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00029 #include <sys/types.h>
00030 #include <netinet/in.h>
00031 #include <arpa/nameser.h>
00032 #if __APPLE_CC__ >= 1495
00033 #include <arpa/nameser_compat.h>
00034 #endif
00035 #include <resolv.h>
00036 #include <stdio.h>
00037 #include <string.h>
00038 #include <unistd.h>
00039
00040 #include "asterisk.h"
00041
00042 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 7221 $")
00043
00044 #include "asterisk/channel.h"
00045 #include "asterisk/logger.h"
00046 #include "asterisk/srv.h"
00047 #include "asterisk/dns.h"
00048 #include "asterisk/options.h"
00049 #include "asterisk/utils.h"
00050
00051 #ifdef __APPLE__
00052 #undef T_SRV
00053 #define T_SRV 33
00054 #endif
00055
00056 struct srv {
00057 unsigned short priority;
00058 unsigned short weight;
00059 unsigned short portnum;
00060 } __attribute__ ((__packed__));
00061
00062 static int parse_srv(char *host, int hostlen, int *portno, char *answer, int len, char *msg)
00063 {
00064 int res = 0;
00065 struct srv *srv = (struct srv *)answer;
00066 char repl[256] = "";
00067
00068 if (len < sizeof(struct srv)) {
00069 printf("Length too short\n");
00070 return -1;
00071 }
00072 answer += sizeof(struct srv);
00073 len -= sizeof(struct srv);
00074
00075 if ((res = dn_expand((unsigned char *)msg, (unsigned char *)answer + len, (unsigned char *)answer, repl, sizeof(repl) - 1)) < 0) {
00076 ast_log(LOG_WARNING, "Failed to expand hostname\n");
00077 return -1;
00078 }
00079 if (res && strcmp(repl, ".")) {
00080 if (option_verbose > 3)
00081 ast_verbose( VERBOSE_PREFIX_3 "parse_srv: SRV mapped to host %s, port %d\n", repl, ntohs(srv->portnum));
00082 if (host) {
00083 ast_copy_string(host, repl, hostlen);
00084 host[hostlen-1] = '\0';
00085 }
00086 if (portno)
00087 *portno = ntohs(srv->portnum);
00088 return 0;
00089 }
00090 return -1;
00091 }
00092
00093 struct srv_context {
00094 char *host;
00095 int hostlen;
00096 int *port;
00097 };
00098
00099 static int srv_callback(void *context, char *answer, int len, char *fullanswer)
00100 {
00101 struct srv_context *c = (struct srv_context *)context;
00102
00103 if (parse_srv(c->host, c->hostlen, c->port, answer, len, fullanswer)) {
00104 ast_log(LOG_WARNING, "Failed to parse srv\n");
00105 return -1;
00106 }
00107
00108 if (!ast_strlen_zero(c->host))
00109 return 1;
00110
00111 return 0;
00112 }
00113
00114 int ast_get_srv(struct ast_channel *chan, char *host, int hostlen, int *port, const char *service)
00115 {
00116 struct srv_context context;
00117 int ret;
00118
00119 context.host = host;
00120 context.hostlen = hostlen;
00121 context.port = port;
00122
00123 if (chan && ast_autoservice_start(chan) < 0)
00124 return -1;
00125
00126 ret = ast_search_dns(&context, service, C_IN, T_SRV, srv_callback);
00127
00128 if (chan)
00129 ret |= ast_autoservice_stop(chan);
00130
00131 if (ret <= 0) {
00132 host[0] = '\0';
00133 *port = -1;
00134 return ret;
00135 }
00136 return ret;
00137 }