--- src/connections.c | 234 +++++++++++++++++++++++++++++++++++++--------- src/protocol.h | 11 +++ 2 files changed, 201 insertions(+), 44 deletions(-) diff --git a/src/connections.c b/src/connections.c index ba6e91d..5f09984 100644 --- a/src/connections.c +++ b/src/connections.c @@ -75,7 +75,9 @@ struct connection { void **handles; size_t nr_handles; + uint32_t cflags; uint64_t exportsize; + uint16_t eflags; int readonly; int can_flush; int is_rotational; @@ -572,6 +574,55 @@ send_newstyle_option_reply_exportname (struct connection *conn, return 0; } +static int +send_newstyle_option_reply_info_export (struct connection *conn, + uint32_t option, uint32_t reply, + uint16_t info) +{ + struct fixed_new_option_reply fixed_new_option_reply; + struct fixed_new_option_reply_info_export export; + + fixed_new_option_reply.magic = htobe64 (NBD_REP_MAGIC); + fixed_new_option_reply.option = htobe32 (option); + fixed_new_option_reply.reply = htobe32 (reply); + fixed_new_option_reply.replylen = htobe32 (sizeof export); + export.info = htobe16 (info); + export.exportsize = htobe64 (conn->exportsize); + export.eflags = htobe16 (conn->eflags); + + if (conn->send (conn, + &fixed_new_option_reply, + sizeof fixed_new_option_reply) == -1 || + conn->send (conn, &export, sizeof export) == -1) { + nbdkit_error ("write: %m"); + return -1; + } + + return 0; +} + +static int +get_size_and_eflags (struct connection *conn) +{ + int64_t r; + + r = backend->get_size (backend, conn); + if (r == -1) + return -1; + if (r < 0) { + nbdkit_error (".get_size function returned invalid value " + "(%" PRIi64 ")", r); + return -1; + } + conn->exportsize = (uint64_t) r; + + if (compute_eflags (conn, &conn->eflags) < 0) + return -1; + + debug ("newstyle negotiation: flags: export 0x%x", conn->eflags); + return 0; +} + static int _negotiate_handshake_newstyle_options (struct connection *conn) { @@ -581,6 +632,7 @@ _negotiate_handshake_newstyle_options (struct connection *conn) uint32_t option; uint32_t optlen; char data[MAX_OPTION_LENGTH+1]; + struct new_handshake_finish handshake_finish; for (nr_options = 0; nr_options < MAX_NR_OPTIONS; ++nr_options) { if (conn->recv (conn, &new_option, sizeof new_option) == -1) { @@ -625,7 +677,8 @@ _negotiate_handshake_newstyle_options (struct connection *conn) } /* Apart from printing it, ignore the export name. */ data[optlen] = '\0'; - debug ("newstyle negotiation: client requested export '%s' (ignored)", + debug ("newstyle negotiation: NBD_OPT_EXPORT_NAME: " + "client requested export '%s' (ignored)", data); break; @@ -701,6 +754,100 @@ _negotiate_handshake_newstyle_options (struct connection *conn) } break; + case NBD_OPT_GO: + if (conn->recv (conn, data, optlen) == -1) { + nbdkit_error ("read: %m"); + return -1; + } + + if (optlen < 6) { /* 32 bit export length + 16 bit nr info */ + debug ("newstyle negotiation: NBD_OPT_GO option length < 6"); + + if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID) + == -1) + return -1; + continue; + } + + { + uint32_t exportnamelen; + uint16_t nrinfos; + uint16_t info; + size_t i; + CLEANUP_FREE char *requested_exportname = NULL; + + /* Validate the name length and number of INFO requests. */ + memcpy (&exportnamelen, &data[0], 4); + exportnamelen = be32toh (exportnamelen); + if (exportnamelen+6 > optlen) { + debug ("newstyle negotiation: NBD_OPT_GO: export name too long"); + if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID) + == -1) + return -1; + continue; + } + memcpy (&nrinfos, &data[exportnamelen+4], 2); + nrinfos = be16toh (nrinfos); + if (optlen != 4 + exportnamelen + 2 + 2*nrinfos) { + debug ("newstyle negotiation: NBD_OPT_GO: number of information requests incorrect"); + if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID) + == -1) + return -1; + continue; + } + + /* As with NBD_OPT_EXPORT_NAME we print the export name and then + * ignore it. + */ + requested_exportname = malloc (exportnamelen+1); + if (requested_exportname == NULL) { + nbdkit_error ("malloc: %m"); + return -1; + } + memcpy (requested_exportname, &data[4], exportnamelen); + requested_exportname[exportnamelen] = '\0'; + debug ("newstyle negotiation: NBD_OPT_GO: " + "client requested export '%s' (ignored)", + requested_exportname); + + /* The spec is confusing, but it is required that we send back + * NBD_INFO_EXPORT, even if the client did not request it! + * qemu client in particular does not request this, but will + * fail if we don't send it. + */ + if (get_size_and_eflags (conn) == -1) + return -1; + if (send_newstyle_option_reply_info_export (conn, option, + NBD_REP_INFO, + NBD_INFO_EXPORT) == -1) + return -1; + + /* For now we ignore all other info requests (but we must + * ignore NBD_INFO_EXPORT if it was requested, because we + * replied already above). Therefore this loop doesn't do + * much at the moment. + */ + for (i = 0; i < nrinfos; ++i) { + memcpy (&info, &data[4+exportnamelen+2+i*2], 2); + info = be16toh (info); + switch (info) { + case NBD_INFO_EXPORT: /* ignore - reply sent above */ break; + default: + debug ("newstyle negotiation: NBD_OPT_GO: " + "ignoring NBD_INFO_* request %u", (unsigned) info); + break; + } + } + } + + /* Unlike NBD_OPT_EXPORT_NAME, NBD_OPT_GO sends back an ACK + * or ERROR packet. + */ + if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1) + return -1; + + break; + default: /* Unknown option. */ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_UNSUP) == -1) @@ -712,10 +859,10 @@ _negotiate_handshake_newstyle_options (struct connection *conn) } /* Note, since it's not very clear from the protocol doc, that the - * client must send NBD_OPT_EXPORT_NAME last, and that ends option - * negotiation. + * client must send NBD_OPT_EXPORT_NAME or NBD_OPT_GO last, and + * that ends option negotiation. */ - if (option == NBD_OPT_EXPORT_NAME) + if (option == NBD_OPT_EXPORT_NAME || option == NBD_OPT_GO) break; } @@ -733,6 +880,40 @@ _negotiate_handshake_newstyle_options (struct connection *conn) return -1; } + /* If the last option was NBD_OPT_EXPORT_NAME then we have to + * finish the handshake by sending handshake_finish. + */ + if (option == NBD_OPT_EXPORT_NAME) { + finish: + if (get_size_and_eflags (conn) == -1) + return -1; + + memset (&handshake_finish, 0, sizeof handshake_finish); + handshake_finish.exportsize = htobe64 (conn->exportsize); + handshake_finish.eflags = htobe16 (conn->eflags); + + if (conn->send (conn, + &handshake_finish, + (conn->cflags & NBD_FLAG_NO_ZEROES) + ? offsetof (struct new_handshake_finish, zeroes) + : sizeof handshake_finish) == -1) { + nbdkit_error ("write: %m"); + return -1; + } + } + /* If the last option was NBD_OPT_GO then we're all done. */ + else if (option == NBD_OPT_GO) + ; + /* Else the client didn't end the list of options properly. This + * may be a buggy client, but nbdkit has always continued + * regardless. However emit a debug message. + */ + else { + debug ("warning: client options list didn't finish with NBD_OPT_GO " + "or NBD_OPT_EXPORT_NAME"); + goto finish; + } + return 0; } @@ -741,11 +922,6 @@ _negotiate_handshake_newstyle (struct connection *conn) { struct new_handshake handshake; uint16_t gflags; - uint32_t cflags; - struct new_handshake_finish handshake_finish; - int64_t r; - uint64_t exportsize; - uint16_t eflags; gflags = NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES; @@ -761,15 +937,15 @@ _negotiate_handshake_newstyle (struct connection *conn) } /* Client now sends us its 32 bit flags word ... */ - if (conn->recv (conn, &cflags, sizeof cflags) == -1) { + if (conn->recv (conn, &conn->cflags, 4) == -1) { nbdkit_error ("read: %m"); return -1; } - cflags = be32toh (cflags); + conn->cflags = be32toh (conn->cflags); /* ... which we check for accuracy. */ - debug ("newstyle negotiation: client flags: 0x%x", cflags); - if (cflags & ~gflags) { - nbdkit_error ("client requested unknown flags 0x%x", cflags); + debug ("newstyle negotiation: client flags: 0x%x", conn->cflags); + if (conn->cflags & ~gflags) { + nbdkit_error ("client requested unknown flags 0x%x", conn->cflags); return -1; } @@ -777,36 +953,6 @@ _negotiate_handshake_newstyle (struct connection *conn) if (_negotiate_handshake_newstyle_options (conn) == -1) return -1; - /* Finish the newstyle handshake. */ - r = backend->get_size (backend, conn); - if (r == -1) - return -1; - if (r < 0) { - nbdkit_error (".get_size function returned invalid value " - "(%" PRIi64 ")", r); - return -1; - } - exportsize = (uint64_t) r; - conn->exportsize = exportsize; - - if (compute_eflags (conn, &eflags) < 0) - return -1; - - debug ("newstyle negotiation: flags: export 0x%x", eflags); - - memset (&handshake_finish, 0, sizeof handshake_finish); - handshake_finish.exportsize = htobe64 (exportsize); - handshake_finish.eflags = htobe16 (eflags); - - if (conn->send (conn, - &handshake_finish, - (cflags & NBD_FLAG_NO_ZEROES) - ? offsetof (struct new_handshake_finish, zeroes) - : sizeof handshake_finish) == -1) { - nbdkit_error ("write: %m"); - return -1; - } - return 0; } diff --git a/src/protocol.h b/src/protocol.h index aa458a0..c02e164 100644 --- a/src/protocol.h +++ b/src/protocol.h @@ -100,15 +100,26 @@ struct new_handshake_finish { #define NBD_OPT_ABORT 2 #define NBD_OPT_LIST 3 #define NBD_OPT_STARTTLS 5 +#define NBD_OPT_GO 7 #define NBD_REP_ACK 1 #define NBD_REP_SERVER 2 +#define NBD_REP_INFO 3 #define NBD_REP_ERR_UNSUP 0x80000001 #define NBD_REP_ERR_POLICY 0x80000002 #define NBD_REP_ERR_INVALID 0x80000003 #define NBD_REP_ERR_PLATFORM 0x80000004 #define NBD_REP_ERR_TLS_REQD 0x80000005 +#define NBD_INFO_EXPORT 0 + +/* NBD_INFO_EXPORT reply (follows fixed_new_option_reply). */ +struct fixed_new_option_reply_info_export { + uint16_t info; /* NBD_INFO_EXPORT */ + uint64_t exportsize; /* size of export */ + uint16_t eflags; /* per-export flags */ +} __attribute__((packed)); + /* Request (client -> server). */ struct request { uint32_t magic; /* NBD_REQUEST_MAGIC. */ -- 2.18.0