/* * 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 "nbd.h" #include "block.h" #include "qemu-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_socket.h" #include "qemu-queue.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 */ #define NBD_REPLY_SIZE (4 + 4 + 8) #define NBD_REQUEST_MAGIC 0x25609513 #define NBD_REPLY_MAGIC 0x67446698 #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 << 0) /* That's all folks */ 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)) { 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 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; } static void combine_addr(char *buf, size_t len, const char* address, uint16_t port) { /* If the address-part contains a colon, it's an IPv6 IP so needs [] */ if (strstr(address, ":")) { snprintf(buf, len, "[%s]:%u", address, port); } else { snprintf(buf, len, "%s:%u", address, port); } } int tcp_socket_outgoing(const char *address, uint16_t port) { char address_and_port[128]; combine_addr(address_and_port, 128, address, port); return tcp_socket_outgoing_spec(address_and_port); } int tcp_socket_outgoing_spec(const char *address_and_port) { return inet_connect(address_and_port, true, NULL, NULL); } int tcp_socket_incoming(const char *address, uint16_t port) { char address_and_port[128]; combine_addr(address_and_port, 128, address, port); return tcp_socket_incoming_spec(address_and_port); } int tcp_socket_incoming_spec(const char *address_and_port) { char *ostr = NULL; int olen = 0; return inet_listen(address_and_port, ostr, olen, SOCK_STREAM, 0, NULL); } int unix_socket_incoming(const char *path) { char *ostr = NULL; int olen = 0; return unix_listen(path, ostr, olen); } int unix_socket_outgoing(const char *path) { return unix_connect(path); } /* Basic flow Server Client Negotiate Request Response Request Response ... ... Request (type == 2) */ static int nbd_send_negotiate(int csock, off_t size, uint32_t flags) { char buf[8 + 8 + 8 + 128]; int rc; /* Negotiate [ 0 .. 7] passwd ("NBDMAGIC") [ 8 .. 15] magic (0x00420281861253) [16 .. 23] size [24 .. 27] flags [28 .. 151] reserved (0) */ socket_set_block(csock); rc = -EINVAL; TRACE("Beginning negotiation."); memcpy(buf, "NBDMAGIC", 8); cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL); cpu_to_be64w((uint64_t*)(buf + 16), size); cpu_to_be32w((uint32_t*)(buf + 24), flags | NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA); memset(buf + 28, 0, 124); if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { LOG("write failed"); goto fail; } TRACE("Negotiation succeeded."); rc = 0; fail: socket_set_nonblock(csock); return rc; } int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags, off_t *size, size_t *blocksize) { char buf[256]; uint64_t magic, s; uint16_t tmp; int rc; TRACE("Receiving negotiation."); socket_set_block(csock); rc = -EINVAL; if (read_sync(csock, buf, 8) != 8) { LOG("read failed"); goto fail; } buf[8] = '\0'; if (strlen(buf) == 0) { LOG("server connection closed"); 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) { LOG("Invalid magic received"); goto fail; } if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { LOG("read failed"); 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 != 0x49484156454F5054LL) { LOG("Bad magic received"); goto fail; } if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { LOG("flags read failed"); goto fail; } *flags = be16_to_cpu(tmp) << 16; /* reserved for future use */ if (write_sync(csock, &reserved, sizeof(reserved)) != sizeof(reserved)) { LOG("write failed (reserved)"); goto fail; } /* write the export name */ magic = cpu_to_be64(magic); if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { LOG("write failed (magic)"); goto fail; } opt = cpu_to_be32(NBD_OPT_EXPORT_NAME); if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) { LOG("write failed (opt)"); goto fail; } namesize = cpu_to_be32(strlen(name)); if (write_sync(csock, &namesize, sizeof(namesize)) != sizeof(namesize)) { LOG("write failed (namesize)"); goto fail; } if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) { LOG("write failed (name)"); goto fail; } } else { TRACE("Checking magic (cli_magic)"); if (magic != 0x00420281861253LL) { LOG("Bad magic received"); goto fail; } } if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) { LOG("read failed"); goto fail; } *size = be64_to_cpu(s); *blocksize = 1024; TRACE("Size is %" PRIu64, *size); if (!name) { if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) { LOG("read failed (flags)"); goto fail; } *flags = be32_to_cpup(flags); } else { if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { LOG("read failed (tmp)"); goto fail; } *flags |= be32_to_cpu(tmp); } if (read_sync(csock, &buf, 124) != 124) { LOG("read failed (buf)"); goto fail; } rc = 0; fail: socket_set_nonblock(csock); return rc; } #ifdef __linux__ int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize) { 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)blocksize); if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) < 0) { int serrno = errno; LOG("Failed setting NBD block size"); return -serrno; } TRACE("Setting size to %zd block(s)", (size_t)(size / blocksize)); if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) < 0) { int serrno = errno; LOG("Failed setting size (in blocks)"); return -serrno; } if (flags & NBD_FLAG_READ_ONLY) { int read_only = 1; TRACE("Setting readonly attribute"); if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) { int serrno = errno; LOG("Failed setting read-only attribute"); return -serrno; } } if (ioctl(fd, NBD_SET_FLAGS, flags) < 0 && errno != ENOTTY) { 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, size_t blocksize) { 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[4 + 4 + 8 + 8 + 4]; 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[4 + 4 + 8 + 8 + 4]; 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)); 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[4 + 4 + 8]; ssize_t ret; /* 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 typedef struct NBDRequest NBDRequest; struct NBDRequest { QSIMPLEQ_ENTRY(NBDRequest) entry; NBDClient *client; uint8_t *data; }; struct NBDExport { BlockDriverState *bs; off_t dev_offset; off_t size; uint32_t nbdflags; QSIMPLEQ_HEAD(, NBDRequest) requests; }; struct NBDClient { int refcount; void (*close)(NBDClient *client); NBDExport *exp; int sock; Coroutine *recv_coroutine; CoMutex send_lock; Coroutine *send_coroutine; int nb_requests; }; static void nbd_client_get(NBDClient *client) { client->refcount++; } static void nbd_client_put(NBDClient *client) { if (--client->refcount == 0) { g_free(client); } } static void nbd_client_close(NBDClient *client) { qemu_set_fd_handler2(client->sock, NULL, NULL, NULL, NULL); close(client->sock); client->sock = -1; if (client->close) { client->close(client); } nbd_client_put(client); } static NBDRequest *nbd_request_get(NBDClient *client) { NBDRequest *req; NBDExport *exp = client->exp; assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); client->nb_requests++; if (QSIMPLEQ_EMPTY(&exp->requests)) { req = g_malloc0(sizeof(NBDRequest)); req->data = qemu_blockalign(exp->bs, NBD_BUFFER_SIZE); } else { req = QSIMPLEQ_FIRST(&exp->requests); QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry); } nbd_client_get(client); req->client = client; return req; } static void nbd_request_put(NBDRequest *req) { NBDClient *client = req->client; QSIMPLEQ_INSERT_HEAD(&client->exp->requests, req, entry); if (client->nb_requests-- == MAX_NBD_REQUESTS) { qemu_notify_event(); } nbd_client_put(client); } NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, uint32_t nbdflags) { NBDExport *exp = g_malloc0(sizeof(NBDExport)); QSIMPLEQ_INIT(&exp->requests); exp->bs = bs; exp->dev_offset = dev_offset; exp->nbdflags = nbdflags; exp->size = size == -1 ? bdrv_getlength(bs) : size; return exp; } void nbd_export_close(NBDExport *exp) { while (!QSIMPLEQ_EMPTY(&exp->requests)) { NBDRequest *first = QSIMPLEQ_FIRST(&exp->requests); QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry); qemu_vfree(first->data); g_free(first); } bdrv_close(exp->bs); g_free(exp); } static int nbd_can_read(void *opaque); static void nbd_read(void *opaque); static void nbd_restart_write(void *opaque); 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); qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, nbd_restart_write, client); client->send_coroutine = qemu_coroutine_self(); 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; qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, 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; ssize_t rc; client->recv_coroutine = qemu_coroutine_self(); rc = nbd_receive_request(csock, request); if (rc < 0) { if (rc != -EAGAIN) { rc = -EIO; } goto out; } if (request->len > NBD_BUFFER_SIZE) { LOG("len (%u) is larger than max len (%u)", request->len, NBD_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"); if ((request->type & NBD_CMD_MASK_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; return rc; } static void nbd_trip(void *opaque) { NBDClient *client = opaque; NBDRequest *req = nbd_request_get(client); NBDExport *exp = client->exp; struct nbd_request request; struct nbd_reply reply; ssize_t ret; TRACE("Reading request."); 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; } if ((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 (request.type & NBD_CMD_MASK_COMMAND) { case NBD_CMD_READ: TRACE("Request type is READ"); if (request.type & NBD_CMD_FLAG_FUA) { ret = bdrv_co_flush(exp->bs); if (ret < 0) { LOG("flush failed"); reply.error = -ret; goto error_reply; } } ret = bdrv_read(exp->bs, (request.from + exp->dev_offset) / 512, req->data, request.len / 512); 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 = bdrv_write(exp->bs, (request.from + exp->dev_offset) / 512, req->data, request.len / 512); if (ret < 0) { LOG("writing to file failed"); reply.error = -ret; goto error_reply; } if (request.type & NBD_CMD_FLAG_FUA) { ret = bdrv_co_flush(exp->bs); 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 = bdrv_co_flush(exp->bs); 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 = bdrv_co_discard(exp->bs, (request.from + exp->dev_offset) / 512, request.len / 512); 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); nbd_client_close(client); } static int nbd_can_read(void *opaque) { NBDClient *client = opaque; return client->recv_coroutine || client->nb_requests < MAX_NBD_REQUESTS; } 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); } NBDClient *nbd_client_new(NBDExport *exp, int csock, void (*close)(NBDClient *)) { NBDClient *client; if (nbd_send_negotiate(csock, exp->size, exp->nbdflags) < 0) { return NULL; } client = g_malloc0(sizeof(NBDClient)); client->refcount = 1; client->exp = exp; client->sock = csock; client->close = close; qemu_co_mutex_init(&client->send_lock); qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, client); return client; }