[libvirt] [PATCH 11/19] util: new functions virNetDev(Save|Read|Set)NetConfig()

[Michal Privoznik]

On 03/10/2017 09:35 PM, Laine Stump wrote:
> These three functions are destined to replace
> virNetDev(Replace|Restore)NetConfig() and
> virNetDev(Replace|Restore)MacAddress(), which both do the save and set
> together as a single step. We need to separate the save, read, and set
> steps because there will be situations where we need to do something
> else in between (in particular, we will need to rebind a VF's driver
> after save but before set).
>
> This patch creates the new functions, but doesn't call them - that
> will come in a subsequent patch.
> ---
>  src/libvirt_private.syms |   3 +
>  src/util/virnetdev.c     | 531 +++++++++++++++++++++++++++++++++++++++++++++++
>  src/util/virnetdev.h     |  22 ++
>  3 files changed, 556 insertions(+)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index e9705ae..c983438 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1998,6 +1998,7 @@ virNetDevIfStateTypeFromString;
>  virNetDevIfStateTypeToString;
>  virNetDevIsVirtualFunction;
>  virNetDevPFGetVF;
> +virNetDevReadNetConfig;
>  virNetDevReplaceMacAddress;
>  virNetDevReplaceNetConfig;
>  virNetDevRestoreMacAddress;
> @@ -2007,11 +2008,13 @@ virNetDevRxFilterFree;
>  virNetDevRxFilterModeTypeFromString;
>  virNetDevRxFilterModeTypeToString;
>  virNetDevRxFilterNew;
> +virNetDevSaveNetConfig;
>  virNetDevSetMAC;
>  virNetDevSetMTU;
>  virNetDevSetMTUFromDevice;
>  virNetDevSetName;
>  virNetDevSetNamespace;
> +virNetDevSetNetConfig;
>  virNetDevSetOnline;
>  virNetDevSetPromiscuous;
>  virNetDevSetRcvAllMulti;
> diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c
> index 49a11f3..feb5ba7 100644
> --- a/src/util/virnetdev.c
> +++ b/src/util/virnetdev.c
> @@ -1899,6 +1899,496 @@ virNetDevRestoreNetConfig(const char *linkdev, int vf, const char *stateDir)
>      return ret;
>  }
>
> +
> +/**
> + * virNetDevSaveNetConfig:
> + * @linkdev: name of the interface
> + * @vf: vf index if linkdev is a pf
> + * @stateDir: directory to store old net config
> + * @saveVlan: false if we shouldn't attempt to save vlan tag info
> + *            (eg for interfaces using 802.1Qbg, since it handles
> + *            vlan tags internally)
> + *
> + * Save current MAC address and (if linkdev itself is a VF, or if @vf
> + * >= 0) the "admin MAC address" and vlan tag the device described by
> + * @linkdev:@vf to @stateDir. (the "admin MAC address" is stored in
> + * the PF, and is what the VF MAC will be initialized to the next time
> + * its driver is reloaded (either on host or guest).
> + *
> + * File Name and Format:
> + *
> + *  If the device is a VF and we're allowed to save vlan tag info, the
> + *  file will be named ${pfDevName_vf#{vf} (e.g. "enp2s0f0_vf5") and
> + *  will contain 2 or 3 lines of text:
> + *
> + *      line 1 - admin MAC address
> + *      line 2 - vlan tag
> + *      line 3 - VF MAC address (or missing if VF has no host net driver)

I'd rather see a JSON format or something. This can bite us in the 
future. What are your thoughts?

> + *
> + *  If the device isn't a VF, or we're not allowed to save vlan tag
> + *  info, the file will be named ${linkdev} (e.g. "enp3s0f0") and will
> + *  contain a single line of text containing linkdev's MAC address.
> + *
> + * Returns 0 on success, -1 on failure
> + *
> + */
> +int
> +virNetDevSaveNetConfig(const char *linkdev, int vf,
> +                       const char *stateDir,
> +                       bool saveVlan)
> +{
> +    int ret = -1;
> +    const char *pfDevName = NULL;
> +    char *pfDevOrig = NULL;
> +    char *vfDevOrig = NULL;
> +    virMacAddr oldMAC = { 0 };

This causes a compile error for me. calling memset(&oldMAC, 0, 
sizeof(oldMAC)); solved it for me. Moreover, this variable will always 
be set before use. So your call wether to leave the initialization in or 
out.

> +    char MACStr[VIR_MAC_STRING_BUFLEN];
> +    int oldVlanTag = -1;
> +    char *filePath = NULL;
> +    char *fileStr = NULL;
> +    virBuffer buf = VIR_BUFFER_INITIALIZER;

Michal