diff options
Diffstat (limited to 'nbd.c')
| -rw-r--r-- | nbd.c | 151 |
1 files changed, 102 insertions, 49 deletions
@@ -56,7 +56,11 @@ __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \ } while(0) -/* This is all part of the "official" NBD API */ +/* This is all part of the "official" NBD API. + * + * The most up-to-date documentation is available at: + * https://github.com/yoe/nbd/blob/master/doc/proto.txt + */ #define NBD_REQUEST_SIZE (4 + 4 + 8 + 8 + 4) #define NBD_REPLY_SIZE (4 + 4 + 8) @@ -64,6 +68,7 @@ #define NBD_REPLY_MAGIC 0x67446698 #define NBD_OPTS_MAGIC 0x49484156454F5054LL #define NBD_CLIENT_MAGIC 0x0000420281861253LL +#define NBD_REP_MAGIC 0x3e889045565a9LL #define NBD_SET_SOCK _IO(0xab, 0) #define NBD_SET_BLKSIZE _IO(0xab, 1) @@ -77,7 +82,8 @@ #define NBD_SET_TIMEOUT _IO(0xab, 9) #define NBD_SET_FLAGS _IO(0xab, 10) -#define NBD_OPT_EXPORT_NAME (1 << 0) +#define NBD_OPT_EXPORT_NAME (1) +#define NBD_OPT_ABORT (2) /* Definitions for opaque data types */ @@ -215,59 +221,43 @@ static ssize_t write_sync(int fd, void *buffer, size_t size) */ -static int nbd_receive_options(NBDClient *client) +static int nbd_send_rep(int csock, uint32_t type, uint32_t opt) { - 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) - */ + uint32_t len; - rc = -EINVAL; - if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { - LOG("read failed"); - goto fail; + magic = cpu_to_be64(NBD_REP_MAGIC); + if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { + LOG("write failed (rep magic)"); + return -EINVAL; } - TRACE("Checking reserved"); - if (tmp != 0) { - LOG("Bad reserved received"); - goto fail; + opt = cpu_to_be32(opt); + if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) { + LOG("write failed (rep opt)"); + return -EINVAL; } - - if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { - LOG("read failed"); - goto fail; + type = cpu_to_be32(type); + if (write_sync(csock, &type, sizeof(type)) != sizeof(type)) { + LOG("write failed (rep type)"); + return -EINVAL; } - TRACE("Checking reserved"); - if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) { - LOG("Bad magic received"); - goto fail; + len = cpu_to_be32(0); + if (write_sync(csock, &len, sizeof(len)) != sizeof(len)) { + LOG("write failed (rep data length)"); + return -EINVAL; } + return 0; +} - 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; - } +static int nbd_handle_export_name(NBDClient *client, uint32_t length) +{ + int rc = -EINVAL, csock = client->sock; + char name[256]; - if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) { - LOG("read failed"); - goto fail; - } + /* Client sends: + [20 .. xx] export name (length bytes) + */ TRACE("Checking length"); - length = be32_to_cpu(length); if (length > 255) { LOG("Bad length received"); goto fail; @@ -286,13 +276,75 @@ static int nbd_receive_options(NBDClient *client) 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_receive_options(NBDClient *client) +{ + while (1) { + int csock = client->sock; + uint32_t tmp, length; + uint64_t magic; + + /* Client sends: + [ 0 .. 3] client flags + [ 4 .. 11] NBD_OPTS_MAGIC + [12 .. 15] NBD option + [16 .. 19] length + ... Rest of request + */ + + if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { + LOG("read failed"); + return -EINVAL; + } + TRACE("Checking client flags"); + tmp = be32_to_cpu(tmp); + if (tmp != 0 && tmp != NBD_FLAG_C_FIXED_NEWSTYLE) { + LOG("Bad client flags received"); + return -EINVAL; + } + + if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { + LOG("read failed"); + return -EINVAL; + } + TRACE("Checking opts magic"); + if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) { + LOG("Bad magic received"); + return -EINVAL; + } + + if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { + LOG("read failed"); + return -EINVAL; + } + + if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) { + LOG("read failed"); + return -EINVAL; + } + length = be32_to_cpu(length); + + TRACE("Checking option"); + switch (be32_to_cpu(tmp)) { + case NBD_OPT_ABORT: + return -EINVAL; + + case NBD_OPT_EXPORT_NAME: + return nbd_handle_export_name(client, length); + + default: + tmp = be32_to_cpu(tmp); + LOG("Unsupported option 0x%x", tmp); + nbd_send_rep(client->sock, NBD_REP_ERR_UNSUP, tmp); + return -EINVAL; + } + } +} + static int nbd_send_negotiate(NBDClient *client) { int csock = client->sock; @@ -333,6 +385,7 @@ static int nbd_send_negotiate(NBDClient *client) cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags); } else { cpu_to_be64w((uint64_t*)(buf + 8), NBD_OPTS_MAGIC); + cpu_to_be16w((uint16_t *)(buf + 16), NBD_FLAG_FIXED_NEWSTYLE); } if (client->exp) { @@ -346,7 +399,7 @@ static int nbd_send_negotiate(NBDClient *client) goto fail; } rc = nbd_receive_options(client); - if (rc < 0) { + if (rc != 0) { LOG("option negotiation failed"); goto fail; } @@ -1174,7 +1227,7 @@ NBDClient *nbd_client_new(NBDExport *exp, int csock, client->refcount = 1; client->exp = exp; client->sock = csock; - if (nbd_send_negotiate(client) < 0) { + if (nbd_send_negotiate(client)) { g_free(client); return NULL; } |