Re: [Libguestfs] [PATCH nbdkit v2] protocol: Implement NBD_OPT_GO.

--- src/connections.c | 233 +++++++++++++++++++++++++++++++++++++--------- src/protocol.h | 27 ++++-- 2 files changed, 209 insertions(+), 51 deletions(-)

@@ -701,6 +754,101 @@ _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 > optlen-6 /* NB optlen >= 6, see above */) {

+ 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 +860,10 @@ _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 +881,38 @@ _negotiate_handshake_newstyle_options (struct connection *conn) return -1; } + /* If the last option was NBD_OPT_GO then we're all done. */ + if (option == NBD_OPT_GO) + ; + /* Else if the last option was NBD_OPT_EXPORT_NAME then we have to + * finish the handshake by sending handshake_finish. + */ + else if (option == NBD_OPT_EXPORT_NAME) { + 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; + } + } + /* The client is buggy. The last option must be NBD_OPT_GO or + * NBD_OPT_EXPORT_NAME. + */ + else {

+ nbdkit_error ("client options list didn't finish with NBD_OPT_GO " + "or NBD_OPT_EXPORT_NAME"); + return -1;

+ } + return 0; } @@ -741,11 +921,6 @@ _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 +936,15 @@ _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) {