net/mac802154/rx.c

   1 /*
   2  * Copyright (C) 2007-2012 Siemens AG
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * Written by:
  14  * Pavel Smolenskiy <pavel.smolenskiy@gmail.com>
  15  * Maxim Gorbachyov <maxim.gorbachev@siemens.com>
  16  * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
  17  * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
  18  */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/crc-ccitt.h>
  24 #include <asm/unaligned.h>
  25
  26 #include <net/mac802154.h>
  27 #include <net/ieee802154_netdev.h>
  28 #include <net/nl802154.h>
  29
  30 #include "ieee802154_i.h"
  31
  32 static int ieee802154_deliver_skb(struct sk_buff *skb)
  33 {
  34         skb->ip_summed = CHECKSUM_UNNECESSARY;
  35         skb->protocol = htons(ETH_P_IEEE802154);
  36
  37         return netif_receive_skb(skb);
  38 }
  39
  40 static int
  41 ieee802154_subif_frame(struct ieee802154_sub_if_data *sdata,
  42                        struct sk_buff *skb, const struct ieee802154_hdr *hdr)
  43 {
  44         struct wpan_dev *wpan_dev = &sdata->wpan_dev;
  45         __le16 span, sshort;
  46         int rc;
  47
  48         pr_debug("getting packet via slave interface %s\n", sdata->dev->name);
  49
  50         span = wpan_dev->pan_id;
  51         sshort = wpan_dev->short_addr;
  52
  53         switch (mac_cb(skb)->dest.mode) {
  54         case IEEE802154_ADDR_NONE:
  55                 if (mac_cb(skb)->dest.mode != IEEE802154_ADDR_NONE)
  56                         /* FIXME: check if we are PAN coordinator */
  57                         skb->pkt_type = PACKET_OTHERHOST;
  58                 else
  59                         /* ACK comes with both addresses empty */
  60                         skb->pkt_type = PACKET_HOST;
  61                 break;
  62         case IEEE802154_ADDR_LONG:
  63                 if (mac_cb(skb)->dest.pan_id != span &&
  64                     mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST))
  65                         skb->pkt_type = PACKET_OTHERHOST;
  66                 else if (mac_cb(skb)->dest.extended_addr == wpan_dev->extended_addr)
  67                         skb->pkt_type = PACKET_HOST;
  68                 else
  69                         skb->pkt_type = PACKET_OTHERHOST;
  70                 break;
  71         case IEEE802154_ADDR_SHORT:
  72                 if (mac_cb(skb)->dest.pan_id != span &&
  73                     mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST))
  74                         skb->pkt_type = PACKET_OTHERHOST;
  75                 else if (mac_cb(skb)->dest.short_addr == sshort)
  76                         skb->pkt_type = PACKET_HOST;
  77                 else if (mac_cb(skb)->dest.short_addr ==
  78                           cpu_to_le16(IEEE802154_ADDR_BROADCAST))
  79                         skb->pkt_type = PACKET_BROADCAST;
  80                 else
  81                         skb->pkt_type = PACKET_OTHERHOST;
  82                 break;
  83         default:
  84                 pr_debug("invalid dest mode\n");
  85                 goto fail;
  86         }
  87
  88         skb->dev = sdata->dev;
  89
  90         /* TODO this should be moved after netif_receive_skb call, otherwise
  91          * wireshark will show a mac header with security fields and the
  92          * payload is already decrypted.
  93          */
  94         rc = mac802154_llsec_decrypt(&sdata->sec, skb);
  95         if (rc) {
  96                 pr_debug("decryption failed: %i\n", rc);
  97                 goto fail;
  98         }
  99
 100         sdata->dev->stats.rx_packets++;
 101         sdata->dev->stats.rx_bytes += skb->len;
 102
 103         switch (mac_cb(skb)->type) {
 104         case IEEE802154_FC_TYPE_DATA:
 105                 return ieee802154_deliver_skb(skb);
 106         default:
 107                 pr_warn("ieee802154: bad frame received (type = %d)\n",
 108                         mac_cb(skb)->type);
 109                 goto fail;
 110         }
 111
 112 fail:
 113         kfree_skb(skb);
 114         return NET_RX_DROP;
 115 }
 116
 117 static void
 118 ieee802154_print_addr(const char *name, const struct ieee802154_addr *addr)
 119 {
 120         if (addr->mode == IEEE802154_ADDR_NONE)
 121                 pr_debug("%s not present\n", name);
 122
 123         pr_debug("%s PAN ID: %04x\n", name, le16_to_cpu(addr->pan_id));
 124         if (addr->mode == IEEE802154_ADDR_SHORT) {
 125                 pr_debug("%s is short: %04x\n", name,
 126                          le16_to_cpu(addr->short_addr));
 127         } else {
 128                 u64 hw = swab64((__force u64)addr->extended_addr);
 129
 130                 pr_debug("%s is hardware: %8phC\n", name, &hw);
 131         }
 132 }
 133
 134 static int
 135 ieee802154_parse_frame_start(struct sk_buff *skb, struct ieee802154_hdr *hdr)
 136 {
 137         int hlen;
 138         struct ieee802154_mac_cb *cb = mac_cb_init(skb);
 139
 140         skb_reset_mac_header(skb);
 141
 142         hlen = ieee802154_hdr_pull(skb, hdr);
 143         if (hlen < 0)
 144                 return -EINVAL;
 145
 146         skb->mac_len = hlen;
 147
 148         pr_debug("fc: %04x dsn: %02x\n", le16_to_cpup((__le16 *)&hdr->fc),
 149                  hdr->seq);
 150
 151         cb->type = hdr->fc.type;
 152         cb->ackreq = hdr->fc.ack_request;
 153         cb->secen = hdr->fc.security_enabled;
 154
 155         ieee802154_print_addr("destination", &hdr->dest);
 156         ieee802154_print_addr("source", &hdr->source);
 157
 158         cb->source = hdr->source;
 159         cb->dest = hdr->dest;
 160
 161         if (hdr->fc.security_enabled) {
 162                 u64 key;
 163
 164                 pr_debug("seclevel %i\n", hdr->sec.level);
 165
 166                 switch (hdr->sec.key_id_mode) {
 167                 case IEEE802154_SCF_KEY_IMPLICIT:
 168                         pr_debug("implicit key\n");
 169                         break;
 170
 171                 case IEEE802154_SCF_KEY_INDEX:
 172                         pr_debug("key %02x\n", hdr->sec.key_id);
 173                         break;
 174
 175                 case IEEE802154_SCF_KEY_SHORT_INDEX:
 176                         pr_debug("key %04x:%04x %02x\n",
 177                                  le32_to_cpu(hdr->sec.short_src) >> 16,
 178                                  le32_to_cpu(hdr->sec.short_src) & 0xffff,
 179                                  hdr->sec.key_id);
 180                         break;
 181
 182                 case IEEE802154_SCF_KEY_HW_INDEX:
 183                         key = swab64((__force u64)hdr->sec.extended_src);
 184                         pr_debug("key source %8phC %02x\n", &key,
 185                                  hdr->sec.key_id);
 186                         break;
 187                 }
 188         }
 189
 190         return 0;
 191 }
 192
 193 static void
 194 __ieee802154_rx_handle_packet(struct ieee802154_local *local,
 195                               struct sk_buff *skb)
 196 {
 197         int ret;
 198         struct ieee802154_sub_if_data *sdata;
 199         struct ieee802154_hdr hdr;
 200
 201         ret = ieee802154_parse_frame_start(skb, &hdr);
 202         if (ret) {
 203                 pr_debug("got invalid frame\n");
 204                 kfree_skb(skb);
 205                 return;
 206         }
 207
 208         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 209                 if (sdata->wpan_dev.iftype != NL802154_IFTYPE_NODE)
 210                         continue;
 211
 212                 if (!ieee802154_sdata_running(sdata))
 213                         continue;
 214
 215                 ieee802154_subif_frame(sdata, skb, &hdr);
 216                 skb = NULL;
 217                 break;
 218         }
 219
 220         if (skb)
 221                 kfree_skb(skb);
 222 }
 223
 224 static void
 225 ieee802154_monitors_rx(struct ieee802154_local *local, struct sk_buff *skb)
 226 {
 227         struct sk_buff *skb2;
 228         struct ieee802154_sub_if_data *sdata;
 229
 230         skb_reset_mac_header(skb);
 231         skb->ip_summed = CHECKSUM_UNNECESSARY;
 232         skb->pkt_type = PACKET_OTHERHOST;
 233         skb->protocol = htons(ETH_P_IEEE802154);
 234
 235         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 236                 if (sdata->wpan_dev.iftype != NL802154_IFTYPE_MONITOR)
 237                         continue;
 238
 239                 if (!ieee802154_sdata_running(sdata))
 240                         continue;
 241
 242                 skb2 = skb_clone(skb, GFP_ATOMIC);
 243                 if (skb2) {
 244                         skb2->dev = sdata->dev;
 245                         ieee802154_deliver_skb(skb2);
 246
 247                         sdata->dev->stats.rx_packets++;
 248                         sdata->dev->stats.rx_bytes += skb->len;
 249                 }
 250         }
 251 }
 252
 253 void ieee802154_rx(struct ieee802154_local *local, struct sk_buff *skb)
 254 {
 255         u16 crc;
 256
 257         WARN_ON_ONCE(softirq_count() == 0);
 258
 259         if (local->suspended)
 260                 goto drop;
 261
 262         /* TODO: When a transceiver omits the checksum here, we
 263          * add an own calculated one. This is currently an ugly
 264          * solution because the monitor needs a crc here.
 265          */
 266         if (local->hw.flags & IEEE802154_HW_RX_OMIT_CKSUM) {
 267                 crc = crc_ccitt(0, skb->data, skb->len);
 268                 put_unaligned_le16(crc, skb_put(skb, 2));
 269         }
 270
 271         rcu_read_lock();
 272
 273         ieee802154_monitors_rx(local, skb);
 274
 275         /* Check if transceiver doesn't validate the checksum.
 276          * If not we validate the checksum here.
 277          */
 278         if (local->hw.flags & IEEE802154_HW_RX_DROP_BAD_CKSUM) {
 279                 crc = crc_ccitt(0, skb->data, skb->len);
 280                 if (crc) {
 281                         rcu_read_unlock();
 282                         goto drop;
 283                 }
 284         }
 285         /* remove crc */
 286         skb_trim(skb, skb->len - 2);
 287
 288         __ieee802154_rx_handle_packet(local, skb);
 289
 290         rcu_read_unlock();
 291
 292         return;
 293 drop:
 294         kfree_skb(skb);
 295 }
 296
 297 void
 298 ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi)
 299 {
 300         struct ieee802154_local *local = hw_to_local(hw);
 301
 302         mac_cb(skb)->lqi = lqi;
 303         skb->pkt_type = IEEE802154_RX_MSG;
 304         skb_queue_tail(&local->skb_queue, skb);
 305         tasklet_schedule(&local->tasklet);
 306 }
 307 EXPORT_SYMBOL(ieee802154_rx_irqsafe);