drivers/staging/batman-adv/aggregation.c

   1 /*
   2  * Copyright (C) 2007-2010 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             time_after_eq(send_time + msecs_to_jiffies(MAX_AGGREGATION_MS),
  56                                         forw_packet->send_time) &&
  57             (aggregated_bytes <= MAX_AGGREGATION_BYTES)) {
  58
  59                 /**
  60                  * check aggregation compatibility
  61                  * -> direct link packets are broadcasted on
  62                  *    their interface only
  63                  * -> aggregate packet if the current packet is
  64                  *    a "global" packet as well as the base
  65                  *    packet
  66                  */
  67
  68                 /* packets without direct link flag and high TTL
  69                  * are flooded through the net  */
  70                 if ((!directlink) &&
  71                     (!(batman_packet->flags & DIRECTLINK)) &&
  72                     (batman_packet->ttl != 1) &&
  73
  74                     /* own packets originating non-primary
  75                      * interfaces leave only that interface */
  76                     ((!forw_packet->own) ||
  77                      (forw_packet->if_incoming->if_num == 0)))
  78                         return true;
  79
  80                 /* if the incoming packet is sent via this one
  81                  * interface only - we still can aggregate */
  82                 if ((directlink) &&
  83                     (new_batman_packet->ttl == 1) &&
  84                     (forw_packet->if_incoming == if_incoming) &&
  85
  86                     /* packets from direct neighbors or
  87                      * own secondary interface packets
  88                      * (= secondary interface packets in general) */
  89                     (batman_packet->flags & DIRECTLINK ||
  90                      (forw_packet->own &&
  91                       forw_packet->if_incoming->if_num != 0)))
  92                         return true;
  93         }
  94
  95         return false;
  96 }
  97
  98 #define atomic_dec_not_zero(v)          atomic_add_unless((v), -1, 0)
  99 /* create a new aggregated packet and add this packet to it */
 100 static void new_aggregated_packet(unsigned char *packet_buff,
 101                            int packet_len,
 102                            unsigned long send_time,
 103                            bool direct_link,
 104                            struct batman_if *if_incoming,
 105                            int own_packet)
 106 {
 107         struct forw_packet *forw_packet_aggr;
 108         unsigned long flags;
 109
 110         /* own packet should always be scheduled */
 111         if (!own_packet) {
 112                 if (!atomic_dec_not_zero(&batman_queue_left)) {
 113                         bat_dbg(DBG_BATMAN, "batman packet queue full\n");
 114                         return;
 115                 }
 116         }
 117
 118         forw_packet_aggr = kmalloc(sizeof(struct forw_packet), GFP_ATOMIC);
 119         if (!forw_packet_aggr) {
 120                 if (!own_packet)
 121                         atomic_inc(&batman_queue_left);
 122                 return;
 123         }
 124
 125         forw_packet_aggr->packet_buff = kmalloc(MAX_AGGREGATION_BYTES,
 126                                                 GFP_ATOMIC);
 127         if (!forw_packet_aggr->packet_buff) {
 128                 if (!own_packet)
 129                         atomic_inc(&batman_queue_left);
 130                 kfree(forw_packet_aggr);
 131                 return;
 132         }
 133
 134         INIT_HLIST_NODE(&forw_packet_aggr->list);
 135
 136         forw_packet_aggr->packet_len = packet_len;
 137         memcpy(forw_packet_aggr->packet_buff,
 138                packet_buff,
 139                forw_packet_aggr->packet_len);
 140
 141         forw_packet_aggr->skb = NULL;
 142         forw_packet_aggr->own = own_packet;
 143         forw_packet_aggr->if_incoming = if_incoming;
 144         forw_packet_aggr->num_packets = 0;
 145         forw_packet_aggr->direct_link_flags = 0;
 146         forw_packet_aggr->send_time = send_time;
 147
 148         /* save packet direct link flag status */
 149         if (direct_link)
 150                 forw_packet_aggr->direct_link_flags |= 1;
 151
 152         /* add new packet to packet list */
 153         spin_lock_irqsave(&forw_bat_list_lock, flags);
 154         hlist_add_head(&forw_packet_aggr->list, &forw_bat_list);
 155         spin_unlock_irqrestore(&forw_bat_list_lock, flags);
 156
 157         /* start timer for this packet */
 158         INIT_DELAYED_WORK(&forw_packet_aggr->delayed_work,
 159                           send_outstanding_bat_packet);
 160         queue_delayed_work(bat_event_workqueue,
 161                            &forw_packet_aggr->delayed_work,
 162                            send_time - jiffies);
 163 }
 164
 165 /* aggregate a new packet into the existing aggregation */
 166 static void aggregate(struct forw_packet *forw_packet_aggr,
 167                       unsigned char *packet_buff,
 168                       int packet_len,
 169                       bool direct_link)
 170 {
 171         memcpy((forw_packet_aggr->packet_buff + forw_packet_aggr->packet_len),
 172                packet_buff, packet_len);
 173         forw_packet_aggr->packet_len += packet_len;
 174         forw_packet_aggr->num_packets++;
 175
 176         /* save packet direct link flag status */
 177         if (direct_link)
 178                 forw_packet_aggr->direct_link_flags |=
 179                         (1 << forw_packet_aggr->num_packets);
 180 }
 181
 182 void add_bat_packet_to_list(struct bat_priv *bat_priv,
 183                             unsigned char *packet_buff, int packet_len,
 184                             struct batman_if *if_incoming, char own_packet,
 185                             unsigned long send_time)
 186 {
 187         /**
 188          * _aggr -> pointer to the packet we want to aggregate with
 189          * _pos -> pointer to the position in the queue
 190          */
 191         struct forw_packet *forw_packet_aggr = NULL, *forw_packet_pos = NULL;
 192         struct hlist_node *tmp_node;
 193         struct batman_packet *batman_packet =
 194                 (struct batman_packet *)packet_buff;
 195         bool direct_link = batman_packet->flags & DIRECTLINK ? 1 : 0;
 196         unsigned long flags;
 197
 198         /* find position for the packet in the forward queue */
 199         spin_lock_irqsave(&forw_bat_list_lock, flags);
 200         /* own packets are not to be aggregated */
 201         if ((atomic_read(&bat_priv->aggregation_enabled)) && (!own_packet)) {
 202                 hlist_for_each_entry(forw_packet_pos, tmp_node, &forw_bat_list,
 203                                      list) {
 204                         if (can_aggregate_with(batman_packet,
 205                                                packet_len,
 206                                                send_time,
 207                                                direct_link,
 208                                                if_incoming,
 209                                                forw_packet_pos)) {
 210                                 forw_packet_aggr = forw_packet_pos;
 211                                 break;
 212                         }
 213                 }
 214         }
 215
 216         /* nothing to aggregate with - either aggregation disabled or no
 217          * suitable aggregation packet found */
 218         if (forw_packet_aggr == NULL) {
 219                 /* the following section can run without the lock */
 220                 spin_unlock_irqrestore(&forw_bat_list_lock, flags);
 221
 222                 /**
 223                  * if we could not aggregate this packet with one of the others
 224                  * we hold it back for a while, so that it might be aggregated
 225                  * later on
 226                  */
 227                 if ((!own_packet) &&
 228                     (atomic_read(&bat_priv->aggregation_enabled)))
 229                         send_time += msecs_to_jiffies(MAX_AGGREGATION_MS);
 230
 231                 new_aggregated_packet(packet_buff, packet_len,
 232                                       send_time, direct_link,
 233                                       if_incoming, own_packet);
 234         } else {
 235                 aggregate(forw_packet_aggr,
 236                           packet_buff, packet_len,
 237                           direct_link);
 238                 spin_unlock_irqrestore(&forw_bat_list_lock, flags);
 239         }
 240 }
 241
 242 /* unpack the aggregated packets and process them one by one */
 243 void receive_aggr_bat_packet(struct ethhdr *ethhdr, unsigned char *packet_buff,
 244                              int packet_len, struct batman_if *if_incoming)
 245 {
 246         struct batman_packet *batman_packet;
 247         int buff_pos = 0;
 248         unsigned char *hna_buff;
 249
 250         batman_packet = (struct batman_packet *)packet_buff;
 251
 252         while (aggregated_packet(buff_pos, packet_len,
 253                                  batman_packet->num_hna)) {
 254
 255                 /* network to host order for our 16bit seqno, and the
 256                    orig_interval. */
 257                 batman_packet->seqno = ntohs(batman_packet->seqno);
 258
 259                 hna_buff = packet_buff + buff_pos + BAT_PACKET_LEN;
 260                 receive_bat_packet(ethhdr, batman_packet,
 261                                    hna_buff, hna_len(batman_packet),
 262                                    if_incoming);
 263
 264                 buff_pos += BAT_PACKET_LEN + hna_len(batman_packet);
 265                 batman_packet = (struct batman_packet *)
 266                         (packet_buff + buff_pos);
 267         }
 268 }