net/ieee802154/6lowpan/tx.c

   1 /* This program is free software; you can redistribute it and/or modify
   2  * it under the terms of the GNU General Public License version 2
   3  * as published by the Free Software Foundation.
   4  *
   5  * This program is distributed in the hope that it will be useful,
   6  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   7  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   8  * GNU General Public License for more details.
   9  */
  10
  11 #include <net/6lowpan.h>
  12 #include <net/ieee802154_netdev.h>
  13
  14 #include "6lowpan_i.h"
  15
  16 /* don't save pan id, it's intra pan */
  17 struct lowpan_addr {
  18         u8 mode;
  19         union {
  20                 /* IPv6 needs big endian here */
  21                 __be64 extended_addr;
  22                 __be16 short_addr;
  23         } u;
  24 };
  25
  26 struct lowpan_addr_info {
  27         struct lowpan_addr daddr;
  28         struct lowpan_addr saddr;
  29 };
  30
  31 static inline struct
  32 lowpan_addr_info *lowpan_skb_priv(const struct sk_buff *skb)
  33 {
  34         WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct lowpan_addr_info));
  35         return (struct lowpan_addr_info *)(skb->data -
  36                         sizeof(struct lowpan_addr_info));
  37 }
  38
  39 int lowpan_header_create(struct sk_buff *skb, struct net_device *dev,
  40                          unsigned short type, const void *_daddr,
  41                          const void *_saddr, unsigned int len)
  42 {
  43         const u8 *saddr = _saddr;
  44         const u8 *daddr = _daddr;
  45         struct lowpan_addr_info *info;
  46
  47         /* TODO:
  48          * if this package isn't ipv6 one, where should it be routed?
  49          */
  50         if (type != ETH_P_IPV6)
  51                 return 0;
  52
  53         if (!saddr)
  54                 saddr = dev->dev_addr;
  55
  56         raw_dump_inline(__func__, "saddr", (unsigned char *)saddr, 8);
  57         raw_dump_inline(__func__, "daddr", (unsigned char *)daddr, 8);
  58
  59         info = lowpan_skb_priv(skb);
  60
  61         /* TODO: Currently we only support extended_addr */
  62         info->daddr.mode = IEEE802154_ADDR_LONG;
  63         memcpy(&info->daddr.u.extended_addr, daddr,
  64                sizeof(info->daddr.u.extended_addr));
  65         info->saddr.mode = IEEE802154_ADDR_LONG;
  66         memcpy(&info->saddr.u.extended_addr, saddr,
  67                sizeof(info->daddr.u.extended_addr));
  68
  69         return 0;
  70 }
  71
  72 static struct sk_buff*
  73 lowpan_alloc_frag(struct sk_buff *skb, int size,
  74                   const struct ieee802154_hdr *master_hdr)
  75 {
  76         struct net_device *real_dev = lowpan_dev_info(skb->dev)->real_dev;
  77         struct sk_buff *frag;
  78         int rc;
  79
  80         frag = alloc_skb(real_dev->hard_header_len +
  81                          real_dev->needed_tailroom + size,
  82                          GFP_ATOMIC);
  83
  84         if (likely(frag)) {
  85                 frag->dev = real_dev;
  86                 frag->priority = skb->priority;
  87                 skb_reserve(frag, real_dev->hard_header_len);
  88                 skb_reset_network_header(frag);
  89                 *mac_cb(frag) = *mac_cb(skb);
  90
  91                 rc = dev_hard_header(frag, real_dev, 0, &master_hdr->dest,
  92                                      &master_hdr->source, size);
  93                 if (rc < 0) {
  94                         kfree_skb(frag);
  95                         return ERR_PTR(rc);
  96                 }
  97         } else {
  98                 frag = ERR_PTR(-ENOMEM);
  99         }
 100
 101         return frag;
 102 }
 103
 104 static int
 105 lowpan_xmit_fragment(struct sk_buff *skb, const struct ieee802154_hdr *wpan_hdr,
 106                      u8 *frag_hdr, int frag_hdrlen,
 107                      int offset, int len)
 108 {
 109         struct sk_buff *frag;
 110
 111         raw_dump_inline(__func__, " fragment header", frag_hdr, frag_hdrlen);
 112
 113         frag = lowpan_alloc_frag(skb, frag_hdrlen + len, wpan_hdr);
 114         if (IS_ERR(frag))
 115                 return -PTR_ERR(frag);
 116
 117         memcpy(skb_put(frag, frag_hdrlen), frag_hdr, frag_hdrlen);
 118         memcpy(skb_put(frag, len), skb_network_header(skb) + offset, len);
 119
 120         raw_dump_table(__func__, " fragment dump", frag->data, frag->len);
 121
 122         return dev_queue_xmit(frag);
 123 }
 124
 125 static int
 126 lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *dev,
 127                        const struct ieee802154_hdr *wpan_hdr)
 128 {
 129         u16 dgram_size, dgram_offset;
 130         __be16 frag_tag;
 131         u8 frag_hdr[5];
 132         int frag_cap, frag_len, payload_cap, rc;
 133         int skb_unprocessed, skb_offset;
 134
 135         dgram_size = lowpan_uncompress_size(skb, &dgram_offset) -
 136                      skb->mac_len;
 137         frag_tag = htons(lowpan_dev_info(dev)->fragment_tag);
 138         lowpan_dev_info(dev)->fragment_tag++;
 139
 140         frag_hdr[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x07);
 141         frag_hdr[1] = dgram_size & 0xff;
 142         memcpy(frag_hdr + 2, &frag_tag, sizeof(frag_tag));
 143
 144         payload_cap = ieee802154_max_payload(wpan_hdr);
 145
 146         frag_len = round_down(payload_cap - LOWPAN_FRAG1_HEAD_SIZE -
 147                               skb_network_header_len(skb), 8);
 148
 149         skb_offset = skb_network_header_len(skb);
 150         skb_unprocessed = skb->len - skb->mac_len - skb_offset;
 151
 152         rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
 153                                   LOWPAN_FRAG1_HEAD_SIZE, 0,
 154                                   frag_len + skb_network_header_len(skb));
 155         if (rc) {
 156                 pr_debug("%s unable to send FRAG1 packet (tag: %d)",
 157                          __func__, ntohs(frag_tag));
 158                 goto err;
 159         }
 160
 161         frag_hdr[0] &= ~LOWPAN_DISPATCH_FRAG1;
 162         frag_hdr[0] |= LOWPAN_DISPATCH_FRAGN;
 163         frag_cap = round_down(payload_cap - LOWPAN_FRAGN_HEAD_SIZE, 8);
 164
 165         do {
 166                 dgram_offset += frag_len;
 167                 skb_offset += frag_len;
 168                 skb_unprocessed -= frag_len;
 169                 frag_len = min(frag_cap, skb_unprocessed);
 170
 171                 frag_hdr[4] = dgram_offset >> 3;
 172
 173                 rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
 174                                           LOWPAN_FRAGN_HEAD_SIZE, skb_offset,
 175                                           frag_len);
 176                 if (rc) {
 177                         pr_debug("%s unable to send a FRAGN packet. (tag: %d, offset: %d)\n",
 178                                  __func__, ntohs(frag_tag), skb_offset);
 179                         goto err;
 180                 }
 181         } while (skb_unprocessed > frag_cap);
 182
 183         consume_skb(skb);
 184         return NET_XMIT_SUCCESS;
 185
 186 err:
 187         kfree_skb(skb);
 188         return rc;
 189 }
 190
 191 static int lowpan_header(struct sk_buff *skb, struct net_device *dev)
 192 {
 193         struct ieee802154_addr sa, da;
 194         struct ieee802154_mac_cb *cb = mac_cb_init(skb);
 195         struct lowpan_addr_info info;
 196         void *daddr, *saddr;
 197
 198         memcpy(&info, lowpan_skb_priv(skb), sizeof(info));
 199
 200         /* TODO: Currently we only support extended_addr */
 201         daddr = &info.daddr.u.extended_addr;
 202         saddr = &info.saddr.u.extended_addr;
 203
 204         lowpan_header_compress(skb, dev, ETH_P_IPV6, daddr, saddr, skb->len);
 205
 206         cb->type = IEEE802154_FC_TYPE_DATA;
 207
 208         /* prepare wpan address data */
 209         sa.mode = IEEE802154_ADDR_LONG;
 210         sa.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);
 211         sa.extended_addr = ieee802154_devaddr_from_raw(saddr);
 212
 213         /* intra-PAN communications */
 214         da.pan_id = sa.pan_id;
 215
 216         /* if the destination address is the broadcast address, use the
 217          * corresponding short address
 218          */
 219         if (lowpan_is_addr_broadcast((const u8 *)daddr)) {
 220                 da.mode = IEEE802154_ADDR_SHORT;
 221                 da.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
 222                 cb->ackreq = false;
 223         } else {
 224                 da.mode = IEEE802154_ADDR_LONG;
 225                 da.extended_addr = ieee802154_devaddr_from_raw(daddr);
 226                 cb->ackreq = true;
 227         }
 228
 229         return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,
 230                         ETH_P_IPV6, (void *)&da, (void *)&sa, 0);
 231 }
 232
 233 netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev)
 234 {
 235         struct ieee802154_hdr wpan_hdr;
 236         int max_single, ret;
 237
 238         pr_debug("package xmit\n");
 239
 240         /* We must take a copy of the skb before we modify/replace the ipv6
 241          * header as the header could be used elsewhere
 242          */
 243         skb = skb_unshare(skb, GFP_ATOMIC);
 244         if (!skb)
 245                 return NET_XMIT_DROP;
 246
 247         ret = lowpan_header(skb, dev);
 248         if (ret < 0) {
 249                 kfree_skb(skb);
 250                 return NET_XMIT_DROP;
 251         }
 252
 253         if (ieee802154_hdr_peek(skb, &wpan_hdr) < 0) {
 254                 kfree_skb(skb);
 255                 return NET_XMIT_DROP;
 256         }
 257
 258         max_single = ieee802154_max_payload(&wpan_hdr);
 259
 260         if (skb_tail_pointer(skb) - skb_network_header(skb) <= max_single) {
 261                 skb->dev = lowpan_dev_info(dev)->real_dev;
 262                 return dev_queue_xmit(skb);
 263         } else {
 264                 netdev_tx_t rc;
 265
 266                 pr_debug("frame is too big, fragmentation is needed\n");
 267                 rc = lowpan_xmit_fragmented(skb, dev, &wpan_hdr);
 268
 269                 return rc < 0 ? NET_XMIT_DROP : rc;
 270         }
 271 }