diff options
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 23 | ||||
| -rw-r--r-- | include/linux/sysctl.h | 1 | ||||
| -rw-r--r-- | include/net/inetpeer.h | 1 | ||||
| -rw-r--r-- | include/net/ip.h | 2 | ||||
| -rw-r--r-- | net/ipv4/inetpeer.c | 1 | ||||
| -rw-r--r-- | net/ipv4/ip_fragment.c | 68 | ||||
| -rw-r--r-- | net/ipv4/ip_output.c | 1 | ||||
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 10 |
8 files changed, 106 insertions, 1 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index ebc09a159f62..2b7cf19a06ad 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -46,6 +46,29 @@ ipfrag_secret_interval - INTEGER for the hash secret) for IP fragments. Default: 600 +ipfrag_max_dist - INTEGER + ipfrag_max_dist is a non-negative integer value which defines the + maximum "disorder" which is allowed among fragments which share a + common IP source address. Note that reordering of packets is + not unusual, but if a large number of fragments arrive from a source + IP address while a particular fragment queue remains incomplete, it + probably indicates that one or more fragments belonging to that queue + have been lost. When ipfrag_max_dist is positive, an additional check + is done on fragments before they are added to a reassembly queue - if + ipfrag_max_dist (or more) fragments have arrived from a particular IP + address between additions to any IP fragment queue using that source + address, it's presumed that one or more fragments in the queue are + lost. The existing fragment queue will be dropped, and a new one + started. An ipfrag_max_dist value of zero disables this check. + + Using a very small value, e.g. 1 or 2, for ipfrag_max_dist can + result in unnecessarily dropping fragment queues when normal + reordering of packets occurs, which could lead to poor application + performance. Using a very large value, e.g. 50000, increases the + likelihood of incorrectly reassembling IP fragments that originate + from different IP datagrams, which could result in data corruption. + Default: 64 + INET peer storage: inet_peer_threshold - INTEGER diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 4be34ef8c2f7..93fa765e47d3 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -390,6 +390,7 @@ enum NET_IPV4_ICMP_ERRORS_USE_INBOUND_IFADDR=109, NET_TCP_CONG_CONTROL=110, NET_TCP_ABC=111, + NET_IPV4_IPFRAG_MAX_DIST=112, }; enum { diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h index 7fda471002b6..0965515f40cf 100644 --- a/include/net/inetpeer.h +++ b/include/net/inetpeer.h @@ -25,6 +25,7 @@ struct inet_peer __u32 v4daddr; /* peer's address */ __u16 avl_height; __u16 ip_id_count; /* IP ID for the next packet */ + atomic_t rid; /* Frag reception counter */ __u32 tcp_ts; unsigned long tcp_ts_stamp; }; diff --git a/include/net/ip.h b/include/net/ip.h index e4563bbee6ea..4d6294ba038e 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -45,6 +45,7 @@ struct inet_skb_parm #define IPSKB_TRANSLATED 2 #define IPSKB_FORWARDED 4 #define IPSKB_XFRM_TUNNEL_SIZE 8 +#define IPSKB_FRAG_COMPLETE 16 }; struct ipcm_cookie @@ -168,6 +169,7 @@ extern int sysctl_ipfrag_high_thresh; extern int sysctl_ipfrag_low_thresh; extern int sysctl_ipfrag_time; extern int sysctl_ipfrag_secret_interval; +extern int sysctl_ipfrag_max_dist; /* From inetpeer.c */ extern int inet_peer_threshold; diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index 2fc3fd38924f..ce5fe3f74a3d 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -401,6 +401,7 @@ struct inet_peer *inet_getpeer(__u32 daddr, int create) return NULL; n->v4daddr = daddr; atomic_set(&n->refcnt, 1); + atomic_set(&n->rid, 0); n->ip_id_count = secure_ip_id(daddr); n->tcp_ts_stamp = 0; diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index 8ce0ce2ee48e..ce2b70ce4018 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; diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index eba64e2bd397..2a830de3a699 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -445,6 +445,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)) hlen = iph->ihl * 4; mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */ + IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE; /* When frag_list is given, use it. First, check its validity: * some transformers could create wrong frag_list or break existing diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 01444a02b48b..dbf82955aabe 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -22,6 +22,7 @@ extern int sysctl_ip_nonlocal_bind; #ifdef CONFIG_SYSCTL +static int zero; static int tcp_retr1_max = 255; static int ip_local_port_range_min[] = { 1, 1 }; static int ip_local_port_range_max[] = { 65535, 65535 }; @@ -614,6 +615,15 @@ ctl_table ipv4_table[] = { .strategy = &sysctl_jiffies }, { + .ctl_name = NET_IPV4_IPFRAG_MAX_DIST, + .procname = "ipfrag_max_dist", + .data = &sysctl_ipfrag_max_dist, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .extra1 = &zero + }, + { .ctl_name = NET_TCP_NO_METRICS_SAVE, .procname = "tcp_no_metrics_save", .data = &sysctl_tcp_nometrics_save, |