X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/tripe/blobdiff_plain/66196407325756702eaa7ee25384d9b2374ed540..067aa5f013dd6108e81c1df0c2ed19491802bc69:/server/peer.c

diff --git a/server/peer.c b/server/peer.c
index 68e32e58..606b2038 100644
--- a/server/peer.c
+++ b/server/peer.c
@@ -9,19 +9,18 @@
  *
  * This file is part of Trivial IP Encryption (TrIPE).
  *
- * TrIPE 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.
+ * TrIPE 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.
  *
- * TrIPE 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.
+ * TrIPE 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 TrIPE; if not, write to the Free Software Foundation,
- * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with TrIPE.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 /*----- Header files ------------------------------------------------------*/
@@ -167,6 +166,51 @@ static int p_encrypt(peer *p, int ty, buf *bin, buf *bout)
   return (err);
 }
 
+/* --- @p_updateaddr@ --- *
+ *
+ * Arguments:	@peer *p@ = pointer to peer block
+ *		@const addr *a@ = address to associate with this peer
+ *
+ * Returns:	Zero if the address was changed; @+1@ if it was already
+ *		right.
+ *
+ * Use:		Updates our idea of @p@'s address.
+ */
+
+int p_updateaddr(peer *p, const addr *a)
+{
+  peer *q;
+  peer_byaddr *pa, *qa;
+  unsigned f;
+
+  /* --- Figure out how to proceed --- *
+   *
+   * If this address already belongs to a different peer, then swap the
+   * addresses over.  This doesn't leave the displaced peer in an especially
+   * good state, but it ought to get sorted out soon enough.
+   */
+
+  pa = am_find(&byaddr, a, sizeof(peer_byaddr), &f);
+  if (f && pa->p == p)
+    return (+1);
+  else if (!f) {
+    T( trace(T_PEER, "peer: updating address for `%s'", p_name(p)); )
+    am_remove(&byaddr, p->byaddr);
+    p->byaddr = pa; p->spec.sa = *a; pa->p = p;
+    a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
+    return (0);
+  } else {
+    q = pa->p; qa = p->byaddr;
+    T( trace(T_PEER, "peer: swapping addresses for `%s' and `%s'",
+	     p_name(p), p_name(q)); )
+    q->byaddr = qa; qa->p = q; q->spec.sa = p->spec.sa;
+    p->byaddr = pa; pa->p = p; p->spec.sa = *a;
+    a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
+    a_notify("NEWADDR", "?PEER", q, "?ADDR", &q->spec.sa, A_END);
+    return (0);
+  }
+}
+
 /* --- @p_decrypt@ --- *
  *
  * Arguments:	@peer **pp@ = pointer to peer to decrypt message from
@@ -188,55 +232,74 @@ static int p_encrypt(peer *p, int ty, buf *bin, buf *bout)
 static int p_decrypt(peer **pp, addr *a, size_t n,
 		     int ty, buf *bin, buf *bout)
 {
-  peer *p;
-  peer_byaddr *pa;
+  peer *p, *q;
   int err = KSERR_DECRYPT;
-  unsigned f;
 
-  if (*pp) {
-    p = *pp;
+  /* --- If we have a match on the source address then try that first --- */
+
+  q = *pp;
+  if (q) {
     T( trace(T_PEER, "peer: decrypting packet from known peer `%s'",
-	     p_name(p)); )
-    err = ksl_decrypt(&p->ks, ty, bin, bout);
-  } else {
+	     p_name(q)); )
+    if ((err = ksl_decrypt(&q->ks, ty, bin, bout)) != KSERR_DECRYPT ||
+	!(q->spec.f & PSF_MOBILE) || nmobile == 1) {
+      p = q;
+      goto match;
+    }
+    T( trace(T_PEER, "peer: failed to decrypt: try other mobile peers..."); )
+  } else if (nmobile)
+    T( trace(T_PEER, "peer: unknown source: trying mobile peers...") );
+  else {
     p = 0;
-    if (nmobile) {
-      T( trace(T_PEER, "peer: unknown source: trying mobile peers..."); )
-      FOREACH_PEER(q, {
-	if (!(q->spec.f & PSF_MOBILE)) continue;
-	if ((err = ksl_decrypt(&q->ks, ty, bin, bout)) == KSERR_DECRYPT) {
-	  T( trace(T_PEER, "peer: peer `%s' failed to decrypt",
-		   p_name(q)); )
-	  continue;
-	} else {
-	  p = *pp = q;
-	  IF_TRACING(T_PEER, {
-	    if (!err)
-	      trace(T_PEER, "peer: peer `%s' reports success", p_name(p));
-	    else {
-	      trace(T_PEER, "peer: peer `%s' reports decryption error %d",
-		    p_name(p), err);
-	    }
-	  })
-	  break;
+    goto searched;
+  }
+
+  /* --- See whether any mobile peer is interested --- */
+
+  p = 0;
+  FOREACH_PEER(qq, {
+    if (qq == q || !(qq->spec.f & PSF_MOBILE)) continue;
+    if ((err = ksl_decrypt(&qq->ks, ty, bin, bout)) == KSERR_DECRYPT) {
+      T( trace(T_PEER, "peer: peer `%s' failed to decrypt",
+	       p_name(qq)); )
+	continue;
+    } else {
+      p = qq;
+      IF_TRACING(T_PEER, {
+	if (!err)
+	  trace(T_PEER, "peer: peer `%s' reports success", p_name(qq));
+	else {
+	  trace(T_PEER, "peer: peer `%s' reports decryption error %d",
+		p_name(qq), err);
 	}
-      });
+      })
+      break;
     }
-    if (!p) {
+  });
+
+  /* --- We've searched the mobile peers --- */
+
+searched:
+  if (!p) {
+    if (!q)
       a_warn("PEER", "-", "unexpected-source", "?ADDR", a, A_END);
-      return (-1);
-    }
-    if (!err) {
-      T( trace(T_PEER, "peer: updating address for `%s'", p_name(p)); )
-      p_rxupdstats(p, n);
-      pa = am_find(&byaddr, a, sizeof(peer_byaddr), &f); assert(!f);
-      am_remove(&byaddr, p->byaddr);
-      p->byaddr = pa;
-      pa->p = p;
-      p->spec.sa = *a;
-      a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
+    else {
+      a_warn("PEER", "?PEER", p, "decrypt-failed",
+	     "error-code", "%d", err, A_END);
+      p_rxupdstats(q, n);
     }
+    return (-1);
+  }
+
+  /* --- We found one that accepted, so update the peer's address --- */
+
+  if (!err) {
+    *pp = p;
+    p_updateaddr(p, a);
   }
+
+match:
+  p_rxupdstats(p, n);
   if (err) {
     if (p) p->st.n_reject++;
     a_warn("PEER", "?PEER", p, "decrypt-failed",
@@ -263,14 +326,14 @@ static void p_read(int fd, unsigned mode, void *v)
 {
   peer *p = 0;
   addr a;
-  size_t sz;
+  socklen_t sz;
   ssize_t n;
   int ch;
   buf b, bb;
 
   /* --- Read the data --- */
 
-  TIMER;
+  QUICKRAND;
   sz = sizeof(addr);
   n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz);
   if (n < 0) {
@@ -289,7 +352,7 @@ static void p_read(int fd, unsigned mode, void *v)
     })
     buf_init(&b, buf_i, n);
     buf_getbyte(&b);
-    if (c_check(&b) || BLEFT(&b)) {
+    if (c_check(0, 0, &b) || BLEFT(&b)) {
       a_warn("PEER", "-", "invalid-greeting", A_END);
       return;
     }
@@ -321,7 +384,6 @@ static void p_read(int fd, unsigned mode, void *v)
 
   /* --- Pick the packet apart --- */
 
-  if (p) p_rxupdstats(p, n);
   buf_init(&b, buf_i, n);
   if ((ch = buf_getbyte(&b)) < 0) {
     a_warn("PEER", "?PEER", p, "bad-packet", "no-type", A_END);
@@ -351,22 +413,25 @@ static void p_read(int fd, unsigned mode, void *v)
       }
       break;
     case MSG_KEYEXCH:
-      if (!p) goto unexp;
-      kx_message(&p->kx, ch & MSG_TYPEMASK, &b);
+      if (p) p_rxupdstats(p, n);
+      if (kx_message(p ? &p->kx : 0, &a, ch & MSG_TYPEMASK, &b)) goto unexp;
       break;
     case MSG_MISC:
       switch (ch & MSG_TYPEMASK) {
 	case MISC_NOP:
 	  if (!p) goto unexp;
+	  p_rxupdstats(p, n);
 	  T( trace(T_PEER, "peer: received NOP packet"); )
 	  break;
 	case MISC_PING:
 	  if (!p) goto unexp;
+	  p_rxupdstats(p, n);
 	  buf_put(p_txstart(p, MSG_MISC | MISC_PONG), BCUR(&b), BLEFT(&b));
 	  p_txend(p);
 	  break;
 	case MISC_PONG:
 	  if (!p) goto unexp;
+	  p_rxupdstats(p, n);
 	  p_ponged(p, MISC_PONG, &b);
 	  break;
 	case MISC_EPING:
@@ -389,6 +454,16 @@ static void p_read(int fd, unsigned mode, void *v)
 	    p_ponged(p, MISC_EPONG, &bb);
 	  }
 	  break;
+	case MISC_BYE:
+	  buf_init(&bb, buf_t, sizeof(buf_t));
+	  if (p_decrypt(&p, &a, n, ch, &b, &bb)) return;
+	  if (!(p->spec.f&PSF_EPHEM)) return;
+	  if (BOK(&bb)) {
+	    buf_flip(&bb);
+	    if (BSZ(&bb)) return;
+	    p_destroy(p, 0);
+	  }
+	  break;
       }
       break;
     default:
@@ -423,6 +498,30 @@ buf *p_txstart(peer *p, unsigned msg)
   return (&p->b);
 }
 
+/* --- @p_txaddr@ --- *
+ *
+ * Arguments:	@const addr *a@ = recipient address
+ *		@const void *p@ = pointer to packet to send
+ *		@size_t sz@ = length of packet
+ *
+ * Returns:	Zero if successful, nonzero on error.
+ *
+ * Use:		Sends a packet to an address which (possibly) isn't a current
+ *		peer.
+ */
+
+int p_txaddr(const addr *a, const void *p, size_t sz)
+{
+  socklen_t sasz = addrsz(a);
+
+  IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet", p, sz); )
+  if (sendto(sock.fd, p, sz, 0, &a->sa, sasz) < 0) {
+    a_warn("PEER", "?ADDR", a, "socket-write-error", "?ERRNO", A_END);
+    return (-1);
+  }
+  return (0);
+}
+
 /* --- @p_txend@ --- *
  *
  * Arguments:	@peer *p@ = pointer to peer block
@@ -436,6 +535,8 @@ static void p_setkatimer(peer *);
 
 static int p_dotxend(peer *p)
 {
+  socklen_t sasz = addrsz(&p->spec.sa);
+
   if (!BOK(&p->b)) {
     a_warn("PEER", "?PEER", p, "packet-build-failed", A_END);
     return (0);
@@ -443,7 +544,7 @@ static int p_dotxend(peer *p)
   IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet",
 				 BBASE(&p->b), BLEN(&p->b)); )
   if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b),
-	     0, &p->spec.sa.sa, p->spec.sasz) < 0) {
+	     0, &p->spec.sa.sa, sasz) < 0) {
     a_warn("PEER", "?PEER", p, "socket-write-error", "?ERRNO", A_END);
     return (0);
   } else {
@@ -612,7 +713,7 @@ void p_tun(peer *p, buf *b)
 {
   buf *bb = p_txstart(p, MSG_PACKET);
 
-  TIMER;
+  QUICKRAND;
   p_encrypt(p, MSG_PACKET, b, bb);
   if (BOK(bb) && BLEN(bb)) {
     p->st.n_ipout++;
@@ -752,7 +853,7 @@ void p_init(struct in_addr addr, unsigned port)
 unsigned p_port(void)
 {
   addr a;
-  size_t sz = sizeof(addr);
+  socklen_t sz = sizeof(addr);
 
   if (getsockname(sock.fd, &a.sa, &sz))
     die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno));
@@ -773,6 +874,7 @@ unsigned p_port(void)
 static void p_keepalive(struct timeval *now, void *pv)
 {
   peer *p = pv;
+
   p_txstart(p, MSG_MISC | MISC_NOP); p_dotxend(p);
   T( trace(T_PEER, "peer: sent keepalive to %s", p->spec.name); )
   p_setkatimer(p);
@@ -824,8 +926,9 @@ peer *p_create(peerspec *spec)
   T( trace(T_PEER, "peer: creating new peer `%s'", spec->name); )
   p->spec = *spec;
   p->spec.name = (/*unconst*/ char *)SYM_NAME(p->byname);
-  if (spec->tag)
-    p->spec.tag = xstrdup(spec->tag);
+  if (spec->tag) p->spec.tag = xstrdup(spec->tag);
+  if (spec->privtag) p->spec.privtag = xstrdup(spec->privtag);
+  if (spec->knock) p->spec.knock = xstrdup(spec->knock);
   p->ks = 0;
   p->pings = 0;
   p->ifname = 0;
@@ -840,7 +943,7 @@ peer *p_create(peerspec *spec)
   T( trace(T_TUNNEL, "peer: attached interface %s to peer `%s'",
 	   p->ifname, p_name(p)); )
   p_setkatimer(p);
-  if (kx_init(&p->kx, p, &p->ks, p->spec.f & PSF_KXMASK))
+  if (kx_setup(&p->kx, p, &p->ks, p->spec.f & PSF_KXMASK))
     goto tidy_4;
   a_notify("ADD",
 	   "?PEER", p,
@@ -855,8 +958,7 @@ peer *p_create(peerspec *spec)
   return (p);
 
 tidy_4:
-  if (spec->t_ka)
-    sel_rmtimer(&p->tka);
+  if (spec->t_ka) sel_rmtimer(&p->tka);
   xfree(p->ifname);
   p->t->ops->destroy(p->t);
 tidy_3:
@@ -864,6 +966,7 @@ tidy_3:
 tidy_2:
   am_remove(&byaddr, p->byaddr);
   if (p->spec.tag) xfree(p->spec.tag);
+  if (p->spec.privtag) xfree(p->spec.privtag);
 tidy_1:
   sym_remove(&byname, p->byname);
 tidy_0:
@@ -891,6 +994,16 @@ const char *p_name(peer *p)
 const char *p_tag(peer *p)
   { return (p->spec.tag ? p->spec.tag : p->spec.name); }
 
+/* --- @p_privtag@ --- *
+ *
+ * Arguments:	@peer *p@ = pointer to a peer block
+ *
+ * Returns:	A pointer to the peer's private key tag.
+ */
+
+const char *p_privtag(peer *p)
+  { return (p->spec.privtag ? p->spec.privtag : tag_priv); }
+
 /* --- @p_spec@ --- *
  *
  * Arguments:	@peer *p@ = pointer to a peer block
@@ -941,29 +1054,38 @@ peer *p_find(const char *name)
 /* --- @p_destroy@ --- *
  *
  * Arguments:	@peer *p@ = pointer to a peer
+ *		@int bye@ = say goodbye to the peer?
  *
  * Returns:	---
  *
  * Use:		Destroys a peer.
  */
 
-void p_destroy(peer *p)
+void p_destroy(peer *p, int bye)
 {
   ping *pg, *ppg;
+  buf *b, bb;
 
   T( trace(T_PEER, "peer: destroying peer `%s'", p->spec.name); )
+
+  if (bye && (p->spec.f&PSF_EPHEM)) {
+    b = p_txstart(p, MSG_MISC | MISC_BYE);
+    buf_init(&bb, buf_t, sizeof(buf_t));
+    assert(BOK(&bb)); buf_flip(&bb);
+    p_encrypt(p, MSG_MISC | MISC_BYE, &bb, b);
+    p_txend(p);
+  }
+
   a_notify("KILL", "%s", p->spec.name, A_END);
   ksl_free(&p->ks);
   kx_free(&p->kx);
-  if (p->spec.f & PSF_MOBILE)
-    nmobile--;
-  if (p->ifname)
-    xfree(p->ifname);
-  if (p->spec.tag)
-    xfree(p->spec.tag);
+  if (p->spec.f & PSF_MOBILE) nmobile--;
+  if (p->ifname) xfree(p->ifname);
+  if (p->spec.tag) xfree(p->spec.tag);
+  if (p->spec.privtag) xfree(p->spec.privtag);
+  if (p->spec.knock) xfree(p->spec.knock);
   p->t->ops->destroy(p->t);
-  if (p->spec.t_ka)
-    sel_rmtimer(&p->tka);
+  if (p->spec.t_ka) sel_rmtimer(&p->tka);
   for (pg = p->pings; pg; pg = ppg) {
     ppg = pg->next;
     p_pingdone(pg, PING_PEERDIED);