[lxc-devel] [PATCH 5/9] network: introduce a interface named lxc_netdev_isup().

[Dongsheng Yang]

On 09/17/2014 11:42 AM, Serge Hallyn wrote:
> Quoting Dongsheng Yang (yangds.fnst at cn.fujitsu.com):
>> When we need to know some info about a netdev, such as is_up or not,
>> we need to read the flag for the netdev.
>>
>> This patch introduce a interface function named lxc_netdev_isup()
>> to check is a netdev up or down.
>>
>> And introduce a network private function named netdev_get_flag()
>> to get flag for netdev by netlink.
>>
>> Signed-off-by: Dongsheng Yang <yangds.fnst at cn.fujitsu.com>
>> ---
>>   src/lxc/network.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   src/lxc/network.h |  2 ++
>>   2 files changed, 69 insertions(+)
>>
>> diff --git a/src/lxc/network.c b/src/lxc/network.c
>> index 4c577b1..e83b786 100644
>> --- a/src/lxc/network.c
>> +++ b/src/lxc/network.c
>> @@ -305,6 +305,73 @@ out:
>>   	return err;
>>   }
>>   
>> +int netdev_get_flag(const char* name, int *flag)
>> +{
>> +	struct nl_handler nlh;
>> +	struct nlmsg *nlmsg = NULL, *answer = NULL;
>> +	struct link_req *link_req;
>> +	int index, len, err;
>> +	struct ifinfomsg *ifi;
>> +
>> +	err = netlink_open(&nlh, NETLINK_ROUTE);
>> +	if (err)
>> +		return err;
>> +
>> +	err = -EINVAL;
>> +	len = strlen(name);
>> +	if (len == 1 || len >= IFNAMSIZ)
>> +		goto out;
>> +
>> +	err = -ENOMEM;
>> +	nlmsg = nlmsg_alloc(NLMSG_GOOD_SIZE);
>> +	if (!nlmsg)
>> +		goto out;
>> +
>> +	answer = nlmsg_alloc(NLMSG_GOOD_SIZE);
>> +	if (!answer)
>> +		goto out;
>> +
>> +	err = -EINVAL;
>> +	index = if_nametoindex(name);
>> +	if (!index)
>> +		goto out;
>> +
>> +	link_req = (struct link_req *)nlmsg;
>> +	link_req->ifinfomsg.ifi_family = AF_UNSPEC;
>> +	link_req->ifinfomsg.ifi_index = index;
>> +	nlmsg->nlmsghdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
>> +	nlmsg->nlmsghdr.nlmsg_flags = NLM_F_REQUEST;
>> +	nlmsg->nlmsghdr.nlmsg_type = RTM_GETLINK;
>> +
>> +	err = netlink_transaction(&nlh, nlmsg, answer);
>> +	if (err)
>> +		goto out;
>> +
>> +	ifi = NLMSG_DATA(answer);
>> +
>> +	*flag = ifi->ifi_flags;
>> +out:
>> +	netlink_close(&nlh);
>> +	nlmsg_free(nlmsg);
>> +	nlmsg_free(answer);
>> +	return err;
>> +}
>> +
>> +int lxc_netdev_isup(const char* name)
>> +{
>> +	int flag;
>> +	int err;
>> +
>> +	err = netdev_get_flag(name, &flag);
>> +	if (err)
>> +		goto out;
>> +	if (flag & IFF_UP)
>> +		return true;
>> +	return false;
> Don't return true/false in fns marked with int return type.
>
> Looks good otherwise.  Please resolve this however you prefer and
> resend.

Yes, I will fix it in V2. Thanx :)

Yang
>
>> +out:
>> +	return err;
>> +}
>> +
>>   int netdev_get_mtu(int ifindex)
>>   {
>>   	struct nl_handler nlh;
>> diff --git a/src/lxc/network.h b/src/lxc/network.h
>> index 768489d..cd42c8f 100644
>> --- a/src/lxc/network.h
>> +++ b/src/lxc/network.h
>> @@ -51,6 +51,8 @@ extern int netdev_set_flag(const char *name, int flag);
>>   /*
>>    * Set the device network up or down
>>    */
>> +
>> +extern int lxc_netdev_isup(const char *name);
>>   extern int lxc_netdev_up(const char *name);
>>   extern int lxc_netdev_down(const char *name);
>>   
>> -- 
>> 1.8.4.2
>>
> .
>