apr实现udp协议的一个问题
我修改这个服务端的范例代码想把tcp协议改成udp协议。我把里面的apr_socket_create这里用apr_socket_create(&s, sa->family, SOCK_DGRAM, APR_PROTO_UDP, mp);也就是用udp协议传输，结果rv = apr_socket_listen(s, DEF_SOCKET_BACKLOG);这里rv就不是success了。这是怎么回事呢，求助？
或者请给我一个用apr实现udp协议的范例让我看一下
/**
* apr tutorial sample code
* http://dev.ariel-networks.com/apr/
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <assert.h>
#include <apr_general.h>
#include <apr_file_io.h>
#include <apr_strings.h>
#include <apr_network_io.h>
/* default listen port number */
#define DEF_LISTEN_PORT8081
/* default socket backlog number. SOMAXCONN is a system default value */
#define DEF_SOCKET_BACKLOGSOMAXCONN
/* default buffer size */
#define BUFSIZE4096
/* useful macro */
#define CRLF_STR"\r\n"
static apr_status_t do_listen(apr_socket_t **sock, apr_pool_t *mp);
static int do_serv_task(apr_socket_t *serv_sock, apr_pool_t *mp);
/**
* Network server sample code
* Just response to an HTTP GET request, but this is not a true HTTP server.
* For example, you can test this program as follows,
* $ wget http://localhost:8081/etc/hosts
* @remark Error checks omitted
*/
int main(int argc, const char *argv[])
{
apr_status_t rv;
apr_pool_t *mp;
apr_socket_t *s;/* listening socket */
apr_initialize();
apr_pool_create(&mp, NULL);
rv = do_listen(&s, mp);
if (rv != APR_SUCCESS) {
goto error;
}
while (1) {
apr_socket_t *ns;/* accepted socket */
rv = apr_socket_accept(&ns, s, mp);
if (rv != APR_SUCCESS) {
goto error;
}
/* it is a good idea to specify socket options for the newly accepted socket explicitly */
apr_socket_opt_set(ns, APR_SO_NONBLOCK, 0);
apr_socket_timeout_set(ns, -1);
if (!do_serv_task(ns, mp)) {
goto error;
}
apr_socket_close(ns);
}
apr_pool_destroy(mp);
apr_terminate();
return 0;
error:
{
char errbuf[256];
apr_strerror(rv, errbuf, sizeof(errbuf));
printf("error: %d, %s\n", rv, errbuf);
}
apr_terminate();
return -1;
}
/**
* Create a listening socket, and listen it.
*/
static apr_status_t do_listen(apr_socket_t **sock, apr_pool_t *mp)
{
apr_status_t rv;
apr_socket_t *s;
apr_sockaddr_t *sa;
rv = apr_sockaddr_info_get(&sa, NULL, APR_INET, DEF_LISTEN_PORT, 0, mp);
if (rv != APR_SUCCESS) {
return rv;
}
rv = apr_socket_create(&s, sa->family, SOCK_STREAM, APR_PROTO_TCP, mp);
if (rv != APR_SUCCESS) {
return rv;
}
/* it is a good idea to specify socket options explicitly.
* in this case, we make a blocking socket as the listening socket */
apr_socket_opt_set(s, APR_SO_NONBLOCK, 0);
apr_socket_timeout_set(s, -1);
apr_socket_opt_set(s, APR_SO_REUSEADDR, 1);/* this is useful for a server(socket listening) process */
rv = apr_socket_bind(s, sa);
if (rv != APR_SUCCESS) {
return rv;
}
rv = apr_socket_listen(s, DEF_SOCKET_BACKLOG);
if (rv != APR_SUCCESS) {
return rv;
}
*sock = s;
return rv;
}
/**
* Response a file content as a simple HTTP response protocol.
* We assume that the request's first line is 'GET file-path HTTP/1.x'
*/
static int do_serv_task(apr_socket_t *sock, apr_pool_t *mp)
{
int is_firstline = TRUE;
const char *filepath = NULL;
/* read all inputs from the client */
/* XXX This is not a precise parser of HTTP requests.
* Don't misunderstand that apr_socket_recv() returns a line. It just returns a chunk of bytes */
while (1) {
char buf[BUFSIZE];
apr_size_t len = sizeof(buf) - 1;/* -1 for a null-terminated */
apr_status_t rv = apr_socket_recv(sock, buf, &len);
if (rv == APR_EOF || len == 0) {
break;
}
buf[len] = '\0';/* apr_socket_recv() doesn't return a null-terminated string */
if (is_firstline) {
char **tokens;
apr_tokenize_to_argv(buf, &tokens, mp);
if (tokens[0] && tokens[1] && strcmp(tokens[0], "GET") == 0) {
filepath = tokens[1];
}
is_firstline = FALSE;
}
if (strstr(buf, CRLF_STR CRLF_STR)) {/* expect the end of the request. no guarantee */
break;
}
}
if (filepath) {
apr_status_t rv;
apr_file_t *fp;
if ((rv = apr_file_open(&fp, filepath, APR_READ, APR_OS_DEFAULT, mp)) == APR_SUCCESS) {
const char *resp_hdr;
apr_size_t len;
const char *resp_body;
apr_finfo_t finfo;
apr_file_info_get(&finfo, APR_FINFO_SIZE, fp);
resp_hdr = apr_psprintf(mp, "HTTP/1.0 200 OK" CRLF_STR "Content-Length: %" APR_OFF_T_FMT CRLF_STR CRLF_STR, finfo.size);
len = strlen(resp_hdr);
apr_socket_send(sock, resp_hdr, &len);
resp_body = apr_palloc(mp, finfo.size);
len = finfo.size;
apr_file_read(fp, (void*)resp_body, &len);
apr_socket_send(sock, resp_body, &len);
return TRUE;
}
}
/* error case */
{
const char *resp_hdr = "HTTP/1.0 404 Not Found" CRLF_STR CRLF_STR;
apr_size_t len = strlen(resp_hdr);
apr_socket_send(sock, resp_hdr, &len);
return TRUE;
}
}
