diff options
Diffstat (limited to 'net/ipv4/ip_fragment.c')
| -rw-r--r-- | net/ipv4/ip_fragment.c | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index f066e6073..29747fee6 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -5,7 +5,7 @@ * * The IP fragmentation functionality. * - * Version: $Id: ip_fragment.c,v 1.40 1999/03/20 23:58:34 davem Exp $ + * Version: $Id: ip_fragment.c,v 1.41 1999/05/27 00:38:07 davem Exp $ * * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG> * Alan Cox <Alan.Cox@linux.org> @@ -71,7 +71,8 @@ struct ipq { #define IPQ_HASHSZ 64 -struct ipq *ipq_hash[IPQ_HASHSZ]; +static struct ipq *ipq_hash[IPQ_HASHSZ]; +static spinlock_t ipfrag_lock = SPIN_LOCK_UNLOCKED; #define ipqhashfn(id, saddr, daddr, prot) \ ((((id) >> 1) ^ (saddr) ^ (daddr) ^ (prot)) & (IPQ_HASHSZ - 1)) @@ -141,7 +142,9 @@ static inline struct ipq *ip_find(struct iphdr *iph, struct dst_entry *dst) unsigned int hash = ipqhashfn(id, saddr, daddr, protocol); struct ipq *qp; - /* Always, we are in a BH context, so no locking. -DaveM */ + /* We are always in BH context, and protected by the + * ipfrag lock. + */ for(qp = ipq_hash[hash]; qp; qp = qp->next) { if(qp->iph->id == id && qp->iph->saddr == saddr && @@ -158,8 +161,9 @@ static inline struct ipq *ip_find(struct iphdr *iph, struct dst_entry *dst) * because we completed, reassembled and processed it, or because * it timed out. * - * This is called _only_ from BH contexts, on packet reception - * processing and from frag queue expiration timers. -DaveM + * This is called _only_ from BH contexts with the ipfrag lock held, + * on packet reception processing and from frag queue expiration + * timers. -DaveM */ static void ip_free(struct ipq *qp) { @@ -197,6 +201,7 @@ static void ip_expire(unsigned long arg) { struct ipq *qp = (struct ipq *) arg; + spin_lock(&ipfrag_lock); if(!qp->fragments) { #ifdef IP_EXPIRE_DEBUG @@ -213,10 +218,13 @@ static void ip_expire(unsigned long arg) out: /* Nuke the fragment queue. */ ip_free(qp); + spin_lock(&ipfrag_lock); } /* Memory limiting on fragments. Evictor trashes the oldest * fragment queue until we are back under the low threshold. + * + * We are always called in BH with the ipfrag lock held. */ static void ip_evictor(void) { @@ -229,9 +237,6 @@ restart: struct ipq *qp; if (atomic_read(&ip_frag_mem) <= sysctl_ipfrag_low_thresh) return; - /* We are in a BH context, so these queue - * accesses are safe. -DaveM - */ qp = ipq_hash[i]; if (qp) { /* find the oldest queue for this hash bucket */ @@ -283,7 +288,7 @@ static struct ipq *ip_create(struct sk_buff *skb, struct iphdr *iph) /* Add this entry to the queue. */ hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol); - /* We are in a BH context, no locking necessary. -DaveM */ + /* In a BH context and ipfrag lock is held. -DaveM */ if((qp->next = ipq_hash[hash]) != NULL) qp->next->pprev = &qp->next; ipq_hash[hash] = qp; @@ -421,6 +426,8 @@ struct sk_buff *ip_defrag(struct sk_buff *skb) ip_statistics.IpReasmReqds++; + spin_lock(&ipfrag_lock); + /* Start by cleaning up the memory. */ if (atomic_read(&ip_frag_mem) > sysctl_ipfrag_high_thresh) ip_evictor(); @@ -565,6 +572,7 @@ struct sk_buff *ip_defrag(struct sk_buff *skb) out_freequeue: ip_free(qp); out_skb: + spin_unlock(&ipfrag_lock); return skb; } @@ -574,6 +582,7 @@ out_skb: out_timer: mod_timer(&qp->timer, jiffies + sysctl_ipfrag_time); /* ~ 30 seconds */ out: + spin_unlock(&ipfrag_lock); return NULL; /* |