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Create iterative method for querying SRV results, and use that for finding AGI servers.

Browse Source 
(closes issue #14775)
 Reported by: _brent_
 Patches: 
       20091215__issue14775.diff.txt uploaded by tilghman (license 14)
       hagi-5.patch uploaded by brent (license 388)
 Tested by: _brent_
 Reviewboard: https://reviewboard.asterisk.org/r/378/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@241188 65c4cc65-6c06-0410-ace0-fbb531ad65f3
certified/1.8.6
Tilghman Lesher 16 years ago
parent 800313cbd9
commit 49bf540c71
4 changed files with 162 additions and 18 deletions
Show Stats Download Patch File Download Diff File

5
CHANGES
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@ -1325,6 +1325,11 @@ AGI Changes
* If app_stack is loaded, GOSUB is a native AGI command that may be used to
invoke subroutines in the dialplan. Note that calling EXEC with Gosub
does not behave as expected; the native command needs to be used, instead.
* Added the ability to perform SRV lookups on fast AGI calls. To use this
feature, simply use hagi: instead of agi: as the protocol portion
of the URI parameter to the AGI function call in your dial plan. Also note
that specifying a port number in the AGI URI will disable SRV lookups,
even if you use the hagi: protocol.
Logger changes
--------------

19
include/asterisk/srv.h
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@ -31,6 +31,25 @@
no provisions for retrying or failover between records.
*/
/*!\brief An opaque type, for lookup usage */
struct srv_context;
/*!\brief Retrieve set of SRV lookups, in order
* \param[in] context A pointer in which to hold the result
* \param[in] service The service name to look up
* \param[out] host Result host
* \param[out] port Associated TCP portnum
* \retval -1 Query failed
* \retval 0 Result exists in host and port
* \retval 1 No more results
*/
extern int ast_srv_lookup(struct srv_context **context, const char *service, const char **host, unsigned short *port);
/*!\brief Cleanup resources associated with ast_srv_lookup
* \param context Pointer passed into ast_srv_lookup
*/
void ast_srv_cleanup(struct srv_context **context);
/*! Lookup entry in SRV records Returns 1 if found, 0 if not found, -1 on hangup
Only do SRV record lookup if you get a domain without a port. If you get a port #, it's a DNS host name.
*/

50
main/srv.c
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@ -64,6 +64,7 @@ struct srv_entry {
struct srv_context {
unsigned int have_weights:1;
struct srv_entry *prev;
AST_LIST_HEAD_NOLOCK(srv_entries, srv_entry) entries;
};
@ -197,6 +198,55 @@ static void process_weights(struct srv_context *context)
AST_LIST_APPEND_LIST(&context->entries, &newlist, list);
}
int ast_srv_lookup(struct srv_context **context, const char *service, const char **host, unsigned short *port)
{
struct srv_entry *cur;
if (*context == NULL) {
if (!(*context = ast_calloc(1, sizeof(struct srv_context)))) {
return -1;
}
AST_LIST_HEAD_INIT_NOLOCK(&(*context)->entries);
if ((ast_search_dns(*context, service, C_IN, T_SRV, srv_callback)) < 0) {
ast_free(*context);
*context = NULL;
return -1;
}
if ((*context)->have_weights) {
process_weights(*context);
}
(*context)->prev = AST_LIST_FIRST(&(*context)->entries);
*host = (*context)->prev->host;
*port = (*context)->prev->port;
return 0;
}
if (((*context)->prev = AST_LIST_NEXT((*context)->prev, list))) {
/* Retrieve next item in result */
*host = (*context)->prev->host;
*port = (*context)->prev->port;
return 0;
} else {
/* No more results */
while ((cur = AST_LIST_REMOVE_HEAD(&(*context)->entries, list))) {
ast_free(cur);
}
ast_free(*context);
*context = NULL;
return 1;
}
}
void ast_srv_cleanup(struct srv_context **context)
{
const char *host;
unsigned short port;
while (!(ast_srv_lookup(context, NULL, &host, &port)));
}
int ast_get_srv(struct ast_channel *chan, char *host, int hostlen, int *port, const char *service)
{
struct srv_context context = { .entries = AST_LIST_HEAD_NOLOCK_INIT_VALUE };

106
res/res_agi.c
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@ -60,6 +60,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include "asterisk/features.h"
#include "asterisk/term.h"
#include "asterisk/xmldoc.h"
#include "asterisk/srv.h"
#define AST_API_MODULE
#include "asterisk/agi.h"
@ -897,6 +898,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#define MAX_CMD_LEN 80
#define AGI_NANDFS_RETRY 3
#define AGI_BUF_LEN 2048
#define SRV_PREFIX "_agi._tcp."
static char *app = "AGI";
@ -1339,32 +1341,28 @@ quit:
/* launch_netscript: The fastagi handler.
FastAGI defaults to port 4573 */
static enum agi_result launch_netscript(char *agiurl, char *argv[], int *fds, int *efd, int *opid)
static enum agi_result launch_netscript(char *agiurl, char *argv[], int *fds)
{
int s, flags, res, port = AGI_PORT;
struct pollfd pfds[1];
char *host, *c, *script = "";
char *host, *c, *script;
struct sockaddr_in addr_in;
struct hostent *hp;
struct ast_hostent ahp;
/* agiusl is "agi://host.domain[:port][/script/name]" */
/* agiurl is "agi://host.domain[:port][/script/name]" */
host = ast_strdupa(agiurl + 6); /* Remove agi:// */
/* Strip off any script name */
if ((c = strchr(host, '/'))) {
*c = '\0';
c++;
script = c;
if ((script = strchr(host, '/'))) {
*script++ = '\0';
} else {
script = "";
}
if ((c = strchr(host, ':'))) {
*c = '\0';
c++;
*c++ = '\0';
port = atoi(c);
}
if (efd) {
ast_log(LOG_WARNING, "AGI URI's don't support Enhanced AGI yet\n");
return -1;
}
if (!(hp = ast_gethostbyname(host, &ahp))) {
ast_log(LOG_WARNING, "Unable to locate host '%s'\n", host);
return -1;
@ -1423,20 +1421,92 @@ static enum agi_result launch_netscript(char *agiurl, char *argv[], int *fds, in
ast_debug(4, "Wow, connected!\n");
fds[0] = s;
fds[1] = s;
*opid = -1;
return AGI_RESULT_SUCCESS_FAST;
}
/*!
* \internal
* \brief The HA fastagi handler.
* \param agiurl The request URL as passed to Agi() in the dial plan
* \param argv The parameters after the URL passed to Agi() in the dial plan
* \param fds Input/output file descriptors
*
* Uses SRV lookups to try to connect to a list of FastAGI servers. The hostname in
* the URI is prefixed with _agi._tcp. prior to the DNS resolution. For
* example, if you specify the URI \a hagi://agi.example.com/foo.agi the DNS
* query would be for \a _agi._tcp.agi.example.com and you'll need to make sure
* this resolves.
*
* This function parses the URI, resolves the SRV service name, forms new URIs
* with the results of the DNS lookup, and then calls launch_netscript on the
* new URIs until one succeeds.
*
* \return the result of the AGI operation.
*/
static enum agi_result launch_ha_netscript(char *agiurl, char *argv[], int *fds)
{
char *host, *script;
enum agi_result result = AGI_RESULT_FAILURE;
struct srv_context *context = NULL;
int srv_ret;
char service[256];
char resolved_uri[1024];
const char *srvhost;
unsigned short srvport;
/* format of agiurl is "hagi://host.domain[:port][/script/name]" */
if (!(host = ast_strdupa(agiurl + 7))) { /* Remove hagi:// */
ast_log(LOG_WARNING, "An error occurred parsing the AGI URI: %s", agiurl);
return AGI_RESULT_FAILURE;
}
/* Strip off any script name */
if ((script = strchr(host, '/'))) {
*script++ = '\0';
} else {
script = "";
}
if (strchr(host, ':')) {
ast_log(LOG_WARNING, "Specifying a port number disables SRV lookups: %s\n", agiurl);
return launch_netscript(agiurl + 1, argv, fds); /* +1 to strip off leading h from hagi:// */
}
snprintf(service, sizeof(service), "%s%s", SRV_PREFIX, host);
while (!(srv_ret = ast_srv_lookup(&context, service, &srvhost, &srvport))) {
snprintf(resolved_uri, sizeof(resolved_uri), "agi://%s:%d/%s", srvhost, srvport, script);
result = launch_netscript(resolved_uri, argv, fds);
if (result == AGI_RESULT_FAILURE || result == AGI_RESULT_NOTFOUND) {
ast_log(LOG_WARNING, "AGI request failed for host '%s' (%s:%d)\n", host, srvhost, srvport);
} else {
break;
}
}
if (srv_ret < 0) {
ast_log(LOG_WARNING, "SRV lookup failed for %s\n", agiurl);
} else {
ast_srv_cleanup(&context);
}
return result;
}
static enum agi_result launch_script(struct ast_channel *chan, char *script, char *argv[], int *fds, int *efd, int *opid)
{
char tmp[256];
int pid, toast[2], fromast[2], audio[2], res;
struct stat st;
if (!strncasecmp(script, "agi://", 6))
return launch_netscript(script, argv, fds, efd, opid);
if (!strncasecmp(script, "agi:async", sizeof("agi:async")-1))
if (!strncasecmp(script, "agi://", 6)) {
return (efd == NULL) ? launch_netscript(script, argv, fds) : AGI_RESULT_FAILURE;
}
if (!strncasecmp(script, "hagi://", 7)) {
return (efd == NULL) ? launch_ha_netscript(script, argv, fds) : AGI_RESULT_FAILURE;
}
if (!strncasecmp(script, "agi:async", sizeof("agi:async") - 1)) {
return launch_asyncagi(chan, argv, efd);
}
if (script[0] != '/') {
snprintf(tmp, sizeof(tmp), "%s/%s", ast_config_AST_AGI_DIR, script);
@ -3590,7 +3660,7 @@ static int agi_exec_full(struct ast_channel *chan, const char *data, int enhance
{
enum agi_result res;
char *buf;
int fds[2], efd = -1, pid;
int fds[2], efd = -1, pid = -1;
AST_DECLARE_APP_ARGS(args,
AST_APP_ARG(arg)[MAX_ARGS];
);

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