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/ndisc.h> 13 #include <net/ieee802154_netdev.h> 14 #include <net/mac802154.h> 15 16 #include "6lowpan_i.h" 17 18 #define LOWPAN_FRAG1_HEAD_SIZE 0x4 19 #define LOWPAN_FRAGN_HEAD_SIZE 0x5 20 21 struct lowpan_addr_info { 22 struct ieee802154_addr daddr; 23 struct ieee802154_addr saddr; 24 }; 25 26 static inline struct 27 lowpan_addr_info *lowpan_skb_priv(const struct sk_buff *skb) 28 { 29 WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct lowpan_addr_info)); 30 return (struct lowpan_addr_info *)(skb->data - 31 sizeof(struct lowpan_addr_info)); 32 } 33 34 /* This callback will be called from AF_PACKET and IPv6 stack, the AF_PACKET 35 * sockets gives an 8 byte array for addresses only! 36 * 37 * TODO I think AF_PACKET DGRAM (sending/receiving) RAW (sending) makes no 38 * sense here. We should disable it, the right use-case would be AF_INET6 39 * RAW/DGRAM sockets. 40 */ 41 int lowpan_header_create(struct sk_buff *skb, struct net_device *ldev, 42 unsigned short type, const void *daddr, 43 const void *saddr, unsigned int len) 44 { 45 struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr; 46 struct lowpan_addr_info *info = lowpan_skb_priv(skb); 47 struct lowpan_802154_neigh *llneigh = NULL; 48 const struct ipv6hdr *hdr = ipv6_hdr(skb); 49 struct neighbour *n; 50 51 /* TODO: 52 * if this package isn't ipv6 one, where should it be routed? 53 */ 54 if (type != ETH_P_IPV6) 55 return 0; 56 57 /* intra-pan communication */ 58 info->saddr.pan_id = wpan_dev->pan_id; 59 info->daddr.pan_id = info->saddr.pan_id; 60 61 if (!memcmp(daddr, ldev->broadcast, EUI64_ADDR_LEN)) { 62 info->daddr.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST); 63 info->daddr.mode = IEEE802154_ADDR_SHORT; 64 } else { 65 __le16 short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC); 66 67 n = neigh_lookup(&nd_tbl, &hdr->daddr, ldev); 68 if (n) { 69 llneigh = lowpan_802154_neigh(neighbour_priv(n)); 70 read_lock_bh(&n->lock); 71 short_addr = llneigh->short_addr; 72 read_unlock_bh(&n->lock); 73 } 74 75 if (llneigh && 76 lowpan_802154_is_valid_src_short_addr(short_addr)) { 77 info->daddr.short_addr = short_addr; 78 info->daddr.mode = IEEE802154_ADDR_SHORT; 79 } else { 80 info->daddr.mode = IEEE802154_ADDR_LONG; 81 ieee802154_be64_to_le64(&info->daddr.extended_addr, 82 daddr); 83 } 84 85 if (n) 86 neigh_release(n); 87 } 88 89 if (!saddr) { 90 if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr)) { 91 info->saddr.mode = IEEE802154_ADDR_SHORT; 92 info->saddr.short_addr = wpan_dev->short_addr; 93 } else { 94 info->saddr.mode = IEEE802154_ADDR_LONG; 95 info->saddr.extended_addr = wpan_dev->extended_addr; 96 } 97 } else { 98 info->saddr.mode = IEEE802154_ADDR_LONG; 99 ieee802154_be64_to_le64(&info->saddr.extended_addr, saddr); 100 } 101 102 return 0; 103 } 104 105 static struct sk_buff* 106 lowpan_alloc_frag(struct sk_buff *skb, int size, 107 const struct ieee802154_hdr *master_hdr, bool frag1) 108 { 109 struct net_device *wdev = lowpan_802154_dev(skb->dev)->wdev; 110 struct sk_buff *frag; 111 int rc; 112 113 frag = alloc_skb(wdev->needed_headroom + wdev->needed_tailroom + size, 114 GFP_ATOMIC); 115 116 if (likely(frag)) { 117 frag->dev = wdev; 118 frag->priority = skb->priority; 119 skb_reserve(frag, wdev->needed_headroom); 120 skb_reset_network_header(frag); 121 *mac_cb(frag) = *mac_cb(skb); 122 123 if (frag1) { 124 skb_put_data(frag, skb_mac_header(skb), skb->mac_len); 125 } else { 126 rc = wpan_dev_hard_header(frag, wdev, 127 &master_hdr->dest, 128 &master_hdr->source, size); 129 if (rc < 0) { 130 kfree_skb(frag); 131 return ERR_PTR(rc); 132 } 133 } 134 } else { 135 frag = ERR_PTR(-ENOMEM); 136 } 137 138 return frag; 139 } 140 141 static int 142 lowpan_xmit_fragment(struct sk_buff *skb, const struct ieee802154_hdr *wpan_hdr, 143 u8 *frag_hdr, int frag_hdrlen, 144 int offset, int len, bool frag1) 145 { 146 struct sk_buff *frag; 147 148 raw_dump_inline(__func__, " fragment header", frag_hdr, frag_hdrlen); 149 150 frag = lowpan_alloc_frag(skb, frag_hdrlen + len, wpan_hdr, frag1); 151 if (IS_ERR(frag)) 152 return PTR_ERR(frag); 153 154 skb_put_data(frag, frag_hdr, frag_hdrlen); 155 skb_put_data(frag, skb_network_header(skb) + offset, len); 156 157 raw_dump_table(__func__, " fragment dump", frag->data, frag->len); 158 159 return dev_queue_xmit(frag); 160 } 161 162 static int 163 lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *ldev, 164 const struct ieee802154_hdr *wpan_hdr, u16 dgram_size, 165 u16 dgram_offset) 166 { 167 __be16 frag_tag; 168 u8 frag_hdr[5]; 169 int frag_cap, frag_len, payload_cap, rc; 170 int skb_unprocessed, skb_offset; 171 172 frag_tag = htons(lowpan_802154_dev(ldev)->fragment_tag); 173 lowpan_802154_dev(ldev)->fragment_tag++; 174 175 frag_hdr[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x07); 176 frag_hdr[1] = dgram_size & 0xff; 177 memcpy(frag_hdr + 2, &frag_tag, sizeof(frag_tag)); 178 179 payload_cap = ieee802154_max_payload(wpan_hdr); 180 181 frag_len = round_down(payload_cap - LOWPAN_FRAG1_HEAD_SIZE - 182 skb_network_header_len(skb), 8); 183 184 skb_offset = skb_network_header_len(skb); 185 skb_unprocessed = skb->len - skb->mac_len - skb_offset; 186 187 rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr, 188 LOWPAN_FRAG1_HEAD_SIZE, 0, 189 frag_len + skb_network_header_len(skb), 190 true); 191 if (rc) { 192 pr_debug("%s unable to send FRAG1 packet (tag: %d)", 193 __func__, ntohs(frag_tag)); 194 goto err; 195 } 196 197 frag_hdr[0] &= ~LOWPAN_DISPATCH_FRAG1; 198 frag_hdr[0] |= LOWPAN_DISPATCH_FRAGN; 199 frag_cap = round_down(payload_cap - LOWPAN_FRAGN_HEAD_SIZE, 8); 200 201 do { 202 dgram_offset += frag_len; 203 skb_offset += frag_len; 204 skb_unprocessed -= frag_len; 205 frag_len = min(frag_cap, skb_unprocessed); 206 207 frag_hdr[4] = dgram_offset >> 3; 208 209 rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr, 210 LOWPAN_FRAGN_HEAD_SIZE, skb_offset, 211 frag_len, false); 212 if (rc) { 213 pr_debug("%s unable to send a FRAGN packet. (tag: %d, offset: %d)\n", 214 __func__, ntohs(frag_tag), skb_offset); 215 goto err; 216 } 217 } while (skb_unprocessed > frag_cap); 218 219 ldev->stats.tx_packets++; 220 ldev->stats.tx_bytes += dgram_size; 221 consume_skb(skb); 222 return NET_XMIT_SUCCESS; 223 224 err: 225 kfree_skb(skb); 226 return rc; 227 } 228 229 static int lowpan_header(struct sk_buff *skb, struct net_device *ldev, 230 u16 *dgram_size, u16 *dgram_offset) 231 { 232 struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr; 233 struct ieee802154_mac_cb *cb = mac_cb_init(skb); 234 struct lowpan_addr_info info; 235 236 memcpy(&info, lowpan_skb_priv(skb), sizeof(info)); 237 238 *dgram_size = skb->len; 239 lowpan_header_compress(skb, ldev, &info.daddr, &info.saddr); 240 /* dgram_offset = (saved bytes after compression) + lowpan header len */ 241 *dgram_offset = (*dgram_size - skb->len) + skb_network_header_len(skb); 242 243 cb->type = IEEE802154_FC_TYPE_DATA; 244 245 if (info.daddr.mode == IEEE802154_ADDR_SHORT && 246 ieee802154_is_broadcast_short_addr(info.daddr.short_addr)) 247 cb->ackreq = false; 248 else 249 cb->ackreq = wpan_dev->ackreq; 250 251 return wpan_dev_hard_header(skb, lowpan_802154_dev(ldev)->wdev, 252 &info.daddr, &info.saddr, 0); 253 } 254 255 netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev) 256 { 257 struct ieee802154_hdr wpan_hdr; 258 int max_single, ret; 259 u16 dgram_size, dgram_offset; 260 261 pr_debug("package xmit\n"); 262 263 WARN_ON_ONCE(skb->len > IPV6_MIN_MTU); 264 265 /* We must take a copy of the skb before we modify/replace the ipv6 266 * header as the header could be used elsewhere 267 */ 268 skb = skb_unshare(skb, GFP_ATOMIC); 269 if (!skb) 270 return NET_XMIT_DROP; 271 272 ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset); 273 if (ret < 0) { 274 kfree_skb(skb); 275 return NET_XMIT_DROP; 276 } 277 278 if (ieee802154_hdr_peek(skb, &wpan_hdr) < 0) { 279 kfree_skb(skb); 280 return NET_XMIT_DROP; 281 } 282 283 max_single = ieee802154_max_payload(&wpan_hdr); 284 285 if (skb_tail_pointer(skb) - skb_network_header(skb) <= max_single) { 286 skb->dev = lowpan_802154_dev(ldev)->wdev; 287 ldev->stats.tx_packets++; 288 ldev->stats.tx_bytes += dgram_size; 289 return dev_queue_xmit(skb); 290 } else { 291 netdev_tx_t rc; 292 293 pr_debug("frame is too big, fragmentation is needed\n"); 294 rc = lowpan_xmit_fragmented(skb, ldev, &wpan_hdr, dgram_size, 295 dgram_offset); 296 297 return rc < 0 ? NET_XMIT_DROP : rc; 298 } 299 } 300