4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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.
13 #include <linux/dccp.h>
14 #include <linux/icmp.h>
15 #include <linux/module.h>
16 #include <linux/skbuff.h>
17 #include <linux/random.h>
20 #include <net/inet_common.h>
21 #include <net/inet_hashtables.h>
22 #include <net/inet_sock.h>
23 #include <net/protocol.h>
25 #include <net/timewait_sock.h>
26 #include <net/tcp_states.h>
35 * This is the global socket data structure used for responding to
36 * the Out-of-the-blue (OOTB) packets. A control sock will be created
37 * for this socket at the initialization time.
39 static struct socket
*dccp_v4_ctl_socket
;
41 static int dccp_v4_get_port(struct sock
*sk
, const unsigned short snum
)
43 return inet_csk_get_port(&dccp_hashinfo
, sk
, snum
,
44 inet_csk_bind_conflict
);
47 int dccp_v4_connect(struct sock
*sk
, struct sockaddr
*uaddr
, int addr_len
)
49 struct inet_sock
*inet
= inet_sk(sk
);
50 struct dccp_sock
*dp
= dccp_sk(sk
);
51 const struct sockaddr_in
*usin
= (struct sockaddr_in
*)uaddr
;
53 __be32 daddr
, nexthop
;
57 dp
->dccps_role
= DCCP_ROLE_CLIENT
;
59 if (addr_len
< sizeof(struct sockaddr_in
))
62 if (usin
->sin_family
!= AF_INET
)
65 nexthop
= daddr
= usin
->sin_addr
.s_addr
;
66 if (inet
->opt
!= NULL
&& inet
->opt
->srr
) {
69 nexthop
= inet
->opt
->faddr
;
72 tmp
= ip_route_connect(&rt
, nexthop
, inet
->saddr
,
73 RT_CONN_FLAGS(sk
), sk
->sk_bound_dev_if
,
75 inet
->sport
, usin
->sin_port
, sk
);
79 if (rt
->rt_flags
& (RTCF_MULTICAST
| RTCF_BROADCAST
)) {
84 if (inet
->opt
== NULL
|| !inet
->opt
->srr
)
88 inet
->saddr
= rt
->rt_src
;
89 inet
->rcv_saddr
= inet
->saddr
;
91 inet
->dport
= usin
->sin_port
;
94 inet_csk(sk
)->icsk_ext_hdr_len
= 0;
95 if (inet
->opt
!= NULL
)
96 inet_csk(sk
)->icsk_ext_hdr_len
= inet
->opt
->optlen
;
98 * Socket identity is still unknown (sport may be zero).
99 * However we set state to DCCP_REQUESTING and not releasing socket
100 * lock select source port, enter ourselves into the hash tables and
101 * complete initialization after this.
103 dccp_set_state(sk
, DCCP_REQUESTING
);
104 err
= inet_hash_connect(&dccp_death_row
, sk
);
108 err
= ip_route_newports(&rt
, IPPROTO_DCCP
, inet
->sport
, inet
->dport
,
113 /* OK, now commit destination to socket. */
114 sk_setup_caps(sk
, &rt
->u
.dst
);
117 dp
->dccps_iss
= secure_dccp_sequence_number(inet
->saddr
,
121 dccp_update_gss(sk
, dp
->dccps_iss
);
123 inet
->id
= dp
->dccps_iss
^ jiffies
;
125 err
= dccp_connect(sk
);
133 * This unhashes the socket and releases the local port, if necessary.
135 dccp_set_state(sk
, DCCP_CLOSED
);
137 sk
->sk_route_caps
= 0;
142 EXPORT_SYMBOL_GPL(dccp_v4_connect
);
145 * This routine does path mtu discovery as defined in RFC1191.
147 static inline void dccp_do_pmtu_discovery(struct sock
*sk
,
148 const struct iphdr
*iph
,
151 struct dst_entry
*dst
;
152 const struct inet_sock
*inet
= inet_sk(sk
);
153 const struct dccp_sock
*dp
= dccp_sk(sk
);
155 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
156 * send out by Linux are always < 576bytes so they should go through
159 if (sk
->sk_state
== DCCP_LISTEN
)
162 /* We don't check in the destentry if pmtu discovery is forbidden
163 * on this route. We just assume that no packet_to_big packets
164 * are send back when pmtu discovery is not active.
165 * There is a small race when the user changes this flag in the
166 * route, but I think that's acceptable.
168 if ((dst
= __sk_dst_check(sk
, 0)) == NULL
)
171 dst
->ops
->update_pmtu(dst
, mtu
);
173 /* Something is about to be wrong... Remember soft error
174 * for the case, if this connection will not able to recover.
176 if (mtu
< dst_mtu(dst
) && ip_dont_fragment(sk
, dst
))
177 sk
->sk_err_soft
= EMSGSIZE
;
181 if (inet
->pmtudisc
!= IP_PMTUDISC_DONT
&&
182 inet_csk(sk
)->icsk_pmtu_cookie
> mtu
) {
183 dccp_sync_mss(sk
, mtu
);
186 * From RFC 4340, sec. 14.1:
188 * DCCP-Sync packets are the best choice for upward
189 * probing, since DCCP-Sync probes do not risk application
192 dccp_send_sync(sk
, dp
->dccps_gsr
, DCCP_PKT_SYNC
);
193 } /* else let the usual retransmit timer handle it */
197 * This routine is called by the ICMP module when it gets some sort of error
198 * condition. If err < 0 then the socket should be closed and the error
199 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
200 * After adjustment header points to the first 8 bytes of the tcp header. We
201 * need to find the appropriate port.
203 * The locking strategy used here is very "optimistic". When someone else
204 * accesses the socket the ICMP is just dropped and for some paths there is no
205 * check at all. A more general error queue to queue errors for later handling
206 * is probably better.
208 static void dccp_v4_err(struct sk_buff
*skb
, u32 info
)
210 const struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
211 const struct dccp_hdr
*dh
= (struct dccp_hdr
*)(skb
->data
+
213 struct dccp_sock
*dp
;
214 struct inet_sock
*inet
;
215 const int type
= skb
->h
.icmph
->type
;
216 const int code
= skb
->h
.icmph
->code
;
221 if (skb
->len
< (iph
->ihl
<< 2) + 8) {
222 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
226 sk
= inet_lookup(&dccp_hashinfo
, iph
->daddr
, dh
->dccph_dport
,
227 iph
->saddr
, dh
->dccph_sport
, inet_iif(skb
));
229 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
233 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
234 inet_twsk_put(inet_twsk(sk
));
239 /* If too many ICMPs get dropped on busy
240 * servers this needs to be solved differently.
242 if (sock_owned_by_user(sk
))
243 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS
);
245 if (sk
->sk_state
== DCCP_CLOSED
)
249 seq
= dccp_hdr_seq(skb
);
250 if (sk
->sk_state
!= DCCP_LISTEN
&&
251 !between48(seq
, dp
->dccps_swl
, dp
->dccps_swh
)) {
252 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS
);
257 case ICMP_SOURCE_QUENCH
:
258 /* Just silently ignore these. */
260 case ICMP_PARAMETERPROB
:
263 case ICMP_DEST_UNREACH
:
264 if (code
> NR_ICMP_UNREACH
)
267 if (code
== ICMP_FRAG_NEEDED
) { /* PMTU discovery (RFC1191) */
268 if (!sock_owned_by_user(sk
))
269 dccp_do_pmtu_discovery(sk
, iph
, info
);
273 err
= icmp_err_convert
[code
].errno
;
275 case ICMP_TIME_EXCEEDED
:
282 switch (sk
->sk_state
) {
283 struct request_sock
*req
, **prev
;
285 if (sock_owned_by_user(sk
))
287 req
= inet_csk_search_req(sk
, &prev
, dh
->dccph_dport
,
288 iph
->daddr
, iph
->saddr
);
293 * ICMPs are not backlogged, hence we cannot get an established
298 if (seq
!= dccp_rsk(req
)->dreq_iss
) {
299 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS
);
303 * Still in RESPOND, just remove it silently.
304 * There is no good way to pass the error to the newly
305 * created socket, and POSIX does not want network
306 * errors returned from accept().
308 inet_csk_reqsk_queue_drop(sk
, req
, prev
);
311 case DCCP_REQUESTING
:
313 if (!sock_owned_by_user(sk
)) {
314 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
317 sk
->sk_error_report(sk
);
321 sk
->sk_err_soft
= err
;
325 /* If we've already connected we will keep trying
326 * until we time out, or the user gives up.
328 * rfc1122 4.2.3.9 allows to consider as hard errors
329 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
330 * but it is obsoleted by pmtu discovery).
332 * Note, that in modern internet, where routing is unreliable
333 * and in each dark corner broken firewalls sit, sending random
334 * errors ordered by their masters even this two messages finally lose
335 * their original sense (even Linux sends invalid PORT_UNREACHs)
337 * Now we are in compliance with RFCs.
342 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
344 sk
->sk_error_report(sk
);
345 } else /* Only an error on timeout */
346 sk
->sk_err_soft
= err
;
352 static inline u16
dccp_v4_csum_finish(struct sk_buff
*skb
,
353 __be32 src
, __be32 dst
)
355 return csum_tcpudp_magic(src
, dst
, skb
->len
, IPPROTO_DCCP
, skb
->csum
);
358 void dccp_v4_send_check(struct sock
*sk
, int unused
, struct sk_buff
*skb
)
360 const struct inet_sock
*inet
= inet_sk(sk
);
361 struct dccp_hdr
*dh
= dccp_hdr(skb
);
363 dccp_csum_outgoing(skb
);
364 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, inet
->saddr
, inet
->daddr
);
367 EXPORT_SYMBOL_GPL(dccp_v4_send_check
);
369 static inline u64
dccp_v4_init_sequence(const struct sock
*sk
,
370 const struct sk_buff
*skb
)
372 return secure_dccp_sequence_number(skb
->nh
.iph
->daddr
,
374 dccp_hdr(skb
)->dccph_dport
,
375 dccp_hdr(skb
)->dccph_sport
);
379 * The three way handshake has completed - we got a valid ACK or DATAACK -
380 * now create the new socket.
382 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
384 struct sock
*dccp_v4_request_recv_sock(struct sock
*sk
, struct sk_buff
*skb
,
385 struct request_sock
*req
,
386 struct dst_entry
*dst
)
388 struct inet_request_sock
*ireq
;
389 struct inet_sock
*newinet
;
390 struct dccp_sock
*newdp
;
393 if (sk_acceptq_is_full(sk
))
396 if (dst
== NULL
&& (dst
= inet_csk_route_req(sk
, req
)) == NULL
)
399 newsk
= dccp_create_openreq_child(sk
, req
, skb
);
403 sk_setup_caps(newsk
, dst
);
405 newdp
= dccp_sk(newsk
);
406 newinet
= inet_sk(newsk
);
407 ireq
= inet_rsk(req
);
408 newinet
->daddr
= ireq
->rmt_addr
;
409 newinet
->rcv_saddr
= ireq
->loc_addr
;
410 newinet
->saddr
= ireq
->loc_addr
;
411 newinet
->opt
= ireq
->opt
;
413 newinet
->mc_index
= inet_iif(skb
);
414 newinet
->mc_ttl
= skb
->nh
.iph
->ttl
;
415 newinet
->id
= jiffies
;
417 dccp_sync_mss(newsk
, dst_mtu(dst
));
419 __inet_hash(&dccp_hashinfo
, newsk
, 0);
420 __inet_inherit_port(&dccp_hashinfo
, sk
, newsk
);
425 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS
);
427 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS
);
432 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock
);
434 static struct sock
*dccp_v4_hnd_req(struct sock
*sk
, struct sk_buff
*skb
)
436 const struct dccp_hdr
*dh
= dccp_hdr(skb
);
437 const struct iphdr
*iph
= skb
->nh
.iph
;
439 struct request_sock
**prev
;
440 /* Find possible connection requests. */
441 struct request_sock
*req
= inet_csk_search_req(sk
, &prev
,
443 iph
->saddr
, iph
->daddr
);
445 return dccp_check_req(sk
, skb
, req
, prev
);
447 nsk
= inet_lookup_established(&dccp_hashinfo
,
448 iph
->saddr
, dh
->dccph_sport
,
449 iph
->daddr
, dh
->dccph_dport
,
452 if (nsk
->sk_state
!= DCCP_TIME_WAIT
) {
456 inet_twsk_put(inet_twsk(nsk
));
463 static struct dst_entry
* dccp_v4_route_skb(struct sock
*sk
,
467 struct flowi fl
= { .oif
= ((struct rtable
*)skb
->dst
)->rt_iif
,
469 { .daddr
= skb
->nh
.iph
->saddr
,
470 .saddr
= skb
->nh
.iph
->daddr
,
471 .tos
= RT_CONN_FLAGS(sk
) } },
472 .proto
= sk
->sk_protocol
,
474 { .sport
= dccp_hdr(skb
)->dccph_dport
,
475 .dport
= dccp_hdr(skb
)->dccph_sport
}
479 security_skb_classify_flow(skb
, &fl
);
480 if (ip_route_output_flow(&rt
, &fl
, sk
, 0)) {
481 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES
);
488 static int dccp_v4_send_response(struct sock
*sk
, struct request_sock
*req
,
489 struct dst_entry
*dst
)
494 /* First, grab a route. */
496 if (dst
== NULL
&& (dst
= inet_csk_route_req(sk
, req
)) == NULL
)
499 skb
= dccp_make_response(sk
, dst
, req
);
501 const struct inet_request_sock
*ireq
= inet_rsk(req
);
502 struct dccp_hdr
*dh
= dccp_hdr(skb
);
504 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, ireq
->loc_addr
,
506 memset(&(IPCB(skb
)->opt
), 0, sizeof(IPCB(skb
)->opt
));
507 err
= ip_build_and_send_pkt(skb
, sk
, ireq
->loc_addr
,
510 if (err
== NET_XMIT_CN
)
519 static void dccp_v4_ctl_send_reset(struct sk_buff
*rxskb
)
522 struct dccp_hdr
*rxdh
= dccp_hdr(rxskb
), *dh
;
523 const int dccp_hdr_reset_len
= sizeof(struct dccp_hdr
) +
524 sizeof(struct dccp_hdr_ext
) +
525 sizeof(struct dccp_hdr_reset
);
527 struct dst_entry
*dst
;
530 /* Never send a reset in response to a reset. */
531 if (rxdh
->dccph_type
== DCCP_PKT_RESET
)
534 if (((struct rtable
*)rxskb
->dst
)->rt_type
!= RTN_LOCAL
)
537 dst
= dccp_v4_route_skb(dccp_v4_ctl_socket
->sk
, rxskb
);
541 skb
= alloc_skb(dccp_v4_ctl_socket
->sk
->sk_prot
->max_header
,
546 /* Reserve space for headers. */
547 skb_reserve(skb
, dccp_v4_ctl_socket
->sk
->sk_prot
->max_header
);
548 skb
->dst
= dst_clone(dst
);
550 dh
= dccp_zeroed_hdr(skb
, dccp_hdr_reset_len
);
552 /* Build DCCP header and checksum it. */
553 dh
->dccph_type
= DCCP_PKT_RESET
;
554 dh
->dccph_sport
= rxdh
->dccph_dport
;
555 dh
->dccph_dport
= rxdh
->dccph_sport
;
556 dh
->dccph_doff
= dccp_hdr_reset_len
/ 4;
558 dccp_hdr_reset(skb
)->dccph_reset_code
=
559 DCCP_SKB_CB(rxskb
)->dccpd_reset_code
;
561 /* See "8.3.1. Abnormal Termination" in RFC 4340 */
563 if (DCCP_SKB_CB(rxskb
)->dccpd_ack_seq
!= DCCP_PKT_WITHOUT_ACK_SEQ
)
564 dccp_set_seqno(&seqno
, DCCP_SKB_CB(rxskb
)->dccpd_ack_seq
+ 1);
566 dccp_hdr_set_seq(dh
, seqno
);
567 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb
),
568 DCCP_SKB_CB(rxskb
)->dccpd_seq
);
570 dccp_csum_outgoing(skb
);
571 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, rxskb
->nh
.iph
->saddr
,
572 rxskb
->nh
.iph
->daddr
);
574 bh_lock_sock(dccp_v4_ctl_socket
->sk
);
575 err
= ip_build_and_send_pkt(skb
, dccp_v4_ctl_socket
->sk
,
576 rxskb
->nh
.iph
->daddr
,
577 rxskb
->nh
.iph
->saddr
, NULL
);
578 bh_unlock_sock(dccp_v4_ctl_socket
->sk
);
580 if (err
== NET_XMIT_CN
|| err
== 0) {
581 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS
);
582 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS
);
588 static void dccp_v4_reqsk_destructor(struct request_sock
*req
)
590 kfree(inet_rsk(req
)->opt
);
593 static struct request_sock_ops dccp_request_sock_ops __read_mostly
= {
595 .obj_size
= sizeof(struct dccp_request_sock
),
596 .rtx_syn_ack
= dccp_v4_send_response
,
597 .send_ack
= dccp_reqsk_send_ack
,
598 .destructor
= dccp_v4_reqsk_destructor
,
599 .send_reset
= dccp_v4_ctl_send_reset
,
602 int dccp_v4_conn_request(struct sock
*sk
, struct sk_buff
*skb
)
604 struct inet_request_sock
*ireq
;
605 struct request_sock
*req
;
606 struct dccp_request_sock
*dreq
;
607 const __be32 service
= dccp_hdr_request(skb
)->dccph_req_service
;
608 struct dccp_skb_cb
*dcb
= DCCP_SKB_CB(skb
);
609 __u8 reset_code
= DCCP_RESET_CODE_TOO_BUSY
;
611 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
612 if (((struct rtable
*)skb
->dst
)->rt_flags
&
613 (RTCF_BROADCAST
| RTCF_MULTICAST
)) {
614 reset_code
= DCCP_RESET_CODE_NO_CONNECTION
;
618 if (dccp_bad_service_code(sk
, service
)) {
619 reset_code
= DCCP_RESET_CODE_BAD_SERVICE_CODE
;
623 * TW buckets are converted to open requests without
624 * limitations, they conserve resources and peer is
625 * evidently real one.
627 if (inet_csk_reqsk_queue_is_full(sk
))
631 * Accept backlog is full. If we have already queued enough
632 * of warm entries in syn queue, drop request. It is better than
633 * clogging syn queue with openreqs with exponentially increasing
636 if (sk_acceptq_is_full(sk
) && inet_csk_reqsk_queue_young(sk
) > 1)
639 req
= reqsk_alloc(&dccp_request_sock_ops
);
643 if (dccp_parse_options(sk
, skb
))
646 dccp_reqsk_init(req
, skb
);
648 if (security_inet_conn_request(sk
, skb
, req
))
651 ireq
= inet_rsk(req
);
652 ireq
->loc_addr
= skb
->nh
.iph
->daddr
;
653 ireq
->rmt_addr
= skb
->nh
.iph
->saddr
;
654 req
->rcv_wnd
= dccp_feat_default_sequence_window
;
658 * Step 3: Process LISTEN state
660 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
662 * In fact we defer setting S.GSR, S.SWL, S.SWH to
663 * dccp_create_openreq_child.
665 dreq
= dccp_rsk(req
);
666 dreq
->dreq_isr
= dcb
->dccpd_seq
;
667 dreq
->dreq_iss
= dccp_v4_init_sequence(sk
, skb
);
668 dreq
->dreq_service
= service
;
670 if (dccp_v4_send_response(sk
, req
, NULL
))
673 inet_csk_reqsk_queue_hash_add(sk
, req
, DCCP_TIMEOUT_INIT
);
679 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
680 dcb
->dccpd_reset_code
= reset_code
;
684 EXPORT_SYMBOL_GPL(dccp_v4_conn_request
);
686 int dccp_v4_do_rcv(struct sock
*sk
, struct sk_buff
*skb
)
688 struct dccp_hdr
*dh
= dccp_hdr(skb
);
690 if (sk
->sk_state
== DCCP_OPEN
) { /* Fast path */
691 if (dccp_rcv_established(sk
, skb
, dh
, skb
->len
))
697 * Step 3: Process LISTEN state
698 * If P.type == Request or P contains a valid Init Cookie option,
699 * (* Must scan the packet's options to check for Init
700 * Cookies. Only Init Cookies are processed here,
701 * however; other options are processed in Step 8. This
702 * scan need only be performed if the endpoint uses Init
704 * (* Generate a new socket and switch to that socket *)
705 * Set S := new socket for this port pair
707 * Choose S.ISS (initial seqno) or set from Init Cookies
708 * Initialize S.GAR := S.ISS
709 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
710 * Continue with S.state == RESPOND
711 * (* A Response packet will be generated in Step 11 *)
713 * Generate Reset(No Connection) unless P.type == Reset
714 * Drop packet and return
716 * NOTE: the check for the packet types is done in
717 * dccp_rcv_state_process
719 if (sk
->sk_state
== DCCP_LISTEN
) {
720 struct sock
*nsk
= dccp_v4_hnd_req(sk
, skb
);
726 if (dccp_child_process(sk
, nsk
, skb
))
732 if (dccp_rcv_state_process(sk
, skb
, dh
, skb
->len
))
737 dccp_v4_ctl_send_reset(skb
);
743 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv
);
745 int dccp_invalid_packet(struct sk_buff
*skb
)
747 const struct dccp_hdr
*dh
;
750 if (skb
->pkt_type
!= PACKET_HOST
)
753 if (!pskb_may_pull(skb
, sizeof(struct dccp_hdr
))) {
754 LIMIT_NETDEBUG(KERN_WARNING
"DCCP: pskb_may_pull failed\n");
760 /* If the packet type is not understood, drop packet and return */
761 if (dh
->dccph_type
>= DCCP_PKT_INVALID
) {
762 LIMIT_NETDEBUG(KERN_WARNING
"DCCP: invalid packet type\n");
767 * If P.Data Offset is too small for packet type, or too large for
768 * packet, drop packet and return
770 if (dh
->dccph_doff
< dccp_hdr_len(skb
) / sizeof(u32
)) {
771 LIMIT_NETDEBUG(KERN_WARNING
"DCCP: P.Data Offset(%u) "
777 if (!pskb_may_pull(skb
, dh
->dccph_doff
* sizeof(u32
))) {
778 LIMIT_NETDEBUG(KERN_WARNING
"DCCP: P.Data Offset(%u) "
787 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
788 * has short sequence numbers), drop packet and return
790 if (dh
->dccph_x
== 0 &&
791 dh
->dccph_type
!= DCCP_PKT_DATA
&&
792 dh
->dccph_type
!= DCCP_PKT_ACK
&&
793 dh
->dccph_type
!= DCCP_PKT_DATAACK
) {
794 LIMIT_NETDEBUG(KERN_WARNING
"DCCP: P.type (%s) not Data, Ack "
795 "nor DataAck and P.X == 0\n",
796 dccp_packet_name(dh
->dccph_type
));
801 * If P.CsCov is too large for the packet size, drop packet and return.
802 * This must come _before_ checksumming (not as RFC 4340 suggests).
804 cscov
= dccp_csum_coverage(skb
);
805 if (cscov
> skb
->len
) {
806 LIMIT_NETDEBUG(KERN_WARNING
807 "DCCP: P.CsCov %u exceeds packet length %d\n",
808 dh
->dccph_cscov
, skb
->len
);
812 /* If header checksum is incorrect, drop packet and return.
813 * (This step is completed in the AF-dependent functions.) */
814 skb
->csum
= skb_checksum(skb
, 0, cscov
, 0);
819 EXPORT_SYMBOL_GPL(dccp_invalid_packet
);
821 /* this is called when real data arrives */
822 static int dccp_v4_rcv(struct sk_buff
*skb
)
824 const struct dccp_hdr
*dh
;
828 /* Step 1: Check header basics */
830 if (dccp_invalid_packet(skb
))
833 /* Step 1: If header checksum is incorrect, drop packet and return */
834 if (dccp_v4_csum_finish(skb
, skb
->nh
.iph
->saddr
, skb
->nh
.iph
->daddr
)) {
835 LIMIT_NETDEBUG(KERN_WARNING
836 "%s: dropped packet with invalid checksum\n",
843 DCCP_SKB_CB(skb
)->dccpd_seq
= dccp_hdr_seq(skb
);
844 DCCP_SKB_CB(skb
)->dccpd_type
= dh
->dccph_type
;
846 dccp_pr_debug("%8.8s "
847 "src=%u.%u.%u.%u@%-5d "
848 "dst=%u.%u.%u.%u@%-5d seq=%llu",
849 dccp_packet_name(dh
->dccph_type
),
850 NIPQUAD(skb
->nh
.iph
->saddr
), ntohs(dh
->dccph_sport
),
851 NIPQUAD(skb
->nh
.iph
->daddr
), ntohs(dh
->dccph_dport
),
852 (unsigned long long) DCCP_SKB_CB(skb
)->dccpd_seq
);
854 if (dccp_packet_without_ack(skb
)) {
855 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= DCCP_PKT_WITHOUT_ACK_SEQ
;
856 dccp_pr_debug_cat("\n");
858 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= dccp_hdr_ack_seq(skb
);
859 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
860 DCCP_SKB_CB(skb
)->dccpd_ack_seq
);
864 * Look up flow ID in table and get corresponding socket */
865 sk
= __inet_lookup(&dccp_hashinfo
,
866 skb
->nh
.iph
->saddr
, dh
->dccph_sport
,
867 skb
->nh
.iph
->daddr
, dh
->dccph_dport
,
875 dccp_pr_debug("failed to look up flow ID in table and "
876 "get corresponding socket\n");
882 * ... or S.state == TIMEWAIT,
883 * Generate Reset(No Connection) unless P.type == Reset
884 * Drop packet and return
886 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
887 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
888 inet_twsk_put(inet_twsk(sk
));
893 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
894 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
895 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
897 min_cov
= dccp_sk(sk
)->dccps_pcrlen
;
898 if (dh
->dccph_cscov
&& (min_cov
== 0 || dh
->dccph_cscov
< min_cov
)) {
899 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
900 dh
->dccph_cscov
, min_cov
);
901 /* FIXME: "Such packets SHOULD be reported using Data Dropped
902 * options (Section 11.7) with Drop Code 0, Protocol
904 goto discard_and_relse
;
907 if (!xfrm4_policy_check(sk
, XFRM_POLICY_IN
, skb
))
908 goto discard_and_relse
;
911 return sk_receive_skb(sk
, skb
);
914 if (!xfrm4_policy_check(NULL
, XFRM_POLICY_IN
, skb
))
919 * Generate Reset(No Connection) unless P.type == Reset
920 * Drop packet and return
922 if (dh
->dccph_type
!= DCCP_PKT_RESET
) {
923 DCCP_SKB_CB(skb
)->dccpd_reset_code
=
924 DCCP_RESET_CODE_NO_CONNECTION
;
925 dccp_v4_ctl_send_reset(skb
);
937 static struct inet_connection_sock_af_ops dccp_ipv4_af_ops
= {
938 .queue_xmit
= ip_queue_xmit
,
939 .send_check
= dccp_v4_send_check
,
940 .rebuild_header
= inet_sk_rebuild_header
,
941 .conn_request
= dccp_v4_conn_request
,
942 .syn_recv_sock
= dccp_v4_request_recv_sock
,
943 .net_header_len
= sizeof(struct iphdr
),
944 .setsockopt
= ip_setsockopt
,
945 .getsockopt
= ip_getsockopt
,
946 .addr2sockaddr
= inet_csk_addr2sockaddr
,
947 .sockaddr_len
= sizeof(struct sockaddr_in
),
949 .compat_setsockopt
= compat_ip_setsockopt
,
950 .compat_getsockopt
= compat_ip_getsockopt
,
954 static int dccp_v4_init_sock(struct sock
*sk
)
956 static __u8 dccp_v4_ctl_sock_initialized
;
957 int err
= dccp_init_sock(sk
, dccp_v4_ctl_sock_initialized
);
960 if (unlikely(!dccp_v4_ctl_sock_initialized
))
961 dccp_v4_ctl_sock_initialized
= 1;
962 inet_csk(sk
)->icsk_af_ops
= &dccp_ipv4_af_ops
;
968 static struct timewait_sock_ops dccp_timewait_sock_ops
= {
969 .twsk_obj_size
= sizeof(struct inet_timewait_sock
),
972 static struct proto dccp_v4_prot
= {
974 .owner
= THIS_MODULE
,
976 .connect
= dccp_v4_connect
,
977 .disconnect
= dccp_disconnect
,
979 .init
= dccp_v4_init_sock
,
980 .setsockopt
= dccp_setsockopt
,
981 .getsockopt
= dccp_getsockopt
,
982 .sendmsg
= dccp_sendmsg
,
983 .recvmsg
= dccp_recvmsg
,
984 .backlog_rcv
= dccp_v4_do_rcv
,
986 .unhash
= dccp_unhash
,
987 .accept
= inet_csk_accept
,
988 .get_port
= dccp_v4_get_port
,
989 .shutdown
= dccp_shutdown
,
990 .destroy
= dccp_destroy_sock
,
991 .orphan_count
= &dccp_orphan_count
,
992 .max_header
= MAX_DCCP_HEADER
,
993 .obj_size
= sizeof(struct dccp_sock
),
994 .rsk_prot
= &dccp_request_sock_ops
,
995 .twsk_prot
= &dccp_timewait_sock_ops
,
997 .compat_setsockopt
= compat_dccp_setsockopt
,
998 .compat_getsockopt
= compat_dccp_getsockopt
,
1002 static struct net_protocol dccp_v4_protocol
= {
1003 .handler
= dccp_v4_rcv
,
1004 .err_handler
= dccp_v4_err
,
1008 static const struct proto_ops inet_dccp_ops
= {
1010 .owner
= THIS_MODULE
,
1011 .release
= inet_release
,
1013 .connect
= inet_stream_connect
,
1014 .socketpair
= sock_no_socketpair
,
1015 .accept
= inet_accept
,
1016 .getname
= inet_getname
,
1017 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
1019 .ioctl
= inet_ioctl
,
1020 /* FIXME: work on inet_listen to rename it to sock_common_listen */
1021 .listen
= inet_dccp_listen
,
1022 .shutdown
= inet_shutdown
,
1023 .setsockopt
= sock_common_setsockopt
,
1024 .getsockopt
= sock_common_getsockopt
,
1025 .sendmsg
= inet_sendmsg
,
1026 .recvmsg
= sock_common_recvmsg
,
1027 .mmap
= sock_no_mmap
,
1028 .sendpage
= sock_no_sendpage
,
1029 #ifdef CONFIG_COMPAT
1030 .compat_setsockopt
= compat_sock_common_setsockopt
,
1031 .compat_getsockopt
= compat_sock_common_getsockopt
,
1035 static struct inet_protosw dccp_v4_protosw
= {
1037 .protocol
= IPPROTO_DCCP
,
1038 .prot
= &dccp_v4_prot
,
1039 .ops
= &inet_dccp_ops
,
1042 .flags
= INET_PROTOSW_ICSK
,
1045 static int __init
dccp_v4_init(void)
1047 int err
= proto_register(&dccp_v4_prot
, 1);
1052 err
= inet_add_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1054 goto out_proto_unregister
;
1056 inet_register_protosw(&dccp_v4_protosw
);
1058 err
= inet_csk_ctl_sock_create(&dccp_v4_ctl_socket
, PF_INET
,
1059 SOCK_DCCP
, IPPROTO_DCCP
);
1061 goto out_unregister_protosw
;
1064 out_unregister_protosw
:
1065 inet_unregister_protosw(&dccp_v4_protosw
);
1066 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1067 out_proto_unregister
:
1068 proto_unregister(&dccp_v4_prot
);
1072 static void __exit
dccp_v4_exit(void)
1074 inet_unregister_protosw(&dccp_v4_protosw
);
1075 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1076 proto_unregister(&dccp_v4_prot
);
1079 module_init(dccp_v4_init
);
1080 module_exit(dccp_v4_exit
);
1083 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1084 * values directly, Also cover the case where the protocol is not specified,
1085 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1087 MODULE_ALIAS("net-pf-" __stringify(PF_INET
) "-proto-33-type-6");
1088 MODULE_ALIAS("net-pf-" __stringify(PF_INET
) "-proto-0-type-6");
1089 MODULE_LICENSE("GPL");
1090 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1091 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");