1 // SPDX-License-Identifier: GPL-2.0-only 2 3 #include <net/6lowpan.h> 4 #include <net/ndisc.h> 5 #include <net/ieee802154_netdev.h> 6 #include <net/mac802154.h> 7 8 #include "6lowpan_i.h" 9 10 #define LOWPAN_FRAG1_HEAD_SIZE 0x4 11 #define LOWPAN_FRAGN_HEAD_SIZE 0x5 12 13 struct lowpan_addr_info { 14 struct ieee802154_addr daddr; 15 struct ieee802154_addr saddr; 16 }; 17 18 static inline struct 19 lowpan_addr_info *lowpan_skb_priv(const struct sk_buff *skb) 20 { 21 WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct lowpan_addr_info)); 22 return (struct lowpan_addr_info *)(skb->data - 23 sizeof(struct lowpan_addr_info)); 24 } 25 26 /* This callback will be called from AF_PACKET and IPv6 stack, the AF_PACKET 27 * sockets gives an 8 byte array for addresses only! 28 * 29 * TODO I think AF_PACKET DGRAM (sending/receiving) RAW (sending) makes no 30 * sense here. We should disable it, the right use-case would be AF_INET6 31 * RAW/DGRAM sockets. 32 */ 33 int lowpan_header_create(struct sk_buff *skb, struct net_device *ldev, 34 unsigned short type, const void *daddr, 35 const void *saddr, unsigned int len) 36 { 37 struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr; 38 struct lowpan_addr_info *info = lowpan_skb_priv(skb); 39 struct lowpan_802154_neigh *llneigh = NULL; 40 const struct ipv6hdr *hdr = ipv6_hdr(skb); 41 struct neighbour *n; 42 43 if (!daddr) 44 return -EINVAL; 45 46 /* TODO: 47 * if this package isn't ipv6 one, where should it be routed? 48 */ 49 if (type != ETH_P_IPV6) 50 return 0; 51 52 /* intra-pan communication */ 53 info->saddr.pan_id = wpan_dev->pan_id; 54 info->daddr.pan_id = info->saddr.pan_id; 55 56 if (!memcmp(daddr, ldev->broadcast, EUI64_ADDR_LEN)) { 57 info->daddr.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST); 58 info->daddr.mode = IEEE802154_ADDR_SHORT; 59 } else { 60 __le16 short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC); 61 62 n = neigh_lookup(&nd_tbl, &hdr->daddr, ldev); 63 if (n) { 64 llneigh = lowpan_802154_neigh(neighbour_priv(n)); 65 read_lock_bh(&n->lock); 66 short_addr = llneigh->short_addr; 67 read_unlock_bh(&n->lock); 68 } 69 70 if (llneigh && 71 lowpan_802154_is_valid_src_short_addr(short_addr)) { 72 info->daddr.short_addr = short_addr; 73 info->daddr.mode = IEEE802154_ADDR_SHORT; 74 } else { 75 info->daddr.mode = IEEE802154_ADDR_LONG; 76 ieee802154_be64_to_le64(&info->daddr.extended_addr, 77 daddr); 78 } 79 80 if (n) 81 neigh_release(n); 82 } 83 84 if (!saddr) { 85 if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr)) { 86 info->saddr.mode = IEEE802154_ADDR_SHORT; 87 info->saddr.short_addr = wpan_dev->short_addr; 88 } else { 89 info->saddr.mode = IEEE802154_ADDR_LONG; 90 info->saddr.extended_addr = wpan_dev->extended_addr; 91 } 92 } else { 93 info->saddr.mode = IEEE802154_ADDR_LONG; 94 ieee802154_be64_to_le64(&info->saddr.extended_addr, saddr); 95 } 96 97 return 0; 98 } 99 100 static struct sk_buff* 101 lowpan_alloc_frag(struct sk_buff *skb, int size, 102 const struct ieee802154_hdr *master_hdr, bool frag1) 103 { 104 struct net_device *wdev = lowpan_802154_dev(skb->dev)->wdev; 105 struct sk_buff *frag; 106 int rc; 107 108 frag = alloc_skb(wdev->needed_headroom + wdev->needed_tailroom + size, 109 GFP_ATOMIC); 110 111 if (likely(frag)) { 112 frag->dev = wdev; 113 frag->priority = skb->priority; 114 skb_reserve(frag, wdev->needed_headroom); 115 skb_reset_network_header(frag); 116 *mac_cb(frag) = *mac_cb(skb); 117 118 if (frag1) { 119 skb_put_data(frag, skb_mac_header(skb), skb->mac_len); 120 } else { 121 rc = wpan_dev_hard_header(frag, wdev, 122 &master_hdr->dest, 123 &master_hdr->source, size); 124 if (rc < 0) { 125 kfree_skb(frag); 126 return ERR_PTR(rc); 127 } 128 } 129 } else { 130 frag = ERR_PTR(-ENOMEM); 131 } 132 133 return frag; 134 } 135 136 static int 137 lowpan_xmit_fragment(struct sk_buff *skb, const struct ieee802154_hdr *wpan_hdr, 138 u8 *frag_hdr, int frag_hdrlen, 139 int offset, int len, bool frag1) 140 { 141 struct sk_buff *frag; 142 143 raw_dump_inline(__func__, " fragment header", frag_hdr, frag_hdrlen); 144 145 frag = lowpan_alloc_frag(skb, frag_hdrlen + len, wpan_hdr, frag1); 146 if (IS_ERR(frag)) 147 return PTR_ERR(frag); 148 149 skb_put_data(frag, frag_hdr, frag_hdrlen); 150 skb_put_data(frag, skb_network_header(skb) + offset, len); 151 152 raw_dump_table(__func__, " fragment dump", frag->data, frag->len); 153 154 return dev_queue_xmit(frag); 155 } 156 157 static int 158 lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *ldev, 159 const struct ieee802154_hdr *wpan_hdr, u16 dgram_size, 160 u16 dgram_offset) 161 { 162 __be16 frag_tag; 163 u8 frag_hdr[5]; 164 int frag_cap, frag_len, payload_cap, rc; 165 int skb_unprocessed, skb_offset; 166 167 frag_tag = htons(lowpan_802154_dev(ldev)->fragment_tag); 168 lowpan_802154_dev(ldev)->fragment_tag++; 169 170 frag_hdr[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x07); 171 frag_hdr[1] = dgram_size & 0xff; 172 memcpy(frag_hdr + 2, &frag_tag, sizeof(frag_tag)); 173 174 payload_cap = ieee802154_max_payload(wpan_hdr); 175 176 frag_len = round_down(payload_cap - LOWPAN_FRAG1_HEAD_SIZE - 177 skb_network_header_len(skb), 8); 178 179 skb_offset = skb_network_header_len(skb); 180 skb_unprocessed = skb->len - skb->mac_len - skb_offset; 181 182 rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr, 183 LOWPAN_FRAG1_HEAD_SIZE, 0, 184 frag_len + skb_network_header_len(skb), 185 true); 186 if (rc) { 187 pr_debug("%s unable to send FRAG1 packet (tag: %d)", 188 __func__, ntohs(frag_tag)); 189 goto err; 190 } 191 192 frag_hdr[0] &= ~LOWPAN_DISPATCH_FRAG1; 193 frag_hdr[0] |= LOWPAN_DISPATCH_FRAGN; 194 frag_cap = round_down(payload_cap - LOWPAN_FRAGN_HEAD_SIZE, 8); 195 196 do { 197 dgram_offset += frag_len; 198 skb_offset += frag_len; 199 skb_unprocessed -= frag_len; 200 frag_len = min(frag_cap, skb_unprocessed); 201 202 frag_hdr[4] = dgram_offset >> 3; 203 204 rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr, 205 LOWPAN_FRAGN_HEAD_SIZE, skb_offset, 206 frag_len, false); 207 if (rc) { 208 pr_debug("%s unable to send a FRAGN packet. (tag: %d, offset: %d)\n", 209 __func__, ntohs(frag_tag), skb_offset); 210 goto err; 211 } 212 } while (skb_unprocessed > frag_cap); 213 214 ldev->stats.tx_packets++; 215 ldev->stats.tx_bytes += dgram_size; 216 consume_skb(skb); 217 return NET_XMIT_SUCCESS; 218 219 err: 220 kfree_skb(skb); 221 return rc; 222 } 223 224 static int lowpan_header(struct sk_buff *skb, struct net_device *ldev, 225 u16 *dgram_size, u16 *dgram_offset) 226 { 227 struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr; 228 struct ieee802154_mac_cb *cb = mac_cb_init(skb); 229 struct lowpan_addr_info info; 230 231 memcpy(&info, lowpan_skb_priv(skb), sizeof(info)); 232 233 *dgram_size = skb->len; 234 lowpan_header_compress(skb, ldev, &info.daddr, &info.saddr); 235 /* dgram_offset = (saved bytes after compression) + lowpan header len */ 236 *dgram_offset = (*dgram_size - skb->len) + skb_network_header_len(skb); 237 238 cb->type = IEEE802154_FC_TYPE_DATA; 239 240 if (info.daddr.mode == IEEE802154_ADDR_SHORT && 241 ieee802154_is_broadcast_short_addr(info.daddr.short_addr)) 242 cb->ackreq = false; 243 else 244 cb->ackreq = wpan_dev->ackreq; 245 246 return wpan_dev_hard_header(skb, lowpan_802154_dev(ldev)->wdev, 247 &info.daddr, &info.saddr, 0); 248 } 249 250 netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev) 251 { 252 struct ieee802154_hdr wpan_hdr; 253 int max_single, ret; 254 u16 dgram_size, dgram_offset; 255 256 pr_debug("package xmit\n"); 257 258 WARN_ON_ONCE(skb->len > IPV6_MIN_MTU); 259 260 /* We must take a copy of the skb before we modify/replace the ipv6 261 * header as the header could be used elsewhere 262 */ 263 if (unlikely(skb_headroom(skb) < ldev->needed_headroom || 264 skb_tailroom(skb) < ldev->needed_tailroom)) { 265 struct sk_buff *nskb; 266 267 nskb = skb_copy_expand(skb, ldev->needed_headroom, 268 ldev->needed_tailroom, GFP_ATOMIC); 269 if (likely(nskb)) { 270 consume_skb(skb); 271 skb = nskb; 272 } else { 273 kfree_skb(skb); 274 return NET_XMIT_DROP; 275 } 276 } else { 277 skb = skb_unshare(skb, GFP_ATOMIC); 278 if (!skb) 279 return NET_XMIT_DROP; 280 } 281 282 ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset); 283 if (ret < 0) { 284 kfree_skb(skb); 285 return NET_XMIT_DROP; 286 } 287 288 if (ieee802154_hdr_peek(skb, &wpan_hdr) < 0) { 289 kfree_skb(skb); 290 return NET_XMIT_DROP; 291 } 292 293 max_single = ieee802154_max_payload(&wpan_hdr); 294 295 if (skb_tail_pointer(skb) - skb_network_header(skb) <= max_single) { 296 skb->dev = lowpan_802154_dev(ldev)->wdev; 297 ldev->stats.tx_packets++; 298 ldev->stats.tx_bytes += dgram_size; 299 return dev_queue_xmit(skb); 300 } else { 301 netdev_tx_t rc; 302 303 pr_debug("frame is too big, fragmentation is needed\n"); 304 rc = lowpan_xmit_fragmented(skb, ldev, &wpan_hdr, dgram_size, 305 dgram_offset); 306 307 return rc < 0 ? NET_XMIT_DROP : rc; 308 } 309 } 310