From 221e5d2dd5844c901a7b23d422207b737742f566 Mon Sep 17 00:00:00 2001 From: Maxim Sobolev Date: Sat, 23 Feb 2019 23:31:13 +0000 Subject: [PATCH] Further refine r336195: do not even attempt to verify/update interface's MTU if we've set it once and there were no changes on the DHCP server side since the last refresh. This is consistent I believe with how dhclient handles other settings like IP address, mask etc. Approved by: cem, eugen Differential Revision: https://reviews.freebsd.org/D18546 --- sbin/dhclient/dhclient.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c index c65ff81b5cfc..1d013ed57d7a 100644 --- a/sbin/dhclient/dhclient.c +++ b/sbin/dhclient/dhclient.c @@ -863,6 +863,7 @@ bind_lease(struct interface_info *ip) opt = &ip->client->new->options[DHO_INTERFACE_MTU]; if (opt->len == sizeof(u_int16_t)) { u_int16_t mtu = 0; + u_int16_t old_mtu = 0; bool supersede = (ip->client->config->default_actions[DHO_INTERFACE_MTU] == ACTION_SUPERSEDE); @@ -871,12 +872,19 @@ bind_lease(struct interface_info *ip) else mtu = be16dec(opt->data); + if (ip->client->active) { + opt = &ip->client->active->options[DHO_INTERFACE_MTU]; + if (opt->len == sizeof(u_int16_t)) { + old_mtu = be16dec(opt->data); + } + } + if (mtu < MIN_MTU) { /* Treat 0 like a user intentionally doesn't want to change MTU and, * therefore, warning is not needed */ if (!supersede || mtu != 0) warning("mtu size %u < %d: ignored", (unsigned)mtu, MIN_MTU); - } else { + } else if (ip->client->state != S_RENEWING || mtu != old_mtu) { interface_set_mtu_unpriv(privfd, mtu); } }