| Message ID | 20131214041345.GO23247@order.stressinduktion.org |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Hannes Frederic Sowa <hannes@stressinduktion.org> Date: Sat, 14 Dec 2013 05:13:45 +0100 > I am sorry to create a merge conflict if the patch "ipv4: improve > documentation of ip_no_pmtu_disc" gets applied to net first. David, can you > handle that or can I help somehow? Don't worry, I'll sort this out. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Hannes Frederic Sowa <hannes@stressinduktion.org> Date: Sat, 14 Dec 2013 05:13:45 +0100 > 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> Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index f76d177..d71afa8 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 1a4ee84..fb3c563 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 {
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> --- I am sorry to create a merge conflict if the patch "ipv4: improve documentation of ip_no_pmtu_disc" gets applied to net first. David, can you handle that or can I help somehow? Documentation/networking/ip-sysctl.txt | 10 ++++++++-- net/ipv4/icmp.c | 4 +++- 2 files changed, 11 insertions(+), 3 deletions(-)