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 *ldev,
  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 = ldev->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 *wdev = lowpan_dev_info(skb->dev)->wdev;
  77         struct sk_buff *frag;
  78         int rc;
  79
  80         frag = alloc_skb(wdev->hard_header_len + wdev->needed_tailroom + size,
  81                          GFP_ATOMIC);
  82
  83         if (likely(frag)) {
  84                 frag->dev = wdev;
  85                 frag->priority = skb->priority;
  86                 skb_reserve(frag, wdev->hard_header_len);
  87                 skb_reset_network_header(frag);
  88                 *mac_cb(frag) = *mac_cb(skb);
  89
  90                 rc = dev_hard_header(frag, wdev, 0, &master_hdr->dest,
  91                                      &master_hdr->source, size);
  92                 if (rc < 0) {
  93                         kfree_skb(frag);
  94                         return ERR_PTR(rc);
  95                 }
  96         } else {
  97                 frag = ERR_PTR(-ENOMEM);
  98         }
  99
 100         return frag;
 101 }
 102
 103 static int
 104 lowpan_xmit_fragment(struct sk_buff *skb, const struct ieee802154_hdr *wpan_hdr,
 105                      u8 *frag_hdr, int frag_hdrlen,
 106                      int offset, int len)
 107 {
 108         struct sk_buff *frag;
 109
 110         raw_dump_inline(__func__, " fragment header", frag_hdr, frag_hdrlen);
 111
 112         frag = lowpan_alloc_frag(skb, frag_hdrlen + len, wpan_hdr);
 113         if (IS_ERR(frag))
 114                 return PTR_ERR(frag);
 115
 116         memcpy(skb_put(frag, frag_hdrlen), frag_hdr, frag_hdrlen);
 117         memcpy(skb_put(frag, len), skb_network_header(skb) + offset, len);
 118
 119         raw_dump_table(__func__, " fragment dump", frag->data, frag->len);
 120
 121         return dev_queue_xmit(frag);
 122 }
 123
 124 static int
 125 lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *ldev,
 126                        const struct ieee802154_hdr *wpan_hdr, u16 dgram_size,
 127                        u16 dgram_offset)
 128 {
 129         __be16 frag_tag;
 130         u8 frag_hdr[5];
 131         int frag_cap, frag_len, payload_cap, rc;
 132         int skb_unprocessed, skb_offset;
 133
 134         frag_tag = htons(lowpan_dev_info(ldev)->fragment_tag);
 135         lowpan_dev_info(ldev)->fragment_tag++;
 136
 137         frag_hdr[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x07);
 138         frag_hdr[1] = dgram_size & 0xff;
 139         memcpy(frag_hdr + 2, &frag_tag, sizeof(frag_tag));
 140
 141         payload_cap = ieee802154_max_payload(wpan_hdr);
 142
 143         frag_len = round_down(payload_cap - LOWPAN_FRAG1_HEAD_SIZE -
 144                               skb_network_header_len(skb), 8);
 145
 146         skb_offset = skb_network_header_len(skb);
 147         skb_unprocessed = skb->len - skb->mac_len - skb_offset;
 148
 149         rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
 150                                   LOWPAN_FRAG1_HEAD_SIZE, 0,
 151                                   frag_len + skb_network_header_len(skb));
 152         if (rc) {
 153                 pr_debug("%s unable to send FRAG1 packet (tag: %d)",
 154                          __func__, ntohs(frag_tag));
 155                 goto err;
 156         }
 157
 158         frag_hdr[0] &= ~LOWPAN_DISPATCH_FRAG1;
 159         frag_hdr[0] |= LOWPAN_DISPATCH_FRAGN;
 160         frag_cap = round_down(payload_cap - LOWPAN_FRAGN_HEAD_SIZE, 8);
 161
 162         do {
 163                 dgram_offset += frag_len;
 164                 skb_offset += frag_len;
 165                 skb_unprocessed -= frag_len;
 166                 frag_len = min(frag_cap, skb_unprocessed);
 167
 168                 frag_hdr[4] = dgram_offset >> 3;
 169
 170                 rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
 171                                           LOWPAN_FRAGN_HEAD_SIZE, skb_offset,
 172                                           frag_len);
 173                 if (rc) {
 174                         pr_debug("%s unable to send a FRAGN packet. (tag: %d, offset: %d)\n",
 175                                  __func__, ntohs(frag_tag), skb_offset);
 176                         goto err;
 177                 }
 178         } while (skb_unprocessed > frag_cap);
 179
 180         consume_skb(skb);
 181         return NET_XMIT_SUCCESS;
 182
 183 err:
 184         kfree_skb(skb);
 185         return rc;
 186 }
 187
 188 static int lowpan_header(struct sk_buff *skb, struct net_device *ldev,
 189                          u16 *dgram_size, u16 *dgram_offset)
 190 {
 191         struct wpan_dev *wpan_dev = lowpan_dev_info(ldev)->wdev->ieee802154_ptr;
 192         struct ieee802154_addr sa, da;
 193         struct ieee802154_mac_cb *cb = mac_cb_init(skb);
 194         struct lowpan_addr_info info;
 195         void *daddr, *saddr;
 196
 197         memcpy(&info, lowpan_skb_priv(skb), sizeof(info));
 198
 199         /* TODO: Currently we only support extended_addr */
 200         daddr = &info.daddr.u.extended_addr;
 201         saddr = &info.saddr.u.extended_addr;
 202
 203         *dgram_size = skb->len;
 204         lowpan_header_compress(skb, ldev, ETH_P_IPV6, daddr, saddr, skb->len);
 205         /* dgram_offset = (saved bytes after compression) + lowpan header len */
 206         *dgram_offset = (*dgram_size - skb->len) + skb_network_header_len(skb);
 207
 208         cb->type = IEEE802154_FC_TYPE_DATA;
 209
 210         /* prepare wpan address data */
 211         sa.mode = IEEE802154_ADDR_LONG;
 212         sa.pan_id = wpan_dev->pan_id;
 213         sa.extended_addr = ieee802154_devaddr_from_raw(saddr);
 214
 215         /* intra-PAN communications */
 216         da.pan_id = sa.pan_id;
 217
 218         /* if the destination address is the broadcast address, use the
 219          * corresponding short address
 220          */
 221         if (lowpan_is_addr_broadcast((const u8 *)daddr)) {
 222                 da.mode = IEEE802154_ADDR_SHORT;
 223                 da.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
 224                 cb->ackreq = false;
 225         } else {
 226                 da.mode = IEEE802154_ADDR_LONG;
 227                 da.extended_addr = ieee802154_devaddr_from_raw(daddr);
 228                 cb->ackreq = wpan_dev->ackreq;
 229         }
 230
 231         return dev_hard_header(skb, lowpan_dev_info(ldev)->wdev, ETH_P_IPV6,
 232                                (void *)&da, (void *)&sa, 0);
 233 }
 234
 235 netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev)
 236 {
 237         struct ieee802154_hdr wpan_hdr;
 238         int max_single, ret;
 239         u16 dgram_size, dgram_offset;
 240
 241         pr_debug("package xmit\n");
 242
 243         /* We must take a copy of the skb before we modify/replace the ipv6
 244          * header as the header could be used elsewhere
 245          */
 246         skb = skb_unshare(skb, GFP_ATOMIC);
 247         if (!skb)
 248                 return NET_XMIT_DROP;
 249
 250         ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset);
 251         if (ret < 0) {
 252                 kfree_skb(skb);
 253                 return NET_XMIT_DROP;
 254         }
 255
 256         if (ieee802154_hdr_peek(skb, &wpan_hdr) < 0) {
 257                 kfree_skb(skb);
 258                 return NET_XMIT_DROP;
 259         }
 260
 261         max_single = ieee802154_max_payload(&wpan_hdr);
 262
 263         if (skb_tail_pointer(skb) - skb_network_header(skb) <= max_single) {
 264                 skb->dev = lowpan_dev_info(ldev)->wdev;
 265                 return dev_queue_xmit(skb);
 266         } else {
 267                 netdev_tx_t rc;
 268
 269                 pr_debug("frame is too big, fragmentation is needed\n");
 270                 rc = lowpan_xmit_fragmented(skb, ldev, &wpan_hdr, dgram_size,
 271                                             dgram_offset);
 272
 273                 return rc < 0 ? NET_XMIT_DROP : rc;
 274         }
 275 }