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/slab.h>
16 #include <linux/module.h>
17 #include <linux/skbuff.h>
18 #include <linux/random.h>
21 #include <net/inet_common.h>
22 #include <net/inet_hashtables.h>
23 #include <net/inet_sock.h>
24 #include <net/protocol.h>
26 #include <net/timewait_sock.h>
27 #include <net/tcp_states.h>
29 #include <net/secure_seq.h>
37 * The per-net dccp.v4_ctl_sk socket is used for responding to
38 * the Out-of-the-blue (OOTB) packets. A control sock will be created
39 * for this socket at the initialization time.
42 int dccp_v4_connect(struct sock
*sk
, struct sockaddr
*uaddr
, int addr_len
)
44 const struct sockaddr_in
*usin
= (struct sockaddr_in
*)uaddr
;
45 struct inet_sock
*inet
= inet_sk(sk
);
46 struct dccp_sock
*dp
= dccp_sk(sk
);
47 __be16 orig_sport
, orig_dport
;
48 __be32 daddr
, nexthop
;
52 struct ip_options_rcu
*inet_opt
;
54 dp
->dccps_role
= DCCP_ROLE_CLIENT
;
56 if (addr_len
< sizeof(struct sockaddr_in
))
59 if (usin
->sin_family
!= AF_INET
)
62 nexthop
= daddr
= usin
->sin_addr
.s_addr
;
64 inet_opt
= rcu_dereference_protected(inet
->inet_opt
,
65 sock_owned_by_user(sk
));
66 if (inet_opt
!= NULL
&& inet_opt
->opt
.srr
) {
69 nexthop
= inet_opt
->opt
.faddr
;
72 orig_sport
= inet
->inet_sport
;
73 orig_dport
= usin
->sin_port
;
74 fl4
= &inet
->cork
.fl
.u
.ip4
;
75 rt
= ip_route_connect(fl4
, nexthop
, inet
->inet_saddr
,
76 RT_CONN_FLAGS(sk
), sk
->sk_bound_dev_if
,
78 orig_sport
, orig_dport
, sk
);
82 if (rt
->rt_flags
& (RTCF_MULTICAST
| RTCF_BROADCAST
)) {
87 if (inet_opt
== NULL
|| !inet_opt
->opt
.srr
)
90 if (inet
->inet_saddr
== 0)
91 inet
->inet_saddr
= fl4
->saddr
;
92 sk_rcv_saddr_set(sk
, inet
->inet_saddr
);
93 inet
->inet_dport
= usin
->sin_port
;
94 sk_daddr_set(sk
, daddr
);
96 inet_csk(sk
)->icsk_ext_hdr_len
= 0;
98 inet_csk(sk
)->icsk_ext_hdr_len
= inet_opt
->opt
.optlen
;
100 * Socket identity is still unknown (sport may be zero).
101 * However we set state to DCCP_REQUESTING and not releasing socket
102 * lock select source port, enter ourselves into the hash tables and
103 * complete initialization after this.
105 dccp_set_state(sk
, DCCP_REQUESTING
);
106 err
= inet_hash_connect(&dccp_death_row
, sk
);
110 rt
= ip_route_newports(fl4
, rt
, orig_sport
, orig_dport
,
111 inet
->inet_sport
, inet
->inet_dport
, sk
);
117 /* OK, now commit destination to socket. */
118 sk_setup_caps(sk
, &rt
->dst
);
120 dp
->dccps_iss
= secure_dccp_sequence_number(inet
->inet_saddr
,
124 inet
->inet_id
= dp
->dccps_iss
^ jiffies
;
126 err
= dccp_connect(sk
);
134 * This unhashes the socket and releases the local port, if necessary.
136 dccp_set_state(sk
, DCCP_CLOSED
);
138 sk
->sk_route_caps
= 0;
139 inet
->inet_dport
= 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 dst
= inet_csk_update_pmtu(sk
, mtu
);
166 /* Something is about to be wrong... Remember soft error
167 * for the case, if this connection will not able to recover.
169 if (mtu
< dst_mtu(dst
) && ip_dont_fragment(sk
, dst
))
170 sk
->sk_err_soft
= EMSGSIZE
;
174 if (inet
->pmtudisc
!= IP_PMTUDISC_DONT
&&
175 ip_sk_accept_pmtu(sk
) &&
176 inet_csk(sk
)->icsk_pmtu_cookie
> mtu
) {
177 dccp_sync_mss(sk
, mtu
);
180 * From RFC 4340, sec. 14.1:
182 * DCCP-Sync packets are the best choice for upward
183 * probing, since DCCP-Sync probes do not risk application
186 dccp_send_sync(sk
, dp
->dccps_gsr
, DCCP_PKT_SYNC
);
187 } /* else let the usual retransmit timer handle it */
190 static void dccp_do_redirect(struct sk_buff
*skb
, struct sock
*sk
)
192 struct dst_entry
*dst
= __sk_dst_check(sk
, 0);
195 dst
->ops
->redirect(dst
, sk
, skb
);
198 void dccp_req_err(struct sock
*sk
, u64 seq
)
200 struct request_sock
*req
= inet_reqsk(sk
);
201 struct net
*net
= sock_net(sk
);
204 * ICMPs are not backlogged, hence we cannot get an established
209 if (!between48(seq
, dccp_rsk(req
)->dreq_iss
, dccp_rsk(req
)->dreq_gss
)) {
210 NET_INC_STATS_BH(net
, LINUX_MIB_OUTOFWINDOWICMPS
);
214 * Still in RESPOND, just remove it silently.
215 * There is no good way to pass the error to the newly
216 * created socket, and POSIX does not want network
217 * errors returned from accept().
219 inet_csk_reqsk_queue_drop(req
->rsk_listener
, req
);
222 EXPORT_SYMBOL(dccp_req_err
);
225 * This routine is called by the ICMP module when it gets some sort of error
226 * condition. If err < 0 then the socket should be closed and the error
227 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
228 * After adjustment header points to the first 8 bytes of the tcp header. We
229 * need to find the appropriate port.
231 * The locking strategy used here is very "optimistic". When someone else
232 * accesses the socket the ICMP is just dropped and for some paths there is no
233 * check at all. A more general error queue to queue errors for later handling
234 * is probably better.
236 static void dccp_v4_err(struct sk_buff
*skb
, u32 info
)
238 const struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
239 const u8 offset
= iph
->ihl
<< 2;
240 const struct dccp_hdr
*dh
= (struct dccp_hdr
*)(skb
->data
+ offset
);
241 struct dccp_sock
*dp
;
242 struct inet_sock
*inet
;
243 const int type
= icmp_hdr(skb
)->type
;
244 const int code
= icmp_hdr(skb
)->code
;
248 struct net
*net
= dev_net(skb
->dev
);
250 if (skb
->len
< offset
+ sizeof(*dh
) ||
251 skb
->len
< offset
+ __dccp_basic_hdr_len(dh
)) {
252 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
256 sk
= __inet_lookup_established(net
, &dccp_hashinfo
,
257 iph
->daddr
, dh
->dccph_dport
,
258 iph
->saddr
, ntohs(dh
->dccph_sport
),
261 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
265 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
266 inet_twsk_put(inet_twsk(sk
));
269 seq
= dccp_hdr_seq(dh
);
270 if (sk
->sk_state
== DCCP_NEW_SYN_RECV
)
271 return dccp_req_err(sk
, seq
);
274 /* If too many ICMPs get dropped on busy
275 * servers this needs to be solved differently.
277 if (sock_owned_by_user(sk
))
278 NET_INC_STATS_BH(net
, LINUX_MIB_LOCKDROPPEDICMPS
);
280 if (sk
->sk_state
== DCCP_CLOSED
)
284 if ((1 << sk
->sk_state
) & ~(DCCPF_REQUESTING
| DCCPF_LISTEN
) &&
285 !between48(seq
, dp
->dccps_awl
, dp
->dccps_awh
)) {
286 NET_INC_STATS_BH(net
, LINUX_MIB_OUTOFWINDOWICMPS
);
292 dccp_do_redirect(skb
, sk
);
294 case ICMP_SOURCE_QUENCH
:
295 /* Just silently ignore these. */
297 case ICMP_PARAMETERPROB
:
300 case ICMP_DEST_UNREACH
:
301 if (code
> NR_ICMP_UNREACH
)
304 if (code
== ICMP_FRAG_NEEDED
) { /* PMTU discovery (RFC1191) */
305 if (!sock_owned_by_user(sk
))
306 dccp_do_pmtu_discovery(sk
, iph
, info
);
310 err
= icmp_err_convert
[code
].errno
;
312 case ICMP_TIME_EXCEEDED
:
319 switch (sk
->sk_state
) {
320 case DCCP_REQUESTING
:
322 if (!sock_owned_by_user(sk
)) {
323 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
326 sk
->sk_error_report(sk
);
330 sk
->sk_err_soft
= err
;
334 /* If we've already connected we will keep trying
335 * until we time out, or the user gives up.
337 * rfc1122 4.2.3.9 allows to consider as hard errors
338 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
339 * but it is obsoleted by pmtu discovery).
341 * Note, that in modern internet, where routing is unreliable
342 * and in each dark corner broken firewalls sit, sending random
343 * errors ordered by their masters even this two messages finally lose
344 * their original sense (even Linux sends invalid PORT_UNREACHs)
346 * Now we are in compliance with RFCs.
351 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
353 sk
->sk_error_report(sk
);
354 } else /* Only an error on timeout */
355 sk
->sk_err_soft
= err
;
361 static inline __sum16
dccp_v4_csum_finish(struct sk_buff
*skb
,
362 __be32 src
, __be32 dst
)
364 return csum_tcpudp_magic(src
, dst
, skb
->len
, IPPROTO_DCCP
, skb
->csum
);
367 void dccp_v4_send_check(struct sock
*sk
, struct sk_buff
*skb
)
369 const struct inet_sock
*inet
= inet_sk(sk
);
370 struct dccp_hdr
*dh
= dccp_hdr(skb
);
372 dccp_csum_outgoing(skb
);
373 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
,
377 EXPORT_SYMBOL_GPL(dccp_v4_send_check
);
379 static inline u64
dccp_v4_init_sequence(const struct sk_buff
*skb
)
381 return secure_dccp_sequence_number(ip_hdr(skb
)->daddr
,
383 dccp_hdr(skb
)->dccph_dport
,
384 dccp_hdr(skb
)->dccph_sport
);
388 * The three way handshake has completed - we got a valid ACK or DATAACK -
389 * now create the new socket.
391 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
393 struct sock
*dccp_v4_request_recv_sock(struct sock
*sk
, struct sk_buff
*skb
,
394 struct request_sock
*req
,
395 struct dst_entry
*dst
)
397 struct inet_request_sock
*ireq
;
398 struct inet_sock
*newinet
;
401 if (sk_acceptq_is_full(sk
))
404 newsk
= dccp_create_openreq_child(sk
, req
, skb
);
408 newinet
= inet_sk(newsk
);
409 ireq
= inet_rsk(req
);
410 sk_daddr_set(newsk
, ireq
->ir_rmt_addr
);
411 sk_rcv_saddr_set(newsk
, ireq
->ir_loc_addr
);
412 newinet
->inet_saddr
= ireq
->ir_loc_addr
;
413 newinet
->inet_opt
= ireq
->opt
;
415 newinet
->mc_index
= inet_iif(skb
);
416 newinet
->mc_ttl
= ip_hdr(skb
)->ttl
;
417 newinet
->inet_id
= jiffies
;
419 if (dst
== NULL
&& (dst
= inet_csk_route_child_sock(sk
, newsk
, req
)) == NULL
)
422 sk_setup_caps(newsk
, dst
);
424 dccp_sync_mss(newsk
, dst_mtu(dst
));
426 if (__inet_inherit_port(sk
, newsk
) < 0)
428 __inet_hash_nolisten(newsk
, NULL
);
433 NET_INC_STATS_BH(sock_net(sk
), LINUX_MIB_LISTENOVERFLOWS
);
437 NET_INC_STATS_BH(sock_net(sk
), LINUX_MIB_LISTENDROPS
);
440 inet_csk_prepare_forced_close(newsk
);
444 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock
);
446 static struct sock
*dccp_v4_hnd_req(struct sock
*sk
, struct sk_buff
*skb
)
448 const struct dccp_hdr
*dh
= dccp_hdr(skb
);
449 const struct iphdr
*iph
= ip_hdr(skb
);
451 /* Find possible connection requests. */
452 struct request_sock
*req
= inet_csk_search_req(sk
, dh
->dccph_sport
,
453 iph
->saddr
, iph
->daddr
);
455 nsk
= dccp_check_req(sk
, skb
, req
);
459 nsk
= inet_lookup_established(sock_net(sk
), &dccp_hashinfo
,
460 iph
->saddr
, dh
->dccph_sport
,
461 iph
->daddr
, dh
->dccph_dport
,
464 if (nsk
->sk_state
!= DCCP_TIME_WAIT
) {
468 inet_twsk_put(inet_twsk(nsk
));
475 static struct dst_entry
* dccp_v4_route_skb(struct net
*net
, struct sock
*sk
,
479 const struct iphdr
*iph
= ip_hdr(skb
);
480 struct flowi4 fl4
= {
481 .flowi4_oif
= inet_iif(skb
),
484 .flowi4_tos
= RT_CONN_FLAGS(sk
),
485 .flowi4_proto
= sk
->sk_protocol
,
486 .fl4_sport
= dccp_hdr(skb
)->dccph_dport
,
487 .fl4_dport
= dccp_hdr(skb
)->dccph_sport
,
490 security_skb_classify_flow(skb
, flowi4_to_flowi(&fl4
));
491 rt
= ip_route_output_flow(net
, &fl4
, sk
);
493 IP_INC_STATS_BH(net
, IPSTATS_MIB_OUTNOROUTES
);
500 static int dccp_v4_send_response(struct sock
*sk
, struct request_sock
*req
)
504 struct dst_entry
*dst
;
507 dst
= inet_csk_route_req(sk
, &fl4
, req
);
511 skb
= dccp_make_response(sk
, dst
, req
);
513 const struct inet_request_sock
*ireq
= inet_rsk(req
);
514 struct dccp_hdr
*dh
= dccp_hdr(skb
);
516 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, ireq
->ir_loc_addr
,
518 err
= ip_build_and_send_pkt(skb
, sk
, ireq
->ir_loc_addr
,
521 err
= net_xmit_eval(err
);
529 static void dccp_v4_ctl_send_reset(struct sock
*sk
, struct sk_buff
*rxskb
)
532 const struct iphdr
*rxiph
;
534 struct dst_entry
*dst
;
535 struct net
*net
= dev_net(skb_dst(rxskb
)->dev
);
536 struct sock
*ctl_sk
= net
->dccp
.v4_ctl_sk
;
538 /* Never send a reset in response to a reset. */
539 if (dccp_hdr(rxskb
)->dccph_type
== DCCP_PKT_RESET
)
542 if (skb_rtable(rxskb
)->rt_type
!= RTN_LOCAL
)
545 dst
= dccp_v4_route_skb(net
, ctl_sk
, rxskb
);
549 skb
= dccp_ctl_make_reset(ctl_sk
, rxskb
);
553 rxiph
= ip_hdr(rxskb
);
554 dccp_hdr(skb
)->dccph_checksum
= dccp_v4_csum_finish(skb
, rxiph
->saddr
,
556 skb_dst_set(skb
, dst_clone(dst
));
558 bh_lock_sock(ctl_sk
);
559 err
= ip_build_and_send_pkt(skb
, ctl_sk
,
560 rxiph
->daddr
, rxiph
->saddr
, NULL
);
561 bh_unlock_sock(ctl_sk
);
563 if (net_xmit_eval(err
) == 0) {
564 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS
);
565 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS
);
571 static void dccp_v4_reqsk_destructor(struct request_sock
*req
)
573 dccp_feat_list_purge(&dccp_rsk(req
)->dreq_featneg
);
574 kfree(inet_rsk(req
)->opt
);
577 void dccp_syn_ack_timeout(const struct request_sock
*req
)
580 EXPORT_SYMBOL(dccp_syn_ack_timeout
);
582 static struct request_sock_ops dccp_request_sock_ops __read_mostly
= {
584 .obj_size
= sizeof(struct dccp_request_sock
),
585 .rtx_syn_ack
= dccp_v4_send_response
,
586 .send_ack
= dccp_reqsk_send_ack
,
587 .destructor
= dccp_v4_reqsk_destructor
,
588 .send_reset
= dccp_v4_ctl_send_reset
,
589 .syn_ack_timeout
= dccp_syn_ack_timeout
,
592 int dccp_v4_conn_request(struct sock
*sk
, struct sk_buff
*skb
)
594 struct inet_request_sock
*ireq
;
595 struct request_sock
*req
;
596 struct dccp_request_sock
*dreq
;
597 const __be32 service
= dccp_hdr_request(skb
)->dccph_req_service
;
598 struct dccp_skb_cb
*dcb
= DCCP_SKB_CB(skb
);
600 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
601 if (skb_rtable(skb
)->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
))
602 return 0; /* discard, don't send a reset here */
604 if (dccp_bad_service_code(sk
, service
)) {
605 dcb
->dccpd_reset_code
= DCCP_RESET_CODE_BAD_SERVICE_CODE
;
609 * TW buckets are converted to open requests without
610 * limitations, they conserve resources and peer is
611 * evidently real one.
613 dcb
->dccpd_reset_code
= DCCP_RESET_CODE_TOO_BUSY
;
614 if (inet_csk_reqsk_queue_is_full(sk
))
618 * Accept backlog is full. If we have already queued enough
619 * of warm entries in syn queue, drop request. It is better than
620 * clogging syn queue with openreqs with exponentially increasing
623 if (sk_acceptq_is_full(sk
) && inet_csk_reqsk_queue_young(sk
) > 1)
626 req
= inet_reqsk_alloc(&dccp_request_sock_ops
, sk
);
630 if (dccp_reqsk_init(req
, dccp_sk(sk
), skb
))
633 dreq
= dccp_rsk(req
);
634 if (dccp_parse_options(sk
, dreq
, skb
))
637 if (security_inet_conn_request(sk
, skb
, req
))
640 ireq
= inet_rsk(req
);
641 sk_rcv_saddr_set(req_to_sk(req
), ip_hdr(skb
)->daddr
);
642 sk_daddr_set(req_to_sk(req
), ip_hdr(skb
)->saddr
);
643 ireq
->ireq_family
= AF_INET
;
644 ireq
->ir_iif
= sk
->sk_bound_dev_if
;
647 * Step 3: Process LISTEN state
649 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
651 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
653 dreq
->dreq_isr
= dcb
->dccpd_seq
;
654 dreq
->dreq_gsr
= dreq
->dreq_isr
;
655 dreq
->dreq_iss
= dccp_v4_init_sequence(skb
);
656 dreq
->dreq_gss
= dreq
->dreq_iss
;
657 dreq
->dreq_service
= service
;
659 if (dccp_v4_send_response(sk
, req
))
662 inet_csk_reqsk_queue_hash_add(sk
, req
, DCCP_TIMEOUT_INIT
);
668 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
671 EXPORT_SYMBOL_GPL(dccp_v4_conn_request
);
673 int dccp_v4_do_rcv(struct sock
*sk
, struct sk_buff
*skb
)
675 struct dccp_hdr
*dh
= dccp_hdr(skb
);
677 if (sk
->sk_state
== DCCP_OPEN
) { /* Fast path */
678 if (dccp_rcv_established(sk
, skb
, dh
, skb
->len
))
684 * Step 3: Process LISTEN state
685 * If P.type == Request or P contains a valid Init Cookie option,
686 * (* Must scan the packet's options to check for Init
687 * Cookies. Only Init Cookies are processed here,
688 * however; other options are processed in Step 8. This
689 * scan need only be performed if the endpoint uses Init
691 * (* Generate a new socket and switch to that socket *)
692 * Set S := new socket for this port pair
694 * Choose S.ISS (initial seqno) or set from Init Cookies
695 * Initialize S.GAR := S.ISS
696 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
697 * Continue with S.state == RESPOND
698 * (* A Response packet will be generated in Step 11 *)
700 * Generate Reset(No Connection) unless P.type == Reset
701 * Drop packet and return
703 * NOTE: the check for the packet types is done in
704 * dccp_rcv_state_process
706 if (sk
->sk_state
== DCCP_LISTEN
) {
707 struct sock
*nsk
= dccp_v4_hnd_req(sk
, skb
);
713 if (dccp_child_process(sk
, nsk
, skb
))
719 if (dccp_rcv_state_process(sk
, skb
, dh
, skb
->len
))
724 dccp_v4_ctl_send_reset(sk
, skb
);
729 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv
);
732 * dccp_invalid_packet - check for malformed packets
733 * Implements RFC 4340, 8.5: Step 1: Check header basics
734 * Packets that fail these checks are ignored and do not receive Resets.
736 int dccp_invalid_packet(struct sk_buff
*skb
)
738 const struct dccp_hdr
*dh
;
741 if (skb
->pkt_type
!= PACKET_HOST
)
744 /* If the packet is shorter than 12 bytes, drop packet and return */
745 if (!pskb_may_pull(skb
, sizeof(struct dccp_hdr
))) {
746 DCCP_WARN("pskb_may_pull failed\n");
752 /* If P.type is not understood, drop packet and return */
753 if (dh
->dccph_type
>= DCCP_PKT_INVALID
) {
754 DCCP_WARN("invalid packet type\n");
759 * If P.Data Offset is too small for packet type, drop packet and return
761 if (dh
->dccph_doff
< dccp_hdr_len(skb
) / sizeof(u32
)) {
762 DCCP_WARN("P.Data Offset(%u) too small\n", dh
->dccph_doff
);
766 * If P.Data Offset is too too large for packet, drop packet and return
768 if (!pskb_may_pull(skb
, dh
->dccph_doff
* sizeof(u32
))) {
769 DCCP_WARN("P.Data Offset(%u) too large\n", dh
->dccph_doff
);
774 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
775 * has short sequence numbers), drop packet and return
777 if ((dh
->dccph_type
< DCCP_PKT_DATA
||
778 dh
->dccph_type
> DCCP_PKT_DATAACK
) && dh
->dccph_x
== 0) {
779 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
780 dccp_packet_name(dh
->dccph_type
));
785 * If P.CsCov is too large for the packet size, drop packet and return.
786 * This must come _before_ checksumming (not as RFC 4340 suggests).
788 cscov
= dccp_csum_coverage(skb
);
789 if (cscov
> skb
->len
) {
790 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
791 dh
->dccph_cscov
, skb
->len
);
795 /* If header checksum is incorrect, drop packet and return.
796 * (This step is completed in the AF-dependent functions.) */
797 skb
->csum
= skb_checksum(skb
, 0, cscov
, 0);
801 EXPORT_SYMBOL_GPL(dccp_invalid_packet
);
803 /* this is called when real data arrives */
804 static int dccp_v4_rcv(struct sk_buff
*skb
)
806 const struct dccp_hdr
*dh
;
807 const struct iphdr
*iph
;
811 /* Step 1: Check header basics */
813 if (dccp_invalid_packet(skb
))
817 /* Step 1: If header checksum is incorrect, drop packet and return */
818 if (dccp_v4_csum_finish(skb
, iph
->saddr
, iph
->daddr
)) {
819 DCCP_WARN("dropped packet with invalid checksum\n");
825 DCCP_SKB_CB(skb
)->dccpd_seq
= dccp_hdr_seq(dh
);
826 DCCP_SKB_CB(skb
)->dccpd_type
= dh
->dccph_type
;
828 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
829 dccp_packet_name(dh
->dccph_type
),
830 &iph
->saddr
, ntohs(dh
->dccph_sport
),
831 &iph
->daddr
, ntohs(dh
->dccph_dport
),
832 (unsigned long long) DCCP_SKB_CB(skb
)->dccpd_seq
);
834 if (dccp_packet_without_ack(skb
)) {
835 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= DCCP_PKT_WITHOUT_ACK_SEQ
;
836 dccp_pr_debug_cat("\n");
838 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= dccp_hdr_ack_seq(skb
);
839 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
840 DCCP_SKB_CB(skb
)->dccpd_ack_seq
);
844 * Look up flow ID in table and get corresponding socket */
845 sk
= __inet_lookup_skb(&dccp_hashinfo
, skb
,
846 dh
->dccph_sport
, dh
->dccph_dport
);
852 dccp_pr_debug("failed to look up flow ID in table and "
853 "get corresponding socket\n");
859 * ... or S.state == TIMEWAIT,
860 * Generate Reset(No Connection) unless P.type == Reset
861 * Drop packet and return
863 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
864 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
865 inet_twsk_put(inet_twsk(sk
));
870 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
871 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
872 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
874 min_cov
= dccp_sk(sk
)->dccps_pcrlen
;
875 if (dh
->dccph_cscov
&& (min_cov
== 0 || dh
->dccph_cscov
< min_cov
)) {
876 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
877 dh
->dccph_cscov
, min_cov
);
878 /* FIXME: "Such packets SHOULD be reported using Data Dropped
879 * options (Section 11.7) with Drop Code 0, Protocol
881 goto discard_and_relse
;
884 if (!xfrm4_policy_check(sk
, XFRM_POLICY_IN
, skb
))
885 goto discard_and_relse
;
888 return sk_receive_skb(sk
, skb
, 1);
891 if (!xfrm4_policy_check(NULL
, XFRM_POLICY_IN
, skb
))
896 * Generate Reset(No Connection) unless P.type == Reset
897 * Drop packet and return
899 if (dh
->dccph_type
!= DCCP_PKT_RESET
) {
900 DCCP_SKB_CB(skb
)->dccpd_reset_code
=
901 DCCP_RESET_CODE_NO_CONNECTION
;
902 dccp_v4_ctl_send_reset(sk
, skb
);
914 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops
= {
915 .queue_xmit
= ip_queue_xmit
,
916 .send_check
= dccp_v4_send_check
,
917 .rebuild_header
= inet_sk_rebuild_header
,
918 .conn_request
= dccp_v4_conn_request
,
919 .syn_recv_sock
= dccp_v4_request_recv_sock
,
920 .net_header_len
= sizeof(struct iphdr
),
921 .setsockopt
= ip_setsockopt
,
922 .getsockopt
= ip_getsockopt
,
923 .addr2sockaddr
= inet_csk_addr2sockaddr
,
924 .sockaddr_len
= sizeof(struct sockaddr_in
),
925 .bind_conflict
= inet_csk_bind_conflict
,
927 .compat_setsockopt
= compat_ip_setsockopt
,
928 .compat_getsockopt
= compat_ip_getsockopt
,
932 static int dccp_v4_init_sock(struct sock
*sk
)
934 static __u8 dccp_v4_ctl_sock_initialized
;
935 int err
= dccp_init_sock(sk
, dccp_v4_ctl_sock_initialized
);
938 if (unlikely(!dccp_v4_ctl_sock_initialized
))
939 dccp_v4_ctl_sock_initialized
= 1;
940 inet_csk(sk
)->icsk_af_ops
= &dccp_ipv4_af_ops
;
946 static struct timewait_sock_ops dccp_timewait_sock_ops
= {
947 .twsk_obj_size
= sizeof(struct inet_timewait_sock
),
950 static struct proto dccp_v4_prot
= {
952 .owner
= THIS_MODULE
,
954 .connect
= dccp_v4_connect
,
955 .disconnect
= dccp_disconnect
,
957 .init
= dccp_v4_init_sock
,
958 .setsockopt
= dccp_setsockopt
,
959 .getsockopt
= dccp_getsockopt
,
960 .sendmsg
= dccp_sendmsg
,
961 .recvmsg
= dccp_recvmsg
,
962 .backlog_rcv
= dccp_v4_do_rcv
,
964 .unhash
= inet_unhash
,
965 .accept
= inet_csk_accept
,
966 .get_port
= inet_csk_get_port
,
967 .shutdown
= dccp_shutdown
,
968 .destroy
= dccp_destroy_sock
,
969 .orphan_count
= &dccp_orphan_count
,
970 .max_header
= MAX_DCCP_HEADER
,
971 .obj_size
= sizeof(struct dccp_sock
),
972 .slab_flags
= SLAB_DESTROY_BY_RCU
,
973 .rsk_prot
= &dccp_request_sock_ops
,
974 .twsk_prot
= &dccp_timewait_sock_ops
,
975 .h
.hashinfo
= &dccp_hashinfo
,
977 .compat_setsockopt
= compat_dccp_setsockopt
,
978 .compat_getsockopt
= compat_dccp_getsockopt
,
982 static const struct net_protocol dccp_v4_protocol
= {
983 .handler
= dccp_v4_rcv
,
984 .err_handler
= dccp_v4_err
,
987 .icmp_strict_tag_validation
= 1,
990 static const struct proto_ops inet_dccp_ops
= {
992 .owner
= THIS_MODULE
,
993 .release
= inet_release
,
995 .connect
= inet_stream_connect
,
996 .socketpair
= sock_no_socketpair
,
997 .accept
= inet_accept
,
998 .getname
= inet_getname
,
999 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
1001 .ioctl
= inet_ioctl
,
1002 /* FIXME: work on inet_listen to rename it to sock_common_listen */
1003 .listen
= inet_dccp_listen
,
1004 .shutdown
= inet_shutdown
,
1005 .setsockopt
= sock_common_setsockopt
,
1006 .getsockopt
= sock_common_getsockopt
,
1007 .sendmsg
= inet_sendmsg
,
1008 .recvmsg
= sock_common_recvmsg
,
1009 .mmap
= sock_no_mmap
,
1010 .sendpage
= sock_no_sendpage
,
1011 #ifdef CONFIG_COMPAT
1012 .compat_setsockopt
= compat_sock_common_setsockopt
,
1013 .compat_getsockopt
= compat_sock_common_getsockopt
,
1017 static struct inet_protosw dccp_v4_protosw
= {
1019 .protocol
= IPPROTO_DCCP
,
1020 .prot
= &dccp_v4_prot
,
1021 .ops
= &inet_dccp_ops
,
1022 .flags
= INET_PROTOSW_ICSK
,
1025 static int __net_init
dccp_v4_init_net(struct net
*net
)
1027 if (dccp_hashinfo
.bhash
== NULL
)
1028 return -ESOCKTNOSUPPORT
;
1030 return inet_ctl_sock_create(&net
->dccp
.v4_ctl_sk
, PF_INET
,
1031 SOCK_DCCP
, IPPROTO_DCCP
, net
);
1034 static void __net_exit
dccp_v4_exit_net(struct net
*net
)
1036 inet_ctl_sock_destroy(net
->dccp
.v4_ctl_sk
);
1039 static struct pernet_operations dccp_v4_ops
= {
1040 .init
= dccp_v4_init_net
,
1041 .exit
= dccp_v4_exit_net
,
1044 static int __init
dccp_v4_init(void)
1046 int err
= proto_register(&dccp_v4_prot
, 1);
1051 err
= inet_add_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1053 goto out_proto_unregister
;
1055 inet_register_protosw(&dccp_v4_protosw
);
1057 err
= register_pernet_subsys(&dccp_v4_ops
);
1059 goto out_destroy_ctl_sock
;
1062 out_destroy_ctl_sock
:
1063 inet_unregister_protosw(&dccp_v4_protosw
);
1064 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1065 out_proto_unregister
:
1066 proto_unregister(&dccp_v4_prot
);
1070 static void __exit
dccp_v4_exit(void)
1072 unregister_pernet_subsys(&dccp_v4_ops
);
1073 inet_unregister_protosw(&dccp_v4_protosw
);
1074 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1075 proto_unregister(&dccp_v4_prot
);
1078 module_init(dccp_v4_init
);
1079 module_exit(dccp_v4_exit
);
1082 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1083 * values directly, Also cover the case where the protocol is not specified,
1084 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1086 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET
, 33, 6);
1087 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET
, 0, 6);
1088 MODULE_LICENSE("GPL");
1089 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1090 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");