Allow QEMU to connect directly to an NBD server, by Laurent Vivier.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4838 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/nbd.c b/nbd.c
index 49ee7df..306d1fa 100644
--- a/nbd.c
+++ b/nbd.c
@@ -1,4 +1,4 @@
-/*\
+/*
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device
@@ -15,7 +15,7 @@
* 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"
@@ -31,17 +31,21 @@
#include <arpa/inet.h>
#include <netdb.h>
+#if defined(QEMU_NBD)
extern int verbose;
+#else
+static int verbose = 0;
+#endif
+
+#define TRACE(msg, ...) do { \
+ if (verbose) LOG(msg, ## __VA_ARGS__); \
+} while(0)
#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
@@ -59,10 +63,10 @@
/* 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)
+#define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
+#define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
-static size_t wr_sync(int fd, void *buffer, size_t size, bool do_read)
+size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
{
size_t offset = 0;
@@ -76,7 +80,7 @@
}
/* recoverable error */
- if (len == -1 && errno == EAGAIN) {
+ if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
continue;
}
@@ -96,7 +100,7 @@
return offset;
}
-static int tcp_socket_outgoing(const char *address, uint16_t port)
+int tcp_socket_outgoing(const char *address, uint16_t port)
{
int s;
struct in_addr in;
@@ -404,16 +408,31 @@
return ret;
}
-int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
- off_t *offset, bool readonly, uint8_t *data, int data_size)
+int nbd_send_request(int csock, struct nbd_request *request)
+{
+ uint8_t buf[4 + 4 + 8 + 8 + 4];
+
+ cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
+ cpu_to_be32w((uint32_t*)(buf + 4), request->type);
+ cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
+ cpu_to_be64w((uint64_t*)(buf + 16), request->from);
+ cpu_to_be32w((uint32_t*)(buf + 24), request->len);
+
+ TRACE("Sending request to client");
+
+ if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+ LOG("writing to socket failed");
+ errno = EINVAL;
+ return -1;
+ }
+ return 0;
+}
+
+
+static int nbd_receive_request(int csock, struct nbd_request *request)
{
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");
@@ -422,97 +441,158 @@
}
/* Request
- [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
- [ 4 .. 7] type (0 == READ, 1 == WRITE)
- [ 8 .. 15] handle
- [16 .. 23] from
- [24 .. 27] len
+ [ 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));
+ request->type = be32_to_cpup((uint32_t*)(buf + 4));
+ request->handle = be64_to_cpup((uint64_t*)(buf + 8));
+ request->from = be64_to_cpup((uint64_t*)(buf + 16));
+ request->len = be32_to_cpup((uint32_t*)(buf + 24));
TRACE("Got request: "
"{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
- magic, type, from, len);
-
+ magic, request->type, request->from, request->len);
if (magic != NBD_REQUEST_MAGIC) {
LOG("invalid magic (got 0x%x)", magic);
errno = EINVAL;
return -1;
}
+}
- if (len > data_size) {
- LOG("len (%u) is larger than max len (%u)",
- len, data_size);
+int nbd_receive_reply(int csock, struct nbd_reply *reply)
+{
+ uint8_t buf[4 + 4 + 8];
+ uint32_t magic;
+
+ memset(buf, 0xAA, sizeof(buf));
+
+ if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+ LOG("read failed");
errno = EINVAL;
return -1;
}
- if ((from + len) < from) {
+ /* Reply
+ [ 0 .. 3] magic (NBD_REPLY_MAGIC)
+ [ 4 .. 7] error (0 == no error)
+ [ 7 .. 15] handle
+ */
+
+ magic = be32_to_cpup((uint32_t*)buf);
+ reply->error = be32_to_cpup((uint32_t*)(buf + 4));
+ reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
+
+ TRACE("Got reply: "
+ "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
+ magic, reply->error, reply->handle);
+
+ if (magic != NBD_REPLY_MAGIC) {
+ LOG("invalid magic (got 0x%x)", magic);
+ errno = EINVAL;
+ return -1;
+ }
+ return 0;
+}
+
+static int nbd_send_reply(int csock, struct nbd_reply *reply)
+{
+ uint8_t buf[4 + 4 + 8];
+
+ /* 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), reply->error);
+ cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
+
+ TRACE("Sending response to client");
+
+ if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+ LOG("writing to socket failed");
+ errno = EINVAL;
+ return -1;
+ }
+ return 0;
+}
+
+int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
+ off_t *offset, bool readonly, uint8_t *data, int data_size)
+{
+ struct nbd_request request;
+ struct nbd_reply reply;
+
+ TRACE("Reading request.");
+
+ if (nbd_receive_request(csock, &request) == -1)
+ return -1;
+
+ if (request.len > data_size) {
+ LOG("len (%u) is larger than max len (%u)",
+ request.len, data_size);
+ errno = EINVAL;
+ return -1;
+ }
+
+ if ((request.from + request.len) < request.from) {
LOG("integer overflow detected! "
"you're probably being attacked");
errno = EINVAL;
return -1;
}
- if ((from + len) > size) {
+ if ((request.from + request.len) > size) {
LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
", Offset: %" PRIu64 "\n",
- from, len, size, dev_offset);
+ request.from, request.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:
+ reply.handle = request.handle;
+ reply.error = 0;
+
+ switch (request.type) {
+ case NBD_CMD_READ:
TRACE("Request type is READ");
- if (bdrv_read(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
+ if (bdrv_read(bs, (request.from + dev_offset) / 512, data,
+ request.len / 512) == -1) {
LOG("reading from file failed");
errno = EINVAL;
return -1;
}
- *offset += len;
+ *offset += request.len;
- TRACE("Read %u byte(s)", len);
+ TRACE("Read %u byte(s)", request.len);
- TRACE("Sending OK response");
-
- if (write_sync(csock, buf, 16) != 16) {
- LOG("writing to socket failed");
- errno = EINVAL;
+ if (nbd_send_reply(csock, &reply) == -1)
return -1;
- }
TRACE("Sending data to client");
- if (write_sync(csock, data, len) != len) {
+ if (write_sync(csock, data, request.len) != request.len) {
LOG("writing to socket failed");
errno = EINVAL;
return -1;
}
break;
- case 1:
+ case NBD_CMD_WRITE:
TRACE("Request type is WRITE");
- TRACE("Reading %u byte(s)", len);
+ TRACE("Reading %u byte(s)", request.len);
- if (read_sync(csock, data, len) != len) {
+ if (read_sync(csock, data, request.len) != request.len) {
LOG("reading from socket failed");
errno = EINVAL;
return -1;
@@ -520,34 +600,29 @@
if (readonly) {
TRACE("Server is read-only, return error");
-
- cpu_to_be32w((uint32_t*)(buf + 4), 1);
+ reply.error = 1;
} else {
TRACE("Writing to device");
- if (bdrv_write(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
+ if (bdrv_write(bs, (request.from + dev_offset) / 512,
+ data, request.len / 512) == -1) {
LOG("writing to file failed");
errno = EINVAL;
return -1;
}
- *offset += len;
+ *offset += request.len;
}
- TRACE("Sending response to client");
-
- if (write_sync(csock, buf, 16) != 16) {
- LOG("writing to socket failed");
- errno = EINVAL;
+ if (nbd_send_reply(csock, &reply) == -1)
return -1;
- }
break;
- case 2:
+ case NBD_CMD_DISC:
TRACE("Request type is DISCONNECT");
errno = 0;
return 1;
default:
- LOG("invalid request type (%u) received", type);
+ LOG("invalid request type (%u) received", request.type);
errno = EINVAL;
return -1;
}
