From 5233c2ab1e33704f526cf0f3caf11d4e5b87feb2 Mon Sep 17 00:00:00 2001 From: frekky Date: Fri, 22 Jan 2016 21:57:33 +0800 Subject: [PATCH] Cleaned up client send_packet functions, protocol changes --- src/client.c | 305 +++++++++++++++++++++++---------------------------- 1 file changed, 135 insertions(+), 170 deletions(-) diff --git a/src/client.c b/src/client.c index bcad2c4..c46eb27 100644 --- a/src/client.c +++ b/src/client.c @@ -426,13 +426,22 @@ send_raw_data(uint8_t *data, size_t datalen) static int send_packet(char cmd, const uint8_t *data, const size_t datalen) /* Base32 encodes data and sends as single DNS query + * cmd becomes first byte of query, followed by hex userid, encoded + * data and 3 bytes base32 encoded CMC * Returns ID of sent query */ { - uint8_t buf[4096]; + uint8_t buf[512], data_with_cmc[datalen + 2]; + + if (data) + memcpy(data_with_cmc, data, datalen); + *(uint16_t *) (data_with_cmc + datalen) = this.rand_seed; + this.rand_seed++; buf[0] = cmd; + buf[1] = this.userid_char; - build_hostname(buf, sizeof(buf), data, datalen, this.topdomain, b32, this.hostname_maxlen, 1); + build_hostname(buf, sizeof(buf), data_with_cmc, datalen + 2, + this.topdomain, b32, this.hostname_maxlen, 2); return send_query(buf); } @@ -442,27 +451,26 @@ send_ping(int ping_response, int ack, int set_timeout) { this.num_pings++; if (this.conn == CONN_DNS_NULL) { - uint8_t data[13]; + uint8_t data[12]; int id; /* Build ping header (see doc/proto_xxxxxxxx.txt) */ - data[0] = this.userid; - data[1] = ack & 0xFF; + data[0] = ack & 0xFF; if (this.outbuf && this.inbuf) { - data[2] = this.outbuf->windowsize & 0xff; /* Upstream window size */ - data[3] = this.inbuf->windowsize & 0xff; /* Downstream window size */ - data[4] = this.outbuf->start_seq_id & 0xff; /* Upstream window start */ - data[5] = this.inbuf->start_seq_id & 0xff; /* Downstream window start */ + data[1] = this.outbuf->windowsize & 0xff; /* Upstream window size */ + data[2] = this.inbuf->windowsize & 0xff; /* Downstream window size */ + data[3] = this.outbuf->start_seq_id & 0xff; /* Upstream window start */ + data[4] = this.inbuf->start_seq_id & 0xff; /* Downstream window start */ } - *(uint16_t *) (data + 6) = htons(this.server_timeout_ms); - *(uint16_t *) (data + 8) = htons(this.downstream_timeout_ms); + *(uint16_t *) (data + 5) = htons(this.server_timeout_ms); + *(uint16_t *) (data + 7) = htons(this.downstream_timeout_ms); /* update server frag/lazy timeout, ack flag, respond with ping flag */ - data[10] = ((set_timeout & 1) << 4) | ((set_timeout & 1) << 3) | ((ack < 0 ? 0 : 1) << 2) | (ping_response & 1); - data[11] = (this.rand_seed >> 8) & 0xff; - data[12] = (this.rand_seed >> 0) & 0xff; + data[9] = ((set_timeout & 1) << 4) | ((set_timeout & 1) << 3) | ((ack < 0 ? 0 : 1) << 2) | (ping_response & 1); + data[10] = (this.rand_seed >> 8) & 0xff; + data[11] = (this.rand_seed >> 0) & 0xff; this.rand_seed += 1; DEBUG(3, " SEND PING: respond %d, ack %d, %s(server %ld ms, downfrag %ld ms), flags %02X", @@ -1309,116 +1317,17 @@ client_tunnel() return rv; } -static void -send_login(char *login, int len) -{ - uint8_t data[19]; - - memset(data, 0, sizeof(data)); - data[0] = this.userid; - memcpy(&data[1], login, MIN(len, 16)); - - data[17] = (this.rand_seed >> 8) & 0xff; - data[18] = (this.rand_seed >> 0) & 0xff; - - this.rand_seed++; - - send_packet('l', data, sizeof(data)); -} - -static void -send_fragsize_probe(uint16_t fragsize) -{ - uint8_t probedata[256]; - uint8_t buf[MAX_FRAGSIZE]; - uint8_t hdr[3]; - size_t hdr_len_enc = 6; - - buf[0] = 'r'; /* Probe downstream fragsize packet */ - - hdr[0] = this.userid; - *(uint16_t *) (hdr + 1) = htons(fragsize); - - b32->encode(buf + 1, &hdr_len_enc, hdr, 3); - /* build a large query domain which is random and maximum size, - * will also take up maximum space in the return packet */ - memset(probedata, MAX(1, this.rand_seed & 0xff), sizeof(probedata)); - probedata[1] = MAX(1, (this.rand_seed >> 8) & 0xff); - this.rand_seed++; - - /* Note: must either be same, or larger, than send_chunk() */ - build_hostname(buf, sizeof(buf), probedata, sizeof(probedata), this.topdomain, - this.dataenc, this.hostname_maxlen, 6); - - send_query(buf); -} - -static void -send_set_downstream_fragsize(uint16_t fragsize) -{ - uint8_t data[5]; - - data[0] = this.userid; - *(uint16_t *) (data + 1) = htons(fragsize); - data[3] = (this.rand_seed >> 8) & 0xff; - data[4] = (this.rand_seed >> 0) & 0xff; - - this.rand_seed++; - - send_packet('n', data, sizeof(data)); -} - -static void -send_version(uint32_t version) -{ - uint8_t data[6]; - - version = htonl(version); - *(uint32_t *) data = version; - - data[4] = (this.rand_seed >> 8) & 0xff; - data[5] = (this.rand_seed >> 0) & 0xff; - - this.rand_seed++; - - send_packet('v', data, sizeof(data)); -} - -static void -send_ip_request() -{ - uint8_t buf[512] = "i____."; - buf[1] = b32_5to8(this.userid); - - buf[2] = b32_5to8((this.rand_seed >> 10) & 0x1f); - buf[3] = b32_5to8((this.rand_seed >> 5) & 0x1f); - buf[4] = b32_5to8((this.rand_seed ) & 0x1f); - this.rand_seed++; - - strncat((char *)buf, this.topdomain, 512 - strlen((char *)buf)); - send_query(buf); -} - -static void -send_raw_udp_login(int seed) -{ - char buf[16]; - login_calculate(buf, 16, this.password, seed + 1); - - send_raw((uint8_t *) buf, sizeof(buf), RAW_HDR_CMD_LOGIN); -} - static void send_upenctest(char *s) /* NOTE: String may be at most 63-4=59 chars to fit in 1 dns chunk. */ { - char buf[512] = "z___"; + char buf[512] = "z___."; + size_t buf_space = 3; - buf[1] = b32_5to8((this.rand_seed >> 10) & 0x1f); - buf[2] = b32_5to8((this.rand_seed >> 5) & 0x1f); - buf[3] = b32_5to8((this.rand_seed ) & 0x1f); + b32->encode((uint8_t *)buf + 1, &buf_space,(uint8_t *)&this.rand_seed, sizeof(this.rand_seed)); this.rand_seed++; + /* Append test string without changing it */ strncat(buf, s, 512 - strlen(buf)); strncat(buf, ".", 512 - strlen(buf)); strncat(buf, this.topdomain, 512 - strlen(buf)); @@ -1426,59 +1335,110 @@ send_upenctest(char *s) } static void -send_downenctest(char downenc, int variant, char *s, int slen) -/* Note: content/handling of s is not defined yet. */ +send_downenctest(char downenc, int variant) { - char buf[512] = "y_____."; + uint8_t buf[512] = "y_____.", hdr[3]; buf[1] = tolower(downenc); - buf[2] = b32_5to8(variant); - buf[3] = b32_5to8((this.rand_seed >> 10) & 0x1f); - buf[4] = b32_5to8((this.rand_seed >> 5) & 0x1f); - buf[5] = b32_5to8((this.rand_seed ) & 0x1f); + hdr[0] = variant; + *(uint16_t *) (hdr + 1) = this.rand_seed; this.rand_seed++; - strncat(buf, this.topdomain, 512 - strlen(buf)); - send_query((uint8_t *)buf); + build_hostname(buf, sizeof(buf), hdr, sizeof(hdr), + this.topdomain, b32, this.hostname_maxlen, 2); + + send_query(buf); } static void -send_codec_switch(int bits) +send_version(uint32_t version) { - char buf[512] = "s_____."; - buf[1] = b32_5to8(this.userid); - buf[2] = b32_5to8(bits); + uint8_t data[4], buf[512]; - buf[3] = b32_5to8((this.rand_seed >> 10) & 0x1f); - buf[4] = b32_5to8((this.rand_seed >> 5) & 0x1f); - buf[5] = b32_5to8((this.rand_seed ) & 0x1f); - this.rand_seed++; + *(uint32_t *) data = htonl(version); - strncat(buf, this.topdomain, 512 - strlen(buf)); - send_query((uint8_t *)buf); + buf[0] = 'v'; + + build_hostname(buf, sizeof(buf), data, sizeof(data), + this.topdomain, b32, this.hostname_maxlen, 1); + + send_query(buf); } static void -send_server_options(int lazy, int compression, char denc, char *options) -/* Options must be length >=4 */ +send_login(char *login, int len) { - char buf[512] = "oU3___CMC."; - buf[1] = b32_5to8(this.userid); + send_packet('l', (uint8_t *) login, len); +} - options[0] = tolower(denc); - options[1] = lazy ? 'l' : 'i'; - options[2] = compression ? 'c' : 'd'; - options[3] = 0; - strncpy(buf + 3, options, 3); +static void +send_fragsize_probe(uint16_t fragsize) +{ + uint8_t data[256]; - buf[6] = b32_5to8((this.rand_seed >> 10) & 0x1f); - buf[7] = b32_5to8((this.rand_seed >> 5) & 0x1f); - buf[8] = b32_5to8((this.rand_seed) & 0x1f); + /* Probe downstream fragsize packet */ + + /* build a large query domain which is random and maximum size, + * will also take up maximum space in the return packet */ + memset(data, MAX(1, this.rand_seed & 0xff), sizeof(data)); + + *(uint16_t *) (data) = htons(fragsize); this.rand_seed++; - strncat(buf, this.topdomain, 512 - strlen(buf)); - send_query((uint8_t *)buf); + send_packet('r', data, sizeof(data)); +} + +static void +send_set_downstream_fragsize(uint16_t fragsize) +{ + uint8_t data[2]; + *(uint16_t *) data = htons(fragsize); + + send_packet('n', data, sizeof(data)); +} + +static void +send_ip_request() +{ + send_packet('i', NULL, 0); +} + +static void +send_raw_udp_login(int seed) +{ + char buf[16]; + login_calculate(buf, sizeof(buf), this.password, seed + 1); + + send_raw((uint8_t *) buf, sizeof(buf), RAW_HDR_CMD_LOGIN); +} + +static void +send_codec_switch(uint8_t bits) +{ + send_packet('s', &bits, 1); +} + +static void +send_server_options(int lazy, int compression, char denc) +{ + uint8_t optflags = 0; + + if (denc == 'T') /* Base32 */ + optflags |= 1 << 6; + else if (denc == 'S') /* Base64 */ + optflags |= 1 << 5; + else if (denc == 'U') /* Base64u */ + optflags |= 1 << 4; + else if (denc == 'V') /* Base128 */ + optflags |= 1 << 3; + else if (denc == 'R') /* Raw */ + optflags |= 1 << 2; + + optflags |= (compression & 1) << 1; + optflags |= lazy & 1; + + send_packet('o', &optflags, 1); } static int @@ -1498,25 +1458,27 @@ handshake_version(int *seed) read = handshake_waitdns(in, sizeof(in), 'V', i+1); if (read >= 9) { - payload = (((in[4] & 0xff) << 24) | - ((in[5] & 0xff) << 16) | - ((in[6] & 0xff) << 8) | - ((in[7] & 0xff))); + payload = ntohl(*(uint32_t *) (in + 4)); if (strncmp("VACK", (char *)in, 4) == 0) { + /* Payload is login challenge */ *seed = payload; this.userid = in[8]; this.userid_char = hex[this.userid & 15]; this.userid_char2 = hex2[this.userid & 15]; + DEBUG(2, "Login challenge: 0x%08x", *seed); + fprintf(stderr, "Version ok, both using protocol v 0x%08x. You are user #%d\n", PROTOCOL_VERSION, this.userid); return 0; } else if (strncmp("VNAK", (char *)in, 4) == 0) { + /* Payload is server version */ warnx("You use protocol v 0x%08x, server uses v 0x%08x. Giving up", PROTOCOL_VERSION, payload); return 1; } else if (strncmp("VFUL", (char *)in, 4) == 0) { + /* Payload is max number of users on server */ warnx("Server full, all %d slots are taken. Try again later", payload); return 1; } @@ -1547,11 +1509,12 @@ handshake_login(int seed) send_login(login, 16); read = handshake_waitdns(in, sizeof(in), 'L', i+1); + in[MIN(read, sizeof(in))] = 0; /* Null terminate */ if (read > 0) { int netmask; if (strncmp("LNAK", in, 4) == 0) { - fprintf(stderr, "Bad this.password\n"); + fprintf(stderr, "Bad password\n"); return 1; } else if (sscanf(in, "%64[^-]-%64[^-]-%d-%d", server, client, &mtu, &netmask) == 4) { @@ -1567,7 +1530,7 @@ handshake_login(int seed) errx(4, "Failed to set IP and MTU"); } } else { - fprintf(stderr, "Received bad handshake\n"); + fprintf(stderr, "Received bad handshake: %.*s\n", read, in); } } @@ -1682,9 +1645,7 @@ handshake_upenctest(char *s) char in[4096]; unsigned char *uin = (unsigned char *) in; unsigned char *us = (unsigned char *) s; - int i; - int read; - int slen; + int i, read, slen; slen = strlen(s); for (i=0; this.running && i<3 ;i++) { @@ -1850,7 +1811,7 @@ handshake_downenctest(char trycodec) for (i=0; this.running && i<3 ;i++) { - send_downenctest(trycodec, 1, NULL, 0); + send_downenctest(trycodec, 1); read = handshake_waitdns(in, sizeof(in), 'Y', i+1); @@ -1950,7 +1911,7 @@ handshake_qtypetest(int timeout) byte values can be returned, which is needed for NULL/PRIVATE to work. */ - send_downenctest(trycodec, 1, NULL, 0); + send_downenctest(trycodec, 1); read = handshake_waitdns(in, sizeof(in), 'Y', timeout); @@ -2073,7 +2034,7 @@ handshake_edns0_check() for (i=0; this.running && i<3 ;i++) { - send_downenctest(trycodec, 1, NULL, 0); + send_downenctest(trycodec, 1); read = handshake_waitdns(in, sizeof(in), 'Y', i+1); @@ -2162,10 +2123,9 @@ codec_revert: void handshake_switch_options(int lazy, int compression, char denc) { - char in[4096]; + char in[100]; int read; char *dname, *comp_status, *lazy_status; - char opts[4]; comp_status = compression ? "enabled" : "disabled"; @@ -2185,11 +2145,13 @@ handshake_switch_options(int lazy, int compression, char denc) lazy_status, dname, comp_status); for (int i = 0; this.running && i < 5; i++) { - send_server_options(lazy, compression, denc, opts); + send_server_options(lazy, compression, denc); read = handshake_waitdns(in, sizeof(in) - 1, 'O', i + 1); if (read > 0) { + in[read] = 0; /* zero terminate */ + if (strncmp("BADLEN", in, 6) == 0) { fprintf(stderr, "Server got bad message length.\n"); goto opt_revert; @@ -2199,12 +2161,15 @@ handshake_switch_options(int lazy, int compression, char denc) } else if (strncmp("BADCODEC", in, 8) == 0) { fprintf(stderr, "Server rejected the selected options.\n"); goto opt_revert; + } else if (strcasecmp(dname, in) == 0) { + fprintf(stderr, "Switched server options, using downsteam codec %s.\n", in); + this.lazymode = lazy; + this.compression_down = compression; + this.downenc = denc; + return; + } else { + fprintf(stderr, "Got invalid response. "); } - fprintf(stderr, "Switched server options successfully. (%s)\n", opts); - this.lazymode = lazy; - this.compression_down = compression; - this.downenc = denc; - return; } fprintf(stderr, "Retrying options switch...\n");