firmware: decoding BER...

uhppoted · Aug 16, 2024 · f99d53e · f99d53e
1 parent 4bfc44e
commit f99d53e
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Showing 5 changed files with 64 additions and 18 deletions.
diff --git a/Rev.0/emulator/encoding/bisync/bisync.go b/Rev.0/emulator/encoding/bisync/bisync.go
@@ -173,12 +173,10 @@ func (codec *Bisync) decode(msg []uint8, f callback) error {
 				codec.reset()
 
 			case STX:
-				println("STX")
 				codec.SOH = false
 				codec.STX = true
 
 			case ETX:
-				println("ETX")
 				codec.SOH = false
 				codec.STX = false
 

diff --git a/Rev.0/emulator/ssmp/ssmp.go b/Rev.0/emulator/ssmp/ssmp.go
@@ -318,14 +318,16 @@ func listen(USB string, tx chan []byte, rx chan []byte, pipe chan []byte, errors
 		for {
 			select {
 			case msg := <-pipe:
-				// if len(msg) > 20 {
-				// 	debugf("read  (%v bytes) [%v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v ...]",
-				// 		len(msg),
-				// 		msg[0], msg[1], msg[2], msg[3], msg[4], msg[5], msg[6], msg[7], msg[8], msg[9],
-				// 		msg[10], msg[11], msg[12], msg[13], msg[14], msg[15], msg[16], msg[17], msg[18], msg[19])
-				// } else {
-				// 	debugf("read  (%v bytes) %v", len(msg), msg)
-				// }
+				if msg[0] != 22 {
+					debugf("read  (%v bytes) %v", len(msg), string(msg))
+				} else if len(msg) > 20 {
+					debugf("read  (%v bytes) [%v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v ...]",
+						len(msg),
+						msg[0], msg[1], msg[2], msg[3], msg[4], msg[5], msg[6], msg[7], msg[8], msg[9],
+						msg[10], msg[11], msg[12], msg[13], msg[14], msg[15], msg[16], msg[17], msg[18], msg[19])
+				} else {
+					debugf("read  (%v bytes) %v", len(msg), msg)
+				}
 
 				select {
 				case rx <- msg:
@@ -339,13 +341,13 @@ func listen(USB string, tx chan []byte, rx chan []byte, pipe chan []byte, errors
 					warnf("write error (%v)", err)
 				} else if N != len(msg) {
 					warnf("write error (%v)", fmt.Errorf("sent %v bytes of %v)", N, len(msg)))
-					// } else if len(msg) > 20 {
-					// 	debugf("write (%v bytes) [%v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v ...]",
-					// 		N,
-					// 		msg[0], msg[1], msg[2], msg[3], msg[4], msg[5], msg[6], msg[7], msg[8], msg[9],
-					// 		msg[10], msg[11], msg[12], msg[13], msg[14], msg[15], msg[16], msg[17], msg[18], msg[19])
-					// } else {
-					// 	debugf("write (%v bytes) %v", N, msg)
+				} else if len(msg) > 20 {
+					debugf("write (%v bytes) [%v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v %v ...]",
+						N,
+						msg[0], msg[1], msg[2], msg[3], msg[4], msg[5], msg[6], msg[7], msg[8], msg[9],
+						msg[10], msg[11], msg[12], msg[13], msg[14], msg[15], msg[16], msg[17], msg[18], msg[19])
+				} else {
+					debugf("write (%v bytes) %v", N, msg)
 				}
 
 			case <-idle:

diff --git a/Rev.0/firmware/lib/include/encoding/encoding.h b/Rev.0/firmware/lib/include/encoding/encoding.h
@@ -15,10 +15,12 @@ typedef struct packet {
     PACKET tag;
     union {
         struct {
+            uint8_t version;
             uint32_t request_id;
         } get;
 
         struct {
+            uint8_t version;
             uint32_t request_id;
         } get_response;
     };

diff --git a/Rev.0/firmware/lib/src/encoding/BER/BER.c b/Rev.0/firmware/lib/src/encoding/BER/BER.c
@@ -1,8 +1,11 @@
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include <encoding/BER/BER.h>
 
+void unpack_sequence(const uint8_t *message, int N, int *ix);
+
 // clang-format off
 const uint8_t RESPONSE[] = {
     48,  41,  2,   1,   0,  4,   6,  112, 
@@ -28,9 +31,46 @@ struct packet BER_decode(const uint8_t *message, int N) {
     packet p = {
         .tag = PACKET_GET,
         .get = {
+            .version = 0,
             .request_id = 1,
         },
     };
 
+    // ... unpack message
+    int ix = 0;
+
+    if (ix < N) {
+        uint8_t tag = message[ix++];
+
+        switch (tag) {
+        case 0x30:
+            unpack_sequence(message, N, &ix);
+            break;
+        }
+    }
+
+    fflush(stdout);
+
     return p;
 }
+
+void unpack_sequence(const uint8_t *message, int N, int *ix) {
+    // ... length
+    uint64_t length = 0;
+    if (*ix < N) {
+        uint8_t b = message[*ix++];
+
+        if (b & 0x80 == 0x80) {
+            length = (uint64_t)(b & 0x7f);
+        } else {
+            int len = b & 0x7f;
+            for (int i = 0; i < len && *ix < N; i++) {
+                length <<= 8;
+                length += (uint64_t)(message[*ix++]);
+            }
+        }
+    }
+
+    printf("<<sequence %llu>>   ", length);
+    fflush(stdout);
+}
diff --git a/TODO.md b/TODO.md
@@ -37,8 +37,12 @@
          - [x] return SnmpGetResponse
          - [x] encode::DLE 
          - [x] require STX-ETX framing
-         - [x] BER
          - [ ] CRC
+         - [ ] BER
+               - https://www.oss.com/asn1/resources/asn1-made-simple/asn1-quick-reference/basic-encoding-rules.html
+```
+2024-08-16 15:33:33 DEBUG  SSMP             write (58 bytes) [22 22 2 48 37 16 2 16 1 0 4 16 6 112 117 98 108 105 99 160 ...]
+```
    - [x] SSMP idle - revert to MODE_UNKNOWN
    - [ ] Enable FIFO
    - [ ] pico: txrx/uart conflict