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/* $Id: dns_server.c 3553 2011-05-05 06:14:19Z nanang $ */
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* Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
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* Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#include <pjlib-util/dns_server.h>
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#include <pjlib-util/errno.h>
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#include <pj/activesock.h>
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#include <pj/assert.h>
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#include <pj/string.h>
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#define THIS_FILE "dns_server.c"
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PJ_DECL_LIST_MEMBER(struct rr);
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pj_activesock_t *asock;
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pj_ioqueue_op_key_t send_key;
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static pj_bool_t on_data_recvfrom(pj_activesock_t *asock,
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const pj_sockaddr_t *src_addr,
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PJ_DEF(pj_status_t) pj_dns_server_create( pj_pool_factory *pf,
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pj_ioqueue_t *ioqueue,
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pj_dns_server **p_srv)
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pj_sockaddr sock_addr;
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pj_activesock_cb sock_cb;
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PJ_ASSERT_RETURN(pf && ioqueue && p_srv && flags==0, PJ_EINVAL);
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PJ_ASSERT_RETURN(af==pj_AF_INET() || af==pj_AF_INET6(), PJ_EINVAL);
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pool = pj_pool_create(pf, "dnsserver", 256, 256, NULL);
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srv = (pj_dns_server*) PJ_POOL_ZALLOC_T(pool, pj_dns_server);
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pj_list_init(&srv->rr_list);
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pj_bzero(&sock_addr, sizeof(sock_addr));
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sock_addr.addr.sa_family = (pj_uint16_t)af;
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pj_sockaddr_set_port(&sock_addr, (pj_uint16_t)port);
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pj_bzero(&sock_cb, sizeof(sock_cb));
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sock_cb.on_data_recvfrom = &on_data_recvfrom;
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status = pj_activesock_create_udp(pool, &sock_addr, NULL, ioqueue,
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&sock_cb, srv, &srv->asock, NULL);
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if (status != PJ_SUCCESS)
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pj_ioqueue_op_key_init(&srv->send_key, sizeof(srv->send_key));
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status = pj_activesock_start_recvfrom(srv->asock, pool, MAX_PKT, 0);
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if (status != PJ_SUCCESS)
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pj_dns_server_destroy(srv);
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PJ_DEF(pj_status_t) pj_dns_server_destroy(pj_dns_server *srv)
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PJ_ASSERT_RETURN(srv, PJ_EINVAL);
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pj_activesock_close(srv->asock);
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pj_pool_t *pool = srv->pool;
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pj_pool_release(pool);
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static struct rr* find_rr( pj_dns_server *srv,
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unsigned type /* pj_dns_type */,
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const pj_str_t *name)
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r = srv->rr_list.next;
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while (r != &srv->rr_list) {
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if (r->rec.dnsclass == dns_class && r->rec.type == type &&
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pj_stricmp(&r->rec.name, name)==0)
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PJ_DEF(pj_status_t) pj_dns_server_add_rec( pj_dns_server *srv,
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const pj_dns_parsed_rr rr_param[])
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PJ_ASSERT_RETURN(srv && count && rr_param, PJ_EINVAL);
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for (i=0; i<count; ++i) {
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PJ_ASSERT_RETURN(find_rr(srv, rr_param[i].dnsclass, rr_param[i].type,
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&rr_param[i].name) == NULL,
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rr = (struct rr*) PJ_POOL_ZALLOC_T(srv->pool, struct rr);
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pj_memcpy(&rr->rec, &rr_param[i], sizeof(pj_dns_parsed_rr));
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pj_list_push_back(&srv->rr_list, rr);
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PJ_DEF(pj_status_t) pj_dns_server_del_rec( pj_dns_server *srv,
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const pj_str_t *name)
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PJ_ASSERT_RETURN(srv && type && name, PJ_EINVAL);
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rr = find_rr(srv, dns_class, type, name);
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static void write16(pj_uint8_t *p, pj_uint16_t val)
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p[0] = (pj_uint8_t)(val >> 8);
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p[1] = (pj_uint8_t)(val & 0xFF);
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static void write32(pj_uint8_t *p, pj_uint32_t val)
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pj_memcpy(p, &val, 4);
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static int print_name(pj_uint8_t *pkt, int size,
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pj_uint8_t *pos, const pj_str_t *name,
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struct label_tab *tab)
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const char *endlabel, *endname;
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/* Check if name is in the table */
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for (i=0; i<tab->count; ++i) {
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if (pj_strcmp(&tab->a[i].label, name)==0)
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if (i != tab->count) {
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write16(p, (pj_uint16_t)(tab->a[i].pos | (0xc0 << 8)));
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if (tab->count < MAX_LABEL) {
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tab->a[tab->count].pos = (p-pkt);
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tab->a[tab->count].label.ptr = (char*)(p+1);
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tab->a[tab->count].label.slen = name->slen;
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endlabel = name->ptr;
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endname = name->ptr + name->slen;
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label.ptr = (char*)name->ptr;
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while (endlabel != endname) {
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while (endlabel != endname && *endlabel != '.')
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label.slen = (endlabel - label.ptr);
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if (size < label.slen+1)
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*p = (pj_uint8_t)label.slen;
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pj_memcpy(p+1, label.ptr, label.slen);
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size -= (label.slen+1);
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if (endlabel != endname && *endlabel == '.')
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label.ptr = (char*)endlabel;
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static int print_rr(pj_uint8_t *pkt, int size, pj_uint8_t *pos,
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const pj_dns_parsed_rr *rr, struct label_tab *tab)
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len = print_name(pkt, size, pos, &rr->name, tab);
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pj_assert(rr->dnsclass == 1);
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write16(p+0, (pj_uint16_t)rr->type); /* type */
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write16(p+2, (pj_uint16_t)rr->dnsclass); /* class */
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write32(p+4, rr->ttl); /* TTL */
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if (rr->type == PJ_DNS_TYPE_A) {
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pj_memcpy(p+2, &rr->rdata.a.ip_addr, 4);
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} else if (rr->type == PJ_DNS_TYPE_CNAME ||
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rr->type == PJ_DNS_TYPE_NS ||
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rr->type == PJ_DNS_TYPE_PTR) {
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len = print_name(pkt, size-2, p+2, &rr->rdata.cname.name, tab);
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write16(p, (pj_uint16_t)len);
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} else if (rr->type == PJ_DNS_TYPE_SRV) {
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write16(p+2, rr->rdata.srv.prio); /* Priority */
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write16(p+4, rr->rdata.srv.weight); /* Weight */
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write16(p+6, rr->rdata.srv.port); /* Port */
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len = print_name(pkt, size-8, p+8, &rr->rdata.srv.target, tab);
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write16(p, (pj_uint16_t)(len + 6));
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pj_assert(!"Not supported");
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static int print_packet(const pj_dns_parsed_packet *rec, pj_uint8_t *pkt,
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struct label_tab tab;
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pj_assert(sizeof(pj_dns_hdr)==12);
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if (size < (int)sizeof(pj_dns_hdr))
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/* Initialize header */
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write16(p+0, rec->hdr.id);
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write16(p+2, rec->hdr.flags);
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write16(p+4, rec->hdr.qdcount);
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write16(p+6, rec->hdr.anscount);
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write16(p+8, rec->hdr.nscount);
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write16(p+10, rec->hdr.arcount);
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p = pkt + sizeof(pj_dns_hdr);
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size -= sizeof(pj_dns_hdr);
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for (i=0; i<rec->hdr.qdcount; ++i) {
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len = print_name(pkt, size, p, &rec->q[i].name, &tab);
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write16(p+0, (pj_uint16_t)rec->q[i].type);
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/* Set class (IN=1) */
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pj_assert(rec->q[i].dnsclass == 1);
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write16(p+2, rec->q[i].dnsclass);
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for (i=0; i<rec->hdr.anscount; ++i) {
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len = print_rr(pkt, size, p, &rec->ans[i], &tab);
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/* Print NS records */
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for (i=0; i<rec->hdr.nscount; ++i) {
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len = print_rr(pkt, size, p, &rec->ns[i], &tab);
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/* Print additional records */
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for (i=0; i<rec->hdr.arcount; ++i) {
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len = print_rr(pkt, size, p, &rec->arr[i], &tab);
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static pj_bool_t on_data_recvfrom(pj_activesock_t *asock,
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const pj_sockaddr_t *src_addr,
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pj_dns_parsed_packet *req;
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pj_dns_parsed_packet ans;
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if (status != PJ_SUCCESS)
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srv = (pj_dns_server*) pj_activesock_get_user_data(asock);
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pool = pj_pool_create(srv->pf, "dnssrvrx", 512, 256, NULL);
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status = pj_dns_parse_packet(pool, data, size, &req);
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if (status != PJ_SUCCESS) {
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char addrinfo[PJ_INET6_ADDRSTRLEN+10];
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pj_sockaddr_print(src_addr, addrinfo, sizeof(addrinfo), 3);
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PJ_LOG(4,(THIS_FILE, "Error parsing query from %s", addrinfo));
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pj_bzero(&ans, sizeof(ans));
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ans.hdr.id = req->hdr.id;
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ans.q = (pj_dns_parsed_query*) PJ_POOL_ALLOC_T(pool, pj_dns_parsed_query);
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pj_memcpy(ans.q, req->q, sizeof(pj_dns_parsed_query));
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if (req->hdr.qdcount != 1) {
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ans.hdr.flags = PJ_DNS_SET_RCODE(PJ_DNS_RCODE_FORMERR);
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if (req->q[0].dnsclass != PJ_DNS_CLASS_IN) {
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ans.hdr.flags = PJ_DNS_SET_RCODE(PJ_DNS_RCODE_NOTIMPL);
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/* Find the record */
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rr = find_rr(srv, req->q->dnsclass, req->q->type, &req->q->name);
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ans.hdr.flags = PJ_DNS_SET_RCODE(PJ_DNS_RCODE_NXDOMAIN);
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/* Init answer record */
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ans.hdr.anscount = 0;
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ans.ans = (pj_dns_parsed_rr*)
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pj_pool_calloc(pool, MAX_ANS, sizeof(pj_dns_parsed_rr));
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/* DNS SRV query needs special treatment since it returns multiple
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if (req->q->type == PJ_DNS_TYPE_SRV) {
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r = srv->rr_list.next;
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while (r != &srv->rr_list) {
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if (r->rec.dnsclass == req->q->dnsclass &&
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r->rec.type == PJ_DNS_TYPE_SRV &&
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pj_stricmp(&r->rec.name, &req->q->name)==0 &&
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ans.hdr.anscount < MAX_ANS)
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pj_memcpy(&ans.ans[ans.hdr.anscount], &r->rec,
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sizeof(pj_dns_parsed_rr));
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/* Otherwise just copy directly from the server record */
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pj_memcpy(&ans.ans[ans.hdr.anscount], &rr->rec,
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sizeof(pj_dns_parsed_rr));
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/* For each CNAME entry, add A entry */
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for (i=0; i<ans.hdr.anscount && ans.hdr.anscount < MAX_ANS; ++i) {
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if (ans.ans[i].type == PJ_DNS_TYPE_CNAME) {
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r = find_rr(srv, ans.ans[i].dnsclass, PJ_DNS_TYPE_A,
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pj_memcpy(&ans.ans[ans.hdr.anscount], &r->rec,
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sizeof(pj_dns_parsed_rr));
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pkt_len = print_packet(&ans, (pj_uint8_t*)data, MAX_PKT);
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PJ_LOG(4,(THIS_FILE, "Error: answer too large"));
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status = pj_activesock_sendto(srv->asock, &srv->send_key, data, &pkt_len,
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0, src_addr, addr_len);
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if (status != PJ_SUCCESS && status != PJ_EPENDING) {
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PJ_LOG(4,(THIS_FILE, "Error sending answer, status=%d", status));
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pj_pool_release(pool);