668 lines
15 KiB
C
668 lines
15 KiB
C
/* ---------------------------------------------------------------------- */
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/* S2 DNS server */
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#include <sofia-sip/sresolv.h>
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#include <sofia-resolv/sres_record.h>
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#include <sofia-sip/url.h>
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#include "s2dns.h"
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#include <string.h>
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#include <stdlib.h>
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#include <assert.h>
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extern uint16_t _sres_default_port; /* Ugly hack */
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static struct s2dns {
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su_root_t *root;
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su_socket_t socket;
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su_wait_t wait[1];
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int reg;
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int (*filter)(void *data, size_t len, void *userdata);
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void *userdata;
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} s2dns;
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static
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struct s2_dns_response {
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struct s2_dns_response *next;
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uint16_t qlen, dlen;
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struct m_header {
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/* Header defined in RFC 1035 section 4.1.1 (page 26) */
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uint16_t mh_id; /* Query ID */
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uint16_t mh_flags; /* Flags */
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uint16_t mh_qdcount; /* Question record count */
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uint16_t mh_ancount; /* Answer record count */
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uint16_t mh_nscount; /* Authority records count */
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uint16_t mh_arcount; /* Additional records count */
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} header[1];
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uint8_t data[1500];
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} *zonedata;
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enum {
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FLAGS_QR = (1 << 15),
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FLAGS_QUERY = (0 << 11),
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FLAGS_IQUERY = (1 << 11),
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FLAGS_STATUS = (2 << 11),
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FLAGS_OPCODE = (15 << 11), /* mask */
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FLAGS_AA = (1 << 10), /* */
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FLAGS_TC = (1 << 9),
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FLAGS_RD = (1 << 8),
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FLAGS_RA = (1 << 7),
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FLAGS_RCODE = (15 << 0), /* mask of return code */
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FLAGS_OK = 0, /* No error condition. */
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FLAGS_FORMAT_ERR = 1, /* Server could not interpret query. */
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FLAGS_SERVER_ERR = 2, /* Server error. */
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FLAGS_NAME_ERR = 3, /* No domain name. */
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FLAGS_UNIMPL_ERR = 4, /* Not implemented. */
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FLAGS_AUTH_ERR = 5, /* Refused */
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};
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uint32_t s2_dns_ttl = 3600;
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static int s2_dns_query(su_root_magic_t *magic,
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su_wait_t *w,
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su_wakeup_arg_t *arg);
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void s2_dns_setup(su_root_t *root)
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{
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int n;
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su_socket_t socket;
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su_wait_t *wait;
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su_sockaddr_t su[1];
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socklen_t sulen = sizeof su->su_sin;
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assert(root);
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memset(su, 0, sulen);
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su->su_len = sulen;
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su->su_family = AF_INET;
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/* su->su_port = htons(1053); */
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socket = su_socket(su->su_family, SOCK_DGRAM, 0);
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n = bind(socket, &su->su_sa, sulen); assert(n == 0);
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n = getsockname(socket, &su->su_sa, &sulen); assert(n == 0);
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_sres_default_port = ntohs(su->su_port);
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s2dns.root = root;
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wait = s2dns.wait;
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n = su_wait_create(wait, socket, SU_WAIT_IN); assert(n == 0);
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s2dns.reg = su_root_register(root, wait, s2_dns_query, NULL, 0);
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assert(s2dns.reg > 0);
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s2dns.socket = socket;
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}
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/* Set filter function */
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void
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s2_dns_set_filter(int (*filter)(void *data, size_t len, void *userdata),
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void *userdata)
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{
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s2dns.filter = filter;
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s2dns.userdata = userdata;
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}
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void
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s2_dns_teardown(void)
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{
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struct s2_dns_response *r, *next;
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su_root_deregister(s2dns.root, s2dns.reg), s2dns.reg = -1;
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su_close(s2dns.socket), s2dns.socket = -1;
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s2dns.root = NULL;
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for (r = zonedata, zonedata = NULL; r; r = next) {
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next = r->next;
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free(r);
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}
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}
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static int
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s2_dns_query(su_root_magic_t *magic,
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su_wait_t *w,
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su_wakeup_arg_t *arg)
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{
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union {
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struct m_header header[1];
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uint8_t buffer[1500];
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} request;
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ssize_t len;
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su_socket_t socket;
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su_sockaddr_t su[1];
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socklen_t sulen = sizeof su;
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uint16_t flags;
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struct s2_dns_response *r;
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size_t const hlen = sizeof r->header;
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(void)arg;
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socket = s2dns.socket;
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len = su_recvfrom(socket, request.buffer, sizeof request.buffer, 0,
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&su->su_sa, &sulen);
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flags = ntohs(request.header->mh_flags);
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if (len < (ssize_t)hlen)
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return 0;
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if ((flags & FLAGS_QR) == FLAGS_QR)
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return 0;
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if ((flags & FLAGS_RCODE) != FLAGS_OK)
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return 0;
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if ((flags & FLAGS_OPCODE) != FLAGS_QUERY
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|| ntohs(request.header->mh_qdcount) != 1) {
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flags |= FLAGS_QR | FLAGS_UNIMPL_ERR;
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request.header->mh_flags = htons(flags);
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if (!s2dns.filter || s2dns.filter(request.buffer, len, s2dns.userdata))
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su_sendto(socket, request.buffer, len, 0, &su->su_sa, sulen);
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return 0;
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}
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for (r = zonedata; r; r = r->next) {
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if (memcmp(r->data, request.buffer + hlen, r->qlen) == 0)
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break;
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}
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if (r) {
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flags |= FLAGS_QR | FLAGS_AA | FLAGS_OK;
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request.header->mh_flags = htons(flags);
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request.header->mh_ancount = htons(r->header->mh_ancount);
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request.header->mh_nscount = htons(r->header->mh_nscount);
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request.header->mh_arcount = htons(r->header->mh_arcount);
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memcpy(request.buffer + hlen + r->qlen,
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r->data + r->qlen,
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r->dlen - r->qlen);
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len = hlen + r->dlen;
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}
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else {
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flags |= FLAGS_QR | FLAGS_AA | FLAGS_NAME_ERR;
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}
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request.header->mh_flags = htons(flags);
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if (!s2dns.filter || s2dns.filter(request.buffer, len, s2dns.userdata))
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su_sendto(socket, request.buffer, len, 0, &su->su_sa, sulen);
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return 0;
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}
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static char const *default_domain;
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/** Set default domain suffix used with s2_dns_record() */
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char const *
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s2_dns_default(char const *domain)
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{
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assert(domain == NULL || strlen(domain));
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assert(domain == NULL || domain[strlen(domain) - 1] == '.');
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return default_domain = domain;
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}
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static void put_uint16(struct s2_dns_response *m, uint16_t h)
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{
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uint8_t *p = m->data + m->dlen;
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assert(m->dlen + (sizeof h) < sizeof m->data);
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p[0] = h >> 8; p[1] = h;
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m->dlen += (sizeof h);
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}
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static void put_uint32(struct s2_dns_response *m, uint32_t w)
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{
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uint8_t *p = m->data + m->dlen;
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assert(m->dlen + (sizeof w) < sizeof m->data);
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p[0] = w >> 24; p[1] = w >> 16; p[2] = w >> 8; p[3] = w;
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m->dlen += (sizeof w);
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}
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static void put_domain(struct s2_dns_response *m, char const *domain)
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{
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char const *label;
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size_t llen;
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if (domain && domain[0] == 0)
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domain = default_domain;
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/* Copy domain into query label at a time */
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for (label = domain; label && label[0]; label += llen) {
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assert(!(label[0] == '.' && label[1] != '\0'));
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llen = strcspn(label, ".");
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assert(llen < 64);
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assert(m->dlen + llen + 1 < sizeof m->data);
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m->data[m->dlen++] = (uint8_t)llen;
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if (llen == 0)
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return;
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memcpy(m->data + m->dlen, label, llen);
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m->dlen += (uint16_t)llen;
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if (label[llen] == '\0') {
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if (default_domain) {
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label = default_domain, llen = 0;
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continue;
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}
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break;
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}
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if (label[llen + 1])
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llen++;
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}
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assert(m->dlen < sizeof m->data);
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m->data[m->dlen++] = '\0';
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}
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static void put_string(struct s2_dns_response *m, char const *string)
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{
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uint8_t *p = m->data + m->dlen;
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size_t len = strlen(string);
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assert(len <= 255);
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assert(m->dlen + len + 1 < sizeof m->data);
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*p++ = (uint8_t)len;
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memcpy(p, string, len);
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m->dlen += len + 1;
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}
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static uint16_t put_len_at(struct s2_dns_response *m)
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{
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uint16_t at = m->dlen;
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assert(m->dlen + sizeof(at) < sizeof m->data);
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memset(m->data + m->dlen, 0, sizeof(at));
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m->dlen += sizeof(at);
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return at;
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}
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static void put_len(struct s2_dns_response *m, uint16_t start)
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{
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uint8_t *p = m->data + start;
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uint16_t len = m->dlen - (start + 2);
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p[0] = len >> 8; p[1] = len;
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}
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static void put_data(struct s2_dns_response *m, void const *data, uint16_t len)
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{
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assert(m->dlen + len < sizeof m->data);
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memcpy(m->data + m->dlen, data, len);
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m->dlen += len;
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}
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static void put_query(struct s2_dns_response *m, char const *domain,
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uint16_t qtype)
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{
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assert(m->header->mh_qdcount == 0);
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put_domain(m, domain), put_uint16(m, qtype), put_uint16(m, sres_class_in);
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m->header->mh_qdcount++;
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m->qlen = m->dlen;
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}
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static void put_a_record(struct s2_dns_response *m,
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char const *domain,
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struct in_addr addr)
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{
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uint16_t start;
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put_domain(m, domain);
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put_uint16(m, sres_type_a);
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put_uint16(m, sres_class_in);
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put_uint32(m, s2_dns_ttl);
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start = put_len_at(m);
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put_data(m, &addr, sizeof addr);
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put_len(m, start);
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}
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static void put_aaaa_record(struct s2_dns_response *m,
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char const *domain,
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struct in6_addr addr)
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{
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uint16_t start;
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put_domain(m, domain);
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put_uint16(m, sres_type_aaaa);
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put_uint16(m, sres_class_in);
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put_uint32(m, s2_dns_ttl);
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start = put_len_at(m);
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put_data(m, &addr, sizeof addr);
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put_len(m, start);
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}
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static void put_cname_record(struct s2_dns_response *m,
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char const *domain,
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char const *cname)
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{
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uint16_t start;
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put_domain(m, domain);
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put_uint16(m, sres_type_cname);
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put_uint16(m, sres_class_in);
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put_uint32(m, s2_dns_ttl);
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start = put_len_at(m);
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put_domain(m, cname);
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put_len(m, start);
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}
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static void put_srv_record(struct s2_dns_response *m,
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char const *domain,
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uint16_t prio, uint16_t weight,
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uint16_t port, char const *target)
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{
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uint16_t start;
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put_domain(m, domain);
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put_uint16(m, sres_type_srv);
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put_uint16(m, sres_class_in);
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put_uint32(m, s2_dns_ttl);
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start = put_len_at(m);
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put_uint16(m, prio);
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put_uint16(m, weight);
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put_uint16(m, port);
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put_domain(m, target);
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put_len(m, start);
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}
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static void put_naptr_record(struct s2_dns_response *m,
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char const *domain,
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uint16_t order, uint16_t preference,
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char const *flags,
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char const *services,
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char const *regexp,
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char const *replace)
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{
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uint16_t start;
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put_domain(m, domain);
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put_uint16(m, sres_type_naptr);
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put_uint16(m, sres_class_in);
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put_uint32(m, s2_dns_ttl);
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start = put_len_at(m);
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put_uint16(m, order);
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put_uint16(m, preference);
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put_string(m, flags);
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put_string(m, services);
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put_string(m, regexp);
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put_domain(m, replace);
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put_len(m, start);
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}
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static void put_srv_record_from_uri(struct s2_dns_response *m,
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char const *base,
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uint16_t prio, uint16_t weight,
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url_t const *uri, char const *server)
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{
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char domain[1024] = "none";
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char const *service = url_port(uri);
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uint16_t port;
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if (uri->url_type == url_sips) {
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strcpy(domain, "_sips._tcp.");
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}
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else if (uri->url_type == url_sip) {
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if (url_has_param(uri, "transport=udp")) {
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strcpy(domain, "_sip._udp.");
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}
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else if (url_has_param(uri, "transport=tcp")) {
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strcpy(domain, "_sip._tcp.");
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}
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}
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assert(strcmp(domain, "none"));
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strcat(domain, base);
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if (m->header->mh_qdcount == 0)
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put_query(m, domain, sres_type_srv);
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port = (uint16_t)strtoul(service, NULL, 10);
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put_srv_record(m, domain, prio, weight, port, server);
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}
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static
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void s2_add_to_zone(struct s2_dns_response *_r)
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{
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size_t size = offsetof(struct s2_dns_response, data[_r->dlen]);
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struct s2_dns_response *r = malloc(size); assert(r);
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memcpy(r, _r, size);
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r->next = zonedata;
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zonedata = r;
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}
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static void make_server(char *server, char const *prefix, char const *domain)
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{
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strcpy(server, prefix);
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if (strlen(server) == 0 || server[strlen(server) - 1] != '.') {
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strcat(server, ".");
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strcat(server, domain);
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}
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}
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/** Set up records for SIP server */
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void s2_dns_domain(char const *domain, int use_naptr,
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/* char *prefix, int priority, url_t const *uri, */
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...)
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{
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struct s2_dns_response m[1];
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char server[1024], target[1024];
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va_list va0, va;
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char const *prefix; int priority; url_t const *uri;
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struct in_addr localhost;
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assert(s2dns.reg != 0);
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su_inet_pton(AF_INET, "127.0.0.1", &localhost);
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va_start(va0, use_naptr);
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if (use_naptr) {
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memset(m, 0, sizeof m);
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put_query(m, domain, sres_type_naptr);
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va_copy(va, va0);
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for (;(prefix = va_arg(va, char *));) {
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char *services = NULL;
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priority = va_arg(va, int);
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uri = va_arg(va, url_t *);
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if (uri == NULL)
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continue;
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if (uri->url_type == url_sips) {
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services = "SIPS+D2T";
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strcpy(target, "_sips._tcp.");
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}
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else if (uri->url_type == url_sip) {
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if (url_has_param(uri, "transport=udp")) {
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services = "SIP+D2U";
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strcpy(target, "_sip._udp.");
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}
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else if (url_has_param(uri, "transport=tcp")) {
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services = "SIP+D2T";
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strcpy(target, "_sip._tcp.");
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}
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}
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strcat(target, domain);
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assert(services);
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put_naptr_record(m, domain, 1, priority, "s", services, "", target);
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m->header->mh_ancount++;
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}
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va_end(va);
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va_copy(va, va0);
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for (;(prefix = va_arg(va, char *));) {
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priority = va_arg(va, int);
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uri = va_arg(va, url_t *);
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if (uri == NULL)
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continue;
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make_server(server, prefix, domain);
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|
put_srv_record_from_uri(m, domain, priority, 10, uri, server);
|
|
m->header->mh_arcount++;
|
|
|
|
put_a_record(m, server, localhost);
|
|
m->header->mh_arcount++;
|
|
}
|
|
va_end(va);
|
|
|
|
s2_add_to_zone(m);
|
|
}
|
|
|
|
/* Add SRV records */
|
|
va_copy(va, va0);
|
|
for (;(prefix = va_arg(va, char *));) {
|
|
priority = va_arg(va, int);
|
|
uri = va_arg(va, url_t *);
|
|
if (uri == NULL)
|
|
continue;
|
|
|
|
make_server(server, prefix, domain);
|
|
|
|
memset(m, 0, sizeof m);
|
|
put_srv_record_from_uri(m, domain, priority, 10, uri, server);
|
|
m->header->mh_ancount++;
|
|
|
|
strcpy(server, prefix); strcat(server, domain);
|
|
|
|
put_a_record(m, server, localhost);
|
|
m->header->mh_arcount++;
|
|
|
|
s2_add_to_zone(m);
|
|
}
|
|
va_end(va);
|
|
|
|
/* Add A records */
|
|
va_copy(va, va0);
|
|
for (;(prefix = va_arg(va, char *));) {
|
|
(void)va_arg(va, int);
|
|
if (va_arg(va, url_t *) == NULL)
|
|
continue;
|
|
|
|
memset(m, 0, sizeof m);
|
|
make_server(server, prefix, domain);
|
|
|
|
put_query(m, server, sres_type_a);
|
|
put_a_record(m, server, localhost);
|
|
m->header->mh_ancount++;
|
|
|
|
s2_add_to_zone(m);
|
|
}
|
|
va_end(va);
|
|
|
|
va_end(va0);
|
|
}
|
|
|
|
/** Insert DNS response.
|
|
|
|
s2_dns_record("example.com", sres_type_naptr,
|
|
// order priority flags services regexp target
|
|
"", sres_type_naptr, 20, 50, "a", "SIP+D2U", "", "sip00",
|
|
"", sres_type_naptr, 20, 50, "a", "SIP+D2T", "", "sip00",
|
|
"", sres_type_naptr, 20, 50, "a", "SIPS+D2T", "", "sip00",
|
|
"sip00", sres_type_a, "12.13.14.15",
|
|
NULL);
|
|
*/
|
|
void s2_dns_record(
|
|
char const *qdomain, unsigned qtype,
|
|
/* unsigned atype, domain, */
|
|
...)
|
|
{
|
|
struct s2_dns_response m[1];
|
|
char const *domain;
|
|
va_list va;
|
|
unsigned atype;
|
|
unsigned ancount = 0, arcount = 0;
|
|
|
|
memset(m, 0, (sizeof m));
|
|
|
|
va_start(va, qtype);
|
|
|
|
put_query(m, qdomain, qtype);
|
|
|
|
for (domain = va_arg(va, char const *); domain; domain = va_arg(va, char const *)) {
|
|
if (!domain[0])
|
|
domain = qdomain;
|
|
|
|
if (strcmp(domain, "@") == 0)
|
|
domain = default_domain;
|
|
|
|
atype = va_arg(va, unsigned);
|
|
|
|
if (arcount == 0 &&
|
|
(atype == qtype || atype == sres_type_cname) &&
|
|
strcmp(qdomain, domain) == 0)
|
|
ancount++;
|
|
else
|
|
arcount++;
|
|
|
|
switch(atype) {
|
|
case sres_type_naptr:
|
|
{
|
|
unsigned order = va_arg(va, unsigned);
|
|
unsigned priority = va_arg(va, unsigned);
|
|
char const *flags = va_arg(va, char const *);
|
|
char const *services = va_arg(va, char const *);
|
|
char const *regexp = va_arg(va, char const *);
|
|
char const *target = va_arg(va, char const *);
|
|
|
|
put_naptr_record(m, domain, order, priority,
|
|
flags, services, regexp, target);
|
|
}
|
|
break;
|
|
case sres_type_srv:
|
|
{
|
|
unsigned priority = va_arg(va, unsigned);
|
|
unsigned weight = va_arg(va, unsigned);
|
|
unsigned port = va_arg(va, unsigned);
|
|
char const *target = va_arg(va, char const *);
|
|
|
|
put_srv_record(m, domain, priority, weight, port, target);
|
|
}
|
|
break;
|
|
case sres_type_aaaa:
|
|
#if SU_HAVE_IN6
|
|
{
|
|
char const *address = va_arg(va, char const *); /* target */
|
|
struct in6_addr aaaa;
|
|
|
|
inet_pton(AF_INET6, address, &aaaa);
|
|
|
|
put_aaaa_record(m, domain, aaaa);
|
|
}
|
|
break;
|
|
#endif
|
|
case sres_type_a:
|
|
{
|
|
char const *address = va_arg(va, char const *); /* target */
|
|
struct in_addr a;
|
|
|
|
inet_pton(AF_INET, address, &a);
|
|
|
|
put_a_record(m, domain, a);
|
|
}
|
|
break;
|
|
case sres_type_cname:
|
|
put_cname_record(m, domain, va_arg(va, char const *));
|
|
}
|
|
}
|
|
|
|
m->header->mh_ancount = ancount;
|
|
m->header->mh_arcount = arcount;
|
|
|
|
s2_add_to_zone(m);
|
|
|
|
va_end(va);
|
|
}
|