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icmp: move icmp_global.credit and icmp_global.stamp to per netns storage

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Host wide ICMP ratelimiter should be per netns, to provide better isolation.

Following patch in this series makes the sysctl per netns.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20240829144641.3880376-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2024-08-29 14:46:40 +00:00 committed by Jakub Kicinski
parent 8c2bd38b95
commit b056b4cd91
4 changed files with 17 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/net/ip.h
View File

@ -794,8 +794,8 @@ static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
}
bool icmp_global_allow(void);
void icmp_global_consume(void);
bool icmp_global_allow(struct net *net);
void icmp_global_consume(struct net *net);
extern int sysctl_icmp_msgs_per_sec;
extern int sysctl_icmp_msgs_burst;

3
include/net/netns/ipv4.h
View File

@ -122,7 +122,8 @@ struct netns_ipv4 {
u8 sysctl_icmp_errors_use_inbound_ifaddr;
int sysctl_icmp_ratelimit;
int sysctl_icmp_ratemask;
atomic_t icmp_global_credit;
u32 icmp_global_stamp;
u32 ip_rt_min_pmtu;
int ip_rt_mtu_expires;
int ip_rt_min_advmss;

26
net/ipv4/icmp.c
View File

@ -223,19 +223,15 @@ static inline void icmp_xmit_unlock(struct sock *sk)
int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
int sysctl_icmp_msgs_burst __read_mostly = 50;
static struct {
atomic_t credit;
u32 stamp;
} icmp_global;
/**
* icmp_global_allow - Are we allowed to send one more ICMP message ?
* @net: network namespace
*
* Uses a token bucket to limit our ICMP messages to ~sysctl_icmp_msgs_per_sec.
* Returns false if we reached the limit and can not send another packet.
* Works in tandem with icmp_global_consume().
*/
bool icmp_global_allow(void)
bool icmp_global_allow(struct net *net)
{
u32 delta, now, oldstamp;
int incr, new, old;
@ -244,11 +240,11 @@ bool icmp_global_allow(void)
* Then later icmp_global_consume() could consume more credits,
* this is an acceptable race.
*/
if (atomic_read(&icmp_global.credit) > 0)
if (atomic_read(&net->ipv4.icmp_global_credit) > 0)
return true;
now = jiffies;
oldstamp = READ_ONCE(icmp_global.stamp);
oldstamp = READ_ONCE(net->ipv4.icmp_global_stamp);
delta = min_t(u32, now - oldstamp, HZ);
if (delta < HZ / 50)
return false;
@ -257,23 +253,23 @@ bool icmp_global_allow(void)
if (!incr)
return false;
if (cmpxchg(&icmp_global.stamp, oldstamp, now) == oldstamp) {
old = atomic_read(&icmp_global.credit);
if (cmpxchg(&net->ipv4.icmp_global_stamp, oldstamp, now) == oldstamp) {
old = atomic_read(&net->ipv4.icmp_global_credit);
do {
new = min(old + incr, READ_ONCE(sysctl_icmp_msgs_burst));
} while (!atomic_try_cmpxchg(&icmp_global.credit, &old, new));
} while (!atomic_try_cmpxchg(&net->ipv4.icmp_global_credit, &old, new));
}
return true;
}
EXPORT_SYMBOL(icmp_global_allow);
void icmp_global_consume(void)
void icmp_global_consume(struct net *net)
{
int credits = get_random_u32_below(3);
/* Note: this might make icmp_global.credit negative. */
if (credits)
atomic_sub(credits, &icmp_global.credit);
atomic_sub(credits, &net->ipv4.icmp_global_credit);
}
EXPORT_SYMBOL(icmp_global_consume);
@ -299,7 +295,7 @@ static bool icmpv4_global_allow(struct net *net, int type, int code,
if (icmpv4_mask_allow(net, type, code))
return true;
if (icmp_global_allow()) {
if (icmp_global_allow(net)) {
*apply_ratelimit = true;
return true;
}
@ -337,7 +333,7 @@ out:
if (!rc)
__ICMP_INC_STATS(net, ICMP_MIB_RATELIMITHOST);
else
icmp_global_consume();
icmp_global_consume(net);
return rc;
}

4
net/ipv6/icmp.c
View File

@ -181,7 +181,7 @@ static bool icmpv6_global_allow(struct net *net, int type,
if (icmpv6_mask_allow(net, type))
return true;
if (icmp_global_allow()) {
if (icmp_global_allow(net)) {
*apply_ratelimit = true;
return true;
}
@ -231,7 +231,7 @@ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
__ICMP6_INC_STATS(net, ip6_dst_idev(dst),
ICMP6_MIB_RATELIMITHOST);
else
icmp_global_consume();
icmp_global_consume(net);
dst_release(dst);
return res;
}