Pass an HTTP message type to all HTTP subdissectors.

This gets complicated, because those subdissectors might be called by
other dissectors as well.  We need a better way of passing that sort of
out-of-bound information.

Pull some routines used for processing Content-Type parameters into
common code; we can't guarantee that the media parameters passed in
would be writable (passing it as *the* data hid that; passing a
structure with that *and* the HTTP message type revealed it), so don't
convert it to lower-case in place.

Use that information, if available, to determine whether an IPP message
is a requet or a response.

Change-Id: I4bccc9f05cd0b14ad445be7ab37b3d884d841325
Reviewed-on: https://code.wireshark.org/review/17216
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 133 insertions, 0 deletions

diff --git a/epan/media_params.c b/epan/media_params.c
new file mode 100644
index 0000000000..863025b437
--- /dev/null
+++ b/epan/media_params.c
@@ -0,0 +1,133 @@
+/* media_params.c
+ * Routines for parsing media type parameters
+ * Copyright 2004, Anders Broman.
+ * Copyright 2004, Olivier Biot.
+ *
+ * Refer to the AUTHORS file or the AUTHORS section in the man page
+ * for contacting the author(s) of this file.
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+
+#include <string.h>
+
+#include <glib.h>
+
+#include <epan/media_params.h>
+
+/* Return the index of a given char in the given string,
+ * or -1 if not found.
+ */
+gint
+index_of_char(const char *str, const char c)
+{
+    gint len = 0;
+    const char *p = str;
+
+    while (*p && *p != c) {
+        p++;
+        len++;
+    }
+
+    if (*p)
+        return len;
+    return -1;
+}
+
+char *
+find_parameter(const char *parameters, const char *key, int *retlen)
+{
+    const char *start, *p;
+    int   keylen = 0;
+    int   len = 0;
+
+    if(!parameters || !*parameters || !key || strlen(key) == 0)
+        /* we won't be able to find anything */
+        return NULL;
+
+    keylen = (int) strlen(key);
+    p = parameters;
+
+    while (*p) {
+
+        while ((*p) && g_ascii_isspace(*p))
+            p++; /* Skip white space */
+
+        if (g_ascii_strncasecmp(p, key, keylen) == 0)
+            break;
+        /* Skip to next parameter */
+        p = strchr(p, ';');
+        if (p == NULL)
+        {
+            return NULL;
+        }
+        p++; /* Skip semicolon */
+
+    }
+    if (*p == 0x0)
+        return NULL;  /* key wasn't found */
+
+    start = p + keylen;
+    if (start[0] == 0) {
+        return NULL;
+    }
+
+    /*
+     * Process the parameter value
+     */
+    if (start[0] == '"') {
+        /*
+         * Parameter value is a quoted-string
+         */
+        start++; /* Skip the quote */
+        len = index_of_char(start, '"');
+        if (len < 0) {
+            /*
+             * No closing quote
+             */
+            return NULL;
+        }
+    } else {
+        /*
+         * Look for end of boundary
+         */
+        p = start;
+        while (*p) {
+            if (*p == ';' || g_ascii_isspace(*p))
+                break;
+            p++;
+            len++;
+        }
+    }
+
+    if(retlen)
+        (*retlen) = len;
+
+    /*
+     * This is one of those ugly routines like strchr() where you can
+     * pass in a constant or non-constant string, and the result
+     * points into that string and inherits the constness of the
+     * input argument, but C doesn't support that, so the input
+     * parameter is const char * and the result is char *.
+     */
+    return (char *)start;
+}
+