+ /*
+ * Step 3: Process LISTEN state
+ * If S.state == LISTEN,
+ * If P.type == Request or P contains a valid Init Cookie option,
+ * (* Must scan the packet's options to check for Init
+ * Cookies. Only Init Cookies are processed here,
+ * however; other options are processed in Step 8. This
+ * scan need only be performed if the endpoint uses Init
+ * Cookies *)
+ * (* Generate a new socket and switch to that socket *)
+ * Set S := new socket for this port pair
+ * S.state = RESPOND
+ * Choose S.ISS (initial seqno) or set from Init Cookies
+ * Initialize S.GAR := S.ISS
+ * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
+ * Continue with S.state == RESPOND
+ * (* A Response packet will be generated in Step 11 *)
+ * Otherwise,
+ * Generate Reset(No Connection) unless P.type == Reset
+ * Drop packet and return
+ *
+ * NOTE: the check for the packet types is done in
+ * dccp_rcv_state_process
+ */