+++ /dev/null
-/*
- * 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 "block/nbd.h"
-#include "sysemu/block-backend.h"
-
-#include "block/coroutine.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/sockets.h"
-#include "qemu/queue.h"
-#include "qemu/main-loop.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.
- *
- * The most up-to-date documentation is available at:
- * https://github.com/yoe/nbd/blob/master/doc/proto.txt
- */
-
-#define NBD_REQUEST_SIZE (4 + 4 + 8 + 8 + 4)
-#define NBD_REPLY_SIZE (4 + 4 + 8)
-#define NBD_REQUEST_MAGIC 0x25609513
-#define NBD_REPLY_MAGIC 0x67446698
-#define NBD_OPTS_MAGIC 0x49484156454F5054LL
-#define NBD_CLIENT_MAGIC 0x0000420281861253LL
-#define NBD_REP_MAGIC 0x3e889045565a9LL
-
-#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)
-#define NBD_OPT_ABORT (2)
-#define NBD_OPT_LIST (3)
-
-/* NBD errors are based on errno numbers, so there is a 1:1 mapping,
- * but only a limited set of errno values is specified in the protocol.
- * Everything else is squashed to EINVAL.
- */
-#define NBD_SUCCESS 0
-#define NBD_EPERM 1
-#define NBD_EIO 5
-#define NBD_ENOMEM 12
-#define NBD_EINVAL 22
-#define NBD_ENOSPC 28
-
-static int system_errno_to_nbd_errno(int err)
-{
- switch (err) {
- case 0:
- return NBD_SUCCESS;
- case EPERM:
- return NBD_EPERM;
- case EIO:
- return NBD_EIO;
- case ENOMEM:
- return NBD_ENOMEM;
-#ifdef EDQUOT
- case EDQUOT:
-#endif
- case EFBIG:
- case ENOSPC:
- return NBD_ENOSPC;
- case EINVAL:
- default:
- return NBD_EINVAL;
- }
-}
-
-static int nbd_errno_to_system_errno(int err)
-{
- switch (err) {
- case NBD_SUCCESS:
- return 0;
- case NBD_EPERM:
- return EPERM;
- case NBD_EIO:
- return EIO;
- case NBD_ENOMEM:
- return ENOMEM;
- case NBD_ENOSPC:
- return ENOSPC;
- case NBD_EINVAL:
- default:
- return EINVAL;
- }
-}
-
-/* Definitions for opaque data types */
-
-typedef struct NBDRequest NBDRequest;
-
-struct NBDRequest {
- QSIMPLEQ_ENTRY(NBDRequest) entry;
- NBDClient *client;
- uint8_t *data;
-};
-
-struct NBDExport {
- int refcount;
- void (*close)(NBDExport *exp);
-
- BlockBackend *blk;
- char *name;
- off_t dev_offset;
- off_t size;
- uint32_t nbdflags;
- QTAILQ_HEAD(, NBDClient) clients;
- QTAILQ_ENTRY(NBDExport) next;
-
- AioContext *ctx;
-};
-
-static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
-
-struct NBDClient {
- int refcount;
- void (*close)(NBDClient *client);
-
- NBDExport *exp;
- int sock;
-
- Coroutine *recv_coroutine;
-
- CoMutex send_lock;
- Coroutine *send_coroutine;
-
- bool can_read;
-
- QTAILQ_ENTRY(NBDClient) next;
- int nb_requests;
- bool closing;
-};
-
-/* That's all folks */
-
-static void nbd_set_handlers(NBDClient *client);
-static void nbd_unset_handlers(NBDClient *client);
-static void nbd_update_can_read(NBDClient *client);
-
-ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
-{
- size_t offset = 0;
- int err;
-
- if (qemu_in_coroutine()) {
- if (do_read) {
- return qemu_co_recv(fd, buffer, size);
- } else {
- return qemu_co_send(fd, buffer, size);
- }
- }
-
- 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 < 0) {
- err = socket_error();
-
- /* recoverable error */
- if (err == EINTR || (offset > 0 && (err == EAGAIN || err == EWOULDBLOCK))) {
- continue;
- }
-
- /* unrecoverable error */
- return -err;
- }
-
- /* eof */
- if (len == 0) {
- break;
- }
-
- offset += len;
- }
-
- return offset;
-}
-
-static ssize_t read_sync(int fd, void *buffer, size_t size)
-{
- /* Sockets are kept in blocking mode in the negotiation phase. After
- * that, a non-readable socket simply means that another thread stole
- * our request/reply. Synchronization is done with recv_coroutine, so
- * that this is coroutine-safe.
- */
- return nbd_wr_sync(fd, buffer, size, true);
-}
-
-static ssize_t drop_sync(int fd, size_t size)
-{
- ssize_t ret, dropped = size;
- uint8_t *buffer = g_malloc(MIN(65536, size));
-
- while (size > 0) {
- ret = read_sync(fd, buffer, MIN(65536, size));
- if (ret < 0) {
- g_free(buffer);
- return ret;
- }
-
- assert(ret <= size);
- size -= ret;
- }
-
- g_free(buffer);
- return dropped;
-}
-
-static ssize_t write_sync(int fd, void *buffer, size_t size)
-{
- int ret;
- do {
- /* For writes, we do expect the socket to be writable. */
- ret = nbd_wr_sync(fd, buffer, size, false);
- } while (ret == -EAGAIN);
- return ret;
-}
-
-/* Basic flow for negotiation
-
- Server Client
- Negotiate
-
- or
-
- Server Client
- Negotiate #1
- Option
- Negotiate #2
-
- ----
-
- followed by
-
- Server Client
- Request
- Response
- Request
- Response
- ...
- ...
- Request (type == 2)
-
-*/
-
-static int nbd_send_rep(int csock, uint32_t type, uint32_t opt)
-{
- uint64_t magic;
- uint32_t len;
-
- magic = cpu_to_be64(NBD_REP_MAGIC);
- if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
- LOG("write failed (rep magic)");
- return -EINVAL;
- }
- opt = cpu_to_be32(opt);
- if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
- LOG("write failed (rep opt)");
- return -EINVAL;
- }
- type = cpu_to_be32(type);
- if (write_sync(csock, &type, sizeof(type)) != sizeof(type)) {
- LOG("write failed (rep type)");
- return -EINVAL;
- }
- len = cpu_to_be32(0);
- if (write_sync(csock, &len, sizeof(len)) != sizeof(len)) {
- LOG("write failed (rep data length)");
- return -EINVAL;
- }
- return 0;
-}
-
-static int nbd_send_rep_list(int csock, NBDExport *exp)
-{
- uint64_t magic, name_len;
- uint32_t opt, type, len;
-
- name_len = strlen(exp->name);
- magic = cpu_to_be64(NBD_REP_MAGIC);
- if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
- LOG("write failed (magic)");
- return -EINVAL;
- }
- opt = cpu_to_be32(NBD_OPT_LIST);
- if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
- LOG("write failed (opt)");
- return -EINVAL;
- }
- type = cpu_to_be32(NBD_REP_SERVER);
- if (write_sync(csock, &type, sizeof(type)) != sizeof(type)) {
- LOG("write failed (reply type)");
- return -EINVAL;
- }
- len = cpu_to_be32(name_len + sizeof(len));
- if (write_sync(csock, &len, sizeof(len)) != sizeof(len)) {
- LOG("write failed (length)");
- return -EINVAL;
- }
- len = cpu_to_be32(name_len);
- if (write_sync(csock, &len, sizeof(len)) != sizeof(len)) {
- LOG("write failed (length)");
- return -EINVAL;
- }
- if (write_sync(csock, exp->name, name_len) != name_len) {
- LOG("write failed (buffer)");
- return -EINVAL;
- }
- return 0;
-}
-
-static int nbd_handle_list(NBDClient *client, uint32_t length)
-{
- int csock;
- NBDExport *exp;
-
- csock = client->sock;
- if (length) {
- if (drop_sync(csock, length) != length) {
- return -EIO;
- }
- return nbd_send_rep(csock, NBD_REP_ERR_INVALID, NBD_OPT_LIST);
- }
-
- /* For each export, send a NBD_REP_SERVER reply. */
- QTAILQ_FOREACH(exp, &exports, next) {
- if (nbd_send_rep_list(csock, exp)) {
- return -EINVAL;
- }
- }
- /* Finish with a NBD_REP_ACK. */
- return nbd_send_rep(csock, NBD_REP_ACK, NBD_OPT_LIST);
-}
-
-static int nbd_handle_export_name(NBDClient *client, uint32_t length)
-{
- int rc = -EINVAL, csock = client->sock;
- char name[256];
-
- /* Client sends:
- [20 .. xx] export name (length bytes)
- */
- TRACE("Checking length");
- if (length > 255) {
- LOG("Bad length received");
- goto fail;
- }
- if (read_sync(csock, name, length) != length) {
- LOG("read failed");
- goto fail;
- }
- name[length] = '\0';
-
- client->exp = nbd_export_find(name);
- if (!client->exp) {
- LOG("export not found");
- goto fail;
- }
-
- QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
- nbd_export_get(client->exp);
- rc = 0;
-fail:
- return rc;
-}
-
-static int nbd_receive_options(NBDClient *client)
-{
- int csock = client->sock;
- uint32_t flags;
-
- /* Client sends:
- [ 0 .. 3] client flags
-
- [ 0 .. 7] NBD_OPTS_MAGIC
- [ 8 .. 11] NBD option
- [12 .. 15] Data length
- ... Rest of request
-
- [ 0 .. 7] NBD_OPTS_MAGIC
- [ 8 .. 11] Second NBD option
- [12 .. 15] Data length
- ... Rest of request
- */
-
- if (read_sync(csock, &flags, sizeof(flags)) != sizeof(flags)) {
- LOG("read failed");
- return -EIO;
- }
- TRACE("Checking client flags");
- be32_to_cpus(&flags);
- if (flags != 0 && flags != NBD_FLAG_C_FIXED_NEWSTYLE) {
- LOG("Bad client flags received");
- return -EIO;
- }
-
- while (1) {
- int ret;
- uint32_t tmp, length;
- uint64_t magic;
-
- if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
- LOG("read failed");
- return -EINVAL;
- }
- TRACE("Checking opts magic");
- if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {
- LOG("Bad magic received");
- return -EINVAL;
- }
-
- if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
- LOG("read failed");
- return -EINVAL;
- }
-
- if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) {
- LOG("read failed");
- return -EINVAL;
- }
- length = be32_to_cpu(length);
-
- TRACE("Checking option");
- switch (be32_to_cpu(tmp)) {
- case NBD_OPT_LIST:
- ret = nbd_handle_list(client, length);
- if (ret < 0) {
- return ret;
- }
- break;
-
- case NBD_OPT_ABORT:
- return -EINVAL;
-
- case NBD_OPT_EXPORT_NAME:
- return nbd_handle_export_name(client, length);
-
- default:
- tmp = be32_to_cpu(tmp);
- LOG("Unsupported option 0x%x", tmp);
- nbd_send_rep(client->sock, NBD_REP_ERR_UNSUP, tmp);
- return -EINVAL;
- }
- }
-}
-
-static int nbd_send_negotiate(NBDClient *client)
-{
- int csock = client->sock;
- char buf[8 + 8 + 8 + 128];
- int rc;
- const int myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
- NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);
-
- /* Negotiation header without options:
- [ 0 .. 7] passwd ("NBDMAGIC")
- [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
- [16 .. 23] size
- [24 .. 25] server flags (0)
- [26 .. 27] export flags
- [28 .. 151] reserved (0)
-
- Negotiation header with options, part 1:
- [ 0 .. 7] passwd ("NBDMAGIC")
- [ 8 .. 15] magic (NBD_OPTS_MAGIC)
- [16 .. 17] server flags (0)
-
- part 2 (after options are sent):
- [18 .. 25] size
- [26 .. 27] export flags
- [28 .. 151] reserved (0)
- */
-
- qemu_set_block(csock);
- rc = -EINVAL;
-
- TRACE("Beginning negotiation.");
- memset(buf, 0, sizeof(buf));
- memcpy(buf, "NBDMAGIC", 8);
- if (client->exp) {
- assert ((client->exp->nbdflags & ~65535) == 0);
- cpu_to_be64w((uint64_t*)(buf + 8), NBD_CLIENT_MAGIC);
- cpu_to_be64w((uint64_t*)(buf + 16), client->exp->size);
- cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags);
- } else {
- cpu_to_be64w((uint64_t*)(buf + 8), NBD_OPTS_MAGIC);
- cpu_to_be16w((uint16_t *)(buf + 16), NBD_FLAG_FIXED_NEWSTYLE);
- }
-
- if (client->exp) {
- if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
- LOG("write failed");
- goto fail;
- }
- } else {
- if (write_sync(csock, buf, 18) != 18) {
- LOG("write failed");
- goto fail;
- }
- rc = nbd_receive_options(client);
- if (rc != 0) {
- LOG("option negotiation failed");
- goto fail;
- }
-
- assert ((client->exp->nbdflags & ~65535) == 0);
- cpu_to_be64w((uint64_t*)(buf + 18), client->exp->size);
- cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags);
- if (write_sync(csock, buf + 18, sizeof(buf) - 18) != sizeof(buf) - 18) {
- LOG("write failed");
- goto fail;
- }
- }
-
- TRACE("Negotiation succeeded.");
- rc = 0;
-fail:
- qemu_set_nonblock(csock);
- return rc;
-}
-
-int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
- off_t *size, Error **errp)
-{
- char buf[256];
- uint64_t magic, s;
- uint16_t tmp;
- int rc;
-
- TRACE("Receiving negotiation.");
-
- rc = -EINVAL;
-
- if (read_sync(csock, buf, 8) != 8) {
- error_setg(errp, "Failed to read data");
- goto fail;
- }
-
- buf[8] = '\0';
- if (strlen(buf) == 0) {
- error_setg(errp, "Server connection closed unexpectedly");
- goto fail;
- }
-
- 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) {
- error_setg(errp, "Invalid magic received");
- goto fail;
- }
-
- if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
- error_setg(errp, "Failed to read magic");
- goto fail;
- }
- 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 != NBD_OPTS_MAGIC) {
- if (magic == NBD_CLIENT_MAGIC) {
- error_setg(errp, "Server does not support export names");
- } else {
- error_setg(errp, "Bad magic received");
- }
- goto fail;
- }
- if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
- error_setg(errp, "Failed to read server flags");
- goto fail;
- }
- *flags = be16_to_cpu(tmp) << 16;
- /* reserved for future use */
- if (write_sync(csock, &reserved, sizeof(reserved)) !=
- sizeof(reserved)) {
- error_setg(errp, "Failed to read reserved field");
- goto fail;
- }
- /* write the export name */
- magic = cpu_to_be64(magic);
- if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
- error_setg(errp, "Failed to send export name magic");
- goto fail;
- }
- opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
- if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
- error_setg(errp, "Failed to send export name option number");
- goto fail;
- }
- namesize = cpu_to_be32(strlen(name));
- if (write_sync(csock, &namesize, sizeof(namesize)) !=
- sizeof(namesize)) {
- error_setg(errp, "Failed to send export name length");
- goto fail;
- }
- if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) {
- error_setg(errp, "Failed to send export name");
- goto fail;
- }
- } else {
- TRACE("Checking magic (cli_magic)");
-
- if (magic != NBD_CLIENT_MAGIC) {
- if (magic == NBD_OPTS_MAGIC) {
- error_setg(errp, "Server requires an export name");
- } else {
- error_setg(errp, "Bad magic received");
- }
- goto fail;
- }
- }
-
- if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) {
- error_setg(errp, "Failed to read export length");
- goto fail;
- }
- *size = be64_to_cpu(s);
- TRACE("Size is %" PRIu64, *size);
-
- if (!name) {
- if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) {
- error_setg(errp, "Failed to read export flags");
- goto fail;
- }
- *flags = be32_to_cpup(flags);
- } else {
- if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
- error_setg(errp, "Failed to read export flags");
- goto fail;
- }
- *flags |= be16_to_cpu(tmp);
- }
- if (read_sync(csock, &buf, 124) != 124) {
- error_setg(errp, "Failed to read reserved block");
- goto fail;
- }
- rc = 0;
-
-fail:
- return rc;
-}
-
-#ifdef __linux__
-int nbd_init(int fd, int csock, uint32_t flags, off_t size)
-{
- TRACE("Setting NBD socket");
-
- if (ioctl(fd, NBD_SET_SOCK, csock) < 0) {
- int serrno = errno;
- LOG("Failed to set NBD socket");
- return -serrno;
- }
-
- TRACE("Setting block size to %lu", (unsigned long)BDRV_SECTOR_SIZE);
-
- if (ioctl(fd, NBD_SET_BLKSIZE, (size_t)BDRV_SECTOR_SIZE) < 0) {
- int serrno = errno;
- LOG("Failed setting NBD block size");
- return -serrno;
- }
-
- TRACE("Setting size to %zd block(s)", (size_t)(size / BDRV_SECTOR_SIZE));
-
- if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE)) < 0) {
- int serrno = errno;
- LOG("Failed setting size (in blocks)");
- return -serrno;
- }
-
- if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) {
- if (errno == ENOTTY) {
- int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
- TRACE("Setting readonly attribute");
-
- if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
- int serrno = errno;
- LOG("Failed setting read-only attribute");
- return -serrno;
- }
- } else {
- int serrno = errno;
- LOG("Failed setting flags");
- return -serrno;
- }
- }
-
- 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);
- if (ret < 0 && errno == EPIPE) {
- /* NBD_DO_IT normally returns EPIPE when someone has disconnected
- * the socket via NBD_DISCONNECT. We do not want to return 1 in
- * that case.
- */
- ret = 0;
- }
- 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, uint32_t flags, off_t size)
-{
- return -ENOTSUP;
-}
-
-int nbd_disconnect(int fd)
-{
- return -ENOTSUP;
-}
-
-int nbd_client(int fd)
-{
- return -ENOTSUP;
-}
-#endif
-
-ssize_t nbd_send_request(int csock, struct nbd_request *request)
-{
- uint8_t buf[NBD_REQUEST_SIZE];
- ssize_t ret;
-
- 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);
-
- ret = write_sync(csock, buf, sizeof(buf));
- if (ret < 0) {
- return ret;
- }
-
- if (ret != sizeof(buf)) {
- LOG("writing to socket failed");
- return -EINVAL;
- }
- return 0;
-}
-
-static ssize_t nbd_receive_request(int csock, struct nbd_request *request)
-{
- uint8_t buf[NBD_REQUEST_SIZE];
- uint32_t magic;
- ssize_t ret;
-
- ret = read_sync(csock, buf, sizeof(buf));
- if (ret < 0) {
- return ret;
- }
-
- if (ret != sizeof(buf)) {
- LOG("read failed");
- return -EINVAL;
- }
-
- /* 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);
- return -EINVAL;
- }
- return 0;
-}
-
-ssize_t nbd_receive_reply(int csock, struct nbd_reply *reply)
-{
- uint8_t buf[NBD_REPLY_SIZE];
- uint32_t magic;
- ssize_t ret;
-
- ret = read_sync(csock, buf, sizeof(buf));
- if (ret < 0) {
- return ret;
- }
-
- if (ret != sizeof(buf)) {
- LOG("read failed");
- return -EINVAL;
- }
-
- /* 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));
-
- reply->error = nbd_errno_to_system_errno(reply->error);
-
- 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);
- return -EINVAL;
- }
- return 0;
-}
-
-static ssize_t nbd_send_reply(int csock, struct nbd_reply *reply)
-{
- uint8_t buf[NBD_REPLY_SIZE];
- ssize_t ret;
-
- reply->error = system_errno_to_nbd_errno(reply->error);
-
- /* 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");
-
- ret = write_sync(csock, buf, sizeof(buf));
- if (ret < 0) {
- return ret;
- }
-
- if (ret != sizeof(buf)) {
- LOG("writing to socket failed");
- return -EINVAL;
- }
- return 0;
-}
-
-#define MAX_NBD_REQUESTS 16
-
-void nbd_client_get(NBDClient *client)
-{
- client->refcount++;
-}
-
-void nbd_client_put(NBDClient *client)
-{
- if (--client->refcount == 0) {
- /* The last reference should be dropped by client->close,
- * which is called by client_close.
- */
- assert(client->closing);
-
- nbd_unset_handlers(client);
- close(client->sock);
- client->sock = -1;
- if (client->exp) {
- QTAILQ_REMOVE(&client->exp->clients, client, next);
- nbd_export_put(client->exp);
- }
- g_free(client);
- }
-}
-
-static void client_close(NBDClient *client)
-{
- if (client->closing) {
- return;
- }
-
- client->closing = true;
-
- /* Force requests to finish. They will drop their own references,
- * then we'll close the socket and free the NBDClient.
- */
- shutdown(client->sock, 2);
-
- /* Also tell the client, so that they release their reference. */
- if (client->close) {
- client->close(client);
- }
-}
-
-static NBDRequest *nbd_request_get(NBDClient *client)
-{
- NBDRequest *req;
-
- assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
- client->nb_requests++;
- nbd_update_can_read(client);
-
- req = g_slice_new0(NBDRequest);
- nbd_client_get(client);
- req->client = client;
- return req;
-}
-
-static void nbd_request_put(NBDRequest *req)
-{
- NBDClient *client = req->client;
-
- if (req->data) {
- qemu_vfree(req->data);
- }
- g_slice_free(NBDRequest, req);
-
- client->nb_requests--;
- nbd_update_can_read(client);
- nbd_client_put(client);
-}
-
-static void blk_aio_attached(AioContext *ctx, void *opaque)
-{
- NBDExport *exp = opaque;
- NBDClient *client;
-
- TRACE("Export %s: Attaching clients to AIO context %p\n", exp->name, ctx);
-
- exp->ctx = ctx;
-
- QTAILQ_FOREACH(client, &exp->clients, next) {
- nbd_set_handlers(client);
- }
-}
-
-static void blk_aio_detach(void *opaque)
-{
- NBDExport *exp = opaque;
- NBDClient *client;
-
- TRACE("Export %s: Detaching clients from AIO context %p\n", exp->name, exp->ctx);
-
- QTAILQ_FOREACH(client, &exp->clients, next) {
- nbd_unset_handlers(client);
- }
-
- exp->ctx = NULL;
-}
-
-NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
- uint32_t nbdflags, void (*close)(NBDExport *),
- Error **errp)
-{
- NBDExport *exp = g_malloc0(sizeof(NBDExport));
- exp->refcount = 1;
- QTAILQ_INIT(&exp->clients);
- exp->blk = blk;
- exp->dev_offset = dev_offset;
- exp->nbdflags = nbdflags;
- exp->size = size < 0 ? blk_getlength(blk) : size;
- if (exp->size < 0) {
- error_setg_errno(errp, -exp->size,
- "Failed to determine the NBD export's length");
- goto fail;
- }
- exp->size -= exp->size % BDRV_SECTOR_SIZE;
-
- exp->close = close;
- exp->ctx = blk_get_aio_context(blk);
- blk_ref(blk);
- blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
- /*
- * NBD exports are used for non-shared storage migration. Make sure
- * that BDRV_O_INCOMING is cleared and the image is ready for write
- * access since the export could be available before migration handover.
- */
- blk_invalidate_cache(blk, NULL);
- return exp;
-
-fail:
- g_free(exp);
- return NULL;
-}
-
-NBDExport *nbd_export_find(const char *name)
-{
- NBDExport *exp;
- QTAILQ_FOREACH(exp, &exports, next) {
- if (strcmp(name, exp->name) == 0) {
- return exp;
- }
- }
-
- return NULL;
-}
-
-void nbd_export_set_name(NBDExport *exp, const char *name)
-{
- if (exp->name == name) {
- return;
- }
-
- nbd_export_get(exp);
- if (exp->name != NULL) {
- g_free(exp->name);
- exp->name = NULL;
- QTAILQ_REMOVE(&exports, exp, next);
- nbd_export_put(exp);
- }
- if (name != NULL) {
- nbd_export_get(exp);
- exp->name = g_strdup(name);
- QTAILQ_INSERT_TAIL(&exports, exp, next);
- }
- nbd_export_put(exp);
-}
-
-void nbd_export_close(NBDExport *exp)
-{
- NBDClient *client, *next;
-
- nbd_export_get(exp);
- QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
- client_close(client);
- }
- nbd_export_set_name(exp, NULL);
- nbd_export_put(exp);
- if (exp->blk) {
- blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
- blk_aio_detach, exp);
- blk_unref(exp->blk);
- exp->blk = NULL;
- }
-}
-
-void nbd_export_get(NBDExport *exp)
-{
- assert(exp->refcount > 0);
- exp->refcount++;
-}
-
-void nbd_export_put(NBDExport *exp)
-{
- assert(exp->refcount > 0);
- if (exp->refcount == 1) {
- nbd_export_close(exp);
- }
-
- if (--exp->refcount == 0) {
- assert(exp->name == NULL);
-
- if (exp->close) {
- exp->close(exp);
- }
-
- g_free(exp);
- }
-}
-
-BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
-{
- return exp->blk;
-}
-
-void nbd_export_close_all(void)
-{
- NBDExport *exp, *next;
-
- QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
- nbd_export_close(exp);
- }
-}
-
-static ssize_t nbd_co_send_reply(NBDRequest *req, struct nbd_reply *reply,
- int len)
-{
- NBDClient *client = req->client;
- int csock = client->sock;
- ssize_t rc, ret;
-
- qemu_co_mutex_lock(&client->send_lock);
- client->send_coroutine = qemu_coroutine_self();
- nbd_set_handlers(client);
-
- if (!len) {
- rc = nbd_send_reply(csock, reply);
- } else {
- socket_set_cork(csock, 1);
- rc = nbd_send_reply(csock, reply);
- if (rc >= 0) {
- ret = qemu_co_send(csock, req->data, len);
- if (ret != len) {
- rc = -EIO;
- }
- }
- socket_set_cork(csock, 0);
- }
-
- client->send_coroutine = NULL;
- nbd_set_handlers(client);
- qemu_co_mutex_unlock(&client->send_lock);
- return rc;
-}
-
-static ssize_t nbd_co_receive_request(NBDRequest *req, struct nbd_request *request)
-{
- NBDClient *client = req->client;
- int csock = client->sock;
- uint32_t command;
- ssize_t rc;
-
- client->recv_coroutine = qemu_coroutine_self();
- nbd_update_can_read(client);
-
- rc = nbd_receive_request(csock, request);
- if (rc < 0) {
- if (rc != -EAGAIN) {
- rc = -EIO;
- }
- goto out;
- }
-
- if (request->len > NBD_MAX_BUFFER_SIZE) {
- LOG("len (%u) is larger than max len (%u)",
- request->len, NBD_MAX_BUFFER_SIZE);
- rc = -EINVAL;
- goto out;
- }
-
- if ((request->from + request->len) < request->from) {
- LOG("integer overflow detected! "
- "you're probably being attacked");
- rc = -EINVAL;
- goto out;
- }
-
- TRACE("Decoding type");
-
- command = request->type & NBD_CMD_MASK_COMMAND;
- if (command == NBD_CMD_READ || command == NBD_CMD_WRITE) {
- req->data = blk_blockalign(client->exp->blk, request->len);
- }
- if (command == NBD_CMD_WRITE) {
- TRACE("Reading %u byte(s)", request->len);
-
- if (qemu_co_recv(csock, req->data, request->len) != request->len) {
- LOG("reading from socket failed");
- rc = -EIO;
- goto out;
- }
- }
- rc = 0;
-
-out:
- client->recv_coroutine = NULL;
- nbd_update_can_read(client);
-
- return rc;
-}
-
-static void nbd_trip(void *opaque)
-{
- NBDClient *client = opaque;
- NBDExport *exp = client->exp;
- NBDRequest *req;
- struct nbd_request request;
- struct nbd_reply reply;
- ssize_t ret;
- uint32_t command;
-
- TRACE("Reading request.");
- if (client->closing) {
- return;
- }
-
- req = nbd_request_get(client);
- ret = nbd_co_receive_request(req, &request);
- if (ret == -EAGAIN) {
- goto done;
- }
- if (ret == -EIO) {
- goto out;
- }
-
- reply.handle = request.handle;
- reply.error = 0;
-
- if (ret < 0) {
- reply.error = -ret;
- goto error_reply;
- }
- command = request.type & NBD_CMD_MASK_COMMAND;
- if (command != NBD_CMD_DISC && (request.from + request.len) > exp->size) {
- LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
- ", Offset: %" PRIu64 "\n",
- request.from, request.len,
- (uint64_t)exp->size, (uint64_t)exp->dev_offset);
- LOG("requested operation past EOF--bad client?");
- goto invalid_request;
- }
-
- switch (command) {
- case NBD_CMD_READ:
- TRACE("Request type is READ");
-
- if (request.type & NBD_CMD_FLAG_FUA) {
- ret = blk_co_flush(exp->blk);
- if (ret < 0) {
- LOG("flush failed");
- reply.error = -ret;
- goto error_reply;
- }
- }
-
- ret = blk_read(exp->blk,
- (request.from + exp->dev_offset) / BDRV_SECTOR_SIZE,
- req->data, request.len / BDRV_SECTOR_SIZE);
- if (ret < 0) {
- LOG("reading from file failed");
- reply.error = -ret;
- goto error_reply;
- }
-
- TRACE("Read %u byte(s)", request.len);
- if (nbd_co_send_reply(req, &reply, request.len) < 0)
- goto out;
- break;
- case NBD_CMD_WRITE:
- TRACE("Request type is WRITE");
-
- if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
- TRACE("Server is read-only, return error");
- reply.error = EROFS;
- goto error_reply;
- }
-
- TRACE("Writing to device");
-
- ret = blk_write(exp->blk,
- (request.from + exp->dev_offset) / BDRV_SECTOR_SIZE,
- req->data, request.len / BDRV_SECTOR_SIZE);
- if (ret < 0) {
- LOG("writing to file failed");
- reply.error = -ret;
- goto error_reply;
- }
-
- if (request.type & NBD_CMD_FLAG_FUA) {
- ret = blk_co_flush(exp->blk);
- if (ret < 0) {
- LOG("flush failed");
- reply.error = -ret;
- goto error_reply;
- }
- }
-
- if (nbd_co_send_reply(req, &reply, 0) < 0) {
- goto out;
- }
- break;
- case NBD_CMD_DISC:
- TRACE("Request type is DISCONNECT");
- errno = 0;
- goto out;
- case NBD_CMD_FLUSH:
- TRACE("Request type is FLUSH");
-
- ret = blk_co_flush(exp->blk);
- if (ret < 0) {
- LOG("flush failed");
- reply.error = -ret;
- }
- if (nbd_co_send_reply(req, &reply, 0) < 0) {
- goto out;
- }
- break;
- case NBD_CMD_TRIM:
- TRACE("Request type is TRIM");
- ret = blk_co_discard(exp->blk, (request.from + exp->dev_offset)
- / BDRV_SECTOR_SIZE,
- request.len / BDRV_SECTOR_SIZE);
- if (ret < 0) {
- LOG("discard failed");
- reply.error = -ret;
- }
- if (nbd_co_send_reply(req, &reply, 0) < 0) {
- goto out;
- }
- break;
- default:
- LOG("invalid request type (%u) received", request.type);
- invalid_request:
- reply.error = EINVAL;
- error_reply:
- if (nbd_co_send_reply(req, &reply, 0) < 0) {
- goto out;
- }
- break;
- }
-
- TRACE("Request/Reply complete");
-
-done:
- nbd_request_put(req);
- return;
-
-out:
- nbd_request_put(req);
- client_close(client);
-}
-
-static void nbd_read(void *opaque)
-{
- NBDClient *client = opaque;
-
- if (client->recv_coroutine) {
- qemu_coroutine_enter(client->recv_coroutine, NULL);
- } else {
- qemu_coroutine_enter(qemu_coroutine_create(nbd_trip), client);
- }
-}
-
-static void nbd_restart_write(void *opaque)
-{
- NBDClient *client = opaque;
-
- qemu_coroutine_enter(client->send_coroutine, NULL);
-}
-
-static void nbd_set_handlers(NBDClient *client)
-{
- if (client->exp && client->exp->ctx) {
- aio_set_fd_handler(client->exp->ctx, client->sock,
- client->can_read ? nbd_read : NULL,
- client->send_coroutine ? nbd_restart_write : NULL,
- client);
- }
-}
-
-static void nbd_unset_handlers(NBDClient *client)
-{
- if (client->exp && client->exp->ctx) {
- aio_set_fd_handler(client->exp->ctx, client->sock, NULL, NULL, NULL);
- }
-}
-
-static void nbd_update_can_read(NBDClient *client)
-{
- bool can_read = client->recv_coroutine ||
- client->nb_requests < MAX_NBD_REQUESTS;
-
- if (can_read != client->can_read) {
- client->can_read = can_read;
- nbd_set_handlers(client);
-
- /* There is no need to invoke aio_notify(), since aio_set_fd_handler()
- * in nbd_set_handlers() will have taken care of that */
- }
-}
-
-NBDClient *nbd_client_new(NBDExport *exp, int csock,
- void (*close)(NBDClient *))
-{
- NBDClient *client;
- client = g_malloc0(sizeof(NBDClient));
- client->refcount = 1;
- client->exp = exp;
- client->sock = csock;
- client->can_read = true;
- if (nbd_send_negotiate(client)) {
- g_free(client);
- return NULL;
- }
- client->close = close;
- qemu_co_mutex_init(&client->send_lock);
- nbd_set_handlers(client);
-
- if (exp) {
- QTAILQ_INSERT_TAIL(&exp->clients, client, next);
- nbd_export_get(exp);
- }
- return client;
-}
Code Review / kvmfornfv.git / blobdiff