Archipelago » qemu

/*\

 *  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, write to the Free Software

 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

\*/

#include "nbd.h"

#include <errno.h>

#include <string.h>

#include <sys/ioctl.h>

#include <ctype.h>

#include <inttypes.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <netinet/tcp.h>

#include <arpa/inet.h>

#include <netdb.h>

extern int verbose;

#define LOG(msg, ...) do { \

    fprintf(stderr, "%s:%s():L%d: " msg "\n", \

            __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \

} while(0)

#define TRACE(msg, ...) do { \

    if (verbose) LOG(msg, ## __VA_ARGS__); \

} while(0)

/* This is all part of the "official" NBD API */

#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)

/* That's all folks */

#define read_sync(fd, buffer, size) wr_sync(fd, buffer, size, true)

#define write_sync(fd, buffer, size) wr_sync(fd, buffer, size, false)

static size_t 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 = read(fd, buffer + offset, size - offset);

        } else {

            len = write(fd, buffer + offset, size - offset);

        }

        /* recoverable error */

        if (len == -1 && errno == EAGAIN) {

            continue;

        }

        /* eof */

        if (len == 0) {

            break;

        }

        /* unrecoverable error */

        if (len == -1) {

            return 0;

        }

        offset += len;

    }

    return offset;

}

static int tcp_socket_outgoing(const char *address, uint16_t port)

{

    int s;

    struct in_addr in;

    struct sockaddr_in addr;

    int serrno;

    s = socket(PF_INET, SOCK_STREAM, 0);

    if (s == -1) {

        return -1;

    }

    if (inet_aton(address, &in) == 0) {

        struct hostent *ent;

        ent = gethostbyname(address);

        if (ent == NULL) {

            goto error;

        }

        memcpy(&in, ent->h_addr, sizeof(in));

    }

    addr.sin_family = AF_INET;

    addr.sin_port = htons(port);

    memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));

    if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {

        goto error;

    }

    return s;

error:

    serrno = errno;

    close(s);

    errno = serrno;

    return -1;

}

int tcp_socket_incoming(const char *address, uint16_t port)

{

    int s;

    struct in_addr in;

    struct sockaddr_in addr;

    int serrno;

    int opt;

    s = socket(PF_INET, SOCK_STREAM, 0);

    if (s == -1) {

        return -1;

    }

    if (inet_aton(address, &in) == 0) {

        struct hostent *ent;

        ent = gethostbyname(address);

        if (ent == NULL) {

            goto error;

        }

        memcpy(&in, ent->h_addr, sizeof(in));

    }

    addr.sin_family = AF_INET;

    addr.sin_port = htons(port);

    memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));

    opt = 1;

    if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) == -1) {

        goto error;

    }

    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {

        goto error;

    }

    if (listen(s, 128) == -1) {

        goto error;

    }

    return s;

error:

    serrno = errno;

    close(s);

    errno = serrno;

    return -1;

}

/* Basic flow

   Server         Client

   Negotiate

                  Request

   Response

                  Request

   Response

                  ...

   ...

                  Request (type == 2)

*/

int nbd_negotiate(BlockDriverState *bs, 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 fd, int csock)

{

        char buf[8 + 8 + 8 + 128];

        uint64_t magic;

        off_t size;

        size_t blocksize;

        TRACE("Receiving negotation.");

        if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {

                LOG("read failed");

                errno = EINVAL;

                return -1;

        }

        magic = be64_to_cpup((uint64_t*)(buf + 8));

        size = be64_to_cpup((uint64_t*)(buf + 16));

        blocksize = 1024;

        TRACE("Magic is %c%c%c%c%c%c%c%c",

              isprint(buf[0]) ? buf[0] : '.',

              isprint(buf[1]) ? buf[1] : '.',

              isprint(buf[2]) ? buf[2] : '.',

              isprint(buf[3]) ? buf[3] : '.',

              isprint(buf[4]) ? buf[4] : '.',

              isprint(buf[5]) ? buf[5] : '.',

              isprint(buf[6]) ? buf[6] : '.',

              isprint(buf[7]) ? buf[7] : '.');

        TRACE("Magic is 0x%" PRIx64, magic);

        TRACE("Size is %" PRIu64, size);

        if (memcmp(buf, "NBDMAGIC", 8) != 0) {

                LOG("Invalid magic received");

                errno = EINVAL;

                return -1;

        }

        TRACE("Checking magic");

        if (magic != 0x00420281861253LL) {

                LOG("Bad magic received");

                errno = EINVAL;

                return -1;

        }

        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 %llu block(s)",

              (unsigned long long)(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 csock)

{

        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;

}

int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly)

{

#ifndef _REENTRANT

        static uint8_t data[1024 * 1024]; // keep this off of the stack

#else

        uint8_t data[1024 * 1024];

#endif

        uint8_t buf[4 + 4 + 8 + 8 + 4];

        uint32_t magic;

        uint32_t type;

        uint64_t from;

        uint32_t len;

        TRACE("Reading request.");

        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);

        type  = be32_to_cpup((uint32_t*)(buf + 4));

        from  = be64_to_cpup((uint64_t*)(buf + 16));

        len   = be32_to_cpup((uint32_t*)(buf + 24));

        TRACE("Got request: "

              "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",

              magic, type, from, len);

        if (magic != NBD_REQUEST_MAGIC) {

                LOG("invalid magic (got 0x%x)", magic);

                errno = EINVAL;

                return -1;

        }

        if (len > sizeof(data)) {

                LOG("len (%u) is larger than max len (%u)",

                    len, sizeof(data));

                errno = EINVAL;

                return -1;

        }

        if ((from + len) < from) {

                LOG("integer overflow detected! "

                    "you're probably being attacked");

                errno = EINVAL;

                return -1;

        }

        if ((from + len) > size) {

                LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64

                    ", Offset: %" PRIu64 "\n",

                     from, len, size, dev_offset);

                LOG("requested operation past EOF--bad client?");

                errno = EINVAL;

                return -1;

        }

        /* 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), 0);

        TRACE("Decoding type");

        switch (type) {

        case 0:

                TRACE("Request type is READ");

                if (bdrv_read(bs, (from + dev_offset) / 512, data, len / 512) == -1) {

                        LOG("reading from file failed");

                        errno = EINVAL;

                        return -1;

                }

                *offset += len;

                TRACE("Read %u byte(s)", len);

                TRACE("Sending OK response");

                if (write_sync(csock, buf, 16) != 16) {

                        LOG("writing to socket failed");

                        errno = EINVAL;

                        return -1;

                }

                TRACE("Sending data to client");

                if (write_sync(csock, data, len) != len) {

                        LOG("writing to socket failed");

                        errno = EINVAL;

                        return -1;

                }

                break;

        case 1:

                TRACE("Request type is WRITE");

                TRACE("Reading %u byte(s)", len);

                if (read_sync(csock, data, len) != len) {

                        LOG("reading from socket failed");

                        errno = EINVAL;

                        return -1;

                }

                if (readonly) {

                        TRACE("Server is read-only, return error");

                        cpu_to_be32w((uint32_t*)(buf + 4), 1);

                } else {

                        TRACE("Writing to device");

                        if (bdrv_write(bs, (from + dev_offset) / 512, data, len / 512) == -1) {

                                LOG("writing to file failed");

                                errno = EINVAL;

                                return -1;

                        }

                        *offset += len;

                }

                TRACE("Sending response to client");

                if (write_sync(csock, buf, 16) != 16) {

                        LOG("writing to socket failed");

                        errno = EINVAL;

                        return -1;

                }

                break;

        case 2:

                TRACE("Request type is DISCONNECT");

                errno = 0;

                return 1;

        default:

                LOG("invalid request type (%u) received", type);

                errno = EINVAL;

                return -1;

        }

        TRACE("Request/Reply complete");

        return 0;

}