2 * Open connection for network block device
4 * Copyright 1997,1998 Pavel Machek, distribute under GPL
5 * <pavel@atrey.karlin.mff.cuni.cz>
7 * Version 1.0 - 64bit issues should be fixed, now
8 * Version 1.1 - added bs (blocksize) option (Alexey Guzeev, aga@permonline.ru)
9 * Version 1.2 - I added new option '-d' to send the disconnect request
10 * Version 2.0 - Version synchronised with server
11 * Version 2.1 - Check for disconnection before INIT_PASSWD is received
12 * to make errormsg a bit more helpful in case the server can't
13 * open the exported file.
14 * 16/03/2010 - Add IPv6 support.
15 * Kitt Tientanopajai <kitt@kitty.in.th>
16 * Neutron Soutmun <neo.neutron@gmail.com>
17 * Suriya Soutmun <darksolar@gmail.com>
23 #include <sys/ioctl.h>
24 #include <sys/socket.h>
25 #include <sys/types.h>
27 #include <netinet/tcp.h>
28 #include <netinet/in.h>
34 #include <sys/mount.h>
39 #error I need GCC to work
42 #include <linux/ioctl.h>
43 #define MY_NAME "nbd_client"
46 int check_conn(char* devname, int do_print) {
51 if(!strncmp(devname, "/dev/", 5)) {
54 if((p=strchr(devname, 'p'))) {
55 /* We can't do checks on partitions. */
58 snprintf(buf, 256, "/sys/block/%s/pid", devname);
59 if((fd=open(buf, O_RDONLY))<0) {
66 len=read(fd, buf, 256);
68 if(do_print) printf("%s\n", buf);
72 int opennet(char *name, int port, int sdp) {
75 struct addrinfo hints;
76 struct addrinfo *ai = NULL;
77 struct addrinfo *rp = NULL;
80 snprintf(portstr, sizeof(portstr), "%d", port);
82 memset(&hints,'\0',sizeof(hints));
83 hints.ai_family = AF_UNSPEC;
84 hints.ai_socktype = SOCK_STREAM;
85 hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
86 hints.ai_protocol = IPPROTO_TCP;
88 e = getaddrinfo(name, portstr, &hints, &ai);
91 fprintf(stderr, "getaddrinfo failed: %s\n", gai_strerror(e));
98 if (ai->ai_family == AF_INET)
99 ai->ai_family = AF_INET_SDP;
100 else (ai->ai_family == AF_INET6)
101 ai->ai_family = AF_INET6_SDP;
103 err("Can't do SDP: I was not compiled with SDP support!");
107 for(rp = ai; rp != NULL; rp = rp->ai_next) {
108 sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
111 continue; /* error */
113 if(connect(sock, rp->ai_addr, rp->ai_addrlen) != -1)
118 err("Socket failed: %m");
126 void negotiate(int sock, u64 *rsize64, u32 *flags) {
128 char buf[256] = "\0\0\0\0\0\0\0\0\0";
130 printf("Negotiation: ");
131 if (read(sock, buf, 8) < 0)
134 err("Server closed connection");
135 if (strcmp(buf, INIT_PASSWD))
136 err("INIT_PASSWD bad");
138 if (read(sock, &magic, sizeof(magic)) < 0)
140 magic = ntohll(magic);
141 if (magic != cliserv_magic)
142 err("Not enough cliserv_magic");
145 if (read(sock, &size64, sizeof(size64)) < 0)
146 err("Failed/3: %m\n");
147 size64 = ntohll(size64);
149 #ifdef NBD_SET_SIZE_BLOCKS
150 if ((size64>>10) > (~0UL >> 1)) {
151 printf("size = %luMB", (unsigned long)(size64>>20));
152 err("Exported device is too big for me. Get 64-bit machine :-(\n");
154 printf("size = %luKB", (unsigned long)(size64>>10));
156 if (size64 > (~0UL >> 1)) {
157 printf("size = %luKB", (unsigned long)(size64>>10));
158 err("Exported device is too big. Get 64-bit machine or newer kernel :-(\n");
160 printf("size = %lu", (unsigned long)(size64));
163 if (read(sock, flags, sizeof(*flags)) < 0)
164 err("Failed/4: %m\n");
165 *flags = ntohl(*flags);
167 if (read(sock, &buf, 124) < 0)
168 err("Failed/5: %m\n");
174 void setsizes(int nbd, u64 size64, int blocksize, u32 flags) {
176 int read_only = (flags & NBD_FLAG_READ_ONLY) ? 1 : 0;
178 #ifdef NBD_SET_SIZE_BLOCKS
179 if (size64/blocksize > (~0UL >> 1))
180 err("Device too large.\n");
183 if (ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long)blocksize) < 0)
184 err("Ioctl/1.1a failed: %m\n");
185 size = (unsigned long)(size64/blocksize);
186 if ((er = ioctl(nbd, NBD_SET_SIZE_BLOCKS, size)) < 0)
187 err("Ioctl/1.1b failed: %m\n");
188 fprintf(stderr, "bs=%d, sz=%lu\n", blocksize, size);
191 if (size64 > (~0UL >> 1)) {
192 err("Device too large.\n");
194 size = (unsigned long)size64;
195 if (ioctl(nbd, NBD_SET_SIZE, size) < 0)
196 err("Ioctl NBD_SET_SIZE failed: %m\n");
200 ioctl(nbd, NBD_CLEAR_SOCK);
202 if (ioctl(nbd, BLKROSET, (unsigned long) &read_only) < 0)
203 err("Unable to set read-only attribute for device");
206 void set_timeout(int nbd, int timeout) {
208 #ifdef NBD_SET_TIMEOUT
209 if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout) < 0)
210 err("Ioctl NBD_SET_TIMEOUT failed: %m\n");
211 fprintf(stderr, "timeout=%d\n", timeout);
213 err("Ioctl NBD_SET_TIMEOUT cannot be called when compiled on a system that does not support it\n");
218 void finish_sock(int sock, int nbd, int swap) {
219 if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
220 err("Ioctl NBD_SET_SOCK failed: %m\n");
223 mlockall(MCL_CURRENT | MCL_FUTURE);
226 int main(int argc, char *argv[]) {
229 char *hostname, *nbddev;
243 fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
244 fprintf(stderr, "Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-persist] [-nofork]\n");
245 fprintf(stderr, "Or : nbd-client -d nbd_device\n");
246 fprintf(stderr, "Or : nbd-client -c nbd_device\n");
247 fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
248 fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
249 fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
250 fprintf(stderr, "blocksizes other than 1024 without patches\n");
254 ++argv; --argc; /* skip programname */
256 if (strcmp(argv[0], "-d")==0) {
257 nbd = open(argv[1], O_RDWR);
259 err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
260 printf("Disconnecting: que, ");
261 if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
262 err("Ioctl failed: %m\n");
263 printf("disconnect, ");
264 #ifdef NBD_DISCONNECT
265 if (ioctl(nbd, NBD_DISCONNECT)<0)
266 err("Ioctl failed: %m\n");
269 fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
272 if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
273 err("Ioctl failed: %m\n");
277 if(strcmp(argv[0], "-c")==0) {
278 return check_conn(argv[1], 1);
281 if (strncmp(argv[0], "bs=", 3)==0) {
282 blocksize=atoi(argv[0]+3);
283 ++argv; --argc; /* skip blocksize */
286 if (strncmp(argv[0], "timeout=", 8)==0) {
287 timeout=atoi(argv[0]+8);
288 ++argv; --argc; /* skip timeout */
291 if (argc==0) goto errmsg;
293 ++argv; --argc; /* skip hostname */
295 if (argc==0) goto errmsg;
296 port = atoi(argv[0]);
297 ++argv; --argc; /* skip port */
299 if (argc==0) goto errmsg;
301 nbd = open(nbddev, O_RDWR);
303 err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
304 ++argv; --argc; /* skip device */
306 if (argc>4) goto errmsg;
309 if(strncmp(argv[0], "-swap", 5)==0) {
315 if(strncmp(argv[0], "-persist", 8)==0) {
321 if(strncmp(argv[0], "-sdp", 4)==0) {
327 if(strncmp(argv[0], "-nofork", 7)==0) {
333 if(argc) goto errmsg;
334 sock = opennet(hostname, port, sdp);
335 argv=NULL; argc=0; /* don't use it later suddenly */
337 negotiate(sock, &size64, &flags);
338 setsizes(nbd, size64, blocksize, flags);
339 set_timeout(nbd, timeout);
340 finish_sock(sock, nbd, swap);
345 if(!nofork) daemon(0,0);
348 /* Due to a race, the kernel NBD driver cannot
349 * call for a reread of the partition table
350 * in the handling of the NBD_DO_IT ioctl().
351 * Therefore, this is done in the first open()
352 * of the device. We therefore make sure that
353 * the device is opened at least once after the
354 * connection was made. This has to be done in a
355 * separate process, since the NBD_DO_IT ioctl()
356 * does not return until the NBD device has
359 while(check_conn(nbddev, 0)) {
362 open(nbddev, O_RDONLY);
367 if (ioctl(nbd, NBD_DO_IT) < 0) {
368 fprintf(stderr, "Kernel call returned: %m");
370 /* The user probably did 'nbd-client -d' on us.
378 fprintf(stderr, " Reconnecting\n");
379 close(sock); close(nbd);
380 sock = opennet(hostname, port, sdp);
381 nbd = open(nbddev, O_RDWR);
382 negotiate(sock, &new_size, &new_flags);
383 if (size64 != new_size) {
384 err("Size of the device changed. Bye");
386 setsizes(nbd, size64, blocksize,
389 set_timeout(nbd, timeout);
390 finish_sock(sock,nbd,swap);
394 /* We're on 2.4. It's not clearly defined what exactly
395 * happened at this point. Probably best to quit, now
397 fprintf(stderr, "Kernel call returned.");
401 printf("Closing: que, ");
402 ioctl(nbd, NBD_CLEAR_QUE);
404 ioctl(nbd, NBD_CLEAR_SOCK);