[PATCH 1/2] util:netlink: Enable virNetlinkNewLink to support veth

[Laine Stump]

On 11/17/20 1:48 AM, Shi Lei wrote:
> Signed-off-by: Shi Lei <shi_lei at massclouds.com>
> ---
>   src/util/virnetlink.c | 25 +++++++++++++++++++++++++
>   src/util/virnetlink.h |  1 +
>   2 files changed, 26 insertions(+)
>
> diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
> index fdd3a6a4..e191f63b 100644
> --- a/src/util/virnetlink.c
> +++ b/src/util/virnetlink.c
> @@ -41,6 +41,18 @@ VIR_LOG_INIT("util.netlink");
>   #define NETLINK_ACK_TIMEOUT_S  (2*1000)
>   
>   #if defined(WITH_LIBNL)
> +
> +/*
> + * VETH_INFO_PEER is defined in libnl, but it isn't exposed.
> + * We include it just like what iproute2 has done.

This is actually defined as a part of the basic netlink .h files, and is 
available in /usr/include/linux/veth.h. The file in iproute2 is just a 
copy of that file (in include/uapi/linux/veth.h). I'm not sure why they 
did that, possibly so they could build an ip binary containing the "new" 
(at the time) veth support on a machine that was still lacking support 
in the kernel header files?.


Anyway, I replaced this open-coded definition of VETH_INFO_* with

#include <linux/veth.h> and everything built with no problem. And I've 
checked and that file is present in the kernel headers at least as far 
back as kernel-3.18 (and we don't support anything older than that).


So, when you send V2 with the change I outlined in my review of Patch 
2/2, could you replace this enum with the proper #include?


Thanks!

> + */
> +enum {
> +    VETH_INFO_UNSPEC,
> +    VETH_INFO_PEER,
> +
> +    __VETH_INFO_MAX
> +};
> +
>   /* State for a single netlink event handle */
>   struct virNetlinkEventHandle {
>       int watch;
> @@ -535,6 +547,19 @@ virNetlinkNewLink(const char *ifname,
>           NETLINK_MSG_NEST_END(nl_msg, infodata);
>       }
>   
> +    if (STREQ(type, "veth") && extra_args && extra_args->veth_peer) {
> +        struct nlattr *infoveth = NULL;
> +
> +        NETLINK_MSG_NEST_START(nl_msg, infodata, IFLA_INFO_DATA);
> +        NETLINK_MSG_NEST_START(nl_msg, infoveth, VETH_INFO_PEER);
> +        nlmsg_reserve(nl_msg, sizeof(struct ifinfomsg), 0);
> +        NETLINK_MSG_PUT(nl_msg, IFLA_IFNAME,
> +                        (strlen(extra_args->veth_peer) + 1),
> +                        extra_args->veth_peer);
> +        NETLINK_MSG_NEST_END(nl_msg, infoveth);
> +        NETLINK_MSG_NEST_END(nl_msg, infodata);
> +    }
> +
>       NETLINK_MSG_NEST_END(nl_msg, linkinfo);
>   
>       if (extra_args) {
> diff --git a/src/util/virnetlink.h b/src/util/virnetlink.h
> index 7121eac4..7c4ed202 100644
> --- a/src/util/virnetlink.h
> +++ b/src/util/virnetlink.h
> @@ -84,6 +84,7 @@ struct _virNetlinkNewLinkData {
>       const int *ifindex;             /* The index for the 'link' device */
>       const virMacAddr *mac;          /* The MAC address of the device */
>       const uint32_t *macvlan_mode;   /* The mode of macvlan */
> +    const char *veth_peer;          /* The peer name for veth */
>   };
>   
>   int virNetlinkNewLink(const char *ifname,