qemu-nbd tool (Anthony Liguori)

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4596 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 500 insertions, 0 deletions

diff --git a/nbd.c b/nbd.c
new file mode 100644
index 0000000000..fcf0339292
--- /dev/null
+++ b/nbd.c
@@ -0,0 +1,500 @@
+/*\
+ *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
+ *
+ *  Network Block Device
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+\*/
+
+#include "nbd.h"
+
+#include <errno.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <ctype.h>
+#include <inttypes.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+extern int verbose;
+
+#define LOG(msg, ...) do { \
+    fprintf(stderr, "%s:%s():L%d: " msg "\n", \
+            __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
+} while(0)
+
+#define TRACE(msg, ...) do { \
+    if (verbose) LOG(msg, ## __VA_ARGS__); \
+} while(0)
+
+/* This is all part of the "official" NBD API */
+
+#define NBD_REQUEST_MAGIC       0x25609513
+#define NBD_REPLY_MAGIC         0x67446698
+
+#define NBD_SET_SOCK            _IO(0xab, 0)
+#define NBD_SET_BLKSIZE         _IO(0xab, 1)
+#define NBD_SET_SIZE            _IO(0xab, 2)
+#define NBD_DO_IT               _IO(0xab, 3)
+#define NBD_CLEAR_SOCK          _IO(0xab, 4)
+#define NBD_CLEAR_QUE           _IO(0xab, 5)
+#define NBD_PRINT_DEBUG	        _IO(0xab, 6)
+#define NBD_SET_SIZE_BLOCKS	_IO(0xab, 7)
+#define NBD_DISCONNECT          _IO(0xab, 8)
+
+/* That's all folks */
+
+#define read_sync(fd, buffer, size) wr_sync(fd, buffer, size, true)
+#define write_sync(fd, buffer, size) wr_sync(fd, buffer, size, false)
+
+static size_t wr_sync(int fd, void *buffer, size_t size, bool do_read)
+{
+    size_t offset = 0;
+
+    while (offset < size) {
+        ssize_t len;
+
+        if (do_read) {
+            len = read(fd, buffer + offset, size - offset);
+        } else {
+            len = write(fd, buffer + offset, size - offset);
+        }
+
+        /* recoverable error */
+        if (len == -1 && errno == EAGAIN) {
+            continue;
+        }
+
+        /* eof */
+        if (len == 0) {
+            break;
+        }
+
+        /* unrecoverable error */
+        if (len == -1) {
+            return 0;
+        }
+
+        offset += len;
+    }
+
+    return offset;
+}
+
+static int tcp_socket_outgoing(const char *address, uint16_t port)
+{
+    int s;
+    struct in_addr in;
+    struct sockaddr_in addr;
+    int serrno;
+
+    s = socket(PF_INET, SOCK_STREAM, 0);
+    if (s == -1) {
+        return -1;
+    }
+
+    if (inet_aton(address, &in) == 0) {
+        struct hostent *ent;
+
+        ent = gethostbyname(address);
+        if (ent == NULL) {
+            goto error;
+        }
+
+        memcpy(&in, ent->h_addr, sizeof(in));
+    }
+
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(port);
+    memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
+
+    if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+        goto error;
+    }
+
+    return s;
+error:
+    serrno = errno;
+    close(s);
+    errno = serrno;
+    return -1;
+}
+
+int tcp_socket_incoming(const char *address, uint16_t port)
+{
+    int s;
+    struct in_addr in;
+    struct sockaddr_in addr;
+    int serrno;
+    int opt;
+
+    s = socket(PF_INET, SOCK_STREAM, 0);
+    if (s == -1) {
+        return -1;
+    }
+
+    if (inet_aton(address, &in) == 0) {
+        struct hostent *ent;
+
+        ent = gethostbyname(address);
+        if (ent == NULL) {
+            goto error;
+        }
+
+        memcpy(&in, ent->h_addr, sizeof(in));
+    }
+
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(port);
+    memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
+
+    opt = 1;
+    if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) == -1) {
+        goto error;
+    }
+
+    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+        goto error;
+    }
+
+    if (listen(s, 128) == -1) {
+        goto error;
+    }
+
+    return s;
+error:
+    serrno = errno;
+    close(s);
+    errno = serrno;
+    return -1;
+}
+
+/* Basic flow
+
+   Server         Client
+
+   Negotiate
+                  Request
+   Response
+                  Request
+   Response
+                  ...
+   ...
+                  Request (type == 2)
+*/
+
+int nbd_negotiate(BlockDriverState *bs, int csock, off_t size)
+{
+	char buf[8 + 8 + 8 + 128];
+
+	/* Negotiate
+	   [ 0 ..   7]   passwd   ("NBDMAGIC")
+	   [ 8 ..  15]   magic    (0x00420281861253)
+	   [16 ..  23]   size
+	   [24 .. 151]   reserved (0)
+	 */
+
+	TRACE("Beginning negotiation.");
+	memcpy(buf, "NBDMAGIC", 8);
+	cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
+	cpu_to_be64w((uint64_t*)(buf + 16), size);
+	memset(buf + 24, 0, 128);
+
+	if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+		LOG("write failed");
+		errno = EINVAL;
+		return -1;
+	}
+
+	TRACE("Negotation succeeded.");
+
+	return 0;
+}
+
+int nbd_receive_negotiate(int fd, int csock)
+{
+	char buf[8 + 8 + 8 + 128];
+	uint64_t magic;
+	off_t size;
+	size_t blocksize;
+
+	TRACE("Receiving negotation.");
+
+	if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+		LOG("read failed");
+		errno = EINVAL;
+		return -1;
+	}
+
+	magic = be64_to_cpup((uint64_t*)(buf + 8));
+	size = be64_to_cpup((uint64_t*)(buf + 16));
+	blocksize = 1024;
+
+	TRACE("Magic is %c%c%c%c%c%c%c%c",
+	      isprint(buf[0]) ? buf[0] : '.',
+	      isprint(buf[1]) ? buf[1] : '.',
+	      isprint(buf[2]) ? buf[2] : '.',
+	      isprint(buf[3]) ? buf[3] : '.',
+	      isprint(buf[4]) ? buf[4] : '.',
+	      isprint(buf[5]) ? buf[5] : '.',
+	      isprint(buf[6]) ? buf[6] : '.',
+	      isprint(buf[7]) ? buf[7] : '.');
+	TRACE("Magic is 0x%" PRIx64, magic);
+	TRACE("Size is %" PRIu64, size);
+
+	if (memcmp(buf, "NBDMAGIC", 8) != 0) {
+		LOG("Invalid magic received");
+		errno = EINVAL;
+		return -1;
+	}
+
+	TRACE("Checking magic");
+
+	if (magic != 0x00420281861253LL) {
+		LOG("Bad magic received");
+		errno = EINVAL;
+		return -1;
+	}
+
+	TRACE("Setting block size to %lu", (unsigned long)blocksize);
+
+	if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
+		int serrno = errno;
+		LOG("Failed setting NBD block size");
+		errno = serrno;
+		return -1;
+	}
+
+	TRACE("Setting size to %llu block(s)",
+	      (unsigned long long)(size / blocksize));
+
+	if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) == -1) {
+		int serrno = errno;
+		LOG("Failed setting size (in blocks)");
+		errno = serrno;
+		return -1;
+	}
+
+	TRACE("Clearing NBD socket");
+
+	if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
+		int serrno = errno;
+		LOG("Failed clearing NBD socket");
+		errno = serrno;
+		return -1;
+	}
+
+	TRACE("Setting NBD socket");
+
+	if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
+		int serrno = errno;
+		LOG("Failed to set NBD socket");
+		errno = serrno;
+		return -1;
+	}
+
+	TRACE("Negotiation ended");
+
+	return 0;
+}
+
+int nbd_disconnect(int fd)
+{
+	ioctl(fd, NBD_CLEAR_QUE);
+	ioctl(fd, NBD_DISCONNECT);
+	ioctl(fd, NBD_CLEAR_SOCK);
+	return 0;
+}
+
+int nbd_client(int fd, int csock)
+{
+	int ret;
+	int serrno;
+
+	TRACE("Doing NBD loop");
+
+	ret = ioctl(fd, NBD_DO_IT);
+	serrno = errno;
+
+	TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
+
+	TRACE("Clearing NBD queue");
+	ioctl(fd, NBD_CLEAR_QUE);
+
+	TRACE("Clearing NBD socket");
+	ioctl(fd, NBD_CLEAR_SOCK);
+
+	errno = serrno;
+	return ret;
+}
+
+int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly)
+{
+#ifndef _REENTRANT
+	static uint8_t data[1024 * 1024]; // keep this off of the stack
+#else
+	uint8_t data[1024 * 1024];
+#endif
+	uint8_t buf[4 + 4 + 8 + 8 + 4];
+	uint32_t magic;
+	uint32_t type;
+	uint64_t from;
+	uint32_t len;
+
+	TRACE("Reading request.");
+
+	if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+		LOG("read failed");
+		errno = EINVAL;
+		return -1;
+	}
+
+	/* Request
+	  [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
+	  [ 4 ..  7]   type    (0 == READ, 1 == WRITE)
+	  [ 8 .. 15]   handle
+	  [16 .. 23]   from
+	  [24 .. 27]   len
+	 */
+
+	magic = be32_to_cpup((uint32_t*)buf);
+	type  = be32_to_cpup((uint32_t*)(buf + 4));
+	from  = be64_to_cpup((uint64_t*)(buf + 16));
+	len   = be32_to_cpup((uint32_t*)(buf + 24));
+
+	TRACE("Got request: "
+	      "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
+	      magic, type, from, len);
+
+
+	if (magic != NBD_REQUEST_MAGIC) {
+		LOG("invalid magic (got 0x%x)", magic);
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (len > sizeof(data)) {
+		LOG("len (%u) is larger than max len (%lu)",
+		    len, sizeof(data));
+		errno = EINVAL;
+		return -1;
+	}
+
+	if ((from + len) < from) {
+		LOG("integer overflow detected! "
+		    "you're probably being attacked");
+		errno = EINVAL;
+		return -1;
+	}
+
+	if ((from + len) > size) {
+	        LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
+		    ", Offset: %" PRIu64 "\n",
+		     from, len, size, dev_offset);
+		LOG("requested operation past EOF--bad client?");
+		errno = EINVAL;
+		return -1;
+	}
+
+	/* Reply
+	 [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
+	 [ 4 ..  7]    error   (0 == no error)
+         [ 7 .. 15]    handle
+	 */
+	cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
+	cpu_to_be32w((uint32_t*)(buf + 4), 0);
+
+	TRACE("Decoding type");
+
+	switch (type) {
+	case 0:
+		TRACE("Request type is READ");
+
+		if (bdrv_read(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
+			LOG("reading from file failed");
+			errno = EINVAL;
+			return -1;
+		}
+		*offset += len;
+
+		TRACE("Read %u byte(s)", len);
+
+		TRACE("Sending OK response");
+
+		if (write_sync(csock, buf, 16) != 16) {
+			LOG("writing to socket failed");
+			errno = EINVAL;
+			return -1;
+		}
+
+		TRACE("Sending data to client");
+
+		if (write_sync(csock, data, len) != len) {
+			LOG("writing to socket failed");
+			errno = EINVAL;
+			return -1;
+		}
+		break;
+	case 1:
+		TRACE("Request type is WRITE");
+
+		TRACE("Reading %u byte(s)", len);
+
+		if (read_sync(csock, data, len) != len) {
+			LOG("reading from socket failed");
+			errno = EINVAL;
+			return -1;
+		}
+
+		if (readonly) {
+			TRACE("Server is read-only, return error");
+
+			cpu_to_be32w((uint32_t*)(buf + 4), 1);
+		} else {
+			TRACE("Writing to device");
+
+			if (bdrv_write(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
+				LOG("writing to file failed");
+				errno = EINVAL;
+				return -1;
+			}
+
+			*offset += len;
+		}
+
+		TRACE("Sending response to client");
+
+		if (write_sync(csock, buf, 16) != 16) {
+			LOG("writing to socket failed");
+			errno = EINVAL;
+			return -1;
+		}
+		break;
+	case 2:
+		TRACE("Request type is DISCONNECT");
+		errno = 0;
+		return 1;
+	default:
+		LOG("invalid request type (%u) received", type);
+		errno = EINVAL;
+		return -1;
+	}
+
+	TRACE("Request/Reply complete");
+
+	return 0;
+}