tcp.c

#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>

#include "tcp.h"

int lookup(char *host, char *portnr, struct addrinfo **res)
{
    struct addrinfo hints;
    memset(&hints, 0, sizeof(struct addrinfo));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_NUMERICSERV;
    hints.ai_protocol = 0;

    return getaddrinfo(host, portnr, &hints, res);
}

int connect_to(struct addrinfo *addr, struct timeval *rtt)
{
    int fd;
    struct timeval start;
    int connect_result;
    const int on = 1;
    /* int flags; */
    int rv = 0;

    /* try to connect for each of the entries: */
    while (addr != NULL)
    {
        /* create socket */
        if ((fd = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol)) == -1)
            goto next_addr0;
        if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0)
            goto next_addr1;
#if 0
        if ((flags = fcntl(fd, F_GETFL, 0)) == -1)
            goto next_addr1;
        if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
            goto next_addr1;
#endif
        if (gettimeofday(&start, NULL) == -1)
            goto next_addr1;

        /* connect to peer */
        if ((connect_result = connect(fd, addr->ai_addr, addr->ai_addrlen)) == 0)
        {
            if (gettimeofday(rtt, NULL) == -1)
                goto next_addr1;
            rtt->tv_sec = rtt->tv_sec - start.tv_sec;
            rtt->tv_usec = rtt->tv_usec - start.tv_usec;
            close(fd);
            return 0;
        }

next_addr1:
        close(fd);
next_addr0:
        addr = addr->ai_next;
    }

    rv = rv ? rv : -errno;
    return rv;
}