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 void
 158 service_reply(struct interface *iface, const char *match, int ttl)
 159 {
 160         struct service *s;
 161
 162         vlist_for_each_element(&services, s, node) {
 163                 const char *host = service_name(s->service);
 164                 char *service = strstr(host, "._");
 165
 166                 if (!s->active || !service || !service_timeout(s))
 167                         continue;
 168
 169                 service++;
 170
 171                 if (match && strcmp(match, s->service))
 172                         continue;
 173
 174                 dns_init_answer();
 175                 service_add_ptr(service_name(s->service), ttl);
 176                 dns_send_answer(iface, service);
 177
 178                 dns_init_answer();
 179                 service_add_srv(s, ttl);
 180                 if (s->txt && s->txt_len)
 181                         dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len, ttl);
 182                 dns_send_answer(iface, host);
 183         }
 184
 185         if (match)
 186                 return;
 187
 188         service_reply_a(iface, TYPE_A, ttl);
 189 }
 190
 191 void
 192 service_announce_services(struct interface *iface, const char *service)
 193 {
 194         struct service *s;
 195         int tcp = 1;
 196
 197         if (!strcmp(service, sdudp))
 198                 tcp = 0;
 199         else if (strcmp(service, sdtcp))
 200                 return;
 201
 202         vlist_for_each_element(&services, s, node) {
 203                 if (!strstr(s->service, "._tcp") && tcp)
 204                         continue;
 205                 if (!strstr(s->service, "._udp") && !tcp)
 206                         continue;
 207                 s->t = 0;
 208                 dns_init_answer();
 209                 service_add_ptr(s->service, announce_ttl);
 210                 if (tcp)
 211                         dns_send_answer(iface, sdtcp);
 212                 else
 213                         dns_send_answer(iface, sdudp);
 214                 service_reply(iface, s->service, announce_ttl);
 215         }
 216 }
 217
 218 void
 219 service_announce(struct interface *iface)
 220 {
 221         service_announce_services(iface, sdudp);
 222         service_announce_services(iface, sdtcp);
 223 }
 224
 225 static void
 226 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 227                struct vlist_node *node_old)
 228 {
 229         struct service *s;
 230
 231         if (!node_old)
 232                 return;
 233
 234         s = container_of(node_old, struct service, node);
 235         free(s);
 236 }
 237
 238 static void
 239 service_load(char *path)
 240 {
 241         struct blob_attr *txt, *cur, *_tb[__SERVICE_MAX];
 242         int rem, i;
 243         glob_t gl;
 244
 245         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 246                 return;
 247
 248         for (i = 0; i < gl.gl_pathc; i++) {
 249                 blob_buf_init(&b, 0);
 250
 251                 if (!blobmsg_add_json_from_file(&b, gl.gl_pathv[i]))
 252                         continue;
 253                 blob_for_each_attr(cur, b.head, rem) {
 254                         struct service *s;
 255                         char *d_service, *d_daemon;
 256                         uint8_t *d_txt;
 257                         int rem2;
 258                         int txt_len = 0;
 259
 260                         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 261                                 _tb, blobmsg_data(cur), blobmsg_data_len(cur));
 262                         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_TXT])
 263                                 continue;
 264
 265                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 266                                 txt_len += 1 + strlen(blobmsg_get_string(txt));
 267
 268                         s = calloc_a(sizeof(*s),
 269                                 &d_daemon, strlen(gl.gl_pathv[i]) + 1,
 270                                 &d_service, strlen(blobmsg_name(cur)) + 1,
 271                                 &d_txt, txt_len);
 272                         if (!s)
 273                                 continue;
 274
 275                         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 276                         s->service = strcpy(d_service, blobmsg_name(cur));
 277                         s->daemon = strcpy(d_daemon, gl.gl_pathv[i]);
 278                         s->active = 1;
 279                         s->t = 0;
 280                         s->txt_len = txt_len;
 281                         s->txt = d_txt;
 282
 283                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 284                                 int len = strlen(blobmsg_get_string(txt));
 285                                 if (!len)
 286                                         continue;
 287                                 if (len > 0xff)
 288                                         len = 0xff;
 289                                 *d_txt = len;
 290                                 d_txt++;
 291                                 memcpy(d_txt, blobmsg_get_string(txt), len);
 292                                 d_txt += len;
 293                         }
 294
 295                         vlist_add(&services, &s->node, s->service);
 296                 }
 297         }
 298 }
 299
 300 void
 301 service_init(void)
 302 {
 303         get_hostname();
 304
 305         vlist_update(&services);
 306         service_load("/tmp/run/mdnsd/*");
 307         vlist_flush(&services);
 308 }
 309
 310 void
 311 service_cleanup(void)
 312 {
 313         vlist_flush(&services);
 314         blob_buf_free(&b);
 315 }