diff options
Diffstat (limited to 'nbd/client.c')
-rw-r--r-- | nbd/client.c | 498 |
1 files changed, 269 insertions, 229 deletions
diff --git a/nbd/client.c b/nbd/client.c index f6db8369b3..7db4301d29 100644 --- a/nbd/client.c +++ b/nbd/client.c @@ -1,4 +1,5 @@ /* + * Copyright (C) 2016 Red Hat, Inc. * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> * * Network Block Device Client Side @@ -22,23 +23,34 @@ static int nbd_errno_to_system_errno(int err) { + int ret; switch (err) { case NBD_SUCCESS: - return 0; + ret = 0; + break; case NBD_EPERM: - return EPERM; + ret = EPERM; + break; case NBD_EIO: - return EIO; + ret = EIO; + break; case NBD_ENOMEM: - return ENOMEM; + ret = ENOMEM; + break; case NBD_ENOSPC: - return ENOSPC; + ret = ENOSPC; + break; + case NBD_ESHUTDOWN: + ret = ESHUTDOWN; + break; default: TRACE("Squashing unexpected error %d to EINVAL", err); /* fallthrough */ case NBD_EINVAL: - return EINVAL; + ret = EINVAL; + break; } + return ret; } /* Definitions for opaque data types */ @@ -74,64 +86,180 @@ static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); */ +/* Discard length bytes from channel. Return -errno on failure, or + * the amount of bytes consumed. */ +static ssize_t drop_sync(QIOChannel *ioc, size_t size) +{ + ssize_t ret, dropped = size; + char small[1024]; + char *buffer; + + buffer = sizeof(small) < size ? small : g_malloc(MIN(65536, size)); + while (size > 0) { + ret = read_sync(ioc, buffer, MIN(65536, size)); + if (ret < 0) { + goto cleanup; + } + assert(ret <= size); + size -= ret; + } + ret = dropped; + + cleanup: + if (buffer != small) { + g_free(buffer); + } + return ret; +} + +/* Send an option request. + * + * The request is for option @opt, with @data containing @len bytes of + * additional payload for the request (@len may be -1 to treat @data as + * a C string; and @data may be NULL if @len is 0). + * Return 0 if successful, -1 with errp set if it is impossible to + * continue. */ +static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt, + uint32_t len, const char *data, + Error **errp) +{ + nbd_option req; + QEMU_BUILD_BUG_ON(sizeof(req) != 16); + + if (len == -1) { + req.length = len = strlen(data); + } + TRACE("Sending option request %" PRIu32", len %" PRIu32, opt, len); -/* 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. + stq_be_p(&req.magic, NBD_OPTS_MAGIC); + stl_be_p(&req.option, opt); + stl_be_p(&req.length, len); + + if (write_sync(ioc, &req, sizeof(req)) != sizeof(req)) { + error_setg(errp, "Failed to send option request header"); + return -1; + } + + if (len && write_sync(ioc, (char *) data, len) != len) { + error_setg(errp, "Failed to send option request data"); + return -1; + } + + return 0; +} + +/* Send NBD_OPT_ABORT as a courtesy to let the server know that we are + * not going to attempt further negotiation. */ +static void nbd_send_opt_abort(QIOChannel *ioc) +{ + /* Technically, a compliant server is supposed to reply to us; but + * older servers disconnected instead. At any rate, we're allowed + * to disconnect without waiting for the server reply, so we don't + * even care if the request makes it to the server, let alone + * waiting around for whether the server replies. */ + nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL); +} + + +/* Receive the header of an option reply, which should match the given + * opt. Read through the length field, but NOT the length bytes of + * payload. Return 0 if successful, -1 with errp set if it is + * impossible to continue. */ +static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt, + nbd_opt_reply *reply, Error **errp) +{ + QEMU_BUILD_BUG_ON(sizeof(*reply) != 20); + if (read_sync(ioc, reply, sizeof(*reply)) != sizeof(*reply)) { + error_setg(errp, "failed to read option reply"); + nbd_send_opt_abort(ioc); + return -1; + } + be64_to_cpus(&reply->magic); + be32_to_cpus(&reply->option); + be32_to_cpus(&reply->type); + be32_to_cpus(&reply->length); + + TRACE("Received option reply %" PRIx32", type %" PRIx32", len %" PRIu32, + reply->option, reply->type, reply->length); + + if (reply->magic != NBD_REP_MAGIC) { + error_setg(errp, "Unexpected option reply magic"); + nbd_send_opt_abort(ioc); + return -1; + } + if (reply->option != opt) { + error_setg(errp, "Unexpected option type %x expected %x", + reply->option, opt); + nbd_send_opt_abort(ioc); + return -1; + } + return 0; +} + +/* If reply represents success, return 1 without further action. + * If reply represents an error, consume the optional payload 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, +static int nbd_handle_reply_err(QIOChannel *ioc, nbd_opt_reply *reply, Error **errp) { - uint32_t len; char *msg = NULL; int result = -1; - if (!(type & (1 << 31))) { + if (!(reply->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) { + if (reply->length) { + if (reply->length > 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) { + msg = g_malloc(reply->length + 1); + if (read_sync(ioc, msg, reply->length) != reply->length) { error_setg(errp, "failed to read option error message"); goto cleanup; } - msg[len] = '\0'; + msg[reply->length] = '\0'; } - switch (type) { + switch (reply->type) { case NBD_REP_ERR_UNSUP: TRACE("server doesn't understand request %" PRIx32 - ", attempting fallback", opt); + ", attempting fallback", reply->option); result = 0; goto cleanup; case NBD_REP_ERR_POLICY: - error_setg(errp, "Denied by server for option %" PRIx32, opt); + error_setg(errp, "Denied by server for option %" PRIx32, + reply->option); break; case NBD_REP_ERR_INVALID: - error_setg(errp, "Invalid data length for option %" PRIx32, opt); + error_setg(errp, "Invalid data length for option %" PRIx32, + reply->option); + break; + + case NBD_REP_ERR_PLATFORM: + error_setg(errp, "Server lacks support for option %" PRIx32, + reply->option); break; case NBD_REP_ERR_TLS_REQD: error_setg(errp, "TLS negotiation required before option %" PRIx32, - opt); + reply->option); + break; + + case NBD_REP_ERR_SHUTDOWN: + error_setg(errp, "Server shutting down before option %" PRIx32, + reply->option); break; default: error_setg(errp, "Unknown error code when asking for option %" PRIx32, - opt); + reply->option); break; } @@ -141,244 +269,160 @@ static int nbd_handle_reply_err(QIOChannel *ioc, uint32_t opt, uint32_t type, cleanup: g_free(msg); + if (result < 0) { + nbd_send_opt_abort(ioc); + } return result; } -static int nbd_receive_list(QIOChannel *ioc, char **name, Error **errp) +/* Process another portion of the NBD_OPT_LIST reply. Set *@match if + * the current reply matches @want or if the server does not support + * NBD_OPT_LIST, otherwise leave @match alone. Return 0 if iteration + * is complete, positive if more replies are expected, or negative + * with @errp set if an unrecoverable error occurred. */ +static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match, + Error **errp) { - uint64_t magic; - uint32_t opt; - uint32_t type; + nbd_opt_reply reply; uint32_t len; uint32_t namelen; + char name[NBD_MAX_NAME_SIZE + 1]; int error; - *name = NULL; - if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) { - error_setg(errp, "failed to read list option magic"); + if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) { 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; + error = nbd_handle_reply_err(ioc, &reply, errp); + if (error <= 0) { + /* The server did not support NBD_OPT_LIST, so set *match on + * the assumption that any name will be accepted. */ + *match = true; + return error; } - opt = be32_to_cpu(opt); - if (opt != NBD_OPT_LIST) { - error_setg(errp, "Unexpected option type %" PRIx32 " expected %x", - opt, NBD_OPT_LIST); + len = reply.length; + + if (reply.type == NBD_REP_ACK) { + if (len != 0) { + error_setg(errp, "length too long for option end"); + nbd_send_opt_abort(ioc); + return -1; + } + return 0; + } else if (reply.type != NBD_REP_SERVER) { + error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x", + reply.type, NBD_REP_SERVER); + nbd_send_opt_abort(ioc); return -1; } - if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) { - error_setg(errp, "failed to read list option type"); + if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) { + error_setg(errp, "incorrect option length %" PRIu32, len); + nbd_send_opt_abort(ioc); 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, &namelen, sizeof(namelen)) != sizeof(namelen)) { + error_setg(errp, "failed to read option name length"); + nbd_send_opt_abort(ioc); + return -1; } - - if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) { - error_setg(errp, "failed to read option length"); + namelen = be32_to_cpu(namelen); + len -= sizeof(namelen); + if (len < namelen) { + error_setg(errp, "incorrect option name length"); + nbd_send_opt_abort(ioc); 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 > NBD_MAX_NAME_SIZE) { - error_setg(errp, "export name length too long %" PRIu32, namelen); + if (namelen != strlen(want)) { + if (drop_sync(ioc, len) != len) { + error_setg(errp, "failed to skip export name with wrong length"); + nbd_send_opt_abort(ioc); return -1; } + 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 %" PRIx32 " expected %x", - type, NBD_REP_SERVER); + assert(namelen < sizeof(name)); + if (read_sync(ioc, name, namelen) != namelen) { + error_setg(errp, "failed to read export name"); + nbd_send_opt_abort(ioc); return -1; } + name[namelen] = '\0'; + len -= namelen; + if (drop_sync(ioc, len) != len) { + error_setg(errp, "failed to read export description"); + nbd_send_opt_abort(ioc); + return -1; + } + if (!strcmp(name, want)) { + *match = true; + } return 1; } +/* Return -1 on failure, 0 if wantname is an available export. */ 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"); + TRACE("Querying export list for '%s'", wantname); + if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) { return -1; } TRACE("Reading available export names"); while (1) { - char *name = NULL; - int ret = nbd_receive_list(ioc, &name, errp); + int ret = nbd_receive_list(ioc, wantname, &foundExport, errp); if (ret < 0) { - g_free(name); - name = NULL; + /* Server gave unexpected reply */ return -1; + } else if (ret == 0) { + /* Done iterating. */ + if (!foundExport) { + error_setg(errp, "No export with name '%s' available", + wantname); + nbd_send_opt_abort(ioc); + return -1; + } + TRACE("Found desired export name '%s'", wantname); + return 0; } - 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; + nbd_opt_reply reply; 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 %" PRIx32 " expected %x", - opt, NBD_OPT_STARTTLS); + if (nbd_send_option_request(ioc, NBD_OPT_STARTTLS, 0, NULL, errp) < 0) { 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"); + if (nbd_receive_option_reply(ioc, NBD_OPT_STARTTLS, &reply, errp) < 0) { return NULL; } - type = be32_to_cpu(type); - if (type != NBD_REP_ACK) { + + if (reply.type != NBD_REP_ACK) { error_setg(errp, "Server rejected request to start TLS %" PRIx32, - type); + reply.type); + nbd_send_opt_abort(ioc); 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) { + if (reply.length != 0) { error_setg(errp, "Start TLS response was not zero %" PRIu32, - length); + reply.length); + nbd_send_opt_abort(ioc); return NULL; } @@ -417,6 +461,7 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags, char buf[256]; uint64_t magic, s; int rc; + bool zeroes = true; TRACE("Receiving negotiation tlscreds=%p hostname=%s.", tlscreds, hostname ? hostname : "<null>"); @@ -466,8 +511,6 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags, if (magic == NBD_OPTS_MAGIC) { uint32_t clientflags = 0; - uint32_t opt; - uint32_t namesize; uint16_t globalflags; bool fixedNewStyle = false; @@ -483,6 +526,11 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags, TRACE("Server supports fixed new style"); clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE; } + if (globalflags & NBD_FLAG_NO_ZEROES) { + zeroes = false; + TRACE("Server supports no zeroes"); + clientflags |= NBD_FLAG_C_NO_ZEROES; + } /* client requested flags */ clientflags = cpu_to_be32(clientflags); if (write_sync(ioc, &clientflags, sizeof(clientflags)) != @@ -517,28 +565,13 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags, 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"); + /* write the export name request */ + if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, name, + errp) < 0) { goto fail; } + /* Read the response */ if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) { error_setg(errp, "Failed to read export length"); goto fail; @@ -585,7 +618,7 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags, } TRACE("Size is %" PRIu64 ", export flags %" PRIx16, *size, *flags); - if (read_sync(ioc, &buf, 124) != 124) { + if (zeroes && drop_sync(ioc, 124) != 124) { error_setg(errp, "Failed to read reserved block"); goto fail; } @@ -707,18 +740,20 @@ int nbd_disconnect(int fd) } #endif -ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request) +ssize_t nbd_send_request(QIOChannel *ioc, NBDRequest *request) { uint8_t buf[NBD_REQUEST_SIZE]; ssize_t ret; TRACE("Sending request to server: " "{ .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64 - ", .type=%" PRIu32 " }", - request->from, request->len, request->handle, request->type); + ", .flags = %" PRIx16 ", .type = %" PRIu16 " }", + request->from, request->len, request->handle, + request->flags, request->type); stl_be_p(buf, NBD_REQUEST_MAGIC); - stl_be_p(buf + 4, request->type); + stw_be_p(buf + 4, request->flags); + stw_be_p(buf + 6, request->type); stq_be_p(buf + 8, request->handle); stq_be_p(buf + 16, request->from); stl_be_p(buf + 24, request->len); @@ -735,7 +770,7 @@ ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request) return 0; } -ssize_t nbd_receive_reply(QIOChannel *ioc, struct nbd_reply *reply) +ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply *reply) { uint8_t buf[NBD_REPLY_SIZE]; uint32_t magic; @@ -763,6 +798,11 @@ ssize_t nbd_receive_reply(QIOChannel *ioc, struct nbd_reply *reply) reply->error = nbd_errno_to_system_errno(reply->error); + if (reply->error == ESHUTDOWN) { + /* This works even on mingw which lacks a native ESHUTDOWN */ + LOG("server shutting down"); + return -EINVAL; + } TRACE("Got reply: { magic = 0x%" PRIx32 ", .error = % " PRId32 ", handle = %" PRIu64" }", magic, reply->error, reply->handle); 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