From 27fdc23433c913e8d75ff005afce34bdfcd16c1a Mon Sep 17 00:00:00 2001 From: Erik Ekman Date: Sun, 16 Aug 2009 12:30:26 +0000 Subject: [PATCH] Split the client code out from the file with the main() func --- src/Makefile | 2 +- src/client.c | 1131 +++++++++++++++++++++++++++++++++++++++++++++++++ src/client.h | 33 ++ src/iodine.c | 1141 +------------------------------------------------- src/login.c | 2 +- src/login.h | 2 +- src/util.c | 69 +++ src/util.h | 6 + 8 files changed, 1259 insertions(+), 1127 deletions(-) create mode 100644 src/client.c create mode 100644 src/client.h create mode 100644 src/util.c create mode 100644 src/util.h diff --git a/src/Makefile b/src/Makefile index e281142..3cfdea7 100644 --- a/src/Makefile +++ b/src/Makefile @@ -1,5 +1,5 @@ COMMONOBJS = tun.o dns.o read.o encoding.o login.o base32.o base64.o md5.o common.o -CLIENTOBJS = iodine.o +CLIENTOBJS = iodine.o client.o util.o CLIENT = ../bin/iodine SERVEROBJS = iodined.o user.o fw_query.o SERVER = ../bin/iodined diff --git a/src/client.c b/src/client.c new file mode 100644 index 0000000..bd516cf --- /dev/null +++ b/src/client.c @@ -0,0 +1,1131 @@ +/* + * Copyright (c) 2006-2009 Bjorn Andersson , Erik Ekman + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifdef WINDOWS32 +#include "windows.h" +#include +#else +#include +#ifdef DARWIN +#include +#endif +#include +#include +#include +#include +#include +#include +#include +#endif + +#include "common.h" +#include "encoding.h" +#include "base32.h" +#include "base64.h" +#include "dns.h" +#include "login.h" +#include "tun.h" +#include "version.h" +#include "client.h" + +#define PING_TIMEOUT(t) ((t) >= (conn == CONN_DNS_NULL ? 1 : 20)) + +static int running; +static const char *password; + +static struct sockaddr_in nameserv; +static struct sockaddr_in raw_serv; +static const char *topdomain; + +static uint16_t rand_seed; +static int downstream_seqno; +static int downstream_fragment; +static int down_ack_seqno; +static int down_ack_fragment; + +/* Current up/downstream IP packet */ +static struct packet outpkt; +static struct packet inpkt; + +/* My userid at the server */ +static char userid; + +/* DNS id for next packet */ +static uint16_t chunkid; + +/* Base32 encoder used for non-data packets */ +static struct encoder *b32; + +/* The encoder used for data packets + * Defaults to Base32, can be changed after handshake */ +static struct encoder *dataenc; + +/* My connection mode */ +static enum connection conn; + +void +client_init() +{ + running = 1; + outpkt.seqno = 0; + inpkt.len = 0; + downstream_seqno = 0; + downstream_fragment = 0; + down_ack_seqno = 0; + down_ack_fragment = 0; + chunkid = 0; + b32 = get_base32_encoder(); + dataenc = get_base32_encoder(); + rand_seed = rand(); + conn = CONN_DNS_NULL; +} + +void +client_stop() +{ + running = 0; +} + +enum connection +client_get_conn() +{ + return conn; +} + +void +client_set_nameserver(const char *cp) +{ + struct in_addr addr; + + if (inet_aton(cp, &addr) != 1) + errx(1, "error parsing nameserver address: '%s'", cp); + + memset(&nameserv, 0, sizeof(nameserv)); + nameserv.sin_family = AF_INET; + nameserv.sin_port = htons(53); + nameserv.sin_addr = addr; +} + +void +client_set_topdomain(const char *cp) +{ + topdomain = cp; +} + +void +client_set_password(const char *cp) +{ + password = cp; +} + +const char * +client_get_raw_addr() +{ + return inet_ntoa(raw_serv.sin_addr); +} + +static void +send_query(int fd, char *hostname) +{ + char packet[4096]; + struct query q; + size_t len; + + q.id = ++chunkid; + q.type = T_NULL; + + len = dns_encode(packet, sizeof(packet), &q, QR_QUERY, hostname, strlen(hostname)); + + sendto(fd, packet, len, 0, (struct sockaddr*)&nameserv, sizeof(nameserv)); +} + +static void +send_raw(int fd, char *buf, int buflen, int user, int cmd) +{ + char packet[4096]; + int len; + + len = MIN(sizeof(packet) - RAW_HDR_LEN, buflen); + + memcpy(packet, raw_header, RAW_HDR_LEN); + if (len) { + memcpy(&packet[RAW_HDR_LEN], buf, len); + } + + len += RAW_HDR_LEN; + packet[RAW_HDR_CMD] = cmd | (user & 0x0F); + + sendto(fd, packet, len, 0, (struct sockaddr*)&raw_serv, sizeof(raw_serv)); +} + +static void +send_raw_data(int dns_fd) +{ + send_raw(dns_fd, outpkt.data, outpkt.len, userid, RAW_HDR_CMD_DATA); +} + +static int +build_hostname(char *buf, size_t buflen, + const char *data, const size_t datalen, + const char *topdomain, struct encoder *encoder) +{ + int encsize; + size_t space; + char *b; + + space = MIN(0xFF, buflen) - strlen(topdomain) - 7; + if (!encoder->places_dots()) + space -= (space / 57); /* space for dots */ + + memset(buf, 0, buflen); + + encsize = encoder->encode(buf, &space, data, datalen); + + if (!encoder->places_dots()) + inline_dotify(buf, buflen); + + b = buf; + b += strlen(buf); + + if (*b != '.') + *b++ = '.'; + + strncpy(b, topdomain, strlen(topdomain)+1); + + return space; +} + +static void +send_packet(int fd, char cmd, const char *data, const size_t datalen) +{ + char buf[4096]; + + buf[0] = cmd; + + build_hostname(buf + 1, sizeof(buf) - 1, data, datalen, topdomain, b32); + send_query(fd, buf); +} + +static int +is_sending() +{ + return (outpkt.len != 0); +} + +static void +send_chunk(int fd) +{ + char hex[] = "0123456789ABCDEF"; + char buf[4096]; + int avail; + int code; + char *p; + + p = outpkt.data; + p += outpkt.offset; + avail = outpkt.len - outpkt.offset; + + outpkt.sentlen = build_hostname(buf + 4, sizeof(buf) - 4, p, avail, topdomain, dataenc); + + /* Build upstream data header (see doc/proto_xxxxxxxx.txt) */ + + buf[0] = hex[userid & 15]; /* First byte is 4 bits userid */ + + code = ((outpkt.seqno & 7) << 2) | ((outpkt.fragment & 15) >> 2); + buf[1] = b32_5to8(code); /* Second byte is 3 bits seqno, 2 upper bits fragment count */ + + code = ((outpkt.fragment & 3) << 3) | (downstream_seqno & 7); + buf[2] = b32_5to8(code); /* Third byte is 2 bits lower fragment count, 3 bits downstream packet seqno */ + + code = ((downstream_fragment & 15) << 1) | (outpkt.sentlen == avail); + buf[3] = b32_5to8(code); /* Fourth byte is 4 bits downstream fragment count, 1 bit last frag flag */ + + down_ack_seqno = downstream_seqno; + down_ack_fragment = downstream_fragment; + + outpkt.fragment++; + send_query(fd, buf); +} + +static void +send_ping(int fd) +{ + if (conn == CONN_DNS_NULL) { + char data[4]; + + if (is_sending()) { + outpkt.sentlen = 0; + outpkt.offset = 0; + outpkt.len = 0; + } + + data[0] = userid; + data[1] = ((downstream_seqno & 7) << 4) | (downstream_fragment & 15); + data[2] = (rand_seed >> 8) & 0xff; + data[3] = (rand_seed >> 0) & 0xff; + + down_ack_seqno = downstream_seqno; + down_ack_fragment = downstream_fragment; + + rand_seed++; + + send_packet(fd, 'P', data, sizeof(data)); + } else { + send_raw(fd, NULL, 0, userid, RAW_HDR_CMD_PING); + } +} + +static int +read_dns(int dns_fd, int tun_fd, char *buf, int buflen) /* FIXME: tun_fd needed for raw handling */ +{ + struct sockaddr_in from; + char data[64*1024]; + socklen_t addrlen; + struct query q; + int r; + + addrlen = sizeof(struct sockaddr); + if ((r = recvfrom(dns_fd, data, sizeof(data), 0, + (struct sockaddr*)&from, &addrlen)) == -1) { + warn("recvfrom"); + return 0; + } + + if (conn == CONN_DNS_NULL) { + int rv; + + rv = dns_decode(buf, buflen, &q, QR_ANSWER, data, r); + + /* decode the data header, update seqno and frag before next request */ + if (rv >= 2) { + downstream_seqno = (buf[1] >> 5) & 7; + downstream_fragment = (buf[1] >> 1) & 15; + } + + + if (is_sending()) { + if (chunkid == q.id) { + /* Got ACK on sent packet */ + outpkt.offset += outpkt.sentlen; + if (outpkt.offset == outpkt.len) { + /* Packet completed */ + outpkt.offset = 0; + outpkt.len = 0; + outpkt.sentlen = 0; + + /* If the ack contains unacked frag number but no data, + * send a ping to ack the frag number and get more data*/ + if (rv == 2 && ( + downstream_seqno != down_ack_seqno || + downstream_fragment != down_ack_fragment + )) { + + send_ping(dns_fd); + } + } else { + /* More to send */ + send_chunk(dns_fd); + } + } + } + return rv; + } else { /* CONN_RAW_UDP */ + unsigned long datalen; + char buf[64*1024]; + + /* minimum length */ + if (r < RAW_HDR_LEN) return 0; + /* should start with header */ + if (memcmp(data, raw_header, RAW_HDR_IDENT_LEN)) return 0; + /* should be data packet */ + if (RAW_HDR_GET_CMD(data) != RAW_HDR_CMD_DATA) return 0; + /* should be my user id */ + if (RAW_HDR_GET_USR(data) != userid) return 0; + + r -= RAW_HDR_LEN; + datalen = sizeof(buf); + if (uncompress((uint8_t*)buf, &datalen, (uint8_t*) &data[RAW_HDR_LEN], r) == Z_OK) { + write_tun(tun_fd, buf, datalen); + } + return 0; + } +} + + +static int +tunnel_tun(int tun_fd, int dns_fd) +{ + unsigned long outlen; + unsigned long inlen; + char out[64*1024]; + char in[64*1024]; + ssize_t read; + + if ((read = read_tun(tun_fd, in, sizeof(in))) <= 0) + return -1; + + outlen = sizeof(out); + inlen = read; + compress2((uint8_t*)out, &outlen, (uint8_t*)in, inlen, 9); + + memcpy(outpkt.data, out, MIN(outlen, sizeof(outpkt.data))); + outpkt.sentlen = 0; + outpkt.offset = 0; + outpkt.len = outlen; + outpkt.seqno++; + outpkt.fragment = 0; + + if (conn == CONN_DNS_NULL) { + send_chunk(dns_fd); + } else { + send_raw_data(dns_fd); + } + + return read; +} + +static int +tunnel_dns(int tun_fd, int dns_fd) +{ + unsigned long datalen; + char buf[64*1024]; + size_t read; + + if ((read = read_dns(dns_fd, tun_fd, buf, sizeof(buf))) <= 2) + return -1; + + if (downstream_seqno != inpkt.seqno) { + /* New packet */ + inpkt.seqno = downstream_seqno; + inpkt.fragment = downstream_fragment; + inpkt.len = 0; + } else if (downstream_fragment <= inpkt.fragment) { + /* Duplicate fragment */ + return -1; + } + inpkt.fragment = downstream_fragment; + + datalen = MIN(read - 2, sizeof(inpkt.data) - inpkt.len); + + /* Skip 2 byte data header and append to packet */ + memcpy(&inpkt.data[inpkt.len], &buf[2], datalen); + inpkt.len += datalen; + + if (buf[1] & 1) { /* If last fragment flag is set */ + /* Uncompress packet and send to tun */ + datalen = sizeof(buf); + if (uncompress((uint8_t*)buf, &datalen, (uint8_t*) inpkt.data, inpkt.len) == Z_OK) { + write_tun(tun_fd, buf, datalen); + } + inpkt.len = 0; + } + + /* If we have nothing to send, send a ping to get more data */ + if (!is_sending()) + send_ping(dns_fd); + + return read; +} + +int +client_tunnel(int tun_fd, int dns_fd) +{ + struct timeval tv; + fd_set fds; + int rv; + int i; + int seconds; + + rv = 0; + seconds = 0; + + while (running) { + tv.tv_sec = 1; + tv.tv_usec = 0; + + + FD_ZERO(&fds); + if ((!is_sending()) || conn == CONN_RAW_UDP) { + FD_SET(tun_fd, &fds); + } + FD_SET(dns_fd, &fds); + + i = select(MAX(tun_fd, dns_fd) + 1, &fds, NULL, NULL, &tv); + + if (running == 0) + break; + + if (i < 0) + err(1, "select"); + + if (i == 0) { /* timeout */ + seconds++; + } else { + if (FD_ISSET(tun_fd, &fds)) { + seconds = 0; + if (tunnel_tun(tun_fd, dns_fd) <= 0) + continue; + } + if (FD_ISSET(dns_fd, &fds)) { + if (tunnel_dns(tun_fd, dns_fd) <= 0) + continue; + } + } + + if (PING_TIMEOUT(seconds)) { + send_ping(dns_fd); + seconds = 0; + } + } + + return rv; +} + +static void +send_login(int fd, char *login, int len) +{ + char data[19]; + + memset(data, 0, sizeof(data)); + data[0] = userid; + memcpy(&data[1], login, MIN(len, 16)); + + data[17] = (rand_seed >> 8) & 0xff; + data[18] = (rand_seed >> 0) & 0xff; + + rand_seed++; + + send_packet(fd, 'L', data, sizeof(data)); +} + +static void +send_fragsize_probe(int fd, int fragsize) +{ + char probedata[256]; + char buf[4096]; + + /* build a large query domain which is random and maximum size */ + memset(probedata, MIN(1, rand_seed & 0xff), sizeof(probedata)); + probedata[1] = MIN(1, (rand_seed >> 8) & 0xff); + rand_seed++; + build_hostname(buf + 4, sizeof(buf) - 4, probedata, sizeof(probedata), topdomain, dataenc); + + fragsize &= 2047; + + buf[0] = 'r'; /* Probe downstream fragsize packet */ + buf[1] = b32_5to8((userid << 1) | ((fragsize >> 10) & 1)); + buf[2] = b32_5to8((fragsize >> 5) & 31); + buf[3] = b32_5to8(fragsize & 31); + + send_query(fd, buf); +} + +static void +send_set_downstream_fragsize(int fd, int fragsize) +{ + char data[5]; + + data[0] = userid; + data[1] = (fragsize & 0xff00) >> 8; + data[2] = (fragsize & 0x00ff); + data[3] = (rand_seed >> 8) & 0xff; + data[4] = (rand_seed >> 0) & 0xff; + + rand_seed++; + + send_packet(fd, 'N', data, sizeof(data)); +} + +static void +send_version(int fd, uint32_t version) +{ + char data[6]; + + data[0] = (version >> 24) & 0xff; + data[1] = (version >> 16) & 0xff; + data[2] = (version >> 8) & 0xff; + data[3] = (version >> 0) & 0xff; + + data[4] = (rand_seed >> 8) & 0xff; + data[5] = (rand_seed >> 0) & 0xff; + + rand_seed++; + + send_packet(fd, 'V', data, sizeof(data)); +} + +static void +send_ip_request(int fd, int userid) +{ + char buf[512] = "I____."; + buf[1] = b32_5to8(userid); + + buf[2] = b32_5to8((rand_seed >> 10) & 0x1f); + buf[3] = b32_5to8((rand_seed >> 5) & 0x1f); + buf[4] = b32_5to8((rand_seed ) & 0x1f); + rand_seed++; + + strncat(buf, topdomain, 512 - strlen(buf)); + send_query(fd, buf); +} + +static void +send_raw_udp_login(int dns_fd, int userid, int seed) +{ + char buf[16]; + login_calculate(buf, 16, password, seed + 1); + + send_raw(dns_fd, buf, sizeof(buf), userid, RAW_HDR_CMD_LOGIN); +} + +static void +send_case_check(int fd) +{ + /* The '+' plus character is not allowed according to RFC. + * Expect to get SERVFAIL or similar if it is rejected. + */ + char buf[512] = "zZ+-aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyY1234."; + + strncat(buf, topdomain, 512 - strlen(buf)); + send_query(fd, buf); +} + +static void +send_codec_switch(int fd, int userid, int bits) +{ + char buf[512] = "S_____."; + buf[1] = b32_5to8(userid); + buf[2] = b32_5to8(bits); + + buf[3] = b32_5to8((rand_seed >> 10) & 0x1f); + buf[4] = b32_5to8((rand_seed >> 5) & 0x1f); + buf[5] = b32_5to8((rand_seed ) & 0x1f); + rand_seed++; + + strncat(buf, topdomain, 512 - strlen(buf)); + send_query(fd, buf); +} + +static int +handshake_version(int dns_fd, int *seed) +{ + struct timeval tv; + char in[4096]; + fd_set fds; + uint32_t payload; + int i; + int r; + int read; + + for (i = 0; running && i < 5; i++) { + tv.tv_sec = i + 1; + tv.tv_usec = 0; + + send_version(dns_fd, VERSION); + + FD_ZERO(&fds); + FD_SET(dns_fd, &fds); + + r = select(dns_fd + 1, &fds, NULL, NULL, &tv); + + if(r > 0) { + read = read_dns(dns_fd, 0, in, sizeof(in)); + + if(read <= 0) { + if (read == 0) { + warn("handshake read"); + } + /* if read < 0 then warning has been printed already */ + continue; + } + + if (read >= 9) { + payload = (((in[4] & 0xff) << 24) | + ((in[5] & 0xff) << 16) | + ((in[6] & 0xff) << 8) | + ((in[7] & 0xff))); + + if (strncmp("VACK", in, 4) == 0) { + *seed = payload; + userid = in[8]; + + fprintf(stderr, "Version ok, both using protocol v 0x%08x. You are user #%d\n", VERSION, userid); + return 0; + } else if (strncmp("VNAK", in, 4) == 0) { + warnx("You use protocol v 0x%08x, server uses v 0x%08x. Giving up", + VERSION, payload); + return 1; + } else if (strncmp("VFUL", in, 4) == 0) { + warnx("Server full, all %d slots are taken. Try again later", payload); + return 1; + } + } else + warnx("did not receive proper login challenge"); + } + + fprintf(stderr, "Retrying version check...\n"); + } + warnx("couldn't connect to server"); + return 1; +} + +static int +handshake_login(int dns_fd, int seed) +{ + struct timeval tv; + char in[4096]; + char login[16]; + char server[65]; + char client[65]; + int mtu; + fd_set fds; + int i; + int r; + int read; + + login_calculate(login, 16, password, seed); + + for (i=0; running && i<5 ;i++) { + tv.tv_sec = i + 1; + tv.tv_usec = 0; + + send_login(dns_fd, login, 16); + + FD_ZERO(&fds); + FD_SET(dns_fd, &fds); + + r = select(dns_fd + 1, &fds, NULL, NULL, &tv); + + if(r > 0) { + read = read_dns(dns_fd, 0, in, sizeof(in)); + + if(read <= 0) { + warn("read"); + continue; + } + + if (read > 0) { + int netmask; + if (strncmp("LNAK", in, 4) == 0) { + fprintf(stderr, "Bad password\n"); + return 1; + } else if (sscanf(in, "%64[^-]-%64[^-]-%d-%d", + server, client, &mtu, &netmask) == 4) { + + server[64] = 0; + client[64] = 0; + if (tun_setip(client, netmask) == 0 && + tun_setmtu(mtu) == 0) { + return 0; + } else { + errx(4, "Failed to set IP and MTU"); + } + } else { + fprintf(stderr, "Received bad handshake\n"); + } + } + } + + fprintf(stderr, "Retrying login...\n"); + } + warnx("couldn't login to server"); + return 1; +} + +static int +handshake_raw_udp(int dns_fd, int seed) +{ + struct timeval tv; + char in[4096]; + fd_set fds; + int i; + int r; + int len; + unsigned remoteaddr = 0; + struct in_addr server; + + fprintf(stderr, "Testing raw UDP data to the server (skip with -r)\n"); + for (i=0; running && i<3 ;i++) { + tv.tv_sec = i + 1; + tv.tv_usec = 0; + + send_ip_request(dns_fd, userid); + + FD_ZERO(&fds); + FD_SET(dns_fd, &fds); + + r = select(dns_fd + 1, &fds, NULL, NULL, &tv); + + if(r > 0) { + len = read_dns(dns_fd, 0, in, sizeof(in)); + if (len == 5 && in[0] == 'I') { + /* Received IP address */ + remoteaddr = (in[1] & 0xff); + remoteaddr <<= 8; + remoteaddr |= (in[2] & 0xff); + remoteaddr <<= 8; + remoteaddr |= (in[3] & 0xff); + remoteaddr <<= 8; + remoteaddr |= (in[4] & 0xff); + server.s_addr = ntohl(remoteaddr); + break; + } + } else { + fprintf(stderr, "."); + fflush(stderr); + } + } + + if (!remoteaddr) { + fprintf(stderr, "Failed to get raw server IP, will use DNS mode.\n"); + return 0; + } + fprintf(stderr, "Server is at %s, trying raw login: ", inet_ntoa(server)); + fflush(stderr); + + /* Store address to iodined server */ + memset(&raw_serv, 0, sizeof(raw_serv)); + raw_serv.sin_family = AF_INET; + raw_serv.sin_port = htons(53); + raw_serv.sin_addr = server; + + /* do login against port 53 on remote server + * based on the old seed. If reply received, + * switch to raw udp mode */ + for (i=0; running && i<4 ;i++) { + tv.tv_sec = i + 1; + tv.tv_usec = 0; + + send_raw_udp_login(dns_fd, userid, seed); + + FD_ZERO(&fds); + FD_SET(dns_fd, &fds); + + r = select(dns_fd + 1, &fds, NULL, NULL, &tv); + + if(r > 0) { + /* recv() needed for windows, dont change to read() */ + len = recv(dns_fd, in, sizeof(in), 0); + if (len >= (16 + RAW_HDR_LEN)) { + char hash[16]; + login_calculate(hash, 16, password, seed - 1); + if (memcmp(in, raw_header, RAW_HDR_IDENT_LEN) == 0 + && RAW_HDR_GET_CMD(in) == RAW_HDR_CMD_LOGIN + && memcmp(&in[RAW_HDR_LEN], hash, sizeof(hash)) == 0) { + + fprintf(stderr, "OK\n"); + return 1; + } + } + } + fprintf(stderr, "."); + fflush(stderr); + } + + fprintf(stderr, "failed\n"); + return 0; +} + +static int +handshake_case_check(int dns_fd) +{ + struct timeval tv; + char in[4096]; + fd_set fds; + int i; + int r; + int read; + int case_preserved; + + case_preserved = 0; + for (i=0; running && i<5 ;i++) { + tv.tv_sec = i + 1; + tv.tv_usec = 0; + + send_case_check(dns_fd); + + FD_ZERO(&fds); + FD_SET(dns_fd, &fds); + + r = select(dns_fd + 1, &fds, NULL, NULL, &tv); + + if(r > 0) { + read = read_dns(dns_fd, 0, in, sizeof(in)); + + if (read > 0) { + if (in[0] == 'z' || in[0] == 'Z') { + if (read < (27 * 2)) { + fprintf(stderr, "Received short case check reply. Will use base32 encoder\n"); + return case_preserved; + } else { + int k; + + /* TODO enhance this, base128 is probably also possible */ + case_preserved = 1; + for (k = 0; k < 27 && case_preserved; k += 2) { + if (in[k] == in[k+1]) { + /* test string: zZ+-aAbBcCdDeE... */ + case_preserved = 0; + } + } + return case_preserved; + } + } else { + fprintf(stderr, "Received bad case check reply\n"); + } + } else { + fprintf(stderr, "Got error on case check, will use base32\n"); + return case_preserved; + } + } + + fprintf(stderr, "Retrying case check...\n"); + } + + fprintf(stderr, "No reply on case check, continuing\n"); + return case_preserved; +} + +static void +handshake_switch_codec(int dns_fd) +{ + struct timeval tv; + char in[4096]; + fd_set fds; + int i; + int r; + int read; + + dataenc = get_base64_encoder(); + fprintf(stderr, "Switching to %s codec\n", dataenc->name); + /* Send to server that this user will use base64 from now on */ + for (i=0; running && i<5 ;i++) { + int bits; + tv.tv_sec = i + 1; + tv.tv_usec = 0; + + bits = 6; /* base64 = 6 bits per byte */ + + send_codec_switch(dns_fd, userid, bits); + + FD_ZERO(&fds); + FD_SET(dns_fd, &fds); + + r = select(dns_fd + 1, &fds, NULL, NULL, &tv); + + if(r > 0) { + read = read_dns(dns_fd, 0, in, sizeof(in)); + + if (read > 0) { + if (strncmp("BADLEN", in, 6) == 0) { + fprintf(stderr, "Server got bad message length. "); + goto codec_revert; + } else if (strncmp("BADIP", in, 5) == 0) { + fprintf(stderr, "Server rejected sender IP address. "); + goto codec_revert; + } else if (strncmp("BADCODEC", in, 8) == 0) { + fprintf(stderr, "Server rejected the selected codec. "); + goto codec_revert; + } + in[read] = 0; /* zero terminate */ + fprintf(stderr, "Server switched to codec %s\n", in); + return; + } + } + fprintf(stderr, "Retrying codec switch...\n"); + } + fprintf(stderr, "No reply from server on codec switch. "); + +codec_revert: + fprintf(stderr, "Falling back to base32\n"); + dataenc = get_base32_encoder(); +} + +static int +handshake_autoprobe_fragsize(int dns_fd) +{ + struct timeval tv; + char in[4096]; + fd_set fds; + int i; + int r; + int read; + int proposed_fragsize = 768; + int range = 768; + int max_fragsize = 0; + + max_fragsize = 0; + fprintf(stderr, "Autoprobing max downstream fragment size... (skip with -m fragsize)\n"); + while (running && range > 0 && (range >= 8 || !max_fragsize)) { + for (i=0; running && i<3 ;i++) { + tv.tv_sec = 1; + tv.tv_usec = 0; + send_fragsize_probe(dns_fd, proposed_fragsize); + + FD_ZERO(&fds); + FD_SET(dns_fd, &fds); + + r = select(dns_fd + 1, &fds, NULL, NULL, &tv); + + if(r > 0) { + read = read_dns(dns_fd, 0, in, sizeof(in)); + + if (read > 0) { + /* We got a reply */ + int acked_fragsize = ((in[0] & 0xff) << 8) | (in[1] & 0xff); + if (acked_fragsize == proposed_fragsize) { + if (read == proposed_fragsize) { + fprintf(stderr, "%d ok.. ", acked_fragsize); + fflush(stderr); + max_fragsize = acked_fragsize; + } + } + if (strncmp("BADIP", in, 5) == 0) { + fprintf(stderr, "got BADIP.. "); + fflush(stderr); + } + break; + } + } + fprintf(stderr, "."); + fflush(stderr); + } + range >>= 1; + if (max_fragsize == proposed_fragsize) { + /* Try bigger */ + proposed_fragsize += range; + } else { + /* Try smaller */ + fprintf(stderr, "%d not ok.. ", proposed_fragsize); + fflush(stderr); + proposed_fragsize -= range; + } + } + if (!running) { + fprintf(stderr, "\n"); + warnx("stopped while autodetecting fragment size (Try probing manually with -m)"); + return 0; + } + if (range == 0) { + /* Tried all the way down to 2 and found no good size */ + fprintf(stderr, "\n"); + warnx("found no accepted fragment size. (Try probing manually with -m)"); + return 0; + } + fprintf(stderr, "will use %d\n", max_fragsize); + return max_fragsize; +} + +static void +handshake_set_fragsize(int dns_fd, int fragsize) +{ + struct timeval tv; + char in[4096]; + fd_set fds; + int i; + int r; + int read; + + fprintf(stderr, "Setting downstream fragment size to max %d...\n", fragsize); + for (i=0; running && i<5 ;i++) { + tv.tv_sec = i + 1; + tv.tv_usec = 0; + + send_set_downstream_fragsize(dns_fd, fragsize); + + FD_ZERO(&fds); + FD_SET(dns_fd, &fds); + + r = select(dns_fd + 1, &fds, NULL, NULL, &tv); + + if(r > 0) { + read = read_dns(dns_fd, 0, in, sizeof(in)); + + if (read > 0) { + int accepted_fragsize; + + if (strncmp("BADFRAG", in, 7) == 0) { + fprintf(stderr, "Server rejected fragsize. Keeping default."); + return; + } else if (strncmp("BADIP", in, 5) == 0) { + fprintf(stderr, "Server rejected sender IP address.\n"); + return; + } + + accepted_fragsize = ((in[0] & 0xff) << 8) | (in[1] & 0xff); + return; + } + } + fprintf(stderr, "Retrying set fragsize...\n"); + } + fprintf(stderr, "No reply from server when setting fragsize. Keeping default.\n"); +} + +int +client_handshake(int dns_fd, int raw_mode, int autodetect_frag_size, int fragsize) +{ + int seed; + int case_preserved; + int r; + + r = handshake_version(dns_fd, &seed); + if (r) { + return r; + } + + r = handshake_login(dns_fd, seed); + if (r) { + return r; + } + + if (raw_mode && handshake_raw_udp(dns_fd, seed)) { + conn = CONN_RAW_UDP; + } else { + if (raw_mode == 0) { + fprintf(stderr, "Skipping raw mode\n"); + } + case_preserved = handshake_case_check(dns_fd); + + if (case_preserved) { + handshake_switch_codec(dns_fd); + } + + if (autodetect_frag_size) { + fragsize = handshake_autoprobe_fragsize(dns_fd); + if (!fragsize) { + return 1; + } + } + + handshake_set_fragsize(dns_fd, fragsize); + } + + return 0; +} + diff --git a/src/client.h b/src/client.h new file mode 100644 index 0000000..0df4d3d --- /dev/null +++ b/src/client.h @@ -0,0 +1,33 @@ +/* + * Copyright (c) 2006-2009 Bjorn Andersson , Erik Ekman + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#ifndef __CLIENT_H__ +#define __CLIENT_H__ + +void client_init(); +void client_stop(); + +enum connection client_get_conn(); +const char *client_get_raw_addr(); + +void client_set_nameserver(const char *cp); +void client_set_topdomain(const char *cp); +void client_set_password(const char *cp); + +int client_handshake(int dns_fd, int raw_mode, int autodetect_frag_size, int fragsize); +int client_tunnel(int tun_fd, int dns_fd); + +#endif diff --git a/src/iodine.c b/src/iodine.c index da0aa79..d40c338 100644 --- a/src/iodine.c +++ b/src/iodine.c @@ -24,82 +24,26 @@ #include #include #include -#include #include #ifdef WINDOWS32 #include "windows.h" #include #else -#include -#ifdef DARWIN -#include -#endif -#include -#include -#include -#include #include #include -#include #endif #include "common.h" -#include "encoding.h" -#include "base32.h" -#include "base64.h" -#include "dns.h" -#include "login.h" #include "tun.h" -#include "version.h" +#include "client.h" +#include "util.h" #ifdef WINDOWS32 WORD req_version = MAKEWORD(2, 2); WSADATA wsa_data; #endif -#define PING_TIMEOUT(t) ((t) >= (conn == CONN_DNS_NULL ? 1 : 20)) - -static void send_ping(int fd); -static void send_chunk(int fd); -static void send_raw_data(int fd); -static int build_hostname(char *buf, size_t buflen, - const char *data, const size_t datalen, - const char *topdomain, struct encoder *encoder); - -static int running = 1; -static char password[33]; - -static struct sockaddr_in nameserv; -static struct sockaddr_in raw_serv; -static char *topdomain; - -static uint16_t rand_seed; -static int downstream_seqno; -static int downstream_fragment; -static int down_ack_seqno; -static int down_ack_fragment; - -/* Current up/downstream IP packet */ -static struct packet outpkt; -static struct packet inpkt; - -/* My userid at the server */ -static char userid; - -/* DNS id for next packet */ -static uint16_t chunkid; - -/* Base32 encoder used for non-data packets */ -static struct encoder *b32; - -/* The encoder used for data packets - * Defaults to Base32, can be changed after handshake */ -static struct encoder *dataenc; - -/* My connection mode */ -static enum connection conn; - #if !defined(BSD) && !defined(__GLIBC__) static char *__progname; #endif @@ -107,1050 +51,7 @@ static char *__progname; static void sighandler(int sig) { - running = 0; -} - -static void -send_query(int fd, char *hostname) -{ - char packet[4096]; - struct query q; - size_t len; - - q.id = ++chunkid; - q.type = T_NULL; - - len = dns_encode(packet, sizeof(packet), &q, QR_QUERY, hostname, strlen(hostname)); - - sendto(fd, packet, len, 0, (struct sockaddr*)&nameserv, sizeof(nameserv)); -} - -static void -send_raw(int fd, char *buf, int buflen, int user, int cmd) -{ - char packet[4096]; - int len; - - len = MIN(sizeof(packet) - RAW_HDR_LEN, buflen); - - memcpy(packet, raw_header, RAW_HDR_LEN); - if (len) { - memcpy(&packet[RAW_HDR_LEN], buf, len); - } - - len += RAW_HDR_LEN; - packet[RAW_HDR_CMD] = cmd | (user & 0x0F); - - sendto(fd, packet, len, 0, (struct sockaddr*)&raw_serv, sizeof(raw_serv)); -} - -static void -send_packet(int fd, char cmd, const char *data, const size_t datalen) -{ - char buf[4096]; - - buf[0] = cmd; - - build_hostname(buf + 1, sizeof(buf) - 1, data, datalen, topdomain, b32); - send_query(fd, buf); -} - -static int -build_hostname(char *buf, size_t buflen, - const char *data, const size_t datalen, - const char *topdomain, struct encoder *encoder) -{ - int encsize; - size_t space; - char *b; - - space = MIN(0xFF, buflen) - strlen(topdomain) - 7; - if (!encoder->places_dots()) - space -= (space / 57); /* space for dots */ - - memset(buf, 0, buflen); - - encsize = encoder->encode(buf, &space, data, datalen); - - if (!encoder->places_dots()) - inline_dotify(buf, buflen); - - b = buf; - b += strlen(buf); - - if (*b != '.') - *b++ = '.'; - - strncpy(b, topdomain, strlen(topdomain)+1); - - return space; -} - -static int -is_sending() -{ - return (outpkt.len != 0); -} - -static int -read_dns(int dns_fd, int tun_fd, char *buf, int buflen) /* FIXME: tun_fd needed for raw handling */ -{ - struct sockaddr_in from; - char data[64*1024]; - socklen_t addrlen; - struct query q; - int r; - - addrlen = sizeof(struct sockaddr); - if ((r = recvfrom(dns_fd, data, sizeof(data), 0, - (struct sockaddr*)&from, &addrlen)) == -1) { - warn("recvfrom"); - return 0; - } - - if (conn == CONN_DNS_NULL) { - int rv; - - rv = dns_decode(buf, buflen, &q, QR_ANSWER, data, r); - - /* decode the data header, update seqno and frag before next request */ - if (rv >= 2) { - downstream_seqno = (buf[1] >> 5) & 7; - downstream_fragment = (buf[1] >> 1) & 15; - } - - - if (is_sending()) { - if (chunkid == q.id) { - /* Got ACK on sent packet */ - outpkt.offset += outpkt.sentlen; - if (outpkt.offset == outpkt.len) { - /* Packet completed */ - outpkt.offset = 0; - outpkt.len = 0; - outpkt.sentlen = 0; - - /* If the ack contains unacked frag number but no data, - * send a ping to ack the frag number and get more data*/ - if (rv == 2 && ( - downstream_seqno != down_ack_seqno || - downstream_fragment != down_ack_fragment - )) { - - send_ping(dns_fd); - } - } else { - /* More to send */ - send_chunk(dns_fd); - } - } - } - return rv; - } else { /* CONN_RAW_UDP */ - unsigned long datalen; - char buf[64*1024]; - - /* minimum length */ - if (r < RAW_HDR_LEN) return 0; - /* should start with header */ - if (memcmp(data, raw_header, RAW_HDR_IDENT_LEN)) return 0; - /* should be data packet */ - if (RAW_HDR_GET_CMD(data) != RAW_HDR_CMD_DATA) return 0; - /* should be my user id */ - if (RAW_HDR_GET_USR(data) != userid) return 0; - - r -= RAW_HDR_LEN; - datalen = sizeof(buf); - if (uncompress((uint8_t*)buf, &datalen, (uint8_t*) &data[RAW_HDR_LEN], r) == Z_OK) { - write_tun(tun_fd, buf, datalen); - } - return 0; - } -} - - -static int -tunnel_tun(int tun_fd, int dns_fd) -{ - unsigned long outlen; - unsigned long inlen; - char out[64*1024]; - char in[64*1024]; - ssize_t read; - - if ((read = read_tun(tun_fd, in, sizeof(in))) <= 0) - return -1; - - outlen = sizeof(out); - inlen = read; - compress2((uint8_t*)out, &outlen, (uint8_t*)in, inlen, 9); - - memcpy(outpkt.data, out, MIN(outlen, sizeof(outpkt.data))); - outpkt.sentlen = 0; - outpkt.offset = 0; - outpkt.len = outlen; - outpkt.seqno++; - outpkt.fragment = 0; - - if (conn == CONN_DNS_NULL) { - send_chunk(dns_fd); - } else { - send_raw_data(dns_fd); - } - - return read; -} - -static int -tunnel_dns(int tun_fd, int dns_fd) -{ - unsigned long datalen; - char buf[64*1024]; - size_t read; - - if ((read = read_dns(dns_fd, tun_fd, buf, sizeof(buf))) <= 2) - return -1; - - if (downstream_seqno != inpkt.seqno) { - /* New packet */ - inpkt.seqno = downstream_seqno; - inpkt.fragment = downstream_fragment; - inpkt.len = 0; - } else if (downstream_fragment <= inpkt.fragment) { - /* Duplicate fragment */ - return -1; - } - inpkt.fragment = downstream_fragment; - - datalen = MIN(read - 2, sizeof(inpkt.data) - inpkt.len); - - /* Skip 2 byte data header and append to packet */ - memcpy(&inpkt.data[inpkt.len], &buf[2], datalen); - inpkt.len += datalen; - - if (buf[1] & 1) { /* If last fragment flag is set */ - /* Uncompress packet and send to tun */ - datalen = sizeof(buf); - if (uncompress((uint8_t*)buf, &datalen, (uint8_t*) inpkt.data, inpkt.len) == Z_OK) { - write_tun(tun_fd, buf, datalen); - } - inpkt.len = 0; - } - - /* If we have nothing to send, send a ping to get more data */ - if (!is_sending()) - send_ping(dns_fd); - - return read; -} - -static int -tunnel(int tun_fd, int dns_fd) -{ - struct timeval tv; - fd_set fds; - int rv; - int i; - int seconds; - - rv = 0; - seconds = 0; - - while (running) { - tv.tv_sec = 1; - tv.tv_usec = 0; - - - FD_ZERO(&fds); - if ((!is_sending()) || conn == CONN_RAW_UDP) { - FD_SET(tun_fd, &fds); - } - FD_SET(dns_fd, &fds); - - i = select(MAX(tun_fd, dns_fd) + 1, &fds, NULL, NULL, &tv); - - if (running == 0) - break; - - if (i < 0) - err(1, "select"); - - if (i == 0) { /* timeout */ - seconds++; - } else { - if (FD_ISSET(tun_fd, &fds)) { - seconds = 0; - if (tunnel_tun(tun_fd, dns_fd) <= 0) - continue; - } - if (FD_ISSET(dns_fd, &fds)) { - if (tunnel_dns(tun_fd, dns_fd) <= 0) - continue; - } - } - - if (PING_TIMEOUT(seconds)) { - send_ping(dns_fd); - seconds = 0; - } - } - - return rv; -} - -static void -send_raw_data(int dns_fd) -{ - send_raw(dns_fd, outpkt.data, outpkt.len, userid, RAW_HDR_CMD_DATA); -} - -static void -send_chunk(int fd) -{ - char hex[] = "0123456789ABCDEF"; - char buf[4096]; - int avail; - int code; - char *p; - - p = outpkt.data; - p += outpkt.offset; - avail = outpkt.len - outpkt.offset; - - outpkt.sentlen = build_hostname(buf + 4, sizeof(buf) - 4, p, avail, topdomain, dataenc); - - /* Build upstream data header (see doc/proto_xxxxxxxx.txt) */ - - buf[0] = hex[userid & 15]; /* First byte is 4 bits userid */ - - code = ((outpkt.seqno & 7) << 2) | ((outpkt.fragment & 15) >> 2); - buf[1] = b32_5to8(code); /* Second byte is 3 bits seqno, 2 upper bits fragment count */ - - code = ((outpkt.fragment & 3) << 3) | (downstream_seqno & 7); - buf[2] = b32_5to8(code); /* Third byte is 2 bits lower fragment count, 3 bits downstream packet seqno */ - - code = ((downstream_fragment & 15) << 1) | (outpkt.sentlen == avail); - buf[3] = b32_5to8(code); /* Fourth byte is 4 bits downstream fragment count, 1 bit last frag flag */ - - down_ack_seqno = downstream_seqno; - down_ack_fragment = downstream_fragment; - - outpkt.fragment++; - send_query(fd, buf); -} - -static void -send_login(int fd, char *login, int len) -{ - char data[19]; - - memset(data, 0, sizeof(data)); - data[0] = userid; - memcpy(&data[1], login, MIN(len, 16)); - - data[17] = (rand_seed >> 8) & 0xff; - data[18] = (rand_seed >> 0) & 0xff; - - rand_seed++; - - send_packet(fd, 'L', data, sizeof(data)); -} - -static void -send_ping(int fd) -{ - if (conn == CONN_DNS_NULL) { - char data[4]; - - if (is_sending()) { - outpkt.sentlen = 0; - outpkt.offset = 0; - outpkt.len = 0; - } - - data[0] = userid; - data[1] = ((downstream_seqno & 7) << 4) | (downstream_fragment & 15); - data[2] = (rand_seed >> 8) & 0xff; - data[3] = (rand_seed >> 0) & 0xff; - - down_ack_seqno = downstream_seqno; - down_ack_fragment = downstream_fragment; - - rand_seed++; - - send_packet(fd, 'P', data, sizeof(data)); - } else { - send_raw(fd, NULL, 0, userid, RAW_HDR_CMD_PING); - } -} - -static void -send_fragsize_probe(int fd, int fragsize) -{ - char probedata[256]; - char buf[4096]; - - /* build a large query domain which is random and maximum size */ - memset(probedata, MIN(1, rand_seed & 0xff), sizeof(probedata)); - probedata[1] = MIN(1, (rand_seed >> 8) & 0xff); - rand_seed++; - build_hostname(buf + 4, sizeof(buf) - 4, probedata, sizeof(probedata), topdomain, dataenc); - - fragsize &= 2047; - - buf[0] = 'r'; /* Probe downstream fragsize packet */ - buf[1] = b32_5to8((userid << 1) | ((fragsize >> 10) & 1)); - buf[2] = b32_5to8((fragsize >> 5) & 31); - buf[3] = b32_5to8(fragsize & 31); - - send_query(fd, buf); -} - -static void -send_set_downstream_fragsize(int fd, int fragsize) -{ - char data[5]; - - data[0] = userid; - data[1] = (fragsize & 0xff00) >> 8; - data[2] = (fragsize & 0x00ff); - data[3] = (rand_seed >> 8) & 0xff; - data[4] = (rand_seed >> 0) & 0xff; - - rand_seed++; - - send_packet(fd, 'N', data, sizeof(data)); -} - -static void -send_version(int fd, uint32_t version) -{ - char data[6]; - - data[0] = (version >> 24) & 0xff; - data[1] = (version >> 16) & 0xff; - data[2] = (version >> 8) & 0xff; - data[3] = (version >> 0) & 0xff; - - data[4] = (rand_seed >> 8) & 0xff; - data[5] = (rand_seed >> 0) & 0xff; - - rand_seed++; - - send_packet(fd, 'V', data, sizeof(data)); -} - -static void -send_ip_request(int fd, int userid) -{ - char buf[512] = "I____."; - buf[1] = b32_5to8(userid); - - buf[2] = b32_5to8((rand_seed >> 10) & 0x1f); - buf[3] = b32_5to8((rand_seed >> 5) & 0x1f); - buf[4] = b32_5to8((rand_seed ) & 0x1f); - rand_seed++; - - strncat(buf, topdomain, 512 - strlen(buf)); - send_query(fd, buf); -} - -static void -send_raw_udp_login(int dns_fd, int userid, int seed) -{ - char buf[16]; - login_calculate(buf, 16, password, seed + 1); - - send_raw(dns_fd, buf, sizeof(buf), userid, RAW_HDR_CMD_LOGIN); -} - -static void -send_case_check(int fd) -{ - /* The '+' plus character is not allowed according to RFC. - * Expect to get SERVFAIL or similar if it is rejected. - */ - char buf[512] = "zZ+-aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyY1234."; - - strncat(buf, topdomain, 512 - strlen(buf)); - send_query(fd, buf); -} - -static void -send_codec_switch(int fd, int userid, int bits) -{ - char buf[512] = "S_____."; - buf[1] = b32_5to8(userid); - buf[2] = b32_5to8(bits); - - buf[3] = b32_5to8((rand_seed >> 10) & 0x1f); - buf[4] = b32_5to8((rand_seed >> 5) & 0x1f); - buf[5] = b32_5to8((rand_seed ) & 0x1f); - rand_seed++; - - strncat(buf, topdomain, 512 - strlen(buf)); - send_query(fd, buf); -} - -static int -handshake_version(int dns_fd, int *seed) -{ - struct timeval tv; - char in[4096]; - fd_set fds; - uint32_t payload; - int i; - int r; - int read; - - for (i = 0; running && i < 5; i++) { - tv.tv_sec = i + 1; - tv.tv_usec = 0; - - send_version(dns_fd, VERSION); - - FD_ZERO(&fds); - FD_SET(dns_fd, &fds); - - r = select(dns_fd + 1, &fds, NULL, NULL, &tv); - - if(r > 0) { - read = read_dns(dns_fd, 0, in, sizeof(in)); - - if(read <= 0) { - if (read == 0) { - warn("handshake read"); - } - /* if read < 0 then warning has been printed already */ - continue; - } - - if (read >= 9) { - payload = (((in[4] & 0xff) << 24) | - ((in[5] & 0xff) << 16) | - ((in[6] & 0xff) << 8) | - ((in[7] & 0xff))); - - if (strncmp("VACK", in, 4) == 0) { - *seed = payload; - userid = in[8]; - - fprintf(stderr, "Version ok, both using protocol v 0x%08x. You are user #%d\n", VERSION, userid); - return 0; - } else if (strncmp("VNAK", in, 4) == 0) { - warnx("You use protocol v 0x%08x, server uses v 0x%08x. Giving up", - VERSION, payload); - return 1; - } else if (strncmp("VFUL", in, 4) == 0) { - warnx("Server full, all %d slots are taken. Try again later", payload); - return 1; - } - } else - warnx("did not receive proper login challenge"); - } - - fprintf(stderr, "Retrying version check...\n"); - } - warnx("couldn't connect to server"); - return 1; -} - -static int -handshake_login(int dns_fd, int seed) -{ - struct timeval tv; - char in[4096]; - char login[16]; - char server[65]; - char client[65]; - int mtu; - fd_set fds; - int i; - int r; - int read; - - login_calculate(login, 16, password, seed); - - for (i=0; running && i<5 ;i++) { - tv.tv_sec = i + 1; - tv.tv_usec = 0; - - send_login(dns_fd, login, 16); - - FD_ZERO(&fds); - FD_SET(dns_fd, &fds); - - r = select(dns_fd + 1, &fds, NULL, NULL, &tv); - - if(r > 0) { - read = read_dns(dns_fd, 0, in, sizeof(in)); - - if(read <= 0) { - warn("read"); - continue; - } - - if (read > 0) { - int netmask; - if (strncmp("LNAK", in, 4) == 0) { - fprintf(stderr, "Bad password\n"); - return 1; - } else if (sscanf(in, "%64[^-]-%64[^-]-%d-%d", - server, client, &mtu, &netmask) == 4) { - - server[64] = 0; - client[64] = 0; - if (tun_setip(client, netmask) == 0 && - tun_setmtu(mtu) == 0) { - return 0; - } else { - errx(4, "Failed to set IP and MTU"); - } - } else { - fprintf(stderr, "Received bad handshake\n"); - } - } - } - - fprintf(stderr, "Retrying login...\n"); - } - warnx("couldn't login to server"); - return 1; -} - -static int -handshake_raw_udp(int dns_fd, int seed) -{ - struct timeval tv; - char in[4096]; - fd_set fds; - int i; - int r; - int len; - unsigned remoteaddr = 0; - struct in_addr server; - - fprintf(stderr, "Testing raw UDP data to the server (skip with -r)\n"); - for (i=0; running && i<3 ;i++) { - tv.tv_sec = i + 1; - tv.tv_usec = 0; - - send_ip_request(dns_fd, userid); - - FD_ZERO(&fds); - FD_SET(dns_fd, &fds); - - r = select(dns_fd + 1, &fds, NULL, NULL, &tv); - - if(r > 0) { - len = read_dns(dns_fd, 0, in, sizeof(in)); - if (len == 5 && in[0] == 'I') { - /* Received IP address */ - remoteaddr = (in[1] & 0xff); - remoteaddr <<= 8; - remoteaddr |= (in[2] & 0xff); - remoteaddr <<= 8; - remoteaddr |= (in[3] & 0xff); - remoteaddr <<= 8; - remoteaddr |= (in[4] & 0xff); - server.s_addr = ntohl(remoteaddr); - break; - } - } else { - fprintf(stderr, "."); - fflush(stderr); - } - } - - if (!remoteaddr) { - fprintf(stderr, "Failed to get raw server IP, will use DNS mode.\n"); - return 0; - } - fprintf(stderr, "Server is at %s, trying raw login: ", inet_ntoa(server)); - fflush(stderr); - - /* Store address to iodined server */ - memset(&raw_serv, 0, sizeof(raw_serv)); - raw_serv.sin_family = AF_INET; - raw_serv.sin_port = htons(53); - raw_serv.sin_addr = server; - - /* do login against port 53 on remote server - * based on the old seed. If reply received, - * switch to raw udp mode */ - for (i=0; running && i<4 ;i++) { - tv.tv_sec = i + 1; - tv.tv_usec = 0; - - send_raw_udp_login(dns_fd, userid, seed); - - FD_ZERO(&fds); - FD_SET(dns_fd, &fds); - - r = select(dns_fd + 1, &fds, NULL, NULL, &tv); - - if(r > 0) { - /* recv() needed for windows, dont change to read() */ - len = recv(dns_fd, in, sizeof(in), 0); - if (len >= (16 + RAW_HDR_LEN)) { - char hash[16]; - login_calculate(hash, 16, password, seed - 1); - if (memcmp(in, raw_header, RAW_HDR_IDENT_LEN) == 0 - && RAW_HDR_GET_CMD(in) == RAW_HDR_CMD_LOGIN - && memcmp(&in[RAW_HDR_LEN], hash, sizeof(hash)) == 0) { - - fprintf(stderr, "OK\n"); - return 1; - } - } - } - fprintf(stderr, "."); - fflush(stderr); - } - - fprintf(stderr, "failed\n"); - return 0; -} - -static int -handshake_case_check(int dns_fd) -{ - struct timeval tv; - char in[4096]; - fd_set fds; - int i; - int r; - int read; - int case_preserved; - - case_preserved = 0; - for (i=0; running && i<5 ;i++) { - tv.tv_sec = i + 1; - tv.tv_usec = 0; - - send_case_check(dns_fd); - - FD_ZERO(&fds); - FD_SET(dns_fd, &fds); - - r = select(dns_fd + 1, &fds, NULL, NULL, &tv); - - if(r > 0) { - read = read_dns(dns_fd, 0, in, sizeof(in)); - - if (read > 0) { - if (in[0] == 'z' || in[0] == 'Z') { - if (read < (27 * 2)) { - fprintf(stderr, "Received short case check reply. Will use base32 encoder\n"); - return case_preserved; - } else { - int k; - - /* TODO enhance this, base128 is probably also possible */ - case_preserved = 1; - for (k = 0; k < 27 && case_preserved; k += 2) { - if (in[k] == in[k+1]) { - /* test string: zZ+-aAbBcCdDeE... */ - case_preserved = 0; - } - } - return case_preserved; - } - } else { - fprintf(stderr, "Received bad case check reply\n"); - } - } else { - fprintf(stderr, "Got error on case check, will use base32\n"); - return case_preserved; - } - } - - fprintf(stderr, "Retrying case check...\n"); - } - - fprintf(stderr, "No reply on case check, continuing\n"); - return case_preserved; -} - -static void -handshake_switch_codec(int dns_fd) -{ - struct timeval tv; - char in[4096]; - fd_set fds; - int i; - int r; - int read; - - dataenc = get_base64_encoder(); - fprintf(stderr, "Switching to %s codec\n", dataenc->name); - /* Send to server that this user will use base64 from now on */ - for (i=0; running && i<5 ;i++) { - int bits; - tv.tv_sec = i + 1; - tv.tv_usec = 0; - - bits = 6; /* base64 = 6 bits per byte */ - - send_codec_switch(dns_fd, userid, bits); - - FD_ZERO(&fds); - FD_SET(dns_fd, &fds); - - r = select(dns_fd + 1, &fds, NULL, NULL, &tv); - - if(r > 0) { - read = read_dns(dns_fd, 0, in, sizeof(in)); - - if (read > 0) { - if (strncmp("BADLEN", in, 6) == 0) { - fprintf(stderr, "Server got bad message length. "); - goto codec_revert; - } else if (strncmp("BADIP", in, 5) == 0) { - fprintf(stderr, "Server rejected sender IP address. "); - goto codec_revert; - } else if (strncmp("BADCODEC", in, 8) == 0) { - fprintf(stderr, "Server rejected the selected codec. "); - goto codec_revert; - } - in[read] = 0; /* zero terminate */ - fprintf(stderr, "Server switched to codec %s\n", in); - return; - } - } - fprintf(stderr, "Retrying codec switch...\n"); - } - fprintf(stderr, "No reply from server on codec switch. "); - -codec_revert: - fprintf(stderr, "Falling back to base32\n"); - dataenc = get_base32_encoder(); -} - -static int -handshake_autoprobe_fragsize(int dns_fd) -{ - struct timeval tv; - char in[4096]; - fd_set fds; - int i; - int r; - int read; - int proposed_fragsize = 768; - int range = 768; - int max_fragsize = 0; - - max_fragsize = 0; - fprintf(stderr, "Autoprobing max downstream fragment size... (skip with -m fragsize)\n"); - while (running && range > 0 && (range >= 8 || !max_fragsize)) { - for (i=0; running && i<3 ;i++) { - tv.tv_sec = 1; - tv.tv_usec = 0; - send_fragsize_probe(dns_fd, proposed_fragsize); - - FD_ZERO(&fds); - FD_SET(dns_fd, &fds); - - r = select(dns_fd + 1, &fds, NULL, NULL, &tv); - - if(r > 0) { - read = read_dns(dns_fd, 0, in, sizeof(in)); - - if (read > 0) { - /* We got a reply */ - int acked_fragsize = ((in[0] & 0xff) << 8) | (in[1] & 0xff); - if (acked_fragsize == proposed_fragsize) { - if (read == proposed_fragsize) { - fprintf(stderr, "%d ok.. ", acked_fragsize); - fflush(stderr); - max_fragsize = acked_fragsize; - } - } - if (strncmp("BADIP", in, 5) == 0) { - fprintf(stderr, "got BADIP.. "); - fflush(stderr); - } - break; - } - } - fprintf(stderr, "."); - fflush(stderr); - } - range >>= 1; - if (max_fragsize == proposed_fragsize) { - /* Try bigger */ - proposed_fragsize += range; - } else { - /* Try smaller */ - fprintf(stderr, "%d not ok.. ", proposed_fragsize); - fflush(stderr); - proposed_fragsize -= range; - } - } - if (!running) { - fprintf(stderr, "\n"); - warnx("stopped while autodetecting fragment size (Try probing manually with -m)"); - return 0; - } - if (range == 0) { - /* Tried all the way down to 2 and found no good size */ - fprintf(stderr, "\n"); - warnx("found no accepted fragment size. (Try probing manually with -m)"); - return 0; - } - fprintf(stderr, "will use %d\n", max_fragsize); - return max_fragsize; -} - -static void -handshake_set_fragsize(int dns_fd, int fragsize) -{ - struct timeval tv; - char in[4096]; - fd_set fds; - int i; - int r; - int read; - - fprintf(stderr, "Setting downstream fragment size to max %d...\n", fragsize); - for (i=0; running && i<5 ;i++) { - tv.tv_sec = i + 1; - tv.tv_usec = 0; - - send_set_downstream_fragsize(dns_fd, fragsize); - - FD_ZERO(&fds); - FD_SET(dns_fd, &fds); - - r = select(dns_fd + 1, &fds, NULL, NULL, &tv); - - if(r > 0) { - read = read_dns(dns_fd, 0, in, sizeof(in)); - - if (read > 0) { - int accepted_fragsize; - - if (strncmp("BADFRAG", in, 7) == 0) { - fprintf(stderr, "Server rejected fragsize. Keeping default."); - return; - } else if (strncmp("BADIP", in, 5) == 0) { - fprintf(stderr, "Server rejected sender IP address.\n"); - return; - } - - accepted_fragsize = ((in[0] & 0xff) << 8) | (in[1] & 0xff); - return; - } - } - fprintf(stderr, "Retrying set fragsize...\n"); - } - fprintf(stderr, "No reply from server when setting fragsize. Keeping default.\n"); -} - -static int -handshake(int dns_fd, int raw_mode, int autodetect_frag_size, int fragsize) -{ - int seed; - int case_preserved; - int r; - - r = handshake_version(dns_fd, &seed); - if (r) { - return r; - } - - r = handshake_login(dns_fd, seed); - if (r) { - return r; - } - - if (raw_mode && handshake_raw_udp(dns_fd, seed)) { - conn = CONN_RAW_UDP; - } else { - if (raw_mode == 0) { - fprintf(stderr, "Skipping raw mode\n"); - } - case_preserved = handshake_case_check(dns_fd); - - if (case_preserved) { - handshake_switch_codec(dns_fd); - } - - if (autodetect_frag_size) { - fragsize = handshake_autoprobe_fragsize(dns_fd); - if (!fragsize) { - return 1; - } - } - - handshake_set_fragsize(dns_fd, fragsize); - } - - return 0; -} - -static char * -get_resolvconf_addr() -{ - static char addr[16]; - char *rv; -#ifndef WINDOWS32 - char buf[80]; - FILE *fp; - - rv = NULL; - - if ((fp = fopen("/etc/resolv.conf", "r")) == NULL) - err(1, "/etc/resolve.conf"); - - while (feof(fp) == 0) { - fgets(buf, sizeof(buf), fp); - - if (sscanf(buf, "nameserver %15s", addr) == 1) { - rv = addr; - break; - } - } - - fclose(fp); -#else /* !WINDOWS32 */ - FIXED_INFO *fixed_info; - ULONG buflen; - DWORD ret; - - rv = NULL; - fixed_info = malloc(sizeof(FIXED_INFO)); - buflen = sizeof(FIXED_INFO); - - if (GetNetworkParams(fixed_info, &buflen) == ERROR_BUFFER_OVERFLOW) { - /* official ugly api workaround */ - free(fixed_info); - fixed_info = malloc(buflen); - } - - ret = GetNetworkParams(fixed_info, &buflen); - if (ret == NO_ERROR) { - strncpy(addr, fixed_info->DnsServerList.IpAddress.String, sizeof(addr)); - addr[15] = 0; - rv = addr; - } - free(fixed_info); -#endif - return rv; -} - -static void -set_nameserver(const char *cp) -{ - struct in_addr addr; - - if (inet_aton(cp, &addr) != 1) - errx(1, "error parsing nameserver address: '%s'", cp); - - memset(&nameserv, 0, sizeof(nameserv)); - nameserv.sin_family = AF_INET; - nameserv.sin_port = htons(53); - nameserv.sin_addr = addr; + client_stop(); } static void @@ -1204,10 +105,12 @@ int main(int argc, char **argv) { char *nameserv_addr; + char *topdomain; #ifndef WINDOWS32 struct passwd *pw; #endif char *username; + char password[33]; int foreground; char *newroot; char *context; @@ -1221,8 +124,8 @@ main(int argc, char **argv) int retval; int raw_mode; - memset(password, 0, 33); nameserv_addr = NULL; + topdomain = NULL; #ifndef WINDOWS32 pw = NULL; #endif @@ -1231,28 +134,19 @@ main(int argc, char **argv) newroot = NULL; context = NULL; device = NULL; - chunkid = 0; pidfile = NULL; - outpkt.seqno = 0; - inpkt.len = 0; - autodetect_frag_size = 1; max_downstream_frag_size = 3072; - raw_mode = 1; - - b32 = get_base32_encoder(); - dataenc = get_base32_encoder(); - conn = CONN_DNS_NULL; - retval = 0; + raw_mode = 1; #ifdef WINDOWS32 WSAStartup(req_version, &wsa_data); #endif srand((unsigned) time(NULL)); - rand_seed = rand(); + client_init(); #if !defined(BSD) && !defined(__GLIBC__) __progname = strrchr(argv[0], '/'); @@ -1335,7 +229,7 @@ main(int argc, char **argv) } if (nameserv_addr) { - set_nameserver(nameserv_addr); + client_set_nameserver(nameserv_addr); } else { usage(); /* NOTREACHED */ @@ -1353,6 +247,8 @@ main(int argc, char **argv) /* NOTREACHED */ } + client_set_topdomain(topdomain); + if (username != NULL) { #ifndef WINDOWS32 if ((pw = getpwnam(username)) == NULL) { @@ -1365,6 +261,8 @@ main(int argc, char **argv) if (strlen(password) == 0) read_password(password, sizeof(password)); + + client_set_password(password); if ((tun_fd = open_tun(device)) == -1) { retval = 1; @@ -1378,15 +276,15 @@ main(int argc, char **argv) signal(SIGINT, sighandler); signal(SIGTERM, sighandler); - if (handshake(dns_fd, raw_mode, autodetect_frag_size, max_downstream_frag_size)) { + if (client_handshake(dns_fd, raw_mode, autodetect_frag_size, max_downstream_frag_size)) { retval = 1; goto cleanup2; } - if (conn == CONN_DNS_NULL) { + if (client_get_conn() == CONN_DNS_NULL) { fprintf(stderr, "Sending queries for %s to %s\n", topdomain, nameserv_addr); } else { - fprintf(stderr, "Sending raw traffic directly to %s\n", inet_ntoa(raw_serv.sin_addr)); + fprintf(stderr, "Sending raw traffic directly to %s\n", client_get_raw_addr()); } if (foreground == 0) @@ -1413,12 +311,7 @@ main(int argc, char **argv) if (context != NULL) do_setcon(context); - downstream_seqno = 0; - downstream_fragment = 0; - down_ack_seqno = 0; - down_ack_fragment = 0; - - tunnel(tun_fd, dns_fd); + client_tunnel(tun_fd, dns_fd); cleanup2: close_dns(dns_fd); diff --git a/src/login.c b/src/login.c index cce0f31..c8827c3 100644 --- a/src/login.c +++ b/src/login.c @@ -29,7 +29,7 @@ * Needs a 16byte array for output, and 32 bytes password */ void -login_calculate(char *buf, int buflen, char *pass, int seed) +login_calculate(char *buf, int buflen, const char *pass, int seed) { unsigned char temp[32]; md5_state_t ctx; diff --git a/src/login.h b/src/login.h index df49074..840c920 100644 --- a/src/login.h +++ b/src/login.h @@ -17,7 +17,7 @@ #ifndef __LOGIN_H__ #define __LOGIN_H__ -void login_calculate(char *, int, char *, int); +void login_calculate(char *, int, const char *, int); #endif diff --git a/src/util.c b/src/util.c new file mode 100644 index 0000000..70ab90d --- /dev/null +++ b/src/util.c @@ -0,0 +1,69 @@ +/* + * Copyright (c) 2006-2009 Bjorn Andersson , Erik Ekman + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include +#include "common.h" + +char * +get_resolvconf_addr() +{ + static char addr[16]; + char *rv; +#ifndef WINDOWS32 + char buf[80]; + FILE *fp; + + rv = NULL; + + if ((fp = fopen("/etc/resolv.conf", "r")) == NULL) + err(1, "/etc/resolve.conf"); + + while (feof(fp) == 0) { + fgets(buf, sizeof(buf), fp); + + if (sscanf(buf, "nameserver %15s", addr) == 1) { + rv = addr; + break; + } + } + + fclose(fp); +#else /* !WINDOWS32 */ + FIXED_INFO *fixed_info; + ULONG buflen; + DWORD ret; + + rv = NULL; + fixed_info = malloc(sizeof(FIXED_INFO)); + buflen = sizeof(FIXED_INFO); + + if (GetNetworkParams(fixed_info, &buflen) == ERROR_BUFFER_OVERFLOW) { + /* official ugly api workaround */ + free(fixed_info); + fixed_info = malloc(buflen); + } + + ret = GetNetworkParams(fixed_info, &buflen); + if (ret == NO_ERROR) { + strncpy(addr, fixed_info->DnsServerList.IpAddress.String, sizeof(addr)); + addr[15] = 0; + rv = addr; + } + free(fixed_info); +#endif + return rv; +} + diff --git a/src/util.h b/src/util.h new file mode 100644 index 0000000..f514139 --- /dev/null +++ b/src/util.h @@ -0,0 +1,6 @@ +#ifndef __UTIL_H__ +#define __UTIL_H__ + +char *get_resolvconf_addr(); + +#endif