mirror of
https://github.com/yarrick/iodine.git
synced 2024-12-25 00:57:46 +00:00
update server code #75
This commit is contained in:
J. A. Bezemer
Erik Ekman
parent
55cfed9956
commit
40167437d3
199
src/iodined.c
199
src/iodined.c
@ -68,6 +68,7 @@ static int running = 1;
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static char *topdomain;
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static char password[33];
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static struct encoder *b32;
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static struct encoder *b64;
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static int created_users;
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static int check_ip;
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@ -85,7 +86,7 @@ static char *__progname;
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#endif
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static int read_dns(int, int, struct query *);
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static void write_dns(int, struct query *, char *, int);
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static void write_dns(int, struct query *, char *, int, char);
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static void handle_full_packet(int, int);
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static void
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@ -119,7 +120,7 @@ check_user_and_ip(int userid, struct query *q)
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if (userid < 0 || userid >= created_users ) {
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return 1;
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}
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if (!users[userid].active) {
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if (!users[userid].active || users[userid].disabled) {
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return 1;
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}
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if (users[userid].last_pkt + 60 < time(NULL)) {
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@ -225,7 +226,7 @@ send_version_response(int fd, version_ack_t ack, uint32_t payload, int userid, s
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out[7] = ((payload) & 0xff);
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out[8] = userid & 0xff;
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write_dns(fd, q, out, sizeof(out));
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write_dns(fd, q, out, sizeof(out), users[userid].downenc);
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}
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static void
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@ -270,7 +271,7 @@ send_chunk(int dns_fd, int userid) {
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users[userid].outpacket.seqno & 7, users[userid].outpacket.fragment & 15,
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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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write_dns(dns_fd, &users[userid].q, pkt, datalen + 2, users[userid].downenc);
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users[userid].q.id = 0;
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if (users[userid].outpacket.len > 0 &&
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@ -360,10 +361,21 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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memcpy(&(users[userid].q), q, sizeof(struct query));
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users[userid].encoder = get_base32_encoder();
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users[userid].downenc = 'T';
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send_version_response(dns_fd, VERSION_ACK, users[userid].seed, userid, q);
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syslog(LOG_INFO, "accepted version for user #%d from %s",
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userid, inet_ntoa(tempin->sin_addr));
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users[userid].q.id = 0;
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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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users[userid].outpacket.seqno = 0;
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users[userid].outpacket.fragment = 0;
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users[userid].inpacket.len = 0;
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users[userid].inpacket.offset = 0;
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users[userid].inpacket.seqno = 0;
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users[userid].inpacket.fragment = 0;
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users[userid].fragsize = 100; /* very safe */
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} else {
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/* No space for another user */
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send_version_response(dns_fd, VERSION_FULL, created_users, 0, q);
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@ -382,7 +394,7 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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userid = unpacked[0];
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if (check_user_and_ip(userid, q) != 0) {
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write_dns(dns_fd, q, "BADIP", 5);
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write_dns(dns_fd, q, "BADIP", 5, 'T');
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syslog(LOG_WARNING, "dropped login request from user #%d from unexpected source %s",
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userid, inet_ntoa(((struct sockaddr_in *) &q->from)->sin_addr));
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return;
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@ -401,14 +413,14 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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read = snprintf(out, sizeof(out), "%s-%s-%d-%d",
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tmp[0], tmp[1], my_mtu, netmask);
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write_dns(dns_fd, q, out, read);
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write_dns(dns_fd, q, out, read, users[userid].downenc);
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q->id = 0;
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syslog(LOG_NOTICE, "accepted password from user #%d, given IP %s", userid, tmp[1]);
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free(tmp[1]);
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free(tmp[0]);
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} else {
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write_dns(dns_fd, q, "LNAK", 4);
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write_dns(dns_fd, q, "LNAK", 4, 'T');
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syslog(LOG_WARNING, "rejected login request from user #%d from %s, bad password",
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userid, inet_ntoa(((struct sockaddr_in *) &q->from)->sin_addr));
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}
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@ -422,7 +434,7 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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userid = b32_8to5(in[1]);
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if (check_user_and_ip(userid, q) != 0) {
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write_dns(dns_fd, q, "BADIP", 5);
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write_dns(dns_fd, q, "BADIP", 5, 'T');
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return; /* illegal id */
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}
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@ -440,25 +452,26 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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reply[2] = (addr >> 16) & 0xFF;
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reply[3] = (addr >> 8) & 0xFF;
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reply[4] = (addr >> 0) & 0xFF;
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write_dns(dns_fd, q, reply, sizeof(reply));
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write_dns(dns_fd, q, reply, sizeof(reply), 'T');
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} else if(in[0] == 'Z' || in[0] == 'z') {
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/* Check for case conservation and chars not allowed according to RFC */
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/* Reply with received hostname as data */
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write_dns(dns_fd, q, in, domain_len);
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/* No userid here, reply with lowest-grade downenc */
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write_dns(dns_fd, q, in, domain_len, 'T');
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return;
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} else if(in[0] == 'S' || in[0] == 's') {
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int codec;
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struct encoder *enc;
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if (domain_len < 3) { /* len at least 3, example: "S15" */
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write_dns(dns_fd, q, "BADLEN", 6);
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write_dns(dns_fd, q, "BADLEN", 6, 'T');
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return;
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}
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userid = b32_8to5(in[1]);
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if (check_user_and_ip(userid, q) != 0) {
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write_dns(dns_fd, q, "BADIP", 5);
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write_dns(dns_fd, q, "BADIP", 5, 'T');
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return; /* illegal id */
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}
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@ -468,15 +481,49 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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case 5: /* 5 bits per byte = base32 */
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enc = get_base32_encoder();
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user_switch_codec(userid, enc);
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write_dns(dns_fd, q, enc->name, strlen(enc->name));
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write_dns(dns_fd, q, enc->name, strlen(enc->name), users[userid].downenc);
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break;
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case 6: /* 6 bits per byte = base64 */
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enc = get_base64_encoder();
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user_switch_codec(userid, enc);
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write_dns(dns_fd, q, enc->name, strlen(enc->name));
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write_dns(dns_fd, q, enc->name, strlen(enc->name), users[userid].downenc);
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break;
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default:
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write_dns(dns_fd, q, "BADCODEC", 8);
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write_dns(dns_fd, q, "BADCODEC", 8, users[userid].downenc);
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break;
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}
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return;
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} else if(in[0] == 'O' || in[0] == 'o') {
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if (domain_len != 4) { /* len = 4, example: "O1T." */
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write_dns(dns_fd, q, "BADLEN", 6, 'T');
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return;
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}
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userid = b32_8to5(in[1]);
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if (check_user_and_ip(userid, q) != 0) {
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write_dns(dns_fd, q, "BADIP", 5, 'T');
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return; /* illegal id */
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}
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switch (in[2]) {
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case 'T':
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case 't':
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users[userid].downenc = 'T';
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write_dns(dns_fd, q, "Base32", 6, users[userid].downenc);
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break;
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case 'S':
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case 's':
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users[userid].downenc = 'S';
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write_dns(dns_fd, q, "Base64", 6, users[userid].downenc);
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break;
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case 'R':
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case 'r':
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users[userid].downenc = 'R';
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write_dns(dns_fd, q, "Raw", 3, users[userid].downenc);
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break;
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default:
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write_dns(dns_fd, q, "BADCODEC", 8, users[userid].downenc);
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break;
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}
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return;
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@ -486,20 +533,26 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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/* Downstream fragsize probe packet */
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userid = (b32_8to5(in[1]) >> 1) & 15;
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if (check_user_and_ip(userid, q) != 0) {
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write_dns(dns_fd, q, "BADIP", 5);
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write_dns(dns_fd, q, "BADIP", 5, 'T');
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return; /* illegal id */
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}
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req_frag_size = ((b32_8to5(in[1]) & 1) << 10) | ((b32_8to5(in[2]) & 31) << 5) | (b32_8to5(in[3]) & 31);
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if (req_frag_size < 2 || req_frag_size > 2047) {
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write_dns(dns_fd, q, "BADFRAG", 7);
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write_dns(dns_fd, q, "BADFRAG", 7, users[userid].downenc);
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} else {
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char buf[2048];
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int i;
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unsigned int v = (unsigned int) rand();
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memset(buf, 0, sizeof(buf));
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buf[0] = (req_frag_size >> 8) & 0xff;
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buf[1] = req_frag_size & 0xff;
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write_dns(dns_fd, q, buf, req_frag_size);
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/* make checkable pseudo-random sequence */
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buf[2] = 107;
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for (i = 3; i < 2048; i++, v += 107)
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buf[i] = (char) (v & 0xff);
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write_dns(dns_fd, q, buf, req_frag_size, users[userid].downenc);
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}
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return;
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} else if(in[0] == 'N' || in[0] == 'n') {
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@ -509,16 +562,16 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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/* Downstream fragsize packet */
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userid = unpacked[0];
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if (check_user_and_ip(userid, q) != 0) {
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write_dns(dns_fd, q, "BADIP", 5);
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write_dns(dns_fd, q, "BADIP", 5, 'T');
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return; /* illegal id */
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}
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max_frag_size = ((unpacked[1] & 0xff) << 8) | (unpacked[2] & 0xff);
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if (max_frag_size < 2) {
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write_dns(dns_fd, q, "BADFRAG", 7);
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write_dns(dns_fd, q, "BADFRAG", 7, users[userid].downenc);
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} else {
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users[userid].fragsize = max_frag_size;
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write_dns(dns_fd, q, &unpacked[1], 2);
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write_dns(dns_fd, q, &unpacked[1], 2, users[userid].downenc);
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}
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return;
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} else if(in[0] == 'P' || in[0] == 'p') {
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@ -529,7 +582,7 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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/* Ping packet, store userid */
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userid = unpacked[0];
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if (check_user_and_ip(userid, q) != 0) {
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write_dns(dns_fd, q, "BADIP", 5);
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write_dns(dns_fd, q, "BADIP", 5, 'T');
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return; /* illegal id */
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}
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@ -564,7 +617,7 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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userid = code;
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/* Check user and sending ip number */
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if (check_user_and_ip(userid, q) != 0) {
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write_dns(dns_fd, q, "BADIP", 5);
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write_dns(dns_fd, q, "BADIP", 5, 'T');
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} else {
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/* Decode data header */
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int up_seq = (b32_8to5(in[1]) >> 2) & 7;
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@ -637,6 +690,10 @@ handle_ns_request(int dns_fd, struct query *q)
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}
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len = dns_encode_ns_response(buf, sizeof(buf), q, topdomain);
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if (len < 1) {
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warnx("dns_encode_ns_response doesn't fit");
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return;
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}
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if (debug >= 2) {
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struct sockaddr_in *tempin;
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@ -659,6 +716,10 @@ forward_query(int bind_fd, struct query *q)
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in_addr_t newaddr;
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len = dns_encode(buf, sizeof(buf), q, QR_QUERY, q->name, strlen(q->name));
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if (len < 1) {
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warnx("dns_encode doesn't fit");
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return;
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}
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/* Store sockaddr for q->id */
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memcpy(&(fwq.addr), &(q->from), q->fromlen);
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@ -755,8 +816,14 @@ tunnel_dns(int tun_fd, int dns_fd, int bind_fd)
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if (inside_topdomain) {
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/* This is a query we can handle */
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switch (q.type) {
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case T_NULL:
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case T_CNAME:
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case T_A:
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case T_MX:
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case T_TXT:
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/* encoding is "transparent" here */
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handle_null_request(tun_fd, dns_fd, &q, domain_len);
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break;
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case T_NS:
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@ -1044,12 +1111,91 @@ read_dns(int fd, int tun_fd, struct query *q) /* FIXME: tun_fd is because of raw
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}
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static void
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write_dns(int fd, struct query *q, char *data, int datalen)
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write_dns(int fd, struct query *q, char *data, int datalen, char downenc)
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{
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char buf[64*1024];
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int len;
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int len = 0;
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len = dns_encode(buf, sizeof(buf), q, QR_ANSWER, data, datalen);
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if (q->type == T_CNAME || q->type == T_A || q->type == T_MX) {
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static int td1 = 0;
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static int td2 = 0;
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char cnamebuf[1024]; /* max 255 */
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size_t space;
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char *b;
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/* Make a rotating topdomain to prevent filtering */
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td1+=3;
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td2+=7;
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if (td1>=26) td1-=26;
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if (td2>=25) td2-=25;
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/* encode data,datalen to CNAME/MX answer */
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/* (adapted from build_hostname() in iodine.c) */
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space = MIN(0xFF, sizeof(cnamebuf)) - 4 - 2;
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/* -1 encoding type, -3 ".xy", -2 for safety */
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memset(cnamebuf, 0, sizeof(cnamebuf));
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if (downenc == 'S') {
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cnamebuf[0] = 'I';
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if (!b64->places_dots())
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space -= (space / 57); /* space for dots */
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b64->encode(cnamebuf+1, &space, data, datalen);
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if (!b64->places_dots())
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inline_dotify(cnamebuf, sizeof(cnamebuf), 57);
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} else {
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cnamebuf[0] = 'H';
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if (!b32->places_dots())
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space -= (space / 57); /* space for dots */
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b32->encode(cnamebuf+1, &space, data, datalen);
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if (!b32->places_dots())
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inline_dotify(cnamebuf, sizeof(cnamebuf), 57);
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}
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/* Add dot (if it wasn't there already) and topdomain */
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b = cnamebuf;
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b += strlen(cnamebuf);
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if (*b != '.')
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*b++ = '.';
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*b = 'a' + td1;
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b++;
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*b = 'a' + td2;
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b++;
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*b = '\0';
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len = dns_encode(buf, sizeof(buf), q, QR_ANSWER, cnamebuf, sizeof(cnamebuf));
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}
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else if (q->type == T_TXT) {
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/* TXT with base32 */
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char txtbuf[64*1024];
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size_t space = sizeof(txtbuf) - 1;;
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memset(txtbuf, 0, sizeof(txtbuf));
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if (downenc == 'S') {
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txtbuf[0] = 'S'; /* plain base64(Sixty-four) */
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len = b64->encode(txtbuf+1, &space, data, datalen);
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}
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else if (downenc == 'R') {
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txtbuf[0] = 'R'; /* Raw binary data */
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len = MIN(datalen, sizeof(txtbuf) - 1);
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memcpy(txtbuf + 1, data, len);
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} else {
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txtbuf[0] = 'T'; /* plain base32(Thirty-two) */
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len = b32->encode(txtbuf+1, &space, data, datalen);
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}
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len = dns_encode(buf, sizeof(buf), q, QR_ANSWER, txtbuf, len+1);
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} else {
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/* Normal NULL-record encode */
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len = dns_encode(buf, sizeof(buf), q, QR_ANSWER, data, datalen);
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}
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if (len < 1) {
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warnx("dns_encode doesn't fit");
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return;
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}
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if (debug >= 2) {
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struct sockaddr_in *tempin;
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@ -1166,6 +1312,7 @@ main(int argc, char **argv)
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pidfile = NULL;
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b32 = get_base32_encoder();
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b64 = get_base64_encoder();
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retval = 0;
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