simple-protocol.c revision 66142b071a2497d7e3cf58d7bf5159bb1c970d84 
1/* $Id$ */
2
3/***
4  This file is part of avahi.
5
6  avahi is free software; you can redistribute it and/or modify it
7  under the terms of the GNU Lesser General Public License as
8  published by the Free Software Foundation; either version 2.1 of the
9  License, or (at your option) any later version.
10
11  avahi is distributed in the hope that it will be useful, but WITHOUT
12  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
14  Public License for more details.
15
16  You should have received a copy of the GNU Lesser General Public
17  License along with avahi; if not, write to the Free Software
18  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
19  USA.
20***/
21
22#ifdef HAVE_CONFIG_H
23#include <config.h>
24#endif
25
26#include <string.h>
27#include <sys/socket.h>
28#include <stdio.h>
29#include <unistd.h>
30#include <sys/un.h>
31#include <errno.h>
32#include <fcntl.h>
33
34#include <glib.h>
35
36#include <avahi-core/llist.h>
37#include <avahi-core/log.h>
38
39#include "simple-protocol.h"
40#include "main.h"
41
42#define BUFFER_SIZE (20*1024)
43
44#define CLIENTS_MAX 50
45
46typedef struct Client Client;
47typedef struct Server Server;
48
49typedef enum {
50    CLIENT_IDLE,
51    CLIENT_RESOLVE_HOSTNAME,
52    CLIENT_RESOLVE_ADDRESS,
53    CLIENT_BROWSE_DNS_SERVERS,
54    CLIENT_DEAD
55} ClientState;
56
57struct Client {
58    Server *server;
59
60    ClientState state;
61
62    gint fd;
63    GPollFD poll_fd;
64
65    gchar inbuf[BUFFER_SIZE], outbuf[BUFFER_SIZE];
66    guint inbuf_length, outbuf_length;
67
68    AvahiHostNameResolver *host_name_resolver;
69    AvahiAddressResolver *address_resolver;
70    AvahiDNSServerBrowser *dns_server_browser;
71
72    AvahiProtocol afquery;
73
74    AVAHI_LLIST_FIELDS(Client, clients);
75};
76
77struct Server {
78    GSource source;
79    GMainContext *context;
80    GPollFD poll_fd;
81    gint fd;
82    AVAHI_LLIST_HEAD(Client, clients);
83
84    guint n_clients;
85    gboolean bind_successful;
86};
87
88static Server *server = NULL;
89
90static void client_free(Client *c) {
91    g_assert(c);
92
93    g_assert(c->server->n_clients >= 1);
94    c->server->n_clients--;
95
96    if (c->host_name_resolver)
97        avahi_host_name_resolver_free(c->host_name_resolver);
98
99    if (c->address_resolver)
100        avahi_address_resolver_free(c->address_resolver);
101
102    if (c->dns_server_browser)
103        avahi_dns_server_browser_free(c->dns_server_browser);
104
105    g_source_remove_poll(&c->server->source, &c->poll_fd);
106    close(c->fd);
107    AVAHI_LLIST_REMOVE(Client, clients, c->server->clients, c);
108    g_free(c);
109}
110
111static void client_new(Server *s, int fd) {
112    Client *c;
113
114    g_assert(fd >= 0);
115
116    c = g_new(Client, 1);
117    c->server = s;
118    c->fd = fd;
119    c->state = CLIENT_IDLE;
120
121    c->inbuf_length = c->outbuf_length = 0;
122
123    c->host_name_resolver = NULL;
124    c->address_resolver = NULL;
125    c->dns_server_browser = NULL;
126
127    memset(&c->poll_fd, 0, sizeof(GPollFD));
128    c->poll_fd.fd = fd;
129    c->poll_fd.events = G_IO_IN|G_IO_ERR|G_IO_HUP;
130    g_source_add_poll(&s->source, &c->poll_fd);
131
132    AVAHI_LLIST_PREPEND(Client, clients, s->clients, c);
133    s->n_clients++;
134}
135
136static void client_output(Client *c, const guint8*data, guint size) {
137    guint k, m;
138
139    g_assert(c);
140    g_assert(data);
141
142    if (!size)
143        return;
144
145    k = sizeof(c->outbuf) - c->outbuf_length;
146    m = size > k ? k : size;
147
148    memcpy(c->outbuf + c->outbuf_length, data, m);
149    c->outbuf_length += m;
150
151    c->poll_fd.events |= G_IO_OUT;
152}
153
154static void client_output_printf(Client *c, const gchar *format, ...) {
155    gchar *t;
156    va_list ap;
157
158    va_start(ap, format);
159    t = g_strdup_vprintf(format, ap);
160    va_end(ap);
161
162    client_output(c, (guint8*) t, strlen(t));
163    g_free(t);
164}
165
166
167static void host_name_resolver_callback(AvahiHostNameResolver *r, gint iface, guchar protocol, AvahiBrowserEvent event, const gchar *hostname, const AvahiAddress *a, gpointer userdata) {
168    Client *c = userdata;
169
170    g_assert(c);
171
172
173    if (event == AVAHI_RESOLVER_TIMEOUT)
174        client_output_printf(c, "- Query timed out\n");
175    else {
176        gchar t[64];
177        avahi_address_snprint(t, sizeof(t), a);
178        client_output_printf(c, "+ %i %u %s %s\n", iface, protocol, hostname, t);
179    }
180
181    c->state = CLIENT_DEAD;
182}
183
184static void address_resolver_callback(AvahiAddressResolver *r, gint iface, guchar protocol, AvahiBrowserEvent event, const AvahiAddress *a, const gchar *hostname, gpointer userdata) {
185    Client *c = userdata;
186
187
188    g_assert(c);
189
190    if (event == AVAHI_RESOLVER_TIMEOUT)
191        client_output_printf(c, "- Query timed out\n");
192    else
193        client_output_printf(c, "+ %i %u %s\n", iface, protocol, hostname);
194
195    c->state = CLIENT_DEAD;
196}
197
198static void dns_server_browser_callback(AvahiDNSServerBrowser *b, gint interface, guchar protocol, AvahiBrowserEvent event, const gchar *host_name, const AvahiAddress *a, guint16 port, gpointer userdata) {
199    Client *c = userdata;
200    gchar t[64];
201
202    g_assert(c);
203
204    if (!a)
205        return;
206
207    avahi_address_snprint(t, sizeof(t), a);
208    client_output_printf(c, "%c %i %u %s %u\n", event == AVAHI_BROWSER_NEW ? '>' : '<',  interface, protocol, t, port);
209}
210
211static void handle_line(Client *c, const gchar *s) {
212    gchar cmd[64], arg[64];
213    gint n_args;
214
215    g_assert(c);
216    g_assert(s);
217
218    if (c->state != CLIENT_IDLE)
219        return;
220
221    if ((n_args = sscanf(s, "%63s %63s", cmd, arg)) < 1 ) {
222        client_output_printf(c, "- Failed to parse command, try \"HELP\".\n");
223        c->state = CLIENT_DEAD;
224        return;
225    }
226
227    if (strcmp(cmd, "HELP") == 0) {
228        client_output_printf(c,
229                             "+ Available commands are:\n"
230                             "+      RESOLVE-HOSTNAME <hostname>\n"
231                             "+      RESOLVE-HOSTNAME-IPV6 <hostname>\n"
232                             "+      RESOLVE-HOSTNAME-IPV4 <hostname>\n"
233                             "+      RESOLVE-ADDRESS <address>\n"
234                             "+      BROWSE-DNS-SERVERS\n"
235                             "+      BROWSE-DNS-SERVERS-IPV4\n"
236                             "+      BROWSE-DNS-SERVERS-IPV6\n");
237        c->state = CLIENT_DEAD; }
238    else if (strcmp(cmd, "FUCK") == 0 && n_args == 1) {
239        client_output_printf(c, "FUCK: Go fuck yourself!\n");
240        c->state = CLIENT_DEAD;
241    } else if (strcmp(cmd, "RESOLVE-HOSTNAME-IPV4") == 0 && n_args == 2) {
242        c->state = CLIENT_RESOLVE_HOSTNAME;
243        c->host_name_resolver = avahi_host_name_resolver_new(avahi_server, -1, AF_UNSPEC, arg, c->afquery = AF_INET, host_name_resolver_callback, c);
244    } else if (strcmp(cmd, "RESOLVE-HOSTNAME-IPV6") == 0 && n_args == 2) {
245        c->state = CLIENT_RESOLVE_HOSTNAME;
246        c->host_name_resolver = avahi_host_name_resolver_new(avahi_server, -1, AF_UNSPEC, arg, c->afquery = AF_INET6, host_name_resolver_callback, c);
247    } else if (strcmp(cmd, "RESOLVE-HOSTNAME") == 0 && n_args == 2) {
248        c->state = CLIENT_RESOLVE_HOSTNAME;
249        c->host_name_resolver = avahi_host_name_resolver_new(avahi_server, -1, AF_UNSPEC, arg, c->afquery = AF_UNSPEC, host_name_resolver_callback, c);
250    } else if (strcmp(cmd, "RESOLVE-ADDRESS") == 0 && n_args == 2) {
251        AvahiAddress addr;
252
253        if (!(avahi_address_parse(arg, AF_UNSPEC, &addr))) {
254            client_output_printf(c, "- Failed to parse address \"%s\".\n", arg);
255            c->state = CLIENT_DEAD;
256        } else {
257            c->state = CLIENT_RESOLVE_ADDRESS;
258            c->address_resolver = avahi_address_resolver_new(avahi_server, -1, AF_UNSPEC, &addr, address_resolver_callback, c);
259        }
260    } else if (strcmp(cmd, "BROWSE-DNS-SERVERS-IPV4") == 0 && n_args == 1) {
261        c->state = CLIENT_BROWSE_DNS_SERVERS;
262        c->dns_server_browser = avahi_dns_server_browser_new(avahi_server, -1, AF_UNSPEC, NULL, AVAHI_DNS_SERVER_RESOLVE, c->afquery = AF_INET, dns_server_browser_callback, c);
263        client_output_printf(c, "+ Browsing ...\n");
264    } else if (strcmp(cmd, "BROWSE-DNS-SERVERS-IPV6") == 0 && n_args == 1) {
265        c->state = CLIENT_BROWSE_DNS_SERVERS;
266        c->dns_server_browser = avahi_dns_server_browser_new(avahi_server, -1, AF_UNSPEC, NULL, AVAHI_DNS_SERVER_RESOLVE, c->afquery = AF_INET6, dns_server_browser_callback, c);
267        client_output_printf(c, "+ Browsing ...\n");
268    } else if (strcmp(cmd, "BROWSE-DNS-SERVERS") == 0 && n_args == 1) {
269        c->state = CLIENT_BROWSE_DNS_SERVERS;
270        c->dns_server_browser = avahi_dns_server_browser_new(avahi_server, -1, AF_UNSPEC, NULL, AVAHI_DNS_SERVER_RESOLVE, c->afquery = AF_UNSPEC, dns_server_browser_callback, c);
271        client_output_printf(c, "+ Browsing ...\n");
272    } else {
273        client_output_printf(c, "- Invalid command \"%s\", try \"HELP\".\n", cmd);
274        c->state = CLIENT_DEAD;
275    }
276}
277
278static void handle_input(Client *c) {
279    g_assert(c);
280
281    for (;;) {
282        gchar *e;
283        guint k;
284
285        if (!(e = memchr(c->inbuf, '\n', c->inbuf_length)))
286            break;
287
288        k = e - (gchar*) c->inbuf;
289        *e = 0;
290
291        handle_line(c, c->inbuf);
292        c->inbuf_length -= k + 1;
293        memmove(c->inbuf, e+1, c->inbuf_length);
294    }
295}
296
297static void client_work(Client *c) {
298    g_assert(c);
299
300    if ((c->poll_fd.revents & G_IO_IN) && c->inbuf_length < sizeof(c->inbuf)) {
301        ssize_t r;
302
303        if ((r = read(c->fd, c->inbuf + c->inbuf_length, sizeof(c->inbuf) - c->inbuf_length)) <= 0) {
304            if (r < 0)
305                avahi_log_warn("read(): %s", strerror(errno));
306            client_free(c);
307            return;
308        }
309
310        c->inbuf_length += r;
311        g_assert(c->inbuf_length <= sizeof(c->inbuf));
312
313        handle_input(c);
314    }
315
316    if ((c->poll_fd.revents & G_IO_OUT) && c->outbuf_length > 0) {
317        ssize_t r;
318
319        if ((r = write(c->fd, c->outbuf, c->outbuf_length)) < 0) {
320            avahi_log_warn("write(): %s", strerror(errno));
321            client_free(c);
322            return;
323        }
324
325        g_assert((guint) r <= c->outbuf_length);
326        c->outbuf_length -= r;
327
328        if (c->outbuf_length)
329            memmove(c->outbuf, c->outbuf + r, c->outbuf_length - r);
330
331        if (c->outbuf_length == 0 && c->state == CLIENT_DEAD) {
332            client_free(c);
333            return;
334        }
335    }
336
337    c->poll_fd.events =
338        G_IO_ERR |
339        G_IO_HUP |
340        (c->outbuf_length > 0 ? G_IO_OUT : 0) |
341        (c->inbuf_length < sizeof(c->inbuf) ? G_IO_IN : 0);
342}
343
344static gboolean prepare_func(GSource *source, gint *timeout) {
345    g_assert(source);
346    g_assert(timeout);
347
348    *timeout = -1;
349    return FALSE;
350}
351
352static gboolean check_func(GSource *source) {
353    Server *s = (Server*) source;
354    Client *c;
355
356    g_assert(s);
357
358    if (s->poll_fd.revents)
359        return TRUE;
360
361    for (c = s->clients; c; c = c->clients_next)
362        if (c->poll_fd.revents)
363            return TRUE;
364
365    return FALSE;
366}
367
368static gboolean dispatch_func(GSource *source, GSourceFunc callback, gpointer user_data) {
369    Server *s = (Server*) source;
370    Client *c, *n;
371
372    g_assert(s);
373
374    if (s->poll_fd.revents & G_IO_IN) {
375        gint fd;
376
377        if ((fd = accept(s->fd, NULL, NULL)) < 0)
378            avahi_log_warn("accept(): %s", strerror(errno));
379        else
380            client_new(s, fd);
381    } else if (s->poll_fd.revents)
382        g_error("Invalid revents");
383
384    for (c = s->clients; c; c = n) {
385        n = c->clients_next;
386        if (c->poll_fd.revents)
387            client_work(c);
388    }
389
390    return TRUE;
391}
392
393int simple_protocol_setup(GMainContext *c) {
394    struct sockaddr_un sa;
395    mode_t u;
396
397    static GSourceFuncs source_funcs = {
398        prepare_func,
399        check_func,
400        dispatch_func,
401        NULL,
402        NULL,
403        NULL
404    };
405
406    g_assert(!server);
407
408    server = (Server*) g_source_new(&source_funcs, sizeof(Server));
409    server->bind_successful = FALSE;
410    server->fd = -1;
411    AVAHI_LLIST_HEAD_INIT(Client, server->clients);
412    g_main_context_ref(server->context = (c ? c : g_main_context_default()));
413    server->clients = NULL;
414
415    u = umask(0000);
416
417    if ((server->fd = socket(PF_LOCAL, SOCK_STREAM, 0)) < 0) {
418        avahi_log_warn("socket(PF_LOCAL, SOCK_STREAM, 0): %s", strerror(errno));
419        goto fail;
420    }
421
422    memset(&sa, 0, sizeof(sa));
423    sa.sun_family = AF_LOCAL;
424    strncpy(sa.sun_path, AVAHI_SOCKET, sizeof(sa.sun_path)-1);
425
426    /* We simply remove existing UNIX sockets under this name. The
427       Avahi daemons makes sure that it runs only once on a host,
428       therefore sockets that already exist are stale and may be
429       removed without any ill effects */
430
431    unlink(AVAHI_SOCKET);
432
433    if (bind(server->fd, &sa, sizeof(sa)) < 0) {
434        avahi_log_warn("bind(): %s", strerror(errno));
435        goto fail;
436    }
437
438    server->bind_successful = TRUE;
439
440    if (listen(server->fd, 2) < 0) {
441        avahi_log_warn("listen(): %s", strerror(errno));
442        goto fail;
443    }
444
445    umask(u);
446
447    memset(&server->poll_fd, 0, sizeof(GPollFD));
448    server->poll_fd.fd = server->fd;
449    server->poll_fd.events = G_IO_IN|G_IO_ERR;
450    g_source_add_poll(&server->source, &server->poll_fd);
451
452    g_source_attach(&server->source, server->context);
453
454    return 0;
455
456fail:
457
458    umask(u);
459    simple_protocol_shutdown();
460
461    return -1;
462}
463
464void simple_protocol_shutdown(void) {
465
466    if (server) {
467
468        while (server->clients)
469            client_free(server->clients);
470
471        if (server->bind_successful)
472            unlink(AVAHI_SOCKET);
473
474        if (server->fd >= 0)
475            close(server->fd);
476
477        g_main_context_unref(server->context);
478
479        g_source_destroy(&server->source);
480        g_source_unref(&server->source);
481
482        server = NULL;
483    }
484}
485
486void simple_protocol_restart_queries(void) {
487    Client *c;
488
489    /* Restart queries in case of local domain name changes */
490
491    g_assert(server);
492
493    for (c = server->clients; c; c = c->clients_next)
494        if (c->state == CLIENT_BROWSE_DNS_SERVERS && c->dns_server_browser) {
495            avahi_dns_server_browser_free(c->dns_server_browser);
496            c->dns_server_browser = avahi_dns_server_browser_new(avahi_server, -1, AF_UNSPEC, NULL, AVAHI_DNS_SERVER_RESOLVE, c->afquery, dns_server_browser_callback, c);
497        }
498}
499
500
501