- Faster Call-ID generator

- Increments directly the HEX representation of the random number

modules/tm/callid.c

@@ -0,0 +1,157 @@
+/*
+ * $Id$
+ *
+ * Fast Call-ID Generator
+ *
+ * Copyright (C) 2001-2003 Fhg Fokus
+ *
+ * This file is part of ser, a free SIP server.
+ *
+ * ser 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
+ *
+ * For a license to use the ser software under conditions
+ * other than those described here, or to purchase support for this
+ * software, please contact iptel.org by e-mail at the following addresses:
+ *    [email protected]
+ *
+ * ser 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 this program; if not, write to the Free Software 
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * History:
+ * ----------
+ * 2003-04-09 Created by janakj
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "../../dprint.h"
+#include "../../pt.h"
+#include "callid.h"
+
+#define CALLID_NR_LEN 20
+
+/* Call-ID has the following form: <callid_nr>-<pid>@<ip>
+ * callid_nr is initialized as a random number and continually
+ * increases; -<pid>@<ip> is kept in callid_suffix
+ */
+#define CALLID_SUFFIX_LEN ( 1 /* - */                                            + \
+			    5 /* pid */                                          + \
+                           42 /* embedded v4inv6 address can be looong '128.' */ + \
+	                    2 /* parenthessis [] */                              + \
+                            1 /* ZT 0 */                                         + \
+	                   16 /* one never knows ;-) */                            \
+                          )
+
+#define CID_SEP '-' /* the character which separates random from constant part */
+
+static unsigned long callid_nr;
+static char callid_buf[CALLID_NR_LEN + CALLID_SUFFIX_LEN];
+
+str callid_prefix;
+str callid_suffix;
+
+
+/*
+ * Initialize the Call-ID generator -- generates random prefix
+ */
+int init_callid(void)
+{
+	int rand_bits, i;
+
+	     /* calculate the initial call-id */
+	     /* how many bits and chars do we need to display the 
+	      * whole ULONG number */
+	callid_prefix.len = sizeof(unsigned long) * 2;
+	callid_prefix.s = callid_buf;
+
+	if (callid_prefix.len > CALLID_NR_LEN) {
+		LOG(L_ERR, "ERROR: Too small callid buffer\n");
+		return -1;
+	}
+	
+	for(rand_bits = 0, i = RAND_MAX; i; i >>= 1, rand_bits++);  /* how long are the rand()s ? */
+	i = callid_prefix.len * 4 / rand_bits; /* how many rands() fit in the ULONG ? */
+
+	     /* now fill in the callid with as many random
+	      * numbers as you can + 1 */
+	callid_nr = rand(); /* this is the + 1 */
+	while(i--) {
+		callid_nr <<= rand_bits;
+		callid_nr |= rand();
+	}
+
+	i = snprintf(callid_prefix.s, callid_prefix.len, "%0*lx", callid_prefix.len, callid_nr);
+	if ((i == -1) || (i > callid_prefix.len)) {
+		LOG(L_CRIT, "BUG: SORRY, callid calculation failed\n");
+		return -2;
+	}
+	
+	DBG("Call-ID initialization: '%.*s'\n", callid_prefix.len, callid_prefix.s);
+	return 0;
+}
+
+
+/*
+ * Child initialization -- generates suffix
+ */
+int child_init_callid(int rank) 
+{
+	callid_suffix.s = callid_buf + callid_prefix.len;
+
+	callid_suffix.len = snprintf(callid_suffix.s, CALLID_SUFFIX_LEN,
+				     "%c%d@%.*s", CID_SEP, my_pid(), 
+				     sock_info[bind_idx].address_str.len,
+				     sock_info[bind_idx].address_str.s);
+	if ((callid_suffix.len == -1) || (callid_suffix.len > CALLID_SUFFIX_LEN)) {
+		LOG(L_ERR, "ERROR: child_init_callid: buffer too small\n");
+		return -1;
+	}
+
+	DBG("DEBUG: callid: '%.*s'\n", callid_prefix.len + callid_suffix.len, callid_prefix.s);
+	return 0;
+}
+
+
+/*
+ * Increment a character in hex, return
+ * carry flag
+ */
+static inline int inc_hexchar(char* _c)
+{
+	if (*_c == '9') {
+		*_c = 'a';
+		return 0;
+	}
+
+	if (*_c == 'f') {
+		*_c = '0';
+		return 1;
+	}
+
+	(*_c)++;
+	return 0;
+}
+
+
+/*
+ * Get a unique Call-ID
+ */
+void generate_callid(str* callid)
+{
+	int i;
+
+	for(i = callid_prefix.len; i; i--) {
+		if (!inc_hexchar(callid_prefix.s + i - 1)) break;
+	}
+	callid->s = callid_prefix.s;
+	callid->len = callid_prefix.len + callid_suffix.len;
+}

modules/tm/callid.h

@@ -0,0 +1,58 @@
+/*
+ * $Id$
+ *
+ * Fast Call-ID Generator
+ *
+ * Copyright (C) 2001-2003 Fhg Fokus
+ *
+ * This file is part of ser, a free SIP server.
+ *
+ * ser 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
+ *
+ * For a license to use the ser software under conditions
+ * other than those described here, or to purchase support for this
+ * software, please contact iptel.org by e-mail at the following addresses:
+ *    [email protected]
+ *
+ * ser 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 this program; if not, write to the Free Software 
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * History:
+ * ----------
+ * 2003-04-09 Created by janakj
+ */
+
+#ifndef CALLID_H
+#define CALLID_H
+
+#include "../../str.h"
+
+
+/*
+ * Initialize the Call-ID generator -- generates random prefix
+ */
+int init_callid(void);
+
+
+/*
+ * Child initialization -- generates suffix
+ */
+int child_init_callid(int rank);
+
+
+/*
+ * Get a unique Call-ID
+ */
+void generate_callid(str* callid);
+
+
+#endif /* CALLID_H */