| 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 | } |