4.3BSD/usr/src/ucb/Mail/optim.c
/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
#ifndef lint
static char *sccsid = "@(#)optim.c 5.5 (Berkeley) 11/2/85";
#endif not lint
/*
* Mail -- a program for sending and receiving mail.
*
* Network name modification routines.
*/
#include "rcv.h"
#include "configdefs.h"
#include <ctype.h>
/*
* Map a name into the correct network "view" of the
* name. This is done by prepending the name with the
* network address of the sender, then optimizing away
* nonsense.
*/
char *
netmap(name, from)
char name[], from[];
{
char nbuf[BUFSIZ], ret[BUFSIZ];
register char *cp;
if (strlen(from) == 0)
return(name);
if (any('@', name) || any('%', name))
return(savestr(arpafix(name, from)));
cp = revarpa(from);
if (cp == NOSTR)
return(name);
strcpy(nbuf, cp);
cp = &nbuf[strlen(nbuf) - 1];
while (!any(*cp, metanet) && cp > nbuf)
cp--;
if (cp == nbuf)
return(name);
*++cp = 0;
strcat(nbuf, revarpa(name));
optim(nbuf, ret);
cp = revarpa(ret);
if (!icequal(name, cp))
return(savestr(cp));
return(name);
}
/*
* Rename the given network path to use
* the kinds of names that we would right here.
*/
char *
rename(str)
char str[];
{
register char *cp, *cp2;
char buf[BUFSIZ], path[BUFSIZ];
register int c, host;
cp = str;
strcpy(path, "");
for (;;) {
if ((c = *cp++) == 0)
break;
cp2 = buf;
while (!any(c, metanet) && c != 0) {
*cp2++ = c;
c = *cp++;
}
*cp2 = 0;
if (c == 0) {
strcat(path, buf);
break;
}
host = netlook(buf, ntype(c));
strcat(path, netname(host));
stradd(path, c);
}
if (strcmp(str, path) != 0)
return(savestr(path));
return(str);
}
/*
* Turn a network machine name into a unique character
*/
netlook(machine, attnet)
char machine[];
{
register struct netmach *np;
register char *cp, *cp2;
char nbuf[BUFSIZ];
/*
* Make into lower case.
*/
for (cp = machine, cp2 = nbuf; *cp; *cp2++ = little(*cp++))
if (cp2 >= &nbuf[sizeof(nbuf)-1])
break;
*cp2 = 0;
/*
* If a single letter machine, look through those first.
*/
if (strlen(nbuf) == 1)
for (np = netmach; np->nt_mid != 0; np++)
if (np->nt_mid == nbuf[0])
return(nbuf[0]);
/*
* Look for usual name
*/
for (np = netmach; np->nt_mid != 0; np++)
if (strcmp(np->nt_machine, nbuf) == 0)
return(np->nt_mid);
/*
* Look in side hash table.
*/
return(mstash(nbuf, attnet));
}
/*
* Make a little character.
*/
little(c)
register int c;
{
if (c >= 'A' && c <= 'Z')
c += 'a' - 'A';
return(c);
}
/*
* Turn a network unique character identifier into a network name.
*/
char *
netname(mid)
{
register struct netmach *np;
char *mlook();
if (mid & 0200)
return(mlook(mid));
for (np = netmach; np->nt_mid != 0; np++)
if (np->nt_mid == mid)
return(np->nt_machine);
return(NOSTR);
}
/*
* Deal with arpa net addresses. The way this is done is strange.
* In particular, if the destination arpa net host is not Berkeley,
* then the address is correct as stands. Otherwise, we strip off
* the trailing @Berkeley, then cook up a phony person for it to
* be from and optimize the result.
*/
char *
arpafix(name, from)
char name[];
char from[];
{
register char *cp;
register int arpamach;
char newname[BUFSIZ];
char fake[5];
char fakepath[20];
if (debug) {
fprintf(stderr, "arpafix(%s, %s)\n", name, from);
}
cp = rindex(name, '@');
if (cp == NOSTR)
cp = rindex(name, '%');
if (cp == NOSTR) {
fprintf(stderr, "Somethings amiss -- no @ or % in arpafix\n");
return(name);
}
cp++;
arpamach = netlook(cp, '@');
if (arpamach == 0) {
if (debug)
fprintf(stderr, "machine %s unknown, uses: %s\n", cp, name);
return(name);
}
if (((nettype(arpamach) & nettype(LOCAL)) & ~AN) == 0) {
if (debug)
fprintf(stderr, "machine %s known but remote, uses: %s\n",
cp, name);
return(name);
}
strcpy(newname, name);
cp = rindex(newname, '@');
if (cp == NOSTR)
cp = rindex(newname, '%');
*cp = 0;
fake[0] = arpamach;
fake[1] = ':';
fake[2] = LOCAL;
fake[3] = ':';
fake[4] = 0;
prefer(fake);
strcpy(fakepath, netname(fake[0]));
stradd(fakepath, fake[1]);
strcat(fakepath, "daemon");
if (debug)
fprintf(stderr, "machine local, call netmap(%s, %s)\n",
newname, fakepath);
return(netmap(newname, fakepath));
}
/*
* Take a network machine descriptor and find the types of connected
* nets and return it.
*/
nettype(mid)
{
register struct netmach *np;
if (mid & 0200)
return(mtype(mid));
for (np = netmach; np->nt_mid != 0; np++)
if (np->nt_mid == mid)
return(np->nt_type);
return(0);
}
/*
* Hashing routines to salt away machines seen scanning
* networks paths that we don't know about.
*/
#define XHSIZE 19 /* Size of extra hash table */
#define NXMID (XHSIZE*3/4) /* Max extra machines */
struct xtrahash {
char *xh_name; /* Name of machine */
short xh_mid; /* Machine ID */
short xh_attnet; /* Attached networks */
} xtrahash[XHSIZE];
struct xtrahash *xtab[XHSIZE]; /* F: mid-->machine name */
short midfree; /* Next free machine id */
/*
* Initialize the extra host hash table.
* Called by sreset.
*/
minit()
{
register struct xtrahash *xp, **tp;
register int i;
midfree = 0;
tp = &xtab[0];
for (xp = &xtrahash[0]; xp < &xtrahash[XHSIZE]; xp++) {
xp->xh_name = NOSTR;
xp->xh_mid = 0;
xp->xh_attnet = 0;
*tp++ = (struct xtrahash *) 0;
}
}
/*
* Stash a net name in the extra host hash table.
* If a new entry is put in the hash table, deduce what
* net the machine is attached to from the net character.
*
* If the machine is already known, add the given attached
* net to those already known.
*/
mstash(name, attnet)
char name[];
{
register struct xtrahash *xp;
struct xtrahash *xlocate();
int x;
xp = xlocate(name);
if (xp == (struct xtrahash *) 0) {
printf("Ran out of machine id spots\n");
return(0);
}
if (xp->xh_name == NOSTR) {
if (midfree >= XHSIZE) {
printf("Out of machine ids\n");
return(0);
}
xtab[midfree] = xp;
xp->xh_name = savestr(name);
xp->xh_mid = 0200 + midfree++;
}
x = ntype(attnet);
if (x == 0)
xp->xh_attnet |= SN;
else
xp->xh_attnet |= x;
return(xp->xh_mid);
}
/*
* Search for the given name in the hash table
* and return the pointer to it if found, or to the first
* empty slot if not found.
*
* If no free slots can be found, return 0.
*/
struct xtrahash *
xlocate(name)
char name[];
{
register int h, q, i;
register char *cp;
register struct xtrahash *xp;
for (h = 0, cp = name; *cp; h = (h << 2) + *cp++)
;
if (h < 0 && (h = -h) < 0)
h = 0;
h = h % XHSIZE;
cp = name;
for (i = 0, q = 0; q < XHSIZE; i++, q = i * i) {
xp = &xtrahash[(h + q) % XHSIZE];
if (xp->xh_name == NOSTR)
return(xp);
if (strcmp(cp, xp->xh_name) == 0)
return(xp);
if (h - q < 0)
h += XHSIZE;
xp = &xtrahash[(h - q) % XHSIZE];
if (xp->xh_name == NOSTR)
return(xp);
if (strcmp(cp, xp->xh_name) == 0)
return(xp);
}
return((struct xtrahash *) 0);
}
/*
* Return the name from the extra host hash table corresponding
* to the passed machine id.
*/
char *
mlook(mid)
{
register int m;
if ((mid & 0200) == 0)
return(NOSTR);
m = mid & 0177;
if (m >= midfree) {
printf("Use made of undefined machine id\n");
return(NOSTR);
}
return(xtab[m]->xh_name);
}
/*
* Return the bit mask of net's that the given extra host machine
* id has so far.
*/
mtype(mid)
{
register int m;
if ((mid & 0200) == 0)
return(0);
m = mid & 0177;
if (m >= midfree) {
printf("Use made of undefined machine id\n");
return(0);
}
return(xtab[m]->xh_attnet);
}
/*
* Take a network name and optimize it. This gloriously messy
* operation takes place as follows: the name with machine names
* in it is tokenized by mapping each machine name into a single
* character machine id (netlook). The separator characters (network
* metacharacters) are left intact. The last component of the network
* name is stripped off and assumed to be the destination user name --
* it does not participate in the optimization. As an example, the
* name "research!vax135!research!ucbvax!bill" becomes, tokenized,
* "r!x!r!v!" and "bill" A low level routine, optim1, fixes up the
* network part (eg, "r!x!r!v!"), then we convert back to network
* machine names and tack the user name on the end.
*
* The result of this is copied into the parameter "name"
*/
optim(net, name)
char net[], name[];
{
char netcomp[BUFSIZ], netstr[40], xfstr[40];
register char *cp, *cp2;
register int c;
strcpy(netstr, "");
cp = net;
for (;;) {
/*
* Rip off next path component into netcomp
*/
cp2 = netcomp;
while (*cp && !any(*cp, metanet))
*cp2++ = *cp++;
*cp2 = 0;
/*
* If we hit null byte, then we just scanned
* the destination user name. Go off and optimize
* if its so.
*/
if (*cp == 0)
break;
if ((c = netlook(netcomp, *cp)) == 0) {
printf("No host named \"%s\"\n", netcomp);
err:
strcpy(name, net);
return;
}
stradd(netstr, c);
stradd(netstr, *cp++);
/*
* If multiple network separators given,
* throw away the extras.
*/
while (any(*cp, metanet))
cp++;
}
if (strlen(netcomp) == 0) {
printf("net name syntax\n");
goto err;
}
optim1(netstr, xfstr);
/*
* Convert back to machine names.
*/
cp = xfstr;
strcpy(name, "");
while (*cp) {
if ((cp2 = netname(*cp++)) == NOSTR) {
printf("Made up bad net name\n");
printf("Machine code %c (0%o)\n", cp[-1], cp[-1]);
printf("Sorry -- dumping now. Alert K. Shoens\n");
core(0);
goto err;
}
strcat(name, cp2);
stradd(name, *cp++);
}
strcat(name, netcomp);
}
/*
* Take a string of network machine id's and separators and
* optimize them. We process these by pulling off maximal
* leading strings of the same type, passing these to the appropriate
* optimizer and concatenating the results.
*/
optim1(netstr, name)
char netstr[], name[];
{
char path[40], rpath[40];
register char *cp, *cp2;
register int tp, nc;
cp = netstr;
prefer(cp);
strcpy(name, "");
/*
* If the address ultimately points back to us,
* just return a null network path.
*/
if (strlen(cp) > 1 && cp[strlen(cp) - 2] == LOCAL)
return;
while (*cp != 0) {
strcpy(path, "");
tp = ntype(cp[1]);
nc = cp[1];
while (*cp && tp == ntype(cp[1])) {
stradd(path, *cp++);
cp++;
}
switch (netkind(tp)) {
default:
strcpy(rpath, path);
break;
case IMPLICIT:
optimimp(path, rpath);
break;
case EXPLICIT:
optimex(path, rpath);
break;
}
for (cp2 = rpath; *cp2 != 0; cp2++) {
stradd(name, *cp2);
stradd(name, nc);
}
}
optiboth(name);
prefer(name);
}
/*
* Return the network of the separator --
* AN for arpa net
* BN for Bell labs net
* SN for Schmidt (berkeley net)
* 0 if we don't know.
*/
ntype(nc)
register int nc;
{
register struct ntypetab *np;
for (np = ntypetab; np->nt_char != 0; np++)
if (np->nt_char == nc)
return(np->nt_bcode);
return(0);
}
/*
* Return the kind of routing used for the particular net
* EXPLICIT means explicitly routed
* IMPLICIT means implicitly routed
* 0 means don't know
*/
netkind(nt)
register int nt;
{
register struct nkindtab *np;
for (np = nkindtab; np->nk_type != 0; np++)
if (np->nk_type == nt)
return(np->nk_kind);
return(0);
}
/*
* Do name optimization for an explicitly routed network (eg BTL network).
*/
optimex(net, name)
char net[], name[];
{
register char *cp, *rp;
register int m;
char *rindex();
strcpy(name, net);
cp = name;
if (strlen(cp) == 0)
return(-1);
if (cp[strlen(cp)-1] == LOCAL) {
name[0] = 0;
return(0);
}
for (cp = name; *cp; cp++) {
m = *cp;
rp = rindex(cp+1, m);
if (rp != NOSTR)
strcpy(cp, rp);
}
return(0);
}
/*
* Do name optimization for implicitly routed network (eg, arpanet,
* Berkeley network)
*/
optimimp(net, name)
char net[], name[];
{
register char *cp;
register int m;
cp = net;
if (strlen(cp) == 0)
return(-1);
m = cp[strlen(cp) - 1];
if (m == LOCAL) {
strcpy(name, "");
return(0);
}
name[0] = m;
name[1] = 0;
return(0);
}
/*
* Perform global optimization on the given network path.
* The trick here is to look ahead to see if there are any loops
* in the path and remove them. The interpretation of loops is
* more strict here than in optimex since both the machine and net
* type must match.
*/
optiboth(net)
char net[];
{
register char *cp, *cp2;
char *rpair();
cp = net;
if (strlen(cp) == 0)
return;
if ((strlen(cp) % 2) != 0) {
printf("Strange arg to optiboth\n");
return;
}
while (*cp) {
cp2 = rpair(cp+2, *cp);
if (cp2 != NOSTR)
strcpy(cp, cp2);
cp += 2;
}
}
/*
* Find the rightmost instance of the given (machine, type) pair.
*/
char *
rpair(str, mach)
char str[];
{
register char *cp, *last;
cp = str;
last = NOSTR;
while (*cp) {
if (*cp == mach)
last = cp;
cp += 2;
}
return(last);
}
/*
* Change the network separators in the given network path
* to the preferred network transmission means.
*/
prefer(name)
char name[];
{
register char *cp;
register int state, n;
state = LOCAL;
for (cp = name; *cp; cp += 2) {
n = best(state, *cp);
if (n)
cp[1] = n;
state = *cp;
}
}
/*
* Return the best network separator for the given machine pair.
*/
best(src, dest)
{
register int dtype, stype;
register struct netorder *np;
stype = nettype(src);
dtype = nettype(dest);
fflush(stdout);
if (stype == 0 || dtype == 0) {
printf("ERROR: unknown internal machine id\n");
return(0);
}
if ((stype & dtype) == 0)
return(0);
np = &netorder[0];
while ((np->no_stat & stype & dtype) == 0)
np++;
return(np->no_char);
}
#ifdef GETHOST
/*
* Initialize the network name of the current host.
*/
inithost()
{
register struct netmach *np;
static char host[64];
gethostname(host, sizeof host);
for (np = netmach; np->nt_machine != 0; np++)
if (strcmp(np->nt_machine, EMPTY) == 0)
break;
if (np->nt_machine == 0) {
printf("Cannot find empty slot for dynamic host entry\n");
exit(1);
}
np->nt_machine = host;
}
#endif GETHOST
/*
* Code to twist around arpa net names.
*/
#define WORD 257 /* Token for a string */
static char netbuf[256];
static char *yylval;
/*
* Reverse all of the arpa net addresses in the given name to
* be of the form "host @ user" instead of "user @ host"
* This function is its own inverse.
*/
char *
revarpa(str)
char str[];
{
if (yyinit(str) < 0)
return(NOSTR);
if (name())
return(NOSTR);
if (strcmp(str, netbuf) == 0)
return(str);
return(savestr(netbuf));
}
/*
* Parse (by recursive descent) network names, using the following grammar:
* name:
* term {':' term}
* term {'^' term}
* term {'!' term}
* term '@' name
* term '%' name
*
* term:
* string of characters.
*/
name()
{
register int t;
register char *cp;
for (;;) {
t = yylex();
if (t != WORD)
return(-1);
cp = yylval;
t = yylex();
switch (t) {
case 0:
strcat(netbuf, cp);
return(0);
case '@':
case '%':
if (name())
return(-1);
stradd(netbuf, '@');
strcat(netbuf, cp);
return(0);
case WORD:
return(-1);
default:
strcat(netbuf, cp);
stradd(netbuf, t);
}
}
}
/*
* Scanner for network names.
*/
static char *charp; /* Current input pointer */
static int nexttok; /* Salted away next token */
/*
* Initialize the network name scanner.
*/
yyinit(str)
char str[];
{
static char lexbuf[BUFSIZ];
netbuf[0] = 0;
if (strlen(str) >= sizeof lexbuf - 1)
return(-1);
nexttok = 0;
strcpy(lexbuf, str);
charp = lexbuf;
return(0);
}
/*
* Scan and return a single token.
* yylval is set to point to a scanned string.
*/
yylex()
{
register char *cp, *dot;
register int s;
if (nexttok) {
s = nexttok;
nexttok = 0;
return(s);
}
cp = charp;
while (*cp && isspace(*cp))
cp++;
if (*cp == 0)
return(0);
if (any(*cp, metanet)) {
charp = cp+1;
return(*cp);
}
dot = cp;
while (*cp && !any(*cp, metanet) && !any(*cp, " \t"))
cp++;
if (any(*cp, metanet))
nexttok = *cp;
if (*cp == 0)
charp = cp;
else
charp = cp+1;
*cp = 0;
yylval = dot;
return(WORD);
}
/*
* Add a single character onto a string.
*/
stradd(str, c)
register char *str;
register int c;
{
str += strlen(str);
*str++ = c;
*str = 0;
}