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authorGuillaume Nault2018-08-03 12:38:39 +0200
committerDavid S. Miller2018-08-03 19:03:57 +0200
commite9697e2effad50c0081b3c72002d3975f8ab4347 (patch)
treeffa8f583cf4fedb528944b3b1121a1471bd7f6eb /include/uapi/linux/l2tp.h
parentl2tp: simplify MTU handling in l2tp_ppp (diff)
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l2tp: ignore L2TP_ATTR_MTU
This attribute's handling is broken. It can only be used when creating Ethernet pseudo-wires, in which case its value can be used as the initial MTU for the l2tpeth device. However, when handling update requests, L2TP_ATTR_MTU only modifies session->mtu. This value is never propagated to the l2tpeth device. Dump requests also return the value of session->mtu, which is not synchronised anymore with the device MTU. The same problem occurs if the device MTU is properly updated using the generic IFLA_MTU attribute. In this case, session->mtu is not updated, and L2TP_ATTR_MTU will report an invalid value again when dumping the session. It does not seem worthwhile to complexify l2tp_eth.c to synchronise session->mtu with the device MTU. Even the ip-l2tp manpage advises to use 'ip link' to initialise the MTU of l2tpeth devices (iproute2 does not handle L2TP_ATTR_MTU at all anyway). So let's just ignore it entirely. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/uapi/linux/l2tp.h')
-rw-r--r--include/uapi/linux/l2tp.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/uapi/linux/l2tp.h b/include/uapi/linux/l2tp.h
index 8bb8c7cfabe5..61158f5a1a5b 100644
--- a/include/uapi/linux/l2tp.h
+++ b/include/uapi/linux/l2tp.h
@@ -119,7 +119,7 @@ enum {
L2TP_ATTR_IP_DADDR, /* u32 */
L2TP_ATTR_UDP_SPORT, /* u16 */
L2TP_ATTR_UDP_DPORT, /* u16 */
- L2TP_ATTR_MTU, /* u16 */
+ L2TP_ATTR_MTU, /* u16 (not used) */
L2TP_ATTR_MRU, /* u16 (not used) */
L2TP_ATTR_STATS, /* nested */
L2TP_ATTR_IP6_SADDR, /* struct in6_addr */