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 <arpa/nameser.h>
  16 #include <sys/socket.h>
  17
  18 #include <ifaddrs.h>
  19 #include <resolv.h>
  20 #include <glob.h>
  21 #include <stdio.h>
  22 #include <time.h>
  23
  24 #include <uci.h>
  25 #include <uci_blob.h>
  26
  27 #include <libubox/vlist.h>
  28 #include <libubox/uloop.h>
  29 #include <libubox/avl-cmp.h>
  30 #include <libubox/blobmsg_json.h>
  31
  32 #include "dns.h"
  33 #include "service.h"
  34 #include "util.h"
  35 #include "interface.h"
  36 #include "announce.h"
  37
  38 enum {
  39         SERVICE_PORT,
  40         SERVICE_TXT,
  41         __SERVICE_MAX,
  42 };
  43
  44 struct service {
  45         struct vlist_node node;
  46
  47         time_t t;
  48
  49         const char *service;
  50         const char *daemon;
  51         const uint8_t *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 void
  63 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
  64                struct vlist_node *node_old);
  65
  66 static struct blob_buf b;
  67 static VLIST_TREE(services, avl_strcmp, service_update, false, false);
  68 static char *sdudp =  "_services._dns-sd._udp.local";
  69 static char *sdtcp =  "_services._dns-sd._tcp.local";
  70
  71 static const char *
  72 service_name(const char *domain)
  73 {
  74         static char buffer[256];
  75
  76         snprintf(buffer, sizeof(buffer), "%s.%s", mdns_hostname, domain);
  77
  78         return buffer;
  79 }
  80
  81 static void
  82 service_add_ptr(const char *host, int ttl)
  83 {
  84         int len = dn_comp(host, mdns_buf, sizeof(mdns_buf), NULL, NULL);
  85
  86         if (len < 1)
  87                 return;
  88
  89         dns_add_answer(TYPE_PTR, mdns_buf, len, ttl);
  90 }
  91
  92 static void
  93 service_add_srv(struct service *s, int ttl)
  94 {
  95         struct dns_srv_data *sd = (struct dns_srv_data *) mdns_buf;
  96         int len = sizeof(*sd);
  97
  98         len += dn_comp(mdns_hostname_local, mdns_buf + len, sizeof(mdns_buf) - len, NULL, NULL);
  99         if (len <= sizeof(*sd))
 100                 return;
 101
 102         sd->port = cpu_to_be16(s->port);
 103         dns_add_answer(TYPE_SRV, mdns_buf, len, ttl);
 104 }
 105
 106 #define TOUT_LOOKUP     60
 107
 108 static int
 109 service_timeout(struct service *s)
 110 {
 111         time_t t = time(NULL);
 112
 113         if (t - s->t <= TOUT_LOOKUP)
 114                 return 0;
 115
 116         s->t = t;
 117
 118         return 1;
 119 }
 120
 121 void
 122 service_reply_a(struct interface *iface, int type, int ttl)
 123 {
 124         struct ifaddrs *ifap, *ifa;
 125         struct sockaddr_in *sa;
 126         struct sockaddr_in6 *sa6;
 127         char *addr;
 128
 129         getifaddrs(&ifap);
 130
 131         dns_init_answer();
 132         for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
 133                 if (strcmp(ifa->ifa_name, iface->name))
 134                         continue;
 135                 if (ifa->ifa_addr->sa_family==AF_INET) {
 136                         sa = (struct sockaddr_in *) ifa->ifa_addr;
 137                         addr = inet_ntoa(sa->sin_addr);
 138                         printf("Interface: %s\tAddress4: %s\n", ifa->ifa_name, addr);
 139                         dns_add_answer(TYPE_A, (uint8_t *) &sa->sin_addr, 4, ttl);
 140                 }
 141                 if (ifa->ifa_addr->sa_family==AF_INET6) {
 142                         uint8_t ll_prefix[] = {0xfe, 0x80 };
 143                         char buf[64] = { 0 };
 144                         sa6 = (struct sockaddr_in6 *) ifa->ifa_addr;
 145                         if (!memcmp(&sa6->sin6_addr, &ll_prefix, 2)) {
 146                                 if (inet_ntop(AF_INET6, &sa6->sin6_addr, buf, 64))
 147                                         printf("Interface: %s\tAddress6: %s\n", ifa->ifa_name, buf);
 148                                 dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16, ttl);
 149                         }
 150                 }
 151         }
 152         dns_send_answer(iface, mdns_hostname_local);
 153
 154         freeifaddrs(ifap);
 155 }
 156
 157 static void
 158 service_reply_single(struct interface *iface, struct service *s, const char *match, int ttl)
 159 {
 160         const char *host = service_name(s->service);
 161         char *service = strstr(host, "._");
 162
 163         if (!s->active || !service || !service_timeout(s))
 164                 return;
 165
 166         service++;
 167
 168         if (match && strcmp(match, s->service))
 169                 return;
 170
 171         dns_init_answer();
 172         service_add_ptr(service_name(s->service), ttl);
 173         dns_send_answer(iface, service);
 174
 175         dns_init_answer();
 176         service_add_srv(s, ttl);
 177         if (s->txt && s->txt_len)
 178                 dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len, ttl);
 179         dns_send_answer(iface, host);
 180 }
 181
 182 void
 183 service_reply(struct interface *iface, const char *match, int ttl)
 184 {
 185         struct service *s;
 186
 187         vlist_for_each_element(&services, s, node)
 188                 service_reply_single(iface, s, match, ttl);
 189
 190         if (match)
 191                 return;
 192
 193         service_reply_a(iface, TYPE_A, ttl);
 194 }
 195
 196 void
 197 service_announce_services(struct interface *iface, const char *service)
 198 {
 199         struct service *s;
 200         int tcp = 1;
 201
 202         if (!strcmp(service, sdudp))
 203                 tcp = 0;
 204         else if (strcmp(service, sdtcp))
 205                 return;
 206
 207         vlist_for_each_element(&services, s, node) {
 208                 if (!strstr(s->service, "._tcp") && tcp)
 209                         continue;
 210                 if (!strstr(s->service, "._udp") && !tcp)
 211                         continue;
 212                 s->t = 0;
 213                 dns_init_answer();
 214                 service_add_ptr(s->service, announce_ttl);
 215                 if (tcp)
 216                         dns_send_answer(iface, sdtcp);
 217                 else
 218                         dns_send_answer(iface, sdudp);
 219                 service_reply(iface, s->service, announce_ttl);
 220         }
 221 }
 222
 223 void
 224 service_announce(struct interface *iface)
 225 {
 226         service_announce_services(iface, sdudp);
 227         service_announce_services(iface, sdtcp);
 228 }
 229
 230 static void
 231 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 232                struct vlist_node *node_old)
 233 {
 234         struct interface *iface;
 235         struct service *s;
 236
 237         if (!node_old)
 238                 return;
 239
 240         s = container_of(node_old, struct service, node);
 241
 242         if (!node_new)
 243                 vlist_for_each_element(&interfaces, iface, node)
 244                         service_reply_single(iface, s, NULL, 0);
 245
 246         free(s);
 247 }
 248
 249 static void
 250 service_load(char *path)
 251 {
 252         struct blob_attr *txt, *cur, *_tb[__SERVICE_MAX];
 253         int rem, i;
 254         glob_t gl;
 255
 256         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 257                 return;
 258
 259         for (i = 0; i < gl.gl_pathc; i++) {
 260                 blob_buf_init(&b, 0);
 261
 262                 if (!blobmsg_add_json_from_file(&b, gl.gl_pathv[i]))
 263                         continue;
 264                 blob_for_each_attr(cur, b.head, rem) {
 265                         struct service *s;
 266                         char *d_service, *d_daemon;
 267                         uint8_t *d_txt;
 268                         int rem2;
 269                         int txt_len = 0;
 270
 271                         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 272                                 _tb, blobmsg_data(cur), blobmsg_data_len(cur));
 273                         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_TXT])
 274                                 continue;
 275
 276                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 277                                 txt_len += 1 + strlen(blobmsg_get_string(txt));
 278
 279                         s = calloc_a(sizeof(*s),
 280                                 &d_daemon, strlen(gl.gl_pathv[i]) + 1,
 281                                 &d_service, strlen(blobmsg_name(cur)) + 1,
 282                                 &d_txt, txt_len);
 283                         if (!s)
 284                                 continue;
 285
 286                         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 287                         s->service = strcpy(d_service, blobmsg_name(cur));
 288                         s->daemon = strcpy(d_daemon, gl.gl_pathv[i]);
 289                         s->active = 1;
 290                         s->t = 0;
 291                         s->txt_len = txt_len;
 292                         s->txt = d_txt;
 293
 294                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 295                                 int len = strlen(blobmsg_get_string(txt));
 296                                 if (!len)
 297                                         continue;
 298                                 if (len > 0xff)
 299                                         len = 0xff;
 300                                 *d_txt = len;
 301                                 d_txt++;
 302                                 memcpy(d_txt, blobmsg_get_string(txt), len);
 303                                 d_txt += len;
 304                         }
 305
 306                         vlist_add(&services, &s->node, s->service);
 307                 }
 308         }
 309 }
 310
 311 void
 312 service_init(void)
 313 {
 314         get_hostname();
 315
 316         vlist_update(&services);
 317         service_load("/tmp/run/mdnsd/*");
 318         vlist_flush(&services);
 319 }
 320
 321 void
 322 service_cleanup(void)
 323 {
 324         vlist_flush(&services);
 325         blob_buf_free(&b);
 326 }