source: trunk/libtransmission/tr-udp.c @ 12274

Last change on this file since 12274 was 12274, checked in by jordan, 11 years ago

(trunk libT) fix minor dead store detected by clang static analyzer

File size: 8.7 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    tr_session *ss = sv;
191    unsigned char *buf;
192    struct sockaddr_storage from;
193    socklen_t fromlen;
194    int rc;
195
196    assert(tr_isSession(sv));
197    assert(type == EV_READ);
198
199    buf = malloc(4096);
200    if(buf == NULL) {
201        tr_nerr("UDP", "Couldn't allocate buffer");
202        return;
203    }
204
205    fromlen = sizeof(from);
206    rc = recvfrom(s, buf, 4096 - 1, 0,
207                  (struct sockaddr*)&from, &fromlen);
208    if(rc > 0) {
209        if( tau_handle_message( ss, buf, rc ) ) {
210            tr_ndbg("UDP", "Received UDP Tracker packet");
211        }
212        else if( buf[0] == 'd' ) {
213            /* DHT packet. */
214            buf[rc] = '\0';
215            tr_dhtCallback(buf, rc, (struct sockaddr*)&from, fromlen, sv);
216        } else {
217            rc = tr_utpPacket(buf, rc, (struct sockaddr*)&from, fromlen, ss);
218            if(!rc)
219                tr_ndbg("UDP", "Unexpected UDP packet");
220        }
221    }
222
223    free(buf);
224}
225
226void
227tr_udpInit(tr_session *ss)
228{
229    bool is_default;
230    const struct tr_address * public_addr;
231    struct sockaddr_in sin;
232    int rc;
233
234    assert(ss->udp_socket < 0);
235    assert(ss->udp6_socket < 0);
236
237    ss->udp_port = tr_sessionGetPeerPort(ss);
238    if(ss->udp_port <= 0)
239        return;
240
241    ss->udp_socket = socket(PF_INET, SOCK_DGRAM, 0);
242    if(ss->udp_socket < 0) {
243        tr_nerr("UDP", "Couldn't create IPv4 socket");
244        goto ipv6;
245    }
246
247    memset(&sin, 0, sizeof(sin));
248    sin.sin_family = AF_INET;
249    public_addr = tr_sessionGetPublicAddress(ss, TR_AF_INET, &is_default);
250    if(public_addr && !is_default)
251        memcpy(&sin.sin_addr, &public_addr->addr.addr4, sizeof (struct in_addr));
252    sin.sin_port = htons(ss->udp_port);
253    rc = bind(ss->udp_socket, (struct sockaddr*)&sin, sizeof(sin));
254    if(rc < 0) {
255        tr_nerr("UDP", "Couldn't bind IPv4 socket");
256        close(ss->udp_socket);
257        ss->udp_socket = -1;
258        goto ipv6;
259    }
260    ss->udp_event =
261        event_new(ss->event_base, ss->udp_socket, EV_READ | EV_PERSIST,
262                  event_callback, ss);
263    if( ss->udp_event == NULL )
264        tr_nerr("UDP", "Couldn't allocate IPv4 event");
265
266 ipv6:
267    if(tr_globalIPv6())
268        rebind_ipv6(ss, true);
269    if(ss->udp6_socket >= 0) {
270        ss->udp6_event =
271            event_new(ss->event_base, ss->udp6_socket, EV_READ | EV_PERSIST,
272                      event_callback, ss);
273        if(ss->udp6_event == NULL)
274            tr_nerr("UDP", "Couldn't allocate IPv6 event");
275    }
276
277    tr_udpSetSocketBuffers(ss);
278
279    if(ss->isDHTEnabled)
280        tr_dhtInit(ss);
281
282    if(ss->udp_event)
283        event_add(ss->udp_event, NULL);
284    if(ss->udp6_event)
285        event_add(ss->udp6_event, NULL);
286}
287
288void
289tr_udpUninit(tr_session *ss)
290{
291    if(ss->udp_socket >= 0) {
292        tr_netCloseSocket( ss->udp_socket );
293        ss->udp_socket = -1;
294    }
295
296    if(ss->udp_event) {
297        event_free(ss->udp_event);
298        ss->udp_event = NULL;
299    }
300
301    if(ss->udp6_socket >= 0) {
302        tr_netCloseSocket( ss->udp6_socket );
303        ss->udp6_socket = -1;
304    }
305
306    if(ss->udp6_event) {
307        event_free(ss->udp6_event);
308        ss->udp6_event = NULL;
309    }
310
311    if(ss->udp6_bound) {
312        free(ss->udp6_bound);
313        ss->udp6_bound = NULL;
314    }
315}
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