diff options
Diffstat (limited to 'nbd/client.c')
| -rw-r--r-- | nbd/client.c | 361 |
1 files changed, 361 insertions, 0 deletions
diff --git a/nbd/client.c b/nbd/client.c new file mode 100644 index 0000000000..83df7ba378 --- /dev/null +++ b/nbd/client.c @@ -0,0 +1,361 @@ +/* + * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> + * + * Network Block Device Client Side + * + * 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-internal.h" + +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 */ + +static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); + +/* That's all folks */ + +/* 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) + +*/ + +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_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_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; +} + +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; +} + |