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