config.c - platform/external/android-clat - Git at Google

 /*
  * Copyright 2011 Daniel Drown
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  * config.c - configuration settings
  */

 #include <string.h>
 #include <stdlib.h>
 #include <arpa/inet.h>
 #include <stdio.h>
 #include <limits.h>
 #include <errno.h>
 #include <unistd.h>

 #include <cutils/config_utils.h>

 #include "config.h"
 #include "dns64.h"
 #include "logging.h"
 #include "getaddr.h"
 #include "clatd.h"
 #include "setroute.h"

 struct clat_config Global_Clatd_Config;

 /* function: config_item_str
  * locates the config item and returns the pointer to a string, or NULL on failure.  Caller frees pointer
  * root       - parsed configuration
  * item_name  - name of config item to locate
  * defaultvar - value to use if config item isn't present
  */
 char *config_item_str(cnode *root, const char *item_name, const char *defaultvar) {
   const char *tmp;

   if(!(tmp = config_str(root, item_name, defaultvar))) {
     logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name);
     return NULL;
   }
   return strdup(tmp);
 }

 /* function: config_item_int16_t
  * locates the config item, parses the integer, and returns the pointer ret_val_ptr, or NULL on failure
  * root        - parsed configuration
  * item_name   - name of config item to locate
  * defaultvar  - value to use if config item isn't present
  * ret_val_ptr - pointer for return value storage
  */
 int16_t *config_item_int16_t(cnode *root, const char *item_name, const char *defaultvar, int16_t *ret_val_ptr) {
   const char *tmp;
   char *endptr;
   long int conf_int;

   if(!(tmp = config_str(root, item_name, defaultvar))) {
     logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name);
     return NULL;
   }

   errno = 0;
   conf_int = strtol(tmp,&endptr,10);
   if(errno > 0) {
     logmsg(ANDROID_LOG_FATAL,"%s config item is not numeric: %s (error=%s)",item_name,tmp,strerror(errno));
     return NULL;
   }
   if(endptr == tmp || *tmp == '\0') {
     logmsg(ANDROID_LOG_FATAL,"%s config item is not numeric: %s",item_name,tmp);
     return NULL;
   }
   if(*endptr != '\0') {
     logmsg(ANDROID_LOG_FATAL,"%s config item contains non-numeric characters: %s",item_name,endptr);
     return NULL;
   }
   if(conf_int > INT16_MAX || conf_int < INT16_MIN) {
     logmsg(ANDROID_LOG_FATAL,"%s config item is too big/small: %d",item_name,conf_int);
     return NULL;
   }
   *ret_val_ptr = conf_int;
   return ret_val_ptr;
 }

 /* function: config_item_ip
  * locates the config item, parses the ipv4 address, and returns the pointer ret_val_ptr, or NULL on failure
  * root        - parsed configuration
  * item_name   - name of config item to locate
  * defaultvar  - value to use if config item isn't present
  * ret_val_ptr - pointer for return value storage
  */
 struct in_addr *config_item_ip(cnode *root, const char *item_name, const char *defaultvar, struct in_addr *ret_val_ptr) {
   const char *tmp;
   int status;

   if(!(tmp = config_str(root, item_name, defaultvar))) {
     logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name);
     return NULL;
   }

   status = inet_pton(AF_INET, tmp, ret_val_ptr);
   if(status <= 0) {
     logmsg(ANDROID_LOG_FATAL,"invalid IPv4 address specified for %s: %s", item_name, tmp);
     return NULL;
   }

   return ret_val_ptr;
 }

 /* function: config_item_ip6
  * locates the config item, parses the ipv6 address, and returns the pointer ret_val_ptr, or NULL on failure
  * root        - parsed configuration
  * item_name   - name of config item to locate
  * defaultvar  - value to use if config item isn't present
  * ret_val_ptr - pointer for return value storage
  */
 struct in6_addr *config_item_ip6(cnode *root, const char *item_name, const char *defaultvar, struct in6_addr *ret_val_ptr) {
   const char *tmp;
   int status;

   if(!(tmp = config_str(root, item_name, defaultvar))) {
     logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name);
     return NULL;
   }

   status = inet_pton(AF_INET6, tmp, ret_val_ptr);
   if(status <= 0) {
     logmsg(ANDROID_LOG_FATAL,"invalid IPv6 address specified for %s: %s", item_name, tmp);
     return NULL;
   }

   return ret_val_ptr;
 }

 /* function: free_config
  * frees the memory used by the global config variable
  */
 void free_config() {
   if(Global_Clatd_Config.plat_from_dns64_hostname) {
     free(Global_Clatd_Config.plat_from_dns64_hostname);
     Global_Clatd_Config.plat_from_dns64_hostname = NULL;
   }
 }

 /* function: dns64_detection
  * does dns lookups to set the plat subnet or exits on failure, waits forever for a dns response with a query backoff timer
  */
 void dns64_detection() {
   int backoff_sleep, status;
   struct in6_addr tmp_ptr;

   backoff_sleep = 1;

   while(1) {
     status = plat_prefix(Global_Clatd_Config.plat_from_dns64_hostname,&tmp_ptr);
     if(status > 0) {
       memcpy(&Global_Clatd_Config.plat_subnet, &tmp_ptr, sizeof(struct in6_addr));
       return;
     }
     if(status < 0) {
       logmsg(ANDROID_LOG_FATAL, "dns64_detection/no dns64, giving up\n");
       exit(1);
     }
     logmsg(ANDROID_LOG_WARN, "dns64_detection failed, sleeping for %d seconds", backoff_sleep);
     sleep(backoff_sleep);
     if(backoff_sleep >= 120) {
       backoff_sleep = 120;
     } else {
       backoff_sleep *= 2;
     }
   }
 }


 /* function: config_generate_local_ipv6_subnet
  * generates the local ipv6 subnet when given the interface ip
  * requires config.ipv6_host_id
  * interface_ip - in: interface ip, out: local ipv6 host address
  */
 void config_generate_local_ipv6_subnet(struct in6_addr *interface_ip) {
   int i;

   for(i = 2; i < 4; i++) {
     interface_ip->s6_addr32[i] = Global_Clatd_Config.ipv6_host_id.s6_addr32[i];
   }
 }

 /* function: subnet_from_interface
  * finds the ipv6 subnet configured on the specified interface
  * root      - parsed configuration
  * interface - network interface name
  */
 int subnet_from_interface(cnode *root, const char *interface) {
   union anyip *interface_ip;

   if(!config_item_ip6(root, "ipv6_host_id", "::200:5E10:0:0", &Global_Clatd_Config.ipv6_host_id))
     return 0;

   interface_ip = getinterface_ip(interface, AF_INET6);
   if(!interface_ip) {
     logmsg(ANDROID_LOG_FATAL,"unable to find an ipv6 ip on interface %s",interface);
     return 0;
   }

   memcpy(&Global_Clatd_Config.ipv6_local_subnet, &interface_ip->ip6, sizeof(struct in6_addr));
   free(interface_ip);

   config_generate_local_ipv6_subnet(&Global_Clatd_Config.ipv6_local_subnet);

   return 1;
 }

 /* function: read_config
  * reads the config file and parses it into the global variable Global_Clatd_Config. returns 0 on failure, 1 on success
  * file             - filename to parse
  * uplink_interface - interface to use to reach the internet and supplier of address space
  * plat_prefix      - (optional) plat prefix to use, otherwise follow config file
  */
 int read_config(const char *file, const char *uplink_interface, const char *plat_prefix) {
   cnode *root = config_node("", "");
   void *tmp_ptr = NULL;

   if(!root) {
     logmsg(ANDROID_LOG_FATAL,"out of memory");
     return 0;
   }

   memset(&Global_Clatd_Config, '\0', sizeof(Global_Clatd_Config));

   config_load_file(root, file);
   if(root->first_child == NULL) {
     logmsg(ANDROID_LOG_FATAL,"Could not read config file %s", file);
     goto failed;
   }

   strncpy(Global_Clatd_Config.default_pdp_interface, uplink_interface, sizeof(Global_Clatd_Config.default_pdp_interface));

   if(!subnet_from_interface(root,Global_Clatd_Config.default_pdp_interface))
     goto failed;

   if(!config_item_int16_t(root, "mtu", "-1", &Global_Clatd_Config.mtu))
     goto failed;

   if(!config_item_int16_t(root, "ipv4mtu", "-1", &Global_Clatd_Config.ipv4mtu))
     goto failed;

   if(!config_item_ip(root, "ipv4_local_subnet", DEFAULT_IPV4_LOCAL_SUBNET, &Global_Clatd_Config.ipv4_local_subnet))
     goto failed;

   if(!config_item_ip6(root, "ipv6_local_address", DEFAULT_IPV6_LOCAL_ADDRESS, &Global_Clatd_Config.ipv6_local_address))
     goto failed;

   if(plat_prefix) { // plat subnet is coming from the command line
     if(inet_pton(AF_INET6, plat_prefix, &Global_Clatd_Config.plat_subnet) <= 0) {
       logmsg(ANDROID_LOG_FATAL,"invalid IPv6 address specified for plat prefix: %s", plat_prefix);
       goto failed;
     }
   } else {
     tmp_ptr = (void *)config_item_str(root, "plat_from_dns64", "yes");
     if(!tmp_ptr || strcmp(tmp_ptr, "no") == 0) {
       free(tmp_ptr);

       if(!config_item_ip6(root, "plat_subnet", NULL, &Global_Clatd_Config.plat_subnet)) {
         logmsg(ANDROID_LOG_FATAL, "plat_from_dns64 disabled, but no plat_subnet specified");
         goto failed;
       }
     } else {
       free(tmp_ptr);

       if(!(Global_Clatd_Config.plat_from_dns64_hostname = config_item_str(root, "plat_from_dns64_hostname", DEFAULT_DNS64_DETECTION_HOSTNAME)))
         goto failed;
       dns64_detection();
     }
   }


   return 1;

 failed:
   free(root);
   free_config();
   return 0;
 }

 /* function; dump_config
  * prints the current config
  */
 void dump_config() {
   char charbuffer[INET6_ADDRSTRLEN];

   logmsg(ANDROID_LOG_DEBUG,"mtu = %d",Global_Clatd_Config.mtu);
   logmsg(ANDROID_LOG_DEBUG,"ipv4mtu = %d",Global_Clatd_Config.ipv4mtu);
   logmsg(ANDROID_LOG_DEBUG,"ipv6_local_address = %s",inet_ntop(AF_INET6, &Global_Clatd_Config.ipv6_local_address, charbuffer, sizeof(charbuffer)));
   logmsg(ANDROID_LOG_DEBUG,"ipv6_local_subnet = %s",inet_ntop(AF_INET6, &Global_Clatd_Config.ipv6_local_subnet, charbuffer, sizeof(charbuffer)));
   logmsg(ANDROID_LOG_DEBUG,"ipv4_local_subnet = %s",inet_ntop(AF_INET, &Global_Clatd_Config.ipv4_local_subnet, charbuffer, sizeof(charbuffer)));
   logmsg(ANDROID_LOG_DEBUG,"plat_subnet = %s",inet_ntop(AF_INET6, &Global_Clatd_Config.plat_subnet, charbuffer, sizeof(charbuffer)));
   logmsg(ANDROID_LOG_DEBUG,"default_pdp_interface = %s",Global_Clatd_Config.default_pdp_interface);
 }
	/*
	* Copyright 2011 Daniel Drown
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*
	* config.c - configuration settings
	*/

	#include <string.h>
	#include <stdlib.h>
	#include <arpa/inet.h>
	#include <stdio.h>
	#include <limits.h>
	#include <errno.h>
	#include <unistd.h>

	#include <cutils/config_utils.h>

	#include "config.h"
	#include "dns64.h"
	#include "logging.h"
	#include "getaddr.h"
	#include "clatd.h"
	#include "setroute.h"

	struct clat_config Global_Clatd_Config;

	/* function: config_item_str
	* locates the config item and returns the pointer to a string, or NULL on failure. Caller frees pointer
	* root - parsed configuration
	* item_name - name of config item to locate
	* defaultvar - value to use if config item isn't present
	*/
	char config_item_str(cnode root, const char item_name, const char defaultvar) {
	const char *tmp;

	if(!(tmp = config_str(root, item_name, defaultvar))) {
	logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name);
	return NULL;
	}
	return strdup(tmp);
	}

	/* function: config_item_int16_t
	* locates the config item, parses the integer, and returns the pointer ret_val_ptr, or NULL on failure
	* root - parsed configuration
	* item_name - name of config item to locate
	* defaultvar - value to use if config item isn't present
	* ret_val_ptr - pointer for return value storage
	*/
	int16_t config_item_int16_t(cnode root, const char item_name, const char defaultvar, int16_t *ret_val_ptr) {
	const char *tmp;
	char *endptr;
	long int conf_int;

	if(!(tmp = config_str(root, item_name, defaultvar))) {
	logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name);
	return NULL;
	}

	errno = 0;
	conf_int = strtol(tmp,&endptr,10);
	if(errno > 0) {
	logmsg(ANDROID_LOG_FATAL,"%s config item is not numeric: %s (error=%s)",item_name,tmp,strerror(errno));
	return NULL;
	}
	if(endptr == tmp \|\| *tmp == '\0') {
	logmsg(ANDROID_LOG_FATAL,"%s config item is not numeric: %s",item_name,tmp);
	return NULL;
	}
	if(*endptr != '\0') {
	logmsg(ANDROID_LOG_FATAL,"%s config item contains non-numeric characters: %s",item_name,endptr);
	return NULL;
	}
	if(conf_int > INT16_MAX \|\| conf_int < INT16_MIN) {
	logmsg(ANDROID_LOG_FATAL,"%s config item is too big/small: %d",item_name,conf_int);
	return NULL;
	}
	*ret_val_ptr = conf_int;
	return ret_val_ptr;
	}

	/* function: config_item_ip
	* locates the config item, parses the ipv4 address, and returns the pointer ret_val_ptr, or NULL on failure
	* root - parsed configuration
	* item_name - name of config item to locate
	* defaultvar - value to use if config item isn't present
	* ret_val_ptr - pointer for return value storage
	*/
	struct in_addr config_item_ip(cnode root, const char item_name, const char defaultvar, struct in_addr *ret_val_ptr) {
	const char *tmp;
	int status;

	if(!(tmp = config_str(root, item_name, defaultvar))) {
	logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name);
	return NULL;
	}

	status = inet_pton(AF_INET, tmp, ret_val_ptr);
	if(status <= 0) {
	logmsg(ANDROID_LOG_FATAL,"invalid IPv4 address specified for %s: %s", item_name, tmp);
	return NULL;
	}

	return ret_val_ptr;
	}

	/* function: config_item_ip6
	* locates the config item, parses the ipv6 address, and returns the pointer ret_val_ptr, or NULL on failure
	* root - parsed configuration
	* item_name - name of config item to locate
	* defaultvar - value to use if config item isn't present
	* ret_val_ptr - pointer for return value storage
	*/
	struct in6_addr config_item_ip6(cnode root, const char item_name, const char defaultvar, struct in6_addr *ret_val_ptr) {
	const char *tmp;
	int status;

	if(!(tmp = config_str(root, item_name, defaultvar))) {
	logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name);
	return NULL;
	}

	status = inet_pton(AF_INET6, tmp, ret_val_ptr);
	if(status <= 0) {
	logmsg(ANDROID_LOG_FATAL,"invalid IPv6 address specified for %s: %s", item_name, tmp);
	return NULL;
	}

	return ret_val_ptr;
	}

	/* function: free_config
	* frees the memory used by the global config variable
	*/
	void free_config() {
	if(Global_Clatd_Config.plat_from_dns64_hostname) {
	free(Global_Clatd_Config.plat_from_dns64_hostname);
	Global_Clatd_Config.plat_from_dns64_hostname = NULL;
	}
	}

	/* function: dns64_detection
	* does dns lookups to set the plat subnet or exits on failure, waits forever for a dns response with a query backoff timer
	*/
	void dns64_detection() {
	int backoff_sleep, status;
	struct in6_addr tmp_ptr;

	backoff_sleep = 1;

	while(1) {
	status = plat_prefix(Global_Clatd_Config.plat_from_dns64_hostname,&tmp_ptr);
	if(status > 0) {
	memcpy(&Global_Clatd_Config.plat_subnet, &tmp_ptr, sizeof(struct in6_addr));
	return;
	}
	if(status < 0) {
	logmsg(ANDROID_LOG_FATAL, "dns64_detection/no dns64, giving up\n");
	exit(1);
	}
	logmsg(ANDROID_LOG_WARN, "dns64_detection failed, sleeping for %d seconds", backoff_sleep);
	sleep(backoff_sleep);
	if(backoff_sleep >= 120) {
	backoff_sleep = 120;
	} else {
	backoff_sleep *= 2;
	}
	}
	}


	/* function: config_generate_local_ipv6_subnet
	* generates the local ipv6 subnet when given the interface ip
	* requires config.ipv6_host_id
	* interface_ip - in: interface ip, out: local ipv6 host address
	*/
	void config_generate_local_ipv6_subnet(struct in6_addr *interface_ip) {
	int i;

	for(i = 2; i < 4; i++) {
	interface_ip->s6_addr32[i] = Global_Clatd_Config.ipv6_host_id.s6_addr32[i];
	}
	}

	/* function: subnet_from_interface
	* finds the ipv6 subnet configured on the specified interface
	* root - parsed configuration
	* interface - network interface name
	*/
	int subnet_from_interface(cnode root, const char interface) {
	union anyip *interface_ip;

	if(!config_item_ip6(root, "ipv6_host_id", "::200:5E10:0:0", &Global_Clatd_Config.ipv6_host_id))
	return 0;

	interface_ip = getinterface_ip(interface, AF_INET6);
	if(!interface_ip) {
	logmsg(ANDROID_LOG_FATAL,"unable to find an ipv6 ip on interface %s",interface);
	return 0;
	}

	memcpy(&Global_Clatd_Config.ipv6_local_subnet, &interface_ip->ip6, sizeof(struct in6_addr));
	free(interface_ip);

	config_generate_local_ipv6_subnet(&Global_Clatd_Config.ipv6_local_subnet);

	return 1;
	}

	/* function: read_config
	* reads the config file and parses it into the global variable Global_Clatd_Config. returns 0 on failure, 1 on success
	* file - filename to parse
	* uplink_interface - interface to use to reach the internet and supplier of address space
	* plat_prefix - (optional) plat prefix to use, otherwise follow config file
	*/
	int read_config(const char file, const char uplink_interface, const char *plat_prefix) {
	cnode *root = config_node("", "");
	void *tmp_ptr = NULL;

	if(!root) {
	logmsg(ANDROID_LOG_FATAL,"out of memory");
	return 0;
	}

	memset(&Global_Clatd_Config, '\0', sizeof(Global_Clatd_Config));

	config_load_file(root, file);
	if(root->first_child == NULL) {
	logmsg(ANDROID_LOG_FATAL,"Could not read config file %s", file);
	goto failed;
	}

	strncpy(Global_Clatd_Config.default_pdp_interface, uplink_interface, sizeof(Global_Clatd_Config.default_pdp_interface));

	if(!subnet_from_interface(root,Global_Clatd_Config.default_pdp_interface))
	goto failed;

	if(!config_item_int16_t(root, "mtu", "-1", &Global_Clatd_Config.mtu))
	goto failed;

	if(!config_item_int16_t(root, "ipv4mtu", "-1", &Global_Clatd_Config.ipv4mtu))
	goto failed;

	if(!config_item_ip(root, "ipv4_local_subnet", DEFAULT_IPV4_LOCAL_SUBNET, &Global_Clatd_Config.ipv4_local_subnet))
	goto failed;

	if(!config_item_ip6(root, "ipv6_local_address", DEFAULT_IPV6_LOCAL_ADDRESS, &Global_Clatd_Config.ipv6_local_address))
	goto failed;

	if(plat_prefix) { // plat subnet is coming from the command line
	if(inet_pton(AF_INET6, plat_prefix, &Global_Clatd_Config.plat_subnet) <= 0) {
	logmsg(ANDROID_LOG_FATAL,"invalid IPv6 address specified for plat prefix: %s", plat_prefix);
	goto failed;
	}
	} else {
	tmp_ptr = (void *)config_item_str(root, "plat_from_dns64", "yes");
	if(!tmp_ptr \|\| strcmp(tmp_ptr, "no") == 0) {
	free(tmp_ptr);

	if(!config_item_ip6(root, "plat_subnet", NULL, &Global_Clatd_Config.plat_subnet)) {
	logmsg(ANDROID_LOG_FATAL, "plat_from_dns64 disabled, but no plat_subnet specified");
	goto failed;
	}
	} else {
	free(tmp_ptr);

	if(!(Global_Clatd_Config.plat_from_dns64_hostname = config_item_str(root, "plat_from_dns64_hostname", DEFAULT_DNS64_DETECTION_HOSTNAME)))
	goto failed;
	dns64_detection();
	}
	}


	return 1;

	failed:
	free(root);
	free_config();
	return 0;
	}

	/* function; dump_config
	* prints the current config
	*/
	void dump_config() {
	char charbuffer[INET6_ADDRSTRLEN];

	logmsg(ANDROID_LOG_DEBUG,"mtu = %d",Global_Clatd_Config.mtu);
	logmsg(ANDROID_LOG_DEBUG,"ipv4mtu = %d",Global_Clatd_Config.ipv4mtu);
	logmsg(ANDROID_LOG_DEBUG,"ipv6_local_address = %s",inet_ntop(AF_INET6, &Global_Clatd_Config.ipv6_local_address, charbuffer, sizeof(charbuffer)));
	logmsg(ANDROID_LOG_DEBUG,"ipv6_local_subnet = %s",inet_ntop(AF_INET6, &Global_Clatd_Config.ipv6_local_subnet, charbuffer, sizeof(charbuffer)));
	logmsg(ANDROID_LOG_DEBUG,"ipv4_local_subnet = %s",inet_ntop(AF_INET, &Global_Clatd_Config.ipv4_local_subnet, charbuffer, sizeof(charbuffer)));
	logmsg(ANDROID_LOG_DEBUG,"plat_subnet = %s",inet_ntop(AF_INET6, &Global_Clatd_Config.plat_subnet, charbuffer, sizeof(charbuffer)));
	logmsg(ANDROID_LOG_DEBUG,"default_pdp_interface = %s",Global_Clatd_Config.default_pdp_interface);
	}