Assuming that the pledge bits are in, the diff below enables setting of
MTU on the interface by slaacd.
If a MTU is advertised it is checked that it is at least 1280 bytes. If
not MTU is set to 1280. If no MTU is advertised nothing is done.
diff --git sbin/slaacd/engine.c sbin/slaacd/engine.c
index 58c39fb5c4a..762fb3af7a3 100644
--- sbin/slaacd/engine.c
+++ sbin/slaacd/engine.c
@@ -164,6 +164,7 @@ struct radv {
LIST_HEAD(, radv_rdns) rdns_servers;
uint32_t dnssl_lifetime;
LIST_HEAD(, radv_dnssl) dnssls;
+ uint32_t mtu;
};
struct address_proposal {
@@ -185,6 +186,7 @@ struct address_proposal {
uint32_t vltime;
uint32_t pltime;
uint8_t soiikey[SLAACD_SOIIKEY_LEN];
+ uint32_t mtu;
};
struct dfr_proposal {
@@ -1193,6 +1195,7 @@ parse_ra(struct slaacd_iface *iface, struct imsg_ra *ra)
struct nd_opt_prefix_info *prf;
struct nd_opt_rdnss *rdnss;
struct nd_opt_dnssl *dnssl;
+ struct nd_opt_mtu *mtu;
struct in6_addr *in6;
int i;
char *nssl;
@@ -1293,11 +1296,23 @@ parse_ra(struct slaacd_iface *iface, struct imsg_ra *ra)
LIST_INSERT_HEAD(&radv->dnssls, ra_dnssl, entries);
+ break;
+ case ND_OPT_MTU:
+ if (nd_opt_hdr->nd_opt_len != 1) {
+ log_warnx("invalid ND_OPT_MTU: len != 1");
+ goto err;
+ }
+ mtu = (struct nd_opt_mtu*) nd_opt_hdr;
+ radv->mtu = ntohl(mtu->nd_opt_mtu_mtu);
+
+ /* path MTU cannot be less than IPV6_MMTU */
+ if (radv->mtu < IPV6_MMTU)
+ radv->mtu = IPV6_MMTU;
+
break;
case ND_OPT_REDIRECTED_HEADER:
case ND_OPT_SOURCE_LINKADDR:
case ND_OPT_TARGET_LINKADDR:
- case ND_OPT_MTU:
case ND_OPT_ROUTE_INFO:
#if 0
log_debug("\tOption: %u (len: %u) not implemented",
@@ -1902,6 +1917,7 @@ configure_address(struct address_proposal *addr_proposal)
address.vltime = addr_proposal->vltime;
address.pltime = addr_proposal->pltime;
address.privacy = addr_proposal->privacy;
+ address.mtu = addr_proposal->mtu;
engine_imsg_compose_main(IMSG_CONFIGURE_ADDRESS, 0, &address,
sizeof(address));
@@ -1950,6 +1966,8 @@ gen_address_proposal(struct slaacd_iface *iface, struct
radv *ra, struct
addr_proposal->pltime = prefix->pltime;
}
+ addr_proposal->mtu = ra->mtu;
+
gen_addr(iface, prefix, addr_proposal, privacy);
tv.tv_sec = 0;
diff --git sbin/slaacd/engine.h sbin/slaacd/engine.h
index e7f520f1fba..4493b621b13 100644
--- sbin/slaacd/engine.h
+++ sbin/slaacd/engine.h
@@ -34,6 +34,7 @@ struct imsg_configure_address {
struct in6_addr mask;
uint32_t vltime;
uint32_t pltime;
+ uint32_t mtu;
int privacy;
};
diff --git sbin/slaacd/slaacd.c sbin/slaacd/slaacd.c
index 7afd9dc3ec7..617c6620e20 100644
--- sbin/slaacd/slaacd.c
+++ sbin/slaacd/slaacd.c
@@ -761,6 +761,18 @@ configure_interface(struct imsg_configure_address *address)
if (ioctl(ioctl_sock, SIOCAIFADDR_IN6, &in6_addreq) < 0)
fatal("SIOCAIFADDR_IN6");
+
+ if (address->mtu) {
+ struct ifreq ifr;
+
+ (void) strlcpy(ifr.ifr_name, in6_addreq.ifra_name,
+ sizeof(ifr.ifr_name));
+ ifr.ifr_mtu = address->mtu;
+ log_debug("Setting MTU to %d", ifr.ifr_mtu);
+
+ if (ioctl(ioctl_sock, SIOCSIFMTU, &ifr) < 0)
+ fatal("SIOCSIFMTU");
+ }
}
void
