SICS-128: The reactor status protocol now just searches for a line containing "Power:" and returns it as the reactor status.

site_ansto/hardsup/aqp_opalstatus.c

@@ -2,7 +2,36 @@
  * @brief
  * Implements a simple protocol to GET reactor status using an HTTP/1.1 GET.
  * It sets the UserAgent as SICS to avoid re-directs because we don't handle them.
- * If the HTTP status is not OK then it returns the status in the data buffer.
+ * If the HTTP status is not OK or if the driver fails to find a line that
+ * contains the "Power:" field then it returns the unprocessed reply
+ * characters in the data buffer.
+ *
+ * The reply is expected to have a form similar to the following,
+ *   HTTP/1.1 200 OK
+ *   Date: Thu, 26 Feb 2015 01:27:30 GMT
+ *   Server: Oracle-Application-Server-10g/10.1.3.5.0 Oracle-HTTP-Server
+ *   Content-Location: /reactor.jsp
+ *   Content-Type: text/plain; charset=UTF-8
+ *   Set-Cookie: JSESSIONID=74646fa7cf3cdf53a371694a33ab760cd649631d758f416d916c6d1b496a477b.e34Pc3qNbh4RaO0Ma3yMbxaRaN0Ke0; path=/Bragg
+ *   Connection: close
+ *   Transfer-Encoding: chunked
+ *   
+ *   4f
+ *   Power: 19.381588; CNS Out: 25.76; TG123: 1; CG123: 1; TG4: Open; HB1: 0; HB2: 1
+ *   
+ *   0
+ *
+ * It should have no more than 512 characters excluding the HTTP OK status.
+ * Each line is expected to be terminated with a \r\n.
+ * The reply is expected to begin with "HTTP/1.1 200 OK"
+ * A line is identified as the status message if and only if it includes
+ * "Power:" regardless of case.
+ * The reply is expected to end with 0\r\n\r\n
+ *
+ * Processing lines is simplified by discarding \r characters and then just
+ * checking for \n.
+ * NOTE: This implies that \n should not be used in the status line as a
+ * delimiter.
  */
 #include "../made_config.h"
 #include <sics.h>
@@ -16,73 +45,78 @@
 #define USERAGENT "User-Agent: SICS\r\n"
 #endif
 #define HOST "Host: neutron.ansto.gov.au\r\n"
+/* Assume that the first field in the reactor status starts with "Power" */
+#define PWR_FLD "Power"
+#define PWR_FLD_LEN 5
 
-enum replystates {START, HEADER, CHKHEADEREND, MSG};
+enum replystates {START, CHK_PWR_FLD, MSG, END_MSG, DRAIN_REPLY};
 static pAsyncProtocol OPAL_Protocol = NULL;
 
-/* The header and message are followed by the character sequences given below,
+/* The message is assumed to start with "Power:" and terminated with crlf.
- * HEADER cr lf cr lf <msg len> cr lf
- * MESSAGE cr lf 0x30 cr lf cr lf
- * So we assume that the header is terminated by two consecutive crlf char
- * pairs which are eventually followed by another crlf
- * The message is assumed to be terminated by a crlf pair eventually followed
  * by two more crlf pairs of characters
- * Processing is simplified by discarding cr chars and counting lf chars */
+ * Processing of line terminators is simplified by discarding cr chars */
 static int OPAL_Rx(pAsyncProtocol p, pAsyncTxn txn, int ch) {
+  char *fldptr;
   int ret = 1;
-  static int nlctr = 0;
+  static int char_ctr = 0, newline_ctr = 0;
   static enum replystates state = START;
 
+  if (char_ctr++ >= txn->inp_len) {
+    char_ctr = 0;
+    newline_ctr = 0;
+    state = START;
+    return AQU_POP_CMD;
+  }
   if (ch == '\r') {
     return ret;
   }
   switch (state) {
     case START:
       if (ch == '\n') {
-        /* check HTTP status */
+        /* check HTTP status is OK before proceeding */
         if ( strncmp(txn->inp_buf, HTTP_OK, strlen(HTTP_OK) ) == 0 ) {
           txn->inp_idx = 0;
-          nlctr = 0;
+          state = CHK_PWR_FLD;
-          state = HEADER;
         } else
           ret = AQU_POP_CMD;
-      } else if (txn->inp_idx < txn->inp_len)
+      } else
         txn->inp_buf[txn->inp_idx++] = ch;
-      else
-        ret = AQU_POP_CMD;
       break;
-    case HEADER:
+    case CHK_PWR_FLD:
       if (ch == '\n') {
-        nlctr++;
-        state = CHKHEADEREND;
-      }
-      break;
-    case CHKHEADEREND:
-      if (nlctr == 1 && ch == '\n')
-        nlctr++;
-      else if (nlctr == 1 && ch != '\n') {
         txn->inp_idx = 0;
-        nlctr = 0;
+      } else if (ch == ':') {
-        state = HEADER;
+        if ( txn->inp_idx >= PWR_FLD_LEN ) {
-      } else if (nlctr == 2 && ch == '\n') {
+          /* Check for "Power" field anywhere in status line */
-        txn->inp_idx = 0;
+          fldptr = &txn->inp_buf[txn->inp_idx - PWR_FLD_LEN];
-        nlctr = 0;
+          if ( strncasecmp(fldptr, PWR_FLD, PWR_FLD_LEN) == 0 ) {
-        state = MSG;
+            state = MSG;
+          }
+        }
       }
+      txn->inp_buf[txn->inp_idx++] = ch;
       break;
     case MSG:
-      if (txn->inp_idx >= txn->inp_len)
+      if (ch == '\n') {
-        ret = AQU_POP_CMD;
+        state = END_MSG;
-      if (nlctr == 0 && ch != '\n')
+      } else {
         txn->inp_buf[txn->inp_idx++] = ch;
-      else if (nlctr == 2 && ch == '\n')
+      }
+      break;
+    case END_MSG:
+      if (ch == '0') {
+        state = DRAIN_REPLY;
+      }
+      break;
+    case DRAIN_REPLY:
+      newline_ctr++;
+      if (newline_ctr >= 2)
         ret = AQU_POP_CMD;
-      else
-        nlctr++;
       break;
   }
   if (ret == AQU_POP_CMD) {
-    nlctr = 0;
+    char_ctr = 0;
+    newline_ctr = 0;
     state = START;
   }
   return ret;
@@ -116,7 +150,7 @@ static int OPAL_PrepareTxn(pAsyncProtocol p, pAsyncTxn txn, const char* cmd, int
   if (txn->inp_buf != NULL) {
     free(txn->inp_buf);
   }
-  txn->inp_len = rsp_len;
+  txn->inp_len = 512;
   txn->inp_idx = 0;
   txn->txn_state = 0;
   txn->txn_status = 0;