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add downstream data header and basic parsing in client, for #7
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parent
7dd38fec17
commit
55d9ddb8dd
2 changed files with 32 additions and 5 deletions
19
src/iodine.c
19
src/iodine.c
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@ -59,6 +59,8 @@ static struct sockaddr_in nameserv;
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static char *topdomain;
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static uint16_t rand_seed;
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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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@ -171,6 +173,12 @@ read_dns(int fd, char *buf, int buflen)
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rv = dns_decode(buf, buflen, &q, QR_ANSWER, data, r);
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/* decode the data header, update seqno and frag before next request */
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if (rv > 2) {
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downstream_seqno = (buf[1] >> 5) & 7;
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downstream_fragment = (buf[1] >> 1) & 15;
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}
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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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@ -230,7 +238,9 @@ tunnel_dns(int tun_fd, int dns_fd)
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outlen = sizeof(out);
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inlen = read;
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if (uncompress((uint8_t*)out, &outlen, (uint8_t*)in, inlen) != Z_OK) {
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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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return -1;
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}
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@ -309,10 +319,10 @@ send_chunk(int fd)
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code = ((packet.seqno & 7) << 2) | ((packet.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) | (0);
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code = ((packet.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 = (0 << 1) | (packet.sentlen == avail);
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code = ((downstream_fragment & 15) << 1) | (packet.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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@ -837,6 +847,9 @@ main(int argc, char **argv)
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}
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}
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downstream_seqno = 0;
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downstream_fragment = 0;
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tunnel(tun_fd, dns_fd);
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cleanup2:
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@ -160,12 +160,26 @@ send_version_response(int fd, version_ack_t ack, uint32_t payload, int userid, s
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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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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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/* 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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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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users[userid].outpacket.seqno & 7, users[userid].outpacket.fragment & 15,
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1, users[userid].outpacket.len, users[userid].outpacket.len, userid);
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1, users[userid].outpacket.len, datalen, userid);
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}
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write_dns(dns_fd, &users[userid].q, users[userid].outpacket.data, users[userid].outpacket.len);
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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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}
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