diff options
Diffstat (limited to 'net/ipv4/inetpeer.c')
| -rw-r--r-- | net/ipv4/inetpeer.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index b6513b13d72..709fbb4132d 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -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); |