Mix/Src/chain.c

/* Mixmaster version 3  --  (C) 1999 Anonymizer Inc.

   Mixmaster may be redistributed and modified under certain conditions.
   This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF
   ANY KIND, either express or implied. See the file COPYRIGHT for
   details.

   Prepare messages for remailer chain
   $Id: chain.c,v 1.2 2001/12/11 09:02:16 rabbi Exp $ */


#include "mix3.h"
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include <stdlib.h>

void clienterr(BUFFER *msgbuf, char *err)
{
  if (msgbuf) {
    buf_sets(msgbuf, "Error: ");
    buf_appends(msgbuf, err);
  } else
    errlog(ERRORMSG, "%s\n", err);
}

int chain_select(int hop[], char *chainstr, int maxrem, REMAILER *remailer,
                 int type, BUFFER *feedback)
{
  int len = 0;
  int i, j, k;
  BUFFER *chain, *selected, *addr;
  chain = buf_new();
  selected = buf_new();
  addr = buf_new();

  if (chainstr == NULL || chainstr[0] == '\0')
    buf_sets(chain, CHAIN);
  else
    buf_sets(chain, chainstr);

  /* put the chain backwards: final hop is in hop[0] */

  for (i = chain->length; i >= 0; i--)
    if (i == 0 || chain->data[i - 1] <= ' ' || chain->data[i - 1] == ','
        || chain->data[i - 1] == ';' || chain->data[i - 1] == ':') {
      for (j = i; isspace(chain->data[j]);)     /* ignore whitespace */
        j++;
      if (chain->data[j] == '\0')
        break;

      if (chain->data[j] == '*')
        k = 0;
#if 0
      else if (isdigit(chain->data[j]))
        k = atoi(chain->data + j);
#endif
      else {
        buf_sets(selected, chain->data + j);
        rfc822_addr(selected, addr);
        buf_clear(selected);
        buf_getline(addr, selected);
        if (!selected->length)
          buf_sets(selected, chain->data + j);

        for (k = 0; k < maxrem; k++)
          if (((remailer[k].flags.mix && type == 0) ||
               (remailer[k].flags.cpunk && type == 1) ||
               (remailer[k].flags.newnym && type == 2)) &&
              (streq(remailer[k].name, selected->data) ||
               strieq(remailer[k].addr, selected->data) ||
               (selected->data[0] == '@' && strifind(remailer[k].addr,
                                            selected->data))))
            break;
      }
      if (k < 0 || k >= maxrem) {
        buf_appendf(feedback, "No such remailer: %b", selected);
        buf_nl(feedback);
#if 0
        k = 0;
#else
        len = -1;
        goto end;
#endif
      }
      hop[len++] = k;
      if (len >= 20) {          /* array passed in is has length 20 */
        buf_appends(feedback, "Chain too long.\n");
        break;
      }
      if (i > 0)
        chain->data[i - 1] = '\0';
    }
end:
  buf_free(chain);
  buf_free(selected);
  buf_free(addr);
  return len;
}

int chain_randfinal(int type, REMAILER *remailer, int maxrem, int rtype)
{
  int num = 0;
  int i;
  int t;

  t = rtype;
  if (rtype == 2)
    t = 1;

  /* select a random final hop */
  for (i = 1; i < maxrem; i++) {
    if (((remailer[i].flags.mix && rtype == 0) ||
         (remailer[i].flags.pgp && remailer[i].flags.ek && rtype == 1) ||
         (remailer[i].flags.newnym && rtype == 2)) &&
        remailer[i].info[t].reliability >= 100 * RELFINAL &&
        remailer[i].info[t].latency <= MAXLAT &&
        (type == MSG_NULL || !remailer[i].flags.middle) &&
        (remailer[i].flags.post || type != MSG_POST))
      num++;
  }
  if (num == 0)
    i = -1;
  else {
    do
      i = rnd_number(maxrem) + 1;
    while (!(((remailer[i].flags.mix && rtype == 0) ||
              (remailer[i].flags.pgp && remailer[i].flags.ek && rtype == 1) ||
              (remailer[i].flags.newnym && rtype == 2)) &&
             remailer[i].info[t].reliability >= 100 * RELFINAL &&
             remailer[i].info[t].latency <= MAXLAT &&
             (type == MSG_NULL || !remailer[i].flags.middle) &&
             (remailer[i].flags.post || type != MSG_POST)));
  }
  return (i);
}

int chain_rand(REMAILER *remailer, int maxrem,
               int thischain[], int chainlen, int t)
     /* set random chain. returns 0 if not random, 1 if random, -1 on error */
{
  int hop;
  int err = 0;

  assert(t == 0 || t == 1);

  for (hop = 0; hop < chainlen; hop++)
    if (thischain[hop] == 0) {
      int select[MAXREM];
      int randavail = 0;
      int i;

      err = 1;
      for (i = 1; i < maxrem; i++)
        select[i] = ((remailer[i].flags.mix && t == 0) ||
                     (remailer[i].flags.pgp && remailer[i].flags.ek && t == 1))
          && remailer[i].info[t].reliability >= 100 * MINREL &&
          remailer[i].info[t].latency <= MAXLAT,
          randavail += select[i];

      for (i = hop - DISTANCE; i <= hop + DISTANCE; i++)
        if (i >= 0 && i < chainlen && select[thischain[i]])
          select[thischain[i]] = 0, randavail--;

      if (randavail < 1) {
        err = -1;
        goto end;
      }
      do
        thischain[hop] = rnd_number(maxrem - 1) + 1;
      while (!select[thischain[hop]]);
    }
end:
  return (err);
}

int mix_encrypt(int type, BUFFER *message, char *chainstr, int numcopies,
                BUFFER *chainlist)
{
  return (mix2_encrypt(type, message, chainstr, numcopies, chainlist));
}

/* float chain_reliablity(char *chain, int chaintype,
                          char *reliability_string);
 *
 * Compute reliablity of a chain.
 *
 * We get the reliablity of the chain by multiplying the reliablity of
 * every remailer in the chain. The return value is the reliablity of
 * the chain, or a negative number if the reliablity can not be
 * calculated. There are two reasons why may not be able to calculated
 * the reliablity: A remailer in the chain is selected randomly, or we
 * don't have statistics about one of the remailers in the chain.
 * remailer_type indicates the remailer type:
 * 0 = Mixmaster, 1 = Cypherpunk
 *
 * If reliability_string is non-NULL, the reliability is also returned
 * as a string in this variable. The size of the string must be at
 * least 9 characters!
 *
 * This function has been added by Gerd Beuster. (gb@uni-koblenz.de)
 *--------------------------------------------------------------------*/

float chain_reliability(char *chain, int chaintype,
                        char *reliability_string){
  
  float acc_reliability = 1; /* Accumulated reliablity */
  char *name_start, *name_end; /* temporary pointers used
                                 in string scanning */
  char remailer_name[20]; /* The length of the array is taken from mix3.h. */
  int error = 0;
  int maxrem;
  int i;
  REMAILER remailer[MAXREM];

  /* chaintype 0=mix 1=ek 2=newnym */
  assert((chaintype == 0) || (chaintype == 1));
  maxrem = (chaintype == 0 ? mix2_rlist(remailer) : t1_rlist(remailer));

  /* Dissect chain */
  name_start = chain;
  name_end = chain;
  while(*name_end != '\0'){ /* While string not scanned completely */
    do /* Get next remailer */
      name_end+=sizeof(char);
    while( (*name_end != ',') && (*name_end != '\0'));
    strncpy(remailer_name, name_start,
            (name_end - name_start) / sizeof(char) + 1*sizeof(char));
    remailer_name[name_end-name_start]='\0';
    /* Lookup reliablity for remailer remailer_name */
    for(i=0;
        (i < maxrem) && (strcmp(remailer[i].name, remailer_name) != 0);
        i++);
    if(!strcmp(remailer[i].name, remailer_name)) /* Found it! */
      acc_reliability *=
        ((float) remailer[i].info[chaintype].reliability) / 10000;
    else
      error = 1; /* Did not find this remailer. We can't calculate
                    the reliablity for the whole chain. */
    name_start = name_end+sizeof(char);
  }

  if(error || (name_start==name_end))
    acc_reliability = -1;

  /* Convert reliability into string, if appropriate */
  if(reliability_string){
    if(acc_reliability < 0)
      sprintf(reliability_string, "  n/a  ");
    else{
      sprintf(reliability_string, "%6.2f", acc_reliability*100);
      *(reliability_string+6*sizeof(char)) = '%';
    }
  }
  
  return acc_reliability;
}
  
1	/* Mixmaster version 3 -- (C) 1999 Anonymizer Inc.
2
3	Mixmaster may be redistributed and modified under certain conditions.
4	This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF
5	ANY KIND, either express or implied. See the file COPYRIGHT for
6	details.
7
8	Prepare messages for remailer chain
9	$Id: chain.c,v 1.2 2001/12/11 09:02:16 rabbi Exp $ */
10
11
12	#include "mix3.h"
13	#include <string.h>
14	#include <ctype.h>
15	#include <assert.h>
16	#include <stdlib.h>
17
18	void clienterr(BUFFER msgbuf, char err)
19	{
20	if (msgbuf) {
21	buf_sets(msgbuf, "Error: ");
22	buf_appends(msgbuf, err);
23	} else
24	errlog(ERRORMSG, "%s\n", err);
25	}
26
27	int chain_select(int hop[], char chainstr, int maxrem, REMAILER remailer,
28	int type, BUFFER *feedback)
29	{
30	int len = 0;
31	int i, j, k;
32	BUFFER chain, selected, *addr;
33	chain = buf_new();
34	selected = buf_new();
35	addr = buf_new();
36
37	if (chainstr == NULL \|\| chainstr[0] == '\0')
38	buf_sets(chain, CHAIN);
39	else
40	buf_sets(chain, chainstr);
41
42	/* put the chain backwards: final hop is in hop[0] */
43
44	for (i = chain->length; i >= 0; i--)
45	if (i == 0 \|\| chain->data[i - 1] <= ' ' \|\| chain->data[i - 1] == ','
46	\|\| chain->data[i - 1] == ';' \|\| chain->data[i - 1] == ':') {
47	for (j = i; isspace(chain->data[j]);) /* ignore whitespace */
48	j++;
49	if (chain->data[j] == '\0')
50	break;
51
52	if (chain->data[j] == '*')
53	k = 0;
54	#if 0
55	else if (isdigit(chain->data[j]))
56	k = atoi(chain->data + j);
57	#endif
58	else {
59	buf_sets(selected, chain->data + j);
60	rfc822_addr(selected, addr);
61	buf_clear(selected);
62	buf_getline(addr, selected);
63	if (!selected->length)
64	buf_sets(selected, chain->data + j);
65
66	for (k = 0; k < maxrem; k++)
67	if (((remailer[k].flags.mix && type == 0) \|\|
68	(remailer[k].flags.cpunk && type == 1) \|\|
69	(remailer[k].flags.newnym && type == 2)) &&
70	(streq(remailer[k].name, selected->data) \|\|
71	strieq(remailer[k].addr, selected->data) \|\|
72	(selected->data[0] == '@' && strifind(remailer[k].addr,
73	selected->data))))
74	break;
75	}
76	if (k < 0 \|\| k >= maxrem) {
77	buf_appendf(feedback, "No such remailer: %b", selected);
78	buf_nl(feedback);
79	#if 0
80	k = 0;
81	#else
82	len = -1;
83	goto end;
84	#endif
85	}
86	hop[len++] = k;
87	if (len >= 20) { /* array passed in is has length 20 */
88	buf_appends(feedback, "Chain too long.\n");
89	break;
90	}
91	if (i > 0)
92	chain->data[i - 1] = '\0';
93	}
94	end:
95	buf_free(chain);
96	buf_free(selected);
97	buf_free(addr);
98	return len;
99	}
100
101	int chain_randfinal(int type, REMAILER *remailer, int maxrem, int rtype)
102	{
103	int num = 0;
104	int i;
105	int t;
106
107	t = rtype;
108	if (rtype == 2)
109	t = 1;
110
111	/* select a random final hop */
112	for (i = 1; i < maxrem; i++) {
113	if (((remailer[i].flags.mix && rtype == 0) \|\|
114	(remailer[i].flags.pgp && remailer[i].flags.ek && rtype == 1) \|\|
115	(remailer[i].flags.newnym && rtype == 2)) &&
116	remailer[i].info[t].reliability >= 100 * RELFINAL &&
117	remailer[i].info[t].latency <= MAXLAT &&
118	(type == MSG_NULL \|\| !remailer[i].flags.middle) &&
119	(remailer[i].flags.post \|\| type != MSG_POST))
120	num++;
121	}
122	if (num == 0)
123	i = -1;
124	else {
125	do
126	i = rnd_number(maxrem) + 1;
127	while (!(((remailer[i].flags.mix && rtype == 0) \|\|
128	(remailer[i].flags.pgp && remailer[i].flags.ek && rtype == 1) \|\|
129	(remailer[i].flags.newnym && rtype == 2)) &&
130	remailer[i].info[t].reliability >= 100 * RELFINAL &&
131	remailer[i].info[t].latency <= MAXLAT &&
132	(type == MSG_NULL \|\| !remailer[i].flags.middle) &&
133	(remailer[i].flags.post \|\| type != MSG_POST)));
134	}
135	return (i);
136	}
137
138	int chain_rand(REMAILER *remailer, int maxrem,
139	int thischain[], int chainlen, int t)
140	/* set random chain. returns 0 if not random, 1 if random, -1 on error */
141	{
142	int hop;
143	int err = 0;
144
145	assert(t == 0 \|\| t == 1);
146
147	for (hop = 0; hop < chainlen; hop++)
148	if (thischain[hop] == 0) {
149	int select[MAXREM];
150	int randavail = 0;
151	int i;
152
153	err = 1;
154	for (i = 1; i < maxrem; i++)
155	select[i] = ((remailer[i].flags.mix && t == 0) \|\|
156	(remailer[i].flags.pgp && remailer[i].flags.ek && t == 1))
157	&& remailer[i].info[t].reliability >= 100 * MINREL &&
158	remailer[i].info[t].latency <= MAXLAT,
159	randavail += select[i];
160
161	for (i = hop - DISTANCE; i <= hop + DISTANCE; i++)
162	if (i >= 0 && i < chainlen && select[thischain[i]])
163	select[thischain[i]] = 0, randavail--;
164
165	if (randavail < 1) {
166	err = -1;
167	goto end;
168	}
169	do
170	thischain[hop] = rnd_number(maxrem - 1) + 1;
171	while (!select[thischain[hop]]);
172	}
173	end:
174	return (err);
175	}
176
177	int mix_encrypt(int type, BUFFER message, char chainstr, int numcopies,
178	BUFFER *chainlist)
179	{
180	return (mix2_encrypt(type, message, chainstr, numcopies, chainlist));
181	}
182
183	/* float chain_reliablity(char *chain, int chaintype,
184	char *reliability_string);
185	*
186	* Compute reliablity of a chain.
187	*
188	* We get the reliablity of the chain by multiplying the reliablity of
189	* every remailer in the chain. The return value is the reliablity of
190	* the chain, or a negative number if the reliablity can not be
191	* calculated. There are two reasons why may not be able to calculated
192	* the reliablity: A remailer in the chain is selected randomly, or we
193	* don't have statistics about one of the remailers in the chain.
194	* remailer_type indicates the remailer type:
195	* 0 = Mixmaster, 1 = Cypherpunk
196	*
197	* If reliability_string is non-NULL, the reliability is also returned
198	* as a string in this variable. The size of the string must be at
199	* least 9 characters!
200	*
201	* This function has been added by Gerd Beuster. (gb@uni-koblenz.de)
202	--------------------------------------------------------------------/
203
204	float chain_reliability(char *chain, int chaintype,
205	char *reliability_string){
206
207	float acc_reliability = 1; /* Accumulated reliablity */
208	char name_start, name_end; /* temporary pointers used
209	in string scanning */
210	char remailer_name[20]; /* The length of the array is taken from mix3.h. */
211	int error = 0;
212	int maxrem;
213	int i;
214	REMAILER remailer[MAXREM];
215
216	/* chaintype 0=mix 1=ek 2=newnym */
217	assert((chaintype == 0) \|\| (chaintype == 1));
218	maxrem = (chaintype == 0 ? mix2_rlist(remailer) : t1_rlist(remailer));
219
220	/* Dissect chain */
221	name_start = chain;
222	name_end = chain;
223	while(name_end != '\0'){ / While string not scanned completely */
224	do /* Get next remailer */
225	name_end+=sizeof(char);
226	while( (name_end != ',') && (name_end != '\0'));
227	strncpy(remailer_name, name_start,
228	(name_end - name_start) / sizeof(char) + 1*sizeof(char));
229	remailer_name[name_end-name_start]='\0';
230	/* Lookup reliablity for remailer remailer_name */
231	for(i=0;
232	(i < maxrem) && (strcmp(remailer[i].name, remailer_name) != 0);
233	i++);
234	if(!strcmp(remailer[i].name, remailer_name)) /* Found it! */
235	acc_reliability *=
236	((float) remailer[i].info[chaintype].reliability) / 10000;
237	else
238	error = 1; /* Did not find this remailer. We can't calculate
239	the reliablity for the whole chain. */
240	name_start = name_end+sizeof(char);
241	}
242
243	if(error \|\| (name_start==name_end))
244	acc_reliability = -1;
245
246	/* Convert reliability into string, if appropriate */
247	if(reliability_string){
248	if(acc_reliability < 0)
249	sprintf(reliability_string, " n/a ");
250	else{
251	sprintf(reliability_string, "%6.2f", acc_reliability*100);
252	(reliability_string+6sizeof(char)) = '%';
253	}
254	}
255
256	return acc_reliability;
257	}
258