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 1761da177e4SLinus Torvalds /* 1771da177e4SLinus Torvalds * Oops, a fragment queue timed out. Kill it and send an ICMP reply. 1781da177e4SLinus Torvalds */ 1791da177e4SLinus Torvalds static void ip_expire(unsigned long arg) 1801da177e4SLinus Torvalds { 181e521db9dSPavel Emelyanov struct ipq *qp; 18284a3aa00SPavel Emelyanov struct net *net; 183e521db9dSPavel Emelyanov 184e521db9dSPavel Emelyanov qp = container_of((struct inet_frag_queue *) arg, struct ipq, q); 18584a3aa00SPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 1861da177e4SLinus Torvalds 1875ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 1881da177e4SLinus Torvalds 18906aa8b8aSNikolay Aleksandrov if (qp->q.flags & INET_FRAG_COMPLETE) 1901da177e4SLinus Torvalds goto out; 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds ipq_kill(qp); 1937c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 1941da177e4SLinus Torvalds 1952e404f63SNikolay Aleksandrov if (!(qp->q.flags & INET_FRAG_EVICTED)) { 1965ab11c98SPavel Emelyanov struct sk_buff *head = qp->q.fragments; 19764f3b9e2SEric Dumazet const struct iphdr *iph; 19864f3b9e2SEric Dumazet int err; 199cb84663eSDenis V. Lunev 2002e404f63SNikolay Aleksandrov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMTIMEOUT); 2012e404f63SNikolay Aleksandrov 2022e404f63SNikolay Aleksandrov if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !qp->q.fragments) 2032e404f63SNikolay Aleksandrov goto out; 2042e404f63SNikolay Aleksandrov 20569df9d59SEric Dumazet rcu_read_lock(); 20669df9d59SEric Dumazet head->dev = dev_get_by_index_rcu(net, qp->iif); 207e9017b55SShan Wei if (!head->dev) 208e9017b55SShan Wei goto out_rcu_unlock; 209e9017b55SShan Wei 21097599dc7SEric Dumazet /* skb has no dst, perform route lookup again */ 21164f3b9e2SEric Dumazet iph = ip_hdr(head); 212c6cffba4SDavid S. Miller err = ip_route_input_noref(head, iph->daddr, iph->saddr, 213c10237e0SDavid S. Miller iph->tos, head->dev); 21464f3b9e2SEric Dumazet if (err) 215e9017b55SShan Wei goto out_rcu_unlock; 216e9017b55SShan Wei 2172e404f63SNikolay Aleksandrov /* Only an end host needs to send an ICMP 218e9017b55SShan Wei * "Fragment Reassembly Timeout" message, per RFC792. 219e9017b55SShan Wei */ 220595fc71bSDavid S. Miller if (qp->user == IP_DEFRAG_AF_PACKET || 2217c3d5ab1SVasily Averin ((qp->user >= IP_DEFRAG_CONNTRACK_IN) && 2227c3d5ab1SVasily Averin (qp->user <= __IP_DEFRAG_CONNTRACK_IN_END) && 2237c3d5ab1SVasily Averin (skb_rtable(head)->rt_type != RTN_LOCAL))) 224e9017b55SShan Wei goto out_rcu_unlock; 225e9017b55SShan Wei 226e9017b55SShan Wei /* Send an ICMP "Fragment Reassembly Timeout" message. */ 227e9017b55SShan Wei icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); 228e9017b55SShan Wei out_rcu_unlock: 229e9017b55SShan Wei rcu_read_unlock(); 230d1c9ae6dSPatrick McHardy } 2311da177e4SLinus Torvalds out: 2325ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 2334b6cb5d8SPavel Emelyanov ipq_put(qp); 2341da177e4SLinus Torvalds } 2351da177e4SLinus Torvalds 236abd6523dSPavel Emelyanov /* Find the correct entry in the "incomplete datagrams" queue for 237abd6523dSPavel Emelyanov * this IP datagram, and create new one, if nothing is found. 238abd6523dSPavel Emelyanov */ 239aa1f731eSFabian Frederick static struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user) 2401da177e4SLinus Torvalds { 241c6fda282SPavel Emelyanov struct inet_frag_queue *q; 242c6fda282SPavel Emelyanov struct ip4_create_arg arg; 243abd6523dSPavel Emelyanov unsigned int hash; 2441da177e4SLinus Torvalds 245c6fda282SPavel Emelyanov arg.iph = iph; 246c6fda282SPavel Emelyanov arg.user = user; 2479a375803SPavel Emelyanov 248abd6523dSPavel Emelyanov hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol); 249c6fda282SPavel Emelyanov 250ac18e750SPavel Emelyanov q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash); 2515a3da1feSHannes Frederic Sowa if (IS_ERR_OR_NULL(q)) { 2525a3da1feSHannes Frederic Sowa inet_frag_maybe_warn_overflow(q, pr_fmt()); 2531da177e4SLinus Torvalds return NULL; 2541da177e4SLinus Torvalds } 2555a3da1feSHannes Frederic Sowa return container_of(q, struct ipq, q); 2565a3da1feSHannes Frederic Sowa } 2571da177e4SLinus Torvalds 25889cee8b1SHerbert Xu /* Is the fragment too far ahead to be part of ipq? */ 259aa1f731eSFabian Frederick static int ip_frag_too_far(struct ipq *qp) 26089cee8b1SHerbert Xu { 26189cee8b1SHerbert Xu struct inet_peer *peer = qp->peer; 26289cee8b1SHerbert Xu unsigned int max = sysctl_ipfrag_max_dist; 26389cee8b1SHerbert Xu unsigned int start, end; 26489cee8b1SHerbert Xu 26589cee8b1SHerbert Xu int rc; 26689cee8b1SHerbert Xu 26789cee8b1SHerbert Xu if (!peer || !max) 26889cee8b1SHerbert Xu return 0; 26989cee8b1SHerbert Xu 27089cee8b1SHerbert Xu start = qp->rid; 27189cee8b1SHerbert Xu end = atomic_inc_return(&peer->rid); 27289cee8b1SHerbert Xu qp->rid = end; 27389cee8b1SHerbert Xu 2745ab11c98SPavel Emelyanov rc = qp->q.fragments && (end - start) > max; 27589cee8b1SHerbert Xu 27689cee8b1SHerbert Xu if (rc) { 2777c73a6faSPavel Emelyanov struct net *net; 2787c73a6faSPavel Emelyanov 2797c73a6faSPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 2807c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 28189cee8b1SHerbert Xu } 28289cee8b1SHerbert Xu 28389cee8b1SHerbert Xu return rc; 28489cee8b1SHerbert Xu } 28589cee8b1SHerbert Xu 28689cee8b1SHerbert Xu static int ip_frag_reinit(struct ipq *qp) 28789cee8b1SHerbert Xu { 28889cee8b1SHerbert Xu struct sk_buff *fp; 289d433673eSJesper Dangaard Brouer unsigned int sum_truesize = 0; 29089cee8b1SHerbert Xu 291b2fd5321SPavel Emelyanov if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) { 2925ab11c98SPavel Emelyanov atomic_inc(&qp->q.refcnt); 29389cee8b1SHerbert Xu return -ETIMEDOUT; 29489cee8b1SHerbert Xu } 29589cee8b1SHerbert Xu 2965ab11c98SPavel Emelyanov fp = qp->q.fragments; 29789cee8b1SHerbert Xu do { 29889cee8b1SHerbert Xu struct sk_buff *xp = fp->next; 299d433673eSJesper Dangaard Brouer 300d433673eSJesper Dangaard Brouer sum_truesize += fp->truesize; 301d433673eSJesper Dangaard Brouer kfree_skb(fp); 30289cee8b1SHerbert Xu fp = xp; 30389cee8b1SHerbert Xu } while (fp); 304d433673eSJesper Dangaard Brouer sub_frag_mem_limit(&qp->q, sum_truesize); 30589cee8b1SHerbert Xu 30606aa8b8aSNikolay Aleksandrov qp->q.flags = 0; 3075ab11c98SPavel Emelyanov qp->q.len = 0; 3085ab11c98SPavel Emelyanov qp->q.meat = 0; 3095ab11c98SPavel Emelyanov qp->q.fragments = NULL; 310d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 31189cee8b1SHerbert Xu qp->iif = 0; 3126623e3b2SEric Dumazet qp->ecn = 0; 31389cee8b1SHerbert Xu 31489cee8b1SHerbert Xu return 0; 31589cee8b1SHerbert Xu } 31689cee8b1SHerbert Xu 3171da177e4SLinus Torvalds /* Add new segment to existing queue. */ 3181706d587SHerbert Xu static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) 3191da177e4SLinus Torvalds { 3201da177e4SLinus Torvalds struct sk_buff *prev, *next; 3211706d587SHerbert Xu struct net_device *dev; 3221da177e4SLinus Torvalds int flags, offset; 3231da177e4SLinus Torvalds int ihl, end; 3241706d587SHerbert Xu int err = -ENOENT; 3256623e3b2SEric Dumazet u8 ecn; 3261da177e4SLinus Torvalds 32706aa8b8aSNikolay Aleksandrov if (qp->q.flags & INET_FRAG_COMPLETE) 3281da177e4SLinus Torvalds goto err; 3291da177e4SLinus Torvalds 33089cee8b1SHerbert Xu if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && 3311706d587SHerbert Xu unlikely(ip_frag_too_far(qp)) && 3321706d587SHerbert Xu unlikely(err = ip_frag_reinit(qp))) { 33389cee8b1SHerbert Xu ipq_kill(qp); 33489cee8b1SHerbert Xu goto err; 33589cee8b1SHerbert Xu } 33689cee8b1SHerbert Xu 3376623e3b2SEric Dumazet ecn = ip4_frag_ecn(ip_hdr(skb)->tos); 338eddc9ec5SArnaldo Carvalho de Melo offset = ntohs(ip_hdr(skb)->frag_off); 3391da177e4SLinus Torvalds flags = offset & ~IP_OFFSET; 3401da177e4SLinus Torvalds offset &= IP_OFFSET; 3411da177e4SLinus Torvalds offset <<= 3; /* offset is in 8-byte chunks */ 342c9bdd4b5SArnaldo Carvalho de Melo ihl = ip_hdrlen(skb); 3431da177e4SLinus Torvalds 3441da177e4SLinus Torvalds /* Determine the position of this fragment. */ 3451da177e4SLinus Torvalds end = offset + skb->len - ihl; 3461706d587SHerbert Xu err = -EINVAL; 3471da177e4SLinus Torvalds 3481da177e4SLinus Torvalds /* Is this the final fragment? */ 3491da177e4SLinus Torvalds if ((flags & IP_MF) == 0) { 3501da177e4SLinus Torvalds /* If we already have some bits beyond end 35142b2aa86SJustin P. Mattock * or have different end, the segment is corrupted. 3521da177e4SLinus Torvalds */ 3535ab11c98SPavel Emelyanov if (end < qp->q.len || 35406aa8b8aSNikolay Aleksandrov ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len)) 3551da177e4SLinus Torvalds goto err; 35606aa8b8aSNikolay Aleksandrov qp->q.flags |= INET_FRAG_LAST_IN; 3575ab11c98SPavel Emelyanov qp->q.len = end; 3581da177e4SLinus Torvalds } else { 3591da177e4SLinus Torvalds if (end&7) { 3601da177e4SLinus Torvalds end &= ~7; 3611da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 3621da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 3631da177e4SLinus Torvalds } 3645ab11c98SPavel Emelyanov if (end > qp->q.len) { 3651da177e4SLinus Torvalds /* Some bits beyond end -> corruption. */ 36606aa8b8aSNikolay Aleksandrov if (qp->q.flags & INET_FRAG_LAST_IN) 3671da177e4SLinus Torvalds goto err; 3685ab11c98SPavel Emelyanov qp->q.len = end; 3691da177e4SLinus Torvalds } 3701da177e4SLinus Torvalds } 3711da177e4SLinus Torvalds if (end == offset) 3721da177e4SLinus Torvalds goto err; 3731da177e4SLinus Torvalds 3741706d587SHerbert Xu err = -ENOMEM; 37551456b29SIan Morris if (!pskb_pull(skb, ihl)) 3761da177e4SLinus Torvalds goto err; 3771706d587SHerbert Xu 3781706d587SHerbert Xu err = pskb_trim_rcsum(skb, end - offset); 3791706d587SHerbert Xu if (err) 3801da177e4SLinus Torvalds goto err; 3811da177e4SLinus Torvalds 3821da177e4SLinus Torvalds /* Find out which fragments are in front and at the back of us 3831da177e4SLinus Torvalds * in the chain of fragments so far. We must know where to put 3841da177e4SLinus Torvalds * this fragment, right? 3851da177e4SLinus Torvalds */ 386d6bebca9SChangli Gao prev = qp->q.fragments_tail; 387d6bebca9SChangli Gao if (!prev || FRAG_CB(prev)->offset < offset) { 388d6bebca9SChangli Gao next = NULL; 389d6bebca9SChangli Gao goto found; 390d6bebca9SChangli Gao } 3911da177e4SLinus Torvalds prev = NULL; 3925ab11c98SPavel Emelyanov for (next = qp->q.fragments; next != NULL; next = next->next) { 3931da177e4SLinus Torvalds if (FRAG_CB(next)->offset >= offset) 3941da177e4SLinus Torvalds break; /* bingo! */ 3951da177e4SLinus Torvalds prev = next; 3961da177e4SLinus Torvalds } 3971da177e4SLinus Torvalds 398d6bebca9SChangli Gao found: 3991da177e4SLinus Torvalds /* We found where to put this one. Check for overlap with 4001da177e4SLinus Torvalds * preceding fragment, and, if needed, align things so that 4011da177e4SLinus Torvalds * any overlaps are eliminated. 4021da177e4SLinus Torvalds */ 4031da177e4SLinus Torvalds if (prev) { 4041da177e4SLinus Torvalds int i = (FRAG_CB(prev)->offset + prev->len) - offset; 4051da177e4SLinus Torvalds 4061da177e4SLinus Torvalds if (i > 0) { 4071da177e4SLinus Torvalds offset += i; 4081706d587SHerbert Xu err = -EINVAL; 4091da177e4SLinus Torvalds if (end <= offset) 4101da177e4SLinus Torvalds goto err; 4111706d587SHerbert Xu err = -ENOMEM; 4121da177e4SLinus Torvalds if (!pskb_pull(skb, i)) 4131da177e4SLinus Torvalds goto err; 4141da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 4151da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 4161da177e4SLinus Torvalds } 4171da177e4SLinus Torvalds } 4181da177e4SLinus Torvalds 4191706d587SHerbert Xu err = -ENOMEM; 4201706d587SHerbert Xu 4211da177e4SLinus Torvalds while (next && FRAG_CB(next)->offset < end) { 4221da177e4SLinus Torvalds int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */ 4231da177e4SLinus Torvalds 4241da177e4SLinus Torvalds if (i < next->len) { 4251da177e4SLinus Torvalds /* Eat head of the next overlapped fragment 4261da177e4SLinus Torvalds * and leave the loop. The next ones cannot overlap. 4271da177e4SLinus Torvalds */ 4281da177e4SLinus Torvalds if (!pskb_pull(next, i)) 4291da177e4SLinus Torvalds goto err; 4301da177e4SLinus Torvalds FRAG_CB(next)->offset += i; 4315ab11c98SPavel Emelyanov qp->q.meat -= i; 4321da177e4SLinus Torvalds if (next->ip_summed != CHECKSUM_UNNECESSARY) 4331da177e4SLinus Torvalds next->ip_summed = CHECKSUM_NONE; 4341da177e4SLinus Torvalds break; 4351da177e4SLinus Torvalds } else { 4361da177e4SLinus Torvalds struct sk_buff *free_it = next; 4371da177e4SLinus Torvalds 43847c6bf77SPeter Zijlstra /* Old fragment is completely overridden with 4391da177e4SLinus Torvalds * new one drop it. 4401da177e4SLinus Torvalds */ 4411da177e4SLinus Torvalds next = next->next; 4421da177e4SLinus Torvalds 4431da177e4SLinus Torvalds if (prev) 4441da177e4SLinus Torvalds prev->next = next; 4451da177e4SLinus Torvalds else 4465ab11c98SPavel Emelyanov qp->q.fragments = next; 4471da177e4SLinus Torvalds 4485ab11c98SPavel Emelyanov qp->q.meat -= free_it->len; 449d433673eSJesper Dangaard Brouer sub_frag_mem_limit(&qp->q, free_it->truesize); 450d433673eSJesper Dangaard Brouer kfree_skb(free_it); 4511da177e4SLinus Torvalds } 4521da177e4SLinus Torvalds } 4531da177e4SLinus Torvalds 4541da177e4SLinus Torvalds FRAG_CB(skb)->offset = offset; 4551da177e4SLinus Torvalds 4561da177e4SLinus Torvalds /* Insert this fragment in the chain of fragments. */ 4571da177e4SLinus Torvalds skb->next = next; 458d6bebca9SChangli Gao if (!next) 459d6bebca9SChangli Gao qp->q.fragments_tail = skb; 4601da177e4SLinus Torvalds if (prev) 4611da177e4SLinus Torvalds prev->next = skb; 4621da177e4SLinus Torvalds else 4635ab11c98SPavel Emelyanov qp->q.fragments = skb; 4641da177e4SLinus Torvalds 4651706d587SHerbert Xu dev = skb->dev; 4661706d587SHerbert Xu if (dev) { 4671706d587SHerbert Xu qp->iif = dev->ifindex; 4681da177e4SLinus Torvalds skb->dev = NULL; 4691706d587SHerbert Xu } 4705ab11c98SPavel Emelyanov qp->q.stamp = skb->tstamp; 4715ab11c98SPavel Emelyanov qp->q.meat += skb->len; 4726623e3b2SEric Dumazet qp->ecn |= ecn; 473d433673eSJesper Dangaard Brouer add_frag_mem_limit(&qp->q, skb->truesize); 4741da177e4SLinus Torvalds if (offset == 0) 47506aa8b8aSNikolay Aleksandrov qp->q.flags |= INET_FRAG_FIRST_IN; 4761da177e4SLinus Torvalds 4775f2d04f1SPatrick McHardy if (ip_hdr(skb)->frag_off & htons(IP_DF) && 4785f2d04f1SPatrick McHardy skb->len + ihl > qp->q.max_size) 4795f2d04f1SPatrick McHardy qp->q.max_size = skb->len + ihl; 4805f2d04f1SPatrick McHardy 48106aa8b8aSNikolay Aleksandrov if (qp->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && 48297599dc7SEric Dumazet qp->q.meat == qp->q.len) { 48397599dc7SEric Dumazet unsigned long orefdst = skb->_skb_refdst; 4841706d587SHerbert Xu 48597599dc7SEric Dumazet skb->_skb_refdst = 0UL; 48697599dc7SEric Dumazet err = ip_frag_reasm(qp, prev, dev); 48797599dc7SEric Dumazet skb->_skb_refdst = orefdst; 48897599dc7SEric Dumazet return err; 48997599dc7SEric Dumazet } 49097599dc7SEric Dumazet 49197599dc7SEric Dumazet skb_dst_drop(skb); 4921706d587SHerbert Xu return -EINPROGRESS; 4931da177e4SLinus Torvalds 4941da177e4SLinus Torvalds err: 4951da177e4SLinus Torvalds kfree_skb(skb); 4961706d587SHerbert Xu return err; 4971da177e4SLinus Torvalds } 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds 5001da177e4SLinus Torvalds /* Build a new IP datagram from all its fragments. */ 5011da177e4SLinus Torvalds 5021706d587SHerbert Xu static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 5031706d587SHerbert Xu struct net_device *dev) 5041da177e4SLinus Torvalds { 5052bad35b7SJorge Boncompte [DTI2] struct net *net = container_of(qp->q.net, struct net, ipv4.frags); 5061da177e4SLinus Torvalds struct iphdr *iph; 5075ab11c98SPavel Emelyanov struct sk_buff *fp, *head = qp->q.fragments; 5081da177e4SLinus Torvalds int len; 5091da177e4SLinus Torvalds int ihlen; 5101706d587SHerbert Xu int err; 5113cc49492SEric Dumazet int sum_truesize; 5125173cc05SEric Dumazet u8 ecn; 5131da177e4SLinus Torvalds 5141da177e4SLinus Torvalds ipq_kill(qp); 5151da177e4SLinus Torvalds 516be991971SHannes Frederic Sowa ecn = ip_frag_ecn_table[qp->ecn]; 5175173cc05SEric Dumazet if (unlikely(ecn == 0xff)) { 5185173cc05SEric Dumazet err = -EINVAL; 5195173cc05SEric Dumazet goto out_fail; 5205173cc05SEric Dumazet } 5211706d587SHerbert Xu /* Make the one we just received the head. */ 5221706d587SHerbert Xu if (prev) { 5231706d587SHerbert Xu head = prev->next; 5241706d587SHerbert Xu fp = skb_clone(head, GFP_ATOMIC); 5251706d587SHerbert Xu if (!fp) 5261706d587SHerbert Xu goto out_nomem; 5271706d587SHerbert Xu 5281706d587SHerbert Xu fp->next = head->next; 529d6bebca9SChangli Gao if (!fp->next) 530d6bebca9SChangli Gao qp->q.fragments_tail = fp; 5311706d587SHerbert Xu prev->next = fp; 5321706d587SHerbert Xu 5335ab11c98SPavel Emelyanov skb_morph(head, qp->q.fragments); 5345ab11c98SPavel Emelyanov head->next = qp->q.fragments->next; 5351706d587SHerbert Xu 536cbf8f7bbSEric Dumazet consume_skb(qp->q.fragments); 5375ab11c98SPavel Emelyanov qp->q.fragments = head; 5381706d587SHerbert Xu } 5391706d587SHerbert Xu 54051456b29SIan Morris WARN_ON(!head); 541547b792cSIlpo Järvinen WARN_ON(FRAG_CB(head)->offset != 0); 5421da177e4SLinus Torvalds 5431da177e4SLinus Torvalds /* Allocate a new buffer for the datagram. */ 544c9bdd4b5SArnaldo Carvalho de Melo ihlen = ip_hdrlen(head); 5455ab11c98SPavel Emelyanov len = ihlen + qp->q.len; 5461da177e4SLinus Torvalds 5471706d587SHerbert Xu err = -E2BIG; 5481da177e4SLinus Torvalds if (len > 65535) 5491da177e4SLinus Torvalds goto out_oversize; 5501da177e4SLinus Torvalds 5511da177e4SLinus Torvalds /* Head of list must not be cloned. */ 55214bbd6a5SPravin B Shelar if (skb_unclone(head, GFP_ATOMIC)) 5531da177e4SLinus Torvalds goto out_nomem; 5541da177e4SLinus Torvalds 5551da177e4SLinus Torvalds /* If the first fragment is fragmented itself, we split 5561da177e4SLinus Torvalds * it to two chunks: the first with data and paged part 5571da177e4SLinus Torvalds * and the second, holding only fragments. */ 55821dc3301SDavid S. Miller if (skb_has_frag_list(head)) { 5591da177e4SLinus Torvalds struct sk_buff *clone; 5601da177e4SLinus Torvalds int i, plen = 0; 5611da177e4SLinus Torvalds 56251456b29SIan Morris clone = alloc_skb(0, GFP_ATOMIC); 56351456b29SIan Morris if (!clone) 5641da177e4SLinus Torvalds goto out_nomem; 5651da177e4SLinus Torvalds clone->next = head->next; 5661da177e4SLinus Torvalds head->next = clone; 5671da177e4SLinus Torvalds skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 568d7fcf1a5SDavid S. Miller skb_frag_list_init(head); 5691da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(head)->nr_frags; i++) 5709e903e08SEric Dumazet plen += skb_frag_size(&skb_shinfo(head)->frags[i]); 5711da177e4SLinus Torvalds clone->len = clone->data_len = head->data_len - plen; 5721da177e4SLinus Torvalds head->data_len -= clone->len; 5731da177e4SLinus Torvalds head->len -= clone->len; 5741da177e4SLinus Torvalds clone->csum = 0; 5751da177e4SLinus Torvalds clone->ip_summed = head->ip_summed; 576d433673eSJesper Dangaard Brouer add_frag_mem_limit(&qp->q, clone->truesize); 5771da177e4SLinus Torvalds } 5781da177e4SLinus Torvalds 579d56f90a7SArnaldo Carvalho de Melo skb_push(head, head->data - skb_network_header(head)); 5801da177e4SLinus Torvalds 5813cc49492SEric Dumazet sum_truesize = head->truesize; 5823cc49492SEric Dumazet for (fp = head->next; fp;) { 5833cc49492SEric Dumazet bool headstolen; 5843cc49492SEric Dumazet int delta; 5853cc49492SEric Dumazet struct sk_buff *next = fp->next; 5863cc49492SEric Dumazet 5873cc49492SEric Dumazet sum_truesize += fp->truesize; 5881da177e4SLinus Torvalds if (head->ip_summed != fp->ip_summed) 5891da177e4SLinus Torvalds head->ip_summed = CHECKSUM_NONE; 59084fa7933SPatrick McHardy else if (head->ip_summed == CHECKSUM_COMPLETE) 5911da177e4SLinus Torvalds head->csum = csum_add(head->csum, fp->csum); 5923cc49492SEric Dumazet 5933cc49492SEric Dumazet if (skb_try_coalesce(head, fp, &headstolen, &delta)) { 5943cc49492SEric Dumazet kfree_skb_partial(fp, headstolen); 5953cc49492SEric Dumazet } else { 5963cc49492SEric Dumazet if (!skb_shinfo(head)->frag_list) 5973cc49492SEric Dumazet skb_shinfo(head)->frag_list = fp; 5983cc49492SEric Dumazet head->data_len += fp->len; 5993cc49492SEric Dumazet head->len += fp->len; 6001da177e4SLinus Torvalds head->truesize += fp->truesize; 6011da177e4SLinus Torvalds } 6023cc49492SEric Dumazet fp = next; 6033cc49492SEric Dumazet } 604d433673eSJesper Dangaard Brouer sub_frag_mem_limit(&qp->q, sum_truesize); 6051da177e4SLinus Torvalds 6061da177e4SLinus Torvalds head->next = NULL; 6071da177e4SLinus Torvalds head->dev = dev; 6085ab11c98SPavel Emelyanov head->tstamp = qp->q.stamp; 6095f2d04f1SPatrick McHardy IPCB(head)->frag_max_size = qp->q.max_size; 6101da177e4SLinus Torvalds 611eddc9ec5SArnaldo Carvalho de Melo iph = ip_hdr(head); 6125f2d04f1SPatrick McHardy /* max_size != 0 implies at least one fragment had IP_DF set */ 6135f2d04f1SPatrick McHardy iph->frag_off = qp->q.max_size ? htons(IP_DF) : 0; 6141da177e4SLinus Torvalds iph->tot_len = htons(len); 6155173cc05SEric Dumazet iph->tos |= ecn; 6162bad35b7SJorge Boncompte [DTI2] IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS); 6175ab11c98SPavel Emelyanov qp->q.fragments = NULL; 618d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 6191706d587SHerbert Xu return 0; 6201da177e4SLinus Torvalds 6211da177e4SLinus Torvalds out_nomem: 622ba7a46f1SJoe Perches net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp); 62345542479SDavid Howells err = -ENOMEM; 6241da177e4SLinus Torvalds goto out_fail; 6251da177e4SLinus Torvalds out_oversize: 626e87cc472SJoe Perches net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->saddr); 6271da177e4SLinus Torvalds out_fail: 628bbf31bf1SDavid Ford IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 6291706d587SHerbert Xu return err; 6301da177e4SLinus Torvalds } 6311da177e4SLinus Torvalds 6321da177e4SLinus Torvalds /* Process an incoming IP datagram fragment. */ 633776c729eSHerbert Xu int ip_defrag(struct sk_buff *skb, u32 user) 6341da177e4SLinus Torvalds { 6351da177e4SLinus Torvalds struct ipq *qp; 636ac18e750SPavel Emelyanov struct net *net; 6371da177e4SLinus Torvalds 638adf30907SEric Dumazet net = skb->dev ? dev_net(skb->dev) : dev_net(skb_dst(skb)->dev); 6397c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMREQDS); 6401da177e4SLinus Torvalds 6411da177e4SLinus Torvalds /* Lookup (or create) queue header */ 642*00db4124SIan Morris qp = ip_find(net, ip_hdr(skb), user); 643*00db4124SIan Morris if (qp) { 6441706d587SHerbert Xu int ret; 6451da177e4SLinus Torvalds 6465ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 6471da177e4SLinus Torvalds 6481706d587SHerbert Xu ret = ip_frag_queue(qp, skb); 6491da177e4SLinus Torvalds 6505ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 6514b6cb5d8SPavel Emelyanov ipq_put(qp); 652776c729eSHerbert Xu return ret; 6531da177e4SLinus Torvalds } 6541da177e4SLinus Torvalds 6557c73a6faSPavel Emelyanov IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS); 6561da177e4SLinus Torvalds kfree_skb(skb); 657776c729eSHerbert Xu return -ENOMEM; 6581da177e4SLinus Torvalds } 6594bc2f18bSEric Dumazet EXPORT_SYMBOL(ip_defrag); 6601da177e4SLinus Torvalds 661bc416d97SEric Dumazet struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) 662bc416d97SEric Dumazet { 6631bf3751eSJohannes Berg struct iphdr iph; 6643e32e733SAlexander Drozdov int netoff; 665bc416d97SEric Dumazet u32 len; 666bc416d97SEric Dumazet 667bc416d97SEric Dumazet if (skb->protocol != htons(ETH_P_IP)) 668bc416d97SEric Dumazet return skb; 669bc416d97SEric Dumazet 6703e32e733SAlexander Drozdov netoff = skb_network_offset(skb); 6713e32e733SAlexander Drozdov 6723e32e733SAlexander Drozdov if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0) 673bc416d97SEric Dumazet return skb; 674bc416d97SEric Dumazet 6751bf3751eSJohannes Berg if (iph.ihl < 5 || iph.version != 4) 676bc416d97SEric Dumazet return skb; 677bc416d97SEric Dumazet 6781bf3751eSJohannes Berg len = ntohs(iph.tot_len); 6793e32e733SAlexander Drozdov if (skb->len < netoff + len || len < (iph.ihl * 4)) 6801bf3751eSJohannes Berg return skb; 6811bf3751eSJohannes Berg 6821bf3751eSJohannes Berg if (ip_is_fragment(&iph)) { 683bc416d97SEric Dumazet skb = skb_share_check(skb, GFP_ATOMIC); 684bc416d97SEric Dumazet if (skb) { 6853e32e733SAlexander Drozdov if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) 6861bf3751eSJohannes Berg return skb; 6873e32e733SAlexander Drozdov if (pskb_trim_rcsum(skb, netoff + len)) 688bc416d97SEric Dumazet return skb; 689bc416d97SEric Dumazet memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 690bc416d97SEric Dumazet if (ip_defrag(skb, user)) 691bc416d97SEric Dumazet return NULL; 6927539fadcSTom Herbert skb_clear_hash(skb); 693bc416d97SEric Dumazet } 694bc416d97SEric Dumazet } 695bc416d97SEric Dumazet return skb; 696bc416d97SEric Dumazet } 697bc416d97SEric Dumazet EXPORT_SYMBOL(ip_check_defrag); 698bc416d97SEric Dumazet 6998d8354d2SPavel Emelyanov #ifdef CONFIG_SYSCTL 7008d8354d2SPavel Emelyanov static int zero; 7018d8354d2SPavel Emelyanov 7020a64b4b8SPavel Emelyanov static struct ctl_table ip4_frags_ns_ctl_table[] = { 7038d8354d2SPavel Emelyanov { 7048d8354d2SPavel Emelyanov .procname = "ipfrag_high_thresh", 705e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.high_thresh, 7068d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7078d8354d2SPavel Emelyanov .mode = 0644, 7081bab4c75SNikolay Aleksandrov .proc_handler = proc_dointvec_minmax, 7091bab4c75SNikolay Aleksandrov .extra1 = &init_net.ipv4.frags.low_thresh 7108d8354d2SPavel Emelyanov }, 7118d8354d2SPavel Emelyanov { 7128d8354d2SPavel Emelyanov .procname = "ipfrag_low_thresh", 713e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.low_thresh, 7148d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7158d8354d2SPavel Emelyanov .mode = 0644, 7161bab4c75SNikolay Aleksandrov .proc_handler = proc_dointvec_minmax, 7171bab4c75SNikolay Aleksandrov .extra1 = &zero, 7181bab4c75SNikolay Aleksandrov .extra2 = &init_net.ipv4.frags.high_thresh 7198d8354d2SPavel Emelyanov }, 7208d8354d2SPavel Emelyanov { 7218d8354d2SPavel Emelyanov .procname = "ipfrag_time", 722b2fd5321SPavel Emelyanov .data = &init_net.ipv4.frags.timeout, 7238d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7248d8354d2SPavel Emelyanov .mode = 0644, 7256d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7268d8354d2SPavel Emelyanov }, 7277d291ebbSPavel Emelyanov { } 7287d291ebbSPavel Emelyanov }; 7297d291ebbSPavel Emelyanov 730e3a57d18SFlorian Westphal /* secret interval has been deprecated */ 731e3a57d18SFlorian Westphal static int ip4_frags_secret_interval_unused; 7327d291ebbSPavel Emelyanov static struct ctl_table ip4_frags_ctl_table[] = { 7338d8354d2SPavel Emelyanov { 7348d8354d2SPavel Emelyanov .procname = "ipfrag_secret_interval", 735e3a57d18SFlorian Westphal .data = &ip4_frags_secret_interval_unused, 7368d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7378d8354d2SPavel Emelyanov .mode = 0644, 7386d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7398d8354d2SPavel Emelyanov }, 7408d8354d2SPavel Emelyanov { 7418d8354d2SPavel Emelyanov .procname = "ipfrag_max_dist", 7428d8354d2SPavel Emelyanov .data = &sysctl_ipfrag_max_dist, 7438d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7448d8354d2SPavel Emelyanov .mode = 0644, 7456d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_minmax, 7468d8354d2SPavel Emelyanov .extra1 = &zero 7478d8354d2SPavel Emelyanov }, 7488d8354d2SPavel Emelyanov { } 7498d8354d2SPavel Emelyanov }; 7508d8354d2SPavel Emelyanov 7512c8c1e72SAlexey Dobriyan static int __net_init ip4_frags_ns_ctl_register(struct net *net) 7528d8354d2SPavel Emelyanov { 753e4a2d5c2SPavel Emelyanov struct ctl_table *table; 7548d8354d2SPavel Emelyanov struct ctl_table_header *hdr; 7558d8354d2SPavel Emelyanov 7560a64b4b8SPavel Emelyanov table = ip4_frags_ns_ctl_table; 75709ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) { 7580a64b4b8SPavel Emelyanov table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL); 75951456b29SIan Morris if (!table) 760e4a2d5c2SPavel Emelyanov goto err_alloc; 761e4a2d5c2SPavel Emelyanov 762e31e0bdcSPavel Emelyanov table[0].data = &net->ipv4.frags.high_thresh; 7631bab4c75SNikolay Aleksandrov table[0].extra1 = &net->ipv4.frags.low_thresh; 7641bab4c75SNikolay Aleksandrov table[0].extra2 = &init_net.ipv4.frags.high_thresh; 765e31e0bdcSPavel Emelyanov table[1].data = &net->ipv4.frags.low_thresh; 7661bab4c75SNikolay Aleksandrov table[1].extra2 = &net->ipv4.frags.high_thresh; 767b2fd5321SPavel Emelyanov table[2].data = &net->ipv4.frags.timeout; 768464dc801SEric W. Biederman 769464dc801SEric W. Biederman /* Don't export sysctls to unprivileged users */ 770464dc801SEric W. Biederman if (net->user_ns != &init_user_ns) 771464dc801SEric W. Biederman table[0].procname = NULL; 772e4a2d5c2SPavel Emelyanov } 773e4a2d5c2SPavel Emelyanov 774ec8f23ceSEric W. Biederman hdr = register_net_sysctl(net, "net/ipv4", table); 77551456b29SIan Morris if (!hdr) 776e4a2d5c2SPavel Emelyanov goto err_reg; 777e4a2d5c2SPavel Emelyanov 778e4a2d5c2SPavel Emelyanov net->ipv4.frags_hdr = hdr; 779e4a2d5c2SPavel Emelyanov return 0; 780e4a2d5c2SPavel Emelyanov 781e4a2d5c2SPavel Emelyanov err_reg: 78209ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) 783e4a2d5c2SPavel Emelyanov kfree(table); 784e4a2d5c2SPavel Emelyanov err_alloc: 785e4a2d5c2SPavel Emelyanov return -ENOMEM; 786e4a2d5c2SPavel Emelyanov } 787e4a2d5c2SPavel Emelyanov 7882c8c1e72SAlexey Dobriyan static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net) 789e4a2d5c2SPavel Emelyanov { 790e4a2d5c2SPavel Emelyanov struct ctl_table *table; 791e4a2d5c2SPavel Emelyanov 792e4a2d5c2SPavel Emelyanov table = net->ipv4.frags_hdr->ctl_table_arg; 793e4a2d5c2SPavel Emelyanov unregister_net_sysctl_table(net->ipv4.frags_hdr); 794e4a2d5c2SPavel Emelyanov kfree(table); 7958d8354d2SPavel Emelyanov } 7967d291ebbSPavel Emelyanov 79757a02c39SFabian Frederick static void __init ip4_frags_ctl_register(void) 7987d291ebbSPavel Emelyanov { 79943444757SEric W. Biederman register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table); 8007d291ebbSPavel Emelyanov } 8018d8354d2SPavel Emelyanov #else 802aa1f731eSFabian Frederick static int ip4_frags_ns_ctl_register(struct net *net) 8038d8354d2SPavel Emelyanov { 8048d8354d2SPavel Emelyanov return 0; 8058d8354d2SPavel Emelyanov } 806e4a2d5c2SPavel Emelyanov 807aa1f731eSFabian Frederick static void ip4_frags_ns_ctl_unregister(struct net *net) 808e4a2d5c2SPavel Emelyanov { 809e4a2d5c2SPavel Emelyanov } 8107d291ebbSPavel Emelyanov 811aa1f731eSFabian Frederick static void __init ip4_frags_ctl_register(void) 8127d291ebbSPavel Emelyanov { 8137d291ebbSPavel Emelyanov } 8148d8354d2SPavel Emelyanov #endif 8158d8354d2SPavel Emelyanov 8162c8c1e72SAlexey Dobriyan static int __net_init ipv4_frags_init_net(struct net *net) 8178d8354d2SPavel Emelyanov { 818c2a93660SJesper Dangaard Brouer /* Fragment cache limits. 819c2a93660SJesper Dangaard Brouer * 820c2a93660SJesper Dangaard Brouer * The fragment memory accounting code, (tries to) account for 821c2a93660SJesper Dangaard Brouer * the real memory usage, by measuring both the size of frag 822c2a93660SJesper Dangaard Brouer * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) 823c2a93660SJesper Dangaard Brouer * and the SKB's truesize. 824c2a93660SJesper Dangaard Brouer * 825c2a93660SJesper Dangaard Brouer * A 64K fragment consumes 129736 bytes (44*2944)+200 826c2a93660SJesper Dangaard Brouer * (1500 truesize == 2944, sizeof(struct ipq) == 200) 827c2a93660SJesper Dangaard Brouer * 828c2a93660SJesper Dangaard Brouer * We will commit 4MB at one time. Should we cross that limit 829c2a93660SJesper Dangaard Brouer * we will prune down to 3MB, making room for approx 8 big 64K 830c2a93660SJesper Dangaard Brouer * fragments 8x128k. 831e31e0bdcSPavel Emelyanov */ 832c2a93660SJesper Dangaard Brouer net->ipv4.frags.high_thresh = 4 * 1024 * 1024; 833c2a93660SJesper Dangaard Brouer net->ipv4.frags.low_thresh = 3 * 1024 * 1024; 834e31e0bdcSPavel Emelyanov /* 835b2fd5321SPavel Emelyanov * Important NOTE! Fragment queue must be destroyed before MSL expires. 836b2fd5321SPavel Emelyanov * RFC791 is wrong proposing to prolongate timer each fragment arrival 837b2fd5321SPavel Emelyanov * by TTL. 838b2fd5321SPavel Emelyanov */ 839b2fd5321SPavel Emelyanov net->ipv4.frags.timeout = IP_FRAG_TIME; 840b2fd5321SPavel Emelyanov 841e5a2bb84SPavel Emelyanov inet_frags_init_net(&net->ipv4.frags); 842e5a2bb84SPavel Emelyanov 8430a64b4b8SPavel Emelyanov return ip4_frags_ns_ctl_register(net); 8448d8354d2SPavel Emelyanov } 8458d8354d2SPavel Emelyanov 8462c8c1e72SAlexey Dobriyan static void __net_exit ipv4_frags_exit_net(struct net *net) 84781566e83SPavel Emelyanov { 8480a64b4b8SPavel Emelyanov ip4_frags_ns_ctl_unregister(net); 84981566e83SPavel Emelyanov inet_frags_exit_net(&net->ipv4.frags, &ip4_frags); 85081566e83SPavel Emelyanov } 85181566e83SPavel Emelyanov 85281566e83SPavel Emelyanov static struct pernet_operations ip4_frags_ops = { 85381566e83SPavel Emelyanov .init = ipv4_frags_init_net, 85481566e83SPavel Emelyanov .exit = ipv4_frags_exit_net, 85581566e83SPavel Emelyanov }; 85681566e83SPavel Emelyanov 857b7aa0bf7SEric Dumazet void __init ipfrag_init(void) 8581da177e4SLinus Torvalds { 8597d291ebbSPavel Emelyanov ip4_frags_ctl_register(); 86081566e83SPavel Emelyanov register_pernet_subsys(&ip4_frags_ops); 861321a3a99SPavel Emelyanov ip4_frags.hashfn = ip4_hashfn; 862c6fda282SPavel Emelyanov ip4_frags.constructor = ip4_frag_init; 8631e4b8287SPavel Emelyanov ip4_frags.destructor = ip4_frag_free; 8641e4b8287SPavel Emelyanov ip4_frags.skb_free = NULL; 8651e4b8287SPavel Emelyanov ip4_frags.qsize = sizeof(struct ipq); 866abd6523dSPavel Emelyanov ip4_frags.match = ip4_frag_match; 867e521db9dSPavel Emelyanov ip4_frags.frag_expire = ip_expire; 868d4ad4d22SNikolay Aleksandrov ip4_frags.frags_cache_name = ip_frag_cache_name; 869d4ad4d22SNikolay Aleksandrov if (inet_frags_init(&ip4_frags)) 870d4ad4d22SNikolay Aleksandrov panic("IP: failed to allocate ip4_frags cache\n"); 8711da177e4SLinus Torvalds } 872