X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/tripe/blobdiff_plain/10f681b1faa30ad9293a4fb87e6920142318f429..46401b81fe5fab9b0d3d3a5f5764bafa3f9c0b86:/server/tun-slip.c

diff --git a/server/tun-slip.c b/server/tun-slip.c
index d405cc49..c945998d 100644
--- a/server/tun-slip.c
+++ b/server/tun-slip.c
@@ -50,7 +50,9 @@ struct tunnel {
   unsigned st;				/* Current parser state */
 #   define ST_ESC 1u			/*   Last saw an escape character */
 #   define ST_BAD 2u			/*   This packet is malformed */
+#   define ST_MASK 3u			/*   Mask for the above bits */
 #   define ST_EOF 4u			/*   File descriptor reported EOF */
+#   define ST_BROKEN 8u			/*   Sending side is broken */
   size_t n;				/* Number of bytes used in buffer */
   octet buf[PKBUFSZ];			/* Buffer for incoming data */
 };
@@ -93,12 +95,13 @@ static void t_read(int fd, unsigned mode, void *v)
 #endif
 	errno == EAGAIN)
       return;
-    a_warn("TUN", "%s", p_ifname(t->p), "read-error", "?ERRNO", A_END);
+    a_warn("TUN", "%s", p_ifname(t->p), "slip",
+	   "read-error", "?ERRNO", A_END);
     return;
   }
   if (!n) {
     a_warn("TUN", "%s", p_ifname(t->p), "slip", "eof", A_END);
-    t->st = ST_EOF;
+    t->st = (t->st & ~ST_MASK) | ST_EOF;
     sel_rmfile(&t->f);
     return;
   }
@@ -118,9 +121,10 @@ static void t_read(int fd, unsigned mode, void *v)
       case SL_END:
 	if (st & ST_BAD)
 	  ;
-	else if (st & ST_ESC)
+	else if (st & ST_ESC) {
 	  a_warn("TUN", "%s", p_ifname(t->p), "slip", "escape-end", A_END);
-	else if (q == t->buf) {
+	  st |= ST_BAD;
+	} else if (q == t->buf) {
 	  T( trace(T_TUNNEL, "tun-slip: empty packet"); )
 	} else {
 	  IF_TRACING(T_TUNNEL, {
@@ -132,7 +136,7 @@ static void t_read(int fd, unsigned mode, void *v)
 	  p_tun(t->p, &b);
 	}
 	q = t->buf;
-	st &= ~(ST_ESC | ST_BAD);
+	st &= ~ST_MASK;
 	break;
       case SL_ESC:
 	if ((st & ST_ESC) && !(st & ST_BAD)) {
@@ -243,9 +247,33 @@ whine:
   moan("bad slip interface list");
 }
 
+/* --- @t_broken@ --- *
+ *
+ * Arguments:	@tunnel *t@ = pointer to the tunnel
+ *
+ * Returns:	---
+ *
+ * Use:		Marks the tunnel as broken and reports an error.
+ */
+
+static void t_broken(tunnel *t)
+{
+  if (errno == EINTR ||
+#if defined(EWOULDBLOCK) && EWOULDBLOCK != EAGAIN
+      errno == EWOULDBLOCK ||
+#endif
+      errno == EAGAIN)
+    return;
+  a_warn("TUN", "%s", p_ifname(t->p), "slip",
+	 "write-error", "?ERRNO", A_END);
+  T( trace(T_TUNNEL, "tun-slip: marking tunnel broken"); )
+  t->st |= ST_BROKEN;
+}
+
 /* --- @t_create@ --- *
  *
  * Arguments:	@peer *p@ = pointer to peer block
+ *		@int fd@ = file descriptor of tunnel device (unused)
  *		@char **ifn@ = where to put the interface name
  *
  * Returns:	A tunnel block if it worked, or null on failure.
@@ -253,10 +281,11 @@ whine:
  * Use:		Initializes a new tunnel.
  */
 
-static tunnel *t_create(peer *p, char **ifn)
+static tunnel *t_create(peer *p, int fd, char **ifn)
 {
   slipif *sl = 0;
   int pin[2] = { -1, -1 }, pout[2] = { -1, -1 };
+  mdup_fd md[2];
   pid_t kid = -1;
   dstr d = DSTR_INIT;
   unsigned char ch;
@@ -291,10 +320,10 @@ static tunnel *t_create(peer *p, char **ifn)
     goto fail;
   }
   if (!kid) {
-    close(pin[1]);
-    close(pout[0]);
-    dup2(pin[0], STDIN_FILENO);
-    dup2(pout[1], STDOUT_FILENO);
+    close(pin[1]); close(pout[0]);
+    md[0].cur = pin[0];  md[0].want = STDIN_FILENO;
+    md[1].cur = pout[1]; md[1].want = STDOUT_FILENO;
+    mdup(md, 2);
     execlp(slipcmd, slipcmd, p_name(p), (char *)0);
     _exit(127);
   }
@@ -338,7 +367,8 @@ found:
   sl->f |= F_INUSE;
   sel_initfile(&sel, &t->f, sl->ifd, SEL_READ, t_read, t);
   sel_addfile(&t->f);
-  write(sl->ofd, end, sizeof(end));
+  if (write(sl->ofd, end, sizeof(end)) < 0)
+    t_broken(t);
   *ifn = xstrdup(sl->name);
   dstr_destroy(&d);
   return (t);
@@ -390,6 +420,10 @@ static void t_inject(tunnel *t, buf *b)
     trace_block(T_PACKET, "tun-slip: packet contents", BBASE(b), BLEN(b));
   })
 
+  if (t-> st & ST_BROKEN) {
+    T( trace(T_TUNNEL, "tun-slip: tunnel broken; discarding"); )
+    return;
+  }
   q = buf;
   *q++ = SL_END;
   for (p = BBASE(b), l = BCUR(b); p < l; p++) {
@@ -404,7 +438,8 @@ static void t_inject(tunnel *t, buf *b)
     trace_block(T_PACKET, "tun-slip: SLIP-encapsulated contents",
 		buf, q - buf);
   })
-  write(t->sl->ofd, buf, q - buf);
+  if (write(t->sl->ofd, buf, q - buf) < 0)
+    t_broken(t);
 }
 
 /* --- @t_destroy@ --- *
@@ -439,6 +474,7 @@ static void t_destroy(tunnel *t)
 
 const tunnel_ops tun_slip = {
   "slip",
+  0,
   t_init,
   t_create,
   t_setifname,