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cls.c

/*
 * 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.
 */
00142 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.
 */
00160 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.
 */
00189 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.
 */
00207 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.
 */
00236 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.
 */
00255 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.
 */
00294 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);
}

/** @} */

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