[lxc-devel] [PATCH 7/9] container: introduce two functions named as {at/de}tach_interface().

[Serge Hallyn]

Quoting Dongsheng Yang (yangds.fnst at cn.fujitsu.com):
> Currently, we depends on ip command to attach interface to container.
> It means we only implemented it by python.
> 
> This patch implement adding and removing interface by c and added
> them in struct container.
> 
> Signed-off-by: Dongsheng Yang <yangds.fnst at cn.fujitsu.com>

Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>

> ---
>  src/lxc/lxccontainer.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 86 insertions(+)
> 
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 47f60d9..67a7902 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -39,6 +39,7 @@
>  
>  #include <lxc/lxccontainer.h>
>  #include <lxc/version.h>
> +#include <lxc/network.h>
>  
>  #include "config.h"
>  #include "lxc.h"
> @@ -3426,6 +3427,89 @@ static bool lxcapi_remove_device_node(struct lxc_container *c, const char *src_p
>  	return add_remove_device_node(c, src_path, dest_path, false);
>  }
>  
> +static bool lxcapi_attach_interface(struct lxc_container *c, const char *ifname,
> +				const char *dst_ifname)
> +{
> +	int ret = 0;
> +	if (am_unpriv()) {
> +		ERROR(NOT_SUPPORTED_ERROR, __FUNCTION__);
> +		return false;
> +	}
> +
> +	ret = lxc_netdev_isup(ifname);
> +	if (ret < 0)
> +		goto err;
> +
> +	/* netdev of ifname is up. */
> +	if (ret) {
> +		ret = lxc_netdev_down(ifname);
> +		if (ret)
> +			goto err;
> +	}
> +
> +	ret = lxc_netdev_move_by_name(ifname, c->init_pid(c), dst_ifname);
> +	if (ret)
> +		goto err;
> +
> +	return true;
> +err:
> +	/* -EINVAL means there is no netdev named as ifanme. */
> +	if (ret == -EINVAL) {
> +		ERROR("No network device named as %s.", ifname);
> +	}
> +	return false;
> +}
> +
> +static bool lxcapi_detach_interface(struct lxc_container *c, const char *ifname,
> +					const char *dst_ifname)
> +{
> +	pid_t pid, pid_outside;
> +
> +	if (am_unpriv()) {
> +		ERROR(NOT_SUPPORTED_ERROR, __FUNCTION__);
> +		return false;
> +	}
> +
> +	pid_outside = getpid();
> +	pid = fork();
> +	if (pid < 0) {
> +		ERROR("failed to fork task to get interfaces information");
> +		return false;
> +	}
> +
> +	if (pid == 0) { // child
> +		int ret = 0;
> +		if (!enter_to_ns(c)) {
> +			ERROR("failed to enter namespace");
> +			exit(-1);
> +		}
> +
> +		ret = lxc_netdev_isup(ifname);
> +		if (ret < 0)
> +			exit(ret);
> +
> +		/* netdev of ifname is up. */
> +		if (ret) {
> +			ret = lxc_netdev_down(ifname);
> +			if (ret)
> +				exit(ret);
> +		}
> +
> +		ret = lxc_netdev_move_by_name(ifname, pid_outside, dst_ifname);
> +
> +		/* -EINVAL means there is no netdev named as ifanme. */
> +		if (ret == -EINVAL) {
> +			ERROR("No network device named as %s.", ifname);
> +		}
> +		exit(ret);
> +	}
> +
> +	if (wait_for_pid(pid) != 0)
> +		return false;
> +
> +	return true;
> +}
> +
>  struct criu_opts {
>  	/* The type of criu invocation, one of "dump" or "restore" */
>  	char *action;
> @@ -4051,6 +4135,8 @@ struct lxc_container *lxc_container_new(const char *name, const char *configpath
>  	c->may_control = lxcapi_may_control;
>  	c->add_device_node = lxcapi_add_device_node;
>  	c->remove_device_node = lxcapi_remove_device_node;
> +	c->attach_interface = lxcapi_attach_interface;
> +	c->detach_interface = lxcapi_detach_interface;
>  	c->checkpoint = lxcapi_checkpoint;
>  	c->restore = lxcapi_restore;
>  
> -- 
> 1.8.4.2
>