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/*
* net.c - network stuff for the server
* Copyright (C) 2006 Thorsten Zitterell <thorsten@zitterell.de>
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#define DNBD_USERSPACE 1
#include "../common/dnbd-cliserv.h"
#include "net.h"
struct listener_s {
pthread_t tid;
net_request_t *request;
};
typedef struct listener_s listener_t;
listener_t listener;
/*
* function net_tx(): send a server reply
*/
void net_tx(net_info_t * net_info, net_reply_t * reply)
{
if (sendto
(net_info->sock, reply->data, reply->len, 0,
(struct sockaddr *) &net_info->groupnet,
sizeof(net_info->groupnet)) < 0)
fprintf(stderr, "net_tx: mcast sendproblem\n");
}
/*
* function net_rx(): receive a client request
* returns: 1 on correct size of reply, otherwise 0
*/
int net_rx(net_info_t * net_info, net_request_t * request)
{
ssize_t n;
request->clientlen = sizeof(request->client);
n = recvfrom(net_info->sock, &request->data,
sizeof(request->data), 0,
&request->client, &request->clientlen);
/* sizeof of request must be size of a DNBD request */
return (n == sizeof(request->data) ? 1 : 0);
}
/*
* function net_init(): initialize network for multicast
* returns: structure with network related information
*/
net_info_t *net_init(const char *mnet)
{
struct ip_mreq mreq;
const int ttl = 64; /* TTL of 64 should be enough */
u_char loop = 0;
net_info_t *net_info = NULL;
net_info = (net_info_t *) malloc(sizeof(net_info_t));
if (!net_info)
return NULL;
memset(net_info, 0, sizeof(net_info_t));
/* network setup */
net_info->server.sin_family = AF_INET;
net_info->server.sin_port = htons(DNBD_PORT);
net_info->sock = socket(PF_INET, SOCK_DGRAM, 0);
if (!inet_aton(mnet, &net_info->server.sin_addr)) {
fprintf(stderr,
"ERROR: multicast group %s is not a valid address!\n",
mnet);
goto out_free;
}
if (bind
(net_info->sock, (struct sockaddr *) &net_info->server,
sizeof(net_info->server)) < 0) {
fprintf(stderr, "ERROR: binding socket!\n");
goto out_free;
}
if (!inet_aton(mnet, &net_info->groupnet.sin_addr)) {
fprintf(stderr,
"ERROR: multicast group %s is not a valid address!\n",
mnet);
goto out_free;
}
/* multicast setup */
net_info->groupnet.sin_family = AF_INET;
net_info->groupnet.sin_port = htons(DNBD_PORT);
mreq.imr_interface.s_addr = htonl(INADDR_ANY);
memcpy(&mreq.imr_multiaddr, &net_info->groupnet.sin_addr,
sizeof(struct in_addr));
if (setsockopt
(net_info->sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq,
sizeof(mreq)) < 0) {
fprintf(stderr,
"ERROR: cannot add multicast membership!\n");
goto out_free;
}
if (setsockopt(net_info->sock, IPPROTO_IP, IP_MULTICAST_TTL,
&ttl, sizeof(ttl)) < 0) {
fprintf(stderr, "ERROR: Setting TTL to 2\n");
goto out_free;
}
/* no looping, please */
if (setsockopt
(net_info->sock, IPPROTO_IP, IP_MULTICAST_LOOP, &loop,
sizeof(loop)) < 0) {
fprintf(stderr,
"ERROR: cannot disable multicast looping!\n");
goto out_free;
}
goto out;
out_free:
fprintf(stderr,
"hint: check kernel multicast support, multicast routing\n");
if (net_info)
free(net_info);
net_info = NULL;
out:
return net_info;
}
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