ref: 2c6cc121339ade33ac5aa4b46356df1cd5469fbe
dir: /sys/src/cmd/ratfs/ctlfiles.c/
#include "ratfs.h"
#include <ip.h>
enum {
ACCEPT = 0, /* verbs in control file */
REFUSED,
DENIED,
DIALUP,
BLOCKED,
DELAY,
NONE,
Subchar = '#', /* character substituted for '/' in file names */
};
static Keyword actions[] = {
"allow", ACCEPT,
"accept", ACCEPT,
"block", BLOCKED,
"deny", DENIED,
"dial", DIALUP,
"relay", DELAY,
"delay", DELAY,
0, NONE,
};
static void acctinsert(Node*, char*);
static char* getline(Biobuf*);
static void ipinsert(Node*, char*);
static void ipsort(void);
/*
* Input the configuration file
* Currently we only process the "ournets"
* specification.
*/
void
getconf(void)
{
Biobuf *bp;
char *cp;
Node *np, *dir, **l;
if(debugfd >= 0)
fprint(debugfd, "loading %s\n", conffile);
bp = Bopen(conffile, OREAD);
if(bp == 0)
return;
dir = finddir(Trusted);
if(dir == 0)
return;
/*
* if this isn't the first time, purge permanent entries
*/
trustedqid = Qtrustedfile;
if(lastconftime){
l = &dir->children;
for(np = dir->children; np; np = *l){
if(np->d.type == Trustedperm){
*l = np->sibs;
free(np);
} else {
np->d.qid.path = trustedqid++;
l = &np->sibs;
}
}
dir->count = 0;
}
for(;;){
cp = getline(bp);
if(cp == 0)
break;
if (strcmp(cp, "ournets") == 0){
for(cp += strlen(cp)+1; cp && *cp; cp += strlen(cp)+1){
np = newnode(dir, cp, Trustedperm, 0111, trustedqid++);
cidrparse(&np->ip, cp);
subslash(cp);
np->d.name = atom(cp);
}
}
}
Bterm(bp);
lastconftime = time(0);
}
/*
* Reload the control file, if necessary
*/
void
reload(void)
{
int type, action;
Biobuf *bp;
char *cp;
Node *np, *dir;
if(debugfd >= 0)
fprint(debugfd,"loading %s\n", ctlfile);
bp = Bopen(ctlfile, OREAD);
if(bp == 0)
return;
if(lastctltime){
for(dir = root->children; dir; dir = dir->sibs){
if (dir->d.type != Addrdir)
continue;
for(np = dir->children; np; np = np->sibs)
np->count = 0;
}
}
for(;;){
cp = getline(bp);
if(cp == 0)
break;
type = *cp;
if(type == '*'){
cp++;
if(*cp == 0) /* space before keyword */
cp++;
}
action = findkey(cp, actions);
if (action == NONE)
continue;
if (action == ACCEPT)
dir = dirwalk("allow", root);
else
if (action == DELAY)
dir = dirwalk("delay", root);
else
dir = dirwalk(cp, root);
if(dir == 0)
continue;
for(cp += strlen(cp)+1; cp && *cp; cp += strlen(cp)+1){
if(type == '*')
acctinsert(dir, cp);
else
ipinsert(dir, cp);
}
}
Bterm(bp);
ipsort();
dummy.d.mtime = dummy.d.atime = lastctltime = time(0);
}
/*
* get a canonicalized line: a string of null-terminated lower-case
* tokens with a two null bytes at the end.
*/
static char*
getline(Biobuf *bp)
{
char c, *cp, *p, *q;
int n;
static char *buf;
static int bufsize;
for(;;){
cp = Brdline(bp, '\n');
if(cp == 0)
return 0;
n = Blinelen(bp);
cp[n-1] = 0;
if(buf == 0 || bufsize < n+1){
bufsize += 512;
if(bufsize < n+1)
bufsize = n+1;
buf = realloc(buf, bufsize);
if(buf == 0)
break;
}
q = buf;
for (p = cp; *p; p++){
c = *p;
if(c == '\\' && p[1]) /* we don't allow \<newline> */
c = *++p;
else
if(c == '#')
break;
else
if(c == ' ' || c == '\t' || c == ',')
if(q == buf || q[-1] == 0)
continue;
else
c = 0;
*q++ = tolower(c);
}
if(q != buf){
if(q[-1])
*q++ = 0;
*q = 0;
break;
}
}
return buf;
}
/*
* Match a keyword
*/
int
findkey(char *val, Keyword *p)
{
for(; p->name; p++)
if(strcmp(val, p->name) == 0)
break;
return p->code;
}
/*
* parse a cidr specification in either IP/mask or IP#mask format
*/
void
cidrparse(Cidraddr *cidr, char *cp)
{
char *p, *slash;
int c;
ulong a, m;
uchar addr[IPv4addrlen];
uchar mask[IPv4addrlen];
char buf[64];
/*
* find '/' or '#' character in the cidr specification
*/
slash = 0;
for(p = buf; p < buf+sizeof(buf)-1 && *cp; p++) {
c = *cp++;
switch(c) {
case Subchar:
c = '/';
slash = p;
break;
case '/':
slash = p;
break;
default:
break;
}
*p = c;
}
*p = 0;
v4parsecidr(addr, mask, buf);
a = nhgetl(addr);
m = nhgetl(mask);
/*
* if a mask isn't specified, we build a minimal mask
* instead of using the default mask for that net. in this
* case we never allow a class A mask (0xff000000).
*/
if(slash == 0){
m = 0xff000000;
p = buf;
for(p = strchr(p, '.'); p && p[1]; p = strchr(p+1, '.'))
m = (m>>8)|0xff000000;
/* force at least a class B */
m |= 0xffff0000;
}
cidr->ipaddr = a;
cidr->mask = m;
}
/*
* Substitute Subchar ('#') for '/'
*/
char*
subslash(char *os)
{
char *s;
for(s=os; *s; s++)
if(*s == '/')
*s = Subchar;
return os;
}
/*
* Insert an account pseudo-file in a directory
*/
static void
acctinsert(Node *np, char *cp)
{
int i;
char *tmp;
Address *ap;
static char *dangerous[] = { "*", "!", "*!", "!*", "*!*", 0 };
if(cp == 0 || *cp == 0)
return;
/* rule out dangerous patterns */
for (i = 0; dangerous[i]; i++)
if(strcmp(cp, dangerous[i])== 0)
return;
np = dirwalk("account", np);
if(np == 0)
return;
i = np->count++;
if(i >= np->allocated){
np->allocated = np->count;
np->addrs = realloc(np->addrs, np->allocated*sizeof(Address));
if(np->addrs == 0)
fatal("out of memory");
}
ap = &np->addrs[i]; /* new entry on end */
tmp = strdup(cp);
if(tmp == nil)
fatal("out of memory");
subslash(tmp);
ap->name = atom(tmp);
free(tmp);
}
/*
* Insert an IP address pseudo-file in a directory
*/
static void
ipinsert(Node *np, char *cp)
{
char *tmp;
int i;
Address *ap;
if(cp == 0 || *cp == 0)
return;
np = dirwalk("ip", np);
if(np == 0)
return;
i = np->count++;
if(i >= np->allocated){
np->allocated = np->count;
np->addrs = realloc(np->addrs, np->allocated*sizeof(Address));
if(np->addrs == 0)
fatal("out of memory");
}
ap = &np->addrs[i]; /* new entry on end */
tmp = strdup(cp);
if(tmp == nil)
fatal("out of memory");
subslash(tmp);
ap->name = atom(tmp);
free(tmp);
cidrparse(&ap->ip, cp);
}
int
ipcomp(void *a, void *b)
{
ulong aip, bip;
aip = ((Address*)a)->ip.ipaddr;
bip = ((Address*)b)->ip.ipaddr;
if(aip > bip)
return 1;
if(aip < bip)
return -1;
return 0;
}
/*
* Sort a directory of IP addresses
*/
static void
ipsort(void)
{
int base;
Node *dir, *np;
base = Qaddrfile;
for(dir = root->children; dir; dir = dir->sibs){
if (dir->d.type != Addrdir)
continue;
for(np = dir->children; np; np = np->sibs){
if(np->d.type == IPaddr && np->count && np->addrs)
qsort(np->addrs, np->count, sizeof(Address), ipcomp);
np->baseqid = base;
base += np->count;
}
}
}