udp: Make the SNMP code asynchronous
Do not block the application when doing a SNMP request. Work
with the results coming back from the callback. Right now a
link can only be taken down and up.
diff --git a/include/bsc_data.h b/include/bsc_data.h
index 3311d53..1092d6e 100644
--- a/include/bsc_data.h
+++ b/include/bsc_data.h
@@ -141,7 +141,7 @@
unsigned int sls_for_src_ref(struct sccp_source_reference *ref);
/* udp init */
-int link_global_init(struct mtp_udp_data *data, int src_port);
+int link_global_init(struct mtp_udp_data *data, char *dest_ip, int src_port);
int link_udp_init(struct mtp_udp_link *data, const char *dest_ip, int port);
int link_init(struct bsc_data *bsc);
int link_shutdown_all(struct mtp_link_set *);
diff --git a/include/snmp_mtp.h b/include/snmp_mtp.h
index 045e90f..8c15df7 100644
--- a/include/snmp_mtp.h
+++ b/include/snmp_mtp.h
@@ -26,6 +26,27 @@
struct snmp_mtp_session {
netsnmp_session session, *ss;
+ void *data;
+
+ /*
+ * The callbacks will be called multiple times. Even if
+ * we only toggle one object. Remember which request we
+ * are handling here and then we will claim success on the
+ * first of a series of PDUs. This is the easies to manage
+ * and if a link fails to come up the SLTM will catch it.
+ */
+ int last_up_req;
+ int last_do_req;
+};
+
+enum {
+ SNMP_LINK_UP,
+ SNMP_LINK_DOWN,
+};
+
+enum {
+ SNMP_STATUS_OK,
+ SNMP_STATUS_TIMEOUT,
};
struct snmp_mtp_session *snmp_mtp_session_create(char *host);
@@ -33,4 +54,7 @@
void snmp_mtp_activate(struct snmp_mtp_session *, int link_id);
void snmp_mtp_poll();
+/* to be implemented by the handler */
+void snmp_mtp_callback(struct snmp_mtp_session *, int area, int res, int link_id);
+
#endif
diff --git a/src/link_udp.c b/src/link_udp.c
index fd6b1f9..f7c6703 100644
--- a/src/link_udp.c
+++ b/src/link_udp.c
@@ -157,7 +157,6 @@
struct mtp_udp_link *link = (struct mtp_udp_link *) _data;
snmp_mtp_activate(link->data->session, link->link_index);
- mtp_link_up(&link->base);
}
static int udp_link_reset(struct mtp_link *link)
@@ -166,16 +165,7 @@
ulnk = (struct mtp_udp_link *) link;
- LOGP(DINP, LOGL_NOTICE, "Will restart SLTM transmission in %d seconds.\n",
- ulnk->reset_timeout);
-
snmp_mtp_deactivate(ulnk->data->session, ulnk->link_index);
- mtp_link_down(link);
-
- /* restart the link in 90 seconds... to force a timeout on the BSC */
- link->link_activate.cb = do_start;
- link->link_activate.data = link;
- bsc_schedule_timer(&link->link_activate, ulnk->reset_timeout, 0);
return 0;
}
@@ -239,12 +229,18 @@
bsc_schedule_timer(&data->snmp_poll, 0, 5000);
}
-int link_global_init(struct mtp_udp_data *data, int src_port)
+int link_global_init(struct mtp_udp_data *data, char *udp_ip, int src_port)
{
struct sockaddr_in addr;
int fd;
int on;
+ /* setup SNMP first, it is blocking */
+ data->session = snmp_mtp_session_create(udp_ip);
+ if (!data->session)
+ return -1;
+ data->session->data = data;
+
INIT_LLIST_HEAD(&data->links);
write_queue_init(&data->write_queue, 100);
@@ -287,3 +283,45 @@
return 0;
}
+
+void snmp_mtp_callback(struct snmp_mtp_session *session,
+ int area, int res, int link_id)
+{
+ struct mtp_udp_data *data;
+ struct mtp_udp_link *ulink;
+ struct mtp_link *link;
+
+ data = session->data;
+ ulink = find_link(data, link_id);
+ if (!ulink)
+ return LOGP(DINP, LOGL_ERROR, "Failed to find link %d\n", link_id);
+
+ link = &ulink->base;
+
+ if (res == SNMP_STATUS_TIMEOUT) {
+ LOGP(DINP, LOGL_ERROR, "Failed to restart link: %d\n", link_id);
+ udp_link_reset(link);
+ return;
+ }
+
+ switch (area) {
+ case SNMP_LINK_UP:
+ mtp_link_up(link);
+ break;
+ case SNMP_LINK_DOWN:
+ mtp_link_down(link);
+
+ /*
+ * restart the link in 90 seconds...
+ * to force a timeout on the BSC
+ */
+ link->link_activate.cb = do_start;
+ link->link_activate.data = link;
+ bsc_schedule_timer(&link->link_activate, ulink->reset_timeout, 0);
+ LOGP(DINP, LOGL_NOTICE,
+ "Will restart SLTM transmission in %d seconds.\n", ulink->reset_timeout);
+ break;
+ default:
+ LOGP(DINP, LOGL_ERROR, "Unknown event %d\n", area);
+ }
+}
diff --git a/src/links.c b/src/links.c
index bf282b6..4342447 100644
--- a/src/links.c
+++ b/src/links.c
@@ -126,12 +126,7 @@
LOGP(DINP, LOGL_NOTICE, "Using UDP MTP mode.\n");
- /* setup SNMP first, it is blocking */
- bsc->udp_data.session = snmp_mtp_session_create(bsc->udp_ip);
- if (!bsc->udp_data.session)
- return -1;
-
- if (link_global_init(&bsc->udp_data, bsc->src_port) != 0)
+ if (link_global_init(&bsc->udp_data, bsc->udp_ip, bsc->src_port) != 0)
return -1;
/* now connect to the transport */
diff --git a/src/snmp_mtp.c b/src/snmp_mtp.c
index ec4d892..2cdf323 100644
--- a/src/snmp_mtp.c
+++ b/src/snmp_mtp.c
@@ -41,39 +41,83 @@
}
}
-static void send_pdu(netsnmp_session *ss, netsnmp_pdu *pdu)
+static int link_up_cb(int op, netsnmp_session *ss,
+ int reqid, netsnmp_pdu *pdu, void *data)
+{
+ struct snmp_mtp_session *mtp = ss->myvoid;
+ int link_index = (int) data;
+
+ if (mtp->last_up_req != reqid)
+ return 0;
+
+ mtp->last_up_req = 0;
+ snmp_mtp_callback(mtp, SNMP_LINK_UP,
+ op == STAT_TIMEOUT ? SNMP_STATUS_TIMEOUT : SNMP_STATUS_OK,
+ link_index);
+ return 0;
+}
+
+static int link_down_cb(int op, netsnmp_session *ss,
+ int reqid, netsnmp_pdu *pdu, void *data)
+{
+ struct snmp_mtp_session *mtp = ss->myvoid;
+ int link_index = (int) data;
+
+ if (mtp->last_do_req != reqid)
+ return 0;
+
+ mtp->last_do_req = 0;
+ snmp_mtp_callback(mtp, SNMP_LINK_DOWN,
+ op == STAT_TIMEOUT ? SNMP_STATUS_TIMEOUT : SNMP_STATUS_OK,
+ link_index);
+ return 0;
+}
+
+static int send_pdu(netsnmp_session *ss, netsnmp_pdu *pdu, int kind, int link_id)
{
int status;
- netsnmp_pdu *response;
+ netsnmp_callback cb;
- status = snmp_synch_response(ss, pdu, &response);
- if (status == STAT_ERROR) {
- snmp_sess_perror("set failed", ss);
- } else if (status == STAT_TIMEOUT) {
- fprintf(stderr, "Timeout for SNMP.\n");
+ cb = kind == SNMP_LINK_UP ? link_up_cb : link_down_cb;
+
+ status = snmp_async_send(ss, pdu, cb, (void *) link_id);
+ if (status == 0) {
+ snmp_log(LOG_ERR, "Failed to send async request.\n");
+ snmp_free_pdu(pdu);
}
- if (response)
- snmp_free_pdu(response);
+ return status;
}
static void snmp_mtp_start_c7_datalink(struct snmp_mtp_session *session, int link_id)
{
+ int status;
netsnmp_pdu *pdu;
pdu = snmp_pdu_create(SNMP_MSG_SET);
add_pdu_var(pdu, "PTI-NexusWareC7-MIB::nwc7DatalinkCommand", link_id, "nwc7DatalinkCmdPowerOn");
add_pdu_var(pdu, "PTI-NexusWareC7-MIB::nwc7Mtp2Active", link_id, "true");
- send_pdu(session->ss, pdu);
+ status = send_pdu(session->ss, pdu, SNMP_LINK_UP, link_id);
+
+ if (status == 0)
+ snmp_mtp_callback(session, SNMP_LINK_UP, SNMP_STATUS_TIMEOUT, link_id);
+ else
+ session->last_up_req = status;
+
}
static void snmp_mtp_stop_c7_datalink(struct snmp_mtp_session *session, int link_id)
{
+ int status;
netsnmp_pdu *pdu;
pdu = snmp_pdu_create(SNMP_MSG_SET);
add_pdu_var(pdu, "PTI-NexusWareC7-MIB::nwc7Mtp2Active", link_id, "false");
- send_pdu(session->ss, pdu);
+ status = send_pdu(session->ss, pdu, SNMP_LINK_DOWN, link_id);
+ if (status == 0)
+ snmp_mtp_callback(session, SNMP_LINK_DOWN, SNMP_STATUS_TIMEOUT, link_id);
+ else
+ session->last_do_req = status;
}
struct snmp_mtp_session *snmp_mtp_session_create(char *host)
@@ -88,6 +132,7 @@
session->session.version = SNMP_VERSION_1;
session->session.community = (unsigned char *) "private";
session->session.community_len = strlen((const char *) session->session.community);
+ session->session.myvoid = session;
session->ss = snmp_open(&session->session);
if (!session->ss) {