Commit 1d45f8b5 authored by Laurent Vivier's avatar Laurent Vivier Committed by Kevin Wolf
Browse files

nbd: Introduce NBD named exports. 



This patch allows to connect Qemu using NBD protocol to an nbd-server
using named exports.

For instance, if on the host "isoserver", in /etc/nbd-server/config, you have:

[generic]
[debian-500-ppc-netinst]
        exportname = /ISO/debian-500-powerpc-netinst.iso
[Fedora-10-ppc-netinst]
        exportname = /ISO/Fedora-10-ppc-netinst.iso

You can connect to it, using:

    qemu -cdrom nbd:isoserver:exportname=debian-500-ppc-netinst
    qemu -cdrom nbd:isoserver:exportname=Fedora-10-ppc-netinst

NOTE: you need at least nbd-server 2.9.18

Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 2aa326be

block/nbd.c

+49 −19
Original line number Diff line number Diff line
@@ -33,6 +33,8 @@ 
#include <sys/types.h>

#include <unistd.h>



#define EN_OPTSTR ":exportname="



typedef struct BDRVNBDState {

    int sock;

    off_t size;
@@ -42,55 +44,83 @@ typedef struct BDRVNBDState { 
static int nbd_open(BlockDriverState *bs, const char* filename, int flags)

{

    BDRVNBDState *s = bs->opaque;

    uint32_t nbdflags;



    char *file;

    char *name;

    const char *host;

    const char *unixpath;

    int sock;

    off_t size;

    size_t blocksize;

    int ret;

    int err = -EINVAL;



    file = qemu_strdup(filename);



    if (!strstart(filename, "nbd:", &host))

        return -EINVAL;

    name = strstr(file, EN_OPTSTR);

    if (name) {

        if (name[strlen(EN_OPTSTR)] == 0) {

            goto out;

        }

        name[0] = 0;

        name += strlen(EN_OPTSTR);

    }



    if (!strstart(file, "nbd:", &host)) {

        goto out;

    }



    if (strstart(host, "unix:", &unixpath)) {



        if (unixpath[0] != '/')

            return -EINVAL;

        if (unixpath[0] != '/') {

            goto out;

        }



        sock = unix_socket_outgoing(unixpath);



    } else {

        uint16_t port;

        uint16_t port = NBD_DEFAULT_PORT;

        char *p, *r;

        char hostname[128];



        pstrcpy(hostname, 128, host);



        p = strchr(hostname, ':');

        if (p == NULL)

            return -EINVAL;



        if (p != NULL) {

            *p = '\0';

            p++;



            port = strtol(p, &r, 0);

        if (r == p)

            return -EINVAL;

            if (r == p) {

                goto out;

            }

        } else if (name == NULL) {

            goto out;

        }



        sock = tcp_socket_outgoing(hostname, port);

    }



    if (sock == -1)

        return -errno;

    if (sock == -1) {

        err = -errno;

        goto out;

    }



    ret = nbd_receive_negotiate(sock, &size, &blocksize);

    if (ret == -1)

        return -errno;

    ret = nbd_receive_negotiate(sock, name, &nbdflags, &size, &blocksize);

    if (ret == -1) {

        err = -errno;

        goto out;

    }



    s->sock = sock;

    s->size = size;

    s->blocksize = blocksize;

    err = 0;



    return 0;

out:

    qemu_free(file);

    return err;

}



static int nbd_read(BlockDriverState *bs, int64_t sector_num,

nbd.c

+106 −12
Original line number Diff line number Diff line
@@ -62,6 +62,8 @@ 
#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)
@@ -296,22 +298,27 @@ int nbd_negotiate(int csock, off_t size) 
	return 0;

}



int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)

int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,

                          off_t *size, size_t *blocksize)

{

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

	uint64_t magic;

	char buf[256];

	uint64_t magic, s;

	uint16_t tmp;



	TRACE("Receiving negotation.");



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

	if (read_sync(csock, buf, 8) != 8) {

		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;

	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] : '.',
@@ -322,8 +329,6 @@ int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize) 
	      qemu_isprint(buf[5]) ? buf[5] : '.',

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

	      qemu_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");
@@ -331,13 +336,102 @@ int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize) 
		return -1;

	}



	TRACE("Checking magic");

	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;

}

nbd.h

+4 −1
Original line number Diff line number Diff line
@@ -42,6 +42,8 @@ enum { 
    NBD_CMD_DISC = 2

};



#define NBD_DEFAULT_PORT	10809



size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);

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

int tcp_socket_incoming(const char *address, uint16_t port);
@@ -49,7 +51,8 @@ int unix_socket_outgoing(const char *path); 
int unix_socket_incoming(const char *path);



int nbd_negotiate(int csock, off_t size);

int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize);

int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,

                          off_t *size, size_t *blocksize);

int nbd_init(int fd, int csock, off_t size, size_t blocksize);

int nbd_send_request(int csock, struct nbd_request *request);

int nbd_receive_reply(int csock, struct nbd_reply *reply);

qemu-doc.texi

+7 −0
Original line number Diff line number Diff line
@@ -620,6 +620,13 @@ qemu linux1.img -hdb nbd:unix:/tmp/my_socket 
qemu linux2.img -hdb nbd:unix:/tmp/my_socket

@end example



If the nbd-server uses named exports (since NBD 2.9.18), you must use the

"exportname" option:

@example

qemu -cdrom nbd:localhost:exportname=debian-500-ppc-netinst

qemu -cdrom nbd:localhost:exportname=openSUSE-11.1-ppc-netinst

@end example



@node pcsys_network

@section Network emulation

qemu-nbd.c

+3 −1
Original line number Diff line number Diff line
@@ -230,6 +230,7 @@ int main(int argc, char **argv) 
    int nb_fds = 0;

    int max_fd;

    int persistent = 0;

    uint32_t nbdflags;



    while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {

        switch (ch) {
@@ -398,7 +399,8 @@ int main(int argc, char **argv) 
                goto out;

            }



            ret = nbd_receive_negotiate(sock, &size, &blocksize);

            ret = nbd_receive_negotiate(sock, NULL, &nbdflags,

					&size, &blocksize);

            if (ret == -1) {

                ret = 1;

                goto out;