563 lines
12 KiB
C
563 lines
12 KiB
C
/*\
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* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
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*
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* Network Block Device
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; under version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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\*/
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#include "nbd.h"
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#include <errno.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <ctype.h>
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#include <inttypes.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#include <netinet/in.h>
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#include <netinet/tcp.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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extern int verbose;
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#define LOG(msg, ...) do { \
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fprintf(stderr, "%s:%s():L%d: " msg "\n", \
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__FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
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} while(0)
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#define TRACE(msg, ...) do { \
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if (verbose) LOG(msg, ## __VA_ARGS__); \
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} while(0)
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/* This is all part of the "official" NBD API */
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#define NBD_REQUEST_MAGIC 0x25609513
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#define NBD_REPLY_MAGIC 0x67446698
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#define NBD_SET_SOCK _IO(0xab, 0)
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#define NBD_SET_BLKSIZE _IO(0xab, 1)
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#define NBD_SET_SIZE _IO(0xab, 2)
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#define NBD_DO_IT _IO(0xab, 3)
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#define NBD_CLEAR_SOCK _IO(0xab, 4)
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#define NBD_CLEAR_QUE _IO(0xab, 5)
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#define NBD_PRINT_DEBUG _IO(0xab, 6)
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#define NBD_SET_SIZE_BLOCKS _IO(0xab, 7)
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#define NBD_DISCONNECT _IO(0xab, 8)
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/* That's all folks */
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#define read_sync(fd, buffer, size) wr_sync(fd, buffer, size, true)
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#define write_sync(fd, buffer, size) wr_sync(fd, buffer, size, false)
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static size_t wr_sync(int fd, void *buffer, size_t size, bool do_read)
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{
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size_t offset = 0;
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while (offset < size) {
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ssize_t len;
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if (do_read) {
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len = read(fd, buffer + offset, size - offset);
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} else {
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len = write(fd, buffer + offset, size - offset);
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}
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/* recoverable error */
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if (len == -1 && errno == EAGAIN) {
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continue;
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}
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/* eof */
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if (len == 0) {
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break;
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}
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/* unrecoverable error */
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if (len == -1) {
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return 0;
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}
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offset += len;
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}
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return offset;
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}
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static int tcp_socket_outgoing(const char *address, uint16_t port)
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{
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int s;
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struct in_addr in;
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struct sockaddr_in addr;
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int serrno;
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s = socket(PF_INET, SOCK_STREAM, 0);
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if (s == -1) {
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return -1;
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}
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if (inet_aton(address, &in) == 0) {
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struct hostent *ent;
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ent = gethostbyname(address);
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if (ent == NULL) {
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goto error;
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}
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memcpy(&in, ent->h_addr, sizeof(in));
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}
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addr.sin_family = AF_INET;
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addr.sin_port = htons(port);
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memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
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if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
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goto error;
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}
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return s;
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error:
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serrno = errno;
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close(s);
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errno = serrno;
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return -1;
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}
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int tcp_socket_incoming(const char *address, uint16_t port)
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{
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int s;
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struct in_addr in;
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struct sockaddr_in addr;
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int serrno;
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int opt;
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s = socket(PF_INET, SOCK_STREAM, 0);
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if (s == -1) {
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return -1;
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}
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if (inet_aton(address, &in) == 0) {
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struct hostent *ent;
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ent = gethostbyname(address);
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if (ent == NULL) {
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goto error;
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}
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memcpy(&in, ent->h_addr, sizeof(in));
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}
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addr.sin_family = AF_INET;
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addr.sin_port = htons(port);
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memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
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opt = 1;
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if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) == -1) {
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goto error;
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}
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if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
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goto error;
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}
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if (listen(s, 128) == -1) {
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goto error;
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}
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return s;
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error:
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serrno = errno;
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close(s);
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errno = serrno;
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return -1;
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}
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int unix_socket_incoming(const char *path)
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{
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int s;
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struct sockaddr_un addr;
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int serrno;
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s = socket(PF_UNIX, SOCK_STREAM, 0);
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if (s == -1) {
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return -1;
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}
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memset(&addr, 0, sizeof(addr));
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addr.sun_family = AF_UNIX;
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pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
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if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
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goto error;
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}
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if (listen(s, 128) == -1) {
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goto error;
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}
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return s;
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error:
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serrno = errno;
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close(s);
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errno = serrno;
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return -1;
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}
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int unix_socket_outgoing(const char *path)
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{
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int s;
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struct sockaddr_un addr;
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int serrno;
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s = socket(PF_UNIX, SOCK_STREAM, 0);
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if (s == -1) {
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return -1;
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}
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memset(&addr, 0, sizeof(addr));
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addr.sun_family = AF_UNIX;
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pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
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if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
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goto error;
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}
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return s;
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error:
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serrno = errno;
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close(s);
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errno = serrno;
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return -1;
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}
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/* Basic flow
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Server Client
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Negotiate
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Request
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Response
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Request
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Response
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...
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...
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Request (type == 2)
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*/
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int nbd_negotiate(BlockDriverState *bs, int csock, off_t size)
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{
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char buf[8 + 8 + 8 + 128];
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/* Negotiate
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[ 0 .. 7] passwd ("NBDMAGIC")
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[ 8 .. 15] magic (0x00420281861253)
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[16 .. 23] size
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[24 .. 151] reserved (0)
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*/
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TRACE("Beginning negotiation.");
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memcpy(buf, "NBDMAGIC", 8);
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cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
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cpu_to_be64w((uint64_t*)(buf + 16), size);
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memset(buf + 24, 0, 128);
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if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
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LOG("write failed");
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errno = EINVAL;
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return -1;
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}
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TRACE("Negotation succeeded.");
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return 0;
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}
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int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
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{
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char buf[8 + 8 + 8 + 128];
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uint64_t magic;
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TRACE("Receiving negotation.");
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if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
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LOG("read failed");
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errno = EINVAL;
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return -1;
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}
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magic = be64_to_cpup((uint64_t*)(buf + 8));
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*size = be64_to_cpup((uint64_t*)(buf + 16));
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*blocksize = 1024;
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TRACE("Magic is %c%c%c%c%c%c%c%c",
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isprint(buf[0]) ? buf[0] : '.',
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isprint(buf[1]) ? buf[1] : '.',
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isprint(buf[2]) ? buf[2] : '.',
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isprint(buf[3]) ? buf[3] : '.',
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isprint(buf[4]) ? buf[4] : '.',
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isprint(buf[5]) ? buf[5] : '.',
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isprint(buf[6]) ? buf[6] : '.',
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isprint(buf[7]) ? buf[7] : '.');
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TRACE("Magic is 0x%" PRIx64, magic);
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TRACE("Size is %" PRIu64, *size);
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if (memcmp(buf, "NBDMAGIC", 8) != 0) {
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LOG("Invalid magic received");
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errno = EINVAL;
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return -1;
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}
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TRACE("Checking magic");
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if (magic != 0x00420281861253LL) {
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LOG("Bad magic received");
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errno = EINVAL;
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return -1;
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}
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return 0;
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}
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int nbd_init(int fd, int csock, off_t size, size_t blocksize)
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{
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TRACE("Setting block size to %lu", (unsigned long)blocksize);
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if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
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int serrno = errno;
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LOG("Failed setting NBD block size");
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errno = serrno;
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return -1;
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}
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TRACE("Setting size to %llu block(s)",
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(unsigned long long)(size / blocksize));
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if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) == -1) {
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int serrno = errno;
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LOG("Failed setting size (in blocks)");
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errno = serrno;
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return -1;
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}
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TRACE("Clearing NBD socket");
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if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
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int serrno = errno;
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LOG("Failed clearing NBD socket");
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errno = serrno;
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return -1;
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}
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TRACE("Setting NBD socket");
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if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
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int serrno = errno;
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LOG("Failed to set NBD socket");
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errno = serrno;
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return -1;
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}
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TRACE("Negotiation ended");
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return 0;
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}
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int nbd_disconnect(int fd)
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{
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ioctl(fd, NBD_CLEAR_QUE);
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ioctl(fd, NBD_DISCONNECT);
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ioctl(fd, NBD_CLEAR_SOCK);
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return 0;
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}
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int nbd_client(int fd, int csock)
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{
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int ret;
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int serrno;
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TRACE("Doing NBD loop");
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ret = ioctl(fd, NBD_DO_IT);
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serrno = errno;
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TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
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TRACE("Clearing NBD queue");
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ioctl(fd, NBD_CLEAR_QUE);
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TRACE("Clearing NBD socket");
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ioctl(fd, NBD_CLEAR_SOCK);
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errno = serrno;
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return ret;
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}
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int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly)
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{
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#ifndef _REENTRANT
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static uint8_t data[1024 * 1024]; // keep this off of the stack
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#else
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uint8_t data[1024 * 1024];
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#endif
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uint8_t buf[4 + 4 + 8 + 8 + 4];
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uint32_t magic;
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uint32_t type;
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uint64_t from;
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uint32_t len;
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TRACE("Reading request.");
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if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
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LOG("read failed");
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errno = EINVAL;
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return -1;
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}
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/* Request
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[ 0 .. 3] magic (NBD_REQUEST_MAGIC)
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[ 4 .. 7] type (0 == READ, 1 == WRITE)
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[ 8 .. 15] handle
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[16 .. 23] from
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[24 .. 27] len
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*/
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magic = be32_to_cpup((uint32_t*)buf);
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type = be32_to_cpup((uint32_t*)(buf + 4));
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from = be64_to_cpup((uint64_t*)(buf + 16));
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len = be32_to_cpup((uint32_t*)(buf + 24));
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TRACE("Got request: "
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"{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
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magic, type, from, len);
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if (magic != NBD_REQUEST_MAGIC) {
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LOG("invalid magic (got 0x%x)", magic);
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errno = EINVAL;
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return -1;
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}
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if (len > sizeof(data)) {
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LOG("len (%u) is larger than max len (%lu)",
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len, (unsigned long)sizeof(data));
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errno = EINVAL;
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return -1;
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}
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if ((from + len) < from) {
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LOG("integer overflow detected! "
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"you're probably being attacked");
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errno = EINVAL;
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return -1;
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}
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if ((from + len) > size) {
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LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
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", Offset: %" PRIu64 "\n",
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from, len, size, dev_offset);
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LOG("requested operation past EOF--bad client?");
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errno = EINVAL;
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return -1;
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}
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/* Reply
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[ 0 .. 3] magic (NBD_REPLY_MAGIC)
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[ 4 .. 7] error (0 == no error)
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[ 7 .. 15] handle
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*/
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cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
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cpu_to_be32w((uint32_t*)(buf + 4), 0);
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TRACE("Decoding type");
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switch (type) {
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case 0:
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TRACE("Request type is READ");
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if (bdrv_read(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
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LOG("reading from file failed");
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errno = EINVAL;
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return -1;
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}
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*offset += len;
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TRACE("Read %u byte(s)", len);
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TRACE("Sending OK response");
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if (write_sync(csock, buf, 16) != 16) {
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LOG("writing to socket failed");
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errno = EINVAL;
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return -1;
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}
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TRACE("Sending data to client");
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if (write_sync(csock, data, len) != len) {
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LOG("writing to socket failed");
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errno = EINVAL;
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return -1;
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}
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break;
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case 1:
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TRACE("Request type is WRITE");
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TRACE("Reading %u byte(s)", len);
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if (read_sync(csock, data, len) != len) {
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LOG("reading from socket failed");
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errno = EINVAL;
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return -1;
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}
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if (readonly) {
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TRACE("Server is read-only, return error");
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cpu_to_be32w((uint32_t*)(buf + 4), 1);
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} else {
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TRACE("Writing to device");
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if (bdrv_write(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
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LOG("writing to file failed");
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errno = EINVAL;
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return -1;
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}
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*offset += len;
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}
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TRACE("Sending response to client");
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if (write_sync(csock, buf, 16) != 16) {
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LOG("writing to socket failed");
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errno = EINVAL;
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return -1;
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}
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break;
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case 2:
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TRACE("Request type is DISCONNECT");
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errno = 0;
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return 1;
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default:
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LOG("invalid request type (%u) received", type);
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errno = EINVAL;
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return -1;
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}
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TRACE("Request/Reply complete");
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return 0;
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}
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