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inetpeer: Move ICMP rate limiting state into inet_peer entries. 

Like metrics, the ICMP rate limiting bits are cached state about
a destination.  So move it into the inet_peer entries.

If an inet_peer cannot be bound (the reason is memory allocation
failure or similar), the policy is to allow.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2011-02-04 15:55:25 -08:00
parent 0131ba451e
commit 92d8682926
9 changed files with 108 additions and 73 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/net/dst.h
View File

@ -78,8 +78,6 @@ struct dst_entry {
atomic_t __refcnt; /* client references */
int __use;
unsigned long lastuse;
unsigned long rate_last; /* rate limiting for ICMP */
unsigned int rate_tokens;
int flags;
#define DST_HOST 0x0001
#define DST_NOXFRM 0x0002

3
include/net/icmp.h
View File

@ -45,7 +45,4 @@ extern int icmp_ioctl(struct sock *sk, int cmd, unsigned long arg);
extern int icmp_init(void);
extern void icmp_out_count(struct net *net, unsigned char type);
/* Move into dst.h ? */
extern int xrlim_allow(struct dst_entry *dst, int timeout);
#endif /* _ICMP_H */

3
include/net/inetpeer.h
View File

@ -44,6 +44,8 @@ struct inet_peer {
__u32 tcp_ts;
__u32 tcp_ts_stamp;
u32 metrics[RTAX_MAX];
u32 rate_tokens; /* rate limiting for ICMP */
unsigned long rate_last;
};
struct rcu_head rcu;
};
@ -81,6 +83,7 @@ static inline struct inet_peer *inet_getpeer_v6(struct in6_addr *v6daddr, int cr
/* can be called from BH context or outside */
extern void inet_putpeer(struct inet_peer *p);
extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
/*
* temporary check to make sure we dont access rid, ip_id_count, tcp_ts,

49
net/ipv4/icmp.c
View File

@ -233,48 +233,11 @@ static inline void icmp_xmit_unlock(struct sock *sk)
* Send an ICMP frame.
*/
/*
* Check transmit rate limitation for given message.
* The rate information is held in the destination cache now.
* This function is generic and could be used for other purposes
* too. It uses a Token bucket filter as suggested by Alexey Kuznetsov.
*
* Note that the same dst_entry fields are modified by functions in
* route.c too, but these work for packet destinations while xrlim_allow
* works for icmp destinations. This means the rate limiting information
* for one "ip object" is shared - and these ICMPs are twice limited:
* by source and by destination.
*
* RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate
* SHOULD allow setting of rate limits
*
* Shared between ICMPv4 and ICMPv6.
*/
#define XRLIM_BURST_FACTOR 6
int xrlim_allow(struct dst_entry *dst, int timeout)
{
unsigned long now, token = dst->rate_tokens;
int rc = 0;
now = jiffies;
token += now - dst->rate_last;
dst->rate_last = now;
if (token > XRLIM_BURST_FACTOR * timeout)
token = XRLIM_BURST_FACTOR * timeout;
if (token >= timeout) {
token -= timeout;
rc = 1;
}
dst->rate_tokens = token;
return rc;
}
EXPORT_SYMBOL(xrlim_allow);
static inline int icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
static inline bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
int type, int code)
{
struct dst_entry *dst = &rt->dst;
int rc = 1;
bool rc = true;
if (type > NR_ICMP_TYPES)
goto out;
@ -288,8 +251,12 @@ static inline int icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
goto out;
/* Limit if icmp type is enabled in ratemask. */
if ((1 << type) & net->ipv4.sysctl_icmp_ratemask)
rc = xrlim_allow(dst, net->ipv4.sysctl_icmp_ratelimit);
if ((1 << type) & net->ipv4.sysctl_icmp_ratemask) {
if (!rt->peer)
rt_bind_peer(rt, 1);
rc = inet_peer_xrlim_allow(rt->peer,
net->ipv4.sysctl_icmp_ratelimit);
}
out:
return rc;
}

43
net/ipv4/inetpeer.c
View File

@ -513,6 +513,8 @@ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
atomic_set(&p->ip_id_count, secure_ip_id(daddr->a4));
p->tcp_ts_stamp = 0;
p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW;
p->rate_tokens = 0;
p->rate_last = 0;
INIT_LIST_HEAD(&p->unused);
@ -580,3 +582,44 @@ void inet_putpeer(struct inet_peer *p)
local_bh_enable();
}
EXPORT_SYMBOL_GPL(inet_putpeer);
/*
* Check transmit rate limitation for given message.
* The rate information is held in the inet_peer entries now.
* This function is generic and could be used for other purposes
* too. It uses a Token bucket filter as suggested by Alexey Kuznetsov.
*
* Note that the same inet_peer fields are modified by functions in
* route.c too, but these work for packet destinations while xrlim_allow
* works for icmp destinations. This means the rate limiting information
* for one "ip object" is shared - and these ICMPs are twice limited:
* by source and by destination.
*
* RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate
* SHOULD allow setting of rate limits
*
* Shared between ICMPv4 and ICMPv6.
*/
#define XRLIM_BURST_FACTOR 6
bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout)
{
unsigned long now, token;
bool rc = false;
if (!peer)
return true;
token = peer->rate_tokens;
now = jiffies;
token += now - peer->rate_last;
peer->rate_last = now;
if (token > XRLIM_BURST_FACTOR * timeout)
token = XRLIM_BURST_FACTOR * timeout;
if (token >= timeout) {
token -= timeout;
rc = true;
}
peer->rate_tokens = token;
return rc;
}
EXPORT_SYMBOL(inet_peer_xrlim_allow);

56
net/ipv4/route.c
View File

@ -1563,6 +1563,7 @@ void ip_rt_send_redirect(struct sk_buff *skb)
{
struct rtable *rt = skb_rtable(skb);
struct in_device *in_dev;
struct inet_peer *peer;
int log_martians;
rcu_read_lock();
@ -1574,33 +1575,41 @@ void ip_rt_send_redirect(struct sk_buff *skb)
log_martians = IN_DEV_LOG_MARTIANS(in_dev);
rcu_read_unlock();
if (!rt->peer)
rt_bind_peer(rt, 1);
peer = rt->peer;
if (!peer) {
icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
return;
}
/* No redirected packets during ip_rt_redirect_silence;
* reset the algorithm.
*/
if (time_after(jiffies, rt->dst.rate_last + ip_rt_redirect_silence))
rt->dst.rate_tokens = 0;
if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
peer->rate_tokens = 0;
/* Too many ignored redirects; do not send anything
* set dst.rate_last to the last seen redirected packet.
*/
if (rt->dst.rate_tokens >= ip_rt_redirect_number) {
rt->dst.rate_last = jiffies;
if (peer->rate_tokens >= ip_rt_redirect_number) {
peer->rate_last = jiffies;
return;
}
/* Check for load limit; set rate_last to the latest sent
* redirect.
*/
if (rt->dst.rate_tokens == 0 ||
if (peer->rate_tokens == 0 ||
time_after(jiffies,
(rt->dst.rate_last +
(ip_rt_redirect_load << rt->dst.rate_tokens)))) {
(peer->rate_last +
(ip_rt_redirect_load << peer->rate_tokens)))) {
icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
rt->dst.rate_last = jiffies;
++rt->dst.rate_tokens;
peer->rate_last = jiffies;
++peer->rate_tokens;
#ifdef CONFIG_IP_ROUTE_VERBOSE
if (log_martians &&
rt->dst.rate_tokens == ip_rt_redirect_number &&
peer->rate_tokens == ip_rt_redirect_number &&
net_ratelimit())
printk(KERN_WARNING "host %pI4/if%d ignores redirects for %pI4 to %pI4.\n",
&rt->rt_src, rt->rt_iif,
@ -1612,7 +1621,9 @@ void ip_rt_send_redirect(struct sk_buff *skb)
static int ip_error(struct sk_buff *skb)
{
struct rtable *rt = skb_rtable(skb);
struct inet_peer *peer;
unsigned long now;
bool send;
int code;
switch (rt->dst.error) {
@ -1632,15 +1643,24 @@ static int ip_error(struct sk_buff *skb)
break;
}
now = jiffies;
rt->dst.rate_tokens += now - rt->dst.rate_last;
if (rt->dst.rate_tokens > ip_rt_error_burst)
rt->dst.rate_tokens = ip_rt_error_burst;
rt->dst.rate_last = now;
if (rt->dst.rate_tokens >= ip_rt_error_cost) {
rt->dst.rate_tokens -= ip_rt_error_cost;
icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
if (!rt->peer)
rt_bind_peer(rt, 1);
peer = rt->peer;
send = true;
if (peer) {
now = jiffies;
peer->rate_tokens += now - peer->rate_last;
if (peer->rate_tokens > ip_rt_error_burst)
peer->rate_tokens = ip_rt_error_burst;
peer->rate_last = now;
if (peer->rate_tokens >= ip_rt_error_cost)
peer->rate_tokens -= ip_rt_error_cost;
else
send = false;
}
if (send)
icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
out: kfree_skb(skb);
return 0;

16
net/ipv6/icmp.c
View File

@ -157,20 +157,20 @@ static int is_ineligible(struct sk_buff *skb)
/*
* Check the ICMP output rate limit
*/
static inline int icmpv6_xrlim_allow(struct sock *sk, u8 type,
struct flowi *fl)
static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
struct flowi *fl)
{
struct dst_entry *dst;
struct net *net = sock_net(sk);
int res = 0;
bool res = false;
/* Informational messages are not limited. */
if (type & ICMPV6_INFOMSG_MASK)
return 1;
return true;
/* Do not limit pmtu discovery, it would break it. */
if (type == ICMPV6_PKT_TOOBIG)
return 1;
return true;
/*
* Look up the output route.
@ -182,7 +182,7 @@ static inline int icmpv6_xrlim_allow(struct sock *sk, u8 type,
IP6_INC_STATS(net, ip6_dst_idev(dst),
IPSTATS_MIB_OUTNOROUTES);
} else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
res = 1;
res = true;
} else {
struct rt6_info *rt = (struct rt6_info *)dst;
int tmo = net->ipv6.sysctl.icmpv6_time;
@ -191,7 +191,9 @@ static inline int icmpv6_xrlim_allow(struct sock *sk, u8 type,
if (rt->rt6i_dst.plen < 128)
tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
res = xrlim_allow(dst, tmo);
if (!rt->rt6i_peer)
rt6_bind_peer(rt, 1);
res = inet_peer_xrlim_allow(rt->rt6i_peer, tmo);
}
dst_release(dst);
return res;

5
net/ipv6/ip6_output.c
View File

@ -479,10 +479,13 @@ int ip6_forward(struct sk_buff *skb)
else
target = &hdr->daddr;
if (!rt->rt6i_peer)
rt6_bind_peer(rt, 1);
/* Limit redirects both by destination (here)
and by source (inside ndisc_send_redirect)
*/
if (xrlim_allow(dst, 1*HZ))
if (inet_peer_xrlim_allow(rt->rt6i_peer, 1*HZ))
ndisc_send_redirect(skb, n, target);
} else {
int addrtype = ipv6_addr_type(&hdr->saddr);

4
net/ipv6/ndisc.c
View File

@ -1553,7 +1553,9 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
"ICMPv6 Redirect: destination is not a neighbour.\n");
goto release;
}
if (!xrlim_allow(dst, 1*HZ))
if (!rt->rt6i_peer)
rt6_bind_peer(rt, 1);
if (inet_peer_xrlim_allow(rt->rt6i_peer, 1*HZ))
goto release;
if (dev->addr_len) {