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;
int previous = -1;
REMAILER remailer[MAXREM];
int badchains[MAXREM][MAXREM];
/* chaintype 0=mix 1=ek 2=newnym */
assert((chaintype == 0) || (chaintype == 1));
maxrem = (chaintype == 0 ? mix2_rlist(remailer, badchains) : t1_rlist(remailer, badchains));
/* 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;
if (previous != -1) {
if (badchains[previous][i] || badchains[0][i])
acc_reliability = 0;
}
previous = i;
} 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;
}
int t1_encrypt(int type, BUFFER *message, char *chainstr, int latency,
BUFFER *ek, BUFFER *feedback)
{
BUFFER *b, *rem, *dest, *line, *field, *content;
REMAILER remailer[MAXREM];
int badchains[MAXREM][MAXREM];
int maxrem, chainlen = 0;
int chain[20];
int hop;
int hashmark = 0;
int err = 0;
b = buf_new();
rem = buf_new();
dest = buf_new();
line = buf_new();
field = buf_new();
content = buf_new();
maxrem = t1_rlist(remailer, badchains);
if (maxrem < 1) {
clienterr(feedback, "No remailer list!");
err = -1;
goto end;
}
chainlen = chain_select(chain, chainstr, maxrem, remailer, 1, line);
if (chainlen < 1) {
if (line->length)
clienterr(feedback, line->data);
else
clienterr(feedback, "Invalid remailer chain!");
err = -1;
goto end;
}
if (chain[0] == 0)
chain[0] = chain_randfinal(type, remailer, badchains, maxrem, 1, chain, chainlen, 0);
if (chain[0] == -1) {
clienterr(feedback, "Invalid remailer chain!");
err = -1;
goto end;
}
if (chain_rand(remailer, badchains, maxrem, chain, chainlen, 1, 0) == -1) {
clienterr(feedback, "No reliable remailers!");
err = -1;
goto end;
}
while (buf_getheader(message, field, content) == 0) {
hdr_encode(content, 0);
if (type == MSG_POST && bufieq(field, "newsgroups") &&
remailer[chain[0]].flags.post) {
buf_appendf(dest, "Anon-Post-To: %b\n", content);
} else if (type == MSG_MAIL && bufieq(field, "to")) {
buf_appendf(dest, "Anon-To: %b\n", content);
} else {
/* paste header */
if (type == MSG_POST && bufieq(field, "newsgroups"))
buf_appendf(dest, "Anon-To: %s\n", MAILtoNEWS);
if (hashmark == 0) {
buf_appends(b, "##\n");
hashmark = 1;
}
buf_appendheader(b, field, content);
}
}
buf_nl(b);
buf_rest(b, message);
buf_move(message, b);
if (type != MSG_NULL && dest->length == 0) {
clienterr(feedback, "No destination address!");
err = -1;
goto end;
}
if (type == MSG_NULL) {
buf_sets(dest, "Null:\n");
}
for (hop = 0; hop < chainlen; hop++) {
if (hop == 0) {
buf_sets(b, "::\n");
buf_cat(b, dest);
} else {
buf_sets(b, "::\nAnon-To: ");
buf_appends(b, remailer[chain[hop - 1]].addr);
buf_nl(b);
}
if (remailer[chain[hop]].flags.latent && latency > 0)
buf_appendf(b, "Latent-Time: +%d:00r\n", latency);
if (ek && remailer[chain[hop]].flags.ek) {
t1_ek(line, ek, hop);
buf_appendf(b, "Encrypt-Key: %b\n", line);
}
buf_nl(b);
buf_cat(b, message);
#ifdef USE_PGP
if (remailer[chain[hop]].flags.pgp) {
buf_clear(message);
buf_clear(rem);
buf_setf(rem, "<%s>", remailer[chain[hop]].addr);
err = pgp_encrypt(PGP_ENCRYPT | PGP_REMAIL | PGP_TEXT, b, rem,
NULL, NULL, NULL, NULL);
if (err < 0) {
buf_setf(line, "No PGP key for remailer %s!\n",
remailer[chain[hop]].name);
clienterr(feedback, line->data);
goto end;
}
buf_appends(message, "::\nEncrypted: PGP\n\n");
buf_cat(message, b);
} else
#endif /* USE_PGP */
{
if (remailer[chain[hop]].flags.pgponly) {
buf_setf(line, "PGP encryption needed for remailer %s!\n",
remailer[chain[hop]].name);
clienterr(feedback, line->data);
goto end;
}
buf_move(message, b);
}
if (ek && remailer[chain[hop]].flags.ek)
buf_appends(message, "\n**\n");
}
buf_clear(b);
if (chainlen == 0) {
buf_appends(b, "::\n");
buf_cat(b, dest);
} else {
buf_appendf(b, "%s: %s\n", ek ? "::\nAnon-To" : "To",
remailer[chain[chainlen - 1]].addr);
}
buf_nl(b);
buf_cat(b, message);
buf_move(message, b);
end:
buf_free(b);
buf_free(rem);
buf_free(dest);
buf_free(line);
buf_free(field);
buf_free(content);
return (err);
}