| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* | 
|  | 2 | *	IPv6 fragment reassembly | 
|  | 3 | *	Linux INET6 implementation | 
|  | 4 | * | 
|  | 5 | *	Authors: | 
|  | 6 | *	Pedro Roque		<roque@di.fc.ul.pt> | 
|  | 7 | * | 
|  | 8 | *	$Id: reassembly.c,v 1.26 2001/03/07 22:00:57 davem Exp $ | 
|  | 9 | * | 
|  | 10 | *	Based on: net/ipv4/ip_fragment.c | 
|  | 11 | * | 
|  | 12 | *	This program is free software; you can redistribute it and/or | 
|  | 13 | *      modify it under the terms of the GNU General Public License | 
|  | 14 | *      as published by the Free Software Foundation; either version | 
|  | 15 | *      2 of the License, or (at your option) any later version. | 
|  | 16 | */ | 
|  | 17 |  | 
|  | 18 | /* | 
|  | 19 | *	Fixes: | 
|  | 20 | *	Andi Kleen	Make it work with multiple hosts. | 
|  | 21 | *			More RFC compliance. | 
|  | 22 | * | 
|  | 23 | *      Horst von Brand Add missing #include <linux/string.h> | 
|  | 24 | *	Alexey Kuznetsov	SMP races, threading, cleanup. | 
|  | 25 | *	Patrick McHardy		LRU queue of frag heads for evictor. | 
|  | 26 | *	Mitsuru KANDA @USAGI	Register inet6_protocol{}. | 
|  | 27 | *	David Stevens and | 
|  | 28 | *	YOSHIFUJI,H. @USAGI	Always remove fragment header to | 
|  | 29 | *				calculate ICV correctly. | 
|  | 30 | */ | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <linux/errno.h> | 
|  | 32 | #include <linux/types.h> | 
|  | 33 | #include <linux/string.h> | 
|  | 34 | #include <linux/socket.h> | 
|  | 35 | #include <linux/sockios.h> | 
|  | 36 | #include <linux/jiffies.h> | 
|  | 37 | #include <linux/net.h> | 
|  | 38 | #include <linux/list.h> | 
|  | 39 | #include <linux/netdevice.h> | 
|  | 40 | #include <linux/in6.h> | 
|  | 41 | #include <linux/ipv6.h> | 
|  | 42 | #include <linux/icmpv6.h> | 
|  | 43 | #include <linux/random.h> | 
|  | 44 | #include <linux/jhash.h> | 
|  | 45 |  | 
|  | 46 | #include <net/sock.h> | 
|  | 47 | #include <net/snmp.h> | 
|  | 48 |  | 
|  | 49 | #include <net/ipv6.h> | 
|  | 50 | #include <net/protocol.h> | 
|  | 51 | #include <net/transp_v6.h> | 
|  | 52 | #include <net/rawv6.h> | 
|  | 53 | #include <net/ndisc.h> | 
|  | 54 | #include <net/addrconf.h> | 
|  | 55 |  | 
|  | 56 | int sysctl_ip6frag_high_thresh = 256*1024; | 
|  | 57 | int sysctl_ip6frag_low_thresh = 192*1024; | 
|  | 58 |  | 
|  | 59 | int sysctl_ip6frag_time = IPV6_FRAG_TIMEOUT; | 
|  | 60 |  | 
|  | 61 | struct ip6frag_skb_cb | 
|  | 62 | { | 
|  | 63 | struct inet6_skb_parm	h; | 
|  | 64 | int			offset; | 
|  | 65 | }; | 
|  | 66 |  | 
|  | 67 | #define FRAG6_CB(skb)	((struct ip6frag_skb_cb*)((skb)->cb)) | 
|  | 68 |  | 
|  | 69 |  | 
|  | 70 | /* | 
|  | 71 | *	Equivalent of ipv4 struct ipq | 
|  | 72 | */ | 
|  | 73 |  | 
|  | 74 | struct frag_queue | 
|  | 75 | { | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 76 | struct hlist_node	list; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | struct list_head lru_list;		/* lru list member	*/ | 
|  | 78 |  | 
|  | 79 | __u32			id;		/* fragment id		*/ | 
|  | 80 | struct in6_addr		saddr; | 
|  | 81 | struct in6_addr		daddr; | 
|  | 82 |  | 
|  | 83 | spinlock_t		lock; | 
|  | 84 | atomic_t		refcnt; | 
|  | 85 | struct timer_list	timer;		/* expire timer		*/ | 
|  | 86 | struct sk_buff		*fragments; | 
|  | 87 | int			len; | 
|  | 88 | int			meat; | 
|  | 89 | int			iif; | 
|  | 90 | struct timeval		stamp; | 
|  | 91 | unsigned int		csum; | 
|  | 92 | __u8			last_in;	/* has first/last segment arrived? */ | 
|  | 93 | #define COMPLETE		4 | 
|  | 94 | #define FIRST_IN		2 | 
|  | 95 | #define LAST_IN			1 | 
|  | 96 | __u16			nhoffset; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | }; | 
|  | 98 |  | 
|  | 99 | /* Hash table. */ | 
|  | 100 |  | 
|  | 101 | #define IP6Q_HASHSZ	64 | 
|  | 102 |  | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 103 | static struct hlist_head ip6_frag_hash[IP6Q_HASHSZ]; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | static DEFINE_RWLOCK(ip6_frag_lock); | 
|  | 105 | static u32 ip6_frag_hash_rnd; | 
|  | 106 | static LIST_HEAD(ip6_frag_lru_list); | 
|  | 107 | int ip6_frag_nqueues = 0; | 
|  | 108 |  | 
|  | 109 | static __inline__ void __fq_unlink(struct frag_queue *fq) | 
|  | 110 | { | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 111 | hlist_del(&fq->list); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | list_del(&fq->lru_list); | 
|  | 113 | ip6_frag_nqueues--; | 
|  | 114 | } | 
|  | 115 |  | 
|  | 116 | static __inline__ void fq_unlink(struct frag_queue *fq) | 
|  | 117 | { | 
|  | 118 | write_lock(&ip6_frag_lock); | 
|  | 119 | __fq_unlink(fq); | 
|  | 120 | write_unlock(&ip6_frag_lock); | 
|  | 121 | } | 
|  | 122 |  | 
| Zach Brown | f6596f9 | 2006-04-10 16:05:34 -0700 | [diff] [blame] | 123 | /* | 
|  | 124 | * callers should be careful not to use the hash value outside the ipfrag_lock | 
|  | 125 | * as doing so could race with ipfrag_hash_rnd being recalculated. | 
|  | 126 | */ | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | static unsigned int ip6qhashfn(u32 id, struct in6_addr *saddr, | 
|  | 128 | struct in6_addr *daddr) | 
|  | 129 | { | 
|  | 130 | u32 a, b, c; | 
|  | 131 |  | 
|  | 132 | a = saddr->s6_addr32[0]; | 
|  | 133 | b = saddr->s6_addr32[1]; | 
|  | 134 | c = saddr->s6_addr32[2]; | 
|  | 135 |  | 
|  | 136 | a += JHASH_GOLDEN_RATIO; | 
|  | 137 | b += JHASH_GOLDEN_RATIO; | 
|  | 138 | c += ip6_frag_hash_rnd; | 
|  | 139 | __jhash_mix(a, b, c); | 
|  | 140 |  | 
|  | 141 | a += saddr->s6_addr32[3]; | 
|  | 142 | b += daddr->s6_addr32[0]; | 
|  | 143 | c += daddr->s6_addr32[1]; | 
|  | 144 | __jhash_mix(a, b, c); | 
|  | 145 |  | 
|  | 146 | a += daddr->s6_addr32[2]; | 
|  | 147 | b += daddr->s6_addr32[3]; | 
|  | 148 | c += id; | 
|  | 149 | __jhash_mix(a, b, c); | 
|  | 150 |  | 
|  | 151 | return c & (IP6Q_HASHSZ - 1); | 
|  | 152 | } | 
|  | 153 |  | 
|  | 154 | static struct timer_list ip6_frag_secret_timer; | 
|  | 155 | int sysctl_ip6frag_secret_interval = 10 * 60 * HZ; | 
|  | 156 |  | 
|  | 157 | static void ip6_frag_secret_rebuild(unsigned long dummy) | 
|  | 158 | { | 
|  | 159 | unsigned long now = jiffies; | 
|  | 160 | int i; | 
|  | 161 |  | 
|  | 162 | write_lock(&ip6_frag_lock); | 
|  | 163 | get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32)); | 
|  | 164 | for (i = 0; i < IP6Q_HASHSZ; i++) { | 
|  | 165 | struct frag_queue *q; | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 166 | struct hlist_node *p, *n; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 |  | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 168 | hlist_for_each_entry_safe(q, p, n, &ip6_frag_hash[i], list) { | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | unsigned int hval = ip6qhashfn(q->id, | 
|  | 170 | &q->saddr, | 
|  | 171 | &q->daddr); | 
|  | 172 |  | 
|  | 173 | if (hval != i) { | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 174 | hlist_del(&q->list); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 |  | 
|  | 176 | /* Relink to new hash chain. */ | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 177 | hlist_add_head(&q->list, | 
|  | 178 | &ip6_frag_hash[hval]); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 |  | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 180 | } | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | } | 
|  | 182 | } | 
|  | 183 | write_unlock(&ip6_frag_lock); | 
|  | 184 |  | 
|  | 185 | mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval); | 
|  | 186 | } | 
|  | 187 |  | 
|  | 188 | atomic_t ip6_frag_mem = ATOMIC_INIT(0); | 
|  | 189 |  | 
|  | 190 | /* Memory Tracking Functions. */ | 
|  | 191 | static inline void frag_kfree_skb(struct sk_buff *skb, int *work) | 
|  | 192 | { | 
|  | 193 | if (work) | 
|  | 194 | *work -= skb->truesize; | 
|  | 195 | atomic_sub(skb->truesize, &ip6_frag_mem); | 
|  | 196 | kfree_skb(skb); | 
|  | 197 | } | 
|  | 198 |  | 
|  | 199 | static inline void frag_free_queue(struct frag_queue *fq, int *work) | 
|  | 200 | { | 
|  | 201 | if (work) | 
|  | 202 | *work -= sizeof(struct frag_queue); | 
|  | 203 | atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem); | 
|  | 204 | kfree(fq); | 
|  | 205 | } | 
|  | 206 |  | 
|  | 207 | static inline struct frag_queue *frag_alloc_queue(void) | 
|  | 208 | { | 
| Ingo Oeser | 78c784c | 2006-03-20 23:01:17 -0800 | [diff] [blame] | 209 | struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 |  | 
|  | 211 | if(!fq) | 
|  | 212 | return NULL; | 
|  | 213 | atomic_add(sizeof(struct frag_queue), &ip6_frag_mem); | 
|  | 214 | return fq; | 
|  | 215 | } | 
|  | 216 |  | 
|  | 217 | /* Destruction primitives. */ | 
|  | 218 |  | 
|  | 219 | /* Complete destruction of fq. */ | 
|  | 220 | static void ip6_frag_destroy(struct frag_queue *fq, int *work) | 
|  | 221 | { | 
|  | 222 | struct sk_buff *fp; | 
|  | 223 |  | 
|  | 224 | BUG_TRAP(fq->last_in&COMPLETE); | 
|  | 225 | BUG_TRAP(del_timer(&fq->timer) == 0); | 
|  | 226 |  | 
|  | 227 | /* Release all fragment data. */ | 
|  | 228 | fp = fq->fragments; | 
|  | 229 | while (fp) { | 
|  | 230 | struct sk_buff *xp = fp->next; | 
|  | 231 |  | 
|  | 232 | frag_kfree_skb(fp, work); | 
|  | 233 | fp = xp; | 
|  | 234 | } | 
|  | 235 |  | 
|  | 236 | frag_free_queue(fq, work); | 
|  | 237 | } | 
|  | 238 |  | 
|  | 239 | static __inline__ void fq_put(struct frag_queue *fq, int *work) | 
|  | 240 | { | 
|  | 241 | if (atomic_dec_and_test(&fq->refcnt)) | 
|  | 242 | ip6_frag_destroy(fq, work); | 
|  | 243 | } | 
|  | 244 |  | 
|  | 245 | /* Kill fq entry. It is not destroyed immediately, | 
|  | 246 | * because caller (and someone more) holds reference count. | 
|  | 247 | */ | 
|  | 248 | static __inline__ void fq_kill(struct frag_queue *fq) | 
|  | 249 | { | 
|  | 250 | if (del_timer(&fq->timer)) | 
|  | 251 | atomic_dec(&fq->refcnt); | 
|  | 252 |  | 
|  | 253 | if (!(fq->last_in & COMPLETE)) { | 
|  | 254 | fq_unlink(fq); | 
|  | 255 | atomic_dec(&fq->refcnt); | 
|  | 256 | fq->last_in |= COMPLETE; | 
|  | 257 | } | 
|  | 258 | } | 
|  | 259 |  | 
|  | 260 | static void ip6_evictor(void) | 
|  | 261 | { | 
|  | 262 | struct frag_queue *fq; | 
|  | 263 | struct list_head *tmp; | 
|  | 264 | int work; | 
|  | 265 |  | 
|  | 266 | work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh; | 
|  | 267 | if (work <= 0) | 
|  | 268 | return; | 
|  | 269 |  | 
|  | 270 | while(work > 0) { | 
|  | 271 | read_lock(&ip6_frag_lock); | 
|  | 272 | if (list_empty(&ip6_frag_lru_list)) { | 
|  | 273 | read_unlock(&ip6_frag_lock); | 
|  | 274 | return; | 
|  | 275 | } | 
|  | 276 | tmp = ip6_frag_lru_list.next; | 
|  | 277 | fq = list_entry(tmp, struct frag_queue, lru_list); | 
|  | 278 | atomic_inc(&fq->refcnt); | 
|  | 279 | read_unlock(&ip6_frag_lock); | 
|  | 280 |  | 
|  | 281 | spin_lock(&fq->lock); | 
|  | 282 | if (!(fq->last_in&COMPLETE)) | 
|  | 283 | fq_kill(fq); | 
|  | 284 | spin_unlock(&fq->lock); | 
|  | 285 |  | 
|  | 286 | fq_put(fq, &work); | 
|  | 287 | IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); | 
|  | 288 | } | 
|  | 289 | } | 
|  | 290 |  | 
|  | 291 | static void ip6_frag_expire(unsigned long data) | 
|  | 292 | { | 
|  | 293 | struct frag_queue *fq = (struct frag_queue *) data; | 
| Ingo Oeser | 78c784c | 2006-03-20 23:01:17 -0800 | [diff] [blame] | 294 | struct net_device *dev; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 |  | 
|  | 296 | spin_lock(&fq->lock); | 
|  | 297 |  | 
|  | 298 | if (fq->last_in & COMPLETE) | 
|  | 299 | goto out; | 
|  | 300 |  | 
|  | 301 | fq_kill(fq); | 
|  | 302 |  | 
|  | 303 | IP6_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT); | 
|  | 304 | IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); | 
|  | 305 |  | 
| Ingo Oeser | 78c784c | 2006-03-20 23:01:17 -0800 | [diff] [blame] | 306 | /* Don't send error if the first segment did not arrive. */ | 
|  | 307 | if (!(fq->last_in&FIRST_IN) || !fq->fragments) | 
|  | 308 | goto out; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 |  | 
| Ingo Oeser | 78c784c | 2006-03-20 23:01:17 -0800 | [diff] [blame] | 310 | dev = dev_get_by_index(fq->iif); | 
|  | 311 | if (!dev) | 
|  | 312 | goto out; | 
|  | 313 |  | 
|  | 314 | /* | 
|  | 315 | But use as source device on which LAST ARRIVED | 
|  | 316 | segment was received. And do not use fq->dev | 
|  | 317 | pointer directly, device might already disappeared. | 
|  | 318 | */ | 
|  | 319 | fq->fragments->dev = dev; | 
|  | 320 | icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev); | 
|  | 321 | dev_put(dev); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | out: | 
|  | 323 | spin_unlock(&fq->lock); | 
|  | 324 | fq_put(fq, NULL); | 
|  | 325 | } | 
|  | 326 |  | 
|  | 327 | /* Creation primitives. */ | 
|  | 328 |  | 
|  | 329 |  | 
| Zach Brown | f6596f9 | 2006-04-10 16:05:34 -0700 | [diff] [blame] | 330 | static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in) | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | { | 
|  | 332 | struct frag_queue *fq; | 
| Zach Brown | f6596f9 | 2006-04-10 16:05:34 -0700 | [diff] [blame] | 333 | unsigned int hash; | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 334 | #ifdef CONFIG_SMP | 
|  | 335 | struct hlist_node *n; | 
|  | 336 | #endif | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 |  | 
|  | 338 | write_lock(&ip6_frag_lock); | 
| Zach Brown | f6596f9 | 2006-04-10 16:05:34 -0700 | [diff] [blame] | 339 | hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | #ifdef CONFIG_SMP | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 341 | hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) { | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | if (fq->id == fq_in->id && | 
|  | 343 | ipv6_addr_equal(&fq_in->saddr, &fq->saddr) && | 
|  | 344 | ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) { | 
|  | 345 | atomic_inc(&fq->refcnt); | 
|  | 346 | write_unlock(&ip6_frag_lock); | 
|  | 347 | fq_in->last_in |= COMPLETE; | 
|  | 348 | fq_put(fq_in, NULL); | 
|  | 349 | return fq; | 
|  | 350 | } | 
|  | 351 | } | 
|  | 352 | #endif | 
|  | 353 | fq = fq_in; | 
|  | 354 |  | 
|  | 355 | if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time)) | 
|  | 356 | atomic_inc(&fq->refcnt); | 
|  | 357 |  | 
|  | 358 | atomic_inc(&fq->refcnt); | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 359 | hlist_add_head(&fq->list, &ip6_frag_hash[hash]); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | INIT_LIST_HEAD(&fq->lru_list); | 
|  | 361 | list_add_tail(&fq->lru_list, &ip6_frag_lru_list); | 
|  | 362 | ip6_frag_nqueues++; | 
|  | 363 | write_unlock(&ip6_frag_lock); | 
|  | 364 | return fq; | 
|  | 365 | } | 
|  | 366 |  | 
|  | 367 |  | 
|  | 368 | static struct frag_queue * | 
| Zach Brown | f6596f9 | 2006-04-10 16:05:34 -0700 | [diff] [blame] | 369 | ip6_frag_create(u32 id, struct in6_addr *src, struct in6_addr *dst) | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | { | 
|  | 371 | struct frag_queue *fq; | 
|  | 372 |  | 
|  | 373 | if ((fq = frag_alloc_queue()) == NULL) | 
|  | 374 | goto oom; | 
|  | 375 |  | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 376 | fq->id = id; | 
|  | 377 | ipv6_addr_copy(&fq->saddr, src); | 
|  | 378 | ipv6_addr_copy(&fq->daddr, dst); | 
|  | 379 |  | 
|  | 380 | init_timer(&fq->timer); | 
|  | 381 | fq->timer.function = ip6_frag_expire; | 
|  | 382 | fq->timer.data = (long) fq; | 
|  | 383 | spin_lock_init(&fq->lock); | 
|  | 384 | atomic_set(&fq->refcnt, 1); | 
|  | 385 |  | 
| Zach Brown | f6596f9 | 2006-04-10 16:05:34 -0700 | [diff] [blame] | 386 | return ip6_frag_intern(fq); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 387 |  | 
|  | 388 | oom: | 
|  | 389 | IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); | 
|  | 390 | return NULL; | 
|  | 391 | } | 
|  | 392 |  | 
|  | 393 | static __inline__ struct frag_queue * | 
|  | 394 | fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst) | 
|  | 395 | { | 
|  | 396 | struct frag_queue *fq; | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 397 | struct hlist_node *n; | 
| Zach Brown | f6596f9 | 2006-04-10 16:05:34 -0700 | [diff] [blame] | 398 | unsigned int hash; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 |  | 
|  | 400 | read_lock(&ip6_frag_lock); | 
| Zach Brown | f6596f9 | 2006-04-10 16:05:34 -0700 | [diff] [blame] | 401 | hash = ip6qhashfn(id, src, dst); | 
| Yasuyuki Kozakai | e7c8a41 | 2005-11-16 12:55:37 -0800 | [diff] [blame] | 402 | hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) { | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 403 | if (fq->id == id && | 
|  | 404 | ipv6_addr_equal(src, &fq->saddr) && | 
|  | 405 | ipv6_addr_equal(dst, &fq->daddr)) { | 
|  | 406 | atomic_inc(&fq->refcnt); | 
|  | 407 | read_unlock(&ip6_frag_lock); | 
|  | 408 | return fq; | 
|  | 409 | } | 
|  | 410 | } | 
|  | 411 | read_unlock(&ip6_frag_lock); | 
|  | 412 |  | 
| Zach Brown | f6596f9 | 2006-04-10 16:05:34 -0700 | [diff] [blame] | 413 | return ip6_frag_create(id, src, dst); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | } | 
|  | 415 |  | 
|  | 416 |  | 
|  | 417 | static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, | 
|  | 418 | struct frag_hdr *fhdr, int nhoff) | 
|  | 419 | { | 
|  | 420 | struct sk_buff *prev, *next; | 
|  | 421 | int offset, end; | 
|  | 422 |  | 
|  | 423 | if (fq->last_in & COMPLETE) | 
|  | 424 | goto err; | 
|  | 425 |  | 
|  | 426 | offset = ntohs(fhdr->frag_off) & ~0x7; | 
|  | 427 | end = offset + (ntohs(skb->nh.ipv6h->payload_len) - | 
|  | 428 | ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1))); | 
|  | 429 |  | 
|  | 430 | if ((unsigned int)end > IPV6_MAXPLEN) { | 
|  | 431 | IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); | 
|  | 432 | icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw); | 
|  | 433 | return; | 
|  | 434 | } | 
|  | 435 |  | 
|  | 436 | if (skb->ip_summed == CHECKSUM_HW) | 
|  | 437 | skb->csum = csum_sub(skb->csum, | 
|  | 438 | csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 0)); | 
|  | 439 |  | 
|  | 440 | /* Is this the final fragment? */ | 
|  | 441 | if (!(fhdr->frag_off & htons(IP6_MF))) { | 
|  | 442 | /* If we already have some bits beyond end | 
|  | 443 | * or have different end, the segment is corrupted. | 
|  | 444 | */ | 
|  | 445 | if (end < fq->len || | 
|  | 446 | ((fq->last_in & LAST_IN) && end != fq->len)) | 
|  | 447 | goto err; | 
|  | 448 | fq->last_in |= LAST_IN; | 
|  | 449 | fq->len = end; | 
|  | 450 | } else { | 
|  | 451 | /* Check if the fragment is rounded to 8 bytes. | 
|  | 452 | * Required by the RFC. | 
|  | 453 | */ | 
|  | 454 | if (end & 0x7) { | 
|  | 455 | /* RFC2460 says always send parameter problem in | 
|  | 456 | * this case. -DaveM | 
|  | 457 | */ | 
|  | 458 | IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); | 
|  | 459 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, | 
|  | 460 | offsetof(struct ipv6hdr, payload_len)); | 
|  | 461 | return; | 
|  | 462 | } | 
|  | 463 | if (end > fq->len) { | 
|  | 464 | /* Some bits beyond end -> corruption. */ | 
|  | 465 | if (fq->last_in & LAST_IN) | 
|  | 466 | goto err; | 
|  | 467 | fq->len = end; | 
|  | 468 | } | 
|  | 469 | } | 
|  | 470 |  | 
|  | 471 | if (end == offset) | 
|  | 472 | goto err; | 
|  | 473 |  | 
|  | 474 | /* Point into the IP datagram 'data' part. */ | 
|  | 475 | if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) | 
|  | 476 | goto err; | 
| Stephen Hemminger | 42ca89c | 2005-09-08 12:57:43 -0700 | [diff] [blame] | 477 |  | 
|  | 478 | if (pskb_trim_rcsum(skb, end - offset)) | 
|  | 479 | goto err; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 |  | 
|  | 481 | /* Find out which fragments are in front and at the back of us | 
|  | 482 | * in the chain of fragments so far.  We must know where to put | 
|  | 483 | * this fragment, right? | 
|  | 484 | */ | 
|  | 485 | prev = NULL; | 
|  | 486 | for(next = fq->fragments; next != NULL; next = next->next) { | 
|  | 487 | if (FRAG6_CB(next)->offset >= offset) | 
|  | 488 | break;	/* bingo! */ | 
|  | 489 | prev = next; | 
|  | 490 | } | 
|  | 491 |  | 
|  | 492 | /* We found where to put this one.  Check for overlap with | 
|  | 493 | * preceding fragment, and, if needed, align things so that | 
|  | 494 | * any overlaps are eliminated. | 
|  | 495 | */ | 
|  | 496 | if (prev) { | 
|  | 497 | int i = (FRAG6_CB(prev)->offset + prev->len) - offset; | 
|  | 498 |  | 
|  | 499 | if (i > 0) { | 
|  | 500 | offset += i; | 
|  | 501 | if (end <= offset) | 
|  | 502 | goto err; | 
|  | 503 | if (!pskb_pull(skb, i)) | 
|  | 504 | goto err; | 
|  | 505 | if (skb->ip_summed != CHECKSUM_UNNECESSARY) | 
|  | 506 | skb->ip_summed = CHECKSUM_NONE; | 
|  | 507 | } | 
|  | 508 | } | 
|  | 509 |  | 
|  | 510 | /* Look for overlap with succeeding segments. | 
|  | 511 | * If we can merge fragments, do it. | 
|  | 512 | */ | 
|  | 513 | while (next && FRAG6_CB(next)->offset < end) { | 
|  | 514 | int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */ | 
|  | 515 |  | 
|  | 516 | if (i < next->len) { | 
|  | 517 | /* Eat head of the next overlapped fragment | 
|  | 518 | * and leave the loop. The next ones cannot overlap. | 
|  | 519 | */ | 
|  | 520 | if (!pskb_pull(next, i)) | 
|  | 521 | goto err; | 
|  | 522 | FRAG6_CB(next)->offset += i;	/* next fragment */ | 
|  | 523 | fq->meat -= i; | 
|  | 524 | if (next->ip_summed != CHECKSUM_UNNECESSARY) | 
|  | 525 | next->ip_summed = CHECKSUM_NONE; | 
|  | 526 | break; | 
|  | 527 | } else { | 
|  | 528 | struct sk_buff *free_it = next; | 
|  | 529 |  | 
|  | 530 | /* Old fragment is completely overridden with | 
|  | 531 | * new one drop it. | 
|  | 532 | */ | 
|  | 533 | next = next->next; | 
|  | 534 |  | 
|  | 535 | if (prev) | 
|  | 536 | prev->next = next; | 
|  | 537 | else | 
|  | 538 | fq->fragments = next; | 
|  | 539 |  | 
|  | 540 | fq->meat -= free_it->len; | 
|  | 541 | frag_kfree_skb(free_it, NULL); | 
|  | 542 | } | 
|  | 543 | } | 
|  | 544 |  | 
|  | 545 | FRAG6_CB(skb)->offset = offset; | 
|  | 546 |  | 
|  | 547 | /* Insert this fragment in the chain of fragments. */ | 
|  | 548 | skb->next = next; | 
|  | 549 | if (prev) | 
|  | 550 | prev->next = skb; | 
|  | 551 | else | 
|  | 552 | fq->fragments = skb; | 
|  | 553 |  | 
|  | 554 | if (skb->dev) | 
|  | 555 | fq->iif = skb->dev->ifindex; | 
|  | 556 | skb->dev = NULL; | 
| Patrick McHardy | a61bbcf | 2005-08-14 17:24:31 -0700 | [diff] [blame] | 557 | skb_get_timestamp(skb, &fq->stamp); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | fq->meat += skb->len; | 
|  | 559 | atomic_add(skb->truesize, &ip6_frag_mem); | 
|  | 560 |  | 
|  | 561 | /* The first fragment. | 
|  | 562 | * nhoffset is obtained from the first fragment, of course. | 
|  | 563 | */ | 
|  | 564 | if (offset == 0) { | 
|  | 565 | fq->nhoffset = nhoff; | 
|  | 566 | fq->last_in |= FIRST_IN; | 
|  | 567 | } | 
|  | 568 | write_lock(&ip6_frag_lock); | 
|  | 569 | list_move_tail(&fq->lru_list, &ip6_frag_lru_list); | 
|  | 570 | write_unlock(&ip6_frag_lock); | 
|  | 571 | return; | 
|  | 572 |  | 
|  | 573 | err: | 
|  | 574 | IP6_INC_STATS(IPSTATS_MIB_REASMFAILS); | 
|  | 575 | kfree_skb(skb); | 
|  | 576 | } | 
|  | 577 |  | 
|  | 578 | /* | 
|  | 579 | *	Check if this packet is complete. | 
|  | 580 | *	Returns NULL on failure by any reason, and pointer | 
|  | 581 | *	to current nexthdr field in reassembled frame. | 
|  | 582 | * | 
|  | 583 | *	It is called with locked fq, and caller must check that | 
|  | 584 | *	queue is eligible for reassembly i.e. it is not COMPLETE, | 
|  | 585 | *	the last and the first frames arrived and all the bits are here. | 
|  | 586 | */ | 
|  | 587 | static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in, | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 588 | struct net_device *dev) | 
|  | 589 | { | 
|  | 590 | struct sk_buff *fp, *head = fq->fragments; | 
|  | 591 | int    payload_len; | 
|  | 592 | unsigned int nhoff; | 
|  | 593 |  | 
|  | 594 | fq_kill(fq); | 
|  | 595 |  | 
|  | 596 | BUG_TRAP(head != NULL); | 
|  | 597 | BUG_TRAP(FRAG6_CB(head)->offset == 0); | 
|  | 598 |  | 
|  | 599 | /* Unfragmented part is taken from the first segment. */ | 
|  | 600 | payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len - sizeof(struct frag_hdr); | 
|  | 601 | if (payload_len > IPV6_MAXPLEN) | 
|  | 602 | goto out_oversize; | 
|  | 603 |  | 
|  | 604 | /* Head of list must not be cloned. */ | 
|  | 605 | if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) | 
|  | 606 | goto out_oom; | 
|  | 607 |  | 
|  | 608 | /* If the first fragment is fragmented itself, we split | 
|  | 609 | * it to two chunks: the first with data and paged part | 
|  | 610 | * and the second, holding only fragments. */ | 
|  | 611 | if (skb_shinfo(head)->frag_list) { | 
|  | 612 | struct sk_buff *clone; | 
|  | 613 | int i, plen = 0; | 
|  | 614 |  | 
|  | 615 | if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) | 
|  | 616 | goto out_oom; | 
|  | 617 | clone->next = head->next; | 
|  | 618 | head->next = clone; | 
|  | 619 | skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; | 
|  | 620 | skb_shinfo(head)->frag_list = NULL; | 
|  | 621 | for (i=0; i<skb_shinfo(head)->nr_frags; i++) | 
|  | 622 | plen += skb_shinfo(head)->frags[i].size; | 
|  | 623 | clone->len = clone->data_len = head->data_len - plen; | 
|  | 624 | head->data_len -= clone->len; | 
|  | 625 | head->len -= clone->len; | 
|  | 626 | clone->csum = 0; | 
|  | 627 | clone->ip_summed = head->ip_summed; | 
|  | 628 | atomic_add(clone->truesize, &ip6_frag_mem); | 
|  | 629 | } | 
|  | 630 |  | 
|  | 631 | /* We have to remove fragment header from datagram and to relocate | 
|  | 632 | * header in order to calculate ICV correctly. */ | 
|  | 633 | nhoff = fq->nhoffset; | 
|  | 634 | head->nh.raw[nhoff] = head->h.raw[0]; | 
|  | 635 | memmove(head->head + sizeof(struct frag_hdr), head->head, | 
|  | 636 | (head->data - head->head) - sizeof(struct frag_hdr)); | 
|  | 637 | head->mac.raw += sizeof(struct frag_hdr); | 
|  | 638 | head->nh.raw += sizeof(struct frag_hdr); | 
|  | 639 |  | 
|  | 640 | skb_shinfo(head)->frag_list = head->next; | 
|  | 641 | head->h.raw = head->data; | 
|  | 642 | skb_push(head, head->data - head->nh.raw); | 
|  | 643 | atomic_sub(head->truesize, &ip6_frag_mem); | 
|  | 644 |  | 
|  | 645 | for (fp=head->next; fp; fp = fp->next) { | 
|  | 646 | head->data_len += fp->len; | 
|  | 647 | head->len += fp->len; | 
|  | 648 | if (head->ip_summed != fp->ip_summed) | 
|  | 649 | head->ip_summed = CHECKSUM_NONE; | 
|  | 650 | else if (head->ip_summed == CHECKSUM_HW) | 
|  | 651 | head->csum = csum_add(head->csum, fp->csum); | 
|  | 652 | head->truesize += fp->truesize; | 
|  | 653 | atomic_sub(fp->truesize, &ip6_frag_mem); | 
|  | 654 | } | 
|  | 655 |  | 
|  | 656 | head->next = NULL; | 
|  | 657 | head->dev = dev; | 
| Patrick McHardy | a61bbcf | 2005-08-14 17:24:31 -0700 | [diff] [blame] | 658 | skb_set_timestamp(head, &fq->stamp); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | head->nh.ipv6h->payload_len = htons(payload_len); | 
| Patrick McHardy | 951dbc8 | 2006-01-06 23:02:34 -0800 | [diff] [blame] | 660 | IP6CB(head)->nhoff = nhoff; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 |  | 
|  | 662 | *skb_in = head; | 
|  | 663 |  | 
|  | 664 | /* Yes, and fold redundant checksum back. 8) */ | 
|  | 665 | if (head->ip_summed == CHECKSUM_HW) | 
|  | 666 | head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum); | 
|  | 667 |  | 
|  | 668 | IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS); | 
|  | 669 | fq->fragments = NULL; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 670 | return 1; | 
|  | 671 |  | 
|  | 672 | out_oversize: | 
|  | 673 | if (net_ratelimit()) | 
|  | 674 | printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len); | 
|  | 675 | goto out_fail; | 
|  | 676 | out_oom: | 
|  | 677 | if (net_ratelimit()) | 
|  | 678 | printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n"); | 
|  | 679 | out_fail: | 
|  | 680 | IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); | 
|  | 681 | return -1; | 
|  | 682 | } | 
|  | 683 |  | 
| Patrick McHardy | 951dbc8 | 2006-01-06 23:02:34 -0800 | [diff] [blame] | 684 | static int ipv6_frag_rcv(struct sk_buff **skbp) | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 685 | { | 
|  | 686 | struct sk_buff *skb = *skbp; | 
|  | 687 | struct net_device *dev = skb->dev; | 
|  | 688 | struct frag_hdr *fhdr; | 
|  | 689 | struct frag_queue *fq; | 
|  | 690 | struct ipv6hdr *hdr; | 
|  | 691 |  | 
|  | 692 | hdr = skb->nh.ipv6h; | 
|  | 693 |  | 
|  | 694 | IP6_INC_STATS_BH(IPSTATS_MIB_REASMREQDS); | 
|  | 695 |  | 
|  | 696 | /* Jumbo payload inhibits frag. header */ | 
|  | 697 | if (hdr->payload_len==0) { | 
|  | 698 | IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS); | 
|  | 699 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw); | 
|  | 700 | return -1; | 
|  | 701 | } | 
|  | 702 | if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) { | 
|  | 703 | IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS); | 
|  | 704 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw); | 
|  | 705 | return -1; | 
|  | 706 | } | 
|  | 707 |  | 
|  | 708 | hdr = skb->nh.ipv6h; | 
|  | 709 | fhdr = (struct frag_hdr *)skb->h.raw; | 
|  | 710 |  | 
|  | 711 | if (!(fhdr->frag_off & htons(0xFFF9))) { | 
|  | 712 | /* It is not a fragmented frame */ | 
|  | 713 | skb->h.raw += sizeof(struct frag_hdr); | 
|  | 714 | IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS); | 
|  | 715 |  | 
| Patrick McHardy | 951dbc8 | 2006-01-06 23:02:34 -0800 | [diff] [blame] | 716 | IP6CB(skb)->nhoff = (u8*)fhdr - skb->nh.raw; | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 717 | return 1; | 
|  | 718 | } | 
|  | 719 |  | 
|  | 720 | if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh) | 
|  | 721 | ip6_evictor(); | 
|  | 722 |  | 
|  | 723 | if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) { | 
|  | 724 | int ret = -1; | 
|  | 725 |  | 
|  | 726 | spin_lock(&fq->lock); | 
|  | 727 |  | 
| Patrick McHardy | 951dbc8 | 2006-01-06 23:02:34 -0800 | [diff] [blame] | 728 | ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 |  | 
|  | 730 | if (fq->last_in == (FIRST_IN|LAST_IN) && | 
|  | 731 | fq->meat == fq->len) | 
| Patrick McHardy | 951dbc8 | 2006-01-06 23:02:34 -0800 | [diff] [blame] | 732 | ret = ip6_frag_reasm(fq, skbp, dev); | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 733 |  | 
|  | 734 | spin_unlock(&fq->lock); | 
|  | 735 | fq_put(fq, NULL); | 
|  | 736 | return ret; | 
|  | 737 | } | 
|  | 738 |  | 
|  | 739 | IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); | 
|  | 740 | kfree_skb(skb); | 
|  | 741 | return -1; | 
|  | 742 | } | 
|  | 743 |  | 
|  | 744 | static struct inet6_protocol frag_protocol = | 
|  | 745 | { | 
|  | 746 | .handler	=	ipv6_frag_rcv, | 
|  | 747 | .flags		=	INET6_PROTO_NOPOLICY, | 
|  | 748 | }; | 
|  | 749 |  | 
|  | 750 | void __init ipv6_frag_init(void) | 
|  | 751 | { | 
|  | 752 | if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0) | 
|  | 753 | printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n"); | 
|  | 754 |  | 
|  | 755 | ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^ | 
|  | 756 | (jiffies ^ (jiffies >> 6))); | 
|  | 757 |  | 
|  | 758 | init_timer(&ip6_frag_secret_timer); | 
|  | 759 | ip6_frag_secret_timer.function = ip6_frag_secret_rebuild; | 
|  | 760 | ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval; | 
|  | 761 | add_timer(&ip6_frag_secret_timer); | 
|  | 762 | } |