gistfile1.c

//
//  main.c
//  UVDickery
//
//  Created by Dylan Lukes on 3/21/12.
//  Copyright (c) 2012 Dylan Lukes. All rights reserved.
//

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#include "uv.h"

/* structs */

typedef struct {
    struct addrinfo *ai0;
    struct addrinfo *ai;
} connect_req_state_t;

/* prototypes */

void gai_cb(uv_getaddrinfo_t* handle, int status, struct addrinfo *res0);
void try_next_addrinfo(connect_req_state_t *req_state);
void connect_cb(uv_connect_t *req, int status);

/* statics */

static uv_loop_t *my_loop;

/* implementations */

void gai_cb(uv_getaddrinfo_t* handle, int status, struct addrinfo *ai0)
{
    if (status != 0) {
        fprintf(stderr, "uv_getaddrinfo: fatal: %s\n", gai_strerror(status));
        exit(EXIT_FAILURE);
    }
    
    connect_req_state_t *state = calloc(1, sizeof(connect_req_state_t));
    state->ai0 = ai0;
    state->ai = ai0;
    
    try_next_addrinfo(state);
    
    free(handle);
}

void try_next_addrinfo(connect_req_state_t *state)
{    
    uv_tcp_t *tcp_handle = calloc(1, sizeof(uv_tcp_t));
    
    uv_tcp_init(my_loop, tcp_handle);
    
    uv_connect_t *connect_req = calloc(1, sizeof(uv_connect_t));
    
    if (state->ai->ai_family == AF_INET) {
        uv_tcp_connect(connect_req, tcp_handle, *(struct sockaddr_in *)state->ai->ai_addr, connect_cb);
    } else if (state->ai->ai_family == AF_INET6) {
        uv_tcp_connect6(connect_req, tcp_handle, *(struct sockaddr_in6 *)state->ai->ai_addr, connect_cb);
    } else {
        fprintf(stderr, "try_next_ai: fatal: unexpected ai_family\n");
        exit(EXIT_FAILURE);
    }
    
    connect_req->data = state;
}

void connect_cb(uv_connect_t *req, int status)
{
    connect_req_state_t *state = (connect_req_state_t *)req->data;
    
    if (status != 0) {
        // Connection failed. Try the next addrinfo.
        
        if (state->ai->ai_next == NULL) {
            fprintf(stderr, "connect_cb: fatal: no remaining addrinfos\n");
            exit(EXIT_FAILURE);
        }
        
        state->ai = state->ai->ai_next;
        try_next_addrinfo(state);
    } else {
        // Connection succeeded. Release the addrinfo list.
        uv_freeaddrinfo(state->ai0);
        printf("Connection successful!\n");
    }
    
    free(req);
}

int main(int argc, const char *argv[])
{
    my_loop = uv_default_loop();
    
    struct addrinfo hints;
    
    memset(&hints, 0, sizeof(hints));
    hints.ai_family   = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    
    uv_getaddrinfo_t *gai_handle = calloc(1, sizeof(uv_getaddrinfo_t));
    
    uv_getaddrinfo(my_loop, gai_handle, gai_cb, "w f4f f f f3", "http", &hints);
    
    uv_run(my_loop);
}