Dear Allmighty Tech Readers,
I recently found out that you cannot dhclient a carp iface.
People jumped over that saying , blahblah must have ip .
Lies ! CARP require the two interface to have the same ip,
the mac will be the same so using dhcp to configure them is
working by design.
I have now a working solution , it s ugly, please consider
helping cleaning
this for future openbsd, it s really an improvement.
I will follow demands to clean it.
Problems :
1/ an invalid carp iface that is up, is considered down (not fixed),
also send_msg is not possible on up carp without ip. Tested with ugly
second chunk of dhclient.c patch
2/ dhclient is only accepting 'hardware' mac address
3/ when configuring interface , routehandler is having a similar problem
than 1. First chunk in the diff
CARP is obvisouly smart to cut communication of a backup interface, but i
think
invalid state is not backup state. So to fix 1 i would somehow consider
active an invalid and up carp interface: make sense to me. This would fix
1.
For now i just put a stupid ip with /32 subnet....
2/ Is solved with the part of diff i think should be already integrated,
see dispatch.c
I am not sure if getifaddrs is badly coded though, and the sdl_type is
somehow not set.
carp GOT a mac address .
3/ Well i just cheated for this one , i am not good enough to play fair.
Index: dhclient.c
===================================================================
RCS file: /cvs/src/sbin/dhclient/dhclient.c,v
retrieving revision 1.361
diff -u -p -r1.361 dhclient.c
--- dhclient.c 18 May 2015 14:59:42 -0000 1.361
+++ dhclient.c 5 Feb 2016 20:22:16 -0000
@@ -323,6 +323,10 @@ routehandler(void)
ifm = (struct if_msghdr *)rtm;
if (ifm->ifm_index != ifi->index)
break;
+ if (0 == strncmp("carp", ifi->name, 4)) {
+ note("rtm->rtm_flags(%08X) :%08X", rtm->rtm_flags,
RTF_UP);
+ rtm->rtm_flags = rtm->rtm_flags | RTF_UP; // Can i
be more ugly ? i wonder
+ }
if ((rtm->rtm_flags & RTF_UP) == 0) {
rslt = asprintf(&errmsg, "%s down", ifi->name);
goto die;
@@ -634,6 +638,11 @@ state_preboot(void)
ifi->linkstat = interface_status(ifi->name);
+ if (0 == strncmp("carp", ifi->name, 4)) {
+ note("carp is not down it is invalid :s");
+ ifi->linkstat = 1;
+ }
+
if (log_perror && interval > 3) {
if (!preamble && !ifi->linkstat) {
fprintf(stderr, "%s: no link ....", ifi->name);
@@ -858,6 +867,8 @@ dhcpack(struct in_addr client_addr, stru
/* Stop resending DHCPREQUEST. */
cancel_timeout();
+
+ note("Hello , we just get the data right");
bind_lease();
}
Index: dispatch.c
===================================================================
RCS file: /cvs/src/sbin/dhclient/dispatch.c,v
retrieving revision 1.102
diff -u -p -r1.102 dispatch.c
--- dispatch.c 18 May 2015 14:59:42 -0000 1.102
+++ dispatch.c 5 Feb 2016 20:22:16 -0000
@@ -78,7 +78,7 @@ get_hw_address(void)
continue;
sdl = (struct sockaddr_dl *)ifa->ifa_addr;
- if (sdl->sdl_type != IFT_ETHER ||
+ if ( !( sdl->sdl_type == IFT_ETHER || sdl->sdl_type ==
IFT_CARP ) ||
sdl->sdl_alen != ETHER_ADDR_LEN)
continue;
Test:
# ifconfig em5 down; ifconfig em5 down #was having a address here to cvs
# ifconfig carp1 vhid 55 carpdev em5 169.0.0.1 netmask 32
# CFLAGS=-g make && ./dhclient -d carp1
cc -g -Wall -Werror-implicit-function-declaration -c dhclient.c
cc -static -pie -o dhclient dhclient.o clparse.o dispatch.o bpf.o
options.o conflex.o errwarn.o packet.o tables.o parse.o privsep.o kroute.
o -lutil
DHCPDISCOVER on carp1 - interval 3
DHCPOFFER from 192.168.10.1 (fe:e1:ba:d0:1e:0d)
DHCPREQUEST on carp1 to 255.255.255.255
DHCPACK from 192.168.10.1 (fe:e1:ba:d0:1e:0d)
Hello , we just get the data right
rtm->rtm_flags(FFFF8802) :00000001
bound to 192.168.10.151 -- renewal in 60 seconds.
# # can now cvs diff like normal
Redundancy must be easy.
