mirror of
https://github.com/rofl0r/proxychains-ng.git
synced 2024-12-22 04:08:47 +00:00
7fe8139496
since many users complain about issues with modern, ultracomplex clusterfuck software such as chromium, nodejs, etc, i've reconsidered one of my original ideas how to implement remote dns lookup support. instead of having a background thread serving requests via a pipe, the user manually starts a background daemon process before running proxychains, and the two processes then communicate via UDP. this requires much less hacks (like hooking of close() to prevent pipes from getting closed) and doesn't need to call any async-signal unsafe code like malloc(). this means it should be much more compatible than the previous method, however it's not as practical and slightly slower. it's recommended that the proxychains4-daemon runs on localhost, and if you use proxychains-ng a lot you might want to set ip up as a service that starts on boot. a single proxychains4-daemon should theoretically be able to serve many parallel proxychains4 instances, but this has not yet been tested so far. it's also possible to run the daemon on other computers, even over internet, but currently there is no error-checking/ timeout code at all; that means the UDP connection needs to be very stable. the library code used for the daemon sources are from my projects libulz[0] and htab[1], and the server code is loosely based on microsocks[2]. their licenses are all compatible with the GPL. if not otherwise mentioned, they're released for this purpose under the standard proxychains-ng license (see COPYING). [0]: https://github.com/rofl0r/libulz [1]: https://github.com/rofl0r/htab [2]: https://github.com/rofl0r/microsocks
100 lines
2.4 KiB
C
100 lines
2.4 KiB
C
#include <sys/socket.h>
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#include <stdlib.h>
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#include <string.h>
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#include "rdns.h"
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#include "allocator_thread.h"
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#include "remotedns.h"
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#ifndef HAVE_SOCK_CLOEXEC
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#define SOCK_CLOEXEC 0
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#endif
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//static enum dns_lookup_flavor dns_flavor;
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#define dns_flavor rdns_get_flavor()
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static struct sockaddr_in rdns_server;
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size_t rdns_daemon_get_host_for_ip(ip_type4 ip, char* readbuf) {
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struct at_msg msg = {
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.h.msgtype = ATM_GETNAME,
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.h.datalen = htons(4),
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.m.ip = ip,
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};
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int fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);
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sendto(fd, &msg, sizeof(msg.h)+4, 0, (void*)&rdns_server, sizeof(rdns_server));
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recvfrom(fd, &msg, sizeof msg, 0, (void*)0, (void*)0);
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close(fd);
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msg.h.datalen = ntohs(msg.h.datalen);
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if(!msg.h.datalen || msg.h.datalen > 256) return 0;
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memcpy(readbuf, msg.m.host, msg.h.datalen);
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return msg.h.datalen - 1;
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}
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static ip_type4 rdns_daemon_get_ip_for_host(char* host, size_t len) {
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struct at_msg msg = {
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.h.msgtype = ATM_GETIP,
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};
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if(len >= 256) return IPT4_INT(-1);
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memcpy(msg.m.host, host, len+1);
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msg.h.datalen = htons(len+1);
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int fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);
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sendto(fd, &msg, sizeof(msg.h)+len+1, 0, (void*)&rdns_server, sizeof(rdns_server));
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recvfrom(fd, &msg, sizeof msg, 0, (void*)0, (void*)0);
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close(fd);
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if(ntohs(msg.h.datalen) != 4) return IPT4_INT(-1);
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return msg.m.ip;
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}
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const char *rdns_resolver_string(enum dns_lookup_flavor flavor) {
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static const char tab[][7] = {
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[DNSLF_LIBC] = "off",
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[DNSLF_FORKEXEC] = "old",
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[DNSLF_RDNS_THREAD] = "thread",
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[DNSLF_RDNS_DAEMON] = "daemon",
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};
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return tab[flavor];
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}
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void rdns_init(enum dns_lookup_flavor flavor) {
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static int init_done = 0;
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if(!init_done) switch(flavor) {
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case DNSLF_RDNS_THREAD:
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at_init();
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break;
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case DNSLF_RDNS_DAEMON:
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default:
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break;
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}
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init_done = 1;
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}
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void rdns_set_daemon(struct sockaddr_in* addr) {
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rdns_server = *addr;
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}
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#if 0
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enum dns_lookup_flavor rdns_get_flavor(void) {
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return dns_flavor;
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}
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#endif
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size_t rdns_get_host_for_ip(ip_type4 ip, char* readbuf) {
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switch(dns_flavor) {
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case DNSLF_RDNS_THREAD: return at_get_host_for_ip(ip, readbuf);
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case DNSLF_RDNS_DAEMON: return rdns_daemon_get_host_for_ip(ip, readbuf);
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default:
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abort();
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}
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}
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ip_type4 rdns_get_ip_for_host(char* host, size_t len) {
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switch(dns_flavor) {
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case DNSLF_RDNS_THREAD: return at_get_ip_for_host(host, len);
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case DNSLF_RDNS_DAEMON: return rdns_daemon_get_ip_for_host(host, len);
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default:
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abort();
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}
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}
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