1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * INET An implementation of the TCP/IP protocol suite for the LINUX 41da177e4SLinus Torvalds * operating system. INET is implemented using the BSD Socket 51da177e4SLinus Torvalds * interface as the means of communication with the user level. 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * The IP fragmentation functionality. 81da177e4SLinus Torvalds * 91da177e4SLinus Torvalds * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG> 10113aa838SAlan Cox * Alan Cox <alan@lxorguk.ukuu.org.uk> 111da177e4SLinus Torvalds * 121da177e4SLinus Torvalds * Fixes: 131da177e4SLinus Torvalds * Alan Cox : Split from ip.c , see ip_input.c for history. 141da177e4SLinus Torvalds * David S. Miller : Begin massive cleanup... 151da177e4SLinus Torvalds * Andi Kleen : Add sysctls. 161da177e4SLinus Torvalds * xxxx : Overlapfrag bug. 171da177e4SLinus Torvalds * Ultima : ip_expire() kernel panic. 181da177e4SLinus Torvalds * Bill Hawes : Frag accounting and evictor fixes. 191da177e4SLinus Torvalds * John McDonald : 0 length frag bug. 201da177e4SLinus Torvalds * Alexey Kuznetsov: SMP races, threading, cleanup. 211da177e4SLinus Torvalds * Patrick McHardy : LRU queue of frag heads for evictor. 221da177e4SLinus Torvalds */ 231da177e4SLinus Torvalds 24afd46503SJoe Perches #define pr_fmt(fmt) "IPv4: " fmt 25afd46503SJoe Perches 2689cee8b1SHerbert Xu #include <linux/compiler.h> 271da177e4SLinus Torvalds #include <linux/module.h> 281da177e4SLinus Torvalds #include <linux/types.h> 291da177e4SLinus Torvalds #include <linux/mm.h> 301da177e4SLinus Torvalds #include <linux/jiffies.h> 311da177e4SLinus Torvalds #include <linux/skbuff.h> 321da177e4SLinus Torvalds #include <linux/list.h> 331da177e4SLinus Torvalds #include <linux/ip.h> 341da177e4SLinus Torvalds #include <linux/icmp.h> 351da177e4SLinus Torvalds #include <linux/netdevice.h> 361da177e4SLinus Torvalds #include <linux/jhash.h> 371da177e4SLinus Torvalds #include <linux/random.h> 385a0e3ad6STejun Heo #include <linux/slab.h> 39e9017b55SShan Wei #include <net/route.h> 40e9017b55SShan Wei #include <net/dst.h> 411da177e4SLinus Torvalds #include <net/sock.h> 421da177e4SLinus Torvalds #include <net/ip.h> 431da177e4SLinus Torvalds #include <net/icmp.h> 441da177e4SLinus Torvalds #include <net/checksum.h> 4589cee8b1SHerbert Xu #include <net/inetpeer.h> 465ab11c98SPavel Emelyanov #include <net/inet_frag.h> 471da177e4SLinus Torvalds #include <linux/tcp.h> 481da177e4SLinus Torvalds #include <linux/udp.h> 491da177e4SLinus Torvalds #include <linux/inet.h> 501da177e4SLinus Torvalds #include <linux/netfilter_ipv4.h> 516623e3b2SEric Dumazet #include <net/inet_ecn.h> 52385add90SDavid Ahern #include <net/l3mdev.h> 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6 551da177e4SLinus Torvalds * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c 561da177e4SLinus Torvalds * as well. Or notify me, at least. --ANK 571da177e4SLinus Torvalds */ 58d4ad4d22SNikolay Aleksandrov static const char ip_frag_cache_name[] = "ip4-frags"; 5989cee8b1SHerbert Xu 60353c9cb3SPeter Oskolkov /* Use skb->cb to track consecutive/adjacent fragments coming at 61353c9cb3SPeter Oskolkov * the end of the queue. Nodes in the rb-tree queue will 62353c9cb3SPeter Oskolkov * contain "runs" of one or more adjacent fragments. 63353c9cb3SPeter Oskolkov * 64353c9cb3SPeter Oskolkov * Invariants: 65353c9cb3SPeter Oskolkov * - next_frag is NULL at the tail of a "run"; 66353c9cb3SPeter Oskolkov * - the head of a "run" has the sum of all fragment lengths in frag_run_len. 67353c9cb3SPeter Oskolkov */ 68353c9cb3SPeter Oskolkov struct ipfrag_skb_cb { 69353c9cb3SPeter Oskolkov struct inet_skb_parm h; 70353c9cb3SPeter Oskolkov struct sk_buff *next_frag; 71353c9cb3SPeter Oskolkov int frag_run_len; 72353c9cb3SPeter Oskolkov }; 73353c9cb3SPeter Oskolkov 74353c9cb3SPeter Oskolkov #define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb)) 75353c9cb3SPeter Oskolkov 76353c9cb3SPeter Oskolkov static void ip4_frag_init_run(struct sk_buff *skb) 77353c9cb3SPeter Oskolkov { 78353c9cb3SPeter Oskolkov BUILD_BUG_ON(sizeof(struct ipfrag_skb_cb) > sizeof(skb->cb)); 79353c9cb3SPeter Oskolkov 80353c9cb3SPeter Oskolkov FRAG_CB(skb)->next_frag = NULL; 81353c9cb3SPeter Oskolkov FRAG_CB(skb)->frag_run_len = skb->len; 82353c9cb3SPeter Oskolkov } 83353c9cb3SPeter Oskolkov 84353c9cb3SPeter Oskolkov /* Append skb to the last "run". */ 85353c9cb3SPeter Oskolkov static void ip4_frag_append_to_last_run(struct inet_frag_queue *q, 86353c9cb3SPeter Oskolkov struct sk_buff *skb) 87353c9cb3SPeter Oskolkov { 88353c9cb3SPeter Oskolkov RB_CLEAR_NODE(&skb->rbnode); 89353c9cb3SPeter Oskolkov FRAG_CB(skb)->next_frag = NULL; 90353c9cb3SPeter Oskolkov 91353c9cb3SPeter Oskolkov FRAG_CB(q->last_run_head)->frag_run_len += skb->len; 92353c9cb3SPeter Oskolkov FRAG_CB(q->fragments_tail)->next_frag = skb; 93353c9cb3SPeter Oskolkov q->fragments_tail = skb; 94353c9cb3SPeter Oskolkov } 95353c9cb3SPeter Oskolkov 96353c9cb3SPeter Oskolkov /* Create a new "run" with the skb. */ 97353c9cb3SPeter Oskolkov static void ip4_frag_create_run(struct inet_frag_queue *q, struct sk_buff *skb) 98353c9cb3SPeter Oskolkov { 99353c9cb3SPeter Oskolkov if (q->last_run_head) 100353c9cb3SPeter Oskolkov rb_link_node(&skb->rbnode, &q->last_run_head->rbnode, 101353c9cb3SPeter Oskolkov &q->last_run_head->rbnode.rb_right); 102353c9cb3SPeter Oskolkov else 103353c9cb3SPeter Oskolkov rb_link_node(&skb->rbnode, NULL, &q->rb_fragments.rb_node); 104353c9cb3SPeter Oskolkov rb_insert_color(&skb->rbnode, &q->rb_fragments); 105353c9cb3SPeter Oskolkov 106353c9cb3SPeter Oskolkov ip4_frag_init_run(skb); 107353c9cb3SPeter Oskolkov q->fragments_tail = skb; 108353c9cb3SPeter Oskolkov q->last_run_head = skb; 109353c9cb3SPeter Oskolkov } 110353c9cb3SPeter Oskolkov 1111da177e4SLinus Torvalds /* Describe an entry in the "incomplete datagrams" queue. */ 1121da177e4SLinus Torvalds struct ipq { 1135ab11c98SPavel Emelyanov struct inet_frag_queue q; 1145ab11c98SPavel Emelyanov 1156623e3b2SEric Dumazet u8 ecn; /* RFC3168 support */ 116d6b915e2SFlorian Westphal u16 max_df_size; /* largest frag with DF set seen */ 11789cee8b1SHerbert Xu int iif; 11889cee8b1SHerbert Xu unsigned int rid; 11989cee8b1SHerbert Xu struct inet_peer *peer; 1201da177e4SLinus Torvalds }; 1211da177e4SLinus Torvalds 122aa1f731eSFabian Frederick static u8 ip4_frag_ecn(u8 tos) 1236623e3b2SEric Dumazet { 1245173cc05SEric Dumazet return 1 << (tos & INET_ECN_MASK); 1256623e3b2SEric Dumazet } 1266623e3b2SEric Dumazet 1277eb95156SPavel Emelyanov static struct inet_frags ip4_frags; 1281da177e4SLinus Torvalds 129a4fd284aSPeter Oskolkov static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb, 130a4fd284aSPeter Oskolkov struct sk_buff *prev_tail, struct net_device *dev); 1311706d587SHerbert Xu 132abd6523dSPavel Emelyanov 13336c77782SFlorian Westphal static void ip4_frag_init(struct inet_frag_queue *q, const void *a) 134c6fda282SPavel Emelyanov { 135c6fda282SPavel Emelyanov struct ipq *qp = container_of(q, struct ipq, q); 13654db0cc2SGao feng struct netns_ipv4 *ipv4 = container_of(q->net, struct netns_ipv4, 13754db0cc2SGao feng frags); 13854db0cc2SGao feng struct net *net = container_of(ipv4, struct net, ipv4); 13954db0cc2SGao feng 140648700f7SEric Dumazet const struct frag_v4_compare_key *key = a; 141c6fda282SPavel Emelyanov 142648700f7SEric Dumazet q->key.v4 = *key; 143648700f7SEric Dumazet qp->ecn = 0; 1440fbf4cb2SNikolay Borisov qp->peer = q->net->max_dist ? 145648700f7SEric Dumazet inet_getpeer_v4(net->ipv4.peers, key->saddr, key->vif, 1) : 146192132b9SDavid Ahern NULL; 147c6fda282SPavel Emelyanov } 148c6fda282SPavel Emelyanov 149aa1f731eSFabian Frederick static void ip4_frag_free(struct inet_frag_queue *q) 1501da177e4SLinus Torvalds { 1511e4b8287SPavel Emelyanov struct ipq *qp; 1521e4b8287SPavel Emelyanov 1531e4b8287SPavel Emelyanov qp = container_of(q, struct ipq, q); 1541e4b8287SPavel Emelyanov if (qp->peer) 1551e4b8287SPavel Emelyanov inet_putpeer(qp->peer); 1561da177e4SLinus Torvalds } 1571da177e4SLinus Torvalds 1581da177e4SLinus Torvalds 1591da177e4SLinus Torvalds /* Destruction primitives. */ 1601da177e4SLinus Torvalds 161aa1f731eSFabian Frederick static void ipq_put(struct ipq *ipq) 1621da177e4SLinus Torvalds { 163093ba729SEric Dumazet inet_frag_put(&ipq->q); 1641da177e4SLinus Torvalds } 1651da177e4SLinus Torvalds 1661da177e4SLinus Torvalds /* Kill ipq entry. It is not destroyed immediately, 1671da177e4SLinus Torvalds * because caller (and someone more) holds reference count. 1681da177e4SLinus Torvalds */ 1691da177e4SLinus Torvalds static void ipq_kill(struct ipq *ipq) 1701da177e4SLinus Torvalds { 171093ba729SEric Dumazet inet_frag_kill(&ipq->q); 1721da177e4SLinus Torvalds } 1731da177e4SLinus Torvalds 1745cf42280SAndy Zhou static bool frag_expire_skip_icmp(u32 user) 1755cf42280SAndy Zhou { 1765cf42280SAndy Zhou return user == IP_DEFRAG_AF_PACKET || 1775cf42280SAndy Zhou ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_IN, 1788bc04864SAndy Zhou __IP_DEFRAG_CONNTRACK_IN_END) || 1798bc04864SAndy Zhou ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_BRIDGE_IN, 1808bc04864SAndy Zhou __IP_DEFRAG_CONNTRACK_BRIDGE_IN); 1815cf42280SAndy Zhou } 1825cf42280SAndy Zhou 1831da177e4SLinus Torvalds /* 1841da177e4SLinus Torvalds * Oops, a fragment queue timed out. Kill it and send an ICMP reply. 1851da177e4SLinus Torvalds */ 18678802011SKees Cook static void ip_expire(struct timer_list *t) 1871da177e4SLinus Torvalds { 18878802011SKees Cook struct inet_frag_queue *frag = from_timer(frag, t, timer); 189399d1404SEric Dumazet const struct iphdr *iph; 190fa0f5273SPeter Oskolkov struct sk_buff *head = NULL; 19184a3aa00SPavel Emelyanov struct net *net; 192399d1404SEric Dumazet struct ipq *qp; 193399d1404SEric Dumazet int err; 194e521db9dSPavel Emelyanov 19578802011SKees Cook qp = container_of(frag, struct ipq, q); 19684a3aa00SPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 1971da177e4SLinus Torvalds 198ec4fbd64SEric Dumazet rcu_read_lock(); 1995ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 2001da177e4SLinus Torvalds 20106aa8b8aSNikolay Aleksandrov if (qp->q.flags & INET_FRAG_COMPLETE) 2021da177e4SLinus Torvalds goto out; 2031da177e4SLinus Torvalds 2041da177e4SLinus Torvalds ipq_kill(qp); 205b45386efSEric Dumazet __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 206b45386efSEric Dumazet __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT); 2072e404f63SNikolay Aleksandrov 20870837ffeSDan Carpenter if (!(qp->q.flags & INET_FRAG_FIRST_IN)) 2092e404f63SNikolay Aleksandrov goto out; 2102e404f63SNikolay Aleksandrov 211fa0f5273SPeter Oskolkov /* sk_buff::dev and sk_buff::rbnode are unionized. So we 212fa0f5273SPeter Oskolkov * pull the head out of the tree in order to be able to 213fa0f5273SPeter Oskolkov * deal with head->dev. 214fa0f5273SPeter Oskolkov */ 215fa0f5273SPeter Oskolkov if (qp->q.fragments) { 216fa0f5273SPeter Oskolkov head = qp->q.fragments; 217fa0f5273SPeter Oskolkov qp->q.fragments = head->next; 218fa0f5273SPeter Oskolkov } else { 219fa0f5273SPeter Oskolkov head = skb_rb_first(&qp->q.rb_fragments); 220fa0f5273SPeter Oskolkov if (!head) 221fa0f5273SPeter Oskolkov goto out; 222a4fd284aSPeter Oskolkov if (FRAG_CB(head)->next_frag) 223a4fd284aSPeter Oskolkov rb_replace_node(&head->rbnode, 224a4fd284aSPeter Oskolkov &FRAG_CB(head)->next_frag->rbnode, 225a4fd284aSPeter Oskolkov &qp->q.rb_fragments); 226a4fd284aSPeter Oskolkov else 227fa0f5273SPeter Oskolkov rb_erase(&head->rbnode, &qp->q.rb_fragments); 228fa0f5273SPeter Oskolkov memset(&head->rbnode, 0, sizeof(head->rbnode)); 229fa0f5273SPeter Oskolkov barrier(); 230fa0f5273SPeter Oskolkov } 231fa0f5273SPeter Oskolkov if (head == qp->q.fragments_tail) 232fa0f5273SPeter Oskolkov qp->q.fragments_tail = NULL; 233fa0f5273SPeter Oskolkov 234fa0f5273SPeter Oskolkov sub_frag_mem_limit(qp->q.net, head->truesize); 235fa0f5273SPeter Oskolkov 23669df9d59SEric Dumazet head->dev = dev_get_by_index_rcu(net, qp->iif); 237e9017b55SShan Wei if (!head->dev) 238ec4fbd64SEric Dumazet goto out; 239ec4fbd64SEric Dumazet 240e9017b55SShan Wei 24197599dc7SEric Dumazet /* skb has no dst, perform route lookup again */ 24264f3b9e2SEric Dumazet iph = ip_hdr(head); 243c6cffba4SDavid S. Miller err = ip_route_input_noref(head, iph->daddr, iph->saddr, 244c10237e0SDavid S. Miller iph->tos, head->dev); 24564f3b9e2SEric Dumazet if (err) 246ec4fbd64SEric Dumazet goto out; 247e9017b55SShan Wei 2482e404f63SNikolay Aleksandrov /* Only an end host needs to send an ICMP 249e9017b55SShan Wei * "Fragment Reassembly Timeout" message, per RFC792. 250e9017b55SShan Wei */ 251648700f7SEric Dumazet if (frag_expire_skip_icmp(qp->q.key.v4.user) && 2525cf42280SAndy Zhou (skb_rtable(head)->rt_type != RTN_LOCAL)) 253ec4fbd64SEric Dumazet goto out; 254ec4fbd64SEric Dumazet 255ec4fbd64SEric Dumazet spin_unlock(&qp->q.lock); 2561eec5d56SEric Dumazet icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); 257ec4fbd64SEric Dumazet goto out_rcu_unlock; 2581eec5d56SEric Dumazet 2591da177e4SLinus Torvalds out: 2605ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 261ec4fbd64SEric Dumazet out_rcu_unlock: 262ec4fbd64SEric Dumazet rcu_read_unlock(); 263fa0f5273SPeter Oskolkov kfree_skb(head); 2644b6cb5d8SPavel Emelyanov ipq_put(qp); 2651da177e4SLinus Torvalds } 2661da177e4SLinus Torvalds 267abd6523dSPavel Emelyanov /* Find the correct entry in the "incomplete datagrams" queue for 268abd6523dSPavel Emelyanov * this IP datagram, and create new one, if nothing is found. 269abd6523dSPavel Emelyanov */ 2709972f134SDavid Ahern static struct ipq *ip_find(struct net *net, struct iphdr *iph, 2719972f134SDavid Ahern u32 user, int vif) 2721da177e4SLinus Torvalds { 273648700f7SEric Dumazet struct frag_v4_compare_key key = { 274648700f7SEric Dumazet .saddr = iph->saddr, 275648700f7SEric Dumazet .daddr = iph->daddr, 276648700f7SEric Dumazet .user = user, 277648700f7SEric Dumazet .vif = vif, 278648700f7SEric Dumazet .id = iph->id, 279648700f7SEric Dumazet .protocol = iph->protocol, 280648700f7SEric Dumazet }; 281c6fda282SPavel Emelyanov struct inet_frag_queue *q; 2821da177e4SLinus Torvalds 283648700f7SEric Dumazet q = inet_frag_find(&net->ipv4.frags, &key); 2842d44ed22SEric Dumazet if (!q) 2851da177e4SLinus Torvalds return NULL; 2862d44ed22SEric Dumazet 2875a3da1feSHannes Frederic Sowa return container_of(q, struct ipq, q); 2885a3da1feSHannes Frederic Sowa } 2891da177e4SLinus Torvalds 29089cee8b1SHerbert Xu /* Is the fragment too far ahead to be part of ipq? */ 291aa1f731eSFabian Frederick static int ip_frag_too_far(struct ipq *qp) 29289cee8b1SHerbert Xu { 29389cee8b1SHerbert Xu struct inet_peer *peer = qp->peer; 2940fbf4cb2SNikolay Borisov unsigned int max = qp->q.net->max_dist; 29589cee8b1SHerbert Xu unsigned int start, end; 29689cee8b1SHerbert Xu 29789cee8b1SHerbert Xu int rc; 29889cee8b1SHerbert Xu 29989cee8b1SHerbert Xu if (!peer || !max) 30089cee8b1SHerbert Xu return 0; 30189cee8b1SHerbert Xu 30289cee8b1SHerbert Xu start = qp->rid; 30389cee8b1SHerbert Xu end = atomic_inc_return(&peer->rid); 30489cee8b1SHerbert Xu qp->rid = end; 30589cee8b1SHerbert Xu 306fa0f5273SPeter Oskolkov rc = qp->q.fragments_tail && (end - start) > max; 30789cee8b1SHerbert Xu 30889cee8b1SHerbert Xu if (rc) { 3097c73a6faSPavel Emelyanov struct net *net; 3107c73a6faSPavel Emelyanov 3117c73a6faSPavel Emelyanov net = container_of(qp->q.net, struct net, ipv4.frags); 312b45386efSEric Dumazet __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 31389cee8b1SHerbert Xu } 31489cee8b1SHerbert Xu 31589cee8b1SHerbert Xu return rc; 31689cee8b1SHerbert Xu } 31789cee8b1SHerbert Xu 31889cee8b1SHerbert Xu static int ip_frag_reinit(struct ipq *qp) 31989cee8b1SHerbert Xu { 320d433673eSJesper Dangaard Brouer unsigned int sum_truesize = 0; 32189cee8b1SHerbert Xu 322b2fd5321SPavel Emelyanov if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) { 323edcb6918SReshetova, Elena refcount_inc(&qp->q.refcnt); 32489cee8b1SHerbert Xu return -ETIMEDOUT; 32589cee8b1SHerbert Xu } 32689cee8b1SHerbert Xu 327a4fd284aSPeter Oskolkov sum_truesize = inet_frag_rbtree_purge(&qp->q.rb_fragments); 3280e60d245SFlorian Westphal sub_frag_mem_limit(qp->q.net, sum_truesize); 32989cee8b1SHerbert Xu 33006aa8b8aSNikolay Aleksandrov qp->q.flags = 0; 3315ab11c98SPavel Emelyanov qp->q.len = 0; 3325ab11c98SPavel Emelyanov qp->q.meat = 0; 3335ab11c98SPavel Emelyanov qp->q.fragments = NULL; 334fa0f5273SPeter Oskolkov qp->q.rb_fragments = RB_ROOT; 335d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 336a4fd284aSPeter Oskolkov qp->q.last_run_head = NULL; 33789cee8b1SHerbert Xu qp->iif = 0; 3386623e3b2SEric Dumazet qp->ecn = 0; 33989cee8b1SHerbert Xu 34089cee8b1SHerbert Xu return 0; 34189cee8b1SHerbert Xu } 34289cee8b1SHerbert Xu 3431da177e4SLinus Torvalds /* Add new segment to existing queue. */ 3441706d587SHerbert Xu static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) 3451da177e4SLinus Torvalds { 3467969e5c4SPeter Oskolkov struct net *net = container_of(qp->q.net, struct net, ipv4.frags); 347fa0f5273SPeter Oskolkov struct rb_node **rbn, *parent; 348a4fd284aSPeter Oskolkov struct sk_buff *skb1, *prev_tail; 3491706d587SHerbert Xu struct net_device *dev; 350d6b915e2SFlorian Westphal unsigned int fragsize; 3511da177e4SLinus Torvalds int flags, offset; 3521da177e4SLinus Torvalds int ihl, end; 3531706d587SHerbert Xu int err = -ENOENT; 3546623e3b2SEric Dumazet u8 ecn; 3551da177e4SLinus Torvalds 35606aa8b8aSNikolay Aleksandrov if (qp->q.flags & INET_FRAG_COMPLETE) 3571da177e4SLinus Torvalds goto err; 3581da177e4SLinus Torvalds 35989cee8b1SHerbert Xu if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && 3601706d587SHerbert Xu unlikely(ip_frag_too_far(qp)) && 3611706d587SHerbert Xu unlikely(err = ip_frag_reinit(qp))) { 36289cee8b1SHerbert Xu ipq_kill(qp); 36389cee8b1SHerbert Xu goto err; 36489cee8b1SHerbert Xu } 36589cee8b1SHerbert Xu 3666623e3b2SEric Dumazet ecn = ip4_frag_ecn(ip_hdr(skb)->tos); 367eddc9ec5SArnaldo Carvalho de Melo offset = ntohs(ip_hdr(skb)->frag_off); 3681da177e4SLinus Torvalds flags = offset & ~IP_OFFSET; 3691da177e4SLinus Torvalds offset &= IP_OFFSET; 3701da177e4SLinus Torvalds offset <<= 3; /* offset is in 8-byte chunks */ 371c9bdd4b5SArnaldo Carvalho de Melo ihl = ip_hdrlen(skb); 3721da177e4SLinus Torvalds 3731da177e4SLinus Torvalds /* Determine the position of this fragment. */ 3740848f642SEdward Hyunkoo Jee end = offset + skb->len - skb_network_offset(skb) - ihl; 3751706d587SHerbert Xu err = -EINVAL; 3761da177e4SLinus Torvalds 3771da177e4SLinus Torvalds /* Is this the final fragment? */ 3781da177e4SLinus Torvalds if ((flags & IP_MF) == 0) { 3791da177e4SLinus Torvalds /* If we already have some bits beyond end 38042b2aa86SJustin P. Mattock * or have different end, the segment is corrupted. 3811da177e4SLinus Torvalds */ 3825ab11c98SPavel Emelyanov if (end < qp->q.len || 38306aa8b8aSNikolay Aleksandrov ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len)) 3840ff89efbSPeter Oskolkov goto discard_qp; 38506aa8b8aSNikolay Aleksandrov qp->q.flags |= INET_FRAG_LAST_IN; 3865ab11c98SPavel Emelyanov qp->q.len = end; 3871da177e4SLinus Torvalds } else { 3881da177e4SLinus Torvalds if (end&7) { 3891da177e4SLinus Torvalds end &= ~7; 3901da177e4SLinus Torvalds if (skb->ip_summed != CHECKSUM_UNNECESSARY) 3911da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 3921da177e4SLinus Torvalds } 3935ab11c98SPavel Emelyanov if (end > qp->q.len) { 3941da177e4SLinus Torvalds /* Some bits beyond end -> corruption. */ 39506aa8b8aSNikolay Aleksandrov if (qp->q.flags & INET_FRAG_LAST_IN) 3960ff89efbSPeter Oskolkov goto discard_qp; 3975ab11c98SPavel Emelyanov qp->q.len = end; 3981da177e4SLinus Torvalds } 3991da177e4SLinus Torvalds } 4001da177e4SLinus Torvalds if (end == offset) 4010ff89efbSPeter Oskolkov goto discard_qp; 4021da177e4SLinus Torvalds 4031706d587SHerbert Xu err = -ENOMEM; 4040848f642SEdward Hyunkoo Jee if (!pskb_pull(skb, skb_network_offset(skb) + ihl)) 4050ff89efbSPeter Oskolkov goto discard_qp; 4061706d587SHerbert Xu 4071706d587SHerbert Xu err = pskb_trim_rcsum(skb, end - offset); 4081706d587SHerbert Xu if (err) 4090ff89efbSPeter Oskolkov goto discard_qp; 4101da177e4SLinus Torvalds 411fa0f5273SPeter Oskolkov /* Note : skb->rbnode and skb->dev share the same location. */ 412fa0f5273SPeter Oskolkov dev = skb->dev; 413fa0f5273SPeter Oskolkov /* Makes sure compiler wont do silly aliasing games */ 414fa0f5273SPeter Oskolkov barrier(); 4151da177e4SLinus Torvalds 4167969e5c4SPeter Oskolkov /* RFC5722, Section 4, amended by Errata ID : 3089 4177969e5c4SPeter Oskolkov * When reassembling an IPv6 datagram, if 4187969e5c4SPeter Oskolkov * one or more its constituent fragments is determined to be an 4197969e5c4SPeter Oskolkov * overlapping fragment, the entire datagram (and any constituent 4207969e5c4SPeter Oskolkov * fragments) MUST be silently discarded. 4217969e5c4SPeter Oskolkov * 422fa0f5273SPeter Oskolkov * We do the same here for IPv4 (and increment an snmp counter). 4231da177e4SLinus Torvalds */ 4241da177e4SLinus Torvalds 4250ff89efbSPeter Oskolkov err = -EINVAL; 426fa0f5273SPeter Oskolkov /* Find out where to put this fragment. */ 427a4fd284aSPeter Oskolkov prev_tail = qp->q.fragments_tail; 428a4fd284aSPeter Oskolkov if (!prev_tail) 429a4fd284aSPeter Oskolkov ip4_frag_create_run(&qp->q, skb); /* First fragment. */ 430a4fd284aSPeter Oskolkov else if (prev_tail->ip_defrag_offset + prev_tail->len < end) { 431a4fd284aSPeter Oskolkov /* This is the common case: skb goes to the end. */ 432fa0f5273SPeter Oskolkov /* Detect and discard overlaps. */ 433a4fd284aSPeter Oskolkov if (offset < prev_tail->ip_defrag_offset + prev_tail->len) 4340ff89efbSPeter Oskolkov goto overlap; 435a4fd284aSPeter Oskolkov if (offset == prev_tail->ip_defrag_offset + prev_tail->len) 436a4fd284aSPeter Oskolkov ip4_frag_append_to_last_run(&qp->q, skb); 437a4fd284aSPeter Oskolkov else 438a4fd284aSPeter Oskolkov ip4_frag_create_run(&qp->q, skb); 439fa0f5273SPeter Oskolkov } else { 440a4fd284aSPeter Oskolkov /* Binary search. Note that skb can become the first fragment, 441a4fd284aSPeter Oskolkov * but not the last (covered above). 442a4fd284aSPeter Oskolkov */ 443fa0f5273SPeter Oskolkov rbn = &qp->q.rb_fragments.rb_node; 444fa0f5273SPeter Oskolkov do { 445fa0f5273SPeter Oskolkov parent = *rbn; 446fa0f5273SPeter Oskolkov skb1 = rb_to_skb(parent); 447fa0f5273SPeter Oskolkov if (end <= skb1->ip_defrag_offset) 448fa0f5273SPeter Oskolkov rbn = &parent->rb_left; 449a4fd284aSPeter Oskolkov else if (offset >= skb1->ip_defrag_offset + 450a4fd284aSPeter Oskolkov FRAG_CB(skb1)->frag_run_len) 451fa0f5273SPeter Oskolkov rbn = &parent->rb_right; 452fa0f5273SPeter Oskolkov else /* Found an overlap with skb1. */ 4530ff89efbSPeter Oskolkov goto overlap; 454fa0f5273SPeter Oskolkov } while (*rbn); 455fa0f5273SPeter Oskolkov /* Here we have parent properly set, and rbn pointing to 456a4fd284aSPeter Oskolkov * one of its NULL left/right children. Insert skb. 457a4fd284aSPeter Oskolkov */ 458a4fd284aSPeter Oskolkov ip4_frag_init_run(skb); 459fa0f5273SPeter Oskolkov rb_link_node(&skb->rbnode, parent, rbn); 460fa0f5273SPeter Oskolkov rb_insert_color(&skb->rbnode, &qp->q.rb_fragments); 461a4fd284aSPeter Oskolkov } 4621da177e4SLinus Torvalds 463bf663371SEric Dumazet if (dev) 464bf663371SEric Dumazet qp->iif = dev->ifindex; 465bf663371SEric Dumazet skb->ip_defrag_offset = offset; 4661da177e4SLinus Torvalds 4675ab11c98SPavel Emelyanov qp->q.stamp = skb->tstamp; 4685ab11c98SPavel Emelyanov qp->q.meat += skb->len; 4696623e3b2SEric Dumazet qp->ecn |= ecn; 4700e60d245SFlorian Westphal add_frag_mem_limit(qp->q.net, skb->truesize); 4711da177e4SLinus Torvalds if (offset == 0) 47206aa8b8aSNikolay Aleksandrov qp->q.flags |= INET_FRAG_FIRST_IN; 4731da177e4SLinus Torvalds 474d6b915e2SFlorian Westphal fragsize = skb->len + ihl; 475d6b915e2SFlorian Westphal 476d6b915e2SFlorian Westphal if (fragsize > qp->q.max_size) 477d6b915e2SFlorian Westphal qp->q.max_size = fragsize; 478d6b915e2SFlorian Westphal 4795f2d04f1SPatrick McHardy if (ip_hdr(skb)->frag_off & htons(IP_DF) && 480d6b915e2SFlorian Westphal fragsize > qp->max_df_size) 481d6b915e2SFlorian Westphal qp->max_df_size = fragsize; 4825f2d04f1SPatrick McHardy 48306aa8b8aSNikolay Aleksandrov if (qp->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && 48497599dc7SEric Dumazet qp->q.meat == qp->q.len) { 48597599dc7SEric Dumazet unsigned long orefdst = skb->_skb_refdst; 4861706d587SHerbert Xu 48797599dc7SEric Dumazet skb->_skb_refdst = 0UL; 488a4fd284aSPeter Oskolkov err = ip_frag_reasm(qp, skb, prev_tail, dev); 48997599dc7SEric Dumazet skb->_skb_refdst = orefdst; 4900ff89efbSPeter Oskolkov if (err) 4910ff89efbSPeter Oskolkov inet_frag_kill(&qp->q); 49297599dc7SEric Dumazet return err; 49397599dc7SEric Dumazet } 49497599dc7SEric Dumazet 49597599dc7SEric Dumazet skb_dst_drop(skb); 4961706d587SHerbert Xu return -EINPROGRESS; 4971da177e4SLinus Torvalds 4980ff89efbSPeter Oskolkov overlap: 4990ff89efbSPeter Oskolkov __IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS); 5007969e5c4SPeter Oskolkov discard_qp: 5017969e5c4SPeter Oskolkov inet_frag_kill(&qp->q); 5021da177e4SLinus Torvalds err: 5031da177e4SLinus Torvalds kfree_skb(skb); 5041706d587SHerbert Xu return err; 5051da177e4SLinus Torvalds } 5061da177e4SLinus Torvalds 5071da177e4SLinus Torvalds /* Build a new IP datagram from all its fragments. */ 508fa0f5273SPeter Oskolkov static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb, 509a4fd284aSPeter Oskolkov struct sk_buff *prev_tail, struct net_device *dev) 5101da177e4SLinus Torvalds { 5112bad35b7SJorge Boncompte [DTI2] struct net *net = container_of(qp->q.net, struct net, ipv4.frags); 5121da177e4SLinus Torvalds struct iphdr *iph; 513fa0f5273SPeter Oskolkov struct sk_buff *fp, *head = skb_rb_first(&qp->q.rb_fragments); 514fa0f5273SPeter Oskolkov struct sk_buff **nextp; /* To build frag_list. */ 515fa0f5273SPeter Oskolkov struct rb_node *rbn; 5161da177e4SLinus Torvalds int len; 5171da177e4SLinus Torvalds int ihlen; 5181706d587SHerbert Xu int err; 5195173cc05SEric Dumazet u8 ecn; 5201da177e4SLinus Torvalds 5211da177e4SLinus Torvalds ipq_kill(qp); 5221da177e4SLinus Torvalds 523be991971SHannes Frederic Sowa ecn = ip_frag_ecn_table[qp->ecn]; 5245173cc05SEric Dumazet if (unlikely(ecn == 0xff)) { 5255173cc05SEric Dumazet err = -EINVAL; 5265173cc05SEric Dumazet goto out_fail; 5275173cc05SEric Dumazet } 5281706d587SHerbert Xu /* Make the one we just received the head. */ 529fa0f5273SPeter Oskolkov if (head != skb) { 530fa0f5273SPeter Oskolkov fp = skb_clone(skb, GFP_ATOMIC); 5311706d587SHerbert Xu if (!fp) 5321706d587SHerbert Xu goto out_nomem; 533a4fd284aSPeter Oskolkov FRAG_CB(fp)->next_frag = FRAG_CB(skb)->next_frag; 534a4fd284aSPeter Oskolkov if (RB_EMPTY_NODE(&skb->rbnode)) 535a4fd284aSPeter Oskolkov FRAG_CB(prev_tail)->next_frag = fp; 536a4fd284aSPeter Oskolkov else 537a4fd284aSPeter Oskolkov rb_replace_node(&skb->rbnode, &fp->rbnode, 538a4fd284aSPeter Oskolkov &qp->q.rb_fragments); 539fa0f5273SPeter Oskolkov if (qp->q.fragments_tail == skb) 540d6bebca9SChangli Gao qp->q.fragments_tail = fp; 541fa0f5273SPeter Oskolkov skb_morph(skb, head); 542a4fd284aSPeter Oskolkov FRAG_CB(skb)->next_frag = FRAG_CB(head)->next_frag; 543fa0f5273SPeter Oskolkov rb_replace_node(&head->rbnode, &skb->rbnode, 544fa0f5273SPeter Oskolkov &qp->q.rb_fragments); 545fa0f5273SPeter Oskolkov consume_skb(head); 546fa0f5273SPeter Oskolkov head = skb; 5471706d587SHerbert Xu } 5481706d587SHerbert Xu 549bf663371SEric Dumazet WARN_ON(head->ip_defrag_offset != 0); 5501da177e4SLinus Torvalds 5511da177e4SLinus Torvalds /* Allocate a new buffer for the datagram. */ 552c9bdd4b5SArnaldo Carvalho de Melo ihlen = ip_hdrlen(head); 5535ab11c98SPavel Emelyanov len = ihlen + qp->q.len; 5541da177e4SLinus Torvalds 5551706d587SHerbert Xu err = -E2BIG; 5561da177e4SLinus Torvalds if (len > 65535) 5571da177e4SLinus Torvalds goto out_oversize; 5581da177e4SLinus Torvalds 5591da177e4SLinus Torvalds /* Head of list must not be cloned. */ 56014bbd6a5SPravin B Shelar if (skb_unclone(head, GFP_ATOMIC)) 5611da177e4SLinus Torvalds goto out_nomem; 5621da177e4SLinus Torvalds 5631da177e4SLinus Torvalds /* If the first fragment is fragmented itself, we split 5641da177e4SLinus Torvalds * it to two chunks: the first with data and paged part 5651da177e4SLinus Torvalds * and the second, holding only fragments. */ 56621dc3301SDavid S. Miller if (skb_has_frag_list(head)) { 5671da177e4SLinus Torvalds struct sk_buff *clone; 5681da177e4SLinus Torvalds int i, plen = 0; 5691da177e4SLinus Torvalds 57051456b29SIan Morris clone = alloc_skb(0, GFP_ATOMIC); 57151456b29SIan Morris if (!clone) 5721da177e4SLinus Torvalds goto out_nomem; 5731da177e4SLinus Torvalds skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 574d7fcf1a5SDavid S. Miller skb_frag_list_init(head); 5751da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(head)->nr_frags; i++) 5769e903e08SEric Dumazet plen += skb_frag_size(&skb_shinfo(head)->frags[i]); 5771da177e4SLinus Torvalds clone->len = clone->data_len = head->data_len - plen; 578a4fd284aSPeter Oskolkov head->truesize += clone->truesize; 5791da177e4SLinus Torvalds clone->csum = 0; 5801da177e4SLinus Torvalds clone->ip_summed = head->ip_summed; 5810e60d245SFlorian Westphal add_frag_mem_limit(qp->q.net, clone->truesize); 582fa0f5273SPeter Oskolkov skb_shinfo(head)->frag_list = clone; 583fa0f5273SPeter Oskolkov nextp = &clone->next; 584fa0f5273SPeter Oskolkov } else { 585fa0f5273SPeter Oskolkov nextp = &skb_shinfo(head)->frag_list; 5861da177e4SLinus Torvalds } 5871da177e4SLinus Torvalds 588d56f90a7SArnaldo Carvalho de Melo skb_push(head, head->data - skb_network_header(head)); 5891da177e4SLinus Torvalds 590fa0f5273SPeter Oskolkov /* Traverse the tree in order, to build frag_list. */ 591a4fd284aSPeter Oskolkov fp = FRAG_CB(head)->next_frag; 592fa0f5273SPeter Oskolkov rbn = rb_next(&head->rbnode); 593fa0f5273SPeter Oskolkov rb_erase(&head->rbnode, &qp->q.rb_fragments); 594a4fd284aSPeter Oskolkov while (rbn || fp) { 595a4fd284aSPeter Oskolkov /* fp points to the next sk_buff in the current run; 596a4fd284aSPeter Oskolkov * rbn points to the next run. 597a4fd284aSPeter Oskolkov */ 598a4fd284aSPeter Oskolkov /* Go through the current run. */ 599a4fd284aSPeter Oskolkov while (fp) { 600fa0f5273SPeter Oskolkov *nextp = fp; 601fa0f5273SPeter Oskolkov nextp = &fp->next; 602fa0f5273SPeter Oskolkov fp->prev = NULL; 603fa0f5273SPeter Oskolkov memset(&fp->rbnode, 0, sizeof(fp->rbnode)); 6045d407b07STaehee Yoo fp->sk = NULL; 60514fe22e3SFlorian Westphal head->data_len += fp->len; 60614fe22e3SFlorian Westphal head->len += fp->len; 6071da177e4SLinus Torvalds if (head->ip_summed != fp->ip_summed) 6081da177e4SLinus Torvalds head->ip_summed = CHECKSUM_NONE; 60984fa7933SPatrick McHardy else if (head->ip_summed == CHECKSUM_COMPLETE) 6101da177e4SLinus Torvalds head->csum = csum_add(head->csum, fp->csum); 6111da177e4SLinus Torvalds head->truesize += fp->truesize; 612a4fd284aSPeter Oskolkov fp = FRAG_CB(fp)->next_frag; 613a4fd284aSPeter Oskolkov } 614a4fd284aSPeter Oskolkov /* Move to the next run. */ 615a4fd284aSPeter Oskolkov if (rbn) { 616a4fd284aSPeter Oskolkov struct rb_node *rbnext = rb_next(rbn); 617a4fd284aSPeter Oskolkov 618a4fd284aSPeter Oskolkov fp = rb_to_skb(rbn); 619a4fd284aSPeter Oskolkov rb_erase(rbn, &qp->q.rb_fragments); 620a4fd284aSPeter Oskolkov rbn = rbnext; 621a4fd284aSPeter Oskolkov } 6221da177e4SLinus Torvalds } 6235510b3c2SDavid S. Miller sub_frag_mem_limit(qp->q.net, head->truesize); 6241da177e4SLinus Torvalds 625fa0f5273SPeter Oskolkov *nextp = NULL; 626a8305bffSDavid S. Miller skb_mark_not_on_list(head); 627fa0f5273SPeter Oskolkov head->prev = NULL; 6281da177e4SLinus Torvalds head->dev = dev; 6295ab11c98SPavel Emelyanov head->tstamp = qp->q.stamp; 630d6b915e2SFlorian Westphal IPCB(head)->frag_max_size = max(qp->max_df_size, qp->q.max_size); 6311da177e4SLinus Torvalds 632eddc9ec5SArnaldo Carvalho de Melo iph = ip_hdr(head); 6331da177e4SLinus Torvalds iph->tot_len = htons(len); 6345173cc05SEric Dumazet iph->tos |= ecn; 635d6b915e2SFlorian Westphal 636d6b915e2SFlorian Westphal /* When we set IP_DF on a refragmented skb we must also force a 637d6b915e2SFlorian Westphal * call to ip_fragment to avoid forwarding a DF-skb of size s while 638d6b915e2SFlorian Westphal * original sender only sent fragments of size f (where f < s). 639d6b915e2SFlorian Westphal * 640d6b915e2SFlorian Westphal * We only set DF/IPSKB_FRAG_PMTU if such DF fragment was the largest 641d6b915e2SFlorian Westphal * frag seen to avoid sending tiny DF-fragments in case skb was built 642d6b915e2SFlorian Westphal * from one very small df-fragment and one large non-df frag. 643d6b915e2SFlorian Westphal */ 644d6b915e2SFlorian Westphal if (qp->max_df_size == qp->q.max_size) { 645d6b915e2SFlorian Westphal IPCB(head)->flags |= IPSKB_FRAG_PMTU; 646d6b915e2SFlorian Westphal iph->frag_off = htons(IP_DF); 647d6b915e2SFlorian Westphal } else { 648d6b915e2SFlorian Westphal iph->frag_off = 0; 649d6b915e2SFlorian Westphal } 650d6b915e2SFlorian Westphal 6510848f642SEdward Hyunkoo Jee ip_send_check(iph); 6520848f642SEdward Hyunkoo Jee 653b45386efSEric Dumazet __IP_INC_STATS(net, IPSTATS_MIB_REASMOKS); 6545ab11c98SPavel Emelyanov qp->q.fragments = NULL; 655fa0f5273SPeter Oskolkov qp->q.rb_fragments = RB_ROOT; 656d6bebca9SChangli Gao qp->q.fragments_tail = NULL; 657a4fd284aSPeter Oskolkov qp->q.last_run_head = NULL; 6581706d587SHerbert Xu return 0; 6591da177e4SLinus Torvalds 6601da177e4SLinus Torvalds out_nomem: 661ba7a46f1SJoe Perches net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp); 66245542479SDavid Howells err = -ENOMEM; 6631da177e4SLinus Torvalds goto out_fail; 6641da177e4SLinus Torvalds out_oversize: 665648700f7SEric Dumazet net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->q.key.v4.saddr); 6661da177e4SLinus Torvalds out_fail: 667b45386efSEric Dumazet __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 6681706d587SHerbert Xu return err; 6691da177e4SLinus Torvalds } 6701da177e4SLinus Torvalds 6711da177e4SLinus Torvalds /* Process an incoming IP datagram fragment. */ 67219bcf9f2SEric W. Biederman int ip_defrag(struct net *net, struct sk_buff *skb, u32 user) 6731da177e4SLinus Torvalds { 6749972f134SDavid Ahern struct net_device *dev = skb->dev ? : skb_dst(skb)->dev; 675385add90SDavid Ahern int vif = l3mdev_master_ifindex_rcu(dev); 6761da177e4SLinus Torvalds struct ipq *qp; 6771da177e4SLinus Torvalds 678b45386efSEric Dumazet __IP_INC_STATS(net, IPSTATS_MIB_REASMREQDS); 6798282f274SJoe Stringer skb_orphan(skb); 6801da177e4SLinus Torvalds 6811da177e4SLinus Torvalds /* Lookup (or create) queue header */ 6829972f134SDavid Ahern qp = ip_find(net, ip_hdr(skb), user, vif); 68300db4124SIan Morris if (qp) { 6841706d587SHerbert Xu int ret; 6851da177e4SLinus Torvalds 6865ab11c98SPavel Emelyanov spin_lock(&qp->q.lock); 6871da177e4SLinus Torvalds 6881706d587SHerbert Xu ret = ip_frag_queue(qp, skb); 6891da177e4SLinus Torvalds 6905ab11c98SPavel Emelyanov spin_unlock(&qp->q.lock); 6914b6cb5d8SPavel Emelyanov ipq_put(qp); 692776c729eSHerbert Xu return ret; 6931da177e4SLinus Torvalds } 6941da177e4SLinus Torvalds 695b45386efSEric Dumazet __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 6961da177e4SLinus Torvalds kfree_skb(skb); 697776c729eSHerbert Xu return -ENOMEM; 6981da177e4SLinus Torvalds } 6994bc2f18bSEric Dumazet EXPORT_SYMBOL(ip_defrag); 7001da177e4SLinus Torvalds 70119bcf9f2SEric W. Biederman struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user) 702bc416d97SEric Dumazet { 7031bf3751eSJohannes Berg struct iphdr iph; 7043e32e733SAlexander Drozdov int netoff; 705bc416d97SEric Dumazet u32 len; 706bc416d97SEric Dumazet 707bc416d97SEric Dumazet if (skb->protocol != htons(ETH_P_IP)) 708bc416d97SEric Dumazet return skb; 709bc416d97SEric Dumazet 7103e32e733SAlexander Drozdov netoff = skb_network_offset(skb); 7113e32e733SAlexander Drozdov 7123e32e733SAlexander Drozdov if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0) 713bc416d97SEric Dumazet return skb; 714bc416d97SEric Dumazet 7151bf3751eSJohannes Berg if (iph.ihl < 5 || iph.version != 4) 716bc416d97SEric Dumazet return skb; 717bc416d97SEric Dumazet 7181bf3751eSJohannes Berg len = ntohs(iph.tot_len); 7193e32e733SAlexander Drozdov if (skb->len < netoff + len || len < (iph.ihl * 4)) 7201bf3751eSJohannes Berg return skb; 7211bf3751eSJohannes Berg 7221bf3751eSJohannes Berg if (ip_is_fragment(&iph)) { 723bc416d97SEric Dumazet skb = skb_share_check(skb, GFP_ATOMIC); 724bc416d97SEric Dumazet if (skb) { 725*7de414a9SCong Wang if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) { 726*7de414a9SCong Wang kfree_skb(skb); 727*7de414a9SCong Wang return NULL; 728*7de414a9SCong Wang } 729*7de414a9SCong Wang if (pskb_trim_rcsum(skb, netoff + len)) { 730*7de414a9SCong Wang kfree_skb(skb); 731*7de414a9SCong Wang return NULL; 732*7de414a9SCong Wang } 733bc416d97SEric Dumazet memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 73419bcf9f2SEric W. Biederman if (ip_defrag(net, skb, user)) 735bc416d97SEric Dumazet return NULL; 7367539fadcSTom Herbert skb_clear_hash(skb); 737bc416d97SEric Dumazet } 738bc416d97SEric Dumazet } 739bc416d97SEric Dumazet return skb; 740bc416d97SEric Dumazet } 741bc416d97SEric Dumazet EXPORT_SYMBOL(ip_check_defrag); 742bc416d97SEric Dumazet 743353c9cb3SPeter Oskolkov unsigned int inet_frag_rbtree_purge(struct rb_root *root) 744353c9cb3SPeter Oskolkov { 745353c9cb3SPeter Oskolkov struct rb_node *p = rb_first(root); 746353c9cb3SPeter Oskolkov unsigned int sum = 0; 747353c9cb3SPeter Oskolkov 748353c9cb3SPeter Oskolkov while (p) { 749353c9cb3SPeter Oskolkov struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode); 750353c9cb3SPeter Oskolkov 751353c9cb3SPeter Oskolkov p = rb_next(p); 752353c9cb3SPeter Oskolkov rb_erase(&skb->rbnode, root); 753353c9cb3SPeter Oskolkov while (skb) { 754353c9cb3SPeter Oskolkov struct sk_buff *next = FRAG_CB(skb)->next_frag; 755353c9cb3SPeter Oskolkov 756353c9cb3SPeter Oskolkov sum += skb->truesize; 757353c9cb3SPeter Oskolkov kfree_skb(skb); 758353c9cb3SPeter Oskolkov skb = next; 759353c9cb3SPeter Oskolkov } 760353c9cb3SPeter Oskolkov } 761353c9cb3SPeter Oskolkov return sum; 762353c9cb3SPeter Oskolkov } 763353c9cb3SPeter Oskolkov EXPORT_SYMBOL(inet_frag_rbtree_purge); 764353c9cb3SPeter Oskolkov 7658d8354d2SPavel Emelyanov #ifdef CONFIG_SYSCTL 7663d234012SEric Dumazet static int dist_min; 7678d8354d2SPavel Emelyanov 7680a64b4b8SPavel Emelyanov static struct ctl_table ip4_frags_ns_ctl_table[] = { 7698d8354d2SPavel Emelyanov { 7708d8354d2SPavel Emelyanov .procname = "ipfrag_high_thresh", 771e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.high_thresh, 7723e67f106SEric Dumazet .maxlen = sizeof(unsigned long), 7738d8354d2SPavel Emelyanov .mode = 0644, 7743e67f106SEric Dumazet .proc_handler = proc_doulongvec_minmax, 7751bab4c75SNikolay Aleksandrov .extra1 = &init_net.ipv4.frags.low_thresh 7768d8354d2SPavel Emelyanov }, 7778d8354d2SPavel Emelyanov { 7788d8354d2SPavel Emelyanov .procname = "ipfrag_low_thresh", 779e31e0bdcSPavel Emelyanov .data = &init_net.ipv4.frags.low_thresh, 7803e67f106SEric Dumazet .maxlen = sizeof(unsigned long), 7818d8354d2SPavel Emelyanov .mode = 0644, 7823e67f106SEric Dumazet .proc_handler = proc_doulongvec_minmax, 7831bab4c75SNikolay Aleksandrov .extra2 = &init_net.ipv4.frags.high_thresh 7848d8354d2SPavel Emelyanov }, 7858d8354d2SPavel Emelyanov { 7868d8354d2SPavel Emelyanov .procname = "ipfrag_time", 787b2fd5321SPavel Emelyanov .data = &init_net.ipv4.frags.timeout, 7888d8354d2SPavel Emelyanov .maxlen = sizeof(int), 7898d8354d2SPavel Emelyanov .mode = 0644, 7906d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 7918d8354d2SPavel Emelyanov }, 7920fbf4cb2SNikolay Borisov { 7930fbf4cb2SNikolay Borisov .procname = "ipfrag_max_dist", 7940fbf4cb2SNikolay Borisov .data = &init_net.ipv4.frags.max_dist, 7950fbf4cb2SNikolay Borisov .maxlen = sizeof(int), 7960fbf4cb2SNikolay Borisov .mode = 0644, 7970fbf4cb2SNikolay Borisov .proc_handler = proc_dointvec_minmax, 7983d234012SEric Dumazet .extra1 = &dist_min, 7990fbf4cb2SNikolay Borisov }, 8007d291ebbSPavel Emelyanov { } 8017d291ebbSPavel Emelyanov }; 8027d291ebbSPavel Emelyanov 803e3a57d18SFlorian Westphal /* secret interval has been deprecated */ 804e3a57d18SFlorian Westphal static int ip4_frags_secret_interval_unused; 8057d291ebbSPavel Emelyanov static struct ctl_table ip4_frags_ctl_table[] = { 8068d8354d2SPavel Emelyanov { 8078d8354d2SPavel Emelyanov .procname = "ipfrag_secret_interval", 808e3a57d18SFlorian Westphal .data = &ip4_frags_secret_interval_unused, 8098d8354d2SPavel Emelyanov .maxlen = sizeof(int), 8108d8354d2SPavel Emelyanov .mode = 0644, 8116d9f239aSAlexey Dobriyan .proc_handler = proc_dointvec_jiffies, 8128d8354d2SPavel Emelyanov }, 8138d8354d2SPavel Emelyanov { } 8148d8354d2SPavel Emelyanov }; 8158d8354d2SPavel Emelyanov 8162c8c1e72SAlexey Dobriyan static int __net_init ip4_frags_ns_ctl_register(struct net *net) 8178d8354d2SPavel Emelyanov { 818e4a2d5c2SPavel Emelyanov struct ctl_table *table; 8198d8354d2SPavel Emelyanov struct ctl_table_header *hdr; 8208d8354d2SPavel Emelyanov 8210a64b4b8SPavel Emelyanov table = ip4_frags_ns_ctl_table; 82209ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) { 8230a64b4b8SPavel Emelyanov table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL); 82451456b29SIan Morris if (!table) 825e4a2d5c2SPavel Emelyanov goto err_alloc; 826e4a2d5c2SPavel Emelyanov 827e31e0bdcSPavel Emelyanov table[0].data = &net->ipv4.frags.high_thresh; 8281bab4c75SNikolay Aleksandrov table[0].extra1 = &net->ipv4.frags.low_thresh; 829e31e0bdcSPavel Emelyanov table[1].data = &net->ipv4.frags.low_thresh; 8301bab4c75SNikolay Aleksandrov table[1].extra2 = &net->ipv4.frags.high_thresh; 831b2fd5321SPavel Emelyanov table[2].data = &net->ipv4.frags.timeout; 8320fbf4cb2SNikolay Borisov table[3].data = &net->ipv4.frags.max_dist; 833e4a2d5c2SPavel Emelyanov } 834e4a2d5c2SPavel Emelyanov 835ec8f23ceSEric W. Biederman hdr = register_net_sysctl(net, "net/ipv4", table); 83651456b29SIan Morris if (!hdr) 837e4a2d5c2SPavel Emelyanov goto err_reg; 838e4a2d5c2SPavel Emelyanov 839e4a2d5c2SPavel Emelyanov net->ipv4.frags_hdr = hdr; 840e4a2d5c2SPavel Emelyanov return 0; 841e4a2d5c2SPavel Emelyanov 842e4a2d5c2SPavel Emelyanov err_reg: 84309ad9bc7SOctavian Purdila if (!net_eq(net, &init_net)) 844e4a2d5c2SPavel Emelyanov kfree(table); 845e4a2d5c2SPavel Emelyanov err_alloc: 846e4a2d5c2SPavel Emelyanov return -ENOMEM; 847e4a2d5c2SPavel Emelyanov } 848e4a2d5c2SPavel Emelyanov 8492c8c1e72SAlexey Dobriyan static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net) 850e4a2d5c2SPavel Emelyanov { 851e4a2d5c2SPavel Emelyanov struct ctl_table *table; 852e4a2d5c2SPavel Emelyanov 853e4a2d5c2SPavel Emelyanov table = net->ipv4.frags_hdr->ctl_table_arg; 854e4a2d5c2SPavel Emelyanov unregister_net_sysctl_table(net->ipv4.frags_hdr); 855e4a2d5c2SPavel Emelyanov kfree(table); 8568d8354d2SPavel Emelyanov } 8577d291ebbSPavel Emelyanov 85857a02c39SFabian Frederick static void __init ip4_frags_ctl_register(void) 8597d291ebbSPavel Emelyanov { 86043444757SEric W. Biederman register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table); 8617d291ebbSPavel Emelyanov } 8628d8354d2SPavel Emelyanov #else 863aa1f731eSFabian Frederick static int ip4_frags_ns_ctl_register(struct net *net) 8648d8354d2SPavel Emelyanov { 8658d8354d2SPavel Emelyanov return 0; 8668d8354d2SPavel Emelyanov } 867e4a2d5c2SPavel Emelyanov 868aa1f731eSFabian Frederick static void ip4_frags_ns_ctl_unregister(struct net *net) 869e4a2d5c2SPavel Emelyanov { 870e4a2d5c2SPavel Emelyanov } 8717d291ebbSPavel Emelyanov 872aa1f731eSFabian Frederick static void __init ip4_frags_ctl_register(void) 8737d291ebbSPavel Emelyanov { 8747d291ebbSPavel Emelyanov } 8758d8354d2SPavel Emelyanov #endif 8768d8354d2SPavel Emelyanov 8772c8c1e72SAlexey Dobriyan static int __net_init ipv4_frags_init_net(struct net *net) 8788d8354d2SPavel Emelyanov { 879787bea77SEric Dumazet int res; 880787bea77SEric Dumazet 881c2a93660SJesper Dangaard Brouer /* Fragment cache limits. 882c2a93660SJesper Dangaard Brouer * 883c2a93660SJesper Dangaard Brouer * The fragment memory accounting code, (tries to) account for 884c2a93660SJesper Dangaard Brouer * the real memory usage, by measuring both the size of frag 885c2a93660SJesper Dangaard Brouer * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) 886c2a93660SJesper Dangaard Brouer * and the SKB's truesize. 887c2a93660SJesper Dangaard Brouer * 888c2a93660SJesper Dangaard Brouer * A 64K fragment consumes 129736 bytes (44*2944)+200 889c2a93660SJesper Dangaard Brouer * (1500 truesize == 2944, sizeof(struct ipq) == 200) 890c2a93660SJesper Dangaard Brouer * 891c2a93660SJesper Dangaard Brouer * We will commit 4MB at one time. Should we cross that limit 892c2a93660SJesper Dangaard Brouer * we will prune down to 3MB, making room for approx 8 big 64K 893c2a93660SJesper Dangaard Brouer * fragments 8x128k. 894e31e0bdcSPavel Emelyanov */ 895c2a93660SJesper Dangaard Brouer net->ipv4.frags.high_thresh = 4 * 1024 * 1024; 896c2a93660SJesper Dangaard Brouer net->ipv4.frags.low_thresh = 3 * 1024 * 1024; 897e31e0bdcSPavel Emelyanov /* 898b2fd5321SPavel Emelyanov * Important NOTE! Fragment queue must be destroyed before MSL expires. 899b2fd5321SPavel Emelyanov * RFC791 is wrong proposing to prolongate timer each fragment arrival 900b2fd5321SPavel Emelyanov * by TTL. 901b2fd5321SPavel Emelyanov */ 902b2fd5321SPavel Emelyanov net->ipv4.frags.timeout = IP_FRAG_TIME; 903b2fd5321SPavel Emelyanov 9040fbf4cb2SNikolay Borisov net->ipv4.frags.max_dist = 64; 905093ba729SEric Dumazet net->ipv4.frags.f = &ip4_frags; 9060fbf4cb2SNikolay Borisov 907787bea77SEric Dumazet res = inet_frags_init_net(&net->ipv4.frags); 908787bea77SEric Dumazet if (res < 0) 909787bea77SEric Dumazet return res; 910787bea77SEric Dumazet res = ip4_frags_ns_ctl_register(net); 911787bea77SEric Dumazet if (res < 0) 912093ba729SEric Dumazet inet_frags_exit_net(&net->ipv4.frags); 913787bea77SEric Dumazet return res; 9148d8354d2SPavel Emelyanov } 9158d8354d2SPavel Emelyanov 9162c8c1e72SAlexey Dobriyan static void __net_exit ipv4_frags_exit_net(struct net *net) 91781566e83SPavel Emelyanov { 9180a64b4b8SPavel Emelyanov ip4_frags_ns_ctl_unregister(net); 919093ba729SEric Dumazet inet_frags_exit_net(&net->ipv4.frags); 92081566e83SPavel Emelyanov } 92181566e83SPavel Emelyanov 92281566e83SPavel Emelyanov static struct pernet_operations ip4_frags_ops = { 92381566e83SPavel Emelyanov .init = ipv4_frags_init_net, 92481566e83SPavel Emelyanov .exit = ipv4_frags_exit_net, 92581566e83SPavel Emelyanov }; 92681566e83SPavel Emelyanov 927648700f7SEric Dumazet 928648700f7SEric Dumazet static u32 ip4_key_hashfn(const void *data, u32 len, u32 seed) 929648700f7SEric Dumazet { 930648700f7SEric Dumazet return jhash2(data, 931648700f7SEric Dumazet sizeof(struct frag_v4_compare_key) / sizeof(u32), seed); 932648700f7SEric Dumazet } 933648700f7SEric Dumazet 934648700f7SEric Dumazet static u32 ip4_obj_hashfn(const void *data, u32 len, u32 seed) 935648700f7SEric Dumazet { 936648700f7SEric Dumazet const struct inet_frag_queue *fq = data; 937648700f7SEric Dumazet 938648700f7SEric Dumazet return jhash2((const u32 *)&fq->key.v4, 939648700f7SEric Dumazet sizeof(struct frag_v4_compare_key) / sizeof(u32), seed); 940648700f7SEric Dumazet } 941648700f7SEric Dumazet 942648700f7SEric Dumazet static int ip4_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr) 943648700f7SEric Dumazet { 944648700f7SEric Dumazet const struct frag_v4_compare_key *key = arg->key; 945648700f7SEric Dumazet const struct inet_frag_queue *fq = ptr; 946648700f7SEric Dumazet 947648700f7SEric Dumazet return !!memcmp(&fq->key, key, sizeof(*key)); 948648700f7SEric Dumazet } 949648700f7SEric Dumazet 950648700f7SEric Dumazet static const struct rhashtable_params ip4_rhash_params = { 951648700f7SEric Dumazet .head_offset = offsetof(struct inet_frag_queue, node), 952648700f7SEric Dumazet .key_offset = offsetof(struct inet_frag_queue, key), 953648700f7SEric Dumazet .key_len = sizeof(struct frag_v4_compare_key), 954648700f7SEric Dumazet .hashfn = ip4_key_hashfn, 955648700f7SEric Dumazet .obj_hashfn = ip4_obj_hashfn, 956648700f7SEric Dumazet .obj_cmpfn = ip4_obj_cmpfn, 957648700f7SEric Dumazet .automatic_shrinking = true, 958648700f7SEric Dumazet }; 959648700f7SEric Dumazet 960b7aa0bf7SEric Dumazet void __init ipfrag_init(void) 9611da177e4SLinus Torvalds { 962c6fda282SPavel Emelyanov ip4_frags.constructor = ip4_frag_init; 9631e4b8287SPavel Emelyanov ip4_frags.destructor = ip4_frag_free; 9641e4b8287SPavel Emelyanov ip4_frags.qsize = sizeof(struct ipq); 965e521db9dSPavel Emelyanov ip4_frags.frag_expire = ip_expire; 966d4ad4d22SNikolay Aleksandrov ip4_frags.frags_cache_name = ip_frag_cache_name; 967648700f7SEric Dumazet ip4_frags.rhash_params = ip4_rhash_params; 968d4ad4d22SNikolay Aleksandrov if (inet_frags_init(&ip4_frags)) 969d4ad4d22SNikolay Aleksandrov panic("IP: failed to allocate ip4_frags cache\n"); 970483a6e4fSEric Dumazet ip4_frags_ctl_register(); 971483a6e4fSEric Dumazet register_pernet_subsys(&ip4_frags_ops); 9721da177e4SLinus Torvalds } 973