import of dnsmasq-2.0.tar.gz

src/util.c

@@ -0,0 +1,217 @@
+/* dnsmasq is Copyright (c) 2000 Simon Kelley
+
+   This program 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; version 2 dated June, 1991.
+
+   This program 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.
+*/
+
+
+/* Code in this file contributed by Rob Funk. */
+
+#include "dnsmasq.h"
+
+/* Prefer arc4random(3) over random(3) over rand(3) */
+/* Also prefer /dev/urandom over /dev/random, to preserve the entropy pool */
+#ifdef HAVE_ARC4RANDOM
+# define rand()		arc4random()
+# define srand(s)	(void)0
+# define RANDFILE	(NULL)
+#else
+# ifdef HAVE_RANDOM
+#  define rand()	random()
+#  define srand(s)	srandom(s)
+# endif
+# ifdef HAVE_DEV_URANDOM
+#  define RANDFILE	"/dev/urandom"
+# else
+#  ifdef HAVE_DEV_RANDOM
+#   define RANDFILE	"/dev/random"
+#  else
+#   define RANDFILE	(NULL)
+#  endif
+# endif
+#endif
+
+unsigned short rand16(void)
+{
+  static int been_seeded = 0;
+  const char *randfile = RANDFILE;
+  
+  if (! been_seeded) 
+    {
+      int fd, n = 0;
+      unsigned int c = 0, seed = 0, badseed;
+      char sbuf[sizeof(seed)];
+      char *s;
+      struct timeval now;
+
+      /* get the bad seed as a backup */
+      /* (but we'd rather have something more random) */
+      gettimeofday(&now, NULL);
+      badseed = now.tv_sec ^ now.tv_usec ^ (getpid() << 16);
+      
+      fd = open(randfile, O_RDONLY);
+      if (fd < 0) 
+	seed = badseed;
+      else
+	{
+	  s = (char *) &seed;
+	  while ( (c < sizeof(seed)) &&
+		  ((n = read(fd, sbuf, sizeof(seed)) > 0)) ) 
+	    {
+	      memcpy(s, sbuf, n);
+	      s += n;
+	      c += n;
+	    }
+	  if (n < 0)
+	    {
+	      seed = badseed;
+	    }
+	  close(fd);
+	}
+
+      srand(seed);
+      been_seeded = 1;
+    }
+  
+  /* Some rand() implementations have less randomness in low bits
+   * than in high bits, so we only pay attention to the high ones.
+   * But most implementations don't touch the high bit, so we 
+   * ignore that one.
+   */
+  return( (unsigned short) (rand() >> 15) );
+}
+
+int legal_char(char c)
+{
+  /* check for legal char a-z A-Z 0-9 - 
+     (also / , used for RFC2317 and _ used in windows queries) */
+  if ((c >= 'A' && c <= 'Z') ||
+      (c >= 'a' && c <= 'z') ||
+      (c >= '0' && c <= '9') ||
+      c == '-' || c == '/' || c == '_')
+    return 1;
+  
+  return 0;
+}
+  
+int canonicalise(char *s)
+{
+  /* check for legal chars ans remove trailing . */
+  int l = strlen(s);
+  char c;
+
+  if (l>0 && s[l-1] == '.')
+    s[l-1] = 0;
+
+  while ((c = *s++))
+    if (c != '.' && !legal_char(c))
+      return 0;
+  
+  return 1;
+}
+
+/* for use during startup */
+void *safe_malloc(int size)
+{
+  void *ret = malloc(size);
+  
+  if (!ret)
+    die("could not get memory", NULL);
+     
+  return ret;
+}
+    
+char *safe_string_alloc(char *cp)
+{
+  char *ret = NULL;
+
+  if (cp && strlen(cp) != 0)
+    {
+      ret = safe_malloc(strlen(cp)+1);
+      strcpy(ret, cp);
+    }
+
+  return ret;
+}
+
+void complain(char *message, char *arg1)
+{
+  char *errmess = strerror(errno);
+  
+  if (!arg1)
+    arg1 = errmess;
+  
+  fprintf(stderr, "dnsmasq: ");
+  fprintf(stderr, message, arg1, errmess);
+  fprintf(stderr, "\n");
+  
+  syslog(LOG_CRIT, message, arg1, errmess);
+}
+
+void die(char *message, char *arg1)
+{
+  complain(message, arg1);
+  syslog(LOG_CRIT, "FAILED to start up");
+  exit(1);
+}
+
+int sockaddr_isequal(union mysockaddr *s1, union mysockaddr *s2)
+{
+  if (s1->sa.sa_family == s2->sa.sa_family)
+    { 
+      if (s1->sa.sa_family == AF_INET &&
+	  s1->in.sin_port == s2->in.sin_port &&
+	  memcmp(&s1->in.sin_addr, &s2->in.sin_addr, sizeof(struct in_addr)) == 0)
+	return 1;
+#ifdef HAVE_IPV6      
+      if (s1->sa.sa_family == AF_INET6 &&
+	  s1->in6.sin6_port == s2->in6.sin6_port &&
+	  s1->in6.sin6_flowinfo == s2->in6.sin6_flowinfo &&
+	  memcmp(&s1->in6.sin6_addr, &s2->in6.sin6_addr, sizeof(struct in6_addr)) == 0)
+	return 1;
+#endif
+    }
+  return 0;
+}
+
+int sa_len(union mysockaddr *addr)
+{
+#ifdef HAVE_SOCKADDR_SA_LEN
+  return addr->sa.sa_len;
+#else
+#ifdef HAVE_IPV6
+  if (addr->sa.sa_family == AF_INET6)
+    return sizeof(addr->in6);
+  else
+#endif
+    return sizeof(addr->in); 
+#endif
+}
+
+/* don't use strcasecmp and friends here - they may be messed up by LOCALE */
+int hostname_isequal(unsigned char *a, unsigned char *b)
+{
+  unsigned int c1, c2;
+  
+  do {
+    c1 = *a++;
+    c2 = *b++;
+    
+    if (c1 >= 'A' && c1 <= 'Z')
+      c1 += 'a' - 'A';
+    if (c2 >= 'A' && c2 <= 'Z')
+      c2 += 'a' - 'A';
+    
+    if (c1 != c2)
+      return 0;
+  } while (c1);
+  
+  return 1;
+}
+