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#include <iostream>
#include <sstream>
#include <unistd.h> /* gethostname */
#include "sepofra.h"
#include "utils.h" /* for trim() */
#ifndef HOST_NAME_MAX
#define HOST_NAME_MAX 255
#endif
///// Important reference:
///// http://www.ietf.org/rfc/rfc4408.txt
/////
using namespace std;
string domain_part(const string ema){
size_t where = ema.find('@');
if (where != ema.npos){
return ema.substr(1+where);
}
return ema;
}
// strips off one level of domain name,
// provided that at least two levels remain.
// foo.bar.com --> bar.com
// bar.com --> bar.com
// ..foo.bar.com --> bar.com
string subdomain2plus(const string ema){
string sub(ema);
while (sub[0] == '.') sub = sub.substr(1);
size_t where = sub.find('.');
if (where == string::npos) return ema;
sub = sub.substr(1+where);
if (sub.find(".") == string::npos) return ema;
return sub;
}
SPF_result_t sepofra::check1(const string _host,
const string msg, const int debug){
string host(_host);
size_t where = host.find("@");
if (where != string::npos){
host = host.substr(1+where);
}
if (!host.length()) return SPF_RESULT_INVALID;
if (seen.find(host) != seen.end()) {
// already checked this one
return seen[host];
}
seen[host] = SPF_RESULT_TEMPERROR;
authorities.push_back(host);
if (SPF_request_set_env_from( spf_request,
host.c_str() ) ) {
throw bad_thing (("Invalid " + msg + ": " + host).c_str());
}
if (spf_response) SPF_response_free(spf_response);
SPF_request_query_mailfrom(spf_request, &spf_response);
if (debug) dumpit(debug, spf_response, "");
return seen[host] = SPF_response_result(spf_response);
}
void sepofra::check(
const string opt_ip,
const string opt_helo,
const string opt_mailfrom,
const string opt_rcpt_to,
const int opt_debug)
{
SPF_server_t* spf_server = NULL;
sepofra rslt;
ip = opt_ip;
helo = trim(opt_helo, " \t\r\n<.>");
mailfrom = trim(opt_mailfrom, " \t\r\n<.>");
string mailfrom_domain = domain_part(opt_mailfrom);
do {
spf_server = SPF_server_new(SPF_DNS_CACHE, opt_debug);
if (spf_server == NULL) {
cerr << "SPF_server_new failed" << endl;
break;
}
spf_request = SPF_request_new(spf_server);
if (spf_request == NULL) {
cerr << "sepofra::check SPF_request_new failed" << endl;
break;
}
if ( SPF_request_set_ipv4_str( spf_request, opt_ip.c_str() )
&& SPF_request_set_ipv6_str( spf_request, opt_ip.c_str() ) ) {
cerr << "sepofra::check: Invalid IP address: '"
<< opt_ip << "'" << endl;
break;
}
result = check1(opt_helo, "HELO domain", opt_debug);
if (result == SPF_RESULT_PASS) break;
if (result == SPF_RESULT_FAIL) break;
result = check1(mailfrom, "MAILFROM domain", opt_debug);
if (result == SPF_RESULT_PASS) break;
if (result == SPF_RESULT_FAIL) break;
result = check1(subdomain2plus(opt_helo), "HELO subdomain", opt_debug);
if (result == SPF_RESULT_PASS) break;
if (result == SPF_RESULT_FAIL) break;
result = check1(subdomain2plus(mailfrom), "MAILFROM domain", opt_debug);
if (result == SPF_RESULT_PASS) break;
if (result == SPF_RESULT_FAIL) break;
} while(0);
if (spf_response) SPF_response_free(spf_response);
if (spf_request) SPF_request_free(spf_request);
if (spf_server) SPF_server_free(spf_server);
return;
}
// return "" if result is invalid
// otherwise build a string explaining how SPF reached its conclusion
string sepofra::explain() const {
if (result == SPF_RESULT_INVALID) return "";
stringstream build;
string summary = SPF_strresult(result);
if (result != SPF_RESULT_PASS
&& result != SPF_RESULT_FAIL
&& result != SPF_RESULT_INVALID) summary = "neutral";
char hostname[1+HOST_NAME_MAX];
gethostname(hostname, 1+HOST_NAME_MAX);
build << "Received-SPF: ";
build << summary;
build << " (" << hostname; /* ) */
build << ": sender " << ip;
if (result == SPF_RESULT_PASS){
build << " is approved by {"
<< authorities.back()
<< "}";
} else if (result == SPF_RESULT_FAIL){
build << " is forbidden by {"
<< authorities.back()
<< "}";
} else {
build << " is neither approved nor forbidden by {";
int didsome(0);
for (list<string>::const_iterator ptr = authorities.begin();
ptr != authorities.end(); ptr++) {
if (didsome++) build << " ";
build << *ptr;
}
build << "}";
}
/* ( */ build << ")";
if (ip != "") build << " client-ip=" << ip << ";";
if (mailfrom != "") build << " envelope-from=" << mailfrom << ";";
if (helo != "") build << " helo=" << helo;
return build.str();
}
void dumpit(const int opt_debug,
SPF_response_t* spf_response,
const char* msg) {
int i;
printf("---- %s\n", msg);
if ( opt_debug > 0 ) {
printf ( "result = %s (%d)\n",
SPF_strresult(SPF_response_result(spf_response)),
SPF_response_result(spf_response));
printf ( "err = %s (%d)\n",
SPF_strerror(SPF_response_errcode(spf_response)),
SPF_response_errcode(spf_response));
for (i = 0; i < SPF_response_messages(spf_response); i++) {
SPF_error_t *err = SPF_response_message(spf_response, i);
printf ( "%s_msg = (%d) %s\n",
(SPF_error_errorp(err) ? "warn" : "err"),
SPF_error_code(err),
SPF_error_message(err));
}
}
#define VALID_STR(x) (x ? x : "")
printf("Bottom line result: %s\n",
SPF_strresult( SPF_response_result(spf_response)));
printf("Reason: %s\n", SPF_strreason(spf_response->reason));
printf("SMTP comment: %s\n",
VALID_STR(SPF_response_get_smtp_comment(spf_response)));
printf("Header comment: %s\n",
VALID_STR(SPF_response_get_header_comment(spf_response)));
printf("Received spf: %s\n",
VALID_STR(SPF_response_get_received_spf(spf_response)));
}
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