1 files changed, 147 insertions, 0 deletions
diff --git a/server/net.c b/server/net.c
new file mode 100644
index 0000000..02db9aa
--- /dev/null
+++ b/server/net.c
@@ -0,0 +1,147 @@
+/*
+ * 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;
+}