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kermit.c
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kermit.c
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#define KERMIT_C
/*
Embedded Kermit protocol module
Version: 1.6
Most Recent Update: Wed Mar 30 12:39:11 2011
No stdio or other runtime library calls, no system calls, no system
includes, no static data, and no global variables in this module.
Warning: you can't use debug() in any routine whose argument list
does not include "struct k_data * k". Thus most routines in this
module include this arg, even if they don't use it.
Author: Frank da Cruz.
As of version 1.6 of 30 March 2011, E-Kermit is Open Source software under
the Revised 3-Clause BSD license which follows. E-Kermit 1.6 is identical
to version 1.51 except for the new license.
Author: Frank da Cruz.
Copyright (C) 1995, 2011,
Trustees of Columbia University in the City of New York.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* 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.
* Neither the name of Columbia 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
*/
#include "cdefs.h" /* C language defs for all modules */
#include "debug.h" /* Debugging */
#include "kermit.h" /* Kermit protocol definitions */
#define zgetc() \
((--(k->zincnt))>=0)?((int)(*(k->zinptr)++)&0xff):(*(k->readf))(k)
/* See cdefs.h for meaning of STATIC, ULONG, and UCHAR */
STATIC ULONG stringnum(UCHAR *, struct k_data *);
STATIC UCHAR * numstring(ULONG, UCHAR *, int, struct k_data *);
int STATIC spkt(char, short, int, UCHAR *, struct k_data *);
int STATIC ack(struct k_data *, short, UCHAR * text);
int STATIC nak(struct k_data *, short, short);
int STATIC chk1(UCHAR *, struct k_data *);
STATIC USHORT chk2(UCHAR *, struct k_data *);
#ifdef F_CRC
STATIC USHORT chk3(UCHAR *, struct k_data *);
#endif /* F_CRC */
void STATIC spar(struct k_data *, UCHAR *, int);
int STATIC rpar(struct k_data *, char);
int STATIC decode(struct k_data *, struct k_response *, short, UCHAR *);
#ifdef F_AT
int STATIC gattr(struct k_data *, UCHAR *, struct k_response *);
int STATIC sattr(struct k_data *, struct k_response *);
#endif /* F_AT */
#ifndef RECVONLY
int STATIC sdata(struct k_data *, struct k_response *);
#endif /* RECVONLY */
void STATIC epkt(char *, struct k_data *);
int STATIC getpkt(struct k_data *, struct k_response *);
int STATIC encstr(UCHAR *, struct k_data *, struct k_response *);
void STATIC decstr(UCHAR *, struct k_data *, struct k_response *);
void STATIC encode(int, int, struct k_data *);
int STATIC nxtpkt(struct k_data *);
int STATIC resend(struct k_data *);
#ifdef DEBUG
int xerror(void);
#endif /* DEBUG */
int /* The kermit() function */
kermit(short f, /* Function code */
struct k_data *k, /* The control struct */
short r_slot, /* Received packet slot number */
int len, /* Length of packet in slot */
char *msg, /* Message for error packet */
struct k_response *r) { /* Response struct */
int i, j, rc; /* Workers */
int datalen; /* Length of packet data field */
int bctu; /* Block check type for this packet */
UCHAR *p; /* Pointer to packet data field */
UCHAR *q; /* Pointer to data to be checked */
UCHAR *s; /* Worker string pointer */
UCHAR c, t; /* Worker chars */
UCHAR pbc[4]; /* Copy of packet block check */
short seq, prev; /* Copies of sequence numbers */
short chklen; /* Length of packet block check */
#ifdef F_CRC
unsigned int crc; /* 16-bit CRC */
#endif /* F_CRC */
int ok;
debug(DB_MSG,"----------",0,0); /* Marks each entry */
debug(DB_LOG,"f",0,f);
debug(DB_LOG,"state",0,k->state);
debug(DB_LOG,"zincnt",0,(k->zincnt));
if (f == K_INIT) { /* Initialize packet buffers etc */
k->version = (UCHAR *)VERSION; /* Version of this module */
r->filename[0] = '\0'; /* No filename yet. */
r->filedate[0] = '\0'; /* No filedate yet. */
r->filesize = 0L; /* No filesize yet. */
r->sofar = 0L; /* No bytes transferred yet */
for (i = 0; i < P_WSLOTS; i++) { /* Packet info for each window slot */
freerslot(k,i);
freesslot(k,i);
}
#ifdef F_TSW
for (i = 0; i < 64; i++) { /* Packet finder array */
k->r_pw[i] = -1; /* initialized to "no packets yet" */
k->s_pw[i] = -1; /* initialized to "no packets yet" */
}
#endif /* F_TSW */
/* Initialize the k_data structure */
for (i = 0; i < 6; i++)
k->s_remain[i] = '\0';
k->state = R_WAIT; /* Beginning protocol state */
r->status = R_WAIT;
k->what = W_RECV; /* Default action */
k->s_first = 1; /* Beginning of file */
k->r_soh = k->s_soh = SOH; /* Packet start */
k->r_eom = k->s_eom = CR; /* Packet end */
k->s_seq = k->r_seq = 0; /* Packet sequence number */
k->s_type = k->r_type = 0; /* Packet type */
k->r_timo = P_R_TIMO; /* Timeout interval for me to use */
k->s_timo = P_S_TIMO; /* Timeout for other Kermit to use */
k->r_maxlen = P_PKTLEN; /* Maximum packet length */
k->s_maxlen = P_PKTLEN; /* Maximum packet length */
k->window = P_WSLOTS; /* Maximum window slots */
k->wslots = 1; /* Current window slots */
k->zincnt = 0;
k->dummy = 0;
k->filename = (UCHAR *)0;
/* Parity must be filled in by the caller */
k->retry = P_RETRY; /* Retransmission limit */
k->s_ctlq = k->r_ctlq = '#'; /* Control prefix */
k->ebq = 'Y'; /* 8th-bit prefix negotiation */
k->ebqflg = 0; /* 8th-bit prefixing flag */
k->rptq = '~'; /* Send repeat prefix */
k->rptflg = 0; /* Repeat counts negotiated */
k->s_rpt = 0; /* Current repeat count */
k->capas = 0 /* Capabilities */
#ifdef F_LP
| CAP_LP /* Long packets */
#endif /* F_LP */
#ifdef F_SW
| CAP_SW /* Sliding windows */
#endif /* F_SW */
#ifdef F_AT
| CAP_AT /* Attribute packets */
#endif /* F_AT */
;
k->opktbuf[0] = '\0'; /* No packets sent yet. */
k->opktlen = 0;
#ifdef F_CRC
/* This is the only way to initialize these tables -- no static data. */
k->crcta[ 0] = 0; /* CRC generation table A */
k->crcta[ 1] = 010201;
k->crcta[ 2] = 020402;
k->crcta[ 3] = 030603;
k->crcta[ 4] = 041004;
k->crcta[ 5] = 051205;
k->crcta[ 6] = 061406;
k->crcta[ 7] = 071607;
k->crcta[ 8] = 0102010;
k->crcta[ 9] = 0112211;
k->crcta[10] = 0122412;
k->crcta[11] = 0132613;
k->crcta[12] = 0143014,
k->crcta[13] = 0153215;
k->crcta[14] = 0163416;
k->crcta[15] = 0173617;
k->crctb[ 0] = 0; /* CRC table B */
k->crctb[ 1] = 010611;
k->crctb[ 2] = 021422;
k->crctb[ 3] = 031233;
k->crctb[ 4] = 043044;
k->crctb[ 5] = 053655;
k->crctb[ 6] = 062466;
k->crctb[ 7] = 072277;
k->crctb[ 8] = 0106110;
k->crctb[ 9] = 0116701;
k->crctb[10] = 0127532;
k->crctb[11] = 0137323;
k->crctb[12] = 0145154;
k->crctb[13] = 0155745;
k->crctb[14] = 0164576;
k->crctb[15] = 0174367;
#endif /* F_CRC */
return(X_OK);
#ifndef RECVONLY
} else if (f == K_SEND) {
if (rpar(k,'S') != X_OK) /* Send S packet with my parameters */
return(X_ERROR); /* I/O error, quit. */
k->state = S_INIT; /* All OK, switch states */
r->status = S_INIT;
k->what = W_SEND; /* Act like a sender */
return(X_OK);
#endif /* RECVONLY */
} else if (f == K_STATUS) { /* Status report requested. */
return(X_STATUS); /* File name, date, size, if any. */
} else if (f == K_QUIT) { /* You told me to quit */
return(X_DONE); /* so I quit. */
} else if (f == K_ERROR) { /* Send an error packet... */
epkt(msg,k);
k->closef(k,0,(k->state == S_DATA) ? 1 : 2); /* Close file */
return(X_DONE); /* and quit. */
} else if (f != K_RUN) { /* Anything else is an error. */
return(X_ERROR);
}
if (k->state == R_NONE) /* (probably unnecessary) */
return(X_OK);
/* If we're in the protocol, check to make sure we got a new packet */
debug(DB_LOG,"r_slot",0,r_slot);
debug(DB_LOG,"len",0,len);
if (r_slot < 0) /* We should have a slot here */
return(K_ERROR);
else
k->ipktinfo[r_slot].len = len; /* Copy packet length to ipktinfo. */
if (len < 4) { /* Packet obviously no good? */
#ifdef RECVONLY
return(nak(k,k->r_seq,r_slot)); /* Send NAK for the packet we want */
#else
if (k->what == W_RECV) /* If receiving */
return(nak(k,k->r_seq,r_slot)); /* Send NAK for the packet we want */
else /* If sending */
return(resend(k)); /* retransmit last packet. */
#endif /* RECVONLY */
}
/* Parse the packet */
if (k->what == W_RECV) { /* If we're sending ACKs */
switch(k->cancel) { /* Get cancellation code if any */
case 0: s = (UCHAR *)0; break;
case 1: s = (UCHAR *)"X"; break;
case 2: s = (UCHAR *)"Z"; break;
}
}
p = &(k->ipktbuf[0][r_slot]); /* Point to it */
q = p; /* Pointer to data to be checked */
k->ipktinfo[r_slot].len = xunchar(*p++); /* Length field */
seq = k->ipktinfo[r_slot].seq = xunchar(*p++); /* Sequence number */
t = k->ipktinfo[r_slot].typ = *p++; /* Type */
if (
#ifndef RECVONLY
(k->what == W_RECV) && /* Echo (it happens), ignore */
#endif /* RECVONLY */
(t == 'N' || t == 'Y')) {
freerslot(k,r_slot);
return(X_OK);
}
k->ipktinfo[r_slot].dat = p; /* Data field, maybe */
#ifdef F_LP
if (k->ipktinfo[r_slot].len == 0) { /* Length 0 means long packet */
c = p[2]; /* Get header checksum */
p[2] = '\0';
if (xunchar(c) != chk1(p-3,k)) { /* Check it */
freerslot(k,r_slot); /* Bad */
debug(DB_MSG,"HDR CHKSUM BAD",0,0);
#ifdef RECVONLY
return(nak(k,k->r_seq,r_slot)); /* Send NAK */
#else
if (k->what == W_RECV)
return(nak(k,k->r_seq,r_slot)); /* Send NAK */
else
return(resend(k));
#endif /* RECVONLY */
}
debug(DB_MSG,"HDR CHKSUM OK",0,0);
p[2] = c; /* Put checksum back */
datalen = xunchar(p[0])*95 + xunchar(p[1]) - k->bct; /* Data length */
p += 3; /* Fix data pointer */
k->ipktinfo[r_slot].dat = p; /* Permanent record of data pointer */
} else { /* Regular packet */
#endif /* F_LP */
datalen = k->ipktinfo[r_slot].len - k->bct - 2; /* Data length */
#ifdef F_LP
}
#endif /* F_LP */
#ifdef F_CRC
if (t == 'S' || k->state == S_INIT) { /* S-packet was retransmitted? */
chklen = 1; /* Block check is always type 1 */
datalen = k->ipktinfo[r_slot].len - 3; /* Data length */
} else {
chklen = k->bct;
}
#else
chklen = 1; /* Block check is always type 1 */
datalen = k->ipktinfo[r_slot].len - 3; /* Data length */
#endif /* F_CRC */
debug(DB_LOG,"bct",0,(k->bct));
debug(DB_LOG,"datalen",0,datalen);
debug(DB_LOG,"chkalen",0,chklen);
#ifdef F_CRC
for (i = 0; i < chklen; i++) /* Copy the block check */
pbc[i] = p[datalen+i];
pbc[i] = '\0'; /* Null-terminate block check string */
#else
pbc[0] = p[datalen];
pbc[1] = '\0';
#endif /* F_CRC */
p[datalen] = '\0'; /* and the packet DATA field. */
#ifdef F_CRC
switch (chklen) { /* Check the block check */
case 1: /* Type 1, 6-bit checksum */
#endif /* F_CRC */
ok = (xunchar(*pbc) == chk1(q,k));
#ifdef DEBUG
if (ok && xerror()) ok = 0;
#endif /* DEBUG */
if (!ok) {
freerslot(k,r_slot);
#ifdef RECVONLY
nak(k,k->r_seq,r_slot);
#else
if (k->what == W_RECV)
nak(k,k->r_seq,r_slot);
else
resend(k);
#endif /* RECVONLY */
return(X_OK);
}
#ifdef F_CRC
break;
case 2: /* Type 2, 12-bit checksum */
i = xunchar(*pbc) << 6 | xunchar(pbc[1]);
ok = (i == chk2(q,k));
#ifdef DEBUG
if (ok && xerror()) ok = 0;
#endif /* DEBUG */
if (!ok) { /* No match */
if (t == 'E') { /* Allow E packets to have type 1 */
int j;
j = datalen;
p[j++] = pbc[0];
p[j] = '\0';
if (xunchar(pbc[1]) == chk1(q,k))
break;
else
p[--j] = '\0';
}
freerslot(k,r_slot);
#ifdef RECVONLY
nak(k,k->r_seq,r_slot);
#else
if (k->what == W_RECV)
nak(k,k->r_seq,r_slot);
else
resend(k);
#endif /* RECVONLY */
return(X_OK);
}
break;
case 3: /* Type 3, 16-bit CRC */
crc = (xunchar(pbc[0]) << 12)
| (xunchar(pbc[1]) << 6)
| (xunchar(pbc[2]));
ok = (crc == chk3(q,k));
#ifdef DEBUG
if (ok && xerror()) {
ok = 0;
debug(DB_MSG,"CRC ERROR INJECTED",0,0);
}
#endif /* DEBUG */
if (!ok) {
debug(DB_LOG,"CRC ERROR t",0,t);
if (t == 'E') { /* Allow E packets to have type 1 */
int j;
j = datalen;
p[j++] = pbc[0];
p[j++] = pbc[1];
p[j] = '\0';
if (xunchar(pbc[2]) == chk1(q,k))
break;
else { j -=2; p[j] = '\0'; }
}
freerslot(k,r_slot);
#ifdef RECVONLY
nak(k,k->r_seq,r_slot);
#else
if (k->what == W_RECV)
nak(k,k->r_seq,r_slot);
else
resend(k);
#endif /* RECVONLY */
return(X_OK);
}
}
#endif /* F_CRC */
if (t == 'E') /* (AND CLOSE FILES?) */
return(X_ERROR);
prev = k->r_seq - 1; /* Get sequence of previous packet */
if (prev < 0)
prev = 63;
debug(DB_LOG,"Seq",0,seq);
debug(DB_LOG,"Prev",0,prev);
if (seq == k->r_seq) { /* Is this the packet we want? */
k->ipktinfo[r_slot].rtr = 0; /* Yes */
} else {
freerslot(k,r_slot); /* No, discard it. */
if (seq == prev) { /* If it's the previous packet again */
debug(DB_LOG,"PREVIOUS PKT RETRIES",0,
(long)(k->ipktinfo[r_slot].rtr));
if (k->ipktinfo[r_slot].rtr++ > k->retry) { /* Count retries */
epkt("Too many retries", k); /* Too may */
return(X_ERROR); /* Give up */
} else { /* Otherwise */
return(resend(k)); /* Send old outbound packet buffer */
}
#ifdef RECVONLY
} else {
return(nak(k,k->r_seq,r_slot));
#else
} else if (k->what == W_RECV) { /* Otherwise NAK the one we want */
return(nak(k,k->r_seq,r_slot));
} else { /* or whatever... */
return(resend(k));
#endif /* RECVONLY */
}
}
#ifndef RECVONLY
if (k->what == W_SEND) { /* Sending, check for ACK */
if (t != 'Y') { /* Not an ACK */
debug(DB_LOG,"t!=Y t",0,t);
freerslot(k,r_slot); /* added 2004-06-30 -- JHD */
return(resend(k));
}
if (k->state == S_DATA) { /* ACK to Data packet?*/
if (k->cancel || /* Cancellation requested by caller? */
*p == 'X' || *p == 'Z') { /* Or by receiver? */
k->closef(k,*p,1); /* Close input file*/
nxtpkt(k); /* Next packet sequence number */
if ((rc = spkt('Z',k->s_seq,0,(UCHAR *)0,k)) != X_OK)
return(rc);
if (*p == 'Z' || k->cancel == I_GROUP) { /* Cancel Group? */
debug(DB_MSG,"Group Cancel (Send)",0,0);
while (*(k->filelist)) { /* Go to end of file list */
debug(DB_LOG,"Skip",*(k->filelist),0);
(k->filelist)++;
}
}
k->state = S_EOF; /* Wait for ACK to EOF */
r->status = S_EOF;
k->r_seq = k->s_seq; /* Sequence number of packet we want */
return(X_OK);
}
}
freerslot(k,r_slot); /* It is, free the ACK. */
}
#endif /* RECVONLY */
/* Now we have an incoming packet with the expected sequence number. */
debug(DB_CHR,"Packet OK",0,t);
debug(DB_LOG,"State",0,k->state);
switch (k->state) { /* Kermit protocol state switcher */
#ifndef RECVONLY
case S_INIT: /* Got other Kermit's parameters */
case S_EOF: /* Got ACK to EOF packet */
nxtpkt(k); /* Get next packet number etc */
if (k->state == S_INIT) { /* Got ACK to S packet? */
spar(k,p,datalen); /* Set negotiated parameters */
debug(DB_CHR,"Parity",0,k->parity);
debug(DB_LOG,"Ebqflg",0,(k->ebqflg));
debug(DB_CHR,"Ebq",0,(k->ebq));
}
k->filename = *(k->filelist); /* Get next filename */
if (k->filename) { /* If there is one */
int i;
for (i = 0; i < FN_MAX; i++) { /* Copy name to result struct */
r->filename[i] = k->filename[i];
if (!(r->filename[i]))
break;
}
(k->filelist)++;
debug(DB_LOG,"Filename",k->filename,0);
if ((rc = (k->openf)(k,k->filename,1)) != X_OK) /* Try to open */
return(rc);
encstr(k->filename,k,r); /* Encode the name for transmission */
if ((rc = spkt('F',k->s_seq,-1,k->xdata,k)) != X_OK)
return(rc); /* Send F packet */
r->sofar = 0L;
k->state = S_FILE; /* Wait for ACK */
r->status = S_FILE;
} else { /* No more files - we're done */
if ((rc = spkt('B',k->s_seq,0,(UCHAR *)0,k)) != X_OK)
return(rc); /* Send EOT packet */
k->state = S_EOT; /* Wait for ACK */
r->status = S_EOT;
}
k->r_seq = k->s_seq; /* Sequence number of packet we want */
return(X_OK); /* Return to control program */
case S_FILE: /* Got ACK to F packet */
nxtpkt(k); /* Get next packet number etc */
#ifdef F_AT
if (k->capas & CAP_AT) { /* A-packets negotiated? */
if ((rc = sattr(k,r)) != X_OK) /* Yes, send Attribute packet */
return(rc);
k->state = S_ATTR; /* And wait for its ACK */
r->status = S_ATTR;
} else
#endif /* F_AT */
if (sdata(k,r) == 0) { /* No A packets - send first data */
/* File is empty so send EOF packet */
if ((rc = spkt('Z',k->s_seq,0,(UCHAR *)0,k)) != X_OK)
return(rc);
k->closef(k,*p,1); /* Close input file*/
k->state = S_EOF; /* Wait for ACK to EOF */
r->status = S_EOF;
} else { /* Sent some data */
k->state = S_DATA; /* Wait for ACK to first data */
r->status = S_DATA;
}
k->r_seq = k->s_seq; /* Sequence number to wait for */
return(X_OK);
case S_ATTR: /* Got ACK to A packet */
case S_DATA: /* Got ACK to D packet */
nxtpkt(k); /* Get next packet number */
if (k->state == S_ATTR) {
/* CHECK ATTRIBUTE RESPONSE */
/* IF REJECTED do the right thing... */
k->state = S_DATA;
r->status = S_DATA;
}
rc = sdata(k,r); /* Send first or next data packet */
debug(DB_LOG,"Seq",0,(k->s_seq));
debug(DB_LOG,"sdata()",0,rc);
if (rc == 0) { /* If there was no data to send */
if ((rc = spkt('Z',k->s_seq,0,(UCHAR *)0,k)) != X_OK)
return(rc); /* Send EOF */
k->closef(k,*p,1); /* Close input file*/
k->state = S_EOF; /* And wait for ACK */
r->status = S_EOF;
} /* Otherwise stay in data state */
k->r_seq = k->s_seq; /* Sequence number to wait for */
return(X_OK);
case S_EOT: /* Get ACK to EOT packet */
return(X_DONE); /* (or X_ERROR) */
#endif /* RECVONLY */
case R_WAIT: /* Waiting for the S packet */
if (t == 'S') { /* Got it */
spar(k,p,datalen); /* Set parameters from it */
rc = rpar(k,'Y'); /* ACK with my parameters */
debug(DB_LOG,"rpar rc",0,rc);
if (rc != X_OK)
return(X_ERROR); /* I/O error, quit. */
k->state = R_FILE; /* All OK, switch states */
r->status = R_FILE;
} else { /* Wrong kind of packet, send NAK */
epkt("Unexpected packet type",k);
rc = X_ERROR;
}
freerslot(k,r_slot); /* Free packet slot */
return(rc);
case R_FILE: /* Want an F or B packet */
if (t == 'F') { /* File name */
if ((rc = decode(k, r, 0, p)) == X_OK) /* Decode and save */
k->state = R_ATTR; /* Switch to next state */
r->status = k->state;
debug(DB_LOG,"R_FILE decode rc",0,rc);
debug(DB_LOG,"R_FILE FILENAME",r->filename,0);
if (rc == X_OK) { /* All OK so far */
r->filedate[0] = '\0'; /* No file date yet */
r->filesize = 0L; /* Or file size */
r->sofar = 0L; /* Or bytes transferred yet */
rc = ack(k, k->r_seq, r->filename); /* so ACK the F packet */
} else {
epkt("Filename error",k); /* Error decoding filename */
}
} else if (t == 'B') { /* Break, end of transaction */
freerslot(k,r_slot);
rc = (ack(k, k->r_seq, (UCHAR *)0) == X_OK) ? X_DONE : X_ERROR;
} else {
epkt("Unexpected packet type",k);
rc = X_ERROR;
}
freerslot(k,r_slot);
return(rc);
case R_ATTR: /* Want A, D, or Z packet */
#ifdef F_AT
if (t == 'A') { /* Attribute packet */
int x;
x = gattr(k, p, r); /* Read the attributes */
if (x > -1)
k->binary = x;
freerslot(k,r_slot);
ack(k, k->r_seq, (UCHAR *) "Y"); /* Always accept the file */
return(X_OK);
} else
#endif /* F_AT */
if (t == 'D') { /* First data packet */
k->obufpos = 0; /* Initialize output buffer */
k->filename = r->filename;
r->sofar = 0L;
if ((rc = (*(k->openf))(k,r->filename, 2)) == X_OK) {
k->state = R_DATA; /* Switch to Data state */
r->status = k->state;
rc = decode(k, r, 1, p); /* Write out first data packet */
freerslot(k,r_slot);
} else {
epkt("File refused or can't be opened", k);
freerslot(k,r_slot);
return(rc);
}
if (rc == X_OK)
rc = ack(k, k->r_seq, s);
else
epkt("Error writing data", k);
return(rc);
} else if (t == 'Z') { /* Empty file */
debug(DB_LOG,"R_ATTR empty file",r->filename,0);
k->obufpos = 0; /* Initialize output buffer */
k->filename = r->filename;
r->sofar = 0L; /* Open and close the file */
if ((rc = (*(k->openf))(k,r->filename, 2)) == X_OK) {
if (((rc = (*(k->closef))(k,*p,2)) == X_OK)) {
k->state = R_FILE;
rc = ack(k, k->r_seq, s);
} else {
epkt("Error closing empty file", k);
freerslot(k,r_slot);
return(rc);
}
} else {
epkt("File refused or can't be opened", k);
freerslot(k,r_slot);
return(rc);
}
r->status = k->state;
freerslot(k,r_slot);
} else {
epkt("Unexpected packet type",k);
return(X_ERROR);
}
break;
case R_DATA: /* Want a D or Z packet */
debug(DB_CHR,"R_DATA t",0,t);
if (t == 'D') { /* Data */
rc = decode(k, r, 1, p); /* Decode it */
freerslot(k,r_slot);
} else if (t == 'Z') { /* End of file */
debug(DB_CHR,"R_DATA",0,t);
if (k->obufpos > 0) { /* Flush output buffer */
rc = (*(k->writef))(k,k->obuf,k->obufpos);
debug(DB_LOG,"R_DATA writef rc",0,rc);
r->sofar += k->obufpos;
k->obufpos = 0;
}
if (((rc = (*(k->closef))(k,*p,2)) == X_OK) && (rc == X_OK))
k->state = R_FILE;
debug(DB_LOG,"R_DATA closef rc",0,rc);
r->status = k->state;
freerslot(k,r_slot);
} else {
epkt("Unexpected packet type",k);
return(X_ERROR);
}
if (rc == X_OK)
rc = ack(k, k->r_seq, s);
else
epkt(t == 'Z' ? "Can't close file" : "Error writing data",k);
return(rc);
case R_ERROR: /* Canceled from above */
default:
epkt(msg,k);
return(X_ERROR);
}
return(X_ERROR);
}
/* Utility routines */
UCHAR *
getrslot(struct k_data *k, short *n) { /* Find a free packet buffer */
register int i;
/*
Note: We don't clear the retry count here.
It is cleared only after the NEXT packet arrives, which
indicates that the other Kermit got our ACK for THIS packet.
*/
for (i = 0; i < P_WSLOTS; i++) { /* Search */
if (k->ipktinfo[i].len < 1) {
*n = i; /* Slot number */
k->ipktinfo[i].len = -1; /* Mark it as allocated but not used */
k->ipktinfo[i].seq = -1;
k->ipktinfo[i].typ = SP;
/* k->ipktinfo[i].rtr = 0; */ /* (see comment above) */
k->ipktinfo[i].dat = (UCHAR *)0;
return(&(k->ipktbuf[0][i]));
}
}
*n = -1;
return((UCHAR *)0);
}
void /* Initialize a window slot */
freerslot(struct k_data *k, short n) {
k->ipktinfo[n].len = 0; /* Packet length */
#ifdef COMMENT
k->ipktinfo[n].seq = 0; /* Sequence number */
k->ipktinfo[n].typ = (char)0; /* Type */
k->ipktinfo[n].rtr = 0; /* Retry count */
k->ipktinfo[n].flg = 0; /* Flags */
#endif /* COMMENT */
}
UCHAR *
getsslot(struct k_data *k, short *n) { /* Find a free packet buffer */
#ifdef COMMENT
register int i;
for (i = 0; i < P_WSLOTS; i++) { /* Search */
if (k->opktinfo[i].len < 1) {
*n = i; /* Slot number */
k->opktinfo[i].len = -1; /* Mark it as allocated but not used */
k->opktinfo[i].seq = -1;
k->opktinfo[i].typ = SP;
k->opktinfo[i].rtr = 0;
k->opktinfo[i].dat = (UCHAR *)0;
return(&(k->opktbuf[0][i]));
}
}
*n = -1;
return((UCHAR *)0);
#else
*n = 0;
return(k->opktbuf);
#endif /* COMMENT */
}
void /* Initialize a window slot */
freesslot(struct k_data * k, short n) {
k->opktinfo[n].len = 0; /* Packet length */
k->opktinfo[n].seq = 0; /* Sequence number */
k->opktinfo[n].typ = (char)0; /* Type */
k->opktinfo[n].rtr = 0; /* Retry count */
k->opktinfo[n].flg = 0; /* Flags */
}
/* C H K 1 -- Compute a type-1 Kermit 6-bit checksum. */
STATIC int
chk1(UCHAR *pkt, struct k_data * k) {
register unsigned int chk;
chk = chk2(pkt,k);
chk = (((chk & 0300) >> 6) + chk) & 077;
return((int) chk);
}
/* C H K 2 -- Numeric sum of all the bytes in the packet, 12 bits. */
STATIC USHORT
chk2(UCHAR *pkt,struct k_data * k) {
register USHORT chk;
for (chk = 0; *pkt != '\0'; pkt++)
chk += *pkt;
return(chk);
}
#ifdef F_CRC
/* C H K 3 -- Compute a type-3 Kermit block check. */
/*
Calculate the 16-bit CRC-CCITT of a null-terminated string using a lookup
table. Assumes the argument string contains no embedded nulls.
*/
STATIC USHORT
chk3(UCHAR *pkt, struct k_data * k) {
register USHORT c, crc;
for (crc = 0; *pkt != '\0'; pkt++) {
#ifdef COMMENT
c = crc ^ (long)(*pkt);
crc = (crc >> 8) ^ (k->crcta[(c & 0xF0) >> 4] ^ k->crctb[c & 0x0F]);
#else
c = crc ^ (*pkt);
crc = (crc >> 8) ^ ((k->crcta[(c & 0xF0) >> 4]) ^ (k->crctb[c & 0x0F]));
#endif /* COMMENT */
}
return(crc);
}
#endif /* F_CRC */
/* S P K T -- Send a packet. */
/*
Call with packet type, sequence number, data length, data, Kermit struct.
Returns:
X_OK on success
X_ERROR on i/o error
*/
STATIC int
spkt(char typ, short seq, int len, UCHAR * data, struct k_data * k) {
unsigned int crc; /* For building CRC */
int i, j, lenpos, m, n, x; /* Workers */
UCHAR * s, * buf;
debug(DB_LOG,"spkt len 1",0,len);
if (len < 0) { /* Calculate data length ourselves? */
len = 0;
s = data;
while (*s++) len++;
}
debug(DB_LOG,"spkt len 2",0,len);
buf = k->opktbuf; /* Where to put packet (FOR NOW) */
i = 0; /* Packet buffer position */
buf[i++] = k->s_soh; /* SOH */
lenpos = i++; /* Remember this place */
buf[i++] = tochar(seq); /* Sequence number */
buf[i++] = typ; /* Packet type */
j = len + k->bct;
#ifdef F_LP
if ((len + k->bct + 2) > 94) { /* If long packet */
buf[lenpos] = tochar(0); /* Put blank in LEN field */
buf[i++] = tochar(j / 95); /* Make extended header: Big part */
buf[i++] = tochar(j % 95); /* and small part of length. */
buf[i] = NUL; /* Terminate for header checksum */
buf[i++] = tochar(chk1(&buf[lenpos],k)); /* Insert header checksum */
} else { /* Short packet */
#endif /* F_LP */
buf[lenpos] = tochar(j+2); /* Single-byte length in LEN field */
#ifdef F_LP
}
#endif /* F_LP */
if (data) /* Copy data, if any */
for ( ; len--; i++)
buf[i] = *data++;
buf[i] = '\0';
#ifdef F_CRC
switch (k->bct) { /* Add block check */
case 1: /* 1 = 6-bit chksum */
buf[i++] = tochar(chk1(&buf[lenpos],k));
break;
case 2: /* 2 = 12-bit chksum */
j = chk2(&buf[lenpos],k);
#ifdef XAC
/* HiTech's XAC compiler silently ruins the regular code. */
/* An intermediate variable provides a work-around. */
/* 2004-06-29 -- JHD */
{
USHORT jj;
jj = (j >> 6) & 077; buf[i++] = tochar(jj);
jj = j & 077; buf[i++] = tochar(jj);
}
#else
buf[i++] = (unsigned)tochar((j >> 6) & 077);
buf[i++] = (unsigned)tochar(j & 077);
#endif /* XAC */
break;
case 3: /* 3 = 16-bit CRC */
crc = chk3(&buf[lenpos],k);
#ifdef XAC
/* HiTech's XAC compiler silently ruins the above code. */
/* An intermediate variable provides a work-around. */
/* 2004-06-29 -- JHD */
{
USHORT jj;
jj = (crc >> 12) & 0x0f; buf[i++] = tochar(jj);
jj = (crc >> 6) & 0x3f; buf[i++] = tochar(jj);
jj = crc & 0x3f; buf[i++] = tochar(jj);
}
#else
buf[i++] = (unsigned)tochar(((crc & 0170000)) >> 12);
buf[i++] = (unsigned)tochar((crc >> 6) & 077);
buf[i++] = (unsigned)tochar(crc & 077);
#endif /* XAC */
break;
}
#else
buf[i++] = tochar(chk1(&buf[lenpos],k));
#endif /* F_CRC */
buf[i++] = k->s_eom; /* Packet terminator */
buf[i] = '\0'; /* String terminator */
k->s_seq = seq; /* Remember sequence number */
k->opktlen = i; /* Remember length for retransmit */
#ifdef DEBUG
/* CORRUPT THE PACKET SENT BUT NOT THE ONE WE SAVE */
if (xerror()) {
UCHAR p[P_PKTLEN+8];
int i;
for (i = 0; i < P_PKTLEN; i++)
if (!(p[i] = buf[i]))
break;
p[i-2] = 'X';
debug(DB_PKT,"XPKT",(char *)&p[1],0);
return((*(k->txd))(k,p,k->opktlen)); /* Send it. */
}
debug(DB_PKT,"SPKT",(char *)&buf[1],0);
#endif /* DEBUG */
return((*(k->txd))(k,buf,k->opktlen)); /* Send it. */
}
/* N A K -- Send a NAK (negative acknowledgement) */
STATIC int
nak(struct k_data * k, short seq, short slot) {
int rc;
rc = spkt('N', seq, 0, (UCHAR *)0, k);
if (k->ipktinfo[slot].rtr++ > k->retry)
rc = X_ERROR;
return(rc);
}
/* A C K -- Send an ACK (positive acknowledgement) */
STATIC int
ack(struct k_data * k, short seq, UCHAR * text) {
int len, rc;
len = 0;
if (text) { /* Get length of data */
UCHAR *p;
p = text;
for ( ; *p++; len++) ;
}
rc = spkt('Y', seq, len, text, k); /* Send the packet */
debug(DB_LOG,"ack spkt rc",0,rc);
if (rc == X_OK) /* If OK */
k->r_seq = (k->r_seq + 1) % 64; /* bump the packet number */
return(rc);
}
/* S P A R -- Set parameters requested by other Kermit */
STATIC void
spar(struct k_data * k, UCHAR *s, int datalen) {
int x, y;
UCHAR c;
s--; /* Line up with field numbers. */