net/batman-adv/aggregation.c

   1 /*
   2  * Copyright (C) 2007-2011 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 #include "hard-interface.h"
  27
  28 /* calculate the size of the tt information for a given packet */
  29 static int tt_len(struct batman_packet *batman_packet)
  30 {
  31         return batman_packet->num_tt * ETH_ALEN;
  32 }
  33
  34 /* return true if new_packet can be aggregated with forw_packet */
  35 static bool can_aggregate_with(struct batman_packet *new_batman_packet,
  36                                int packet_len,
  37                                unsigned long send_time,
  38                                bool directlink,
  39                                struct hard_iface *if_incoming,
  40                                struct forw_packet *forw_packet)
  41 {
  42         struct batman_packet *batman_packet =
  43                 (struct batman_packet *)forw_packet->skb->data;
  44         int aggregated_bytes = forw_packet->packet_len + packet_len;
  45
  46         /**
  47          * we can aggregate the current packet to this aggregated packet
  48          * if:
  49          *
  50          * - the send time is within our MAX_AGGREGATION_MS time
  51          * - the resulting packet wont be bigger than
  52          *   MAX_AGGREGATION_BYTES
  53          */
  54
  55         if (time_before(send_time, forw_packet->send_time) &&
  56             time_after_eq(send_time + msecs_to_jiffies(MAX_AGGREGATION_MS),
  57                                         forw_packet->send_time) &&
  58             (aggregated_bytes <= MAX_AGGREGATION_BYTES)) {
  59
  60                 /**
  61                  * check aggregation compatibility
  62                  * -> direct link packets are broadcasted on
  63                  *    their interface only
  64                  * -> aggregate packet if the current packet is
  65                  *    a "global" packet as well as the base
  66                  *    packet
  67                  */
  68
  69                 /* packets without direct link flag and high TTL
  70                  * are flooded through the net  */
  71                 if ((!directlink) &&
  72                     (!(batman_packet->flags & DIRECTLINK)) &&
  73                     (batman_packet->ttl != 1) &&
  74
  75                     /* own packets originating non-primary
  76                      * interfaces leave only that interface */
  77                     ((!forw_packet->own) ||
  78                      (forw_packet->if_incoming->if_num == 0)))
  79                         return true;
  80
  81                 /* if the incoming packet is sent via this one
  82                  * interface only - we still can aggregate */
  83                 if ((directlink) &&
  84                     (new_batman_packet->ttl == 1) &&
  85                     (forw_packet->if_incoming == if_incoming) &&
  86
  87                     /* packets from direct neighbors or
  88                      * own secondary interface packets
  89                      * (= secondary interface packets in general) */
  90                     (batman_packet->flags & DIRECTLINK ||
  91                      (forw_packet->own &&
  92                       forw_packet->if_incoming->if_num != 0)))
  93                         return true;
  94         }
  95
  96         return false;
  97 }
  98
  99 /* create a new aggregated packet and add this packet to it */
 100 static void new_aggregated_packet(unsigned char *packet_buff, int packet_len,
 101                                   unsigned long send_time, bool direct_link,
 102                                   struct hard_iface *if_incoming,
 103                                   int own_packet)
 104 {
 105         struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 106         struct forw_packet *forw_packet_aggr;
 107         unsigned char *skb_buff;
 108
 109         if (!atomic_inc_not_zero(&if_incoming->refcount))
 110                 return;
 111
 112         /* own packet should always be scheduled */
 113         if (!own_packet) {
 114                 if (!atomic_dec_not_zero(&bat_priv->batman_queue_left)) {
 115                         bat_dbg(DBG_BATMAN, bat_priv,
 116                                 "batman packet queue full\n");
 117                         goto out;
 118                 }
 119         }
 120
 121         forw_packet_aggr = kmalloc(sizeof(struct forw_packet), GFP_ATOMIC);
 122         if (!forw_packet_aggr) {
 123                 if (!own_packet)
 124                         atomic_inc(&bat_priv->batman_queue_left);
 125                 goto out;
 126         }
 127
 128         if ((atomic_read(&bat_priv->aggregated_ogms)) &&
 129             (packet_len < MAX_AGGREGATION_BYTES))
 130                 forw_packet_aggr->skb = dev_alloc_skb(MAX_AGGREGATION_BYTES +
 131                                                       sizeof(struct ethhdr));
 132         else
 133                 forw_packet_aggr->skb = dev_alloc_skb(packet_len +
 134                                                       sizeof(struct ethhdr));
 135
 136         if (!forw_packet_aggr->skb) {
 137                 if (!own_packet)
 138                         atomic_inc(&bat_priv->batman_queue_left);
 139                 kfree(forw_packet_aggr);
 140                 goto out;
 141         }
 142         skb_reserve(forw_packet_aggr->skb, sizeof(struct ethhdr));
 143
 144         INIT_HLIST_NODE(&forw_packet_aggr->list);
 145
 146         skb_buff = skb_put(forw_packet_aggr->skb, packet_len);
 147         forw_packet_aggr->packet_len = packet_len;
 148         memcpy(skb_buff, packet_buff, packet_len);
 149
 150         forw_packet_aggr->own = own_packet;
 151         forw_packet_aggr->if_incoming = if_incoming;
 152         forw_packet_aggr->num_packets = 0;
 153         forw_packet_aggr->direct_link_flags = 0;
 154         forw_packet_aggr->send_time = send_time;
 155
 156         /* save packet direct link flag status */
 157         if (direct_link)
 158                 forw_packet_aggr->direct_link_flags |= 1;
 159
 160         /* add new packet to packet list */
 161         spin_lock_bh(&bat_priv->forw_bat_list_lock);
 162         hlist_add_head(&forw_packet_aggr->list, &bat_priv->forw_bat_list);
 163         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 164
 165         /* start timer for this packet */
 166         INIT_DELAYED_WORK(&forw_packet_aggr->delayed_work,
 167                           send_outstanding_bat_packet);
 168         queue_delayed_work(bat_event_workqueue,
 169                            &forw_packet_aggr->delayed_work,
 170                            send_time - jiffies);
 171
 172         return;
 173 out:
 174         hardif_free_ref(if_incoming);
 175 }
 176
 177 /* aggregate a new packet into the existing aggregation */
 178 static void aggregate(struct forw_packet *forw_packet_aggr,
 179                       unsigned char *packet_buff,
 180                       int packet_len,
 181                       bool direct_link)
 182 {
 183         unsigned char *skb_buff;
 184
 185         skb_buff = skb_put(forw_packet_aggr->skb, packet_len);
 186         memcpy(skb_buff, packet_buff, packet_len);
 187         forw_packet_aggr->packet_len += packet_len;
 188         forw_packet_aggr->num_packets++;
 189
 190         /* save packet direct link flag status */
 191         if (direct_link)
 192                 forw_packet_aggr->direct_link_flags |=
 193                         (1 << forw_packet_aggr->num_packets);
 194 }
 195
 196 void add_bat_packet_to_list(struct bat_priv *bat_priv,
 197                             unsigned char *packet_buff, int packet_len,
 198                             struct hard_iface *if_incoming, char own_packet,
 199                             unsigned long send_time)
 200 {
 201         /**
 202          * _aggr -> pointer to the packet we want to aggregate with
 203          * _pos -> pointer to the position in the queue
 204          */
 205         struct forw_packet *forw_packet_aggr = NULL, *forw_packet_pos = NULL;
 206         struct hlist_node *tmp_node;
 207         struct batman_packet *batman_packet =
 208                 (struct batman_packet *)packet_buff;
 209         bool direct_link = batman_packet->flags & DIRECTLINK ? 1 : 0;
 210
 211         /* find position for the packet in the forward queue */
 212         spin_lock_bh(&bat_priv->forw_bat_list_lock);
 213         /* own packets are not to be aggregated */
 214         if ((atomic_read(&bat_priv->aggregated_ogms)) && (!own_packet)) {
 215                 hlist_for_each_entry(forw_packet_pos, tmp_node,
 216                                      &bat_priv->forw_bat_list, list) {
 217                         if (can_aggregate_with(batman_packet,
 218                                                packet_len,
 219                                                send_time,
 220                                                direct_link,
 221                                                if_incoming,
 222                                                forw_packet_pos)) {
 223                                 forw_packet_aggr = forw_packet_pos;
 224                                 break;
 225                         }
 226                 }
 227         }
 228
 229         /* nothing to aggregate with - either aggregation disabled or no
 230          * suitable aggregation packet found */
 231         if (!forw_packet_aggr) {
 232                 /* the following section can run without the lock */
 233                 spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 234
 235                 /**
 236                  * if we could not aggregate this packet with one of the others
 237                  * we hold it back for a while, so that it might be aggregated
 238                  * later on
 239                  */
 240                 if ((!own_packet) &&
 241                     (atomic_read(&bat_priv->aggregated_ogms)))
 242                         send_time += msecs_to_jiffies(MAX_AGGREGATION_MS);
 243
 244                 new_aggregated_packet(packet_buff, packet_len,
 245                                       send_time, direct_link,
 246                                       if_incoming, own_packet);
 247         } else {
 248                 aggregate(forw_packet_aggr,
 249                           packet_buff, packet_len,
 250                           direct_link);
 251                 spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 252         }
 253 }
 254
 255 /* unpack the aggregated packets and process them one by one */
 256 void receive_aggr_bat_packet(struct ethhdr *ethhdr, unsigned char *packet_buff,
 257                              int packet_len, struct hard_iface *if_incoming)
 258 {
 259         struct batman_packet *batman_packet;
 260         int buff_pos = 0;
 261         unsigned char *tt_buff;
 262
 263         batman_packet = (struct batman_packet *)packet_buff;
 264
 265         do {
 266                 /* network to host order for our 32bit seqno, and the
 267                    orig_interval. */
 268                 batman_packet->seqno = ntohl(batman_packet->seqno);
 269
 270                 tt_buff = packet_buff + buff_pos + BAT_PACKET_LEN;
 271                 receive_bat_packet(ethhdr, batman_packet,
 272                                    tt_buff, tt_len(batman_packet),
 273                                    if_incoming);
 274
 275                 buff_pos += BAT_PACKET_LEN + tt_len(batman_packet);
 276                 batman_packet = (struct batman_packet *)
 277                         (packet_buff + buff_pos);
 278         } while (aggregated_packet(buff_pos, packet_len,
 279                                    batman_packet->num_tt));
 280 }