diff options
Diffstat (limited to 'net/ipv4/ip_fragment.c')
| -rw-r--r-- | net/ipv4/ip_fragment.c | 68 |
1 files changed, 67 insertions, 1 deletions
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index 8ce0ce2ee48..ce2b70ce401 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 <linux/compiler.h> #include <linux/config.h> #include <linux/module.h> #include <linux/types.h> @@ -38,6 +39,7 @@ #include <net/ip.h> #include <net/icmp.h> #include <net/checksum.h> +#include <net/inetpeer.h> #include <linux/tcp.h> #include <linux/udp.h> #include <linux/inet.h> @@ -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. */ @@ -89,8 +93,10 @@ struct ipq { spinlock_t lock; atomic_t refcnt; struct timer_list timer; /* when will this queue expire? */ - int iif; struct timeval stamp; + int iif; + unsigned int rid; + struct inet_peer *peer; }; /* Hash table. */ @@ -195,6 +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) { @@ -353,6 +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); @@ -398,6 +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) { @@ -408,6 +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; |