)
> +            ret = virNetDevOpenvswitchRemovePort(master, tapname);
> +        else
> +            ret = virNetDevBridgeRemovePort(master, tapname);
> +        VIR_FREE(master);
> +        if (ret < 0)
> +            return -1;
> +    }
> +

These were non-fatal in the original code. Is it okay to change?

Provided there's an answer:

Reviewed-by: Cole Robinson <crobinso at redhat.com>

- Cole