| /* $Id$ */ |
| /* |
| * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) |
| * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| #include <pjlib-util/dns_server.h> |
| #include <pjlib-util/errno.h> |
| #include <pj/activesock.h> |
| #include <pj/assert.h> |
| #include <pj/list.h> |
| #include <pj/log.h> |
| #include <pj/pool.h> |
| #include <pj/string.h> |
| |
| #define THIS_FILE "dns_server.c" |
| #define MAX_ANS 16 |
| #define MAX_PKT 1500 |
| #define MAX_LABEL 32 |
| |
| struct label_tab |
| { |
| unsigned count; |
| |
| struct { |
| unsigned pos; |
| pj_str_t label; |
| } a[MAX_LABEL]; |
| }; |
| |
| struct rr |
| { |
| PJ_DECL_LIST_MEMBER(struct rr); |
| pj_dns_parsed_rr rec; |
| }; |
| |
| |
| struct pj_dns_server |
| { |
| pj_pool_t *pool; |
| pj_pool_factory *pf; |
| pj_activesock_t *asock; |
| pj_ioqueue_op_key_t send_key; |
| struct rr rr_list; |
| }; |
| |
| |
| static pj_bool_t on_data_recvfrom(pj_activesock_t *asock, |
| void *data, |
| pj_size_t size, |
| const pj_sockaddr_t *src_addr, |
| int addr_len, |
| pj_status_t status); |
| |
| |
| PJ_DEF(pj_status_t) pj_dns_server_create( pj_pool_factory *pf, |
| pj_ioqueue_t *ioqueue, |
| int af, |
| unsigned port, |
| unsigned flags, |
| pj_dns_server **p_srv) |
| { |
| pj_pool_t *pool; |
| pj_dns_server *srv; |
| pj_sockaddr sock_addr; |
| pj_activesock_cb sock_cb; |
| pj_status_t status; |
| |
| PJ_ASSERT_RETURN(pf && ioqueue && p_srv && flags==0, PJ_EINVAL); |
| PJ_ASSERT_RETURN(af==pj_AF_INET() || af==pj_AF_INET6(), PJ_EINVAL); |
| |
| pool = pj_pool_create(pf, "dnsserver", 256, 256, NULL); |
| srv = (pj_dns_server*) PJ_POOL_ZALLOC_T(pool, pj_dns_server); |
| srv->pool = pool; |
| srv->pf = pf; |
| pj_list_init(&srv->rr_list); |
| |
| pj_bzero(&sock_addr, sizeof(sock_addr)); |
| sock_addr.addr.sa_family = (pj_uint16_t)af; |
| pj_sockaddr_set_port(&sock_addr, (pj_uint16_t)port); |
| |
| pj_bzero(&sock_cb, sizeof(sock_cb)); |
| sock_cb.on_data_recvfrom = &on_data_recvfrom; |
| |
| status = pj_activesock_create_udp(pool, &sock_addr, NULL, ioqueue, |
| &sock_cb, srv, &srv->asock, NULL); |
| if (status != PJ_SUCCESS) |
| goto on_error; |
| |
| pj_ioqueue_op_key_init(&srv->send_key, sizeof(srv->send_key)); |
| |
| status = pj_activesock_start_recvfrom(srv->asock, pool, MAX_PKT, 0); |
| if (status != PJ_SUCCESS) |
| goto on_error; |
| |
| *p_srv = srv; |
| return PJ_SUCCESS; |
| |
| on_error: |
| pj_dns_server_destroy(srv); |
| return status; |
| } |
| |
| |
| PJ_DEF(pj_status_t) pj_dns_server_destroy(pj_dns_server *srv) |
| { |
| PJ_ASSERT_RETURN(srv, PJ_EINVAL); |
| |
| if (srv->asock) { |
| pj_activesock_close(srv->asock); |
| srv->asock = NULL; |
| } |
| |
| if (srv->pool) { |
| pj_pool_t *pool = srv->pool; |
| srv->pool = NULL; |
| pj_pool_release(pool); |
| } |
| |
| return PJ_SUCCESS; |
| } |
| |
| |
| static struct rr* find_rr( pj_dns_server *srv, |
| unsigned dns_class, |
| unsigned type /* pj_dns_type */, |
| const pj_str_t *name) |
| { |
| struct rr *r; |
| |
| r = srv->rr_list.next; |
| while (r != &srv->rr_list) { |
| if (r->rec.dnsclass == dns_class && r->rec.type == type && |
| pj_stricmp(&r->rec.name, name)==0) |
| { |
| return r; |
| } |
| r = r->next; |
| } |
| |
| return NULL; |
| } |
| |
| |
| PJ_DEF(pj_status_t) pj_dns_server_add_rec( pj_dns_server *srv, |
| unsigned count, |
| const pj_dns_parsed_rr rr_param[]) |
| { |
| unsigned i; |
| |
| PJ_ASSERT_RETURN(srv && count && rr_param, PJ_EINVAL); |
| |
| for (i=0; i<count; ++i) { |
| struct rr *rr; |
| |
| PJ_ASSERT_RETURN(find_rr(srv, rr_param[i].dnsclass, rr_param[i].type, |
| &rr_param[i].name) == NULL, |
| PJ_EEXISTS); |
| |
| rr = (struct rr*) PJ_POOL_ZALLOC_T(srv->pool, struct rr); |
| pj_memcpy(&rr->rec, &rr_param[i], sizeof(pj_dns_parsed_rr)); |
| |
| pj_list_push_back(&srv->rr_list, rr); |
| } |
| |
| return PJ_SUCCESS; |
| } |
| |
| |
| PJ_DEF(pj_status_t) pj_dns_server_del_rec( pj_dns_server *srv, |
| int dns_class, |
| pj_dns_type type, |
| const pj_str_t *name) |
| { |
| struct rr *rr; |
| |
| PJ_ASSERT_RETURN(srv && type && name, PJ_EINVAL); |
| |
| rr = find_rr(srv, dns_class, type, name); |
| if (!rr) |
| return PJ_ENOTFOUND; |
| |
| pj_list_erase(rr); |
| |
| return PJ_SUCCESS; |
| } |
| |
| |
| static void write16(pj_uint8_t *p, pj_uint16_t val) |
| { |
| p[0] = (pj_uint8_t)(val >> 8); |
| p[1] = (pj_uint8_t)(val & 0xFF); |
| } |
| |
| static void write32(pj_uint8_t *p, pj_uint32_t val) |
| { |
| val = pj_htonl(val); |
| pj_memcpy(p, &val, 4); |
| } |
| |
| static int print_name(pj_uint8_t *pkt, int size, |
| pj_uint8_t *pos, const pj_str_t *name, |
| struct label_tab *tab) |
| { |
| pj_uint8_t *p = pos; |
| const char *endlabel, *endname; |
| unsigned i; |
| pj_str_t label; |
| |
| /* Check if name is in the table */ |
| for (i=0; i<tab->count; ++i) { |
| if (pj_strcmp(&tab->a[i].label, name)==0) |
| break; |
| } |
| |
| if (i != tab->count) { |
| write16(p, (pj_uint16_t)(tab->a[i].pos | (0xc0 << 8))); |
| return 2; |
| } else { |
| if (tab->count < MAX_LABEL) { |
| tab->a[tab->count].pos = (unsigned)(p-pkt); |
| tab->a[tab->count].label.ptr = (char*)(p+1); |
| tab->a[tab->count].label.slen = name->slen; |
| ++tab->count; |
| } |
| } |
| |
| endlabel = name->ptr; |
| endname = name->ptr + name->slen; |
| |
| label.ptr = (char*)name->ptr; |
| |
| while (endlabel != endname) { |
| |
| while (endlabel != endname && *endlabel != '.') |
| ++endlabel; |
| |
| label.slen = (endlabel - label.ptr); |
| |
| if (size < label.slen+1) |
| return -1; |
| |
| *p = (pj_uint8_t)label.slen; |
| pj_memcpy(p+1, label.ptr, label.slen); |
| |
| size -= (int)(label.slen+1); |
| p += (label.slen+1); |
| |
| if (endlabel != endname && *endlabel == '.') |
| ++endlabel; |
| label.ptr = (char*)endlabel; |
| } |
| |
| if (size == 0) |
| return -1; |
| |
| *p++ = '\0'; |
| |
| return (int)(p-pos); |
| } |
| |
| static int print_rr(pj_uint8_t *pkt, int size, pj_uint8_t *pos, |
| const pj_dns_parsed_rr *rr, struct label_tab *tab) |
| { |
| pj_uint8_t *p = pos; |
| int len; |
| |
| len = print_name(pkt, size, pos, &rr->name, tab); |
| if (len < 0) |
| return -1; |
| |
| p += len; |
| size -= len; |
| |
| if (size < 8) |
| return -1; |
| |
| pj_assert(rr->dnsclass == 1); |
| |
| write16(p+0, (pj_uint16_t)rr->type); /* type */ |
| write16(p+2, (pj_uint16_t)rr->dnsclass); /* class */ |
| write32(p+4, rr->ttl); /* TTL */ |
| |
| p += 8; |
| size -= 8; |
| |
| if (rr->type == PJ_DNS_TYPE_A) { |
| |
| if (size < 6) |
| return -1; |
| |
| /* RDLEN is 4 */ |
| write16(p, 4); |
| |
| /* Address */ |
| pj_memcpy(p+2, &rr->rdata.a.ip_addr, 4); |
| |
| p += 6; |
| size -= 6; |
| |
| } else if (rr->type == PJ_DNS_TYPE_CNAME || |
| rr->type == PJ_DNS_TYPE_NS || |
| rr->type == PJ_DNS_TYPE_PTR) { |
| |
| if (size < 4) |
| return -1; |
| |
| len = print_name(pkt, size-2, p+2, &rr->rdata.cname.name, tab); |
| if (len < 0) |
| return -1; |
| |
| write16(p, (pj_uint16_t)len); |
| |
| p += (len + 2); |
| size -= (len + 2); |
| |
| } else if (rr->type == PJ_DNS_TYPE_SRV) { |
| |
| if (size < 10) |
| return -1; |
| |
| write16(p+2, rr->rdata.srv.prio); /* Priority */ |
| write16(p+4, rr->rdata.srv.weight); /* Weight */ |
| write16(p+6, rr->rdata.srv.port); /* Port */ |
| |
| /* Target */ |
| len = print_name(pkt, size-8, p+8, &rr->rdata.srv.target, tab); |
| if (len < 0) |
| return -1; |
| |
| /* RDLEN */ |
| write16(p, (pj_uint16_t)(len + 6)); |
| |
| p += (len + 8); |
| size -= (len + 8); |
| |
| } else { |
| pj_assert(!"Not supported"); |
| return -1; |
| } |
| |
| return (int)(p-pos); |
| } |
| |
| static int print_packet(const pj_dns_parsed_packet *rec, pj_uint8_t *pkt, |
| int size) |
| { |
| pj_uint8_t *p = pkt; |
| struct label_tab tab; |
| int i, len; |
| |
| tab.count = 0; |
| |
| pj_assert(sizeof(pj_dns_hdr)==12); |
| if (size < (int)sizeof(pj_dns_hdr)) |
| return -1; |
| |
| /* Initialize header */ |
| write16(p+0, rec->hdr.id); |
| write16(p+2, rec->hdr.flags); |
| write16(p+4, rec->hdr.qdcount); |
| write16(p+6, rec->hdr.anscount); |
| write16(p+8, rec->hdr.nscount); |
| write16(p+10, rec->hdr.arcount); |
| |
| p = pkt + sizeof(pj_dns_hdr); |
| size -= sizeof(pj_dns_hdr); |
| |
| /* Print queries */ |
| for (i=0; i<rec->hdr.qdcount; ++i) { |
| |
| len = print_name(pkt, size, p, &rec->q[i].name, &tab); |
| if (len < 0) |
| return -1; |
| |
| p += len; |
| size -= len; |
| |
| if (size < 4) |
| return -1; |
| |
| /* Set type */ |
| write16(p+0, (pj_uint16_t)rec->q[i].type); |
| |
| /* Set class (IN=1) */ |
| pj_assert(rec->q[i].dnsclass == 1); |
| write16(p+2, rec->q[i].dnsclass); |
| |
| p += 4; |
| } |
| |
| /* Print answers */ |
| for (i=0; i<rec->hdr.anscount; ++i) { |
| len = print_rr(pkt, size, p, &rec->ans[i], &tab); |
| if (len < 0) |
| return -1; |
| |
| p += len; |
| size -= len; |
| } |
| |
| /* Print NS records */ |
| for (i=0; i<rec->hdr.nscount; ++i) { |
| len = print_rr(pkt, size, p, &rec->ns[i], &tab); |
| if (len < 0) |
| return -1; |
| |
| p += len; |
| size -= len; |
| } |
| |
| /* Print additional records */ |
| for (i=0; i<rec->hdr.arcount; ++i) { |
| len = print_rr(pkt, size, p, &rec->arr[i], &tab); |
| if (len < 0) |
| return -1; |
| |
| p += len; |
| size -= len; |
| } |
| |
| return (int)(p - pkt); |
| } |
| |
| |
| static pj_bool_t on_data_recvfrom(pj_activesock_t *asock, |
| void *data, |
| pj_size_t size, |
| const pj_sockaddr_t *src_addr, |
| int addr_len, |
| pj_status_t status) |
| { |
| pj_dns_server *srv; |
| pj_pool_t *pool; |
| pj_dns_parsed_packet *req; |
| pj_dns_parsed_packet ans; |
| struct rr *rr; |
| pj_ssize_t pkt_len; |
| unsigned i; |
| |
| if (status != PJ_SUCCESS) |
| return PJ_TRUE; |
| |
| srv = (pj_dns_server*) pj_activesock_get_user_data(asock); |
| pool = pj_pool_create(srv->pf, "dnssrvrx", 512, 256, NULL); |
| |
| status = pj_dns_parse_packet(pool, data, (unsigned)size, &req); |
| if (status != PJ_SUCCESS) { |
| char addrinfo[PJ_INET6_ADDRSTRLEN+10]; |
| pj_sockaddr_print(src_addr, addrinfo, sizeof(addrinfo), 3); |
| PJ_LOG(4,(THIS_FILE, "Error parsing query from %s", addrinfo)); |
| goto on_return; |
| } |
| |
| /* Init answer */ |
| pj_bzero(&ans, sizeof(ans)); |
| ans.hdr.id = req->hdr.id; |
| ans.hdr.qdcount = 1; |
| ans.q = (pj_dns_parsed_query*) PJ_POOL_ALLOC_T(pool, pj_dns_parsed_query); |
| pj_memcpy(ans.q, req->q, sizeof(pj_dns_parsed_query)); |
| |
| if (req->hdr.qdcount != 1) { |
| ans.hdr.flags = PJ_DNS_SET_RCODE(PJ_DNS_RCODE_FORMERR); |
| goto send_pkt; |
| } |
| |
| if (req->q[0].dnsclass != PJ_DNS_CLASS_IN) { |
| ans.hdr.flags = PJ_DNS_SET_RCODE(PJ_DNS_RCODE_NOTIMPL); |
| goto send_pkt; |
| } |
| |
| /* Find the record */ |
| rr = find_rr(srv, req->q->dnsclass, req->q->type, &req->q->name); |
| if (rr == NULL) { |
| ans.hdr.flags = PJ_DNS_SET_RCODE(PJ_DNS_RCODE_NXDOMAIN); |
| goto send_pkt; |
| } |
| |
| /* Init answer record */ |
| ans.hdr.anscount = 0; |
| ans.ans = (pj_dns_parsed_rr*) |
| pj_pool_calloc(pool, MAX_ANS, sizeof(pj_dns_parsed_rr)); |
| |
| /* DNS SRV query needs special treatment since it returns multiple |
| * records |
| */ |
| if (req->q->type == PJ_DNS_TYPE_SRV) { |
| struct rr *r; |
| |
| r = srv->rr_list.next; |
| while (r != &srv->rr_list) { |
| if (r->rec.dnsclass == req->q->dnsclass && |
| r->rec.type == PJ_DNS_TYPE_SRV && |
| pj_stricmp(&r->rec.name, &req->q->name)==0 && |
| ans.hdr.anscount < MAX_ANS) |
| { |
| pj_memcpy(&ans.ans[ans.hdr.anscount], &r->rec, |
| sizeof(pj_dns_parsed_rr)); |
| ++ans.hdr.anscount; |
| } |
| r = r->next; |
| } |
| } else { |
| /* Otherwise just copy directly from the server record */ |
| pj_memcpy(&ans.ans[ans.hdr.anscount], &rr->rec, |
| sizeof(pj_dns_parsed_rr)); |
| ++ans.hdr.anscount; |
| } |
| |
| /* For each CNAME entry, add A entry */ |
| for (i=0; i<ans.hdr.anscount && ans.hdr.anscount < MAX_ANS; ++i) { |
| if (ans.ans[i].type == PJ_DNS_TYPE_CNAME) { |
| struct rr *r; |
| |
| r = find_rr(srv, ans.ans[i].dnsclass, PJ_DNS_TYPE_A, |
| &ans.ans[i].name); |
| pj_memcpy(&ans.ans[ans.hdr.anscount], &r->rec, |
| sizeof(pj_dns_parsed_rr)); |
| ++ans.hdr.anscount; |
| } |
| } |
| |
| send_pkt: |
| pkt_len = print_packet(&ans, (pj_uint8_t*)data, MAX_PKT); |
| if (pkt_len < 1) { |
| PJ_LOG(4,(THIS_FILE, "Error: answer too large")); |
| goto on_return; |
| } |
| |
| status = pj_activesock_sendto(srv->asock, &srv->send_key, data, &pkt_len, |
| 0, src_addr, addr_len); |
| if (status != PJ_SUCCESS && status != PJ_EPENDING) { |
| PJ_LOG(4,(THIS_FILE, "Error sending answer, status=%d", status)); |
| goto on_return; |
| } |
| |
| on_return: |
| pj_pool_release(pool); |
| return PJ_TRUE; |
| } |
| |