mirror of
https://github.com/yarrick/iodine.git
synced 2024-11-27 12:05:15 +00:00
Downstream fragmentation now working. Currently fragment size is hardcoded to 1200. More tweaking left, as well as fragsize auto detection. (#7)
This commit is contained in:
Erik Ekman
parent
d5f0dac459
commit
20cfb002c3
@ -269,7 +269,7 @@ dns_decode(char *buf, size_t buflen, struct query *q, qr_t qr, char *packet, siz
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rv = MIN(rlen, sizeof(rdata));
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rv = readdata(packet, &data, rdata, rv);
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if(type == T_NULL && rv > 2 && buf) {
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if(type == T_NULL && rv >= 2 && buf) {
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rv = MIN(rv, buflen);
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memcpy(buf, rdata, rv);
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}
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92
src/iodine.c
92
src/iodine.c
@ -63,7 +63,8 @@ static int downstream_seqno;
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static int downstream_fragment;
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/* Current IP packet */
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static struct packet packet;
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static struct packet outpkt;
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static struct packet inpkt;
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/* My userid at the server */
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static char userid;
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@ -151,7 +152,7 @@ build_hostname(char *buf, size_t buflen,
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static int
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is_sending()
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{
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return (packet.len != 0);
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return (outpkt.len != 0);
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}
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static int
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@ -181,12 +182,12 @@ read_dns(int fd, char *buf, int buflen)
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if (is_sending() && chunkid == q.id) {
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/* Got ACK on sent packet */
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packet.offset += packet.sentlen;
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if (packet.offset == packet.len) {
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outpkt.offset += outpkt.sentlen;
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if (outpkt.offset == outpkt.len) {
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/* Packet completed */
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packet.offset = 0;
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packet.len = 0;
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packet.sentlen = 0;
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outpkt.offset = 0;
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outpkt.len = 0;
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outpkt.sentlen = 0;
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} else {
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/* More to send */
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send_chunk(fd);
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@ -212,12 +213,12 @@ tunnel_tun(int tun_fd, int dns_fd)
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inlen = read;
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compress2((uint8_t*)out, &outlen, (uint8_t*)in, inlen, 9);
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memcpy(packet.data, out, MIN(outlen, sizeof(packet.data)));
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packet.sentlen = 0;
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packet.offset = 0;
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packet.len = outlen;
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packet.seqno++;
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packet.fragment = 0;
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memcpy(outpkt.data, out, MIN(outlen, sizeof(outpkt.data)));
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outpkt.sentlen = 0;
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outpkt.offset = 0;
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outpkt.len = outlen;
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outpkt.seqno++;
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outpkt.fragment = 0;
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send_chunk(dns_fd);
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@ -227,24 +228,40 @@ tunnel_tun(int tun_fd, int dns_fd)
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static int
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tunnel_dns(int tun_fd, int dns_fd)
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{
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unsigned long outlen;
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unsigned long inlen;
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char out[64*1024];
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char in[64*1024];
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unsigned long datalen;
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char buf[64*1024];
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size_t read;
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if ((read = read_dns(dns_fd, in, sizeof(in))) <= 2)
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if ((read = read_dns(dns_fd, buf, sizeof(buf))) <= 2)
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return -1;
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outlen = sizeof(out);
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inlen = read;
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/* Skip 2 byte data header and uncompress */
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if (uncompress((uint8_t*)out, &outlen, (uint8_t*) &in[2], inlen - 2) != Z_OK) {
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if (downstream_seqno != inpkt.seqno) {
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/* New packet */
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inpkt.seqno = downstream_seqno;
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inpkt.fragment = downstream_fragment;
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inpkt.len = 0;
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} else if (downstream_fragment <= inpkt.fragment) {
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/* Duplicate fragment */
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return -1;
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}
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inpkt.fragment = downstream_fragment;
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write_tun(tun_fd, out, outlen);
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datalen = MIN(read - 2, sizeof(inpkt.data) - inpkt.len);
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/* Skip 2 byte data header and append to packet */
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memcpy(&inpkt.data[inpkt.len], &buf[2], datalen);
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inpkt.len += datalen;
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if (buf[1] & 1) { /* If last fragment flag is set */
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/* Uncompress packet and send to tun */
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datalen = sizeof(buf);
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if (uncompress((uint8_t*)buf, &datalen, (uint8_t*) inpkt.data, inpkt.len) == Z_OK) {
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write_tun(tun_fd, buf, datalen);
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}
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inpkt.len = 0;
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}
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/* If we have nothing to send, send a ping to get more data */
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if (!is_sending())
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send_ping(dns_fd);
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@ -306,26 +323,26 @@ send_chunk(int fd)
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int code;
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char *p;
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p = packet.data;
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p += packet.offset;
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avail = packet.len - packet.offset;
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p = outpkt.data;
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p += outpkt.offset;
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avail = outpkt.len - outpkt.offset;
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packet.sentlen = build_hostname(buf + 4, sizeof(buf) - 4, p, avail, topdomain, dataenc);
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outpkt.sentlen = build_hostname(buf + 4, sizeof(buf) - 4, p, avail, topdomain, dataenc);
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/* Build upstream data header (see doc/proto_xxxxxxxx.txt) */
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buf[0] = hex[userid & 15]; /* First byte is 4 bits userid */
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code = ((packet.seqno & 7) << 2) | ((packet.fragment & 15) >> 2);
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code = ((outpkt.seqno & 7) << 2) | ((outpkt.fragment & 15) >> 2);
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buf[1] = b32_5to8(code); /* Second byte is 3 bits seqno, 2 upper bits fragment count */
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code = ((packet.fragment & 3) << 3) | (downstream_seqno & 7);
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code = ((outpkt.fragment & 3) << 3) | (downstream_seqno & 7);
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buf[2] = b32_5to8(code); /* Third byte is 2 bits lower fragment count, 3 bits downstream packet seqno */
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code = ((downstream_fragment & 15) << 1) | (packet.sentlen == avail);
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code = ((downstream_fragment & 15) << 1) | (outpkt.sentlen == avail);
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buf[3] = b32_5to8(code); /* Fourth byte is 4 bits downstream fragment count, 1 bit compression flag */
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packet.fragment++;
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outpkt.fragment++;
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send_query(fd, buf);
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}
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@ -352,13 +369,13 @@ send_ping(int fd)
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char data[4];
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if (is_sending()) {
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packet.sentlen = 0;
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packet.offset = 0;
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packet.len = 0;
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outpkt.sentlen = 0;
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outpkt.offset = 0;
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outpkt.len = 0;
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}
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data[0] = userid;
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data[1] = 0;
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data[1] = ((downstream_seqno & 7) << 4) | (downstream_fragment & 15);
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data[2] = (rand_seed >> 8) & 0xff;
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data[3] = (rand_seed >> 0) & 0xff;
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@ -722,7 +739,8 @@ main(int argc, char **argv)
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device = NULL;
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chunkid = 0;
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packet.seqno = 0;
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outpkt.seqno = 0;
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inpkt.len = 0;
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b32 = get_base32_encoder();
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dataenc = get_base32_encoder();
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@ -118,7 +118,7 @@ tunnel_tun(int tun_fd, int dns_fd)
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users[userid].outpacket.len = outlen;
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users[userid].outpacket.offset = 0;
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users[userid].outpacket.sentlen = 0;
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users[userid].outpacket.seqno++;
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users[userid].outpacket.seqno = (++users[userid].outpacket.seqno & 7);
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users[userid].outpacket.fragment = 0;
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return outlen;
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} else {
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@ -162,47 +162,92 @@ static void
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send_chunk(int dns_fd, int userid) {
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char pkt[4096];
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int datalen;
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int last;
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datalen = MIN(sizeof(pkt) - 2, users[userid].outpacket.len);
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memcpy(&pkt[2], users[userid].outpacket.data, datalen);
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/* TODO change this 1200b value to dynamic */
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datalen = MIN(1200, users[userid].outpacket.len - users[userid].outpacket.offset);
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if (datalen && users[userid].outpacket.sentlen > 0 &&
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(
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users[userid].outpacket.seqno != users[userid].out_acked_seqno ||
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users[userid].outpacket.fragment != users[userid].out_acked_fragment
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)
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) {
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/* Still waiting on latest ack, send nothing */
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datalen = 0;
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last = 0;
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/* TODO : count down and discard packet if no acks arrive within X queries */
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} else {
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memcpy(&pkt[2], &users[userid].outpacket.data[users[userid].outpacket.offset], datalen);
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users[userid].outpacket.sentlen = datalen;
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last = (users[userid].outpacket.len == users[userid].outpacket.offset + users[userid].outpacket.sentlen);
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/* Increase fragment# when sending data with offset */
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if (users[userid].outpacket.offset && datalen)
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users[userid].outpacket.fragment++;
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}
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/* Build downstream data header (see doc/proto_xxxxxxxx.txt) */
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/* First byte is 1 bit compression flag, 3 bits upstream seqno, 4 bits upstream fragment */
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pkt[0] = (1<<7) | ((users[userid].inpacket.seqno & 7) << 4) | (users[userid].inpacket.fragment & 15);
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/* Second byte is 3 bits downstream seqno, 4 bits downstream fragment, 1 bit last flag */
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pkt[1] = ((users[userid].outpacket.seqno & 7) << 5) | ((users[userid].outpacket.fragment & 15) << 1) | 1;
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pkt[1] = ((users[userid].outpacket.seqno & 7) << 5) |
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((users[userid].outpacket.fragment & 15) << 1) | (last & 1);
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if (debug >= 1) {
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printf("OUT pkt seq# %d, frag %d (last=%d), fragsize %d, total %d, to user %d\n",
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printf("OUT pkt seq# %d, frag %d (last=%d), offset %d, fragsize %d, total %d, to user %d\n",
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users[userid].outpacket.seqno & 7, users[userid].outpacket.fragment & 15,
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1, users[userid].outpacket.len, datalen, userid);
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last, users[userid].outpacket.offset, datalen, users[userid].outpacket.len, userid);
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}
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write_dns(dns_fd, &users[userid].q, pkt, datalen + 2);
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users[userid].outpacket.len = 0;
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users[userid].q.id = 0;
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if (users[userid].outpacket.len > 0 &&
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users[userid].outpacket.len == users[userid].outpacket.sentlen) {
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/* Whole packet was sent in one chunk, dont wait for ack */
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users[userid].outpacket.len = 0;
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users[userid].outpacket.offset = 0;
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users[userid].outpacket.sentlen = 0;
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}
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}
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static void
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update_downstream_seqno(int dns_fd, int userid, int down_seq, int down_frag)
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{
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/* update outgoing seqno/frag */
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if (down_seq != users[userid].out_acked_seqno) {
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/* First ack on new outgoing packet */
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/* If we just read a new packet from tun we have not sent a fragment of, just send it */
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if (users[userid].outpacket.len > 0 && users[userid].outpacket.sentlen == 0) {
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send_chunk(dns_fd, userid);
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return;
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}
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/* otherwise, check if we received ack on a fragment and can send next */
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if (users[userid].outpacket.len > 0 &&
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users[userid].outpacket.seqno == down_seq && users[userid].outpacket.fragment == down_frag) {
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if (down_seq != users[userid].out_acked_seqno || down_frag != users[userid].out_acked_fragment) {
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/* Received ACK on downstream fragment */
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users[userid].outpacket.offset += users[userid].outpacket.sentlen;
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users[userid].outpacket.sentlen = 0;
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/* Is packet done? */
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if (users[userid].outpacket.offset == users[userid].outpacket.len) {
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users[userid].outpacket.len = 0;
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users[userid].outpacket.offset = 0;
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users[userid].outpacket.sentlen = 0;
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}
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users[userid].out_acked_seqno = down_seq;
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users[userid].out_acked_fragment = down_frag;
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} else {
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if (down_frag > users[userid].out_acked_fragment) {
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/* Ack on later fragment */
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users[userid].out_acked_fragment = down_frag;
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}
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}
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/* Send reply if waiting */
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if (users[userid].outpacket.len > 0) {
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send_chunk(dns_fd, userid);
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}
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}
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}
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}
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static void
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@ -345,6 +390,15 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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return; /* illegal id */
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}
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if (debug >= 1) {
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printf("PING pkt from user %d\n", userid);
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}
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if (users[userid].q.id != 0) {
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/* Send reply on earlier query before overwriting */
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send_chunk(dns_fd, userid);
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}
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dn_seq = unpacked[1] >> 4;
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dn_frag = unpacked[1] & 15;
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memcpy(&(users[userid].q), q, sizeof(struct query));
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@ -379,6 +433,11 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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int dn_frag = b32_8to5(in[3]) >> 1;
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int lastfrag = b32_8to5(in[3]) & 1;
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if (users[userid].q.id != 0) {
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/* Send reply on earlier query before overwriting */
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send_chunk(dns_fd, userid);
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}
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/* Update query and time info for user */
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users[userid].last_pkt = time(NULL);
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memcpy(&(users[userid].q), q, sizeof(struct query));
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