SNMP: Add Uptime OID, so make it easier to catch modem reboots.

Makefile: update build arguments to remove one warning

Makefile

@@ -362,7 +362,7 @@ C_FLAGS += -DARM_MATH_CM4
 C_FLAGS += -include
 C_FLAGS += mbed_config.h
 
-CXX_FLAGS += -std=gnu++98
+CXX_FLAGS += -std=gnu++11
 CXX_FLAGS += -fno-rtti
 CXX_FLAGS += -Wvla
 CXX_FLAGS += -D__MBED__=1

source/SNMP.cpp

@@ -33,8 +33,8 @@ dataEntryType snmpData[] =
         // SysDescr Entry
         {8, {0x2b, 6, 1, 2, 1, 1, 1, 0}, ASN_OCTETSTRING, 6, {"NPR-70"}, NULL, NULL},
 
-        // SysUptime Entry (not working yet)
-        // {8, {0x2b, 6, 1, 2, 1, 1, 3, 0}, ASN_TIMETICKS, 0, { .intval = 0x2345 }, NULL, NULL},
+        // SysUptime Entry
+        {8, {0x2b, 6, 1, 2, 1, 1, 3, 0}, ASN_TIMETICKS, 0, {}, snmpGetUptime, NULL},
 
         // 1.3.6.1.4.1.54539 (Wizkers)
         //               .100 (NPR-70)
@@ -78,6 +78,12 @@ void hexdump(uint8_t *buffer, uint16_t len)
     printf("\r\n");
 }
 
+void snmpGetUptime(void *ptr, uint8_t *len) {
+    time_t seconds = time(NULL);
+    *(uint32_t *)ptr = (uint32_t)(seconds*100); // Time in 100th of a second
+    *len = 4; 
+}
+
 void snmpGetVar(void *ptr, uint8_t *len,  const uint32_t var) {
 	*(uint32_t *)ptr = (uint32_t)(var);
 	*len = 4;
@@ -625,6 +631,13 @@ int8_t parse_snmp()
     return 0;
 }
 
+/**
+ * Initialize the SNMP stack
+ */
+void snmp_init() {
+    set_time(0);
+}
+
 /**
  * Called at regular intervals and acts if the SNMP socket contains data
  */

source/SNMP.h

@@ -121,8 +121,9 @@ typedef struct {
  * Very simplistic implementation of a SNMP agent that will return basic stats
  * on the modem. Read only, community is 'public'
  */
-void snmp_init(uint8_t snmp_socket);
+void snmp_init();
 void snmp_loop(W5500_chip* W5500);
+void snmpGetUptime(void *ptr, uint8_t *len);
 void snmpGetTemp(void *ptr, uint8_t *len); // Get system temperature callback
 void snmpGetLinkStatus(void *ptr, uint8_t *len);
 void snmpGetLinkDistance(void *ptr, uint8_t *len);

source/main.cpp

@@ -94,6 +94,8 @@ int main()
 	G_PTT_PA_pin = &PTT_PA_pin;
 
 	reset_DHCP_table(LAN_conf_p);
+
+	snmp_init();
 
     spi_2.format(8,0);
 	spi_1.format(8,0);