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 826623e3b2SEric Dumazet static inline u8 ip4_frag_ecn(u8 tos) 836623e3b2SEric Dumazet { 845173cc05SEric Dumazet return 1 << (tos & INET_ECN_MASK); 856623e3b2SEric Dumazet } 866623e3b2SEric Dumazet 877eb95156SPavel Emelyanov static struct inet_frags ip4_frags; 881da177e4SLinus Torvalds 89e5a2bb84SPavel Emelyanov int ip_frag_nqueues(struct net *net) 907eb95156SPavel Emelyanov { 91e5a2bb84SPavel Emelyanov return net->ipv4.frags.nqueues; 927eb95156SPavel Emelyanov } 931da177e4SLinus Torvalds 946ddc0822SPavel Emelyanov int ip_frag_mem(struct net *net) 957eb95156SPavel Emelyanov { 96d433673eSJesper Dangaard Brouer return sum_frag_mem_limit(&net->ipv4.frags); 977eb95156SPavel Emelyanov } 981da177e4SLinus Torvalds 991706d587SHerbert Xu static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 1001706d587SHerbert Xu struct net_device *dev); 1011706d587SHerbert Xu 102c6fda282SPavel Emelyanov struct ip4_create_arg { 103c6fda282SPavel Emelyanov struct iphdr *iph; 104c6fda282SPavel Emelyanov u32 user; 105c6fda282SPavel Emelyanov }; 106c6fda282SPavel Emelyanov 10718277770SAl Viro static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot) 1081da177e4SLinus Torvalds { 109e7b519baSHannes Frederic Sowa net_get_random_once(&ip4_frags.rnd, sizeof(ip4_frags.rnd)); 11018277770SAl Viro return jhash_3words((__force u32)id << 16 | prot, 11118277770SAl Viro (__force u32)saddr, (__force u32)daddr, 112fb3cfe6eSFlorian Westphal ip4_frags.rnd); 1131da177e4SLinus Torvalds } 1141da177e4SLinus Torvalds 11536c77782SFlorian Westphal static unsigned int ip4_hashfn(const struct inet_frag_queue *q) 1161da177e4SLinus Torvalds { 11736c77782SFlorian Westphal const struct ipq *ipq; 1181da177e4SLinus Torvalds 119321a3a99SPavel Emelyanov ipq = container_of(q, struct ipq, q); 120321a3a99SPavel Emelyanov return ipqhashfn(ipq->id, ipq->saddr, ipq->daddr, ipq->protocol); 1211da177e4SLinus Torvalds } 1221da177e4SLinus Torvalds 12336c77782SFlorian Westphal static bool ip4_frag_match(const struct inet_frag_queue *q, const void *a) 124abd6523dSPavel Emelyanov { 12536c77782SFlorian Westphal const struct ipq *qp; 12636c77782SFlorian Westphal const struct ip4_create_arg *arg = a; 127abd6523dSPavel Emelyanov 128abd6523dSPavel Emelyanov qp = container_of(q, struct ipq, q); 129a02cec21SEric Dumazet return qp->id == arg->iph->id && 130abd6523dSPavel Emelyanov qp->saddr == arg->iph->saddr && 131abd6523dSPavel Emelyanov qp->daddr == arg->iph->daddr && 132abd6523dSPavel Emelyanov qp->protocol == arg->iph->protocol && 133a02cec21SEric Dumazet qp->user == arg->user; 134abd6523dSPavel Emelyanov } 135abd6523dSPavel Emelyanov 13636c77782SFlorian Westphal static void ip4_frag_init(struct inet_frag_queue *q, const void *a) 137c6fda282SPavel Emelyanov { 138c6fda282SPavel Emelyanov struct ipq *qp = container_of(q, struct ipq, q); 13954db0cc2SGao feng struct netns_ipv4 *ipv4 = container_of(q->net, struct netns_ipv4, 14054db0cc2SGao feng frags); 14154db0cc2SGao feng struct net *net = container_of(ipv4, struct net, ipv4); 14254db0cc2SGao feng 14336c77782SFlorian Westphal const struct ip4_create_arg *arg = a; 144c6fda282SPavel Emelyanov 145c6fda282SPavel Emelyanov qp->protocol = arg->iph->protocol; 146c6fda282SPavel Emelyanov qp->id = arg->iph->id; 1476623e3b2SEric Dumazet qp->ecn = ip4_frag_ecn(arg->iph->tos); 148c6fda282SPavel Emelyanov qp->saddr = arg->iph->saddr; 149c6fda282SPavel Emelyanov qp->daddr = arg->iph->daddr; 150c6fda282SPavel Emelyanov qp->user = arg->user; 151c6fda282SPavel Emelyanov qp->peer = sysctl_ipfrag_max_dist ? 152c0efc887SDavid S. Miller inet_getpeer_v4(net->ipv4.peers, arg->iph->saddr, 1) : NULL; 153c6fda282SPavel Emelyanov } 154c6fda282SPavel Emelyanov 1551e4b8287SPavel Emelyanov static __inline__ void ip4_frag_free(struct inet_frag_queue *q) 1561da177e4SLinus Torvalds { 1571e4b8287SPavel Emelyanov struct ipq *qp; 1581e4b8287SPavel Emelyanov 1591e4b8287SPavel Emelyanov qp = container_of(q, struct ipq, q); 1601e4b8287SPavel Emelyanov if (qp->peer) 1611e4b8287SPavel Emelyanov inet_putpeer(qp->peer); 1621da177e4SLinus Torvalds } 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds /* Destruction primitives. */ 1661da177e4SLinus Torvalds 1674b6cb5d8SPavel Emelyanov static __inline__ void ipq_put(struct ipq *ipq) 1681da177e4SLinus Torvalds { 169762cc408SPavel Emelyanov inet_frag_put(&ipq->q, &ip4_frags); 1701da177e4SLinus Torvalds } 1711da177e4SLinus Torvalds 1721da177e4SLinus Torvalds /* Kill ipq entry. It is not destroyed immediately, 1731da177e4SLinus Torvalds * because caller (and someone more) holds reference count. 1741da177e4SLinus Torvalds */ 1751da177e4SLinus Torvalds static void ipq_kill(struct ipq *ipq) 1761da177e4SLinus Torvalds { 177277e650dSPavel Emelyanov inet_frag_kill(&ipq->q, &ip4_frags); 1781da177e4SLinus Torvalds } 1791da177e4SLinus Torvalds 1801da177e4SLinus Torvalds /* Memory limiting on fragments. Evictor trashes the oldest 1811da177e4SLinus Torvalds * fragment queue until we are back under the threshold. 1821da177e4SLinus Torvalds */ 1836ddc0822SPavel Emelyanov static void ip_evictor(struct net *net) 1841da177e4SLinus Torvalds { 1858e7999c4SPavel Emelyanov int evicted; 1861da177e4SLinus Torvalds 1876b102865SAmerigo Wang evicted = inet_frag_evictor(&net->ipv4.frags, &ip4_frags, false); 1888e7999c4SPavel Emelyanov if (evicted) 189c5346fe3SPavel Emelyanov IP_ADD_STATS_BH(net, IPSTATS_MIB_REASMFAILS, evicted); 1901da177e4SLinus Torvalds } 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds /* 1931da177e4SLinus Torvalds * Oops, a fragment queue timed out. Kill it and send an ICMP reply. 1941da177e4SLinus Torvalds */ 1951da177e4SLinus Torvalds static void ip_expire(unsigned long arg) 1961da177e4SLinus Torvalds { 197e521db9dSPavel Emelyanov struct ipq *qp; 19884a3aa00SPavel Emelyanov struct net *net; 199e521db9dSPavel Emelyanov 200e521db9dSPavel Emelyanov qp = container_of((struct inet_frag_queue *) arg, struct ipq, q); 20184a3aa00SPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 2021da177e4SLinus Torvalds 2035ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 2041da177e4SLinus Torvalds 205bc578a54SJoe Perches if (qp->q.last_in & INET_FRAG_COMPLETE) 2061da177e4SLinus Torvalds goto out; 2071da177e4SLinus Torvalds 2081da177e4SLinus Torvalds ipq_kill(qp); 2091da177e4SLinus Torvalds 2107c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMTIMEOUT); 2117c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 2121da177e4SLinus Torvalds 213bc578a54SJoe Perches if ((qp->q.last_in & INET_FRAG_FIRST_IN) && qp->q.fragments != NULL) { 2145ab11c98SPavel Emelyanov struct sk_buff *head = qp->q.fragments; 21564f3b9e2SEric Dumazet const struct iphdr *iph; 21664f3b9e2SEric Dumazet int err; 217cb84663eSDenis V. Lunev 21869df9d59SEric Dumazet rcu_read_lock(); 21969df9d59SEric Dumazet head->dev = dev_get_by_index_rcu(net, qp->iif); 220e9017b55SShan Wei if (!head->dev) 221e9017b55SShan Wei goto out_rcu_unlock; 222e9017b55SShan Wei 22397599dc7SEric Dumazet /* skb has no dst, perform route lookup again */ 22464f3b9e2SEric Dumazet iph = ip_hdr(head); 225c6cffba4SDavid S. Miller err = ip_route_input_noref(head, iph->daddr, iph->saddr, 226c10237e0SDavid S. Miller iph->tos, head->dev); 22764f3b9e2SEric Dumazet if (err) 228e9017b55SShan Wei goto out_rcu_unlock; 229e9017b55SShan Wei 230e9017b55SShan Wei /* 231e9017b55SShan Wei * Only an end host needs to send an ICMP 232e9017b55SShan Wei * "Fragment Reassembly Timeout" message, per RFC792. 233e9017b55SShan Wei */ 234595fc71bSDavid S. Miller if (qp->user == IP_DEFRAG_AF_PACKET || 2357c3d5ab1SVasily Averin ((qp->user >= IP_DEFRAG_CONNTRACK_IN) && 2367c3d5ab1SVasily Averin (qp->user <= __IP_DEFRAG_CONNTRACK_IN_END) && 2377c3d5ab1SVasily Averin (skb_rtable(head)->rt_type != RTN_LOCAL))) 238e9017b55SShan Wei goto out_rcu_unlock; 239e9017b55SShan Wei 240e9017b55SShan Wei 241e9017b55SShan Wei /* Send an ICMP "Fragment Reassembly Timeout" message. */ 242e9017b55SShan Wei icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); 243e9017b55SShan Wei out_rcu_unlock: 244e9017b55SShan Wei rcu_read_unlock(); 245d1c9ae6dSPatrick McHardy } 2461da177e4SLinus Torvalds out: 2475ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 2484b6cb5d8SPavel Emelyanov ipq_put(qp); 2491da177e4SLinus Torvalds } 2501da177e4SLinus Torvalds 251abd6523dSPavel Emelyanov /* Find the correct entry in the "incomplete datagrams" queue for 252abd6523dSPavel Emelyanov * this IP datagram, and create new one, if nothing is found. 253abd6523dSPavel Emelyanov */ 254ac18e750SPavel Emelyanov static inline struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user) 2551da177e4SLinus Torvalds { 256c6fda282SPavel Emelyanov struct inet_frag_queue *q; 257c6fda282SPavel Emelyanov struct ip4_create_arg arg; 258abd6523dSPavel Emelyanov unsigned int hash; 2591da177e4SLinus Torvalds 260c6fda282SPavel Emelyanov arg.iph = iph; 261c6fda282SPavel Emelyanov arg.user = user; 2629a375803SPavel Emelyanov 2639a375803SPavel Emelyanov read_lock(&ip4_frags.lock); 264abd6523dSPavel Emelyanov hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol); 265c6fda282SPavel Emelyanov 266ac18e750SPavel Emelyanov q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash); 2675a3da1feSHannes Frederic Sowa if (IS_ERR_OR_NULL(q)) { 2685a3da1feSHannes Frederic Sowa inet_frag_maybe_warn_overflow(q, pr_fmt()); 2691da177e4SLinus Torvalds return NULL; 2701da177e4SLinus Torvalds } 2715a3da1feSHannes Frederic Sowa return container_of(q, struct ipq, q); 2725a3da1feSHannes Frederic Sowa } 2731da177e4SLinus Torvalds 27489cee8b1SHerbert Xu /* Is the fragment too far ahead to be part of ipq? */ 27589cee8b1SHerbert Xu static inline int ip_frag_too_far(struct ipq *qp) 27689cee8b1SHerbert Xu { 27789cee8b1SHerbert Xu struct inet_peer *peer = qp->peer; 27889cee8b1SHerbert Xu unsigned int max = sysctl_ipfrag_max_dist; 27989cee8b1SHerbert Xu unsigned int start, end; 28089cee8b1SHerbert Xu 28189cee8b1SHerbert Xu int rc; 28289cee8b1SHerbert Xu 28389cee8b1SHerbert Xu if (!peer || !max) 28489cee8b1SHerbert Xu return 0; 28589cee8b1SHerbert Xu 28689cee8b1SHerbert Xu start = qp->rid; 28789cee8b1SHerbert Xu end = atomic_inc_return(&peer->rid); 28889cee8b1SHerbert Xu qp->rid = end; 28989cee8b1SHerbert Xu 2905ab11c98SPavel Emelyanov rc = qp->q.fragments && (end - start) > max; 29189cee8b1SHerbert Xu 29289cee8b1SHerbert Xu if (rc) { 2937c73a6faSPavel Emelyanov struct net *net; 2947c73a6faSPavel Emelyanov 2957c73a6faSPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 2967c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 29789cee8b1SHerbert Xu } 29889cee8b1SHerbert Xu 29989cee8b1SHerbert Xu return rc; 30089cee8b1SHerbert Xu } 30189cee8b1SHerbert Xu 30289cee8b1SHerbert Xu static int ip_frag_reinit(struct ipq *qp) 30389cee8b1SHerbert Xu { 30489cee8b1SHerbert Xu struct sk_buff *fp; 305d433673eSJesper Dangaard Brouer unsigned int sum_truesize = 0; 30689cee8b1SHerbert Xu 307b2fd5321SPavel Emelyanov if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) { 3085ab11c98SPavel Emelyanov atomic_inc(&qp->q.refcnt); 30989cee8b1SHerbert Xu return -ETIMEDOUT; 31089cee8b1SHerbert Xu } 31189cee8b1SHerbert Xu 3125ab11c98SPavel Emelyanov fp = qp->q.fragments; 31389cee8b1SHerbert Xu do { 31489cee8b1SHerbert Xu struct sk_buff *xp = fp->next; 315d433673eSJesper Dangaard Brouer 316d433673eSJesper Dangaard Brouer sum_truesize += fp->truesize; 317d433673eSJesper Dangaard Brouer kfree_skb(fp); 31889cee8b1SHerbert Xu fp = xp; 31989cee8b1SHerbert Xu } while (fp); 320d433673eSJesper Dangaard Brouer sub_frag_mem_limit(&qp->q, sum_truesize); 32189cee8b1SHerbert Xu 3225ab11c98SPavel Emelyanov qp->q.last_in = 0; 3235ab11c98SPavel Emelyanov qp->q.len = 0; 3245ab11c98SPavel Emelyanov qp->q.meat = 0; 3255ab11c98SPavel Emelyanov qp->q.fragments = NULL; 326d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 32789cee8b1SHerbert Xu qp->iif = 0; 3286623e3b2SEric Dumazet qp->ecn = 0; 32989cee8b1SHerbert Xu 33089cee8b1SHerbert Xu return 0; 33189cee8b1SHerbert Xu } 33289cee8b1SHerbert Xu 3331da177e4SLinus Torvalds /* Add new segment to existing queue. */ 3341706d587SHerbert Xu static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) 3351da177e4SLinus Torvalds { 3361da177e4SLinus Torvalds struct sk_buff *prev, *next; 3371706d587SHerbert Xu struct net_device *dev; 3381da177e4SLinus Torvalds int flags, offset; 3391da177e4SLinus Torvalds int ihl, end; 3401706d587SHerbert Xu int err = -ENOENT; 3416623e3b2SEric Dumazet u8 ecn; 3421da177e4SLinus Torvalds 343bc578a54SJoe Perches if (qp->q.last_in & INET_FRAG_COMPLETE) 3441da177e4SLinus Torvalds goto err; 3451da177e4SLinus Torvalds 34689cee8b1SHerbert Xu if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && 3471706d587SHerbert Xu unlikely(ip_frag_too_far(qp)) && 3481706d587SHerbert Xu unlikely(err = ip_frag_reinit(qp))) { 34989cee8b1SHerbert Xu ipq_kill(qp); 35089cee8b1SHerbert Xu goto err; 35189cee8b1SHerbert Xu } 35289cee8b1SHerbert Xu 3536623e3b2SEric Dumazet ecn = ip4_frag_ecn(ip_hdr(skb)->tos); 354eddc9ec5SArnaldo Carvalho de Melo offset = ntohs(ip_hdr(skb)->frag_off); 3551da177e4SLinus Torvalds flags = offset & ~IP_OFFSET; 3561da177e4SLinus Torvalds offset &= IP_OFFSET; 3571da177e4SLinus Torvalds offset <<= 3; /* offset is in 8-byte chunks */ 358c9bdd4b5SArnaldo Carvalho de Melo ihl = ip_hdrlen(skb); 3591da177e4SLinus Torvalds 3601da177e4SLinus Torvalds /* Determine the position of this fragment. */ 3611da177e4SLinus Torvalds end = offset + skb->len - ihl; 3621706d587SHerbert Xu err = -EINVAL; 3631da177e4SLinus Torvalds 3641da177e4SLinus Torvalds /* Is this the final fragment? */ 3651da177e4SLinus Torvalds if ((flags & IP_MF) == 0) { 3661da177e4SLinus Torvalds /* If we already have some bits beyond end 36742b2aa86SJustin P. Mattock * or have different end, the segment is corrupted. 3681da177e4SLinus Torvalds */ 3695ab11c98SPavel Emelyanov if (end < qp->q.len || 370bc578a54SJoe Perches ((qp->q.last_in & INET_FRAG_LAST_IN) && end != qp->q.len)) 3711da177e4SLinus Torvalds goto err; 372bc578a54SJoe Perches qp->q.last_in |= INET_FRAG_LAST_IN; 3735ab11c98SPavel Emelyanov qp->q.len = end; 3741da177e4SLinus Torvalds } else { 3751da177e4SLinus Torvalds if (end&7) { 3761da177e4SLinus Torvalds end &= ~7; 3771da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 3781da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 3791da177e4SLinus Torvalds } 3805ab11c98SPavel Emelyanov if (end > qp->q.len) { 3811da177e4SLinus Torvalds /* Some bits beyond end -> corruption. */ 382bc578a54SJoe Perches if (qp->q.last_in & INET_FRAG_LAST_IN) 3831da177e4SLinus Torvalds goto err; 3845ab11c98SPavel Emelyanov qp->q.len = end; 3851da177e4SLinus Torvalds } 3861da177e4SLinus Torvalds } 3871da177e4SLinus Torvalds if (end == offset) 3881da177e4SLinus Torvalds goto err; 3891da177e4SLinus Torvalds 3901706d587SHerbert Xu err = -ENOMEM; 3911da177e4SLinus Torvalds if (pskb_pull(skb, ihl) == NULL) 3921da177e4SLinus Torvalds goto err; 3931706d587SHerbert Xu 3941706d587SHerbert Xu err = pskb_trim_rcsum(skb, end - offset); 3951706d587SHerbert Xu if (err) 3961da177e4SLinus Torvalds goto err; 3971da177e4SLinus Torvalds 3981da177e4SLinus Torvalds /* Find out which fragments are in front and at the back of us 3991da177e4SLinus Torvalds * in the chain of fragments so far. We must know where to put 4001da177e4SLinus Torvalds * this fragment, right? 4011da177e4SLinus Torvalds */ 402d6bebca9SChangli Gao prev = qp->q.fragments_tail; 403d6bebca9SChangli Gao if (!prev || FRAG_CB(prev)->offset < offset) { 404d6bebca9SChangli Gao next = NULL; 405d6bebca9SChangli Gao goto found; 406d6bebca9SChangli Gao } 4071da177e4SLinus Torvalds prev = NULL; 4085ab11c98SPavel Emelyanov for (next = qp->q.fragments; next != NULL; next = next->next) { 4091da177e4SLinus Torvalds if (FRAG_CB(next)->offset >= offset) 4101da177e4SLinus Torvalds break; /* bingo! */ 4111da177e4SLinus Torvalds prev = next; 4121da177e4SLinus Torvalds } 4131da177e4SLinus Torvalds 414d6bebca9SChangli Gao found: 4151da177e4SLinus Torvalds /* We found where to put this one. Check for overlap with 4161da177e4SLinus Torvalds * preceding fragment, and, if needed, align things so that 4171da177e4SLinus Torvalds * any overlaps are eliminated. 4181da177e4SLinus Torvalds */ 4191da177e4SLinus Torvalds if (prev) { 4201da177e4SLinus Torvalds int i = (FRAG_CB(prev)->offset + prev->len) - offset; 4211da177e4SLinus Torvalds 4221da177e4SLinus Torvalds if (i > 0) { 4231da177e4SLinus Torvalds offset += i; 4241706d587SHerbert Xu err = -EINVAL; 4251da177e4SLinus Torvalds if (end <= offset) 4261da177e4SLinus Torvalds goto err; 4271706d587SHerbert Xu err = -ENOMEM; 4281da177e4SLinus Torvalds if (!pskb_pull(skb, i)) 4291da177e4SLinus Torvalds goto err; 4301da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 4311da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 4321da177e4SLinus Torvalds } 4331da177e4SLinus Torvalds } 4341da177e4SLinus Torvalds 4351706d587SHerbert Xu err = -ENOMEM; 4361706d587SHerbert Xu 4371da177e4SLinus Torvalds while (next && FRAG_CB(next)->offset < end) { 4381da177e4SLinus Torvalds int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */ 4391da177e4SLinus Torvalds 4401da177e4SLinus Torvalds if (i < next->len) { 4411da177e4SLinus Torvalds /* Eat head of the next overlapped fragment 4421da177e4SLinus Torvalds * and leave the loop. The next ones cannot overlap. 4431da177e4SLinus Torvalds */ 4441da177e4SLinus Torvalds if (!pskb_pull(next, i)) 4451da177e4SLinus Torvalds goto err; 4461da177e4SLinus Torvalds FRAG_CB(next)->offset += i; 4475ab11c98SPavel Emelyanov qp->q.meat -= i; 4481da177e4SLinus Torvalds if (next->ip_summed != CHECKSUM_UNNECESSARY) 4491da177e4SLinus Torvalds next->ip_summed = CHECKSUM_NONE; 4501da177e4SLinus Torvalds break; 4511da177e4SLinus Torvalds } else { 4521da177e4SLinus Torvalds struct sk_buff *free_it = next; 4531da177e4SLinus Torvalds 45447c6bf77SPeter Zijlstra /* Old fragment is completely overridden with 4551da177e4SLinus Torvalds * new one drop it. 4561da177e4SLinus Torvalds */ 4571da177e4SLinus Torvalds next = next->next; 4581da177e4SLinus Torvalds 4591da177e4SLinus Torvalds if (prev) 4601da177e4SLinus Torvalds prev->next = next; 4611da177e4SLinus Torvalds else 4625ab11c98SPavel Emelyanov qp->q.fragments = next; 4631da177e4SLinus Torvalds 4645ab11c98SPavel Emelyanov qp->q.meat -= free_it->len; 465d433673eSJesper Dangaard Brouer sub_frag_mem_limit(&qp->q, free_it->truesize); 466d433673eSJesper Dangaard Brouer kfree_skb(free_it); 4671da177e4SLinus Torvalds } 4681da177e4SLinus Torvalds } 4691da177e4SLinus Torvalds 4701da177e4SLinus Torvalds FRAG_CB(skb)->offset = offset; 4711da177e4SLinus Torvalds 4721da177e4SLinus Torvalds /* Insert this fragment in the chain of fragments. */ 4731da177e4SLinus Torvalds skb->next = next; 474d6bebca9SChangli Gao if (!next) 475d6bebca9SChangli Gao qp->q.fragments_tail = skb; 4761da177e4SLinus Torvalds if (prev) 4771da177e4SLinus Torvalds prev->next = skb; 4781da177e4SLinus Torvalds else 4795ab11c98SPavel Emelyanov qp->q.fragments = skb; 4801da177e4SLinus Torvalds 4811706d587SHerbert Xu dev = skb->dev; 4821706d587SHerbert Xu if (dev) { 4831706d587SHerbert Xu qp->iif = dev->ifindex; 4841da177e4SLinus Torvalds skb->dev = NULL; 4851706d587SHerbert Xu } 4865ab11c98SPavel Emelyanov qp->q.stamp = skb->tstamp; 4875ab11c98SPavel Emelyanov qp->q.meat += skb->len; 4886623e3b2SEric Dumazet qp->ecn |= ecn; 489d433673eSJesper Dangaard Brouer add_frag_mem_limit(&qp->q, skb->truesize); 4901da177e4SLinus Torvalds if (offset == 0) 491bc578a54SJoe Perches qp->q.last_in |= INET_FRAG_FIRST_IN; 4921da177e4SLinus Torvalds 4935f2d04f1SPatrick McHardy if (ip_hdr(skb)->frag_off & htons(IP_DF) && 4945f2d04f1SPatrick McHardy skb->len + ihl > qp->q.max_size) 4955f2d04f1SPatrick McHardy qp->q.max_size = skb->len + ihl; 4965f2d04f1SPatrick McHardy 497bc578a54SJoe Perches if (qp->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && 49897599dc7SEric Dumazet qp->q.meat == qp->q.len) { 49997599dc7SEric Dumazet unsigned long orefdst = skb->_skb_refdst; 5001706d587SHerbert Xu 50197599dc7SEric Dumazet skb->_skb_refdst = 0UL; 50297599dc7SEric Dumazet err = ip_frag_reasm(qp, prev, dev); 50397599dc7SEric Dumazet skb->_skb_refdst = orefdst; 50497599dc7SEric Dumazet return err; 50597599dc7SEric Dumazet } 50697599dc7SEric Dumazet 50797599dc7SEric Dumazet skb_dst_drop(skb); 5083ef0eb0dSJesper Dangaard Brouer inet_frag_lru_move(&qp->q); 5091706d587SHerbert Xu return -EINPROGRESS; 5101da177e4SLinus Torvalds 5111da177e4SLinus Torvalds err: 5121da177e4SLinus Torvalds kfree_skb(skb); 5131706d587SHerbert Xu return err; 5141da177e4SLinus Torvalds } 5151da177e4SLinus Torvalds 5161da177e4SLinus Torvalds 5171da177e4SLinus Torvalds /* Build a new IP datagram from all its fragments. */ 5181da177e4SLinus Torvalds 5191706d587SHerbert Xu static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 5201706d587SHerbert Xu struct net_device *dev) 5211da177e4SLinus Torvalds { 5222bad35b7SJorge Boncompte [DTI2] struct net *net = container_of(qp->q.net, struct net, ipv4.frags); 5231da177e4SLinus Torvalds struct iphdr *iph; 5245ab11c98SPavel Emelyanov struct sk_buff *fp, *head = qp->q.fragments; 5251da177e4SLinus Torvalds int len; 5261da177e4SLinus Torvalds int ihlen; 5271706d587SHerbert Xu int err; 5283cc49492SEric Dumazet int sum_truesize; 5295173cc05SEric Dumazet u8 ecn; 5301da177e4SLinus Torvalds 5311da177e4SLinus Torvalds ipq_kill(qp); 5321da177e4SLinus Torvalds 533be991971SHannes Frederic Sowa ecn = ip_frag_ecn_table[qp->ecn]; 5345173cc05SEric Dumazet if (unlikely(ecn == 0xff)) { 5355173cc05SEric Dumazet err = -EINVAL; 5365173cc05SEric Dumazet goto out_fail; 5375173cc05SEric Dumazet } 5381706d587SHerbert Xu /* Make the one we just received the head. */ 5391706d587SHerbert Xu if (prev) { 5401706d587SHerbert Xu head = prev->next; 5411706d587SHerbert Xu fp = skb_clone(head, GFP_ATOMIC); 5421706d587SHerbert Xu if (!fp) 5431706d587SHerbert Xu goto out_nomem; 5441706d587SHerbert Xu 5451706d587SHerbert Xu fp->next = head->next; 546d6bebca9SChangli Gao if (!fp->next) 547d6bebca9SChangli Gao qp->q.fragments_tail = fp; 5481706d587SHerbert Xu prev->next = fp; 5491706d587SHerbert Xu 5505ab11c98SPavel Emelyanov skb_morph(head, qp->q.fragments); 5515ab11c98SPavel Emelyanov head->next = qp->q.fragments->next; 5521706d587SHerbert Xu 553cbf8f7bbSEric Dumazet consume_skb(qp->q.fragments); 5545ab11c98SPavel Emelyanov qp->q.fragments = head; 5551706d587SHerbert Xu } 5561706d587SHerbert Xu 557547b792cSIlpo Järvinen WARN_ON(head == NULL); 558547b792cSIlpo Järvinen WARN_ON(FRAG_CB(head)->offset != 0); 5591da177e4SLinus Torvalds 5601da177e4SLinus Torvalds /* Allocate a new buffer for the datagram. */ 561c9bdd4b5SArnaldo Carvalho de Melo ihlen = ip_hdrlen(head); 5625ab11c98SPavel Emelyanov len = ihlen + qp->q.len; 5631da177e4SLinus Torvalds 5641706d587SHerbert Xu err = -E2BIG; 5651da177e4SLinus Torvalds if (len > 65535) 5661da177e4SLinus Torvalds goto out_oversize; 5671da177e4SLinus Torvalds 5681da177e4SLinus Torvalds /* Head of list must not be cloned. */ 56914bbd6a5SPravin B Shelar if (skb_unclone(head, GFP_ATOMIC)) 5701da177e4SLinus Torvalds goto out_nomem; 5711da177e4SLinus Torvalds 5721da177e4SLinus Torvalds /* If the first fragment is fragmented itself, we split 5731da177e4SLinus Torvalds * it to two chunks: the first with data and paged part 5741da177e4SLinus Torvalds * and the second, holding only fragments. */ 57521dc3301SDavid S. Miller if (skb_has_frag_list(head)) { 5761da177e4SLinus Torvalds struct sk_buff *clone; 5771da177e4SLinus Torvalds int i, plen = 0; 5781da177e4SLinus Torvalds 5791da177e4SLinus Torvalds if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) 5801da177e4SLinus Torvalds goto out_nomem; 5811da177e4SLinus Torvalds clone->next = head->next; 5821da177e4SLinus Torvalds head->next = clone; 5831da177e4SLinus Torvalds skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 584d7fcf1a5SDavid S. Miller skb_frag_list_init(head); 5851da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(head)->nr_frags; i++) 5869e903e08SEric Dumazet plen += skb_frag_size(&skb_shinfo(head)->frags[i]); 5871da177e4SLinus Torvalds clone->len = clone->data_len = head->data_len - plen; 5881da177e4SLinus Torvalds head->data_len -= clone->len; 5891da177e4SLinus Torvalds head->len -= clone->len; 5901da177e4SLinus Torvalds clone->csum = 0; 5911da177e4SLinus Torvalds clone->ip_summed = head->ip_summed; 592d433673eSJesper Dangaard Brouer add_frag_mem_limit(&qp->q, clone->truesize); 5931da177e4SLinus Torvalds } 5941da177e4SLinus Torvalds 595d56f90a7SArnaldo Carvalho de Melo skb_push(head, head->data - skb_network_header(head)); 5961da177e4SLinus Torvalds 5973cc49492SEric Dumazet sum_truesize = head->truesize; 5983cc49492SEric Dumazet for (fp = head->next; fp;) { 5993cc49492SEric Dumazet bool headstolen; 6003cc49492SEric Dumazet int delta; 6013cc49492SEric Dumazet struct sk_buff *next = fp->next; 6023cc49492SEric Dumazet 6033cc49492SEric Dumazet sum_truesize += fp->truesize; 6041da177e4SLinus Torvalds if (head->ip_summed != fp->ip_summed) 6051da177e4SLinus Torvalds head->ip_summed = CHECKSUM_NONE; 60684fa7933SPatrick McHardy else if (head->ip_summed == CHECKSUM_COMPLETE) 6071da177e4SLinus Torvalds head->csum = csum_add(head->csum, fp->csum); 6083cc49492SEric Dumazet 6093cc49492SEric Dumazet if (skb_try_coalesce(head, fp, &headstolen, &delta)) { 6103cc49492SEric Dumazet kfree_skb_partial(fp, headstolen); 6113cc49492SEric Dumazet } else { 6123cc49492SEric Dumazet if (!skb_shinfo(head)->frag_list) 6133cc49492SEric Dumazet skb_shinfo(head)->frag_list = fp; 6143cc49492SEric Dumazet head->data_len += fp->len; 6153cc49492SEric Dumazet head->len += fp->len; 6161da177e4SLinus Torvalds head->truesize += fp->truesize; 6171da177e4SLinus Torvalds } 6183cc49492SEric Dumazet fp = next; 6193cc49492SEric Dumazet } 620d433673eSJesper Dangaard Brouer sub_frag_mem_limit(&qp->q, sum_truesize); 6211da177e4SLinus Torvalds 6221da177e4SLinus Torvalds head->next = NULL; 6231da177e4SLinus Torvalds head->dev = dev; 6245ab11c98SPavel Emelyanov head->tstamp = qp->q.stamp; 6255f2d04f1SPatrick McHardy IPCB(head)->frag_max_size = qp->q.max_size; 6261da177e4SLinus Torvalds 627eddc9ec5SArnaldo Carvalho de Melo iph = ip_hdr(head); 6285f2d04f1SPatrick McHardy /* max_size != 0 implies at least one fragment had IP_DF set */ 6295f2d04f1SPatrick McHardy iph->frag_off = qp->q.max_size ? htons(IP_DF) : 0; 6301da177e4SLinus Torvalds iph->tot_len = htons(len); 6315173cc05SEric Dumazet iph->tos |= ecn; 6322bad35b7SJorge Boncompte [DTI2] IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS); 6335ab11c98SPavel Emelyanov qp->q.fragments = NULL; 634d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 6351706d587SHerbert Xu return 0; 6361da177e4SLinus Torvalds 6371da177e4SLinus Torvalds out_nomem: 638afd46503SJoe Perches LIMIT_NETDEBUG(KERN_ERR pr_fmt("queue_glue: no memory for gluing queue %p\n"), 639afd46503SJoe Perches qp); 64045542479SDavid Howells err = -ENOMEM; 6411da177e4SLinus Torvalds goto out_fail; 6421da177e4SLinus Torvalds out_oversize: 643e87cc472SJoe Perches net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->saddr); 6441da177e4SLinus Torvalds out_fail: 645bbf31bf1SDavid Ford IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 6461706d587SHerbert Xu return err; 6471da177e4SLinus Torvalds } 6481da177e4SLinus Torvalds 6491da177e4SLinus Torvalds /* Process an incoming IP datagram fragment. */ 650776c729eSHerbert Xu int ip_defrag(struct sk_buff *skb, u32 user) 6511da177e4SLinus Torvalds { 6521da177e4SLinus Torvalds struct ipq *qp; 653ac18e750SPavel Emelyanov struct net *net; 6541da177e4SLinus Torvalds 655adf30907SEric Dumazet net = skb->dev ? dev_net(skb->dev) : dev_net(skb_dst(skb)->dev); 6567c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMREQDS); 6571da177e4SLinus Torvalds 6581da177e4SLinus Torvalds /* Start by cleaning up the memory. */ 6596ddc0822SPavel Emelyanov ip_evictor(net); 6601da177e4SLinus Torvalds 6611da177e4SLinus Torvalds /* Lookup (or create) queue header */ 662ac18e750SPavel Emelyanov if ((qp = ip_find(net, ip_hdr(skb), user)) != NULL) { 6631706d587SHerbert Xu int ret; 6641da177e4SLinus Torvalds 6655ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 6661da177e4SLinus Torvalds 6671706d587SHerbert Xu ret = ip_frag_queue(qp, skb); 6681da177e4SLinus Torvalds 6695ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 6704b6cb5d8SPavel Emelyanov ipq_put(qp); 671776c729eSHerbert Xu return ret; 6721da177e4SLinus Torvalds } 6731da177e4SLinus Torvalds 6747c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 6751da177e4SLinus Torvalds kfree_skb(skb); 676776c729eSHerbert Xu return -ENOMEM; 6771da177e4SLinus Torvalds } 6784bc2f18bSEric Dumazet EXPORT_SYMBOL(ip_defrag); 6791da177e4SLinus Torvalds 680bc416d97SEric Dumazet struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) 681bc416d97SEric Dumazet { 6821bf3751eSJohannes Berg struct iphdr iph; 683bc416d97SEric Dumazet u32 len; 684bc416d97SEric Dumazet 685bc416d97SEric Dumazet if (skb->protocol != htons(ETH_P_IP)) 686bc416d97SEric Dumazet return skb; 687bc416d97SEric Dumazet 6881bf3751eSJohannes Berg if (!skb_copy_bits(skb, 0, &iph, sizeof(iph))) 689bc416d97SEric Dumazet return skb; 690bc416d97SEric Dumazet 6911bf3751eSJohannes Berg if (iph.ihl < 5 || iph.version != 4) 692bc416d97SEric Dumazet return skb; 693bc416d97SEric Dumazet 6941bf3751eSJohannes Berg len = ntohs(iph.tot_len); 6951bf3751eSJohannes Berg if (skb->len < len || len < (iph.ihl * 4)) 6961bf3751eSJohannes Berg return skb; 6971bf3751eSJohannes Berg 6981bf3751eSJohannes Berg if (ip_is_fragment(&iph)) { 699bc416d97SEric Dumazet skb = skb_share_check(skb, GFP_ATOMIC); 700bc416d97SEric Dumazet if (skb) { 7011bf3751eSJohannes Berg if (!pskb_may_pull(skb, iph.ihl*4)) 7021bf3751eSJohannes Berg return skb; 703bc416d97SEric Dumazet if (pskb_trim_rcsum(skb, len)) 704bc416d97SEric Dumazet return skb; 705bc416d97SEric Dumazet memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 706bc416d97SEric Dumazet if (ip_defrag(skb, user)) 707bc416d97SEric Dumazet return NULL; 7087539fadcSTom Herbert skb_clear_hash(skb); 709bc416d97SEric Dumazet } 710bc416d97SEric Dumazet } 711bc416d97SEric Dumazet return skb; 712bc416d97SEric Dumazet } 713bc416d97SEric Dumazet EXPORT_SYMBOL(ip_check_defrag); 714bc416d97SEric Dumazet 7158d8354d2SPavel Emelyanov #ifdef CONFIG_SYSCTL 7168d8354d2SPavel Emelyanov static int zero; 7178d8354d2SPavel Emelyanov 7180a64b4b8SPavel Emelyanov static struct ctl_table ip4_frags_ns_ctl_table[] = { 7198d8354d2SPavel Emelyanov { 7208d8354d2SPavel Emelyanov .procname = "ipfrag_high_thresh", 721e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.high_thresh, 7228d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7238d8354d2SPavel Emelyanov .mode = 0644, 7246d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec 7258d8354d2SPavel Emelyanov }, 7268d8354d2SPavel Emelyanov { 7278d8354d2SPavel Emelyanov .procname = "ipfrag_low_thresh", 728e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.low_thresh, 7298d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7308d8354d2SPavel Emelyanov .mode = 0644, 7316d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec 7328d8354d2SPavel Emelyanov }, 7338d8354d2SPavel Emelyanov { 7348d8354d2SPavel Emelyanov .procname = "ipfrag_time", 735b2fd5321SPavel Emelyanov .data = &init_net.ipv4.frags.timeout, 7368d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7378d8354d2SPavel Emelyanov .mode = 0644, 7386d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7398d8354d2SPavel Emelyanov }, 7407d291ebbSPavel Emelyanov { } 7417d291ebbSPavel Emelyanov }; 7427d291ebbSPavel Emelyanov 7437d291ebbSPavel Emelyanov static struct ctl_table ip4_frags_ctl_table[] = { 7448d8354d2SPavel Emelyanov { 7458d8354d2SPavel Emelyanov .procname = "ipfrag_secret_interval", 7463b4bc4a2SPavel Emelyanov .data = &ip4_frags.secret_interval, 7478d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7488d8354d2SPavel Emelyanov .mode = 0644, 7496d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7508d8354d2SPavel Emelyanov }, 7518d8354d2SPavel Emelyanov { 7528d8354d2SPavel Emelyanov .procname = "ipfrag_max_dist", 7538d8354d2SPavel Emelyanov .data = &sysctl_ipfrag_max_dist, 7548d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7558d8354d2SPavel Emelyanov .mode = 0644, 7566d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_minmax, 7578d8354d2SPavel Emelyanov .extra1 = &zero 7588d8354d2SPavel Emelyanov }, 7598d8354d2SPavel Emelyanov { } 7608d8354d2SPavel Emelyanov }; 7618d8354d2SPavel Emelyanov 7622c8c1e72SAlexey Dobriyan static int __net_init ip4_frags_ns_ctl_register(struct net *net) 7638d8354d2SPavel Emelyanov { 764e4a2d5c2SPavel Emelyanov struct ctl_table *table; 7658d8354d2SPavel Emelyanov struct ctl_table_header *hdr; 7668d8354d2SPavel Emelyanov 7670a64b4b8SPavel Emelyanov table = ip4_frags_ns_ctl_table; 76809ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) { 7690a64b4b8SPavel Emelyanov table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL); 770e4a2d5c2SPavel Emelyanov if (table == NULL) 771e4a2d5c2SPavel Emelyanov goto err_alloc; 772e4a2d5c2SPavel Emelyanov 773e31e0bdcSPavel Emelyanov table[0].data = &net->ipv4.frags.high_thresh; 774e31e0bdcSPavel Emelyanov table[1].data = &net->ipv4.frags.low_thresh; 775b2fd5321SPavel Emelyanov table[2].data = &net->ipv4.frags.timeout; 776464dc801SEric W. Biederman 777464dc801SEric W. Biederman /* Don't export sysctls to unprivileged users */ 778464dc801SEric W. Biederman if (net->user_ns != &init_user_ns) 779464dc801SEric W. Biederman table[0].procname = NULL; 780e4a2d5c2SPavel Emelyanov } 781e4a2d5c2SPavel Emelyanov 782ec8f23ceSEric W. Biederman hdr = register_net_sysctl(net, "net/ipv4", table); 783e4a2d5c2SPavel Emelyanov if (hdr == NULL) 784e4a2d5c2SPavel Emelyanov goto err_reg; 785e4a2d5c2SPavel Emelyanov 786e4a2d5c2SPavel Emelyanov net->ipv4.frags_hdr = hdr; 787e4a2d5c2SPavel Emelyanov return 0; 788e4a2d5c2SPavel Emelyanov 789e4a2d5c2SPavel Emelyanov err_reg: 79009ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) 791e4a2d5c2SPavel Emelyanov kfree(table); 792e4a2d5c2SPavel Emelyanov err_alloc: 793e4a2d5c2SPavel Emelyanov return -ENOMEM; 794e4a2d5c2SPavel Emelyanov } 795e4a2d5c2SPavel Emelyanov 7962c8c1e72SAlexey Dobriyan static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net) 797e4a2d5c2SPavel Emelyanov { 798e4a2d5c2SPavel Emelyanov struct ctl_table *table; 799e4a2d5c2SPavel Emelyanov 800e4a2d5c2SPavel Emelyanov table = net->ipv4.frags_hdr->ctl_table_arg; 801e4a2d5c2SPavel Emelyanov unregister_net_sysctl_table(net->ipv4.frags_hdr); 802e4a2d5c2SPavel Emelyanov kfree(table); 8038d8354d2SPavel Emelyanov } 8047d291ebbSPavel Emelyanov 8057d291ebbSPavel Emelyanov static void ip4_frags_ctl_register(void) 8067d291ebbSPavel Emelyanov { 80743444757SEric W. Biederman register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table); 8087d291ebbSPavel Emelyanov } 8098d8354d2SPavel Emelyanov #else 8100a64b4b8SPavel Emelyanov static inline int ip4_frags_ns_ctl_register(struct net *net) 8118d8354d2SPavel Emelyanov { 8128d8354d2SPavel Emelyanov return 0; 8138d8354d2SPavel Emelyanov } 814e4a2d5c2SPavel Emelyanov 8150a64b4b8SPavel Emelyanov static inline void ip4_frags_ns_ctl_unregister(struct net *net) 816e4a2d5c2SPavel Emelyanov { 817e4a2d5c2SPavel Emelyanov } 8187d291ebbSPavel Emelyanov 8197d291ebbSPavel Emelyanov static inline void ip4_frags_ctl_register(void) 8207d291ebbSPavel Emelyanov { 8217d291ebbSPavel Emelyanov } 8228d8354d2SPavel Emelyanov #endif 8238d8354d2SPavel Emelyanov 8242c8c1e72SAlexey Dobriyan static int __net_init ipv4_frags_init_net(struct net *net) 8258d8354d2SPavel Emelyanov { 826c2a93660SJesper Dangaard Brouer /* Fragment cache limits. 827c2a93660SJesper Dangaard Brouer * 828c2a93660SJesper Dangaard Brouer * The fragment memory accounting code, (tries to) account for 829c2a93660SJesper Dangaard Brouer * the real memory usage, by measuring both the size of frag 830c2a93660SJesper Dangaard Brouer * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) 831c2a93660SJesper Dangaard Brouer * and the SKB's truesize. 832c2a93660SJesper Dangaard Brouer * 833c2a93660SJesper Dangaard Brouer * A 64K fragment consumes 129736 bytes (44*2944)+200 834c2a93660SJesper Dangaard Brouer * (1500 truesize == 2944, sizeof(struct ipq) == 200) 835c2a93660SJesper Dangaard Brouer * 836c2a93660SJesper Dangaard Brouer * We will commit 4MB at one time. Should we cross that limit 837c2a93660SJesper Dangaard Brouer * we will prune down to 3MB, making room for approx 8 big 64K 838c2a93660SJesper Dangaard Brouer * fragments 8x128k. 839e31e0bdcSPavel Emelyanov */ 840c2a93660SJesper Dangaard Brouer net->ipv4.frags.high_thresh = 4 * 1024 * 1024; 841c2a93660SJesper Dangaard Brouer net->ipv4.frags.low_thresh = 3 * 1024 * 1024; 842e31e0bdcSPavel Emelyanov /* 843b2fd5321SPavel Emelyanov * Important NOTE! Fragment queue must be destroyed before MSL expires. 844b2fd5321SPavel Emelyanov * RFC791 is wrong proposing to prolongate timer each fragment arrival 845b2fd5321SPavel Emelyanov * by TTL. 846b2fd5321SPavel Emelyanov */ 847b2fd5321SPavel Emelyanov net->ipv4.frags.timeout = IP_FRAG_TIME; 848b2fd5321SPavel Emelyanov 849e5a2bb84SPavel Emelyanov inet_frags_init_net(&net->ipv4.frags); 850e5a2bb84SPavel Emelyanov 8510a64b4b8SPavel Emelyanov return ip4_frags_ns_ctl_register(net); 8528d8354d2SPavel Emelyanov } 8538d8354d2SPavel Emelyanov 8542c8c1e72SAlexey Dobriyan static void __net_exit ipv4_frags_exit_net(struct net *net) 85581566e83SPavel Emelyanov { 8560a64b4b8SPavel Emelyanov ip4_frags_ns_ctl_unregister(net); 85781566e83SPavel Emelyanov inet_frags_exit_net(&net->ipv4.frags, &ip4_frags); 85881566e83SPavel Emelyanov } 85981566e83SPavel Emelyanov 86081566e83SPavel Emelyanov static struct pernet_operations ip4_frags_ops = { 86181566e83SPavel Emelyanov .init = ipv4_frags_init_net, 86281566e83SPavel Emelyanov .exit = ipv4_frags_exit_net, 86381566e83SPavel Emelyanov }; 86481566e83SPavel Emelyanov 865b7aa0bf7SEric Dumazet void __init ipfrag_init(void) 8661da177e4SLinus Torvalds { 8677d291ebbSPavel Emelyanov ip4_frags_ctl_register(); 86881566e83SPavel Emelyanov register_pernet_subsys(&ip4_frags_ops); 869321a3a99SPavel Emelyanov ip4_frags.hashfn = ip4_hashfn; 870c6fda282SPavel Emelyanov ip4_frags.constructor = ip4_frag_init; 8711e4b8287SPavel Emelyanov ip4_frags.destructor = ip4_frag_free; 8721e4b8287SPavel Emelyanov ip4_frags.skb_free = NULL; 8731e4b8287SPavel Emelyanov ip4_frags.qsize = sizeof(struct ipq); 874abd6523dSPavel Emelyanov ip4_frags.match = ip4_frag_match; 875e521db9dSPavel Emelyanov ip4_frags.frag_expire = ip_expire; 8763b4bc4a2SPavel Emelyanov ip4_frags.secret_interval = 10 * 60 * HZ; 8777eb95156SPavel Emelyanov inet_frags_init(&ip4_frags); 8781da177e4SLinus Torvalds } 879