diff options
Diffstat (limited to 'qemu/nbd/client.c')
| -rw-r--r-- | qemu/nbd/client.c | 745 |
1 files changed, 745 insertions, 0 deletions
diff --git a/qemu/nbd/client.c b/qemu/nbd/client.c new file mode 100644 index 000000000..48f2a21f3 --- /dev/null +++ b/qemu/nbd/client.c @@ -0,0 +1,745 @@ +/* + * 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 "qemu/osdep.h" +#include "qapi/error.h" +#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) + +*/ + + +/* If type represents success, return 1 without further action. + * If type represents an error reply, consume the rest of the packet on ioc. + * Then return 0 for unsupported (so the client can fall back to + * other approaches), or -1 with errp set for other errors. + */ +static int nbd_handle_reply_err(QIOChannel *ioc, uint32_t opt, uint32_t type, + Error **errp) +{ + uint32_t len; + char *msg = NULL; + int result = -1; + + if (!(type & (1 << 31))) { + return 1; + } + + if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) { + error_setg(errp, "failed to read option length"); + return -1; + } + len = be32_to_cpu(len); + if (len) { + if (len > NBD_MAX_BUFFER_SIZE) { + error_setg(errp, "server's error message is too long"); + goto cleanup; + } + msg = g_malloc(len + 1); + if (read_sync(ioc, msg, len) != len) { + error_setg(errp, "failed to read option error message"); + goto cleanup; + } + msg[len] = '\0'; + } + + switch (type) { + case NBD_REP_ERR_UNSUP: + TRACE("server doesn't understand request %d, attempting fallback", + opt); + result = 0; + goto cleanup; + + case NBD_REP_ERR_POLICY: + error_setg(errp, "Denied by server for option %x", opt); + break; + + case NBD_REP_ERR_INVALID: + error_setg(errp, "Invalid data length for option %x", opt); + break; + + case NBD_REP_ERR_TLS_REQD: + error_setg(errp, "TLS negotiation required before option %x", opt); + break; + + default: + error_setg(errp, "Unknown error code when asking for option %x", opt); + break; + } + + if (msg) { + error_append_hint(errp, "%s\n", msg); + } + + cleanup: + g_free(msg); + return result; +} + +static int nbd_receive_list(QIOChannel *ioc, char **name, Error **errp) +{ + uint64_t magic; + uint32_t opt; + uint32_t type; + uint32_t len; + uint32_t namelen; + int error; + + *name = NULL; + if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) { + error_setg(errp, "failed to read list option magic"); + return -1; + } + magic = be64_to_cpu(magic); + if (magic != NBD_REP_MAGIC) { + error_setg(errp, "Unexpected option list magic"); + return -1; + } + if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) { + error_setg(errp, "failed to read list option"); + return -1; + } + opt = be32_to_cpu(opt); + if (opt != NBD_OPT_LIST) { + error_setg(errp, "Unexpected option type %x expected %x", + opt, NBD_OPT_LIST); + return -1; + } + + if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) { + error_setg(errp, "failed to read list option type"); + return -1; + } + type = be32_to_cpu(type); + error = nbd_handle_reply_err(ioc, opt, type, errp); + if (error <= 0) { + return error; + } + + if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) { + error_setg(errp, "failed to read option length"); + return -1; + } + len = be32_to_cpu(len); + + if (type == NBD_REP_ACK) { + if (len != 0) { + error_setg(errp, "length too long for option end"); + return -1; + } + } else if (type == NBD_REP_SERVER) { + if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) { + error_setg(errp, "incorrect option length"); + return -1; + } + if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) { + error_setg(errp, "failed to read option name length"); + return -1; + } + namelen = be32_to_cpu(namelen); + len -= sizeof(namelen); + if (len < namelen) { + error_setg(errp, "incorrect option name length"); + return -1; + } + if (namelen > 255) { + error_setg(errp, "export name length too long %d", namelen); + return -1; + } + + *name = g_new0(char, namelen + 1); + if (read_sync(ioc, *name, namelen) != namelen) { + error_setg(errp, "failed to read export name"); + g_free(*name); + *name = NULL; + return -1; + } + (*name)[namelen] = '\0'; + len -= namelen; + if (len) { + char *buf = g_malloc(len + 1); + if (read_sync(ioc, buf, len) != len) { + error_setg(errp, "failed to read export description"); + g_free(*name); + g_free(buf); + *name = NULL; + return -1; + } + buf[len] = '\0'; + TRACE("Ignoring export description: %s", buf); + g_free(buf); + } + } else { + error_setg(errp, "Unexpected reply type %x expected %x", + type, NBD_REP_SERVER); + return -1; + } + return 1; +} + + +static int nbd_receive_query_exports(QIOChannel *ioc, + const char *wantname, + Error **errp) +{ + uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC); + uint32_t opt = cpu_to_be32(NBD_OPT_LIST); + uint32_t length = 0; + bool foundExport = false; + + TRACE("Querying export list"); + if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) { + error_setg(errp, "Failed to send list option magic"); + return -1; + } + + if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) { + error_setg(errp, "Failed to send list option number"); + return -1; + } + + if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) { + error_setg(errp, "Failed to send list option length"); + return -1; + } + + TRACE("Reading available export names"); + while (1) { + char *name = NULL; + int ret = nbd_receive_list(ioc, &name, errp); + + if (ret < 0) { + g_free(name); + name = NULL; + return -1; + } + if (ret == 0) { + /* Server doesn't support export listing, so + * we will just assume an export with our + * wanted name exists */ + foundExport = true; + break; + } + if (name == NULL) { + TRACE("End of export name list"); + break; + } + if (g_str_equal(name, wantname)) { + foundExport = true; + TRACE("Found desired export name '%s'", name); + } else { + TRACE("Ignored export name '%s'", name); + } + g_free(name); + } + + if (!foundExport) { + error_setg(errp, "No export with name '%s' available", wantname); + return -1; + } + + return 0; +} + +static QIOChannel *nbd_receive_starttls(QIOChannel *ioc, + QCryptoTLSCreds *tlscreds, + const char *hostname, Error **errp) +{ + uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC); + uint32_t opt = cpu_to_be32(NBD_OPT_STARTTLS); + uint32_t length = 0; + uint32_t type; + QIOChannelTLS *tioc; + struct NBDTLSHandshakeData data = { 0 }; + + TRACE("Requesting TLS from server"); + if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) { + error_setg(errp, "Failed to send option magic"); + return NULL; + } + + if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) { + error_setg(errp, "Failed to send option number"); + return NULL; + } + + if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) { + error_setg(errp, "Failed to send option length"); + return NULL; + } + + TRACE("Getting TLS reply from server1"); + if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) { + error_setg(errp, "failed to read option magic"); + return NULL; + } + magic = be64_to_cpu(magic); + if (magic != NBD_REP_MAGIC) { + error_setg(errp, "Unexpected option magic"); + return NULL; + } + TRACE("Getting TLS reply from server2"); + if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) { + error_setg(errp, "failed to read option"); + return NULL; + } + opt = be32_to_cpu(opt); + if (opt != NBD_OPT_STARTTLS) { + error_setg(errp, "Unexpected option type %x expected %x", + opt, NBD_OPT_STARTTLS); + return NULL; + } + + TRACE("Getting TLS reply from server"); + if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) { + error_setg(errp, "failed to read option type"); + return NULL; + } + type = be32_to_cpu(type); + if (type != NBD_REP_ACK) { + error_setg(errp, "Server rejected request to start TLS %x", + type); + return NULL; + } + + TRACE("Getting TLS reply from server"); + if (read_sync(ioc, &length, sizeof(length)) != sizeof(length)) { + error_setg(errp, "failed to read option length"); + return NULL; + } + length = be32_to_cpu(length); + if (length != 0) { + error_setg(errp, "Start TLS reponse was not zero %x", + length); + return NULL; + } + + TRACE("TLS request approved, setting up TLS"); + tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp); + if (!tioc) { + return NULL; + } + data.loop = g_main_loop_new(g_main_context_default(), FALSE); + TRACE("Starting TLS hanshake"); + qio_channel_tls_handshake(tioc, + nbd_tls_handshake, + &data, + NULL); + + if (!data.complete) { + g_main_loop_run(data.loop); + } + g_main_loop_unref(data.loop); + if (data.error) { + error_propagate(errp, data.error); + object_unref(OBJECT(tioc)); + return NULL; + } + + return QIO_CHANNEL(tioc); +} + + +int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags, + QCryptoTLSCreds *tlscreds, const char *hostname, + QIOChannel **outioc, + off_t *size, Error **errp) +{ + char buf[256]; + uint64_t magic, s; + int rc; + + TRACE("Receiving negotiation tlscreds=%p hostname=%s.", + tlscreds, hostname ? hostname : "<null>"); + + rc = -EINVAL; + + if (outioc) { + *outioc = NULL; + } + if (tlscreds && !outioc) { + error_setg(errp, "Output I/O channel required for TLS"); + goto fail; + } + + if (read_sync(ioc, 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(ioc, &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 (magic == NBD_OPTS_MAGIC) { + uint32_t clientflags = 0; + uint32_t opt; + uint32_t namesize; + uint16_t globalflags; + uint16_t exportflags; + bool fixedNewStyle = false; + + if (read_sync(ioc, &globalflags, sizeof(globalflags)) != + sizeof(globalflags)) { + error_setg(errp, "Failed to read server flags"); + goto fail; + } + globalflags = be16_to_cpu(globalflags); + *flags = globalflags << 16; + TRACE("Global flags are %x", globalflags); + if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) { + fixedNewStyle = true; + TRACE("Server supports fixed new style"); + clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE; + } + /* client requested flags */ + clientflags = cpu_to_be32(clientflags); + if (write_sync(ioc, &clientflags, sizeof(clientflags)) != + sizeof(clientflags)) { + error_setg(errp, "Failed to send clientflags field"); + goto fail; + } + if (tlscreds) { + if (fixedNewStyle) { + *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp); + if (!*outioc) { + goto fail; + } + ioc = *outioc; + } else { + error_setg(errp, "Server does not support STARTTLS"); + goto fail; + } + } + if (!name) { + TRACE("Using default NBD export name \"\""); + name = ""; + } + if (fixedNewStyle) { + /* Check our desired export is present in the + * server export list. Since NBD_OPT_EXPORT_NAME + * cannot return an error message, running this + * query gives us good error reporting if the + * server required TLS + */ + if (nbd_receive_query_exports(ioc, name, errp) < 0) { + goto fail; + } + } + /* write the export name */ + magic = cpu_to_be64(magic); + if (write_sync(ioc, &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(ioc, &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(ioc, &namesize, sizeof(namesize)) != + sizeof(namesize)) { + error_setg(errp, "Failed to send export name length"); + goto fail; + } + if (write_sync(ioc, (char *)name, strlen(name)) != strlen(name)) { + error_setg(errp, "Failed to send export name"); + goto fail; + } + + if (read_sync(ioc, &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 (read_sync(ioc, &exportflags, sizeof(exportflags)) != + sizeof(exportflags)) { + error_setg(errp, "Failed to read export flags"); + goto fail; + } + exportflags = be16_to_cpu(exportflags); + *flags |= exportflags; + TRACE("Export flags are %x", exportflags); + } else if (magic == NBD_CLIENT_MAGIC) { + if (name) { + error_setg(errp, "Server does not support export names"); + goto fail; + } + if (tlscreds) { + error_setg(errp, "Server does not support STARTTLS"); + goto fail; + } + + if (read_sync(ioc, &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 (read_sync(ioc, flags, sizeof(*flags)) != sizeof(*flags)) { + error_setg(errp, "Failed to read export flags"); + goto fail; + } + *flags = be32_to_cpup(flags); + } else { + error_setg(errp, "Bad magic received"); + goto fail; + } + + if (read_sync(ioc, &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, QIOChannelSocket *sioc, uint32_t flags, off_t size) +{ + TRACE("Setting NBD socket"); + + if (ioctl(fd, NBD_SET_SOCK, sioc->fd) < 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, QIOChannelSocket *ioc, uint32_t flags, off_t size) +{ + return -ENOTSUP; +} + +int nbd_client(int fd) +{ + return -ENOTSUP; +} +#endif + +ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request) +{ + uint8_t buf[NBD_REQUEST_SIZE]; + ssize_t ret; + + TRACE("Sending request to server: " + "{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}", + request->from, request->len, request->handle, request->type); + + 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); + + ret = write_sync(ioc, 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(QIOChannel *ioc, struct nbd_reply *reply) +{ + uint8_t buf[NBD_REPLY_SIZE]; + uint32_t magic; + ssize_t ret; + + ret = read_sync(ioc, 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; +} + |