/*
- * userv service (or standalone program)
- * for per-user IP subranges.
+ * userv service (or standalone program) for per-user IP subranges.
+ *
+ * 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':
+ *
+ * <config>
+ *
+ * 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>][,[<ifnamepat>]]]
+ *
+ * As for slattach. The only supported protocol is slip.
+ * 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).
*
- * This is invoked as root, directly from userv.
- * Its arguments are supposed to be, in order:
- * <base-prefix>/<base-prefix-len>
- * Specifies the base address and prefix to restrict the
- * addresses used to.
- * <gid-min>-<gid-max>:<gid-add>/<gid-mask>[,...]
- * The ranges specified by <gid-min> are checked <gid-max> until
- * one is found which matches at least one gid in USERV_GID.
- * Then the gid will have <gid-add> added to it and will then be
- * masked so that it is <gid-mask> long (higher set bits are
- * discarded). The result is added to the base prefix. It is an
- * error for no gid to match. Alternatively, if this argument
- * is `*' then USERV_GID is not checked.
- * -- Indicates that the remaining arguments are user-supplied
- * and therefore untrusted.
- * <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.
* <prefix>/<mask>,<prefix>/<mask>,...
- * List of additional routes to add for this interface.
- * May be the empty argument.
*
- * 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 in a file such as
+ * /etc/userv/ipif-networks, or the single trusted argument 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.
+ *
+ * Only `*' permits interface name patterns other than the default
+ * value of `userv%d'.
+ *
+ * #...
+ *
+ * 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.
+ */
+/*
+ * This file is part of ipif, part of userv-utils
+ *
+ * Copyright 1996-2013 Ian Jackson <ijackson@chiark.greenend.org.uk>
+ * Copyright 1998 David Damerell <damerell@chiark.greenend.org.uk>
+ * Copyright 1999,2003
+ * Chancellor Masters and Scholars of the University of Cambridge
+ * Copyright 2010 Tony Finch <fanf@dotat.at>
+ *
+ * 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 3 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, see http://www.gnu.org/licenses/.
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
+#include <stdarg.h>
+#include <ctype.h>
+#include <limits.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <poll.h>
+#include <stddef.h>
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
-#define NARGS 5
-#define MAXEXROUTES 5
-#define ATXTLEN 12
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
-static const char *proto;
-static unsigned long baseprefix, basemask;
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include <linux/if.h>
+#include <linux/if_tun.h>
+
+#define NARGS 4
+#define MAXEXROUTES 50
+#define ATXTLEN 16
+
+static const unsigned long gidmaxval= (unsigned long)((gid_t)-2);
+static const char *const protos_ok[]= { "slip", 0 };
+static const int signals[]= { SIGHUP, SIGINT, SIGTERM, 0 };
+static const char default_ifnamepat[]= "userv%d";
+
+static const char *configstr, *proto;
static unsigned long localaddr, peeraddr, mtu;
+static int localpming, peerpming;
+static int localallow, peerallow, ifnameallow, allallow;
+static char *ifnamepat;
static int nexroutes;
static struct exroute {
unsigned long prefix, mask;
+ int allow, pming;
char prefixtxt[ATXTLEN], masktxt[ATXTLEN];
} exroutes[MAXEXROUTES];
-char localtxt[ATXTLEN];
-char peertxt[ATXTLEN];
+static char localtxt[ATXTLEN];
+static char peertxt[ATXTLEN];
+
+static struct pplace {
+ struct pplace *parent;
+ const char *filename;
+ int lineno;
+} *cpplace;
+
+
+static int tunfd;
+static char *ifname;
-static void fatal(const char *msg) {
- fprintf(stderr,"userv-ipif: service: fatal error: %s\n",msg);
- exit(8);
+
+static void terminate(int estatus) {
+ exit(estatus);
+}
+
+
+static void fatal(const char *fmt, ...)
+ __attribute__((format(printf,1,2)));
+static void fatal(const char *fmt, ...) {
+ va_list al;
+ va_start(al,fmt);
+
+ fputs("userv-ipif service: fatal error: ",stderr);
+ vfprintf(stderr, fmt, al);
+ putc('\n',stderr);
+ terminate(8);
}
-static void sysfatal(const char *msg) {
- fprintf(stderr,"userv-ipif: service: fatal system error: %s: %s\n",
- msg, strerror(errno));
- exit(12);
+static void sysfatal(const char *fmt, ...)
+ __attribute__((format(printf,1,2)));
+static void sysfatal(const char *fmt, ...) {
+ va_list al;
+ int e;
+
+ e= errno;
+ va_start(al,fmt);
+
+ fputs("userv-ipif service: fatal system error: ",stderr);
+ vfprintf(stderr, fmt, al);
+ fprintf(stderr,": %s\n", strerror(e));
+ terminate(12);
}
+
+
+static void badusage(const char *fmt, ...)
+ __attribute__((format(printf,1,2)));
+static void badusage(const char *fmt, ...) {
+ va_list al;
+ struct pplace *cpp;
-static void badusage(void) {
- fputs("userv-ipif: service: bad usage or permission denied\n",stderr);
- exit(16);
+ if (cpplace) {
+ fprintf(stderr,
+ "userv-ipif service: %s:%d: ",
+ cpplace->filename, cpplace->lineno);
+ } else {
+ fputs("userv-ipif service: invalid usage: ",stderr);
+ }
+ va_start(al,fmt);
+ vfprintf(stderr, fmt, al);
+ putc('\n',stderr);
+
+ if (cpplace) {
+ for (cpp=cpplace->parent; cpp; cpp=cpp->parent) {
+ fprintf(stderr,
+ "userv-ipif service: %s:%d: ... in file included from here\n",
+ cpp->filename, cpp->lineno);
+ }
+ }
+ terminate(16);
}
static char *ip2txt(unsigned long addr, char *buf) {
char *ep;
int endchar;
- if (!*argp) { fprintf(stderr,"missing number %s\n",what); badusage(); }
+ if (!*argp) { badusage("missing number %s",what); }
rv= strtoul(*argp,&ep,0);
if ((endchar= *ep)) {
- if (!endchars) { fprintf(stderr,"junk after number %s\n",what); badusage(); }
- if (!strchr(endchars,endchar)) {
- fprintf(stderr,"invalid delimiter %c after number %s: expected %s (or none?)\n",
- endchar,what,endchars);
- badusage();
- }
+ 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?)", endchar,what,endchars);
*argp= ep+1;
} else {
*argp= 0;
}
if (endchar_r) *endchar_r= endchar;
- if (rv < min || rv > max) {
- fprintf(stderr,"number %s value %lu out of range %lu..%lu",
- what, rv, min, max);
- badusage();
- }
+ if (rv < min || rv > max) badusage("number %s value %lu out of range %lu..%lu",
+ what, rv, min, max);
return rv;
}
-static void addrnet_mustbein(const char *what,
- unsigned long prefix, unsigned long mask,
- unsigned long mprefix, unsigned long mmask) {
- if (!(~mask & mmask) && (prefix & mmask) == mprefix) return;
- fprintf(stderr, "%s %08lx/%08lx not in required subspace %08lx/%08lx\n",
- what, prefix, mask, mprefix, mmask);
- badusage();
+static int addrnet_overlap(unsigned long p1, unsigned long m1,
+ unsigned long p2, unsigned long m2) {
+ unsigned long mask;
+
+ mask= m1&m2;
+ 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) {
- unsigned long mask;
-
- mask= m1&m2;
- if ((p1 & mask) != (p2 & mask)) return;
- fprintf(stderr, "%s %08lx/%08lx overlaps/clashes with %s %08lx/%08lx",
- w1,p1,m1, w2,p2,m2);
- badusage();
+ if (!addrnet_overlap(p1,m1,p2,m2)) return;
+ badusage("%s %08lx/%08lx overlaps/clashes with %s %08lx/%08lx",
+ w1,p1,m1, w2,p2,m2);
}
static unsigned long eat_addr(const char **argp, const char *what,
- unsigned long mprefix, unsigned long mmask,
const char *endchars, int *endchar_r) {
char whatbuf[100];
unsigned long rv;
int i;
- assert(!(~mmask & mprefix));
-
for (rv=0, i=0;
i<4;
i++) {
rv |= eat_number(argp,whatbuf, 0,255, i<3 ? "." : endchars, endchar_r);
}
- addrnet_mustbein(what,rv,~0UL, mprefix,mmask);
return rv;
}
static void eat_prefixmask(const char **argp, const char *what,
- unsigned long mprefix, unsigned long mmask,
const char *endchars, int *endchar_r,
unsigned long *prefix_r, unsigned long *mask_r, int *len_r) {
/* mask_r and len_r may be 0 */
int len;
unsigned long prefix, mask;
- prefix= eat_addr(argp,what, 0,0, "/",0);
+ prefix= eat_addr(argp,what, "/",0);
sprintf(whatbuf,"%s length",what);
len= eat_number(argp,whatbuf, 0,32, endchars,endchar_r);
- mask= (~0UL << (32-len));
- if (prefix & ~mask) {
- fprintf(stderr,"%s prefix %08lx not fully contained in mask %08lx\n",
- what,prefix,mask);
- badusage();
- }
- addrnet_mustbein(what,prefix,mask, mprefix,mmask);
+ 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;
if (len_r) *len_r= len;
}
+
+static char *eat_optionalstr(const char **argp,
+ const char *what,
+ const char *def) {
+ ptrdiff_t len;
+ const char *start= *argp;
+ if (!start) {
+ len = 0;
+ } else {
+ const char *comma= strchr(start, ',');
+ if (comma) {
+ len= comma - start;
+ *argp= comma + 1;
+ } else {
+ len= strlen(start);
+ *argp= 0;
+ }
+ }
+ if (!len) {
+ start= def;
+ len= strlen(def);
+ }
+ char *r = malloc(len+1);
+ if (!r) sysfatal("malloc for command line string");
+ memcpy(r,start,len);
+ r[len]= 0;
+ return r;
+}
+
+static int addrnet_isin(unsigned long prefix, unsigned long 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;
-int main(int argc, const char *const *argv) {
- static unsigned long gidmaxval= (unsigned long)((gid_t)-2);
- static const char *const protos_ok[]= { "slip", "cslip", "adaptive", 0 };
+ localpming= peerpming= 1;
+ for (i=0; i<nexroutes; i++) exroutes[i].pming= 1;
+}
- unsigned long gidmin, gidmax, gidadd;
- int baselen;
- unsigned long routeaddr, routemask, tgid;
- const char *carg, *gidlist;
- const char *const *cprotop;
- int gidlen, i;
- char erwhatbuf[100], erwhatbuf2[100];
+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_range(unsigned long prefix, unsigned long mask,
+ int plus, int localonly) {
+ int i, any;
+ char idbuf[40];
- if (argc < NARGS+1) { fputs("too few arguments\n",stderr); badusage(); }
- if (argc > NARGS+1) { fputs("too many arguments\n",stderr); badusage(); }
+ assert(!(prefix & ~mask));
+ any= 0;
- carg= *++argv;
- eat_prefixmask(&carg,"base", 0UL,0UL, 0,0, &baseprefix, &basemask, &baselen);
+ permit_range_thing(localaddr,~0UL,"local", &localallow,&localpming,
+ prefix,mask, plus,&any);
- carg= *++argv;
- if (!strcmp(carg,"*")) {
+ 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",stdout);
+}
+
+static void pconfig(const char *configstr, int truncated);
+
+static void pfile(const char *filename) {
+ FILE *file;
+ char buf[PATH_MAX];
+ int l, truncated, c;
+ struct pplace npp, *cpp;
+
+ for (cpp=cpplace; cpp; cpp=cpp->parent) {
+ if (!strcmp(cpp->filename,filename))
+ badusage("recursive configuration file `%s'",filename);
+ }
+
+ file= fopen(filename,"r");
+ if (!file)
+ badusage("cannot open configuration file `%s': %s", filename, strerror(errno));
+
+ if (!proto) printf("config file `%s':\n",filename);
+
+ npp.parent= cpplace;
+ npp.filename= filename;
+ npp.lineno= 0;
+ cpplace= &npp;
+
+ while (fgets(buf, sizeof(buf), file)) {
+ npp.lineno++;
+ l= strlen(buf);
+ if (!l) continue;
+
+ truncated= (buf[l-1] != '\n');
+ while (l>0 && isspace((unsigned char) buf[l-1])) l--;
+ if (!l) continue;
+ buf[l]= 0;
+
+ if (truncated) {
+ while ((c= getc(file)) != EOF && c != '\n');
+ if (c == EOF) break;
+ }
+
+ pconfig(buf,truncated);
+ }
+ if (ferror(file))
+ badusage("failed while reading configuration file: %s", strerror(errno));
+
+ cpplace= npp.parent;
+ fclose(file);
+}
+
+static void pconfig(const char *configstr, int truncated) {
+ unsigned long fgid, tgid, pprefix, pmask;
+ int plen, localonly, plus, rangeix, delim;
+ char ptxt[ATXTLEN];
+ char whattxt[100];
+ const char *gidlist;
+
+ switch (configstr[0]) {
+ case '*':
+ permit_begin();
+ permit_range(0UL,0UL,1,0);
+ ifnameallow= 1;
+ return;
+
+ case '#':
+ return;
+
+ case '/': case '.':
+ if (truncated) badusage("filename too long (`%.100s...')",configstr);
+ pfile(configstr);
+ return;
+
+ default:
+ if (!isdigit((unsigned char)configstr[0]))
+ badusage("unknown configuration directive");
+
+ fgid= eat_number(&configstr,"gid", 0,gidmaxval, ",",0);
+
+ if (!proto) printf(" %5lu", fgid);
+
+ gidlist= getenv("USERV_GID");
+ if (!gidlist) fatal("USERV_GID not set");
for (;;) {
- if (!*carg) fatal("no gid authorised");
- gidmin= eat_number(&carg,"gid-min", 0,gidmaxval, "-",0);
- gidmax= eat_number(&carg,"gid-max", gidmin,gidmaxval, ":",0);
- gidadd= eat_number(&carg,"gid-add", 0,gidmaxval, "/",0);
- gidlen= eat_number(&carg,"gid-len", 0,32-baselen, 0,0);
-
- gidlist= getenv("USERV_GID");
- if (!gidlist) fatal("USERV_GID not set");
- while (gidlist) {
- tgid= eat_number(&gidlist,"userv_gid", 0,gidmaxval, " ",0);
- if (tgid >= gidmin && tgid <= gidmax) goto gid_found;
+ if (!gidlist) {
+ if (!proto) printf(" no matching gid\n");
+ return;
}
+ tgid= eat_number(&gidlist,"userv-gid", 0,gidmaxval, " ",0);
+ if (tgid == fgid) break;
}
- gid_found:
- tgid += gidadd;
- tgid &= ((1UL << gidlen) - 1);
- baselen += gidlen;
- baseprefix |= (tgid << (32-baselen));
- basemask = (~0UL << (32-baselen));
- } else {
- tgid= 0;
+
+ 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;
}
+}
+
+static void checkallow(int allow, const char *what,
+ const char *prefixtxt, const char *masktxt) {
+ if (allow) return;
+ fprintf(stderr,"userv-ipif service: access denied for %s, %s/%s\n",
+ what, prefixtxt, masktxt);
+ allallow= 0;
+}
+
+static void parseargs(int argc, const char *const *argv) {
+ unsigned long routeaddr, routemask;
+ const char *carg;
+ const char *const *cprotop;
+ int i;
+ char erwhatbuf[100], erwhatbuf2[100];
+
+ if (argc < NARGS+1) { badusage("too few arguments"); }
+ if (argc > NARGS+1) { badusage("too many arguments"); }
+
+ configstr= *++argv;
carg= *++argv;
+ if (strcmp(carg,"--")) badusage("separator argument `--' not found, got `%s'",carg);
- localaddr= eat_addr(&carg,"local-addr", baseprefix,basemask, ",",0);
- peeraddr= eat_addr(&carg,"peer-addr", baseprefix,basemask, ",",0);
+ carg= *++argv;
+ localaddr= eat_addr(&carg,"local-addr", ",",0);
+ peeraddr= eat_addr(&carg,"peer-addr", ",",0);
mtu= eat_number(&carg,"mtu", 576,65536, ",",0);
-
- if (!strcmp(carg,"debug")) {
+ localallow= peerallow= 0;
+
+ char *protostr= eat_optionalstr(&carg,"protocol","slip");
+ if (!strcmp(protostr,"debug")) {
proto= 0;
} else {
for (cprotop= protos_ok;
- (proto= *cprotop) && strcmp(proto,carg);
+ (proto= *cprotop) && strcmp(proto,protostr);
cprotop++);
if (!proto) fatal("invalid protocol");
}
+
+ ifnamepat= eat_optionalstr(&carg,"ifname pattern",default_ifnamepat);
addrnet_mustdiffer("local-addr",localaddr,~0UL, "peer-addr",peeraddr,~0UL);
carg= *++argv;
- for (nexroutes=0;
- *carg;
- carg++, nexroutes++) {
- if (nexroutes == MAXEXROUTES) {
- fprintf(stderr,"only %d extra routes allowed\n",MAXEXROUTES);
- fatal("too many extra routes");
- }
- sprintf(erwhatbuf,"route %d",nexroutes+1);
+ 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, baseprefix,basemask, ",",0, &routeaddr,&routemask,0);
- 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+1);
- 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;
- ip2txt(routeaddr,exroutes[nexroutes].prefixtxt);
- ip2txt(routemask,exroutes[nexroutes].masktxt);
}
+
ip2txt(localaddr,localtxt);
ip2txt(peeraddr,peertxt);
+}
+
+static void checkpermit(void) {
+ int i;
+ char erwhatbuf[100];
- if (!proto) {
- char basetxt[ATXTLEN];
-
- printf("protocol: debug\n"
- "base: %08lx/%-2ld == %s/%ld\n"
- "auth gid: %ld"
- "local: %08lx == %s\n"
- "peer: %08lx == %s\n"
- "mtu: %ld"
- "routes: %d",
- baseprefix, basemask, ip2txt(baseprefix,basetxt), basemask,
- tgid,
- localaddr, localtxt,
- peeraddr, peertxt,
- mtu,
- nexroutes);
- for (i=0; i<nexroutes; i++) {
- sprintf(erwhatbuf2, "route %d:", i+1);
- printf("%-9s %08lx/%-2ld == %s/%s\n",
- erwhatbuf,
- exroutes[i].prefix, exroutes[i].mask,
- exroutes[i].prefixtxt, exroutes[i].masktxt);
+ allallow= 1;
+ checkallow(localallow,"local-addr", localtxt,"32");
+ checkallow(peerallow,"peer-addr", peertxt,"32");
+ for (i=0; i<nexroutes; i++) {
+ sprintf(erwhatbuf, "route#%d", i);
+ checkallow(exroutes[i].allow, erwhatbuf, exroutes[i].prefixtxt, exroutes[i].masktxt);
+ }
+ if (!strcmp(ifnamepat,default_ifnamepat))
+ ifnameallow= 1;
+ if (!ifnameallow) {
+ fprintf(stderr,
+ "userv-ipif service: access denied for interface name %s\n",
+ ifnamepat);
+ allallow= 0;
+ }
+ if (!allallow) fatal("access denied");
+}
+
+static void dumpdebug(void) __attribute__((noreturn));
+static void dumpdebug(void) {
+ int i;
+ char erwhatbuf[100];
+
+ printf("protocol: debug\n"
+ "local: %08lx == %s\n"
+ "peer: %08lx == %s\n"
+ "mtu: %ld\n"
+ "routes: %d\n",
+ localaddr, localtxt,
+ peeraddr, peertxt,
+ mtu,
+ nexroutes);
+ for (i=0; i<nexroutes; i++) {
+ sprintf(erwhatbuf, "route#%d:", i);
+ printf("%-9s %08lx/%08lx == %s/%s\n",
+ erwhatbuf,
+ exroutes[i].prefix, exroutes[i].mask,
+ exroutes[i].prefixtxt, exroutes[i].masktxt);
+ }
+ if (ferror(stdout) || fclose(stdout)) sysfatal("flush stdout");
+ exit(0);
+}
+
+
+static int task(const char *desc) {
+ pid_t pid, pidr;
+ int status;
+
+ pid= fork();
+ if (pid == (pid_t)-1) sysfatal("fork for task");
+ if (!pid) return 1;
+
+ for (;;) {
+ pidr= waitpid(pid,&status,0);
+ if (pidr!=(pid_t)-1) break;
+ if (errno==EINTR) continue;
+ sysfatal("waitpid for task");
+ }
+ assert(pidr==pid);
+
+ if (WIFEXITED(status)) {
+ if (WEXITSTATUS(status))
+ fatal("userv-ipif service: %s exited with error exit status %d\n",
+ desc, WEXITSTATUS(status));
+ } else if (WIFSIGNALED(status)) {
+ fatal("userv-ipif service: %s died due to signal %s%s\n",
+ desc, strsignal(WTERMSIG(status)),
+ WCOREDUMP(status) ? " (core dumped)" : "");
+ } else {
+ fatal("userv-ipif service: %s unexpectedly terminated"
+ " with unknown status code %d\n", desc, status);
+ }
+
+ return 0;
+}
+
+static void createif(void) {
+ struct ifreq ifr;
+ int r;
+
+ memset(&ifr,0,sizeof(ifr));
+ ifr.ifr_flags= IFF_TUN | IFF_NO_PI;
+
+ assert(sizeof(ifr.ifr_name) >= strlen(ifnamepat)+1);
+ strcpy(ifr.ifr_name, ifnamepat);
+
+ tunfd= open("/dev/net/tun", O_RDWR);
+ if (!tunfd) sysfatal("open /dev/net/tun");
+
+ r= fcntl(tunfd, F_GETFD);
+ if (r==-1) sysfatal("fcntl(tunfd,F_GETFD)");
+ r= fcntl(tunfd, F_SETFD, r|FD_CLOEXEC);
+ if (r==-1) sysfatal("fcntl(tunfd,F_SETFD,|FD_CLOEXEC)");
+
+ r= ioctl(tunfd, TUNSETIFF, (void*)&ifr);
+ if (r) sysfatal("ioctl TUNSETIFF");
+
+ /* ifr.ifr_name might not be null-terminated. crazy abi. */
+ ifname= malloc(sizeof(ifr.ifr_name)+1);
+ if (!ifname) sysfatal("malloc for interface name");
+ memcpy(ifname, ifr.ifr_name, sizeof(ifr.ifr_name));
+ ifname[sizeof(ifr.ifr_name)]= 0;
+}
+
+static void netconfigure(void) {
+ char mtutxt[100];
+ int i;
+
+ if (task("ifconfig")) {
+ sprintf(mtutxt,"%lu",mtu);
+
+ execlp("ifconfig", "ifconfig", ifname, localtxt,
+ "netmask","255.255.255.255", "pointopoint",peertxt, "-broadcast",
+ "mtu",mtutxt, "up", (char*)0);
+ sysfatal("cannot exec ifconfig");
+ }
+
+ for (i=0; i<nexroutes; i++) {
+ if (task("route")) {
+ execlp("route","route", "add", "-net",exroutes[i].prefixtxt,
+ "netmask",exroutes[i].masktxt,
+ "gw",peertxt, "dev",ifname, (char*)0);
+ sysfatal("cannot exec route (for route)");
+ }
+ }
+}
+
+static void setnonblock(int fd) {
+ int r;
+ r= fcntl(fd,F_GETFL);
+ if (r==-1) sysfatal("fcntl F_GETFL");
+ r= fcntl(fd,F_SETFL, r|O_NONBLOCK);
+ if (r==-1) sysfatal("fcntl F_SETFL O_NONBLOCK");
+}
+
+static void rx_packet(const uint8_t *packet, int len) {
+ if (!len)
+ return;
+ for (;;) {
+ int r= write(tunfd, packet, len);
+ if (r<0) {
+ if (errno==EINTR) continue;
+ if (errno==EAGAIN || errno==ENOMEM) return; /* oh well */
+ sysfatal("error writing packet to tun (transmitting)");
}
- if (ferror(stdout) || fclose(stdout)) sysfatal("flush stdout");
- exit(0);
+ assert(r==len);
+ return;
}
- abort();
+}
+
+static int output_waiting, input_waiting;
+
+#define SLIP_END 0300
+#define SLIP_ESC 0333
+#define SLIP_ESC_END 0334
+#define SLIP_ESC_ESC 0335
+
+static void more_rx_data(uint8_t *input_buf, uint8_t *output_buf) {
+ /* we make slip_data never contain continuation of a packet */
+ /* input_buf is passed as a parameter since it's in copydata's stack frame */
+ static int scanned;
+ static int output_len;
+
+ uint8_t *op= output_buf + output_len;
+ const uint8_t *ip= input_buf + scanned;
+ const uint8_t *ip_end= input_buf + input_waiting;
+ int eaten= 0;
+
+ for (;;) {
+ if (ip>=ip_end) break;
+ uint8_t c= *ip++;
+ if (c==SLIP_END) {
+ rx_packet(output_buf, op-output_buf);
+ op= output_buf;
+ eaten= ip - input_buf;
+ continue;
+ }
+ if (c==SLIP_ESC) {
+ if (ip>=ip_end) { /* rescan this when there's more */ ip--; break; }
+ c= *ip++;
+ if (c==SLIP_ESC_END) c=SLIP_END;
+ else if (c==SLIP_ESC_ESC) c=SLIP_ESC;
+ else fatal("unexpected byte 0%o after SLIP_ESC",c);
+ }
+ if (op == output_buf+mtu)
+ fatal("SLIP packet exceeds mtu");
+ *op++= c;
+ }
+
+ output_len= op - output_buf;
+ scanned= ip - input_buf;
+
+ input_waiting -= eaten;
+ memmove(input_buf, input_buf+eaten, input_waiting);
+ scanned -= eaten;
+}
+
+static void tx_packet(uint8_t *output_buf, const uint8_t *ip, int inlen) {
+ /* output_buf is passed as a parameter since it's in copydata's stack frame */
+ assert(!output_waiting);
+ uint8_t *op= output_buf;
+
+ *op++= SLIP_END;
+ while (inlen-- >0) {
+ uint8_t c= *ip++;
+ if (c==SLIP_END) { *op++= SLIP_ESC; *op++= SLIP_ESC_END; }
+ else if (c==SLIP_ESC) { *op++= SLIP_ESC; *op++= SLIP_ESC_ESC; }
+ else *op++= c;
+ }
+ *op++= SLIP_END;
+ assert(op <= output_buf + mtu*2+2);
+
+ output_waiting= op - output_buf;
+}
+
+static void copydata(void) __attribute__((noreturn));
+static void copydata(void) {
+ uint8_t output_buf[mtu*2+2];
+ uint8_t input_buf[mtu*2+2];
+ uint8_t rx_packet_buf[mtu];
+
+ int r, i;
+
+ struct pollfd polls[3];
+ memset(polls, 0, sizeof(polls));
+
+ polls[0].fd= 0; polls[0].events= POLLIN;
+ polls[1].fd= 1;
+ polls[2].fd= tunfd;
+
+ /* We don't do flow control on input packets; instead, we just throw
+ * away ones which the kernel doesn't accept. So we always poll for
+ * those.
+ *
+ * Output packets we buffer, so we poll only as appropriate for those.
+ */
+
+ /* Start by transmitting one END byte to say we're ready. */
+ output_buf[0]= SLIP_END;
+ output_waiting= 1;
+
+ for (;;) {
+ if (output_waiting) {
+ r= write(1, output_buf, output_waiting);
+ if (r<0) {
+ if (errno==EINTR) continue;
+ if (errno!=EAGAIN)
+ sysfatal("error writing SLIP output (packets being received)");
+ } else {
+ assert(r>0);
+ output_waiting -= r;
+ memmove(output_buf, output_buf+r, output_waiting);
+ }
+ }
+ if (output_waiting) {
+ polls[1].events |= POLLOUT;
+ polls[2].events &= ~POLLIN;
+ } else {
+ polls[1].events &= ~POLLOUT;
+ polls[2].events |= POLLIN;
+ }
+ r= poll(polls,3,-1);
+
+ if (r<0) {
+ if (errno==EINTR) continue;
+ sysfatal("poll() failed");
+ }
+ assert(r>0); /* we used an infinite timeout */
+
+ for (i=0; i<sizeof(polls)/sizeof(polls[0]); i++)
+ if (polls[i].revents & ~polls[i].events)
+ fatal("unexpected revents 0x%x for fd=%d",
+ polls[i].revents, polls[i].fd);
+
+ if (polls[0].events & POLLIN) {
+ int want= sizeof(input_buf) - input_waiting;
+ if (want<0) fatal("incoming packet necessarily exceeds MTU");
+ r= read(0, input_buf + input_waiting, want);
+ if (r>0) {
+ input_waiting += r;
+ assert(input_waiting <= sizeof(input_buf));
+ more_rx_data(input_buf, rx_packet_buf);
+ } else if (r==0) {
+ terminate(0);
+ } else {
+ if (!(errno==EINTR || errno==EAGAIN))
+ sysfatal("error reading input SLIP data (packets to transmit)");
+ }
+ }
+
+ /* We handle what would be (polls[1].events & POLLOUT) above,
+ * unconditionally. That eliminates the need to poll in the usual case */
+
+ if (polls[2].events & POLLIN) {
+ uint8_t packet_buf[mtu];
+ r= read(tunfd, packet_buf, mtu);
+ if (r>0) {
+ tx_packet(output_buf, packet_buf, r);
+ } else {
+ assert(r<0);
+ if (!(errno==EAGAIN || errno==EWOULDBLOCK))
+ sysfatal("error reading packet (being transmitted) from tun");
+ }
+ }
+ }
+}
+
+int main(int argc, const char *const *argv) {
+ parseargs(argc,argv);
+ pconfig(configstr,0);
+ checkpermit();
+ if (!proto) dumpdebug();
+
+ createif();
+ netconfigure();
+ setnonblock(tunfd);
+ setnonblock(0);
+ setnonblock(1);
+ copydata();
}
~ian / userv-utils.git / blobdiff