#include "asterisk.h"
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "asterisk/channel.h"
#include "asterisk/logger.h"
#include "asterisk/srv.h"
#include "asterisk/dns.h"
#include "asterisk/options.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) |
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 206 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_verbose(), context, srv_entry::host, srv_entry::list, option_verbose, srv_entry::port, process_weights(), srv_callback(), and VERBOSE_PREFIX_3.
Referenced by ast_get_ip_or_srv(), and create_addr().
00207 { 00208 struct srv_context context = { .entries = AST_LIST_HEAD_NOLOCK_INIT_VALUE }; 00209 struct srv_entry *current; 00210 int ret; 00211 00212 if (chan && ast_autoservice_start(chan) < 0) 00213 return -1; 00214 00215 ret = ast_search_dns(&context, service, C_IN, T_SRV, srv_callback); 00216 00217 if (context.have_weights) 00218 process_weights(&context); 00219 00220 if (chan) 00221 ret |= ast_autoservice_stop(chan); 00222 00223 /* TODO: there could be a "." entry in the returned list of 00224 answers... if so, this requires special handling */ 00225 00226 /* the list of entries will be sorted in the proper selection order 00227 already, so we just need the first one (if any) */ 00228 00229 if ((ret > 0) && (current = AST_LIST_REMOVE_HEAD(&context.entries, list))) { 00230 ast_copy_string(host, current->host, hostlen); 00231 *port = current->port; 00232 ast_free(current); 00233 if (option_verbose > 3) { 00234 ast_verbose(VERBOSE_PREFIX_3 "ast_get_srv: SRV lookup for '%s' mapped to host %s, port %d\n", 00235 service, host, *port); 00236 } 00237 } else { 00238 host[0] = '\0'; 00239 *port = -1; 00240 } 00241 00242 while ((current = AST_LIST_REMOVE_HEAD(&context.entries, list))) 00243 ast_free(current); 00244 00245 return ret; 00246 }
static int parse_srv | ( | unsigned char * | answer, | |
int | len, | |||
unsigned char * | msg, | |||
struct srv_entry ** | result | |||
) | [static] |
Definition at line 74 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().
00075 { 00076 struct srv { 00077 unsigned short priority; 00078 unsigned short weight; 00079 unsigned short port; 00080 } __attribute__((__packed__)) *srv = (struct srv *) answer; 00081 00082 int res = 0; 00083 char repl[256] = ""; 00084 struct srv_entry *entry; 00085 00086 if (len < sizeof(*srv)) 00087 return -1; 00088 00089 answer += sizeof(*srv); 00090 len -= sizeof(*srv); 00091 00092 if ((res = dn_expand(msg, answer + len, answer, repl, sizeof(repl) - 1)) <= 0) { 00093 ast_log(LOG_WARNING, "Failed to expand hostname\n"); 00094 return -1; 00095 } 00096 00097 /* the magic value "." for the target domain means that this service 00098 is *NOT* available at the domain we searched */ 00099 if (!strcmp(repl, ".")) 00100 return -1; 00101 00102 if (!(entry = ast_calloc(1, sizeof(*entry) + strlen(repl)))) 00103 return -1; 00104 00105 entry->priority = ntohs(srv->priority); 00106 entry->weight = ntohs(srv->weight); 00107 entry->port = ntohs(srv->port); 00108 strcpy(entry->host, repl); 00109 00110 *result = entry; 00111 00112 return 0; 00113 }
static void process_weights | ( | struct srv_context * | context | ) | [static] |
Definition at line 152 of file srv.c.
References AST_LIST_APPEND_LIST, AST_LIST_FIRST, AST_LIST_HEAD_NOLOCK_INIT_VALUE, AST_LIST_INSERT_TAIL, AST_LIST_REMOVE_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().
00153 { 00154 struct srv_entry *current; 00155 struct srv_entries newlist = AST_LIST_HEAD_NOLOCK_INIT_VALUE; 00156 00157 while (AST_LIST_FIRST(&context->entries)) { 00158 unsigned int random_weight; 00159 unsigned int weight_sum; 00160 unsigned short cur_priority = AST_LIST_FIRST(&context->entries)->priority; 00161 struct srv_entries temp_list = AST_LIST_HEAD_NOLOCK_INIT_VALUE; 00162 weight_sum = 0; 00163 00164 AST_LIST_TRAVERSE_SAFE_BEGIN(&context->entries, current, list) { 00165 if (current->priority != cur_priority) 00166 break; 00167 00168 AST_LIST_REMOVE_CURRENT(&context->entries, list); 00169 AST_LIST_INSERT_TAIL(&temp_list, current, list); 00170 } 00171 AST_LIST_TRAVERSE_SAFE_END; 00172 00173 while (AST_LIST_FIRST(&temp_list)) { 00174 weight_sum = 0; 00175 AST_LIST_TRAVERSE(&temp_list, current, list) 00176 current->weight_sum = weight_sum += current->weight; 00177 00178 /* if all the remaining entries have weight == 0, 00179 then just append them to the result list and quit */ 00180 if (weight_sum == 0) { 00181 AST_LIST_APPEND_LIST(&newlist, &temp_list, list); 00182 break; 00183 } 00184 00185 random_weight = 1 + (unsigned int) ((float) weight_sum * (ast_random() / ((float) RAND_MAX + 1.0))); 00186 00187 AST_LIST_TRAVERSE_SAFE_BEGIN(&temp_list, current, list) { 00188 if (current->weight < random_weight) 00189 continue; 00190 00191 AST_LIST_REMOVE_CURRENT(&temp_list, list); 00192 AST_LIST_INSERT_TAIL(&newlist, current, 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 115 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().
00116 { 00117 struct srv_context *c = (struct srv_context *) context; 00118 struct srv_entry *entry = NULL; 00119 struct srv_entry *current; 00120 00121 if (parse_srv(answer, len, fullanswer, &entry)) 00122 return -1; 00123 00124 if (entry->weight) 00125 c->have_weights = 1; 00126 00127 AST_LIST_TRAVERSE_SAFE_BEGIN(&c->entries, current, list) { 00128 /* insert this entry just before the first existing 00129 entry with a higher priority */ 00130 if (current->priority <= entry->priority) 00131 continue; 00132 00133 AST_LIST_INSERT_BEFORE_CURRENT(&c->entries, entry, list); 00134 entry = NULL; 00135 break; 00136 } 00137 AST_LIST_TRAVERSE_SAFE_END; 00138 00139 /* if we didn't find a place to insert the entry before an existing 00140 entry, then just add it to the end */ 00141 if (entry) 00142 AST_LIST_INSERT_TAIL(&c->entries, entry, list); 00143 00144 return 1; 00145 }