[LT] Add vendor changes from bdk_freertos/v2.0.2 (ip4.c/ripple20)

src/core/ipv4/ip4.c

@@ -408,6 +408,51 @@ ip4_input_accept(struct netif *netif)
   return 0;
 }
 
+#if LWIP_RIPPLE20
+/**
+ * parse ipv4 IP options
+ * return: < 0 if IP options contain invalid option, = 0 Ok.
+ */
+int ip4_parse_opt(u8 *opt, int len)
+{
+	int ret = 0;
+	u8 type, item_len;
+
+	while (len > 1) {
+		type = *opt;
+		opt++;
+		item_len = *opt;
+		len -= item_len;
+		opt++;
+
+		/* avoid infinite recusive */
+		if (type != 0 && item_len == 0)
+			return -1;
+
+		switch (type) {
+		case 0:
+			/* End of Option List */
+			return ret;
+		case 7: {
+			/* RR Option */
+			u8 *pointer = opt;
+
+			if (*pointer < 4 || (*pointer % 4))
+				return -1;
+
+			break;
+		}
+
+		}
+
+		/* Forward to next option */
+		opt += item_len - 2;
+	}
+
+	return ret;
+}
+#endif /* LWIP_RIPPLE20 */
+
 /**
  * This function is called by the network interface device driver when
  * an IP packet is received. The function does the basic checks of the
@@ -470,6 +515,18 @@ ip4_input(struct pbuf *p, struct netif *inp)
     pbuf_realloc(p, iphdr_len);
   }
 
+#if LWIP_RIPPLE20
+  /* Parse IP options */
+  if (iphdr_hlen > 20) {
+  	u8 *opt = (u8*)p->payload;
+    if (ip4_parse_opt(opt + 20, iphdr_hlen - 20)) {
+      pbuf_free(p);
+      LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to invalid IP options\n"));
+      return ERR_OK;
+    }
+  }
+#endif
+
   /* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
   if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len) || (iphdr_hlen < IP_HLEN)) {
     if (iphdr_hlen < IP_HLEN) {