Allow user control over autobinding. Also try ports at random to start

off with, falling back to linear search.

diff --git a/noip.1 b/noip.1
index 36b4cf0eae14f4e18ac61cbc6cdc7accc8db8220..d11ce7d78dcbfed25e377aea722c7199c0fac900 100644 (file)
--- a/noip.1
+++ b/noip.1
@@ -114,6 +114,16 @@ rather than the default.  The environment variable
 .B NOIP_SOCKETDIR
 can also be used to control which directory is used for sockets.
 .TP
+.BI "autoports " min "\-" max
+Select which ports are used for implicit binding.  Allocating ports can
+be a bit slow, since checking whether a Unix domain socket is in use is
+difficult.  A wide range makes things easier, because
+.B noip
+starts by trying ports at random from the given range.  The environment
+variable
+.B NOIP_AUTOPORTS
+can also be used to control which ports are assigned automatically.
+.TP
 .BI "realbind " acl-entry
 Add an entry to the
 .B realbind

diff --git a/noip.c b/noip.c
index 2f7fd148800057910f2cce63154760b96887acc2..61d4a627e382e18798dd952e45f177594edca661 100644 (file)
--- a/noip.c
+++ b/noip.c
@@ -42,6 +42,7 @@ static int n_local_ipaddrs;
 static uid_t uid;
 static char *sockdir = 0;
 static int debug = 0;
+static unsigned minautoport = 16384, maxautoport = 65536;
 
 static aclnode *bind_real, **bind_tail = &bind_real;
 static aclnode *connect_real,  **connect_tail = &connect_real;
@@ -218,6 +219,19 @@ static void dump_acl(aclnode *a)
 
 #endif
 
+static unsigned randrange(unsigned min, unsigned max)
+{
+  unsigned mask, i;
+
+  /* It's so nice not to have to care about the quality of the generator
+     much! */
+  max -= min;
+  for (mask = 1; mask < max; mask = (mask << 1) | 1)
+    ;
+  do i = rand() & mask; while (i > max);
+  return (i + min);
+}
+
 static int encode_inet_addr(struct sockaddr_un *sun,
                            const struct sockaddr_in *sin,
                            int want)
@@ -244,8 +258,14 @@ static int encode_inet_addr(struct sockaddr_un *sun,
       if (unix_socket_status(sun, 0) == STALE) unlink(sun->sun_path);
     }
   } else {
+    for (i = 0; i < 10; i++) {
+      snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s:%u", sockdir,
+              inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)),
+              randrange(minautoport, maxautoport));
+      if (unix_socket_status(sun, 1) == UNUSED) goto found;
+    }
     for (desperate_p = 0; desperate_p < 2; desperate_p++) {
-      for (i = 16384; i < 65536; i++) {
+      for (i = minautoport; i <= maxautoport; i++) {
        snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s:%u", sockdir,
                 inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)),
                 (unsigned)i);
@@ -493,20 +513,15 @@ static void parse_ports(char **pp, unsigned short *min, unsigned short *max)
   int del;
 
   SKIPSPC;
-  if (*p != ':') {
-    *min = 0;
-    *max = 0xffff;
-  } else {
+  if (*p != ':')
+    { *min = 0; *max = 0xffff; }
+  else {
     p++;
-    NEXTNUMBER(q, del);
-    *min = atoi(q);
-    RESCAN(del);
+    NEXTNUMBER(q, del); *min = strtoul(q, 0, 0); RESCAN(del);
     SKIPSPC;
-    if (*p == '-') {
-      NEXTNUMBER(q, del);
-      *max = atoi(q);
-      RESCAN(del);
-    } else
+    if (*p == '-')
+      { NEXTNUMBER(q, del); *max = strtoul(q, 0, 0); RESCAN(del); }
+    else
       *max = *min;
   }
   *pp = p;
@@ -576,7 +591,7 @@ static void parse_acl_line(char **pp, aclnode ***tail)
            if (inet_pton(AF_INET, q, &addr) <= 0) goto bad;
            mask = ntohl(addr.s_addr);
          } else {
-           n = atoi(q);
+           n = strtoul(q, 0, 0);
            mask = (~0ul << (32 - n)) & 0xffffffff;
          }
          RESCAN(del);
@@ -600,13 +615,32 @@ bad:
   return;
 }
 
+static void parse_autoports(char **pp)
+{
+  char *p = *pp, *q;
+  unsigned x, y;
+  int del;
+
+  SKIPSPC;
+  NEXTNUMBER(q, del); x = strtoul(q, 0, 0); RESCAN(del);
+  SKIPSPC;
+  if (*p != '-') goto bad; p++;
+  NEXTNUMBER(q, del); y = strtoul(q, 0, 0); RESCAN(del);
+  minautoport = x; maxautoport = y;
+  return;
+
+bad:
+  D( fprintf(stderr, "bad port range (ignored)\n"); )
+  return;
+}
+
 static void parse_acl_env(const char *var, aclnode ***tail)
 {
-  char *p;
+  char *p, *q;
 
   if ((p = getenv(var)) != 0) {
-    p = xstrdup(p);
-    parse_acl_line(&p, tail);
+    p = q = xstrdup(p);
+    parse_acl_line(&q, tail);
     free(p);
   }
 }
@@ -616,16 +650,21 @@ static void readconfig(void)
   FILE *fp;
   char buf[1024];
   size_t n;
-  char *p, *cmd;
+  char *p, *q, *cmd;
 
   if ((p = getenv("NOIP_CONFIG")) == 0)
     snprintf(p = buf, sizeof(buf), "%s/.noip", home());
   D( fprintf(stderr, "noip: config file: %s\n", p); )
-  if ((fp = fopen(p, "r")) == 0)
-    goto done;
 
   parse_acl_env("NOIP_REALBIND_BEFORE", &bind_tail);
   parse_acl_env("NOIP_REALCONNECT_BEFORE", &connect_tail);
+  if ((p = getenv("NOIP_AUTOPORTS")) != 0) {
+    p = q = xstrdup(p);
+    parse_autoports(&q);
+    free(p);
+  }
+  if ((fp = fopen(p, "r")) == 0)
+    goto done;
   while (fgets(buf, sizeof(buf), fp)) {
     n = strlen(buf);
     p = buf;
@@ -643,6 +682,8 @@ static void readconfig(void)
       parse_acl_line(&p, &bind_tail);
     else if (strcmp(cmd, "realconnect") == 0)
       parse_acl_line(&p, &connect_tail);
+    else if (strcmp(cmd, "autoports") == 0)
+      parse_autoports(&p);
     else if (strcmp(cmd, "debug") == 0)
       debug = *p ? atoi(p) : 1;
     else
@@ -663,6 +704,8 @@ done:
     sockdir = xstrdup(buf);
   }
   D( fprintf(stderr, "noip: sockdir: %s\n", sockdir);
+     fprintf(stderr, "noip: autoports: %u-%u\n",
+            minautoport, maxautoport);
      fprintf(stderr, "noip: realbind acl:\n");
      dump_acl(bind_real);
      fprintf(stderr, "noip: realconnect acl:\n");