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-rw-r--r--nbd.c500
1 files changed, 500 insertions, 0 deletions
diff --git a/nbd.c b/nbd.c
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index 000000000..fcf033929
--- /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;
+}