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 23afd46503SJoe Perches #define pr_fmt(fmt) "IPv4: " fmt 24afd46503SJoe Perches 2589cee8b1SHerbert Xu #include <linux/compiler.h> 261da177e4SLinus Torvalds #include <linux/module.h> 271da177e4SLinus Torvalds #include <linux/types.h> 281da177e4SLinus Torvalds #include <linux/mm.h> 291da177e4SLinus Torvalds #include <linux/jiffies.h> 301da177e4SLinus Torvalds #include <linux/skbuff.h> 311da177e4SLinus Torvalds #include <linux/list.h> 321da177e4SLinus Torvalds #include <linux/ip.h> 331da177e4SLinus Torvalds #include <linux/icmp.h> 341da177e4SLinus Torvalds #include <linux/netdevice.h> 351da177e4SLinus Torvalds #include <linux/jhash.h> 361da177e4SLinus Torvalds #include <linux/random.h> 375a0e3ad6STejun Heo #include <linux/slab.h> 38e9017b55SShan Wei #include <net/route.h> 39e9017b55SShan Wei #include <net/dst.h> 401da177e4SLinus Torvalds #include <net/sock.h> 411da177e4SLinus Torvalds #include <net/ip.h> 421da177e4SLinus Torvalds #include <net/icmp.h> 431da177e4SLinus Torvalds #include <net/checksum.h> 4489cee8b1SHerbert Xu #include <net/inetpeer.h> 455ab11c98SPavel Emelyanov #include <net/inet_frag.h> 461da177e4SLinus Torvalds #include <linux/tcp.h> 471da177e4SLinus Torvalds #include <linux/udp.h> 481da177e4SLinus Torvalds #include <linux/inet.h> 491da177e4SLinus Torvalds #include <linux/netfilter_ipv4.h> 506623e3b2SEric Dumazet #include <net/inet_ecn.h> 511da177e4SLinus Torvalds 521da177e4SLinus Torvalds /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6 531da177e4SLinus Torvalds * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c 541da177e4SLinus Torvalds * as well. Or notify me, at least. --ANK 551da177e4SLinus Torvalds */ 561da177e4SLinus Torvalds 578d8354d2SPavel Emelyanov static int sysctl_ipfrag_max_dist __read_mostly = 64; 5889cee8b1SHerbert Xu 591da177e4SLinus Torvalds struct ipfrag_skb_cb 601da177e4SLinus Torvalds { 611da177e4SLinus Torvalds struct inet_skb_parm h; 621da177e4SLinus Torvalds int offset; 631da177e4SLinus Torvalds }; 641da177e4SLinus Torvalds 651da177e4SLinus Torvalds #define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb)) 661da177e4SLinus Torvalds 671da177e4SLinus Torvalds /* Describe an entry in the "incomplete datagrams" queue. */ 681da177e4SLinus Torvalds struct ipq { 695ab11c98SPavel Emelyanov struct inet_frag_queue q; 705ab11c98SPavel Emelyanov 711da177e4SLinus Torvalds u32 user; 7218277770SAl Viro __be32 saddr; 7318277770SAl Viro __be32 daddr; 7418277770SAl Viro __be16 id; 751da177e4SLinus Torvalds u8 protocol; 766623e3b2SEric Dumazet u8 ecn; /* RFC3168 support */ 7789cee8b1SHerbert Xu int iif; 7889cee8b1SHerbert Xu unsigned int rid; 7989cee8b1SHerbert Xu struct inet_peer *peer; 801da177e4SLinus Torvalds }; 811da177e4SLinus Torvalds 825173cc05SEric Dumazet /* RFC 3168 support : 835173cc05SEric Dumazet * We want to check ECN values of all fragments, do detect invalid combinations. 845173cc05SEric Dumazet * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value. 855173cc05SEric Dumazet */ 861d1652cbSDavid S. Miller #define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */ 871d1652cbSDavid S. Miller #define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */ 881d1652cbSDavid S. Miller #define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */ 891d1652cbSDavid S. Miller #define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */ 906623e3b2SEric Dumazet 916623e3b2SEric Dumazet static inline u8 ip4_frag_ecn(u8 tos) 926623e3b2SEric Dumazet { 935173cc05SEric Dumazet return 1 << (tos & INET_ECN_MASK); 946623e3b2SEric Dumazet } 956623e3b2SEric Dumazet 965173cc05SEric Dumazet /* Given the OR values of all fragments, apply RFC 3168 5.3 requirements 975173cc05SEric Dumazet * Value : 0xff if frame should be dropped. 985173cc05SEric Dumazet * 0 or INET_ECN_CE value, to be ORed in to final iph->tos field 995173cc05SEric Dumazet */ 1005173cc05SEric Dumazet static const u8 ip4_frag_ecn_table[16] = { 1015173cc05SEric Dumazet /* at least one fragment had CE, and others ECT_0 or ECT_1 */ 1025173cc05SEric Dumazet [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = INET_ECN_CE, 1035173cc05SEric Dumazet [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = INET_ECN_CE, 1045173cc05SEric Dumazet [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = INET_ECN_CE, 1055173cc05SEric Dumazet 1065173cc05SEric Dumazet /* invalid combinations : drop frame */ 1075173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff, 1085173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff, 1095173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff, 1105173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff, 1115173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff, 1125173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff, 1135173cc05SEric Dumazet [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff, 1145173cc05SEric Dumazet }; 1155173cc05SEric Dumazet 1167eb95156SPavel Emelyanov static struct inet_frags ip4_frags; 1171da177e4SLinus Torvalds 118e5a2bb84SPavel Emelyanov int ip_frag_nqueues(struct net *net) 1197eb95156SPavel Emelyanov { 120e5a2bb84SPavel Emelyanov return net->ipv4.frags.nqueues; 1217eb95156SPavel Emelyanov } 1221da177e4SLinus Torvalds 1236ddc0822SPavel Emelyanov int ip_frag_mem(struct net *net) 1247eb95156SPavel Emelyanov { 1256ddc0822SPavel Emelyanov return atomic_read(&net->ipv4.frags.mem); 1267eb95156SPavel Emelyanov } 1271da177e4SLinus Torvalds 1281706d587SHerbert Xu static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 1291706d587SHerbert Xu struct net_device *dev); 1301706d587SHerbert Xu 131c6fda282SPavel Emelyanov struct ip4_create_arg { 132c6fda282SPavel Emelyanov struct iphdr *iph; 133c6fda282SPavel Emelyanov u32 user; 134c6fda282SPavel Emelyanov }; 135c6fda282SPavel Emelyanov 13618277770SAl Viro static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot) 1371da177e4SLinus Torvalds { 13818277770SAl Viro return jhash_3words((__force u32)id << 16 | prot, 13918277770SAl Viro (__force u32)saddr, (__force u32)daddr, 1407eb95156SPavel Emelyanov ip4_frags.rnd) & (INETFRAGS_HASHSZ - 1); 1411da177e4SLinus Torvalds } 1421da177e4SLinus Torvalds 143321a3a99SPavel Emelyanov static unsigned int ip4_hashfn(struct inet_frag_queue *q) 1441da177e4SLinus Torvalds { 145321a3a99SPavel Emelyanov struct ipq *ipq; 1461da177e4SLinus Torvalds 147321a3a99SPavel Emelyanov ipq = container_of(q, struct ipq, q); 148321a3a99SPavel Emelyanov return ipqhashfn(ipq->id, ipq->saddr, ipq->daddr, ipq->protocol); 1491da177e4SLinus Torvalds } 1501da177e4SLinus Torvalds 151cbc264caSEric Dumazet static bool ip4_frag_match(struct inet_frag_queue *q, void *a) 152abd6523dSPavel Emelyanov { 153abd6523dSPavel Emelyanov struct ipq *qp; 154abd6523dSPavel Emelyanov struct ip4_create_arg *arg = a; 155abd6523dSPavel Emelyanov 156abd6523dSPavel Emelyanov qp = container_of(q, struct ipq, q); 157a02cec21SEric Dumazet return qp->id == arg->iph->id && 158abd6523dSPavel Emelyanov qp->saddr == arg->iph->saddr && 159abd6523dSPavel Emelyanov qp->daddr == arg->iph->daddr && 160abd6523dSPavel Emelyanov qp->protocol == arg->iph->protocol && 161a02cec21SEric Dumazet qp->user == arg->user; 162abd6523dSPavel Emelyanov } 163abd6523dSPavel Emelyanov 1641da177e4SLinus Torvalds /* Memory Tracking Functions. */ 165a95d8c88SEric Dumazet static void frag_kfree_skb(struct netns_frags *nf, struct sk_buff *skb) 1661da177e4SLinus Torvalds { 1676ddc0822SPavel Emelyanov atomic_sub(skb->truesize, &nf->mem); 1681da177e4SLinus Torvalds kfree_skb(skb); 1691da177e4SLinus Torvalds } 1701da177e4SLinus Torvalds 171c6fda282SPavel Emelyanov static void ip4_frag_init(struct inet_frag_queue *q, void *a) 172c6fda282SPavel Emelyanov { 173c6fda282SPavel Emelyanov struct ipq *qp = container_of(q, struct ipq, q); 17454db0cc2SGao feng struct netns_ipv4 *ipv4 = container_of(q->net, struct netns_ipv4, 17554db0cc2SGao feng frags); 17654db0cc2SGao feng struct net *net = container_of(ipv4, struct net, ipv4); 17754db0cc2SGao feng 178c6fda282SPavel Emelyanov struct ip4_create_arg *arg = a; 179c6fda282SPavel Emelyanov 180c6fda282SPavel Emelyanov qp->protocol = arg->iph->protocol; 181c6fda282SPavel Emelyanov qp->id = arg->iph->id; 1826623e3b2SEric Dumazet qp->ecn = ip4_frag_ecn(arg->iph->tos); 183c6fda282SPavel Emelyanov qp->saddr = arg->iph->saddr; 184c6fda282SPavel Emelyanov qp->daddr = arg->iph->daddr; 185c6fda282SPavel Emelyanov qp->user = arg->user; 186c6fda282SPavel Emelyanov qp->peer = sysctl_ipfrag_max_dist ? 187c0efc887SDavid S. Miller inet_getpeer_v4(net->ipv4.peers, arg->iph->saddr, 1) : NULL; 188c6fda282SPavel Emelyanov } 189c6fda282SPavel Emelyanov 1901e4b8287SPavel Emelyanov static __inline__ void ip4_frag_free(struct inet_frag_queue *q) 1911da177e4SLinus Torvalds { 1921e4b8287SPavel Emelyanov struct ipq *qp; 1931e4b8287SPavel Emelyanov 1941e4b8287SPavel Emelyanov qp = container_of(q, struct ipq, q); 1951e4b8287SPavel Emelyanov if (qp->peer) 1961e4b8287SPavel Emelyanov inet_putpeer(qp->peer); 1971da177e4SLinus Torvalds } 1981da177e4SLinus Torvalds 1991da177e4SLinus Torvalds 2001da177e4SLinus Torvalds /* Destruction primitives. */ 2011da177e4SLinus Torvalds 2024b6cb5d8SPavel Emelyanov static __inline__ void ipq_put(struct ipq *ipq) 2031da177e4SLinus Torvalds { 204762cc408SPavel Emelyanov inet_frag_put(&ipq->q, &ip4_frags); 2051da177e4SLinus Torvalds } 2061da177e4SLinus Torvalds 2071da177e4SLinus Torvalds /* Kill ipq entry. It is not destroyed immediately, 2081da177e4SLinus Torvalds * because caller (and someone more) holds reference count. 2091da177e4SLinus Torvalds */ 2101da177e4SLinus Torvalds static void ipq_kill(struct ipq *ipq) 2111da177e4SLinus Torvalds { 212277e650dSPavel Emelyanov inet_frag_kill(&ipq->q, &ip4_frags); 2131da177e4SLinus Torvalds } 2141da177e4SLinus Torvalds 2151da177e4SLinus Torvalds /* Memory limiting on fragments. Evictor trashes the oldest 2161da177e4SLinus Torvalds * fragment queue until we are back under the threshold. 2171da177e4SLinus Torvalds */ 2186ddc0822SPavel Emelyanov static void ip_evictor(struct net *net) 2191da177e4SLinus Torvalds { 2208e7999c4SPavel Emelyanov int evicted; 2211da177e4SLinus Torvalds 2226b102865SAmerigo Wang evicted = inet_frag_evictor(&net->ipv4.frags, &ip4_frags, false); 2238e7999c4SPavel Emelyanov if (evicted) 224c5346fe3SPavel Emelyanov IP_ADD_STATS_BH(net, IPSTATS_MIB_REASMFAILS, evicted); 2251da177e4SLinus Torvalds } 2261da177e4SLinus Torvalds 2271da177e4SLinus Torvalds /* 2281da177e4SLinus Torvalds * Oops, a fragment queue timed out. Kill it and send an ICMP reply. 2291da177e4SLinus Torvalds */ 2301da177e4SLinus Torvalds static void ip_expire(unsigned long arg) 2311da177e4SLinus Torvalds { 232e521db9dSPavel Emelyanov struct ipq *qp; 23384a3aa00SPavel Emelyanov struct net *net; 234e521db9dSPavel Emelyanov 235e521db9dSPavel Emelyanov qp = container_of((struct inet_frag_queue *) arg, struct ipq, q); 23684a3aa00SPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 2371da177e4SLinus Torvalds 2385ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 2391da177e4SLinus Torvalds 240bc578a54SJoe Perches if (qp->q.last_in & INET_FRAG_COMPLETE) 2411da177e4SLinus Torvalds goto out; 2421da177e4SLinus Torvalds 2431da177e4SLinus Torvalds ipq_kill(qp); 2441da177e4SLinus Torvalds 2457c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMTIMEOUT); 2467c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 2471da177e4SLinus Torvalds 248bc578a54SJoe Perches if ((qp->q.last_in & INET_FRAG_FIRST_IN) && qp->q.fragments != NULL) { 2495ab11c98SPavel Emelyanov struct sk_buff *head = qp->q.fragments; 25064f3b9e2SEric Dumazet const struct iphdr *iph; 25164f3b9e2SEric Dumazet int err; 252cb84663eSDenis V. Lunev 25369df9d59SEric Dumazet rcu_read_lock(); 25469df9d59SEric Dumazet head->dev = dev_get_by_index_rcu(net, qp->iif); 255e9017b55SShan Wei if (!head->dev) 256e9017b55SShan Wei goto out_rcu_unlock; 257e9017b55SShan Wei 25864f3b9e2SEric Dumazet /* skb dst is stale, drop it, and perform route lookup again */ 25964f3b9e2SEric Dumazet skb_dst_drop(head); 26064f3b9e2SEric Dumazet iph = ip_hdr(head); 261c6cffba4SDavid S. Miller err = ip_route_input_noref(head, iph->daddr, iph->saddr, 262c10237e0SDavid S. Miller iph->tos, head->dev); 26364f3b9e2SEric Dumazet if (err) 264e9017b55SShan Wei goto out_rcu_unlock; 265e9017b55SShan Wei 266e9017b55SShan Wei /* 267e9017b55SShan Wei * Only an end host needs to send an ICMP 268e9017b55SShan Wei * "Fragment Reassembly Timeout" message, per RFC792. 269e9017b55SShan Wei */ 270595fc71bSDavid S. Miller if (qp->user == IP_DEFRAG_AF_PACKET || 271595fc71bSDavid S. Miller (qp->user == IP_DEFRAG_CONNTRACK_IN && 272595fc71bSDavid S. Miller skb_rtable(head)->rt_type != RTN_LOCAL)) 273e9017b55SShan Wei goto out_rcu_unlock; 274e9017b55SShan Wei 275e9017b55SShan Wei 276e9017b55SShan Wei /* Send an ICMP "Fragment Reassembly Timeout" message. */ 277e9017b55SShan Wei icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); 278e9017b55SShan Wei out_rcu_unlock: 279e9017b55SShan Wei rcu_read_unlock(); 280d1c9ae6dSPatrick McHardy } 2811da177e4SLinus Torvalds out: 2825ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 2834b6cb5d8SPavel Emelyanov ipq_put(qp); 2841da177e4SLinus Torvalds } 2851da177e4SLinus Torvalds 286abd6523dSPavel Emelyanov /* Find the correct entry in the "incomplete datagrams" queue for 287abd6523dSPavel Emelyanov * this IP datagram, and create new one, if nothing is found. 288abd6523dSPavel Emelyanov */ 289ac18e750SPavel Emelyanov static inline struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user) 2901da177e4SLinus Torvalds { 291c6fda282SPavel Emelyanov struct inet_frag_queue *q; 292c6fda282SPavel Emelyanov struct ip4_create_arg arg; 293abd6523dSPavel Emelyanov unsigned int hash; 2941da177e4SLinus Torvalds 295c6fda282SPavel Emelyanov arg.iph = iph; 296c6fda282SPavel Emelyanov arg.user = user; 2979a375803SPavel Emelyanov 2989a375803SPavel Emelyanov read_lock(&ip4_frags.lock); 299abd6523dSPavel Emelyanov hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol); 300c6fda282SPavel Emelyanov 301ac18e750SPavel Emelyanov q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash); 302c6fda282SPavel Emelyanov if (q == NULL) 3031da177e4SLinus Torvalds goto out_nomem; 3041da177e4SLinus Torvalds 305c6fda282SPavel Emelyanov return container_of(q, struct ipq, q); 3061da177e4SLinus Torvalds 3071da177e4SLinus Torvalds out_nomem: 308afd46503SJoe Perches LIMIT_NETDEBUG(KERN_ERR pr_fmt("ip_frag_create: no memory left !\n")); 3091da177e4SLinus Torvalds return NULL; 3101da177e4SLinus Torvalds } 3111da177e4SLinus Torvalds 31289cee8b1SHerbert Xu /* Is the fragment too far ahead to be part of ipq? */ 31389cee8b1SHerbert Xu static inline int ip_frag_too_far(struct ipq *qp) 31489cee8b1SHerbert Xu { 31589cee8b1SHerbert Xu struct inet_peer *peer = qp->peer; 31689cee8b1SHerbert Xu unsigned int max = sysctl_ipfrag_max_dist; 31789cee8b1SHerbert Xu unsigned int start, end; 31889cee8b1SHerbert Xu 31989cee8b1SHerbert Xu int rc; 32089cee8b1SHerbert Xu 32189cee8b1SHerbert Xu if (!peer || !max) 32289cee8b1SHerbert Xu return 0; 32389cee8b1SHerbert Xu 32489cee8b1SHerbert Xu start = qp->rid; 32589cee8b1SHerbert Xu end = atomic_inc_return(&peer->rid); 32689cee8b1SHerbert Xu qp->rid = end; 32789cee8b1SHerbert Xu 3285ab11c98SPavel Emelyanov rc = qp->q.fragments && (end - start) > max; 32989cee8b1SHerbert Xu 33089cee8b1SHerbert Xu if (rc) { 3317c73a6faSPavel Emelyanov struct net *net; 3327c73a6faSPavel Emelyanov 3337c73a6faSPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 3347c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 33589cee8b1SHerbert Xu } 33689cee8b1SHerbert Xu 33789cee8b1SHerbert Xu return rc; 33889cee8b1SHerbert Xu } 33989cee8b1SHerbert Xu 34089cee8b1SHerbert Xu static int ip_frag_reinit(struct ipq *qp) 34189cee8b1SHerbert Xu { 34289cee8b1SHerbert Xu struct sk_buff *fp; 34389cee8b1SHerbert Xu 344b2fd5321SPavel Emelyanov if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) { 3455ab11c98SPavel Emelyanov atomic_inc(&qp->q.refcnt); 34689cee8b1SHerbert Xu return -ETIMEDOUT; 34789cee8b1SHerbert Xu } 34889cee8b1SHerbert Xu 3495ab11c98SPavel Emelyanov fp = qp->q.fragments; 35089cee8b1SHerbert Xu do { 35189cee8b1SHerbert Xu struct sk_buff *xp = fp->next; 352a95d8c88SEric Dumazet frag_kfree_skb(qp->q.net, fp); 35389cee8b1SHerbert Xu fp = xp; 35489cee8b1SHerbert Xu } while (fp); 35589cee8b1SHerbert Xu 3565ab11c98SPavel Emelyanov qp->q.last_in = 0; 3575ab11c98SPavel Emelyanov qp->q.len = 0; 3585ab11c98SPavel Emelyanov qp->q.meat = 0; 3595ab11c98SPavel Emelyanov qp->q.fragments = NULL; 360d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 36189cee8b1SHerbert Xu qp->iif = 0; 3626623e3b2SEric Dumazet qp->ecn = 0; 36389cee8b1SHerbert Xu 36489cee8b1SHerbert Xu return 0; 36589cee8b1SHerbert Xu } 36689cee8b1SHerbert Xu 3671da177e4SLinus Torvalds /* Add new segment to existing queue. */ 3681706d587SHerbert Xu static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) 3691da177e4SLinus Torvalds { 3701da177e4SLinus Torvalds struct sk_buff *prev, *next; 3711706d587SHerbert Xu struct net_device *dev; 3721da177e4SLinus Torvalds int flags, offset; 3731da177e4SLinus Torvalds int ihl, end; 3741706d587SHerbert Xu int err = -ENOENT; 3756623e3b2SEric Dumazet u8 ecn; 3761da177e4SLinus Torvalds 377bc578a54SJoe Perches if (qp->q.last_in & INET_FRAG_COMPLETE) 3781da177e4SLinus Torvalds goto err; 3791da177e4SLinus Torvalds 38089cee8b1SHerbert Xu if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && 3811706d587SHerbert Xu unlikely(ip_frag_too_far(qp)) && 3821706d587SHerbert Xu unlikely(err = ip_frag_reinit(qp))) { 38389cee8b1SHerbert Xu ipq_kill(qp); 38489cee8b1SHerbert Xu goto err; 38589cee8b1SHerbert Xu } 38689cee8b1SHerbert Xu 3876623e3b2SEric Dumazet ecn = ip4_frag_ecn(ip_hdr(skb)->tos); 388eddc9ec5SArnaldo Carvalho de Melo offset = ntohs(ip_hdr(skb)->frag_off); 3891da177e4SLinus Torvalds flags = offset & ~IP_OFFSET; 3901da177e4SLinus Torvalds offset &= IP_OFFSET; 3911da177e4SLinus Torvalds offset <<= 3; /* offset is in 8-byte chunks */ 392c9bdd4b5SArnaldo Carvalho de Melo ihl = ip_hdrlen(skb); 3931da177e4SLinus Torvalds 3941da177e4SLinus Torvalds /* Determine the position of this fragment. */ 3951da177e4SLinus Torvalds end = offset + skb->len - ihl; 3961706d587SHerbert Xu err = -EINVAL; 3971da177e4SLinus Torvalds 3981da177e4SLinus Torvalds /* Is this the final fragment? */ 3991da177e4SLinus Torvalds if ((flags & IP_MF) == 0) { 4001da177e4SLinus Torvalds /* If we already have some bits beyond end 40142b2aa86SJustin P. Mattock * or have different end, the segment is corrupted. 4021da177e4SLinus Torvalds */ 4035ab11c98SPavel Emelyanov if (end < qp->q.len || 404bc578a54SJoe Perches ((qp->q.last_in & INET_FRAG_LAST_IN) && end != qp->q.len)) 4051da177e4SLinus Torvalds goto err; 406bc578a54SJoe Perches qp->q.last_in |= INET_FRAG_LAST_IN; 4075ab11c98SPavel Emelyanov qp->q.len = end; 4081da177e4SLinus Torvalds } else { 4091da177e4SLinus Torvalds if (end&7) { 4101da177e4SLinus Torvalds end &= ~7; 4111da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 4121da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 4131da177e4SLinus Torvalds } 4145ab11c98SPavel Emelyanov if (end > qp->q.len) { 4151da177e4SLinus Torvalds /* Some bits beyond end -> corruption. */ 416bc578a54SJoe Perches if (qp->q.last_in & INET_FRAG_LAST_IN) 4171da177e4SLinus Torvalds goto err; 4185ab11c98SPavel Emelyanov qp->q.len = end; 4191da177e4SLinus Torvalds } 4201da177e4SLinus Torvalds } 4211da177e4SLinus Torvalds if (end == offset) 4221da177e4SLinus Torvalds goto err; 4231da177e4SLinus Torvalds 4241706d587SHerbert Xu err = -ENOMEM; 4251da177e4SLinus Torvalds if (pskb_pull(skb, ihl) == NULL) 4261da177e4SLinus Torvalds goto err; 4271706d587SHerbert Xu 4281706d587SHerbert Xu err = pskb_trim_rcsum(skb, end - offset); 4291706d587SHerbert Xu if (err) 4301da177e4SLinus Torvalds goto err; 4311da177e4SLinus Torvalds 4321da177e4SLinus Torvalds /* Find out which fragments are in front and at the back of us 4331da177e4SLinus Torvalds * in the chain of fragments so far. We must know where to put 4341da177e4SLinus Torvalds * this fragment, right? 4351da177e4SLinus Torvalds */ 436d6bebca9SChangli Gao prev = qp->q.fragments_tail; 437d6bebca9SChangli Gao if (!prev || FRAG_CB(prev)->offset < offset) { 438d6bebca9SChangli Gao next = NULL; 439d6bebca9SChangli Gao goto found; 440d6bebca9SChangli Gao } 4411da177e4SLinus Torvalds prev = NULL; 4425ab11c98SPavel Emelyanov for (next = qp->q.fragments; next != NULL; next = next->next) { 4431da177e4SLinus Torvalds if (FRAG_CB(next)->offset >= offset) 4441da177e4SLinus Torvalds break; /* bingo! */ 4451da177e4SLinus Torvalds prev = next; 4461da177e4SLinus Torvalds } 4471da177e4SLinus Torvalds 448d6bebca9SChangli Gao found: 4491da177e4SLinus Torvalds /* We found where to put this one. Check for overlap with 4501da177e4SLinus Torvalds * preceding fragment, and, if needed, align things so that 4511da177e4SLinus Torvalds * any overlaps are eliminated. 4521da177e4SLinus Torvalds */ 4531da177e4SLinus Torvalds if (prev) { 4541da177e4SLinus Torvalds int i = (FRAG_CB(prev)->offset + prev->len) - offset; 4551da177e4SLinus Torvalds 4561da177e4SLinus Torvalds if (i > 0) { 4571da177e4SLinus Torvalds offset += i; 4581706d587SHerbert Xu err = -EINVAL; 4591da177e4SLinus Torvalds if (end <= offset) 4601da177e4SLinus Torvalds goto err; 4611706d587SHerbert Xu err = -ENOMEM; 4621da177e4SLinus Torvalds if (!pskb_pull(skb, i)) 4631da177e4SLinus Torvalds goto err; 4641da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 4651da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 4661da177e4SLinus Torvalds } 4671da177e4SLinus Torvalds } 4681da177e4SLinus Torvalds 4691706d587SHerbert Xu err = -ENOMEM; 4701706d587SHerbert Xu 4711da177e4SLinus Torvalds while (next && FRAG_CB(next)->offset < end) { 4721da177e4SLinus Torvalds int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */ 4731da177e4SLinus Torvalds 4741da177e4SLinus Torvalds if (i < next->len) { 4751da177e4SLinus Torvalds /* Eat head of the next overlapped fragment 4761da177e4SLinus Torvalds * and leave the loop. The next ones cannot overlap. 4771da177e4SLinus Torvalds */ 4781da177e4SLinus Torvalds if (!pskb_pull(next, i)) 4791da177e4SLinus Torvalds goto err; 4801da177e4SLinus Torvalds FRAG_CB(next)->offset += i; 4815ab11c98SPavel Emelyanov qp->q.meat -= i; 4821da177e4SLinus Torvalds if (next->ip_summed != CHECKSUM_UNNECESSARY) 4831da177e4SLinus Torvalds next->ip_summed = CHECKSUM_NONE; 4841da177e4SLinus Torvalds break; 4851da177e4SLinus Torvalds } else { 4861da177e4SLinus Torvalds struct sk_buff *free_it = next; 4871da177e4SLinus Torvalds 48847c6bf77SPeter Zijlstra /* Old fragment is completely overridden with 4891da177e4SLinus Torvalds * new one drop it. 4901da177e4SLinus Torvalds */ 4911da177e4SLinus Torvalds next = next->next; 4921da177e4SLinus Torvalds 4931da177e4SLinus Torvalds if (prev) 4941da177e4SLinus Torvalds prev->next = next; 4951da177e4SLinus Torvalds else 4965ab11c98SPavel Emelyanov qp->q.fragments = next; 4971da177e4SLinus Torvalds 4985ab11c98SPavel Emelyanov qp->q.meat -= free_it->len; 499a95d8c88SEric Dumazet frag_kfree_skb(qp->q.net, free_it); 5001da177e4SLinus Torvalds } 5011da177e4SLinus Torvalds } 5021da177e4SLinus Torvalds 5031da177e4SLinus Torvalds FRAG_CB(skb)->offset = offset; 5041da177e4SLinus Torvalds 5051da177e4SLinus Torvalds /* Insert this fragment in the chain of fragments. */ 5061da177e4SLinus Torvalds skb->next = next; 507d6bebca9SChangli Gao if (!next) 508d6bebca9SChangli Gao qp->q.fragments_tail = skb; 5091da177e4SLinus Torvalds if (prev) 5101da177e4SLinus Torvalds prev->next = skb; 5111da177e4SLinus Torvalds else 5125ab11c98SPavel Emelyanov qp->q.fragments = skb; 5131da177e4SLinus Torvalds 5141706d587SHerbert Xu dev = skb->dev; 5151706d587SHerbert Xu if (dev) { 5161706d587SHerbert Xu qp->iif = dev->ifindex; 5171da177e4SLinus Torvalds skb->dev = NULL; 5181706d587SHerbert Xu } 5195ab11c98SPavel Emelyanov qp->q.stamp = skb->tstamp; 5205ab11c98SPavel Emelyanov qp->q.meat += skb->len; 5216623e3b2SEric Dumazet qp->ecn |= ecn; 5226ddc0822SPavel Emelyanov atomic_add(skb->truesize, &qp->q.net->mem); 5231da177e4SLinus Torvalds if (offset == 0) 524bc578a54SJoe Perches qp->q.last_in |= INET_FRAG_FIRST_IN; 5251da177e4SLinus Torvalds 5265f2d04f1SPatrick McHardy if (ip_hdr(skb)->frag_off & htons(IP_DF) && 5275f2d04f1SPatrick McHardy skb->len + ihl > qp->q.max_size) 5285f2d04f1SPatrick McHardy qp->q.max_size = skb->len + ihl; 5295f2d04f1SPatrick McHardy 530bc578a54SJoe Perches if (qp->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && 531bc578a54SJoe Perches qp->q.meat == qp->q.len) 5321706d587SHerbert Xu return ip_frag_reasm(qp, prev, dev); 5331706d587SHerbert Xu 5347eb95156SPavel Emelyanov write_lock(&ip4_frags.lock); 5353140c25cSPavel Emelyanov list_move_tail(&qp->q.lru_list, &qp->q.net->lru_list); 5367eb95156SPavel Emelyanov write_unlock(&ip4_frags.lock); 5371706d587SHerbert Xu return -EINPROGRESS; 5381da177e4SLinus Torvalds 5391da177e4SLinus Torvalds err: 5401da177e4SLinus Torvalds kfree_skb(skb); 5411706d587SHerbert Xu return err; 5421da177e4SLinus Torvalds } 5431da177e4SLinus Torvalds 5441da177e4SLinus Torvalds 5451da177e4SLinus Torvalds /* Build a new IP datagram from all its fragments. */ 5461da177e4SLinus Torvalds 5471706d587SHerbert Xu static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 5481706d587SHerbert Xu struct net_device *dev) 5491da177e4SLinus Torvalds { 5502bad35b7SJorge Boncompte [DTI2] struct net *net = container_of(qp->q.net, struct net, ipv4.frags); 5511da177e4SLinus Torvalds struct iphdr *iph; 5525ab11c98SPavel Emelyanov struct sk_buff *fp, *head = qp->q.fragments; 5531da177e4SLinus Torvalds int len; 5541da177e4SLinus Torvalds int ihlen; 5551706d587SHerbert Xu int err; 5563cc49492SEric Dumazet int sum_truesize; 5575173cc05SEric Dumazet u8 ecn; 5581da177e4SLinus Torvalds 5591da177e4SLinus Torvalds ipq_kill(qp); 5601da177e4SLinus Torvalds 5615173cc05SEric Dumazet ecn = ip4_frag_ecn_table[qp->ecn]; 5625173cc05SEric Dumazet if (unlikely(ecn == 0xff)) { 5635173cc05SEric Dumazet err = -EINVAL; 5645173cc05SEric Dumazet goto out_fail; 5655173cc05SEric Dumazet } 5661706d587SHerbert Xu /* Make the one we just received the head. */ 5671706d587SHerbert Xu if (prev) { 5681706d587SHerbert Xu head = prev->next; 5691706d587SHerbert Xu fp = skb_clone(head, GFP_ATOMIC); 5701706d587SHerbert Xu if (!fp) 5711706d587SHerbert Xu goto out_nomem; 5721706d587SHerbert Xu 5731706d587SHerbert Xu fp->next = head->next; 574d6bebca9SChangli Gao if (!fp->next) 575d6bebca9SChangli Gao qp->q.fragments_tail = fp; 5761706d587SHerbert Xu prev->next = fp; 5771706d587SHerbert Xu 5785ab11c98SPavel Emelyanov skb_morph(head, qp->q.fragments); 5795ab11c98SPavel Emelyanov head->next = qp->q.fragments->next; 5801706d587SHerbert Xu 581cbf8f7bbSEric Dumazet consume_skb(qp->q.fragments); 5825ab11c98SPavel Emelyanov qp->q.fragments = head; 5831706d587SHerbert Xu } 5841706d587SHerbert Xu 585547b792cSIlpo Järvinen WARN_ON(head == NULL); 586547b792cSIlpo Järvinen WARN_ON(FRAG_CB(head)->offset != 0); 5871da177e4SLinus Torvalds 5881da177e4SLinus Torvalds /* Allocate a new buffer for the datagram. */ 589c9bdd4b5SArnaldo Carvalho de Melo ihlen = ip_hdrlen(head); 5905ab11c98SPavel Emelyanov len = ihlen + qp->q.len; 5911da177e4SLinus Torvalds 5921706d587SHerbert Xu err = -E2BIG; 5931da177e4SLinus Torvalds if (len > 65535) 5941da177e4SLinus Torvalds goto out_oversize; 5951da177e4SLinus Torvalds 5961da177e4SLinus Torvalds /* Head of list must not be cloned. */ 5971da177e4SLinus Torvalds if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) 5981da177e4SLinus Torvalds goto out_nomem; 5991da177e4SLinus Torvalds 6001da177e4SLinus Torvalds /* If the first fragment is fragmented itself, we split 6011da177e4SLinus Torvalds * it to two chunks: the first with data and paged part 6021da177e4SLinus Torvalds * and the second, holding only fragments. */ 60321dc3301SDavid S. Miller if (skb_has_frag_list(head)) { 6041da177e4SLinus Torvalds struct sk_buff *clone; 6051da177e4SLinus Torvalds int i, plen = 0; 6061da177e4SLinus Torvalds 6071da177e4SLinus Torvalds if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) 6081da177e4SLinus Torvalds goto out_nomem; 6091da177e4SLinus Torvalds clone->next = head->next; 6101da177e4SLinus Torvalds head->next = clone; 6111da177e4SLinus Torvalds skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 612d7fcf1a5SDavid S. Miller skb_frag_list_init(head); 6131da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(head)->nr_frags; i++) 6149e903e08SEric Dumazet plen += skb_frag_size(&skb_shinfo(head)->frags[i]); 6151da177e4SLinus Torvalds clone->len = clone->data_len = head->data_len - plen; 6161da177e4SLinus Torvalds head->data_len -= clone->len; 6171da177e4SLinus Torvalds head->len -= clone->len; 6181da177e4SLinus Torvalds clone->csum = 0; 6191da177e4SLinus Torvalds clone->ip_summed = head->ip_summed; 6206ddc0822SPavel Emelyanov atomic_add(clone->truesize, &qp->q.net->mem); 6211da177e4SLinus Torvalds } 6221da177e4SLinus Torvalds 623d56f90a7SArnaldo Carvalho de Melo skb_push(head, head->data - skb_network_header(head)); 6241da177e4SLinus Torvalds 6253cc49492SEric Dumazet sum_truesize = head->truesize; 6263cc49492SEric Dumazet for (fp = head->next; fp;) { 6273cc49492SEric Dumazet bool headstolen; 6283cc49492SEric Dumazet int delta; 6293cc49492SEric Dumazet struct sk_buff *next = fp->next; 6303cc49492SEric Dumazet 6313cc49492SEric Dumazet sum_truesize += fp->truesize; 6321da177e4SLinus Torvalds if (head->ip_summed != fp->ip_summed) 6331da177e4SLinus Torvalds head->ip_summed = CHECKSUM_NONE; 63484fa7933SPatrick McHardy else if (head->ip_summed == CHECKSUM_COMPLETE) 6351da177e4SLinus Torvalds head->csum = csum_add(head->csum, fp->csum); 6363cc49492SEric Dumazet 6373cc49492SEric Dumazet if (skb_try_coalesce(head, fp, &headstolen, &delta)) { 6383cc49492SEric Dumazet kfree_skb_partial(fp, headstolen); 6393cc49492SEric Dumazet } else { 6403cc49492SEric Dumazet if (!skb_shinfo(head)->frag_list) 6413cc49492SEric Dumazet skb_shinfo(head)->frag_list = fp; 6423cc49492SEric Dumazet head->data_len += fp->len; 6433cc49492SEric Dumazet head->len += fp->len; 6441da177e4SLinus Torvalds head->truesize += fp->truesize; 6451da177e4SLinus Torvalds } 6463cc49492SEric Dumazet fp = next; 6473cc49492SEric Dumazet } 6483cc49492SEric Dumazet atomic_sub(sum_truesize, &qp->q.net->mem); 6491da177e4SLinus Torvalds 6501da177e4SLinus Torvalds head->next = NULL; 6511da177e4SLinus Torvalds head->dev = dev; 6525ab11c98SPavel Emelyanov head->tstamp = qp->q.stamp; 6535f2d04f1SPatrick McHardy IPCB(head)->frag_max_size = qp->q.max_size; 6541da177e4SLinus Torvalds 655eddc9ec5SArnaldo Carvalho de Melo iph = ip_hdr(head); 6565f2d04f1SPatrick McHardy /* max_size != 0 implies at least one fragment had IP_DF set */ 6575f2d04f1SPatrick McHardy iph->frag_off = qp->q.max_size ? htons(IP_DF) : 0; 6581da177e4SLinus Torvalds iph->tot_len = htons(len); 6595173cc05SEric Dumazet iph->tos |= ecn; 6602bad35b7SJorge Boncompte [DTI2] IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS); 6615ab11c98SPavel Emelyanov qp->q.fragments = NULL; 662d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 6631706d587SHerbert Xu return 0; 6641da177e4SLinus Torvalds 6651da177e4SLinus Torvalds out_nomem: 666afd46503SJoe Perches LIMIT_NETDEBUG(KERN_ERR pr_fmt("queue_glue: no memory for gluing queue %p\n"), 667afd46503SJoe Perches qp); 66845542479SDavid Howells err = -ENOMEM; 6691da177e4SLinus Torvalds goto out_fail; 6701da177e4SLinus Torvalds out_oversize: 671e87cc472SJoe Perches net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->saddr); 6721da177e4SLinus Torvalds out_fail: 673bbf31bf1SDavid Ford IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 6741706d587SHerbert Xu return err; 6751da177e4SLinus Torvalds } 6761da177e4SLinus Torvalds 6771da177e4SLinus Torvalds /* Process an incoming IP datagram fragment. */ 678776c729eSHerbert Xu int ip_defrag(struct sk_buff *skb, u32 user) 6791da177e4SLinus Torvalds { 6801da177e4SLinus Torvalds struct ipq *qp; 681ac18e750SPavel Emelyanov struct net *net; 6821da177e4SLinus Torvalds 683adf30907SEric Dumazet net = skb->dev ? dev_net(skb->dev) : dev_net(skb_dst(skb)->dev); 6847c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMREQDS); 6851da177e4SLinus Torvalds 6861da177e4SLinus Torvalds /* Start by cleaning up the memory. */ 6876ddc0822SPavel Emelyanov ip_evictor(net); 6881da177e4SLinus Torvalds 6891da177e4SLinus Torvalds /* Lookup (or create) queue header */ 690ac18e750SPavel Emelyanov if ((qp = ip_find(net, ip_hdr(skb), user)) != NULL) { 6911706d587SHerbert Xu int ret; 6921da177e4SLinus Torvalds 6935ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 6941da177e4SLinus Torvalds 6951706d587SHerbert Xu ret = ip_frag_queue(qp, skb); 6961da177e4SLinus Torvalds 6975ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 6984b6cb5d8SPavel Emelyanov ipq_put(qp); 699776c729eSHerbert Xu return ret; 7001da177e4SLinus Torvalds } 7011da177e4SLinus Torvalds 7027c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 7031da177e4SLinus Torvalds kfree_skb(skb); 704776c729eSHerbert Xu return -ENOMEM; 7051da177e4SLinus Torvalds } 7064bc2f18bSEric Dumazet EXPORT_SYMBOL(ip_defrag); 7071da177e4SLinus Torvalds 708bc416d97SEric Dumazet struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) 709bc416d97SEric Dumazet { 710bc416d97SEric Dumazet const struct iphdr *iph; 711bc416d97SEric Dumazet u32 len; 712bc416d97SEric Dumazet 713bc416d97SEric Dumazet if (skb->protocol != htons(ETH_P_IP)) 714bc416d97SEric Dumazet return skb; 715bc416d97SEric Dumazet 716bc416d97SEric Dumazet if (!pskb_may_pull(skb, sizeof(struct iphdr))) 717bc416d97SEric Dumazet return skb; 718bc416d97SEric Dumazet 719bc416d97SEric Dumazet iph = ip_hdr(skb); 720bc416d97SEric Dumazet if (iph->ihl < 5 || iph->version != 4) 721bc416d97SEric Dumazet return skb; 722bc416d97SEric Dumazet if (!pskb_may_pull(skb, iph->ihl*4)) 723bc416d97SEric Dumazet return skb; 724bc416d97SEric Dumazet iph = ip_hdr(skb); 725bc416d97SEric Dumazet len = ntohs(iph->tot_len); 726bc416d97SEric Dumazet if (skb->len < len || len < (iph->ihl * 4)) 727bc416d97SEric Dumazet return skb; 728bc416d97SEric Dumazet 729bc416d97SEric Dumazet if (ip_is_fragment(ip_hdr(skb))) { 730bc416d97SEric Dumazet skb = skb_share_check(skb, GFP_ATOMIC); 731bc416d97SEric Dumazet if (skb) { 732bc416d97SEric Dumazet if (pskb_trim_rcsum(skb, len)) 733bc416d97SEric Dumazet return skb; 734bc416d97SEric Dumazet memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 735bc416d97SEric Dumazet if (ip_defrag(skb, user)) 736bc416d97SEric Dumazet return NULL; 737bc416d97SEric Dumazet skb->rxhash = 0; 738bc416d97SEric Dumazet } 739bc416d97SEric Dumazet } 740bc416d97SEric Dumazet return skb; 741bc416d97SEric Dumazet } 742bc416d97SEric Dumazet EXPORT_SYMBOL(ip_check_defrag); 743bc416d97SEric Dumazet 7448d8354d2SPavel Emelyanov #ifdef CONFIG_SYSCTL 7458d8354d2SPavel Emelyanov static int zero; 7468d8354d2SPavel Emelyanov 7470a64b4b8SPavel Emelyanov static struct ctl_table ip4_frags_ns_ctl_table[] = { 7488d8354d2SPavel Emelyanov { 7498d8354d2SPavel Emelyanov .procname = "ipfrag_high_thresh", 750e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.high_thresh, 7518d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7528d8354d2SPavel Emelyanov .mode = 0644, 7536d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec 7548d8354d2SPavel Emelyanov }, 7558d8354d2SPavel Emelyanov { 7568d8354d2SPavel Emelyanov .procname = "ipfrag_low_thresh", 757e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.low_thresh, 7588d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7598d8354d2SPavel Emelyanov .mode = 0644, 7606d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec 7618d8354d2SPavel Emelyanov }, 7628d8354d2SPavel Emelyanov { 7638d8354d2SPavel Emelyanov .procname = "ipfrag_time", 764b2fd5321SPavel Emelyanov .data = &init_net.ipv4.frags.timeout, 7658d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7668d8354d2SPavel Emelyanov .mode = 0644, 7676d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7688d8354d2SPavel Emelyanov }, 7697d291ebbSPavel Emelyanov { } 7707d291ebbSPavel Emelyanov }; 7717d291ebbSPavel Emelyanov 7727d291ebbSPavel Emelyanov static struct ctl_table ip4_frags_ctl_table[] = { 7738d8354d2SPavel Emelyanov { 7748d8354d2SPavel Emelyanov .procname = "ipfrag_secret_interval", 7753b4bc4a2SPavel Emelyanov .data = &ip4_frags.secret_interval, 7768d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7778d8354d2SPavel Emelyanov .mode = 0644, 7786d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7798d8354d2SPavel Emelyanov }, 7808d8354d2SPavel Emelyanov { 7818d8354d2SPavel Emelyanov .procname = "ipfrag_max_dist", 7828d8354d2SPavel Emelyanov .data = &sysctl_ipfrag_max_dist, 7838d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7848d8354d2SPavel Emelyanov .mode = 0644, 7856d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_minmax, 7868d8354d2SPavel Emelyanov .extra1 = &zero 7878d8354d2SPavel Emelyanov }, 7888d8354d2SPavel Emelyanov { } 7898d8354d2SPavel Emelyanov }; 7908d8354d2SPavel Emelyanov 7912c8c1e72SAlexey Dobriyan static int __net_init ip4_frags_ns_ctl_register(struct net *net) 7928d8354d2SPavel Emelyanov { 793e4a2d5c2SPavel Emelyanov struct ctl_table *table; 7948d8354d2SPavel Emelyanov struct ctl_table_header *hdr; 7958d8354d2SPavel Emelyanov 7960a64b4b8SPavel Emelyanov table = ip4_frags_ns_ctl_table; 79709ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) { 7980a64b4b8SPavel Emelyanov table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL); 799e4a2d5c2SPavel Emelyanov if (table == NULL) 800e4a2d5c2SPavel Emelyanov goto err_alloc; 801e4a2d5c2SPavel Emelyanov 802e31e0bdcSPavel Emelyanov table[0].data = &net->ipv4.frags.high_thresh; 803e31e0bdcSPavel Emelyanov table[1].data = &net->ipv4.frags.low_thresh; 804b2fd5321SPavel Emelyanov table[2].data = &net->ipv4.frags.timeout; 805464dc801SEric W. Biederman 806464dc801SEric W. Biederman /* Don't export sysctls to unprivileged users */ 807464dc801SEric W. Biederman if (net->user_ns != &init_user_ns) 808464dc801SEric W. Biederman table[0].procname = NULL; 809e4a2d5c2SPavel Emelyanov } 810e4a2d5c2SPavel Emelyanov 811ec8f23ceSEric W. Biederman hdr = register_net_sysctl(net, "net/ipv4", table); 812e4a2d5c2SPavel Emelyanov if (hdr == NULL) 813e4a2d5c2SPavel Emelyanov goto err_reg; 814e4a2d5c2SPavel Emelyanov 815e4a2d5c2SPavel Emelyanov net->ipv4.frags_hdr = hdr; 816e4a2d5c2SPavel Emelyanov return 0; 817e4a2d5c2SPavel Emelyanov 818e4a2d5c2SPavel Emelyanov err_reg: 81909ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) 820e4a2d5c2SPavel Emelyanov kfree(table); 821e4a2d5c2SPavel Emelyanov err_alloc: 822e4a2d5c2SPavel Emelyanov return -ENOMEM; 823e4a2d5c2SPavel Emelyanov } 824e4a2d5c2SPavel Emelyanov 8252c8c1e72SAlexey Dobriyan static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net) 826e4a2d5c2SPavel Emelyanov { 827e4a2d5c2SPavel Emelyanov struct ctl_table *table; 828e4a2d5c2SPavel Emelyanov 829e4a2d5c2SPavel Emelyanov table = net->ipv4.frags_hdr->ctl_table_arg; 830e4a2d5c2SPavel Emelyanov unregister_net_sysctl_table(net->ipv4.frags_hdr); 831e4a2d5c2SPavel Emelyanov kfree(table); 8328d8354d2SPavel Emelyanov } 8337d291ebbSPavel Emelyanov 8347d291ebbSPavel Emelyanov static void ip4_frags_ctl_register(void) 8357d291ebbSPavel Emelyanov { 83643444757SEric W. Biederman register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table); 8377d291ebbSPavel Emelyanov } 8388d8354d2SPavel Emelyanov #else 8390a64b4b8SPavel Emelyanov static inline int ip4_frags_ns_ctl_register(struct net *net) 8408d8354d2SPavel Emelyanov { 8418d8354d2SPavel Emelyanov return 0; 8428d8354d2SPavel Emelyanov } 843e4a2d5c2SPavel Emelyanov 8440a64b4b8SPavel Emelyanov static inline void ip4_frags_ns_ctl_unregister(struct net *net) 845e4a2d5c2SPavel Emelyanov { 846e4a2d5c2SPavel Emelyanov } 8477d291ebbSPavel Emelyanov 8487d291ebbSPavel Emelyanov static inline void ip4_frags_ctl_register(void) 8497d291ebbSPavel Emelyanov { 8507d291ebbSPavel Emelyanov } 8518d8354d2SPavel Emelyanov #endif 8528d8354d2SPavel Emelyanov 8532c8c1e72SAlexey Dobriyan static int __net_init ipv4_frags_init_net(struct net *net) 8548d8354d2SPavel Emelyanov { 855b2fd5321SPavel Emelyanov /* 856e31e0bdcSPavel Emelyanov * Fragment cache limits. We will commit 256K at one time. Should we 857e31e0bdcSPavel Emelyanov * cross that limit we will prune down to 192K. This should cope with 858e31e0bdcSPavel Emelyanov * even the most extreme cases without allowing an attacker to 859e31e0bdcSPavel Emelyanov * measurably harm machine performance. 860e31e0bdcSPavel Emelyanov */ 861e31e0bdcSPavel Emelyanov net->ipv4.frags.high_thresh = 256 * 1024; 862e31e0bdcSPavel Emelyanov net->ipv4.frags.low_thresh = 192 * 1024; 863e31e0bdcSPavel Emelyanov /* 864b2fd5321SPavel Emelyanov * Important NOTE! Fragment queue must be destroyed before MSL expires. 865b2fd5321SPavel Emelyanov * RFC791 is wrong proposing to prolongate timer each fragment arrival 866b2fd5321SPavel Emelyanov * by TTL. 867b2fd5321SPavel Emelyanov */ 868b2fd5321SPavel Emelyanov net->ipv4.frags.timeout = IP_FRAG_TIME; 869b2fd5321SPavel Emelyanov 870e5a2bb84SPavel Emelyanov inet_frags_init_net(&net->ipv4.frags); 871e5a2bb84SPavel Emelyanov 8720a64b4b8SPavel Emelyanov return ip4_frags_ns_ctl_register(net); 8738d8354d2SPavel Emelyanov } 8748d8354d2SPavel Emelyanov 8752c8c1e72SAlexey Dobriyan static void __net_exit ipv4_frags_exit_net(struct net *net) 87681566e83SPavel Emelyanov { 8770a64b4b8SPavel Emelyanov ip4_frags_ns_ctl_unregister(net); 87881566e83SPavel Emelyanov inet_frags_exit_net(&net->ipv4.frags, &ip4_frags); 87981566e83SPavel Emelyanov } 88081566e83SPavel Emelyanov 88181566e83SPavel Emelyanov static struct pernet_operations ip4_frags_ops = { 88281566e83SPavel Emelyanov .init = ipv4_frags_init_net, 88381566e83SPavel Emelyanov .exit = ipv4_frags_exit_net, 88481566e83SPavel Emelyanov }; 88581566e83SPavel Emelyanov 886b7aa0bf7SEric Dumazet void __init ipfrag_init(void) 8871da177e4SLinus Torvalds { 8887d291ebbSPavel Emelyanov ip4_frags_ctl_register(); 88981566e83SPavel Emelyanov register_pernet_subsys(&ip4_frags_ops); 890321a3a99SPavel Emelyanov ip4_frags.hashfn = ip4_hashfn; 891c6fda282SPavel Emelyanov ip4_frags.constructor = ip4_frag_init; 8921e4b8287SPavel Emelyanov ip4_frags.destructor = ip4_frag_free; 8931e4b8287SPavel Emelyanov ip4_frags.skb_free = NULL; 8941e4b8287SPavel Emelyanov ip4_frags.qsize = sizeof(struct ipq); 895abd6523dSPavel Emelyanov ip4_frags.match = ip4_frag_match; 896e521db9dSPavel Emelyanov ip4_frags.frag_expire = ip_expire; 8973b4bc4a2SPavel Emelyanov ip4_frags.secret_interval = 10 * 60 * HZ; 8987eb95156SPavel Emelyanov inet_frags_init(&ip4_frags); 8991da177e4SLinus Torvalds } 900