bonding.c

/*
 * lib/route/link/bonding.c     Bonding Link Module
 *
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation version 2.1
 *      of the License.
 *
 * Copyright (c) 2011-2013 Thomas Graf <tgraf@suug.ch>
 */

/**
 * @ingroup link
 * @defgroup bonding Bonding
 *
 * @details
 * \b Link Type Name: "bond"
 *
 * @route_doc{link_bonding, Bonding Documentation}
 * @{
 */

#include <netlink-private/netlink.h>
#include <netlink/netlink.h>
#include <netlink-private/route/link/api.h>

/**
 * Allocate link object of type bond
 *
 * @return Allocated link object or NULL.
 */
struct rtnl_link *rtnl_link_bond_alloc(void)
{
        struct rtnl_link *link;
        int err;

        if (!(link = rtnl_link_alloc()))
                return NULL;

        if ((err = rtnl_link_set_type(link, "bond")) < 0) {
                rtnl_link_put(link);
                return NULL;
        }

        return link;
}

/**
 * Create a new kernel bonding device
 * @arg sock            netlink socket
 * @arg name            name of bonding device or NULL
 * @arg opts            bonding options (currently unused)
 *
 * Creates a new bonding device in the kernel. If no name is
 * provided, the kernel will automatically pick a name of the
 * form "type%d" (e.g. bond0, vlan1, etc.)
 *
 * The \a opts argument is currently unused. In the future, it
 * may be used to carry additional bonding options to be set
 * when creating the bonding device.
 *
 * @note When letting the kernel assign a name, it will become
 *       difficult to retrieve the interface afterwards because
 *       you have to guess the name the kernel has chosen. It is
 *       therefore not recommended to not provide a device name.
 *
 * @see rtnl_link_bond_enslave()
 * @see rtnl_link_bond_release()
 *
 * @return 0 on success or a negative error code
 */
int rtnl_link_bond_add(struct nl_sock *sock, const char *name,
                       struct rtnl_link *opts)
{
        struct rtnl_link *link;
        int err;

        if (!(link = rtnl_link_bond_alloc()))
                return -NLE_NOMEM;

        if (!name && opts)
                name = rtnl_link_get_name(opts);

        if (name)
                rtnl_link_set_name(link, name);

        err = rtnl_link_add(sock, link, NLM_F_CREATE);

        rtnl_link_put(link);

        return err;
}

/**
 * Add a link to a bond (enslave)
 * @arg sock            netlink socket
 * @arg master          ifindex of bonding master
 * @arg slave           ifindex of slave link to add to bond
 *
 * This function is identical to rtnl_link_bond_enslave() except that
 * it takes interface indices instead of rtnl_link objcets.
 *
 * @see rtnl_link_bond_enslave()
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_link_bond_enslave_ifindex(struct nl_sock *sock, int master,
                                   int slave)
{
        struct rtnl_link *link;
        int err;

        if (!(link = rtnl_link_bond_alloc()))
                return -NLE_NOMEM;

        rtnl_link_set_ifindex(link, slave);
        rtnl_link_set_master(link, master);
        
        if ((err = rtnl_link_change(sock, link, link, 0)) < 0)
                goto errout;

        rtnl_link_put(link);

        /*
         * Due to the kernel not signaling whether this opertion is
         * supported or not, we will retrieve the attribute to see  if the
         * request was successful. If the master assigned remains unchanged
         * we will return NLE_OPNOTSUPP to allow performing backwards
         * compatibility of some sort.
         */
        if ((err = rtnl_link_get_kernel(sock, slave, NULL, &link)) < 0)
                return err;

        if (rtnl_link_get_master(link) != master)
                err = -NLE_OPNOTSUPP;

errout:
        rtnl_link_put(link);

        return err;
}

/**
 * Add a link to a bond (enslave)
 * @arg sock            netlink socket
 * @arg master          bonding master
 * @arg slave           slave link to add to bond
 *
 * Constructs a RTM_NEWLINK or RTM_SETLINK message adding the slave to
 * the master and sends the request via the specified netlink socket.
 *
 * @note The feature of enslaving/releasing via netlink has only been added
 *       recently to the kernel (Feb 2011). Also, the kernel does not signal
 *       if the operation is not supported. Therefore this function will
 *       verify if the master assignment has changed and will return
 *       -NLE_OPNOTSUPP if it did not.
 *
 * @see rtnl_link_bond_enslave_ifindex()
 * @see rtnl_link_bond_release()
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_link_bond_enslave(struct nl_sock *sock, struct rtnl_link *master,
                           struct rtnl_link *slave)
{
        return rtnl_link_bond_enslave_ifindex(sock,
                                rtnl_link_get_ifindex(master),
                                rtnl_link_get_ifindex(slave));
}

/**
 * Release a link from a bond
 * @arg sock            netlink socket
 * @arg slave           slave link to be released
 *
 * This function is identical to rtnl_link_bond_release() except that
 * it takes an interface index instead of a rtnl_link object.
 *
 * @see rtnl_link_bond_release()
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_link_bond_release_ifindex(struct nl_sock *sock, int slave)
{
        return rtnl_link_bond_enslave_ifindex(sock, 0, slave);
}

/**
 * Release a link from a bond
 * @arg sock            netlink socket
 * @arg slave           slave link to be released
 *
 * Constructs a RTM_NEWLINK or RTM_SETLINK message releasing the slave from
 * its master and sends the request via the specified netlink socket.
 *
 * @note The feature of enslaving/releasing via netlink has only been added
 *       recently to the kernel (Feb 2011). Also, the kernel does not signal
 *       if the operation is not supported. Therefore this function will
 *       verify if the master assignment has changed and will return
 *       -NLE_OPNOTSUPP if it did not.
 *
 * @see rtnl_link_bond_release_ifindex()
 * @see rtnl_link_bond_enslave()
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_link_bond_release(struct nl_sock *sock, struct rtnl_link *slave)
{
        return rtnl_link_bond_release_ifindex(sock,
                                rtnl_link_get_ifindex(slave));
}

static struct rtnl_link_info_ops bonding_info_ops = {
        .io_name                = "bond",
};

static void __init bonding_init(void)
{
        rtnl_link_register_info(&bonding_info_ops);
}

static void __exit bonding_exit(void)
{
        rtnl_link_unregister_info(&bonding_info_ops);
}

/** @} */