ISO(4) BSD Programmer's Manual ISO(4) NNAAMMEE iissoo - ISO protocol family SSYYNNOOPPSSIISS ##iinncclluuddee <<ssyyss//ttyyppeess..hh>> ##iinncclluuddee <<nneettiissoo//iissoo..hh>> DDEESSCCRRIIPPTTIIOONN The ISO protocol family is a collection of protocols that uses the ISO address format. The ISO family provides protocol support for the SOCK_SEQPACKET abstraction through the TP protocol (ISO 8073), for the SOCK_DGRAM abstraction through the connectionless transport protocol (ISO 8602), and for the SOCK_RAW abstraction by providing direct access (for debugging) to the CLNP (ISO 8473) network layer protocol. AADDDDRREESSSSIINNGG ISO addresses are based upon ISO 8348/AD2, _A_d_d_e_n_d_u_m _t_o _t_h_e _N_e_t_w_o_r_k _S_e_r_v_i_c_e _D_e_f_i_n_i_t_i_o_n _C_o_v_e_r_i_n_g _N_e_t_w_o_r_k _L_a_y_e_r _A_d_d_r_e_s_s_i_n_g_. Sockets bound to the OSI protocol family use the following address struc- ture: struct iso_addr { u_char isoa_len; /* length, not including this byte */ char isoa_genaddr[20]; /* general opaque address */ }; struct sockaddr_iso { u_char siso_len; /* size of this sockaddr */ u_char siso_family; /* addressing domain, AF_ISO */ u_char siso_plen; /* presentation selector length */ u_char siso_slen; /* session selector length */ u_char siso_tlen; /* transport selector length */ struct iso_addr siso_addr; /* network address */ u_char siso_pad[6]; /* space for gosip v2 SELs */ }; #define siso_nlen siso_addr.isoa_len #define siso_data siso_addr.isoa_genaddr The fields of this structure are: _s_i_s_o___l_e_n_: Length of the entire address structure, in bytes, which may grow to be longer than the 32 bytes show above. _s_i_s_o___f_a_m_i_l_y_: Identifies the domain: AF_ISO. _s_i_s_o___t_l_e_n_: Length of the transport selector. _s_i_s_o___s_l_e_n_: Length of the session selector. This is not currently supported by the kernel and is provided as a convenience for user level programs. _s_i_s_o___p_l_e_n_: Length of the presentation selector. This is not currently sup- ported by the kernel and is provided as a convenience for user level programs. _s_i_s_o___a_d_d_r_: The network part of the address, described below. TTRRAANNSSPPOORRTT AADDDDRREESSSSIINNGG An ISO transport address is similar to an Internet address in that it contains a network-address portion and a portion that the transport layer uses to multiplex its services among clients. In the Internet domain, this portion of the address is called a _p_o_r_t. In the ISO domain, this is called a _t_r_a_n_s_p_o_r_t _s_e_l_e_c_t_o_r (also known at one time as a _t_r_a_n_s_p_o_r_t _s_u_f_f_i_x). While ports are always 16 bits, transport selectors may be of (almost) arbitrary size. Since the C language does not provide conveninent variable length struc- tures, we have separated the selector lengths from the data themselves. The network address and various selectors are stored contiguously, with the network address first, then the transport selector, and so on. Thus, if you had a nework address of less then 20 bytes, the transport selector would encroach on space normally reserved for the network address. NNEETTWWOORRKK AADDDDRREESSSSIINNGG.. ISO network addresses are limited to 20 bytes in length. ISO network ad- dresses can take any format. PPRROOTTOOCCOOLLSS The ARGO 1.0 implementation of the ISO protocol family comprises the Con- nectionless-Mode Network Protocol (CLNP), and the Transport Protocol (TP), classes 4 and 0, and X.25. TP is used to support the SOCK_SEQPACKET abstraction. A raw interface to CLNP is available by creating an ISO socket of type SOCK_RAW. This is used for CLNP debugging only. SSEEEE AALLSSOO tp(4), clnp(4), cltp(4) 4.4BSD June 9, 1993 2