Module 10 – Protocol Compiling & Lower-level RPC Programming

Module 10 – Protocol Compiling & Lower-level RPC Programming

Objectives • rpcgen에 대해 이해한다. • rpcgen을 이용하여 간단한 프로그램을 작성한다. • RPCL 언어에 대해 이해하고 사용 방법을 기술한다. • low-level RPC 인터페이스에 대해 이해한다. • 간단한 low-level 응용 프로그램을 작성한다. • RPC Library Interface 에 대해 이해 한다.

RPCGEN을이용한응용개발 user developed RPC Specification rpcgen shared filters & header file client stub server stub compile and link compile and link client functions server functions RPC and data representation libraries client executable server executable

Example - rpcgen • sqrt.x program SQRT_PROG { version SQRT_VERS { int getsqrt(int) = 1; } = 1; } = 0x20000088; • rpcgen에 의해 생성되는 파일 • sqrt.h • sqrt_clnt.c • sqrt_svc.c • sqrt_xdr.c

Protocol Definition Language (RPCL) • XDR definition language의 확장된 형태 • 프로토콜을 정의할 때 사용 • C syntax와 유사 • 확장자로 .x를 사용 • RPCGEN으로 컴파일(C source & header file) • RPCL의 구성 요소 • Definitions (6 types) • Declarations (4 types) • Special cases (4 types)

RPCL's definitions

RPCL's definitions(cont')

RPCL's declarations

Low-level RPC 응용 프로그램 • 프로토콜정의프로그램(application.x) • RPCGEN으로프로토콜정의프로그램compile • XDR routine 생성(application_xdr.c) • 프로토콜정의에대한include file 생성(application.h) • client stub 생성(application_clnt.c) • server stub 생성(application_svc.c) • 서버서비스프로그램(application_svc_proc.c) • server stub의dispatch 루틴에의해서호출될함수 • 클라이언트프로그램(application.c)

Client Side Function • clnt_create() #include <rpc/rpc.h> CLIENT clnt_create(host, prognum, versnum, protocol) • char *host; • u_long prognum, versnum; • char *protocol; • clnt_destroy() #include <rpc/rpc.h> void clnt_destroy(clnt) • CLIENT *clnt; • void svc_run() #include <rpc/rpc.h> bool_t clnt_control(clnt, request, info) • CLIENT *clnt; • int request; • char *info;

Client Side Function • clnt_call() enum clnt_stat clnt_call(clnt, procnum, inproc, in, outproc, out, time out) • CLIENT *clnt; • u_long prognum; • xdrproc_t inproc, outproc; • char *in, *out; • struct timeval timeout; struct timeval { • long tv_sec; /* seconds */ • long tv_usec; /* and microseconds */ • }

Server Side Function • svctcp_create() #include <rpc/rpc.h> SVCXPRT svctcp_create(sock, sendsz, recvsz) • int sock; • u_int sendz, recvsz; • svcudp_create() #include <rpc/rpc.h> SVCXPRT svcudp_create(sock) • int sock;

Example Program Client your code, includes main() rls.c readdir_1() client stub generated by compiler rls_clnt.c XDR Filters generated by compiler Network RPC protocol rls_xdr.c Server XDR Filters generated by compiler server stub generated by compiler rls_svc.c readdir_1() your code service procedures rls_svc_proc.c

rls.x • const MAXNAMELEN = 255; • typedef string nametype<MAXNAMELEN>; /* a directory entry */ • typedef struct namenode *namelist; /* a link in the listing */ • Struct namenode { • nametype name; /* name of directory entry */ • namelist pNext; /* next entry */ • }; • union readdir_res switch (int errno) { • case 0: • namelist list; /* no error: return directory listing */ • default: • void; /* error occurred: nothing else to return */ • }; • program DIRPROG { • version DIRVERS { • readdir_res READDIR(nametype) = 1; • } = 1; • } = 0x20000001;

Module 10 – Protocol Compiling & Lower-level RPC Programming