xnu-3789.1.32.tar.gz

[apple/xnu.git] / osfmk / kdp / kdp_serial.c

diff --git a/osfmk/kdp/kdp_serial.c b/osfmk/kdp/kdp_serial.c
index bc8f1369be53edd32e209595d2cd0e4b86612303..0bf85a9b3112f5b0c9e35fd07c486d8dd0a7cdb3 100644 (file)
--- a/osfmk/kdp/kdp_serial.c
+++ b/osfmk/kdp/kdp_serial.c
@@ -26,6 +26,9 @@
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 #include "kdp_serial.h"
+#include <libkern/zlib.h>
+#include <stdint.h>
+#include <stdbool.h>
 
 #define SKDP_START_CHAR 0xFA
 #define SKDP_END_CHAR 0xFB
@@ -34,26 +37,47 @@
 static enum {DS_WAITSTART, DS_READING, DS_ESCAPED} dsState;
 static unsigned char dsBuffer[1518];
 static int dsPos;
+static uint32_t dsCRC;
+static bool dsHaveCRC;
+
+
+static void kdp_serial_out(unsigned char byte, void (*outFunc)(char))
+{
+       //need to escape '\n' because the kernel serial output turns it into a cr/lf
+       if(byte == SKDP_START_CHAR || byte == SKDP_END_CHAR || byte == SKDP_ESC_CHAR || byte == '\n')
+       {
+               outFunc(SKDP_ESC_CHAR);
+               byte = ~byte;
+       }
+       outFunc(byte);
+}
 
 void kdp_serialize_packet(unsigned char *packet, unsigned int len, void (*outFunc)(char))
 {
-       unsigned int index;
+       unsigned int  index;
+       unsigned char byte;
+       uint32_t      crc;
+
+       // insert the CRC between back to back STARTs which is compatible with old clients
+       crc = (uint32_t) z_crc32(0, packet, len);
+       outFunc(SKDP_START_CHAR);
+       kdp_serial_out((crc >> 0),  outFunc);
+       kdp_serial_out((crc >> 8),  outFunc);
+       kdp_serial_out((crc >> 16), outFunc);
+       kdp_serial_out((crc >> 24), outFunc);
+
        outFunc(SKDP_START_CHAR);
        for (index = 0; index < len; index++) {
-               unsigned char byte = *packet++;
-               //need to escape '\n' because the kernel serial output turns it into a cr/lf
-               if(byte == SKDP_START_CHAR || byte == SKDP_END_CHAR || byte == SKDP_ESC_CHAR || byte == '\n')
-               {
-                       outFunc(SKDP_ESC_CHAR);
-                       byte = ~byte;
-               }
-               outFunc(byte);
+               byte = *packet++;
+               kdp_serial_out(byte, outFunc);
        }
        outFunc(SKDP_END_CHAR);
 }
 
 unsigned char *kdp_unserialize_packet(unsigned char byte, unsigned int *len)
 {
+       uint32_t crc;
+
        switch(dsState)
        {
                case DS_WAITSTART:
@@ -63,6 +87,7 @@ unsigned char *kdp_unserialize_packet(unsigned char byte, unsigned int *len)
                                dsState = DS_READING;
                                dsPos = 0;
                                *len = SERIALIZE_READING;
+                               dsHaveCRC = false;
                                return 0;
                        }
                        *len = SERIALIZE_WAIT_START;
@@ -76,7 +101,12 @@ unsigned char *kdp_unserialize_packet(unsigned char byte, unsigned int *len)
                        }
                        if(byte == SKDP_START_CHAR)
                        {
-//                             printf("unexpected start char, resetting\n");
+                               if (dsPos >= 4) 
+                               {
+                                       dsHaveCRC = true;
+                                       dsCRC = dsBuffer[0] | (dsBuffer[1] << 8) | (dsBuffer[2] << 16) | (dsBuffer[3] << 24);
+                               }
+                               //else                          printf("unexpected start char, resetting\n");
                                dsPos = 0;
                                *len = SERIALIZE_READING;
                                return 0;
@@ -84,6 +114,17 @@ unsigned char *kdp_unserialize_packet(unsigned char byte, unsigned int *len)
                        if(byte == SKDP_END_CHAR)
                        {
                                dsState = DS_WAITSTART;
+                               if (dsHaveCRC)
+                               {
+                                       crc = (uint32_t) z_crc32(0, &dsBuffer[0], dsPos);
+                                       if (crc != dsCRC)
+                                       {
+//                                             printf("bad packet crc 0x%x != 0x%x\n", crc, dsCRC);
+                                               dsPos = 0;
+                                               *len = SERIALIZE_WAIT_START;
+                                               return 0;
+                                       }
+                               }
                                *len = dsPos;
                                dsPos = 0;
                                return dsBuffer;