Updated demo code to show handling of different packet types

alxhoff · May 9, 2023 · c04163b · c04163b
1 parent 753d9ec
commit c04163b
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Showing 2 changed files with 55 additions and 7 deletions.
diff --git a/include/UDP_data.h b/include/UDP_data.h
@@ -1,7 +1,20 @@
 #ifndef __UDP_DATA_H__
 #define __UDP_DATA_H__
 
+#define PACKET_TYPE_CONFIG 0x0
+#define PACKET_TYPE_DATA 0x1
+
+// The packed attribute here is important if you want to parse
+// your structs manually, ie. struct pointer + so many bytes.
+// Packing the structs will ensure the compiler doesn't add in
+// padding for memory allignment.
+struct __attribute__((packed)) config_packet {
+    char packet_type;
+    char config_byte;
+};
+
 struct __attribute__((packed)) data_packet {
+    char packet_type;
     int my_int;
     char my_string[20];
 };

diff --git a/src/main.c b/src/main.c
@@ -236,7 +236,6 @@ void vDrawIP(unsigned char IP[4], unsigned int port)
     sprintf(buff, "%u", port);
     gfxDrawCenteredText(buff, PORT_X, OCTET_Y, Black);
 
-
     // sprintf(buff, "   ip         port");
     // gfxDrawCenteredText(buff, SCREEN_WIDTH / 2, OCTET_Y + 20, Black);
 }
@@ -394,7 +393,15 @@ void vSendTask(void *pvParameters)
         xSemaphoreGive(ip_and_port.lock);
     }
 
-    struct data_packet my_packet = {.my_int = 555, .my_string = "Hello via UDP"};
+    struct config_packet my_config_packet = { .packet_type =
+            PACKET_TYPE_CONFIG,
+            .config_byte = 0b10101010
+    };
+
+    struct data_packet my_data_packet = { .packet_type = PACKET_TYPE_DATA,
+               .my_int = 555,
+               .my_string = "Hello via UDP"
+    };
 
     while (1) {
         gfxEventFetchEvents(
@@ -407,17 +414,46 @@ void vSendTask(void *pvParameters)
 
         gfxDrawUpdateScreen(); // Refresh the screen to draw string
 
-        aIOSocketPut(UDP, addr, port, (char *)&my_packet, sizeof(struct data_packet));
+        printf("Sending config packet...");
+        aIOSocketPut(UDP, addr, port, (char *)&my_config_packet,
+                     sizeof(struct config_packet));
+        printf("Packet sent\n");
+
+        vTaskDelay(1000);
+
+        printf("Sending data packet...");
+        aIOSocketPut(UDP, addr, port, (char *)&my_data_packet,
+                     sizeof(struct data_packet));
+        printf("Packet sent\n");
 
         vTaskDelay(1000);
     }
 }
 
 void UDPHandler(size_t read_size, char *buffer, void *args)
 {
-    struct data_packet *recv_packet = (struct data_packet *)buffer;
+    printf("Packet received\n");
+
+    // Get first byte to check packet type
+    char packet_type = *buffer;
 
-    printf("Recv int: %d and string: %s\n", recv_packet->my_int, recv_packet->my_string);
+    // Handle packet depending on type
+    switch (packet_type) {
+        case PACKET_TYPE_CONFIG: {
+            struct config_packet *config_packet =
+                (struct config_packet *)buffer;
+
+            printf("Recv config byte: %x\n", config_packet->config_byte);
+        } break;
+        case PACKET_TYPE_DATA: {
+            struct data_packet *data_packet = (struct data_packet *)buffer;
+
+            printf("Recv int: %d and string: %s\n", data_packet->my_int,
+                   data_packet->my_string);
+        } break;
+        default:
+            break;
+    }
 }
 
 void vRecvTask(void *pvParameters)
@@ -429,8 +465,7 @@ void vRecvTask(void *pvParameters)
         xSemaphoreGive(ip_and_port.lock);
     }
 
-    aIOOpenUDPSocket(NULL, port, UDP_BUFFER_SIZE,
-                     UDPHandler, NULL);
+    aIOOpenUDPSocket(NULL, port, UDP_BUFFER_SIZE, UDPHandler, NULL);
 
     gfxDrawBindThread();