/* * 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 <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> #include "qemu_socket.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_OPT_EXPORT_NAME (1 << 0) /* That's all folks */ #define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true) #define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false) size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read) { size_t offset = 0; while (offset < size) { ssize_t len; if (do_read) { len = recv(fd, buffer + offset, size - offset, 0); } else { len = send(fd, buffer + offset, size - offset, 0); } if (len == -1) errno = socket_error(); /* recoverable error */ if (len == -1 && (errno == EAGAIN || errno == EINTR)) { continue; } /* eof */ if (len == 0) { break; } /* unrecoverable error */ if (len == -1) { return 0; } offset += len; } return offset; } 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, SOCK_STREAM); } 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); } 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) */ int nbd_negotiate(int csock, off_t size) { char buf[8 + 8 + 8 + 128]; /* Negotiate [ 0 .. 7] passwd ("NBDMAGIC") [ 8 .. 15] magic (0x00420281861253) [16 .. 23] size [24 .. 151] reserved (0) */ TRACE("Beginning negotiation."); memcpy(buf, "NBDMAGIC", 8); cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL); cpu_to_be64w((uint64_t*)(buf + 16), size); memset(buf + 24, 0, 128); if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { LOG("write failed"); errno = EINVAL; return -1; } TRACE("Negotation succeeded."); return 0; } 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; TRACE("Receiving negotation."); if (read_sync(csock, buf, 8) != 8) { LOG("read failed"); errno = EINVAL; return -1; } buf[8] = '\0'; if (strlen(buf) == 0) { LOG("server connection closed"); errno = EINVAL; return -1; } 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"); errno = EINVAL; return -1; } if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { LOG("read failed"); errno = EINVAL; return -1; } 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"); errno = EINVAL; return -1; } if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { LOG("flags read failed"); errno = EINVAL; return -1; } *flags = be16_to_cpu(tmp) << 16; /* reserved for future use */ if (write_sync(csock, &reserved, sizeof(reserved)) != sizeof(reserved)) { LOG("write failed (reserved)"); errno = EINVAL; return -1; } /* write the export name */ magic = cpu_to_be64(magic); if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { LOG("write failed (magic)"); errno = EINVAL; return -1; } opt = cpu_to_be32(NBD_OPT_EXPORT_NAME); if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) { LOG("write failed (opt)"); errno = EINVAL; return -1; } namesize = cpu_to_be32(strlen(name)); if (write_sync(csock, &namesize, sizeof(namesize)) != sizeof(namesize)) { LOG("write failed (namesize)"); errno = EINVAL; return -1; } if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) { LOG("write failed (name)"); errno = EINVAL; return -1; } } else { TRACE("Checking magic (cli_magic)"); if (magic != 0x00420281861253LL) { LOG("Bad magic received"); errno = EINVAL; return -1; } } if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) { LOG("read failed"); errno = EINVAL; return -1; } *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)"); errno = EINVAL; return -1; } *flags = be32_to_cpup(flags); } else { if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { LOG("read failed (tmp)"); errno = EINVAL; return -1; } *flags |= be32_to_cpu(tmp); } if (read_sync(csock, &buf, 124) != 124) { LOG("read failed (buf)"); errno = EINVAL; return -1; } return 0; } #ifndef _WIN32 int nbd_init(int fd, int csock, off_t size, size_t blocksize) { TRACE("Setting block size to %lu", (unsigned long)blocksize); if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) { int serrno = errno; LOG("Failed setting NBD block size"); errno = serrno; return -1; } TRACE("Setting size to %zd block(s)", (size_t)(size / blocksize)); if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) == -1) { int serrno = errno; LOG("Failed setting size (in blocks)"); errno = serrno; return -1; } TRACE("Clearing NBD socket"); if (ioctl(fd, NBD_CLEAR_SOCK) == -1) { int serrno = errno; LOG("Failed clearing NBD socket"); errno = serrno; return -1; } TRACE("Setting NBD socket"); if (ioctl(fd, NBD_SET_SOCK, csock) == -1) { int serrno = errno; LOG("Failed to set NBD socket"); errno = serrno; return -1; } 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); 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, off_t size, size_t blocksize) { errno = ENOTSUP; return -1; } int nbd_disconnect(int fd) { errno = ENOTSUP; return -1; } int nbd_client(int fd) { errno = ENOTSUP; return -1; } #endif int nbd_send_request(int csock, struct nbd_request *request) { uint8_t buf[4 + 4 + 8 + 8 + 4]; 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); if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { LOG("writing to socket failed"); errno = EINVAL; return -1; } return 0; } static int nbd_receive_request(int csock, struct nbd_request *request) { uint8_t buf[4 + 4 + 8 + 8 + 4]; uint32_t magic; if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { LOG("read failed"); errno = EINVAL; return -1; } /* 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); errno = EINVAL; return -1; } return 0; } int nbd_receive_reply(int csock, struct nbd_reply *reply) { uint8_t buf[NBD_REPLY_SIZE]; uint32_t magic; memset(buf, 0xAA, sizeof(buf)); if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { LOG("read failed"); errno = EINVAL; return -1; } /* 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); errno = EINVAL; return -1; } return 0; } static int nbd_send_reply(int csock, struct nbd_reply *reply) { uint8_t buf[4 + 4 + 8]; /* 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"); if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { LOG("writing to socket failed"); errno = EINVAL; return -1; } return 0; } int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly, uint8_t *data, int data_size) { struct nbd_request request; struct nbd_reply reply; TRACE("Reading request."); if (nbd_receive_request(csock, &request) == -1) return -1; if (request.len + NBD_REPLY_SIZE > data_size) { LOG("len (%u) is larger than max len (%u)", request.len + NBD_REPLY_SIZE, data_size); errno = EINVAL; return -1; } if ((request.from + request.len) < request.from) { LOG("integer overflow detected! " "you're probably being attacked"); errno = EINVAL; return -1; } if ((request.from + request.len) > size) { LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64 ", Offset: %" PRIu64 "\n", request.from, request.len, (uint64_t)size, dev_offset); LOG("requested operation past EOF--bad client?"); errno = EINVAL; return -1; } TRACE("Decoding type"); reply.handle = request.handle; reply.error = 0; switch (request.type) { case NBD_CMD_READ: TRACE("Request type is READ"); if (bdrv_read(bs, (request.from + dev_offset) / 512, data + NBD_REPLY_SIZE, request.len / 512) == -1) { LOG("reading from file failed"); errno = EINVAL; return -1; } *offset += request.len; TRACE("Read %u byte(s)", request.len); /* Reply [ 0 .. 3] magic (NBD_REPLY_MAGIC) [ 4 .. 7] error (0 == no error) [ 7 .. 15] handle */ cpu_to_be32w((uint32_t*)data, NBD_REPLY_MAGIC); cpu_to_be32w((uint32_t*)(data + 4), reply.error); cpu_to_be64w((uint64_t*)(data + 8), reply.handle); TRACE("Sending data to client"); if (write_sync(csock, data, request.len + NBD_REPLY_SIZE) != request.len + NBD_REPLY_SIZE) { LOG("writing to socket failed"); errno = EINVAL; return -1; } break; case NBD_CMD_WRITE: TRACE("Request type is WRITE"); TRACE("Reading %u byte(s)", request.len); if (read_sync(csock, data, request.len) != request.len) { LOG("reading from socket failed"); errno = EINVAL; return -1; } if (readonly) { TRACE("Server is read-only, return error"); reply.error = 1; } else { TRACE("Writing to device"); if (bdrv_write(bs, (request.from + dev_offset) / 512, data, request.len / 512) == -1) { LOG("writing to file failed"); errno = EINVAL; return -1; } *offset += request.len; } if (nbd_send_reply(csock, &reply) == -1) return -1; break; case NBD_CMD_DISC: TRACE("Request type is DISCONNECT"); errno = 0; return 1; default: LOG("invalid request type (%u) received", request.type); errno = EINVAL; return -1; } TRACE("Request/Reply complete"); return 0; }