Peter M. Groen / libmodbus

Commit 7ecfd4110a6b169bd96629f81dc43f0a352a0cfa

Authored by Alex Stapleton
Committed by Stéphane Raimbault
1 parent 98b7a6a1

Added slave ID check for response messages

Inline Side-by-side
Showing 2 changed files with 9 additions and 0 deletions
src/modbus.c
  View file @7ecfd41
@@ -80,6 +80,8 @@ const char *modbus_strerror(int errnum) { @@ -80,6 +80,8 @@ const char *modbus_strerror(int errnum) {
80 return "Invalid exception code"; 80 return "Invalid exception code";
81 case EMBMDATA: 81 case EMBMDATA:
82 return "Too many data"; 82 return "Too many data";
  83 + case EMBBADSLAVE:
  84 + return "Response not from requested slave";
83 default: 85 default:
84 return strerror(errnum); 86 return strerror(errnum);
85 } 87 }
@@ -492,6 +494,12 @@ static int check_confirmation(modbus_t *ctx, uint8_t *req, @@ -492,6 +494,12 @@ static int check_confirmation(modbus_t *ctx, uint8_t *req,
492 } 494 }
493 } 495 }
494 496
  497 + /* Check responding slave is the slave we requested */
  498 + if(req[0] != 0 && rsp[0] != req[0]) {
  499 + errno = EMBBADSLAVE;
  500 + return -1;
  501 + }
  502 +
495 rsp_length_computed = compute_response_length_from_request(ctx, req); 503 rsp_length_computed = compute_response_length_from_request(ctx, req);
496 504
497 /* Check length */ 505 /* Check length */
src/modbus.h
  View file @7ecfd41
@@ -117,6 +117,7 @@ enum { @@ -117,6 +117,7 @@ enum {
117 #define EMBBADEXC (EMBXGTAR + 3) 117 #define EMBBADEXC (EMBXGTAR + 3)
118 #define EMBUNKEXC (EMBXGTAR + 4) 118 #define EMBUNKEXC (EMBXGTAR + 4)
119 #define EMBMDATA (EMBXGTAR + 5) 119 #define EMBMDATA (EMBXGTAR + 5)
  120 +#define EMBBADSLAVE (EMBXGTAR + 6)
120 121
121 extern const unsigned int libmodbus_version_major; 122 extern const unsigned int libmodbus_version_major;
122 extern const unsigned int libmodbus_version_minor; 123 extern const unsigned int libmodbus_version_minor;