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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * INET An implementation of the TCP/IP protocol suite for the LINUX | |
4 | * operating system. INET is implemented using the BSD Socket | |
5 | * interface as the means of communication with the user level. | |
6 | * | |
7 | * The IP fragmentation functionality. | |
e905a9ed | 8 | * |
1da177e4 | 9 | * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG> |
113aa838 | 10 | * Alan Cox <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
11 | * |
12 | * Fixes: | |
13 | * Alan Cox : Split from ip.c , see ip_input.c for history. | |
14 | * David S. Miller : Begin massive cleanup... | |
15 | * Andi Kleen : Add sysctls. | |
16 | * xxxx : Overlapfrag bug. | |
17 | * Ultima : ip_expire() kernel panic. | |
18 | * Bill Hawes : Frag accounting and evictor fixes. | |
19 | * John McDonald : 0 length frag bug. | |
20 | * Alexey Kuznetsov: SMP races, threading, cleanup. | |
21 | * Patrick McHardy : LRU queue of frag heads for evictor. | |
22 | */ | |
23 | ||
afd46503 JP |
24 | #define pr_fmt(fmt) "IPv4: " fmt |
25 | ||
89cee8b1 | 26 | #include <linux/compiler.h> |
1da177e4 LT |
27 | #include <linux/module.h> |
28 | #include <linux/types.h> | |
29 | #include <linux/mm.h> | |
30 | #include <linux/jiffies.h> | |
31 | #include <linux/skbuff.h> | |
32 | #include <linux/list.h> | |
33 | #include <linux/ip.h> | |
34 | #include <linux/icmp.h> | |
35 | #include <linux/netdevice.h> | |
36 | #include <linux/jhash.h> | |
37 | #include <linux/random.h> | |
5a0e3ad6 | 38 | #include <linux/slab.h> |
e9017b55 SW |
39 | #include <net/route.h> |
40 | #include <net/dst.h> | |
1da177e4 LT |
41 | #include <net/sock.h> |
42 | #include <net/ip.h> | |
43 | #include <net/icmp.h> | |
44 | #include <net/checksum.h> | |
89cee8b1 | 45 | #include <net/inetpeer.h> |
5ab11c98 | 46 | #include <net/inet_frag.h> |
1da177e4 LT |
47 | #include <linux/tcp.h> |
48 | #include <linux/udp.h> | |
49 | #include <linux/inet.h> | |
50 | #include <linux/netfilter_ipv4.h> | |
6623e3b2 | 51 | #include <net/inet_ecn.h> |
385add90 | 52 | #include <net/l3mdev.h> |
1da177e4 LT |
53 | |
54 | /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6 | |
55 | * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c | |
56 | * as well. Or notify me, at least. --ANK | |
57 | */ | |
d4ad4d22 | 58 | static const char ip_frag_cache_name[] = "ip4-frags"; |
89cee8b1 | 59 | |
1da177e4 LT |
60 | struct ipfrag_skb_cb |
61 | { | |
62 | struct inet_skb_parm h; | |
63 | int offset; | |
64 | }; | |
65 | ||
fd3f8c4c | 66 | #define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb)) |
1da177e4 LT |
67 | |
68 | /* Describe an entry in the "incomplete datagrams" queue. */ | |
69 | struct ipq { | |
5ab11c98 PE |
70 | struct inet_frag_queue q; |
71 | ||
6623e3b2 | 72 | u8 ecn; /* RFC3168 support */ |
d6b915e2 | 73 | u16 max_df_size; /* largest frag with DF set seen */ |
89cee8b1 HX |
74 | int iif; |
75 | unsigned int rid; | |
76 | struct inet_peer *peer; | |
1da177e4 LT |
77 | }; |
78 | ||
aa1f731e | 79 | static u8 ip4_frag_ecn(u8 tos) |
6623e3b2 | 80 | { |
5173cc05 | 81 | return 1 << (tos & INET_ECN_MASK); |
6623e3b2 ED |
82 | } |
83 | ||
7eb95156 | 84 | static struct inet_frags ip4_frags; |
1da177e4 | 85 | |
1706d587 HX |
86 | static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, |
87 | struct net_device *dev); | |
88 | ||
abd6523d | 89 | |
36c77782 | 90 | static void ip4_frag_init(struct inet_frag_queue *q, const void *a) |
c6fda282 PE |
91 | { |
92 | struct ipq *qp = container_of(q, struct ipq, q); | |
54db0cc2 G |
93 | struct netns_ipv4 *ipv4 = container_of(q->net, struct netns_ipv4, |
94 | frags); | |
95 | struct net *net = container_of(ipv4, struct net, ipv4); | |
96 | ||
648700f7 | 97 | const struct frag_v4_compare_key *key = a; |
c6fda282 | 98 | |
648700f7 ED |
99 | q->key.v4 = *key; |
100 | qp->ecn = 0; | |
0fbf4cb2 | 101 | qp->peer = q->net->max_dist ? |
648700f7 | 102 | inet_getpeer_v4(net->ipv4.peers, key->saddr, key->vif, 1) : |
192132b9 | 103 | NULL; |
c6fda282 PE |
104 | } |
105 | ||
aa1f731e | 106 | static void ip4_frag_free(struct inet_frag_queue *q) |
1da177e4 | 107 | { |
1e4b8287 PE |
108 | struct ipq *qp; |
109 | ||
110 | qp = container_of(q, struct ipq, q); | |
111 | if (qp->peer) | |
112 | inet_putpeer(qp->peer); | |
1da177e4 LT |
113 | } |
114 | ||
1da177e4 LT |
115 | |
116 | /* Destruction primitives. */ | |
117 | ||
aa1f731e | 118 | static void ipq_put(struct ipq *ipq) |
1da177e4 | 119 | { |
093ba729 | 120 | inet_frag_put(&ipq->q); |
1da177e4 LT |
121 | } |
122 | ||
123 | /* Kill ipq entry. It is not destroyed immediately, | |
124 | * because caller (and someone more) holds reference count. | |
125 | */ | |
126 | static void ipq_kill(struct ipq *ipq) | |
127 | { | |
093ba729 | 128 | inet_frag_kill(&ipq->q); |
1da177e4 LT |
129 | } |
130 | ||
5cf42280 AZ |
131 | static bool frag_expire_skip_icmp(u32 user) |
132 | { | |
133 | return user == IP_DEFRAG_AF_PACKET || | |
134 | ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_IN, | |
8bc04864 AZ |
135 | __IP_DEFRAG_CONNTRACK_IN_END) || |
136 | ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_BRIDGE_IN, | |
137 | __IP_DEFRAG_CONNTRACK_BRIDGE_IN); | |
5cf42280 AZ |
138 | } |
139 | ||
1da177e4 LT |
140 | /* |
141 | * Oops, a fragment queue timed out. Kill it and send an ICMP reply. | |
142 | */ | |
78802011 | 143 | static void ip_expire(struct timer_list *t) |
1da177e4 | 144 | { |
78802011 | 145 | struct inet_frag_queue *frag = from_timer(frag, t, timer); |
e521db9d | 146 | struct ipq *qp; |
84a3aa00 | 147 | struct net *net; |
e521db9d | 148 | |
78802011 | 149 | qp = container_of(frag, struct ipq, q); |
84a3aa00 | 150 | net = container_of(qp->q.net, struct net, ipv4.frags); |
1da177e4 | 151 | |
ec4fbd64 | 152 | rcu_read_lock(); |
5ab11c98 | 153 | spin_lock(&qp->q.lock); |
1da177e4 | 154 | |
06aa8b8a | 155 | if (qp->q.flags & INET_FRAG_COMPLETE) |
1da177e4 LT |
156 | goto out; |
157 | ||
158 | ipq_kill(qp); | |
b45386ef | 159 | __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); |
1da177e4 | 160 | |
caaecdd3 | 161 | if (!inet_frag_evicting(&qp->q)) { |
ec4fbd64 | 162 | struct sk_buff *clone, *head = qp->q.fragments; |
64f3b9e2 ED |
163 | const struct iphdr *iph; |
164 | int err; | |
cb84663e | 165 | |
b45386ef | 166 | __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT); |
2e404f63 NA |
167 | |
168 | if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !qp->q.fragments) | |
169 | goto out; | |
170 | ||
69df9d59 | 171 | head->dev = dev_get_by_index_rcu(net, qp->iif); |
e9017b55 | 172 | if (!head->dev) |
ec4fbd64 ED |
173 | goto out; |
174 | ||
e9017b55 | 175 | |
97599dc7 | 176 | /* skb has no dst, perform route lookup again */ |
64f3b9e2 | 177 | iph = ip_hdr(head); |
c6cffba4 DM |
178 | err = ip_route_input_noref(head, iph->daddr, iph->saddr, |
179 | iph->tos, head->dev); | |
64f3b9e2 | 180 | if (err) |
ec4fbd64 | 181 | goto out; |
64f3b9e2 | 182 | |
2e404f63 | 183 | /* Only an end host needs to send an ICMP |
64f3b9e2 | 184 | * "Fragment Reassembly Timeout" message, per RFC792. |
e9017b55 | 185 | */ |
648700f7 | 186 | if (frag_expire_skip_icmp(qp->q.key.v4.user) && |
5cf42280 | 187 | (skb_rtable(head)->rt_type != RTN_LOCAL)) |
ec4fbd64 ED |
188 | goto out; |
189 | ||
190 | clone = skb_clone(head, GFP_ATOMIC); | |
64f3b9e2 | 191 | |
e9017b55 | 192 | /* Send an ICMP "Fragment Reassembly Timeout" message. */ |
ec4fbd64 ED |
193 | if (clone) { |
194 | spin_unlock(&qp->q.lock); | |
195 | icmp_send(clone, ICMP_TIME_EXCEEDED, | |
196 | ICMP_EXC_FRAGTIME, 0); | |
197 | consume_skb(clone); | |
198 | goto out_rcu_unlock; | |
199 | } | |
d1c9ae6d | 200 | } |
1da177e4 | 201 | out: |
5ab11c98 | 202 | spin_unlock(&qp->q.lock); |
ec4fbd64 ED |
203 | out_rcu_unlock: |
204 | rcu_read_unlock(); | |
4b6cb5d8 | 205 | ipq_put(qp); |
1da177e4 LT |
206 | } |
207 | ||
abd6523d PE |
208 | /* Find the correct entry in the "incomplete datagrams" queue for |
209 | * this IP datagram, and create new one, if nothing is found. | |
210 | */ | |
9972f134 DA |
211 | static struct ipq *ip_find(struct net *net, struct iphdr *iph, |
212 | u32 user, int vif) | |
1da177e4 | 213 | { |
648700f7 ED |
214 | struct frag_v4_compare_key key = { |
215 | .saddr = iph->saddr, | |
216 | .daddr = iph->daddr, | |
217 | .user = user, | |
218 | .vif = vif, | |
219 | .id = iph->id, | |
220 | .protocol = iph->protocol, | |
221 | }; | |
c6fda282 | 222 | struct inet_frag_queue *q; |
9a375803 | 223 | |
648700f7 | 224 | q = inet_frag_find(&net->ipv4.frags, &key); |
5a3da1fe HFS |
225 | if (IS_ERR_OR_NULL(q)) { |
226 | inet_frag_maybe_warn_overflow(q, pr_fmt()); | |
227 | return NULL; | |
228 | } | |
c6fda282 | 229 | return container_of(q, struct ipq, q); |
1da177e4 LT |
230 | } |
231 | ||
89cee8b1 | 232 | /* Is the fragment too far ahead to be part of ipq? */ |
aa1f731e | 233 | static int ip_frag_too_far(struct ipq *qp) |
89cee8b1 HX |
234 | { |
235 | struct inet_peer *peer = qp->peer; | |
0fbf4cb2 | 236 | unsigned int max = qp->q.net->max_dist; |
89cee8b1 HX |
237 | unsigned int start, end; |
238 | ||
239 | int rc; | |
240 | ||
241 | if (!peer || !max) | |
242 | return 0; | |
243 | ||
244 | start = qp->rid; | |
245 | end = atomic_inc_return(&peer->rid); | |
246 | qp->rid = end; | |
247 | ||
5ab11c98 | 248 | rc = qp->q.fragments && (end - start) > max; |
89cee8b1 HX |
249 | |
250 | if (rc) { | |
7c73a6fa PE |
251 | struct net *net; |
252 | ||
253 | net = container_of(qp->q.net, struct net, ipv4.frags); | |
b45386ef | 254 | __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); |
89cee8b1 HX |
255 | } |
256 | ||
257 | return rc; | |
258 | } | |
259 | ||
260 | static int ip_frag_reinit(struct ipq *qp) | |
261 | { | |
262 | struct sk_buff *fp; | |
d433673e | 263 | unsigned int sum_truesize = 0; |
89cee8b1 | 264 | |
b2fd5321 | 265 | if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) { |
edcb6918 | 266 | refcount_inc(&qp->q.refcnt); |
89cee8b1 HX |
267 | return -ETIMEDOUT; |
268 | } | |
269 | ||
5ab11c98 | 270 | fp = qp->q.fragments; |
89cee8b1 HX |
271 | do { |
272 | struct sk_buff *xp = fp->next; | |
d433673e JDB |
273 | |
274 | sum_truesize += fp->truesize; | |
275 | kfree_skb(fp); | |
89cee8b1 HX |
276 | fp = xp; |
277 | } while (fp); | |
0e60d245 | 278 | sub_frag_mem_limit(qp->q.net, sum_truesize); |
89cee8b1 | 279 | |
06aa8b8a | 280 | qp->q.flags = 0; |
5ab11c98 PE |
281 | qp->q.len = 0; |
282 | qp->q.meat = 0; | |
283 | qp->q.fragments = NULL; | |
d6bebca9 | 284 | qp->q.fragments_tail = NULL; |
89cee8b1 | 285 | qp->iif = 0; |
6623e3b2 | 286 | qp->ecn = 0; |
89cee8b1 HX |
287 | |
288 | return 0; | |
289 | } | |
290 | ||
1da177e4 | 291 | /* Add new segment to existing queue. */ |
1706d587 | 292 | static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) |
1da177e4 LT |
293 | { |
294 | struct sk_buff *prev, *next; | |
1706d587 | 295 | struct net_device *dev; |
d6b915e2 | 296 | unsigned int fragsize; |
1da177e4 LT |
297 | int flags, offset; |
298 | int ihl, end; | |
1706d587 | 299 | int err = -ENOENT; |
6623e3b2 | 300 | u8 ecn; |
1da177e4 | 301 | |
06aa8b8a | 302 | if (qp->q.flags & INET_FRAG_COMPLETE) |
1da177e4 LT |
303 | goto err; |
304 | ||
89cee8b1 | 305 | if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && |
1706d587 HX |
306 | unlikely(ip_frag_too_far(qp)) && |
307 | unlikely(err = ip_frag_reinit(qp))) { | |
89cee8b1 HX |
308 | ipq_kill(qp); |
309 | goto err; | |
310 | } | |
311 | ||
6623e3b2 | 312 | ecn = ip4_frag_ecn(ip_hdr(skb)->tos); |
eddc9ec5 | 313 | offset = ntohs(ip_hdr(skb)->frag_off); |
1da177e4 LT |
314 | flags = offset & ~IP_OFFSET; |
315 | offset &= IP_OFFSET; | |
316 | offset <<= 3; /* offset is in 8-byte chunks */ | |
c9bdd4b5 | 317 | ihl = ip_hdrlen(skb); |
1da177e4 LT |
318 | |
319 | /* Determine the position of this fragment. */ | |
0848f642 | 320 | end = offset + skb->len - skb_network_offset(skb) - ihl; |
1706d587 | 321 | err = -EINVAL; |
1da177e4 LT |
322 | |
323 | /* Is this the final fragment? */ | |
324 | if ((flags & IP_MF) == 0) { | |
325 | /* If we already have some bits beyond end | |
42b2aa86 | 326 | * or have different end, the segment is corrupted. |
1da177e4 | 327 | */ |
5ab11c98 | 328 | if (end < qp->q.len || |
06aa8b8a | 329 | ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len)) |
1da177e4 | 330 | goto err; |
06aa8b8a | 331 | qp->q.flags |= INET_FRAG_LAST_IN; |
5ab11c98 | 332 | qp->q.len = end; |
1da177e4 LT |
333 | } else { |
334 | if (end&7) { | |
335 | end &= ~7; | |
336 | if (skb->ip_summed != CHECKSUM_UNNECESSARY) | |
337 | skb->ip_summed = CHECKSUM_NONE; | |
338 | } | |
5ab11c98 | 339 | if (end > qp->q.len) { |
1da177e4 | 340 | /* Some bits beyond end -> corruption. */ |
06aa8b8a | 341 | if (qp->q.flags & INET_FRAG_LAST_IN) |
1da177e4 | 342 | goto err; |
5ab11c98 | 343 | qp->q.len = end; |
1da177e4 LT |
344 | } |
345 | } | |
346 | if (end == offset) | |
347 | goto err; | |
348 | ||
1706d587 | 349 | err = -ENOMEM; |
0848f642 | 350 | if (!pskb_pull(skb, skb_network_offset(skb) + ihl)) |
1da177e4 | 351 | goto err; |
1706d587 HX |
352 | |
353 | err = pskb_trim_rcsum(skb, end - offset); | |
354 | if (err) | |
1da177e4 LT |
355 | goto err; |
356 | ||
357 | /* Find out which fragments are in front and at the back of us | |
358 | * in the chain of fragments so far. We must know where to put | |
359 | * this fragment, right? | |
360 | */ | |
d6bebca9 CG |
361 | prev = qp->q.fragments_tail; |
362 | if (!prev || FRAG_CB(prev)->offset < offset) { | |
363 | next = NULL; | |
364 | goto found; | |
365 | } | |
1da177e4 | 366 | prev = NULL; |
5ab11c98 | 367 | for (next = qp->q.fragments; next != NULL; next = next->next) { |
1da177e4 LT |
368 | if (FRAG_CB(next)->offset >= offset) |
369 | break; /* bingo! */ | |
370 | prev = next; | |
371 | } | |
372 | ||
d6bebca9 | 373 | found: |
1da177e4 LT |
374 | /* We found where to put this one. Check for overlap with |
375 | * preceding fragment, and, if needed, align things so that | |
376 | * any overlaps are eliminated. | |
377 | */ | |
378 | if (prev) { | |
379 | int i = (FRAG_CB(prev)->offset + prev->len) - offset; | |
380 | ||
381 | if (i > 0) { | |
382 | offset += i; | |
1706d587 | 383 | err = -EINVAL; |
1da177e4 LT |
384 | if (end <= offset) |
385 | goto err; | |
1706d587 | 386 | err = -ENOMEM; |
1da177e4 LT |
387 | if (!pskb_pull(skb, i)) |
388 | goto err; | |
389 | if (skb->ip_summed != CHECKSUM_UNNECESSARY) | |
390 | skb->ip_summed = CHECKSUM_NONE; | |
391 | } | |
392 | } | |
393 | ||
1706d587 HX |
394 | err = -ENOMEM; |
395 | ||
1da177e4 LT |
396 | while (next && FRAG_CB(next)->offset < end) { |
397 | int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */ | |
398 | ||
399 | if (i < next->len) { | |
400 | /* Eat head of the next overlapped fragment | |
401 | * and leave the loop. The next ones cannot overlap. | |
402 | */ | |
403 | if (!pskb_pull(next, i)) | |
404 | goto err; | |
405 | FRAG_CB(next)->offset += i; | |
5ab11c98 | 406 | qp->q.meat -= i; |
1da177e4 LT |
407 | if (next->ip_summed != CHECKSUM_UNNECESSARY) |
408 | next->ip_summed = CHECKSUM_NONE; | |
409 | break; | |
410 | } else { | |
411 | struct sk_buff *free_it = next; | |
412 | ||
47c6bf77 | 413 | /* Old fragment is completely overridden with |
1da177e4 LT |
414 | * new one drop it. |
415 | */ | |
416 | next = next->next; | |
417 | ||
418 | if (prev) | |
419 | prev->next = next; | |
420 | else | |
5ab11c98 | 421 | qp->q.fragments = next; |
1da177e4 | 422 | |
5ab11c98 | 423 | qp->q.meat -= free_it->len; |
0e60d245 | 424 | sub_frag_mem_limit(qp->q.net, free_it->truesize); |
d433673e | 425 | kfree_skb(free_it); |
1da177e4 LT |
426 | } |
427 | } | |
428 | ||
429 | FRAG_CB(skb)->offset = offset; | |
430 | ||
431 | /* Insert this fragment in the chain of fragments. */ | |
432 | skb->next = next; | |
d6bebca9 CG |
433 | if (!next) |
434 | qp->q.fragments_tail = skb; | |
1da177e4 LT |
435 | if (prev) |
436 | prev->next = skb; | |
437 | else | |
5ab11c98 | 438 | qp->q.fragments = skb; |
1da177e4 | 439 | |
1706d587 HX |
440 | dev = skb->dev; |
441 | if (dev) { | |
442 | qp->iif = dev->ifindex; | |
443 | skb->dev = NULL; | |
444 | } | |
5ab11c98 PE |
445 | qp->q.stamp = skb->tstamp; |
446 | qp->q.meat += skb->len; | |
6623e3b2 | 447 | qp->ecn |= ecn; |
0e60d245 | 448 | add_frag_mem_limit(qp->q.net, skb->truesize); |
1da177e4 | 449 | if (offset == 0) |
06aa8b8a | 450 | qp->q.flags |= INET_FRAG_FIRST_IN; |
1da177e4 | 451 | |
d6b915e2 FW |
452 | fragsize = skb->len + ihl; |
453 | ||
454 | if (fragsize > qp->q.max_size) | |
455 | qp->q.max_size = fragsize; | |
456 | ||
5f2d04f1 | 457 | if (ip_hdr(skb)->frag_off & htons(IP_DF) && |
d6b915e2 FW |
458 | fragsize > qp->max_df_size) |
459 | qp->max_df_size = fragsize; | |
5f2d04f1 | 460 | |
06aa8b8a | 461 | if (qp->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && |
97599dc7 ED |
462 | qp->q.meat == qp->q.len) { |
463 | unsigned long orefdst = skb->_skb_refdst; | |
1706d587 | 464 | |
97599dc7 ED |
465 | skb->_skb_refdst = 0UL; |
466 | err = ip_frag_reasm(qp, prev, dev); | |
467 | skb->_skb_refdst = orefdst; | |
468 | return err; | |
469 | } | |
470 | ||
471 | skb_dst_drop(skb); | |
1706d587 | 472 | return -EINPROGRESS; |
1da177e4 LT |
473 | |
474 | err: | |
475 | kfree_skb(skb); | |
1706d587 | 476 | return err; |
1da177e4 LT |
477 | } |
478 | ||
479 | ||
480 | /* Build a new IP datagram from all its fragments. */ | |
481 | ||
1706d587 HX |
482 | static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, |
483 | struct net_device *dev) | |
1da177e4 | 484 | { |
2bad35b7 | 485 | struct net *net = container_of(qp->q.net, struct net, ipv4.frags); |
1da177e4 | 486 | struct iphdr *iph; |
5ab11c98 | 487 | struct sk_buff *fp, *head = qp->q.fragments; |
1da177e4 LT |
488 | int len; |
489 | int ihlen; | |
1706d587 | 490 | int err; |
5173cc05 | 491 | u8 ecn; |
1da177e4 LT |
492 | |
493 | ipq_kill(qp); | |
494 | ||
be991971 | 495 | ecn = ip_frag_ecn_table[qp->ecn]; |
5173cc05 ED |
496 | if (unlikely(ecn == 0xff)) { |
497 | err = -EINVAL; | |
498 | goto out_fail; | |
499 | } | |
1706d587 HX |
500 | /* Make the one we just received the head. */ |
501 | if (prev) { | |
502 | head = prev->next; | |
503 | fp = skb_clone(head, GFP_ATOMIC); | |
1706d587 HX |
504 | if (!fp) |
505 | goto out_nomem; | |
506 | ||
507 | fp->next = head->next; | |
d6bebca9 CG |
508 | if (!fp->next) |
509 | qp->q.fragments_tail = fp; | |
1706d587 HX |
510 | prev->next = fp; |
511 | ||
5ab11c98 PE |
512 | skb_morph(head, qp->q.fragments); |
513 | head->next = qp->q.fragments->next; | |
1706d587 | 514 | |
cbf8f7bb | 515 | consume_skb(qp->q.fragments); |
5ab11c98 | 516 | qp->q.fragments = head; |
1706d587 HX |
517 | } |
518 | ||
51456b29 | 519 | WARN_ON(!head); |
547b792c | 520 | WARN_ON(FRAG_CB(head)->offset != 0); |
1da177e4 LT |
521 | |
522 | /* Allocate a new buffer for the datagram. */ | |
c9bdd4b5 | 523 | ihlen = ip_hdrlen(head); |
5ab11c98 | 524 | len = ihlen + qp->q.len; |
1da177e4 | 525 | |
1706d587 | 526 | err = -E2BIG; |
132adf54 | 527 | if (len > 65535) |
1da177e4 LT |
528 | goto out_oversize; |
529 | ||
530 | /* Head of list must not be cloned. */ | |
14bbd6a5 | 531 | if (skb_unclone(head, GFP_ATOMIC)) |
1da177e4 LT |
532 | goto out_nomem; |
533 | ||
534 | /* If the first fragment is fragmented itself, we split | |
535 | * it to two chunks: the first with data and paged part | |
536 | * and the second, holding only fragments. */ | |
21dc3301 | 537 | if (skb_has_frag_list(head)) { |
1da177e4 LT |
538 | struct sk_buff *clone; |
539 | int i, plen = 0; | |
540 | ||
51456b29 IM |
541 | clone = alloc_skb(0, GFP_ATOMIC); |
542 | if (!clone) | |
1da177e4 LT |
543 | goto out_nomem; |
544 | clone->next = head->next; | |
545 | head->next = clone; | |
546 | skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; | |
d7fcf1a5 | 547 | skb_frag_list_init(head); |
9e903e08 ED |
548 | for (i = 0; i < skb_shinfo(head)->nr_frags; i++) |
549 | plen += skb_frag_size(&skb_shinfo(head)->frags[i]); | |
1da177e4 LT |
550 | clone->len = clone->data_len = head->data_len - plen; |
551 | head->data_len -= clone->len; | |
552 | head->len -= clone->len; | |
553 | clone->csum = 0; | |
554 | clone->ip_summed = head->ip_summed; | |
0e60d245 | 555 | add_frag_mem_limit(qp->q.net, clone->truesize); |
1da177e4 LT |
556 | } |
557 | ||
14fe22e3 | 558 | skb_shinfo(head)->frag_list = head->next; |
d56f90a7 | 559 | skb_push(head, head->data - skb_network_header(head)); |
1da177e4 | 560 | |
14fe22e3 FW |
561 | for (fp=head->next; fp; fp = fp->next) { |
562 | head->data_len += fp->len; | |
563 | head->len += fp->len; | |
1da177e4 LT |
564 | if (head->ip_summed != fp->ip_summed) |
565 | head->ip_summed = CHECKSUM_NONE; | |
84fa7933 | 566 | else if (head->ip_summed == CHECKSUM_COMPLETE) |
1da177e4 | 567 | head->csum = csum_add(head->csum, fp->csum); |
14fe22e3 | 568 | head->truesize += fp->truesize; |
1da177e4 | 569 | } |
5510b3c2 | 570 | sub_frag_mem_limit(qp->q.net, head->truesize); |
1da177e4 LT |
571 | |
572 | head->next = NULL; | |
573 | head->dev = dev; | |
5ab11c98 | 574 | head->tstamp = qp->q.stamp; |
d6b915e2 | 575 | IPCB(head)->frag_max_size = max(qp->max_df_size, qp->q.max_size); |
1da177e4 | 576 | |
eddc9ec5 | 577 | iph = ip_hdr(head); |
1da177e4 | 578 | iph->tot_len = htons(len); |
5173cc05 | 579 | iph->tos |= ecn; |
d6b915e2 FW |
580 | |
581 | /* When we set IP_DF on a refragmented skb we must also force a | |
582 | * call to ip_fragment to avoid forwarding a DF-skb of size s while | |
583 | * original sender only sent fragments of size f (where f < s). | |
584 | * | |
585 | * We only set DF/IPSKB_FRAG_PMTU if such DF fragment was the largest | |
586 | * frag seen to avoid sending tiny DF-fragments in case skb was built | |
587 | * from one very small df-fragment and one large non-df frag. | |
588 | */ | |
589 | if (qp->max_df_size == qp->q.max_size) { | |
590 | IPCB(head)->flags |= IPSKB_FRAG_PMTU; | |
591 | iph->frag_off = htons(IP_DF); | |
592 | } else { | |
593 | iph->frag_off = 0; | |
594 | } | |
595 | ||
0848f642 EHJ |
596 | ip_send_check(iph); |
597 | ||
b45386ef | 598 | __IP_INC_STATS(net, IPSTATS_MIB_REASMOKS); |
5ab11c98 | 599 | qp->q.fragments = NULL; |
d6bebca9 | 600 | qp->q.fragments_tail = NULL; |
1706d587 | 601 | return 0; |
1da177e4 LT |
602 | |
603 | out_nomem: | |
ba7a46f1 | 604 | net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp); |
45542479 | 605 | err = -ENOMEM; |
1da177e4 LT |
606 | goto out_fail; |
607 | out_oversize: | |
648700f7 | 608 | net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->q.key.v4.saddr); |
1da177e4 | 609 | out_fail: |
b45386ef | 610 | __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); |
1706d587 | 611 | return err; |
1da177e4 LT |
612 | } |
613 | ||
614 | /* Process an incoming IP datagram fragment. */ | |
19bcf9f2 | 615 | int ip_defrag(struct net *net, struct sk_buff *skb, u32 user) |
1da177e4 | 616 | { |
9972f134 | 617 | struct net_device *dev = skb->dev ? : skb_dst(skb)->dev; |
385add90 | 618 | int vif = l3mdev_master_ifindex_rcu(dev); |
1da177e4 | 619 | struct ipq *qp; |
e905a9ed | 620 | |
b45386ef | 621 | __IP_INC_STATS(net, IPSTATS_MIB_REASMREQDS); |
8282f274 | 622 | skb_orphan(skb); |
1da177e4 | 623 | |
1da177e4 | 624 | /* Lookup (or create) queue header */ |
9972f134 | 625 | qp = ip_find(net, ip_hdr(skb), user, vif); |
00db4124 | 626 | if (qp) { |
1706d587 | 627 | int ret; |
1da177e4 | 628 | |
5ab11c98 | 629 | spin_lock(&qp->q.lock); |
1da177e4 | 630 | |
1706d587 | 631 | ret = ip_frag_queue(qp, skb); |
1da177e4 | 632 | |
5ab11c98 | 633 | spin_unlock(&qp->q.lock); |
4b6cb5d8 | 634 | ipq_put(qp); |
776c729e | 635 | return ret; |
1da177e4 LT |
636 | } |
637 | ||
b45386ef | 638 | __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); |
1da177e4 | 639 | kfree_skb(skb); |
776c729e | 640 | return -ENOMEM; |
1da177e4 | 641 | } |
4bc2f18b | 642 | EXPORT_SYMBOL(ip_defrag); |
1da177e4 | 643 | |
19bcf9f2 | 644 | struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user) |
bc416d97 | 645 | { |
1bf3751e | 646 | struct iphdr iph; |
3e32e733 | 647 | int netoff; |
bc416d97 ED |
648 | u32 len; |
649 | ||
650 | if (skb->protocol != htons(ETH_P_IP)) | |
651 | return skb; | |
652 | ||
3e32e733 AD |
653 | netoff = skb_network_offset(skb); |
654 | ||
655 | if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0) | |
bc416d97 ED |
656 | return skb; |
657 | ||
1bf3751e | 658 | if (iph.ihl < 5 || iph.version != 4) |
bc416d97 | 659 | return skb; |
1bf3751e JB |
660 | |
661 | len = ntohs(iph.tot_len); | |
3e32e733 | 662 | if (skb->len < netoff + len || len < (iph.ihl * 4)) |
bc416d97 ED |
663 | return skb; |
664 | ||
1bf3751e | 665 | if (ip_is_fragment(&iph)) { |
bc416d97 ED |
666 | skb = skb_share_check(skb, GFP_ATOMIC); |
667 | if (skb) { | |
3e32e733 | 668 | if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) |
1bf3751e | 669 | return skb; |
3e32e733 | 670 | if (pskb_trim_rcsum(skb, netoff + len)) |
bc416d97 ED |
671 | return skb; |
672 | memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); | |
19bcf9f2 | 673 | if (ip_defrag(net, skb, user)) |
bc416d97 | 674 | return NULL; |
7539fadc | 675 | skb_clear_hash(skb); |
bc416d97 ED |
676 | } |
677 | } | |
678 | return skb; | |
679 | } | |
680 | EXPORT_SYMBOL(ip_check_defrag); | |
681 | ||
8d8354d2 PE |
682 | #ifdef CONFIG_SYSCTL |
683 | static int zero; | |
684 | ||
0a64b4b8 | 685 | static struct ctl_table ip4_frags_ns_ctl_table[] = { |
8d8354d2 | 686 | { |
8d8354d2 | 687 | .procname = "ipfrag_high_thresh", |
e31e0bdc | 688 | .data = &init_net.ipv4.frags.high_thresh, |
8d8354d2 PE |
689 | .maxlen = sizeof(int), |
690 | .mode = 0644, | |
1bab4c75 NA |
691 | .proc_handler = proc_dointvec_minmax, |
692 | .extra1 = &init_net.ipv4.frags.low_thresh | |
8d8354d2 PE |
693 | }, |
694 | { | |
8d8354d2 | 695 | .procname = "ipfrag_low_thresh", |
e31e0bdc | 696 | .data = &init_net.ipv4.frags.low_thresh, |
8d8354d2 PE |
697 | .maxlen = sizeof(int), |
698 | .mode = 0644, | |
1bab4c75 NA |
699 | .proc_handler = proc_dointvec_minmax, |
700 | .extra1 = &zero, | |
701 | .extra2 = &init_net.ipv4.frags.high_thresh | |
8d8354d2 PE |
702 | }, |
703 | { | |
8d8354d2 | 704 | .procname = "ipfrag_time", |
b2fd5321 | 705 | .data = &init_net.ipv4.frags.timeout, |
8d8354d2 PE |
706 | .maxlen = sizeof(int), |
707 | .mode = 0644, | |
6d9f239a | 708 | .proc_handler = proc_dointvec_jiffies, |
8d8354d2 | 709 | }, |
0fbf4cb2 NB |
710 | { |
711 | .procname = "ipfrag_max_dist", | |
712 | .data = &init_net.ipv4.frags.max_dist, | |
713 | .maxlen = sizeof(int), | |
714 | .mode = 0644, | |
715 | .proc_handler = proc_dointvec_minmax, | |
716 | .extra1 = &zero | |
717 | }, | |
7d291ebb PE |
718 | { } |
719 | }; | |
720 | ||
e3a57d18 FW |
721 | /* secret interval has been deprecated */ |
722 | static int ip4_frags_secret_interval_unused; | |
7d291ebb | 723 | static struct ctl_table ip4_frags_ctl_table[] = { |
8d8354d2 | 724 | { |
8d8354d2 | 725 | .procname = "ipfrag_secret_interval", |
e3a57d18 | 726 | .data = &ip4_frags_secret_interval_unused, |
8d8354d2 PE |
727 | .maxlen = sizeof(int), |
728 | .mode = 0644, | |
6d9f239a | 729 | .proc_handler = proc_dointvec_jiffies, |
8d8354d2 | 730 | }, |
8d8354d2 PE |
731 | { } |
732 | }; | |
733 | ||
2c8c1e72 | 734 | static int __net_init ip4_frags_ns_ctl_register(struct net *net) |
8d8354d2 | 735 | { |
e4a2d5c2 | 736 | struct ctl_table *table; |
8d8354d2 PE |
737 | struct ctl_table_header *hdr; |
738 | ||
0a64b4b8 | 739 | table = ip4_frags_ns_ctl_table; |
09ad9bc7 | 740 | if (!net_eq(net, &init_net)) { |
0a64b4b8 | 741 | table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL); |
51456b29 | 742 | if (!table) |
e4a2d5c2 PE |
743 | goto err_alloc; |
744 | ||
e31e0bdc | 745 | table[0].data = &net->ipv4.frags.high_thresh; |
1bab4c75 NA |
746 | table[0].extra1 = &net->ipv4.frags.low_thresh; |
747 | table[0].extra2 = &init_net.ipv4.frags.high_thresh; | |
e31e0bdc | 748 | table[1].data = &net->ipv4.frags.low_thresh; |
1bab4c75 | 749 | table[1].extra2 = &net->ipv4.frags.high_thresh; |
b2fd5321 | 750 | table[2].data = &net->ipv4.frags.timeout; |
0fbf4cb2 | 751 | table[3].data = &net->ipv4.frags.max_dist; |
e4a2d5c2 PE |
752 | } |
753 | ||
ec8f23ce | 754 | hdr = register_net_sysctl(net, "net/ipv4", table); |
51456b29 | 755 | if (!hdr) |
e4a2d5c2 PE |
756 | goto err_reg; |
757 | ||
758 | net->ipv4.frags_hdr = hdr; | |
759 | return 0; | |
760 | ||
761 | err_reg: | |
09ad9bc7 | 762 | if (!net_eq(net, &init_net)) |
e4a2d5c2 PE |
763 | kfree(table); |
764 | err_alloc: | |
765 | return -ENOMEM; | |
766 | } | |
767 | ||
2c8c1e72 | 768 | static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net) |
e4a2d5c2 PE |
769 | { |
770 | struct ctl_table *table; | |
771 | ||
772 | table = net->ipv4.frags_hdr->ctl_table_arg; | |
773 | unregister_net_sysctl_table(net->ipv4.frags_hdr); | |
774 | kfree(table); | |
8d8354d2 | 775 | } |
7d291ebb | 776 | |
57a02c39 | 777 | static void __init ip4_frags_ctl_register(void) |
7d291ebb | 778 | { |
43444757 | 779 | register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table); |
7d291ebb | 780 | } |
8d8354d2 | 781 | #else |
aa1f731e | 782 | static int ip4_frags_ns_ctl_register(struct net *net) |
8d8354d2 PE |
783 | { |
784 | return 0; | |
785 | } | |
e4a2d5c2 | 786 | |
aa1f731e | 787 | static void ip4_frags_ns_ctl_unregister(struct net *net) |
e4a2d5c2 PE |
788 | { |
789 | } | |
7d291ebb | 790 | |
aa1f731e | 791 | static void __init ip4_frags_ctl_register(void) |
7d291ebb PE |
792 | { |
793 | } | |
8d8354d2 PE |
794 | #endif |
795 | ||
2c8c1e72 | 796 | static int __net_init ipv4_frags_init_net(struct net *net) |
8d8354d2 | 797 | { |
787bea77 ED |
798 | int res; |
799 | ||
c2a93660 JDB |
800 | /* Fragment cache limits. |
801 | * | |
802 | * The fragment memory accounting code, (tries to) account for | |
803 | * the real memory usage, by measuring both the size of frag | |
804 | * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) | |
805 | * and the SKB's truesize. | |
806 | * | |
807 | * A 64K fragment consumes 129736 bytes (44*2944)+200 | |
808 | * (1500 truesize == 2944, sizeof(struct ipq) == 200) | |
809 | * | |
810 | * We will commit 4MB at one time. Should we cross that limit | |
811 | * we will prune down to 3MB, making room for approx 8 big 64K | |
812 | * fragments 8x128k. | |
e31e0bdc | 813 | */ |
c2a93660 JDB |
814 | net->ipv4.frags.high_thresh = 4 * 1024 * 1024; |
815 | net->ipv4.frags.low_thresh = 3 * 1024 * 1024; | |
b2fd5321 PE |
816 | /* |
817 | * Important NOTE! Fragment queue must be destroyed before MSL expires. | |
818 | * RFC791 is wrong proposing to prolongate timer each fragment arrival | |
819 | * by TTL. | |
820 | */ | |
821 | net->ipv4.frags.timeout = IP_FRAG_TIME; | |
822 | ||
0fbf4cb2 | 823 | net->ipv4.frags.max_dist = 64; |
093ba729 | 824 | net->ipv4.frags.f = &ip4_frags; |
0fbf4cb2 | 825 | |
787bea77 ED |
826 | res = inet_frags_init_net(&net->ipv4.frags); |
827 | if (res < 0) | |
828 | return res; | |
829 | res = ip4_frags_ns_ctl_register(net); | |
830 | if (res < 0) | |
093ba729 | 831 | inet_frags_exit_net(&net->ipv4.frags); |
787bea77 | 832 | return res; |
8d8354d2 PE |
833 | } |
834 | ||
2c8c1e72 | 835 | static void __net_exit ipv4_frags_exit_net(struct net *net) |
81566e83 | 836 | { |
0a64b4b8 | 837 | ip4_frags_ns_ctl_unregister(net); |
093ba729 | 838 | inet_frags_exit_net(&net->ipv4.frags); |
81566e83 PE |
839 | } |
840 | ||
841 | static struct pernet_operations ip4_frags_ops = { | |
842 | .init = ipv4_frags_init_net, | |
843 | .exit = ipv4_frags_exit_net, | |
844 | }; | |
845 | ||
648700f7 ED |
846 | |
847 | static u32 ip4_key_hashfn(const void *data, u32 len, u32 seed) | |
848 | { | |
849 | return jhash2(data, | |
850 | sizeof(struct frag_v4_compare_key) / sizeof(u32), seed); | |
851 | } | |
852 | ||
853 | static u32 ip4_obj_hashfn(const void *data, u32 len, u32 seed) | |
854 | { | |
855 | const struct inet_frag_queue *fq = data; | |
856 | ||
857 | return jhash2((const u32 *)&fq->key.v4, | |
858 | sizeof(struct frag_v4_compare_key) / sizeof(u32), seed); | |
859 | } | |
860 | ||
861 | static int ip4_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr) | |
862 | { | |
863 | const struct frag_v4_compare_key *key = arg->key; | |
864 | const struct inet_frag_queue *fq = ptr; | |
865 | ||
866 | return !!memcmp(&fq->key, key, sizeof(*key)); | |
867 | } | |
868 | ||
869 | static const struct rhashtable_params ip4_rhash_params = { | |
870 | .head_offset = offsetof(struct inet_frag_queue, node), | |
871 | .key_offset = offsetof(struct inet_frag_queue, key), | |
872 | .key_len = sizeof(struct frag_v4_compare_key), | |
873 | .hashfn = ip4_key_hashfn, | |
874 | .obj_hashfn = ip4_obj_hashfn, | |
875 | .obj_cmpfn = ip4_obj_cmpfn, | |
876 | .automatic_shrinking = true, | |
877 | }; | |
878 | ||
b7aa0bf7 | 879 | void __init ipfrag_init(void) |
1da177e4 | 880 | { |
c6fda282 | 881 | ip4_frags.constructor = ip4_frag_init; |
1e4b8287 | 882 | ip4_frags.destructor = ip4_frag_free; |
1e4b8287 | 883 | ip4_frags.qsize = sizeof(struct ipq); |
e521db9d | 884 | ip4_frags.frag_expire = ip_expire; |
d4ad4d22 | 885 | ip4_frags.frags_cache_name = ip_frag_cache_name; |
648700f7 | 886 | ip4_frags.rhash_params = ip4_rhash_params; |
d4ad4d22 NA |
887 | if (inet_frags_init(&ip4_frags)) |
888 | panic("IP: failed to allocate ip4_frags cache\n"); | |
483a6e4f ED |
889 | ip4_frags_ctl_register(); |
890 | register_pernet_subsys(&ip4_frags_ops); | |
1da177e4 | 891 | } |