udp服务端客户端

一个简单的udp客户端服务端代码：

公共文件部分：global.c

#include 
#include 
#include 
#include 
#include 
#include 
#include 

int
Socket(int family, int type, int protocol)
{
        int             n;

        if ( (n = socket(family, type, protocol)) < 0)
        {
                perror("socket error");
                exit(1);
        }
        return(n);
}

void
Bind(int fd, const struct sockaddr *sa, socklen_t salen)
{
        if (bind(fd, sa, salen) < 0)
        {
                perror("bind error");
                exit(1);
        }
}

void
Sendto(int fd, const void *ptr, size_t nbytes, int flags,
           const struct sockaddr *sa, socklen_t salen)
{
        if (sendto(fd, ptr, nbytes, flags, sa, salen) != (ssize_t)nbytes)
        {
                perror("sendto error");
                exit(1);
        }
}

ssize_t
Recvfrom(int fd, void *ptr, size_t nbytes, int flags,
                 struct sockaddr *sa, socklen_t *salenptr)
{
        ssize_t         n;

        if ( (n = recvfrom(fd, ptr, nbytes, flags, sa, salenptr)) < 0)
        {
                perror("recvfrom error");
                exit(1);
        }
        return(n);
}
                     

客户端：udpcli.c

#include "global.c"

int main(int argc, char* argv[])
{
        int sockfd;
        struct sockaddr_in conn_addr;
        struct sockaddr_in serv_addr;
        char buf[1024] = "hello,world";
        int n = 0;
        char serv_ip[INET_ADDRSTRLEN];
        socklen_t serv_addr_len;

        sockfd = Socket(AF_INET, SOCK_DGRAM, 0);

        conn_addr.sin_family = AF_INET;
        conn_addr.sin_port = htons(8345);
        if (inet_pton(AF_INET, "127.0.0.1", &conn_addr.sin_addr) == -1)
        {
                perror("inet_pton error\n");
                close(sockfd);
                exit(0);
        }
        serv_addr_len = sizeof(serv_addr);

        Sendto(sockfd, buf, sizeof(buf), 0, (struct sockaddr*)&conn_addr, sizeof(conn_addr));
        memset(buf, 0, sizeof(buf));
        n = recvfrom(sockfd, buf, sizeof(buf), 0, (struct sockaddr*)&serv_addr, &serv_addr_len);
        if (n > 0)
        {
                if (inet_ntop(AF_INET, &serv_addr.sin_addr, serv_ip, sizeof(serv_ip)) == NULL)
                {
                        perror("inet_ntop error\n");
                        close(sockfd);
                        exit(-1);
                }
                printf("recv data from %s : %d  %s\n", serv_ip, ntohs(serv_addr.sin_port), buf);
        }

        close(sockfd);
        exit(0);
}

udp服务端：udpserv.c

#include "global.c"

int main(int argc, char *argv[])
{
        int sockfd = 0;
        struct sockaddr_in serv_addr;
        struct sockaddr_in cli_addr;
        socklen_t cli_addr_len;
        char serv_ip[INET_ADDRSTRLEN];
        char buf[1024];

        sockfd = Socket(AF_INET, SOCK_DGRAM, 0);

        serv_addr.sin_family = AF_INET;
        serv_addr.sin_port = htons(8345);
        serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);

        if (inet_ntop(AF_INET, &serv_addr.sin_addr, serv_ip, sizeof(serv_ip)) == NULL) {
                printf("inet_ntop error\n");
                close(sockfd);
                exit(0);
        }
        printf("bind in %s : %d\n", serv_ip, ntohs(serv_addr.sin_port));

        Bind(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
        cli_addr_len = sizeof(cli_addr);

        Recvfrom(sockfd, buf, sizeof(buf), 0, (struct sockaddr*)&cli_addr, &cli_addr_len);
        printf("recv data from %s : %d  %s\n", inet_ntoa(cli_addr.sin_addr), ntohs(cli_addr.sin_port), buf);

        ssize_t nn = sendto(sockfd, buf, sizeof(buf), 0, (struct sockaddr*)&cli_addr, sizeof(cli_addr));
        if (nn == -1)
            printf("sendto error\n");
        printf("sendto %ld bytes\n", nn);

        close(sockfd);
        return 0;
}

makefile文件：Makefile

CC=gcc
CFLAGS=-Wall -std=c99 -pedantic
EXEC=server client

all: server client

client: udpcli.o
        $(CC) $(CFLAGS) udpcli.o -o client

udpcli.o: udpcli.c global.o
        $(CC) $(CFLAGS) -c udpcli.c -o udpcli.o

server: udpserv.o
        $(CC) $(CFLAGS) udpserv.o -o server

udpserv.o: udpserv.c global.o
        $(CC) $(CFLAGS) -c udpserv.c -o udpserv.o

global.o: global.c
        $(CC) $(CFLAGS) -c global.c -o global.o

clean:
        rm -f $(EXEC) *.o *~