act.c

/*
 * lib/route/act.c       Action
 *
 *      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) 2013 Cong Wang <xiyou.wangcong@gmail.com>
 */

/**
 * @ingroup tc
 * @defgroup act Action
 * @{
 */

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


static struct nl_object_ops act_obj_ops;
static struct nl_cache_ops rtnl_act_ops;

int rtnl_act_append(struct rtnl_act **head, struct rtnl_act *new)
{
        struct rtnl_act *p_act;
        int count = 1;

        if (*head == NULL) {
                *head = new;
                return 0;
        }

        p_act = *head;
        while (p_act->a_next) {
                ++count;
                p_act = p_act->a_next;
        }

        if (count > TCA_ACT_MAX_PRIO)
                return -NLE_RANGE;

        p_act->a_next = new;
        return 0;
}

int rtnl_act_remove(struct rtnl_act **head, struct rtnl_act *act)
{
        struct rtnl_act *a, **ap;

        for (ap = head; (a = *ap) != NULL; ap = &a->a_next)
                if (a == act)
                        break;
        if (a) {
                *ap = a->a_next;
                a->a_next = NULL;
                return 0;
        }

        return -NLE_OBJ_NOTFOUND;
}

static int rtnl_act_fill_one(struct nl_msg *msg, struct rtnl_act *act, int order)
{
        struct rtnl_tc *tc = TC_CAST(act);
        struct rtnl_tc_ops *ops;
        struct nlattr *nest;
        int err = -NLE_NOMEM;

        nest = nla_nest_start(msg, order);
        if (!nest)
                goto nla_put_failure;

        if (tc->ce_mask & TCA_ATTR_KIND)
            NLA_PUT_STRING(msg, TCA_ACT_KIND, tc->tc_kind);

        ops = rtnl_tc_get_ops(tc);
        if (ops && (ops->to_msg_fill || ops->to_msg_fill_raw)) {
                struct nlattr *opts;
                void *data = rtnl_tc_data(tc);

                if (ops->to_msg_fill) {
                        if (!(opts = nla_nest_start(msg, TCA_ACT_OPTIONS)))
                                goto nla_put_failure;

                        if ((err = ops->to_msg_fill(tc, data, msg)) < 0)
                                goto nla_put_failure;

                        nla_nest_end(msg, opts);
                } else if ((err = ops->to_msg_fill_raw(tc, data, msg)) < 0)
                        goto nla_put_failure;
        }
        nla_nest_end(msg, nest);
        return 0;

nla_put_failure:
        return err;
}

int rtnl_act_fill(struct nl_msg *msg, int attrtype, struct rtnl_act *act)
{
        struct rtnl_act *p_act = act;
        struct nlattr *nest;
        int err, order = 0;

        nest = nla_nest_start(msg, attrtype);
        if (!nest)
                return -NLE_MSGSIZE;

        while (p_act) {
                err = rtnl_act_fill_one(msg, p_act, ++order);
                if (err)
                        return err;
                p_act = p_act->a_next;
        }

        nla_nest_end(msg, nest);
        return 0;
}

static int rtnl_act_msg_build(struct rtnl_act *act, int type, int flags,
                      struct nl_msg **result)
{
        struct nl_msg *msg;
        struct tcamsg tcahdr = {
                .tca_family = AF_UNSPEC,
        };
        int err = -NLE_MSGSIZE;

        msg = nlmsg_alloc_simple(type, flags);
        if (!msg)
                return -NLE_NOMEM;

        if (nlmsg_append(msg, &tcahdr, sizeof(tcahdr), NLMSG_ALIGNTO) < 0)
                goto nla_put_failure;

        err = rtnl_act_fill(msg, TCA_ACT_TAB, act);
        if (err < 0)
                goto nla_put_failure;

        *result = msg;
        return 0;

nla_put_failure:
        nlmsg_free(msg);
        return err;
}

static int act_build(struct rtnl_act *act, int type, int flags,
                     struct nl_msg **result)
{
        int err;

        err = rtnl_act_msg_build(act, type, flags, result);
        if (err < 0)
                return err;
        return 0;
}

/**
 * @name Allocation/Freeing
 * @{
 */

struct rtnl_act *rtnl_act_alloc(void)
{
        struct rtnl_tc *tc;

        tc = TC_CAST(nl_object_alloc(&act_obj_ops));
        if (tc)
                tc->tc_type = RTNL_TC_TYPE_ACT;

        return (struct rtnl_act *) tc;
}

void rtnl_act_put(struct rtnl_act *act)
{
        nl_object_put((struct nl_object *) act);
}

/** @} */

/**
 * @name Addition/Modification/Deletion
 * @{
 */

/**
 * Build a netlink message requesting the addition of an action
 * @arg act             Action to add
 * @arg flags           Additional netlink message flags
 * @arg result          Pointer to store resulting netlink message
 *
 * The behaviour of this function is identical to rtnl_act_add() with
 * the exception that it will not send the message but return it int the
 * provided return pointer instead.
 *
 * @see rtnl_act_add()
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_act_build_add_request(struct rtnl_act *act, int flags,
                               struct nl_msg **result)
{
        return act_build(act, RTM_NEWACTION, flags, result);
}

/**
 * Add/Update action
 * @arg sk              Netlink socket
 * @arg act             Action to add/update
 * @arg flags           Additional netlink message flags
 *
 * Builds a \c RTM_NEWACTION netlink message requesting the addition
 * of a new action and sends the message to the kernel. The
 * configuration of the action is derived from the attributes of
 * the specified traffic class.
 *
 * The following flags may be specified:
 *  - \c NLM_F_CREATE:  Create action if it does not exist,
 *                      otherwise -NLE_OBJ_NOTFOUND is returned.
 *  - \c NLM_F_EXCL:    Return -NLE_EXISTS if an action with
 *                      matching handle exists already.
 *
 * Existing actions with matching handles will be updated, unless
 * the flag \c NLM_F_EXCL is specified. If no matching action
 * exists, it will be created if the flag \c NLM_F_CREATE is set,
 * otherwise the error -NLE_OBJ_NOTFOUND is returned.
 *
 * If the parent qdisc does not support classes, the error
 * \c NLE_OPNOTSUPP is returned.
 *
 * After sending, the function will wait for the ACK or an eventual
 * error message to be received and will therefore block until the
 * operation has been completed.
 *
 * @note Disabling auto-ack (nl_socket_disable_auto_ack()) will cause
 *       this function to return immediately after sending. In this case,
 *       it is the responsibility of the caller to handle any error
 *       messages returned.
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_act_add(struct nl_sock *sk, struct rtnl_act *act, int flags)
{
        struct nl_msg *msg;
        int err;

        if ((err = rtnl_act_build_add_request(act, flags, &msg)) < 0)
                return err;

        return nl_send_sync(sk, msg);
}

/**
 * Build a netlink message to change action attributes
 * @arg act             Action to change
 * @arg flags           additional netlink message flags
 * @arg result          Pointer to store resulting message.
 *
 * Builds a new netlink message requesting a change of a neigh
 * attributes. The netlink message header isn't fully equipped with
 * all relevant fields and must thus be sent out via nl_send_auto_complete()
 * or supplemented as needed.
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_act_build_change_request(struct rtnl_act *act, int flags,
                                  struct nl_msg **result)
{
        return act_build(act, RTM_NEWACTION, NLM_F_REPLACE | flags, result);
}

/**
 * Change an action
 * @arg sk              Netlink socket.
 * @arg act             action to change
 * @arg flags           additional netlink message flags
 *
 * Builds a netlink message by calling rtnl_act_build_change_request(),
 * sends the request to the kernel and waits for the next ACK to be
 * received and thus blocks until the request has been processed.
 *
 * @return 0 on sucess or a negative error if an error occured.
 */
int rtnl_act_change(struct nl_sock *sk, struct rtnl_act *act, int flags)
{
        struct nl_msg *msg;
        int err;

        if ((err = rtnl_act_build_change_request(act, flags, &msg)) < 0)
                return err;

        return nl_send_sync(sk, msg);
}

/**
 * Build netlink message requesting the deletion of an action
 * @arg act             Action to delete
 * @arg flags           Additional netlink message flags
 * @arg result          Pointer to store resulting netlink message
 *
 * The behaviour of this function is identical to rtnl_act_delete() with
 * the exception that it will not send the message but return it in the
 * provided return pointer instead.
 *
 * @see rtnl_act_delete()
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_act_build_delete_request(struct rtnl_act *act, int flags,
                                  struct nl_msg **result)
{
        return act_build(act, RTM_DELACTION, flags, result);
}

/**
 * Delete action
 * @arg sk              Netlink socket
 * @arg act             Action to delete
 * @arg flags           Additional netlink message flags
 *
 * Builds a \c RTM_DELACTION netlink message requesting the deletion
 * of an action and sends the message to the kernel.
 *
 * The message is constructed out of the following attributes:
 * - \c ifindex (required)
 * - \c prio (required)
 * - \c protocol (required)
 * - \c handle (required)
 * - \c parent (optional, if not specified parent equals root-qdisc)
 * - \c kind (optional, must match if provided)
 *
 * All other action attributes including all class type specific
 * attributes are ignored.
 *
 * After sending, the function will wait for the ACK or an eventual
 * error message to be received and will therefore block until the
 * operation has been completed.
 *
 * @note Disabling auto-ack (nl_socket_disable_auto_ack()) will cause
 *       this function to return immediately after sending. In this case,
 *       it is the responsibility of the caller to handle any error
 *       messages returned.
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_act_delete(struct nl_sock *sk, struct rtnl_act *act, int flags)
{
        struct nl_msg *msg;
        int err;

        if ((err = rtnl_act_build_delete_request(act, flags, &msg)) < 0)
                return err;

        return nl_send_sync(sk, msg);
}

/** @} */

static void act_dump_line(struct rtnl_tc *tc, struct nl_dump_params *p)
{
}

void rtnl_act_put_all(struct rtnl_act **head)
{
        struct rtnl_act *curr, *next;

        curr = *head;
        while (curr) {
                next = curr->a_next;
                rtnl_act_put(curr);
                curr = next;
        }
        *head = NULL;
}

int rtnl_act_parse(struct rtnl_act **head, struct nlattr *tb)
{
        struct rtnl_tc_ops *ops;
        struct nlattr *tb2[TCA_ACT_MAX + 1];
        struct nlattr *nla[TCA_ACT_MAX_PRIO + 1];
        char kind[TCKINDSIZ];
        int err, i;

        err = nla_parse(nla, TCA_ACT_MAX_PRIO, nla_data(tb),
                        NLMSG_ALIGN(nla_len(tb)), NULL);
        if (err < 0)
                return err;

        for (i = 1; i <= TCA_ACT_MAX_PRIO && nla[i]; i++) {
                struct rtnl_act *act;
                struct rtnl_tc *tc;

                act = rtnl_act_alloc();
                if (!act) {
                        err = -NLE_NOMEM;
                        goto err_free;
                }
                tc = TC_CAST(act);
                err = nla_parse(tb2, TCA_ACT_MAX, nla_data(nla[i]),
                                nla_len(nla[i]), NULL);
                if (err < 0)
                        goto err_free;

                if (tb2[TCA_ACT_KIND] == NULL) {
                        err = -NLE_MISSING_ATTR;
                        goto err_free;
                }

                nla_strlcpy(kind, tb2[TCA_ACT_KIND], sizeof(kind));
                rtnl_tc_set_kind(tc, kind);

                if (tb2[TCA_ACT_OPTIONS]) {
                        tc->tc_opts = nl_data_alloc_attr(tb2[TCA_ACT_OPTIONS]);
                        if (!tc->tc_opts) {
                                err = -NLE_NOMEM;
                                goto err_free;
                        }
                        tc->ce_mask |= TCA_ATTR_OPTS;
                }

                ops = rtnl_tc_get_ops(tc);
                if (ops && ops->to_msg_parser) {
                        void *data = rtnl_tc_data(tc);

                        if (!data) {
                                err = -NLE_NOMEM;
                                goto err_free;
                        }

                        err = ops->to_msg_parser(tc, data);
                        if (err < 0)
                                goto err_free;
                }
                err = rtnl_act_append(head, act);
                if (err < 0)
                        goto err_free;
        }
        return 0;

err_free:
        rtnl_act_put_all(head);

        return err;
}

static int rtnl_act_msg_parse(struct nlmsghdr *n, struct rtnl_act **act)
{
        struct rtnl_tc *tc = TC_CAST(act);
        struct nl_cache *link_cache;
        struct nlattr *tb[TCAA_MAX + 1];
        struct tcamsg *tm;
        int err;

        tc->ce_msgtype = n->nlmsg_type;

        err = nlmsg_parse(n, sizeof(*tm), tb, TCAA_MAX, NULL);
        if (err < 0)
                return err;

        tm = nlmsg_data(n);
        tc->tc_family  = tm->tca_family;

        if (tb[TCA_ACT_TAB] == NULL)
                return -NLE_MISSING_ATTR;

        err = rtnl_act_parse(act, tb[TCA_ACT_TAB]);
        if (err < 0)
                return err;

        if ((link_cache = __nl_cache_mngt_require("route/link"))) {
                struct rtnl_link *link;

                if ((link = rtnl_link_get(link_cache, tc->tc_ifindex))) {
                        rtnl_tc_set_link(tc, link);

                        /* rtnl_tc_set_link incs refcnt */
                        rtnl_link_put(link);
                }
        }

        return 0;
}
static int act_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
                          struct nlmsghdr *nlh, struct nl_parser_param *pp)
{
        struct rtnl_act *act, *p_act;
        int err;

        if (!(act = rtnl_act_alloc()))
                return -NLE_NOMEM;

        if ((err = rtnl_act_msg_parse(nlh, &act)) < 0)
                goto errout;

        p_act = act;
        while(p_act) {
                err = pp->pp_cb(OBJ_CAST(act), pp);
                if (err)
                        break;
                p_act = p_act->a_next;
        }
errout:
        rtnl_act_put(act);

        return err;
}

static int act_request_update(struct nl_cache *cache, struct nl_sock *sk)
{
        struct tcamsg tcahdr = {
                .tca_family = AF_UNSPEC,
        };

        return nl_send_simple(sk, RTM_GETACTION, NLM_F_DUMP, &tcahdr,
                              sizeof(tcahdr));
}

static struct rtnl_tc_type_ops act_ops = {
        .tt_type                = RTNL_TC_TYPE_ACT,
        .tt_dump_prefix         = "act",
        .tt_dump = {
                [NL_DUMP_LINE]  = act_dump_line,
        },
};

static struct nl_cache_ops rtnl_act_ops = {
        .co_name                = "route/act",
        .co_hdrsize             = sizeof(struct tcmsg),
        .co_msgtypes            = {
                                        { RTM_NEWACTION, NL_ACT_NEW, "new" },
                                        { RTM_DELACTION, NL_ACT_DEL, "del" },
                                        { RTM_GETACTION, NL_ACT_GET, "get" },
                                        END_OF_MSGTYPES_LIST,
                                  },
        .co_protocol            = NETLINK_ROUTE,
        .co_request_update      = act_request_update,
        .co_msg_parser          = act_msg_parser,
        .co_obj_ops             = &act_obj_ops,
};

static struct nl_object_ops act_obj_ops = {
        .oo_name                = "route/act",
        .oo_size                = sizeof(struct rtnl_act),
        .oo_free_data           = rtnl_tc_free_data,
        .oo_clone               = rtnl_tc_clone,
        .oo_dump = {
            [NL_DUMP_LINE]      = rtnl_tc_dump_line,
            [NL_DUMP_DETAILS]   = rtnl_tc_dump_details,
            [NL_DUMP_STATS]     = rtnl_tc_dump_stats,
        },
        .oo_compare             = rtnl_tc_compare,
        .oo_id_attrs            = (TCA_ATTR_IFINDEX | TCA_ATTR_HANDLE),
};

static void __init act_init(void)
{
        rtnl_tc_type_register(&act_ops);
        nl_cache_mngt_register(&rtnl_act_ops);
}

static void __exit act_exit(void)
{
        nl_cache_mngt_unregister(&rtnl_act_ops);
        rtnl_tc_type_unregister(&act_ops);
}

/** @} */