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qemu/nbd.c
Paolo Bonzini 973b3d0a7b nbd: support NBD_SET_FLAGS ioctl 
The nbd kernel module cannot enable DISCARD requests unless it is
informed about it.  The flags field in the header is used for this,
and this patch adds support for it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-19 11:34:33 +02:00

696 lines
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/*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include "nbd.h"
#include "block.h"
#include <errno.h>
#include <string.h>
#ifndef _WIN32
#include <sys/ioctl.h>
#endif
#if defined(__sun__) || defined(__HAIKU__)
#include <sys/ioccom.h>
#endif
#include <ctype.h>
#include <inttypes.h>
#ifdef __linux__
#include <linux/fs.h>
#endif
#include "qemu_socket.h"
//#define DEBUG_NBD
#ifdef DEBUG_NBD
#define TRACE(msg, ...) do { \
LOG(msg, ## __VA_ARGS__); \
} while(0)
#else
#define TRACE(msg, ...) \
do { } while (0)
#endif
#define LOG(msg, ...) do { \
fprintf(stderr, "%s:%s():L%d: " msg "\n", \
__FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
} while(0)
/* This is all part of the "official" NBD API */
#define NBD_REPLY_SIZE (4 + 4 + 8)
#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)
#define NBD_SET_TIMEOUT _IO(0xab, 9)
#define NBD_SET_FLAGS _IO(0xab, 10)
#define NBD_OPT_EXPORT_NAME (1 << 0)
/* That's all folks */
#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)
size_t nbd_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 = qemu_recv(fd, buffer + offset, size - offset, 0);
} else {
len = send(fd, buffer + offset, size - offset, 0);
}
if (len == -1)
errno = socket_error();
/* recoverable error */
if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
continue;
}
/* eof */
if (len == 0) {
break;
}
/* unrecoverable error */
if (len == -1) {
return 0;
}
offset += len;
}
return offset;
}
static void combine_addr(char *buf, size_t len, const char* address,
uint16_t port)
{
/* If the address-part contains a colon, it's an IPv6 IP so needs [] */
if (strstr(address, ":")) {
snprintf(buf, len, "[%s]:%u", address, port);
} else {
snprintf(buf, len, "%s:%u", address, port);
}
}
int tcp_socket_outgoing(const char *address, uint16_t port)
{
char address_and_port[128];
combine_addr(address_and_port, 128, address, port);
return tcp_socket_outgoing_spec(address_and_port);
}
int tcp_socket_outgoing_spec(const char *address_and_port)
{
return inet_connect(address_and_port, SOCK_STREAM);
}
int tcp_socket_incoming(const char *address, uint16_t port)
{
char address_and_port[128];
combine_addr(address_and_port, 128, address, port);
return tcp_socket_incoming_spec(address_and_port);
}
int tcp_socket_incoming_spec(const char *address_and_port)
{
char *ostr = NULL;
int olen = 0;
return inet_listen(address_and_port, ostr, olen, SOCK_STREAM, 0);
}
int unix_socket_incoming(const char *path)
{
char *ostr = NULL;
int olen = 0;
return unix_listen(path, ostr, olen);
}
int unix_socket_outgoing(const char *path)
{
return unix_connect(path);
}
/* Basic flow
Server Client
Negotiate
Request
Response
Request
Response
...
...
Request (type == 2)
*/
int nbd_negotiate(int csock, off_t size, uint32_t flags)
{
char buf[8 + 8 + 8 + 128];
/* Negotiate
[ 0 .. 7] passwd ("NBDMAGIC")
[ 8 .. 15] magic (0x00420281861253)
[16 .. 23] size
[24 .. 27] flags
[28 .. 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);
cpu_to_be32w((uint32_t*)(buf + 24), flags | NBD_FLAG_HAS_FLAGS);
memset(buf + 28, 0, 124);
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 csock, const char *name, uint32_t *flags,
off_t *size, size_t *blocksize)
{
char buf[256];
uint64_t magic, s;
uint16_t tmp;
TRACE("Receiving negotation.");
if (read_sync(csock, buf, 8) != 8) {
LOG("read failed");
errno = EINVAL;
return -1;
}
buf[8] = '\0';
if (strlen(buf) == 0) {
LOG("server connection closed");
errno = EINVAL;
return -1;
}
TRACE("Magic is %c%c%c%c%c%c%c%c",
qemu_isprint(buf[0]) ? buf[0] : '.',
qemu_isprint(buf[1]) ? buf[1] : '.',
qemu_isprint(buf[2]) ? buf[2] : '.',
qemu_isprint(buf[3]) ? buf[3] : '.',
qemu_isprint(buf[4]) ? buf[4] : '.',
qemu_isprint(buf[5]) ? buf[5] : '.',
qemu_isprint(buf[6]) ? buf[6] : '.',
qemu_isprint(buf[7]) ? buf[7] : '.');
if (memcmp(buf, "NBDMAGIC", 8) != 0) {
LOG("Invalid magic received");
errno = EINVAL;
return -1;
}
if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("read failed");
errno = EINVAL;
return -1;
}
magic = be64_to_cpu(magic);
TRACE("Magic is 0x%" PRIx64, magic);
if (name) {
uint32_t reserved = 0;
uint32_t opt;
uint32_t namesize;
TRACE("Checking magic (opts_magic)");
if (magic != 0x49484156454F5054LL) {
LOG("Bad magic received");
errno = EINVAL;
return -1;
}
if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
LOG("flags read failed");
errno = EINVAL;
return -1;
}
*flags = be16_to_cpu(tmp) << 16;
/* reserved for future use */
if (write_sync(csock, &reserved, sizeof(reserved)) !=
sizeof(reserved)) {
LOG("write failed (reserved)");
errno = EINVAL;
return -1;
}
/* write the export name */
magic = cpu_to_be64(magic);
if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("write failed (magic)");
errno = EINVAL;
return -1;
}
opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
LOG("write failed (opt)");
errno = EINVAL;
return -1;
}
namesize = cpu_to_be32(strlen(name));
if (write_sync(csock, &namesize, sizeof(namesize)) !=
sizeof(namesize)) {
LOG("write failed (namesize)");
errno = EINVAL;
return -1;
}
if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) {
LOG("write failed (name)");
errno = EINVAL;
return -1;
}
} else {
TRACE("Checking magic (cli_magic)");
if (magic != 0x00420281861253LL) {
LOG("Bad magic received");
errno = EINVAL;
return -1;
}
}
if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) {
LOG("read failed");
errno = EINVAL;
return -1;
}
*size = be64_to_cpu(s);
*blocksize = 1024;
TRACE("Size is %" PRIu64, *size);
if (!name) {
if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) {
LOG("read failed (flags)");
errno = EINVAL;
return -1;
}
*flags = be32_to_cpup(flags);
} else {
if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
LOG("read failed (tmp)");
errno = EINVAL;
return -1;
}
*flags |= be32_to_cpu(tmp);
}
if (read_sync(csock, &buf, 124) != 124) {
LOG("read failed (buf)");
errno = EINVAL;
return -1;
}
return 0;
}
#ifdef __linux__
int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
{
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 %zd block(s)", (size_t)(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;
}
if (flags & NBD_FLAG_READ_ONLY) {
int read_only = 1;
TRACE("Setting readonly attribute");
if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
int serrno = errno;
LOG("Failed setting read-only attribute");
errno = serrno;
return -1;
}
}
if (ioctl(fd, NBD_SET_FLAGS, flags) < 0
&& errno != ENOTTY) {
int serrno = errno;
LOG("Failed setting flags");
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 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;
}
#else
int nbd_init(int fd, int csock, off_t size, size_t blocksize)
{
errno = ENOTSUP;
return -1;
}
int nbd_disconnect(int fd)
{
errno = ENOTSUP;
return -1;
}
int nbd_client(int fd)
{
errno = ENOTSUP;
return -1;
}
#endif
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: "
"{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
request->from, request->len, request->handle, request->type);
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;
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);
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, request->type, request->from, request->len);
if (magic != NBD_REQUEST_MAGIC) {
LOG("invalid magic (got 0x%x)", magic);
errno = EINVAL;
return -1;
}
return 0;
}
int nbd_receive_reply(int csock, struct nbd_reply *reply)
{
uint8_t buf[NBD_REPLY_SIZE];
uint32_t magic;
memset(buf, 0xAA, sizeof(buf));
if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("read failed");
errno = EINVAL;
return -1;
}
/* 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, uint32_t nbdflags, 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 + NBD_REPLY_SIZE > data_size) {
LOG("len (%u) is larger than max len (%u)",
request.len + NBD_REPLY_SIZE, 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 ((request.from + request.len) > size) {
LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
", Offset: %" PRIu64 "\n",
request.from, request.len, (uint64_t)size, dev_offset);
LOG("requested operation past EOF--bad client?");
errno = EINVAL;
return -1;
}
TRACE("Decoding type");
reply.handle = request.handle;
reply.error = 0;
switch (request.type) {
case NBD_CMD_READ:
TRACE("Request type is READ");
if (bdrv_read(bs, (request.from + dev_offset) / 512,
data + NBD_REPLY_SIZE,
request.len / 512) == -1) {
LOG("reading from file failed");
errno = EINVAL;
return -1;
}
*offset += request.len;
TRACE("Read %u byte(s)", request.len);
/* Reply
[ 0 .. 3] magic (NBD_REPLY_MAGIC)
[ 4 .. 7] error (0 == no error)
[ 7 .. 15] handle
*/
cpu_to_be32w((uint32_t*)data, NBD_REPLY_MAGIC);
cpu_to_be32w((uint32_t*)(data + 4), reply.error);
cpu_to_be64w((uint64_t*)(data + 8), reply.handle);
TRACE("Sending data to client");
if (write_sync(csock, data,
request.len + NBD_REPLY_SIZE) !=
request.len + NBD_REPLY_SIZE) {
LOG("writing to socket failed");
errno = EINVAL;
return -1;
}
break;
case NBD_CMD_WRITE:
TRACE("Request type is WRITE");
TRACE("Reading %u byte(s)", request.len);
if (read_sync(csock, data, request.len) != request.len) {
LOG("reading from socket failed");
errno = EINVAL;
return -1;
}
if (nbdflags & NBD_FLAG_READ_ONLY) {
TRACE("Server is read-only, return error");
reply.error = 1;
} else {
TRACE("Writing to device");
if (bdrv_write(bs, (request.from + dev_offset) / 512,
data, request.len / 512) == -1) {
LOG("writing to file failed");
errno = EINVAL;
return -1;
}
*offset += request.len;
}
if (nbd_send_reply(csock, &reply) == -1)
return -1;
break;
case NBD_CMD_DISC:
TRACE("Request type is DISCONNECT");
errno = 0;
return 1;
default:
LOG("invalid request type (%u) received", request.type);
errno = EINVAL;
return -1;
}
TRACE("Request/Reply complete");
return 0;
}
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