server/peer.c: Handle mobile peers switching addresses.

[tripe] / server / peer.c

diff --git a/server/peer.c b/server/peer.c
index 68e32e58de87bab89701e622af59b4c9e2bb6cb0..02fceed5b423096972d6b8e7c43e4fae614ad54c 100644 (file)
--- a/server/peer.c
+++ b/server/peer.c
@@ -188,55 +188,91 @@ 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;
+  peer_byaddr *pa, *qa;
   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...",
+            p_name(q)); )
+  } 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 --- */
+
+  FOREACH_PEER(pp, {
+    if (pp == q || !(pp->spec.f & PSF_MOBILE)) continue;
+    if ((err = ksl_decrypt(&pp->ks, ty, bin, bout)) == KSERR_DECRYPT) {
+      T( trace(T_PEER, "peer: peer `%s' failed to decrypt",
+              p_name(pp)); )
+       continue;
+    } else {
+      p = pp;
+      IF_TRACING(T_PEER, {
+       if (!err)
+         trace(T_PEER, "peer: peer `%s' reports success", p_name(pp));
+       else {
+         trace(T_PEER, "peer: peer `%s' reports decryption error %d",
+               p_name(pp), err);
        }
-      });
-    }
-    if (!p) {
-      a_warn("PEER", "-", "unexpected-source", "?ADDR", a, A_END);
-      return (-1);
+      })
+      break;
     }
-    if (!err) {
+  });
+
+  /* --- We've searched the mobile peers --- */
+
+searched:
+  if (!p) {
+    a_warn("PEER", "-", "unexpected-source", "?ADDR", a, A_END);
+    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) {
+    if (!q) {
       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 {
+      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",
@@ -321,7 +357,6 @@ 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);
@@ -352,21 +387,25 @@ 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: