#include "asterisk.h"
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include "asterisk/channel.h"
#include "asterisk/srv.h"
#include "asterisk/dns.h"
#include "asterisk/utils.h"
#include "asterisk/linkedlists.h"
Go to the source code of this file.
Data Structures | |
struct | srv_context |
struct | srv_context::srv_entries |
struct | srv_entry |
Functions | |
int | ast_get_srv (struct ast_channel *chan, char *host, int hostlen, int *port, const char *service) |
void | ast_srv_cleanup (struct srv_context **context) |
Cleanup resources associated with ast_srv_lookup. | |
int | ast_srv_get_nth_record (struct srv_context *context, int record_num, const char **host, unsigned short *port, unsigned short *priority, unsigned short *weight) |
Retrieve details from a specific SRV record. | |
unsigned int | ast_srv_get_record_count (struct srv_context *context) |
Get the number of records for a given SRV context. | |
int | ast_srv_lookup (struct srv_context **context, const char *service, const char **host, unsigned short *port) |
Retrieve set of SRV lookups, in order. | |
static int | parse_srv (unsigned char *answer, int len, unsigned char *msg, struct srv_entry **result) |
static void | process_weights (struct srv_context *context) |
static int | srv_callback (void *context, unsigned char *answer, int len, unsigned char *fullanswer) |
Definition in file srv.c.
int ast_get_srv | ( | struct ast_channel * | chan, | |
char * | host, | |||
int | hostlen, | |||
int * | port, | |||
const char * | service | |||
) |
chan | Ast channel | |
host | host name (return value) | |
hostlen | Length of string "host" | |
port | Port number (return value) | |
service | Service tag for SRV lookup (like "_sip._udp" or "_stun._udp" |
Definition at line 259 of file srv.c.
References ast_autoservice_start(), ast_autoservice_stop(), ast_copy_string(), ast_free, AST_LIST_HEAD_NOLOCK_INIT_VALUE, AST_LIST_REMOVE_HEAD, ast_search_dns(), ast_verb, context, srv_entry::host, srv_entry::list, srv_entry::port, process_weights(), and srv_callback().
Referenced by ast_get_ip_or_srv(), and create_addr().
00260 { 00261 struct srv_context context = { .entries = AST_LIST_HEAD_NOLOCK_INIT_VALUE }; 00262 struct srv_entry *current; 00263 int ret; 00264 00265 if (chan && ast_autoservice_start(chan) < 0) { 00266 return -1; 00267 } 00268 00269 ret = ast_search_dns(&context, service, C_IN, T_SRV, srv_callback); 00270 00271 if (context.have_weights) { 00272 process_weights(&context); 00273 } 00274 00275 if (chan) { 00276 ret |= ast_autoservice_stop(chan); 00277 } 00278 00279 /* TODO: there could be a "." entry in the returned list of 00280 answers... if so, this requires special handling */ 00281 00282 /* the list of entries will be sorted in the proper selection order 00283 already, so we just need the first one (if any) */ 00284 00285 if ((ret > 0) && (current = AST_LIST_REMOVE_HEAD(&context.entries, list))) { 00286 ast_copy_string(host, current->host, hostlen); 00287 *port = current->port; 00288 ast_free(current); 00289 ast_verb(4, "ast_get_srv: SRV lookup for '%s' mapped to host %s, port %d\n", 00290 service, host, *port); 00291 } else { 00292 host[0] = '\0'; 00293 *port = -1; 00294 } 00295 00296 while ((current = AST_LIST_REMOVE_HEAD(&context.entries, list))) { 00297 ast_free(current); 00298 } 00299 00300 return ret; 00301 }
void ast_srv_cleanup | ( | struct srv_context ** | context | ) |
Cleanup resources associated with ast_srv_lookup.
context | Pointer passed into ast_srv_lookup |
Definition at line 247 of file srv.c.
References ast_srv_lookup(), context, and srv_entry::port.
Referenced by launch_ha_netscript(), srds_destroy_cb(), and srv_datastore_setup().
00248 { 00249 const char *host; 00250 unsigned short port; 00251 00252 if (*context) { 00253 /* We have a context to clean up. */ 00254 while (!(ast_srv_lookup(context, NULL, &host, &port))) { 00255 } 00256 } 00257 }
int ast_srv_get_nth_record | ( | struct srv_context * | context, | |
int | record_num, | |||
const char ** | host, | |||
unsigned short * | port, | |||
unsigned short * | priority, | |||
unsigned short * | weight | |||
) |
Retrieve details from a specific SRV record.
After calling ast_srv_lookup, the srv_context will contain the data from several records. You can retrieve the data of a specific one by asking for a specific record number. The records are sorted based on priority and secondarily based on weight. See RFC 2782 for the exact sorting rules.
context | The context returned by ast_srv_lookup | |
record_num | The 1-indexed record number to retrieve | |
[out] | host | The host portion of the record |
[out] | port | The port portion of the record |
[out] | priority | The priority portion of the record |
[out] | weight | The weight portion of the record |
-1 | Failed to retrieve information. Likely due to an out of range record_num | |
0 | Success |
Definition at line 308 of file srv.c.
References AST_LIST_TRAVERSE, context, srv_entry::host, srv_entry::list, srv_entry::port, srv_entry::priority, and srv_entry::weight.
Referenced by srv_result_read().
00310 { 00311 int i = 1; 00312 int res = -1; 00313 struct srv_entry *entry; 00314 00315 if (record_num < 1 || record_num > context->num_records) { 00316 return res; 00317 } 00318 00319 AST_LIST_TRAVERSE(&context->entries, entry, list) { 00320 if (i == record_num) { 00321 *host = entry->host; 00322 *port = entry->port; 00323 *priority = entry->priority; 00324 *weight = entry->weight; 00325 res = 0; 00326 break; 00327 } 00328 ++i; 00329 } 00330 00331 return res; 00332 }
unsigned int ast_srv_get_record_count | ( | struct srv_context * | context | ) |
Get the number of records for a given SRV context.
This is meant to be used after calling ast_srv_lookup, so that one may retrieve the number of records returned during a specific SRV lookup.
context | The context returned by ast_srv_lookup |
Definition at line 303 of file srv.c.
References context.
Referenced by srv_result_read().
00304 { 00305 return context->num_records; 00306 }
int ast_srv_lookup | ( | struct srv_context ** | context, | |
const char * | service, | |||
const char ** | host, | |||
unsigned short * | port | |||
) |
Retrieve set of SRV lookups, in order.
[in] | context | A pointer in which to hold the result |
[in] | service | The service name to look up |
[out] | host | Result host |
[out] | port | Associated TCP portnum |
-1 | Query failed | |
0 | Result exists in host and port | |
1 | No more results |
Definition at line 202 of file srv.c.
References ast_calloc, ast_free, AST_LIST_FIRST, AST_LIST_HEAD_INIT_NOLOCK, AST_LIST_NEXT, AST_LIST_REMOVE_HEAD, AST_LIST_TRAVERSE, ast_search_dns(), context, srv_entry::list, process_weights(), and srv_callback().
Referenced by ast_srv_cleanup(), launch_ha_netscript(), and srv_datastore_setup().
00203 { 00204 struct srv_entry *cur; 00205 00206 if (*context == NULL) { 00207 if (!(*context = ast_calloc(1, sizeof(struct srv_context)))) { 00208 return -1; 00209 } 00210 AST_LIST_HEAD_INIT_NOLOCK(&(*context)->entries); 00211 00212 if ((ast_search_dns(*context, service, C_IN, T_SRV, srv_callback)) < 0) { 00213 ast_free(*context); 00214 *context = NULL; 00215 return -1; 00216 } 00217 00218 if ((*context)->have_weights) { 00219 process_weights(*context); 00220 } 00221 00222 (*context)->prev = AST_LIST_FIRST(&(*context)->entries); 00223 *host = (*context)->prev->host; 00224 *port = (*context)->prev->port; 00225 AST_LIST_TRAVERSE(&(*context)->entries, cur, list) { 00226 ++((*context)->num_records); 00227 } 00228 return 0; 00229 } 00230 00231 if (((*context)->prev = AST_LIST_NEXT((*context)->prev, list))) { 00232 /* Retrieve next item in result */ 00233 *host = (*context)->prev->host; 00234 *port = (*context)->prev->port; 00235 return 0; 00236 } else { 00237 /* No more results */ 00238 while ((cur = AST_LIST_REMOVE_HEAD(&(*context)->entries, list))) { 00239 ast_free(cur); 00240 } 00241 ast_free(*context); 00242 *context = NULL; 00243 return 1; 00244 } 00245 }
static int parse_srv | ( | unsigned char * | answer, | |
int | len, | |||
unsigned char * | msg, | |||
struct srv_entry ** | result | |||
) | [static] |
Definition at line 72 of file srv.c.
References ast_calloc, ast_log(), LOG_WARNING, srv_entry::port, srv_entry::priority, and srv_entry::weight.
Referenced by srv_callback().
00073 { 00074 struct srv { 00075 unsigned short priority; 00076 unsigned short weight; 00077 unsigned short port; 00078 } __attribute__((__packed__)) *srv = (struct srv *) answer; 00079 00080 int res = 0; 00081 char repl[256] = ""; 00082 struct srv_entry *entry; 00083 00084 if (len < sizeof(*srv)) 00085 return -1; 00086 00087 answer += sizeof(*srv); 00088 len -= sizeof(*srv); 00089 00090 if ((res = dn_expand(msg, answer + len, answer, repl, sizeof(repl) - 1)) <= 0) { 00091 ast_log(LOG_WARNING, "Failed to expand hostname\n"); 00092 return -1; 00093 } 00094 00095 /* the magic value "." for the target domain means that this service 00096 is *NOT* available at the domain we searched */ 00097 if (!strcmp(repl, ".")) 00098 return -1; 00099 00100 if (!(entry = ast_calloc(1, sizeof(*entry) + strlen(repl)))) 00101 return -1; 00102 00103 entry->priority = ntohs(srv->priority); 00104 entry->weight = ntohs(srv->weight); 00105 entry->port = ntohs(srv->port); 00106 strcpy(entry->host, repl); 00107 00108 *result = entry; 00109 00110 return 0; 00111 }
static void process_weights | ( | struct srv_context * | context | ) | [static] |
Definition at line 150 of file srv.c.
References AST_LIST_APPEND_LIST, AST_LIST_FIRST, AST_LIST_HEAD_NOLOCK_INIT_VALUE, AST_LIST_MOVE_CURRENT, AST_LIST_TRAVERSE, AST_LIST_TRAVERSE_SAFE_BEGIN, AST_LIST_TRAVERSE_SAFE_END, ast_random(), context, srv_entry::list, srv_entry::priority, srv_entry::weight, and srv_entry::weight_sum.
Referenced by ast_get_srv(), and ast_srv_lookup().
00151 { 00152 struct srv_entry *current; 00153 struct srv_entries newlist = AST_LIST_HEAD_NOLOCK_INIT_VALUE; 00154 00155 while (AST_LIST_FIRST(&context->entries)) { 00156 unsigned int random_weight; 00157 unsigned int weight_sum; 00158 unsigned short cur_priority = AST_LIST_FIRST(&context->entries)->priority; 00159 struct srv_entries temp_list = AST_LIST_HEAD_NOLOCK_INIT_VALUE; 00160 weight_sum = 0; 00161 00162 AST_LIST_TRAVERSE_SAFE_BEGIN(&context->entries, current, list) { 00163 if (current->priority != cur_priority) 00164 break; 00165 00166 AST_LIST_MOVE_CURRENT(&temp_list, list); 00167 } 00168 AST_LIST_TRAVERSE_SAFE_END; 00169 00170 while (AST_LIST_FIRST(&temp_list)) { 00171 weight_sum = 0; 00172 AST_LIST_TRAVERSE(&temp_list, current, list) 00173 current->weight_sum = weight_sum += current->weight; 00174 00175 /* if all the remaining entries have weight == 0, 00176 then just append them to the result list and quit */ 00177 if (weight_sum == 0) { 00178 AST_LIST_APPEND_LIST(&newlist, &temp_list, list); 00179 break; 00180 } 00181 00182 random_weight = 1 + (unsigned int) ((float) weight_sum * (ast_random() / ((float) RAND_MAX + 1.0))); 00183 00184 AST_LIST_TRAVERSE_SAFE_BEGIN(&temp_list, current, list) { 00185 if (current->weight < random_weight) 00186 continue; 00187 00188 AST_LIST_MOVE_CURRENT(&newlist, list); 00189 break; 00190 } 00191 AST_LIST_TRAVERSE_SAFE_END; 00192 } 00193 00194 } 00195 00196 /* now that the new list has been ordered, 00197 put it in place */ 00198 00199 AST_LIST_APPEND_LIST(&context->entries, &newlist, list); 00200 }
static int srv_callback | ( | void * | context, | |
unsigned char * | answer, | |||
int | len, | |||
unsigned char * | fullanswer | |||
) | [static] |
Definition at line 113 of file srv.c.
References AST_LIST_INSERT_BEFORE_CURRENT, AST_LIST_INSERT_TAIL, AST_LIST_TRAVERSE_SAFE_BEGIN, AST_LIST_TRAVERSE_SAFE_END, srv_context::entries, srv_context::have_weights, srv_entry::list, parse_srv(), srv_entry::priority, and srv_entry::weight.
Referenced by ast_get_srv(), and ast_srv_lookup().
00114 { 00115 struct srv_context *c = (struct srv_context *) context; 00116 struct srv_entry *entry = NULL; 00117 struct srv_entry *current; 00118 00119 if (parse_srv(answer, len, fullanswer, &entry)) 00120 return -1; 00121 00122 if (entry->weight) 00123 c->have_weights = 1; 00124 00125 AST_LIST_TRAVERSE_SAFE_BEGIN(&c->entries, current, list) { 00126 /* insert this entry just before the first existing 00127 entry with a higher priority */ 00128 if (current->priority <= entry->priority) 00129 continue; 00130 00131 AST_LIST_INSERT_BEFORE_CURRENT(entry, list); 00132 entry = NULL; 00133 break; 00134 } 00135 AST_LIST_TRAVERSE_SAFE_END; 00136 00137 /* if we didn't find a place to insert the entry before an existing 00138 entry, then just add it to the end */ 00139 if (entry) 00140 AST_LIST_INSERT_TAIL(&c->entries, entry, list); 00141 00142 return 0; 00143 }