fdo-mirrors/NetworkManager
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/NetworkManager/NetworkManager.git synced 2026-01-16 12:21:37 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

l3cfg: fix CLAT MTU handling

Browse source 
The current code takes the IPv6 MTU value from the IPv6 default
route. However, that value is always zero because NM doesn't set it
usually. Instead, it should use the IPv6 MTU sysctl value. The problem
is that at this point NM hasn't written the sysctl yet, and we need
some logic to find the actual value.
This commit is contained in:
Beniamino Galvani 2026-01-14 08:40:44 +01:00
parent 22a9493f07
commit 7d284c5fa7
1 changed files with 26 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

32
src/core/nm-l3cfg.c
View file

@ -4361,7 +4361,6 @@ _l3cfg_update_combined_config(NML3Cfg *self,
nm_l3_config_data_get_best_default_route(l3cd, AF_INET6));
}
if (best_v6_route) {
int mtu;
NMPlatformIP4Address addr = {
.ifindex = self->priv.ifindex,
.address = self->priv.p->clat_address_4->addr,
@ -4369,18 +4368,39 @@ _l3cfg_update_combined_config(NML3Cfg *self,
.addr_source = NM_IP_CONFIG_SOURCE_CLAT,
.plen = 32,
};
const NMPlatformLink *pllink;
guint mtu = 0;
guint val = 0;
best_v6_gateway.addr_family = AF_INET6;
best_v6_gateway.addr.addr6 = best_v6_route->gateway;
mtu = best_v6_route->mtu;
/* Determine the IPv6 MTU of the interface. Unfortunately,
* the logic to set the MTU is in NMDevice and here we need
* some duplication to find the actual value.
* TODO: move the MTU handling into l3cfg. */
if (!mtu || mtu > 1500) {
/* v4 Internet MTU */
/* Get the link MTU */
pllink = nm_l3cfg_get_pllink(self, TRUE);
if (pllink)
mtu = pllink->mtu;
if (mtu == 0)
mtu = 1500;
/* Update it with the IPv6 MTU value from the connection
* or from RA */
val = nm_l3_config_data_get_ip6_mtu_static(l3cd);
if (val == 0) {
val = nm_l3_config_data_get_ip6_mtu_ra(l3cd);
}
/* 20 for the ipv6 vs ipv4 header plus 8 for a potential
fragmentation extension header */
if (val != 0 && val < mtu) {
mtu = val;
}
if (mtu < 1280)
mtu = 1280;
/* Leave 20 additional bytes for the ipv4 -> ipv6 header translation,
* plus 8 for a potential fragmentation extension header */
mtu -= 28;
rx.r4 = (NMPlatformIP4Route) {