mirror of https://github.com/proxmox/mirror_qemu
362 lines
9.4 KiB
C
362 lines
9.4 KiB
C
/*
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* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
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*
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* Network Block Device Client Side
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; under version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "nbd-internal.h"
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static int nbd_errno_to_system_errno(int err)
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{
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switch (err) {
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case NBD_SUCCESS:
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return 0;
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case NBD_EPERM:
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return EPERM;
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case NBD_EIO:
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return EIO;
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case NBD_ENOMEM:
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return ENOMEM;
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case NBD_ENOSPC:
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return ENOSPC;
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case NBD_EINVAL:
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default:
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return EINVAL;
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}
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}
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/* Definitions for opaque data types */
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static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
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/* That's all folks */
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/* Basic flow for negotiation
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Server Client
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Negotiate
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or
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Server Client
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Negotiate #1
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Option
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Negotiate #2
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----
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followed by
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Server Client
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Request
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Response
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Request
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Response
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...
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...
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Request (type == 2)
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*/
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int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
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off_t *size, Error **errp)
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{
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char buf[256];
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uint64_t magic, s;
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uint16_t tmp;
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int rc;
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TRACE("Receiving negotiation.");
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rc = -EINVAL;
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if (read_sync(csock, buf, 8) != 8) {
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error_setg(errp, "Failed to read data");
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goto fail;
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}
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buf[8] = '\0';
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if (strlen(buf) == 0) {
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error_setg(errp, "Server connection closed unexpectedly");
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goto fail;
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}
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TRACE("Magic is %c%c%c%c%c%c%c%c",
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qemu_isprint(buf[0]) ? buf[0] : '.',
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qemu_isprint(buf[1]) ? buf[1] : '.',
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qemu_isprint(buf[2]) ? buf[2] : '.',
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qemu_isprint(buf[3]) ? buf[3] : '.',
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qemu_isprint(buf[4]) ? buf[4] : '.',
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qemu_isprint(buf[5]) ? buf[5] : '.',
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qemu_isprint(buf[6]) ? buf[6] : '.',
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qemu_isprint(buf[7]) ? buf[7] : '.');
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if (memcmp(buf, "NBDMAGIC", 8) != 0) {
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error_setg(errp, "Invalid magic received");
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goto fail;
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}
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if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
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error_setg(errp, "Failed to read magic");
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goto fail;
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}
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magic = be64_to_cpu(magic);
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TRACE("Magic is 0x%" PRIx64, magic);
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if (name) {
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uint32_t reserved = 0;
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uint32_t opt;
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uint32_t namesize;
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TRACE("Checking magic (opts_magic)");
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if (magic != NBD_OPTS_MAGIC) {
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if (magic == NBD_CLIENT_MAGIC) {
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error_setg(errp, "Server does not support export names");
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} else {
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error_setg(errp, "Bad magic received");
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}
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goto fail;
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}
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if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
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error_setg(errp, "Failed to read server flags");
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goto fail;
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}
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*flags = be16_to_cpu(tmp) << 16;
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/* reserved for future use */
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if (write_sync(csock, &reserved, sizeof(reserved)) !=
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sizeof(reserved)) {
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error_setg(errp, "Failed to read reserved field");
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goto fail;
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}
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/* write the export name */
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magic = cpu_to_be64(magic);
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if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
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error_setg(errp, "Failed to send export name magic");
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goto fail;
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}
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opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
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if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
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error_setg(errp, "Failed to send export name option number");
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goto fail;
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}
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namesize = cpu_to_be32(strlen(name));
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if (write_sync(csock, &namesize, sizeof(namesize)) !=
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sizeof(namesize)) {
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error_setg(errp, "Failed to send export name length");
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goto fail;
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}
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if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) {
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error_setg(errp, "Failed to send export name");
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goto fail;
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}
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} else {
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TRACE("Checking magic (cli_magic)");
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if (magic != NBD_CLIENT_MAGIC) {
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if (magic == NBD_OPTS_MAGIC) {
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error_setg(errp, "Server requires an export name");
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} else {
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error_setg(errp, "Bad magic received");
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}
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goto fail;
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}
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}
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if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) {
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error_setg(errp, "Failed to read export length");
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goto fail;
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}
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*size = be64_to_cpu(s);
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TRACE("Size is %" PRIu64, *size);
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if (!name) {
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if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) {
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error_setg(errp, "Failed to read export flags");
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goto fail;
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}
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*flags = be32_to_cpup(flags);
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} else {
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if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
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error_setg(errp, "Failed to read export flags");
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goto fail;
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}
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*flags |= be16_to_cpu(tmp);
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}
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if (read_sync(csock, &buf, 124) != 124) {
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error_setg(errp, "Failed to read reserved block");
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goto fail;
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}
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rc = 0;
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fail:
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return rc;
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}
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#ifdef __linux__
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int nbd_init(int fd, int csock, uint32_t flags, off_t size)
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{
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TRACE("Setting NBD socket");
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if (ioctl(fd, NBD_SET_SOCK, csock) < 0) {
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int serrno = errno;
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LOG("Failed to set NBD socket");
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return -serrno;
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}
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TRACE("Setting block size to %lu", (unsigned long)BDRV_SECTOR_SIZE);
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if (ioctl(fd, NBD_SET_BLKSIZE, (size_t)BDRV_SECTOR_SIZE) < 0) {
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int serrno = errno;
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LOG("Failed setting NBD block size");
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return -serrno;
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}
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TRACE("Setting size to %zd block(s)", (size_t)(size / BDRV_SECTOR_SIZE));
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if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE)) < 0) {
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int serrno = errno;
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LOG("Failed setting size (in blocks)");
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return -serrno;
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}
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if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) {
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if (errno == ENOTTY) {
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int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
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TRACE("Setting readonly attribute");
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if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
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int serrno = errno;
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LOG("Failed setting read-only attribute");
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return -serrno;
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}
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} else {
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int serrno = errno;
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LOG("Failed setting flags");
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return -serrno;
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}
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}
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TRACE("Negotiation ended");
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return 0;
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}
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int nbd_client(int fd)
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{
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int ret;
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int serrno;
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TRACE("Doing NBD loop");
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ret = ioctl(fd, NBD_DO_IT);
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if (ret < 0 && errno == EPIPE) {
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/* NBD_DO_IT normally returns EPIPE when someone has disconnected
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* the socket via NBD_DISCONNECT. We do not want to return 1 in
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* that case.
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*/
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ret = 0;
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}
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serrno = errno;
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TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
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TRACE("Clearing NBD queue");
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ioctl(fd, NBD_CLEAR_QUE);
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TRACE("Clearing NBD socket");
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ioctl(fd, NBD_CLEAR_SOCK);
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errno = serrno;
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return ret;
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}
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#else
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int nbd_init(int fd, int csock, uint32_t flags, off_t size)
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{
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return -ENOTSUP;
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}
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int nbd_client(int fd)
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{
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return -ENOTSUP;
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}
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#endif
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ssize_t nbd_send_request(int csock, struct nbd_request *request)
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{
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uint8_t buf[NBD_REQUEST_SIZE];
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ssize_t ret;
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cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
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cpu_to_be32w((uint32_t*)(buf + 4), request->type);
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cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
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cpu_to_be64w((uint64_t*)(buf + 16), request->from);
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cpu_to_be32w((uint32_t*)(buf + 24), request->len);
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TRACE("Sending request to client: "
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"{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
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request->from, request->len, request->handle, request->type);
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ret = write_sync(csock, buf, sizeof(buf));
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if (ret < 0) {
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return ret;
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}
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if (ret != sizeof(buf)) {
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LOG("writing to socket failed");
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return -EINVAL;
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}
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return 0;
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}
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ssize_t nbd_receive_reply(int csock, struct nbd_reply *reply)
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{
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uint8_t buf[NBD_REPLY_SIZE];
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uint32_t magic;
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ssize_t ret;
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ret = read_sync(csock, buf, sizeof(buf));
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if (ret < 0) {
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return ret;
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}
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if (ret != sizeof(buf)) {
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LOG("read failed");
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return -EINVAL;
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}
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/* Reply
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[ 0 .. 3] magic (NBD_REPLY_MAGIC)
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[ 4 .. 7] error (0 == no error)
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[ 7 .. 15] handle
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*/
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magic = be32_to_cpup((uint32_t*)buf);
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reply->error = be32_to_cpup((uint32_t*)(buf + 4));
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reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
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reply->error = nbd_errno_to_system_errno(reply->error);
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TRACE("Got reply: "
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"{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
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magic, reply->error, reply->handle);
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if (magic != NBD_REPLY_MAGIC) {
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LOG("invalid magic (got 0x%x)", magic);
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return -EINVAL;
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}
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return 0;
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}
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