/*
- * userv service (or standalone program)
- * for per-user IP subranges.
+ * userv service (or standalone program) for per-user IP subranges.
+ *
+ * When invoked appropriately, it creates a point-to-point network
+ * interface with specified parameters. It arranges for packets sent out
+ * via that interface by the kernel to appear on its own stdout in SLIP or
+ * CSLIP encoding, and packets injected into its own stdin to be given to
+ * the kernel as if received on that interface. Optionally, additional
+ * routes can be set up to arrange for traffic for other address ranges to
+ * be routed through the new interface.
+ *
+ * This is the service program, which is invoked as root from userv (or may
+ * be invoked firectly).
+ *
+ * Its arguments are supposed to be, in order, as follows:
+ *
+ * The first two arguments are usually supplied by the userv
+ * configuration. See the file `ipif/ipif' in the source tree, which
+ * is installed in /etc/userv/services.d/ipif by `make install':
*
- * This is invoked as root, directly from userv.
- * Its arguments are supposed to be, in order:
* <config>
- * Specifies address ranges and gids which own them.
- * -- Indicates that the remaining arguments are user-supplied
- * and therefore untrusted.
+ *
+ * Specifies address ranges and gids which own them. The default
+ * configuration supplies /etc/userv/ipif-networks, which is then read
+ * for a list of entries, one per line.
+ *
+ * --
+ * Serves to separate the user-supplied and therefore untrusted
+ * arguments from the trusted first argument.
+ *
+ * The remaining arguments are supplied by the (untrusted) caller:
+ *
* <local-addr>,<peer-addr>,<mtu>,<proto>
+ *
* As for slattach. Supported protocols are slip, cslip, and
- * adaptive. Alternatively, set to `debug' to print debugging
- * info. <local-addr> is address of the interface on chiark;
- * <peer-addr> is the address of the point-to-point peer.
+ * adaptive. Alternatively, set to `debug' to print debugging info
+ * and exit. <local-addr> is address of the interface to be created
+ * on the local system; <peer-addr> is the address of the
+ * point-to-point peer. They must be actual addresses (not
+ * hostnames).
+ *
* <prefix>/<mask>,<prefix>/<mask>,...
- * List of additional routes to add for this interface.
- * May be the empty argument.
*
- * <config> is either
- * <gid>,<prefix>/<len>[,<junk>]
- * indicating that that gid may allocate addresses in
- * the relevant subspace (<junk> is ignored)
- * or #...
- * which is a comment
- * or /<config-file-name> or ./<config-file-name> or ../<config-file-name>
- * which refers to a file which contains lines which
- * are each <config>
- * or *
- * which means that anything is permitted
- *
- * Should be run from userv with no-disconnect-hup.
+ * List of additional routes to add for this interface. routes will
+ * be set up on the local system arranging for packets for those
+ * networks to be sent via the created interface. <prefix> must be an
+ * IPv4 address, and mask must be an integer (dotted-quad masks are
+ * not supported). If no additional routes are to be set up, use `-'
+ * or supply an empty argument.
+ *
+ * Each <config> item - whether a line file such as
+ * /etc/userv/ipif-networks, or supplied on the service program
+ * command line - is one of:
+ *
+ * /<config-file-name>
+ * ./<config-file-name>
+ * ../<config-file-name>
+ *
+ * Reads a file which contains lines which are each <config>
+ * items.
+ *
+ * <gid>,[=][-|+]<prefix>/<len>(-|+<prefix>/<len>...)[,<junk>]
+ *
+ * Indicates that <gid> may allocate addresses in the relevant address
+ * range (<junk> is ignored). <gid> must be numeric. To specify a
+ * single host address, you must specify a mask of /32. If `=' is
+ * specified then the specific subrange is only allowed for the local
+ * endpoint address, but not for remote addresses.
+ *
+ * More than one range may be given, with each range prefixed
+ * by + or -. In this case each address range in the rule will
+ * scanned in order, and the first range in the rule that matches
+ * any desired rule will count: if that first matching range is
+ * prefixed by `+' (or nothing) then the rule applies, if it
+ * is prefixed by `-' (or nothing matches), the rule does not.
+ *
+ * *
+ * Means that anything is to be permitted. This should not appear in
+ * /etc/userv/ipif-networks, as that would permit any user on the
+ * system to create any interfaces with any addresses and routes
+ * attached. It is provided so that root can usefully invoke the ipif
+ * service program directly (not via userv), without needing to set up
+ * permissions in /etc/userv/ipif-networks.
+ *
+ * #...
+ *
+ * Comment. Blank lines are also ignored.
+ *
+ * NB: Permission is granted if _any_ config entry matches the request.
+ *
+ * The service program should be run from userv with no-disconnect-hup.
+ */
+/*
+ * Copyright (C) 1999-2000,2003 Ian Jackson
+ * This file is part of ipif, part of userv-utils
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with userv-utils; if not, write to the Free Software
+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * $Id$
*/
#include <stdio.h>
#include <sys/stat.h>
#define NARGS 4
-#define MAXEXROUTES 5
-#define ATXTLEN 12
+#define MAXEXROUTES 50
+#define ATXTLEN 16
static const unsigned long gidmaxval= (unsigned long)((gid_t)-2);
static const char *const protos_ok[]= { "slip", "cslip", "adaptive", 0 };
static const char *configstr, *proto;
static unsigned long localaddr, peeraddr, mtu;
+static int localpming, peerpming;
static int localallow, peerallow, allallow;
static int nexroutes;
static struct exroute {
unsigned long prefix, mask;
- int allow;
+ int allow, pming;
char prefixtxt[ATXTLEN], masktxt[ATXTLEN];
} exroutes[MAXEXROUTES];
char *ep;
int endchar;
- if (!*argp) { badusage("missing number %s\n",what); }
+ if (!*argp) { badusage("missing number %s",what); }
rv= strtoul(*argp,&ep,0);
if ((endchar= *ep)) {
- if (!endchars) badusage("junk after number %s\n",what);
+ if (!endchars) badusage("junk after number %s",what);
if (!strchr(endchars,endchar))
badusage("invalid character or delimiter `%c' in or after number, %s:"
- " expected %s (or none?)\n", endchar,what,endchars);
+ " expected %s (or none?)", endchar,what,endchars);
*argp= ep+1;
} else {
*argp= 0;
return rv;
}
-static void addrnet_mustdiffer(const char *w1, unsigned long p1, unsigned long m1,
- const char *w2, unsigned long p2, unsigned long m2) {
+static int addrnet_overlap(unsigned long p1, unsigned long m1,
+ unsigned long p2, unsigned long m2) {
unsigned long mask;
mask= m1&m2;
- if ((p1 & mask) != (p2 & mask)) return;
+ return (p1 & mask) == (p2 & mask);
+}
+
+static void addrnet_mustdiffer(const char *w1, unsigned long p1, unsigned long m1,
+ const char *w2, unsigned long p2, unsigned long m2) {
+ if (!addrnet_overlap(p1,m1,p2,m2)) return;
badusage("%s %08lx/%08lx overlaps/clashes with %s %08lx/%08lx",
w1,p1,m1, w2,p2,m2);
}
sprintf(whatbuf,"%s length",what);
len= eat_number(argp,whatbuf, 0,32, endchars,endchar_r);
- mask= (~0UL << (32-len));
- if (prefix & ~mask) badusage("%s prefix %08lx not fully contained in mask %08lx\n",
+ mask= len ? (~0UL << (32-len)) : 0UL;
+ if (prefix & ~mask) badusage("%s prefix %08lx not fully contained in mask %08lx",
what,prefix,mask);
*prefix_r= prefix;
if (mask_r) *mask_r= mask;
unsigned long mprefix, unsigned long mmask) {
return !(~mask & mmask) && (prefix & mmask) == mprefix;
}
+
+/* Totally hideous algorithm for parsing the config file lines.
+ * For each config file line, we first see if its gid applies. If not
+ * we skip it. Otherwise, we do
+ * permit_begin
+ * which sets <foo>pming to 1
+ * for each range. <foo>pming may be 0 if we've determined that
+ * this line does not apply to <foo>.
+ * permit_range
+ * which calls permit_range_thing for each <foo>
+ * which checks to see if <foo> is inside the relevant
+ * range (for +) or overlaps it (for -) and updates
+ * <foo>allow and <foo>pming.
+ */
+
+static void permit_begin(void) {
+ int i;
+ localpming= peerpming= 1;
+ for (i=0; i<nexroutes; i++) exroutes[i].pming= 1;
+}
+
+static void permit_range_thing(unsigned long tprefix, unsigned long tmask,
+ const char *what, int *tallow, int *tpming,
+ unsigned long pprefix, unsigned long pmask,
+ int plus, int *any) {
+ if (plus) {
+ if (!addrnet_isin(tprefix,tmask, pprefix,pmask)) return;
+ if (*tpming) *tallow= 1;
+ } else {
+ if (!addrnet_overlap(tprefix,tmask, pprefix,pmask)) return;
+ *tpming= 0;
+ }
+ if (!proto) printf(" %c%s", plus?'+':'-', what);
+ *any= 1;
+}
-static void permit(unsigned long pprefix, unsigned long pmask) {
+static void permit_range(unsigned long prefix, unsigned long mask,
+ int plus, int localonly) {
int i, any;
+ char idbuf[40];
- assert(!(pprefix & ~pmask));
+ assert(!(prefix & ~mask));
+ any= 0;
- if (!proto) fputs("permits",stdout);
- if (addrnet_isin(localaddr,~0UL, pprefix,pmask)) {
- if (!proto) fputs(" local-addr",stdout);
- any= localallow= 1;
- }
- if (addrnet_isin(peeraddr,~0UL, pprefix,pmask)) {
- if (!proto) fputs(" peer-addr",stdout);
- any= peerallow= 1;
- }
- for (i=0; i<nexroutes; i++) {
- if (addrnet_isin(exroutes[i].prefix,exroutes[i].mask, pprefix,pmask)) {
- if (!proto) printf(" route#%d",i);
- any= exroutes[i].allow= 1;
+ permit_range_thing(localaddr,~0UL,"local", &localallow,&localpming,
+ prefix,mask, plus,&any);
+
+ if (!localonly) {
+ permit_range_thing(peeraddr,~0UL, "peer-addr", &peerallow,&peerpming,
+ prefix,mask, plus,&any);
+ for (i=0; i<nexroutes; i++) {
+ sprintf(idbuf,"route#%d",i);
+ permit_range_thing(exroutes[i].prefix,exroutes[i].mask, idbuf,
+ &exroutes[i].allow,&exroutes[i].pming,
+ prefix,mask, plus,&any);
}
}
- if (!proto) {
- if (!any) fputs(" nothing!",stderr);
- putchar('\n');
- }
+ if (!proto)
+ if (!any) fputs(" nothing",stdout);
}
static void pconfig(const char *configstr, int truncated);
static void pconfig(const char *configstr, int truncated) {
unsigned long fgid, tgid, pprefix, pmask;
- int plen;
+ int plen, localonly, plus, rangeix, delim;
char ptxt[ATXTLEN];
+ char whattxt[100];
const char *gidlist;
switch (configstr[0]) {
case '*':
- if (strcmp(configstr,"*")) badusage("`*' directive must be only thing on line");
- permit(0UL,0UL);
+ permit_begin();
+ permit_range(0UL,0UL,1,0);
return;
case '#':
badusage("unknown configuration directive");
fgid= eat_number(&configstr,"gid", 0,gidmaxval, ",",0);
- eat_prefixmask(&configstr,"permitted-prefix", ",",0, &pprefix,&pmask,&plen);
- if (!configstr && truncated) badusage("gid,prefix/len,... spec too long");
- if (!proto) printf(" %5lu,%s/%d: ", fgid, ip2txt(pprefix,ptxt), plen);
+ if (!proto) printf(" %5lu", fgid);
gidlist= getenv("USERV_GID");
if (!gidlist) fatal("USERV_GID not set");
for (;;) {
if (!gidlist) {
- if (!proto) printf("no matching gid\n");
+ if (!proto) printf(" no matching gid\n");
return;
}
tgid= eat_number(&gidlist,"userv-gid", 0,gidmaxval, " ",0);
if (tgid == fgid) break;
}
- permit(pprefix,pmask);
+
+ if (configstr[0] == '=') {
+ localonly= 1;
+ configstr++;
+ } else {
+ localonly= 0;
+ }
+
+ permit_begin();
+
+ rangeix= 0;
+ plus= 1;
+ switch (configstr[0]) {
+ case '-': plus= 0; /* fall through */
+ case '+': configstr++;
+ default:;
+ }
+
+ for (;;) {
+ sprintf(whattxt, "%s-prefix#%d",
+ plus ? "permitted" : "notpermitted",
+ rangeix);
+ eat_prefixmask(&configstr,whattxt, ",+-",&delim,
+ &pprefix,&pmask,&plen);
+ if (!configstr && truncated)
+ badusage("gid,prefix/len,... spec too long");
+
+ if (!proto)
+ printf(" %c%s/%d:", plus?'+':'-',ip2txt(pprefix,ptxt), plen);
+
+ permit_range(pprefix,pmask,plus,localonly);
+ if (delim==',') break;
+
+ plus= delim=='-' ? 0 : 1;
+ rangeix++;
+ }
+
+ putchar('\n');
return;
}
}
addrnet_mustdiffer("local-addr",localaddr,~0UL, "peer-addr",peeraddr,~0UL);
carg= *++argv;
- for (nexroutes=0;
- carg;
- nexroutes++) {
- if (nexroutes == MAXEXROUTES)
- fatal("too many extra routes (only %d allowed)",MAXEXROUTES);
- sprintf(erwhatbuf,"route#%d",nexroutes);
+ if (strcmp(carg,"-")) {
+ for (nexroutes=0;
+ carg && *carg;
+ nexroutes++) {
+ if (nexroutes == MAXEXROUTES)
+ fatal("too many extra routes (only %d allowed)",MAXEXROUTES);
+ sprintf(erwhatbuf,"route#%d",nexroutes);
- eat_prefixmask(&carg,erwhatbuf, ",",0, &routeaddr,&routemask,0);
- if (routemask == ~0UL) {
- addrnet_mustdiffer(erwhatbuf,routeaddr,routemask, "local-addr",localaddr,~0UL);
- addrnet_mustdiffer(erwhatbuf,routeaddr,routemask, "peer-addr",peeraddr,~0UL);
- }
- for (i=0; i<nexroutes; i++) {
- sprintf(erwhatbuf2,"route#%d",i);
- addrnet_mustdiffer(erwhatbuf,routeaddr,routemask,
- erwhatbuf2,exroutes[i].prefix,exroutes[i].mask);
+ eat_prefixmask(&carg,erwhatbuf, ",",0, &routeaddr,&routemask,0);
+ if (routemask == ~0UL) {
+ addrnet_mustdiffer(erwhatbuf,routeaddr,routemask, "local-addr",localaddr,~0UL);
+ addrnet_mustdiffer(erwhatbuf,routeaddr,routemask, "peer-addr",peeraddr,~0UL);
+ }
+ for (i=0; i<nexroutes; i++) {
+ sprintf(erwhatbuf2,"route#%d",i);
+ addrnet_mustdiffer(erwhatbuf,routeaddr,routemask,
+ erwhatbuf2,exroutes[i].prefix,exroutes[i].mask);
+ }
+ exroutes[nexroutes].prefix= routeaddr;
+ exroutes[nexroutes].mask= routemask;
+ exroutes[nexroutes].allow= 0;
+ ip2txt(routeaddr,exroutes[nexroutes].prefixtxt);
+ ip2txt(routemask,exroutes[nexroutes].masktxt);
}
- exroutes[nexroutes].prefix= routeaddr;
- exroutes[nexroutes].mask= routemask;
- exroutes[nexroutes].allow= 0;
- ip2txt(routeaddr,exroutes[nexroutes].prefixtxt);
- ip2txt(routemask,exroutes[nexroutes].masktxt);
}
+
ip2txt(localaddr,localtxt);
ip2txt(peeraddr,peertxt);
}
}
setsigmask(&fullset);
l= strlen(ifnbuf);
- if (l<0 || ifnbuf[l-1] != '\n') fatal("slattach gave strange output `%s'",ifnbuf);
+ if (l<=0 || ifnbuf[l-1] != '\n') fatal("slattach gave strange output `%s'",ifnbuf);
ifnbuf[l-1]= 0;
for (k=l; k>0 && ifnbuf[k-1]!=' '; k--);
ifname= ifnbuf+k;
sysfatal("cannot exec ifconfig");
}
- if (task()) {
- execlp("route","route", "add", "-host",localtxt,
- "dev",ifname, (char*)0);
- sysfatal("cannot exec route (for local)");
- }
-
- if (task()) {
- execlp("route","route", "add", "-host",peertxt,
- "dev",ifname, (char*)0);
- sysfatal("cannot exec route (for peer)");
- }
-
for (i=0; i<nexroutes; i++) {
if (task()) {
execlp("route","route", "add", "-net",exroutes[i].prefixtxt,
}
static void copydata(void) __attribute__((noreturn));
-static void copydata(void) {
+static void copydata(void) {
+ int r;
+
pids.byname.cin= makesubproc(cin_entry);
+ for (;;) {
+ r= write(1, "\300", 1); if (r==1) break;
+ assert(r==-1); if (errno != EINTR) sysfatal("send initial delim to confirm");
+ }
pids.byname.cout= makesubproc(cout_entry);
for (;;) sigsuspend(&emptyset);
~ian / userv-utils.git / blobdiff