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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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090015#include <linux/slab.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070016#include <linux/module.h>
17#include <linux/skbuff.h>
18#include <linux/random.h>
19
20#include <net/icmp.h>
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -080021#include <net/inet_common.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070022#include <net/inet_hashtables.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020023#include <net/inet_sock.h>
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -080024#include <net/protocol.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070025#include <net/sock.h>
Arnaldo Carvalho de Melo6d6ee432005-12-13 23:25:19 -080026#include <net/timewait_sock.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070027#include <net/tcp_states.h>
28#include <net/xfrm.h>
David S. Miller6e5714e2011-08-03 20:50:44 -070029#include <net/secure_seq.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070030
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070031#include "ackvec.h"
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070032#include "ccid.h"
33#include "dccp.h"
Andrea Bittauafe00252006-03-20 17:43:56 -080034#include "feat.h"
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070035
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -080036/*
Pavel Emelyanov13f51d82008-04-14 02:38:45 -070037 * The per-net dccp.v4_ctl_sk socket is used for responding to
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -080038 * the Out-of-the-blue (OOTB) packets. A control sock will be created
39 * for this socket at the initialization time.
40 */
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -080041
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -080042int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070043{
David S. Miller2d7192d2011-04-26 13:28:44 -070044 const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070045 struct inet_sock *inet = inet_sk(sk);
46 struct dccp_sock *dp = dccp_sk(sk);
David S. Millerdca8b082011-02-24 13:38:12 -080047 __be16 orig_sport, orig_dport;
Al Virobada8ad2006-09-26 21:27:15 -070048 __be32 daddr, nexthop;
David S. Miller2c427582011-05-06 16:10:41 -070049 struct flowi4 *fl4;
David S. Miller2d7192d2011-04-26 13:28:44 -070050 struct rtable *rt;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070051 int err;
Eric Dumazetf6d8bd02011-04-21 09:45:37 +000052 struct ip_options_rcu *inet_opt;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070053
54 dp->dccps_role = DCCP_ROLE_CLIENT;
55
56 if (addr_len < sizeof(struct sockaddr_in))
57 return -EINVAL;
58
59 if (usin->sin_family != AF_INET)
60 return -EAFNOSUPPORT;
61
62 nexthop = daddr = usin->sin_addr.s_addr;
Eric Dumazetf6d8bd02011-04-21 09:45:37 +000063
64 inet_opt = rcu_dereference_protected(inet->inet_opt,
65 sock_owned_by_user(sk));
66 if (inet_opt != NULL && inet_opt->opt.srr) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070067 if (daddr == 0)
68 return -EINVAL;
Eric Dumazetf6d8bd02011-04-21 09:45:37 +000069 nexthop = inet_opt->opt.faddr;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070070 }
71
David S. Millerdca8b082011-02-24 13:38:12 -080072 orig_sport = inet->inet_sport;
73 orig_dport = usin->sin_port;
David S. Miller2c427582011-05-06 16:10:41 -070074 fl4 = &inet->cork.fl.u.ip4;
75 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
David S. Millerb23dd4f2011-03-02 14:31:35 -080076 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
77 IPPROTO_DCCP,
78 orig_sport, orig_dport, sk, true);
79 if (IS_ERR(rt))
80 return PTR_ERR(rt);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070081
82 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
83 ip_rt_put(rt);
84 return -ENETUNREACH;
85 }
86
Eric Dumazetf6d8bd02011-04-21 09:45:37 +000087 if (inet_opt == NULL || !inet_opt->opt.srr)
David S. Miller2c427582011-05-06 16:10:41 -070088 daddr = fl4->daddr;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070089
Eric Dumazetc720c7e2009-10-15 06:30:45 +000090 if (inet->inet_saddr == 0)
David S. Miller2c427582011-05-06 16:10:41 -070091 inet->inet_saddr = fl4->saddr;
Eric Dumazetc720c7e2009-10-15 06:30:45 +000092 inet->inet_rcv_saddr = inet->inet_saddr;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070093
Eric Dumazetc720c7e2009-10-15 06:30:45 +000094 inet->inet_dport = usin->sin_port;
95 inet->inet_daddr = daddr;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070096
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -080097 inet_csk(sk)->icsk_ext_hdr_len = 0;
Eric Dumazetf6d8bd02011-04-21 09:45:37 +000098 if (inet_opt)
99 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700100 /*
101 * Socket identity is still unknown (sport may be zero).
102 * However we set state to DCCP_REQUESTING and not releasing socket
103 * lock select source port, enter ourselves into the hash tables and
104 * complete initialization after this.
105 */
106 dccp_set_state(sk, DCCP_REQUESTING);
Arnaldo Carvalho de Meloa7f5e7f2005-12-13 23:25:31 -0800107 err = inet_hash_connect(&dccp_death_row, sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700108 if (err != 0)
109 goto failure;
110
David S. Miller2c427582011-05-06 16:10:41 -0700111 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
David S. Millerb23dd4f2011-03-02 14:31:35 -0800112 inet->inet_sport, inet->inet_dport, sk);
113 if (IS_ERR(rt)) {
RongQing.Li525c6462011-11-21 16:45:26 -0500114 err = PTR_ERR(rt);
David S. Millerb23dd4f2011-03-02 14:31:35 -0800115 rt = NULL;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700116 goto failure;
David S. Millerb23dd4f2011-03-02 14:31:35 -0800117 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700118 /* OK, now commit destination to socket. */
Changli Gaod8d1f302010-06-10 23:31:35 -0700119 sk_setup_caps(sk, &rt->dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700120
Eric Dumazetc720c7e2009-10-15 06:30:45 +0000121 dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
122 inet->inet_daddr,
123 inet->inet_sport,
124 inet->inet_dport);
125 inet->inet_id = dp->dccps_iss ^ jiffies;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700126
127 err = dccp_connect(sk);
128 rt = NULL;
129 if (err != 0)
130 goto failure;
131out:
132 return err;
133failure:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300134 /*
135 * This unhashes the socket and releases the local port, if necessary.
136 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700137 dccp_set_state(sk, DCCP_CLOSED);
138 ip_rt_put(rt);
139 sk->sk_route_caps = 0;
Eric Dumazetc720c7e2009-10-15 06:30:45 +0000140 inet->inet_dport = 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700141 goto out;
142}
143
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800144EXPORT_SYMBOL_GPL(dccp_v4_connect);
145
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700146/*
147 * This routine does path mtu discovery as defined in RFC1191.
148 */
149static inline void dccp_do_pmtu_discovery(struct sock *sk,
150 const struct iphdr *iph,
151 u32 mtu)
152{
153 struct dst_entry *dst;
154 const struct inet_sock *inet = inet_sk(sk);
155 const struct dccp_sock *dp = dccp_sk(sk);
156
157 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
158 * send out by Linux are always < 576bytes so they should go through
159 * unfragmented).
160 */
161 if (sk->sk_state == DCCP_LISTEN)
162 return;
163
David S. Miller80d0a692012-07-16 03:28:06 -0700164 dst = inet_csk_update_pmtu(sk, mtu);
165 if (!dst)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700166 return;
167
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700168 /* Something is about to be wrong... Remember soft error
169 * for the case, if this connection will not able to recover.
170 */
171 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
172 sk->sk_err_soft = EMSGSIZE;
173
174 mtu = dst_mtu(dst);
175
176 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800177 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700178 dccp_sync_mss(sk, mtu);
179
180 /*
Gerrit Renker0e64e942006-10-24 16:17:51 -0700181 * From RFC 4340, sec. 14.1:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700182 *
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300183 * DCCP-Sync packets are the best choice for upward
184 * probing, since DCCP-Sync probes do not risk application
185 * data loss.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700186 */
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300187 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700188 } /* else let the usual retransmit timer handle it */
189}
190
David S. Miller55be7a92012-07-11 21:27:49 -0700191static void dccp_do_redirect(struct sk_buff *skb, struct sock *sk)
192{
193 struct dst_entry *dst = __sk_dst_check(sk, 0);
194
David S. Miller1ed5c482012-07-12 00:41:25 -0700195 if (dst)
David S. Miller6700c272012-07-17 03:29:28 -0700196 dst->ops->redirect(dst, sk, skb);
David S. Miller55be7a92012-07-11 21:27:49 -0700197}
198
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700199/*
200 * This routine is called by the ICMP module when it gets some sort of error
201 * condition. If err < 0 then the socket should be closed and the error
202 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
203 * After adjustment header points to the first 8 bytes of the tcp header. We
204 * need to find the appropriate port.
205 *
206 * The locking strategy used here is very "optimistic". When someone else
207 * accesses the socket the ICMP is just dropped and for some paths there is no
208 * check at all. A more general error queue to queue errors for later handling
209 * is probably better.
210 */
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800211static void dccp_v4_err(struct sk_buff *skb, u32 info)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700212{
213 const struct iphdr *iph = (struct iphdr *)skb->data;
Wei Yongjun18e1d832008-07-26 11:59:10 +0100214 const u8 offset = iph->ihl << 2;
215 const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700216 struct dccp_sock *dp;
217 struct inet_sock *inet;
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300218 const int type = icmp_hdr(skb)->type;
219 const int code = icmp_hdr(skb)->code;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700220 struct sock *sk;
221 __u64 seq;
222 int err;
Pavel Emelyanovfd54d712008-07-14 23:01:40 -0700223 struct net *net = dev_net(skb->dev);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700224
Wei Yongjun18e1d832008-07-26 11:59:10 +0100225 if (skb->len < offset + sizeof(*dh) ||
226 skb->len < offset + __dccp_basic_hdr_len(dh)) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700227 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700228 return;
229 }
230
Pavel Emelyanovfd54d712008-07-14 23:01:40 -0700231 sk = inet_lookup(net, &dccp_hashinfo,
Pavel Emelyanovb9901a82008-04-13 22:30:43 -0700232 iph->daddr, dh->dccph_dport,
233 iph->saddr, dh->dccph_sport, inet_iif(skb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700234 if (sk == NULL) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700235 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700236 return;
237 }
238
239 if (sk->sk_state == DCCP_TIME_WAIT) {
YOSHIFUJI Hideaki9469c7b2006-10-10 19:41:46 -0700240 inet_twsk_put(inet_twsk(sk));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700241 return;
242 }
243
244 bh_lock_sock(sk);
245 /* If too many ICMPs get dropped on busy
246 * servers this needs to be solved differently.
247 */
248 if (sock_owned_by_user(sk))
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700249 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700250
251 if (sk->sk_state == DCCP_CLOSED)
252 goto out;
253
254 dp = dccp_sk(sk);
Gerrit Renkerfde20102007-10-24 10:12:09 -0200255 seq = dccp_hdr_seq(dh);
Gerrit Renker1238d082007-10-24 10:18:06 -0200256 if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
Wei Yongjund68f0862008-07-26 11:59:10 +0100257 !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700258 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700259 goto out;
260 }
261
262 switch (type) {
David S. Miller55be7a92012-07-11 21:27:49 -0700263 case ICMP_REDIRECT:
264 dccp_do_redirect(skb, sk);
265 goto out;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700266 case ICMP_SOURCE_QUENCH:
267 /* Just silently ignore these. */
268 goto out;
269 case ICMP_PARAMETERPROB:
270 err = EPROTO;
271 break;
272 case ICMP_DEST_UNREACH:
273 if (code > NR_ICMP_UNREACH)
274 goto out;
275
276 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
277 if (!sock_owned_by_user(sk))
278 dccp_do_pmtu_discovery(sk, iph, info);
279 goto out;
280 }
281
282 err = icmp_err_convert[code].errno;
283 break;
284 case ICMP_TIME_EXCEEDED:
285 err = EHOSTUNREACH;
286 break;
287 default:
288 goto out;
289 }
290
291 switch (sk->sk_state) {
292 struct request_sock *req , **prev;
293 case DCCP_LISTEN:
294 if (sock_owned_by_user(sk))
295 goto out;
296 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
297 iph->daddr, iph->saddr);
298 if (!req)
299 goto out;
300
301 /*
302 * ICMPs are not backlogged, hence we cannot get an established
303 * socket here.
304 */
Ilpo Järvinen547b7922008-07-25 21:43:18 -0700305 WARN_ON(req->sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700306
Samuel Jerof541fb72012-02-26 18:22:02 -0700307 if (!between48(seq, dccp_rsk(req)->dreq_iss,
308 dccp_rsk(req)->dreq_gss)) {
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700309 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700310 goto out;
311 }
312 /*
313 * Still in RESPOND, just remove it silently.
314 * There is no good way to pass the error to the newly
315 * created socket, and POSIX does not want network
316 * errors returned from accept().
317 */
318 inet_csk_reqsk_queue_drop(sk, req, prev);
319 goto out;
320
321 case DCCP_REQUESTING:
322 case DCCP_RESPOND:
323 if (!sock_owned_by_user(sk)) {
324 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
325 sk->sk_err = err;
326
327 sk->sk_error_report(sk);
328
329 dccp_done(sk);
330 } else
331 sk->sk_err_soft = err;
332 goto out;
333 }
334
335 /* If we've already connected we will keep trying
336 * until we time out, or the user gives up.
337 *
338 * rfc1122 4.2.3.9 allows to consider as hard errors
339 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
340 * but it is obsoleted by pmtu discovery).
341 *
342 * Note, that in modern internet, where routing is unreliable
343 * and in each dark corner broken firewalls sit, sending random
344 * errors ordered by their masters even this two messages finally lose
345 * their original sense (even Linux sends invalid PORT_UNREACHs)
346 *
347 * Now we are in compliance with RFCs.
348 * --ANK (980905)
349 */
350
351 inet = inet_sk(sk);
352 if (!sock_owned_by_user(sk) && inet->recverr) {
353 sk->sk_err = err;
354 sk->sk_error_report(sk);
355 } else /* Only an error on timeout */
356 sk->sk_err_soft = err;
357out:
358 bh_unlock_sock(sk);
359 sock_put(sk);
360}
361
Al Viro2bda2852006-11-14 21:28:51 -0800362static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200363 __be32 src, __be32 dst)
364{
365 return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
366}
367
Herbert Xubb296242010-04-11 02:15:55 +0000368void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800369{
370 const struct inet_sock *inet = inet_sk(sk);
371 struct dccp_hdr *dh = dccp_hdr(skb);
372
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200373 dccp_csum_outgoing(skb);
Eric Dumazetc720c7e2009-10-15 06:30:45 +0000374 dh->dccph_checksum = dccp_v4_csum_finish(skb,
375 inet->inet_saddr,
376 inet->inet_daddr);
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800377}
378
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800379EXPORT_SYMBOL_GPL(dccp_v4_send_check);
380
Gerrit Renker865e9022006-11-13 13:31:50 -0200381static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700382{
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700383 return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
384 ip_hdr(skb)->saddr,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700385 dccp_hdr(skb)->dccph_dport,
386 dccp_hdr(skb)->dccph_sport);
387}
388
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700389/*
390 * The three way handshake has completed - we got a valid ACK or DATAACK -
391 * now create the new socket.
392 *
393 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
394 */
395struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
396 struct request_sock *req,
397 struct dst_entry *dst)
398{
399 struct inet_request_sock *ireq;
400 struct inet_sock *newinet;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700401 struct sock *newsk;
402
403 if (sk_acceptq_is_full(sk))
404 goto exit_overflow;
405
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700406 newsk = dccp_create_openreq_child(sk, req, skb);
407 if (newsk == NULL)
Balazs Scheidler093d2822010-10-21 13:06:43 +0200408 goto exit_nonewsk;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700409
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700410 newinet = inet_sk(newsk);
411 ireq = inet_rsk(req);
Eric Dumazetc720c7e2009-10-15 06:30:45 +0000412 newinet->inet_daddr = ireq->rmt_addr;
413 newinet->inet_rcv_saddr = ireq->loc_addr;
414 newinet->inet_saddr = ireq->loc_addr;
Eric Dumazetf6d8bd02011-04-21 09:45:37 +0000415 newinet->inet_opt = ireq->opt;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700416 ireq->opt = NULL;
417 newinet->mc_index = inet_iif(skb);
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700418 newinet->mc_ttl = ip_hdr(skb)->ttl;
Eric Dumazetc720c7e2009-10-15 06:30:45 +0000419 newinet->inet_id = jiffies;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700420
David S. Miller0e734412011-05-08 15:28:03 -0700421 if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
422 goto put_and_exit;
423
424 sk_setup_caps(newsk, dst);
425
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700426 dccp_sync_mss(newsk, dst_mtu(dst));
427
David S. Miller0e734412011-05-08 15:28:03 -0700428 if (__inet_inherit_port(sk, newsk) < 0)
429 goto put_and_exit;
Eric Dumazet9327f702009-12-04 03:46:54 +0000430 __inet_hash_nolisten(newsk, NULL);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700431
432 return newsk;
433
434exit_overflow:
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700435 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
Balazs Scheidler093d2822010-10-21 13:06:43 +0200436exit_nonewsk:
437 dst_release(dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700438exit:
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700439 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700440 return NULL;
David S. Miller0e734412011-05-08 15:28:03 -0700441put_and_exit:
Christoph Paasche337e242012-12-14 04:07:58 +0000442 inet_csk_prepare_forced_close(newsk);
443 dccp_done(newsk);
David S. Miller0e734412011-05-08 15:28:03 -0700444 goto exit;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700445}
446
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800447EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
448
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700449static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
450{
451 const struct dccp_hdr *dh = dccp_hdr(skb);
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700452 const struct iphdr *iph = ip_hdr(skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700453 struct sock *nsk;
454 struct request_sock **prev;
455 /* Find possible connection requests. */
456 struct request_sock *req = inet_csk_search_req(sk, &prev,
457 dh->dccph_sport,
458 iph->saddr, iph->daddr);
459 if (req != NULL)
460 return dccp_check_req(sk, skb, req, prev);
461
Pavel Emelyanovb9901a82008-04-13 22:30:43 -0700462 nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
Herbert Xu8f4910692006-08-09 15:47:12 -0700463 iph->saddr, dh->dccph_sport,
464 iph->daddr, dh->dccph_dport,
465 inet_iif(skb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700466 if (nsk != NULL) {
467 if (nsk->sk_state != DCCP_TIME_WAIT) {
468 bh_lock_sock(nsk);
469 return nsk;
470 }
YOSHIFUJI Hideaki9469c7b2006-10-10 19:41:46 -0700471 inet_twsk_put(inet_twsk(nsk));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700472 return NULL;
473 }
474
475 return sk;
476}
477
Pavel Emelyanovf5487392008-04-13 22:30:19 -0700478static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700479 struct sk_buff *skb)
480{
481 struct rtable *rt;
David S. Miller898f7352011-12-01 13:28:34 -0500482 const struct iphdr *iph = ip_hdr(skb);
David S. Miller9d6ec932011-03-12 01:12:47 -0500483 struct flowi4 fl4 = {
David S. Miller92101b32012-07-23 16:29:00 -0700484 .flowi4_oif = inet_iif(skb),
David S. Miller898f7352011-12-01 13:28:34 -0500485 .daddr = iph->saddr,
486 .saddr = iph->daddr,
David S. Miller9d6ec932011-03-12 01:12:47 -0500487 .flowi4_tos = RT_CONN_FLAGS(sk),
488 .flowi4_proto = sk->sk_protocol,
David S. Miller9cce96d2011-03-12 03:00:33 -0500489 .fl4_sport = dccp_hdr(skb)->dccph_dport,
490 .fl4_dport = dccp_hdr(skb)->dccph_sport,
David S. Miller1d28f422011-03-12 00:29:39 -0500491 };
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700492
David S. Miller9d6ec932011-03-12 01:12:47 -0500493 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
494 rt = ip_route_output_flow(net, &fl4, sk);
David S. Millerb23dd4f2011-03-02 14:31:35 -0800495 if (IS_ERR(rt)) {
Pavel Emelyanov7c73a6f2008-07-16 20:20:11 -0700496 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700497 return NULL;
498 }
499
Changli Gaod8d1f302010-06-10 23:31:35 -0700500 return &rt->dst;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700501}
502
Christoph Paasch1a2c6182013-03-17 08:23:34 +0000503static int dccp_v4_send_response(struct sock *sk, struct request_sock *req)
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200504{
505 int err = -1;
506 struct sk_buff *skb;
Denis V. Lunevfd80eb92008-02-29 11:43:03 -0800507 struct dst_entry *dst;
David S. Miller6bd023f2011-05-18 18:32:03 -0400508 struct flowi4 fl4;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200509
David S. Millerba3f7f02012-07-17 14:02:46 -0700510 dst = inet_csk_route_req(sk, &fl4, req);
Denis V. Lunevfd80eb92008-02-29 11:43:03 -0800511 if (dst == NULL)
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200512 goto out;
513
514 skb = dccp_make_response(sk, dst, req);
515 if (skb != NULL) {
516 const struct inet_request_sock *ireq = inet_rsk(req);
517 struct dccp_hdr *dh = dccp_hdr(skb);
518
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200519 dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
520 ireq->rmt_addr);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200521 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
522 ireq->rmt_addr,
523 ireq->opt);
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200524 err = net_xmit_eval(err);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200525 }
526
527out:
528 dst_release(dst);
529 return err;
530}
531
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800532static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700533{
534 int err;
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700535 const struct iphdr *rxiph;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700536 struct sk_buff *skb;
537 struct dst_entry *dst;
Eric Dumazetadf30902009-06-02 05:19:30 +0000538 struct net *net = dev_net(skb_dst(rxskb)->dev);
Pavel Emelyanovb76c4b22008-04-13 22:29:59 -0700539 struct sock *ctl_sk = net->dccp.v4_ctl_sk;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700540
541 /* Never send a reset in response to a reset. */
Gerrit Renkere356d372007-09-26 14:35:19 -0300542 if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700543 return;
544
Eric Dumazet511c3f92009-06-02 05:14:27 +0000545 if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700546 return;
547
Pavel Emelyanovf5487392008-04-13 22:30:19 -0700548 dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700549 if (dst == NULL)
550 return;
551
Pavel Emelyanov7b1cffa2008-04-13 22:29:37 -0700552 skb = dccp_ctl_make_reset(ctl_sk, rxskb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700553 if (skb == NULL)
554 goto out;
555
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700556 rxiph = ip_hdr(rxskb);
Gerrit Renkere356d372007-09-26 14:35:19 -0300557 dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
558 rxiph->daddr);
Eric Dumazetadf30902009-06-02 05:19:30 +0000559 skb_dst_set(skb, dst_clone(dst));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700560
Pavel Emelyanov7b1cffa2008-04-13 22:29:37 -0700561 bh_lock_sock(ctl_sk);
562 err = ip_build_and_send_pkt(skb, ctl_sk,
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700563 rxiph->daddr, rxiph->saddr, NULL);
Pavel Emelyanov7b1cffa2008-04-13 22:29:37 -0700564 bh_unlock_sock(ctl_sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700565
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200566 if (net_xmit_eval(err) == 0) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700567 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
568 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
569 }
570out:
571 dst_release(dst);
572}
573
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200574static void dccp_v4_reqsk_destructor(struct request_sock *req)
575{
Gerrit Renkerd99a7bd2008-11-04 23:56:30 -0800576 dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200577 kfree(inet_rsk(req)->opt);
578}
579
Eric Dumazetc72e1182012-04-12 22:16:05 +0000580void dccp_syn_ack_timeout(struct sock *sk, struct request_sock *req)
581{
582}
583EXPORT_SYMBOL(dccp_syn_ack_timeout);
584
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200585static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
586 .family = PF_INET,
587 .obj_size = sizeof(struct dccp_request_sock),
588 .rtx_syn_ack = dccp_v4_send_response,
589 .send_ack = dccp_reqsk_send_ack,
590 .destructor = dccp_v4_reqsk_destructor,
591 .send_reset = dccp_v4_ctl_send_reset,
Eric Dumazetc72e1182012-04-12 22:16:05 +0000592 .syn_ack_timeout = dccp_syn_ack_timeout,
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200593};
594
595int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
596{
597 struct inet_request_sock *ireq;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200598 struct request_sock *req;
599 struct dccp_request_sock *dreq;
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200600 const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200601 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200602
603 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
Eric Dumazet511c3f92009-06-02 05:14:27 +0000604 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
Gerrit Renker4a5409a2007-10-04 14:52:28 -0700605 return 0; /* discard, don't send a reset here */
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200606
607 if (dccp_bad_service_code(sk, service)) {
Gerrit Renker4a5409a2007-10-04 14:52:28 -0700608 dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200609 goto drop;
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200610 }
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200611 /*
612 * TW buckets are converted to open requests without
613 * limitations, they conserve resources and peer is
614 * evidently real one.
615 */
Gerrit Renker4a5409a2007-10-04 14:52:28 -0700616 dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200617 if (inet_csk_reqsk_queue_is_full(sk))
618 goto drop;
619
620 /*
621 * Accept backlog is full. If we have already queued enough
622 * of warm entries in syn queue, drop request. It is better than
623 * clogging syn queue with openreqs with exponentially increasing
624 * timeout.
625 */
626 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
627 goto drop;
628
Arnaldo Carvalho de Meloce4a7d02008-06-10 12:39:35 -0700629 req = inet_reqsk_alloc(&dccp_request_sock_ops);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200630 if (req == NULL)
631 goto drop;
632
Gerrit Renkerac757732008-11-04 23:55:49 -0800633 if (dccp_reqsk_init(req, dccp_sk(sk), skb))
634 goto drop_and_free;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200635
Gerrit Renker8b819412007-12-13 12:29:24 -0200636 dreq = dccp_rsk(req);
637 if (dccp_parse_options(sk, dreq, skb))
638 goto drop_and_free;
639
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200640 if (security_inet_conn_request(sk, skb, req))
641 goto drop_and_free;
642
643 ireq = inet_rsk(req);
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700644 ireq->loc_addr = ip_hdr(skb)->daddr;
645 ireq->rmt_addr = ip_hdr(skb)->saddr;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200646
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200647 /*
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200648 * Step 3: Process LISTEN state
649 *
650 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
651 *
Samuel Jerof541fb72012-02-26 18:22:02 -0700652 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200653 */
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200654 dreq->dreq_isr = dcb->dccpd_seq;
Samuel Jerof541fb72012-02-26 18:22:02 -0700655 dreq->dreq_gsr = dreq->dreq_isr;
Gerrit Renker865e9022006-11-13 13:31:50 -0200656 dreq->dreq_iss = dccp_v4_init_sequence(skb);
Samuel Jerof541fb72012-02-26 18:22:02 -0700657 dreq->dreq_gss = dreq->dreq_iss;
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200658 dreq->dreq_service = service;
659
Christoph Paasch1a2c6182013-03-17 08:23:34 +0000660 if (dccp_v4_send_response(sk, req))
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200661 goto drop_and_free;
662
663 inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
664 return 0;
665
666drop_and_free:
667 reqsk_free(req);
668drop:
669 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
Gerrit Renker3d2fe622006-11-10 12:52:36 -0200670 return -1;
671}
672
673EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
674
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700675int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
676{
677 struct dccp_hdr *dh = dccp_hdr(skb);
678
679 if (sk->sk_state == DCCP_OPEN) { /* Fast path */
680 if (dccp_rcv_established(sk, skb, dh, skb->len))
681 goto reset;
682 return 0;
683 }
684
685 /*
686 * Step 3: Process LISTEN state
Gerrit Renkerd83ca5a2006-11-10 16:29:14 -0200687 * If P.type == Request or P contains a valid Init Cookie option,
688 * (* Must scan the packet's options to check for Init
689 * Cookies. Only Init Cookies are processed here,
690 * however; other options are processed in Step 8. This
691 * scan need only be performed if the endpoint uses Init
692 * Cookies *)
693 * (* Generate a new socket and switch to that socket *)
694 * Set S := new socket for this port pair
695 * S.state = RESPOND
696 * Choose S.ISS (initial seqno) or set from Init Cookies
697 * Initialize S.GAR := S.ISS
698 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
699 * Continue with S.state == RESPOND
700 * (* A Response packet will be generated in Step 11 *)
701 * Otherwise,
702 * Generate Reset(No Connection) unless P.type == Reset
703 * Drop packet and return
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700704 *
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300705 * NOTE: the check for the packet types is done in
706 * dccp_rcv_state_process
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700707 */
708 if (sk->sk_state == DCCP_LISTEN) {
709 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
710
711 if (nsk == NULL)
712 goto discard;
713
714 if (nsk != sk) {
715 if (dccp_child_process(sk, nsk, skb))
716 goto reset;
717 return 0;
718 }
719 }
720
721 if (dccp_rcv_state_process(sk, skb, dh, skb->len))
722 goto reset;
723 return 0;
724
725reset:
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800726 dccp_v4_ctl_send_reset(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700727discard:
728 kfree_skb(skb);
729 return 0;
730}
731
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800732EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
733
Gerrit Renker09dbc382006-11-14 12:57:34 -0200734/**
735 * dccp_invalid_packet - check for malformed packets
736 * Implements RFC 4340, 8.5: Step 1: Check header basics
737 * Packets that fail these checks are ignored and do not receive Resets.
738 */
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800739int dccp_invalid_packet(struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700740{
741 const struct dccp_hdr *dh;
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200742 unsigned int cscov;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700743
744 if (skb->pkt_type != PACKET_HOST)
745 return 1;
746
Gerrit Renker09dbc382006-11-14 12:57:34 -0200747 /* If the packet is shorter than 12 bytes, drop packet and return */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700748 if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200749 DCCP_WARN("pskb_may_pull failed\n");
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700750 return 1;
751 }
752
753 dh = dccp_hdr(skb);
754
Gerrit Renker09dbc382006-11-14 12:57:34 -0200755 /* If P.type is not understood, drop packet and return */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700756 if (dh->dccph_type >= DCCP_PKT_INVALID) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200757 DCCP_WARN("invalid packet type\n");
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700758 return 1;
759 }
760
761 /*
Gerrit Renker09dbc382006-11-14 12:57:34 -0200762 * If P.Data Offset is too small for packet type, drop packet and return
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700763 */
764 if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200765 DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700766 return 1;
767 }
Gerrit Renker09dbc382006-11-14 12:57:34 -0200768 /*
769 * If P.Data Offset is too too large for packet, drop packet and return
770 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700771 if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200772 DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700773 return 1;
774 }
775
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700776 /*
777 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
778 * has short sequence numbers), drop packet and return
779 */
Wei Yongjun6079a462008-05-27 06:22:38 -0700780 if ((dh->dccph_type < DCCP_PKT_DATA ||
781 dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200782 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
783 dccp_packet_name(dh->dccph_type));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700784 return 1;
785 }
786
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200787 /*
788 * If P.CsCov is too large for the packet size, drop packet and return.
789 * This must come _before_ checksumming (not as RFC 4340 suggests).
790 */
791 cscov = dccp_csum_coverage(skb);
792 if (cscov > skb->len) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200793 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
794 dh->dccph_cscov, skb->len);
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200795 return 1;
796 }
797
798 /* If header checksum is incorrect, drop packet and return.
799 * (This step is completed in the AF-dependent functions.) */
800 skb->csum = skb_checksum(skb, 0, cscov, 0);
801
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700802 return 0;
803}
804
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800805EXPORT_SYMBOL_GPL(dccp_invalid_packet);
806
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700807/* this is called when real data arrives */
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800808static int dccp_v4_rcv(struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700809{
810 const struct dccp_hdr *dh;
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700811 const struct iphdr *iph;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700812 struct sock *sk;
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200813 int min_cov;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700814
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200815 /* Step 1: Check header basics */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700816
817 if (dccp_invalid_packet(skb))
818 goto discard_it;
819
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700820 iph = ip_hdr(skb);
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200821 /* Step 1: If header checksum is incorrect, drop packet and return */
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700822 if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
Gerrit Renker59348b12006-11-20 18:39:23 -0200823 DCCP_WARN("dropped packet with invalid checksum\n");
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800824 goto discard_it;
825 }
826
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700827 dh = dccp_hdr(skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700828
Gerrit Renkerfde20102007-10-24 10:12:09 -0200829 DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700830 DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
831
Harvey Harrison21454aa2008-10-31 00:54:56 -0700832 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700833 dccp_packet_name(dh->dccph_type),
Harvey Harrison21454aa2008-10-31 00:54:56 -0700834 &iph->saddr, ntohs(dh->dccph_sport),
835 &iph->daddr, ntohs(dh->dccph_dport),
David S. Millerf6ccf552005-08-09 20:27:14 -0700836 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700837
838 if (dccp_packet_without_ack(skb)) {
839 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
840 dccp_pr_debug_cat("\n");
841 } else {
842 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
Gerrit Renkerd23c7102006-11-10 11:46:34 -0200843 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
David S. Millerf6ccf552005-08-09 20:27:14 -0700844 DCCP_SKB_CB(skb)->dccpd_ack_seq);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700845 }
846
847 /* Step 2:
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200848 * Look up flow ID in table and get corresponding socket */
Arnaldo Carvalho de Melo9a1f27c2008-10-07 11:41:57 -0700849 sk = __inet_lookup_skb(&dccp_hashinfo, skb,
850 dh->dccph_sport, dh->dccph_dport);
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200851 /*
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700852 * Step 2:
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200853 * If no socket ...
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700854 */
855 if (sk == NULL) {
856 dccp_pr_debug("failed to look up flow ID in table and "
857 "get corresponding socket\n");
858 goto no_dccp_socket;
859 }
860
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200861 /*
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700862 * Step 2:
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200863 * ... or S.state == TIMEWAIT,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700864 * Generate Reset(No Connection) unless P.type == Reset
865 * Drop packet and return
866 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700867 if (sk->sk_state == DCCP_TIME_WAIT) {
Gerrit Renkerd23c7102006-11-10 11:46:34 -0200868 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
869 inet_twsk_put(inet_twsk(sk));
870 goto no_dccp_socket;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700871 }
872
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200873 /*
874 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200875 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
876 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200877 */
878 min_cov = dccp_sk(sk)->dccps_pcrlen;
879 if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
880 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
881 dh->dccph_cscov, min_cov);
882 /* FIXME: "Such packets SHOULD be reported using Data Dropped
883 * options (Section 11.7) with Drop Code 0, Protocol
884 * Constraints." */
885 goto discard_and_relse;
886 }
887
Arnaldo Carvalho de Melo25995ff2005-12-27 02:42:22 -0200888 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700889 goto discard_and_relse;
Patrick McHardyeb9c7eb2006-01-06 23:06:30 -0800890 nf_reset(skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700891
Arnaldo Carvalho de Melo58a5a7b2006-11-16 14:06:06 -0200892 return sk_receive_skb(sk, skb, 1);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700893
894no_dccp_socket:
895 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
896 goto discard_it;
897 /*
898 * Step 2:
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200899 * If no socket ...
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700900 * Generate Reset(No Connection) unless P.type == Reset
901 * Drop packet and return
902 */
903 if (dh->dccph_type != DCCP_PKT_RESET) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300904 DCCP_SKB_CB(skb)->dccpd_reset_code =
905 DCCP_RESET_CODE_NO_CONNECTION;
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800906 dccp_v4_ctl_send_reset(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700907 }
908
909discard_it:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700910 kfree_skb(skb);
911 return 0;
912
913discard_and_relse:
914 sock_put(sk);
915 goto discard_it;
916}
917
Stephen Hemminger3b401a82009-09-01 19:25:04 +0000918static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800919 .queue_xmit = ip_queue_xmit,
920 .send_check = dccp_v4_send_check,
921 .rebuild_header = inet_sk_rebuild_header,
922 .conn_request = dccp_v4_conn_request,
923 .syn_recv_sock = dccp_v4_request_recv_sock,
924 .net_header_len = sizeof(struct iphdr),
925 .setsockopt = ip_setsockopt,
926 .getsockopt = ip_getsockopt,
927 .addr2sockaddr = inet_csk_addr2sockaddr,
928 .sockaddr_len = sizeof(struct sockaddr_in),
Arnaldo Carvalho de Meloab1e0a12008-02-03 04:06:04 -0800929 .bind_conflict = inet_csk_bind_conflict,
Dmitry Mishin3fdadf72006-03-20 22:45:21 -0800930#ifdef CONFIG_COMPAT
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800931 .compat_setsockopt = compat_ip_setsockopt,
932 .compat_getsockopt = compat_ip_getsockopt,
Dmitry Mishin3fdadf72006-03-20 22:45:21 -0800933#endif
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800934};
935
Arnaldo Carvalho de Melo3e0fadc2006-03-20 21:23:15 -0800936static int dccp_v4_init_sock(struct sock *sk)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700937{
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -0800938 static __u8 dccp_v4_ctl_sock_initialized;
939 int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700940
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -0800941 if (err == 0) {
942 if (unlikely(!dccp_v4_ctl_sock_initialized))
943 dccp_v4_ctl_sock_initialized = 1;
Arnaldo Carvalho de Melo3e0fadc2006-03-20 21:23:15 -0800944 inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
Arnaldo Carvalho de Melo72478872006-03-20 22:00:37 -0800945 }
946
Arnaldo Carvalho de Melo3e0fadc2006-03-20 21:23:15 -0800947 return err;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700948}
949
Arnaldo Carvalho de Melo6d6ee432005-12-13 23:25:19 -0800950static struct timewait_sock_ops dccp_timewait_sock_ops = {
951 .twsk_obj_size = sizeof(struct inet_timewait_sock),
952};
953
Adrian Bunk5e0817f2006-03-20 21:58:29 -0800954static struct proto dccp_v4_prot = {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700955 .name = "DCCP",
956 .owner = THIS_MODULE,
957 .close = dccp_close,
958 .connect = dccp_v4_connect,
959 .disconnect = dccp_disconnect,
960 .ioctl = dccp_ioctl,
961 .init = dccp_v4_init_sock,
962 .setsockopt = dccp_setsockopt,
963 .getsockopt = dccp_getsockopt,
964 .sendmsg = dccp_sendmsg,
965 .recvmsg = dccp_recvmsg,
966 .backlog_rcv = dccp_v4_do_rcv,
Arnaldo Carvalho de Meloab1e0a12008-02-03 04:06:04 -0800967 .hash = inet_hash,
968 .unhash = inet_unhash,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700969 .accept = inet_csk_accept,
Arnaldo Carvalho de Meloab1e0a12008-02-03 04:06:04 -0800970 .get_port = inet_csk_get_port,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700971 .shutdown = dccp_shutdown,
Arnaldo Carvalho de Melo3e0fadc2006-03-20 21:23:15 -0800972 .destroy = dccp_destroy_sock,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700973 .orphan_count = &dccp_orphan_count,
974 .max_header = MAX_DCCP_HEADER,
975 .obj_size = sizeof(struct dccp_sock),
Eric Dumazet3ab5aee2008-11-16 19:40:17 -0800976 .slab_flags = SLAB_DESTROY_BY_RCU,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700977 .rsk_prot = &dccp_request_sock_ops,
Arnaldo Carvalho de Melo6d6ee432005-12-13 23:25:19 -0800978 .twsk_prot = &dccp_timewait_sock_ops,
Pavel Emelyanov39d8cda2008-03-22 16:50:58 -0700979 .h.hashinfo = &dccp_hashinfo,
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800980#ifdef CONFIG_COMPAT
981 .compat_setsockopt = compat_dccp_setsockopt,
982 .compat_getsockopt = compat_dccp_getsockopt,
983#endif
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700984};
Arnaldo Carvalho de Melo6d6ee432005-12-13 23:25:19 -0800985
Alexey Dobriyan32613092009-09-14 12:21:47 +0000986static const struct net_protocol dccp_v4_protocol = {
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800987 .handler = dccp_v4_rcv,
988 .err_handler = dccp_v4_err,
989 .no_policy = 1,
Pavel Emelyanovfc5f8582008-04-13 22:31:05 -0700990 .netns_ok = 1,
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800991};
992
993static const struct proto_ops inet_dccp_ops = {
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -0800994 .family = PF_INET,
995 .owner = THIS_MODULE,
996 .release = inet_release,
997 .bind = inet_bind,
998 .connect = inet_stream_connect,
999 .socketpair = sock_no_socketpair,
1000 .accept = inet_accept,
1001 .getname = inet_getname,
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001002 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -08001003 .poll = dccp_poll,
1004 .ioctl = inet_ioctl,
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001005 /* FIXME: work on inet_listen to rename it to sock_common_listen */
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -08001006 .listen = inet_dccp_listen,
1007 .shutdown = inet_shutdown,
1008 .setsockopt = sock_common_setsockopt,
1009 .getsockopt = sock_common_getsockopt,
1010 .sendmsg = inet_sendmsg,
1011 .recvmsg = sock_common_recvmsg,
1012 .mmap = sock_no_mmap,
1013 .sendpage = sock_no_sendpage,
Dmitry Mishin3fdadf72006-03-20 22:45:21 -08001014#ifdef CONFIG_COMPAT
Arnaldo Carvalho de Melo543d9cf2006-03-20 22:48:35 -08001015 .compat_setsockopt = compat_sock_common_setsockopt,
1016 .compat_getsockopt = compat_sock_common_getsockopt,
Dmitry Mishin3fdadf72006-03-20 22:45:21 -08001017#endif
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001018};
1019
1020static struct inet_protosw dccp_v4_protosw = {
1021 .type = SOCK_DCCP,
1022 .protocol = IPPROTO_DCCP,
1023 .prot = &dccp_v4_prot,
1024 .ops = &inet_dccp_ops,
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001025 .no_check = 0,
1026 .flags = INET_PROTOSW_ICSK,
1027};
1028
Alexey Dobriyan2c8c1e72010-01-17 03:35:32 +00001029static int __net_init dccp_v4_init_net(struct net *net)
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001030{
Gerrit Renkerd14a0eb2010-03-14 20:13:19 +00001031 if (dccp_hashinfo.bhash == NULL)
1032 return -ESOCKTNOSUPPORT;
Pavel Emelyanovb76c4b22008-04-13 22:29:59 -07001033
Gerrit Renkerd14a0eb2010-03-14 20:13:19 +00001034 return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
1035 SOCK_DCCP, IPPROTO_DCCP, net);
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001036}
1037
Alexey Dobriyan2c8c1e72010-01-17 03:35:32 +00001038static void __net_exit dccp_v4_exit_net(struct net *net)
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001039{
Pavel Emelyanovb76c4b22008-04-13 22:29:59 -07001040 inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001041}
1042
1043static struct pernet_operations dccp_v4_ops = {
1044 .init = dccp_v4_init_net,
1045 .exit = dccp_v4_exit_net,
1046};
1047
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001048static int __init dccp_v4_init(void)
1049{
1050 int err = proto_register(&dccp_v4_prot, 1);
1051
1052 if (err != 0)
1053 goto out;
1054
1055 err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1056 if (err != 0)
1057 goto out_proto_unregister;
1058
1059 inet_register_protosw(&dccp_v4_protosw);
1060
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001061 err = register_pernet_subsys(&dccp_v4_ops);
1062 if (err)
1063 goto out_destroy_ctl_sock;
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001064out:
1065 return err;
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001066out_destroy_ctl_sock:
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001067 inet_unregister_protosw(&dccp_v4_protosw);
1068 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1069out_proto_unregister:
1070 proto_unregister(&dccp_v4_prot);
1071 goto out;
1072}
1073
1074static void __exit dccp_v4_exit(void)
1075{
Pavel Emelyanov72a2d612008-04-13 22:29:13 -07001076 unregister_pernet_subsys(&dccp_v4_ops);
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001077 inet_unregister_protosw(&dccp_v4_protosw);
1078 inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
1079 proto_unregister(&dccp_v4_prot);
1080}
1081
1082module_init(dccp_v4_init);
1083module_exit(dccp_v4_exit);
1084
1085/*
1086 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1087 * values directly, Also cover the case where the protocol is not specified,
1088 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1089 */
Jean Delvare7131c6c2007-10-21 16:45:03 -07001090MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
1091MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -08001092MODULE_LICENSE("GPL");
1093MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1094MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");