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/*
 * lib/route/classifier.c       Classifier
 *
 *      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) 2003-2009 Thomas Graf <tgraf@suug.ch>
 */

/**
 * @ingroup tc
 * @defgroup cls Classifiers
 *
 * @par Classifier Identification
 * - protocol
 * - priority
 * - parent
 * - interface
 * - kind
 * - handle
 * 
 * @{
 */

#include <netlink-local.h>
#include <netlink-tc.h>
#include <netlink/netlink.h>
#include <netlink/utils.h>
#include <netlink/route/tc.h>
#include <netlink/route/classifier.h>
#include <netlink/route/classifier-modules.h>
#include <netlink/route/link.h>

static struct nl_cache_ops rtnl_cls_ops;

static int cls_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
                          struct nlmsghdr *nlh, struct nl_parser_param *pp)
{
        struct rtnl_cls_ops *cops;
        struct rtnl_cls *cls;
        int err;

        cls = rtnl_cls_alloc();
        if (!cls) {
                err = -NLE_NOMEM;
                goto errout;
        }
        cls->ce_msgtype = nlh->nlmsg_type;

        err = tca_msg_parser(nlh, (struct rtnl_tca *) cls);
        if (err < 0)
                goto errout_free;

        cls->c_prio = TC_H_MAJ(cls->c_info) >> 16;
        cls->c_protocol = ntohs(TC_H_MIN(cls->c_info));

        cops = rtnl_cls_lookup_ops(cls);
        if (cops && cops->co_msg_parser && (err = cops->co_msg_parser(cls)) < 0)
                goto errout_free;

        err = pp->pp_cb((struct nl_object *) cls, pp);
errout_free:
        rtnl_cls_put(cls);
errout:
        return err;
}

static int cls_request_update(struct nl_cache *cache, struct nl_sock *sk)
{
        struct tcmsg tchdr = {
                .tcm_family = AF_UNSPEC,
                .tcm_ifindex = cache->c_iarg1,
                .tcm_parent = cache->c_iarg2,
        };

        return nl_send_simple(sk, RTM_GETTFILTER, NLM_F_DUMP, &tchdr,
                              sizeof(tchdr));
}


static int cls_build(struct rtnl_cls *cls, int type, int flags,
                     struct nl_msg **result)
{
        struct rtnl_cls_ops *cops;
        int err, prio, proto;
        struct tcmsg *tchdr;

        err = tca_build_msg((struct rtnl_tca *) cls, type, flags, result);
        if (err < 0)
                return err;

        tchdr = nlmsg_data(nlmsg_hdr(*result));
        prio = rtnl_cls_get_prio(cls);
        proto = rtnl_cls_get_protocol(cls);
        tchdr->tcm_info = TC_H_MAKE(prio << 16, htons(proto));

        cops = rtnl_cls_lookup_ops(cls);
        if (cops && cops->co_get_opts) {
                struct nl_msg *opts;

                if (!(opts = nlmsg_alloc())) {
                        err = -NLE_NOMEM;
                        goto errout;
                }

                if (!(err = cops->co_get_opts(cls, opts)))
                        err = nla_put_nested(*result, TCA_OPTIONS, opts);

                nlmsg_free(opts);
                if (err < 0)
                        goto errout;
        }

        return 0;
errout:
        nlmsg_free(*result);
        return err;
}

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

/**
 * Build a netlink message to add a new classifier
 * @arg cls             classifier to add
 * @arg flags           additional netlink message flags
 * @arg result          Pointer to store resulting message.
 *
 * Builds a new netlink message requesting an addition of a classifier
 * The netlink message header isn't fully equipped with all relevant
 * fields and must be sent out via nl_send_auto_complete() or
 * supplemented as needed. \a classifier must contain the attributes of
 * the new classifier set via \c rtnl_cls_set_* functions. \a opts
 * may point to the clsasifier specific options.
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_cls_build_add_request(struct rtnl_cls *cls, int flags,
                               struct nl_msg **result)
{
        return cls_build(cls, RTM_NEWTFILTER, NLM_F_CREATE | flags, result);
}

/**
 * Add a new classifier
 * @arg sk              Netlink socket.
 * @arg cls             classifier to add
 * @arg flags           additional netlink message flags
 *
 * Builds a netlink message by calling rtnl_cls_build_add_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_cls_add(struct nl_sock *sk, struct rtnl_cls *cls, int flags)
{
        struct nl_msg *msg;
        int err;
        
        if ((err = rtnl_cls_build_add_request(cls, flags, &msg)) < 0)
                return err;
        
        err = nl_send_auto_complete(sk, msg);
        nlmsg_free(msg);
        if (err < 0)
                return err;

        return nl_wait_for_ack(sk);
}

/**
 * Build a netlink message to change classifier attributes
 * @arg cls             classifier 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_cls_build_change_request(struct rtnl_cls *cls, int flags,
                                  struct nl_msg **result)
{
        return cls_build(cls, RTM_NEWTFILTER, NLM_F_REPLACE | flags, result);
}

/**
 * Change a classifier
 * @arg sk              Netlink socket.
 * @arg cls             classifier to change
 * @arg flags           additional netlink message flags
 *
 * Builds a netlink message by calling rtnl_cls_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_cls_change(struct nl_sock *sk, struct rtnl_cls *cls, int flags)
{
        struct nl_msg *msg;
        int err;
        
        if ((err = rtnl_cls_build_change_request(cls, flags, &msg)) < 0)
                return err;
        
        err = nl_send_auto_complete(sk, msg);
        nlmsg_free(msg);
        if (err < 0)
                return err;

        return nl_wait_for_ack(sk);
}

/**
 * Build a netlink request message to delete a classifier
 * @arg cls             classifier to delete
 * @arg flags           additional netlink message flags
 * @arg result          Pointer to store resulting message.
 *
 * Builds a new netlink message requesting a deletion of a classifier.
 * 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_cls_build_delete_request(struct rtnl_cls *cls, int flags,
                                  struct nl_msg **result)
{
        return cls_build(cls, RTM_DELTFILTER, flags, result);
}


/**
 * Delete a classifier
 * @arg sk              Netlink socket.
 * @arg cls             classifier to delete
 * @arg flags           additional netlink message flags
 *
 * Builds a netlink message by calling rtnl_cls_build_delete_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_cls_delete(struct nl_sock *sk, struct rtnl_cls *cls, int flags)
{
        struct nl_msg *msg;
        int err;
        
        if ((err = rtnl_cls_build_delete_request(cls, flags, &msg)) < 0)
                return err;
        
        err = nl_send_auto_complete(sk, msg);
        nlmsg_free(msg);
        if (err < 0)
                return err;

        return nl_wait_for_ack(sk);
}

/** @} */

/**
 * @name Cache Management
 * @{
 */

/**
 * Build a classifier cache including all classifiers attached to the
 * specified class/qdisc on eht specified interface.
 * @arg sk              Netlink socket.
 * @arg ifindex         interface index of the link the classes are
 *                      attached to.
 * @arg parent          parent qdisc/class
 * @arg result          Pointer to store resulting cache.
 *
 * Allocates a new cache, initializes it properly and updates it to
 * include all classes attached to the specified interface.
 *
 * @note The caller is responsible for destroying and freeing the
 *       cache after using it.
 * @return 0 on success or a negative error code.
 */
int rtnl_cls_alloc_cache(struct nl_sock *sk, int ifindex, uint32_t parent,                       struct nl_cache **result)
{
        struct nl_cache * cache;
        int err;
        
        if (!(cache = nl_cache_alloc(&rtnl_cls_ops)))
                return -NLE_NOMEM;

        cache->c_iarg1 = ifindex;
        cache->c_iarg2 = parent;
        
        if (sk && (err = nl_cache_refill(sk, cache)) < 0) {
                nl_cache_free(cache);
                return err;
        }

        *result = cache;
        return 0;
}

/** @} */

static struct nl_cache_ops rtnl_cls_ops = {
        .co_name                = "route/cls",
        .co_hdrsize             = sizeof(struct tcmsg),
        .co_msgtypes            = {
                                        { RTM_NEWTFILTER, NL_ACT_NEW, "new" },
                                        { RTM_DELTFILTER, NL_ACT_DEL, "del" },
                                        { RTM_GETTFILTER, NL_ACT_GET, "get" },
                                        END_OF_MSGTYPES_LIST,
                                  },
        .co_protocol            = NETLINK_ROUTE,
        .co_request_update      = cls_request_update,
        .co_msg_parser          = cls_msg_parser,
        .co_obj_ops             = &cls_obj_ops,
};

static void __init cls_init(void)
{
        nl_cache_mngt_register(&rtnl_cls_ops);
}

static void __exit cls_exit(void)
{
        nl_cache_mngt_unregister(&rtnl_cls_ops);
}

/** @} */