From 002a2c3e1d0f091a48f8cc3eb7dce519870debaf Mon Sep 17 00:00:00 2001 From: Yves Fischer Date: Sat, 11 Jan 2014 18:44:50 +0100 Subject: import code --- jni/iodine/src/client.c | 2527 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2527 insertions(+) create mode 100644 jni/iodine/src/client.c (limited to 'jni/iodine/src/client.c') diff --git a/jni/iodine/src/client.c b/jni/iodine/src/client.c new file mode 100644 index 0000000..552344b --- /dev/null +++ b/jni/iodine/src/client.c @@ -0,0 +1,2527 @@ +/* + * 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 +#define BIND_8_COMPAT +#include +#endif +#include +#include +#include +#endif + +#include "common.h" +#include "encoding.h" +#include "base32.h" +#include "base64.h" +#include "base64u.h" +#include "base128.h" +#include "dns.h" +#include "login.h" +#include "tun.h" +#include "version.h" +#include "client.h" + +static void handshake_lazyoff(int dns_fd); + +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; + +/* Current up/downstream IP packet */ +static struct packet outpkt; +static struct packet inpkt; +int outchunkresent = 0; + +/* My userid at the server */ +static char userid; +static char userid_char; /* used when sending (lowercase) */ +static char userid_char2; /* also accepted when receiving (uppercase) */ + +/* DNS id for next packet */ +static uint16_t chunkid; +static uint16_t chunkid_prev; +static uint16_t chunkid_prev2; + +/* Base32 encoder used for non-data packets and replies */ +static struct encoder *b32; +/* Base64 etc encoders for replies */ +static struct encoder *b64; +static struct encoder *b64u; +static struct encoder *b128; + +/* The encoder used for data packets + * Defaults to Base32, can be changed after handshake */ +static struct encoder *dataenc; + +/* The encoder to use for downstream data */ +static char downenc = ' '; + +/* set query type to send */ +static unsigned short do_qtype = T_UNSET; + +/* My connection mode */ +static enum connection conn; + +static int selecttimeout; /* RFC says timeout minimum 5sec */ +static int lazymode; +static long send_ping_soon; +static time_t lastdownstreamtime; +static long send_query_sendcnt = -1; +static long send_query_recvcnt = 0; +static int hostname_maxlen = 0xFF; + +void +client_init() +{ + running = 1; + b32 = get_base32_encoder(); + b64 = get_base64_encoder(); + b64u = get_base64u_encoder(); + b128 = get_base128_encoder(); + dataenc = get_base32_encoder(); + rand_seed = ((unsigned int) rand()) & 0xFFFF; + send_ping_soon = 1; /* send ping immediately after startup */ + conn = CONN_DNS_NULL; + + chunkid = ((unsigned int) rand()) & 0xFFFF; + chunkid_prev = 0; + chunkid_prev2 = 0; + + outpkt.len = 0; + outpkt.seqno = 0; + outpkt.fragment = 0; + outchunkresent = 0; + inpkt.len = 0; + inpkt.seqno = 0; + inpkt.fragment = 0; +} + +void +client_stop() +{ + running = 0; +} + +enum connection +client_get_conn() +{ + return conn; +} + +void +client_set_nameserver(const char *cp, int port) +{ + struct in_addr addr; + + if (inet_aton(cp, &addr) != 1) { + /* try resolving if a domain is given */ + struct hostent *host; + const char *err; + host = gethostbyname(cp); + if (host != NULL && h_errno > 0) { + int i = 0; + while (host->h_addr_list[i] != 0) { + addr = *(struct in_addr *) host->h_addr_list[i++]; + fprintf(stderr, "Resolved %s to %s\n", cp, inet_ntoa(addr)); + goto setaddr; + } + } +#ifndef WINDOWS32 + err = hstrerror(h_errno); +#else + { + DWORD wserr = WSAGetLastError(); + switch (wserr) { + case WSAHOST_NOT_FOUND: + err = "Host not found"; + break; + case WSANO_DATA: + err = "No data record found"; + break; + default: + err = "Unknown error"; + break; + } + } +#endif /* !WINDOWS32 */ + errx(1, "error resolving nameserver '%s': %s", cp, err); + } + +setaddr: + memset(&nameserv, 0, sizeof(nameserv)); + nameserv.sin_family = AF_INET; + nameserv.sin_port = htons(port); + nameserv.sin_addr = addr; +} + +void +client_set_topdomain(const char *cp) +{ + topdomain = cp; +} + +void +client_set_password(const char *cp) +{ + password = cp; +} + +void +set_qtype(char *qtype) +{ + if (!strcasecmp(qtype, "NULL")) + do_qtype = T_NULL; + else if (!strcasecmp(qtype, "CNAME")) + do_qtype = T_CNAME; + else if (!strcasecmp(qtype, "A")) + do_qtype = T_A; + else if (!strcasecmp(qtype, "MX")) + do_qtype = T_MX; + else if (!strcasecmp(qtype, "SRV")) + do_qtype = T_SRV; + else if (!strcasecmp(qtype, "TXT")) + do_qtype = T_TXT; +} + +char * +get_qtype() +{ + char *c = "UNDEFINED"; + + if (do_qtype == T_NULL) c = "NULL"; + else if (do_qtype == T_CNAME) c = "CNAME"; + else if (do_qtype == T_A) c = "A"; + else if (do_qtype == T_MX) c = "MX"; + else if (do_qtype == T_SRV) c = "SRV"; + else if (do_qtype == T_TXT) c = "TXT"; + + return c; +} + +void +set_downenc(char *encoding) +{ + if (!strcasecmp(encoding, "base32")) + downenc = 'T'; + else if (!strcasecmp(encoding, "base64")) + downenc = 'S'; + else if (!strcasecmp(encoding, "base64u")) + downenc = 'U'; + else if (!strcasecmp(encoding, "base128")) + downenc = 'V'; + else if (!strcasecmp(encoding, "raw")) + downenc = 'R'; +} + +void +client_set_selecttimeout(int select_timeout) +{ + selecttimeout = select_timeout; +} + +void +client_set_lazymode(int lazy_mode) +{ + lazymode = lazy_mode; +} + +void +client_set_hostname_maxlen(int i) +{ + if (i <= 0xFF) + hostname_maxlen = i; +} + +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; + + chunkid_prev2 = chunkid_prev; + chunkid_prev = chunkid; + chunkid += 7727; + if (chunkid == 0) + /* 0 is used as "no-query" in iodined.c */ + chunkid = 7727; + + q.id = chunkid; + q.type = do_qtype; + + len = dns_encode(packet, sizeof(packet), &q, QR_QUERY, hostname, strlen(hostname)); + if (len < 1) { + warnx("dns_encode doesn't fit"); + return; + } + +#if 0 + fprintf(stderr, " Sendquery: id %5d name[0] '%c'\n", q.id, hostname[0]); +#endif + + sendto(fd, packet, len, 0, (struct sockaddr*)&nameserv, sizeof(nameserv)); + + /* There are DNS relays that time out quickly but don't send anything + back on timeout. + And there are relays where, in lazy mode, our new query apparently + _replaces_ our previous query, and we get no answers at all in + lazy mode while legacy immediate-ping-pong works just fine. + Here we detect and fix these situations. + (Can't very well do this anywhere else; this is the only place + we'll reliably get to in such situations.) + */ + + if (send_query_sendcnt >= 0 && send_query_sendcnt < 100 && lazymode) { + send_query_sendcnt++; + + if ((send_query_sendcnt > 6 && send_query_recvcnt <= 0) || + (send_query_sendcnt > 10 && + 4 * send_query_recvcnt < send_query_sendcnt)) { + if (selecttimeout > 1) { + warnx("Receiving too few answers. Setting interval to 1 (-I1)"); + selecttimeout = 1; + /* restart counting */ + send_query_sendcnt = 0; + send_query_recvcnt = 0; + } else if (lazymode) { + warnx("Receiving too few answers. Will try to switch lazy mode off, but that may not always work any more. Start with -L0 next time on this network."); + lazymode = 0; + selecttimeout = 1; + handshake_lazyoff(fd); + } + } + } +} + +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); + outpkt.len = 0; +} + + +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, hostname_maxlen); + send_query(fd, buf); +} + +static inline int +is_sending() +{ + return (outpkt.len != 0); +} + +static void +send_chunk(int fd) +{ + char buf[4096]; + int avail; + int code; + char *p; + static int datacmc = 0; + char *datacmcchars = "abcdefghijklmnopqrstuvwxyz0123456789"; + + p = outpkt.data; + p += outpkt.offset; + avail = outpkt.len - outpkt.offset; + + /* Note: must be same, or smaller than send_fragsize_probe() */ + outpkt.sentlen = build_hostname(buf + 5, sizeof(buf) - 5, p, avail, + topdomain, dataenc, hostname_maxlen); + + /* Build upstream data header (see doc/proto_xxxxxxxx.txt) */ + + buf[0] = userid_char; /* First byte is hex 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) | (inpkt.seqno & 7); + buf[2] = b32_5to8(code); /* Third byte is 2 bits lower fragment count, 3 bits downstream packet seqno */ + + code = ((inpkt.fragment & 15) << 1) | (outpkt.sentlen == avail); + buf[3] = b32_5to8(code); /* Fourth byte is 4 bits downstream fragment count, 1 bit last frag flag */ + + buf[4] = datacmcchars[datacmc]; /* Fifth byte is data-CMC */ + datacmc++; + if (datacmc >= 36) + datacmc = 0; + +#if 0 + fprintf(stderr, " Send: down %d/%d up %d/%d, %d bytes\n", + inpkt.seqno, inpkt.fragment, outpkt.seqno, outpkt.fragment, + outpkt.sentlen); +#endif + + send_query(fd, buf); +} + +static void +send_ping(int fd) +{ + if (conn == CONN_DNS_NULL) { + char data[4]; + + data[0] = userid; + data[1] = ((inpkt.seqno & 7) << 4) | (inpkt.fragment & 15); + data[2] = (rand_seed >> 8) & 0xff; + data[3] = (rand_seed >> 0) & 0xff; + + rand_seed++; + +#if 0 + fprintf(stderr, " Send: down %d/%d (ping)\n", + inpkt.seqno, inpkt.fragment); +#endif + + send_packet(fd, 'p', data, sizeof(data)); + } else { + send_raw(fd, NULL, 0, userid, RAW_HDR_CMD_PING); + } +} + +static void +write_dns_error(struct query *q, int ignore_some_errors) +/* This is called from: + 1. handshake_waitdns() when already checked that reply fits to our + latest query. + 2. tunnel_dns() when already checked that reply is for our ping or data + packet, but not necessarily the most recent (SERVFAIL mostly comes + after long delay). + So ignorable errors are never printed. +*/ +{ + if (!q) return; + + switch (q->rcode) { + case NOERROR: /* 0 */ + if (!ignore_some_errors) + warnx("Got reply without error, but also without question and/or answer"); + break; + case FORMERR: /* 1 */ + warnx("Got FORMERR as reply: server does not understand our request"); + break; + case SERVFAIL: /* 2 */ + if (!ignore_some_errors) + warnx("Got SERVFAIL as reply: server failed or recursion timeout"); + break; + case NXDOMAIN: /* 3 */ + warnx("Got NXDOMAIN as reply: domain does not exist"); + break; + case NOTIMP: /* 4 */ + warnx("Got NOTIMP as reply: server does not support our request"); + break; + case REFUSED: /* 5 */ + warnx("Got REFUSED as reply"); + break; + default: + warnx("Got RCODE %u as reply", q->rcode); + break; + } +} + +static int +dns_namedec(char *outdata, int outdatalen, char *buf, int buflen) +/* Decodes *buf to *outdata. + * *buf WILL be changed by undotify. + * Note: buflen must be _exactly_ strlen(buf) before undotifying. + * (undotify of reduced-len won't copy \0, base-X decode will decode too much.) + * Returns #bytes usefully filled in outdata. + */ +{ + size_t outdatalenu = outdatalen; + + switch (buf[0]) { + case 'h': /* Hostname with base32 */ + case 'H': + /* Need 1 byte H, 3 bytes ".xy", >=1 byte data */ + if (buflen < 5) + return 0; + + /* this also does undotify */ + return unpack_data(outdata, outdatalen, buf + 1, buflen - 4, + b32); + + case 'i': /* Hostname++ with base64 */ + case 'I': + /* Need 1 byte I, 3 bytes ".xy", >=1 byte data */ + if (buflen < 5) + return 0; + + /* this also does undotify */ + return unpack_data(outdata, outdatalen, buf + 1, buflen - 4, + b64); + + case 'j': /* Hostname++ with base64u */ + case 'J': + /* Need 1 byte J, 3 bytes ".xy", >=1 byte data */ + if (buflen < 5) + return 0; + + /* this also does undotify */ + return unpack_data(outdata, outdatalen, buf + 1, buflen - 4, + b64u); + + case 'k': /* Hostname++ with base128 */ + case 'K': + /* Need 1 byte J, 3 bytes ".xy", >=1 byte data */ + if (buflen < 5) + return 0; + + /* this also does undotify */ + return unpack_data(outdata, outdatalen, buf + 1, buflen - 4, + b128); + + case 't': /* plain base32(Thirty-two) from TXT */ + case 'T': + if (buflen < 2) + return 0; + + return b32->decode(outdata, &outdatalenu, buf + 1, buflen - 1); + + case 's': /* plain base64(Sixty-four) from TXT */ + case 'S': + if (buflen < 2) + return 0; + + return b64->decode(outdata, &outdatalenu, buf + 1, buflen - 1); + + case 'u': /* plain base64u (Underscore) from TXT */ + case 'U': + if (buflen < 2) + return 0; + + return b64u->decode(outdata, &outdatalenu, buf + 1, buflen - 1); + + case 'v': /* plain base128 from TXT */ + case 'V': + if (buflen < 2) + return 0; + + return b128->decode(outdata, &outdatalenu, buf + 1, buflen - 1); + + case 'r': /* Raw binary from TXT */ + case 'R': + /* buflen>=1 already checked */ + buflen--; + buflen = MIN(buflen, outdatalen); + memcpy(outdata, buf + 1, buflen); + return buflen; + + default: + warnx("Received unsupported encoding"); + return 0; + } + + /* notreached */ + return 0; +} + +static int +read_dns_withq(int dns_fd, int tun_fd, char *buf, int buflen, struct query *q) +/* FIXME: tun_fd needed for raw handling */ +/* Returns -1 on receive error or decode error, including DNS error replies. + Returns 0 on replies that could be correct but are useless, and are not + DNS error replies. + Returns >0 on correct replies; value is #valid bytes in *buf. +*/ +{ + struct sockaddr_in from; + char data[64*1024]; + socklen_t addrlen; + int r; + + addrlen = sizeof(struct sockaddr); + if ((r = recvfrom(dns_fd, data, sizeof(data), 0, + (struct sockaddr*)&from, &addrlen)) < 0) { + warn("recvfrom"); + return -1; + } + + if (conn == CONN_DNS_NULL) { + int rv; + if (r <= 0) + /* useless packet */ + return 0; + + rv = dns_decode(buf, buflen, q, QR_ANSWER, data, r); + if (rv <= 0) + return rv; + + if (q->type == T_CNAME || q->type == T_TXT) + /* CNAME can also be returned from an A question */ + { + /* + * buf is a hostname or txt stream that we still need to + * decode to binary + * + * also update rv with the number of valid bytes + * + * data is unused here, and will certainly hold the smaller binary + */ + + rv = dns_namedec(data, sizeof(data), buf, rv); + + rv = MIN(rv, buflen); + if (rv > 0) + memcpy(buf, data, rv); + + } else if (q->type == T_MX || q->type == T_SRV) { + /* buf is like "Hname.com\0Hanother.com\0\0" */ + int buftotal = rv; /* idx of last \0 */ + int bufoffset = 0; + int dataoffset = 0; + int thispartlen, dataspace, datanew; + + while (1) { + thispartlen = strlen(buf); + thispartlen = MIN(thispartlen, buftotal-bufoffset); + dataspace = sizeof(data) - dataoffset; + if (thispartlen <= 0 || dataspace <= 0) + break; + + datanew = dns_namedec(data + dataoffset, dataspace, + buf + bufoffset, thispartlen); + if (datanew <= 0) + break; + + bufoffset += thispartlen + 1; + dataoffset += datanew; + } + rv = dataoffset; + rv = MIN(rv, buflen); + if (rv > 0) + memcpy(buf, data, rv); + } + + 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 my user id */ + if (RAW_HDR_GET_USR(data) != userid) return 0; + + if (RAW_HDR_GET_CMD(data) == RAW_HDR_CMD_DATA || + RAW_HDR_GET_CMD(data) == RAW_HDR_CMD_PING) + lastdownstreamtime = time(NULL); + + /* should be data packet */ + if (RAW_HDR_GET_CMD(data) != RAW_HDR_CMD_DATA) 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); + } + + /* don't process any further */ + return 0; + } +} + +static int +handshake_waitdns(int dns_fd, char *buf, int buflen, char c1, char c2, int timeout) +/* Wait for DNS reply fitting to our latest query and returns it. + Returns length of reply = #bytes used in buf. + Returns 0 if fitting reply happens to be useless. + Returns -2 on (at least) DNS error that fits to our latest query, + error message already printed. + Returns -3 on timeout (given in seconds). + Returns -1 on other errors. + + Timeout is restarted when "wrong" (previous/delayed) replies are received, + so effective timeout may be longer than specified. +*/ +{ + struct query q; + int r, rv; + fd_set fds; + struct timeval tv; + + while (1) { + tv.tv_sec = timeout; + tv.tv_usec = 0; + FD_ZERO(&fds); + FD_SET(dns_fd, &fds); + r = select(dns_fd + 1, &fds, NULL, NULL, &tv); + + if (r < 0) + return -1; /* select error */ + if (r == 0) + return -3; /* select timeout */ + + q.id = 0; + q.name[0] = '\0'; + rv = read_dns_withq(dns_fd, 0, buf, buflen, &q); + + if (q.id != chunkid || (q.name[0] != c1 && q.name[0] != c2)) { +#if 0 + fprintf(stderr, "Ignoring unfitting reply id %d starting with '%c'\n", q.id, q.name[0]); +#endif + continue; + } + + /* if still here: reply matches our latest query */ + + /* Non-recursive DNS servers (such as [a-m].root-servers.net) + return no answer, but only additional and authority records. + Can't explicitly test for that here, just assume that + NOERROR is such situation. Only trigger on the very first + requests (Y or V, depending if -T given). + */ + if (rv < 0 && q.rcode == NOERROR && + (q.name[0] == 'Y' || q.name[0] == 'y' || + q.name[0] == 'V' || q.name[0] == 'v')) { + fprintf(stderr, "Got empty reply. This nameserver may not be resolving recursively, use another.\n"); + fprintf(stderr, "Try \"iodine [options] ns.%s %s\" first, it might just work.\n", + topdomain, topdomain); + return -2; + } + + /* If we get an immediate SERVFAIL on the handshake query + we're waiting for, wait a while before sending the next. + SERVFAIL reliably happens during fragsize autoprobe, but + mostly long after we've moved along to some other queries. + However, some DNS relays, once they throw a SERVFAIL, will + for several seconds apply it immediately to _any_ new query + for the same topdomain. When this happens, waiting a while + is the only option that works. + */ + if (rv < 0 && q.rcode == SERVFAIL) + sleep(1); + + if (rv < 0) { + write_dns_error(&q, 1); + return -2; + } + /* rv either 0 or >0, return it as is. */ + return rv; + } + + /* not reached */ + return -1; +} + +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; + + /* We may be here only to empty the tun device; then return -1 + to force continue in select loop. */ + if (is_sending()) + 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.seqno = (outpkt.seqno + 1) & 7; + outpkt.len = outlen; + outpkt.fragment = 0; + outchunkresent = 0; + + if (conn == CONN_DNS_NULL) { + send_chunk(dns_fd); + + send_ping_soon = 0; + } else { + send_raw_data(dns_fd); + } + + return read; +} + +static int +tunnel_dns(int tun_fd, int dns_fd) +{ + static long packrecv = 0; + static long packrecv_oos = 0; + static long packrecv_servfail = 0; + int up_ack_seqno; + int up_ack_fragment; + int new_down_seqno; + int new_down_fragment; + struct query q; + unsigned long datalen; + char buf[64*1024]; + int read; + int send_something_now = 0; + + memset(q.name, 0, sizeof(q.name)); + read = read_dns_withq(dns_fd, tun_fd, buf, sizeof(buf), &q); + + if (conn != CONN_DNS_NULL) + return 1; /* everything already done */ + +#if 0 + fprintf(stderr, " Recv: id %5d name[0]='%c'\n", + q.id, q.name[0]); +#endif + + /* Don't process anything that isn't data for us; usually error + replies from fragsize probes etc. However a sequence of those, + mostly 1 sec apart, will continuously break the >=2-second select + timeout, which means we won't send a proper ping for a while. + So make select a bit faster, <1sec. */ + if (q.name[0] != 'P' && q.name[0] != 'p' && + q.name[0] != userid_char && q.name[0] != userid_char2) { + send_ping_soon = 700; + return -1; /* nothing done */ + } + + if (read < 2) { + /* Maybe SERVFAIL etc. Send ping to get things back in order, + but wait a bit to prevent fast ping-pong loops. */ + + if (read < 0) + write_dns_error(&q, 0); + + if (read < 0 && q.rcode == SERVFAIL && lazymode && + selecttimeout > 1) { + if (packrecv < 500 && packrecv_servfail < 4) { + packrecv_servfail++; + warnx("Hmm, that's %ld. Your data should still go through...", packrecv_servfail); + } else if (packrecv < 500 && packrecv_servfail == 4) { + packrecv_servfail++; + warnx("I think %ld is too many. Setting interval to 1 to hopefully reduce SERVFAILs. But just ignore them if data still comes through. (Use -I1 next time on this network.)", packrecv_servfail); + selecttimeout = 1; + send_query_sendcnt = 0; + send_query_recvcnt = 0; + } else if (packrecv >= 500 && packrecv_servfail > 0) { + warnx("(Sorry, stopped counting; try -I1 if you experience hiccups.)"); + packrecv_servfail = 0; + } + } + + /* read==1 happens with "QMEM" illegal replies, caused by + heavy reordering, or after short disconnections when + data-CMC has looped around into the "duplicate" values. + All these cases are helped by faster pinging. */ +#if 0 + if (read == 1) + fprintf(stderr, " q=%c id %5d 1-byte illegal \"QMEM\" reply\n", q.name[0], q.id); +#endif + + send_ping_soon = 900; + return -1; /* nothing done */ + } + + if (read == 5 && !strncmp("BADIP", buf, 5)) { + warnx("BADIP: Server rejected sender IP address (maybe iodined -c will help), or server kicked us due to timeout. Will exit if no downstream data is received in 60 seconds."); + return -1; /* nothing done */ + } + + if (send_ping_soon) { + send_something_now = 1; + send_ping_soon = 0; + } + + /* Decode the data header, update seqno and frag; + already checked read>=2 + Note that buf[] gets overwritten when down-pkt complete */ + new_down_seqno = (buf[1] >> 5) & 7; + new_down_fragment = (buf[1] >> 1) & 15; + up_ack_seqno = (buf[0] >> 4) & 7; + up_ack_fragment = buf[0] & 15; + +#if 0 + fprintf(stderr, " Recv: id %5d down %d/%d up %d/%d, %d bytes\n", + q.id, new_down_seqno, new_down_fragment, up_ack_seqno, + up_ack_fragment, read); +#endif + + /* Downstream data traffic */ + + if (read > 2 && new_down_seqno != inpkt.seqno && + recent_seqno(inpkt.seqno, new_down_seqno)) { + /* This is the previous seqno, or a bit earlier. + Probably out-of-sequence dupe due to unreliable + intermediary DNS. Don't get distracted, but send + ping quickly to get things back in order. + Ping will send our current seqno idea. + If it's really a new packet that skipped multiple seqnos + (why??), server will re-send and drop a few times and + eventually everything will work again. */ + read = 2; + send_ping_soon = 500; + /* Still process upstream ack, if any */ + } + + if (!(packrecv & 0x1000000)) + packrecv++; + send_query_recvcnt++; /* overflow doesn't matter */ + + /* Don't process any non-recent stuff any further. + No need to remember more than 3 ids: in practice any older replies + arrive after new/current replies, and whatever data the old replies + have, it has become useless in the mean time. + Actually, ever since iodined is replying to both the original query + and the last dupe, this hardly triggers any more. + */ + if (q.id != chunkid && q.id != chunkid_prev && q.id != chunkid_prev2) { + packrecv_oos++; +#if 0 + fprintf(stderr, " q=%c Packs received = %8ld Out-of-sequence = %8ld\n", q.name[0], packrecv, packrecv_oos); +#endif + if (lazymode && packrecv < 1000 && packrecv_oos == 5) { + if (selecttimeout > 1) + warnx("Hmm, getting some out-of-sequence DNS replies. Setting interval to 1 (use -I1 next time on this network). If data traffic still has large hiccups, try if -L0 works better."); + else + warnx("Hmm, getting some out-of-sequence DNS replies. If data traffic often has large hiccups, try running with -L0 ."); + selecttimeout = 1; + send_query_sendcnt = 0; + send_query_recvcnt = 0; + } + + if (send_something_now) { + send_ping(dns_fd); + send_ping_soon = 0; + } + return -1; /* nothing done */ + } +#if 0 + fprintf(stderr, " q=%c Packs received = %8ld Out-of-sequence = %8ld\n", q.name[0], packrecv, packrecv_oos); +#endif + + /* Okay, we have a recent downstream packet */ + lastdownstreamtime = time(NULL); + + /* In lazy mode, we shouldn't get much replies to our most-recent + query, only during heavy data transfer. Since this means the server + doesn't have any packets left, send one relatively fast (but not + too fast, to avoid runaway ping-pong loops..) */ + if (q.id == chunkid && lazymode) { + if (!send_ping_soon || send_ping_soon > 900) + send_ping_soon = 900; + } + + if (read == 2 && new_down_seqno != inpkt.seqno && + !recent_seqno(inpkt.seqno, new_down_seqno)) { + /* This is a seqno that we didn't see yet, but it has + no data any more. Possible since iodined will send + fitting packs just once and not wait for ack. + Real data got lost, or will arrive shortly. + Update our idea of the seqno, and drop any waiting + old pack. Send ping to get things back on track. */ + inpkt.seqno = new_down_seqno; + inpkt.fragment = new_down_fragment; + inpkt.len = 0; + send_ping_soon = 500; + } + + while (read > 2) { + /* "if" with easy exit */ + + if (new_down_seqno != inpkt.seqno) { + /* New packet (and not dupe of recent; checked above) */ + /* Forget any old packet, even if incomplete */ + inpkt.seqno = new_down_seqno; + inpkt.fragment = new_down_fragment; /* hopefully 0 */ + inpkt.len = 0; + } else if (inpkt.fragment == 0 && new_down_fragment == 0 && + inpkt.len == 0) { + /* Weird situation: we probably got a no-data reply + for this seqno (see above), and the actual data + is following now. */ + /* okay, nothing to do here, just so that next else-if + doesn't trigger */ + } else if (new_down_fragment <= inpkt.fragment) { + /* Same packet but duplicate fragment, ignore. + If the server didn't get our ack for it, the next + ping or chunk will do that. */ + send_ping_soon = 500; + break; + } else if (new_down_fragment > inpkt.fragment + 1) { + /* Quite impossible. We missed a fragment, but the + server got our ack for it and is sending the next + fragment already. Don't handle it but let server + re-send and drop. */ + send_ping_soon = 500; + break; + } + inpkt.fragment = new_down_fragment; + + datalen = MIN(read - 2, sizeof(inpkt.data) - inpkt.len); + + /* we are here only when read > 2, so datalen "always" >=1 */ + + /* 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 */ + /* RE-USES buf[] */ + 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; + /* Keep .seqno and .fragment as is, so that we won't + reassemble from duplicate fragments */ + } + + /* Send anything to ack the received seqno/frag, and get more */ + if (inpkt.len == 0) { + /* was last frag; wait just a trifle because our + tun will probably return TCP-ack immediately. + 5msec = 200 DNSreq/sec */ + send_ping_soon = 5; + } else { + /* server certainly has more data */ + send_something_now = 1; + } + + break; + } + + /* NOTE: buf[] was overwritten when down-packet complete */ + + + /* Upstream data traffic */ + + if (is_sending()) { + /* already checked read>=2 */ +#if 0 + fprintf(stderr, "Got ack for %d,%d - expecting %d,%d - id=%d cur=%d prev=%d prev2=%d\n", + up_ack_seqno, up_ack_fragment, outpkt.seqno, outpkt.fragment, + q.id, chunkid, chunkid_prev, chunkid_prev2); +#endif + + if (up_ack_seqno == outpkt.seqno && + up_ack_fragment == outpkt.fragment) { + /* Okay, previously sent fragment has arrived */ + + outpkt.offset += outpkt.sentlen; + if (outpkt.offset >= outpkt.len) { + /* Packet completed */ + outpkt.offset = 0; + outpkt.len = 0; + outpkt.sentlen = 0; + outchunkresent = 0; + + /* Normally, server still has a query in queue, + but sometimes not. So send a ping. + (Comment this out and you'll see occasional + hiccups.) + But since the server often still has a + query and we can expect a TCP-ack returned + from our tun device quickly in many cases, + don't be too fast. + 20msec still is 50 DNSreq/second... */ + if (!send_ping_soon || send_ping_soon > 20) + send_ping_soon = 20; + } else { + /* More to send */ + outpkt.fragment++; + outchunkresent = 0; + send_chunk(dns_fd); + send_ping_soon = 0; + send_something_now = 0; + } + } + /* else: Some wrong fragment has arrived, or old fragment is + acked again, mostly by ping responses. + Don't resend chunk, usually not needed; select loop will + re-send on timeout (1sec if is_sending()). */ + } + + + /* Send ping if we didn't send anything yet */ + if (send_something_now) { + send_ping(dns_fd); + send_ping_soon = 0; + } + + return read; +} + +static int +always_1() +{ + return 1; +} + +int +client_tunnel(int tun_fd, int dns_fd) +{ + return client_tunnel_cb(tun_fd, dns_fd, &always_1); +} + +int +client_tunnel_cb(int tun_fd, int dns_fd, int + (*cb_ask_continue)()) +{ + struct timeval tv; + fd_set fds; + int rv; + int i; + + rv = 0; + lastdownstreamtime = time(NULL); + send_query_sendcnt = 0; /* start counting now */ + + while (running && cb_ask_continue()) { + tv.tv_sec = selecttimeout; + tv.tv_usec = 0; + + if (is_sending()) { + /* fast timeout for retransmits */ + tv.tv_sec = 1; + tv.tv_usec = 0; + } + + if (send_ping_soon) { + tv.tv_sec = 0; + tv.tv_usec = send_ping_soon * 1000; + } + + FD_ZERO(&fds); + if (!is_sending() || outchunkresent >= 2) { + /* If re-sending upstream data, chances are that + we're several seconds behind already and TCP + will start filling tun buffer with (useless) + retransmits. + Get up-to-date fast by simply dropping stuff, + that's what TCP is designed to handle. */ + FD_SET(tun_fd, &fds); + } + FD_SET(dns_fd, &fds); + + i = select(MAX(tun_fd, dns_fd) + 1, &fds, NULL, NULL, &tv); + + if (lastdownstreamtime + 60 < time(NULL)) { + warnx("No downstream data received in 60 seconds, shutting down."); + running = 0; + } + + if (running == 0) + break; + + if (i < 0) + err(1, "select"); + + if (i == 0) { + /* timeout */ + if (is_sending()) { + /* Re-send current fragment; either frag + or ack probably dropped somewhere. + But problem: no cache-miss-counter, + so hostname will be identical. + Just drop whole packet after 3 retries, + and TCP retransmit will solve it. + NOTE: tun dropping above should be + >=(value_here - 1) */ + if (outchunkresent < 3) { + outchunkresent++; + send_chunk(dns_fd); + } else { + outpkt.offset = 0; + outpkt.len = 0; + outpkt.sentlen = 0; + outchunkresent = 0; + + send_ping(dns_fd); + } + } else { + send_ping(dns_fd); + } + send_ping_soon = 0; + + } else { + + if (FD_ISSET(tun_fd, &fds)) { + if (tunnel_tun(tun_fd, dns_fd) <= 0) + continue; + /* Returns -1 on error OR when quickly + dropping data in case of DNS congestion; + we need to _not_ do tunnel_dns() then. + If chunk sent, sets send_ping_soon=0. */ + } + if (FD_ISSET(dns_fd, &fds)) { + if (tunnel_dns(tun_fd, dns_fd) <= 0) + continue; + } + } + } + + 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, + * will also take up maximal space in the return packet + */ + memset(probedata, MAX(1, rand_seed & 0xff), sizeof(probedata)); + probedata[1] = MAX(1, (rand_seed >> 8) & 0xff); + rand_seed++; + + /* Note: must either be same, or larger, than send_chunk() */ + build_hostname(buf + 5, sizeof(buf) - 5, probedata, sizeof(probedata), + topdomain, dataenc, hostname_maxlen); + + 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); + buf[4] = 'd'; /* dummy to match send_chunk() */ + + 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_upenctest(int fd, char *s) +/* NOTE: String may be at most 63-4=59 chars to fit in 1 dns chunk. */ +{ + char buf[512] = "z___"; + + buf[1] = b32_5to8((rand_seed >> 10) & 0x1f); + buf[2] = b32_5to8((rand_seed >> 5) & 0x1f); + buf[3] = b32_5to8((rand_seed ) & 0x1f); + rand_seed++; + + strncat(buf, s, 512); + strncat(buf, ".", 512); + strncat(buf, topdomain, 512 - strlen(buf)); + send_query(fd, buf); +} + +static void +send_downenctest(int fd, char downenc, int variant, char *s, int slen) +/* Note: content/handling of s is not defined yet. */ +{ + char buf[512] = "y_____."; + + buf[1] = tolower(downenc); + buf[2] = b32_5to8(variant); + + 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 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 void +send_downenc_switch(int fd, int userid) +{ + char buf[512] = "o_____."; + buf[1] = b32_5to8(userid); + buf[2] = tolower(downenc); + + 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 void +send_lazy_switch(int fd, int userid) +{ + char buf[512] = "o_____."; + buf[1] = b32_5to8(userid); + + if (lazymode) + buf[2] = 'l'; + else + buf[2] = 'i'; + + 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) +{ + char hex[] = "0123456789abcdef"; + char hex2[] = "0123456789ABCDEF"; + char in[4096]; + uint32_t payload; + int i; + int read; + + for (i = 0; running && i < 5; i++) { + + send_version(dns_fd, VERSION); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'v', 'V', i+1); + + /*XXX START adjust indent 1 tab back*/ + 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]; + userid_char = hex[userid & 15]; + userid_char2 = hex2[userid & 15]; + + 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 if (read > 0) + warnx("did not receive proper login challenge"); + /*XXX END adjust indent 1 tab back*/ + + fprintf(stderr, "Retrying version check...\n"); + } + warnx("couldn't connect to server (maybe other -T options will work)"); + return 1; +} + +static int +handshake_login(int dns_fd, int seed) +{ + char in[4096]; + char login[16]; + char server[65]; + char client[65]; + int mtu; + int i; + int read; + + login_calculate(login, 16, password, seed); + + for (i=0; running && i<5 ;i++) { + + send_login(dns_fd, login, 16); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'l', 'L', i+1); + + /*XXX START adjust indent 1 tab back*/ + 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, server, netmask) == 0 && + tun_setmtu(mtu) == 0) { + + fprintf(stderr, "Server tunnel IP is %s\n", server); + return 0; + } else { + errx(4, "Failed to set IP and MTU"); + } + } else { + fprintf(stderr, "Received bad handshake\n"); + } + } + /*XXX END adjust indent 1 tab back*/ + + 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)"); + for (i=0; running && i<3 ;i++) { + + send_ip_request(dns_fd, userid); + + len = handshake_waitdns(dns_fd, in, sizeof(in), 'i', 'I', i+1); + + /*XXX START adjust indent 1 tab back*/ + 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; + } + /*XXX END adjust indent 1 tab back*/ + + fprintf(stderr, "."); + fflush(stderr); + } + fprintf(stderr, "\n"); + if (!running) + return 0; + + 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_upenctest(int dns_fd, char *s) +/* NOTE: *s may be max 59 chars; must start with "aA" for case-swap check + Returns: + -1: case swap, no need for any further test: error printed; or Ctrl-C + 0: not identical or error or timeout + 1: identical string returned +*/ +{ + char in[4096]; + unsigned char *uin = (unsigned char *) in; + unsigned char *us = (unsigned char *) s; + int i; + int read; + int slen; + + slen = strlen(s); + for (i=0; running && i<3 ;i++) { + + send_upenctest(dns_fd, s); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'z', 'Z', i+1); + + if (read == -2) + return 0; /* hard error */ + + if (read > 0 && read < slen + 4) + return 0; /* reply too short (chars dropped) */ + + if (read > 0) { + int k; +#if 0 + /* in[56] = '@'; */ + /* in[56] = '_'; */ + /* if (in[29] == '\344') in[29] = 'a'; */ + in[read] = '\0'; + fprintf(stderr, "BounceReply: >%s<\n", in); +#endif + /* quick check if case swapped, to give informative error msg */ + if (in[4] == 'A') { + fprintf(stderr, "DNS queries get changed to uppercase, keeping upstream codec Base32\n"); + return -1; + } + if (in[5] == 'a') { + fprintf(stderr, "DNS queries get changed to lowercase, keeping upstream codec Base32\n"); + return -1; + } + + for (k = 0; k < slen; k++) { + if (in[k+4] != s[k]) { + /* Definitely not reliable */ + if (in[k+4] >= ' ' && in[k+4] <= '~' && + s[k] >= ' ' && s[k] <= '~') { + fprintf(stderr, "DNS query char '%c' gets changed into '%c'\n", + s[k], in[k+4]); + } else { + fprintf(stderr, "DNS query char 0x%02X gets changed into 0x%02X\n", + (unsigned int) us[k], + (unsigned int) uin[k+4]); + } + return 0; + } + } + /* if still here, then all okay */ + return 1; + } + + fprintf(stderr, "Retrying upstream codec test...\n"); + } + + if (!running) + return -1; + + /* timeout */ + return 0; +} + +static int +handshake_upenc_autodetect(int dns_fd) +/* Returns: + 0: keep Base32 + 1: Base64 is okay + 2: Base64u is okay + 3: Base128 is okay +*/ +{ + /* Note: max 59 chars, must start with "aA". + pat64: If 0129 work, assume 3-8 are okay too. + + RFC1035 par 2.3.1 states that [A-Z0-9-] allowed, but only + [A-Z] as first, and [A-Z0-9] as last char _per label_. + Test by having '-' as last char. + */ + char *pat64="aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ+0129-"; + char *pat64u="aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ_0129-"; + char *pat128a="aA-Aaahhh-Drink-mal-ein-J\344germeister-"; + char *pat128b="aA-La-fl\373te-na\357ve-fran\347aise-est-retir\351-\340-Cr\350te"; + char *pat128c="aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ"; + char *pat128d="aA0123456789\274\275\276\277" + "\300\301\302\303\304\305\306\307\310\311\312\313\314\315\316\317"; + char *pat128e="aA" + "\320\321\322\323\324\325\326\327\330\331\332\333\334\335\336\337" + "\340\341\342\343\344\345\346\347\350\351\352\353\354\355\356\357" + "\360\361\362\363\364\365\366\367\370\371\372\373\374\375"; + int res; + + /* Try Base128, starting very gently to not draw attention */ + while (1) { + res = handshake_upenctest(dns_fd, pat128a); + if (res < 0) { + /* DNS swaps case, msg already printed; or Ctrl-C */ + return 0; + } else if (res == 0) { + /* Probably not okay, skip Base128 entirely */ + break; + } + + res = handshake_upenctest(dns_fd, pat128b); + if (res < 0) + return 0; + else if (res == 0) + break; + + /* if this works, we can test the real stuff */ + + res = handshake_upenctest(dns_fd, pat128c); + if (res < 0) + return 0; + else if (res == 0) + break; + + res = handshake_upenctest(dns_fd, pat128d); + if (res < 0) + return 0; + else if (res == 0) + break; + + res = handshake_upenctest(dns_fd, pat128e); + if (res < 0) + return 0; + else if (res == 0) + break; + + /* if still here, then base128 works completely */ + return 3; + } + + /* Try Base64 (with plus sign) */ + res = handshake_upenctest(dns_fd, pat64); + if (res < 0) { + /* DNS swaps case, msg already printed; or Ctrl-C */ + return 0; + } else if (res > 0) { + /* All okay, Base64 msg will be printed later */ + return 1; + } + + /* Try Base64u (with _u_nderscore) */ + res = handshake_upenctest(dns_fd, pat64u); + if (res < 0) { + /* DNS swaps case, msg already printed; or Ctrl-C */ + return 0; + } else if (res > 0) { + /* All okay, Base64u msg will be printed later */ + return 2; + } + + /* if here, then nonthing worked */ + fprintf(stderr, "Keeping upstream codec Base32\n"); + return 0; +} + +static int +handshake_downenctest(int dns_fd, char trycodec) +/* Returns: + 0: not identical or error or timeout + 1: identical string returned +*/ +{ + char in[4096]; + int i; + int read; + char *s = DOWNCODECCHECK1; + int slen = DOWNCODECCHECK1_LEN; + + for (i=0; running && i<3 ;i++) { + + send_downenctest(dns_fd, trycodec, 1, NULL, 0); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'y', 'Y', i+1); + + if (read == -2) + return 0; /* hard error */ + + if (read > 0 && read != slen) + return 0; /* reply incorrect = unreliable */ + + if (read > 0) { + int k; + for (k = 0; k < slen; k++) { + if (in[k] != s[k]) { + /* Definitely not reliable */ + return 0; + } + } + /* if still here, then all okay */ + return 1; + } + + fprintf(stderr, "Retrying downstream codec test...\n"); + } + + /* timeout */ + return 0; +} + +static char +handshake_downenc_autodetect(int dns_fd) +/* Returns codec char (or ' ' if no advanced codec works) */ +{ + int base64ok = 0; + int base64uok = 0; + int base128ok = 0; + + if (do_qtype == T_NULL) { + /* no other choice than raw */ + fprintf(stderr, "No alternative downstream codec available, using default (Raw)\n"); + return ' '; + } + + fprintf(stderr, "Autodetecting downstream codec (use -O to override)\n"); + + /* Try Base64 */ + if (handshake_downenctest(dns_fd, 'S')) + base64ok = 1; + else if (running && handshake_downenctest(dns_fd, 'U')) + base64uok = 1; + + /* Try Base128 only if 64 gives us some perspective */ + if (running && (base64ok || base64uok)) { + if (handshake_downenctest(dns_fd, 'V')) + base128ok = 1; + } + + /* If 128 works, then TXT may give us Raw as well */ + if (running && (base128ok && do_qtype == T_TXT)) { + if (handshake_downenctest(dns_fd, 'R')) + return 'R'; + } + + if (!running) + return ' '; + + if (base128ok) + return 'V'; + if (base64ok) + return 'S'; + if (base64uok) + return 'U'; + + fprintf(stderr, "No advanced downstream codecs seem to work, using default (Base32)\n"); + return ' '; +} + +static int +handshake_qtypetest(int dns_fd, int timeout) +/* Returns: + 0: doesn't work with this timeout + 1: works properly +*/ +{ + char in[4096]; + int read; + char *s = DOWNCODECCHECK1; + int slen = DOWNCODECCHECK1_LEN; + int trycodec; + int k; + + if (do_qtype == T_NULL) + trycodec = 'R'; + else + trycodec = 'T'; + + /* We could use 'Z' bouncing here, but 'Y' also tests that 0-255 + byte values can be returned, which is needed for NULL to work. */ + + send_downenctest(dns_fd, trycodec, 1, NULL, 0); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'y', 'Y', timeout); + + if (read != slen) + return 0; /* incorrect */ + + for (k = 0; k < slen; k++) { + if (in[k] != s[k]) { + /* corrupted */ + return 0; + } + } + + /* if still here, then all okay */ + return 1; +} + +static int +handshake_qtype_numcvt(int num) +{ + switch (num) { + case 0: return T_NULL; + case 1: return T_TXT; + case 2: return T_SRV; + case 3: return T_MX; + case 4: return T_CNAME; + case 5: return T_A; + } + return T_UNSET; +} + +static int +handshake_qtype_autodetect(int dns_fd) +/* Returns: + 0: okay, do_qtype set + 1: problem, program exit +*/ +{ + int highestworking = 100; + int timeout; + int qtypenum; + + fprintf(stderr, "Autodetecting DNS query type (use -T to override)"); + fflush(stderr); + + /* Method: try all "interesting" qtypes with a 1-sec timeout, then try + all "still-interesting" qtypes with a 2-sec timeout, etc. + "Interesting" means: qtypes that (are expected to) have higher + bandwidth than what we know is working already (highestworking). + + Note that DNS relays may not immediately resolve the first (NULL) + query in 1 sec, due to long recursive lookups, so we keep trying + to see if things will start working after a while. + */ + + for (timeout = 1; running && timeout <= 3; timeout++) { + for (qtypenum = 0; running && qtypenum < highestworking; qtypenum++) { + do_qtype = handshake_qtype_numcvt(qtypenum); + if (do_qtype == T_UNSET) + break; /* this round finished */ + + fprintf(stderr, "."); + fflush(stderr); + + if (handshake_qtypetest(dns_fd, timeout)) { + /* okay */ + highestworking = qtypenum; +#if 0 + fprintf(stderr, " Type %s timeout %d works\n", + get_qtype(), timeout); +#endif + break; + /* try others with longer timeout */ + } + /* else: try next qtype with same timeout */ + } + if (highestworking == 0) + /* good, we have NULL; abort immediately */ + break; + } + + fprintf(stderr, "\n"); + + if (!running) { + warnx("Stopped while autodetecting DNS query type (try setting manually with -T)"); + return 1; /* problem */ + } + + /* finished */ + do_qtype = handshake_qtype_numcvt(highestworking); + + if (do_qtype == T_UNSET) { + /* also catches highestworking still 100 */ + warnx("No suitable DNS query type found. Are you connected to a network?"); + warnx("If you expect very long roundtrip delays, use -T explicitly."); + warnx("(Also, connecting to an \"ancient\" version of iodined won't work.)"); + return 1; /* problem */ + } + + /* "using qtype" message printed in handshake function */ + return 0; /* okay */ +} + +static int +handshake_edns0_check(int dns_fd) +/* Returns: + 0: EDNS0 not supported; or Ctrl-C + 1: EDNS0 works +*/ +{ + char in[4096]; + int i; + int read; + char *s = DOWNCODECCHECK1; + int slen = DOWNCODECCHECK1_LEN; + char trycodec; + + if (do_qtype == T_NULL) + trycodec = 'R'; + else + trycodec = 'T'; + + for (i=0; running && i<3 ;i++) { + + send_downenctest(dns_fd, trycodec, 1, NULL, 0); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'y', 'Y', i+1); + + if (read == -2) + return 0; /* hard error */ + + if (read > 0 && read != slen) + return 0; /* reply incorrect = unreliable */ + + if (read > 0) { + int k; + for (k = 0; k < slen; k++) { + if (in[k] != s[k]) { + /* Definitely not reliable */ + return 0; + } + } + /* if still here, then all okay */ + return 1; + } + + fprintf(stderr, "Retrying EDNS0 support test...\n"); + } + + /* timeout or Ctrl-C */ + return 0; +} + +static void +handshake_switch_codec(int dns_fd, int bits) +{ + char in[4096]; + int i; + int read; + struct encoder *tempenc; + + if (bits == 5) + tempenc = get_base32_encoder(); + else if (bits == 6) + tempenc = get_base64_encoder(); + else if (bits == 26) /* "2nd" 6 bits per byte, with underscore */ + tempenc = get_base64u_encoder(); + else if (bits == 7) + tempenc = get_base128_encoder(); + else return; + + fprintf(stderr, "Switching upstream to codec %s\n", tempenc->name); + + for (i=0; running && i<5 ;i++) { + + send_codec_switch(dns_fd, userid, bits); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 's', 'S', i+1); + + /*XXX START adjust indent 1 tab back*/ + 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 upstream to codec %s\n", in); + dataenc = tempenc; + return; + } + /*XXX END adjust indent 1 tab back*/ + + fprintf(stderr, "Retrying codec switch...\n"); + } + if (!running) + return; + + fprintf(stderr, "No reply from server on codec switch. "); + +codec_revert: + fprintf(stderr, "Falling back to upstream codec %s\n", dataenc->name); +} + +static void +handshake_switch_downenc(int dns_fd) +{ + char in[4096]; + int i; + int read; + char *dname; + + dname = "Base32"; + if (downenc == 'S') + dname = "Base64"; + else if (downenc == 'U') + dname = "Base64u"; + else if (downenc == 'V') + dname = "Base128"; + else if (downenc == 'R') + dname = "Raw"; + + fprintf(stderr, "Switching downstream to codec %s\n", dname); + for (i=0; running && i<5 ;i++) { + + send_downenc_switch(dns_fd, userid); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'o', 'O', i+1); + + /*XXX START adjust indent 1 tab back*/ + 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 downstream to codec %s\n", in); + return; + } + /*XXX END adjust indent 1 tab back*/ + + fprintf(stderr, "Retrying codec switch...\n"); + } + if (!running) + return; + + fprintf(stderr, "No reply from server on codec switch. "); + +codec_revert: + fprintf(stderr, "Falling back to downstream codec Base32\n"); +} + +static void +handshake_try_lazy(int dns_fd) +{ + char in[4096]; + int i; + int read; + + fprintf(stderr, "Switching to lazy mode for low-latency\n"); + for (i=0; running && i<5; i++) { + + send_lazy_switch(dns_fd, userid); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'o', 'O', i+1); + + /*XXX START adjust indent 1 tab back*/ + 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 lazy mode. "); + goto codec_revert; + } else if (strncmp("Lazy", in, 4) == 0) { + fprintf(stderr, "Server switched to lazy mode\n"); + lazymode = 1; + return; + } + } + /*XXX END adjust indent 1 tab back*/ + + fprintf(stderr, "Retrying lazy mode switch...\n"); + } + if (!running) + return; + + fprintf(stderr, "No reply from server on lazy switch. "); + +codec_revert: + fprintf(stderr, "Falling back to legacy mode\n"); + lazymode = 0; + selecttimeout = 1; +} + +static void +handshake_lazyoff(int dns_fd) +/* Used in the middle of data transfer, timing is different and no error msgs */ +{ + char in[4096]; + int i; + int read; + + for (i=0; running && i<5; i++) { + + send_lazy_switch(dns_fd, userid); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'o', 'O', 1); + + /*XXX START adjust indent 2 tabs back*/ + if (read == 9 && strncmp("Immediate", in, 9) == 0) { + warnx("Server switched back to legacy mode.\n"); + lazymode = 0; + selecttimeout = 1; + return; + } + /*XXX END adjust indent 2 tabs back*/ + } + if (!running) + return; + + warnx("No reply from server on legacy mode switch.\n"); +} + +static int +fragsize_check(char *in, int read, int proposed_fragsize, int *max_fragsize) +/* Returns: 0: keep checking, 1: break loop (either okay or definitely wrong) */ +{ + int acked_fragsize = ((in[0] & 0xff) << 8) | (in[1] & 0xff); + int okay; + int i; + unsigned int v; + + if (read >= 5 && strncmp("BADIP", in, 5) == 0) { + fprintf(stderr, "got BADIP (Try iodined -c)..\n"); + fflush(stderr); + return 0; /* maybe temporary error */ + } + + if (acked_fragsize != proposed_fragsize) { + /* + * got ack for wrong fragsize, maybe late response for + * earlier query, or ack corrupted + */ + return 0; + } + + if (read != proposed_fragsize) { + /* + * correctly acked fragsize but read too little (or too + * much): this fragsize is definitely not reliable + */ + return 1; + } + + /* here: read == proposed_fragsize == acked_fragsize */ + + /* test: */ + /* in[123] = 123; */ + + if ((in[2] & 0xff) != 107) { + fprintf(stderr, "\n"); + warnx("corruption at byte 2, this won't work. Try -O Base32, or other -T options."); + *max_fragsize = -1; + return 1; + } + + /* Check for corruption */ + okay = 1; + v = in[3] & 0xff; + + /*XXX START adjust indent 1 tab back*/ + for (i = 3; i < read; i++, v = (v + 107) & 0xff) + if ((in[i] & 0xff) != v) { + okay = 0; + break; + } + + if (okay) { + fprintf(stderr, "%d ok.. ", acked_fragsize); + fflush(stderr); + *max_fragsize = acked_fragsize; + return 1; + } else { + if (downenc != ' ' && downenc != 'T') { + fprintf(stderr, "%d corrupted at %d.. (Try -O Base32)\n", acked_fragsize, i); + } else { + fprintf(stderr, "%d corrupted at %d.. ", acked_fragsize, i); + } + fflush(stderr); + return 1; + } + /*XXX END adjust indent 1 tab back*/ + + /* notreached */ + return 1; +} + + +static int +handshake_autoprobe_fragsize(int dns_fd) +{ + char in[4096]; + int i; + int read; + int proposed_fragsize = 768; + int range = 768; + int max_fragsize; + + max_fragsize = 0; + fprintf(stderr, "Autoprobing max downstream fragment size... (skip with -m fragsize)\n"); + while (running && range > 0 && (range >= 8 || max_fragsize < 300)) { + /* stop the slow probing early when we have enough bytes anyway */ + for (i=0; running && i<3 ;i++) { + + send_fragsize_probe(dns_fd, proposed_fragsize); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'r', 'R', 1); + + /*XXX START adjust indent 1 tab back*/ + if (read > 0) { + /* We got a reply */ + if (fragsize_check(in, read, proposed_fragsize, &max_fragsize) == 1) + break; + } + /*XXX END adjust indent 1 tab back*/ + + fprintf(stderr, "."); + fflush(stderr); + } + if (max_fragsize < 0) + break; + + 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 setting manually with -m)"); + return 0; + } + if (max_fragsize <= 2) { + /* Tried all the way down to 2 and found no good size. + But we _did_ do all handshake before this, so there must + be some workable connection. */ + fprintf(stderr, "\n"); + warnx("found no accepted fragment size."); + warnx("try setting -M to 200 or lower, or try other -T or -O options."); + return 0; + } + /* data header adds 2 bytes */ + fprintf(stderr, "will use %d-2=%d\n", max_fragsize, max_fragsize - 2); + + /* need 1200 / 16frags = 75 bytes fragsize */ + if (max_fragsize < 82) { + fprintf(stderr, "Note: this probably won't work well.\n"); + fprintf(stderr, "Try setting -M to 200 or lower, or try other DNS types (-T option).\n"); + } else if (max_fragsize < 202 && + (do_qtype == T_NULL || do_qtype == T_TXT || + do_qtype == T_SRV || do_qtype == T_MX)) { + fprintf(stderr, "Note: this isn't very much.\n"); + fprintf(stderr, "Try setting -M to 200 or lower, or try other DNS types (-T option).\n"); + } + + return max_fragsize - 2; +} + +static void +handshake_set_fragsize(int dns_fd, int fragsize) +{ + char in[4096]; + int i; + int read; + + fprintf(stderr, "Setting downstream fragment size to max %d...\n", fragsize); + for (i=0; running && i<5 ;i++) { + + send_set_downstream_fragsize(dns_fd, fragsize); + + read = handshake_waitdns(dns_fd, in, sizeof(in), 'n', 'N', i+1); + + /*XXX START adjust indent 1 tab back*/ + 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; + } + /*XXX END adjust indent 1 tab back*/ + + fprintf(stderr, "Retrying set fragsize...\n"); + } + if (!running) + return; + + 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 upcodec; + int r; + + dnsc_use_edns0 = 0; + + /* qtype message printed in handshake function */ + if (do_qtype == T_UNSET) { + r = handshake_qtype_autodetect(dns_fd); + if (r) { + return r; + } + } + + fprintf(stderr, "Using DNS type %s queries\n", get_qtype()); + + 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; + selecttimeout = 20; + } else { + if (raw_mode == 0) { + fprintf(stderr, "Skipping raw mode\n"); + } + + dnsc_use_edns0 = 1; + if (handshake_edns0_check(dns_fd) && running) { + fprintf(stderr, "Using EDNS0 extension\n"); + } else if (!running) { + return -1; + } else { + fprintf(stderr, "DNS relay does not support EDNS0 extension\n"); + dnsc_use_edns0 = 0; + } + + upcodec = handshake_upenc_autodetect(dns_fd); + if (!running) + return -1; + + if (upcodec == 1) { + handshake_switch_codec(dns_fd, 6); + } else if (upcodec == 2) { + handshake_switch_codec(dns_fd, 26); + } else if (upcodec == 3) { + handshake_switch_codec(dns_fd, 7); + } + if (!running) + return -1; + + if (downenc == ' ') { + downenc = handshake_downenc_autodetect(dns_fd); + } + if (!running) + return -1; + + if (downenc != ' ') { + handshake_switch_downenc(dns_fd); + } + if (!running) + return -1; + + if (lazymode) { + handshake_try_lazy(dns_fd); + } + if (!running) + return -1; + + if (autodetect_frag_size) { + fragsize = handshake_autoprobe_fragsize(dns_fd); + if (!fragsize) { + return 1; + } + } + + handshake_set_fragsize(dns_fd, fragsize); + if (!running) + return -1; + } + + return 0; +} + -- cgit v1.2.1