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connect.c
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// SPDX-License-Identifier: LGPL-2.1
/*
*
* Copyright (C) International Business Machines Corp., 2002,2011
* Author(s): Steve French (sfrench@us.ibm.com)
*
*/
#include <linux/fs.h>
#include <linux/net.h>
#include <linux/string.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/ctype.h>
#include <linux/utsname.h>
#include <linux/mempool.h>
#include <linux/delay.h>
#include <linux/completion.h>
#include <linux/kthread.h>
#include <linux/pagevec.h>
#include <linux/freezer.h>
#include <linux/namei.h>
#include <linux/uuid.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <linux/inet.h>
#include <linux/module.h>
#include <keys/user-type.h>
#include <net/ipv6.h>
#include <linux/parser.h>
#include <linux/bvec.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "ntlmssp.h"
#include "nterr.h"
#include "rfc1002pdu.h"
#include "fscache.h"
#include "smb2proto.h"
#include "smbdirect.h"
#include "dns_resolve.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dfs_cache.h"
#endif
#include "fs_context.h"
#include "cifs_swn.h"
extern mempool_t *cifs_req_poolp;
extern bool disable_legacy_dialects;
/* FIXME: should these be tunable? */
#define TLINK_ERROR_EXPIRE (1 * HZ)
#define TLINK_IDLE_EXPIRE (600 * HZ)
/* Drop the connection to not overload the server */
#define NUM_STATUS_IO_TIMEOUT 5
static int ip_connect(struct TCP_Server_Info *server);
static int generic_ip_connect(struct TCP_Server_Info *server);
static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);
static void cifs_prune_tlinks(struct work_struct *work);
/*
* Resolve hostname and set ip addr in tcp ses. Useful for hostnames that may
* get their ip addresses changed at some point.
*
* This should be called with server->srv_mutex held.
*/
static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
{
int rc;
int len;
char *unc, *ipaddr = NULL;
time64_t expiry, now;
unsigned long ttl = SMB_DNS_RESOLVE_INTERVAL_DEFAULT;
if (!server->hostname)
return -EINVAL;
len = strlen(server->hostname) + 3;
unc = kmalloc(len, GFP_KERNEL);
if (!unc) {
cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);
return -ENOMEM;
}
scnprintf(unc, len, "\\\\%s", server->hostname);
rc = dns_resolve_server_name_to_ip(unc, &ipaddr, &expiry);
kfree(unc);
if (rc < 0) {
cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n",
__func__, server->hostname, rc);
goto requeue_resolve;
}
spin_lock(&cifs_tcp_ses_lock);
rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,
strlen(ipaddr));
spin_unlock(&cifs_tcp_ses_lock);
kfree(ipaddr);
/* rc == 1 means success here */
if (rc) {
now = ktime_get_real_seconds();
if (expiry && expiry > now)
/*
* To make sure we don't use the cached entry, retry 1s
* after expiry.
*/
ttl = (expiry - now + 1);
}
rc = !rc ? -1 : 0;
requeue_resolve:
cifs_dbg(FYI, "%s: next dns resolution scheduled for %lu seconds in the future\n",
__func__, ttl);
mod_delayed_work(cifsiod_wq, &server->resolve, (ttl * HZ));
return rc;
}
static void cifs_resolve_server(struct work_struct *work)
{
int rc;
struct TCP_Server_Info *server = container_of(work,
struct TCP_Server_Info, resolve.work);
mutex_lock(&server->srv_mutex);
/*
* Resolve the hostname again to make sure that IP address is up-to-date.
*/
rc = reconn_set_ipaddr_from_hostname(server);
if (rc) {
cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
__func__, rc);
}
mutex_unlock(&server->srv_mutex);
}
#ifdef CONFIG_CIFS_DFS_UPCALL
/* These functions must be called with server->srv_mutex held */
static void reconn_set_next_dfs_target(struct TCP_Server_Info *server,
struct cifs_sb_info *cifs_sb,
struct dfs_cache_tgt_list *tgt_list,
struct dfs_cache_tgt_iterator **tgt_it)
{
const char *name;
int rc;
if (!cifs_sb || !cifs_sb->origin_fullpath)
return;
if (!*tgt_it) {
*tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
} else {
*tgt_it = dfs_cache_get_next_tgt(tgt_list, *tgt_it);
if (!*tgt_it)
*tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
}
cifs_dbg(FYI, "%s: UNC: %s\n", __func__, cifs_sb->origin_fullpath);
name = dfs_cache_get_tgt_name(*tgt_it);
kfree(server->hostname);
server->hostname = extract_hostname(name);
if (IS_ERR(server->hostname)) {
cifs_dbg(FYI,
"%s: failed to extract hostname from target: %ld\n",
__func__, PTR_ERR(server->hostname));
return;
}
rc = reconn_set_ipaddr_from_hostname(server);
if (rc) {
cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
__func__, rc);
}
}
static inline int reconn_setup_dfs_targets(struct cifs_sb_info *cifs_sb,
struct dfs_cache_tgt_list *tl)
{
if (!cifs_sb->origin_fullpath)
return -EOPNOTSUPP;
return dfs_cache_noreq_find(cifs_sb->origin_fullpath + 1, NULL, tl);
}
#endif
/*
* cifs tcp session reconnection
*
* mark tcp session as reconnecting so temporarily locked
* mark all smb sessions as reconnecting for tcp session
* reconnect tcp session
* wake up waiters on reconnection? - (not needed currently)
*/
int
cifs_reconnect(struct TCP_Server_Info *server)
{
int rc = 0;
struct list_head *tmp, *tmp2;
struct cifs_ses *ses;
struct cifs_tcon *tcon;
struct mid_q_entry *mid_entry;
struct list_head retry_list;
#ifdef CONFIG_CIFS_DFS_UPCALL
struct super_block *sb = NULL;
struct cifs_sb_info *cifs_sb = NULL;
struct dfs_cache_tgt_list tgt_list = DFS_CACHE_TGT_LIST_INIT(tgt_list);
struct dfs_cache_tgt_iterator *tgt_it = NULL;
#endif
spin_lock(&GlobalMid_Lock);
server->nr_targets = 1;
#ifdef CONFIG_CIFS_DFS_UPCALL
spin_unlock(&GlobalMid_Lock);
sb = cifs_get_tcp_super(server);
if (IS_ERR(sb)) {
rc = PTR_ERR(sb);
cifs_dbg(FYI, "%s: will not do DFS failover: rc = %d\n",
__func__, rc);
sb = NULL;
} else {
cifs_sb = CIFS_SB(sb);
rc = reconn_setup_dfs_targets(cifs_sb, &tgt_list);
if (rc) {
cifs_sb = NULL;
if (rc != -EOPNOTSUPP) {
cifs_server_dbg(VFS, "%s: no target servers for DFS failover\n",
__func__);
}
} else {
server->nr_targets = dfs_cache_get_nr_tgts(&tgt_list);
}
}
cifs_dbg(FYI, "%s: will retry %d target(s)\n", __func__,
server->nr_targets);
spin_lock(&GlobalMid_Lock);
#endif
if (server->tcpStatus == CifsExiting) {
/* the demux thread will exit normally
next time through the loop */
spin_unlock(&GlobalMid_Lock);
#ifdef CONFIG_CIFS_DFS_UPCALL
dfs_cache_free_tgts(&tgt_list);
cifs_put_tcp_super(sb);
#endif
wake_up(&server->response_q);
return rc;
} else
server->tcpStatus = CifsNeedReconnect;
spin_unlock(&GlobalMid_Lock);
server->maxBuf = 0;
server->max_read = 0;
cifs_dbg(FYI, "Mark tcp session as need reconnect\n");
trace_smb3_reconnect(server->CurrentMid, server->conn_id, server->hostname);
/* before reconnecting the tcp session, mark the smb session (uid)
and the tid bad so they are not used until reconnected */
cifs_dbg(FYI, "%s: marking sessions and tcons for reconnect\n",
__func__);
spin_lock(&cifs_tcp_ses_lock);
list_for_each(tmp, &server->smb_ses_list) {
ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
ses->need_reconnect = true;
list_for_each(tmp2, &ses->tcon_list) {
tcon = list_entry(tmp2, struct cifs_tcon, tcon_list);
tcon->need_reconnect = true;
}
if (ses->tcon_ipc)
ses->tcon_ipc->need_reconnect = true;
}
spin_unlock(&cifs_tcp_ses_lock);
/* do not want to be sending data on a socket we are freeing */
cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
mutex_lock(&server->srv_mutex);
if (server->ssocket) {
cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n",
server->ssocket->state, server->ssocket->flags);
kernel_sock_shutdown(server->ssocket, SHUT_WR);
cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n",
server->ssocket->state, server->ssocket->flags);
sock_release(server->ssocket);
server->ssocket = NULL;
}
server->sequence_number = 0;
server->session_estab = false;
kfree(server->session_key.response);
server->session_key.response = NULL;
server->session_key.len = 0;
server->lstrp = jiffies;
/* mark submitted MIDs for retry and issue callback */
INIT_LIST_HEAD(&retry_list);
cifs_dbg(FYI, "%s: moving mids to private list\n", __func__);
spin_lock(&GlobalMid_Lock);
list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
kref_get(&mid_entry->refcount);
if (mid_entry->mid_state == MID_REQUEST_SUBMITTED)
mid_entry->mid_state = MID_RETRY_NEEDED;
list_move(&mid_entry->qhead, &retry_list);
mid_entry->mid_flags |= MID_DELETED;
}
spin_unlock(&GlobalMid_Lock);
mutex_unlock(&server->srv_mutex);
cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
list_for_each_safe(tmp, tmp2, &retry_list) {
mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
list_del_init(&mid_entry->qhead);
mid_entry->callback(mid_entry);
cifs_mid_q_entry_release(mid_entry);
}
if (cifs_rdma_enabled(server)) {
mutex_lock(&server->srv_mutex);
smbd_destroy(server);
mutex_unlock(&server->srv_mutex);
}
do {
try_to_freeze();
mutex_lock(&server->srv_mutex);
if (!cifs_swn_set_server_dstaddr(server)) {
#ifdef CONFIG_CIFS_DFS_UPCALL
if (cifs_sb && cifs_sb->origin_fullpath)
/*
* Set up next DFS target server (if any) for reconnect. If DFS
* feature is disabled, then we will retry last server we
* connected to before.
*/
reconn_set_next_dfs_target(server, cifs_sb, &tgt_list, &tgt_it);
else {
#endif
/*
* Resolve the hostname again to make sure that IP address is up-to-date.
*/
rc = reconn_set_ipaddr_from_hostname(server);
if (rc) {
cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
__func__, rc);
}
#ifdef CONFIG_CIFS_DFS_UPCALL
}
#endif
}
if (cifs_rdma_enabled(server))
rc = smbd_reconnect(server);
else
rc = generic_ip_connect(server);
if (rc) {
cifs_dbg(FYI, "reconnect error %d\n", rc);
mutex_unlock(&server->srv_mutex);
msleep(3000);
} else {
atomic_inc(&tcpSesReconnectCount);
set_credits(server, 1);
spin_lock(&GlobalMid_Lock);
if (server->tcpStatus != CifsExiting)
server->tcpStatus = CifsNeedNegotiate;
spin_unlock(&GlobalMid_Lock);
cifs_swn_reset_server_dstaddr(server);
mutex_unlock(&server->srv_mutex);
}
} while (server->tcpStatus == CifsNeedReconnect);
#ifdef CONFIG_CIFS_DFS_UPCALL
if (tgt_it) {
rc = dfs_cache_noreq_update_tgthint(cifs_sb->origin_fullpath + 1,
tgt_it);
if (rc) {
cifs_server_dbg(VFS, "%s: failed to update DFS target hint: rc = %d\n",
__func__, rc);
}
dfs_cache_free_tgts(&tgt_list);
}
cifs_put_tcp_super(sb);
#endif
if (server->tcpStatus == CifsNeedNegotiate)
mod_delayed_work(cifsiod_wq, &server->echo, 0);
wake_up(&server->response_q);
return rc;
}
static void
cifs_echo_request(struct work_struct *work)
{
int rc;
struct TCP_Server_Info *server = container_of(work,
struct TCP_Server_Info, echo.work);
/*
* We cannot send an echo if it is disabled.
* Also, no need to ping if we got a response recently.
*/
if (server->tcpStatus == CifsNeedReconnect ||
server->tcpStatus == CifsExiting ||
server->tcpStatus == CifsNew ||
(server->ops->can_echo && !server->ops->can_echo(server)) ||
time_before(jiffies, server->lstrp + server->echo_interval - HZ))
goto requeue_echo;
rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
if (rc)
cifs_dbg(FYI, "Unable to send echo request to server: %s\n",
server->hostname);
/* Check witness registrations */
cifs_swn_check();
requeue_echo:
queue_delayed_work(cifsiod_wq, &server->echo, server->echo_interval);
}
static bool
allocate_buffers(struct TCP_Server_Info *server)
{
if (!server->bigbuf) {
server->bigbuf = (char *)cifs_buf_get();
if (!server->bigbuf) {
cifs_server_dbg(VFS, "No memory for large SMB response\n");
msleep(3000);
/* retry will check if exiting */
return false;
}
} else if (server->large_buf) {
/* we are reusing a dirty large buf, clear its start */
memset(server->bigbuf, 0, HEADER_SIZE(server));
}
if (!server->smallbuf) {
server->smallbuf = (char *)cifs_small_buf_get();
if (!server->smallbuf) {
cifs_server_dbg(VFS, "No memory for SMB response\n");
msleep(1000);
/* retry will check if exiting */
return false;
}
/* beginning of smb buffer is cleared in our buf_get */
} else {
/* if existing small buf clear beginning */
memset(server->smallbuf, 0, HEADER_SIZE(server));
}
return true;
}
static bool
server_unresponsive(struct TCP_Server_Info *server)
{
/*
* We need to wait 3 echo intervals to make sure we handle such
* situations right:
* 1s client sends a normal SMB request
* 2s client gets a response
* 30s echo workqueue job pops, and decides we got a response recently
* and don't need to send another
* ...
* 65s kernel_recvmsg times out, and we see that we haven't gotten
* a response in >60s.
*/
if ((server->tcpStatus == CifsGood ||
server->tcpStatus == CifsNeedNegotiate) &&
(!server->ops->can_echo || server->ops->can_echo(server)) &&
time_after(jiffies, server->lstrp + 3 * server->echo_interval)) {
cifs_server_dbg(VFS, "has not responded in %lu seconds. Reconnecting...\n",
(3 * server->echo_interval) / HZ);
cifs_reconnect(server);
return true;
}
return false;
}
static inline bool
zero_credits(struct TCP_Server_Info *server)
{
int val;
spin_lock(&server->req_lock);
val = server->credits + server->echo_credits + server->oplock_credits;
if (server->in_flight == 0 && val == 0) {
spin_unlock(&server->req_lock);
return true;
}
spin_unlock(&server->req_lock);
return false;
}
static int
cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
{
int length = 0;
int total_read;
smb_msg->msg_control = NULL;
smb_msg->msg_controllen = 0;
for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
try_to_freeze();
/* reconnect if no credits and no requests in flight */
if (zero_credits(server)) {
cifs_reconnect(server);
return -ECONNABORTED;
}
if (server_unresponsive(server))
return -ECONNABORTED;
if (cifs_rdma_enabled(server) && server->smbd_conn)
length = smbd_recv(server->smbd_conn, smb_msg);
else
length = sock_recvmsg(server->ssocket, smb_msg, 0);
if (server->tcpStatus == CifsExiting)
return -ESHUTDOWN;
if (server->tcpStatus == CifsNeedReconnect) {
cifs_reconnect(server);
return -ECONNABORTED;
}
if (length == -ERESTARTSYS ||
length == -EAGAIN ||
length == -EINTR) {
/*
* Minimum sleep to prevent looping, allowing socket
* to clear and app threads to set tcpStatus
* CifsNeedReconnect if server hung.
*/
usleep_range(1000, 2000);
length = 0;
continue;
}
if (length <= 0) {
cifs_dbg(FYI, "Received no data or error: %d\n", length);
cifs_reconnect(server);
return -ECONNABORTED;
}
}
return total_read;
}
int
cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
unsigned int to_read)
{
struct msghdr smb_msg;
struct kvec iov = {.iov_base = buf, .iov_len = to_read};
iov_iter_kvec(&smb_msg.msg_iter, READ, &iov, 1, to_read);
return cifs_readv_from_socket(server, &smb_msg);
}
ssize_t
cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)
{
struct msghdr smb_msg;
/*
* iov_iter_discard already sets smb_msg.type and count and iov_offset
* and cifs_readv_from_socket sets msg_control and msg_controllen
* so little to initialize in struct msghdr
*/
smb_msg.msg_name = NULL;
smb_msg.msg_namelen = 0;
iov_iter_discard(&smb_msg.msg_iter, READ, to_read);
return cifs_readv_from_socket(server, &smb_msg);
}
int
cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
unsigned int page_offset, unsigned int to_read)
{
struct msghdr smb_msg;
struct bio_vec bv = {
.bv_page = page, .bv_len = to_read, .bv_offset = page_offset};
iov_iter_bvec(&smb_msg.msg_iter, READ, &bv, 1, to_read);
return cifs_readv_from_socket(server, &smb_msg);
}
static bool
is_smb_response(struct TCP_Server_Info *server, unsigned char type)
{
/*
* The first byte big endian of the length field,
* is actually not part of the length but the type
* with the most common, zero, as regular data.
*/
switch (type) {
case RFC1002_SESSION_MESSAGE:
/* Regular SMB response */
return true;
case RFC1002_SESSION_KEEP_ALIVE:
cifs_dbg(FYI, "RFC 1002 session keep alive\n");
break;
case RFC1002_POSITIVE_SESSION_RESPONSE:
cifs_dbg(FYI, "RFC 1002 positive session response\n");
break;
case RFC1002_NEGATIVE_SESSION_RESPONSE:
/*
* We get this from Windows 98 instead of an error on
* SMB negprot response.
*/
cifs_dbg(FYI, "RFC 1002 negative session response\n");
/* give server a second to clean up */
msleep(1000);
/*
* Always try 445 first on reconnect since we get NACK
* on some if we ever connected to port 139 (the NACK
* is since we do not begin with RFC1001 session
* initialize frame).
*/
cifs_set_port((struct sockaddr *)&server->dstaddr, CIFS_PORT);
cifs_reconnect(server);
break;
default:
cifs_server_dbg(VFS, "RFC 1002 unknown response type 0x%x\n", type);
cifs_reconnect(server);
}
return false;
}
void
dequeue_mid(struct mid_q_entry *mid, bool malformed)
{
#ifdef CONFIG_CIFS_STATS2
mid->when_received = jiffies;
#endif
spin_lock(&GlobalMid_Lock);
if (!malformed)
mid->mid_state = MID_RESPONSE_RECEIVED;
else
mid->mid_state = MID_RESPONSE_MALFORMED;
/*
* Trying to handle/dequeue a mid after the send_recv()
* function has finished processing it is a bug.
*/
if (mid->mid_flags & MID_DELETED)
pr_warn_once("trying to dequeue a deleted mid\n");
else {
list_del_init(&mid->qhead);
mid->mid_flags |= MID_DELETED;
}
spin_unlock(&GlobalMid_Lock);
}
static unsigned int
smb2_get_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
{
struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buffer;
/*
* SMB1 does not use credits.
*/
if (server->vals->header_preamble_size)
return 0;
return le16_to_cpu(shdr->CreditRequest);
}
static void
handle_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server,
char *buf, int malformed)
{
if (server->ops->check_trans2 &&
server->ops->check_trans2(mid, server, buf, malformed))
return;
mid->credits_received = smb2_get_credits_from_hdr(buf, server);
mid->resp_buf = buf;
mid->large_buf = server->large_buf;
/* Was previous buf put in mpx struct for multi-rsp? */
if (!mid->multiRsp) {
/* smb buffer will be freed by user thread */
if (server->large_buf)
server->bigbuf = NULL;
else
server->smallbuf = NULL;
}
dequeue_mid(mid, malformed);
}
static void clean_demultiplex_info(struct TCP_Server_Info *server)
{
int length;
/* take it off the list, if it's not already */
spin_lock(&cifs_tcp_ses_lock);
list_del_init(&server->tcp_ses_list);
spin_unlock(&cifs_tcp_ses_lock);
cancel_delayed_work_sync(&server->echo);
cancel_delayed_work_sync(&server->resolve);
spin_lock(&GlobalMid_Lock);
server->tcpStatus = CifsExiting;
spin_unlock(&GlobalMid_Lock);
wake_up_all(&server->response_q);
/* check if we have blocked requests that need to free */
spin_lock(&server->req_lock);
if (server->credits <= 0)
server->credits = 1;
spin_unlock(&server->req_lock);
/*
* Although there should not be any requests blocked on this queue it
* can not hurt to be paranoid and try to wake up requests that may
* haven been blocked when more than 50 at time were on the wire to the
* same server - they now will see the session is in exit state and get
* out of SendReceive.
*/
wake_up_all(&server->request_q);
/* give those requests time to exit */
msleep(125);
if (cifs_rdma_enabled(server))
smbd_destroy(server);
if (server->ssocket) {
sock_release(server->ssocket);
server->ssocket = NULL;
}
if (!list_empty(&server->pending_mid_q)) {
struct list_head dispose_list;
struct mid_q_entry *mid_entry;
struct list_head *tmp, *tmp2;
INIT_LIST_HEAD(&dispose_list);
spin_lock(&GlobalMid_Lock);
list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
cifs_dbg(FYI, "Clearing mid %llu\n", mid_entry->mid);
kref_get(&mid_entry->refcount);
mid_entry->mid_state = MID_SHUTDOWN;
list_move(&mid_entry->qhead, &dispose_list);
mid_entry->mid_flags |= MID_DELETED;
}
spin_unlock(&GlobalMid_Lock);
/* now walk dispose list and issue callbacks */
list_for_each_safe(tmp, tmp2, &dispose_list) {
mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
cifs_dbg(FYI, "Callback mid %llu\n", mid_entry->mid);
list_del_init(&mid_entry->qhead);
mid_entry->callback(mid_entry);
cifs_mid_q_entry_release(mid_entry);
}
/* 1/8th of sec is more than enough time for them to exit */
msleep(125);
}
if (!list_empty(&server->pending_mid_q)) {
/*
* mpx threads have not exited yet give them at least the smb
* send timeout time for long ops.
*
* Due to delays on oplock break requests, we need to wait at
* least 45 seconds before giving up on a request getting a
* response and going ahead and killing cifsd.
*/
cifs_dbg(FYI, "Wait for exit from demultiplex thread\n");
msleep(46000);
/*
* If threads still have not exited they are probably never
* coming home not much else we can do but free the memory.
*/
}
kfree(server->hostname);
kfree(server);
length = atomic_dec_return(&tcpSesAllocCount);
if (length > 0)
mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
}
static int
standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
int length;
char *buf = server->smallbuf;
unsigned int pdu_length = server->pdu_size;
/* make sure this will fit in a large buffer */
if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
server->vals->header_preamble_size) {
cifs_server_dbg(VFS, "SMB response too long (%u bytes)\n", pdu_length);
cifs_reconnect(server);
return -ECONNABORTED;
}
/* switch to large buffer if too big for a small one */
if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
server->large_buf = true;
memcpy(server->bigbuf, buf, server->total_read);
buf = server->bigbuf;
}
/* now read the rest */
length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
pdu_length - HEADER_SIZE(server) + 1
+ server->vals->header_preamble_size);
if (length < 0)
return length;
server->total_read += length;
dump_smb(buf, server->total_read);
return cifs_handle_standard(server, mid);
}
int
cifs_handle_standard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
int length;
/*
* We know that we received enough to get to the MID as we
* checked the pdu_length earlier. Now check to see
* if the rest of the header is OK. We borrow the length
* var for the rest of the loop to avoid a new stack var.
*
* 48 bytes is enough to display the header and a little bit
* into the payload for debugging purposes.
*/
length = server->ops->check_message(buf, server->total_read, server);
if (length != 0)
cifs_dump_mem("Bad SMB: ", buf,
min_t(unsigned int, server->total_read, 48));
if (server->ops->is_session_expired &&
server->ops->is_session_expired(buf)) {
cifs_reconnect(server);
return -1;
}
if (server->ops->is_status_pending &&
server->ops->is_status_pending(buf, server))
return -1;
if (!mid)
return length;
handle_mid(mid, server, buf, length);
return 0;
}
static void
smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
{
struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buffer;
int scredits, in_flight;
/*
* SMB1 does not use credits.
*/
if (server->vals->header_preamble_size)
return;
if (shdr->CreditRequest) {
spin_lock(&server->req_lock);
server->credits += le16_to_cpu(shdr->CreditRequest);
scredits = server->credits;
in_flight = server->in_flight;
spin_unlock(&server->req_lock);
wake_up(&server->request_q);
trace_smb3_add_credits(server->CurrentMid,
server->conn_id, server->hostname, scredits,
le16_to_cpu(shdr->CreditRequest), in_flight);
cifs_server_dbg(FYI, "%s: added %u credits total=%d\n",
__func__, le16_to_cpu(shdr->CreditRequest),
scredits);
}
}
static int
cifs_demultiplex_thread(void *p)
{
int i, num_mids, length;
struct TCP_Server_Info *server = p;
unsigned int pdu_length;
unsigned int next_offset;
char *buf = NULL;
struct task_struct *task_to_wake = NULL;
struct mid_q_entry *mids[MAX_COMPOUND];
char *bufs[MAX_COMPOUND];
unsigned int noreclaim_flag, num_io_timeout = 0;
noreclaim_flag = memalloc_noreclaim_save();
cifs_dbg(FYI, "Demultiplex PID: %d\n", task_pid_nr(current));
length = atomic_inc_return(&tcpSesAllocCount);
if (length > 1)
mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
set_freezable();
allow_kernel_signal(SIGKILL);
while (server->tcpStatus != CifsExiting) {
if (try_to_freeze())
continue;
if (!allocate_buffers(server))
continue;
server->large_buf = false;
buf = server->smallbuf;
pdu_length = 4; /* enough to get RFC1001 header */
length = cifs_read_from_socket(server, buf, pdu_length);
if (length < 0)
continue;
if (server->vals->header_preamble_size == 0)
server->total_read = 0;
else
server->total_read = length;
/*
* The right amount was read from socket - 4 bytes,
* so we can now interpret the length field.
*/
pdu_length = get_rfc1002_length(buf);
cifs_dbg(FYI, "RFC1002 header 0x%x\n", pdu_length);
if (!is_smb_response(server, buf[0]))
continue;
next_pdu:
server->pdu_size = pdu_length;
/* make sure we have enough to get to the MID */
if (server->pdu_size < HEADER_SIZE(server) - 1 -
server->vals->header_preamble_size) {
cifs_server_dbg(VFS, "SMB response too short (%u bytes)\n",
server->pdu_size);
cifs_reconnect(server);
continue;
}
/* read down to the MID */
length = cifs_read_from_socket(server,
buf + server->vals->header_preamble_size,
HEADER_SIZE(server) - 1
- server->vals->header_preamble_size);
if (length < 0)
continue;
server->total_read += length;
if (server->ops->next_header) {
next_offset = server->ops->next_header(buf);
if (next_offset)
server->pdu_size = next_offset;
}
memset(mids, 0, sizeof(mids));
memset(bufs, 0, sizeof(bufs));
num_mids = 0;
if (server->ops->is_transform_hdr &&
server->ops->receive_transform &&
server->ops->is_transform_hdr(buf)) {
length = server->ops->receive_transform(server,
mids,
bufs,
&num_mids);
} else {
mids[0] = server->ops->find_mid(server, buf);
bufs[0] = buf;
num_mids = 1;