int nbd_receive_negotiate(QIOChannel *ioc, const char *name, QCryptoTLSCreds *tlscreds, const char *hostname, QIOChannel **outioc, NBDExportInfo *info, Error **errp) { char buf[256]; uint64_t magic; int rc; bool zeroes = true; trace_nbd_receive_negotiate(tlscreds, hostname ? hostname : "<null>"); rc = -EINVAL; if (outioc) { *outioc = NULL; } if (tlscreds && !outioc) { error_setg(errp, "Output I/O channel required for TLS"); goto fail; } if (nbd_read(ioc, buf, 8, errp) < 0) { error_prepend(errp, "Failed to read data"); goto fail; } buf[8] = '\0'; if (strlen(buf) == 0) { error_setg(errp, "Server connection closed unexpectedly"); goto fail; } magic = ldq_be_p(buf); trace_nbd_receive_negotiate_magic(magic); if (memcmp(buf, "NBDMAGIC", 8) != 0) { error_setg(errp, "Invalid magic received"); goto fail; } if (nbd_read(ioc, &magic, sizeof(magic), errp) < 0) { error_prepend(errp, "Failed to read magic"); goto fail; } magic = be64_to_cpu(magic); trace_nbd_receive_negotiate_magic(magic); if (magic == NBD_OPTS_MAGIC) { uint32_t clientflags = 0; uint16_t globalflags; bool fixedNewStyle = false; if (nbd_read(ioc, &globalflags, sizeof(globalflags), errp) < 0) { error_prepend(errp, "Failed to read server flags"); goto fail; } globalflags = be16_to_cpu(globalflags); trace_nbd_receive_negotiate_server_flags(globalflags); if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) { fixedNewStyle = true; clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE; } if (globalflags & NBD_FLAG_NO_ZEROES) { zeroes = false; clientflags |= NBD_FLAG_C_NO_ZEROES; } /* client requested flags */ clientflags = cpu_to_be32(clientflags); if (nbd_write(ioc, &clientflags, sizeof(clientflags), errp) < 0) { error_prepend(errp, "Failed to send clientflags field"); goto fail; } if (tlscreds) { if (fixedNewStyle) { *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp); if (!*outioc) { goto fail; } ioc = *outioc; } else { error_setg(errp, "Server does not support STARTTLS"); goto fail; } } if (!name) { trace_nbd_receive_negotiate_default_name(); name = ""; } if (fixedNewStyle) { int result; if (structured_reply) { result = nbd_request_simple_option(ioc, NBD_OPT_STRUCTURED_REPLY, errp); if (result < 0) { goto fail; } info->structured_reply = result == 1; } /* Try NBD_OPT_GO first - if it works, we are done (it * also gives us a good message if the server requires * TLS). If it is not available, fall back to * NBD_OPT_LIST for nicer error messages about a missing * export, then use NBD_OPT_EXPORT_NAME. */ result = nbd_opt_go(ioc, name, info, errp); if (result < 0) { goto fail; } if (result > 0) { return 0; } /* Check our desired export is present in the * server export list. Since NBD_OPT_EXPORT_NAME * cannot return an error message, running this * query gives us better error reporting if the * export name is not available. */ if (nbd_receive_query_exports(ioc, name, errp) < 0) { goto fail; } } /* write the export name request */ if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, name, errp) < 0) { goto fail; } /* Read the response */ if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) { error_prepend(errp, "Failed to read export length"); goto fail; } be64_to_cpus(&info->size); if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) { error_prepend(errp, "Failed to read export flags"); goto fail; } be16_to_cpus(&info->flags); } else if (magic == NBD_CLIENT_MAGIC) { uint32_t oldflags; if (name) { error_setg(errp, "Server does not support export names"); goto fail; } if (tlscreds) { error_setg(errp, "Server does not support STARTTLS"); goto fail; } if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) { error_prepend(errp, "Failed to read export length"); goto fail; } be64_to_cpus(&info->size); if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) { error_prepend(errp, "Failed to read export flags"); goto fail; } be32_to_cpus(&oldflags); if (oldflags & ~0xffff) { error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags); goto fail; } info->flags = oldflags; } else { error_setg(errp, "Bad magic received"); goto fail; } trace_nbd_receive_negotiate_size_flags(info->size, info->flags); if (zeroes && nbd_drop(ioc, 124, errp) < 0) { error_prepend(errp, "Failed to read reserved block"); goto fail; } rc = 0; fail: return rc; }
int nbd_receive_negotiate(QIOChannel *ioc, const char *name, QCryptoTLSCreds *tlscreds, const char *hostname, QIOChannel **outioc, NBDExportInfo *info, Error **errp) { char buf[256]; uint64_t magic; int rc; bool zeroes = true; trace_nbd_receive_negotiate(tlscreds, hostname ? hostname : "<null>"); rc = -EINVAL; if (outioc) { *outioc = NULL; } if (tlscreds && !outioc) { error_setg(errp, "Output I/O channel required for TLS"); goto fail; } if (nbd_read(ioc, buf, 8, errp) < 0) { error_prepend(errp, "Failed to read data"); goto fail; } buf[8] = '\0'; if (strlen(buf) == 0) { error_setg(errp, "Server connection closed unexpectedly"); goto fail; } magic = ldq_be_p(buf); trace_nbd_receive_negotiate_magic(magic); if (memcmp(buf, "NBDMAGIC", 8) != 0) { error_setg(errp, "Invalid magic received"); goto fail; } if (nbd_read(ioc, &magic, sizeof(magic), errp) < 0) { error_prepend(errp, "Failed to read magic"); goto fail; } magic = be64_to_cpu(magic); trace_nbd_receive_negotiate_magic(magic); if (magic == NBD_OPTS_MAGIC) { uint32_t clientflags = 0; uint16_t globalflags; bool fixedNewStyle = false; if (nbd_read(ioc, &globalflags, sizeof(globalflags), errp) < 0) { error_prepend(errp, "Failed to read server flags"); goto fail; } globalflags = be16_to_cpu(globalflags); trace_nbd_receive_negotiate_server_flags(globalflags); if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) { fixedNewStyle = true; clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE; } if (globalflags & NBD_FLAG_NO_ZEROES) { zeroes = false; clientflags |= NBD_FLAG_C_NO_ZEROES; }   clientflags = cpu_to_be32(clientflags); if (nbd_write(ioc, &clientflags, sizeof(clientflags), errp) < 0) { error_prepend(errp, "Failed to send clientflags field"); goto fail; } if (tlscreds) { if (fixedNewStyle) { *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp); if (!*outioc) { goto fail; } ioc = *outioc; } else { error_setg(errp, "Server does not support STARTTLS"); goto fail; } } if (!name) { trace_nbd_receive_negotiate_default_name(); name = ""; } if (fixedNewStyle) { int result; if (structured_reply) { result = nbd_request_simple_option(ioc, NBD_OPT_STRUCTURED_REPLY, errp); if (result < 0) { goto fail; } info->structured_reply = result == 1; }   result = nbd_opt_go(ioc, name, info, errp); if (result < 0) { goto fail; } if (result > 0) { return 0; }   if (nbd_receive_query_exports(ioc, name, errp) < 0) { goto fail; } }   if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, name, errp) < 0) { goto fail; }   if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) { error_prepend(errp, "Failed to read export length"); goto fail; } be64_to_cpus(&info->size); if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) { error_prepend(errp, "Failed to read export flags"); goto fail; } be16_to_cpus(&info->flags); } else if (magic == NBD_CLIENT_MAGIC) { uint32_t oldflags; if (name) { error_setg(errp, "Server does not support export names"); goto fail; } if (tlscreds) { error_setg(errp, "Server does not support STARTTLS"); goto fail; } if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) { error_prepend(errp, "Failed to read export length"); goto fail; } be64_to_cpus(&info->size); if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) { error_prepend(errp, "Failed to read export flags"); goto fail; } be32_to_cpus(&oldflags); if (oldflags & ~0xffff) { error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags); goto fail; } info->flags = oldflags; } else { error_setg(errp, "Bad magic received"); goto fail; } trace_nbd_receive_negotiate_size_flags(info->size, info->flags); if (zeroes && nbd_drop(ioc, 124, errp) < 0) { error_prepend(errp, "Failed to read reserved block"); goto fail; } rc = 0; fail: return rc; }