11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * INET An implementation of the TCP/IP protocol suite for the LINUX 31da177e4SLinus Torvalds * operating system. INET is implemented using the BSD Socket 41da177e4SLinus Torvalds * interface as the means of communication with the user level. 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * The IP fragmentation functionality. 71da177e4SLinus Torvalds * 81da177e4SLinus Torvalds * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG> 9113aa838SAlan Cox * Alan Cox <alan@lxorguk.ukuu.org.uk> 101da177e4SLinus Torvalds * 111da177e4SLinus Torvalds * Fixes: 121da177e4SLinus Torvalds * Alan Cox : Split from ip.c , see ip_input.c for history. 131da177e4SLinus Torvalds * David S. Miller : Begin massive cleanup... 141da177e4SLinus Torvalds * Andi Kleen : Add sysctls. 151da177e4SLinus Torvalds * xxxx : Overlapfrag bug. 161da177e4SLinus Torvalds * Ultima : ip_expire() kernel panic. 171da177e4SLinus Torvalds * Bill Hawes : Frag accounting and evictor fixes. 181da177e4SLinus Torvalds * John McDonald : 0 length frag bug. 191da177e4SLinus Torvalds * Alexey Kuznetsov: SMP races, threading, cleanup. 201da177e4SLinus Torvalds * Patrick McHardy : LRU queue of frag heads for evictor. 211da177e4SLinus Torvalds */ 221da177e4SLinus Torvalds 2389cee8b1SHerbert Xu #include <linux/compiler.h> 241da177e4SLinus Torvalds #include <linux/module.h> 251da177e4SLinus Torvalds #include <linux/types.h> 261da177e4SLinus Torvalds #include <linux/mm.h> 271da177e4SLinus Torvalds #include <linux/jiffies.h> 281da177e4SLinus Torvalds #include <linux/skbuff.h> 291da177e4SLinus Torvalds #include <linux/list.h> 301da177e4SLinus Torvalds #include <linux/ip.h> 311da177e4SLinus Torvalds #include <linux/icmp.h> 321da177e4SLinus Torvalds #include <linux/netdevice.h> 331da177e4SLinus Torvalds #include <linux/jhash.h> 341da177e4SLinus Torvalds #include <linux/random.h> 355a0e3ad6STejun Heo #include <linux/slab.h> 36e9017b55SShan Wei #include <net/route.h> 37e9017b55SShan Wei #include <net/dst.h> 381da177e4SLinus Torvalds #include <net/sock.h> 391da177e4SLinus Torvalds #include <net/ip.h> 401da177e4SLinus Torvalds #include <net/icmp.h> 411da177e4SLinus Torvalds #include <net/checksum.h> 4289cee8b1SHerbert Xu #include <net/inetpeer.h> 435ab11c98SPavel Emelyanov #include <net/inet_frag.h> 441da177e4SLinus Torvalds #include <linux/tcp.h> 451da177e4SLinus Torvalds #include <linux/udp.h> 461da177e4SLinus Torvalds #include <linux/inet.h> 471da177e4SLinus Torvalds #include <linux/netfilter_ipv4.h> 486623e3b2SEric Dumazet #include <net/inet_ecn.h> 491da177e4SLinus Torvalds 501da177e4SLinus Torvalds /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6 511da177e4SLinus Torvalds * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c 521da177e4SLinus Torvalds * as well. Or notify me, at least. --ANK 531da177e4SLinus Torvalds */ 541da177e4SLinus Torvalds 558d8354d2SPavel Emelyanov static int sysctl_ipfrag_max_dist __read_mostly = 64; 5689cee8b1SHerbert Xu 571da177e4SLinus Torvalds struct ipfrag_skb_cb 581da177e4SLinus Torvalds { 591da177e4SLinus Torvalds struct inet_skb_parm h; 601da177e4SLinus Torvalds int offset; 611da177e4SLinus Torvalds }; 621da177e4SLinus Torvalds 631da177e4SLinus Torvalds #define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb)) 641da177e4SLinus Torvalds 651da177e4SLinus Torvalds /* Describe an entry in the "incomplete datagrams" queue. */ 661da177e4SLinus Torvalds struct ipq { 675ab11c98SPavel Emelyanov struct inet_frag_queue q; 685ab11c98SPavel Emelyanov 691da177e4SLinus Torvalds u32 user; 7018277770SAl Viro __be32 saddr; 7118277770SAl Viro __be32 daddr; 7218277770SAl Viro __be16 id; 731da177e4SLinus Torvalds u8 protocol; 746623e3b2SEric Dumazet u8 ecn; /* RFC3168 support */ 7589cee8b1SHerbert Xu int iif; 7689cee8b1SHerbert Xu unsigned int rid; 7789cee8b1SHerbert Xu struct inet_peer *peer; 781da177e4SLinus Torvalds }; 791da177e4SLinus Torvalds 805173cc05SEric Dumazet /* RFC 3168 support : 815173cc05SEric Dumazet * We want to check ECN values of all fragments, do detect invalid combinations. 825173cc05SEric Dumazet * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value. 835173cc05SEric Dumazet */ 841d1652cbSDavid S. Miller #define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */ 851d1652cbSDavid S. Miller #define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */ 861d1652cbSDavid S. Miller #define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */ 871d1652cbSDavid S. Miller #define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */ 886623e3b2SEric Dumazet 896623e3b2SEric Dumazet static inline u8 ip4_frag_ecn(u8 tos) 906623e3b2SEric Dumazet { 915173cc05SEric Dumazet return 1 << (tos & INET_ECN_MASK); 926623e3b2SEric Dumazet } 936623e3b2SEric Dumazet 945173cc05SEric Dumazet /* Given the OR values of all fragments, apply RFC 3168 5.3 requirements 955173cc05SEric Dumazet * Value : 0xff if frame should be dropped. 965173cc05SEric Dumazet * 0 or INET_ECN_CE value, to be ORed in to final iph->tos field 975173cc05SEric Dumazet */ 985173cc05SEric Dumazet static const u8 ip4_frag_ecn_table[16] = { 995173cc05SEric Dumazet /* at least one fragment had CE, and others ECT_0 or ECT_1 */ 1005173cc05SEric Dumazet [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = INET_ECN_CE, 1015173cc05SEric Dumazet [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = INET_ECN_CE, 1025173cc05SEric Dumazet [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = INET_ECN_CE, 1035173cc05SEric Dumazet 1045173cc05SEric Dumazet /* invalid combinations : drop frame */ 1055173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff, 1065173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff, 1075173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff, 1085173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff, 1095173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff, 1105173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff, 1115173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff, 1125173cc05SEric Dumazet }; 1135173cc05SEric Dumazet 1147eb95156SPavel Emelyanov static struct inet_frags ip4_frags; 1151da177e4SLinus Torvalds 116e5a2bb84SPavel Emelyanov int ip_frag_nqueues(struct net *net) 1177eb95156SPavel Emelyanov { 118e5a2bb84SPavel Emelyanov return net->ipv4.frags.nqueues; 1197eb95156SPavel Emelyanov } 1201da177e4SLinus Torvalds 1216ddc0822SPavel Emelyanov int ip_frag_mem(struct net *net) 1227eb95156SPavel Emelyanov { 1236ddc0822SPavel Emelyanov return atomic_read(&net->ipv4.frags.mem); 1247eb95156SPavel Emelyanov } 1251da177e4SLinus Torvalds 1261706d587SHerbert Xu static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 1271706d587SHerbert Xu struct net_device *dev); 1281706d587SHerbert Xu 129c6fda282SPavel Emelyanov struct ip4_create_arg { 130c6fda282SPavel Emelyanov struct iphdr *iph; 131c6fda282SPavel Emelyanov u32 user; 132c6fda282SPavel Emelyanov }; 133c6fda282SPavel Emelyanov 13418277770SAl Viro static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot) 1351da177e4SLinus Torvalds { 13618277770SAl Viro return jhash_3words((__force u32)id << 16 | prot, 13718277770SAl Viro (__force u32)saddr, (__force u32)daddr, 1387eb95156SPavel Emelyanov ip4_frags.rnd) & (INETFRAGS_HASHSZ - 1); 1391da177e4SLinus Torvalds } 1401da177e4SLinus Torvalds 141321a3a99SPavel Emelyanov static unsigned int ip4_hashfn(struct inet_frag_queue *q) 1421da177e4SLinus Torvalds { 143321a3a99SPavel Emelyanov struct ipq *ipq; 1441da177e4SLinus Torvalds 145321a3a99SPavel Emelyanov ipq = container_of(q, struct ipq, q); 146321a3a99SPavel Emelyanov return ipqhashfn(ipq->id, ipq->saddr, ipq->daddr, ipq->protocol); 1471da177e4SLinus Torvalds } 1481da177e4SLinus Torvalds 149abd6523dSPavel Emelyanov static int ip4_frag_match(struct inet_frag_queue *q, void *a) 150abd6523dSPavel Emelyanov { 151abd6523dSPavel Emelyanov struct ipq *qp; 152abd6523dSPavel Emelyanov struct ip4_create_arg *arg = a; 153abd6523dSPavel Emelyanov 154abd6523dSPavel Emelyanov qp = container_of(q, struct ipq, q); 155a02cec21SEric Dumazet return qp->id == arg->iph->id && 156abd6523dSPavel Emelyanov qp->saddr == arg->iph->saddr && 157abd6523dSPavel Emelyanov qp->daddr == arg->iph->daddr && 158abd6523dSPavel Emelyanov qp->protocol == arg->iph->protocol && 159a02cec21SEric Dumazet qp->user == arg->user; 160abd6523dSPavel Emelyanov } 161abd6523dSPavel Emelyanov 1621da177e4SLinus Torvalds /* Memory Tracking Functions. */ 163a95d8c88SEric Dumazet static void frag_kfree_skb(struct netns_frags *nf, struct sk_buff *skb) 1641da177e4SLinus Torvalds { 1656ddc0822SPavel Emelyanov atomic_sub(skb->truesize, &nf->mem); 1661da177e4SLinus Torvalds kfree_skb(skb); 1671da177e4SLinus Torvalds } 1681da177e4SLinus Torvalds 169c6fda282SPavel Emelyanov static void ip4_frag_init(struct inet_frag_queue *q, void *a) 170c6fda282SPavel Emelyanov { 171c6fda282SPavel Emelyanov struct ipq *qp = container_of(q, struct ipq, q); 172c6fda282SPavel Emelyanov struct ip4_create_arg *arg = a; 173c6fda282SPavel Emelyanov 174c6fda282SPavel Emelyanov qp->protocol = arg->iph->protocol; 175c6fda282SPavel Emelyanov qp->id = arg->iph->id; 1766623e3b2SEric Dumazet qp->ecn = ip4_frag_ecn(arg->iph->tos); 177c6fda282SPavel Emelyanov qp->saddr = arg->iph->saddr; 178c6fda282SPavel Emelyanov qp->daddr = arg->iph->daddr; 179c6fda282SPavel Emelyanov qp->user = arg->user; 180c6fda282SPavel Emelyanov qp->peer = sysctl_ipfrag_max_dist ? 181b534ecf1SDavid S. Miller inet_getpeer_v4(arg->iph->saddr, 1) : NULL; 182c6fda282SPavel Emelyanov } 183c6fda282SPavel Emelyanov 1841e4b8287SPavel Emelyanov static __inline__ void ip4_frag_free(struct inet_frag_queue *q) 1851da177e4SLinus Torvalds { 1861e4b8287SPavel Emelyanov struct ipq *qp; 1871e4b8287SPavel Emelyanov 1881e4b8287SPavel Emelyanov qp = container_of(q, struct ipq, q); 1891e4b8287SPavel Emelyanov if (qp->peer) 1901e4b8287SPavel Emelyanov inet_putpeer(qp->peer); 1911da177e4SLinus Torvalds } 1921da177e4SLinus Torvalds 1931da177e4SLinus Torvalds 1941da177e4SLinus Torvalds /* Destruction primitives. */ 1951da177e4SLinus Torvalds 1964b6cb5d8SPavel Emelyanov static __inline__ void ipq_put(struct ipq *ipq) 1971da177e4SLinus Torvalds { 198762cc408SPavel Emelyanov inet_frag_put(&ipq->q, &ip4_frags); 1991da177e4SLinus Torvalds } 2001da177e4SLinus Torvalds 2011da177e4SLinus Torvalds /* Kill ipq entry. It is not destroyed immediately, 2021da177e4SLinus Torvalds * because caller (and someone more) holds reference count. 2031da177e4SLinus Torvalds */ 2041da177e4SLinus Torvalds static void ipq_kill(struct ipq *ipq) 2051da177e4SLinus Torvalds { 206277e650dSPavel Emelyanov inet_frag_kill(&ipq->q, &ip4_frags); 2071da177e4SLinus Torvalds } 2081da177e4SLinus Torvalds 2091da177e4SLinus Torvalds /* Memory limiting on fragments. Evictor trashes the oldest 2101da177e4SLinus Torvalds * fragment queue until we are back under the threshold. 2111da177e4SLinus Torvalds */ 2126ddc0822SPavel Emelyanov static void ip_evictor(struct net *net) 2131da177e4SLinus Torvalds { 2148e7999c4SPavel Emelyanov int evicted; 2151da177e4SLinus Torvalds 2166ddc0822SPavel Emelyanov evicted = inet_frag_evictor(&net->ipv4.frags, &ip4_frags); 2178e7999c4SPavel Emelyanov if (evicted) 218c5346fe3SPavel Emelyanov IP_ADD_STATS_BH(net, IPSTATS_MIB_REASMFAILS, evicted); 2191da177e4SLinus Torvalds } 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvalds /* 2221da177e4SLinus Torvalds * Oops, a fragment queue timed out. Kill it and send an ICMP reply. 2231da177e4SLinus Torvalds */ 2241da177e4SLinus Torvalds static void ip_expire(unsigned long arg) 2251da177e4SLinus Torvalds { 226e521db9dSPavel Emelyanov struct ipq *qp; 22784a3aa00SPavel Emelyanov struct net *net; 228e521db9dSPavel Emelyanov 229e521db9dSPavel Emelyanov qp = container_of((struct inet_frag_queue *) arg, struct ipq, q); 23084a3aa00SPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 2311da177e4SLinus Torvalds 2325ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 2331da177e4SLinus Torvalds 234bc578a54SJoe Perches if (qp->q.last_in & INET_FRAG_COMPLETE) 2351da177e4SLinus Torvalds goto out; 2361da177e4SLinus Torvalds 2371da177e4SLinus Torvalds ipq_kill(qp); 2381da177e4SLinus Torvalds 2397c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMTIMEOUT); 2407c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 2411da177e4SLinus Torvalds 242bc578a54SJoe Perches if ((qp->q.last_in & INET_FRAG_FIRST_IN) && qp->q.fragments != NULL) { 2435ab11c98SPavel Emelyanov struct sk_buff *head = qp->q.fragments; 24464f3b9e2SEric Dumazet const struct iphdr *iph; 24564f3b9e2SEric Dumazet int err; 246cb84663eSDenis V. Lunev 24769df9d59SEric Dumazet rcu_read_lock(); 24869df9d59SEric Dumazet head->dev = dev_get_by_index_rcu(net, qp->iif); 249e9017b55SShan Wei if (!head->dev) 250e9017b55SShan Wei goto out_rcu_unlock; 251e9017b55SShan Wei 25264f3b9e2SEric Dumazet /* skb dst is stale, drop it, and perform route lookup again */ 25364f3b9e2SEric Dumazet skb_dst_drop(head); 25464f3b9e2SEric Dumazet iph = ip_hdr(head); 25564f3b9e2SEric Dumazet err = ip_route_input_noref(head, iph->daddr, iph->saddr, 256e9017b55SShan Wei iph->tos, head->dev); 25764f3b9e2SEric Dumazet if (err) 258e9017b55SShan Wei goto out_rcu_unlock; 259e9017b55SShan Wei 260e9017b55SShan Wei /* 261e9017b55SShan Wei * Only an end host needs to send an ICMP 262e9017b55SShan Wei * "Fragment Reassembly Timeout" message, per RFC792. 263e9017b55SShan Wei */ 264595fc71bSDavid S. Miller if (qp->user == IP_DEFRAG_AF_PACKET || 265595fc71bSDavid S. Miller (qp->user == IP_DEFRAG_CONNTRACK_IN && 266595fc71bSDavid S. Miller skb_rtable(head)->rt_type != RTN_LOCAL)) 267e9017b55SShan Wei goto out_rcu_unlock; 268e9017b55SShan Wei 269e9017b55SShan Wei 270e9017b55SShan Wei /* Send an ICMP "Fragment Reassembly Timeout" message. */ 271e9017b55SShan Wei icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); 272e9017b55SShan Wei out_rcu_unlock: 273e9017b55SShan Wei rcu_read_unlock(); 274d1c9ae6dSPatrick McHardy } 2751da177e4SLinus Torvalds out: 2765ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 2774b6cb5d8SPavel Emelyanov ipq_put(qp); 2781da177e4SLinus Torvalds } 2791da177e4SLinus Torvalds 280abd6523dSPavel Emelyanov /* Find the correct entry in the "incomplete datagrams" queue for 281abd6523dSPavel Emelyanov * this IP datagram, and create new one, if nothing is found. 282abd6523dSPavel Emelyanov */ 283ac18e750SPavel Emelyanov static inline struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user) 2841da177e4SLinus Torvalds { 285c6fda282SPavel Emelyanov struct inet_frag_queue *q; 286c6fda282SPavel Emelyanov struct ip4_create_arg arg; 287abd6523dSPavel Emelyanov unsigned int hash; 2881da177e4SLinus Torvalds 289c6fda282SPavel Emelyanov arg.iph = iph; 290c6fda282SPavel Emelyanov arg.user = user; 2919a375803SPavel Emelyanov 2929a375803SPavel Emelyanov read_lock(&ip4_frags.lock); 293abd6523dSPavel Emelyanov hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol); 294c6fda282SPavel Emelyanov 295ac18e750SPavel Emelyanov q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash); 296c6fda282SPavel Emelyanov if (q == NULL) 2971da177e4SLinus Torvalds goto out_nomem; 2981da177e4SLinus Torvalds 299c6fda282SPavel Emelyanov return container_of(q, struct ipq, q); 3001da177e4SLinus Torvalds 3011da177e4SLinus Torvalds out_nomem: 30264ce2073SPatrick McHardy LIMIT_NETDEBUG(KERN_ERR "ip_frag_create: no memory left !\n"); 3031da177e4SLinus Torvalds return NULL; 3041da177e4SLinus Torvalds } 3051da177e4SLinus Torvalds 30689cee8b1SHerbert Xu /* Is the fragment too far ahead to be part of ipq? */ 30789cee8b1SHerbert Xu static inline int ip_frag_too_far(struct ipq *qp) 30889cee8b1SHerbert Xu { 30989cee8b1SHerbert Xu struct inet_peer *peer = qp->peer; 31089cee8b1SHerbert Xu unsigned int max = sysctl_ipfrag_max_dist; 31189cee8b1SHerbert Xu unsigned int start, end; 31289cee8b1SHerbert Xu 31389cee8b1SHerbert Xu int rc; 31489cee8b1SHerbert Xu 31589cee8b1SHerbert Xu if (!peer || !max) 31689cee8b1SHerbert Xu return 0; 31789cee8b1SHerbert Xu 31889cee8b1SHerbert Xu start = qp->rid; 31989cee8b1SHerbert Xu end = atomic_inc_return(&peer->rid); 32089cee8b1SHerbert Xu qp->rid = end; 32189cee8b1SHerbert Xu 3225ab11c98SPavel Emelyanov rc = qp->q.fragments && (end - start) > max; 32389cee8b1SHerbert Xu 32489cee8b1SHerbert Xu if (rc) { 3257c73a6faSPavel Emelyanov struct net *net; 3267c73a6faSPavel Emelyanov 3277c73a6faSPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 3287c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 32989cee8b1SHerbert Xu } 33089cee8b1SHerbert Xu 33189cee8b1SHerbert Xu return rc; 33289cee8b1SHerbert Xu } 33389cee8b1SHerbert Xu 33489cee8b1SHerbert Xu static int ip_frag_reinit(struct ipq *qp) 33589cee8b1SHerbert Xu { 33689cee8b1SHerbert Xu struct sk_buff *fp; 33789cee8b1SHerbert Xu 338b2fd5321SPavel Emelyanov if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) { 3395ab11c98SPavel Emelyanov atomic_inc(&qp->q.refcnt); 34089cee8b1SHerbert Xu return -ETIMEDOUT; 34189cee8b1SHerbert Xu } 34289cee8b1SHerbert Xu 3435ab11c98SPavel Emelyanov fp = qp->q.fragments; 34489cee8b1SHerbert Xu do { 34589cee8b1SHerbert Xu struct sk_buff *xp = fp->next; 346a95d8c88SEric Dumazet frag_kfree_skb(qp->q.net, fp); 34789cee8b1SHerbert Xu fp = xp; 34889cee8b1SHerbert Xu } while (fp); 34989cee8b1SHerbert Xu 3505ab11c98SPavel Emelyanov qp->q.last_in = 0; 3515ab11c98SPavel Emelyanov qp->q.len = 0; 3525ab11c98SPavel Emelyanov qp->q.meat = 0; 3535ab11c98SPavel Emelyanov qp->q.fragments = NULL; 354d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 35589cee8b1SHerbert Xu qp->iif = 0; 3566623e3b2SEric Dumazet qp->ecn = 0; 35789cee8b1SHerbert Xu 35889cee8b1SHerbert Xu return 0; 35989cee8b1SHerbert Xu } 36089cee8b1SHerbert Xu 3611da177e4SLinus Torvalds /* Add new segment to existing queue. */ 3621706d587SHerbert Xu static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) 3631da177e4SLinus Torvalds { 3641da177e4SLinus Torvalds struct sk_buff *prev, *next; 3651706d587SHerbert Xu struct net_device *dev; 3661da177e4SLinus Torvalds int flags, offset; 3671da177e4SLinus Torvalds int ihl, end; 3681706d587SHerbert Xu int err = -ENOENT; 3696623e3b2SEric Dumazet u8 ecn; 3701da177e4SLinus Torvalds 371bc578a54SJoe Perches if (qp->q.last_in & INET_FRAG_COMPLETE) 3721da177e4SLinus Torvalds goto err; 3731da177e4SLinus Torvalds 37489cee8b1SHerbert Xu if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && 3751706d587SHerbert Xu unlikely(ip_frag_too_far(qp)) && 3761706d587SHerbert Xu unlikely(err = ip_frag_reinit(qp))) { 37789cee8b1SHerbert Xu ipq_kill(qp); 37889cee8b1SHerbert Xu goto err; 37989cee8b1SHerbert Xu } 38089cee8b1SHerbert Xu 3816623e3b2SEric Dumazet ecn = ip4_frag_ecn(ip_hdr(skb)->tos); 382eddc9ec5SArnaldo Carvalho de Melo offset = ntohs(ip_hdr(skb)->frag_off); 3831da177e4SLinus Torvalds flags = offset & ~IP_OFFSET; 3841da177e4SLinus Torvalds offset &= IP_OFFSET; 3851da177e4SLinus Torvalds offset <<= 3; /* offset is in 8-byte chunks */ 386c9bdd4b5SArnaldo Carvalho de Melo ihl = ip_hdrlen(skb); 3871da177e4SLinus Torvalds 3881da177e4SLinus Torvalds /* Determine the position of this fragment. */ 3891da177e4SLinus Torvalds end = offset + skb->len - ihl; 3901706d587SHerbert Xu err = -EINVAL; 3911da177e4SLinus Torvalds 3921da177e4SLinus Torvalds /* Is this the final fragment? */ 3931da177e4SLinus Torvalds if ((flags & IP_MF) == 0) { 3941da177e4SLinus Torvalds /* If we already have some bits beyond end 39542b2aa86SJustin P. Mattock * or have different end, the segment is corrupted. 3961da177e4SLinus Torvalds */ 3975ab11c98SPavel Emelyanov if (end < qp->q.len || 398bc578a54SJoe Perches ((qp->q.last_in & INET_FRAG_LAST_IN) && end != qp->q.len)) 3991da177e4SLinus Torvalds goto err; 400bc578a54SJoe Perches qp->q.last_in |= INET_FRAG_LAST_IN; 4015ab11c98SPavel Emelyanov qp->q.len = end; 4021da177e4SLinus Torvalds } else { 4031da177e4SLinus Torvalds if (end&7) { 4041da177e4SLinus Torvalds end &= ~7; 4051da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 4061da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 4071da177e4SLinus Torvalds } 4085ab11c98SPavel Emelyanov if (end > qp->q.len) { 4091da177e4SLinus Torvalds /* Some bits beyond end -> corruption. */ 410bc578a54SJoe Perches if (qp->q.last_in & INET_FRAG_LAST_IN) 4111da177e4SLinus Torvalds goto err; 4125ab11c98SPavel Emelyanov qp->q.len = end; 4131da177e4SLinus Torvalds } 4141da177e4SLinus Torvalds } 4151da177e4SLinus Torvalds if (end == offset) 4161da177e4SLinus Torvalds goto err; 4171da177e4SLinus Torvalds 4181706d587SHerbert Xu err = -ENOMEM; 4191da177e4SLinus Torvalds if (pskb_pull(skb, ihl) == NULL) 4201da177e4SLinus Torvalds goto err; 4211706d587SHerbert Xu 4221706d587SHerbert Xu err = pskb_trim_rcsum(skb, end - offset); 4231706d587SHerbert Xu if (err) 4241da177e4SLinus Torvalds goto err; 4251da177e4SLinus Torvalds 4261da177e4SLinus Torvalds /* Find out which fragments are in front and at the back of us 4271da177e4SLinus Torvalds * in the chain of fragments so far. We must know where to put 4281da177e4SLinus Torvalds * this fragment, right? 4291da177e4SLinus Torvalds */ 430d6bebca9SChangli Gao prev = qp->q.fragments_tail; 431d6bebca9SChangli Gao if (!prev || FRAG_CB(prev)->offset < offset) { 432d6bebca9SChangli Gao next = NULL; 433d6bebca9SChangli Gao goto found; 434d6bebca9SChangli Gao } 4351da177e4SLinus Torvalds prev = NULL; 4365ab11c98SPavel Emelyanov for (next = qp->q.fragments; next != NULL; next = next->next) { 4371da177e4SLinus Torvalds if (FRAG_CB(next)->offset >= offset) 4381da177e4SLinus Torvalds break; /* bingo! */ 4391da177e4SLinus Torvalds prev = next; 4401da177e4SLinus Torvalds } 4411da177e4SLinus Torvalds 442d6bebca9SChangli Gao found: 4431da177e4SLinus Torvalds /* We found where to put this one. Check for overlap with 4441da177e4SLinus Torvalds * preceding fragment, and, if needed, align things so that 4451da177e4SLinus Torvalds * any overlaps are eliminated. 4461da177e4SLinus Torvalds */ 4471da177e4SLinus Torvalds if (prev) { 4481da177e4SLinus Torvalds int i = (FRAG_CB(prev)->offset + prev->len) - offset; 4491da177e4SLinus Torvalds 4501da177e4SLinus Torvalds if (i > 0) { 4511da177e4SLinus Torvalds offset += i; 4521706d587SHerbert Xu err = -EINVAL; 4531da177e4SLinus Torvalds if (end <= offset) 4541da177e4SLinus Torvalds goto err; 4551706d587SHerbert Xu err = -ENOMEM; 4561da177e4SLinus Torvalds if (!pskb_pull(skb, i)) 4571da177e4SLinus Torvalds goto err; 4581da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 4591da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 4601da177e4SLinus Torvalds } 4611da177e4SLinus Torvalds } 4621da177e4SLinus Torvalds 4631706d587SHerbert Xu err = -ENOMEM; 4641706d587SHerbert Xu 4651da177e4SLinus Torvalds while (next && FRAG_CB(next)->offset < end) { 4661da177e4SLinus Torvalds int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */ 4671da177e4SLinus Torvalds 4681da177e4SLinus Torvalds if (i < next->len) { 4691da177e4SLinus Torvalds /* Eat head of the next overlapped fragment 4701da177e4SLinus Torvalds * and leave the loop. The next ones cannot overlap. 4711da177e4SLinus Torvalds */ 4721da177e4SLinus Torvalds if (!pskb_pull(next, i)) 4731da177e4SLinus Torvalds goto err; 4741da177e4SLinus Torvalds FRAG_CB(next)->offset += i; 4755ab11c98SPavel Emelyanov qp->q.meat -= i; 4761da177e4SLinus Torvalds if (next->ip_summed != CHECKSUM_UNNECESSARY) 4771da177e4SLinus Torvalds next->ip_summed = CHECKSUM_NONE; 4781da177e4SLinus Torvalds break; 4791da177e4SLinus Torvalds } else { 4801da177e4SLinus Torvalds struct sk_buff *free_it = next; 4811da177e4SLinus Torvalds 48247c6bf77SPeter Zijlstra /* Old fragment is completely overridden with 4831da177e4SLinus Torvalds * new one drop it. 4841da177e4SLinus Torvalds */ 4851da177e4SLinus Torvalds next = next->next; 4861da177e4SLinus Torvalds 4871da177e4SLinus Torvalds if (prev) 4881da177e4SLinus Torvalds prev->next = next; 4891da177e4SLinus Torvalds else 4905ab11c98SPavel Emelyanov qp->q.fragments = next; 4911da177e4SLinus Torvalds 4925ab11c98SPavel Emelyanov qp->q.meat -= free_it->len; 493a95d8c88SEric Dumazet frag_kfree_skb(qp->q.net, free_it); 4941da177e4SLinus Torvalds } 4951da177e4SLinus Torvalds } 4961da177e4SLinus Torvalds 4971da177e4SLinus Torvalds FRAG_CB(skb)->offset = offset; 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds /* Insert this fragment in the chain of fragments. */ 5001da177e4SLinus Torvalds skb->next = next; 501d6bebca9SChangli Gao if (!next) 502d6bebca9SChangli Gao qp->q.fragments_tail = skb; 5031da177e4SLinus Torvalds if (prev) 5041da177e4SLinus Torvalds prev->next = skb; 5051da177e4SLinus Torvalds else 5065ab11c98SPavel Emelyanov qp->q.fragments = skb; 5071da177e4SLinus Torvalds 5081706d587SHerbert Xu dev = skb->dev; 5091706d587SHerbert Xu if (dev) { 5101706d587SHerbert Xu qp->iif = dev->ifindex; 5111da177e4SLinus Torvalds skb->dev = NULL; 5121706d587SHerbert Xu } 5135ab11c98SPavel Emelyanov qp->q.stamp = skb->tstamp; 5145ab11c98SPavel Emelyanov qp->q.meat += skb->len; 5156623e3b2SEric Dumazet qp->ecn |= ecn; 5166ddc0822SPavel Emelyanov atomic_add(skb->truesize, &qp->q.net->mem); 5171da177e4SLinus Torvalds if (offset == 0) 518bc578a54SJoe Perches qp->q.last_in |= INET_FRAG_FIRST_IN; 5191da177e4SLinus Torvalds 520bc578a54SJoe Perches if (qp->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && 521bc578a54SJoe Perches qp->q.meat == qp->q.len) 5221706d587SHerbert Xu return ip_frag_reasm(qp, prev, dev); 5231706d587SHerbert Xu 5247eb95156SPavel Emelyanov write_lock(&ip4_frags.lock); 5253140c25cSPavel Emelyanov list_move_tail(&qp->q.lru_list, &qp->q.net->lru_list); 5267eb95156SPavel Emelyanov write_unlock(&ip4_frags.lock); 5271706d587SHerbert Xu return -EINPROGRESS; 5281da177e4SLinus Torvalds 5291da177e4SLinus Torvalds err: 5301da177e4SLinus Torvalds kfree_skb(skb); 5311706d587SHerbert Xu return err; 5321da177e4SLinus Torvalds } 5331da177e4SLinus Torvalds 5341da177e4SLinus Torvalds 5351da177e4SLinus Torvalds /* Build a new IP datagram from all its fragments. */ 5361da177e4SLinus Torvalds 5371706d587SHerbert Xu static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 5381706d587SHerbert Xu struct net_device *dev) 5391da177e4SLinus Torvalds { 5402bad35b7SJorge Boncompte [DTI2] struct net *net = container_of(qp->q.net, struct net, ipv4.frags); 5411da177e4SLinus Torvalds struct iphdr *iph; 5425ab11c98SPavel Emelyanov struct sk_buff *fp, *head = qp->q.fragments; 5431da177e4SLinus Torvalds int len; 5441da177e4SLinus Torvalds int ihlen; 5451706d587SHerbert Xu int err; 5465173cc05SEric Dumazet u8 ecn; 5471da177e4SLinus Torvalds 5481da177e4SLinus Torvalds ipq_kill(qp); 5491da177e4SLinus Torvalds 5505173cc05SEric Dumazet ecn = ip4_frag_ecn_table[qp->ecn]; 5515173cc05SEric Dumazet if (unlikely(ecn == 0xff)) { 5525173cc05SEric Dumazet err = -EINVAL; 5535173cc05SEric Dumazet goto out_fail; 5545173cc05SEric Dumazet } 5551706d587SHerbert Xu /* Make the one we just received the head. */ 5561706d587SHerbert Xu if (prev) { 5571706d587SHerbert Xu head = prev->next; 5581706d587SHerbert Xu fp = skb_clone(head, GFP_ATOMIC); 5591706d587SHerbert Xu if (!fp) 5601706d587SHerbert Xu goto out_nomem; 5611706d587SHerbert Xu 5621706d587SHerbert Xu fp->next = head->next; 563d6bebca9SChangli Gao if (!fp->next) 564d6bebca9SChangli Gao qp->q.fragments_tail = fp; 5651706d587SHerbert Xu prev->next = fp; 5661706d587SHerbert Xu 5675ab11c98SPavel Emelyanov skb_morph(head, qp->q.fragments); 5685ab11c98SPavel Emelyanov head->next = qp->q.fragments->next; 5691706d587SHerbert Xu 5705ab11c98SPavel Emelyanov kfree_skb(qp->q.fragments); 5715ab11c98SPavel Emelyanov qp->q.fragments = head; 5721706d587SHerbert Xu } 5731706d587SHerbert Xu 574547b792cSIlpo Järvinen WARN_ON(head == NULL); 575547b792cSIlpo Järvinen WARN_ON(FRAG_CB(head)->offset != 0); 5761da177e4SLinus Torvalds 5771da177e4SLinus Torvalds /* Allocate a new buffer for the datagram. */ 578c9bdd4b5SArnaldo Carvalho de Melo ihlen = ip_hdrlen(head); 5795ab11c98SPavel Emelyanov len = ihlen + qp->q.len; 5801da177e4SLinus Torvalds 5811706d587SHerbert Xu err = -E2BIG; 5821da177e4SLinus Torvalds if (len > 65535) 5831da177e4SLinus Torvalds goto out_oversize; 5841da177e4SLinus Torvalds 5851da177e4SLinus Torvalds /* Head of list must not be cloned. */ 5861da177e4SLinus Torvalds if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) 5871da177e4SLinus Torvalds goto out_nomem; 5881da177e4SLinus Torvalds 5891da177e4SLinus Torvalds /* If the first fragment is fragmented itself, we split 5901da177e4SLinus Torvalds * it to two chunks: the first with data and paged part 5911da177e4SLinus Torvalds * and the second, holding only fragments. */ 59221dc3301SDavid S. Miller if (skb_has_frag_list(head)) { 5931da177e4SLinus Torvalds struct sk_buff *clone; 5941da177e4SLinus Torvalds int i, plen = 0; 5951da177e4SLinus Torvalds 5961da177e4SLinus Torvalds if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) 5971da177e4SLinus Torvalds goto out_nomem; 5981da177e4SLinus Torvalds clone->next = head->next; 5991da177e4SLinus Torvalds head->next = clone; 6001da177e4SLinus Torvalds skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 601d7fcf1a5SDavid S. Miller skb_frag_list_init(head); 6021da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(head)->nr_frags; i++) 6039e903e08SEric Dumazet plen += skb_frag_size(&skb_shinfo(head)->frags[i]); 6041da177e4SLinus Torvalds clone->len = clone->data_len = head->data_len - plen; 6051da177e4SLinus Torvalds head->data_len -= clone->len; 6061da177e4SLinus Torvalds head->len -= clone->len; 6071da177e4SLinus Torvalds clone->csum = 0; 6081da177e4SLinus Torvalds clone->ip_summed = head->ip_summed; 6096ddc0822SPavel Emelyanov atomic_add(clone->truesize, &qp->q.net->mem); 6101da177e4SLinus Torvalds } 6111da177e4SLinus Torvalds 6121da177e4SLinus Torvalds skb_shinfo(head)->frag_list = head->next; 613d56f90a7SArnaldo Carvalho de Melo skb_push(head, head->data - skb_network_header(head)); 6141da177e4SLinus Torvalds 6151da177e4SLinus Torvalds for (fp=head->next; fp; fp = fp->next) { 6161da177e4SLinus Torvalds head->data_len += fp->len; 6171da177e4SLinus Torvalds head->len += fp->len; 6181da177e4SLinus Torvalds if (head->ip_summed != fp->ip_summed) 6191da177e4SLinus Torvalds head->ip_summed = CHECKSUM_NONE; 62084fa7933SPatrick McHardy else if (head->ip_summed == CHECKSUM_COMPLETE) 6211da177e4SLinus Torvalds head->csum = csum_add(head->csum, fp->csum); 6221da177e4SLinus Torvalds head->truesize += fp->truesize; 6231da177e4SLinus Torvalds } 624d27f9b35SEric Dumazet atomic_sub(head->truesize, &qp->q.net->mem); 6251da177e4SLinus Torvalds 6261da177e4SLinus Torvalds head->next = NULL; 6271da177e4SLinus Torvalds head->dev = dev; 6285ab11c98SPavel Emelyanov head->tstamp = qp->q.stamp; 6291da177e4SLinus Torvalds 630eddc9ec5SArnaldo Carvalho de Melo iph = ip_hdr(head); 6311da177e4SLinus Torvalds iph->frag_off = 0; 6321da177e4SLinus Torvalds iph->tot_len = htons(len); 6335173cc05SEric Dumazet iph->tos |= ecn; 6342bad35b7SJorge Boncompte [DTI2] IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS); 6355ab11c98SPavel Emelyanov qp->q.fragments = NULL; 636d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 6371706d587SHerbert Xu return 0; 6381da177e4SLinus Torvalds 6391da177e4SLinus Torvalds out_nomem: 64064ce2073SPatrick McHardy LIMIT_NETDEBUG(KERN_ERR "IP: queue_glue: no memory for gluing " 64164ce2073SPatrick McHardy "queue %p\n", qp); 64245542479SDavid Howells err = -ENOMEM; 6431da177e4SLinus Torvalds goto out_fail; 6441da177e4SLinus Torvalds out_oversize: 6451da177e4SLinus Torvalds if (net_ratelimit()) 646058bd4d2SJoe Perches pr_info("Oversized IP packet from %pI4\n", &qp->saddr); 6471da177e4SLinus Torvalds out_fail: 648bbf31bf1SDavid Ford IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 6491706d587SHerbert Xu return err; 6501da177e4SLinus Torvalds } 6511da177e4SLinus Torvalds 6521da177e4SLinus Torvalds /* Process an incoming IP datagram fragment. */ 653776c729eSHerbert Xu int ip_defrag(struct sk_buff *skb, u32 user) 6541da177e4SLinus Torvalds { 6551da177e4SLinus Torvalds struct ipq *qp; 656ac18e750SPavel Emelyanov struct net *net; 6571da177e4SLinus Torvalds 658adf30907SEric Dumazet net = skb->dev ? dev_net(skb->dev) : dev_net(skb_dst(skb)->dev); 6597c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMREQDS); 6601da177e4SLinus Torvalds 6611da177e4SLinus Torvalds /* Start by cleaning up the memory. */ 662e31e0bdcSPavel Emelyanov if (atomic_read(&net->ipv4.frags.mem) > net->ipv4.frags.high_thresh) 6636ddc0822SPavel Emelyanov ip_evictor(net); 6641da177e4SLinus Torvalds 6651da177e4SLinus Torvalds /* Lookup (or create) queue header */ 666ac18e750SPavel Emelyanov if ((qp = ip_find(net, ip_hdr(skb), user)) != NULL) { 6671706d587SHerbert Xu int ret; 6681da177e4SLinus Torvalds 6695ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 6701da177e4SLinus Torvalds 6711706d587SHerbert Xu ret = ip_frag_queue(qp, skb); 6721da177e4SLinus Torvalds 6735ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 6744b6cb5d8SPavel Emelyanov ipq_put(qp); 675776c729eSHerbert Xu return ret; 6761da177e4SLinus Torvalds } 6771da177e4SLinus Torvalds 6787c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 6791da177e4SLinus Torvalds kfree_skb(skb); 680776c729eSHerbert Xu return -ENOMEM; 6811da177e4SLinus Torvalds } 6824bc2f18bSEric Dumazet EXPORT_SYMBOL(ip_defrag); 6831da177e4SLinus Torvalds 684bc416d97SEric Dumazet struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) 685bc416d97SEric Dumazet { 686bc416d97SEric Dumazet const struct iphdr *iph; 687bc416d97SEric Dumazet u32 len; 688bc416d97SEric Dumazet 689bc416d97SEric Dumazet if (skb->protocol != htons(ETH_P_IP)) 690bc416d97SEric Dumazet return skb; 691bc416d97SEric Dumazet 692bc416d97SEric Dumazet if (!pskb_may_pull(skb, sizeof(struct iphdr))) 693bc416d97SEric Dumazet return skb; 694bc416d97SEric Dumazet 695bc416d97SEric Dumazet iph = ip_hdr(skb); 696bc416d97SEric Dumazet if (iph->ihl < 5 || iph->version != 4) 697bc416d97SEric Dumazet return skb; 698bc416d97SEric Dumazet if (!pskb_may_pull(skb, iph->ihl*4)) 699bc416d97SEric Dumazet return skb; 700bc416d97SEric Dumazet iph = ip_hdr(skb); 701bc416d97SEric Dumazet len = ntohs(iph->tot_len); 702bc416d97SEric Dumazet if (skb->len < len || len < (iph->ihl * 4)) 703bc416d97SEric Dumazet return skb; 704bc416d97SEric Dumazet 705bc416d97SEric Dumazet if (ip_is_fragment(ip_hdr(skb))) { 706bc416d97SEric Dumazet skb = skb_share_check(skb, GFP_ATOMIC); 707bc416d97SEric Dumazet if (skb) { 708bc416d97SEric Dumazet if (pskb_trim_rcsum(skb, len)) 709bc416d97SEric Dumazet return skb; 710bc416d97SEric Dumazet memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 711bc416d97SEric Dumazet if (ip_defrag(skb, user)) 712bc416d97SEric Dumazet return NULL; 713bc416d97SEric Dumazet skb->rxhash = 0; 714bc416d97SEric Dumazet } 715bc416d97SEric Dumazet } 716bc416d97SEric Dumazet return skb; 717bc416d97SEric Dumazet } 718bc416d97SEric Dumazet EXPORT_SYMBOL(ip_check_defrag); 719bc416d97SEric Dumazet 7208d8354d2SPavel Emelyanov #ifdef CONFIG_SYSCTL 7218d8354d2SPavel Emelyanov static int zero; 7228d8354d2SPavel Emelyanov 7230a64b4b8SPavel Emelyanov static struct ctl_table ip4_frags_ns_ctl_table[] = { 7248d8354d2SPavel Emelyanov { 7258d8354d2SPavel Emelyanov .procname = "ipfrag_high_thresh", 726e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.high_thresh, 7278d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7288d8354d2SPavel Emelyanov .mode = 0644, 7296d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec 7308d8354d2SPavel Emelyanov }, 7318d8354d2SPavel Emelyanov { 7328d8354d2SPavel Emelyanov .procname = "ipfrag_low_thresh", 733e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.low_thresh, 7348d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7358d8354d2SPavel Emelyanov .mode = 0644, 7366d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec 7378d8354d2SPavel Emelyanov }, 7388d8354d2SPavel Emelyanov { 7398d8354d2SPavel Emelyanov .procname = "ipfrag_time", 740b2fd5321SPavel Emelyanov .data = &init_net.ipv4.frags.timeout, 7418d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7428d8354d2SPavel Emelyanov .mode = 0644, 7436d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7448d8354d2SPavel Emelyanov }, 7457d291ebbSPavel Emelyanov { } 7467d291ebbSPavel Emelyanov }; 7477d291ebbSPavel Emelyanov 7487d291ebbSPavel Emelyanov static struct ctl_table ip4_frags_ctl_table[] = { 7498d8354d2SPavel Emelyanov { 7508d8354d2SPavel Emelyanov .procname = "ipfrag_secret_interval", 7513b4bc4a2SPavel Emelyanov .data = &ip4_frags.secret_interval, 7528d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7538d8354d2SPavel Emelyanov .mode = 0644, 7546d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7558d8354d2SPavel Emelyanov }, 7568d8354d2SPavel Emelyanov { 7578d8354d2SPavel Emelyanov .procname = "ipfrag_max_dist", 7588d8354d2SPavel Emelyanov .data = &sysctl_ipfrag_max_dist, 7598d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7608d8354d2SPavel Emelyanov .mode = 0644, 7616d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_minmax, 7628d8354d2SPavel Emelyanov .extra1 = &zero 7638d8354d2SPavel Emelyanov }, 7648d8354d2SPavel Emelyanov { } 7658d8354d2SPavel Emelyanov }; 7668d8354d2SPavel Emelyanov 7672c8c1e72SAlexey Dobriyan static int __net_init ip4_frags_ns_ctl_register(struct net *net) 7688d8354d2SPavel Emelyanov { 769e4a2d5c2SPavel Emelyanov struct ctl_table *table; 7708d8354d2SPavel Emelyanov struct ctl_table_header *hdr; 7718d8354d2SPavel Emelyanov 7720a64b4b8SPavel Emelyanov table = ip4_frags_ns_ctl_table; 77309ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) { 7740a64b4b8SPavel Emelyanov table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL); 775e4a2d5c2SPavel Emelyanov if (table == NULL) 776e4a2d5c2SPavel Emelyanov goto err_alloc; 777e4a2d5c2SPavel Emelyanov 778e31e0bdcSPavel Emelyanov table[0].data = &net->ipv4.frags.high_thresh; 779e31e0bdcSPavel Emelyanov table[1].data = &net->ipv4.frags.low_thresh; 780b2fd5321SPavel Emelyanov table[2].data = &net->ipv4.frags.timeout; 781e4a2d5c2SPavel Emelyanov } 782e4a2d5c2SPavel Emelyanov 783e4a2d5c2SPavel Emelyanov hdr = register_net_sysctl_table(net, net_ipv4_ctl_path, table); 784e4a2d5c2SPavel Emelyanov if (hdr == NULL) 785e4a2d5c2SPavel Emelyanov goto err_reg; 786e4a2d5c2SPavel Emelyanov 787e4a2d5c2SPavel Emelyanov net->ipv4.frags_hdr = hdr; 788e4a2d5c2SPavel Emelyanov return 0; 789e4a2d5c2SPavel Emelyanov 790e4a2d5c2SPavel Emelyanov err_reg: 79109ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) 792e4a2d5c2SPavel Emelyanov kfree(table); 793e4a2d5c2SPavel Emelyanov err_alloc: 794e4a2d5c2SPavel Emelyanov return -ENOMEM; 795e4a2d5c2SPavel Emelyanov } 796e4a2d5c2SPavel Emelyanov 7972c8c1e72SAlexey Dobriyan static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net) 798e4a2d5c2SPavel Emelyanov { 799e4a2d5c2SPavel Emelyanov struct ctl_table *table; 800e4a2d5c2SPavel Emelyanov 801e4a2d5c2SPavel Emelyanov table = net->ipv4.frags_hdr->ctl_table_arg; 802e4a2d5c2SPavel Emelyanov unregister_net_sysctl_table(net->ipv4.frags_hdr); 803e4a2d5c2SPavel Emelyanov kfree(table); 8048d8354d2SPavel Emelyanov } 8057d291ebbSPavel Emelyanov 8067d291ebbSPavel Emelyanov static void ip4_frags_ctl_register(void) 8077d291ebbSPavel Emelyanov { 8087d291ebbSPavel Emelyanov register_net_sysctl_rotable(net_ipv4_ctl_path, ip4_frags_ctl_table); 8097d291ebbSPavel Emelyanov } 8108d8354d2SPavel Emelyanov #else 8110a64b4b8SPavel Emelyanov static inline int ip4_frags_ns_ctl_register(struct net *net) 8128d8354d2SPavel Emelyanov { 8138d8354d2SPavel Emelyanov return 0; 8148d8354d2SPavel Emelyanov } 815e4a2d5c2SPavel Emelyanov 8160a64b4b8SPavel Emelyanov static inline void ip4_frags_ns_ctl_unregister(struct net *net) 817e4a2d5c2SPavel Emelyanov { 818e4a2d5c2SPavel Emelyanov } 8197d291ebbSPavel Emelyanov 8207d291ebbSPavel Emelyanov static inline void ip4_frags_ctl_register(void) 8217d291ebbSPavel Emelyanov { 8227d291ebbSPavel Emelyanov } 8238d8354d2SPavel Emelyanov #endif 8248d8354d2SPavel Emelyanov 8252c8c1e72SAlexey Dobriyan static int __net_init ipv4_frags_init_net(struct net *net) 8268d8354d2SPavel Emelyanov { 827b2fd5321SPavel Emelyanov /* 828e31e0bdcSPavel Emelyanov * Fragment cache limits. We will commit 256K at one time. Should we 829e31e0bdcSPavel Emelyanov * cross that limit we will prune down to 192K. This should cope with 830e31e0bdcSPavel Emelyanov * even the most extreme cases without allowing an attacker to 831e31e0bdcSPavel Emelyanov * measurably harm machine performance. 832e31e0bdcSPavel Emelyanov */ 833e31e0bdcSPavel Emelyanov net->ipv4.frags.high_thresh = 256 * 1024; 834e31e0bdcSPavel Emelyanov net->ipv4.frags.low_thresh = 192 * 1024; 835e31e0bdcSPavel Emelyanov /* 836b2fd5321SPavel Emelyanov * Important NOTE! Fragment queue must be destroyed before MSL expires. 837b2fd5321SPavel Emelyanov * RFC791 is wrong proposing to prolongate timer each fragment arrival 838b2fd5321SPavel Emelyanov * by TTL. 839b2fd5321SPavel Emelyanov */ 840b2fd5321SPavel Emelyanov net->ipv4.frags.timeout = IP_FRAG_TIME; 841b2fd5321SPavel Emelyanov 842e5a2bb84SPavel Emelyanov inet_frags_init_net(&net->ipv4.frags); 843e5a2bb84SPavel Emelyanov 8440a64b4b8SPavel Emelyanov return ip4_frags_ns_ctl_register(net); 8458d8354d2SPavel Emelyanov } 8468d8354d2SPavel Emelyanov 8472c8c1e72SAlexey Dobriyan static void __net_exit ipv4_frags_exit_net(struct net *net) 84881566e83SPavel Emelyanov { 8490a64b4b8SPavel Emelyanov ip4_frags_ns_ctl_unregister(net); 85081566e83SPavel Emelyanov inet_frags_exit_net(&net->ipv4.frags, &ip4_frags); 85181566e83SPavel Emelyanov } 85281566e83SPavel Emelyanov 85381566e83SPavel Emelyanov static struct pernet_operations ip4_frags_ops = { 85481566e83SPavel Emelyanov .init = ipv4_frags_init_net, 85581566e83SPavel Emelyanov .exit = ipv4_frags_exit_net, 85681566e83SPavel Emelyanov }; 85781566e83SPavel Emelyanov 858b7aa0bf7SEric Dumazet void __init ipfrag_init(void) 8591da177e4SLinus Torvalds { 8607d291ebbSPavel Emelyanov ip4_frags_ctl_register(); 86181566e83SPavel Emelyanov register_pernet_subsys(&ip4_frags_ops); 862321a3a99SPavel Emelyanov ip4_frags.hashfn = ip4_hashfn; 863c6fda282SPavel Emelyanov ip4_frags.constructor = ip4_frag_init; 8641e4b8287SPavel Emelyanov ip4_frags.destructor = ip4_frag_free; 8651e4b8287SPavel Emelyanov ip4_frags.skb_free = NULL; 8661e4b8287SPavel Emelyanov ip4_frags.qsize = sizeof(struct ipq); 867abd6523dSPavel Emelyanov ip4_frags.match = ip4_frag_match; 868e521db9dSPavel Emelyanov ip4_frags.frag_expire = ip_expire; 8693b4bc4a2SPavel Emelyanov ip4_frags.secret_interval = 10 * 60 * HZ; 8707eb95156SPavel Emelyanov inet_frags_init(&ip4_frags); 8711da177e4SLinus Torvalds } 872