I believe that was a C-802 missile, but might not be manufactured in China, instead was build by Iran.
Iran also makes the C701, which has a heat seeking variant, whereas the C802 is radar only.
It has been suggested quite convincingly (cruse my failing memory, I cannot remember by who) that the attack on the INS Hanit was a well co-ordinated bait and switch which could have worked even if the Hanit had it's EW suit on at the time (there are also many credible questions about the official story that the Hanit had it's EW switch off but that's a different story).
The strategy was to launch a radar guided missile (C802) high and use that both to attract and focus the attention of the IDF as well as to use it's radar to get a location for the IDF ships, which would than be used to give an approximate heading to the low flying IR guided C701.
The idea is that since the C701 is IR homing it is passive and invisible to RWR based EW systems. The small size of the missile and low level flightpath would also help to minimize detection chances and detection range from the target's active radars. The C802 might also cause the target to train any IR detection gear they have at the C802, thus making it much more likely that the C701 would remain undetected.
The fact that the missile struck the helo idling on deck instead of the ship itself is a strong indication that the weapon as IR guided instead of radar guided as the ship would have had a bigger RCS than the helo, but might have had a small IR signature because of IR suppression measures.
The size of the detonation is also another indication that the weapon as a C701, as a C802's warhead would have obliterated the Hanit even with a close proximity detonation. Although there is a slight possibility that if it was a C802 that struck the helo, the armor-piercing warhead did not go off because of the low density of the helo compared to the ship hulls the missile was designed to penetrate, and it was only the helo's onboard fuel that cooked off which cause the explosive and fire damage to the ship.