source: trunk/libtransmission/tr-udp.c @ 12543

Last change on this file since 12543 was 12543, checked in by jordan, 10 years ago

(trunk libT) #4351 "DHT can't be uninitialized during a session" -- don't process incoming DHT messages if DHT is disabled. Don't process incoming UTP messages if UTP is disabled.

File size: 9.3 KB
Line 
1/*
2Copyright (c) 2010 by Juliusz Chroboczek
3
4Permission is hereby granted, free of charge, to any person obtaining a copy
5of this software and associated documentation files (the "Software"), to deal
6in the Software without restriction, including without limitation the rights
7to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8copies of the Software, and to permit persons to whom the Software is
9furnished to do so, subject to the following conditions:
10
11The above copyright notice and this permission notice shall be included in
12all copies or substantial portions of the Software.
13
14THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
17AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20THE SOFTWARE.
21
22*/
23
24#include <assert.h>
25#include <string.h> /* memcmp(), memcpy(), memset() */
26#include <stdlib.h> /* malloc(), free() */
27
28#include <unistd.h> /* close() */
29
30#include <event2/event.h>
31
32#include "transmission.h"
33#include "net.h"
34#include "session.h"
35#include "tr-dht.h"
36#include "tr-utp.h"
37#include "tr-udp.h"
38
39/* Since we use a single UDP socket in order to implement multiple
40   uTP sockets, try to set up huge buffers. */
41
42#define RECV_BUFFER_SIZE (4 * 1024 * 1024)
43#define SEND_BUFFER_SIZE (1 * 1024 * 1024)
44#define SMALL_BUFFER_SIZE (32 * 1024)
45
46static void
47set_socket_buffers(int fd, int large)
48{
49    int size, rbuf, sbuf, rc;
50    socklen_t rbuf_len = sizeof(rbuf), sbuf_len = sizeof(sbuf);
51
52    size = large ? RECV_BUFFER_SIZE : SMALL_BUFFER_SIZE;
53    rc = setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &size, sizeof(size));
54    if(rc < 0)
55        tr_nerr("UDP", "Failed to set receive buffer: %s",
56                tr_strerror(errno));
57
58    size = large ? SEND_BUFFER_SIZE : SMALL_BUFFER_SIZE;
59    rc = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &size, sizeof(size));
60    if(rc < 0)
61        tr_nerr("UDP", "Failed to set send buffer: %s",
62                tr_strerror(errno));
63
64    if(large) {
65        rc = getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rbuf, &rbuf_len);
66        if(rc < 0)
67            rbuf = 0;
68
69        rc = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &sbuf, &sbuf_len);
70        if(rc < 0)
71            sbuf = 0;
72
73        if(rbuf < RECV_BUFFER_SIZE) {
74            tr_nerr("UDP", "Failed to set receive buffer: requested %d, got %d",
75                    RECV_BUFFER_SIZE, rbuf);
76#ifdef __linux__
77            tr_ninf("UDP",
78                    "Please add the line "
79                    "\"net.core.rmem_max = %d\" to /etc/sysctl.conf",
80                    RECV_BUFFER_SIZE);
81#endif
82        }
83
84        if(sbuf < SEND_BUFFER_SIZE) {
85            tr_nerr("UDP", "Failed to set send buffer: requested %d, got %d",
86                    SEND_BUFFER_SIZE, sbuf);
87#ifdef __linux__
88            tr_ninf("UDP",
89                    "Please add the line "
90                    "\"net.core.wmem_max = %d\" to /etc/sysctl.conf",
91                    SEND_BUFFER_SIZE);
92#endif
93        }
94    }
95}
96
97void
98tr_udpSetSocketBuffers(tr_session *session)
99{
100    bool utp = tr_sessionIsUTPEnabled(session);
101    if(session->udp_socket >= 0)
102        set_socket_buffers(session->udp_socket, utp);
103    if(session->udp6_socket >= 0)
104        set_socket_buffers(session->udp6_socket, utp);
105}
106
107
108
109
110/* BEP-32 has a rather nice explanation of why we need to bind to one
111   IPv6 address, if I may say so myself. */
112
113static void
114rebind_ipv6(tr_session *ss, bool force)
115{
116    bool is_default;
117    const struct tr_address * public_addr;
118    struct sockaddr_in6 sin6;
119    const unsigned char *ipv6 = tr_globalIPv6();
120    int s = -1, rc;
121    int one = 1;
122
123    /* We currently have no way to enable or disable IPv6 after initialisation.
124       No way to fix that without some surgery to the DHT code itself. */
125    if(ipv6 == NULL || (!force && ss->udp6_socket < 0)) {
126        if(ss->udp6_bound) {
127            free(ss->udp6_bound);
128            ss->udp6_bound = NULL;
129        }
130        return;
131    }
132
133    if(ss->udp6_bound != NULL && memcmp(ipv6, ss->udp6_bound, 16) == 0)
134        return;
135
136    s = socket(PF_INET6, SOCK_DGRAM, 0);
137    if(s < 0)
138        goto fail;
139
140#ifdef IPV6_V6ONLY
141        /* Since we always open an IPv4 socket on the same port, this
142           shouldn't matter.  But I'm superstitious. */
143        setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
144#endif
145
146    memset(&sin6, 0, sizeof(sin6));
147    sin6.sin6_family = AF_INET6;
148    if(ipv6)
149        memcpy(&sin6.sin6_addr, ipv6, 16);
150    sin6.sin6_port = htons(ss->udp_port);
151    public_addr = tr_sessionGetPublicAddress(ss, TR_AF_INET6, &is_default);
152    if(public_addr && !is_default)
153        sin6.sin6_addr = public_addr->addr.addr6;
154
155    rc = bind(s, (struct sockaddr*)&sin6, sizeof(sin6));
156    if(rc < 0)
157        goto fail;
158
159    if(ss->udp6_socket < 0) {
160        ss->udp6_socket = s;
161    } else {
162        rc = dup2(s, ss->udp6_socket);
163        if(rc < 0)
164            goto fail;
165        close(s);
166    }
167
168    if(ss->udp6_bound == NULL)
169        ss->udp6_bound = malloc(16);
170    if(ss->udp6_bound)
171        memcpy(ss->udp6_bound, ipv6, 16);
172
173    return;
174
175 fail:
176    /* Something went wrong.  It's difficult to recover, so let's simply
177       set things up so that we try again next time. */
178    tr_nerr("UDP", "Couldn't rebind IPv6 socket");
179    if(s >= 0)
180        close(s);
181    if(ss->udp6_bound) {
182        free(ss->udp6_bound);
183        ss->udp6_bound = NULL;
184    }
185}
186
187static void
188event_callback(int s, short type UNUSED, void *sv)
189{
190    int rc;
191    socklen_t fromlen;
192    unsigned char buf[4096];
193    struct sockaddr_storage from;
194    tr_session *ss = sv;
195
196    assert(tr_isSession(sv));
197    assert(type == EV_READ);
198
199    fromlen = sizeof(from);
200    rc = recvfrom(s, buf, 4096 - 1, 0,
201                  (struct sockaddr*)&from, &fromlen);
202
203    /* Since most packets we receive here are µTP, make quick inline
204       checks for the other protocols.  The logic is as follows:
205       - all DHT packets start with 'd';
206       - all UDP tracker packets start with a 32-bit (!) "action", which
207         is between 0 and 3;
208       - the above cannot be µTP packets, since these start with a 4-bit
209         version number (1). */
210    if(rc > 0) {
211        if( buf[0] == 'd' ) {
212            if( tr_sessionAllowsDHT( ss ) ) {
213                buf[rc] = '\0'; /* required by the DHT code */
214                tr_dhtCallback(buf, rc, (struct sockaddr*)&from, fromlen, sv);
215            }
216        } else if( rc >= 8 &&
217                   buf[0] == 0 && buf[1] == 0 && buf[2] == 0 && buf[3] <= 3 ) {
218            rc = tau_handle_message( ss, buf, rc );
219            if( !rc )
220                tr_ndbg("UDP", "Couldn't parse UDP tracker packet.");
221        } else {
222            if( tr_sessionIsUTPEnabled( ss ) ) {
223                rc = tr_utpPacket(buf, rc, (struct sockaddr*)&from, fromlen, ss);
224                if( !rc )
225                    tr_ndbg("UDP", "Unexpected UDP packet");
226            }
227        }
228    }
229}
230
231void
232tr_udpInit(tr_session *ss)
233{
234    bool is_default;
235    const struct tr_address * public_addr;
236    struct sockaddr_in sin;
237    int rc;
238
239    assert(ss->udp_socket < 0);
240    assert(ss->udp6_socket < 0);
241
242    ss->udp_port = tr_sessionGetPeerPort(ss);
243    if(ss->udp_port <= 0)
244        return;
245
246    ss->udp_socket = socket(PF_INET, SOCK_DGRAM, 0);
247    if(ss->udp_socket < 0) {
248        tr_nerr("UDP", "Couldn't create IPv4 socket");
249        goto ipv6;
250    }
251
252    memset(&sin, 0, sizeof(sin));
253    sin.sin_family = AF_INET;
254    public_addr = tr_sessionGetPublicAddress(ss, TR_AF_INET, &is_default);
255    if(public_addr && !is_default)
256        memcpy(&sin.sin_addr, &public_addr->addr.addr4, sizeof (struct in_addr));
257    sin.sin_port = htons(ss->udp_port);
258    rc = bind(ss->udp_socket, (struct sockaddr*)&sin, sizeof(sin));
259    if(rc < 0) {
260        tr_nerr("UDP", "Couldn't bind IPv4 socket");
261        close(ss->udp_socket);
262        ss->udp_socket = -1;
263        goto ipv6;
264    }
265    ss->udp_event =
266        event_new(ss->event_base, ss->udp_socket, EV_READ | EV_PERSIST,
267                  event_callback, ss);
268    if( ss->udp_event == NULL )
269        tr_nerr("UDP", "Couldn't allocate IPv4 event");
270
271 ipv6:
272    if(tr_globalIPv6())
273        rebind_ipv6(ss, true);
274    if(ss->udp6_socket >= 0) {
275        ss->udp6_event =
276            event_new(ss->event_base, ss->udp6_socket, EV_READ | EV_PERSIST,
277                      event_callback, ss);
278        if(ss->udp6_event == NULL)
279            tr_nerr("UDP", "Couldn't allocate IPv6 event");
280    }
281
282    tr_udpSetSocketBuffers(ss);
283
284    if(ss->isDHTEnabled)
285        tr_dhtInit(ss);
286
287    if(ss->udp_event)
288        event_add(ss->udp_event, NULL);
289    if(ss->udp6_event)
290        event_add(ss->udp6_event, NULL);
291}
292
293void
294tr_udpUninit(tr_session *ss)
295{
296    tr_dhtUninit(ss);
297
298    if(ss->udp_socket >= 0) {
299        tr_netCloseSocket( ss->udp_socket );
300        ss->udp_socket = -1;
301    }
302
303    if(ss->udp_event) {
304        event_free(ss->udp_event);
305        ss->udp_event = NULL;
306    }
307
308    if(ss->udp6_socket >= 0) {
309        tr_netCloseSocket( ss->udp6_socket );
310        ss->udp6_socket = -1;
311    }
312
313    if(ss->udp6_event) {
314        event_free(ss->udp6_event);
315        ss->udp6_event = NULL;
316    }
317
318    if(ss->udp6_bound) {
319        free(ss->udp6_bound);
320        ss->udp6_bound = NULL;
321    }
322}
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