nbt.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

/* Copyright (c) 2003 Juan Lang
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 *
 * I am heavily indebted to Chris Hertel's excellent Implementing CIFS,
 * http://ubiqx.org/cifs/ , for whatever understanding I have of NBT.
 * I also stole from Mike McCormack's smb.c and netapi32.c, although little of
 * that code remains.
 * Lack of understanding and bugs are my fault.
 *
 * FIXME:
 * - Of the NetBIOS session functions, only client functions are supported, and
 *   it's likely they'll be the only functions supported.  NBT requires session
 *   servers to listen on TCP/139.  This requires root privilege, and Samba is
 *   likely to be listening here already.  This further restricts NetBIOS
 *   applications, both explicit users and implicit ones:  CreateNamedPipe
 *   won't actually create a listening pipe, for example, so applications can't
 *   act as RPC servers using a named pipe protocol binding, DCOM won't be able
 *   to support callbacks or servers over the named pipe protocol, etc.
 *
 * - Datagram support is omitted for the same reason.  To send a NetBIOS
 *   datagram, you must include the NetBIOS name by which your application is
 *   known.  This requires you to have registered the name previously, and be
 *   able to act as a NetBIOS datagram server (listening on UDP/138).
 *
 * - Name registration functions are omitted for the same reason--registering a
 *   name requires you to be able to defend it, and this means listening on
 *   UDP/137.
 *   Win98 requires you either use your computer's NetBIOS name (with the NULL
 *   suffix byte) as the calling name when creating a session, or to register
 *   a new name before creating one:  it disallows '*' as the calling name.
 *   Win2K initially starts with an empty name table, and doesn't allow you to
 *   use the machine's NetBIOS name (with the NULL suffix byte) as the calling
 *   name.  Although it allows sessions to be created with '*' as the calling
 *   name, doing so results in timeouts for all receives, because the
 *   application never gets them.
 *   So, a well-behaved Netbios application will typically want to register a
 *   name.  I should probably support a do-nothing name list that allows
 *   NCBADDNAME to add to it, but doesn't actually register the name, or does
 *   attempt to register it without being able to defend it.
 *
 * - Name lookups may not behave quite as you'd expect/like if you have
 *   multiple LANAs.  If a name is resolvable through DNS, or if you're using
 *   WINS, it'll resolve on _any_ LANA.  So, a Call will succeed on any LANA as
 *   well.
 *   I'm not sure how Windows behaves in this case.  I could try to force
 *   lookups to the correct adapter by using one of the GetPreferred*
 *   functions, but with the possibility of multiple adapters in the same
 *   same subnet, there's no guarantee that what IpHlpApi thinks is the
 *   preferred adapter will actually be a LANA.  (It's highly probable because
 *   this is an unusual configuration, but not guaranteed.)
 *
 * See also other FIXMEs in the code.
 */

#include "config.h"
#include <stdarg.h>

#include "winsock2.h"
#include "windef.h"
#include "winbase.h"
#include "wine/debug.h"
#include "winreg.h"
#include "iphlpapi.h"

#include "netbios.h"
#include "nbnamecache.h"

WINE_DEFAULT_DEBUG_CHANNEL(netbios);

#define PORT_NBNS 137
#define PORT_NBDG 138
#define PORT_NBSS 139

#ifndef INADDR_NONE
#define INADDR_NONE ~0UL
#endif

#define NBR_ADDWORD(p,word) (*(WORD *)(p)) = htons(word)
#define NBR_GETWORD(p) ntohs(*(WORD *)(p))

#define MIN_QUERIES         1
#define MAX_QUERIES         0xffff
#define MIN_QUERY_TIMEOUT   100
#define MAX_QUERY_TIMEOUT   0xffffffff
#define BCAST_QUERIES       3
#define BCAST_QUERY_TIMEOUT 750
#define WINS_QUERIES        3
#define WINS_QUERY_TIMEOUT  750
#define MAX_WINS_SERVERS    2
#define MIN_CACHE_TIMEOUT   60000
#define CACHE_TIMEOUT       360000

#define MAX_NBT_NAME_SZ (NCBNAMSZ * 2 + MAX_DOMAIN_NAME_LEN + 2)
#define SIMPLE_NAME_QUERY_PKT_SIZE 26 + MAX_NBT_NAME_SZ

#define DEFAULT_NBT_SESSIONS 16

#define NBNS_TYPE_NB             0x0020
#define NBNS_TYPE_NBSTAT         0x0021
#define NBNS_CLASS_INTERNET      0x00001
#define NBNS_HEADER_SIZE         (sizeof(WORD) * 6)
#define NBNS_RESPONSE_AND_OPCODE 0xf800
#define NBNS_RESPONSE_AND_QUERY  0x8000
#define NBNS_REPLYCODE           0x0f

#define NBSS_HDRSIZE 4

#define NBSS_MSG       0x00
#define NBSS_REQ       0x81
#define NBSS_ACK       0x82
#define NBSS_NACK      0x83
#define NBSS_RETARGET  0x84
#define NBSS_KEEPALIVE 0x85

#define NBSS_ERR_NOT_LISTENING_ON_NAME    0x80
#define NBSS_ERR_NOT_LISTENING_FOR_CALLER 0x81
#define NBSS_ERR_BAD_NAME                 0x82
#define NBSS_ERR_INSUFFICIENT_RESOURCES   0x83

#define NBSS_EXTENSION 0x01

typedef struct _NetBTSession
{
    CRITICAL_SECTION cs;
    SOCKET           fd;
    DWORD            bytesPending;
} NetBTSession;

typedef struct _NetBTAdapter
{
    MIB_IPADDRROW       ipr;
    WORD                nameQueryXID;
    struct NBNameCache *nameCache;
    DWORD               xmit_success;
    DWORD               recv_success;
} NetBTAdapter;

static ULONG gTransportID;
static BOOL  gEnableDNS;
static DWORD gBCastQueries;
static DWORD gBCastQueryTimeout;
static DWORD gWINSQueries;
static DWORD gWINSQueryTimeout;
static DWORD gWINSServers[MAX_WINS_SERVERS];
static int   gNumWINSServers;
static char  gScopeID[MAX_DOMAIN_NAME_LEN];
static DWORD gCacheTimeout;
static struct NBNameCache *gNameCache;

/* Converts from a NetBIOS name into a Second Level Encoding-formatted name.
 * Assumes p is not NULL and is either NULL terminated or has at most NCBNAMSZ
 * bytes, and buffer has at least MAX_NBT_NAME_SZ bytes.  Pads with space bytes
 * if p is NULL-terminated.  Returns the number of bytes stored in buffer.
 */
static int NetBTNameEncode(const UCHAR *p, UCHAR *buffer)
{
    int i,len=0;

    if (!p) return 0;
    if (!buffer) return 0;

    buffer[len++] = NCBNAMSZ * 2;
    for (i = 0; p[i] && i < NCBNAMSZ; i++)
    {
        buffer[len++] = ((p[i] & 0xf0) >> 4) + 'A';
        buffer[len++] =  (p[i] & 0x0f) + 'A';
    }
    while (len < NCBNAMSZ * 2)
    {
        buffer[len++] = 'C';
        buffer[len++] = 'A';
    }
    if (*gScopeID)
    {
        int scopeIDLen = strlen(gScopeID);

        memcpy(buffer + len, gScopeID, scopeIDLen);
        len += scopeIDLen;
    }
    buffer[len++] = 0;     /* add second terminator */
    return len;
}

/* Creates a NBT name request packet for name in buffer.  If broadcast is true,
 * creates a broadcast request, otherwise creates a unicast request.
 * Returns the number of bytes stored in buffer.
 */
static DWORD NetBTNameReq(const UCHAR name[NCBNAMSZ], WORD xid, WORD qtype,
 BOOL broadcast, UCHAR *buffer, int len)
{
    int i = 0;

    if (len < SIMPLE_NAME_QUERY_PKT_SIZE) return 0;

    NBR_ADDWORD(&buffer[i],xid);    i+=2; /* transaction */
    if (broadcast)
    {
        NBR_ADDWORD(&buffer[i],0x0110); /* flags: r=req,op=query,rd=1,b=1 */
        i+=2;
    }
    else
    {
        NBR_ADDWORD(&buffer[i],0x0100); /* flags: r=req,op=query,rd=1,b=0 */
        i+=2;
    }
    NBR_ADDWORD(&buffer[i],0x0001); i+=2; /* one name query */
    NBR_ADDWORD(&buffer[i],0x0000); i+=2; /* zero answers */
    NBR_ADDWORD(&buffer[i],0x0000); i+=2; /* zero authorities */
    NBR_ADDWORD(&buffer[i],0x0000); i+=2; /* zero additional */

    i += NetBTNameEncode(name, &buffer[i]);

    NBR_ADDWORD(&buffer[i],qtype); i+=2;
    NBR_ADDWORD(&buffer[i],NBNS_CLASS_INTERNET); i+=2;

    return i;
}

/* Sends a name query request for name on fd to destAddr.  Sets SO_BROADCAST on
 * fd if broadcast is TRUE.  Assumes fd is not INVALID_SOCKET, and name is not
 * NULL.
 * Returns 0 on success, -1 on failure.
 */
static int NetBTSendNameQuery(SOCKET fd, const UCHAR name[NCBNAMSZ], WORD xid,
 WORD qtype, DWORD destAddr, BOOL broadcast)
{
    int ret = 0, on = 1;
    struct in_addr addr;

    addr.s_addr = destAddr;
    TRACE("name %s, dest addr %s\n", name, inet_ntoa(addr));

    if (broadcast)
        ret = setsockopt(fd, SOL_SOCKET, SO_BROADCAST, (const char*)&on, sizeof(on));
    if(ret == 0)
    {
        WSABUF wsaBuf;
        UCHAR buf[SIMPLE_NAME_QUERY_PKT_SIZE];
        struct sockaddr_in sin;

        memset(&sin, 0, sizeof(sin));
        sin.sin_addr.s_addr = destAddr;
        sin.sin_family      = AF_INET;
        sin.sin_port        = htons(PORT_NBNS);

        wsaBuf.buf = (CHAR*)buf;
        wsaBuf.len = NetBTNameReq(name, xid, qtype, broadcast, buf,
         sizeof(buf));
        if (wsaBuf.len > 0)
        {
            DWORD bytesSent;

            ret = WSASendTo(fd, &wsaBuf, 1, &bytesSent, 0,
             (struct sockaddr*)&sin, sizeof(sin), NULL, NULL);
            if (ret < 0 || bytesSent < wsaBuf.len)
                ret = -1;
            else
                ret = 0;
        }
        else
            ret = -1;
    }
    return ret;
}

typedef BOOL (*NetBTAnswerCallback)(void *data, WORD answerCount,
 WORD answerIndex, PUCHAR rData, WORD rdLength);

/* Waits on fd until GetTickCount() returns a value greater than or equal to
 * waitUntil for a name service response.  If a name response matching xid
 * is received, calls answerCallback once for each answer resource record in
 * the response.  (The callback's answerCount will be the total number of
 * answers to expect, and answerIndex will be the 0-based index that's being
 * sent this time.)  Quits parsing if answerCallback returns FALSE.
 * Returns NRC_GOODRET on timeout or a valid response received, something else
 * on error.
 */
static UCHAR NetBTWaitForNameResponse(const NetBTAdapter *adapter, SOCKET fd,
 DWORD waitUntil, NetBTAnswerCallback answerCallback, void *data)
{
    BOOL found = FALSE;
    DWORD now;
    UCHAR ret = NRC_GOODRET;

    if (!adapter) return NRC_BADDR;
    if (fd == INVALID_SOCKET) return NRC_BADDR;
    if (!answerCallback) return NRC_BADDR;

    while (!found && ret == NRC_GOODRET && (now = GetTickCount()) < waitUntil)
    {
        DWORD msToWait = waitUntil - now;
        struct fd_set fds;
        struct timeval timeout = { msToWait / 1000, msToWait % 1000 };
        int r;

        FD_ZERO(&fds);
        FD_SET(fd, &fds);
        r = select(fd + 1, &fds, NULL, NULL, &timeout);
        if (r < 0)
            ret = NRC_SYSTEM;
        else if (r == 1)
        {
            /* FIXME: magic #, is this always enough? */
            UCHAR buffer[256];
            int fromsize;
            struct sockaddr_in fromaddr;
            WORD respXID, flags, queryCount, answerCount;
            WSABUF wsaBuf = { sizeof(buffer), (CHAR*)buffer };
            DWORD bytesReceived, recvFlags = 0;

            fromsize = sizeof(fromaddr);
            r = WSARecvFrom(fd, &wsaBuf, 1, &bytesReceived, &recvFlags,
             (struct sockaddr*)&fromaddr, &fromsize, NULL, NULL);
            if(r < 0)
            {
                ret = NRC_SYSTEM;
                break;
            }

            if (bytesReceived < NBNS_HEADER_SIZE)
                continue;

            respXID = NBR_GETWORD(buffer);
            if (adapter->nameQueryXID != respXID)
                continue;

            flags = NBR_GETWORD(buffer + 2);
            queryCount = NBR_GETWORD(buffer + 4);
            answerCount = NBR_GETWORD(buffer + 6);

            /* a reply shouldn't contain a query, ignore bad packet */
            if (queryCount > 0)
                continue;

            if ((flags & NBNS_RESPONSE_AND_OPCODE) == NBNS_RESPONSE_AND_QUERY)
            {
                if ((flags & NBNS_REPLYCODE) != 0)
                    ret = NRC_NAMERR;
                else if ((flags & NBNS_REPLYCODE) == 0 && answerCount > 0)
                {
                    PUCHAR ptr = buffer + NBNS_HEADER_SIZE;
                    BOOL shouldContinue = TRUE;
                    WORD answerIndex = 0;

                    found = TRUE;
                    /* decode one answer at a time */
                    while (ret == NRC_GOODRET && answerIndex < answerCount &&
                     ptr - buffer < bytesReceived && shouldContinue)
                    {
                        WORD rLen;

                        /* scan past name */
                        for (; ptr[0] && ptr - buffer < bytesReceived; )
                            ptr += ptr[0] + 1;
                        ptr++;
                        ptr += 2; /* scan past type */
                        if (ptr - buffer < bytesReceived && ret == NRC_GOODRET
                         && NBR_GETWORD(ptr) == NBNS_CLASS_INTERNET)
                            ptr += sizeof(WORD);
                        else
                            ret = NRC_SYSTEM; /* parse error */
                        ptr += sizeof(DWORD); /* TTL */
                        rLen = NBR_GETWORD(ptr);
                        rLen = min(rLen, bytesReceived - (ptr - buffer));
                        ptr += sizeof(WORD);
                        shouldContinue = answerCallback(data, answerCount,
                         answerIndex, ptr, rLen);
                        ptr += rLen;
                        answerIndex++;
                    }
                }
            }
        }
    }
    TRACE("returning 0x%02x\n", ret);
    return ret;