X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/tripe/blobdiff_plain/388e0319a0faf48193658c82228133bd1ea24eb6..11ad66c29764521f87f0dd399a1e592147c7af36:/server/peer.c

diff --git a/server/peer.c b/server/peer.c
index 4bb2c82c..f74b977d 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 ------------------------------------------------------*/
@@ -33,6 +32,7 @@
 static sym_table byname;
 static addrmap byaddr;
 static sel_file sock;
+static unsigned nmobile;
 
 /*----- Tunnel table ------------------------------------------------------*/
 
@@ -122,6 +122,23 @@ found:
   p_pingdone(pg, PING_OK);
 }
 
+/* --- @p_rxupdstats@ --- *
+ *
+ * Arguments:	@peer *p@ = peer to update
+ *		@size_t n@ = size of incoming packet
+ *
+ * Returns:	---
+ *
+ * Use:		Updates the peer's incoming packet statistics.
+ */
+
+static void p_rxupdstats(peer *p, size_t n)
+{
+  p->st.t_last = time(0);
+  p->st.n_in++;
+  p->st.sz_in += n;
+}
+
 /* --- @p_encrypt@ --- *
  *
  * Arguments:	@peer *p@ = peer to encrypt message to
@@ -151,7 +168,9 @@ static int p_encrypt(peer *p, int ty, buf *bin, buf *bout)
 
 /* --- @p_decrypt@ --- *
  *
- * Arguments:	@peer *p@ = peer to decrypt message from
+ * Arguments:	@peer **pp@ = pointer to peer to decrypt message from
+ *		@addr *a@ = address the packet arrived on
+ *		@size_t n@ = size of original incoming packet
  *		@int ty@ = message type to expect
  *		@buf *bin, *bout@ = input and output buffers
  *
@@ -159,13 +178,111 @@ static int p_encrypt(peer *p, int ty, buf *bin, buf *bout)
  *
  * Use:		Convenience function for packet decryption.  Reports errors
  *		and updates statistics appropriately.
+ *
+ *		If @*pp@ is null on entry and there are mobile peers then we
+ *		see if any of them can decrypt the packet.  If so, we record
+ *		@*a@ as the peer's new address and send a notification.
  */
 
-static int p_decrypt(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)
 {
-  if (ksl_decrypt(&p->ks, ty, bin, bout)) {
-    p->st.n_reject++;
-    a_warn("PEER", "?PEER", p, "decrypt-failed", A_END);
+  peer *p, *q;
+  peer_byaddr *pa, *qa;
+  int err = KSERR_DECRYPT;
+  unsigned f;
+
+  /* --- 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(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;
+    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;
+    }
+  });
+
+  /* --- We've searched the mobile peers --- */
+
+searched:
+  if (!p) {
+    if (!q)
+      a_warn("PEER", "-", "unexpected-source", "?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 we had an initial guess of which peer this packet came from -- i.e.,
+   * @q@ is not null -- then swap the addresses over.  This doesn't leave the
+   * evicted peer in an especially good state, but it ought to get sorted out
+   * soon enough.
+   */
+
+  if (!err) {
+    *pp = p;
+    if (!q) {
+      T( trace(T_PEER, "peer: updating address for `%s'", p_name(p)); )
+      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 {
+      T( trace(T_PEER, "peer: swapping addresses for `%s' and `%s'",
+	       p_name(p), p_name(q)); )
+      pa = p->byaddr; qa = q->byaddr;
+      pa->p = q; q->byaddr = pa; q->spec.sa = p->spec.sa;
+      qa->p = p; p->byaddr = qa; p->spec.sa = *a;
+      a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
+      a_notify("NEWADDR", "?PEER", q, "?ADDR", &q->spec.sa, A_END);
+    }
+  }
+
+match:
+  p_rxupdstats(p, n);
+  if (err) {
+    if (p) p->st.n_reject++;
+    a_warn("PEER", "?PEER", p, "decrypt-failed",
+	   "error-code", "%d", err, A_END);
     return (-1);
   }
   if (!BOK(bout))
@@ -188,14 +305,14 @@ 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) {
@@ -225,23 +342,27 @@ static void p_read(int fd, unsigned mode, void *v)
     return;
   }
 
-  /* --- Find the appropriate peer --- */
+  /* --- Find the appropriate peer --- *
+   *
+   * At this stage, don't worry too much about whether we actually found it.
+   */
 
-  if ((p = p_findbyaddr(&a)) == 0) {
-    a_warn("PEER", "-", "unexpected-source", "?ADDR", &a, A_END);
-    return;
-  }
+  p = p_findbyaddr(&a);
 
   IF_TRACING(T_PEER, {
-    trace(T_PEER, "peer: packet received from `%s'", p->spec.name);
+    if (p) {
+      trace(T_PEER,
+	    "peer: packet received from `%s' from address INET %s %d",
+	    p_name(p), inet_ntoa(a.sin.sin_addr), ntohs(a.sin.sin_port));
+    } else {
+      trace(T_PEER, "peer: packet received from unknown address INET %s %d",
+	    inet_ntoa(a.sin.sin_addr), ntohs(a.sin.sin_port));
+    }
     trace_block(T_PACKET, "peer: packet contents", buf_i, n);
   })
 
   /* --- Pick the packet apart --- */
 
-  p->st.t_last = time(0);
-  p->st.n_in++;
-  p->st.sz_in += n;
   buf_init(&b, buf_i, n);
   if ((ch = buf_getbyte(&b)) < 0) {
     a_warn("PEER", "?PEER", p, "bad-packet", "no-type", A_END);
@@ -255,11 +376,11 @@ static void p_read(int fd, unsigned mode, void *v)
 	       "bad-packet",
 	       "unknown-type", "0x%02x", ch,
 	       A_END);
-	p->st.n_reject++;
+	if (p) p->st.n_reject++;
 	return;
       }
       buf_init(&bb, buf_o, sizeof(buf_o));
-      if (p_decrypt(p, MSG_PACKET, &b, &bb))
+      if (p_decrypt(&p, &a, n, MSG_PACKET, &b, &bb))
 	return;
       if (BOK(&bb)) {
 	p->st.n_ipin++;
@@ -271,23 +392,31 @@ static void p_read(int fd, unsigned mode, void *v)
       }
       break;
     case MSG_KEYEXCH:
+      if (!p) goto unexp;
+      p_rxupdstats(p, n);
       kx_message(&p->kx, ch & MSG_TYPEMASK, &b);
       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:
 	  buf_init(&bb, buf_t, sizeof(buf_t));
-	  if (p_decrypt(p, ch, &b, &bb))
+	  if (p_decrypt(&p, &a, n, ch, &b, &bb))
 	    return;
 	  if (BOK(&bb)) {
 	    buf_flip(&bb);
@@ -298,7 +427,7 @@ static void p_read(int fd, unsigned mode, void *v)
 	  break;
 	case MISC_EPONG:
 	  buf_init(&bb, buf_t, sizeof(buf_t));
-	  if (p_decrypt(p, ch, &b, &bb))
+	  if (p_decrypt(&p, &a, n, ch, &b, &bb))
 	    return;
 	  if (BOK(&bb)) {
 	    buf_flip(&bb);
@@ -308,13 +437,16 @@ static void p_read(int fd, unsigned mode, void *v)
       }
       break;
     default:
-      p->st.n_reject++;
+      if (p) p->st.n_reject++;
       a_warn("PEER",
 	     "?PEER", p,
 	     "bad-packet",
-	     "unknown-category" "0x%02x", ch,
+	     "unknown-category", "0x%02x", ch,
 	     A_END);
       break;
+    unexp:
+      a_warn("PEER", "-", "unexpected-source", "?ADDR", &a, A_END);
+      break;
   }
 }
 
@@ -525,7 +657,7 @@ 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++;
@@ -665,7 +797,7 @@ 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));
@@ -686,6 +818,7 @@ 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);
@@ -737,6 +870,8 @@ 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->privtag) p->spec.privtag = xstrdup(spec->privtag);
   p->ks = 0;
   p->pings = 0;
   p->ifname = 0;
@@ -751,28 +886,30 @@ 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.kxf))
+  if (kx_init(&p->kx, p, &p->ks, p->spec.f & PSF_KXMASK))
     goto tidy_4;
   a_notify("ADD",
 	   "?PEER", p,
 	   "%s", p->ifname,
 	   "?ADDR", &p->spec.sa,
 	   A_END);
-  if (!(p->spec.kxf & KXF_CORK)) {
+  if (!(p->spec.f & KXF_CORK)) {
     a_notify("KXSTART", "?PEER", p, A_END);
     /* Couldn't tell anyone before */
   }
+  if (p->spec.f & PSF_MOBILE) nmobile++;
   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:
   if (fd >= 0) close(fd);
 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:
@@ -787,7 +924,28 @@ tidy_0:
  * Returns:	A pointer to the peer's name.
  */
 
-const char *p_name(peer *p) { return (p->spec.name); }
+const char *p_name(peer *p)
+  { if (p) return (p->spec.name); else return ("-"); }
+
+/* --- @p_tag@ --- *
+ *
+ * Arguments:	@peer *p@ = pointer to a peer block
+ *
+ * Returns:	A pointer to the peer's public key tag.
+ */
+
+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@ --- *
  *
@@ -811,8 +969,10 @@ peer *p_findbyaddr(const addr *a)
 {
   peer_byaddr *pa;
 
-  if ((pa = am_find(&byaddr, a, 0, 0)) != 0)
+  if ((pa = am_find(&byaddr, a, 0, 0)) != 0) {
+    assert(pa->p);
     return (pa->p);
+  }
   return (0);
 }
 
@@ -851,11 +1011,12 @@ void p_destroy(peer *p)
   a_notify("KILL", "%s", p->spec.name, A_END);
   ksl_free(&p->ks);
   kx_free(&p->kx);
-  if (p->ifname)
-    xfree(p->ifname);
+  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);
   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);