BSD: Try and set linkmtu for the interface just to be nice.

If it fails, zero it out and try again - only the linkmtu should
fail really. This is fine as we fix it against the route itself.

diff --git a/src/if-bsd.c b/src/if-bsd.c
index c629a7ddd6db17b5d376b6774a6e99e5372f893f..a0870b923494ef7a4a61d43d171c52bfdd129b17 100644 (file)
--- a/src/if-bsd.c
+++ b/src/if-bsd.c
@@ -1490,15 +1490,29 @@ if_applyra(const struct ra *rap)
 #ifdef SIOCSIFINFO_IN6
        struct in6_ndireq ndi = { .ndi.chlim = 0 };
        struct priv *priv = rap->iface->ctx->priv;
+       int error;
 
        strlcpy(ndi.ifname, rap->iface->name, sizeof(ndi.ifname));
        if (ioctl(priv->pf_inet6_fd, SIOCGIFINFO_IN6, &ndi) == -1)
                return -1;
 
+       ndi.ndi.linkmtu = rap->mtu;
        ndi.ndi.chlim = rap->hoplimit;
        ndi.ndi.retrans = rap->retrans;
        ndi.ndi.basereachable = rap->reachable;
-       return ioctl(priv->pf_inet6_fd, SIOCSIFINFO_IN6, &ndi);
+       error = ioctl(priv->pf_inet6_fd, SIOCSIFINFO_IN6, &ndi);
+       if (error == -1 && errno == EINVAL) {
+               /*
+                * Very likely that this is caused by a dodgy MTU
+                * setting specific to the interface.
+                * Let's set it to "unspecified" and try again.
+                * Doesn't really matter as we fix the MTU against the
+                * routes we add as not all OS support SIOCSIFINFO_IN6.
+                */
+               ndi.ndi.linkmtu = 0;
+               error = ioctl(priv->pf_inet6_fd, SIOCSIFINFO_IN6, &ndi);
+       }
+       return error;
 #else
 #warning OS does not allow setting of RA bits hoplimit, retrans or reachable
        UNUSED(rap);