diff options
| author | Hannes Frederic Sowa <hannes@stressinduktion.org> | 2013-12-14 05:13:45 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-12-18 16:58:20 -0500 |
| commit | cd174e67a6b312fce9bab502ba2b0583e11f537f (patch) | |
| tree | 992dc562f0562abdf9d549c1d06725f001270570 | |
| parent | 974eda11c54290a1be8f8b155edae7d791e5ce57 (diff) | |
ipv4: new ip_no_pmtu_disc mode to always discard incoming frag needed msgs
This new mode discards all incoming fragmentation-needed notifications
as I guess was originally intended with this knob. To not break backward
compatibility too much, I only added a special case for mode 2 in the
receiving path.
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 10 | ||||
| -rw-r--r-- | net/ipv4/icmp.c | 4 |
2 files changed, 11 insertions, 3 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index f76d177895d9..d71afa8bd828 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -15,12 +15,18 @@ ip_default_ttl - INTEGER forwarded) IP packets. Should be between 1 and 255 inclusive. Default: 64 (as recommended by RFC1700) -ip_no_pmtu_disc - BOOLEAN - Disable Path MTU Discovery. If enabled and a +ip_no_pmtu_disc - INTEGER + Disable Path MTU Discovery. If enabled in mode 1 and a fragmentation-required ICMP is received, the PMTU to this destination will be set to min_pmtu (see below). You will need to raise min_pmtu to the smallest interface MTU on your system manually if you want to avoid locally generated fragments. + + In mode 2 incoming Path MTU Discovery messages will be + discarded. Outgoing frames are handled the same as in mode 1, + implicitly setting IP_PMTUDISC_DONT on every created socket. + + Possible values: 0-2 Default: FALSE min_pmtu - INTEGER diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 1a4ee84ca3f3..fb3c5637199d 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -705,7 +705,9 @@ static void icmp_unreach(struct sk_buff *skb) case ICMP_PORT_UNREACH: break; case ICMP_FRAG_NEEDED: - if (net->ipv4.sysctl_ip_no_pmtu_disc) { + if (net->ipv4.sysctl_ip_no_pmtu_disc == 2) { + goto out; + } else if (net->ipv4.sysctl_ip_no_pmtu_disc) { LIMIT_NETDEBUG(KERN_INFO pr_fmt("%pI4: fragmentation needed and DF set\n"), &iph->daddr); } else { |