[svn] - new ip cloaking module

[irc/rqf/shadowircd.git] / extensions / ip_cloaking.c

diff --git a/extensions/ip_cloaking.c b/extensions/ip_cloaking.c
index f960d0a938dfcf4c2e0f321688c562c445a835e5..0f0932c930ffdd63e5eb78c61945238770dac3ba 100644 (file)
--- a/extensions/ip_cloaking.c
+++ b/extensions/ip_cloaking.c
@@ -1,4 +1,4 @@
-/* $Id: ip_cloaking.c 2805 2006-12-05 12:45:43Z jilles $ */
+/* $Id: ip_cloaking.c 3522 2007-07-06 07:48:28Z nenolod $ */
 
 #include "stdinc.h"
 #include "modules.h"
@@ -42,7 +42,7 @@ mapi_hfn_list_av1 ip_cloaking_hfnlist[] = {
 };
 
 DECLARE_MODULE_AV1(ip_cloaking, _modinit, _moddeinit, NULL, NULL,
-                       ip_cloaking_hfnlist, "$Revision: 2805 $");
+                       ip_cloaking_hfnlist, "$Revision: 3522 $");
 
 static void
 distribute_hostchange(struct Client *client)
@@ -69,45 +69,82 @@ distribute_hostchange(struct Client *client)
                ClearDynSpoof(client);
 }
 
+#define Nval 0x8c3a48ac
+#define HOSTLEN 63
+#define INITDATA "98fwqefnoiqefv03f423t34gbv3vb89tg432t3b8" /* change this */
+
+static inline unsigned int
+get_string_entropy(const char *inbuf)
+{
+       unsigned int accum = 1;
+
+       while(*inbuf != '\0')
+               accum += *inbuf++;
+
+       return accum;
+}
+
+/* calls get_string_entropy() and toasts it against INITDATA */
+static inline unsigned int
+get_string_weighted_entropy(const char *inbuf)
+{
+       static int base_entropy = 0;
+        unsigned int accum = get_string_entropy(inbuf);
+
+       /* initialize the algorithm if it is not yet ready */
+       if (base_entropy == 0)
+               base_entropy = get_string_entropy(INITDATA);
+
+        return (Nval * accum) ^ base_entropy;
+}
+
 static void
-do_host_cloak(const char *inbuf, char *outbuf, int ipmask)
+do_host_cloak_ip(const char *inbuf, char *outbuf)
 {
-       int cyc;
-       unsigned int hosthash = 1, hosthash2 = 1;
-       unsigned int maxcycle = strlen(inbuf);  
-       int len1;
-       const char *rest, *next;
-
-       for (cyc = 0; cyc < maxcycle - 2; cyc += 2)
-               hosthash *= (unsigned int) inbuf[cyc];
-
-       /* safety: decrement ourselves two steps back */
-       for (cyc = maxcycle - 1; cyc >= 1; cyc -= 2)
-               hosthash2 *= (unsigned int) inbuf[cyc];
-
-       /* lets do some bitshifting -- this pretty much destroys the IP
-        * sequence, while still providing a checksum. exactly what
-        * we're shooting for. --nenolod
-        */
-       hosthash += (hosthash2 / KEY);
-       hosthash2 += (hosthash / KEY);
+       char *tptr;
+       unsigned int accum = get_string_weighted_entropy(inbuf);
+       char buf[HOSTLEN];
+
+       strncpy(buf, inbuf, HOSTLEN);
+       tptr = strrchr(buf, '.');
+       *tptr++ = '\0';
 
-       if (ipmask == 0)
+       snprintf(outbuf, HOSTLEN, "%s.%x", buf, accum);
+}
+
+static void
+do_host_cloak_host(const char *inbuf, char *outbuf)
+{
+       char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
+       char *tptr;
+       unsigned int accum = get_string_weighted_entropy(inbuf);
+
+       strncpy(outbuf, inbuf, HOSTLEN);
+
+       /* pass 1: scramble first section of hostname using base26 
+        * alphabet toasted against the weighted entropy of the string.
+        *
+        * numbers are not changed at this time, only letters.
+        */
+       for (tptr = outbuf; *tptr != '\0'; tptr++)
        {
-               ircsnprintf(outbuf, HOSTLEN, "%s-%X%X",
-                       ServerInfo.network_name, hosthash2, hosthash);
-               len1 = strlen(outbuf);
-               rest = strchr(inbuf, '.');
-               if (rest == NULL)
-                       rest = ".";
-               /* try to avoid truncation -- jilles */
-               while (len1 + strlen(rest) >= HOSTLEN && (next = strchr(rest + 1, '.')) != NULL)
-                       rest = next;
-               strlcat(outbuf, rest, HOSTLEN);
+               if (*tptr == '.')
+                       break;
+
+               if (isdigit(*tptr) || *tptr == '-')
+                       continue;
+
+               *tptr = b26_alphabet[(*tptr * accum) % 26];
        }
-       else
-               ircsnprintf(outbuf, HOSTLEN, "%X%X.%s",
-                       hosthash2, hosthash, ServerInfo.network_name);
+
+       /* pass 2: scramble each number in the address */
+       for (tptr = outbuf; *tptr != '\0'; tptr++)
+       {
+               if (isdigit(*tptr))
+               {
+                       *tptr = 48 + ((*tptr * accum) % 10);
+               }
+       }       
 }
 
 static void
@@ -162,9 +199,9 @@ check_new_user(void *vdata)
        }
        source_p->localClient->mangledhost = MyMalloc(HOSTLEN);
        if (!irccmp(source_p->orighost, source_p->sockhost))
-               do_host_cloak(source_p->orighost, source_p->localClient->mangledhost, 1);
+               do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost);
        else
-               do_host_cloak(source_p->orighost, source_p->localClient->mangledhost, 0);
+               do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost);
        if (IsDynSpoof(source_p))
                source_p->umodes &= ~user_modes['h'];
        if (source_p->umodes & user_modes['h'])