On Fri, Sep 06, 2019 at 09:15:16PM +0200, Sebastian Benoit wrote:
> Florian Obser(flor...@openbsd.org) on 2019.09.06 16:51:35 +0200:
> > On Wed, Sep 04, 2019 at 06:07:35PM +0200, Matthieu Herrb wrote:
> > > Hi,
> > >
> > > I've a pair of redundant routers, which need to run rad(8) on the
> > > internal interfaces.
> > >
> > > But using carp, on the inactive router, rad complains every
> > > time it tries to send a RA:
> > >
> > > rad[65590]: sendmsg on carp2: Can't assign requested address
> > >
> > > Which I can understand since it currently doesnt "own" the shared IPv6
> > > address of the carp interface.
> > >
> > > Is there a way to configure rad to avoid these errors?
> > > How do other people handle the situation?
> > >
> > > Thanks in advance,
> > > --
> > > Matthieu Herrb
> > >
> >
> > This should keep the noise down.
> >
> > OK?
>
> comment inline
>
> > if ((ra_iface = find_ra_iface_by_name(name)) != NULL) {
> > - log_debug("keeping interface %s", name);
> > - ra_iface->removed = 0;
> > + ra_iface->link_state = link_state;
> > + if (link_state == LINK_STATE_DOWN) {
>
> note that there are some (physical) interfaces that do not report a link
> state and thus are unknown even when they can send packets.
I know, observe how I don't care about UP but rather DOWN.
> Use the LINK_STATE_IS_UP() macro here.
Probably best to use !LINK_STATE_IS_UP() :P
>
> Do we need to consider the case of an interface being administratively down
> here (!(ifap->flags & IFF_UP))?.
I checked, no. sendmsg doesn't error out, the packet is just not going
out. I would leave it at that.
diff --git frontend.c frontend.c
index 8178b058629..3cf52fb4127 100644
--- frontend.c
+++ frontend.c
@@ -104,6 +104,7 @@ struct ra_iface {
char conf_name[IF_NAMESIZE];
uint32_t if_index;
int removed;
+ int link_state;
int prefix_count;
size_t datalen;
uint8_t data[RA_MAX_SIZE];
@@ -117,6 +118,7 @@ void frontend_startup(void);
void icmp6_receive(int, short, void *);
void join_all_routers_mcast_group(struct ra_iface *);
void leave_all_routers_mcast_group(struct ra_iface *);
+int get_link_state(char *);
void merge_ra_interface(char *, char *);
void merge_ra_interfaces(void);
struct ra_iface *find_ra_iface_by_id(uint32_t);
@@ -720,21 +722,59 @@ find_ra_iface_conf(struct ra_iface_conf_head *head, char
*if_name)
return (NULL);
}
+int
+get_link_state(char *if_name)
+{
+ struct ifaddrs *ifap, *ifa;
+ int ls = LINK_STATE_UNKNOWN;
+
+ if (getifaddrs(&ifap) != 0) {
+ log_warn("getifaddrs");
+ return LINK_STATE_UNKNOWN;
+ }
+ for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
+ if (ifa->ifa_addr->sa_family != AF_LINK)
+ continue;
+ if (strcmp(if_name, ifa->ifa_name) != 0)
+ continue;
+
+ ls = ((struct if_data*)ifa->ifa_data)->ifi_link_state;
+ break;
+ }
+ freeifaddrs(ifap);
+ return ls;
+}
+
void
merge_ra_interface(char *name, char *conf_name)
{
struct ra_iface *ra_iface;
uint32_t if_index;
+ int link_state;
+
+ link_state = get_link_state(name);
if ((ra_iface = find_ra_iface_by_name(name)) != NULL) {
- log_debug("keeping interface %s", name);
- ra_iface->removed = 0;
+ ra_iface->link_state = link_state;
+ if (!LINK_STATE_IS_UP(link_state)) {
+ log_debug("%s down, ignoring", name);
+ ra_iface->removed = 1;
+ } else {
+ log_debug("keeping interface %s", name);
+ ra_iface->removed = 0;
+ }
+ return;
+ }
+
+ if (!LINK_STATE_IS_UP(link_state)) {
+ log_debug("%s down, ignoring", name);
return;
}
log_debug("new interface %s", name);
if ((if_index = if_nametoindex(name)) == 0)
return;
+
log_debug("adding interface %s", name);
if ((ra_iface = calloc(1, sizeof(*ra_iface))) == NULL)
fatal("%s", __func__);
@@ -1135,6 +1175,9 @@ ra_output(struct ra_iface *ra_iface, struct sockaddr_in6
*to)
ssize_t len;
int hoplimit = 255;
+ if (!LINK_STATE_IS_UP(ra_iface->link_state))
+ return;
+
sndmhdr.msg_name = to;
sndmhdr.msg_iov[0].iov_base = ra_iface->data;
sndmhdr.msg_iov[0].iov_len = ra_iface->datalen;
--
I'm not entirely sure you are real.
