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qemu/nbd.c

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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, 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>
#ifdef __sun__
#include <sys/ioccom.h>
#endif
#include <ctype.h>
#include <inttypes.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#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)
/* 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) 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 = read(fd, buffer + offset, size - offset);
} else {
len = write(fd, buffer + offset, size - offset);
}
/* 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;
}
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;
}
int unix_socket_incoming(const char *path)
{
int s;
struct sockaddr_un addr;
int serrno;
s = socket(PF_UNIX, SOCK_STREAM, 0);
if (s == -1) {
return -1;
}
memset(&addr, 0, sizeof(addr));
addr.sun_family = AF_UNIX;
pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
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;
}
int unix_socket_outgoing(const char *path)
{
int s;
struct sockaddr_un addr;
int serrno;
s = socket(PF_UNIX, SOCK_STREAM, 0);
if (s == -1) {
return -1;
}
memset(&addr, 0, sizeof(addr));
addr.sun_family = AF_UNIX;
pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -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 csock, off_t *size, size_t *blocksize)
{
char buf[8 + 8 + 8 + 128];
uint64_t magic;
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;
}
return 0;
}
int nbd_init(int fd, int csock, 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 %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_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;
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[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;
}
/* 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 ((request.from + request.len) > size) {
LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
", Offset: %" PRIu64 "\n",
request.from, request.len, 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,
request.len / 512) == -1) {
LOG("reading from file failed");
errno = EINVAL;
return -1;
}
*offset += request.len;
TRACE("Read %u byte(s)", request.len);
if (nbd_send_reply(csock, &reply) == -1)
return -1;
TRACE("Sending data to client");
if (write_sync(csock, data, request.len) != request.len) {
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 (readonly) {
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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