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tc.c

/*
 * lib/route/tc.c       Traffic Control
 *
 *    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) 2003-2008 Thomas Graf <tgraf@suug.ch>
 */

/**
 * @ingroup rtnl
 * @defgroup tc Traffic Control
 * @brief
 * @{
 */

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

/** @cond SKIP */

static struct nla_policy tc_policy[TCA_MAX+1] = {
      [TCA_KIND]  = { .type = NLA_STRING,
                      .maxlen = TCKINDSIZ },
      [TCA_STATS] = { .minlen = sizeof(struct tc_stats) },
      [TCA_STATS2]      = { .type = NLA_NESTED },
};

int tca_parse(struct nlattr **tb, int maxattr, struct rtnl_tca *g,
            struct nla_policy *policy)
{
      
      if (g->ce_mask & TCA_ATTR_OPTS)
            return nla_parse(tb, maxattr,
                         (struct nlattr *) g->tc_opts->d_data,
                         g->tc_opts->d_size, policy);
      else {
            /* Ugly but tb[] must be in a defined state even if no
             * attributes can be found. */
            memset(tb, 0, sizeof(struct nlattr *) * (maxattr + 1));
            return 0;
      }
}

static struct nla_policy tc_stats2_policy[TCA_STATS_MAX+1] = {
      [TCA_STATS_BASIC]    = { .minlen = sizeof(struct gnet_stats_basic) },
      [TCA_STATS_RATE_EST] = { .minlen = sizeof(struct gnet_stats_rate_est) },
      [TCA_STATS_QUEUE]    = { .minlen = sizeof(struct gnet_stats_queue) },
};

int tca_msg_parser(struct nlmsghdr *n, struct rtnl_tca *g)
{
      struct nlattr *tb[TCA_MAX + 1];
      struct tcmsg *tm;
      int err;

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

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

      nla_strlcpy(g->tc_kind, tb[TCA_KIND], TCKINDSIZ);

      tm = nlmsg_data(n);
      g->tc_family  = tm->tcm_family;
      g->tc_ifindex = tm->tcm_ifindex;
      g->tc_handle  = tm->tcm_handle;
      g->tc_parent  = tm->tcm_parent;
      g->tc_info    = tm->tcm_info;

      g->ce_mask = (TCA_ATTR_FAMILY | TCA_ATTR_IFINDEX | TCA_ATTR_HANDLE |
                  TCA_ATTR_PARENT | TCA_ATTR_INFO | TCA_ATTR_KIND);

      if (tb[TCA_OPTIONS]) {
            g->tc_opts = nl_data_alloc_attr(tb[TCA_OPTIONS]);
            if (!g->tc_opts)
                  return -NLE_NOMEM;
            g->ce_mask |= TCA_ATTR_OPTS;
      }
      

      if (tb[TCA_STATS2]) {
            struct nlattr *tbs[TCA_STATS_MAX + 1];

            err = nla_parse_nested(tbs, TCA_STATS_MAX, tb[TCA_STATS2],
                               tc_stats2_policy);
            if (err < 0)
                  return err;

            if (tbs[TCA_STATS_BASIC]) {
                  struct gnet_stats_basic *bs;
                  
                  bs = nla_data(tbs[TCA_STATS_BASIC]);
                  g->tc_stats[RTNL_TC_BYTES]    = bs->bytes;
                  g->tc_stats[RTNL_TC_PACKETS]  = bs->packets;
            }

            if (tbs[TCA_STATS_RATE_EST]) {
                  struct gnet_stats_rate_est *re;

                  re = nla_data(tbs[TCA_STATS_RATE_EST]);
                  g->tc_stats[RTNL_TC_RATE_BPS] = re->bps;
                  g->tc_stats[RTNL_TC_RATE_PPS] = re->pps;
            }
            
            if (tbs[TCA_STATS_QUEUE]) {
                  struct gnet_stats_queue *q;

                  q = nla_data(tbs[TCA_STATS_QUEUE]);
                  g->tc_stats[RTNL_TC_QLEN]     = q->qlen;
                  g->tc_stats[RTNL_TC_BACKLOG]  = q->backlog;
                  g->tc_stats[RTNL_TC_DROPS]    = q->drops;
                  g->tc_stats[RTNL_TC_REQUEUES] = q->requeues;
                  g->tc_stats[RTNL_TC_OVERLIMITS]     = q->overlimits;
            }

            g->ce_mask |= TCA_ATTR_STATS;
            
            if (tbs[TCA_STATS_APP]) {
                  g->tc_xstats = nl_data_alloc_attr(tbs[TCA_STATS_APP]);
                  if (g->tc_xstats == NULL)
                        return -NLE_NOMEM;
            } else
                  goto compat_xstats;
      } else {
            if (tb[TCA_STATS]) {
                  struct tc_stats *st = nla_data(tb[TCA_STATS]);

                  g->tc_stats[RTNL_TC_BYTES]    = st->bytes;
                  g->tc_stats[RTNL_TC_PACKETS]  = st->packets;
                  g->tc_stats[RTNL_TC_RATE_BPS] = st->bps;
                  g->tc_stats[RTNL_TC_RATE_PPS] = st->pps;
                  g->tc_stats[RTNL_TC_QLEN]     = st->qlen;
                  g->tc_stats[RTNL_TC_BACKLOG]  = st->backlog;
                  g->tc_stats[RTNL_TC_DROPS]    = st->drops;
                  g->tc_stats[RTNL_TC_OVERLIMITS]     = st->overlimits;

                  g->ce_mask |= TCA_ATTR_STATS;
            }

compat_xstats:
            if (tb[TCA_XSTATS]) {
                  g->tc_xstats = nl_data_alloc_attr(tb[TCA_XSTATS]);
                  if (g->tc_xstats == NULL)
                        return -NLE_NOMEM;
                  g->ce_mask |= TCA_ATTR_XSTATS;
            }
      }


      return 0;
}

void tca_free_data(struct rtnl_tca *tca)
{
      nl_data_free(tca->tc_opts);
      nl_data_free(tca->tc_xstats);
}

int tca_clone(struct rtnl_tca *dst, struct rtnl_tca *src)
{
      if (src->tc_opts) {
            dst->tc_opts = nl_data_clone(src->tc_opts);
            if (!dst->tc_opts)
                  return -NLE_NOMEM;
      }
      
      if (src->tc_xstats) {
            dst->tc_xstats = nl_data_clone(src->tc_xstats);
            if (!dst->tc_xstats)
                  return -NLE_NOMEM;
      }

      return 0;
}

void tca_dump_line(struct rtnl_tca *g, const char *type,
               struct nl_dump_params *p)
{
      char handle[32], parent[32];
      struct nl_cache *link_cache;
      
      link_cache = nl_cache_mngt_require("route/link");

      nl_dump_line(p, "%s %s ", g->tc_kind, type);

      if (link_cache) {
            char buf[32];
            nl_dump(p, "dev %s ",
                  rtnl_link_i2name(link_cache, g->tc_ifindex,
                               buf, sizeof(buf)));
      } else
            nl_dump(p, "dev %u ", g->tc_ifindex);
      
      nl_dump(p, "handle %s parent %s",
            rtnl_tc_handle2str(g->tc_handle, handle, sizeof(handle)),
            rtnl_tc_handle2str(g->tc_parent, parent, sizeof(parent)));
}

void tca_dump_details(struct rtnl_tca *g, struct nl_dump_params *p)
{
      nl_dump_line(p, "  ");
}

void tca_dump_stats(struct rtnl_tca *g, struct nl_dump_params *p)
{
      char *unit, fmt[64];
      float res;
      strcpy(fmt, "        %7.2f %s %10u %10u %10u %10u %10u\n");

      nl_dump_line(p, 
            "    Stats:    bytes    packets      drops overlimits" \
            "       qlen    backlog\n");

      res = nl_cancel_down_bytes(g->tc_stats[RTNL_TC_BYTES], &unit);
      if (*unit == 'B')
            fmt[11] = '9';

      nl_dump_line(p, fmt, res, unit,
            g->tc_stats[RTNL_TC_PACKETS],
            g->tc_stats[RTNL_TC_DROPS],
            g->tc_stats[RTNL_TC_OVERLIMITS],
            g->tc_stats[RTNL_TC_QLEN],
            g->tc_stats[RTNL_TC_BACKLOG]);

      res = nl_cancel_down_bytes(g->tc_stats[RTNL_TC_RATE_BPS], &unit);

      strcpy(fmt, "        %7.2f %s/s%9u pps");

      if (*unit == 'B')
            fmt[11] = '9';

      nl_dump_line(p, fmt, res, unit, g->tc_stats[RTNL_TC_RATE_PPS]);
}

int tca_compare(struct nl_object *_a, struct nl_object *_b,
            uint32_t attrs, int flags)
{
      struct rtnl_tca *a = (struct rtnl_tca *) _a;
      struct rtnl_tca *b = (struct rtnl_tca *) _b;
      int diff = 0;

#define TC_DIFF(ATTR, EXPR) ATTR_DIFF(attrs, TCA_ATTR_##ATTR, a, b, EXPR)

      diff |= TC_DIFF(HANDLE,       a->tc_handle != b->tc_handle);
      diff |= TC_DIFF(PARENT,       a->tc_parent != b->tc_parent);
      diff |= TC_DIFF(IFINDEX,      a->tc_ifindex != b->tc_ifindex);
      diff |= TC_DIFF(KIND,         strcmp(a->tc_kind, b->tc_kind));

#undef TC_DIFF

      return diff;
}

void tca_set_ifindex(struct rtnl_tca *t, int ifindex)
{
      t->tc_ifindex = ifindex;
      t->ce_mask |= TCA_ATTR_IFINDEX;
}

int tca_get_ifindex(struct rtnl_tca *t)
{
      return t->tc_ifindex;
}

void tca_set_handle(struct rtnl_tca *t, uint32_t handle)
{
      t->tc_handle = handle;
      t->ce_mask |= TCA_ATTR_HANDLE;
}

uint32_t tca_get_handle(struct rtnl_tca *t)
{
      if (t->ce_mask & TCA_ATTR_HANDLE)
            return t->tc_handle;
      else
            return 0;
}

void tca_set_parent(struct rtnl_tca *t, uint32_t parent)
{
      t->tc_parent = parent;
      t->ce_mask |= TCA_ATTR_PARENT;
}

uint32_t tca_get_parent(struct rtnl_tca *t)
{
      if (t->ce_mask & TCA_ATTR_PARENT)
            return t->tc_parent;
      else
            return 0;
}

void tca_set_kind(struct rtnl_tca *t, const char *kind)
{
      strncpy(t->tc_kind, kind, sizeof(t->tc_kind) - 1);
      t->ce_mask |= TCA_ATTR_KIND;
}

char *tca_get_kind(struct rtnl_tca *t)
{
      if (t->ce_mask & TCA_ATTR_KIND)
            return t->tc_kind;
      else
            return NULL;
}

uint64_t tca_get_stat(struct rtnl_tca *t, int id)
{
      if (id < 0 || id > RTNL_TC_STATS_MAX)
            return 0;

      return t->tc_stats[id];
}

int tca_build_msg(struct rtnl_tca *tca, int type, int flags,
              struct nl_msg **result)
{
      struct nl_msg *msg;
      struct tcmsg tchdr = {
            .tcm_family = AF_UNSPEC,
            .tcm_ifindex = tca->tc_ifindex,
            .tcm_handle = tca->tc_handle,
            .tcm_parent = tca->tc_parent,
      };

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

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

      if (tca->ce_mask & TCA_ATTR_KIND)
          NLA_PUT_STRING(msg, TCA_KIND, tca->tc_kind);

      *result = msg;
      return 0;

nla_put_failure:
      nlmsg_free(msg);
      return -NLE_MSGSIZE;
}

/** @endcond */

/**
 * @name Utilities
 * @{
 */

/**
 * Calculate time required to transmit buffer at a specific rate
 * @arg bufsize         Size of buffer to be transmited in bytes.
 * @arg rate            Transmit rate in bytes per second.
 *
 * Calculates the number of micro seconds required to transmit a
 * specific buffer at a specific transmit rate.
 *
 * @f[
 *   txtime=\frac{bufsize}{rate}10^6
 * @f]
 * 
 * @return Required transmit time in micro seconds.
 */
00375 int rtnl_tc_calc_txtime(int bufsize, int rate)
{
      double tx_time_secs;
      
      tx_time_secs = (double) bufsize / (double) rate;

      return tx_time_secs * 1000000.;
}

/**
 * Calculate buffer size able to transmit in a specific time and rate.
 * @arg txtime          Available transmit time in micro seconds.
 * @arg rate            Transmit rate in bytes per second.
 *
 * Calculates the size of the buffer that can be transmitted in a
 * specific time period at a specific transmit rate.
 *
 * @f[
 *   bufsize=\frac{{txtime} \times {rate}}{10^6}
 * @f]
 *
 * @return Size of buffer in bytes.
 */
00398 int rtnl_tc_calc_bufsize(int txtime, int rate)
{
      double bufsize;

      bufsize = (double) txtime * (double) rate;

      return bufsize / 1000000.;
}

/**
 * Calculate the binary logarithm for a specific cell size
 * @arg cell_size Size of cell, must be a power of two.
 * @return Binary logirhtm of cell size or a negative error code.
 */
00412 int rtnl_tc_calc_cell_log(int cell_size)
{
      int i;

      for (i = 0; i < 32; i++)
            if ((1 << i) == cell_size)
                  return i;

      return -NLE_INVAL;
}


/** @} */

/**
 * @name Rate Tables
 * @{
 */

/**
 * Compute a transmission time lookup table
 * @arg dst  Destination buffer of RTNL_TC_RTABLE_SIZE uint32_t[].
 * @arg mpu  Minimal size of a packet at all times.
 * @arg overhead Overhead to be added to each packet.
 * @arg cell       Size of cell, i.e. size of step between entries in bytes.
 * @arg rate       Rate in bytes per second.
 *
 * Computes a table of RTNL_TC_RTABLE_SIZE entries specyfing the
 * transmission times for various packet sizes, e.g. the transmission
 * time for a packet of size \c pktsize could be looked up:
 * @code
 * txtime = table[pktsize >> log2(cell)];
 * @endcode
 */
00446 int rtnl_tc_build_rate_table(uint32_t *dst, uint8_t mpu, uint8_t overhead,
                       int cell, int rate)
{
      int i, size, cell_log;

      cell_log = rtnl_tc_calc_cell_log(cell);
      if (cell_log < 0)
            return cell_log;

      for (i = 0; i < RTNL_TC_RTABLE_SIZE; i++) {
            size = (i << cell_log) + overhead;
            if (size < mpu)
                  size = mpu;

            dst[i] = rtnl_tc_calc_txtime(size, rate);
      }

      return 0;
}

/** @} */

/**
 * @name Traffic Control Handle Translations
 * @{
 */

/**
 * Convert a traffic control handle to a character string (Reentrant).
 * @arg handle          traffic control handle
 * @arg buf       destination buffer
 * @arg len       buffer length
 *
 * Converts a tarffic control handle to a character string in the
 * form of \c MAJ:MIN and stores it in the specified destination buffer.
 *
 * @return The destination buffer or the type encoded in hexidecimal
 *         form if no match was found.
 */
00485 char * rtnl_tc_handle2str(uint32_t handle, char *buf, size_t len)
{
      if (TC_H_ROOT == handle)
            snprintf(buf, len, "root");
      else if (TC_H_UNSPEC == handle)
            snprintf(buf, len, "none");
      else if (0 == TC_H_MAJ(handle))
            snprintf(buf, len, ":%02x", TC_H_MIN(handle));
      else if (0 == TC_H_MIN(handle))
            snprintf(buf, len, "%02x:", TC_H_MAJ(handle) >> 16);
      else
            snprintf(buf, len, "%02x:%02x",
                  TC_H_MAJ(handle) >> 16, TC_H_MIN(handle));

      return buf;
}

/**
 * Convert a charactering strint to a traffic control handle
 * @arg name            traffic control handle as character string
 * @arg res       destination buffer
 *
 * Converts the provided character string specifying a traffic
 * control handle to the corresponding numeric value.
 *
 * The handle must be provided in one of the following formats:
 *  - root
 *  - none
 *  - XXXX:
 *  - :YYYY
 *  - XXXX:YYYY
 *  - XXXXYYYY
 *
 * @return 0 on success or a negative error code
 */
00520 int rtnl_tc_str2handle(const char *name, uint32_t *res)
{
      char *colon, *end;
      uint32_t h;

      if (!strcasecmp(name, "root")) {
            *res = TC_H_ROOT;
            return 0;
      }

      if (!strcasecmp(name, "none")) {
            *res = TC_H_UNSPEC;
            return 0;
      }

      h = strtoul(name, &colon, 16);

      if (colon == name) {
            /* :YYYY */
            h = 0;
            if (':' != *colon)
                  return -NLE_INVAL;
      }

      if (':' == *colon) {
            /* check if we would lose bits */
            if (TC_H_MAJ(h))
                  return -NLE_RANGE;
            h <<= 16;

            if ('\0' == colon[1]) {
                  /* XXXX: */
                  *res = h;
            } else {
                  /* XXXX:YYYY */
                  uint32_t l = strtoul(colon+1, &end, 16);

                  /* check if we overlap with major part */
                  if (TC_H_MAJ(l))
                        return -NLE_RANGE;

                  if ('\0' != *end)
                        return -NLE_INVAL;

                  *res = (h | l);
            }
      } else if ('\0' == *colon) {
            /* XXXXYYYY */
            *res = h;
      } else
            return -NLE_INVAL;

      return 0;
}

/** @} */

/** @} */

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