diff options
| -rw-r--r-- | nbd.c | 169 |
1 files changed, 150 insertions, 19 deletions
@@ -238,11 +238,23 @@ int unix_socket_outgoing(const char *path) return unix_connect(path); } -/* Basic flow +/* Basic flow for negotiation Server Client - Negotiate + + or + + Server Client + Negotiate #1 + Option + Negotiate #2 + + ---- + + followed by + + Server Client Request Response Request @@ -250,20 +262,112 @@ int unix_socket_outgoing(const char *path) ... ... Request (type == 2) + */ +static int nbd_receive_options(NBDClient *client) +{ + int csock = client->sock; + char name[256]; + uint32_t tmp, length; + uint64_t magic; + int rc; + + /* Client sends: + [ 0 .. 3] reserved (0) + [ 4 .. 11] NBD_OPTS_MAGIC + [12 .. 15] NBD_OPT_EXPORT_NAME + [16 .. 19] length + [20 .. xx] export name (length bytes) + */ + + rc = -EINVAL; + if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { + LOG("read failed"); + goto fail; + } + TRACE("Checking reserved"); + if (tmp != 0) { + LOG("Bad reserved received"); + goto fail; + } + + if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { + LOG("read failed"); + goto fail; + } + TRACE("Checking reserved"); + if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) { + LOG("Bad magic received"); + goto fail; + } + + if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { + LOG("read failed"); + goto fail; + } + TRACE("Checking option"); + if (tmp != be32_to_cpu(NBD_OPT_EXPORT_NAME)) { + LOG("Bad option received"); + goto fail; + } + + if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) { + LOG("read failed"); + goto fail; + } + TRACE("Checking length"); + length = be32_to_cpu(length); + if (length > 255) { + LOG("Bad length received"); + goto fail; + } + if (read_sync(csock, name, length) != length) { + LOG("read failed"); + goto fail; + } + name[length] = '\0'; + + client->exp = nbd_export_find(name); + if (!client->exp) { + LOG("export not found"); + goto fail; + } + + QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); + nbd_export_get(client->exp); + + TRACE("Option negotiation succeeded."); + rc = 0; +fail: + return rc; +} + static int nbd_send_negotiate(NBDClient *client) { int csock = client->sock; char buf[8 + 8 + 8 + 128]; int rc; + const int myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | + NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA); - /* Negotiate - [ 0 .. 7] passwd ("NBDMAGIC") - [ 8 .. 15] magic (NBD_CLIENT_MAGIC) + /* Negotiation header without options: + [ 0 .. 7] passwd ("NBDMAGIC") + [ 8 .. 15] magic (NBD_CLIENT_MAGIC) [16 .. 23] size - [24 .. 27] flags - [28 .. 151] reserved (0) + [24 .. 25] server flags (0) + [24 .. 27] export flags + [28 .. 151] reserved (0) + + Negotiation header with options, part 1: + [ 0 .. 7] passwd ("NBDMAGIC") + [ 8 .. 15] magic (NBD_OPTS_MAGIC) + [16 .. 17] server flags (0) + + part 2 (after options are sent): + [18 .. 25] size + [26 .. 27] export flags + [28 .. 151] reserved (0) */ socket_set_block(csock); @@ -271,16 +375,39 @@ static int nbd_send_negotiate(NBDClient *client) TRACE("Beginning negotiation."); memcpy(buf, "NBDMAGIC", 8); - cpu_to_be64w((uint64_t*)(buf + 8), NBD_CLIENT_MAGIC); - cpu_to_be64w((uint64_t*)(buf + 16), client->exp->size); - cpu_to_be32w((uint32_t*)(buf + 24), - client->exp->nbdflags | NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | - NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA); + if (client->exp) { + assert ((client->exp->nbdflags & ~65535) == 0); + cpu_to_be64w((uint64_t*)(buf + 8), NBD_CLIENT_MAGIC); + cpu_to_be64w((uint64_t*)(buf + 16), client->exp->size); + cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags); + } else { + cpu_to_be64w((uint64_t*)(buf + 8), NBD_OPTS_MAGIC); + } memset(buf + 28, 0, 124); - if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { - LOG("write failed"); - goto fail; + if (client->exp) { + if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { + LOG("write failed"); + goto fail; + } + } else { + if (write_sync(csock, buf, 18) != 18) { + LOG("write failed"); + goto fail; + } + rc = nbd_receive_options(client); + if (rc < 0) { + LOG("option negotiation failed"); + goto fail; + } + + assert ((client->exp->nbdflags & ~65535) == 0); + cpu_to_be64w((uint64_t*)(buf + 18), client->exp->size); + cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags); + if (write_sync(csock, buf + 18, sizeof(buf) - 18) != sizeof(buf) - 18) { + LOG("write failed"); + goto fail; + } } TRACE("Negotiation succeeded."); @@ -673,8 +800,10 @@ void nbd_client_put(NBDClient *client) qemu_set_fd_handler2(client->sock, NULL, NULL, NULL, NULL); close(client->sock); client->sock = -1; - QTAILQ_REMOVE(&client->exp->clients, client, next); - nbd_export_put(client->exp); + if (client->exp) { + QTAILQ_REMOVE(&client->exp->clients, client, next); + nbd_export_put(client->exp); + } g_free(client); } } @@ -1100,7 +1229,9 @@ NBDClient *nbd_client_new(NBDExport *exp, int csock, qemu_co_mutex_init(&client->send_lock); qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, client); - QTAILQ_INSERT_TAIL(&exp->clients, client, next); - nbd_export_get(exp); + if (exp) { + QTAILQ_INSERT_TAIL(&exp->clients, client, next); + nbd_export_get(exp); + } return client; } |