serial-parsers: don't echo-remove strange call start/end URCs

Some Sierra devices omit the leading <CR> from call start/end URCs
like NO CARRIER and CONNECT, which caused the echo-removal code to
remove from the response buffer because the leading <CR><LF> did
not exist. That can break call control and hangup handling on
those devices.

Signed-off-by: Dan Williams <dan@ioncontrol.co>

src/mm-modem-helpers.c

@@ -487,8 +487,12 @@ mm_call_end_regex_get (void)
 {
     /* Example:
      * <CR><LF>NO ANSWER<CR><LF>
+     * <LF>NO CARRIER<CR><LF>
+     * <CR><LF>BUSY<CR><LF>
+     *
+     * Some Sierra devices omit the leading <CR> for in-call responses.
      */
-    return g_regex_new ("\\r\\n(NO CARRIER)|(BUSY)|(NO ANSWER)|(NO DIALTONE)\\r\\n",
+    return g_regex_new ("(\\r)?\\n(NO CARRIER)|(BUSY)|(NO ANSWER)|(NO DIALTONE)\\r\\n",
                         G_REGEX_DOLLAR_ENDONLY | G_REGEX_RAW | G_REGEX_OPTIMIZE,
                         0,
                         NULL);

src/mm-serial-parsers.c

@@ -17,8 +17,11 @@
 #include <string.h>
 #include <stdlib.h>
 
+#define _LIBMM_INSIDE_MM
+
 #include "mm-error-helpers.h"
 #include "mm-serial-parsers.h"
+#include "mm-modem-helpers.h"
 #include "mm-log-object.h"
 
 /* Clean up the response by removing control characters like <CR><LF> etc */
@@ -92,7 +95,8 @@ typedef struct {
     GRegex *regex_cms_error_str;
     GRegex *regex_ezx_error;
     GRegex *regex_unknown_error;
-    GRegex *regex_connect_failed;
+    GRegex *regex_call_start;
+    GRegex *regex_call_end;
     GRegex *regex_na;
     GRegex *regex_custom_error;
     /* User-provided parser filter */
@@ -117,7 +121,8 @@ mm_serial_parser_v1_new (void)
     parser->regex_cms_error_str = g_regex_new ("\\r\\n\\+CMS ERROR:\\s*([^\\n\\r]+)\\r\\n", flags, 0, NULL);
     parser->regex_ezx_error = g_regex_new ("\\r\\nMODEM ERROR:\\s*(\\d+)\\r\\n", flags, 0, NULL);
     parser->regex_unknown_error = g_regex_new ("\\r\\n(ERROR)|(COMMAND NOT SUPPORT)\\r\\n", flags, 0, NULL);
-    parser->regex_connect_failed = g_regex_new ("\\r\\n(NO CARRIER)|(BUSY)|(NO ANSWER)|(NO DIALTONE)\\r\\n", flags, 0, NULL);
+    parser->regex_call_start = g_regex_new ("(\\r)?\\n(CONNECT)\\r\\n", flags, 0, NULL);
+    parser->regex_call_end = mm_call_end_regex_get ();
     /* Samsung Z810 may reply "NA" to report a not-available error */
     parser->regex_na = g_regex_new ("\\r\\nNA\\r\\n", flags, 0, NULL);
 
@@ -164,11 +169,33 @@ void
 mm_serial_parser_v1_remove_echo (gpointer    data,
                                  GByteArray *response)
 {
+    MMSerialParserV1 *parser = (MMSerialParserV1 *) data;
     guint i;
 
     if (response->len <= 2)
         return;
 
+    /* Some devices omit the leading <CR> from call end responses which would
+     * otherwise fail the <CR><LF> checks below and be removed. We want to leave
+     * them in the response.
+     */
+    if (g_regex_match_full (parser->regex_call_end,
+                            (const gchar *) response->data,
+                            response->len,
+                            0,
+                            0,
+                            NULL,
+                            NULL))
+        return;
+    if (g_regex_match_full (parser->regex_call_start,
+                            (const gchar *) response->data,
+                            response->len,
+                            0,
+                            0,
+                            NULL,
+                            NULL))
+        return;
+
     for (i = 0; i < (response->len - 1); i++) {
         /* If there is any content before the first
          * <CR><LF>, assume it's echo or garbage, and skip it */
@@ -337,7 +364,7 @@ mm_serial_parser_v1_parse (gpointer   data,
     g_clear_pointer (&match_info, g_match_info_free);
 
     /* Connection failures */
-    found = g_regex_match_full (parser->regex_connect_failed,
+    found = g_regex_match_full (parser->regex_call_end,
                                 response->str, response->len,
                                 0, 0, &match_info, NULL);
     if (found) {
@@ -417,7 +444,8 @@ mm_serial_parser_v1_destroy (gpointer data)
     g_regex_unref (parser->regex_cms_error_str);
     g_regex_unref (parser->regex_ezx_error);
     g_regex_unref (parser->regex_unknown_error);
-    g_regex_unref (parser->regex_connect_failed);
+    g_regex_unref (parser->regex_call_start);
+    g_regex_unref (parser->regex_call_end);
     g_regex_unref (parser->regex_na);
 
     if (parser->regex_custom_successful)

src/tests/test-at-serial-port.c

@@ -46,6 +46,8 @@ static const EchoRemovalTest echo_removal_tests[] = {
     { "echo echo\r\nthis is valid\r\nand so is this", "\r\nthis is valid\r\nand so is this" },
     { "\r\nthis is valid\r\nand so is this", "\r\nthis is valid\r\nand so is this" },
     { "\r\nthis is valid\r\nand so is this\r\n", "\r\nthis is valid\r\nand so is this\r\n" },
+    { "\nNO CARRIER\r\n", "\nNO CARRIER\r\n" },
+    { "\nCONNECT\r\n", "\nCONNECT\r\n" },
 };
 
 static const ParseResponseTest parse_ok_tests[] = {