/*      $NetBSD: rmpproto.c,v 1.16 2018/01/23 21:06:25 sevan Exp $      */

/*
* Copyright (c) 1988, 1992 The University of Utah and the Center
*      for Software Science (CSS).
* Copyright (c) 1992, 1993
*      The Regents of the University of California.  All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Center for Software Science of the University of Utah Computer
* Science Department.  CSS requests users of this software to return
* to [email protected] any improvements that they make and grant
* CSS redistribution rights.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*      from: @(#)rmpproto.c    8.1 (Berkeley) 6/4/93
*
* From: Utah Hdr: rmpproto.c 3.1 92/07/06
* Author: Jeff Forys, University of Utah CSS
*/

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)rmpproto.c  8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: rmpproto.c,v 1.16 2018/01/23 21:06:25 sevan Exp $");
#endif
#endif /* not lint */

#include <sys/param.h>
#include <sys/time.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "defs.h"

/*
**  ProcessPacket -- determine packet type and do what's required.
**
**      An RMP BOOT packet has been received.  Look at the type field
**      and process Boot Requests, Read Requests, and Boot Complete
**      packets.  Any other type will be dropped with a warning msg.
**
**      Parameters:
**              rconn - the new connection
**              client - list of files available to this host
**
**      Returns:
**              Nothing.
**
**      Side Effects:
**              - If this is a valid boot request, it will be added to
**                the linked list of outstanding requests (RmpConns).
**              - If this is a valid boot complete, its associated
**                entry in RmpConns will be deleted.
**              - Also, unless we run out of memory, a reply will be
**                sent to the host that sent the packet.
*/
void
ProcessPacket(RMPCONN *rconn, CLIENT *client)
{
       struct rmp_packet *rmp;
       RMPCONN *rconnout;

       rmp = &rconn->rmp;              /* cache pointer to RMP packet */

       switch(rmp->r_type) {           /* do what we came here to do */
               case RMP_BOOT_REQ:              /* boot request */
                       if ((rconnout = NewConn(rconn)) == NULL)
                               return;

                       /*
                        *  If the Session ID is 0xffff, this is a "probe"
                        *  packet and we do not want to add the connection
                        *  to the linked list of active connections.  There
                        *  are two types of probe packets, if the Sequence
                        *  Number is 0 they want to know our host name, o/w
                        *  they want the name of the file associated with
                        *  the number spec'd by the Sequence Number.
                        *
                        *  If this is an actual boot request, open the file
                        *  and send a reply.  If SendBootRepl() does not
                        *  return 0, add the connection to the linked list
                        *  of active connections, otherwise delete it since
                        *  an error was encountered.
                        */
                       if (ntohs(rmp->r_brq.rmp_session) == RMP_PROBESID) {
                               if (WORDZE(rmp->r_brq.rmp_seqno))
                                       (void) SendServerID(rconnout);
                               else
                                       (void) SendFileNo(rmp, rconnout,
                                                         client? client->files:
                                                                 BootFiles);
                               FreeConn(rconnout);
                       } else {
                               if (SendBootRepl(rmp, rconnout,
                                   client? client->files: BootFiles))
                                       AddConn(rconnout);
                               else
                                       FreeConn(rconnout);
                       }
                       break;

               case RMP_BOOT_REPL:             /* boot reply (not valid) */
                       syslog(LOG_WARNING, "%s: sent a boot reply",
                              EnetStr(rconn));
                       break;

               case RMP_READ_REQ:              /* read request */
                       /*
                        *  Send a portion of the boot file.
                        */
                       (void) SendReadRepl(rconn);
                       break;

               case RMP_READ_REPL:             /* read reply (not valid) */
                       syslog(LOG_WARNING, "%s: sent a read reply",
                              EnetStr(rconn));
                       break;

               case RMP_BOOT_DONE:             /* boot complete */
                       /*
                        *  Remove the entry from the linked list of active
                        *  connections.
                        */
                       (void) BootDone(rconn);
                       break;

               default:                        /* unknown RMP packet type */
                       syslog(LOG_WARNING, "%s: unknown packet type (%u)",
                              EnetStr(rconn), rmp->r_type);
       }
}

/*
**  SendServerID -- send our host name to who ever requested it.
**
**      Parameters:
**              rconn - the reply packet to be formatted.
**
**      Returns:
**              1 on success, 0 on failure.
**
**      Side Effects:
**              none.
*/
int
SendServerID(RMPCONN *rconn)
{
       struct rmp_packet *rpl;
       char *src, *dst;
       u_int8_t *size;

       rpl = &rconn->rmp;                      /* cache ptr to RMP packet */

       /*
        *  Set up assorted fields in reply packet.
        */
       rpl->r_brpl.rmp_type = RMP_BOOT_REPL;
       rpl->r_brpl.rmp_retcode = RMP_E_OKAY;
       ZEROWORD(rpl->r_brpl.rmp_seqno);
       rpl->r_brpl.rmp_session = 0;
       rpl->r_brpl.rmp_version = htons(RMP_VERSION);

       size = &rpl->r_brpl.rmp_flnmsize;       /* ptr to length of host name */

       /*
        *  Copy our host name into the reply packet incrementing the
        *  length as we go.  Stop at RMP_HOSTLEN or the first dot.
        */
       src = MyHost;
       dst = (char *) &rpl->r_brpl.rmp_flnm;
       for (*size = 0; *size < RMP_HOSTLEN; (*size)++) {
               if (*src == '.' || *src == '\0')
                       break;
               *dst++ = *src++;
       }

       rconn->rmplen = RMPBOOTSIZE(*size);     /* set packet length */

       return(SendPacket(rconn));              /* send packet */
}

/*
**  SendFileNo -- send the name of a bootable file to the requester.
**
**      Parameters:
**              req - RMP BOOT packet containing the request.
**              rconn - the reply packet to be formatted.
**              filelist - list of files available to the requester.
**
**      Returns:
**              1 on success, 0 on failure.
**
**      Side Effects:
**              none.
*/
int
SendFileNo(struct rmp_packet *req, RMPCONN *rconn, char *filelist[])
{
       struct rmp_packet *rpl;
       char *src, *dst;
       u_int8_t *size;
       int i;

       GETWORD(req->r_brpl.rmp_seqno, i);      /* SeqNo is really FileNo */
       rpl = &rconn->rmp;                      /* cache ptr to RMP packet */

       /*
        *  Set up assorted fields in reply packet.
        */
       rpl->r_brpl.rmp_type = RMP_BOOT_REPL;
       PUTWORD(i, rpl->r_brpl.rmp_seqno);
       i--;
       rpl->r_brpl.rmp_session = 0;
       rpl->r_brpl.rmp_version = htons(RMP_VERSION);

       size = &rpl->r_brpl.rmp_flnmsize;       /* ptr to length of filename */
       *size = 0;                              /* init length to zero */

       /*
        *  Copy the file name into the reply packet incrementing the
        *  length as we go.  Stop at end of string or when RMPBOOTDATA
        *  characters have been copied.  Also, set return code to
        *  indicate success or "no more files".
        */
       if (i < C_MAXFILE && filelist[i] != NULL) {
               src = filelist[i];
               dst = (char *)&rpl->r_brpl.rmp_flnm;
               for (; *src && *size < RMPBOOTDATA; (*size)++) {
                       if (*src == '\0')
                               break;
                       *dst++ = *src++;
               }
               rpl->r_brpl.rmp_retcode = RMP_E_OKAY;
       } else
               rpl->r_brpl.rmp_retcode = RMP_E_NODFLT;

       rconn->rmplen = RMPBOOTSIZE(*size);     /* set packet length */

       return(SendPacket(rconn));              /* send packet */
}

/*
**  SendBootRepl -- open boot file and respond to boot request.
**
**      Parameters:
**              req - RMP BOOT packet containing the request.
**              rconn - the reply packet to be formatted.
**              filelist - list of files available to the requester.
**
**      Returns:
**              1 on success, 0 on failure.
**
**      Side Effects:
**              none.
*/
int
SendBootRepl(struct rmp_packet *req, RMPCONN *rconn, char *filelist[])
{
       int retval;
       char *filename, filepath[RMPBOOTDATA+1];
       RMPCONN *oldconn;
       struct rmp_packet *rpl;
       char *src, *dst1, *dst2;
       u_int8_t i;

       /*
        *  If another connection already exists, delete it since we
        *  are obviously starting again.
        */
       if ((oldconn = FindConn(rconn)) != NULL) {
               syslog(LOG_WARNING, "%s: dropping existing connection",
                      EnetStr(oldconn));
               RemoveConn(oldconn);
       }

       rpl = &rconn->rmp;                      /* cache ptr to RMP packet */

       /*
        *  Set up assorted fields in reply packet.
        */
       rpl->r_brpl.rmp_type = RMP_BOOT_REPL;
       COPYWORD(req->r_brq.rmp_seqno, rpl->r_brpl.rmp_seqno);
       rpl->r_brpl.rmp_session = htons(GenSessID());
       rpl->r_brpl.rmp_version = htons(RMP_VERSION);
       rpl->r_brpl.rmp_flnmsize = req->r_brq.rmp_flnmsize;

       /*
        *  Copy file name to `filepath' string, and into reply packet.
        */
       dst1 = filepath;
       dst2 = &rpl->r_brpl.rmp_flnm;
       if (req->r_brq.rmp_flnmsize)
               src = &req->r_brq.rmp_flnm;
       else {
               /* no file supplied, substitute the first one */
               src = filelist[0];
               req->r_brq.rmp_flnmsize = strlen(src);
       }
       for (i = 0; i < req->r_brq.rmp_flnmsize; i++)
               *dst1++ = *dst2++ = *src++;
       *dst1 = '\0';

       /*
        *  If we are booting HP-UX machines, their secondary loader will
        *  ask for files like "/hp-ux".  As a security measure, we do not
        *  allow boot files to lay outside the boot directory (unless they
        *  are purposely link'd out.  So, make `filename' become the path-
        *  stripped file name and spoof the client into thinking that it
        *  really got what it wanted.
        */
       if ((filename = strrchr(filepath,'/')) != NULL)
               filename++;
       else
               filename = filepath;

       /*
        *  Check that this is a valid boot file name.
        */
       for (i = 0; i < C_MAXFILE && filelist[i] != NULL; i++)
               if (STREQN(filename, filelist[i]))
                       goto match;

       /*
        *  Invalid boot file name, set error and send reply packet.
        */
       rpl->r_brpl.rmp_retcode = RMP_E_NOFILE;
       retval = 0;
       goto sendpkt;

match:
       /*
        *  This is a valid boot file.  Open the file and save the file
        *  descriptor associated with this connection and set success
        *  indication.  If the file couldnt be opened, set error:
        *      "no such file or dir" - RMP_E_NOFILE
        *      "file table overflow" - RMP_E_BUSY
        *      "too many open files" - RMP_E_BUSY
        *      anything else         - RMP_E_OPENFILE
        */
       if ((rconn->bootfd = open(filename, O_RDONLY, 0600)) < 0) {
               rpl->r_brpl.rmp_retcode = (errno == ENOENT)? RMP_E_NOFILE:
                       (errno == EMFILE || errno == ENFILE)? RMP_E_BUSY:
                       RMP_E_OPENFILE;
               retval = 0;
       } else {
               rpl->r_brpl.rmp_retcode = RMP_E_OKAY;
               retval = 1;
       }

sendpkt:
       syslog(LOG_INFO, "%s: request to boot %s (%s)",
              EnetStr(rconn), filename, retval? "granted": "denied");

       rconn->rmplen = RMPBOOTSIZE(rpl->r_brpl.rmp_flnmsize);

       return (retval & SendPacket(rconn));
}

/*
**  SendReadRepl -- send a portion of the boot file to the requester.
**
**      Parameters:
**              rconn - the reply packet to be formatted.
**
**      Returns:
**              1 on success, 0 on failure.
**
**      Side Effects:
**              none.
*/
int
SendReadRepl(RMPCONN *rconn)
{
       int retval = 0;
       RMPCONN *oldconn;
       struct rmp_packet *rpl, *req;
       int size = 0;
       int madeconn = 0;

       /*
        *  Find the old connection.  If one doesnt exist, create one only
        *  to return the error code.
        */
       if ((oldconn = FindConn(rconn)) == NULL) {
               if ((oldconn = NewConn(rconn)) == NULL)
                       return(0);
               syslog(LOG_ERR, "SendReadRepl: no active connection (%s)",
                      EnetStr(rconn));
               madeconn++;
       }

       req = &rconn->rmp;              /* cache ptr to request packet */
       rpl = &oldconn->rmp;            /* cache ptr to reply packet */

       if (madeconn) {                 /* no active connection above; abort */
               rpl->r_rrpl.rmp_retcode = RMP_E_ABORT;
               retval = 1;
               goto sendpkt;
       }

       /*
        *  Make sure Session ID's match.
        */
       if (ntohs(req->r_rrq.rmp_session) !=
           ((rpl->r_type == RMP_BOOT_REPL)? ntohs(rpl->r_brpl.rmp_session):
                                            ntohs(rpl->r_rrpl.rmp_session))) {
               syslog(LOG_ERR, "SendReadRepl: bad session id (%s)",
                      EnetStr(rconn));
               rpl->r_rrpl.rmp_retcode = RMP_E_BADSID;
               retval = 1;
               goto sendpkt;
       }

       /*
        *  If the requester asks for more data than we can fit,
        *  silently clamp the request size down to RMPREADDATA.
        *
        *  N.B. I do not know if this is "legal", however it seems
        *  to work.  This is necessary for bpfwrite() on machines
        *  with MCLBYTES less than 1514.
        */
       if (ntohs(req->r_rrq.rmp_size) > RMPREADDATA)
               req->r_rrq.rmp_size = htons(RMPREADDATA);

       /*
        *  Position read head on file according to info in request packet.
        */
       GETWORD(req->r_rrq.rmp_offset, size);
       if (lseek(oldconn->bootfd, (off_t)size, SEEK_SET) < 0) {
               syslog(LOG_ERR, "SendReadRepl: lseek: %m (%s)",
                      EnetStr(rconn));
               rpl->r_rrpl.rmp_retcode = RMP_E_ABORT;
               retval = 1;
               goto sendpkt;
       }

       /*
        *  Read data directly into reply packet.
        */
       if ((size = read(oldconn->bootfd, &rpl->r_rrpl.rmp_data,
                        (int) ntohs(req->r_rrq.rmp_size))) <= 0) {
               if (size < 0) {
                       syslog(LOG_ERR, "SendReadRepl: read: %m (%s)",
                              EnetStr(rconn));
                       rpl->r_rrpl.rmp_retcode = RMP_E_ABORT;
               } else {
                       rpl->r_rrpl.rmp_retcode = RMP_E_EOF;
               }
               retval = 1;
               goto sendpkt;
       }

       /*
        *  Set success indication.
        */
       rpl->r_rrpl.rmp_retcode = RMP_E_OKAY;

sendpkt:
       /*
        *  Set up assorted fields in reply packet.
        */
       rpl->r_rrpl.rmp_type = RMP_READ_REPL;
       COPYWORD(req->r_rrq.rmp_offset, rpl->r_rrpl.rmp_offset);
       rpl->r_rrpl.rmp_session = req->r_rrq.rmp_session;

       oldconn->rmplen = RMPREADSIZE(size);    /* set size of packet */

       retval &= SendPacket(oldconn);          /* send packet */

       if (madeconn)                           /* clean up after ourself */
               FreeConn(oldconn);

       return (retval);
}

/*
**  BootDone -- free up memory allocated for a connection.
**
**      Parameters:
**              rconn - incoming boot complete packet.
**
**      Returns:
**              1 on success, 0 on failure.
**
**      Side Effects:
**              none.
*/
int
BootDone(RMPCONN *rconn)
{
       RMPCONN *oldconn;
       struct rmp_packet *rpl;

       /*
        *  If we cant find the connection, ignore the request.
        */
       if ((oldconn = FindConn(rconn)) == NULL) {
               syslog(LOG_ERR, "BootDone: no existing connection (%s)",
                      EnetStr(rconn));
               return(0);
       }

       rpl = &oldconn->rmp;                    /* cache ptr to RMP packet */

       /*
        *  Make sure Session ID's match.
        */
       if (ntohs(rconn->rmp.r_rrq.rmp_session) !=
           ((rpl->r_type == RMP_BOOT_REPL)? ntohs(rpl->r_brpl.rmp_session):
                                           ntohs(rpl->r_rrpl.rmp_session))) {
               syslog(LOG_ERR, "BootDone: bad session id (%s)",
                      EnetStr(rconn));
               return(0);
       }

       RemoveConn(oldconn);                    /* remove connection */

       syslog(LOG_INFO, "%s: boot complete", EnetStr(rconn));

       return(1);
}

/*
**  SendPacket -- send an RMP packet to a remote host.
**
**      Parameters:
**              rconn - packet to be sent.
**
**      Returns:
**              1 on success, 0 on failure.
**
**      Side Effects:
**              none.
*/
int
SendPacket(RMPCONN *rconn)
{
       /*
        *  Set Ethernet Destination address to Source (BPF and the enet
        *  driver will take care of getting our source address set).
        */
       memmove((char *)&rconn->rmp.hp_hdr.daddr[0],
           (char *)&rconn->rmp.hp_hdr.saddr[0], RMP_ADDRLEN);
       rconn->rmp.hp_hdr.len = htons(rconn->rmplen - sizeof(struct hp_hdr));

       /*
        *  Reverse 802.2/HP Extended Source & Destination Access Pts.
        */
       rconn->rmp.hp_llc.dxsap = htons(HPEXT_SXSAP);
       rconn->rmp.hp_llc.sxsap = htons(HPEXT_DXSAP);

       /*
        *  Last time this connection was active.
        */
       (void) gettimeofday(&rconn->tstamp, (struct timezone *)0);

       if (DbgFp != NULL)                      /* display packet */
               DispPkt(rconn,DIR_SENT);

       /*
        *  Send RMP packet to remote host.
        */
       return(BpfWrite(rconn));
}