net/cor/rcv.c

   1 /*
   2  *      Connection oriented routing
   3  *      Copyright (C) 2007-2008 Michael Blizek
   4  *
   5  *      This program is free software; you can redistribute it and/or
   6  *      modify it under the terms of the GNU General Public License
   7  *      as published by the Free Software Foundation; either version 2
   8  *      of the License, or (at your option) any later version.
   9  *
  10  *      This program is distributed in the hope that it will be useful,
  11  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *      GNU 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 #ifndef _KERNEL_
  22         #define _KERNEL_
  23 #endif
  24
  25 #ifndef MODULE
  26         #define MODULE
  27 #endif
  28
  29 #include <linux/module.h>
  30 #include <linux/version.h>
  31 #include <linux/kernel.h>
  32 #include <linux/init.h>
  33 #include <linux/in.h>
  34
  35
  36 #include "cor.h"
  37
  38 atomic_t packets_in_workqueue = ATOMIC_INIT(0);
  39
  40 atomic_t ooo_packets = ATOMIC_INIT(0);
  41
  42 static struct workqueue_struct *packet_wq;
  43
  44 void drain_ooo_queue(struct conn *rconn)
  45 {
  46         struct sk_buff *skb;
  47
  48         BUG_ON(SOURCE_IN != rconn->sourcetype);
  49
  50         skb = rconn->source.in.reorder_queue.next;
  51
  52         while ((void *) skb != (void *) &(rconn->source.in.reorder_queue)) {
  53                 struct skb_procstate *ps = skb_pstate(skb);
  54                 int drop;
  55
  56                 BUG_ON(rconn != ps->rconn);
  57
  58                 if (rconn->source.in.next_seqno != ps->funcstate.rcv2.seqno)
  59                         break;
  60
  61                 drop = receive_skb(rconn, skb);
  62                 if (drop)
  63                         break;
  64
  65                 skb_unlink(skb, &(rconn->source.in.reorder_queue));
  66                 rconn->source.in.ooo_packets--;
  67                 atomic_dec(&(rconn->source.in.nb->ooo_packets));
  68                 atomic_dec(&ooo_packets);
  69
  70                 rconn->source.in.next_seqno += skb->len;
  71
  72         }
  73 }
  74
  75 static int _conn_rcv_ooo(struct sk_buff *skb)
  76 {
  77         struct skb_procstate *ps = skb_pstate(skb);
  78         struct conn *rconn = ps->rconn;
  79         struct sk_buff_head *reorder_queue = &(rconn->source.in.reorder_queue);
  80         struct sk_buff *curr = reorder_queue->next;
  81
  82         long ooo;
  83
  84         rconn->source.in.ooo_packets++;
  85         if (rconn->source.in.ooo_packets > MAX_TOTAL_OOO_PER_CONN)
  86                 goto drop_ooo3;
  87
  88         ooo = atomic_inc_return(&(rconn->source.in.nb->ooo_packets));
  89         if (ooo > MAX_TOTAL_OOO_PER_NEIGH)
  90                 goto drop_ooo2;
  91
  92         ooo = atomic_inc_return(&ooo_packets);
  93         if (ooo > MAX_TOTAL_OOO_PACKETS)
  94                 goto drop_ooo1;
  95
  96
  97         while (1) {
  98                 struct skb_procstate *ps2 = skb_pstate(curr);
  99
 100                 if ((void *) curr != (void *) reorder_queue) {
 101                         skb_queue_tail(reorder_queue, skb);
 102                         break;
 103                 }
 104
 105                 BUG_ON(rconn != ps2->rconn);
 106
 107                 if (ps->funcstate.rcv2.seqno > ps2->funcstate.rcv2.seqno) {
 108                         skb_insert(curr, skb, reorder_queue);
 109                         break;
 110                 }
 111         }
 112
 113         if (0) {
 114 drop_ooo1:
 115                 atomic_dec(&ooo_packets);
 116 drop_ooo2:
 117                 atomic_dec(&(rconn->source.in.nb->ooo_packets));
 118 drop_ooo3:
 119                 rconn->source.in.ooo_packets--;
 120
 121                 return 1;
 122         }
 123
 124         return 0;
 125 }
 126
 127 static void _conn_rcv(struct sk_buff *skb)
 128 {
 129         struct skb_procstate *ps = skb_pstate(skb);
 130         struct conn *rconn = ps->rconn;
 131         struct control_msg_out *cm = alloc_control_msg();
 132
 133         int in_order;
 134         int drop = 1;
 135
 136         BUG_ON(rconn->sourcetype != SOURCE_IN);
 137
 138         if (unlikely(cm == 0)) {
 139                 kfree_skb(skb);
 140                 goto out;
 141         }
 142
 143         mutex_lock(&(rconn->rcv_lock));
 144
 145         in_order = rconn->source.in.next_seqno != ps->funcstate.rcv2.seqno;
 146
 147         if (in_order == 0) {
 148                 drop = _conn_rcv_ooo(skb);
 149         } else {
 150                 rconn->source.in.next_seqno += skb->len;
 151                 drop = receive_skb(rconn, skb);
 152         }
 153
 154         if (drop) {
 155                 kfree_skb(skb);
 156                 free_control_msg(cm);
 157         } else {
 158                 send_ack(cm, rconn->source.in.nb, rconn->source.in.conn_id,
 159                                 ps->funcstate.rcv2.seqno);
 160         }
 161
 162         if (in_order)
 163                 drain_ooo_queue(rconn);
 164
 165         mutex_unlock(&(rconn->rcv_lock));
 166 out:
 167         ref_counter_decr(&(rconn->refs));
 168 }
 169
 170 static void conn_rcv(struct sk_buff *skb, __u32 conn_id, __u32 seqno)
 171 {
 172         struct skb_procstate *ps = skb_pstate(skb);
 173
 174         ps->funcstate.rcv2.conn_id = conn_id;
 175         ps->funcstate.rcv2.seqno = seqno;
 176
 177         ps->rconn = get_conn(ps->funcstate.rcv2.conn_id);
 178         _conn_rcv(skb);
 179 }
 180
 181 void conn_rcv_buildskb(char *data, __u32 datalen, __u32 conn_id, __u32 seqno)
 182 {
 183         struct sk_buff *skb = alloc_skb(datalen, GFP_KERNEL);
 184         char *dst = skb_put(skb, datalen);
 185         memcpy(dst, data, datalen);
 186         conn_rcv(skb, conn_id, seqno);
 187 }
 188
 189 static void rcv_data(struct sk_buff *skb)
 190 {
 191         __u32 conn_id;
 192         __u32 seqno;
 193
 194         char *connid_p = cor_pull_skb(skb, 4);
 195         char *seqno_p = cor_pull_skb(skb, 4);
 196
 197         ((char *)&conn_id)[0] = connid_p[0];
 198         ((char *)&conn_id)[1] = connid_p[1];
 199         ((char *)&conn_id)[2] = connid_p[2];
 200         ((char *)&conn_id)[3] = connid_p[3];
 201
 202         ((char *)&seqno)[0] = seqno_p[0];
 203         ((char *)&seqno)[1] = seqno_p[1];
 204         ((char *)&seqno)[2] = seqno_p[2];
 205         ((char *)&seqno)[3] = seqno_p[3];
 206
 207         conn_id = be32_to_cpu(conn_id);
 208         seqno = be32_to_cpu(seqno);
 209
 210         if (conn_id == 0) {
 211                 struct neighbor *nb = get_neigh_by_mac(skb);
 212                 printk(KERN_ERR "rcv kern");
 213                 if (nb == 0)
 214                         goto drop;
 215                 kernel_packet(nb, skb, seqno);
 216                 ref_counter_decr(&(nb->refs));
 217         } else {
 218                 printk(KERN_ERR "rcv conn");
 219                 conn_rcv(skb, conn_id, seqno);
 220         }
 221
 222         if (0) {
 223 drop:
 224                 kfree_skb(skb);
 225         }
 226 }
 227
 228 static void rcv(struct work_struct *work)
 229 {
 230         struct sk_buff *skb = skb_from_pstate(container_of(work,
 231                         struct skb_procstate, funcstate.rcv.work));
 232
 233         __u8 packet_type;
 234         char *packet_type_p;
 235
 236         atomic_dec(&packets_in_workqueue);
 237
 238         packet_type_p = cor_pull_skb(skb, 1);
 239
 240         if (packet_type_p == 0)
 241                 goto drop;
 242
 243         packet_type = *packet_type_p;
 244
 245         if (packet_type == PACKET_TYPE_ANNOUNCE) {
 246                 rcv_announce(skb);
 247                 return;
 248         }
 249
 250         if (packet_type != PACKET_TYPE_DATA)
 251                 goto drop;
 252
 253         rcv_data(skb);
 254
 255         if (0) {
 256 drop:
 257                 kfree_skb(skb);
 258         }
 259 }
 260
 261 static int queue_rcv_processing(struct sk_buff *skb, struct net_device *dev,
 262                struct packet_type *pt, struct net_device *orig_dev)
 263 {
 264         struct skb_procstate *ps = skb_pstate(skb);
 265         long queuelen;
 266
 267         BUG_ON(skb->next != 0);
 268
 269         queuelen = atomic_inc_return(&packets_in_workqueue);
 270
 271         BUG_ON(queuelen <= 0);
 272
 273         if (queuelen > MAX_PACKETS_IN_RCVQUEUE) {
 274                 atomic_dec(&packets_in_workqueue);
 275                 kfree_skb(skb);
 276                 return NET_RX_DROP;
 277         }
 278
 279         INIT_WORK(&(ps->funcstate.rcv.work), rcv);
 280         queue_work(packet_wq, &(ps->funcstate.rcv.work));
 281         return NET_RX_SUCCESS;
 282  }
 283
 284 static struct packet_type ptype_cor = {
 285         .type = htons(ETH_P_COR),
 286         .dev = 0,
 287         .func = queue_rcv_processing
 288 };
 289
 290 int __init cor_rcv_init(void)
 291 {
 292         BUG_ON(sizeof(struct skb_procstate) > 48);
 293         packet_wq = create_workqueue("cor_packet");
 294         dev_add_pack(&ptype_cor);
 295         return 0;
 296 }
 297
 298 MODULE_LICENSE("GPL");