Index: sys/net/if_spppsubr.c
===================================================================
--- sys/net/if_spppsubr.c
+++ sys/net/if_spppsubr.c
@@ -131,6 +131,13 @@
 #define LCP_OPT_RESERVED	6	/* reserved */
 #define LCP_OPT_PROTO_COMP	7	/* protocol field compression */
 #define LCP_OPT_ADDR_COMP	8	/* address/control field compression */
+#define LCP_OPT_FCS_ALTS	9	/* FCS alternatives */
+#define LCP_OPT_SELF_DESC_PAD	10	/* self-describing padding */
+#define LCP_OPT_CALL_BACK	13	/* callback */
+#define LCP_OPT_COMPOUND_FRMS	15	/* compound frames */
+#define LCP_OPT_MP_MRRU		17	/* multilink MRRU */
+#define LCP_OPT_MP_SSNHF	18	/* multilink short seq. numbers */
+#define LCP_OPT_MP_EID		19	/* multilink endpoint discriminator */
 
 #define IPCP_OPT_ADDRESSES	1	/* both IP addresses; deprecated */
 #define IPCP_OPT_COMPRESSION	2	/* IP compression protocol (VJ) */
@@ -2319,6 +2326,36 @@
 			 */
 			sp->pp_flags |= PP_NEEDAUTH;
 			continue;
+		case LCP_OPT_MP_EID:
+			if (len >= p[1] && p[1] >= 3) {
+				if (debug)
+					log(-1, " [rej]");
+				break;
+			}
+			if (debug)
+				log(-1, " [invalid]");
+			break;
+		case LCP_OPT_MP_SSNHF:
+			if (len >= 2 && p[1] == 2) {
+				if (debug)
+					log(-1, " [rej]");
+				break;
+			}
+			if (debug)
+				log(-1, " [invalid]");
+			break;
+		case LCP_OPT_MP_MRRU:
+			/* Multilink maximum received reconstructed unit */
+			/* should be fall through, both are same length */
+			/* for now, check, then reject anyway */
+			if (len >= 4 && p[1] == 4) {
+				if (debug)
+					log(-1, " %d [rej]", (p[2] << 8) + p[3]);
+				break;
+			}
+			if (debug)
+				log(-1, " [invalid]");
+			break;
 		default:
 			/* Others not supported. */
 			if (debug)
@@ -5285,6 +5322,12 @@
 	case LCP_OPT_MAGIC:		return "magic";
 	case LCP_OPT_PROTO_COMP:	return "proto-comp";
 	case LCP_OPT_ADDR_COMP:		return "addr-comp";
+	case LCP_OPT_SELF_DESC_PAD:	return "sdpad";
+	case LCP_OPT_CALL_BACK:		return "callback";
+	case LCP_OPT_COMPOUND_FRMS:	return "cmpd-frms";
+	case LCP_OPT_MP_MRRU:		return "mrru";
+	case LCP_OPT_MP_SSNHF:		return "mp-ssnhf";
+	case LCP_OPT_MP_EID:		return "mp-eid";
 	}
 	snprintf (buf, sizeof(buf), "lcp/0x%x", opt);
 	return buf;