[pisa-src] r2269 - in trunk/libpisa: sysdep.h sysdep_fw.c

From: Mircea Gherzan <mircea.gherzan@xxxxxxxxxxxxxx>
To: pisa-src@xxxxxxxxxxxxx
Date: Wed, 14 Apr 2010 20:57:25 +0200
Author: gherzan
Date: Wed Apr 14 20:57:25 2010
New Revision: 2269

Log:
libpisa: add ipfw implementation for the firewall wrapper

Modified:
   trunk/libpisa/sysdep.h
   trunk/libpisa/sysdep_fw.c

Modified: trunk/libpisa/sysdep.h
==============================================================================
--- trunk/libpisa/sysdep.h      Wed Apr 14 20:03:31 2010        (r2268)
+++ trunk/libpisa/sysdep.h      Wed Apr 14 20:57:25 2010        (r2269)
@@ -85,7 +85,10 @@
 
 /** firewall command */
 struct firewall_cmd {
-    /** action: add of remove rule */
+    /**
+     * action: add or remove rule. Please leave this at the beginning of the
+     * file, for hashing purposes.
+     */
     short       action;
     /** direction with respect to the local host */
     short       dir;

Modified: trunk/libpisa/sysdep_fw.c
==============================================================================
--- trunk/libpisa/sysdep_fw.c   Wed Apr 14 20:03:31 2010        (r2268)
+++ trunk/libpisa/sysdep_fw.c   Wed Apr 14 20:57:25 2010        (r2269)
@@ -63,11 +63,58 @@
 
 #elif defined(__APPLE__)
 
+/**
+ * Bernstein's hash applied to a firewall command structure.
+ * See http://www.cse.yorku.ca/~oz/hash.html
+ */
+static unsigned int fw_cmd_hash(struct firewall_cmd *cmd)
+{
+    unsigned char *str = (unsigned char*)cmd;
+    unsigned int hash = 5381;
+    int c;
+
+    /* hash only the "constant" part of the command, i.e. the rule.
+     * Hence, we ignore the action (add/delete rule).
+     */
+    str += sizeof(cmd->action);
+
+    while ((c = *str++))
+        hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
+
+    return hash;
+}
+
 int pisa_firewall_do(struct firewall_cmd *cmd)
 {
-    /*TODO: ipfw implementation */
+    char line[CMD_SIZE], temp[CMD_SIZE/4];
+    unsigned int rule_id;
+
+    if ((!cmd->action) || (!cmd->dir) || (!cmd->target)) {
+        return -1;
+    }
+
+    rule_id = fw_cmd_hash(cmd);
+
+    if (cmd->action == FW_DELETE) {
+        snprintf(line, sizeof(line), "ipfw del %u", rule_id);
+        goto out;
+    }
+
+    snprintf(line, sizeof(line), "ipfw add %d %s %s %s ",
+             rule_id,
+             (cmd->target == FW_ACCEPT) ? "allow" : "deny",
+             (cmd->proto == FW_TCP) ? "tcp" : "udp",
+             (cmd->dir == FW_INPUT) ? "from any to me in" :
+                                      "from me to any out");
+
+    if (cmd->iface) {
+        snprintf(temp, sizeof(temp), "via %s", cmd->iface);
+        strcat(line, temp);
+    }
 
-    return 0;
+out:
+    printf("FIREWALL COMMAND: %s\n", line);
+    return system(line);
 }
 
-#endif
+#endif /* OS detection */
[pisa-src] r2269 - in trunk/libpisa: sysdep.h sysdep_fw.c

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