Message ID | 1460153158-21612-16-git-send-email-eblake@redhat.com |
---|---|
State | New |
Headers | show |
On 8 Apr 2016, at 23:05, Eric Blake <eblake@redhat.com> wrote: > NBD_OPT_EXPORT_NAME is lousy: it requires us to close the connection > rather than report an error. Upstream NBD recently added NBD_OPT_GO > as the improved version of the option that does what we want, along > with NBD_OPT_INFO that returns the same information but does not > transition to transmission phase. > > Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alex Bligh <alex@alex.org.uk> > --- > nbd/server.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 109 insertions(+), 13 deletions(-) > > diff --git a/nbd/server.c b/nbd/server.c > index 379df8c..e68e83c 100644 > --- a/nbd/server.c > +++ b/nbd/server.c > @@ -233,17 +233,19 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt) > return nbd_negotiate_send_rep_len(ioc, type, opt, 0); > } > > -/* Send an NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. > +/* Send the common part of an NBD_REP_SERVER reply for the given option, > + * and include extra_len in the advertised payload. > * Return -errno to kill connection, 0 to continue negotiation */ > -static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) > +static int nbd_negotiate_send_rep_server(QIOChannel *ioc, NBDExport *exp, > + uint32_t opt, uint32_t extra_len) > { > uint32_t len; > int rc; > > TRACE("Advertising export name '%s'", exp->name ? exp->name : ""); > len = strlen(exp->name); > - rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, > - len + sizeof(len)); > + rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, opt, > + len + sizeof(len) + extra_len); > if (rc < 0) { > return rc; > } > @@ -261,6 +263,15 @@ static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) > return 0; > } > > +/* Send an NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. > + * Return -errno to kill connection, 0 to continue negotiation. */ > +static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) > +{ > + return nbd_negotiate_send_rep_server(ioc, exp, NBD_OPT_LIST, 0); > +} > + > +/* Send a sequence of replies to NBD_OPT_LIST. > + * Return -errno to kill connection, 0 to continue negotiation. */ > static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length) > { > NBDExport *exp; > @@ -283,6 +294,8 @@ static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length) > return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST); > } > > +/* Send a reply to NBD_OPT_EXPORT_NAME. > + * Return -errno to kill connection, 0 to end negotiation. */ > static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length) > { > int rc = -EINVAL; > @@ -318,6 +331,73 @@ fail: > } > > > +/* Handle NBD_OPT_INFO and NBD_OPT_GO. > + * Return -errno to kill connection, 0 if ready for next option, and 1 > + * to move into transmission phase. */ > +static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length, > + uint32_t opt, uint16_t myflags) > +{ > + int rc; > + char name[NBD_MAX_NAME_SIZE + 1]; > + NBDExport *exp; > + uint64_t size; > + uint16_t flags; > + > + /* Client sends: > + [20 .. xx] export name (length bytes) > + */ > + TRACE("Checking length"); > + if (length >= sizeof(name)) { > + if (nbd_negotiate_drop_sync(client->ioc, length) != length) { > + return -EIO; > + } > + return nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_INVALID, opt); > + } > + if (nbd_negotiate_read(client->ioc, name, length) != length) { > + LOG("read failed"); > + return -EIO; > + } > + name[length] = '\0'; > + > + TRACE("Client requested info on export '%s'", name); > + > + exp = nbd_export_find(name); > + if (!exp) { > + return nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNKNOWN, opt); > + } > + > + QEMU_BUILD_BUG_ON(NBD_FINAL_REPLY_SIZE != sizeof(size) + sizeof(flags)); > + rc = nbd_negotiate_send_rep_server(client->ioc, exp, opt, > + NBD_FINAL_REPLY_SIZE); > + if (rc < 0) { > + return rc; > + } > + > + assert((exp->nbdflags & ~65535) == 0); > + size = cpu_to_be64(exp->size); > + flags = cpu_to_be16(exp->nbdflags | myflags); > + > + if (nbd_negotiate_write(client->ioc, &size, sizeof(size)) != > + sizeof(size)) { > + LOG("write failed"); > + return -EIO; > + } > + if (nbd_negotiate_write(client->ioc, &flags, sizeof(flags)) != > + sizeof(flags)) { > + LOG("write failed"); > + return -EIO; > + } > + > + if (opt == NBD_OPT_GO) { > + client->exp = exp; > + QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); > + nbd_export_get(client->exp); > + rc = 1; > + } > + return rc; > +} > + > + > static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, > uint32_t length) > { > @@ -366,7 +446,10 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, > } > > > -static int nbd_negotiate_options(NBDClient *client) > +/* Loop over all client options, during fixed newstyle negotiation. > + * Return -errno to kill connection, 0 on successful NBD_OPT_EXPORT_NAME, > + * 1 on successful NBD_OPT_GO. */ > +static int nbd_negotiate_options(NBDClient *client, uint16_t myflags) > { > uint32_t flags; > bool fixedNewstyle = false; > @@ -480,6 +563,16 @@ static int nbd_negotiate_options(NBDClient *client) > case NBD_OPT_EXPORT_NAME: > return nbd_negotiate_handle_export_name(client, length); > > + case NBD_OPT_INFO: > + case NBD_OPT_GO: > + ret = nbd_negotiate_handle_info(client, length, clientflags, > + myflags); > + if (ret) { > + assert(ret < 0 || clientflags == NBD_OPT_GO); > + return ret; > + } > + break; > + > case NBD_OPT_STARTTLS: > if (nbd_negotiate_drop_sync(client->ioc, length) != length) { > return -EIO; > @@ -584,18 +677,21 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data) > LOG("write failed"); > goto fail; > } > - rc = nbd_negotiate_options(client); > - if (rc != 0) { > + rc = nbd_negotiate_options(client, myflags); > + if (rc < 0) { > LOG("option negotiation failed"); > goto fail; > } > > - stq_be_p(buf + 18, client->exp->size); > - stw_be_p(buf + 26, client->exp->nbdflags | myflags); > - len = client->no_zeroes ? 10 : sizeof(buf) - 18; > - if (nbd_negotiate_write(client->ioc, buf + 18, len) != len) { > - LOG("write failed"); > - goto fail; > + if (!rc) { > + /* If options ended with NBD_OPT_GO, we already sent this. */ > + stq_be_p(buf + 18, client->exp->size); > + stw_be_p(buf + 26, client->exp->nbdflags | myflags); > + len = client->no_zeroes ? 10 : sizeof(buf) - 18; > + if (nbd_negotiate_write(client->ioc, buf + 18, len) != len) { > + LOG("write failed"); > + goto fail; > + } > } > } > > -- > 2.5.5 > >
diff --git a/nbd/server.c b/nbd/server.c index 379df8c..e68e83c 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -233,17 +233,19 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt) return nbd_negotiate_send_rep_len(ioc, type, opt, 0); } -/* Send an NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. +/* Send the common part of an NBD_REP_SERVER reply for the given option, + * and include extra_len in the advertised payload. * Return -errno to kill connection, 0 to continue negotiation */ -static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) +static int nbd_negotiate_send_rep_server(QIOChannel *ioc, NBDExport *exp, + uint32_t opt, uint32_t extra_len) { uint32_t len; int rc; TRACE("Advertising export name '%s'", exp->name ? exp->name : ""); len = strlen(exp->name); - rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, - len + sizeof(len)); + rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, opt, + len + sizeof(len) + extra_len); if (rc < 0) { return rc; } @@ -261,6 +263,15 @@ static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) return 0; } +/* Send an NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. + * Return -errno to kill connection, 0 to continue negotiation. */ +static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) +{ + return nbd_negotiate_send_rep_server(ioc, exp, NBD_OPT_LIST, 0); +} + +/* Send a sequence of replies to NBD_OPT_LIST. + * Return -errno to kill connection, 0 to continue negotiation. */ static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length) { NBDExport *exp; @@ -283,6 +294,8 @@ static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length) return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST); } +/* Send a reply to NBD_OPT_EXPORT_NAME. + * Return -errno to kill connection, 0 to end negotiation. */ static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length) { int rc = -EINVAL; @@ -318,6 +331,73 @@ fail: } +/* Handle NBD_OPT_INFO and NBD_OPT_GO. + * Return -errno to kill connection, 0 if ready for next option, and 1 + * to move into transmission phase. */ +static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length, + uint32_t opt, uint16_t myflags) +{ + int rc; + char name[NBD_MAX_NAME_SIZE + 1]; + NBDExport *exp; + uint64_t size; + uint16_t flags; + + /* Client sends: + [20 .. xx] export name (length bytes) + */ + TRACE("Checking length"); + if (length >= sizeof(name)) { + if (nbd_negotiate_drop_sync(client->ioc, length) != length) { + return -EIO; + } + return nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_INVALID, opt); + } + if (nbd_negotiate_read(client->ioc, name, length) != length) { + LOG("read failed"); + return -EIO; + } + name[length] = '\0'; + + TRACE("Client requested info on export '%s'", name); + + exp = nbd_export_find(name); + if (!exp) { + return nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNKNOWN, opt); + } + + QEMU_BUILD_BUG_ON(NBD_FINAL_REPLY_SIZE != sizeof(size) + sizeof(flags)); + rc = nbd_negotiate_send_rep_server(client->ioc, exp, opt, + NBD_FINAL_REPLY_SIZE); + if (rc < 0) { + return rc; + } + + assert((exp->nbdflags & ~65535) == 0); + size = cpu_to_be64(exp->size); + flags = cpu_to_be16(exp->nbdflags | myflags); + + if (nbd_negotiate_write(client->ioc, &size, sizeof(size)) != + sizeof(size)) { + LOG("write failed"); + return -EIO; + } + if (nbd_negotiate_write(client->ioc, &flags, sizeof(flags)) != + sizeof(flags)) { + LOG("write failed"); + return -EIO; + } + + if (opt == NBD_OPT_GO) { + client->exp = exp; + QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); + nbd_export_get(client->exp); + rc = 1; + } + return rc; +} + + static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, uint32_t length) { @@ -366,7 +446,10 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, } -static int nbd_negotiate_options(NBDClient *client) +/* Loop over all client options, during fixed newstyle negotiation. + * Return -errno to kill connection, 0 on successful NBD_OPT_EXPORT_NAME, + * 1 on successful NBD_OPT_GO. */ +static int nbd_negotiate_options(NBDClient *client, uint16_t myflags) { uint32_t flags; bool fixedNewstyle = false; @@ -480,6 +563,16 @@ static int nbd_negotiate_options(NBDClient *client) case NBD_OPT_EXPORT_NAME: return nbd_negotiate_handle_export_name(client, length); + case NBD_OPT_INFO: + case NBD_OPT_GO: + ret = nbd_negotiate_handle_info(client, length, clientflags, + myflags); + if (ret) { + assert(ret < 0 || clientflags == NBD_OPT_GO); + return ret; + } + break; + case NBD_OPT_STARTTLS: if (nbd_negotiate_drop_sync(client->ioc, length) != length) { return -EIO; @@ -584,18 +677,21 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data) LOG("write failed"); goto fail; } - rc = nbd_negotiate_options(client); - if (rc != 0) { + rc = nbd_negotiate_options(client, myflags); + if (rc < 0) { LOG("option negotiation failed"); goto fail; } - stq_be_p(buf + 18, client->exp->size); - stw_be_p(buf + 26, client->exp->nbdflags | myflags); - len = client->no_zeroes ? 10 : sizeof(buf) - 18; - if (nbd_negotiate_write(client->ioc, buf + 18, len) != len) { - LOG("write failed"); - goto fail; + if (!rc) { + /* If options ended with NBD_OPT_GO, we already sent this. */ + stq_be_p(buf + 18, client->exp->size); + stw_be_p(buf + 26, client->exp->nbdflags | myflags); + len = client->no_zeroes ? 10 : sizeof(buf) - 18; + if (nbd_negotiate_write(client->ioc, buf + 18, len) != len) { + LOG("write failed"); + goto fail; + } } }
NBD_OPT_EXPORT_NAME is lousy: it requires us to close the connection rather than report an error. Upstream NBD recently added NBD_OPT_GO as the improved version of the option that does what we want, along with NBD_OPT_INFO that returns the same information but does not transition to transmission phase. Signed-off-by: Eric Blake <eblake@redhat.com> --- nbd/server.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 109 insertions(+), 13 deletions(-)