Multi-Process Network Service

1. High-performance Network Service Program

One of the advantages of Linux is that it can be used to design a variety of high performance network service programs, one of the characteristics of high performance is to achieve concurrent access processing, and simultaneously provide services to multiple online users, multi-process network services, multi-threaded network services, thread pool network services;

2. Multi-Process Network Service

: Using the parent-child process relationship in Linux system to provide concurrent services for multiple users is a popular concurrency service technology, the basic idea is: to a user, start a service process. If a new connection arrives, the child process starts interacting with it, and the child process exits automatically when the service finishes.

The model is as follows:

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3, the Code implementation:

A multi-process network service is simulated with an integer operation.

(1), utili.h

#include <unistd.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <sys /socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <pthread.h> #define Server_ PORT 9090#define server_ip "127.0.0.1" #define Listen_queue 5#define buffer_size 255typedef enum{add,sub,mul,div,mod    , quit}oper_type;typedef struct operstruct{int op1;    int OP2; Oper_type OPER;} Operstruct;

(2), ser.c

#include ". /utili.h "Void process_handler (Int sockconn); Void process_handler (Int sockConn) {     OperStruct op;     int result;     while (1) {        int res = recv (SockConn, &op,  sizeof (OP),  0);          if (res == -1) {             printf ("recv data fail.\n");             continue;         }           if (op.oper ==  ADD) {            result = op.op1 +  op.op2;        }else if (op.oper == sub)          {                result = op.op1 - op.op2;        }else  if (Op.oper == mul) {            result  = op.op1 * op.op2;        }else if (Op.oper  == DIV) {            result =  Op.op1 / op.op2;        }else if (op.oper ==  QUIT) {            break;         }           res =  Send (sockconn, &result, sizeof (result),  0);          if (RES ==&Nbsp;-1) {            printf ("send data  fail.\n ");            continue;         }    }    close (sockConn);} Int main (void) {    int sockser = socket (Af_inet, sock_stream,  0);     if (sockser == -1) {         Perror ("socket");         return -1;    }     struct sockaddr_in addrser, addrcli;    addrser.sin _family = af_inet;    addrser.sin_port = htons (SERVER_PORT);     ADDRSER.SIN_ADDR.S_ADDR = INET_ADDR (SERVER_IP);     socklen_t  len = sizeof (struct sOCKADDR);     int res = bind (sockser,  (struct sockaddr*) & Addrser, len);     if (res == -1) {         perror ("bind");         close (Sockser);         return -1;          }     listen (Sockser, listen_queue);    int sockconn;     while (1) {        printf ("server wait client  connect.......\n ");         sockconn = accept (SockSer,   (struct sockaddr*) &addrcli, &len);         if ( sockconn == -1) {            printf (" server accept client connect fail.\n ");            continue;         }else{             printf ("server accept client connect success.\n");             printf ("client ip:>%s\n",  inet_ntoa (AddrCli.sin_ addr));             printf ("Client Port:>%d \ n ", Ntohs (addrcli.sin_port));        }         pid_t pid;        pid = fork ();         if (pid == 0) {             close (Sockser);             process_handler(Sockconn);             exit (0);         }else if (pid > 0) {             close (Sockconn);             continue;            }else{             printf ("create process fail.\n");             continue;         }    }    close (SockSer);     return 0;}

(3), cli.c

#include "utili.h" Void inputdata (operstruct *pt); Void inputdata (OPERSTRUCT *PT) {     printf ("please input op1 and op2 : ");     scanf ("%d %d", & (PT->OP1), & (PT->OP2));} Cliint main (void) {    int sockcli = socket (AF_INET, SOCK_STREAM ,  0);      if (sockcli == -1) {         perror ("socket");        return -1;      }       struct sockaddr_in addrSer;     Addrser.sin_family = af_inet;    addrser.sin_port = htons (SERVER_PORT) ;     addrser.sin_addr.s_addr = inet_addr (SERVER_IP);     Socklen_t len = sizeof (STRUCT SOCKADDR);    int res = connect (sockcli,  (struct sockaddr*) &addrSer,  len);     if (res == -1) {         Perror ("Connect");         close (SOCKCLI);         return -1;     }else{         printf ("client connect server success.\n");    }     char cmd[2];    OperStruct  op;     Int result;    while (1) {        printf (" please input operator :  ");         SCANF ("%s ", cmd) ;         if (strcmp (cmd,  "+")  == 0) {             op.oper = add;             inputdata (&OP);         }else if (strcmp (cmd, "-")  ==  0) {            op.oper = sub;             inputdata (&OP);         }else if (strcmp (cmd, "*")  == 0) {             op.oper = MUL;             inputdata (&OP);         }else if (strcmp (cmd, "/")  == 0) {            op.oper = div;             inputdata (&OP);     &nBsp;   }else if (strcmp (cmd,  "quit")  == 0) {             op.oper = QUIT;         }else{                 printf ("cmd invalid.\n");        }         res = send (sockcli, &op, sizeof (OP),  0);         if (res == -1) {             printf ("send data fail.\n");             continue;        }         if (op.oper == quit)              break;        RES = RECV (sockcli, &result, sizeof (result),  0 );         if (res == -1) {             printf ("recv data fail.\n");             continue;        }         printf ("result = %d\n",  result);     }     close (SOCKCLI);     return 0;}

Operation Result:

Server-side

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Customer 1

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Customer 2

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4. Analysis of results

(1), utili.h in Ser.c, utili.h and CLI.C are in the same level directory;

(2), Process server: Socker is a reference counter model, close () is reduced by one, and does not really close, each time a process is created will give Socker reference counter plus 1;

(3), disadvantages: A, start and close the sub-process brings a lot of overhead; B, the system can only produce up to 512 processes, that is, up to only 512 customers, can not handle the situation of large-scale access;

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Multi-Process Network Service