Merge with Linux 2.5.48.

[linux-2.6/linux-mips.git] / fs / smbfs / request.c

/*
 *  request.c
 *
 *  Copyright (C) 2001 by Urban Widmark
 *
 *  Please add a note about your changes to smbfs in the ChangeLog file.
 */

#include <linux/types.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/net.h>

#include <linux/smb_fs.h>
#include <linux/smbno.h>
#include <linux/smb_mount.h>

#include "smb_debug.h"
#include "request.h"
#include "proto.h"

/* #define SMB_SLAB_DEBUG       (SLAB_RED_ZONE | SLAB_POISON) */
#define SMB_SLAB_DEBUG  0

#define ROUND_UP(x) (((x)+3) & ~3)

/* cache for request structures */
static kmem_cache_t *req_cachep;

/*
  /proc/slabinfo:
  name, active, num, objsize, active_slabs, num_slaps, #pages
*/


int smb_init_request_cache(void)
{
        req_cachep = kmem_cache_create("smb_request",
                                       sizeof(struct smb_request), 0,
                                       SMB_SLAB_DEBUG | SLAB_HWCACHE_ALIGN,
                                       NULL, NULL);
        if (req_cachep == NULL)
                return -ENOMEM;

        return 0;
}

void smb_destroy_request_cache(void)
{
        if (kmem_cache_destroy(req_cachep))
                printk(KERN_INFO "smb_destroy_request_cache: not all structures were freed\n");
}

/*
 * Allocate and initialise a request structure
 */
static struct smb_request *smb_do_alloc_request(struct smb_sb_info *server,
                                                int bufsize)
{
        struct smb_request *req;
        unsigned char *buf = NULL;

        req = kmem_cache_alloc(req_cachep, SLAB_KERNEL);
        VERBOSE("allocating request: %p\n", req);
        if (!req)
                goto out;

        if (bufsize > 0) {
                buf = smb_kmalloc(bufsize, GFP_NOFS);
                if (!buf) {
                        kmem_cache_free(req_cachep, req);
                        return NULL;
                }
        }

        memset(req, 0, sizeof(struct smb_request));
        req->rq_buffer = buf;
        req->rq_bufsize = bufsize;
        req->rq_server = server;
        init_waitqueue_head(&req->rq_wait);
        INIT_LIST_HEAD(&req->rq_queue);
        atomic_set(&req->rq_count, 1);

out:
        return req;
}

struct smb_request *smb_alloc_request(struct smb_sb_info *server, int bufsize)
{
        struct smb_request *req = NULL;

        for (;;) {
                atomic_inc(&server->nr_requests);
                if (atomic_read(&server->nr_requests) <= MAX_REQUEST_HARD) {
                        req = smb_do_alloc_request(server, bufsize);
                        if (req != NULL)
                                break;
                }

#if 0
                /*
                 * Try to free up at least one request in order to stay
                 * below the hard limit
                 */
                if (nfs_try_to_free_pages(server))
                        continue;

                if (signalled() && (server->flags & NFS_MOUNT_INTR))
                        return ERR_PTR(-ERESTARTSYS);
                current->policy = SCHED_YIELD;
                schedule();
#else
                /* FIXME: we want something like nfs does above, but that
                   requires changes to all callers and can wait. */
                break;
#endif
        }
        return req;
}

static void smb_free_request(struct smb_request *req)
{
        atomic_dec(&req->rq_server->nr_requests);
        if (req->rq_buffer && !(req->rq_flags & SMB_REQ_STATIC))
                smb_kfree(req->rq_buffer);
        if (req->rq_trans2buffer)
                smb_kfree(req->rq_trans2buffer);
        kmem_cache_free(req_cachep, req);
}

/*
 * What prevents a rget to race with a rput? The count must never drop to zero
 * while it is in use. Only rput if it is ok that it is free'd.
 */
void smb_rget(struct smb_request *req)
{
        atomic_inc(&req->rq_count);
}
void smb_rput(struct smb_request *req)
{
        if (atomic_dec_and_test(&req->rq_count)) {
                list_del_init(&req->rq_queue);
                smb_free_request(req);
        }
}

/* setup to receive the data part of the SMB */
static int smb_setup_bcc(struct smb_request *req)
{
        int result = 0;
        req->rq_rlen = smb_len(req->rq_header) + 4 - req->rq_bytes_recvd;

        if (req->rq_rlen > req->rq_bufsize) {
                PARANOIA("Packet too large %d > %d\n",
                         req->rq_rlen, req->rq_bufsize);
                return -ENOBUFS;
        }

        req->rq_iov[0].iov_base = req->rq_buffer;
        req->rq_iov[0].iov_len  = req->rq_rlen;
        req->rq_iovlen = 1;

        return result;
}

/*
 * Prepare a "normal" request structure.
 */
static int smb_setup_request(struct smb_request *req)
{
        int len = smb_len(req->rq_header) + 4;
        req->rq_slen = len;

        /* if we expect a data part in the reply we set the iov's to read it */
        if (req->rq_resp_bcc)
                req->rq_setup_read = smb_setup_bcc;

        /* This tries to support re-using the same request */
        req->rq_bytes_sent = 0;
        req->rq_rcls = 0;
        req->rq_err = 0;
        req->rq_errno = 0;
        req->rq_fragment = 0;
        if (req->rq_trans2buffer)
                smb_kfree(req->rq_trans2buffer);

        return 0;
}

/*
 * Prepare a transaction2 request structure
 */
static int smb_setup_trans2request(struct smb_request *req)
{
        struct smb_sb_info *server = req->rq_server;
        int mparam, mdata;
        static unsigned char padding[4] = { 0, };

        /* I know the following is very ugly, but I want to build the
           smb packet as efficiently as possible. */

        const int smb_parameters = 15;
        const int header = SMB_HEADER_LEN + 2 * smb_parameters + 2;
        const int oparam = ROUND_UP(header + 3);
        const int odata  = ROUND_UP(oparam + req->rq_lparm);
        const int bcc = (req->rq_data ? odata + req->rq_ldata :
                                        oparam + req->rq_lparm) - header;

        if ((bcc + oparam) > server->opt.max_xmit)
                return -ENOMEM;
        smb_setup_header(req, SMBtrans2, smb_parameters, bcc);

        /*
         * max parameters + max data + max setup == bufsize to make NT4 happy
         * and not abort the transfer or split into multiple responses. It also
         * makes smbfs happy as handling packets larger than the buffer size
         * is extra work.
         *
         * OS/2 is probably going to hate me for this ...
         */
        mparam = SMB_TRANS2_MAX_PARAM;
        mdata = req->rq_bufsize - mparam;

        mdata = server->opt.max_xmit - mparam - 100;
        if (mdata < 1024) {
                mdata = 1024;
                mparam = 20;
        }

#if 0
        /* NT/win2k has ~4k max_xmit, so with this we request more than it wants
           to return as one SMB. Useful for testing the fragmented trans2
           handling. */
        mdata = 8192;
#endif

        WSET(req->rq_header, smb_tpscnt, req->rq_lparm);
        WSET(req->rq_header, smb_tdscnt, req->rq_ldata);
        WSET(req->rq_header, smb_mprcnt, mparam);
        WSET(req->rq_header, smb_mdrcnt, mdata);
        WSET(req->rq_header, smb_msrcnt, 0);    /* max setup always 0 ? */
        WSET(req->rq_header, smb_flags, 0);
        DSET(req->rq_header, smb_timeout, 0);
        WSET(req->rq_header, smb_pscnt, req->rq_lparm);
        WSET(req->rq_header, smb_psoff, oparam - 4);
        WSET(req->rq_header, smb_dscnt, req->rq_ldata);
        WSET(req->rq_header, smb_dsoff, req->rq_data ? odata - 4 : 0);
        *(req->rq_header + smb_suwcnt) = 0x01;          /* setup count */
        *(req->rq_header + smb_suwcnt + 1) = 0x00;      /* reserved */
        WSET(req->rq_header, smb_setup0, req->rq_trans2_command);

        req->rq_iovlen = 2;
        req->rq_iov[0].iov_base = (void *) req->rq_header;
        req->rq_iov[0].iov_len = oparam;
        req->rq_iov[1].iov_base = (req->rq_parm==NULL) ? padding : req->rq_parm;
        req->rq_iov[1].iov_len = req->rq_lparm;
        req->rq_slen = oparam + req->rq_lparm;

        if (req->rq_data) {
                req->rq_iovlen += 2;
                req->rq_iov[2].iov_base = padding;
                req->rq_iov[2].iov_len = odata - oparam - req->rq_lparm;
                req->rq_iov[3].iov_base = req->rq_data;
                req->rq_iov[3].iov_len = req->rq_ldata;
                req->rq_slen = odata + req->rq_ldata;
        }

        /* always a data part for trans2 replies */
        req->rq_setup_read = smb_setup_bcc;

        return 0;
}

/*
 * Add a request and tell smbiod to process it
 */
int smb_add_request(struct smb_request *req)
{
        long timeleft;
        struct smb_sb_info *server = req->rq_server;
        int result = 0;

        smb_setup_request(req);
        if (req->rq_trans2_command) {
                if (req->rq_buffer == NULL) {
                        PARANOIA("trans2 attempted without response buffer!\n");
                        return -EIO;
                }
                result = smb_setup_trans2request(req);
        }
        if (result < 0)
                return result;

#ifdef SMB_DEBUG_PACKET_SIZE
        add_xmit_stats(req);
#endif

        /* add 'req' to the queue of requests */
        if (smb_lock_server_interruptible(server))
                return -EINTR;

        /*
         * Try to send the request as the process. If that fails we queue the
         * request and let smbiod send it later.
         */

        /* FIXME: each server has a number on the maximum number of parallel
           requests. 10, 50 or so. We should not allow more requests to be
           active. */
        if (server->mid > 0xf000)
                server->mid = 0;
        req->rq_mid = server->mid++;
        WSET(req->rq_header, smb_mid, req->rq_mid);

        result = 0;
        if (server->state == CONN_VALID) {
                if (list_empty(&server->xmitq))
                        result = smb_request_send_req(req);
                if (result < 0) {
                        /* Connection lost? */
                        server->conn_error = result;
                        server->state = CONN_INVALID;
                }
        }
        if (result != 1)
                list_add_tail(&req->rq_queue, &server->xmitq);
        smb_rget(req);

        if (server->state != CONN_VALID)
                smbiod_retry(server);

        smb_unlock_server(server);

        smbiod_wake_up();

        timeleft = wait_event_interruptible_timeout(req->rq_wait,
                                    req->rq_flags & SMB_REQ_RECEIVED, 30*HZ);
        if (!timeleft || signal_pending(current)) {
                /*
                 * On timeout or on interrupt we want to try and remove the
                 * request from the recvq/xmitq.
                 */
                smb_lock_server(server);
                if (!(req->rq_flags & SMB_REQ_RECEIVED)) {
                        list_del_init(&req->rq_queue);
                        smb_rput(req);
                }
                smb_unlock_server(server);
        }

        if (!timeleft) {
                PARANOIA("request [%p, mid=%d] timed out!\n",
                         req, req->rq_mid);
                VERBOSE("smb_com:  %02x\n", *(req->rq_header + smb_com));
                VERBOSE("smb_rcls: %02x\n", *(req->rq_header + smb_rcls));
                VERBOSE("smb_flg:  %02x\n", *(req->rq_header + smb_flg));
                VERBOSE("smb_tid:  %04x\n", WVAL(req->rq_header, smb_tid));
                VERBOSE("smb_pid:  %04x\n", WVAL(req->rq_header, smb_pid));
                VERBOSE("smb_uid:  %04x\n", WVAL(req->rq_header, smb_uid));
                VERBOSE("smb_mid:  %04x\n", WVAL(req->rq_header, smb_mid));
                VERBOSE("smb_wct:  %02x\n", *(req->rq_header + smb_wct));

                req->rq_rcls = ERRSRV;
                req->rq_err  = ERRtimeout;

                /* Just in case it was "stuck" */
                smbiod_wake_up();
        }
        VERBOSE("woke up, rcls=%d\n", req->rq_rcls);

        if (req->rq_rcls != 0)
                req->rq_errno = smb_errno(req);
        if (signal_pending(current))
                req->rq_errno = -ERESTARTSYS;
        return req->rq_errno;
}

/*
 * Send a request and place it on the recvq if successfully sent.
 * Must be called with the server lock held.
 */
int smb_request_send_req(struct smb_request *req)
{
        struct smb_sb_info *server = req->rq_server;
        int result;

        result = smb_send_request(req);
        if (result < 0 && result != -EAGAIN)
                goto out;

        result = 0;
        if (!(req->rq_flags & SMB_REQ_TRANSMITTED))
                goto out;

        list_del_init(&req->rq_queue);
        list_add_tail(&req->rq_queue, &server->recvq);
        result = 1;
out:
        return result;
}

/*
 * Sends one request for this server. (smbiod)
 * Must be called with the server lock held.
 * Returns: <0 on error
 *           0 if no request could be completely sent
 *           1 if all data for one request was sent
 */
int smb_request_send_server(struct smb_sb_info *server)
{
        struct list_head *head;
        struct smb_request *req;
        int result;

        if (server->state != CONN_VALID)
                return 0;

        /* dequeue first request, if any */
        req = NULL;
        head = server->xmitq.next;
        if (head != &server->xmitq) {
                req = list_entry(head, struct smb_request, rq_queue);
        }
        if (!req)
                return 0;

        result = smb_request_send_req(req);
        if (result < 0) {
                server->conn_error = result;
                list_del_init(&req->rq_queue);
                list_add(&req->rq_queue, &server->xmitq);
                result = -EIO;
                goto out;
        }

out:
        return result;
}

/*
 * Try to find a request matching this "mid". Typically the first entry will
 * be the matching one.
 */
static struct smb_request *find_request(struct smb_sb_info *server, int mid)
{
        struct list_head *tmp;
        struct smb_request *req = NULL;

        list_for_each(tmp, &server->recvq) {
                req = list_entry(tmp, struct smb_request, rq_queue);
                if (req->rq_mid == mid) {
                        break;
                }
                req = NULL;
        }

        if (!req) {
                VERBOSE("received reply with mid %d but no request!\n",
                        WVAL(server->header, smb_mid));
                server->rstate = SMB_RECV_DROP;
        }

        return req;
}

/*
 * Called when we have read the smb header and believe this is a response.
 */
static int smb_init_request(struct smb_sb_info *server, struct smb_request *req)
{
        int hdrlen, wct;

        memcpy(req->rq_header, server->header, SMB_HEADER_LEN);

        wct = *(req->rq_header + smb_wct);
        if (wct > 20) { 
                PARANOIA("wct too large, %d > 20\n", wct);
                server->rstate = SMB_RECV_DROP;
                return 0;
        }

        req->rq_resp_wct = wct;
        hdrlen = SMB_HEADER_LEN + wct*2 + 2;
        VERBOSE("header length: %d   smb_wct: %2d\n", hdrlen, wct);

        req->rq_bytes_recvd = SMB_HEADER_LEN;
        req->rq_rlen = hdrlen;
        req->rq_iov[0].iov_base = req->rq_header;
        req->rq_iov[0].iov_len  = hdrlen;
        req->rq_iovlen = 1;
        server->rstate = SMB_RECV_PARAM;

#ifdef SMB_DEBUG_PACKET_SIZE
        add_recv_stats(smb_len(server->header));
#endif
        return 0;
}

/*
 * Reads the SMB parameters
 */
static int smb_recv_param(struct smb_sb_info *server, struct smb_request *req)
{
        int result;

        result = smb_receive(server, req);
        if (result < 0)
                return result;
        if (req->rq_bytes_recvd < req->rq_rlen)
                return 0;

        VERBOSE("result: %d   smb_bcc:  %04x\n", result,
                WVAL(req->rq_header, SMB_HEADER_LEN +
                     (*(req->rq_header + smb_wct) * 2)));

        result = 0;
        req->rq_iov[0].iov_base = NULL;
        req->rq_rlen = 0;
        if (req->rq_callback)
                req->rq_callback(req);
        else if (req->rq_setup_read)
                result = req->rq_setup_read(req);
        if (result < 0) {
                server->rstate = SMB_RECV_DROP;
                return result;
        }

        server->rstate = req->rq_rlen > 0 ? SMB_RECV_DATA : SMB_RECV_END;

        req->rq_bytes_recvd = 0;        // recvd out of the iov

        VERBOSE("rlen: %d\n", req->rq_rlen);
        if (req->rq_rlen < 0) {
                PARANOIA("Parameters read beyond end of packet!\n");
                server->rstate = SMB_RECV_END;
                return -EIO;
        }
        return 0;
}

/*
 * Reads the SMB data
 */
static int smb_recv_data(struct smb_sb_info *server, struct smb_request *req)
{
        int result;

        result = smb_receive(server, req);
        if (result < 0)
                goto out;
        if (req->rq_bytes_recvd < req->rq_rlen)
                goto out;
        server->rstate = SMB_RECV_END;
out:
        VERBOSE("result: %d\n", result);
        return result;
}

/*
 * Receive a transaction2 response
 * Return: 0 if the response has been fully read
 *         1 if there are further "fragments" to read
 *        <0 if there is an error
 */
static int smb_recv_trans2(struct smb_sb_info *server, struct smb_request *req)
{
        unsigned char *inbuf;
        unsigned int parm_disp, parm_offset, parm_count, parm_tot;
        unsigned int data_disp, data_offset, data_count, data_tot;
        int hdrlen = SMB_HEADER_LEN + req->rq_resp_wct*2 - 2;

        VERBOSE("handling trans2\n");

        inbuf = req->rq_header;
        data_tot    = WVAL(inbuf, smb_tdrcnt);
        parm_tot    = WVAL(inbuf, smb_tprcnt);
        parm_disp   = WVAL(inbuf, smb_prdisp);
        parm_offset = WVAL(inbuf, smb_proff);
        parm_count  = WVAL(inbuf, smb_prcnt);
        data_disp   = WVAL(inbuf, smb_drdisp);
        data_offset = WVAL(inbuf, smb_droff);
        data_count  = WVAL(inbuf, smb_drcnt);

        /* Modify offset for the split header/buffer we use */
        data_offset -= hdrlen;
        parm_offset -= hdrlen;

        if (parm_count == parm_tot && data_count == data_tot) {
                /*
                 * This packet has all the trans2 data.
                 *
                 * We setup the request so that this will be the common
                 * case. It may be a server error to not return a
                 * response that fits.
                 */
                VERBOSE("single trans2 response  "
                        "dcnt=%d, pcnt=%d, doff=%d, poff=%d\n",
                        data_count, parm_count,
                        data_offset, parm_offset);
                req->rq_ldata = data_count;
                req->rq_lparm = parm_count;
                req->rq_data = req->rq_buffer + data_offset;
                req->rq_parm = req->rq_buffer + parm_offset;
                return 0;
        }

        VERBOSE("multi trans2 response  "
                "frag=%d, dcnt=%d, pcnt=%d, doff=%d, poff=%d\n",
                req->rq_fragment,
                data_count, parm_count,
                data_offset, parm_offset);

        if (!req->rq_fragment) {
                int buf_len;

                /* We got the first trans2 fragment */
                req->rq_fragment = 1;
                req->rq_total_data = data_tot;
                req->rq_total_parm = parm_tot;
                req->rq_ldata = 0;
                req->rq_lparm = 0;

                buf_len = data_tot + parm_tot;
                if (buf_len > SMB_MAX_PACKET_SIZE)
                        goto out_too_long;

                req->rq_trans2bufsize = buf_len;
                req->rq_trans2buffer = smb_kmalloc(buf_len, GFP_NOFS);
                if (!req->rq_trans2buffer)
                        goto out_no_mem;

                req->rq_parm = req->rq_trans2buffer;
                req->rq_data = req->rq_trans2buffer + parm_tot;
        } else if (req->rq_total_data < data_tot ||
                   req->rq_total_parm < parm_tot)
                goto out_data_grew;

        if (parm_disp + parm_count > req->rq_total_parm)
                goto out_bad_parm;
        if (data_disp + data_count > req->rq_total_data)
                goto out_bad_data;

        inbuf = req->rq_buffer;
        memcpy(req->rq_parm + parm_disp, inbuf + parm_offset, parm_count);
        memcpy(req->rq_data + data_disp, inbuf + data_offset, data_count);

        req->rq_ldata += data_count;
        req->rq_lparm += parm_count;

        /*
         * Check whether we've received all of the data. Note that
         * we use the packet totals -- total lengths might shrink!
         */
        if (req->rq_ldata >= data_tot && req->rq_lparm >= parm_tot)
                return 0;
        return 1;

out_too_long:
        printk(KERN_ERR "smb_trans2: data/param too long, data=%d, parm=%d\n",
                data_tot, parm_tot);
        req->rq_errno = -EIO;
        goto out;
out_no_mem:
        printk(KERN_ERR "smb_trans2: couldn't allocate data area of %d bytes\n",
               req->rq_trans2bufsize);
        req->rq_errno = -ENOMEM;
        goto out;
out_data_grew:
        printk(KERN_ERR "smb_trans2: data/params grew!\n");
        req->rq_errno = -EIO;
        goto out;
out_bad_parm:
        printk(KERN_ERR "smb_trans2: invalid parms, disp=%d, cnt=%d, tot=%d\n",
               parm_disp, parm_count, parm_tot);
        req->rq_errno = -EIO;
        goto out;
out_bad_data:
        printk(KERN_ERR "smb_trans2: invalid data, disp=%d, cnt=%d, tot=%d\n",
               data_disp, data_count, data_tot);
        req->rq_errno = -EIO;
out:
        return req->rq_errno;
}

/*
 * State machine for receiving responses. We handle the fact that we can't
 * read the full response in one try by having states telling us how much we
 * have read.
 *
 * Must be called with the server lock held (only called from smbiod).
 *
 * Return: <0 on error
 */
int smb_request_recv(struct smb_sb_info *server)
{
        struct smb_request *req = NULL;
        int result = 0;

        if (smb_recv_available(server) <= 0)
                return 0;

        VERBOSE("state: %d\n", server->rstate);
        switch (server->rstate) {
        case SMB_RECV_DROP:
                result = smb_receive_drop(server);
                if (result < 0)
                        break;
                if (server->rstate == SMB_RECV_DROP)
                        break;
                server->rstate = SMB_RECV_START;
                /* fallthrough */
        case SMB_RECV_START:
                server->smb_read = 0;
                server->rstate = SMB_RECV_HEADER;
                /* fallthrough */
        case SMB_RECV_HEADER:
                result = smb_receive_header(server);
                if (result < 0)
                        break;
                if (server->rstate == SMB_RECV_HEADER)
                        break;
                if (! (*(server->header + smb_flg) & SMB_FLAGS_REPLY) ) {
                        server->rstate = SMB_RECV_REQUEST;
                        break;
                }
                if (server->rstate != SMB_RECV_HCOMPLETE)
                        break;
                /* fallthrough */
        case SMB_RECV_HCOMPLETE:
                req = find_request(server, WVAL(server->header, smb_mid));
                if (!req)
                        break;
                smb_init_request(server, req);
                req->rq_rcls = *(req->rq_header + smb_rcls);
                req->rq_err  = WVAL(req->rq_header, smb_err);
                if (server->rstate != SMB_RECV_PARAM)
                        break;
                /* fallthrough */
        case SMB_RECV_PARAM:
                if (!req)
                        req = find_request(server,WVAL(server->header,smb_mid));
                if (!req)
                        break;
                result = smb_recv_param(server, req);
                if (result < 0)
                        break;
                if (server->rstate != SMB_RECV_DATA)
                        break;
                /* fallthrough */
        case SMB_RECV_DATA:
                if (!req)
                        req = find_request(server,WVAL(server->header,smb_mid));
                if (!req)
                        break;
                result = smb_recv_data(server, req);
                if (result < 0)
                        break;
                break;

                /* We should never be called with any of these states */
        case SMB_RECV_END:
        case SMB_RECV_REQUEST:
                server->rstate = SMB_RECV_END;
                break;
        }

        if (result < 0) {
                /* We saw an error */
                return result;
        }

        if (server->rstate != SMB_RECV_END)
                return 0;

        result = 0;
        if (req->rq_trans2_command && req->rq_rcls == SUCCESS)
                result = smb_recv_trans2(server, req);

        /*
         * Response completely read. Drop any extra bytes sent by the server.
         * (Yes, servers sometimes add extra bytes to responses)
         */
        VERBOSE("smb_len: %d   smb_read: %d\n",
                server->smb_len, server->smb_read);
        if (server->smb_read < server->smb_len)
                smb_receive_drop(server);

        server->rstate = SMB_RECV_START;

        if (!result) {
                list_del_init(&req->rq_queue);
                req->rq_flags |= SMB_REQ_RECEIVED;
                smb_rput(req);
                wake_up_interruptible(&req->rq_wait);
        }
        return 0;
}