socketserverudp.c

基于嵌入式linux下

#include <stdio.h>      /* for printf() and fprintf() */
#include <sys/socket.h> /* for socket() and bind() */
#include <arpa/inet.h>  /* for sockaddr_in and inet_ntoa() */
#include <stdlib.h>     /* for atoi() and exit() */
#include <string.h>     /* for memset() */
#include <unistd.h>     /* for close() */

#define ECHOMAX 255     /* Longest string to echo */

//void DieWithError(char *errorMessage);  /* External error handling function */

int main(int argc, char *argv[])
{
    int sock;                        /* Socket */
    struct sockaddr_in echoServAddr; /* Local address */
    struct sockaddr_in echoClntAddr; /* Client address */
    unsigned int cliAddrLen;         /* Length of incoming message */
    char echoBuffer[ECHOMAX];        /* Buffer for echo string */
    unsigned short echoServPort;     /* Server port */
    int recvMsgSize;                 /* Size of received message */

    if (argc != 2)         /* Test for correct number of parameters */
    {
        fprintf(stderr,"Usage:  %s <UDP SERVER PORT>\n", argv[0]);
        //exit(1);
    }

	echoServPort=5000;
	
    //echoServPort = atoi(argv[1]);  /* First arg:  local port */
    
    printf("echoServPort:%d\r\n",echoServPort);

    /* Create socket for sending/receiving datagrams */
    if ((sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
        printf("socket fail!\r\n");

    /* Construct local address structure */
    memset(&echoServAddr, 0, sizeof(echoServAddr));   /* Zero out structure */
    echoServAddr.sin_family = AF_INET;                /* Internet address family */
    echoServAddr.sin_addr.s_addr =INADDR_ANY;//inet_addr("192.168.0.138"); //htonl(INADDR_ANY); /* Any incoming interface */
    echoServAddr.sin_port = htons(echoServPort);      /* Local port */

    /* Bind to the local address */
    if (bind(sock, (struct sockaddr *) &echoServAddr, sizeof(echoServAddr)) < 0)
    {
        //printf("address:%s!\r\n",inet_ntoa(echoServAddr.sin_addr.s_addr));//inet_neta
        printf("bind fail!\r\n");
        exit(1);
    }
  
    for (;;) /* Run forever */
    {
        /* Set the size of the in-out parameter */
        cliAddrLen = sizeof(echoClntAddr);

        /* Block until receive message from a client */
        if ((recvMsgSize = recvfrom(sock, echoBuffer, ECHOMAX, 0,
            (struct sockaddr *) &echoClntAddr, &cliAddrLen)) < 0)
            printf("recv fail!\r\n");

	

	echoBuffer[recvMsgSize] = '\0';

        printf("Handling client %s: %s\n", inet_ntoa(echoClntAddr.sin_addr),echoBuffer );
        
        int i;
    	for (i=0;i<recvMsgSize;i++)
    	{
    		printf("1:%d",i);
    		printf("echoBuffer:%02x\r\n",echoBuffer[i] & 0xFF);
    	}

        /* Send received datagram back to the client */
        if (sendto(sock, echoBuffer, recvMsgSize, 0, 
             (struct sockaddr *) &echoClntAddr, sizeof(echoClntAddr)) != recvMsgSize)
            printf("sendto fail!\r\n");
    }
    /* NOT REACHED */
}