blob: 882c5c4de69e69ef390f73059fba96b3cad23799 [file] [log] [blame]
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
2 * net/dccp/ipv4.c
3 *
4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070013#include <linux/dccp.h>
14#include <linux/icmp.h>
15#include <linux/module.h>
16#include <linux/skbuff.h>
17#include <linux/random.h>
18
19#include <net/icmp.h>
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -080020#include <net/inet_common.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070021#include <net/inet_hashtables.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020022#include <net/inet_sock.h>
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -080023#include <net/protocol.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070024#include <net/sock.h>
Arnaldo Carvalho de Melo6d6ee432005-12-13 23:25:19 -080025#include <net/timewait_sock.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070026#include <net/tcp_states.h>
27#include <net/xfrm.h>
28
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070029#include "ackvec.h"
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070030#include "ccid.h"
31#include "dccp.h"
Andrea Bittauafe00252006-03-20 17:43:56 -080032#include "feat.h"
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070033
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -080034/*
Pavel Emelyanov13f51d82008-04-14 02:38:45 -070035 * The per-net dccp.v4_ctl_sk socket is used for responding to
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -080036 * the Out-of-the-blue (OOTB) packets. A control sock will be created
37 * for this socket at the initialization time.
38 */
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -080039
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -080040int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070041{
42 struct inet_sock *inet = inet_sk(sk);
43 struct dccp_sock *dp = dccp_sk(sk);
44 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
45 struct rtable *rt;
Al Virobada8ad2006-09-26 21:27:15 -070046 __be32 daddr, nexthop;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070047 int tmp;
48 int err;
49
50 dp->dccps_role = DCCP_ROLE_CLIENT;
51
52 if (addr_len < sizeof(struct sockaddr_in))
53 return -EINVAL;
54
55 if (usin->sin_family != AF_INET)
56 return -EAFNOSUPPORT;
57
58 nexthop = daddr = usin->sin_addr.s_addr;
59 if (inet->opt != NULL && inet->opt->srr) {
60 if (daddr == 0)
61 return -EINVAL;
62 nexthop = inet->opt->faddr;
63 }
64
65 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
66 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
67 IPPROTO_DCCP,
David S. Miller8eb90862007-02-08 02:09:21 -080068 inet->sport, usin->sin_port, sk, 1);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070069 if (tmp < 0)
70 return tmp;
71
72 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
73 ip_rt_put(rt);
74 return -ENETUNREACH;
75 }
76
77 if (inet->opt == NULL || !inet->opt->srr)
78 daddr = rt->rt_dst;
79
80 if (inet->saddr == 0)
81 inet->saddr = rt->rt_src;
82 inet->rcv_saddr = inet->saddr;
83
84 inet->dport = usin->sin_port;
85 inet->daddr = daddr;
86
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -080087 inet_csk(sk)->icsk_ext_hdr_len = 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070088 if (inet->opt != NULL)
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -080089 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070090 /*
91 * Socket identity is still unknown (sport may be zero).
92 * However we set state to DCCP_REQUESTING and not releasing socket
93 * lock select source port, enter ourselves into the hash tables and
94 * complete initialization after this.
95 */
96 dccp_set_state(sk, DCCP_REQUESTING);
Arnaldo Carvalho de Meloa7f5e7f2005-12-13 23:25:31 -080097 err = inet_hash_connect(&dccp_death_row, sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070098 if (err != 0)
99 goto failure;
100
Patrick McHardy5d39a792006-01-31 17:35:35 -0800101 err = ip_route_newports(&rt, IPPROTO_DCCP, inet->sport, inet->dport,
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900102 sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700103 if (err != 0)
104 goto failure;
105
106 /* OK, now commit destination to socket. */
107 sk_setup_caps(sk, &rt->u.dst);
108
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200109 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr, inet->daddr,
110 inet->sport, inet->dport);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700111 inet->id = dp->dccps_iss ^ jiffies;
112
113 err = dccp_connect(sk);
114 rt = NULL;
115 if (err != 0)
116 goto failure;
117out:
118 return err;
119failure:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300120 /*
121 * This unhashes the socket and releases the local port, if necessary.
122 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700123 dccp_set_state(sk, DCCP_CLOSED);
124 ip_rt_put(rt);
125 sk->sk_route_caps = 0;
126 inet->dport = 0;
127 goto out;
128}
129
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800130EXPORT_SYMBOL_GPL(dccp_v4_connect);
131
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700132/*
133 * This routine does path mtu discovery as defined in RFC1191.
134 */
135static inline void dccp_do_pmtu_discovery(struct sock *sk,
136 const struct iphdr *iph,
137 u32 mtu)
138{
139 struct dst_entry *dst;
140 const struct inet_sock *inet = inet_sk(sk);
141 const struct dccp_sock *dp = dccp_sk(sk);
142
143 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
144 * send out by Linux are always < 576bytes so they should go through
145 * unfragmented).
146 */
147 if (sk->sk_state == DCCP_LISTEN)
148 return;
149
150 /* We don't check in the destentry if pmtu discovery is forbidden
151 * on this route. We just assume that no packet_to_big packets
152 * are send back when pmtu discovery is not active.
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900153 * There is a small race when the user changes this flag in the
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700154 * route, but I think that's acceptable.
155 */
156 if ((dst = __sk_dst_check(sk, 0)) == NULL)
157 return;
158
159 dst->ops->update_pmtu(dst, mtu);
160
161 /* Something is about to be wrong... Remember soft error
162 * for the case, if this connection will not able to recover.
163 */
164 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
165 sk->sk_err_soft = EMSGSIZE;
166
167 mtu = dst_mtu(dst);
168
169 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800170 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700171 dccp_sync_mss(sk, mtu);
172
173 /*
Gerrit Renker0e64e942006-10-24 16:17:51 -0700174 * From RFC 4340, sec. 14.1:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700175 *
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300176 * DCCP-Sync packets are the best choice for upward
177 * probing, since DCCP-Sync probes do not risk application
178 * data loss.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700179 */
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300180 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700181 } /* else let the usual retransmit timer handle it */
182}
183
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700184/*
185 * This routine is called by the ICMP module when it gets some sort of error
186 * condition. If err < 0 then the socket should be closed and the error
187 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
188 * After adjustment header points to the first 8 bytes of the tcp header. We
189 * need to find the appropriate port.
190 *
191 * The locking strategy used here is very "optimistic". When someone else
192 * accesses the socket the ICMP is just dropped and for some paths there is no
193 * check at all. A more general error queue to queue errors for later handling
194 * is probably better.
195 */
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800196static void dccp_v4_err(struct sk_buff *skb, u32 info)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700197{
198 const struct iphdr *iph = (struct iphdr *)skb->data;
Wei Yongjun18e1d832008-07-26 11:59:10 +0100199 const u8 offset = iph->ihl << 2;
200 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700201 struct dccp_sock *dp;
202 struct inet_sock *inet;
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300203 const int type = icmp_hdr(skb)->type;
204 const int code = icmp_hdr(skb)->code;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700205 struct sock *sk;
206 __u64 seq;
207 int err;
Pavel Emelyanovfd54d712008-07-14 23:01:40 -0700208 struct net *net = dev_net(skb->dev);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700209
Wei Yongjun18e1d832008-07-26 11:59:10 +0100210 if (skb->len < offset + sizeof(*dh) ||
211 skb->len < offset + __dccp_basic_hdr_len(dh)) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700212 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700213 return;
214 }
215
Pavel Emelyanovfd54d712008-07-14 23:01:40 -0700216 sk = inet_lookup(net, &dccp_hashinfo,
Pavel Emelyanovb9901a82008-04-13 22:30:43 -0700217 iph->daddr, dh->dccph_dport,
218 iph->saddr, dh->dccph_sport, inet_iif(skb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700219 if (sk == NULL) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700220 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700221 return;
222 }
223
224 if (sk->sk_state == DCCP_TIME_WAIT) {
YOSHIFUJI Hideaki9469c7b2006-10-10 19:41:46 -0700225 inet_twsk_put(inet_twsk(sk));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700226 return;
227 }
228
229 bh_lock_sock(sk);
230 /* If too many ICMPs get dropped on busy
231 * servers this needs to be solved differently.
232 */
233 if (sock_owned_by_user(sk))
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700234 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700235
236 if (sk->sk_state == DCCP_CLOSED)
237 goto out;
238
239 dp = dccp_sk(sk);
Gerrit Renkerfde20102007-10-24 10:12:09 -0200240 seq = dccp_hdr_seq(dh);
Gerrit Renker1238d082007-10-24 10:18:06 -0200241 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
Wei Yongjund68f0862008-07-26 11:59:10 +0100242 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700243 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700244 goto out;
245 }
246
247 switch (type) {
248 case ICMP_SOURCE_QUENCH:
249 /* Just silently ignore these. */
250 goto out;
251 case ICMP_PARAMETERPROB:
252 err = EPROTO;
253 break;
254 case ICMP_DEST_UNREACH:
255 if (code > NR_ICMP_UNREACH)
256 goto out;
257
258 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
259 if (!sock_owned_by_user(sk))
260 dccp_do_pmtu_discovery(sk, iph, info);
261 goto out;
262 }
263
264 err = icmp_err_convert[code].errno;
265 break;
266 case ICMP_TIME_EXCEEDED:
267 err = EHOSTUNREACH;
268 break;
269 default:
270 goto out;
271 }
272
273 switch (sk->sk_state) {
274 struct request_sock *req , **prev;
275 case DCCP_LISTEN:
276 if (sock_owned_by_user(sk))
277 goto out;
278 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
279 iph->daddr, iph->saddr);
280 if (!req)
281 goto out;
282
283 /*
284 * ICMPs are not backlogged, hence we cannot get an established
285 * socket here.
286 */
Ilpo Järvinen547b7922008-07-25 21:43:18 -0700287 WARN_ON(req->sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700288
289 if (seq != dccp_rsk(req)->dreq_iss) {
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700290 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700291 goto out;
292 }
293 /*
294 * Still in RESPOND, just remove it silently.
295 * There is no good way to pass the error to the newly
296 * created socket, and POSIX does not want network
297 * errors returned from accept().
298 */
299 inet_csk_reqsk_queue_drop(sk, req, prev);
300 goto out;
301
302 case DCCP_REQUESTING:
303 case DCCP_RESPOND:
304 if (!sock_owned_by_user(sk)) {
305 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
306 sk->sk_err = err;
307
308 sk->sk_error_report(sk);
309
310 dccp_done(sk);
311 } else
312 sk->sk_err_soft = err;
313 goto out;
314 }
315
316 /* If we've already connected we will keep trying
317 * until we time out, or the user gives up.
318 *
319 * rfc1122 4.2.3.9 allows to consider as hard errors
320 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
321 * but it is obsoleted by pmtu discovery).
322 *
323 * Note, that in modern internet, where routing is unreliable
324 * and in each dark corner broken firewalls sit, sending random
325 * errors ordered by their masters even this two messages finally lose
326 * their original sense (even Linux sends invalid PORT_UNREACHs)
327 *
328 * Now we are in compliance with RFCs.
329 * --ANK (980905)
330 */
331
332 inet = inet_sk(sk);
333 if (!sock_owned_by_user(sk) && inet->recverr) {
334 sk->sk_err = err;
335 sk->sk_error_report(sk);
336 } else /* Only an error on timeout */
337 sk->sk_err_soft = err;
338out:
339 bh_unlock_sock(sk);
340 sock_put(sk);
341}
342
Al Viro2bda2852006-11-14 21:28:51 -0800343static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200344 __be32 src, __be32 dst)
345{
346 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
347}
348
349void dccp_v4_send_check(struct sock *sk, int unused, struct sk_buff *skb)
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800350{
351 const struct inet_sock *inet = inet_sk(sk);
352 struct dccp_hdr *dh = dccp_hdr(skb);
353
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200354 dccp_csum_outgoing(skb);
355 dh->dccph_checksum = dccp_v4_csum_finish(skb, inet->saddr, inet->daddr);
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800356}
357
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800358EXPORT_SYMBOL_GPL(dccp_v4_send_check);
359
Gerrit Renker865e9022006-11-13 13:31:50 -0200360static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700361{
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700362 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
363 ip_hdr(skb)->saddr,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700364 dccp_hdr(skb)->dccph_dport,
365 dccp_hdr(skb)->dccph_sport);
366}
367
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700368/*
369 * The three way handshake has completed - we got a valid ACK or DATAACK -
370 * now create the new socket.
371 *
372 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
373 */
374struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
375 struct request_sock *req,
376 struct dst_entry *dst)
377{
378 struct inet_request_sock *ireq;
379 struct inet_sock *newinet;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700380 struct sock *newsk;
381
382 if (sk_acceptq_is_full(sk))
383 goto exit_overflow;
384
385 if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
386 goto exit;
387
388 newsk = dccp_create_openreq_child(sk, req, skb);
389 if (newsk == NULL)
390 goto exit;
391
392 sk_setup_caps(newsk, dst);
393
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700394 newinet = inet_sk(newsk);
395 ireq = inet_rsk(req);
396 newinet->daddr = ireq->rmt_addr;
397 newinet->rcv_saddr = ireq->loc_addr;
398 newinet->saddr = ireq->loc_addr;
399 newinet->opt = ireq->opt;
400 ireq->opt = NULL;
401 newinet->mc_index = inet_iif(skb);
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700402 newinet->mc_ttl = ip_hdr(skb)->ttl;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700403 newinet->id = jiffies;
404
405 dccp_sync_mss(newsk, dst_mtu(dst));
406
Arnaldo Carvalho de Meloab1e0a12008-02-03 04:06:04 -0800407 __inet_hash_nolisten(newsk);
408 __inet_inherit_port(sk, newsk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700409
410 return newsk;
411
412exit_overflow:
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700413 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700414exit:
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700415 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700416 dst_release(dst);
417 return NULL;
418}
419
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800420EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
421
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700422static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
423{
424 const struct dccp_hdr *dh = dccp_hdr(skb);
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700425 const struct iphdr *iph = ip_hdr(skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700426 struct sock *nsk;
427 struct request_sock **prev;
428 /* Find possible connection requests. */
429 struct request_sock *req = inet_csk_search_req(sk, &prev,
430 dh->dccph_sport,
431 iph->saddr, iph->daddr);
432 if (req != NULL)
433 return dccp_check_req(sk, skb, req, prev);
434
Pavel Emelyanovb9901a82008-04-13 22:30:43 -0700435 nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
Herbert Xu8f4910692006-08-09 15:47:12 -0700436 iph->saddr, dh->dccph_sport,
437 iph->daddr, dh->dccph_dport,
438 inet_iif(skb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700439 if (nsk != NULL) {
440 if (nsk->sk_state != DCCP_TIME_WAIT) {
441 bh_lock_sock(nsk);
442 return nsk;
443 }
YOSHIFUJI Hideaki9469c7b2006-10-10 19:41:46 -0700444 inet_twsk_put(inet_twsk(nsk));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700445 return NULL;
446 }
447
448 return sk;
449}
450
Pavel Emelyanovf5487392008-04-13 22:30:19 -0700451static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700452 struct sk_buff *skb)
453{
454 struct rtable *rt;
Eric Dumazetee6b9672008-03-05 18:30:47 -0800455 struct flowi fl = { .oif = skb->rtable->rt_iif,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700456 .nl_u = { .ip4_u =
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700457 { .daddr = ip_hdr(skb)->saddr,
458 .saddr = ip_hdr(skb)->daddr,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700459 .tos = RT_CONN_FLAGS(sk) } },
460 .proto = sk->sk_protocol,
461 .uli_u = { .ports =
462 { .sport = dccp_hdr(skb)->dccph_dport,
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300463 .dport = dccp_hdr(skb)->dccph_sport }
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200464 }
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300465 };
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700466
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700467 security_skb_classify_flow(skb, &fl);
Pavel Emelyanovf5487392008-04-13 22:30:19 -0700468 if (ip_route_output_flow(net, &rt, &fl, sk, 0)) {
Pavel Emelyanov7c73a6f2008-07-16 20:20:11 -0700469 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700470 return NULL;
471 }
472
473 return &rt->u.dst;
474}
475
Denis V. Lunevfd80eb92008-02-29 11:43:03 -0800476static int dccp_v4_send_response(struct sock *sk, struct request_sock *req)
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200477{
478 int err = -1;
479 struct sk_buff *skb;
Denis V. Lunevfd80eb92008-02-29 11:43:03 -0800480 struct dst_entry *dst;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200481
Denis V. Lunevfd80eb92008-02-29 11:43:03 -0800482 dst = inet_csk_route_req(sk, req);
483 if (dst == NULL)
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200484 goto out;
485
486 skb = dccp_make_response(sk, dst, req);
487 if (skb != NULL) {
488 const struct inet_request_sock *ireq = inet_rsk(req);
489 struct dccp_hdr *dh = dccp_hdr(skb);
490
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200491 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
492 ireq->rmt_addr);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200493 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
494 ireq->rmt_addr,
495 ireq->opt);
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200496 err = net_xmit_eval(err);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200497 }
498
499out:
500 dst_release(dst);
501 return err;
502}
503
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800504static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700505{
506 int err;
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700507 const struct iphdr *rxiph;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700508 struct sk_buff *skb;
509 struct dst_entry *dst;
Pavel Emelyanovb76c4b22008-04-13 22:29:59 -0700510 struct net *net = dev_net(rxskb->dst->dev);
511 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700512
513 /* Never send a reset in response to a reset. */
Gerrit Renkere356d372007-09-26 14:35:19 -0300514 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700515 return;
516
Eric Dumazetee6b9672008-03-05 18:30:47 -0800517 if (rxskb->rtable->rt_type != RTN_LOCAL)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700518 return;
519
Pavel Emelyanovf5487392008-04-13 22:30:19 -0700520 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700521 if (dst == NULL)
522 return;
523
Pavel Emelyanov7b1cffa2008-04-13 22:29:37 -0700524 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700525 if (skb == NULL)
526 goto out;
527
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700528 rxiph = ip_hdr(rxskb);
Gerrit Renkere356d372007-09-26 14:35:19 -0300529 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
530 rxiph->daddr);
531 skb->dst = dst_clone(dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700532
Pavel Emelyanov7b1cffa2008-04-13 22:29:37 -0700533 bh_lock_sock(ctl_sk);
534 err = ip_build_and_send_pkt(skb, ctl_sk,
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700535 rxiph->daddr, rxiph->saddr, NULL);
Pavel Emelyanov7b1cffa2008-04-13 22:29:37 -0700536 bh_unlock_sock(ctl_sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700537
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200538 if (net_xmit_eval(err) == 0) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700539 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
540 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
541 }
542out:
543 dst_release(dst);
544}
545
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200546static void dccp_v4_reqsk_destructor(struct request_sock *req)
547{
548 kfree(inet_rsk(req)->opt);
549}
550
551static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
552 .family = PF_INET,
553 .obj_size = sizeof(struct dccp_request_sock),
554 .rtx_syn_ack = dccp_v4_send_response,
555 .send_ack = dccp_reqsk_send_ack,
556 .destructor = dccp_v4_reqsk_destructor,
557 .send_reset = dccp_v4_ctl_send_reset,
558};
559
560int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
561{
562 struct inet_request_sock *ireq;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200563 struct request_sock *req;
564 struct dccp_request_sock *dreq;
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200565 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200566 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200567
568 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
Eric Dumazetee6b9672008-03-05 18:30:47 -0800569 if (skb->rtable->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
Gerrit Renker4a5409a2007-10-04 14:52:28 -0700570 return 0; /* discard, don't send a reset here */
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200571
572 if (dccp_bad_service_code(sk, service)) {
Gerrit Renker4a5409a2007-10-04 14:52:28 -0700573 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200574 goto drop;
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200575 }
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200576 /*
577 * TW buckets are converted to open requests without
578 * limitations, they conserve resources and peer is
579 * evidently real one.
580 */
Gerrit Renker4a5409a2007-10-04 14:52:28 -0700581 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200582 if (inet_csk_reqsk_queue_is_full(sk))
583 goto drop;
584
585 /*
586 * Accept backlog is full. If we have already queued enough
587 * of warm entries in syn queue, drop request. It is better than
588 * clogging syn queue with openreqs with exponentially increasing
589 * timeout.
590 */
591 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
592 goto drop;
593
Arnaldo Carvalho de Meloce4a7d02008-06-10 12:39:35 -0700594 req = inet_reqsk_alloc(&dccp_request_sock_ops);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200595 if (req == NULL)
596 goto drop;
597
Gerrit Renkercf557922006-11-10 16:08:37 -0200598 dccp_reqsk_init(req, skb);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200599
Gerrit Renker8b819412007-12-13 12:29:24 -0200600 dreq = dccp_rsk(req);
601 if (dccp_parse_options(sk, dreq, skb))
602 goto drop_and_free;
603
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200604 if (security_inet_conn_request(sk, skb, req))
605 goto drop_and_free;
606
607 ireq = inet_rsk(req);
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700608 ireq->loc_addr = ip_hdr(skb)->daddr;
609 ireq->rmt_addr = ip_hdr(skb)->saddr;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200610
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200611 /*
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200612 * Step 3: Process LISTEN state
613 *
614 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
615 *
616 * In fact we defer setting S.GSR, S.SWL, S.SWH to
617 * dccp_create_openreq_child.
618 */
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200619 dreq->dreq_isr = dcb->dccpd_seq;
Gerrit Renker865e9022006-11-13 13:31:50 -0200620 dreq->dreq_iss = dccp_v4_init_sequence(skb);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200621 dreq->dreq_service = service;
622
Denis V. Lunevfd80eb92008-02-29 11:43:03 -0800623 if (dccp_v4_send_response(sk, req))
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200624 goto drop_and_free;
625
626 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
627 return 0;
628
629drop_and_free:
630 reqsk_free(req);
631drop:
632 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200633 return -1;
634}
635
636EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
637
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700638int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
639{
640 struct dccp_hdr *dh = dccp_hdr(skb);
641
642 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
643 if (dccp_rcv_established(sk, skb, dh, skb->len))
644 goto reset;
645 return 0;
646 }
647
648 /*
649 * Step 3: Process LISTEN state
Gerrit Renkerd83ca5a2006-11-10 16:29:14 -0200650 * If P.type == Request or P contains a valid Init Cookie option,
651 * (* Must scan the packet's options to check for Init
652 * Cookies. Only Init Cookies are processed here,
653 * however; other options are processed in Step 8. This
654 * scan need only be performed if the endpoint uses Init
655 * Cookies *)
656 * (* Generate a new socket and switch to that socket *)
657 * Set S := new socket for this port pair
658 * S.state = RESPOND
659 * Choose S.ISS (initial seqno) or set from Init Cookies
660 * Initialize S.GAR := S.ISS
661 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
662 * Continue with S.state == RESPOND
663 * (* A Response packet will be generated in Step 11 *)
664 * Otherwise,
665 * Generate Reset(No Connection) unless P.type == Reset
666 * Drop packet and return
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700667 *
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300668 * NOTE: the check for the packet types is done in
669 * dccp_rcv_state_process
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700670 */
671 if (sk->sk_state == DCCP_LISTEN) {
672 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
673
674 if (nsk == NULL)
675 goto discard;
676
677 if (nsk != sk) {
678 if (dccp_child_process(sk, nsk, skb))
679 goto reset;
680 return 0;
681 }
682 }
683
684 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
685 goto reset;
686 return 0;
687
688reset:
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800689 dccp_v4_ctl_send_reset(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700690discard:
691 kfree_skb(skb);
692 return 0;
693}
694
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800695EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
696
Gerrit Renker09dbc382006-11-14 12:57:34 -0200697/**
698 * dccp_invalid_packet - check for malformed packets
699 * Implements RFC 4340, 8.5: Step 1: Check header basics
700 * Packets that fail these checks are ignored and do not receive Resets.
701 */
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800702int dccp_invalid_packet(struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700703{
704 const struct dccp_hdr *dh;
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200705 unsigned int cscov;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700706
707 if (skb->pkt_type != PACKET_HOST)
708 return 1;
709
Gerrit Renker09dbc382006-11-14 12:57:34 -0200710 /* If the packet is shorter than 12 bytes, drop packet and return */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700711 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200712 DCCP_WARN("pskb_may_pull failed\n");
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700713 return 1;
714 }
715
716 dh = dccp_hdr(skb);
717
Gerrit Renker09dbc382006-11-14 12:57:34 -0200718 /* If P.type is not understood, drop packet and return */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700719 if (dh->dccph_type >= DCCP_PKT_INVALID) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200720 DCCP_WARN("invalid packet type\n");
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700721 return 1;
722 }
723
724 /*
Gerrit Renker09dbc382006-11-14 12:57:34 -0200725 * If P.Data Offset is too small for packet type, drop packet and return
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700726 */
727 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200728 DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700729 return 1;
730 }
Gerrit Renker09dbc382006-11-14 12:57:34 -0200731 /*
732 * If P.Data Offset is too too large for packet, drop packet and return
733 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700734 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200735 DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700736 return 1;
737 }
738
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700739 /*
740 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
741 * has short sequence numbers), drop packet and return
742 */
Wei Yongjun6079a462008-05-27 06:22:38 -0700743 if ((dh->dccph_type < DCCP_PKT_DATA ||
744 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200745 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
746 dccp_packet_name(dh->dccph_type));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700747 return 1;
748 }
749
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200750 /*
751 * If P.CsCov is too large for the packet size, drop packet and return.
752 * This must come _before_ checksumming (not as RFC 4340 suggests).
753 */
754 cscov = dccp_csum_coverage(skb);
755 if (cscov > skb->len) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200756 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
757 dh->dccph_cscov, skb->len);
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200758 return 1;
759 }
760
761 /* If header checksum is incorrect, drop packet and return.
762 * (This step is completed in the AF-dependent functions.) */
763 skb->csum = skb_checksum(skb, 0, cscov, 0);
764
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700765 return 0;
766}
767
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800768EXPORT_SYMBOL_GPL(dccp_invalid_packet);
769
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700770/* this is called when real data arrives */
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800771static int dccp_v4_rcv(struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700772{
773 const struct dccp_hdr *dh;
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700774 const struct iphdr *iph;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700775 struct sock *sk;
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200776 int min_cov;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700777
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200778 /* Step 1: Check header basics */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700779
780 if (dccp_invalid_packet(skb))
781 goto discard_it;
782
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700783 iph = ip_hdr(skb);
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200784 /* Step 1: If header checksum is incorrect, drop packet and return */
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700785 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200786 DCCP_WARN("dropped packet with invalid checksum\n");
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800787 goto discard_it;
788 }
789
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700790 dh = dccp_hdr(skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700791
Gerrit Renkerfde20102007-10-24 10:12:09 -0200792 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700793 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
794
795 dccp_pr_debug("%8.8s "
796 "src=%u.%u.%u.%u@%-5d "
797 "dst=%u.%u.%u.%u@%-5d seq=%llu",
798 dccp_packet_name(dh->dccph_type),
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700799 NIPQUAD(iph->saddr), ntohs(dh->dccph_sport),
800 NIPQUAD(iph->daddr), ntohs(dh->dccph_dport),
David S. Millerf6ccf552005-08-09 20:27:14 -0700801 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700802
803 if (dccp_packet_without_ack(skb)) {
804 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
805 dccp_pr_debug_cat("\n");
806 } else {
807 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
Gerrit Renkerd23c7102006-11-10 11:46:34 -0200808 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
David S. Millerf6ccf552005-08-09 20:27:14 -0700809 DCCP_SKB_CB(skb)->dccpd_ack_seq);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700810 }
811
812 /* Step 2:
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200813 * Look up flow ID in table and get corresponding socket */
Pavel Emelyanovb9901a82008-04-13 22:30:43 -0700814 sk = __inet_lookup(dev_net(skb->dst->dev), &dccp_hashinfo,
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700815 iph->saddr, dh->dccph_sport,
816 iph->daddr, dh->dccph_dport, inet_iif(skb));
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200817 /*
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700818 * Step 2:
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200819 * If no socket ...
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700820 */
821 if (sk == NULL) {
822 dccp_pr_debug("failed to look up flow ID in table and "
823 "get corresponding socket\n");
824 goto no_dccp_socket;
825 }
826
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200827 /*
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700828 * Step 2:
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200829 * ... or S.state == TIMEWAIT,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700830 * Generate Reset(No Connection) unless P.type == Reset
831 * Drop packet and return
832 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700833 if (sk->sk_state == DCCP_TIME_WAIT) {
Gerrit Renkerd23c7102006-11-10 11:46:34 -0200834 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
835 inet_twsk_put(inet_twsk(sk));
836 goto no_dccp_socket;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700837 }
838
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200839 /*
840 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200841 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
842 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200843 */
844 min_cov = dccp_sk(sk)->dccps_pcrlen;
845 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
846 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
847 dh->dccph_cscov, min_cov);
848 /* FIXME: "Such packets SHOULD be reported using Data Dropped
849 * options (Section 11.7) with Drop Code 0, Protocol
850 * Constraints." */
851 goto discard_and_relse;
852 }
853
Arnaldo Carvalho de Melo25995ff2005-12-27 02:42:22 -0200854 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700855 goto discard_and_relse;
Patrick McHardyeb9c7eb2006-01-06 23:06:30 -0800856 nf_reset(skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700857
Arnaldo Carvalho de Melo58a5a7b2006-11-16 14:06:06 -0200858 return sk_receive_skb(sk, skb, 1);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700859
860no_dccp_socket:
861 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
862 goto discard_it;
863 /*
864 * Step 2:
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200865 * If no socket ...
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700866 * Generate Reset(No Connection) unless P.type == Reset
867 * Drop packet and return
868 */
869 if (dh->dccph_type != DCCP_PKT_RESET) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300870 DCCP_SKB_CB(skb)->dccpd_reset_code =
871 DCCP_RESET_CODE_NO_CONNECTION;
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800872 dccp_v4_ctl_send_reset(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700873 }
874
875discard_it:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700876 kfree_skb(skb);
877 return 0;
878
879discard_and_relse:
880 sock_put(sk);
881 goto discard_it;
882}
883
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800884static struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800885 .queue_xmit = ip_queue_xmit,
886 .send_check = dccp_v4_send_check,
887 .rebuild_header = inet_sk_rebuild_header,
888 .conn_request = dccp_v4_conn_request,
889 .syn_recv_sock = dccp_v4_request_recv_sock,
890 .net_header_len = sizeof(struct iphdr),
891 .setsockopt = ip_setsockopt,
892 .getsockopt = ip_getsockopt,
893 .addr2sockaddr = inet_csk_addr2sockaddr,
894 .sockaddr_len = sizeof(struct sockaddr_in),
Arnaldo Carvalho de Meloab1e0a12008-02-03 04:06:04 -0800895 .bind_conflict = inet_csk_bind_conflict,
Dmitry Mishin3fdadf72006-03-20 22:45:21 -0800896#ifdef CONFIG_COMPAT
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800897 .compat_setsockopt = compat_ip_setsockopt,
898 .compat_getsockopt = compat_ip_getsockopt,
Dmitry Mishin3fdadf72006-03-20 22:45:21 -0800899#endif
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800900};
901
Arnaldo Carvalho de Melo3e0fadc2006-03-20 21:23:15 -0800902static int dccp_v4_init_sock(struct sock *sk)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700903{
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -0800904 static __u8 dccp_v4_ctl_sock_initialized;
905 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700906
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -0800907 if (err == 0) {
908 if (unlikely(!dccp_v4_ctl_sock_initialized))
909 dccp_v4_ctl_sock_initialized = 1;
Arnaldo Carvalho de Melo3e0fadc2006-03-20 21:23:15 -0800910 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -0800911 }
912
Arnaldo Carvalho de Melo3e0fadc2006-03-20 21:23:15 -0800913 return err;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700914}
915
Arnaldo Carvalho de Melo6d6ee432005-12-13 23:25:19 -0800916static struct timewait_sock_ops dccp_timewait_sock_ops = {
917 .twsk_obj_size = sizeof(struct inet_timewait_sock),
918};
919
Adrian Bunk5e0817f2006-03-20 21:58:29 -0800920static struct proto dccp_v4_prot = {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700921 .name = "DCCP",
922 .owner = THIS_MODULE,
923 .close = dccp_close,
924 .connect = dccp_v4_connect,
925 .disconnect = dccp_disconnect,
926 .ioctl = dccp_ioctl,
927 .init = dccp_v4_init_sock,
928 .setsockopt = dccp_setsockopt,
929 .getsockopt = dccp_getsockopt,
930 .sendmsg = dccp_sendmsg,
931 .recvmsg = dccp_recvmsg,
932 .backlog_rcv = dccp_v4_do_rcv,
Arnaldo Carvalho de Meloab1e0a12008-02-03 04:06:04 -0800933 .hash = inet_hash,
934 .unhash = inet_unhash,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700935 .accept = inet_csk_accept,
Arnaldo Carvalho de Meloab1e0a12008-02-03 04:06:04 -0800936 .get_port = inet_csk_get_port,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700937 .shutdown = dccp_shutdown,
Arnaldo Carvalho de Melo3e0fadc2006-03-20 21:23:15 -0800938 .destroy = dccp_destroy_sock,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700939 .orphan_count = &dccp_orphan_count,
940 .max_header = MAX_DCCP_HEADER,
941 .obj_size = sizeof(struct dccp_sock),
942 .rsk_prot = &dccp_request_sock_ops,
Arnaldo Carvalho de Melo6d6ee432005-12-13 23:25:19 -0800943 .twsk_prot = &dccp_timewait_sock_ops,
Pavel Emelyanov39d8cda2008-03-22 16:50:58 -0700944 .h.hashinfo = &dccp_hashinfo,
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800945#ifdef CONFIG_COMPAT
946 .compat_setsockopt = compat_dccp_setsockopt,
947 .compat_getsockopt = compat_dccp_getsockopt,
948#endif
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700949};
Arnaldo Carvalho de Melo6d6ee432005-12-13 23:25:19 -0800950
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800951static struct net_protocol dccp_v4_protocol = {
952 .handler = dccp_v4_rcv,
953 .err_handler = dccp_v4_err,
954 .no_policy = 1,
Pavel Emelyanovfc5f8582008-04-13 22:31:05 -0700955 .netns_ok = 1,
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800956};
957
958static const struct proto_ops inet_dccp_ops = {
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800959 .family = PF_INET,
960 .owner = THIS_MODULE,
961 .release = inet_release,
962 .bind = inet_bind,
963 .connect = inet_stream_connect,
964 .socketpair = sock_no_socketpair,
965 .accept = inet_accept,
966 .getname = inet_getname,
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800967 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800968 .poll = dccp_poll,
969 .ioctl = inet_ioctl,
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800970 /* FIXME: work on inet_listen to rename it to sock_common_listen */
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800971 .listen = inet_dccp_listen,
972 .shutdown = inet_shutdown,
973 .setsockopt = sock_common_setsockopt,
974 .getsockopt = sock_common_getsockopt,
975 .sendmsg = inet_sendmsg,
976 .recvmsg = sock_common_recvmsg,
977 .mmap = sock_no_mmap,
978 .sendpage = sock_no_sendpage,
Dmitry Mishin3fdadf72006-03-20 22:45:21 -0800979#ifdef CONFIG_COMPAT
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800980 .compat_setsockopt = compat_sock_common_setsockopt,
981 .compat_getsockopt = compat_sock_common_getsockopt,
Dmitry Mishin3fdadf72006-03-20 22:45:21 -0800982#endif
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800983};
984
985static struct inet_protosw dccp_v4_protosw = {
986 .type = SOCK_DCCP,
987 .protocol = IPPROTO_DCCP,
988 .prot = &dccp_v4_prot,
989 .ops = &inet_dccp_ops,
990 .capability = -1,
991 .no_check = 0,
992 .flags = INET_PROTOSW_ICSK,
993};
994
Pavel Emelyanov72a2d612008-04-13 22:29:13 -0700995static int dccp_v4_init_net(struct net *net)
996{
Pavel Emelyanovb76c4b22008-04-13 22:29:59 -0700997 int err;
998
999 err = inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1000 SOCK_DCCP, IPPROTO_DCCP, net);
1001 return err;
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001002}
1003
1004static void dccp_v4_exit_net(struct net *net)
1005{
Pavel Emelyanovb76c4b22008-04-13 22:29:59 -07001006 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001007}
1008
1009static struct pernet_operations dccp_v4_ops = {
1010 .init = dccp_v4_init_net,
1011 .exit = dccp_v4_exit_net,
1012};
1013
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001014static int __init dccp_v4_init(void)
1015{
1016 int err = proto_register(&dccp_v4_prot, 1);
1017
1018 if (err != 0)
1019 goto out;
1020
1021 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1022 if (err != 0)
1023 goto out_proto_unregister;
1024
1025 inet_register_protosw(&dccp_v4_protosw);
1026
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001027 err = register_pernet_subsys(&dccp_v4_ops);
1028 if (err)
1029 goto out_destroy_ctl_sock;
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001030out:
1031 return err;
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001032out_destroy_ctl_sock:
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001033 inet_unregister_protosw(&dccp_v4_protosw);
1034 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1035out_proto_unregister:
1036 proto_unregister(&dccp_v4_prot);
1037 goto out;
1038}
1039
1040static void __exit dccp_v4_exit(void)
1041{
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001042 unregister_pernet_subsys(&dccp_v4_ops);
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001043 inet_unregister_protosw(&dccp_v4_protosw);
1044 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1045 proto_unregister(&dccp_v4_prot);
1046}
1047
1048module_init(dccp_v4_init);
1049module_exit(dccp_v4_exit);
1050
1051/*
1052 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1053 * values directly, Also cover the case where the protocol is not specified,
1054 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1055 */
Jean Delvare7131c6c2007-10-21 16:45:03 -07001056MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1057MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001058MODULE_LICENSE("GPL");
1059MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1060MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");