service.c

   1 /*
   2  * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <sys/types.h>
  15 #include <netinet/in.h>
  16 #include <arpa/nameser.h>
  17 #include <sys/socket.h>
  18 #include <netinet/in.h>
  19 #include <arpa/inet.h>
  20
  21 #include <resolv.h>
  22 #include <glob.h>
  23 #include <stdio.h>
  24 #include <time.h>
  25
  26 #include <uci.h>
  27 #include <uci_blob.h>
  28
  29 #include <libubox/avl.h>
  30 #include <libubox/uloop.h>
  31 #include <libubox/avl-cmp.h>
  32 #include <libubox/blobmsg_json.h>
  33
  34 #include "dns.h"
  35 #include "service.h"
  36 #include "util.h"
  37
  38 enum {
  39         SERVICE_PORT,
  40         SERVICE_TXT,
  41         __SERVICE_MAX,
  42 };
  43
  44 struct service {
  45         struct avl_node avl;
  46
  47         time_t t;
  48
  49         char *service;
  50         char *daemon;
  51         char *txt;
  52         int txt_len;
  53         int port;
  54         int active;
  55 };
  56
  57 static const struct blobmsg_policy service_policy[__SERVICE_MAX] = {
  58         [SERVICE_PORT] = { .name = "port", .type = BLOBMSG_TYPE_INT32 },
  59         [SERVICE_TXT] = { .name = "txt", .type = BLOBMSG_TYPE_ARRAY },
  60 };
  61
  62 static const struct uci_blob_param_list service_attr_list = {
  63         .n_params = __SERVICE_MAX,
  64         .params = service_policy,
  65 };
  66
  67 static struct blob_buf b;
  68 static struct avl_tree services;
  69 char *hostname = NULL;
  70 static char *sdudp =  "_services._dns-sd._udp.local";
  71 static char *sdtcp =  "_services._dns-sd._tcp.local";
  72
  73 char*
  74 service_name(char *domain)
  75 {
  76         static char buffer[256];
  77
  78         snprintf(buffer, sizeof(buffer), "%s.%s", hostname, domain);
  79
  80         return buffer;
  81 }
  82
  83 static void
  84 service_send_ptr(struct uloop_fd *u, struct service *s)
  85 {
  86         unsigned char buffer[MAX_NAME_LEN];
  87         char *host = service_name(s->service);
  88         int len = dn_comp(host, buffer, MAX_NAME_LEN, NULL, NULL);
  89
  90         if (len < 1)
  91                 return;
  92
  93         dns_add_answer(TYPE_PTR, buffer, len);
  94 }
  95
  96 static void
  97 service_send_ptr_c(struct uloop_fd *u, char *host)
  98 {
  99         unsigned char buffer[MAX_NAME_LEN];
 100         int len = dn_comp(host, buffer, MAX_NAME_LEN, NULL, NULL);
 101
 102         if (len < 1)
 103                 return;
 104
 105         dns_add_answer(TYPE_PTR, buffer, len);
 106 }
 107
 108 static void
 109 service_send_a(struct uloop_fd *u)
 110 {
 111         unsigned char buffer[MAX_NAME_LEN];
 112         char *host = service_name("local");
 113         int len = dn_comp(host, buffer, MAX_NAME_LEN, NULL, NULL);
 114         struct in_addr in;
 115
 116         if (!inet_aton(iface_ip, &in)) {
 117                 fprintf(stderr, "%s is not valid\n", iface_ip);
 118                 return;
 119         }
 120
 121         if (len < 1)
 122                 return;
 123
 124         dns_add_answer(TYPE_A, (uint8_t *) &in.s_addr, 4);
 125 }
 126
 127 static void
 128 service_send_srv(struct uloop_fd *u, struct service *s)
 129 {
 130         unsigned char buffer[MAX_NAME_LEN];
 131         struct dns_srv_data *sd;
 132         char *host = service_name("local");
 133         int len = dn_comp(host, buffer, MAX_NAME_LEN, NULL, NULL);
 134
 135         if (len < 1)
 136                 return;
 137
 138         sd = malloc(len + sizeof(struct dns_srv_data));
 139         if (!sd)
 140                 return;
 141
 142         memset(sd, 0, sizeof(struct dns_srv_data));
 143         sd->port = cpu_to_be16(s->port);
 144         memcpy(&sd[1], buffer, len);
 145         host = service_name(s->service);
 146         dns_add_answer(TYPE_SRV, (uint8_t *) sd, len + sizeof(struct dns_srv_data));
 147         free(sd);
 148 }
 149
 150 #define TOUT_LOOKUP     60
 151
 152 static int
 153 service_timeout(struct service *s)
 154 {
 155         time_t t = time(NULL);
 156
 157         if (t - s->t <= TOUT_LOOKUP)
 158                 return 0;
 159
 160         s->t = t;
 161
 162         return 1;
 163 }
 164
 165 void
 166 service_reply_a(struct uloop_fd *u, int type)
 167 {
 168         if (type != TYPE_A)
 169                 return;
 170
 171         dns_init_answer();
 172         service_send_a(u);
 173         dns_send_answer(u, service_name("local"));
 174 }
 175
 176 void
 177 service_reply(struct uloop_fd *u, char *match)
 178 {
 179         struct service *s;
 180
 181         avl_for_each_element(&services, s, avl) {
 182                 char *host = service_name(s->service);
 183                 char *service = strstr(host, "._");
 184
 185                 if (!s->active || !service || !service_timeout(s))
 186                         continue;
 187
 188                 service++;
 189
 190                 if (match && strcmp(match, s->service))
 191                         continue;
 192
 193                 dns_init_answer();
 194                 service_send_ptr(u, s);
 195                 dns_send_answer(u, service);
 196
 197                 dns_init_answer();
 198                 service_send_srv(u, s);
 199                 if (s->txt && s->txt_len)
 200                         dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len);
 201                 dns_send_answer(u, host);
 202         }
 203
 204         if (match)
 205                 return;
 206
 207         dns_init_answer();
 208         service_send_a(u);
 209         dns_send_answer(u, service_name("local"));
 210 }
 211
 212 void
 213 service_announce_services(struct uloop_fd *u, char *service)
 214 {
 215         struct service *s;
 216         int tcp = 1;
 217
 218         if (!strcmp(service, sdudp))
 219                 tcp = 0;
 220         else if (strcmp(service, sdtcp))
 221                 return;
 222
 223         avl_for_each_element(&services, s, avl) {
 224                 if (!strstr(s->service, "._tcp") && tcp)
 225                         continue;
 226                 if (!strstr(s->service, "._udp") && !tcp)
 227                         continue;
 228                 s->t = 0;
 229                 dns_init_answer();
 230                 service_send_ptr_c(u, s->service);
 231                 if (tcp)
 232                         dns_send_answer(u, sdtcp);
 233                 else
 234                         dns_send_answer(u, sdudp);
 235                 service_reply(u, s->service);
 236         }
 237 }
 238
 239 void
 240 service_announce(struct uloop_fd *u)
 241 {
 242         service_announce_services(u, sdudp);
 243         service_announce_services(u, sdtcp);
 244 }
 245
 246 static void
 247 service_load(char *path)
 248 {
 249         struct blob_attr *txt, *cur, *_tb[__SERVICE_MAX];
 250         int rem, i;
 251         glob_t gl;
 252
 253         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 254                 return;
 255
 256         for (i = 0; i < gl.gl_pathc; i++) {
 257                 blob_buf_init(&b, 0);
 258
 259                 if (!blobmsg_add_json_from_file(&b, gl.gl_pathv[i]))
 260                         continue;
 261                 blob_for_each_attr(cur, b.head, rem) {
 262                         struct service *s;
 263                         char *d_service, *d_txt, *d_daemon;
 264                         int rem2;
 265
 266                         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 267                                 _tb, blobmsg_data(cur), blobmsg_data_len(cur));
 268                         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_TXT])
 269                                 continue;
 270
 271                         s = calloc_a(sizeof(*s),
 272                                 &d_daemon, strlen(gl.gl_pathv[i]) + 1,
 273                                 &d_service, strlen(blobmsg_name(cur)) + 1,
 274                                 &d_txt, blobmsg_data_len(_tb[SERVICE_TXT]));
 275                         if (!s)
 276                                 continue;
 277
 278                         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 279                         s->service = d_service;
 280                         s->daemon = d_daemon;
 281                         strcpy(s->service, blobmsg_name(cur));
 282                         strcpy(s->daemon, gl.gl_pathv[i]);
 283                         s->avl.key = s->service;
 284                         s->active = 1;
 285                         s->t = 0;
 286                         avl_insert(&services, &s->avl);
 287
 288                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 289                                 s->txt_len += 1 + strlen(blobmsg_get_string(txt));
 290
 291                         if (!s->txt_len)
 292                                 continue;
 293
 294                         d_txt = s->txt = malloc(s->txt_len);
 295                         if (!s->txt)
 296                                 continue;
 297
 298                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 299                                 int len = strlen(blobmsg_get_string(txt));
 300                                 if (!len)
 301                                         continue;
 302                                 if (len > 0xff)
 303                                         len = 0xff;
 304                                 *d_txt = len;
 305                                 d_txt++;
 306                                 memcpy(d_txt, blobmsg_get_string(txt), len);
 307                                 d_txt += len;
 308                         }
 309                 }
 310         }
 311 }
 312
 313 void
 314 service_init(void)
 315 {
 316         if (!hostname)
 317                 hostname = get_hostname();
 318         avl_init(&services, avl_strcmp, true, NULL);
 319         service_load("/tmp/run/mdnsd/*");
 320 }
 321
 322 void
 323 service_cleanup(void)
 324 {
 325 }