sys/netproto/802_11/wlan/ieee80211_ageq.c

   1 /*-
   2  * Copyright (c) 2009 Sam Leffler, Errno Consulting
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include <sys/cdefs.h>
  27 __FBSDID("$FreeBSD$");
  28
  29 /*
  30  * IEEE 802.11 age queue support.
  31  */
  32 #include "opt_wlan.h"
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/kernel.h>
  37 #include <sys/malloc.h>
  38
  39 #include <sys/socket.h>
  40
  41 #include <net/if.h>
  42 #include <net/if_var.h>
  43 #include <net/if_media.h>
  44 #include <net/ethernet.h>
  45
  46 #include <netproto/802_11/ieee80211_var.h>
  47
  48 /*
  49  * Initialize an ageq.
  50  */
  51 void
  52 ieee80211_ageq_init(struct ieee80211_ageq *aq, int maxlen, const char *name)
  53 {
  54         memset(aq, 0, sizeof(*aq));
  55         aq->aq_maxlen = maxlen;
  56         IEEE80211_AGEQ_INIT(aq, name);          /* OS-dependent setup */
  57 }
  58
  59 /*
  60  * Cleanup an ageq initialized with ieee80211_ageq_init.  Note
  61  * the queue is assumed empty; this can be done with ieee80211_ageq_drain.
  62  */
  63 void
  64 ieee80211_ageq_cleanup(struct ieee80211_ageq *aq)
  65 {
  66         KASSERT(aq->aq_len == 0, ("%d frames on ageq", aq->aq_len));
  67         IEEE80211_AGEQ_DESTROY(aq);             /* OS-dependent cleanup */
  68 }
  69
  70 /*
  71  * Free an mbuf according to ageq rules: if marked as holding
  72  * and 802.11 frame then also reclaim a node reference from
  73  * the packet header; this handles packets q'd in the tx path.
  74  */
  75 static void
  76 ageq_mfree(struct mbuf *m)
  77 {
  78         if (m->m_flags & M_ENCAP) {
  79                 struct ieee80211_node *ni = (void *) m->m_pkthdr.rcvif;
  80                 ieee80211_free_node(ni);
  81         }
  82         m->m_nextpkt = NULL;
  83         m_freem(m);
  84 }
  85
  86 /*
  87  * Free a list of mbufs using ageq rules (see above).
  88  */
  89 void
  90 ieee80211_ageq_mfree(struct mbuf *m)
  91 {
  92         struct mbuf *next;
  93
  94         for (; m != NULL; m = next) {
  95                 next = m->m_nextpkt;
  96                 ageq_mfree(m);
  97         }
  98 }
  99
 100 /*
 101  * Append an mbuf to the ageq and mark it with the specified max age
 102  * If the frame is not removed before the age (in seconds) expires
 103  * then it is reclaimed (along with any node reference).
 104  */
 105 int
 106 ieee80211_ageq_append(struct ieee80211_ageq *aq, struct mbuf *m, int age)
 107 {
 108         IEEE80211_AGEQ_LOCK(aq);
 109         if (__predict_true(aq->aq_len < aq->aq_maxlen)) {
 110                 if (aq->aq_tail == NULL) {
 111                         aq->aq_head = m;
 112                 } else {
 113                         aq->aq_tail->m_nextpkt = m;
 114                         age -= M_AGE_GET(aq->aq_head);
 115                 }
 116                 KASSERT(age >= 0, ("age %d", age));
 117                 M_AGE_SET(m, age);
 118                 m->m_nextpkt = NULL;
 119                 aq->aq_tail = m;
 120                 aq->aq_len++;
 121                 IEEE80211_AGEQ_UNLOCK(aq);
 122                 return 0;
 123         } else {
 124                 /*
 125                  * No space, drop and cleanup references.
 126                  */
 127                 aq->aq_drops++;
 128                 IEEE80211_AGEQ_UNLOCK(aq);
 129                 /* XXX tail drop? */
 130                 ageq_mfree(m);
 131                 return ENOSPC;
 132         }
 133 }
 134
 135 /*
 136  * Drain/reclaim all frames from an ageq.
 137  */
 138 void
 139 ieee80211_ageq_drain(struct ieee80211_ageq *aq)
 140 {
 141         ieee80211_ageq_mfree(ieee80211_ageq_remove(aq, NULL));
 142 }
 143
 144 /*
 145  * Drain/reclaim frames associated with a specific node from an ageq.
 146  */
 147 void
 148 ieee80211_ageq_drain_node(struct ieee80211_ageq *aq,
 149         struct ieee80211_node *ni)
 150 {
 151         ieee80211_ageq_mfree(ieee80211_ageq_remove(aq, ni));
 152 }
 153
 154 /*
 155  * Age frames on the age queue.  Ages are stored as time
 156  * deltas (in seconds) relative to the head so we can check
 157  * and/or adjust only the head of the list.  If a frame's age
 158  * exceeds the time quanta then remove it.  The list of removed
 159  * frames is returned to the caller joined by m_nextpkt.
 160  */
 161 struct mbuf *
 162 ieee80211_ageq_age(struct ieee80211_ageq *aq, int quanta)
 163 {
 164         struct mbuf *head, **phead;
 165         struct mbuf *m;
 166
 167         phead = &head;
 168         if (aq->aq_len != 0) {
 169                 IEEE80211_AGEQ_LOCK(aq);
 170                 while ((m = aq->aq_head) != NULL && M_AGE_GET(m) < quanta) {
 171                         if ((aq->aq_head = m->m_nextpkt) == NULL)
 172                                 aq->aq_tail = NULL;
 173                         KASSERT(aq->aq_len > 0, ("aq len %d", aq->aq_len));
 174                         aq->aq_len--;
 175                         /* add to private list for return */
 176                         *phead = m;
 177                         phead = &m->m_nextpkt;
 178                 }
 179                 if (m != NULL)
 180                         M_AGE_SUB(m, quanta);
 181                 IEEE80211_AGEQ_UNLOCK(aq);
 182         }
 183         *phead = NULL;
 184         return head;
 185 }
 186
 187 /*
 188  * Remove all frames matching the specified node identifier
 189  * (NULL matches all).  Frames are returned as a list joined
 190  * by m_nextpkt.
 191  */
 192 struct mbuf *
 193 ieee80211_ageq_remove(struct ieee80211_ageq *aq,
 194         struct ieee80211_node *match)
 195 {
 196         struct mbuf *m, **prev, *ohead;
 197         struct mbuf *head, **phead;
 198
 199         IEEE80211_AGEQ_LOCK(aq);
 200         ohead = aq->aq_head;
 201         prev = &aq->aq_head;
 202         phead = &head;
 203         while ((m = *prev) != NULL) {
 204                 if (match != NULL && m->m_pkthdr.rcvif != (void *) match) {
 205                         prev = &m->m_nextpkt;
 206                         continue;
 207                 }
 208                 /*
 209                  * Adjust q length.
 210                  */
 211                 KASSERT(aq->aq_len > 0, ("aq len %d", aq->aq_len));
 212                 aq->aq_len--;
 213                 /*
 214                  * Remove from forward list; tail pointer is harder.
 215                  */
 216                 if (aq->aq_tail == m) {
 217                         KASSERT(m->m_nextpkt == NULL, ("not last"));
 218                         if (aq->aq_head == m) {         /* list empty */
 219                                 KASSERT(aq->aq_len == 0,
 220                                     ("not empty, len %d", aq->aq_len));
 221                                 aq->aq_tail = NULL;
 222                         } else {                        /* must be one before */
 223                                 aq->aq_tail = (struct mbuf *)((uintptr_t)prev -
 224                                     offsetof(struct mbuf, m_nextpkt));
 225                         }
 226                 }
 227                 *prev = m->m_nextpkt;
 228
 229                 /* add to private list for return */
 230                 *phead = m;
 231                 phead = &m->m_nextpkt;
 232         }
 233         if (head == ohead && aq->aq_head != NULL)       /* correct age */
 234                 M_AGE_SET(aq->aq_head, M_AGE_GET(head));
 235         IEEE80211_AGEQ_UNLOCK(aq);
 236
 237         *phead = NULL;
 238         return head;
 239 }