#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 263 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().
00264 { 00265 struct srv_context context = { .entries = AST_LIST_HEAD_NOLOCK_INIT_VALUE }; 00266 struct srv_entry *current; 00267 int ret; 00268 00269 if (chan && ast_autoservice_start(chan) < 0) { 00270 return -1; 00271 } 00272 00273 ret = ast_search_dns(&context, service, C_IN, T_SRV, srv_callback); 00274 00275 if (context.have_weights) { 00276 process_weights(&context); 00277 } 00278 00279 if (chan) { 00280 ret |= ast_autoservice_stop(chan); 00281 } 00282 00283 /* TODO: there could be a "." entry in the returned list of 00284 answers... if so, this requires special handling */ 00285 00286 /* the list of entries will be sorted in the proper selection order 00287 already, so we just need the first one (if any) */ 00288 00289 if ((ret > 0) && (current = AST_LIST_REMOVE_HEAD(&context.entries, list))) { 00290 ast_copy_string(host, current->host, hostlen); 00291 *port = current->port; 00292 ast_free(current); 00293 ast_verb(4, "ast_get_srv: SRV lookup for '%s' mapped to host %s, port %d\n", 00294 service, host, *port); 00295 } else { 00296 host[0] = '\0'; 00297 *port = -1; 00298 } 00299 00300 while ((current = AST_LIST_REMOVE_HEAD(&context.entries, list))) { 00301 ast_free(current); 00302 } 00303 00304 return ret; 00305 }
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 251 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().
00252 { 00253 const char *host; 00254 unsigned short port; 00255 00256 if (*context) { 00257 /* We have a context to clean up. */ 00258 while (!(ast_srv_lookup(context, NULL, &host, &port))) { 00259 } 00260 } 00261 }
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 312 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().
00314 { 00315 int i = 1; 00316 int res = -1; 00317 struct srv_entry *entry; 00318 00319 if (record_num < 1 || record_num > context->num_records) { 00320 return res; 00321 } 00322 00323 AST_LIST_TRAVERSE(&context->entries, entry, list) { 00324 if (i == record_num) { 00325 *host = entry->host; 00326 *port = entry->port; 00327 *priority = entry->priority; 00328 *weight = entry->weight; 00329 res = 0; 00330 break; 00331 } 00332 ++i; 00333 } 00334 00335 return res; 00336 }
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 307 of file srv.c.
References context.
Referenced by srv_result_read().
00308 { 00309 return context->num_records; 00310 }
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 206 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().
00207 { 00208 struct srv_entry *cur; 00209 00210 if (*context == NULL) { 00211 if (!(*context = ast_calloc(1, sizeof(struct srv_context)))) { 00212 return -1; 00213 } 00214 AST_LIST_HEAD_INIT_NOLOCK(&(*context)->entries); 00215 00216 if ((ast_search_dns(*context, service, C_IN, T_SRV, srv_callback)) < 0) { 00217 ast_free(*context); 00218 *context = NULL; 00219 return -1; 00220 } 00221 00222 if ((*context)->have_weights) { 00223 process_weights(*context); 00224 } 00225 00226 (*context)->prev = AST_LIST_FIRST(&(*context)->entries); 00227 *host = (*context)->prev->host; 00228 *port = (*context)->prev->port; 00229 AST_LIST_TRAVERSE(&(*context)->entries, cur, list) { 00230 ++((*context)->num_records); 00231 } 00232 return 0; 00233 } 00234 00235 if (((*context)->prev = AST_LIST_NEXT((*context)->prev, list))) { 00236 /* Retrieve next item in result */ 00237 *host = (*context)->prev->host; 00238 *port = (*context)->prev->port; 00239 return 0; 00240 } else { 00241 /* No more results */ 00242 while ((cur = AST_LIST_REMOVE_HEAD(&(*context)->entries, list))) { 00243 ast_free(cur); 00244 } 00245 ast_free(*context); 00246 *context = NULL; 00247 return 1; 00248 } 00249 }
static int parse_srv | ( | unsigned char * | answer, | |
int | len, | |||
unsigned char * | msg, | |||
struct srv_entry ** | result | |||
) | [static] |
Definition at line 76 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().
00077 { 00078 struct srv { 00079 unsigned short priority; 00080 unsigned short weight; 00081 unsigned short port; 00082 } __attribute__((__packed__)) *srv = (struct srv *) answer; 00083 00084 int res = 0; 00085 char repl[256] = ""; 00086 struct srv_entry *entry; 00087 00088 if (len < sizeof(*srv)) 00089 return -1; 00090 00091 answer += sizeof(*srv); 00092 len -= sizeof(*srv); 00093 00094 if ((res = dn_expand(msg, answer + len, answer, repl, sizeof(repl) - 1)) <= 0) { 00095 ast_log(LOG_WARNING, "Failed to expand hostname\n"); 00096 return -1; 00097 } 00098 00099 /* the magic value "." for the target domain means that this service 00100 is *NOT* available at the domain we searched */ 00101 if (!strcmp(repl, ".")) 00102 return -1; 00103 00104 if (!(entry = ast_calloc(1, sizeof(*entry) + strlen(repl)))) 00105 return -1; 00106 00107 entry->priority = ntohs(srv->priority); 00108 entry->weight = ntohs(srv->weight); 00109 entry->port = ntohs(srv->port); 00110 strcpy(entry->host, repl); 00111 00112 *result = entry; 00113 00114 return 0; 00115 }
static void process_weights | ( | struct srv_context * | context | ) | [static] |
Definition at line 154 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().
00155 { 00156 struct srv_entry *current; 00157 struct srv_entries newlist = AST_LIST_HEAD_NOLOCK_INIT_VALUE; 00158 00159 while (AST_LIST_FIRST(&context->entries)) { 00160 unsigned int random_weight; 00161 unsigned int weight_sum; 00162 unsigned short cur_priority = AST_LIST_FIRST(&context->entries)->priority; 00163 struct srv_entries temp_list = AST_LIST_HEAD_NOLOCK_INIT_VALUE; 00164 weight_sum = 0; 00165 00166 AST_LIST_TRAVERSE_SAFE_BEGIN(&context->entries, current, list) { 00167 if (current->priority != cur_priority) 00168 break; 00169 00170 AST_LIST_MOVE_CURRENT(&temp_list, list); 00171 } 00172 AST_LIST_TRAVERSE_SAFE_END; 00173 00174 while (AST_LIST_FIRST(&temp_list)) { 00175 weight_sum = 0; 00176 AST_LIST_TRAVERSE(&temp_list, current, list) 00177 current->weight_sum = weight_sum += current->weight; 00178 00179 /* if all the remaining entries have weight == 0, 00180 then just append them to the result list and quit */ 00181 if (weight_sum == 0) { 00182 AST_LIST_APPEND_LIST(&newlist, &temp_list, list); 00183 break; 00184 } 00185 00186 random_weight = 1 + (unsigned int) ((float) weight_sum * (ast_random() / ((float) RAND_MAX + 1.0))); 00187 00188 AST_LIST_TRAVERSE_SAFE_BEGIN(&temp_list, current, list) { 00189 if (current->weight < random_weight) 00190 continue; 00191 00192 AST_LIST_MOVE_CURRENT(&newlist, list); 00193 break; 00194 } 00195 AST_LIST_TRAVERSE_SAFE_END; 00196 } 00197 00198 } 00199 00200 /* now that the new list has been ordered, 00201 put it in place */ 00202 00203 AST_LIST_APPEND_LIST(&context->entries, &newlist, list); 00204 }
static int srv_callback | ( | void * | context, | |
unsigned char * | answer, | |||
int | len, | |||
unsigned char * | fullanswer | |||
) | [static] |
Definition at line 117 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().
00118 { 00119 struct srv_context *c = (struct srv_context *) context; 00120 struct srv_entry *entry = NULL; 00121 struct srv_entry *current; 00122 00123 if (parse_srv(answer, len, fullanswer, &entry)) 00124 return -1; 00125 00126 if (entry->weight) 00127 c->have_weights = 1; 00128 00129 AST_LIST_TRAVERSE_SAFE_BEGIN(&c->entries, current, list) { 00130 /* insert this entry just before the first existing 00131 entry with a higher priority */ 00132 if (current->priority <= entry->priority) 00133 continue; 00134 00135 AST_LIST_INSERT_BEFORE_CURRENT(entry, list); 00136 entry = NULL; 00137 break; 00138 } 00139 AST_LIST_TRAVERSE_SAFE_END; 00140 00141 /* if we didn't find a place to insert the entry before an existing 00142 entry, then just add it to the end */ 00143 if (entry) 00144 AST_LIST_INSERT_TAIL(&c->entries, entry, list); 00145 00146 return 0; 00147 }