experimental new feature: proxy_dns_daemon

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

Makefile

@@ -13,13 +13,18 @@ includedir = $(prefix)/include
 libdir = $(prefix)/lib
 sysconfdir=$(prefix)/etc
 
-SRCS = $(sort $(wildcard src/*.c))
+OBJS = src/common.o src/main.o
-OBJS = $(SRCS:.c=.o)
+
+DOBJS = src/daemon/hsearch.o \
+        src/daemon/sblist.o src/daemon/sblist_delete.o \
+        src/daemon/daemon.o src/daemon/udpserver.o
+
 LOBJS = src/nameinfo.o src/version.o \
         src/core.o src/common.o src/libproxychains.o \
-        src/allocator_thread.o \
+        src/allocator_thread.o src/rdns.o \
         src/hostsreader.o src/hash.o src/debug.o
 
+
 GENH = src/version.h
 
 CFLAGS  += -Wall -O0 -g -std=c99 -D_GNU_SOURCE -pipe
@@ -41,7 +46,8 @@ LDSO_PATHNAME = libproxychains4.$(LDSO_SUFFIX)
 SHARED_LIBS = $(LDSO_PATHNAME)
 ALL_LIBS = $(SHARED_LIBS)
 PXCHAINS = proxychains4
-ALL_TOOLS = $(PXCHAINS)
+PXCHAINS_D = proxychains4-daemon
+ALL_TOOLS = $(PXCHAINS) $(PXCHAINS_D)
 ALL_CONFIGS = src/proxychains.conf
 
 -include config.mak
@@ -70,7 +76,7 @@ install-config: $(ALL_CONFIGS:src/%=$(DESTDIR)$(sysconfdir)/%)
 clean:
 	rm -f $(ALL_LIBS)
 	rm -f $(ALL_TOOLS)
-	rm -f $(OBJS)
+	rm -f $(OBJS) $(LOBJS) $(DOBJS)
 	rm -f $(GENH)
 
 src/version.h: $(wildcard VERSION .git)
@@ -83,10 +89,13 @@ src/version.o: src/version.h
 
 $(LDSO_PATHNAME): $(LOBJS)
 	$(CC) $(LDFLAGS) $(LD_SET_SONAME)$(LDSO_PATHNAME) $(USER_LDFLAGS) \
-		-shared -o $@ $(LOBJS) $(SOCKET_LIBS)
+		-shared -o $@ $^ $(SOCKET_LIBS)
 
-$(ALL_TOOLS): $(OBJS)
+$(PXCHAINS): $(OBJS)
-	$(CC) src/main.o src/common.o $(USER_LDFLAGS) $(LIBDL) -o $(PXCHAINS)
+	$(CC) $^ $(USER_LDFLAGS) $(LIBDL) -o $@
+
+$(PXCHAINS_D): $(DOBJS)
+	$(CC) $^ $(USER_LDFLAGS) -o $@
 
 
 .PHONY: all clean install install-config install-libs install-tools

configure

@@ -159,6 +159,9 @@ check_compile 'whether we have GNU-style getservbyname_r()' "-DHAVE_GNU_GETSERVB
 check_compile 'whether we have pipe2() and O_CLOEXEC' "-DHAVE_PIPE2" \
 '#define _GNU_SOURCE\n#include <fcntl.h>\n#include <unistd.h>\nint main() {\nint pipefd[2];\npipe2(pipefd, O_CLOEXEC);\nreturn 0;}'
 
+check_compile 'whether we have SOCK_CLOEXEC' "-DHAVE_SOCK_CLOEXEC" \
+'#define _GNU_SOURCE\n#include <sys/socket.h>\nint main() {\nreturn socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);}'
+
 check_define __APPLE__ && {
 	mac_detected=true
 	check_define __x86_64__ && mac_64=true

src/allocator_thread.h

@@ -4,8 +4,6 @@
 #include <unistd.h>
 #include "ip_type.h"
 
-#define MSG_LEN_MAX 256
-
 extern int req_pipefd[2];
 extern int resp_pipefd[2];
 

src/core.c

@@ -37,13 +37,12 @@
 
 #include "core.h"
 #include "common.h"
-#include "allocator_thread.h"
+#include "rdns.h"
 #include "mutex.h"
 
 extern int tcp_read_time_out;
 extern int tcp_connect_time_out;
 extern int proxychains_quiet_mode;
-extern int proxychains_resolver;
 extern unsigned int proxychains_proxy_offset;
 extern unsigned int remote_dns_subnet;
 
@@ -200,8 +199,8 @@ static int tunnel_to(int sock, ip_type ip, unsigned short port, proxy_type pt, c
 	// the range 224-255.* is reserved, and it won't go outside (unless the app does some other stuff with
 	// the results returned from gethostbyname et al.)
 	// the hardcoded number 224 can now be changed using the config option remote_dns_subnet to i.e. 127
-	if(!ip.is_v6 && proxychains_resolver && ip.addr.v4.octet[0] == remote_dns_subnet) {
+	if(!ip.is_v6 && proxychains_resolver >= DNSLF_RDNS_START && ip.addr.v4.octet[0] == remote_dns_subnet) {
-		dns_len = at_get_host_for_ip(ip.addr.v4, hostnamebuf);
+		dns_len = rdns_get_host_for_ip(ip.addr.v4, hostnamebuf);
 		if(!dns_len) goto err;
 		else dns_name = hostnamebuf;
 	}
@@ -525,8 +524,8 @@ static int chain_step(int ns, proxy_data * pfrom, proxy_data * pto) {
 
 	PFUNC();
 
-	if(!v6 && proxychains_resolver && pto->ip.addr.v4.octet[0] == remote_dns_subnet) {
+	if(!v6 && proxychains_resolver >= DNSLF_RDNS_START && pto->ip.addr.v4.octet[0] == remote_dns_subnet) {
-		if(!at_get_host_for_ip(pto->ip.addr.v4, hostname_buf)) goto usenumericip;
+		if(!rdns_get_host_for_ip(pto->ip.addr.v4, hostname_buf)) goto usenumericip;
 		else hostname = hostname_buf;
 	} else {
 	usenumericip:
@@ -865,7 +864,7 @@ struct hostent *proxy_gethostbyname(const char *name, struct gethostbyname_data*
 		goto retname;
 	}
 	
-	data->resolved_addr = at_get_ip_for_host((char*) name, strlen(name)).as_int;
+	data->resolved_addr = rdns_get_ip_for_host((char*) name, strlen(name)).as_int;
 	if(data->resolved_addr == (in_addr_t) IPT4_INVALID.as_int) return NULL;
 
 	retname:
@@ -961,7 +960,7 @@ int proxy_getaddrinfo(const char *node, const char *service, const struct addrin
 			free(space);
 			return EAI_NONAME;
 		}
-		if(proxychains_resolver == 2)
+		if(proxychains_resolver == DNSLF_FORKEXEC)
 			hp = proxy_gethostbyname_old(node);
 		else
 			hp = proxy_gethostbyname(node, &ghdata);

src/daemon/daemon.c

@@ -0,0 +1,231 @@
+/*
+   proxychains-ng DNS daemon
+
+   Copyright (C) 2020 rofl0r.
+
+*/
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#define _POSIX_C_SOURCE 200809L
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <signal.h>
+#include <sys/select.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <limits.h>
+#include "udpserver.h"
+#include "sblist.h"
+#include "hsearch.h"
+#include "../remotedns.h"
+#include "../ip_type.h"
+
+#ifndef MAX
+#define MAX(x, y) ((x) > (y) ? (x) : (y))
+#endif
+
+static struct htab *ip_lookup_table;
+static sblist *hostnames;
+static unsigned remote_subnet;
+static const struct server* server;
+
+#ifndef CONFIG_LOG
+#define CONFIG_LOG 1
+#endif
+#if CONFIG_LOG
+/* we log to stderr because it's not using line buffering, i.e. malloc which would need
+   locking when called from different threads. for the same reason we use dprintf,
+   which writes directly to an fd. */
+#define dolog(...) dprintf(2, __VA_ARGS__)
+#else
+static void dolog(const char* fmt, ...) { }
+#endif
+
+static char* my_inet_ntoa(unsigned char *ip_buf_4_bytes, char *outbuf_16_bytes) {
+	unsigned char *p;
+	char *o = outbuf_16_bytes;
+	unsigned char n;
+	for(p = ip_buf_4_bytes; p < ip_buf_4_bytes + 4; p++) {
+		n = *p;
+		if(*p >= 100) {
+			if(*p >= 200)
+				*(o++) = '2';
+			else
+				*(o++) = '1';
+			n %= 100;
+		}
+		if(*p >= 10) {
+			*(o++) = (n / 10) + '0';
+			n %= 10;
+		}
+		*(o++) = n + '0';
+		*(o++) = '.';
+	}
+	o[-1] = 0;
+	return outbuf_16_bytes;
+}
+
+
+/* buf needs to be long enough for an ipv6 addr, i.e. INET6_ADDRSTRLEN + 1 */
+static char* ipstr(union sockaddr_union *su, char* buf) {
+	int af = SOCKADDR_UNION_AF(su);
+	void *ipdata = SOCKADDR_UNION_ADDRESS(su);
+	inet_ntop(af, ipdata, buf, INET6_ADDRSTRLEN+1);
+	char portbuf[7];
+	snprintf(portbuf, sizeof portbuf, ":%u", (unsigned) ntohs(SOCKADDR_UNION_PORT(su)));
+	strcat(buf, portbuf);
+	return buf;
+}
+
+static int usage(char *a0) {
+	dprintf(2,
+		"Proxychains-NG remote dns daemon\n"
+		"--------------------------------\n"
+		"usage: %s -i listenip -p port -r remotesubnet\n"
+		"all arguments are optional.\n"
+		"by default listenip is 127.0.0.1, port 1053 and remotesubnet 224.\n\n", a0
+	);
+	return 1;
+}
+
+unsigned index_from_ip(ip_type4 internalip) {
+	ip_type4 tmp = internalip;
+	uint32_t ret;
+	ret = tmp.octet[3] + (tmp.octet[2] << 8) + (tmp.octet[1] << 16);
+	ret -= 1;
+	return ret;
+}
+
+char *host_from_ip(ip_type4 internalip) {
+	char *res = NULL;
+	unsigned index = index_from_ip(internalip);
+	if(index < sblist_getsize(hostnames)) {
+		char **tmp = sblist_get(hostnames, index);
+		if(tmp && *tmp) res = *tmp;
+	}
+	return res;
+}
+
+ip_type4 get_ip_from_index(unsigned index) {
+	ip_type4 ret;
+	index++; // so we can start at .0.0.1
+	if(index > 0xFFFFFF)
+		return IPT4_INVALID;
+	ret.octet[0] = remote_subnet & 0xFF;
+	ret.octet[1] = (index & 0xFF0000) >> 16;
+	ret.octet[2] = (index & 0xFF00) >> 8;
+	ret.octet[3] = index & 0xFF;
+	return ret;
+}
+
+ip_type4 get_ip(char* hn) {
+	htab_value *v = htab_find(ip_lookup_table, hn);
+	if(v) return get_ip_from_index(v->n);
+	char *n = strdup(hn);
+	if(!n) return IPT4_INVALID;
+	if(!sblist_add(hostnames, &n)) {
+	o_out:;
+		free(n);
+		return IPT4_INVALID;
+	}
+	if(!htab_insert(ip_lookup_table, n, HTV_N(sblist_getsize(hostnames)-1))) {
+		sblist_delete(hostnames, sblist_getsize(hostnames)-1);
+		goto o_out;
+	}
+	return get_ip_from_index(sblist_getsize(hostnames)-1);
+}
+
+int main(int argc, char** argv) {
+	int ch;
+	const char *listenip = "127.0.0.1";
+	unsigned port = 1053;
+	remote_subnet = 224;
+	while((ch = getopt(argc, argv, ":r:i:p:")) != -1) {
+		switch(ch) {
+			case 'r':
+				remote_subnet = atoi(optarg);
+				break;
+			case 'i':
+				listenip = optarg;
+				break;
+			case 'p':
+				port = atoi(optarg);
+				break;
+			case ':':
+				dprintf(2, "error: option -%c requires an operand\n", optopt);
+				/* fall through */
+			case '?':
+				return usage(argv[0]);
+		}
+	}
+	signal(SIGPIPE, SIG_IGN);
+	struct server s;
+	if(server_setup(&s, listenip, port)) {
+		perror("server_setup");
+		return 1;
+	}
+	server = &s;
+
+	ip_lookup_table = htab_create(64);
+	hostnames = sblist_new(sizeof(char*), 64);
+
+	while(1) {
+		struct client c;
+		char ipstr_buf[INET6_ADDRSTRLEN+6+1];
+		char ip4str_buf[16];
+		struct at_msg msg, out;
+		size_t msgl = sizeof(msg);
+		int failed = 0;
+
+#define FAIL() do { failed=1; goto sendresp; } while(0)
+
+		if(server_waitclient(&s, &c, &msg, &msgl)) continue;
+		msg.h.datalen = ntohs(msg.h.datalen);
+		if(msgl != sizeof(msg.h)+msg.h.datalen) {
+			dolog("%s: invalid datalen\n", ipstr(&c.addr, ipstr_buf));
+			FAIL();
+		}
+
+		out.h.msgtype = msg.h.msgtype;
+		if(msg.h.msgtype == ATM_GETIP) {
+			if(!memchr(msg.m.host, 0, msg.h.datalen)) {
+				dolog("%s: nul terminator missing\n", ipstr(&c.addr, ipstr_buf));
+				FAIL();
+			}
+			out.h.datalen = sizeof(ip_type4);
+			out.m.ip = get_ip(msg.m.host);
+			failed = !memcmp(&out.m.ip, &IPT4_INVALID, 4);
+			dolog("%s requested ip for %s (%s)\n", ipstr(&c.addr, ipstr_buf),
+			      msg.m.host, failed?"FAIL":my_inet_ntoa((void*)&out.m.ip, ip4str_buf));
+			if(failed) FAIL();
+		} else if (msg.h.msgtype == ATM_GETNAME) {
+			if(msg.h.datalen != 4) {
+				dolog("%s: invalid len for getname request\n", ipstr(&c.addr, ipstr_buf));
+				FAIL();
+			}
+			char *hn = host_from_ip(msg.m.ip);
+			if(hn) {
+				size_t l = strlen(hn);
+				memcpy(out.m.host, hn, l+1);
+				out.h.datalen = l+1;
+			}
+			dolog("%s requested name for %s (%s)\n", ipstr(&c.addr, ipstr_buf),
+			      my_inet_ntoa((void*) &msg.m.ip, ip4str_buf), hn?hn:"FAIL");
+			if(!hn) FAIL();
+		} else {
+			dolog("%s: unknown request %u\n", ipstr(&c.addr, ipstr_buf),
+			      (unsigned) msg.h.msgtype);
+		}
+	sendresp:;
+		if(failed) {
+			out.h.msgtype = ATM_FAIL;
+			out.h.datalen = 0;
+		}
+		unsigned short dlen = out.h.datalen;
+		out.h.datalen = htons(dlen);
+		sendto(server->fd, &out, sizeof(out.h)+dlen, 0, (void*) &c.addr, SOCKADDR_UNION_LENGTH(&c.addr));
+	}
+}

src/daemon/hsearch.c

@@ -0,0 +1,188 @@
+/*
+musl license, hsearch.c originally written by Szabolcs Nagy
+
+Copyright © 2005-2020 Rich Felker, et al.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#include <stdlib.h>
+#include <string.h>
+#include "hsearch.h"
+
+/*
+open addressing hash table with 2^n table size
+quadratic probing is used in case of hash collision
+tab indices and hash are size_t
+after resize fails with ENOMEM the state of tab is still usable
+*/
+
+typedef struct htab_entry {
+	char *key;
+	htab_value data;
+} htab_entry;
+
+struct elem {
+	htab_entry item;
+	size_t hash;
+};
+
+struct htab {
+	struct elem *elems;
+	size_t mask;
+	size_t used;
+};
+
+#define MINSIZE 8
+#define MAXSIZE ((size_t)-1/2 + 1)
+
+static size_t keyhash(char *k)
+{
+	unsigned char *p = (void *)k;
+	size_t h = 0;
+
+	while (*p)
+		h = 31*h + *p++;
+	return h;
+}
+
+static int resize(struct htab *htab, size_t nel)
+{
+	size_t newsize;
+	size_t i, j;
+	struct elem *e, *newe;
+	struct elem *oldtab = htab->elems;
+	struct elem *oldend = htab->elems + htab->mask + 1;
+
+	if (nel > MAXSIZE)
+		nel = MAXSIZE;
+	for (newsize = MINSIZE; newsize < nel; newsize *= 2);
+	htab->elems = calloc(newsize, sizeof *htab->elems);
+	if (!htab->elems) {
+		htab->elems = oldtab;
+		return 0;
+	}
+	htab->mask = newsize - 1;
+	if (!oldtab)
+		return 1;
+	for (e = oldtab; e < oldend; e++)
+		if (e->item.key) {
+			for (i=e->hash,j=1; ; i+=j++) {
+				newe = htab->elems + (i & htab->mask);
+				if (!newe->item.key)
+					break;
+			}
+			*newe = *e;
+		}
+	free(oldtab);
+	return 1;
+}
+
+static struct elem *lookup(struct htab *htab, char *key, size_t hash)
+{
+	size_t i, j;
+	struct elem *e;
+
+	for (i=hash,j=1; ; i+=j++) {
+		e = htab->elems + (i & htab->mask);
+		if (!e->item.key ||
+		    (e->hash==hash && strcmp(e->item.key, key)==0))
+			break;
+	}
+	return e;
+}
+
+struct htab *htab_create(size_t nel)
+{
+	struct htab *r = calloc(1, sizeof *r);
+	if(r && !resize(r, nel)) {
+		free(r);
+		r = 0;
+	}
+	return r;
+}
+
+void htab_destroy(struct htab *htab)
+{
+	free(htab->elems);
+	free(htab);
+}
+
+static htab_entry *htab_find_item(struct htab *htab, char* key)
+{
+	size_t hash = keyhash(key);
+	struct elem *e = lookup(htab, key, hash);
+
+	if (e->item.key) {
+		return &e->item;
+	}
+	return 0;
+}
+
+htab_value* htab_find(struct htab *htab, char* key)
+{
+	htab_entry *i = htab_find_item(htab, key);
+	if(i) return &i->data;
+	return 0;
+}
+
+int htab_delete(struct htab *htab, char* key)
+{
+	htab_entry *i = htab_find_item(htab, key);
+	if(!i) return 0;
+	i->key = 0;
+	return 1;
+}
+
+int htab_insert(struct htab *htab, char* key, htab_value value)
+{
+	size_t hash = keyhash(key);
+	struct elem *e = lookup(htab, key, hash);
+	if(e->item.key) {
+		/* it's not allowed to overwrite existing data */
+		return 0;
+	}
+
+	e->item.key = key;
+	e->item.data = value;
+	e->hash = hash;
+	if (++htab->used > htab->mask - htab->mask/4) {
+		if (!resize(htab, 2*htab->used)) {
+			htab->used--;
+			e->item.key = 0;
+			return 0;
+		}
+	}
+	return 1;
+}
+
+size_t htab_next(struct htab *htab, size_t iterator, char** key, htab_value **v)
+{
+	size_t i;
+	for(i=iterator;i<htab->mask+1;++i) {
+		struct elem *e = htab->elems + i;
+		if(e->item.key) {
+			*key = e->item.key;
+			*v = &e->item.data;
+			return i+1;
+		}
+	}
+	return 0;
+}

src/daemon/hsearch.h

@@ -0,0 +1,21 @@
+#ifndef HSEARCH_H
+#define HSEARCH_H
+
+#include <stdlib.h>
+
+typedef union htab_value {
+	void *p;
+	size_t n;
+} htab_value;
+
+#define HTV_N(N) (htab_value) {.n = N}
+#define HTV_P(P) (htab_value) {.p = P}
+
+struct htab * htab_create(size_t);
+void htab_destroy(struct htab *);
+htab_value* htab_find(struct htab *, char* key);
+int htab_insert(struct htab *, char*, htab_value);
+int htab_delete(struct htab *htab, char* key);
+size_t htab_next(struct htab *, size_t iterator, char** key, htab_value **v);
+
+#endif

src/daemon/sblist.c

@@ -0,0 +1,73 @@
+#undef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+#include "sblist.h"
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#define MY_PAGE_SIZE 4096
+
+sblist* sblist_new(size_t itemsize, size_t blockitems) {
+	sblist* ret = (sblist*) malloc(sizeof(sblist));
+	sblist_init(ret, itemsize, blockitems);
+	return ret;
+}
+
+static void sblist_clear(sblist* l) {
+	l->items = NULL;
+	l->capa = 0;
+	l->count = 0;
+}
+
+void sblist_init(sblist* l, size_t itemsize, size_t blockitems) {
+	if(l) {
+		l->blockitems = blockitems ? blockitems : MY_PAGE_SIZE / itemsize;
+		l->itemsize = itemsize;
+		sblist_clear(l);
+	}
+}
+
+void sblist_free_items(sblist* l) {
+	if(l) {
+		if(l->items) free(l->items);
+		sblist_clear(l);
+	}
+}
+
+void sblist_free(sblist* l) {
+	if(l) {
+		sblist_free_items(l);
+		free(l);
+	}
+}
+
+char* sblist_item_from_index(sblist* l, size_t idx) {
+	return l->items + (idx * l->itemsize);
+}
+
+void* sblist_get(sblist* l, size_t item) {
+	if(item < l->count) return (void*) sblist_item_from_index(l, item);
+	return NULL;
+}
+
+int sblist_set(sblist* l, void* item, size_t pos) {
+	if(pos >= l->count) return 0;
+	memcpy(sblist_item_from_index(l, pos), item, l->itemsize);
+	return 1;
+}
+
+int sblist_grow_if_needed(sblist* l) {
+	char* temp;
+	if(l->count == l->capa) {
+		temp = realloc(l->items, (l->capa + l->blockitems) * l->itemsize);
+		if(!temp) return 0;
+		l->capa += l->blockitems;
+		l->items = temp;
+	}
+	return 1;
+}
+
+int sblist_add(sblist* l, void* item) {
+	if(!sblist_grow_if_needed(l)) return 0;
+	l->count++;
+	return sblist_set(l, item, l->count - 1);
+}

src/daemon/sblist.h

@@ -0,0 +1,92 @@
+#ifndef SBLIST_H
+#define SBLIST_H
+
+/* this file is part of libulz, as of commit 8ab361a27743aaf025323ee43b8b8876dc054fdd
+   modified for direct inclusion in microsocks. */
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>
+/*
+ * simple buffer list.
+ * 
+ * this thing here is basically a generic dynamic array
+ * will realloc after every blockitems inserts
+ * can store items of any size.
+ * 
+ * so think of it as a by-value list, as opposed to a typical by-ref list.
+ * you typically use it by having some struct on the stack, and pass a pointer
+ * to sblist_add, which will copy the contents into its internal memory.
+ * 
+ */
+
+typedef struct {
+	size_t itemsize;
+	size_t blockitems;
+	size_t count;
+	size_t capa;
+	char* items;
+} sblist;
+
+#define sblist_getsize(X) ((X)->count)
+#define sblist_get_count(X) ((X)->count)
+#define sblist_empty(X) ((X)->count == 0)
+
+// for dynamic style
+sblist* sblist_new(size_t itemsize, size_t blockitems);
+void sblist_free(sblist* l);
+
+//for static style
+void sblist_init(sblist* l, size_t itemsize, size_t blockitems);
+void sblist_free_items(sblist* l);
+
+// accessors
+void* sblist_get(sblist* l, size_t item);
+// returns 1 on success, 0 on OOM
+int sblist_add(sblist* l, void* item);
+int sblist_set(sblist* l, void* item, size_t pos);
+void sblist_delete(sblist* l, size_t item);
+char* sblist_item_from_index(sblist* l, size_t idx);
+int sblist_grow_if_needed(sblist* l);
+int sblist_insert(sblist* l, void* item, size_t pos);
+/* same as sblist_add, but returns list index of new item, or -1 */
+size_t sblist_addi(sblist* l, void* item);
+void sblist_sort(sblist *l, int (*compar)(const void *, const void *));
+/* insert element into presorted list, returns listindex of new entry or -1*/
+size_t sblist_insert_sorted(sblist* l, void* o, int (*compar)(const void *, const void *));
+
+#ifndef __COUNTER__
+#define __COUNTER__ __LINE__
+#endif
+
+#define __sblist_concat_impl( x, y ) x##y
+#define __sblist_macro_concat( x, y ) __sblist_concat_impl( x, y )
+#define __sblist_iterator_name __sblist_macro_concat(sblist_iterator, __COUNTER__)
+
+// use with custom iterator variable
+#define sblist_iter_counter(LIST, ITER, PTR) \
+	for(size_t ITER = 0; (PTR = sblist_get(LIST, ITER)), ITER < sblist_getsize(LIST); ITER++)
+
+// use with custom iterator variable, which is predeclared
+#define sblist_iter_counter2(LIST, ITER, PTR) \
+	for(ITER = 0; (PTR = sblist_get(LIST, ITER)), ITER < sblist_getsize(LIST); ITER++)
+
+// use with custom iterator variable, which is predeclared and signed
+// useful for a loop which can delete items from the list, and then decrease the iterator var.
+#define sblist_iter_counter2s(LIST, ITER, PTR) \
+	for(ITER = 0; (PTR = sblist_get(LIST, ITER)), ITER < (ssize_t) sblist_getsize(LIST); ITER++)
+
+
+// uses "magic" iterator variable
+#define sblist_iter(LIST, PTR) sblist_iter_counter(LIST, __sblist_iterator_name, PTR)
+
+#ifdef __cplusplus
+}
+#endif
+
+#pragma RcB2 DEP "sblist.c" "sblist_delete.c"
+
+#endif

src/daemon/sblist_delete.c

@@ -0,0 +1,9 @@
+#include "sblist.h"
+#include <string.h>
+
+void sblist_delete(sblist* l, size_t item) {
+	if (l->count && item < l->count) {
+		memmove(sblist_item_from_index(l, item), sblist_item_from_index(l, item + 1), (sblist_getsize(l) - (item + 1)) * l->itemsize);
+		l->count--;
+	}
+}

src/daemon/udpclient.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include "../remotedns.h"
+#include "../ip_type.h"
+
+int main() {
+	int fd;
+	int port = 1053;
+	char srvn[] = "127.0.0.1";
+	struct sockaddr_in srva = {.sin_family = AF_INET, .sin_port = htons(port)};
+	inet_pton(AF_INET, srvn, &srva.sin_addr);
+	fd = socket(AF_INET, SOCK_DGRAM, 0);
+	char namebuf[260];
+	while(fgets(namebuf, sizeof namebuf, stdin)) {
+		size_t l = strlen(namebuf);
+		if(namebuf[l-1] == '\n') {
+			l--;
+			namebuf[l] = 0;
+		}
+		struct at_msg msg = {0};
+		unsigned msglen;
+		if(isdigit(namebuf[0])) {
+			msglen = 4;
+			msg.h.msgtype = ATM_GETNAME;
+			inet_aton(namebuf, (void*) &msg.m.ip);
+		} else {
+			msglen = l+1;
+			msg.h.msgtype = ATM_GETIP;
+			memcpy(msg.m.host, namebuf, msglen);
+		}
+		msg.h.datalen = htons(msglen);
+		sendto(fd, &msg, sizeof(msg.h)+msglen, 0, (void*)&srva, sizeof(srva));
+		char rcvbuf[512];
+		recvfrom(fd, rcvbuf, sizeof rcvbuf, 0, (void*)0, (void*)0);
+	}
+}

src/daemon/udpserver.c

@@ -0,0 +1,65 @@
+#include "udpserver.h"
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+int resolve(const char *host, unsigned short port, struct addrinfo** addr) {
+	struct addrinfo hints = {
+		.ai_family = AF_UNSPEC,
+		.ai_socktype = SOCK_STREAM,
+		.ai_flags = AI_PASSIVE,
+	};
+	char port_buf[8];
+	snprintf(port_buf, sizeof port_buf, "%u", port);
+	return getaddrinfo(host, port_buf, &hints, addr);
+}
+
+int resolve_sa(const char *host, unsigned short port, union sockaddr_union *res) {
+	struct addrinfo *ainfo = 0;
+	int ret;
+	SOCKADDR_UNION_AF(res) = AF_UNSPEC;
+	if((ret = resolve(host, port, &ainfo))) return ret;
+	memcpy(res, ainfo->ai_addr, ainfo->ai_addrlen);
+	freeaddrinfo(ainfo);
+	return 0;
+}
+
+int bindtoip(int fd, union sockaddr_union *bindaddr) {
+	socklen_t sz = SOCKADDR_UNION_LENGTH(bindaddr);
+	if(sz)
+		return bind(fd, (struct sockaddr*) bindaddr, sz);
+	return 0;
+}
+
+int server_waitclient(struct server *server, struct client* client, void* buf, size_t *buflen) {
+	socklen_t clen = sizeof client->addr;
+	ssize_t ret = recvfrom(server->fd, buf, *buflen, 0, (void*)&client->addr, &clen);
+	if(ret >= 0) {
+		*buflen = ret;
+		return 0;
+	}
+	return ret;
+}
+
+int server_setup(struct server *server, const char* listenip, unsigned short port) {
+	struct addrinfo *ainfo = 0;
+	if(resolve(listenip, port, &ainfo)) return -1;
+	struct addrinfo* p;
+	int listenfd = -1;
+	for(p = ainfo; p; p = p->ai_next) {
+		if((listenfd = socket(p->ai_family, SOCK_DGRAM, 0)) < 0)
+			continue;
+		int yes = 1;
+		setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
+		if(bind(listenfd, p->ai_addr, p->ai_addrlen) < 0) {
+			close(listenfd);
+			listenfd = -1;
+			continue;
+		}
+		break;
+	}
+	freeaddrinfo(ainfo);
+	if(listenfd < 0) return -2;
+	server->fd = listenfd;
+	return 0;
+}

src/daemon/udpserver.h

@@ -0,0 +1,48 @@
+#ifndef SERVER_H
+#define SERVER_H
+
+#undef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+
+#include <sys/socket.h>
+#include <netdb.h>
+#include <netinet/in.h>
+
+#pragma RcB2 DEP "udpserver.c"
+
+union sockaddr_union {
+	struct sockaddr_in  v4;
+	struct sockaddr_in6 v6;
+};
+
+#define SOCKADDR_UNION_AF(PTR) (PTR)->v4.sin_family
+
+#define SOCKADDR_UNION_LENGTH(PTR) ( \
+	( SOCKADDR_UNION_AF(PTR) == AF_INET  ) ? sizeof((PTR)->v4) : ( \
+	( SOCKADDR_UNION_AF(PTR) == AF_INET6 ) ? sizeof((PTR)->v6) : 0 ) )
+
+#define SOCKADDR_UNION_ADDRESS(PTR) ( \
+	( SOCKADDR_UNION_AF(PTR) == AF_INET  ) ? (void*) &(PTR)->v4.sin_addr  : ( \
+	( SOCKADDR_UNION_AF(PTR) == AF_INET6 ) ? (void*) &(PTR)->v6.sin6_addr : (void*) 0 ) )
+
+#define SOCKADDR_UNION_PORT(PTR) ( \
+	( SOCKADDR_UNION_AF(PTR) == AF_INET  ) ? (PTR)->v4.sin_port  : ( \
+	( SOCKADDR_UNION_AF(PTR) == AF_INET6 ) ? (PTR)->v6.sin6_port : 0 ) )
+
+struct client {
+	union sockaddr_union addr;
+};
+
+struct server {
+	int fd;
+};
+
+int resolve(const char *host, unsigned short port, struct addrinfo** addr);
+int resolve_sa(const char *host, unsigned short port, union sockaddr_union *res);
+int bindtoip(int fd, union sockaddr_union *bindaddr);
+
+int server_waitclient(struct server *server, struct client* client, void* buf, size_t *buflen);
+int server_setup(struct server *server, const char* listenip, unsigned short port);
+
+#endif
+

src/libproxychains.c

@@ -38,6 +38,7 @@
 
 #include "core.h"
 #include "common.h"
+#include "rdns.h"
 
 #undef 		satosin
 #define     satosin(x)      ((struct sockaddr_in *) &(x))
@@ -71,7 +72,7 @@ unsigned int proxychains_proxy_offset = 0;
 int proxychains_got_chain_data = 0;
 unsigned int proxychains_max_chain = 1;
 int proxychains_quiet_mode = 0;
-int proxychains_resolver = 0;
+enum dns_lookup_flavor proxychains_resolver = DNSLF_LIBC;
 localaddr_arg localnet_addr[MAX_LOCALNET];
 size_t num_localnet_addr = 0;
 dnat_arg dnats[MAX_DNAT];
@@ -126,12 +127,6 @@ static void setup_hooks(void) {
 static int close_fds[16];
 static int close_fds_cnt = 0;
 
-static void rdns_init(void) {
-	static int init_done = 0;
-	if(!init_done) at_init();
-	init_done = 1;
-}
-
 static void do_init(void) {
 	srand(time(NULL));
 	core_initialize();
@@ -147,7 +142,7 @@ static void do_init(void) {
 	while(close_fds_cnt) true_close(close_fds[--close_fds_cnt]);
 	init_l = 1;
 
-	if(proxychains_resolver == 1) rdns_init();
+	rdns_init(proxychains_resolver);
 }
 
 static void init_lib_wrapper(const char* caller) {
@@ -281,6 +276,7 @@ static void get_chain_data(proxy_data * pd, unsigned int *proxy_count, chain_typ
 	char local_in_addr[32], local_in_port[32], local_netmask[32];
 	char dnat_orig_addr_port[32], dnat_new_addr_port[32];
 	char dnat_orig_addr[32], dnat_orig_port[32], dnat_new_addr[32], dnat_new_port[32];
+	char rdnsd_addr[32], rdnsd_port[8];
 	FILE *file = NULL;
 
 	if(proxychains_got_chain_data)
@@ -339,9 +335,9 @@ static void get_chain_data(proxy_data * pd, unsigned int *proxy_count, chain_typ
 				pd[count].port = htons((unsigned short) port_n);
 				ip_type* host_ip = &pd[count].ip;
 				if(1 != inet_pton(host_ip->is_v6 ? AF_INET6 : AF_INET, host, host_ip->addr.v6)) {
-					if(*ct == STRICT_TYPE && proxychains_resolver == 1 && count > 0) {
+					if(*ct == STRICT_TYPE && proxychains_resolver >= DNSLF_RDNS_START && count > 0) {
 						/* we can allow dns hostnames for all but the first proxy in the list if chaintype is strict, as remote lookup can be done */
-						rdns_init();
+						rdns_init(proxychains_resolver);
 						ip_type4 internal_ip = at_get_ip_for_host(host, strlen(host));
 						pd[count].ip.is_v6 = 0;
 						host_ip->addr.v4 = internal_ip;
@@ -351,7 +347,7 @@ static void get_chain_data(proxy_data * pd, unsigned int *proxy_count, chain_typ
 inv_host:
 						fprintf(stderr, "proxy %s has invalid value or is not numeric\n", host);
 						fprintf(stderr, "non-numeric ips are only allowed under the following circumstances:\n");
-						fprintf(stderr, "chaintype == strict (%s), proxy is not first in list (%s), proxy_dns active (%s)\n\n", bool_str(*ct == STRICT_TYPE), bool_str(count > 0), bool_str(proxychains_resolver));
+						fprintf(stderr, "chaintype == strict (%s), proxy is not first in list (%s), proxy_dns active (%s)\n\n", bool_str(*ct == STRICT_TYPE), bool_str(count > 0), rdns_resolver_string(proxychains_resolver));
 						exit(1);
 					}
 				}
@@ -443,9 +439,25 @@ inv_host:
 				} else if(!strcmp(buff, "quiet_mode")) {
 					proxychains_quiet_mode = 1;
 				} else if(!strcmp(buff, "proxy_dns_old")) {
-					proxychains_resolver = 2;
+					proxychains_resolver = DNSLF_FORKEXEC;
 				} else if(!strcmp(buff, "proxy_dns")) {
-					proxychains_resolver = 1;
+					proxychains_resolver = DNSLF_RDNS_THREAD;
+				} else if(STR_STARTSWITH(buff, "proxy_dns_daemon")) {
+					struct sockaddr_in rdns_server_buffer;
+
+					if(sscanf(buff, "%s %15[^:]:%5s", user, rdnsd_addr, rdnsd_port) < 3) {
+						fprintf(stderr, "proxy_dns_daemon format error\n");
+						exit(1);
+					}
+					rdns_server_buffer.sin_family = AF_INET;
+					int error = inet_pton(AF_INET, rdnsd_addr, &rdns_server_buffer.sin_addr);
+					if(error <= 0) {
+						fprintf(stderr, "bogus proxy_dns_daemon address\n");
+						exit(1);
+					}
+					rdns_server_buffer.sin_port = htons(atoi(rdnsd_port));
+					proxychains_resolver = DNSLF_RDNS_DAEMON;
+					rdns_set_daemon(&rdns_server_buffer);
 				} else if(STR_STARTSWITH(buff, "dnat")) {
 					if(sscanf(buff, "%s %21[^ ] %21s\n", user, dnat_orig_addr_port, dnat_new_addr_port) < 3) {
 						fprintf(stderr, "dnat format error");
@@ -508,7 +520,7 @@ inv_host:
 	}
 	*proxy_count = count;
 	proxychains_got_chain_data = 1;
-	PDEBUG("proxy_dns: %s\n", proxychains_resolver ? (proxychains_resolver == 2 ? "OLD" : "ON") : "OFF");
+	PDEBUG("proxy_dns: %s\n", rdns_resolver_string(proxychains_resolver));
 }
 
 /*******  HOOK FUNCTIONS  *******/
@@ -520,7 +532,7 @@ int close(int fd) {
 		errno = 0;
 		return 0;
 	}
-	if(proxychains_resolver != 1) return true_close(fd);
+	if(proxychains_resolver != DNSLF_RDNS_THREAD) return true_close(fd);
 
 	/* prevent rude programs (like ssh) from closing our pipes */
 	if(fd != req_pipefd[0]  && fd != req_pipefd[1] &&
@@ -635,12 +647,12 @@ struct hostent *gethostbyname(const char *name) {
 	INIT();
 	PDEBUG("gethostbyname: %s\n", name);
 
-	if(proxychains_resolver == 1)
+	if(proxychains_resolver == DNSLF_FORKEXEC)
-		return proxy_gethostbyname(name, &ghbndata);
-	else if(proxychains_resolver == 2)
 		return proxy_gethostbyname_old(name);
-	else
+	else if(proxychains_resolver == DNSLF_LIBC)
 		return true_gethostbyname(name);
+	else
+		return proxy_gethostbyname(name, &ghbndata);
 
 	return NULL;
 }
@@ -649,7 +661,7 @@ int getaddrinfo(const char *node, const char *service, const struct addrinfo *hi
 	INIT();
 	PDEBUG("getaddrinfo: %s %s\n", node ? node : "null", service ? service : "null");
 
-	if(proxychains_resolver)
+	if(proxychains_resolver != DNSLF_LIBC)
 		return proxy_getaddrinfo(node, service, hints, res);
 	else
 		return true_getaddrinfo(node, service, hints, res);
@@ -659,7 +671,7 @@ void freeaddrinfo(struct addrinfo *res) {
 	INIT();
 	PDEBUG("freeaddrinfo %p \n", (void *) res);
 
-	if(!proxychains_resolver)
+	if(proxychains_resolver == DNSLF_LIBC)
 		true_freeaddrinfo(res);
 	else
 		proxy_freeaddrinfo(res);
@@ -672,7 +684,7 @@ int pc_getnameinfo(const struct sockaddr *sa, socklen_t salen,
 	INIT();
 	PFUNC();
 
-	if(!proxychains_resolver) {
+	if(proxychains_resolver == DNSLF_LIBC) {
 		return true_getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
 	} else {
 		if(!salen || !(SOCKFAMILY(*sa) == AF_INET || SOCKFAMILY(*sa) == AF_INET6))
@@ -719,7 +731,7 @@ struct hostent *gethostbyaddr(const void *addr, socklen_t len, int type) {
 	static char *aliases[1];
 	static struct hostent he;
 
-	if(!proxychains_resolver)
+	if(proxychains_resolver == DNSLF_LIBC)
 		return true_gethostbyaddr(addr, len, type);
 	else {
 

src/proxychains.conf

@@ -48,17 +48,33 @@ strict_chain
 # Quiet mode (no output from library)
 #quiet_mode
 
-# Proxy DNS requests - no leak for DNS data
+## Proxy DNS requests - no leak for DNS data
-# this uses the proxychains4 style method to do remote dns
+# (disable all of the 3 items below to not proxy your DNS requests)
+
+# method 1. this uses the proxychains4 style method to do remote dns:
+# a thread is spawned that serves DNS requests and hands down an ip
+# assigned from an internal list (via remote_dns_subset).
+# this is the easiest (setup-wise) and fastest method, however on
+# systems with buggy libcs and very complex software like webbrosers
+# this might not work and/or cause crashes.
 proxy_dns
 
-# use the old proxyresolv script to proxy DNS requests
+# method 2. use the old proxyresolv script to proxy DNS requests
-# in proxychains 3.1 style. requires proxyresolv in $PATH
+# in proxychains 3.1 style. requires `proxyresolv` in $PATH
 # plus a dynamically linked `dig` binary.
 # this is a lot slower than `proxy_dns`, doesn't support .onion URLs,
 # but might be more compatible with complex software like webbrowsers.
 #proxy_dns_old
 
+# method 3. use proxychains4-daemon process to serve remote DNS requests.
+# this is similar to the threaded `proxy_dns` method, however it requires
+# that proxychains4-daemon is already running on the specified address.
+# on the plus side it doesn't do malloc/threads so it should be quite
+# compatible with complex, async-unsafe software.
+# note that if you don't start proxychains4-daemon before using this,
+# the process will simply hang.
+#proxy_dns_daemon 127.0.0.1:1053
+
 # set the class A subnet number to use for the internal remote DNS mapping
 # we use the reserved 224.x.x.x range by default,
 # if the proxified app does a DNS request, we will return an IP from that range.

src/rdns.c

@@ -0,0 +1,99 @@
+#include <sys/socket.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "rdns.h"
+#include "allocator_thread.h"
+#include "remotedns.h"
+
+#ifndef HAVE_SOCK_CLOEXEC
+#define SOCK_CLOEXEC 0
+#endif
+
+//static enum dns_lookup_flavor dns_flavor;
+#define dns_flavor rdns_get_flavor()
+
+static struct sockaddr_in rdns_server;
+
+size_t rdns_daemon_get_host_for_ip(ip_type4 ip, char* readbuf) {
+	struct at_msg msg = {
+		.h.msgtype = ATM_GETNAME,
+		.h.datalen = htons(4),
+		.m.ip = ip,
+	};
+	int fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+	sendto(fd, &msg, sizeof(msg.h)+4, 0, (void*)&rdns_server, sizeof(rdns_server));
+	recvfrom(fd, &msg, sizeof msg, 0, (void*)0, (void*)0);
+	close(fd);
+	msg.h.datalen = ntohs(msg.h.datalen);
+	if(!msg.h.datalen || msg.h.datalen > 256) return 0;
+	memcpy(readbuf, msg.m.host, msg.h.datalen);
+	return msg.h.datalen - 1;
+}
+
+static ip_type4 rdns_daemon_get_ip_for_host(char* host, size_t len) {
+	struct at_msg msg = {
+		.h.msgtype = ATM_GETIP,
+	};
+	if(len >= 256) return IPT4_INT(-1);
+	memcpy(msg.m.host, host, len+1);
+	msg.h.datalen = htons(len+1);
+	int fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+	sendto(fd, &msg, sizeof(msg.h)+len+1, 0, (void*)&rdns_server, sizeof(rdns_server));
+	recvfrom(fd, &msg, sizeof msg, 0, (void*)0, (void*)0);
+	close(fd);
+	if(ntohs(msg.h.datalen) != 4) return IPT4_INT(-1);
+	return msg.m.ip;
+}
+
+const char *rdns_resolver_string(enum dns_lookup_flavor flavor) {
+	static const char tab[][7] = {
+		[DNSLF_LIBC] = "off",
+		[DNSLF_FORKEXEC] = "old",
+		[DNSLF_RDNS_THREAD] = "thread",
+		[DNSLF_RDNS_DAEMON] = "daemon",
+	};
+	return tab[flavor];
+}
+
+void rdns_init(enum dns_lookup_flavor flavor) {
+	static int init_done = 0;
+	if(!init_done) switch(flavor) {
+		case DNSLF_RDNS_THREAD:
+			at_init();
+			break;
+		case DNSLF_RDNS_DAEMON:
+		default:
+			break;
+	}
+	init_done = 1;
+}
+
+void rdns_set_daemon(struct sockaddr_in* addr) {
+	rdns_server = *addr;
+}
+
+#if 0
+enum dns_lookup_flavor rdns_get_flavor(void) {
+	return dns_flavor;
+}
+#endif
+
+size_t rdns_get_host_for_ip(ip_type4 ip, char* readbuf) {
+	switch(dns_flavor) {
+		case DNSLF_RDNS_THREAD: return at_get_host_for_ip(ip, readbuf);
+		case DNSLF_RDNS_DAEMON: return rdns_daemon_get_host_for_ip(ip, readbuf);
+		default:
+			abort();
+	}
+}
+
+ip_type4 rdns_get_ip_for_host(char* host, size_t len) {
+	switch(dns_flavor) {
+		case DNSLF_RDNS_THREAD: return at_get_ip_for_host(host, len);
+		case DNSLF_RDNS_DAEMON: return rdns_daemon_get_ip_for_host(host, len);
+		default:
+			abort();
+	}
+}
+

src/rdns.h

@@ -0,0 +1,28 @@
+#ifndef RDNS_H
+#define RDNS_H
+
+#include <unistd.h>
+#include <netinet/in.h>
+#include "ip_type.h"
+#include "remotedns.h"
+
+enum dns_lookup_flavor {
+	DNSLF_LIBC = 0,
+	DNSLF_FORKEXEC,
+
+	DNSLF_RDNS_START,
+	DNSLF_RDNS_THREAD = DNSLF_RDNS_START,
+	DNSLF_RDNS_DAEMON,
+};
+
+void rdns_init(enum dns_lookup_flavor flavor);
+void rdns_set_daemon(struct sockaddr_in* addr);
+const char *rdns_resolver_string(enum dns_lookup_flavor flavor);
+size_t rdns_get_host_for_ip(ip_type4 ip, char* readbuf);
+ip_type4 rdns_get_ip_for_host(char* host, size_t len);
+
+//enum dns_lookup_flavor rdns_get_flavor(void);
+#define rdns_get_flavor() proxychains_resolver
+extern enum dns_lookup_flavor proxychains_resolver;
+
+#endif

src/remotedns.h

@@ -4,6 +4,8 @@
 #include <unistd.h>
 #include "ip_type.h"
 
+#define MSG_LEN_MAX 256
+
 enum at_msgtype {
 	ATM_GETIP = 0,
 	ATM_GETNAME,