X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=net%2Fipv4%2Fip_fragment.c;h=2a8adda15e1199c3d849d4e51ad899eabfeb43c3;hb=489447380a2921ec0e9154f773c44ab3167ede4b;hp=e7d26d9943c2d5aea36b465304b8b98db12a7abd;hpb=c324b44c34050cf2a9b58830e11c974806bd85d8;p=linux-2.6 diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index e7d26d9943..2a8adda15e 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -22,6 +22,7 @@ * Patrick McHardy : LRU queue of frag heads for evictor. */ +#include #include #include #include @@ -38,6 +39,7 @@ #include #include #include +#include #include #include #include @@ -56,6 +58,8 @@ int sysctl_ipfrag_high_thresh = 256*1024; int sysctl_ipfrag_low_thresh = 192*1024; +int sysctl_ipfrag_max_dist = 64; + /* Important NOTE! Fragment queue must be destroyed before MSL expires. * RFC791 is wrong proposing to prolongate timer each fragment arrival by TTL. */ @@ -71,7 +75,7 @@ struct ipfrag_skb_cb /* Describe an entry in the "incomplete datagrams" queue. */ struct ipq { - struct ipq *next; /* linked list pointers */ + struct hlist_node list; struct list_head lru_list; /* lru list member */ u32 user; u32 saddr; @@ -89,9 +93,10 @@ struct ipq { spinlock_t lock; atomic_t refcnt; struct timer_list timer; /* when will this queue expire? */ - struct ipq **pprev; - int iif; struct timeval stamp; + int iif; + unsigned int rid; + struct inet_peer *peer; }; /* Hash table. */ @@ -99,7 +104,7 @@ struct ipq { #define IPQ_HASHSZ 64 /* Per-bucket lock is easy to add now. */ -static struct ipq *ipq_hash[IPQ_HASHSZ]; +static struct hlist_head ipq_hash[IPQ_HASHSZ]; static DEFINE_RWLOCK(ipfrag_lock); static u32 ipfrag_hash_rnd; static LIST_HEAD(ipq_lru_list); @@ -107,9 +112,7 @@ int ip_frag_nqueues = 0; static __inline__ void __ipq_unlink(struct ipq *qp) { - if(qp->next) - qp->next->pprev = qp->pprev; - *qp->pprev = qp->next; + hlist_del(&qp->list); list_del(&qp->lru_list); ip_frag_nqueues--; } @@ -139,27 +142,18 @@ static void ipfrag_secret_rebuild(unsigned long dummy) get_random_bytes(&ipfrag_hash_rnd, sizeof(u32)); for (i = 0; i < IPQ_HASHSZ; i++) { struct ipq *q; + struct hlist_node *p, *n; - q = ipq_hash[i]; - while (q) { - struct ipq *next = q->next; + hlist_for_each_entry_safe(q, p, n, &ipq_hash[i], list) { unsigned int hval = ipqhashfn(q->id, q->saddr, q->daddr, q->protocol); if (hval != i) { - /* Unlink. */ - if (q->next) - q->next->pprev = q->pprev; - *q->pprev = q->next; + hlist_del(&q->list); /* Relink to new hash chain. */ - if ((q->next = ipq_hash[hval]) != NULL) - q->next->pprev = &q->next; - ipq_hash[hval] = q; - q->pprev = &ipq_hash[hval]; + hlist_add_head(&q->list, &ipq_hash[hval]); } - - q = next; } } write_unlock(&ipfrag_lock); @@ -207,6 +201,9 @@ static void ip_frag_destroy(struct ipq *qp, int *work) BUG_TRAP(qp->last_in&COMPLETE); BUG_TRAP(del_timer(&qp->timer) == 0); + if (qp->peer) + inet_putpeer(qp->peer); + /* Release all fragment data. */ fp = qp->fragments; while (fp) { @@ -310,14 +307,16 @@ out: static struct ipq *ip_frag_intern(unsigned int hash, struct ipq *qp_in) { struct ipq *qp; - +#ifdef CONFIG_SMP + struct hlist_node *n; +#endif write_lock(&ipfrag_lock); #ifdef CONFIG_SMP /* With SMP race we have to recheck hash table, because * such entry could be created on other cpu, while we * promoted read lock to write lock. */ - for(qp = ipq_hash[hash]; qp; qp = qp->next) { + hlist_for_each_entry(qp, n, &ipq_hash[hash], list) { if(qp->id == qp_in->id && qp->saddr == qp_in->saddr && qp->daddr == qp_in->daddr && @@ -337,10 +336,7 @@ static struct ipq *ip_frag_intern(unsigned int hash, struct ipq *qp_in) atomic_inc(&qp->refcnt); atomic_inc(&qp->refcnt); - if((qp->next = ipq_hash[hash]) != NULL) - qp->next->pprev = &qp->next; - ipq_hash[hash] = qp; - qp->pprev = &ipq_hash[hash]; + hlist_add_head(&qp->list, &ipq_hash[hash]); INIT_LIST_HEAD(&qp->lru_list); list_add_tail(&qp->lru_list, &ipq_lru_list); ip_frag_nqueues++; @@ -366,6 +362,7 @@ static struct ipq *ip_frag_create(unsigned hash, struct iphdr *iph, u32 user) qp->meat = 0; qp->fragments = NULL; qp->iif = 0; + qp->peer = sysctl_ipfrag_max_dist ? inet_getpeer(iph->saddr, 1) : NULL; /* Initialize a timer for this entry. */ init_timer(&qp->timer); @@ -386,15 +383,16 @@ out_nomem: */ static inline struct ipq *ip_find(struct iphdr *iph, u32 user) { - __u16 id = iph->id; + __be16 id = iph->id; __u32 saddr = iph->saddr; __u32 daddr = iph->daddr; __u8 protocol = iph->protocol; unsigned int hash = ipqhashfn(id, saddr, daddr, protocol); struct ipq *qp; + struct hlist_node *n; read_lock(&ipfrag_lock); - for(qp = ipq_hash[hash]; qp; qp = qp->next) { + hlist_for_each_entry(qp, n, &ipq_hash[hash], list) { if(qp->id == id && qp->saddr == saddr && qp->daddr == daddr && @@ -410,6 +408,56 @@ static inline struct ipq *ip_find(struct iphdr *iph, u32 user) return ip_frag_create(hash, iph, user); } +/* Is the fragment too far ahead to be part of ipq? */ +static inline int ip_frag_too_far(struct ipq *qp) +{ + struct inet_peer *peer = qp->peer; + unsigned int max = sysctl_ipfrag_max_dist; + unsigned int start, end; + + int rc; + + if (!peer || !max) + return 0; + + start = qp->rid; + end = atomic_inc_return(&peer->rid); + qp->rid = end; + + rc = qp->fragments && (end - start) > max; + + if (rc) { + IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); + } + + return rc; +} + +static int ip_frag_reinit(struct ipq *qp) +{ + struct sk_buff *fp; + + if (!mod_timer(&qp->timer, jiffies + sysctl_ipfrag_time)) { + atomic_inc(&qp->refcnt); + return -ETIMEDOUT; + } + + fp = qp->fragments; + do { + struct sk_buff *xp = fp->next; + frag_kfree_skb(fp, NULL); + fp = xp; + } while (fp); + + qp->last_in = 0; + qp->len = 0; + qp->meat = 0; + qp->fragments = NULL; + qp->iif = 0; + + return 0; +} + /* Add new segment to existing queue. */ static void ip_frag_queue(struct ipq *qp, struct sk_buff *skb) { @@ -420,6 +468,12 @@ static void ip_frag_queue(struct ipq *qp, struct sk_buff *skb) if (qp->last_in & COMPLETE) goto err; + if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && + unlikely(ip_frag_too_far(qp)) && unlikely(ip_frag_reinit(qp))) { + ipq_kill(qp); + goto err; + } + offset = ntohs(skb->nh.iph->frag_off); flags = offset & ~IP_OFFSET; offset &= IP_OFFSET;