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https://github.com/yarrick/iodine.git
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Fix issue #33, respond to NS requests
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parent
d40c464ac1
commit
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@ -19,6 +19,8 @@ CHANGES:
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- Added capability to forward DNS queries outside tunnel domain to
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a nameserver on localhost. Use -b port to enable.
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- iodine client now shuts down if it detects a server restart.
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- iodined now replies to NS request on its own domain, fixes issue #33.
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The destination IP address is sent as reply.
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2008-08-06: 0.4.2 "Opened Zone"
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- Applied a few small patches from Maxim Bourmistrov and Gregor Herrmann
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79
src/dns.c
79
src/dns.c
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@ -98,6 +98,85 @@ dns_encode(char *buf, size_t buflen, struct query *q, qr_t qr, char *data, size_
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return len;
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}
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int
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dns_encode_ns_response(char *buf, size_t buflen, struct query *q, char *topdomain)
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{
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HEADER *header;
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int len;
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short name;
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short topname;
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short nsname;
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char *domain;
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int domain_len;
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char *p;
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memset(buf, 0, buflen);
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header = (HEADER*)buf;
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header->id = htons(q->id);
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header->qr = 1;
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header->opcode = 0;
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header->aa = 1;
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header->tc = 0;
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header->rd = 0;
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header->ra = 0;
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p = buf + sizeof(HEADER);
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header->qdcount = htons(1);
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header->ancount = htons(1);
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header->arcount = htons(1);
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/* pointer to start of name */
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name = 0xc000 | ((p - buf) & 0x3fff);
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domain = strstr(q->name, topdomain);
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if (domain) {
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domain_len = (int) (domain - q->name);
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} else {
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return -1;
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}
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/* pointer to start of topdomain */
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topname = 0xc000 | ((p - buf + domain_len) & 0x3fff);
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/* Query section */
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putname(&p, sizeof(q->name), q->name); /* Name */
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putshort(&p, q->type); /* Type */
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putshort(&p, C_IN); /* Class */
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/* Answer section */
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putshort(&p, name); /* Name */
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putshort(&p, q->type); /* Type */
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putshort(&p, C_IN); /* Class */
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putlong(&p, 0x3ea7d011); /* TTL */
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putshort(&p, 5); /* Data length */
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/* pointer to ns.topdomain */
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nsname = 0xc000 | ((p - buf) & 0x3fff);
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putbyte(&p, 2);
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putbyte(&p, 'n');
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putbyte(&p, 's');
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putshort(&p, topname); /* Name Server */
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/* Additional data (A-record of NS server) */
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putshort(&p, nsname); /* Name Server */
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putshort(&p, T_A); /* Type */
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putshort(&p, C_IN); /* Class */
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putlong(&p, 0x3ea7d011); /* TTL */
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putshort(&p, 4); /* Data length */
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/* ugly hack to output IP address */
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domain = (char *) &q->destination;
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putbyte(&p, *domain++);
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putbyte(&p, *domain++);
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putbyte(&p, *domain++);
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putbyte(&p, *domain);
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len = p - buf;
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return len;
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}
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short
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dns_get_id(char *packet, size_t packetlen)
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{
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@ -25,6 +25,7 @@ typedef enum {
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} qr_t;
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int dns_encode(char *, size_t, struct query *, qr_t, char *, size_t);
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int dns_encode_ns_response(char *buf, size_t buflen, struct query *q, char *topdomain);
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short dns_get_id(char *packet, size_t packetlen);
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int dns_decode(char *, size_t, struct query *, qr_t, char *, size_t);
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@ -333,6 +333,19 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len)
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}
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}
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static void
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handle_ns_request(int dns_fd, struct query *q)
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{
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char buf[64*1024];
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int len;
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len = dns_encode_ns_response(buf, sizeof(buf), q, topdomain);
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if (sendto(dns_fd, buf, len, 0, (struct sockaddr*)&q->from, q->fromlen) <= 0) {
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warn("ns reply send error");
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}
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}
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static void
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forward_query(int bind_fd, struct query *q)
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{
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@ -443,6 +456,9 @@ tunnel_dns(int tun_fd, int dns_fd, int bind_fd)
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case T_NULL:
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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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handle_ns_request(dns_fd, &q);
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break;
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default:
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break;
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}
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