CLNP(4) 1990 CLNP(4) NNAAMMEE clnp - Connectionless-Mode Network Protocol SSYYNNOOPPSSIISS ##iinncclluuddee <<ssyyss//ssoocckkeett..hh>> ##iinncclluuddee <<nneettaarrggoo//iissoo..hh>> ##iinncclluuddee <<nneettaarrggoo//ccllnnpp..hh>> ss == ssoocckkeett((AAFF__IISSOO,, SSOOCCKK__RRAAWW,, 00));; DDEESSCCRRIIPPTTIIOONN CLNP is the connectionless-mode network protocol used by the connectionless-mode network service. This protocol is speci- fied in ISO 8473. It may be accessed through a "raw socket" for debugging purposes only. CLNP sockets are connection- less, and are normally used with the _s_e_n_d_t_o and _r_e_c_v_f_r_o_m calls, though the _c_o_n_n_e_c_t(2) call may also be used to fix the destination for future packets (in which case the _r_e_a_d(2) or _r_e_c_v(2) and _w_r_i_t_e(2) or _s_e_n_d(2) system calls may be used). Outgoing packets automatically have a CLNP header prepended to them. Incoming packets received by the user contain the full CLNP header. The following _s_e_t_s_o_c_k_o_p_t options apply to CLNP: CLNPOPT_FLAGS Sets the flags which are passed to clnp when sending a datagram. Valid flags are: CLNP_NO_SEG-Do not allow segmentation CLNP_NO_ER-Suppress ER pdus CLNP_NO_CKSUM-Do not generate the CLNP checksum CLNPOPT_OPTS Sets CLNP options. The options must be formatted exactly as specified by ISO 8473, section 7.5 "Options Part." Once an option has been set, it will be sent on all packets until a different option is set. CCOONNGGEESSTTIIOONN EEXXPPEERRIIEENNCCEE BBIITT Whenever a packet is transmitted, the globally unique qual- ity of service option is added to the packet. The sequencing preferred bit and the low transit delay bit are set in this option. If a packet is forwarded containing the globally unique quality of service option, and the interface through which the packet will be transmitted has a queue length greater than _c_o_n_g_e_s_t__t_h_r_e_s_h_o_l_d, then the congestion experienced bit is set in the quality of service option. Printed 7/27/90 May 1 CLNP(4) 1990 CLNP(4) The threshold value stored in _c_o_n_g_e_s_t__t_h_r_e_s_h_o_l_d may be changed with the _c_l_n_l_u_t_i_l utility. When a packet is received with the globally unique quality of service option present, and the congestion experienced bit is set, then the transport congestion control function is called. DDIIAAGGNNOOSSTTIICCSS A socket operation may fail with one of the following errors returned: [EISCONN] when trying to establish a connection on a socket which already has one, or when trying to send a datagram with the destination address specified and the socket is already connected; [ENOTCONN] when trying to send a datagram, but no desti- nation address is specified, and the socket hasn't been connected; [ENOBUFS] when the system runs out of memory for an internal data structure; [EADDRNOTAVAIL] when an attempt is made to create a socket with a network address for which no network interface exists; [EHOSTUNREACH] when trying to send a datagram, but no route to the destination address exists. [EINVAL] when specifying unsupported options. SSEEEE AALLSSOO send(2), recv(2), intro(4), iso(4) BBUUGGSS Packets are sent with the type code of 0x1d (technically an invalid packet type) for lack of a better way to identify raw CLNP packets. No more than MLEN bytes of options can be specified. Printed 7/27/90 May 2