MFC r336195: unbreak dhclient(8) option 26 processing

Make dhclient(8) verify if new MTU (option 26) differs from current one
  and skip unneeded MTU change. This check eliminates infinite loop
  of MTU change / link flap / lease verification / MTU change / link flap etc.
  in case of some NIC drivers like em(4) or igb(4).

PR:		229432
Approved by:	mav (mentor)
This commit is contained in:
eugen 2018-07-18 01:57:13 +00:00 committed by Franco Fichtner
parent 700c1a0421
commit 4ab5484a83
1 changed files with 15 additions and 3 deletions

View File

@ -559,17 +559,29 @@ interface_set_mtu_priv(char *ifname, u_int16_t mtu)
{
struct ifreq ifr;
int sock;
u_int16_t old_mtu;
if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
error("Can't create socket");
memset(&ifr, 0, sizeof(ifr));
old_mtu = 0;
strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
ifr.ifr_mtu = mtu;
if (ioctl(sock, SIOCSIFMTU, &ifr) == -1)
warning("SIOCSIFMTU failed (%d): %s", mtu,
if (ioctl(sock, SIOCGIFMTU, (caddr_t)&ifr) == -1)
warning("SIOCGIFMTU failed (%s): %s", ifname,
strerror(errno));
else
old_mtu = ifr.ifr_mtu;
if (mtu != old_mtu) {
ifr.ifr_mtu = mtu;
if (ioctl(sock, SIOCSIFMTU, &ifr) == -1)
warning("SIOCSIFMTU failed (%d): %s", mtu,
strerror(errno));
}
close(sock);
}