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
  37 enum {
  38         SERVICE_PORT,
  39         SERVICE_TXT,
  40         __SERVICE_MAX,
  41 };
  42
  43 struct service {
  44         struct vlist_node node;
  45
  46         time_t t;
  47
  48         const char *service;
  49         const char *daemon;
  50         const uint8_t *txt;
  51         int txt_len;
  52         int port;
  53         int active;
  54 };
  55
  56 static const struct blobmsg_policy service_policy[__SERVICE_MAX] = {
  57         [SERVICE_PORT] = { .name = "port", .type = BLOBMSG_TYPE_INT32 },
  58         [SERVICE_TXT] = { .name = "txt", .type = BLOBMSG_TYPE_ARRAY },
  59 };
  60
  61 static void
  62 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
  63                struct vlist_node *node_old);
  64
  65 static struct blob_buf b;
  66 static VLIST_TREE(services, avl_strcmp, service_update, false, false);
  67 static char *sdudp =  "_services._dns-sd._udp.local";
  68 static char *sdtcp =  "_services._dns-sd._tcp.local";
  69
  70 static const char *
  71 service_name(const char *domain)
  72 {
  73         static char buffer[256];
  74
  75         snprintf(buffer, sizeof(buffer), "%s.%s", mdns_hostname, domain);
  76
  77         return buffer;
  78 }
  79
  80 static void
  81 service_add_ptr(const char *host)
  82 {
  83         int len = dn_comp(host, mdns_buf, sizeof(mdns_buf), NULL, NULL);
  84
  85         if (len < 1)
  86                 return;
  87
  88         dns_add_answer(TYPE_PTR, mdns_buf, len);
  89 }
  90
  91 static void
  92 service_add_srv(struct service *s)
  93 {
  94         struct dns_srv_data *sd = (struct dns_srv_data *) mdns_buf;
  95         int len = sizeof(*sd);
  96
  97         len += dn_comp(mdns_hostname_local, mdns_buf + len, sizeof(mdns_buf) - len, NULL, NULL);
  98         if (len <= sizeof(*sd))
  99                 return;
 100
 101         sd->port = cpu_to_be16(s->port);
 102         dns_add_answer(TYPE_SRV, mdns_buf, len);
 103 }
 104
 105 #define TOUT_LOOKUP     60
 106
 107 static int
 108 service_timeout(struct service *s)
 109 {
 110         time_t t = time(NULL);
 111
 112         if (t - s->t <= TOUT_LOOKUP)
 113                 return 0;
 114
 115         s->t = t;
 116
 117         return 1;
 118 }
 119
 120 void
 121 service_reply_a(struct interface *iface, int type)
 122 {
 123         struct ifaddrs *ifap, *ifa;
 124         struct sockaddr_in *sa;
 125         struct sockaddr_in6 *sa6;
 126         char *addr;
 127
 128         getifaddrs(&ifap);
 129
 130         dns_init_answer();
 131         for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
 132                 if (strcmp(ifa->ifa_name, iface->name))
 133                         continue;
 134                 if (ifa->ifa_addr->sa_family==AF_INET) {
 135                         sa = (struct sockaddr_in *) ifa->ifa_addr;
 136                         addr = inet_ntoa(sa->sin_addr);
 137                         printf("Interface: %s\tAddress4: %s\n", ifa->ifa_name, addr);
 138                         dns_add_answer(TYPE_A, (uint8_t *) &sa->sin_addr, 4);
 139                 }
 140                 if (ifa->ifa_addr->sa_family==AF_INET6) {
 141                         uint8_t ll_prefix[] = {0xfe, 0x80 };
 142                         char buf[64] = { 0 };
 143                         sa6 = (struct sockaddr_in6 *) ifa->ifa_addr;
 144                         if (!memcmp(&sa6->sin6_addr, &ll_prefix, 2)) {
 145                                 if (inet_ntop(AF_INET6, &sa6->sin6_addr, buf, 64))
 146                                         printf("Interface: %s\tAddress6: %s\n", ifa->ifa_name, buf);
 147                                 dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16);
 148                         }
 149                 }
 150         }
 151         dns_send_answer(iface, mdns_hostname_local);
 152
 153         freeifaddrs(ifap);
 154 }
 155
 156 void
 157 service_reply(struct interface *iface, const char *match)
 158 {
 159         struct service *s;
 160
 161         vlist_for_each_element(&services, s, node) {
 162                 const char *host = service_name(s->service);
 163                 char *service = strstr(host, "._");
 164
 165                 if (!s->active || !service || !service_timeout(s))
 166                         continue;
 167
 168                 service++;
 169
 170                 if (match && strcmp(match, s->service))
 171                         continue;
 172
 173                 dns_init_answer();
 174                 service_add_ptr(service_name(s->service));
 175                 dns_send_answer(iface, service);
 176
 177                 dns_init_answer();
 178                 service_add_srv(s);
 179                 if (s->txt && s->txt_len)
 180                         dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len);
 181                 dns_send_answer(iface, host);
 182         }
 183
 184         if (match)
 185                 return;
 186
 187         service_reply_a(iface, TYPE_A);
 188 }
 189
 190 void
 191 service_announce_services(struct interface *iface, const char *service)
 192 {
 193         struct service *s;
 194         int tcp = 1;
 195
 196         if (!strcmp(service, sdudp))
 197                 tcp = 0;
 198         else if (strcmp(service, sdtcp))
 199                 return;
 200
 201         vlist_for_each_element(&services, s, node) {
 202                 if (!strstr(s->service, "._tcp") && tcp)
 203                         continue;
 204                 if (!strstr(s->service, "._udp") && !tcp)
 205                         continue;
 206                 s->t = 0;
 207                 dns_init_answer();
 208                 service_add_ptr(s->service);
 209                 if (tcp)
 210                         dns_send_answer(iface, sdtcp);
 211                 else
 212                         dns_send_answer(iface, sdudp);
 213                 service_reply(iface, s->service);
 214         }
 215 }
 216
 217 void
 218 service_announce(struct interface *iface)
 219 {
 220         service_announce_services(iface, sdudp);
 221         service_announce_services(iface, sdtcp);
 222 }
 223
 224 static void
 225 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 226                struct vlist_node *node_old)
 227 {
 228         struct service *s;
 229
 230         if (!node_old)
 231                 return;
 232
 233         s = container_of(node_old, struct service, node);
 234         free(s);
 235 }
 236
 237 static void
 238 service_load(char *path)
 239 {
 240         struct blob_attr *txt, *cur, *_tb[__SERVICE_MAX];
 241         int rem, i;
 242         glob_t gl;
 243
 244         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 245                 return;
 246
 247         for (i = 0; i < gl.gl_pathc; i++) {
 248                 blob_buf_init(&b, 0);
 249
 250                 if (!blobmsg_add_json_from_file(&b, gl.gl_pathv[i]))
 251                         continue;
 252                 blob_for_each_attr(cur, b.head, rem) {
 253                         struct service *s;
 254                         char *d_service, *d_daemon;
 255                         uint8_t *d_txt;
 256                         int rem2;
 257                         int txt_len = 0;
 258
 259                         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 260                                 _tb, blobmsg_data(cur), blobmsg_data_len(cur));
 261                         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_TXT])
 262                                 continue;
 263
 264                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 265                                 txt_len += 1 + strlen(blobmsg_get_string(txt));
 266
 267                         s = calloc_a(sizeof(*s),
 268                                 &d_daemon, strlen(gl.gl_pathv[i]) + 1,
 269                                 &d_service, strlen(blobmsg_name(cur)) + 1,
 270                                 &d_txt, txt_len);
 271                         if (!s)
 272                                 continue;
 273
 274                         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 275                         s->service = strcpy(d_service, blobmsg_name(cur));
 276                         s->daemon = strcpy(d_daemon, gl.gl_pathv[i]);
 277                         s->active = 1;
 278                         s->t = 0;
 279                         s->txt_len = txt_len;
 280                         s->txt = d_txt;
 281
 282                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 283                                 int len = strlen(blobmsg_get_string(txt));
 284                                 if (!len)
 285                                         continue;
 286                                 if (len > 0xff)
 287                                         len = 0xff;
 288                                 *d_txt = len;
 289                                 d_txt++;
 290                                 memcpy(d_txt, blobmsg_get_string(txt), len);
 291                                 d_txt += len;
 292                         }
 293
 294                         vlist_add(&services, &s->node, s->service);
 295                 }
 296         }
 297 }
 298
 299 void
 300 service_init(void)
 301 {
 302         get_hostname();
 303
 304         vlist_update(&services);
 305         service_load("/tmp/run/mdnsd/*");
 306         vlist_flush(&services);
 307 }
 308
 309 void
 310 service_cleanup(void)
 311 {
 312         vlist_flush(&services);
 313         blob_buf_free(&b);
 314 }