/* * SMB1 (CIFS) version specific operations * * Copyright (c) 2012, Jeff Layton <jlayton@redhat.com> * * This library is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License v2 as published * by the Free Software Foundation. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See * the GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "cifsglob.h" #include "cifsproto.h" #include "cifs_debug.h" #include "cifspdu.h" /* * An NT cancel request header looks just like the original request except: * * The Command is SMB_COM_NT_CANCEL * The WordCount is zeroed out * The ByteCount is zeroed out * * This function mangles an existing request buffer into a * SMB_COM_NT_CANCEL request and then sends it. */ static int send_nt_cancel(struct TCP_Server_Info *server, void *buf, struct mid_q_entry *mid) { int rc = 0; struct smb_hdr *in_buf = (struct smb_hdr *)buf; /* -4 for RFC1001 length and +2 for BCC field */ in_buf->smb_buf_length = cpu_to_be32(sizeof(struct smb_hdr) - 4 + 2); in_buf->Command = SMB_COM_NT_CANCEL; in_buf->WordCount = 0; put_bcc(0, in_buf); mutex_lock(&server->srv_mutex); rc = cifs_sign_smb(in_buf, server, &mid->sequence_number); if (rc) { mutex_unlock(&server->srv_mutex); return rc; } rc = smb_send(server, in_buf, be32_to_cpu(in_buf->smb_buf_length)); mutex_unlock(&server->srv_mutex); cFYI(1, "issued NT_CANCEL for mid %u, rc = %d", in_buf->Mid, rc); return rc; } static bool cifs_compare_fids(struct cifsFileInfo *ob1, struct cifsFileInfo *ob2) { return ob1->netfid == ob2->netfid; } static unsigned int cifs_read_data_offset(char *buf) { READ_RSP *rsp = (READ_RSP *)buf; return le16_to_cpu(rsp->DataOffset); } static unsigned int cifs_read_data_length(char *buf) { READ_RSP *rsp = (READ_RSP *)buf; return (le16_to_cpu(rsp->DataLengthHigh) << 16) + le16_to_cpu(rsp->DataLength); } static struct mid_q_entry * cifs_find_mid(struct TCP_Server_Info *server, char *buffer) { struct smb_hdr *buf = (struct smb_hdr *)buffer; struct mid_q_entry *mid; spin_lock(&GlobalMid_Lock); list_for_each_entry(mid, &server->pending_mid_q, qhead) { if (mid->mid == buf->Mid && mid->mid_state == MID_REQUEST_SUBMITTED && le16_to_cpu(mid->command) == buf->Command) { spin_unlock(&GlobalMid_Lock); return mid; } } spin_unlock(&GlobalMid_Lock); return NULL; } static void cifs_add_credits(struct TCP_Server_Info *server, const unsigned int add) { spin_lock(&server->req_lock); server->credits += add; server->in_flight--; spin_unlock(&server->req_lock); wake_up(&server->request_q); } static void cifs_set_credits(struct TCP_Server_Info *server, const int val) { spin_lock(&server->req_lock); server->credits = val; server->oplocks = val > 1 ? enable_oplocks : false; spin_unlock(&server->req_lock); } static int * cifs_get_credits_field(struct TCP_Server_Info *server) { return &server->credits; } /* * Find a free multiplex id (SMB mid). Otherwise there could be * mid collisions which might cause problems, demultiplexing the * wrong response to this request. Multiplex ids could collide if * one of a series requests takes much longer than the others, or * if a very large number of long lived requests (byte range * locks or FindNotify requests) are pending. No more than * 64K-1 requests can be outstanding at one time. If no * mids are available, return zero. A future optimization * could make the combination of mids and uid the key we use * to demultiplex on (rather than mid alone). * In addition to the above check, the cifs demultiplex * code already used the command code as a secondary * check of the frame and if signing is negotiated the * response would be discarded if the mid were the same * but the signature was wrong. Since the mid is not put in the * pending queue until later (when it is about to be dispatched) * we do have to limit the number of outstanding requests * to somewhat less than 64K-1 although it is hard to imagine * so many threads being in the vfs at one time. */ static __u64 cifs_get_next_mid(struct TCP_Server_Info *server) { __u64 mid = 0; __u16 last_mid, cur_mid; bool collision; spin_lock(&GlobalMid_Lock); /* mid is 16 bit only for CIFS/SMB */ cur_mid = (__u16)((server->CurrentMid) & 0xffff); /* we do not want to loop forever */ last_mid = cur_mid; cur_mid++; /* * This nested loop looks more expensive than it is. * In practice the list of pending requests is short, * fewer than 50, and the mids are likely to be unique * on the first pass through the loop unless some request * takes longer than the 64 thousand requests before it * (and it would also have to have been a request that * did not time out). */ while (cur_mid != last_mid) { struct mid_q_entry *mid_entry; unsigned int num_mids; collision = false; if (cur_mid == 0) cur_mid++; num_mids = 0; list_for_each_entry(mid_entry, &server->pending_mid_q, qhead) { ++num_mids; if (mid_entry->mid == cur_mid && mid_entry->mid_state == MID_REQUEST_SUBMITTED) { /* This mid is in use, try a different one */ collision = true; break; } } /* * if we have more than 32k mids in the list, then something * is very wrong. Possibly a local user is trying to DoS the * box by issuing long-running calls and SIGKILL'ing them. If * we get to 2^16 mids then we're in big trouble as this * function could loop forever. * * Go ahead and assign out the mid in this situation, but force * an eventual reconnect to clean out the pending_mid_q. */ if (num_mids > 32768) server->tcpStatus = CifsNeedReconnect; if (!collision) { mid = (__u64)cur_mid; server->CurrentMid = mid; break; } cur_mid++; } spin_unlock(&GlobalMid_Lock); return mid; } struct smb_version_operations smb1_operations = { .send_cancel = send_nt_cancel, .compare_fids = cifs_compare_fids, .setup_request = cifs_setup_request, .check_receive = cifs_check_receive, .add_credits = cifs_add_credits, .set_credits = cifs_set_credits, .get_credits_field = cifs_get_credits_field, .get_next_mid = cifs_get_next_mid, .read_data_offset = cifs_read_data_offset, .read_data_length = cifs_read_data_length, .map_error = map_smb_to_linux_error, .find_mid = cifs_find_mid, .check_message = checkSMB, .dump_detail = cifs_dump_detail, .is_oplock_break = is_valid_oplock_break, }; struct smb_version_values smb1_values = { .version_string = SMB1_VERSION_STRING, .large_lock_type = LOCKING_ANDX_LARGE_FILES, .exclusive_lock_type = 0, .shared_lock_type = LOCKING_ANDX_SHARED_LOCK, .unlock_lock_type = 0, .header_size = sizeof(struct smb_hdr), .max_header_size = MAX_CIFS_HDR_SIZE, .read_rsp_size = sizeof(READ_RSP), };