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; 58d4ad4d22SNikolay Aleksandrov static const char ip_frag_cache_name[] = "ip4-frags"; 5989cee8b1SHerbert Xu 601da177e4SLinus Torvalds struct ipfrag_skb_cb 611da177e4SLinus Torvalds { 621da177e4SLinus Torvalds struct inet_skb_parm h; 631da177e4SLinus Torvalds int offset; 641da177e4SLinus Torvalds }; 651da177e4SLinus Torvalds 661da177e4SLinus Torvalds #define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb)) 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds /* Describe an entry in the "incomplete datagrams" queue. */ 691da177e4SLinus Torvalds struct ipq { 705ab11c98SPavel Emelyanov struct inet_frag_queue q; 715ab11c98SPavel Emelyanov 721da177e4SLinus Torvalds u32 user; 7318277770SAl Viro __be32 saddr; 7418277770SAl Viro __be32 daddr; 7518277770SAl Viro __be16 id; 761da177e4SLinus Torvalds u8 protocol; 776623e3b2SEric Dumazet u8 ecn; /* RFC3168 support */ 7889cee8b1SHerbert Xu int iif; 7989cee8b1SHerbert Xu unsigned int rid; 8089cee8b1SHerbert Xu struct inet_peer *peer; 811da177e4SLinus Torvalds }; 821da177e4SLinus Torvalds 83aa1f731eSFabian Frederick static u8 ip4_frag_ecn(u8 tos) 846623e3b2SEric Dumazet { 855173cc05SEric Dumazet return 1 << (tos & INET_ECN_MASK); 866623e3b2SEric Dumazet } 876623e3b2SEric Dumazet 887eb95156SPavel Emelyanov static struct inet_frags ip4_frags; 891da177e4SLinus Torvalds 906ddc0822SPavel Emelyanov int ip_frag_mem(struct net *net) 917eb95156SPavel Emelyanov { 92d433673eSJesper Dangaard Brouer return sum_frag_mem_limit(&net->ipv4.frags); 937eb95156SPavel Emelyanov } 941da177e4SLinus Torvalds 951706d587SHerbert Xu static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 961706d587SHerbert Xu struct net_device *dev); 971706d587SHerbert Xu 98c6fda282SPavel Emelyanov struct ip4_create_arg { 99c6fda282SPavel Emelyanov struct iphdr *iph; 100c6fda282SPavel Emelyanov u32 user; 101c6fda282SPavel Emelyanov }; 102c6fda282SPavel Emelyanov 10318277770SAl Viro static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot) 1041da177e4SLinus Torvalds { 105e7b519baSHannes Frederic Sowa net_get_random_once(&ip4_frags.rnd, sizeof(ip4_frags.rnd)); 10618277770SAl Viro return jhash_3words((__force u32)id << 16 | prot, 10718277770SAl Viro (__force u32)saddr, (__force u32)daddr, 108fb3cfe6eSFlorian Westphal ip4_frags.rnd); 1091da177e4SLinus Torvalds } 1101da177e4SLinus Torvalds 11136c77782SFlorian Westphal static unsigned int ip4_hashfn(const struct inet_frag_queue *q) 1121da177e4SLinus Torvalds { 11336c77782SFlorian Westphal const struct ipq *ipq; 1141da177e4SLinus Torvalds 115321a3a99SPavel Emelyanov ipq = container_of(q, struct ipq, q); 116321a3a99SPavel Emelyanov return ipqhashfn(ipq->id, ipq->saddr, ipq->daddr, ipq->protocol); 1171da177e4SLinus Torvalds } 1181da177e4SLinus Torvalds 11936c77782SFlorian Westphal static bool ip4_frag_match(const struct inet_frag_queue *q, const void *a) 120abd6523dSPavel Emelyanov { 12136c77782SFlorian Westphal const struct ipq *qp; 12236c77782SFlorian Westphal const struct ip4_create_arg *arg = a; 123abd6523dSPavel Emelyanov 124abd6523dSPavel Emelyanov qp = container_of(q, struct ipq, q); 125a02cec21SEric Dumazet return qp->id == arg->iph->id && 126abd6523dSPavel Emelyanov qp->saddr == arg->iph->saddr && 127abd6523dSPavel Emelyanov qp->daddr == arg->iph->daddr && 128abd6523dSPavel Emelyanov qp->protocol == arg->iph->protocol && 129a02cec21SEric Dumazet qp->user == arg->user; 130abd6523dSPavel Emelyanov } 131abd6523dSPavel Emelyanov 13236c77782SFlorian Westphal static void ip4_frag_init(struct inet_frag_queue *q, const void *a) 133c6fda282SPavel Emelyanov { 134c6fda282SPavel Emelyanov struct ipq *qp = container_of(q, struct ipq, q); 13554db0cc2SGao feng struct netns_ipv4 *ipv4 = container_of(q->net, struct netns_ipv4, 13654db0cc2SGao feng frags); 13754db0cc2SGao feng struct net *net = container_of(ipv4, struct net, ipv4); 13854db0cc2SGao feng 13936c77782SFlorian Westphal const struct ip4_create_arg *arg = a; 140c6fda282SPavel Emelyanov 141c6fda282SPavel Emelyanov qp->protocol = arg->iph->protocol; 142c6fda282SPavel Emelyanov qp->id = arg->iph->id; 1436623e3b2SEric Dumazet qp->ecn = ip4_frag_ecn(arg->iph->tos); 144c6fda282SPavel Emelyanov qp->saddr = arg->iph->saddr; 145c6fda282SPavel Emelyanov qp->daddr = arg->iph->daddr; 146c6fda282SPavel Emelyanov qp->user = arg->user; 147c6fda282SPavel Emelyanov qp->peer = sysctl_ipfrag_max_dist ? 148c0efc887SDavid S. Miller inet_getpeer_v4(net->ipv4.peers, arg->iph->saddr, 1) : NULL; 149c6fda282SPavel Emelyanov } 150c6fda282SPavel Emelyanov 151aa1f731eSFabian Frederick static void ip4_frag_free(struct inet_frag_queue *q) 1521da177e4SLinus Torvalds { 1531e4b8287SPavel Emelyanov struct ipq *qp; 1541e4b8287SPavel Emelyanov 1551e4b8287SPavel Emelyanov qp = container_of(q, struct ipq, q); 1561e4b8287SPavel Emelyanov if (qp->peer) 1571e4b8287SPavel Emelyanov inet_putpeer(qp->peer); 1581da177e4SLinus Torvalds } 1591da177e4SLinus Torvalds 1601da177e4SLinus Torvalds 1611da177e4SLinus Torvalds /* Destruction primitives. */ 1621da177e4SLinus Torvalds 163aa1f731eSFabian Frederick static void ipq_put(struct ipq *ipq) 1641da177e4SLinus Torvalds { 165762cc408SPavel Emelyanov inet_frag_put(&ipq->q, &ip4_frags); 1661da177e4SLinus Torvalds } 1671da177e4SLinus Torvalds 1681da177e4SLinus Torvalds /* Kill ipq entry. It is not destroyed immediately, 1691da177e4SLinus Torvalds * because caller (and someone more) holds reference count. 1701da177e4SLinus Torvalds */ 1711da177e4SLinus Torvalds static void ipq_kill(struct ipq *ipq) 1721da177e4SLinus Torvalds { 173277e650dSPavel Emelyanov inet_frag_kill(&ipq->q, &ip4_frags); 1741da177e4SLinus Torvalds } 1751da177e4SLinus Torvalds 1765cf42280SAndy Zhou static bool frag_expire_skip_icmp(u32 user) 1775cf42280SAndy Zhou { 1785cf42280SAndy Zhou return user == IP_DEFRAG_AF_PACKET || 1795cf42280SAndy Zhou ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_IN, 1805cf42280SAndy Zhou __IP_DEFRAG_CONNTRACK_IN_END); 1815cf42280SAndy Zhou } 1825cf42280SAndy Zhou 1831da177e4SLinus Torvalds /* 1841da177e4SLinus Torvalds * Oops, a fragment queue timed out. Kill it and send an ICMP reply. 1851da177e4SLinus Torvalds */ 1861da177e4SLinus Torvalds static void ip_expire(unsigned long arg) 1871da177e4SLinus Torvalds { 188e521db9dSPavel Emelyanov struct ipq *qp; 18984a3aa00SPavel Emelyanov struct net *net; 190e521db9dSPavel Emelyanov 191e521db9dSPavel Emelyanov qp = container_of((struct inet_frag_queue *) arg, struct ipq, q); 19284a3aa00SPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 1931da177e4SLinus Torvalds 1945ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 1951da177e4SLinus Torvalds 19606aa8b8aSNikolay Aleksandrov if (qp->q.flags & INET_FRAG_COMPLETE) 1971da177e4SLinus Torvalds goto out; 1981da177e4SLinus Torvalds 1991da177e4SLinus Torvalds ipq_kill(qp); 2007c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 2011da177e4SLinus Torvalds 2022e404f63SNikolay Aleksandrov if (!(qp->q.flags & INET_FRAG_EVICTED)) { 2035ab11c98SPavel Emelyanov struct sk_buff *head = qp->q.fragments; 20464f3b9e2SEric Dumazet const struct iphdr *iph; 20564f3b9e2SEric Dumazet int err; 206cb84663eSDenis V. Lunev 2072e404f63SNikolay Aleksandrov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMTIMEOUT); 2082e404f63SNikolay Aleksandrov 2092e404f63SNikolay Aleksandrov if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !qp->q.fragments) 2102e404f63SNikolay Aleksandrov goto out; 2112e404f63SNikolay Aleksandrov 21269df9d59SEric Dumazet rcu_read_lock(); 21369df9d59SEric Dumazet head->dev = dev_get_by_index_rcu(net, qp->iif); 214e9017b55SShan Wei if (!head->dev) 215e9017b55SShan Wei goto out_rcu_unlock; 216e9017b55SShan Wei 21797599dc7SEric Dumazet /* skb has no dst, perform route lookup again */ 21864f3b9e2SEric Dumazet iph = ip_hdr(head); 219c6cffba4SDavid S. Miller err = ip_route_input_noref(head, iph->daddr, iph->saddr, 220c10237e0SDavid S. Miller iph->tos, head->dev); 22164f3b9e2SEric Dumazet if (err) 222e9017b55SShan Wei goto out_rcu_unlock; 223e9017b55SShan Wei 2242e404f63SNikolay Aleksandrov /* Only an end host needs to send an ICMP 225e9017b55SShan Wei * "Fragment Reassembly Timeout" message, per RFC792. 226e9017b55SShan Wei */ 2275cf42280SAndy Zhou if (frag_expire_skip_icmp(qp->user) && 2285cf42280SAndy Zhou (skb_rtable(head)->rt_type != RTN_LOCAL)) 229e9017b55SShan Wei goto out_rcu_unlock; 230e9017b55SShan Wei 231e9017b55SShan Wei /* Send an ICMP "Fragment Reassembly Timeout" message. */ 232e9017b55SShan Wei icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); 233e9017b55SShan Wei out_rcu_unlock: 234e9017b55SShan Wei rcu_read_unlock(); 235d1c9ae6dSPatrick McHardy } 2361da177e4SLinus Torvalds out: 2375ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 2384b6cb5d8SPavel Emelyanov ipq_put(qp); 2391da177e4SLinus Torvalds } 2401da177e4SLinus Torvalds 241abd6523dSPavel Emelyanov /* Find the correct entry in the "incomplete datagrams" queue for 242abd6523dSPavel Emelyanov * this IP datagram, and create new one, if nothing is found. 243abd6523dSPavel Emelyanov */ 244aa1f731eSFabian Frederick static struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user) 2451da177e4SLinus Torvalds { 246c6fda282SPavel Emelyanov struct inet_frag_queue *q; 247c6fda282SPavel Emelyanov struct ip4_create_arg arg; 248abd6523dSPavel Emelyanov unsigned int hash; 2491da177e4SLinus Torvalds 250c6fda282SPavel Emelyanov arg.iph = iph; 251c6fda282SPavel Emelyanov arg.user = user; 2529a375803SPavel Emelyanov 253abd6523dSPavel Emelyanov hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol); 254c6fda282SPavel Emelyanov 255ac18e750SPavel Emelyanov q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash); 2565a3da1feSHannes Frederic Sowa if (IS_ERR_OR_NULL(q)) { 2575a3da1feSHannes Frederic Sowa inet_frag_maybe_warn_overflow(q, pr_fmt()); 2581da177e4SLinus Torvalds return NULL; 2591da177e4SLinus Torvalds } 2605a3da1feSHannes Frederic Sowa return container_of(q, struct ipq, q); 2615a3da1feSHannes Frederic Sowa } 2621da177e4SLinus Torvalds 26389cee8b1SHerbert Xu /* Is the fragment too far ahead to be part of ipq? */ 264aa1f731eSFabian Frederick static int ip_frag_too_far(struct ipq *qp) 26589cee8b1SHerbert Xu { 26689cee8b1SHerbert Xu struct inet_peer *peer = qp->peer; 26789cee8b1SHerbert Xu unsigned int max = sysctl_ipfrag_max_dist; 26889cee8b1SHerbert Xu unsigned int start, end; 26989cee8b1SHerbert Xu 27089cee8b1SHerbert Xu int rc; 27189cee8b1SHerbert Xu 27289cee8b1SHerbert Xu if (!peer || !max) 27389cee8b1SHerbert Xu return 0; 27489cee8b1SHerbert Xu 27589cee8b1SHerbert Xu start = qp->rid; 27689cee8b1SHerbert Xu end = atomic_inc_return(&peer->rid); 27789cee8b1SHerbert Xu qp->rid = end; 27889cee8b1SHerbert Xu 2795ab11c98SPavel Emelyanov rc = qp->q.fragments && (end - start) > max; 28089cee8b1SHerbert Xu 28189cee8b1SHerbert Xu if (rc) { 2827c73a6faSPavel Emelyanov struct net *net; 2837c73a6faSPavel Emelyanov 2847c73a6faSPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 2857c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 28689cee8b1SHerbert Xu } 28789cee8b1SHerbert Xu 28889cee8b1SHerbert Xu return rc; 28989cee8b1SHerbert Xu } 29089cee8b1SHerbert Xu 29189cee8b1SHerbert Xu static int ip_frag_reinit(struct ipq *qp) 29289cee8b1SHerbert Xu { 29389cee8b1SHerbert Xu struct sk_buff *fp; 294d433673eSJesper Dangaard Brouer unsigned int sum_truesize = 0; 29589cee8b1SHerbert Xu 296b2fd5321SPavel Emelyanov if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) { 2975ab11c98SPavel Emelyanov atomic_inc(&qp->q.refcnt); 29889cee8b1SHerbert Xu return -ETIMEDOUT; 29989cee8b1SHerbert Xu } 30089cee8b1SHerbert Xu 3015ab11c98SPavel Emelyanov fp = qp->q.fragments; 30289cee8b1SHerbert Xu do { 30389cee8b1SHerbert Xu struct sk_buff *xp = fp->next; 304d433673eSJesper Dangaard Brouer 305d433673eSJesper Dangaard Brouer sum_truesize += fp->truesize; 306d433673eSJesper Dangaard Brouer kfree_skb(fp); 30789cee8b1SHerbert Xu fp = xp; 30889cee8b1SHerbert Xu } while (fp); 309d433673eSJesper Dangaard Brouer sub_frag_mem_limit(&qp->q, sum_truesize); 31089cee8b1SHerbert Xu 31106aa8b8aSNikolay Aleksandrov qp->q.flags = 0; 3125ab11c98SPavel Emelyanov qp->q.len = 0; 3135ab11c98SPavel Emelyanov qp->q.meat = 0; 3145ab11c98SPavel Emelyanov qp->q.fragments = NULL; 315d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 31689cee8b1SHerbert Xu qp->iif = 0; 3176623e3b2SEric Dumazet qp->ecn = 0; 31889cee8b1SHerbert Xu 31989cee8b1SHerbert Xu return 0; 32089cee8b1SHerbert Xu } 32189cee8b1SHerbert Xu 3221da177e4SLinus Torvalds /* Add new segment to existing queue. */ 3231706d587SHerbert Xu static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) 3241da177e4SLinus Torvalds { 3251da177e4SLinus Torvalds struct sk_buff *prev, *next; 3261706d587SHerbert Xu struct net_device *dev; 3271da177e4SLinus Torvalds int flags, offset; 3281da177e4SLinus Torvalds int ihl, end; 3291706d587SHerbert Xu int err = -ENOENT; 3306623e3b2SEric Dumazet u8 ecn; 3311da177e4SLinus Torvalds 33206aa8b8aSNikolay Aleksandrov if (qp->q.flags & INET_FRAG_COMPLETE) 3331da177e4SLinus Torvalds goto err; 3341da177e4SLinus Torvalds 33589cee8b1SHerbert Xu if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && 3361706d587SHerbert Xu unlikely(ip_frag_too_far(qp)) && 3371706d587SHerbert Xu unlikely(err = ip_frag_reinit(qp))) { 33889cee8b1SHerbert Xu ipq_kill(qp); 33989cee8b1SHerbert Xu goto err; 34089cee8b1SHerbert Xu } 34189cee8b1SHerbert Xu 3426623e3b2SEric Dumazet ecn = ip4_frag_ecn(ip_hdr(skb)->tos); 343eddc9ec5SArnaldo Carvalho de Melo offset = ntohs(ip_hdr(skb)->frag_off); 3441da177e4SLinus Torvalds flags = offset & ~IP_OFFSET; 3451da177e4SLinus Torvalds offset &= IP_OFFSET; 3461da177e4SLinus Torvalds offset <<= 3; /* offset is in 8-byte chunks */ 347c9bdd4b5SArnaldo Carvalho de Melo ihl = ip_hdrlen(skb); 3481da177e4SLinus Torvalds 3491da177e4SLinus Torvalds /* Determine the position of this fragment. */ 3501da177e4SLinus Torvalds end = offset + skb->len - ihl; 3511706d587SHerbert Xu err = -EINVAL; 3521da177e4SLinus Torvalds 3531da177e4SLinus Torvalds /* Is this the final fragment? */ 3541da177e4SLinus Torvalds if ((flags & IP_MF) == 0) { 3551da177e4SLinus Torvalds /* If we already have some bits beyond end 35642b2aa86SJustin P. Mattock * or have different end, the segment is corrupted. 3571da177e4SLinus Torvalds */ 3585ab11c98SPavel Emelyanov if (end < qp->q.len || 35906aa8b8aSNikolay Aleksandrov ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len)) 3601da177e4SLinus Torvalds goto err; 36106aa8b8aSNikolay Aleksandrov qp->q.flags |= INET_FRAG_LAST_IN; 3625ab11c98SPavel Emelyanov qp->q.len = end; 3631da177e4SLinus Torvalds } else { 3641da177e4SLinus Torvalds if (end&7) { 3651da177e4SLinus Torvalds end &= ~7; 3661da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 3671da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 3681da177e4SLinus Torvalds } 3695ab11c98SPavel Emelyanov if (end > qp->q.len) { 3701da177e4SLinus Torvalds /* Some bits beyond end -> corruption. */ 37106aa8b8aSNikolay Aleksandrov if (qp->q.flags & INET_FRAG_LAST_IN) 3721da177e4SLinus Torvalds goto err; 3735ab11c98SPavel Emelyanov qp->q.len = end; 3741da177e4SLinus Torvalds } 3751da177e4SLinus Torvalds } 3761da177e4SLinus Torvalds if (end == offset) 3771da177e4SLinus Torvalds goto err; 3781da177e4SLinus Torvalds 3791706d587SHerbert Xu err = -ENOMEM; 38051456b29SIan Morris if (!pskb_pull(skb, ihl)) 3811da177e4SLinus Torvalds goto err; 3821706d587SHerbert Xu 3831706d587SHerbert Xu err = pskb_trim_rcsum(skb, end - offset); 3841706d587SHerbert Xu if (err) 3851da177e4SLinus Torvalds goto err; 3861da177e4SLinus Torvalds 3871da177e4SLinus Torvalds /* Find out which fragments are in front and at the back of us 3881da177e4SLinus Torvalds * in the chain of fragments so far. We must know where to put 3891da177e4SLinus Torvalds * this fragment, right? 3901da177e4SLinus Torvalds */ 391d6bebca9SChangli Gao prev = qp->q.fragments_tail; 392d6bebca9SChangli Gao if (!prev || FRAG_CB(prev)->offset < offset) { 393d6bebca9SChangli Gao next = NULL; 394d6bebca9SChangli Gao goto found; 395d6bebca9SChangli Gao } 3961da177e4SLinus Torvalds prev = NULL; 3975ab11c98SPavel Emelyanov for (next = qp->q.fragments; next != NULL; next = next->next) { 3981da177e4SLinus Torvalds if (FRAG_CB(next)->offset >= offset) 3991da177e4SLinus Torvalds break; /* bingo! */ 4001da177e4SLinus Torvalds prev = next; 4011da177e4SLinus Torvalds } 4021da177e4SLinus Torvalds 403d6bebca9SChangli Gao found: 4041da177e4SLinus Torvalds /* We found where to put this one. Check for overlap with 4051da177e4SLinus Torvalds * preceding fragment, and, if needed, align things so that 4061da177e4SLinus Torvalds * any overlaps are eliminated. 4071da177e4SLinus Torvalds */ 4081da177e4SLinus Torvalds if (prev) { 4091da177e4SLinus Torvalds int i = (FRAG_CB(prev)->offset + prev->len) - offset; 4101da177e4SLinus Torvalds 4111da177e4SLinus Torvalds if (i > 0) { 4121da177e4SLinus Torvalds offset += i; 4131706d587SHerbert Xu err = -EINVAL; 4141da177e4SLinus Torvalds if (end <= offset) 4151da177e4SLinus Torvalds goto err; 4161706d587SHerbert Xu err = -ENOMEM; 4171da177e4SLinus Torvalds if (!pskb_pull(skb, i)) 4181da177e4SLinus Torvalds goto err; 4191da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 4201da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 4211da177e4SLinus Torvalds } 4221da177e4SLinus Torvalds } 4231da177e4SLinus Torvalds 4241706d587SHerbert Xu err = -ENOMEM; 4251706d587SHerbert Xu 4261da177e4SLinus Torvalds while (next && FRAG_CB(next)->offset < end) { 4271da177e4SLinus Torvalds int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */ 4281da177e4SLinus Torvalds 4291da177e4SLinus Torvalds if (i < next->len) { 4301da177e4SLinus Torvalds /* Eat head of the next overlapped fragment 4311da177e4SLinus Torvalds * and leave the loop. The next ones cannot overlap. 4321da177e4SLinus Torvalds */ 4331da177e4SLinus Torvalds if (!pskb_pull(next, i)) 4341da177e4SLinus Torvalds goto err; 4351da177e4SLinus Torvalds FRAG_CB(next)->offset += i; 4365ab11c98SPavel Emelyanov qp->q.meat -= i; 4371da177e4SLinus Torvalds if (next->ip_summed != CHECKSUM_UNNECESSARY) 4381da177e4SLinus Torvalds next->ip_summed = CHECKSUM_NONE; 4391da177e4SLinus Torvalds break; 4401da177e4SLinus Torvalds } else { 4411da177e4SLinus Torvalds struct sk_buff *free_it = next; 4421da177e4SLinus Torvalds 44347c6bf77SPeter Zijlstra /* Old fragment is completely overridden with 4441da177e4SLinus Torvalds * new one drop it. 4451da177e4SLinus Torvalds */ 4461da177e4SLinus Torvalds next = next->next; 4471da177e4SLinus Torvalds 4481da177e4SLinus Torvalds if (prev) 4491da177e4SLinus Torvalds prev->next = next; 4501da177e4SLinus Torvalds else 4515ab11c98SPavel Emelyanov qp->q.fragments = next; 4521da177e4SLinus Torvalds 4535ab11c98SPavel Emelyanov qp->q.meat -= free_it->len; 454d433673eSJesper Dangaard Brouer sub_frag_mem_limit(&qp->q, free_it->truesize); 455d433673eSJesper Dangaard Brouer kfree_skb(free_it); 4561da177e4SLinus Torvalds } 4571da177e4SLinus Torvalds } 4581da177e4SLinus Torvalds 4591da177e4SLinus Torvalds FRAG_CB(skb)->offset = offset; 4601da177e4SLinus Torvalds 4611da177e4SLinus Torvalds /* Insert this fragment in the chain of fragments. */ 4621da177e4SLinus Torvalds skb->next = next; 463d6bebca9SChangli Gao if (!next) 464d6bebca9SChangli Gao qp->q.fragments_tail = skb; 4651da177e4SLinus Torvalds if (prev) 4661da177e4SLinus Torvalds prev->next = skb; 4671da177e4SLinus Torvalds else 4685ab11c98SPavel Emelyanov qp->q.fragments = skb; 4691da177e4SLinus Torvalds 4701706d587SHerbert Xu dev = skb->dev; 4711706d587SHerbert Xu if (dev) { 4721706d587SHerbert Xu qp->iif = dev->ifindex; 4731da177e4SLinus Torvalds skb->dev = NULL; 4741706d587SHerbert Xu } 4755ab11c98SPavel Emelyanov qp->q.stamp = skb->tstamp; 4765ab11c98SPavel Emelyanov qp->q.meat += skb->len; 4776623e3b2SEric Dumazet qp->ecn |= ecn; 478d433673eSJesper Dangaard Brouer add_frag_mem_limit(&qp->q, skb->truesize); 4791da177e4SLinus Torvalds if (offset == 0) 48006aa8b8aSNikolay Aleksandrov qp->q.flags |= INET_FRAG_FIRST_IN; 4811da177e4SLinus Torvalds 4825f2d04f1SPatrick McHardy if (ip_hdr(skb)->frag_off & htons(IP_DF) && 4835f2d04f1SPatrick McHardy skb->len + ihl > qp->q.max_size) 4845f2d04f1SPatrick McHardy qp->q.max_size = skb->len + ihl; 4855f2d04f1SPatrick McHardy 48606aa8b8aSNikolay Aleksandrov if (qp->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && 48797599dc7SEric Dumazet qp->q.meat == qp->q.len) { 48897599dc7SEric Dumazet unsigned long orefdst = skb->_skb_refdst; 4891706d587SHerbert Xu 49097599dc7SEric Dumazet skb->_skb_refdst = 0UL; 49197599dc7SEric Dumazet err = ip_frag_reasm(qp, prev, dev); 49297599dc7SEric Dumazet skb->_skb_refdst = orefdst; 49397599dc7SEric Dumazet return err; 49497599dc7SEric Dumazet } 49597599dc7SEric Dumazet 49697599dc7SEric Dumazet skb_dst_drop(skb); 4971706d587SHerbert Xu return -EINPROGRESS; 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds err: 5001da177e4SLinus Torvalds kfree_skb(skb); 5011706d587SHerbert Xu return err; 5021da177e4SLinus Torvalds } 5031da177e4SLinus Torvalds 5041da177e4SLinus Torvalds 5051da177e4SLinus Torvalds /* Build a new IP datagram from all its fragments. */ 5061da177e4SLinus Torvalds 5071706d587SHerbert Xu static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 5081706d587SHerbert Xu struct net_device *dev) 5091da177e4SLinus Torvalds { 5102bad35b7SJorge Boncompte [DTI2] struct net *net = container_of(qp->q.net, struct net, ipv4.frags); 5111da177e4SLinus Torvalds struct iphdr *iph; 5125ab11c98SPavel Emelyanov struct sk_buff *fp, *head = qp->q.fragments; 5131da177e4SLinus Torvalds int len; 5141da177e4SLinus Torvalds int ihlen; 5151706d587SHerbert Xu int err; 5163cc49492SEric Dumazet int sum_truesize; 5175173cc05SEric Dumazet u8 ecn; 5181da177e4SLinus Torvalds 5191da177e4SLinus Torvalds ipq_kill(qp); 5201da177e4SLinus Torvalds 521be991971SHannes Frederic Sowa ecn = ip_frag_ecn_table[qp->ecn]; 5225173cc05SEric Dumazet if (unlikely(ecn == 0xff)) { 5235173cc05SEric Dumazet err = -EINVAL; 5245173cc05SEric Dumazet goto out_fail; 5255173cc05SEric Dumazet } 5261706d587SHerbert Xu /* Make the one we just received the head. */ 5271706d587SHerbert Xu if (prev) { 5281706d587SHerbert Xu head = prev->next; 5291706d587SHerbert Xu fp = skb_clone(head, GFP_ATOMIC); 5301706d587SHerbert Xu if (!fp) 5311706d587SHerbert Xu goto out_nomem; 5321706d587SHerbert Xu 5331706d587SHerbert Xu fp->next = head->next; 534d6bebca9SChangli Gao if (!fp->next) 535d6bebca9SChangli Gao qp->q.fragments_tail = fp; 5361706d587SHerbert Xu prev->next = fp; 5371706d587SHerbert Xu 5385ab11c98SPavel Emelyanov skb_morph(head, qp->q.fragments); 5395ab11c98SPavel Emelyanov head->next = qp->q.fragments->next; 5401706d587SHerbert Xu 541cbf8f7bbSEric Dumazet consume_skb(qp->q.fragments); 5425ab11c98SPavel Emelyanov qp->q.fragments = head; 5431706d587SHerbert Xu } 5441706d587SHerbert Xu 54551456b29SIan Morris WARN_ON(!head); 546547b792cSIlpo Järvinen WARN_ON(FRAG_CB(head)->offset != 0); 5471da177e4SLinus Torvalds 5481da177e4SLinus Torvalds /* Allocate a new buffer for the datagram. */ 549c9bdd4b5SArnaldo Carvalho de Melo ihlen = ip_hdrlen(head); 5505ab11c98SPavel Emelyanov len = ihlen + qp->q.len; 5511da177e4SLinus Torvalds 5521706d587SHerbert Xu err = -E2BIG; 5531da177e4SLinus Torvalds if (len > 65535) 5541da177e4SLinus Torvalds goto out_oversize; 5551da177e4SLinus Torvalds 5561da177e4SLinus Torvalds /* Head of list must not be cloned. */ 55714bbd6a5SPravin B Shelar if (skb_unclone(head, GFP_ATOMIC)) 5581da177e4SLinus Torvalds goto out_nomem; 5591da177e4SLinus Torvalds 5601da177e4SLinus Torvalds /* If the first fragment is fragmented itself, we split 5611da177e4SLinus Torvalds * it to two chunks: the first with data and paged part 5621da177e4SLinus Torvalds * and the second, holding only fragments. */ 56321dc3301SDavid S. Miller if (skb_has_frag_list(head)) { 5641da177e4SLinus Torvalds struct sk_buff *clone; 5651da177e4SLinus Torvalds int i, plen = 0; 5661da177e4SLinus Torvalds 56751456b29SIan Morris clone = alloc_skb(0, GFP_ATOMIC); 56851456b29SIan Morris if (!clone) 5691da177e4SLinus Torvalds goto out_nomem; 5701da177e4SLinus Torvalds clone->next = head->next; 5711da177e4SLinus Torvalds head->next = clone; 5721da177e4SLinus Torvalds skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 573d7fcf1a5SDavid S. Miller skb_frag_list_init(head); 5741da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(head)->nr_frags; i++) 5759e903e08SEric Dumazet plen += skb_frag_size(&skb_shinfo(head)->frags[i]); 5761da177e4SLinus Torvalds clone->len = clone->data_len = head->data_len - plen; 5771da177e4SLinus Torvalds head->data_len -= clone->len; 5781da177e4SLinus Torvalds head->len -= clone->len; 5791da177e4SLinus Torvalds clone->csum = 0; 5801da177e4SLinus Torvalds clone->ip_summed = head->ip_summed; 581d433673eSJesper Dangaard Brouer add_frag_mem_limit(&qp->q, clone->truesize); 5821da177e4SLinus Torvalds } 5831da177e4SLinus Torvalds 584d56f90a7SArnaldo Carvalho de Melo skb_push(head, head->data - skb_network_header(head)); 5851da177e4SLinus Torvalds 5863cc49492SEric Dumazet sum_truesize = head->truesize; 5873cc49492SEric Dumazet for (fp = head->next; fp;) { 5883cc49492SEric Dumazet bool headstolen; 5893cc49492SEric Dumazet int delta; 5903cc49492SEric Dumazet struct sk_buff *next = fp->next; 5913cc49492SEric Dumazet 5923cc49492SEric Dumazet sum_truesize += fp->truesize; 5931da177e4SLinus Torvalds if (head->ip_summed != fp->ip_summed) 5941da177e4SLinus Torvalds head->ip_summed = CHECKSUM_NONE; 59584fa7933SPatrick McHardy else if (head->ip_summed == CHECKSUM_COMPLETE) 5961da177e4SLinus Torvalds head->csum = csum_add(head->csum, fp->csum); 5973cc49492SEric Dumazet 5983cc49492SEric Dumazet if (skb_try_coalesce(head, fp, &headstolen, &delta)) { 5993cc49492SEric Dumazet kfree_skb_partial(fp, headstolen); 6003cc49492SEric Dumazet } else { 6013cc49492SEric Dumazet if (!skb_shinfo(head)->frag_list) 6023cc49492SEric Dumazet skb_shinfo(head)->frag_list = fp; 6033cc49492SEric Dumazet head->data_len += fp->len; 6043cc49492SEric Dumazet head->len += fp->len; 6051da177e4SLinus Torvalds head->truesize += fp->truesize; 6061da177e4SLinus Torvalds } 6073cc49492SEric Dumazet fp = next; 6083cc49492SEric Dumazet } 609d433673eSJesper Dangaard Brouer sub_frag_mem_limit(&qp->q, sum_truesize); 6101da177e4SLinus Torvalds 6111da177e4SLinus Torvalds head->next = NULL; 6121da177e4SLinus Torvalds head->dev = dev; 6135ab11c98SPavel Emelyanov head->tstamp = qp->q.stamp; 6145f2d04f1SPatrick McHardy IPCB(head)->frag_max_size = qp->q.max_size; 6151da177e4SLinus Torvalds 616eddc9ec5SArnaldo Carvalho de Melo iph = ip_hdr(head); 6175f2d04f1SPatrick McHardy /* max_size != 0 implies at least one fragment had IP_DF set */ 6185f2d04f1SPatrick McHardy iph->frag_off = qp->q.max_size ? htons(IP_DF) : 0; 6191da177e4SLinus Torvalds iph->tot_len = htons(len); 6205173cc05SEric Dumazet iph->tos |= ecn; 6212bad35b7SJorge Boncompte [DTI2] IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS); 6225ab11c98SPavel Emelyanov qp->q.fragments = NULL; 623d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 6241706d587SHerbert Xu return 0; 6251da177e4SLinus Torvalds 6261da177e4SLinus Torvalds out_nomem: 627ba7a46f1SJoe Perches net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp); 62845542479SDavid Howells err = -ENOMEM; 6291da177e4SLinus Torvalds goto out_fail; 6301da177e4SLinus Torvalds out_oversize: 631e87cc472SJoe Perches net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->saddr); 6321da177e4SLinus Torvalds out_fail: 633bbf31bf1SDavid Ford IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 6341706d587SHerbert Xu return err; 6351da177e4SLinus Torvalds } 6361da177e4SLinus Torvalds 6371da177e4SLinus Torvalds /* Process an incoming IP datagram fragment. */ 638776c729eSHerbert Xu int ip_defrag(struct sk_buff *skb, u32 user) 6391da177e4SLinus Torvalds { 6401da177e4SLinus Torvalds struct ipq *qp; 641ac18e750SPavel Emelyanov struct net *net; 6421da177e4SLinus Torvalds 643adf30907SEric Dumazet net = skb->dev ? dev_net(skb->dev) : dev_net(skb_dst(skb)->dev); 6447c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMREQDS); 6451da177e4SLinus Torvalds 6461da177e4SLinus Torvalds /* Lookup (or create) queue header */ 64700db4124SIan Morris qp = ip_find(net, ip_hdr(skb), user); 64800db4124SIan Morris if (qp) { 6491706d587SHerbert Xu int ret; 6501da177e4SLinus Torvalds 6515ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 6521da177e4SLinus Torvalds 6531706d587SHerbert Xu ret = ip_frag_queue(qp, skb); 6541da177e4SLinus Torvalds 6555ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 6564b6cb5d8SPavel Emelyanov ipq_put(qp); 657776c729eSHerbert Xu return ret; 6581da177e4SLinus Torvalds } 6591da177e4SLinus Torvalds 6607c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 6611da177e4SLinus Torvalds kfree_skb(skb); 662776c729eSHerbert Xu return -ENOMEM; 6631da177e4SLinus Torvalds } 6644bc2f18bSEric Dumazet EXPORT_SYMBOL(ip_defrag); 6651da177e4SLinus Torvalds 666bc416d97SEric Dumazet struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) 667bc416d97SEric Dumazet { 6681bf3751eSJohannes Berg struct iphdr iph; 6693e32e733SAlexander Drozdov int netoff; 670bc416d97SEric Dumazet u32 len; 671bc416d97SEric Dumazet 672bc416d97SEric Dumazet if (skb->protocol != htons(ETH_P_IP)) 673bc416d97SEric Dumazet return skb; 674bc416d97SEric Dumazet 6753e32e733SAlexander Drozdov netoff = skb_network_offset(skb); 6763e32e733SAlexander Drozdov 6773e32e733SAlexander Drozdov if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0) 678bc416d97SEric Dumazet return skb; 679bc416d97SEric Dumazet 6801bf3751eSJohannes Berg if (iph.ihl < 5 || iph.version != 4) 681bc416d97SEric Dumazet return skb; 682bc416d97SEric Dumazet 6831bf3751eSJohannes Berg len = ntohs(iph.tot_len); 6843e32e733SAlexander Drozdov if (skb->len < netoff + len || len < (iph.ihl * 4)) 6851bf3751eSJohannes Berg return skb; 6861bf3751eSJohannes Berg 6871bf3751eSJohannes Berg if (ip_is_fragment(&iph)) { 688bc416d97SEric Dumazet skb = skb_share_check(skb, GFP_ATOMIC); 689bc416d97SEric Dumazet if (skb) { 6903e32e733SAlexander Drozdov if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) 6911bf3751eSJohannes Berg return skb; 6923e32e733SAlexander Drozdov if (pskb_trim_rcsum(skb, netoff + len)) 693bc416d97SEric Dumazet return skb; 694bc416d97SEric Dumazet memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 695bc416d97SEric Dumazet if (ip_defrag(skb, user)) 696bc416d97SEric Dumazet return NULL; 6977539fadcSTom Herbert skb_clear_hash(skb); 698bc416d97SEric Dumazet } 699bc416d97SEric Dumazet } 700bc416d97SEric Dumazet return skb; 701bc416d97SEric Dumazet } 702bc416d97SEric Dumazet EXPORT_SYMBOL(ip_check_defrag); 703bc416d97SEric Dumazet 7048d8354d2SPavel Emelyanov #ifdef CONFIG_SYSCTL 7058d8354d2SPavel Emelyanov static int zero; 7068d8354d2SPavel Emelyanov 7070a64b4b8SPavel Emelyanov static struct ctl_table ip4_frags_ns_ctl_table[] = { 7088d8354d2SPavel Emelyanov { 7098d8354d2SPavel Emelyanov .procname = "ipfrag_high_thresh", 710e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.high_thresh, 7118d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7128d8354d2SPavel Emelyanov .mode = 0644, 7131bab4c75SNikolay Aleksandrov .proc_handler = proc_dointvec_minmax, 7141bab4c75SNikolay Aleksandrov .extra1 = &init_net.ipv4.frags.low_thresh 7158d8354d2SPavel Emelyanov }, 7168d8354d2SPavel Emelyanov { 7178d8354d2SPavel Emelyanov .procname = "ipfrag_low_thresh", 718e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.low_thresh, 7198d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7208d8354d2SPavel Emelyanov .mode = 0644, 7211bab4c75SNikolay Aleksandrov .proc_handler = proc_dointvec_minmax, 7221bab4c75SNikolay Aleksandrov .extra1 = &zero, 7231bab4c75SNikolay Aleksandrov .extra2 = &init_net.ipv4.frags.high_thresh 7248d8354d2SPavel Emelyanov }, 7258d8354d2SPavel Emelyanov { 7268d8354d2SPavel Emelyanov .procname = "ipfrag_time", 727b2fd5321SPavel Emelyanov .data = &init_net.ipv4.frags.timeout, 7288d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7298d8354d2SPavel Emelyanov .mode = 0644, 7306d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7318d8354d2SPavel Emelyanov }, 7327d291ebbSPavel Emelyanov { } 7337d291ebbSPavel Emelyanov }; 7347d291ebbSPavel Emelyanov 735e3a57d18SFlorian Westphal /* secret interval has been deprecated */ 736e3a57d18SFlorian Westphal static int ip4_frags_secret_interval_unused; 7377d291ebbSPavel Emelyanov static struct ctl_table ip4_frags_ctl_table[] = { 7388d8354d2SPavel Emelyanov { 7398d8354d2SPavel Emelyanov .procname = "ipfrag_secret_interval", 740e3a57d18SFlorian Westphal .data = &ip4_frags_secret_interval_unused, 7418d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7428d8354d2SPavel Emelyanov .mode = 0644, 7436d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7448d8354d2SPavel Emelyanov }, 7458d8354d2SPavel Emelyanov { 7468d8354d2SPavel Emelyanov .procname = "ipfrag_max_dist", 7478d8354d2SPavel Emelyanov .data = &sysctl_ipfrag_max_dist, 7488d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7498d8354d2SPavel Emelyanov .mode = 0644, 7506d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_minmax, 7518d8354d2SPavel Emelyanov .extra1 = &zero 7528d8354d2SPavel Emelyanov }, 7538d8354d2SPavel Emelyanov { } 7548d8354d2SPavel Emelyanov }; 7558d8354d2SPavel Emelyanov 7562c8c1e72SAlexey Dobriyan static int __net_init ip4_frags_ns_ctl_register(struct net *net) 7578d8354d2SPavel Emelyanov { 758e4a2d5c2SPavel Emelyanov struct ctl_table *table; 7598d8354d2SPavel Emelyanov struct ctl_table_header *hdr; 7608d8354d2SPavel Emelyanov 7610a64b4b8SPavel Emelyanov table = ip4_frags_ns_ctl_table; 76209ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) { 7630a64b4b8SPavel Emelyanov table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL); 76451456b29SIan Morris if (!table) 765e4a2d5c2SPavel Emelyanov goto err_alloc; 766e4a2d5c2SPavel Emelyanov 767e31e0bdcSPavel Emelyanov table[0].data = &net->ipv4.frags.high_thresh; 7681bab4c75SNikolay Aleksandrov table[0].extra1 = &net->ipv4.frags.low_thresh; 7691bab4c75SNikolay Aleksandrov table[0].extra2 = &init_net.ipv4.frags.high_thresh; 770e31e0bdcSPavel Emelyanov table[1].data = &net->ipv4.frags.low_thresh; 7711bab4c75SNikolay Aleksandrov table[1].extra2 = &net->ipv4.frags.high_thresh; 772b2fd5321SPavel Emelyanov table[2].data = &net->ipv4.frags.timeout; 773464dc801SEric W. Biederman 774464dc801SEric W. Biederman /* Don't export sysctls to unprivileged users */ 775464dc801SEric W. Biederman if (net->user_ns != &init_user_ns) 776464dc801SEric W. Biederman table[0].procname = NULL; 777e4a2d5c2SPavel Emelyanov } 778e4a2d5c2SPavel Emelyanov 779ec8f23ceSEric W. Biederman hdr = register_net_sysctl(net, "net/ipv4", table); 78051456b29SIan Morris if (!hdr) 781e4a2d5c2SPavel Emelyanov goto err_reg; 782e4a2d5c2SPavel Emelyanov 783e4a2d5c2SPavel Emelyanov net->ipv4.frags_hdr = hdr; 784e4a2d5c2SPavel Emelyanov return 0; 785e4a2d5c2SPavel Emelyanov 786e4a2d5c2SPavel Emelyanov err_reg: 78709ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) 788e4a2d5c2SPavel Emelyanov kfree(table); 789e4a2d5c2SPavel Emelyanov err_alloc: 790e4a2d5c2SPavel Emelyanov return -ENOMEM; 791e4a2d5c2SPavel Emelyanov } 792e4a2d5c2SPavel Emelyanov 7932c8c1e72SAlexey Dobriyan static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net) 794e4a2d5c2SPavel Emelyanov { 795e4a2d5c2SPavel Emelyanov struct ctl_table *table; 796e4a2d5c2SPavel Emelyanov 797e4a2d5c2SPavel Emelyanov table = net->ipv4.frags_hdr->ctl_table_arg; 798e4a2d5c2SPavel Emelyanov unregister_net_sysctl_table(net->ipv4.frags_hdr); 799e4a2d5c2SPavel Emelyanov kfree(table); 8008d8354d2SPavel Emelyanov } 8017d291ebbSPavel Emelyanov 80257a02c39SFabian Frederick static void __init ip4_frags_ctl_register(void) 8037d291ebbSPavel Emelyanov { 80443444757SEric W. Biederman register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table); 8057d291ebbSPavel Emelyanov } 8068d8354d2SPavel Emelyanov #else 807aa1f731eSFabian Frederick static int ip4_frags_ns_ctl_register(struct net *net) 8088d8354d2SPavel Emelyanov { 8098d8354d2SPavel Emelyanov return 0; 8108d8354d2SPavel Emelyanov } 811e4a2d5c2SPavel Emelyanov 812aa1f731eSFabian Frederick static void ip4_frags_ns_ctl_unregister(struct net *net) 813e4a2d5c2SPavel Emelyanov { 814e4a2d5c2SPavel Emelyanov } 8157d291ebbSPavel Emelyanov 816aa1f731eSFabian Frederick static void __init ip4_frags_ctl_register(void) 8177d291ebbSPavel Emelyanov { 8187d291ebbSPavel Emelyanov } 8198d8354d2SPavel Emelyanov #endif 8208d8354d2SPavel Emelyanov 8212c8c1e72SAlexey Dobriyan static int __net_init ipv4_frags_init_net(struct net *net) 8228d8354d2SPavel Emelyanov { 823c2a93660SJesper Dangaard Brouer /* Fragment cache limits. 824c2a93660SJesper Dangaard Brouer * 825c2a93660SJesper Dangaard Brouer * The fragment memory accounting code, (tries to) account for 826c2a93660SJesper Dangaard Brouer * the real memory usage, by measuring both the size of frag 827c2a93660SJesper Dangaard Brouer * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) 828c2a93660SJesper Dangaard Brouer * and the SKB's truesize. 829c2a93660SJesper Dangaard Brouer * 830c2a93660SJesper Dangaard Brouer * A 64K fragment consumes 129736 bytes (44*2944)+200 831c2a93660SJesper Dangaard Brouer * (1500 truesize == 2944, sizeof(struct ipq) == 200) 832c2a93660SJesper Dangaard Brouer * 833c2a93660SJesper Dangaard Brouer * We will commit 4MB at one time. Should we cross that limit 834c2a93660SJesper Dangaard Brouer * we will prune down to 3MB, making room for approx 8 big 64K 835c2a93660SJesper Dangaard Brouer * fragments 8x128k. 836e31e0bdcSPavel Emelyanov */ 837c2a93660SJesper Dangaard Brouer net->ipv4.frags.high_thresh = 4 * 1024 * 1024; 838c2a93660SJesper Dangaard Brouer net->ipv4.frags.low_thresh = 3 * 1024 * 1024; 839e31e0bdcSPavel Emelyanov /* 840b2fd5321SPavel Emelyanov * Important NOTE! Fragment queue must be destroyed before MSL expires. 841b2fd5321SPavel Emelyanov * RFC791 is wrong proposing to prolongate timer each fragment arrival 842b2fd5321SPavel Emelyanov * by TTL. 843b2fd5321SPavel Emelyanov */ 844b2fd5321SPavel Emelyanov net->ipv4.frags.timeout = IP_FRAG_TIME; 845b2fd5321SPavel Emelyanov 846e5a2bb84SPavel Emelyanov inet_frags_init_net(&net->ipv4.frags); 847e5a2bb84SPavel Emelyanov 8480a64b4b8SPavel Emelyanov return ip4_frags_ns_ctl_register(net); 8498d8354d2SPavel Emelyanov } 8508d8354d2SPavel Emelyanov 8512c8c1e72SAlexey Dobriyan static void __net_exit ipv4_frags_exit_net(struct net *net) 85281566e83SPavel Emelyanov { 8530a64b4b8SPavel Emelyanov ip4_frags_ns_ctl_unregister(net); 85481566e83SPavel Emelyanov inet_frags_exit_net(&net->ipv4.frags, &ip4_frags); 85581566e83SPavel Emelyanov } 85681566e83SPavel Emelyanov 85781566e83SPavel Emelyanov static struct pernet_operations ip4_frags_ops = { 85881566e83SPavel Emelyanov .init = ipv4_frags_init_net, 85981566e83SPavel Emelyanov .exit = ipv4_frags_exit_net, 86081566e83SPavel Emelyanov }; 86181566e83SPavel Emelyanov 862b7aa0bf7SEric Dumazet void __init ipfrag_init(void) 8631da177e4SLinus Torvalds { 8647d291ebbSPavel Emelyanov ip4_frags_ctl_register(); 86581566e83SPavel Emelyanov register_pernet_subsys(&ip4_frags_ops); 866321a3a99SPavel Emelyanov ip4_frags.hashfn = ip4_hashfn; 867c6fda282SPavel Emelyanov ip4_frags.constructor = ip4_frag_init; 8681e4b8287SPavel Emelyanov ip4_frags.destructor = ip4_frag_free; 8691e4b8287SPavel Emelyanov ip4_frags.skb_free = NULL; 8701e4b8287SPavel Emelyanov ip4_frags.qsize = sizeof(struct ipq); 871abd6523dSPavel Emelyanov ip4_frags.match = ip4_frag_match; 872e521db9dSPavel Emelyanov ip4_frags.frag_expire = ip_expire; 873d4ad4d22SNikolay Aleksandrov ip4_frags.frags_cache_name = ip_frag_cache_name; 874d4ad4d22SNikolay Aleksandrov if (inet_frags_init(&ip4_frags)) 875d4ad4d22SNikolay Aleksandrov panic("IP: failed to allocate ip4_frags cache\n"); 8761da177e4SLinus Torvalds } 877