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 (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(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(p: daddr, q: 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(tbl: &nd_tbl, pkey: &hdr->daddr, dev: ldev); |
63 | if (n) { |
64 | llneigh = lowpan_802154_neigh(neigh_priv: 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(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(le64_dst: &info->daddr.extended_addr, |
77 | be64_src: daddr); |
78 | } |
79 | |
80 | if (n) |
81 | neigh_release(neigh: n); |
82 | } |
83 | |
84 | if (!saddr) { |
85 | if (lowpan_802154_is_valid_src_short_addr(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(le64_dst: &info->saddr.extended_addr, be64_src: 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(dev: skb->dev)->wdev; |
105 | struct sk_buff *frag; |
106 | int rc; |
107 | |
108 | frag = alloc_skb(size: 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(skb: frag, len: wdev->needed_headroom); |
115 | skb_reset_network_header(skb: frag); |
116 | *mac_cb(skb: frag) = *mac_cb(skb); |
117 | |
118 | if (frag1) { |
119 | skb_put_data(skb: frag, data: skb_mac_header(skb), len: skb->mac_len); |
120 | } else { |
121 | rc = wpan_dev_hard_header(skb: frag, dev: wdev, |
122 | daddr: &master_hdr->dest, |
123 | saddr: &master_hdr->source, len: size); |
124 | if (rc < 0) { |
125 | kfree_skb(skb: frag); |
126 | return ERR_PTR(error: rc); |
127 | } |
128 | } |
129 | } else { |
130 | frag = ERR_PTR(error: -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(caller: __func__, msg: " fragment header" , buf: frag_hdr, len: frag_hdrlen); |
144 | |
145 | frag = lowpan_alloc_frag(skb, size: frag_hdrlen + len, master_hdr: wpan_hdr, frag1); |
146 | if (IS_ERR(ptr: frag)) |
147 | return PTR_ERR(ptr: frag); |
148 | |
149 | skb_put_data(skb: frag, data: frag_hdr, len: frag_hdrlen); |
150 | skb_put_data(skb: frag, data: skb_network_header(skb) + offset, len); |
151 | |
152 | raw_dump_table(caller: __func__, msg: " fragment dump" , buf: frag->data, len: frag->len); |
153 | |
154 | return dev_queue_xmit(skb: 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(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(hdr: 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, offset: 0, |
184 | len: frag_len + skb_network_header_len(skb), |
185 | frag1: 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, offset: skb_offset, |
206 | len: frag_len, frag1: 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 (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(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, dev: ldev, daddr: &info.daddr, saddr: &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(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, dev: lowpan_802154_dev(dev: ldev)->wdev, |
247 | daddr: &info.daddr, saddr: &info.saddr, len: 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, newheadroom: ldev->needed_headroom, |
268 | newtailroom: 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_size, dgram_offset: &dgram_offset); |
283 | if (ret < 0) { |
284 | kfree_skb(skb); |
285 | return NET_XMIT_DROP; |
286 | } |
287 | |
288 | if (ieee802154_hdr_peek(skb, hdr: &wpan_hdr) < 0) { |
289 | kfree_skb(skb); |
290 | return NET_XMIT_DROP; |
291 | } |
292 | |
293 | max_single = ieee802154_max_payload(hdr: &wpan_hdr); |
294 | |
295 | if (skb_tail_pointer(skb) - skb_network_header(skb) <= max_single) { |
296 | skb->dev = lowpan_802154_dev(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: &wpan_hdr, dgram_size, |
305 | dgram_offset); |
306 | |
307 | return rc < 0 ? NET_XMIT_DROP : rc; |
308 | } |
309 | } |
310 | |