drivers/staging/batman-adv/aggregation.c

   1 /*
   2  * Copyright (C) 2007-2009 B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner, Simon Wunderlich
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA
  19  *
  20  */
  21
  22 #include "main.h"
  23 #include "aggregation.h"
  24 #include "send.h"
  25 #include "routing.h"
  26
  27 /* calculate the size of the hna information for a given packet */
  28 static int hna_len(struct batman_packet *batman_packet)
  29 {
  30         return batman_packet->num_hna * ETH_ALEN;
  31 }
  32
  33 /* return true if new_packet can be aggregated with forw_packet */
  34 static bool can_aggregate_with(struct batman_packet *new_batman_packet,
  35                                int packet_len,
  36                                unsigned long send_time,
  37                                bool directlink,
  38                                struct batman_if *if_incoming,
  39                                struct forw_packet *forw_packet)
  40 {
  41         struct batman_packet *batman_packet =
  42                 (struct batman_packet *)forw_packet->packet_buff;
  43         int aggregated_bytes = forw_packet->packet_len + packet_len;
  44
  45         /**
  46          * we can aggregate the current packet to this aggregated packet
  47          * if:
  48          *
  49          * - the send time is within our MAX_AGGREGATION_MS time
  50          * - the resulting packet wont be bigger than
  51          *   MAX_AGGREGATION_BYTES
  52          */
  53
  54         if (time_before(send_time, forw_packet->send_time) &&
  55             (aggregated_bytes <= MAX_AGGREGATION_BYTES)) {
  56
  57                 /**
  58                  * check aggregation compatibility
  59                  * -> direct link packets are broadcasted on
  60                  *    their interface only
  61                  * -> aggregate packet if the current packet is
  62                  *    a "global" packet as well as the base
  63                  *    packet
  64                  */
  65
  66                 /* packets without direct link flag and high TTL
  67                  * are flooded through the net  */
  68                 if ((!directlink) &&
  69                     (!(batman_packet->flags & DIRECTLINK)) &&
  70                     (batman_packet->ttl != 1) &&
  71
  72                     /* own packets originating non-primary
  73                      * interfaces leave only that interface */
  74                     ((!forw_packet->own) ||
  75                      (forw_packet->if_incoming->if_num == 0)))
  76                         return true;
  77
  78                 /* if the incoming packet is sent via this one
  79                  * interface only - we still can aggregate */
  80                 if ((directlink) &&
  81                     (new_batman_packet->ttl == 1) &&
  82                     (forw_packet->if_incoming == if_incoming))
  83                         return true;
  84
  85         }
  86
  87         return false;
  88 }
  89
  90 /* create a new aggregated packet and add this packet to it */
  91 static void new_aggregated_packet(unsigned char *packet_buff,
  92                            int packet_len,
  93                            unsigned long send_time,
  94                            bool direct_link,
  95                            struct batman_if *if_incoming,
  96                            int own_packet)
  97 {
  98         struct forw_packet *forw_packet_aggr;
  99
 100         forw_packet_aggr = kmalloc(sizeof(struct forw_packet), GFP_ATOMIC);
 101         if (!forw_packet_aggr)
 102                 return;
 103
 104         forw_packet_aggr->packet_buff = kmalloc(MAX_AGGREGATION_BYTES,
 105                                                 GFP_ATOMIC);
 106         if (!forw_packet_aggr->packet_buff) {
 107                 kfree(forw_packet_aggr);
 108                 return;
 109         }
 110
 111         INIT_HLIST_NODE(&forw_packet_aggr->list);
 112
 113         forw_packet_aggr->packet_len = packet_len;
 114         memcpy(forw_packet_aggr->packet_buff,
 115                packet_buff,
 116                forw_packet_aggr->packet_len);
 117
 118         forw_packet_aggr->own = own_packet;
 119         forw_packet_aggr->if_incoming = if_incoming;
 120         forw_packet_aggr->num_packets = 0;
 121         forw_packet_aggr->direct_link_flags = 0;
 122         forw_packet_aggr->send_time = send_time;
 123
 124         /* save packet direct link flag status */
 125         if (direct_link)
 126                 forw_packet_aggr->direct_link_flags |= 1;
 127
 128         /* add new packet to packet list */
 129         spin_lock(&forw_bat_list_lock);
 130         hlist_add_head(&forw_packet_aggr->list, &forw_bat_list);
 131         spin_unlock(&forw_bat_list_lock);
 132
 133         /* start timer for this packet */
 134         INIT_DELAYED_WORK(&forw_packet_aggr->delayed_work,
 135                           send_outstanding_bat_packet);
 136         queue_delayed_work(bat_event_workqueue,
 137                            &forw_packet_aggr->delayed_work,
 138                            send_time - jiffies);
 139 }
 140
 141 /* aggregate a new packet into the existing aggregation */
 142 static void aggregate(struct forw_packet *forw_packet_aggr,
 143                       unsigned char *packet_buff,
 144                       int packet_len,
 145                       bool direct_link)
 146 {
 147         memcpy((forw_packet_aggr->packet_buff + forw_packet_aggr->packet_len),
 148                packet_buff, packet_len);
 149         forw_packet_aggr->packet_len += packet_len;
 150         forw_packet_aggr->num_packets++;
 151
 152         /* save packet direct link flag status */
 153         if (direct_link)
 154                 forw_packet_aggr->direct_link_flags |=
 155                         (1 << forw_packet_aggr->num_packets);
 156 }
 157
 158 void add_bat_packet_to_list(unsigned char *packet_buff, int packet_len,
 159                             struct batman_if *if_incoming, char own_packet,
 160                             unsigned long send_time)
 161 {
 162         /**
 163          * _aggr -> pointer to the packet we want to aggregate with
 164          * _pos -> pointer to the position in the queue
 165          */
 166         struct forw_packet *forw_packet_aggr = NULL, *forw_packet_pos = NULL;
 167         struct hlist_node *tmp_node;
 168         struct batman_packet *batman_packet =
 169                 (struct batman_packet *)packet_buff;
 170         bool direct_link = batman_packet->flags & DIRECTLINK ? 1 : 0;
 171
 172         /* find position for the packet in the forward queue */
 173         spin_lock(&forw_bat_list_lock);
 174         /* own packets are not to be aggregated */
 175         if ((atomic_read(&aggregation_enabled)) && (!own_packet)) {
 176                 hlist_for_each_entry(forw_packet_pos, tmp_node, &forw_bat_list,
 177                                      list) {
 178                         if (can_aggregate_with(batman_packet,
 179                                                packet_len,
 180                                                send_time,
 181                                                direct_link,
 182                                                if_incoming,
 183                                                forw_packet_pos)) {
 184                                 forw_packet_aggr = forw_packet_pos;
 185                                 break;
 186                         }
 187                 }
 188         }
 189
 190         /* nothing to aggregate with - either aggregation disabled or no
 191          * suitable aggregation packet found */
 192         if (forw_packet_aggr == NULL) {
 193                 /* the following section can run without the lock */
 194                 spin_unlock(&forw_bat_list_lock);
 195                 new_aggregated_packet(packet_buff, packet_len,
 196                                       send_time, direct_link,
 197                                       if_incoming, own_packet);
 198         } else {
 199                 aggregate(forw_packet_aggr,
 200                           packet_buff, packet_len,
 201                           direct_link);
 202                 spin_unlock(&forw_bat_list_lock);
 203         }
 204 }
 205
 206 /* unpack the aggregated packets and process them one by one */
 207 void receive_aggr_bat_packet(struct ethhdr *ethhdr, unsigned char *packet_buff,
 208                              int packet_len, struct batman_if *if_incoming)
 209 {
 210         struct batman_packet *batman_packet;
 211         int buff_pos = 0;
 212         unsigned char *hna_buff;
 213
 214         batman_packet = (struct batman_packet *)packet_buff;
 215
 216         while (aggregated_packet(buff_pos, packet_len,
 217                                  batman_packet->num_hna)) {
 218
 219                 /* network to host order for our 16bit seqno, and the
 220                    orig_interval. */
 221                 batman_packet->seqno = ntohs(batman_packet->seqno);
 222
 223                 hna_buff = packet_buff + buff_pos + BAT_PACKET_LEN;
 224                 receive_bat_packet(ethhdr, batman_packet,
 225                                    hna_buff, hna_len(batman_packet),
 226                                    if_incoming);
 227
 228                 buff_pos += BAT_PACKET_LEN + hna_len(batman_packet);
 229                 batman_packet = (struct batman_packet *)
 230                         (packet_buff + buff_pos);
 231         }
 232 }