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Add a sysctl to control the generation of source quench packets,

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and set it to 0 by default.

Partially obtained from:	NetBSD
Suggested by:	David Gilbert
MFC after:	5 days
This commit is contained in:
Mike Silbersack 2002-11-19 17:06:06 +00:00
parent e5562bee60
commit df285b3d1d
1 changed files with 20 additions and 2 deletions
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18
sys/netinet/ip_input.c
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@ -125,6 +125,11 @@ SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW,
&ip_maxfragpackets, 0,
"Maximum number of IPv4 fragment reassembly queue entries");
static int ip_sendsourcequench = 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
&ip_sendsourcequench, 0,
"Enable the transmission of source quench packets");
/*
* XXX - Setting ip_checkinterface mostly implements the receive side of
* the Strong ES model described in RFC 1122, but since the routing table
@ -1971,8 +1976,21 @@ ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
break;
case ENOBUFS:
/*
* A router should not generate ICMP_SOURCEQUENCH as
* required in RFC1812 Requirements for IP Version 4 Routers.
* Source quench could be a big problem under DoS attacks,
* or if the underlying interface is rate-limited.
* Those who need source quench packets may re-enable them
* via the net.inet.ip.sendsourcequench sysctl.
*/
if (ip_sendsourcequench == 0) {
m_freem(mcopy);
return;
} else {
type = ICMP_SOURCEQUENCH;
code = 0;
}
break;
case EACCES: /* ipfw denied packet */