X-Git-Url: https://git.distorted.org.uk/~mdw/userv-utils/blobdiff_plain/1fb3cba0b41ae774f83c11d2a9c23b12b2c87d1a..0f91e8747cef1e27788ddce4b32563e0c105dbb3:/ipif/forwarder.c?ds=sidebyside

diff --git a/ipif/forwarder.c b/ipif/forwarder.c
index ae32786..793ad24 100644
--- a/ipif/forwarder.c
+++ b/ipif/forwarder.c
@@ -1,20 +1,28 @@
 /*
  * Encrypting tunnel for userv-ipif tunnels, actual implementation
- *
+ */
+/*
  * usage:
- *  udptunnel-forwarder <public-local-fd> <private-in-fd> <private-out-fd>
- *                      <mtu> <keepalive> <timeout>
+ *  udptunnel-forwarder <optchars>
+ *                      <public-local-fd> <private-in-fd> <private-out-fd>
+ *                      <encdec-keys-fd>
+ *                      <mtu> <keepalive> <timeout> <reannounce>
  *                      <public-remote-addr> [<public-remote-port>]
- *                      <encdec-keys-fd> <encdec-keys-write>
- *                      <mech1> [<mech1-params> ...]
- *                      <mech2> [<mech2-params> ...]
+ *                      |<mech1> [<mech1-params> ...]
+ *                      |<mech2> [<mech2-params> ...]
  *                      ''
  *
  * Remote addr may '' to mean wait to receive a packet and reply to
  * whereever we get a good packet from first, in which case port
  * should not be specified.
  *
- * <enc-keys-write> is '' to mean read, anything else to mean write.
+ * <optchars> is zero or more of
+ *    w   means generate and write encdec keys, rather than reading them
+ *    K   means do crypto debug (use with care!)
+ *
+ * encdec keys datastream has keys for packets from key datastream
+ * writer to reader first, then keys for packets from reader to
+ * writer.
  *
  * Every must be numeric.  There is very little argument checking.
  *
@@ -26,6 +34,23 @@
  *      12     usage error
  *      16     bad trouble
  */
+/*
+ * Copyright (C) 2000 Ian Jackson
+ *
+ * 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.
+ */
 
 #include <sys/socket.h>
 #include <netinet/in.h>
@@ -41,20 +66,19 @@
 #include <unistd.h>
 #include <fcntl.h>
 
-#include "mech.h"
+#include "forwarder.h"
 
 #define MAXMECHS 10
-#define PROGRAM "udptunnel-forwarder"
-char programid[SYS_NMLN+sizeof(PROGRAM)+3];
 
-static const char *const *argv;
 static size_t buffer_size;
+static struct utsname uname_result;
 
+static const char *opt_chars;
 static int public_local_fd, private_in_fd, private_out_fd;
-static int mtu2, keepalive, timeout;
+static int mtu2, keepalive, timeout, reannounce;
 static int public_remote_specd;
 static struct sockaddr_in public_remote;
-static int encdec_keys_fd, encdec_keys_write;
+static int encdec_keys_fd, encdec_keys_write, crypto_debug;
 static int n_mechs;
 static const struct mechanism *mechs[MAXMECHS];
 
@@ -67,41 +91,38 @@ static size_t accum_used, accum_avail;
 
 static time_t nextsendka;
 
-
-void arg_assert_fail(const char *msg) {
-  fprintf(stderr, PROGRAM ": argument error: %s\n",msg);
-  exit(12);
-}
-
-void sysfail(const char *msg) {
-  fprintf(stderr, "%s: fatal system error: %s: %s\n", programid, msg, strerror(errno));
-  exit(8);
-}
-
-void fail(const char *msg) {
-  fprintf(stderr, "%s: fatal error: %s\n", programid, msg);
-  exit(4);
+static void cdebug(int mechno /*or -1*/, const char *msg) {
+  if (!crypto_debug) return;
+  printf("%-8.8s: CRYPTO: %-20s %s\n",
+	 uname_result.nodename,
+	 mechno >= 0 ? mechs[mechno]->name : "",
+	 msg);
 }
 
-void sysdiag(const char *msg) {
-  fprintf(stderr, "%s: system/network error: %s: %s\n", programid, msg, strerror(errno));
-}
+static void cdebughex(int mechno /*or -1*/, const char *msg, const void *ptr,
+		      size_t sz, size_t skipbefore,
+		      int spc_offset, int dot_offset) {
+  const unsigned char *p;
+  size_t i;
+  unsigned j= dot_offset;
+  
+  if (!crypto_debug) return;
+  printf("%-8.8s: CRYPTO: %-20s %-10s",
+	 uname_result.nodename,
+	 mechno >= 0 ? mechs[mechno]->name : "",
+	 msg);
 
-void diag(const char *msg) {
-  fprintf(stderr, "%s: %s\n", programid, msg);
-}
+  for (i=0; i<spc_offset; i++, j++) fputs(j&3 ? "  " : "   ",stdout);
+  for (i=0; i<skipbefore; i++, j++) fputs(j&3 ? ".." : " ..",stdout);
+  for (i=0, p=ptr; i<sz; i++, j++, p++) printf(j&3 ? "%02x" : " %02x",*p);
 
-time_t now(void) {
-  time_t r;
-  if (time(&r) == (time_t)-1) sysfail("get time of day");
-  return r;
+  fputc('\n',stdout);
 }
 
-void *xmalloc(size_t sz) {
-  void *r;
-  r= malloc(sz);
-  if (!r) sysfail("allocate memory");
-  return r;
+static void cdebugbuf(int mechno /*or -1*/, const char *msg,
+		      const struct buffer *buf, int spc_offset, int dot_offset) {
+  cdebughex(mechno, msg, buf->start, buf->size, buf->start - buf->base,
+	    spc_offset, dot_offset);
 }
 
 void get_random(void *ptr, size_t sz) {
@@ -116,27 +137,23 @@ void get_random(void *ptr, size_t sz) {
   }
 
   r= fread(ptr,1,sz,randfile);
-  if (r == sz) return;
-  (ferror(randfile) ? sysfail : fail)("cannot read random number generator");
-}
+  if (r != sz)
+    (ferror(randfile) ? sysfail : fail)("cannot read random number generator");
 
-const char *getarg_string(void) {
-  const char *arg;
-  
-  arg= *++argv;
-  arg_assert(arg);
-  return arg;
+  cdebughex(-1, "get_random", ptr, sz, 0,0,0);
 }
 
-unsigned long getarg_ulong(void) {
-  char *ep;
-  unsigned long ul;
-  
-  ul= strtoul(getarg_string(),&ep,0);
-  arg_assert(!*ep);
-  return ul;
+void random_key(void *ptr, size_t sz) {
+  if (encdec_keys_write) {
+    get_random(ptr,sz);
+    write_must(encdec_keys_fd,ptr,sz,"write keys datastream");
+  } else {
+    read_must(encdec_keys_fd,ptr,sz,"read keys datastream");
+    cdebughex(-1, "random_key", ptr, sz, 0,0,0);
+  }
 }
 
+
 static void setnonblock(int fd, int nonblock) {
   int r;
   
@@ -146,12 +163,9 @@ static void setnonblock(int fd, int nonblock) {
   if (r==-1) sysfail("fcntl F_SETFL");
 }
 
-static const struct mechanism *getarg_mech(void) {
-  const char *name;
+static const struct mechanism *find_mech(const char *name) {
   const struct mechanism *mech, *const *mechlist;
 
-  name= getarg_string();
-
   for (mechlist= mechanismlists;
        *mechlist;
        mechlist++)
@@ -164,55 +178,69 @@ static const struct mechanism *getarg_mech(void) {
 
 static void inbound(void) {
   static int any_recvd;
+  static time_t nextreann;
+  static unsigned long npackets, nbytes;
   
   struct sockaddr_in this_saddr;
   int r, i, different, this_saddrlen;
   const char *emsg;
 
-  alarm(timeout);
-
+  buf_in.start= buf_in.base+1;
+  buf_in.size= buffer_size-2;
+  
   setnonblock(public_local_fd,1);
   this_saddrlen= sizeof(this_saddr);
-  r= recvfrom(public_local_fd, buf_in.base, buffer_size-1, 0,
+  r= recvfrom(public_local_fd, buf_in.start, buf_in.size, 0,
 	      &this_saddr, &this_saddrlen);
   if (!r) { diag("empty ciphertext"); return; }
 
   if (r<0) {
-    if (errno != EAGAIN && errno != EINTR) sysdiag("receive");
+    if (errno != EAGAIN && errno != EINTR) { sysdiag("receive"); sleep(1); }
     return;
   }
   if (this_saddr.sin_family != AF_INET) {
-    fprintf(stderr,"%s: received unknown AF %lu",
+    fprintf(stderr,"%s: received unknown AF %lu\n",
 	    programid, (unsigned long)this_saddr.sin_family);
     return;
   }
   assert(this_saddrlen == sizeof(this_saddr));
 
-  buf_in.size= buffer_size;
-  buf_in.start= buf_in.base;
+  assert(r <= buf_in.size);
+  buf_in.size= r;
+  cdebugbuf(-1, "decode", &buf_in, 3,0);
   for (i=n_mechs-1; i>=0; i--) {
     emsg= mechs[i]->decode(md_in[i],&buf_in);
     if (emsg) {
-      fprintf(stderr, "%s: bad packet: %s: %s\n", programid, mechs[i]->name, emsg);
+      if (*emsg)
+	fprintf(stderr, "%s: bad packet: %s: %s\n",
+		programid, mechs[i]->name, emsg);
+      else
+	cdebug(i,"silently discarded");
       return;
     }
+    cdebugbuf(i, "decode", &buf_in, 3,0);
   }
 
-  different= !public_remote_specd ||
-    memcmp(&this_saddr,&public_remote,sizeof(this_saddr));
+  npackets++;
+  nbytes += buf_in.size;
+  alarm(timeout);
+
+  different= (!public_remote_specd ||
+	      public_remote.sin_addr.s_addr != this_saddr.sin_addr.s_addr ||
+	      public_remote.sin_port != this_saddr.sin_port);
 
   if (different) {
 
     if (public_remote_specd==2) {
-      fprintf(stderr, "%s: packet from unexpected sender %s:%lu",
+      fprintf(stderr, "%s: packet from unexpected sender %s:%lu\n",
 	      programid, inet_ntoa(this_saddr.sin_addr),
-	      (unsigned long)this_saddr.sin_port);
+	      (unsigned long)ntohs(this_saddr.sin_port));
       return;
     }
 
-    fprintf(stderr, "%s: tunnel open with peer %s:%lu",
+    fprintf(stderr, "%s: tunnel open with peer %s:%lu\n",
 	    programid, inet_ntoa(this_saddr.sin_addr),
-	    (unsigned long)this_saddr.sin_port);
+	    (unsigned long)ntohs(this_saddr.sin_port));
     nextsendka= now();
     public_remote_specd= 1;
     memcpy(&public_remote,&this_saddr,sizeof(public_remote));
@@ -221,25 +249,34 @@ static void inbound(void) {
 
     diag("tunnel open");
 
+  } else if (reannounce && now() >= nextreann) {
+
+    fprintf(stderr, "%s: tunnel still open: received %lu packets, %lu bytes\n",
+	    programid, npackets, nbytes);
+
+  } else {
+
+    goto no_set_reann; /* only reset this if we don't print a message. */
+
   }
 
-  any_recvd= 1;
+  if (reannounce)
+    nextreann= now() + reannounce;
   
-  buf_in.start[buf_in.size]= 0300;
-  *--buf_in.start= 0300;
-  buf_in.size+= 2;
+no_set_reann:
 
-  setnonblock(private_in_fd,0);
-  while (buf_in.size) {
-    r= write(private_in_fd, buf_in.start, buf_in.size);
-    assert(r && r <= buf_in.size);
-    if (r<0) {
-      if (errno == EINTR) continue;
-      sysfail("write down");
-    }
-    buf_in.start += r;
-    buf_in.size -= r;
+  any_recvd= 1;
+
+  if (!buf_in.size || *buf_in.start != 0300) {
+    *--buf_in.start= 0300;
+    buf_in.size++;
   }
+  if (buf_in.start[buf_in.size-1] != 0300) {
+    buf_in.start[buf_in.size++]= 0300;
+  }
+
+  setnonblock(private_in_fd,0);
+  write_must(private_in_fd, buf_in.start, buf_in.size, "write down");
 }
 
 static void sendpacket(const unsigned char *message, size_t size) {
@@ -251,7 +288,11 @@ static void sendpacket(const unsigned char *message, size_t size) {
 
   nextsendka= now() + keepalive;
 
-  for (i=0; i<n_mechs; i++) mechs[i]->encode(md_out[i],&buf_out);
+  cdebugbuf(-1, "encode", &buf_out, 4,0);
+  for (i=0; i<n_mechs; i++) {
+    mechs[i]->encode(md_out[i],&buf_out);
+    cdebugbuf(i, "encode", &buf_out, 4,0);
+  }
   assert(public_remote_specd);
   
   setnonblock(public_local_fd,1);
@@ -284,7 +325,7 @@ static void outbound(void) {
     after_eaten= accum_buf;
     while ((delim= memchr(after_eaten, 0300, accum_used))) {
       this_packet= delim - after_eaten;
-      sendpacket(after_eaten, this_packet);
+      if (this_packet) sendpacket(after_eaten, this_packet);
       accum_used -= this_packet+1;
       after_eaten = delim+1;
     }
@@ -299,8 +340,9 @@ static void outbound(void) {
 
 int main(int argc, const char *const *const argv_in) {
   const char *arg;
+  const char *const *argv_save;
+  const char *const *argv_done;
   struct pollfd pollfds[2];
-  struct utsname uname_result;
   int i, polltimeout, r;
   time_t tnow;
 
@@ -308,28 +350,63 @@ int main(int argc, const char *const *const argv_in) {
 
   if (uname(&uname_result)) { perror(PROGRAM ": uname failed"); exit(16); }
   sprintf(programid, PROGRAM ": %.*s", SYS_NMLN, uname_result.nodename);
-  
+
+  opt_chars= getarg_string();
+  encdec_keys_write= !!strchr(opt_chars,'w');
+  crypto_debug= !!strchr(opt_chars,'K');
+
   public_local_fd= getarg_ulong();
+  private_in_fd= getarg_ulong();
+  private_out_fd= getarg_ulong();
+  encdec_keys_fd= getarg_ulong();
+
   mtu2= getarg_ulong() * 2;
   keepalive= getarg_ulong();
   timeout= getarg_ulong();
-  private_in_fd= getarg_ulong();
-  private_out_fd= getarg_ulong();
+  reannounce= getarg_ulong();
   
   arg= getarg_string();
   if (*arg) {
     public_remote_specd= 1;
+    public_remote.sin_family= AF_INET;
     arg_assert(inet_aton(arg,&public_remote.sin_addr));
-    public_remote.sin_port= getarg_ulong();
+    public_remote.sin_port= htons(getarg_ulong());
   }
 
-  encdec_keys_fd= getarg_ulong();
-  encdec_keys_write= !!*getarg_string();
+  if (crypto_debug) {
+    diag("crypto debugging enabled!");
+    setvbuf(stdout,0,_IOLBF,0);
+  }
 
   maxprefix= 0;
-  for (i=0; i<n_mechs; i++) mechs[i]= getarg_mech();
-  for (i=0; i<n_mechs; i++) mechs[i]->encsetup(&md_in[i], &maxprefix, &maxsuffix);
-  for (i=0; i<n_mechs; i++) mechs[i]->decsetup(&md_out[i]);
+  i= 0;
+  while ((arg= *++argv)) {
+    arg_assert(*arg++ == '|');
+    arg_assert(i <= MAXMECHS);
+    mechs[i]= find_mech(arg);
+
+    cdebug(i,"writer->reader setup");
+    argv_save= argv;
+
+    if (encdec_keys_write)
+      mechs[i]->encsetup(&md_out[i], &maxprefix, &maxsuffix);
+    else
+      mechs[i]->decsetup(&md_in[i]);
+
+    argv_done= argv;
+    argv= argv_save;
+    cdebug(i,"reader->writer setup");
+
+    if (encdec_keys_write)
+      mechs[i]->decsetup(&md_in[i]);
+    else
+      mechs[i]->encsetup(&md_out[i], &maxprefix, &maxsuffix);
+
+    assert(argv == argv_done);
+    
+    i++;
+  }
+  n_mechs= i;
 
   if (maxprefix<1) maxprefix= 1;
   if (maxsuffix<1) maxsuffix= 1;
@@ -351,7 +428,7 @@ int main(int argc, const char *const *const argv_in) {
 
     if (keepalive) {
       tnow= now();
-      if (tnow >= nextsendka) sendpacket("\300",1);
+      if (tnow >= nextsendka && public_remote_specd) sendpacket("\300",1);
       polltimeout= (nextsendka - tnow)*1000;
     } else {
       polltimeout= -1;
@@ -362,7 +439,7 @@ int main(int argc, const char *const *const argv_in) {
     if (r==-1 && errno==EINTR) continue;
     if (r==-1) sysfail("poll");
 
-    if (pollfds[0].revents & POLLIN) inbound();
-    if (pollfds[1].revents & POLLOUT) outbound();
+    if (pollfds[0].revents & (POLLIN|POLLERR)) inbound();
+    if (pollfds[1].revents & (POLLIN|POLLERR)) outbound();
   }
 }