hwtcp.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <stdlib.h>
#include <netinet/in.h>


#define STR "Hello tcp world\n"
#define pexit(x)                                \
        do {                                    \
                perror(x);                      \
                exit(EXIT_FAILURE);             \
        } while (0)


static struct sockaddr_in saddr;

int main(void)
{
        int sock, clisock;
        int len = strlen(STR);

        sock = socket(AF_INET, SOCK_STREAM, 0);

        saddr.sin_family = AF_INET;
        saddr.sin_addr.s_addr = htonl(INADDR_ANY);
        saddr.sin_port = htons(80);

        if (bind(sock, (struct sockaddr *)&saddr, sizeof(saddr)))
                pexit("bind");

        if (listen(sock, 10))
                pexit("listen");

        for (;;) {

                if ((clisock = accept(sock, NULL, NULL)) == -1) {
                        perror("accept");
                        continue;
                }

                if (send(clisock, STR, len, 0) != len)
                        perror("send");

                close(clisock);
        }

        return 0;
}