/*
- * 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.
+ *
+ * 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).
+ *
* <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 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.
+ *
+ * #...
+ *
+ * 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 <stdarg.h>
#include <ctype.h>
#include <limits.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <poll.h>
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include <linux/if.h>
+#include <linux/if_tun.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 *const protos_ok[]= { "slip", 0 };
+static const int signals[]= { SIGHUP, SIGINT, SIGTERM, 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];
int lineno;
} *cpplace;
+
+static int tunfd;
+static char *ifname;
+
+
+static void terminate(int estatus) {
+ exit(estatus);
+}
+
+
static void fatal(const char *fmt, ...)
__attribute__((format(printf,1,2)));
static void fatal(const char *fmt, ...) {
fputs("userv-ipif service: fatal error: ",stderr);
vfprintf(stderr, fmt, al);
putc('\n',stderr);
- exit(8);
+ terminate(8);
}
static void sysfatal(const char *fmt, ...)
e= errno;
va_start(al,fmt);
- fputs("userv-ipif service: fatal system error",stderr);
+ fputs("userv-ipif service: fatal system error: ",stderr);
vfprintf(stderr, fmt, al);
- fprintf(stderr,"%s\n", strerror(e));
- exit(12);
+ fprintf(stderr,": %s\n", strerror(e));
+ terminate(12);
}
cpp->filename, cpp->lineno);
}
}
- exit(16);
+ terminate(16);
}
static char *ip2txt(unsigned long addr, char *buf) {
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(unsigned long pprefix, unsigned long pmask) {
+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];
- 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);
}
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) {
+ static const char ifnamepat[]= "userv%d";
+ struct ifreq ifr;
+ int r;
+
+ memset(&ifr,0,sizeof(ifr));
+ ifr.ifr_flags= IFF_TUN | IFF_NO_PI;
+
+ assert(sizeof(ifr.ifr_name) >= sizeof(ifnamepat));
+ 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)");
+ }
+ assert(r==len);
+ return;
+ }
+}
+
+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();
- abort();
+ createif();
+ netconfigure();
+ setnonblock(tunfd);
+ setnonblock(0);
+ setnonblock(1);
+ copydata();
}
~ian / userv-utils.git / blobdiff