fifo.c

/*
 * lib/route/sch/fifo.c         (p|b)fifo
 *
 *      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) 2003-2006 Thomas Graf <tgraf@suug.ch>
 */
 
/**
 * @ingroup qdisc_api
 * @defgroup fifo Packet/Bytes FIFO (pfifo/bfifo)
 * @brief
 *
 * The FIFO qdisc comes in two flavours:
 * @par bfifo (Byte FIFO)
 * Allows enqueuing until the currently queued volume in bytes exceeds
 * the configured limit.backlog contains currently enqueued volume in bytes.
 *
 * @par pfifo (Packet FIFO)
 * Allows enquueing until the currently queued number of packets
 * exceeds the configured limit.
 *
 * The configuration is exactly the same, the decision which of
 * the two variations is going to be used is made based on the
 * kind of the qdisc (rtnl_qdisc_set_kind()).
 * @{
 */
 
#include <netlink-local.h>
#include <netlink-tc.h>
#include <netlink/netlink.h>
#include <netlink/route/qdisc.h>
#include <netlink/route/qdisc-modules.h>
#include <netlink/route/sch/fifo.h>
#include <netlink/utils.h>
 
/** @cond SKIP */
#define SCH_FIFO_ATTR_LIMIT 1
/** @endcond */
 
static inline struct rtnl_fifo *fifo_qdisc(struct rtnl_qdisc *qdisc)
{
        return (struct rtnl_fifo *) qdisc->q_subdata;
}
 
static inline struct rtnl_fifo *fifo_alloc(struct rtnl_qdisc *qdisc)
{
        if (!qdisc->q_subdata)
                qdisc->q_subdata = calloc(1, sizeof(struct rtnl_fifo));
 
        return fifo_qdisc(qdisc);
}
 
static int fifo_msg_parser(struct rtnl_qdisc *qdisc)
{
        struct rtnl_fifo *fifo;
        struct tc_fifo_qopt *opt;
 
        if (qdisc->q_opts->d_size < sizeof(struct tc_fifo_qopt))
                return nl_error(EINVAL, "FIFO options size mismatch");
 
        fifo = fifo_alloc(qdisc);
        if (!fifo)
                return nl_errno(ENOMEM);
 
        opt = (struct tc_fifo_qopt *) qdisc->q_opts->d_data;
        fifo->qf_limit = opt->limit;
        fifo->qf_mask = SCH_FIFO_ATTR_LIMIT;
 
        return 0;
}
 
static void fifo_free_data(struct rtnl_qdisc *qdisc)
{
        free(qdisc->q_subdata);
}
 
static int pfifo_dump_brief(struct rtnl_qdisc *qdisc,
                            struct nl_dump_params *p, int line)
{
        struct rtnl_fifo *fifo = fifo_qdisc(qdisc);
 
        if (fifo)
                dp_dump(p, " limit %u packets", fifo->qf_limit);
 
        return line;
}
 
static int bfifo_dump_brief(struct rtnl_qdisc *qdisc,
                            struct nl_dump_params *p, int line)
{
        struct rtnl_fifo *fifo = fifo_qdisc(qdisc);
 
        if (fifo) {
                char *unit;
                double r;
 
                r = nl_cancel_down_bytes(fifo->qf_limit, &unit);
                dp_dump(p, " limit %.1f%s", r, unit);
        }
 
        return line;
}
 
static struct nl_msg *fifo_get_opts(struct rtnl_qdisc *qdisc)
{
        struct rtnl_fifo *fifo;
        struct tc_fifo_qopt opts;
        struct nl_msg *msg;
 
        fifo = fifo_qdisc(qdisc);
        if (!fifo || !(fifo->qf_mask & SCH_FIFO_ATTR_LIMIT))
                return NULL;
 
        msg = nlmsg_alloc();
        if (!msg)
                goto errout;
 
        memset(&opts, 0, sizeof(opts));
        opts.limit = fifo->qf_limit;
 
        if (nlmsg_append(msg, &opts, sizeof(opts), NL_DONTPAD) < 0)
                goto errout;
 
        return msg;
errout:
        nlmsg_free(msg);
        return NULL;
}
 
/**
 * @name Attribute Modification
 * @{
 */
 
/**
 * Set limit of FIFO qdisc.
 * @arg qdisc           FIFO qdisc to be modified.
 * @arg limit           New limit.
 * @return 0 on success or a negative error code.
 */
int rtnl_qdisc_fifo_set_limit(struct rtnl_qdisc *qdisc, int limit)
{
        struct rtnl_fifo *fifo;
        
        fifo = fifo_alloc(qdisc);
        if (!fifo)
                return nl_errno(ENOMEM);
                
        fifo->qf_limit = limit;
        fifo->qf_mask |= SCH_FIFO_ATTR_LIMIT;
 
        return 0;
}
 
/**
 * Get limit of a FIFO qdisc.
 * @arg qdisc           FIFO qdisc.
 * @return Numeric limit or a negative error code.
 */
int rtnl_qdisc_fifo_get_limit(struct rtnl_qdisc *qdisc)
{
        struct rtnl_fifo *fifo;
        
        fifo = fifo_qdisc(qdisc);
        if (fifo && fifo->qf_mask & SCH_FIFO_ATTR_LIMIT)
                return fifo->qf_limit;
        else
                return nl_errno(ENOMEM);
}
 
/** @} */
 
static struct rtnl_qdisc_ops pfifo_ops = {
        .qo_kind                = "pfifo",
        .qo_msg_parser          = fifo_msg_parser,
        .qo_free_data           = fifo_free_data,
        .qo_dump[NL_DUMP_BRIEF] = pfifo_dump_brief,
        .qo_get_opts            = fifo_get_opts,
};
 
static struct rtnl_qdisc_ops bfifo_ops = {
        .qo_kind                = "bfifo",
        .qo_msg_parser          = fifo_msg_parser,
        .qo_free_data           = fifo_free_data,
        .qo_dump[NL_DUMP_BRIEF] = bfifo_dump_brief,
        .qo_get_opts            = fifo_get_opts,
};
 
static void __init fifo_init(void)
{
        rtnl_qdisc_register(&pfifo_ops);
        rtnl_qdisc_register(&bfifo_ops);
}
 
static void __exit fifo_exit(void)
{
        rtnl_qdisc_unregister(&pfifo_ops);
        rtnl_qdisc_unregister(&bfifo_ops);
}
 
/** @} */