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/* Copyright 2007 Roger Dingledine, Nick Mathewson */
/* See LICENSE for licensing information */
/* $Id$ */
const char dnsserv_c_id[] =
"$Id$";
/**
* \file dnservs.c
* \brief Implements client-side DNS proxy server code.
**/
#include "or.h"
#include "eventdns.h"
static void
evdns_server_callback(struct evdns_server_request *req, void *_data)
{
edge_connection_t *conn;
int i = 0;
struct evdns_server_question *q = NULL;
struct sockaddr_storage addr;
struct sockaddr *sa;
int addrlen;
uint32_t ipaddr;
int err = DNS_ERR_NONE;
tor_assert(req);
tor_assert(_data == NULL);
log_info(LD_APP, "Got a new DNS request!");
if ((addrlen = evdns_server_request_get_requesting_addr(req,
(struct sockaddr*)&addr, sizeof(addr))) < 0) {
log_warn(LD_APP, "Couldn't get requesting address.");
evdns_server_request_respond(req, DNS_ERR_SERVERFAILED);
return;
}
sa = (struct sockaddr*) &addr;
if (sa->sa_family != AF_INET) {
/* XXXX020 Handle IPV6 */
log_warn(LD_APP, "Requesting address wasn't ipv4.");
evdns_server_request_respond(req, DNS_ERR_SERVERFAILED);
return;
} else {
struct sockaddr_in *sin = (struct sockaddr_in*)&addr;
ipaddr = ntohl(sin->sin_addr.s_addr);
}
if (!socks_policy_permits_address(ipaddr)) {
log_warn(LD_APP, "Rejecting DNS request from disallowed IP.");
evdns_server_request_respond(req, DNS_ERR_REFUSED);
return;
}
if (req->nquestions == 0) {
log_info(LD_APP, "No questions in DNS request; sending back nil reply.");
evdns_server_request_respond(req, 0);
return;
}
if (req->nquestions > 1) {
log_info(LD_APP, "Got a DNS request with more than one question; I only "
"handle one question at a time for now. Skipping the extras.");
}
for (i = 0; i < req->nquestions; ++i) {
if (req->questions[i]->class != EVDNS_CLASS_INET)
continue;
switch (req->questions[i]->type) {
case EVDNS_TYPE_A:
case EVDNS_TYPE_PTR:
q = req->questions[i];
default:
break;
}
}
if (!q) {
log_info(LD_APP, "None of the questions we got were ones we're willing "
"to support. Sending error.");
evdns_server_request_respond(req, DNS_ERR_NOTIMPL);
return;
}
if (q->type == EVDNS_TYPE_A) {
if (hostname_is_noconnect_address(q->name)) {
err = DNS_ERR_REFUSED;
}
} else {
tor_assert(q->type == EVDNS_TYPE_PTR);
}
if (err == DNS_ERR_NONE && strlen(q->name) > MAX_SOCKS_ADDR_LEN-1)
err = DNS_ERR_FORMAT;
if (err != DNS_ERR_NONE) {
evdns_server_request_respond(req, err);
return;
}
/* XXXX020 Handle .onion and .exit. */
/* XXXX020 Send a stream event to the controller. */
conn = TO_EDGE_CONN(connection_new(CONN_TYPE_AP));
if (q->type == EVDNS_TYPE_A)
conn->socks_request->command = SOCKS_COMMAND_RESOLVE;
else
conn->socks_request->command = SOCKS_COMMAND_RESOLVE_PTR;
strlcpy(conn->socks_request->address, q->name,
sizeof(conn->socks_request->address));
conn->dns_server_request = req;
/* XXXX need to set state ?? */
log_info(LD_APP, "Passing request for %s to rewrite_and_attach.", q->name);
connection_ap_handshake_rewrite_and_attach(conn, NULL, NULL);
/* Now the connection is marked if it was bad. */
log_info(LD_APP, "Passed request for %s to rewrite_and_attach.", q->name);
}
void
dnsserv_reject_request(edge_connection_t *conn)
{
evdns_server_request_respond(conn->dns_server_request, DNS_ERR_SERVERFAILED);
conn->dns_server_request = NULL;
}
void
dnsserv_resolved(edge_connection_t *conn,
int answer_type,
size_t answer_len,
const char *answer,
int ttl)
{
struct evdns_server_request *req = conn->dns_server_request;
int err = DNS_ERR_NONE;
if (!req)
return;
/* XXXX Re-do. */
if (ttl < 60)
ttl = 60;
if (answer_type == RESOLVED_TYPE_IPV6) {
log_info(LD_APP, "Got an IPv6 answer; that's not implemented.");
err = DNS_ERR_NOTIMPL;
} else if (answer_type == RESOLVED_TYPE_IPV4 && answer_len == 4 &&
conn->socks_request->command == SOCKS_COMMAND_RESOLVE) {
evdns_server_request_add_a_reply(req,
conn->socks_request->address,
1, (char*)answer, ttl);
} else if (answer_type == RESOLVED_TYPE_HOSTNAME &&
conn->socks_request->command == SOCKS_COMMAND_RESOLVE_PTR) {
char *ans = tor_strndup(answer, answer_len);
evdns_server_request_add_ptr_reply(req, NULL,
conn->socks_request->address,
(char*)answer, ttl);
tor_free(ans);
} else {
err = DNS_ERR_SERVERFAILED;
}
evdns_server_request_respond(req, err);
conn->dns_server_request = NULL;
}
void
dnsserv_configure_listener(connection_t *conn)
{
tor_assert(conn);
tor_assert(conn->s);
evdns_add_server_port(conn->s, 0, evdns_server_callback, NULL);
}
void
dnsserv_close_listener(connection_t *conn)
{
evdns_close_server_port(conn->dns_server_port);
conn->dns_server_port = NULL;
}
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