Various sorts of access control. More...

#include "asterisk.h"
#include "asterisk/network.h"
#include <ifaddrs.h>
#include "asterisk/acl.h"
#include "asterisk/channel.h"
#include "asterisk/utils.h"
#include "asterisk/lock.h"
#include "asterisk/srv.h"

Include dependency graph for acl.c:

Go to the source code of this file.

Data Structures
struct	dscp_codepoint
Functions
struct ast_ha *	ast_append_ha (const char sense, const char stuff, struct ast_ha path, int error)
	Add a new rule to a list of HAs.
int	ast_apply_ha (struct ast_ha ha, struct sockaddr_in sin)
	Apply a set of rules to a given IP address.
void	ast_copy_ha (const struct ast_ha from, struct ast_ha to)
	Copy the contents of one HA to another.
static struct ast_ha *	ast_duplicate_ha (struct ast_ha *original)
struct ast_ha *	ast_duplicate_ha_list (struct ast_ha *original)
	Duplicate the contents of a list of host access rules.
int	ast_find_ourip (struct in_addr *ourip, struct sockaddr_in bindaddr)
	Find our IP address.
void	ast_free_ha (struct ast_ha *ha)
	Free a list of HAs.
int	ast_get_ip (struct sockaddr_in sin, const char value)
	Get the IP address given a hostname.
int	ast_get_ip_or_srv (struct sockaddr_in sin, const char value, const char *service)
	Get the IP address given a hostname and optional service.
int	ast_ouraddrfor (struct in_addr them, struct in_addr us)
	Get our local IP address when contacting a remote host.
int	ast_str2cos (const char value, unsigned int cos)
	Convert a string to the appropriate COS value.
int	ast_str2tos (const char value, unsigned int tos)
	Convert a string to the appropriate TOS value.
const char *	ast_tos2str (unsigned int tos)
	Convert a TOS value into its string representation.
static int	get_local_address (struct in_addr *ourip)
static void	score_address (const struct sockaddr_in sin, struct in_addr best_addr, int *best_score)
Variables
static struct dscp_codepoint	dscp_pool1 []

Detailed Description

Various sorts of access control.

Author:: Mark Spencer <markster@digium.com>

Definition in file acl.c.

Function Documentation

struct ast_ha* ast_append_ha	(	const char *	sense,
		const char *	stuff,
		struct ast_ha *	path,
		int *	error
	)			`[read]`

Add a new rule to a list of HAs.

This adds the new host access rule to the end of the list whose head is specified by the path parameter. Rules are evaluated in a way such that if multiple rules apply to a single IP address/subnet mask, then the rule latest in the list will be used.

Parameters:

	sense	Either "permit" or "deny" (Actually any 'p' word will result in permission, and any other word will result in denial)
	stuff	The IP address and subnet mask, separated with a '/'. The subnet mask can either be in dotted-decimal format or in CIDR notation (i.e. 0-32).
	path	The head of the HA list to which we wish to append our new rule. If NULL is passed, then the new rule will become the head of the list
`[out]`	error	The integer error points to will be set non-zero if an error occurs

Returns:: The head of the HA list

Definition at line 272 of file acl.c.

References ast_debug, ast_free, ast_inet_ntoa(), ast_log(), ast_malloc, AST_SENSE_DENY, ast_strdupa, inet_aton(), LOG_WARNING, ast_ha::netaddr, ast_ha::netmask, ast_ha::next, and ast_ha::sense.

Referenced by __init_manager(), add_calltoken_ignore(), build_callno_limits(), build_device(), build_gateway(), build_peer(), build_user(), config_parse_variables(), and reload_config().

{
   struct ast_ha *ha;
   char *nm;
   struct ast_ha *prev = NULL;
   struct ast_ha *ret;
   int x;
   char *tmp = ast_strdupa(stuff);

   ret = path;
   while (path) {
      prev = path;
      path = path->next;
   }

   if (!(ha = ast_malloc(sizeof(*ha)))) {
      return ret;
   }

   if (!(nm = strchr(tmp, '/'))) {
      /* assume /32. Yes, htonl does not do anything for this particular mask
         but we better use it to show we remember about byte order */
      ha->netmask.s_addr = htonl(0xFFFFFFFF);
   } else {
      *nm = '\0';
      nm++;

      if (!strchr(nm, '.')) {
         if ((sscanf(nm, "%30d", &x) == 1) && (x >= 0) && (x <= 32)) {
            if (x == 0) {
               /* This is special-cased to prevent unpredictable
                * behavior of shifting left 32 bits
                */
               ha->netmask.s_addr = 0;
            } else {
               ha->netmask.s_addr = htonl(0xFFFFFFFF << (32 - x));
            }
         } else {
            ast_log(LOG_WARNING, "Invalid CIDR in %s\n", stuff);
            ast_free(ha);
            if (error) {
               *error = 1;
            }
            return ret;
         }
      } else if (!inet_aton(nm, &ha->netmask)) {
         ast_log(LOG_WARNING, "Invalid mask in %s\n", stuff);
         ast_free(ha);
         if (error) {
            *error = 1;
         }
         return ret;
      }
   }

   if (!inet_aton(tmp, &ha->netaddr)) {
      ast_log(LOG_WARNING, "Invalid IP address in %s\n", stuff);
      ast_free(ha);
      if (error) {
         *error = 1;
      }
      return ret;
   }

   ha->netaddr.s_addr &= ha->netmask.s_addr;

   ha->sense = strncasecmp(sense, "p", 1) ? AST_SENSE_DENY : AST_SENSE_ALLOW;

   ha->next = NULL;
   if (prev) {
      prev->next = ha;
   } else {
      ret = ha;
   }

   ast_debug(1, "%s/%s sense %d appended to acl for peer\n", ast_strdupa(ast_inet_ntoa(ha->netaddr)), ast_strdupa(ast_inet_ntoa(ha->netmask)), ha->sense);

   return ret;
}

int ast_apply_ha	(	struct ast_ha *	ha,
		struct sockaddr_in *	sin
	)

Apply a set of rules to a given IP address.

The list of host access rules is traversed, beginning with the input rule. If the IP address given matches a rule, the "sense" of that rule is used as the return value. Note that if an IP address matches multiple rules that the last one matched will be the one whose sense will be returned.

Parameters:

	ha	The head of the list of host access rules to follow
	sin	A sockaddr_in whose address is considered when matching rules

Return values:

	AST_SENSE_ALLOW	The IP address passes our ACL
	AST_SENSE_DENY	The IP address fails our ACL

Definition at line 352 of file acl.c.

References ast_copy_string(), ast_debug, ast_inet_ntoa(), ast_ha::netaddr, ast_ha::netmask, ast_ha::next, and ast_ha::sense.

Referenced by ast_sip_ouraddrfor(), authenticate(), check_access(), check_peer_ok(), parse_register_contact(), register_verify(), and skinny_register().

{
   /* Start optimistic */
   int res = AST_SENSE_ALLOW;
   while (ha) {
#if 0 /* debugging code */
      char iabuf[INET_ADDRSTRLEN];
      char iabuf2[INET_ADDRSTRLEN];
      /* DEBUG */
      ast_copy_string(iabuf, ast_inet_ntoa(sin->sin_addr), sizeof(iabuf));
      ast_copy_string(iabuf2, ast_inet_ntoa(ha->netaddr), sizeof(iabuf2));
      ast_debug(1, "##### Testing %s with %s\n", iabuf, iabuf2);
#endif
      /* For each rule, if this address and the netmask = the net address
         apply the current rule */
      if ((sin->sin_addr.s_addr & ha->netmask.s_addr) == ha->netaddr.s_addr) {
         res = ha->sense;
      }
      ha = ha->next;
   }
   return res;
}

void ast_copy_ha	(	const struct ast_ha *	from,
		struct ast_ha *	to
	)

Copy the contents of one HA to another.

This copies the internals of the 'from' HA to the 'to' HA. It is important that the 'to' HA has been allocated prior to calling this function

Parameters:

	from	Source HA to copy
	to	Destination HA to copy to

Return values:

void

Definition at line 228 of file acl.c.

References ast_ha::netaddr, ast_ha::netmask, and ast_ha::sense.

Referenced by add_calltoken_ignore(), ast_duplicate_ha(), and build_callno_limits().

{
   memcpy(&to->netaddr, &from->netaddr, sizeof(from->netaddr));
   memcpy(&to->netmask, &from->netmask, sizeof(from->netmask));
   to->sense = from->sense;
}

static struct ast_ha* ast_duplicate_ha ( struct ast_ha * original ) [static, read]

Definition at line 236 of file acl.c.

References ast_copy_ha(), and ast_malloc.

Referenced by ast_duplicate_ha_list().

{
   struct ast_ha *new_ha;

   if ((new_ha = ast_malloc(sizeof(*new_ha)))) {
      /* Copy from original to new object */
      ast_copy_ha(original, new_ha);
   }

   return new_ha;
}

struct ast_ha* ast_duplicate_ha_list ( struct ast_ha * original ) [read]

Duplicate the contents of a list of host access rules.

A deep copy of all ast_has in the list is made. The returned value is allocated on the heap and must be freed independently of the input parameter when finished.

Note:: This function is not actually used anywhere.

Parameters:

original

The ast_ha to copy

Return values:

The

head of the list of duplicated ast_has

Definition at line 250 of file acl.c.

References ast_duplicate_ha(), and ast_ha::next.

{
   struct ast_ha *start = original;
   struct ast_ha *ret = NULL;
   struct ast_ha *current, *prev = NULL;

   while (start) {
      current = ast_duplicate_ha(start);  /* Create copy of this object */
      if (prev) {
         prev->next = current;           /* Link previous to this object */
      }

      if (!ret) {
         ret = current;                  /* Save starting point */
      }

      start = start->next;                /* Go to next object */
      prev = current;                     /* Save pointer to this object */
   }
   return ret;                             /* Return start of list */
}

int ast_find_ourip	(	struct in_addr *	ourip,
		struct sockaddr_in	bindaddr
	)

Find our IP address.

This function goes through many iterations in an attempt to find our IP address. If any step along the way should fail, we move to the next item in the list. Here are the steps taken:

If bindaddr has a non-zero IP address, that is copied into ourip
We use a combination of gethostname and ast_gethostbyname to find our IP address.
We use ast_ouraddrfor with 198.41.0.4 as the destination IP address
We try some platform-specific socket operations to find the IP address

Parameters:

`[out]`	ourip	Our IP address is written here when it is found
	bindaddr	A hint used for finding our IP. See the steps above for more details

Return values:

	0	Success
	-1	Failure

Definition at line 511 of file acl.c.

References ast_debug, ast_gethostbyname(), ast_log(), ast_ouraddrfor(), get_local_address(), hp, inet_aton(), LOG_WARNING, and ourhost.

Referenced by __oh323_rtp_create(), gtalk_create_candidates(), jingle_create_candidates(), load_module(), and reload_config().

{
   char ourhost[MAXHOSTNAMELEN] = "";
   struct ast_hostent ahp;
   struct hostent *hp;
   struct in_addr saddr;

   /* just use the bind address if it is nonzero */
   if (ntohl(bindaddr.sin_addr.s_addr)) {
      memcpy(ourip, &bindaddr.sin_addr, sizeof(*ourip));
      ast_debug(3, "Attached to given IP address\n");
      return 0;
   }
   /* try to use our hostname */
   if (gethostname(ourhost, sizeof(ourhost) - 1)) {
      ast_log(LOG_WARNING, "Unable to get hostname\n");
   } else {
      if ((hp = ast_gethostbyname(ourhost, &ahp))) {
         memcpy(ourip, hp->h_addr, sizeof(*ourip));
         ast_debug(3, "Found one IP address based on local hostname %s.\n", ourhost);
         return 0;
      }
   }
   ast_debug(3, "Trying to check A.ROOT-SERVERS.NET and get our IP address for that connection\n");
   /* A.ROOT-SERVERS.NET. */
   if (inet_aton("198.41.0.4", &saddr) && !ast_ouraddrfor(&saddr, ourip)) {
      return 0;
   }
   return get_local_address(ourip);
}

void ast_free_ha ( struct ast_ha * ha )

Free a list of HAs.

Given the head of a list of HAs, it and all appended HAs are freed

Parameters:

ha

The head of the list of HAs to free

Return values:

void

Definition at line 217 of file acl.c.

References ast_free, and ast_ha::next.

Referenced by __init_manager(), add_calltoken_ignore(), build_callno_limits(), build_peer(), build_user(), destroy_gateway(), oh323_destroy_peer(), oh323_destroy_user(), peer_destructor(), reload_config(), sip_destroy_peer(), unload_module(), and user_destructor().

{
   struct ast_ha *hal;
   while (ha) {
      hal = ha;
      ha = ha->next;
      ast_free(hal);
   }
}

int ast_get_ip	(	struct sockaddr_in *	sin,
		const char *	value
	)

Get the IP address given a hostname.

Similar in nature to ast_gethostbyname, except that instead of getting an entire hostent structure, you instead are given only the IP address inserted into a sockaddr_in structure.

Parameters:

`[out]`	sin	The IP address is written into sin->sin_addr
	value	The hostname to look up

Return values:

	0	Success
	-1	Failure

Definition at line 476 of file acl.c.

References ast_get_ip_or_srv().

Referenced by build_gateway(), build_peer(), build_user(), config_parse_variables(), and peer_set_srcaddr().

{
   return ast_get_ip_or_srv(sin, value, NULL);
}

int ast_get_ip_or_srv	(	struct sockaddr_in *	sin,
		const char *	value,
		const char *	service
	)

Get the IP address given a hostname and optional service.

If the service parameter is non-NULL, then an SRV lookup will be made by prepending the service to the value parameter, separated by a '.' For example, if value is "example.com" and service is "_sip._udp" then an SRV lookup will be done for "_sip._udp.example.com". If service is NULL, then this function acts exactly like a call to ast_get_ip.

Parameters:

`[out]`	sin	The IP address is written into sin->sin_addr
	value	The hostname to look up
	service	A specific service provided by the host. A NULL service results in an A-record lookup instead of an SRV lookup

Return values:

	0	Success
	-1	Failure

Definition at line 375 of file acl.c.

References ast_get_srv(), ast_gethostbyname(), ast_log(), hp, and LOG_WARNING.

Referenced by ast_dnsmgr_lookup(), ast_get_ip(), create_addr(), dnsmgr_refresh(), and proxy_update().

{
   struct hostent *hp;
   struct ast_hostent ahp;
   char srv[256];
   char host[256];
   int tportno = ntohs(sin->sin_port);
   if (service) {
      snprintf(srv, sizeof(srv), "%s.%s", service, value);
      if (ast_get_srv(NULL, host, sizeof(host), &tportno, srv) > 0) {
         sin->sin_port = htons(tportno);
         value = host;
      }
   }
   if ((hp = ast_gethostbyname(value, &ahp))) {
      memcpy(&sin->sin_addr, hp->h_addr, sizeof(sin->sin_addr));
   } else {
      ast_log(LOG_WARNING, "Unable to lookup '%s'\n", value);
      return -1;
   }
   return 0;
}

int ast_ouraddrfor	(	struct in_addr *	them,
		struct in_addr *	us
	)

Get our local IP address when contacting a remote host.

This function will attempt to connect(2) to them over UDP using a source port of 5060. If the connect(2) call is successful, then we inspect the sockaddr_in output parameter of connect(2) to determine the IP address used to connect to them. This IP address is then copied into us.

Parameters:

	them	The IP address to which we wish to attempt to connect
`[out]`	us	The source IP address used to connect to them

Return values:

	-1	Failure
	0	Success

Definition at line 481 of file acl.c.

References ast_debug, ast_log(), LOG_ERROR, and LOG_WARNING.

Referenced by ast_find_ourip(), ast_sip_ouraddrfor(), build_gateway(), and find_subchannel_and_lock().

{
   int s;
   struct sockaddr_in sin;
   socklen_t slen;

   if ((s = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
      ast_log(LOG_ERROR, "Cannot create socket\n");
      return -1;
   }
   sin.sin_family = AF_INET;
   sin.sin_port = htons(5060);
   sin.sin_addr = *them;
   if (connect(s, (struct sockaddr *)&sin, sizeof(sin))) {
      ast_log(LOG_WARNING, "Cannot connect\n");
      close(s);
      return -1;
   }
   slen = sizeof(sin);
   if (getsockname(s, (struct sockaddr *)&sin, &slen)) {
      ast_log(LOG_WARNING, "Cannot get socket name\n");
      close(s);
      return -1;
   }
   close(s);
   ast_debug(3, "Found IP address for this socket\n");
   *us = sin.sin_addr;
   return 0;
}

int ast_str2cos	(	const char *	value,
		unsigned int *	cos
	)

Convert a string to the appropriate COS value.

Parameters:

	value	The COS string to convert
`[out]`	cos	The integer representation of that COS value

Return values:

	-1	Failure
	0	Success

Definition at line 429 of file acl.c.

Referenced by config_parse_variables(), reload_config(), and set_config().

{
   int fval;

   if (sscanf(value, "%30d", &fval) == 1) {
      if (fval < 8) {
          *cos = fval;
          return 0;
      }
   }

   return -1;
}

int ast_str2tos	(	const char *	value,
		unsigned int *	tos
	)

Convert a string to the appropriate TOS value.

Parameters:

	value	The TOS string to convert
`[out]`	tos	The integer representation of that TOS value

Return values:

	-1	Failure
	0	Success

Definition at line 443 of file acl.c.

References ARRAY_LEN, name, and dscp_codepoint::space.

Referenced by config_parse_variables(), iax_template_parse(), reload_config(), and set_config().

{
   int fval;
   unsigned int x;

   if (sscanf(value, "%30i", &fval) == 1) {
      *tos = fval & 0xFF;
      return 0;
   }

   for (x = 0; x < ARRAY_LEN(dscp_pool1); x++) {
      if (!strcasecmp(value, dscp_pool1[x].name)) {
         *tos = dscp_pool1[x].space << 2;
         return 0;
      }
   }

   return -1;
}

const char* ast_tos2str ( unsigned int tos )

Convert a TOS value into its string representation.

Parameters:

tos

The TOS value to look up

Returns:: The string equivalent of the TOS value

Definition at line 463 of file acl.c.

References ARRAY_LEN, dscp_codepoint::name, and dscp_codepoint::space.

Referenced by sip_show_settings().

{
   unsigned int x;

   for (x = 0; x < ARRAY_LEN(dscp_pool1); x++) {
      if (dscp_pool1[x].space == (tos >> 2)) {
         return dscp_pool1[x].name;
      }
   }

   return "unknown";
}

static int get_local_address ( struct in_addr * ourip ) [static]

Definition at line 115 of file acl.c.

References buf, free, malloc, and score_address().

Referenced by ast_find_ourip().

{
   int s, res = -1;
#ifdef SOLARIS
   struct lifreq *ifr = NULL;
   struct lifnum ifn;
   struct lifconf ifc;
   struct sockaddr_in *sa;
   char *buf = NULL;
   int bufsz, x;
#endif /* SOLARIS */
#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__linux__) || defined(__Darwin__)
   struct ifaddrs *ifap, *ifaphead;
   int rtnerr;
   const struct sockaddr_in *sin;
#endif /* BSD_OR_LINUX */
   struct in_addr best_addr;
   int best_score = -100;
   memset(&best_addr, 0, sizeof(best_addr));

#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__linux__) || defined(__Darwin__)
   rtnerr = getifaddrs(&ifaphead);
   if (rtnerr) {
      perror(NULL);
      return -1;
   }
#endif /* BSD_OR_LINUX */

   s = socket(AF_INET, SOCK_STREAM, 0);

   if (s > 0) {
#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__linux__) || defined(__Darwin__)
      for (ifap = ifaphead; ifap; ifap = ifap->ifa_next) {

         if (ifap->ifa_addr && ifap->ifa_addr->sa_family == AF_INET) {
            sin = (const struct sockaddr_in *) ifap->ifa_addr;
            score_address(sin, &best_addr, &best_score);
            res = 0;

            if (best_score == 0) {
               break;
            }
         }
      }
#endif /* BSD_OR_LINUX */

      /* There is no reason whatsoever that this shouldn't work on Linux or BSD also. */
#ifdef SOLARIS
      /* Get a count of interfaces on the machine */
      ifn.lifn_family = AF_INET;
      ifn.lifn_flags = 0;
      ifn.lifn_count = 0;
      if (ioctl(s, SIOCGLIFNUM, &ifn) < 0) {
         close(s);
         return -1;
      }

      bufsz = ifn.lifn_count * sizeof(struct lifreq);
      if (!(buf = malloc(bufsz))) {
         close(s);
         return -1;
      }
      memset(buf, 0, bufsz);

      /* Get a list of interfaces on the machine */
      ifc.lifc_len = bufsz;
      ifc.lifc_buf = buf;
      ifc.lifc_family = AF_INET;
      ifc.lifc_flags = 0;
      if (ioctl(s, SIOCGLIFCONF, &ifc) < 0) {
         close(s);
         free(buf);
         return -1;
      }

      for (ifr = ifc.lifc_req, x = 0; x < ifn.lifn_count; ifr++, x++) {
         sa = (struct sockaddr_in *)&(ifr->lifr_addr);
         score_address(sa, &best_addr, &best_score);
         res = 0;

         if (best_score == 0) {
            break;
         }
      }

      free(buf);
#endif /* SOLARIS */

      close(s);
   }
#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__linux__) || defined(__Darwin__)
   freeifaddrs(ifaphead);
#endif /* BSD_OR_LINUX */

   if (res == 0 && ourip) {
      memcpy(ourip, &best_addr, sizeof(*ourip));
   }
   return res;
}

static void score_address	(	const struct sockaddr_in *	sin,
		struct in_addr *	best_addr,
		int *	best_score
	)			`[static]`

Note:: Better score than a test network, but not quite as good as RFC 1918 address space. The reason is that some Linux distributions automatically configure a Zeroconf address before trying DHCP, so we want to prefer a DHCP lease to a Zeroconf address.

Definition at line 56 of file acl.c.

References ast_inet_ntoa().

Referenced by get_local_address().

{
   const char *address;
   int score;

   address = ast_inet_ntoa(sin->sin_addr);

   /* RFC 1700 alias for the local network */
   if (address[0] == '0') {
      score = -25;
   /* RFC 1700 localnet */
   } else if (strncmp(address, "127", 3) == 0) {
      score = -20;
   /* RFC 1918 non-public address space */
   } else if (strncmp(address, "10.", 3) == 0) {
      score = -5;
   /* RFC 1918 non-public address space */
   } else if (strncmp(address, "172", 3) == 0) {
      /* 172.16.0.0 - 172.19.255.255, but not 172.160.0.0 - 172.169.255.255 */
      if (address[4] == '1' && address[5] >= '6' && address[6] == '.') {
         score = -5;
      /* 172.20.0.0 - 172.29.255.255, but not 172.200.0.0 - 172.255.255.255 nor 172.2.0.0 - 172.2.255.255 */
      } else if (address[4] == '2' && address[6] == '.') {
         score = -5;
      /* 172.30.0.0 - 172.31.255.255 */
      } else if (address[4] == '3' && address[5] <= '1') {
         score = -5;
      /* All other 172 addresses are public */
      } else {
         score = 0;
      }
   /* RFC 2544 Benchmark test range (198.18.0.0 - 198.19.255.255, but not 198.180.0.0 - 198.199.255.255) */
   } else if (strncmp(address, "198.1", 5) == 0 && address[5] >= '8' && address[6] == '.') {
      score = -10;
   /* RFC 1918 non-public address space */
   } else if (strncmp(address, "192.168", 7) == 0) {
      score = -5;
   /* RFC 3330 Zeroconf network */
   } else if (strncmp(address, "169.254", 7) == 0) {
      /*!\note Better score than a test network, but not quite as good as RFC 1918
       * address space.  The reason is that some Linux distributions automatically
       * configure a Zeroconf address before trying DHCP, so we want to prefer a
       * DHCP lease to a Zeroconf address.
       */
      score = -10;
   /* RFC 3330 Test network */
   } else if (strncmp(address, "192.0.2.", 8) == 0) {
      score = -15;
   /* Every other address should be publically routable */
   } else {
      score = 0;
   }

   if (score > *best_score) {
      *best_score = score;
      memcpy(best_addr, &sin->sin_addr, sizeof(*best_addr));
   }
}

Variable Documentation

struct dscp_codepoint dscp_pool1[] [static]

Definition at line 405 of file acl.c.

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acl.c File Reference

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Detailed Description

Function Documentation

Variable Documentation