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 lockdep_sock_is_held(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
207 if (!between48(seq
, dccp_rsk(req
)->dreq_iss
, dccp_rsk(req
)->dreq_gss
)) {
208 __NET_INC_STATS(net
, LINUX_MIB_OUTOFWINDOWICMPS
);
211 * Still in RESPOND, just remove it silently.
212 * There is no good way to pass the error to the newly
213 * created socket, and POSIX does not want network
214 * errors returned from accept().
216 inet_csk_reqsk_queue_drop(req
->rsk_listener
, req
);
220 EXPORT_SYMBOL(dccp_req_err
);
223 * This routine is called by the ICMP module when it gets some sort of error
224 * condition. If err < 0 then the socket should be closed and the error
225 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
226 * After adjustment header points to the first 8 bytes of the tcp header. We
227 * need to find the appropriate port.
229 * The locking strategy used here is very "optimistic". When someone else
230 * accesses the socket the ICMP is just dropped and for some paths there is no
231 * check at all. A more general error queue to queue errors for later handling
232 * is probably better.
234 static int dccp_v4_err(struct sk_buff
*skb
, u32 info
)
236 const struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
237 const u8 offset
= iph
->ihl
<< 2;
238 const struct dccp_hdr
*dh
;
239 struct dccp_sock
*dp
;
240 struct inet_sock
*inet
;
241 const int type
= icmp_hdr(skb
)->type
;
242 const int code
= icmp_hdr(skb
)->code
;
246 struct net
*net
= dev_net(skb
->dev
);
248 /* Only need dccph_dport & dccph_sport which are the first
249 * 4 bytes in dccp header.
250 * Our caller (icmp_socket_deliver()) already pulled 8 bytes for us.
252 BUILD_BUG_ON(offsetofend(struct dccp_hdr
, dccph_sport
) > 8);
253 BUILD_BUG_ON(offsetofend(struct dccp_hdr
, dccph_dport
) > 8);
254 dh
= (struct dccp_hdr
*)(skb
->data
+ offset
);
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(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 dccp_req_err(sk
, seq
);
276 /* If too many ICMPs get dropped on busy
277 * servers this needs to be solved differently.
279 if (sock_owned_by_user(sk
))
280 __NET_INC_STATS(net
, LINUX_MIB_LOCKDROPPEDICMPS
);
282 if (sk
->sk_state
== DCCP_CLOSED
)
286 if ((1 << sk
->sk_state
) & ~(DCCPF_REQUESTING
| DCCPF_LISTEN
) &&
287 !between48(seq
, dp
->dccps_awl
, dp
->dccps_awh
)) {
288 __NET_INC_STATS(net
, LINUX_MIB_OUTOFWINDOWICMPS
);
294 if (!sock_owned_by_user(sk
))
295 dccp_do_redirect(skb
, sk
);
297 case ICMP_SOURCE_QUENCH
:
298 /* Just silently ignore these. */
300 case ICMP_PARAMETERPROB
:
303 case ICMP_DEST_UNREACH
:
304 if (code
> NR_ICMP_UNREACH
)
307 if (code
== ICMP_FRAG_NEEDED
) { /* PMTU discovery (RFC1191) */
308 if (!sock_owned_by_user(sk
))
309 dccp_do_pmtu_discovery(sk
, iph
, info
);
313 err
= icmp_err_convert
[code
].errno
;
315 case ICMP_TIME_EXCEEDED
:
322 switch (sk
->sk_state
) {
323 case DCCP_REQUESTING
:
325 if (!sock_owned_by_user(sk
)) {
326 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS
);
329 sk
->sk_error_report(sk
);
333 sk
->sk_err_soft
= err
;
337 /* If we've already connected we will keep trying
338 * until we time out, or the user gives up.
340 * rfc1122 4.2.3.9 allows to consider as hard errors
341 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
342 * but it is obsoleted by pmtu discovery).
344 * Note, that in modern internet, where routing is unreliable
345 * and in each dark corner broken firewalls sit, sending random
346 * errors ordered by their masters even this two messages finally lose
347 * their original sense (even Linux sends invalid PORT_UNREACHs)
349 * Now we are in compliance with RFCs.
354 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
356 sk
->sk_error_report(sk
);
357 } else /* Only an error on timeout */
358 sk
->sk_err_soft
= err
;
365 static inline __sum16
dccp_v4_csum_finish(struct sk_buff
*skb
,
366 __be32 src
, __be32 dst
)
368 return csum_tcpudp_magic(src
, dst
, skb
->len
, IPPROTO_DCCP
, skb
->csum
);
371 void dccp_v4_send_check(struct sock
*sk
, struct sk_buff
*skb
)
373 const struct inet_sock
*inet
= inet_sk(sk
);
374 struct dccp_hdr
*dh
= dccp_hdr(skb
);
376 dccp_csum_outgoing(skb
);
377 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
,
381 EXPORT_SYMBOL_GPL(dccp_v4_send_check
);
383 static inline u64
dccp_v4_init_sequence(const struct sk_buff
*skb
)
385 return secure_dccp_sequence_number(ip_hdr(skb
)->daddr
,
387 dccp_hdr(skb
)->dccph_dport
,
388 dccp_hdr(skb
)->dccph_sport
);
392 * The three way handshake has completed - we got a valid ACK or DATAACK -
393 * now create the new socket.
395 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
397 struct sock
*dccp_v4_request_recv_sock(const struct sock
*sk
,
399 struct request_sock
*req
,
400 struct dst_entry
*dst
,
401 struct request_sock
*req_unhash
,
404 struct inet_request_sock
*ireq
;
405 struct inet_sock
*newinet
;
408 if (sk_acceptq_is_full(sk
))
411 newsk
= dccp_create_openreq_child(sk
, req
, skb
);
415 newinet
= inet_sk(newsk
);
416 ireq
= inet_rsk(req
);
417 sk_daddr_set(newsk
, ireq
->ir_rmt_addr
);
418 sk_rcv_saddr_set(newsk
, ireq
->ir_loc_addr
);
419 newinet
->inet_saddr
= ireq
->ir_loc_addr
;
420 RCU_INIT_POINTER(newinet
->inet_opt
, rcu_dereference(ireq
->ireq_opt
));
421 newinet
->mc_index
= inet_iif(skb
);
422 newinet
->mc_ttl
= ip_hdr(skb
)->ttl
;
423 newinet
->inet_id
= jiffies
;
425 if (dst
== NULL
&& (dst
= inet_csk_route_child_sock(sk
, newsk
, req
)) == NULL
)
428 sk_setup_caps(newsk
, dst
);
430 dccp_sync_mss(newsk
, dst_mtu(dst
));
432 if (__inet_inherit_port(sk
, newsk
) < 0)
434 *own_req
= inet_ehash_nolisten(newsk
, req_to_sk(req_unhash
));
436 ireq
->ireq_opt
= NULL
;
438 newinet
->inet_opt
= NULL
;
442 __NET_INC_STATS(sock_net(sk
), LINUX_MIB_LISTENOVERFLOWS
);
446 __NET_INC_STATS(sock_net(sk
), LINUX_MIB_LISTENDROPS
);
449 newinet
->inet_opt
= NULL
;
450 inet_csk_prepare_forced_close(newsk
);
454 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock
);
456 static struct dst_entry
* dccp_v4_route_skb(struct net
*net
, struct sock
*sk
,
460 const struct iphdr
*iph
= ip_hdr(skb
);
461 struct flowi4 fl4
= {
462 .flowi4_oif
= inet_iif(skb
),
465 .flowi4_tos
= RT_CONN_FLAGS(sk
),
466 .flowi4_proto
= sk
->sk_protocol
,
467 .fl4_sport
= dccp_hdr(skb
)->dccph_dport
,
468 .fl4_dport
= dccp_hdr(skb
)->dccph_sport
,
471 security_skb_classify_flow(skb
, flowi4_to_flowi(&fl4
));
472 rt
= ip_route_output_flow(net
, &fl4
, sk
);
474 IP_INC_STATS(net
, IPSTATS_MIB_OUTNOROUTES
);
481 static int dccp_v4_send_response(const struct sock
*sk
, struct request_sock
*req
)
485 struct dst_entry
*dst
;
488 dst
= inet_csk_route_req(sk
, &fl4
, req
);
492 skb
= dccp_make_response(sk
, dst
, req
);
494 const struct inet_request_sock
*ireq
= inet_rsk(req
);
495 struct dccp_hdr
*dh
= dccp_hdr(skb
);
497 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, ireq
->ir_loc_addr
,
500 err
= ip_build_and_send_pkt(skb
, sk
, ireq
->ir_loc_addr
,
502 rcu_dereference(ireq
->ireq_opt
));
504 err
= net_xmit_eval(err
);
512 static void dccp_v4_ctl_send_reset(const struct sock
*sk
, struct sk_buff
*rxskb
)
515 const struct iphdr
*rxiph
;
517 struct dst_entry
*dst
;
518 struct net
*net
= dev_net(skb_dst(rxskb
)->dev
);
519 struct sock
*ctl_sk
= net
->dccp
.v4_ctl_sk
;
521 /* Never send a reset in response to a reset. */
522 if (dccp_hdr(rxskb
)->dccph_type
== DCCP_PKT_RESET
)
525 if (skb_rtable(rxskb
)->rt_type
!= RTN_LOCAL
)
528 dst
= dccp_v4_route_skb(net
, ctl_sk
, rxskb
);
532 skb
= dccp_ctl_make_reset(ctl_sk
, rxskb
);
536 rxiph
= ip_hdr(rxskb
);
537 dccp_hdr(skb
)->dccph_checksum
= dccp_v4_csum_finish(skb
, rxiph
->saddr
,
539 skb_dst_set(skb
, dst_clone(dst
));
542 bh_lock_sock(ctl_sk
);
543 err
= ip_build_and_send_pkt(skb
, ctl_sk
,
544 rxiph
->daddr
, rxiph
->saddr
, NULL
);
545 bh_unlock_sock(ctl_sk
);
547 if (net_xmit_eval(err
) == 0) {
548 __DCCP_INC_STATS(DCCP_MIB_OUTSEGS
);
549 __DCCP_INC_STATS(DCCP_MIB_OUTRSTS
);
556 static void dccp_v4_reqsk_destructor(struct request_sock
*req
)
558 dccp_feat_list_purge(&dccp_rsk(req
)->dreq_featneg
);
559 kfree(rcu_dereference_protected(inet_rsk(req
)->ireq_opt
, 1));
562 void dccp_syn_ack_timeout(const struct request_sock
*req
)
565 EXPORT_SYMBOL(dccp_syn_ack_timeout
);
567 static struct request_sock_ops dccp_request_sock_ops __read_mostly
= {
569 .obj_size
= sizeof(struct dccp_request_sock
),
570 .rtx_syn_ack
= dccp_v4_send_response
,
571 .send_ack
= dccp_reqsk_send_ack
,
572 .destructor
= dccp_v4_reqsk_destructor
,
573 .send_reset
= dccp_v4_ctl_send_reset
,
574 .syn_ack_timeout
= dccp_syn_ack_timeout
,
577 int dccp_v4_conn_request(struct sock
*sk
, struct sk_buff
*skb
)
579 struct inet_request_sock
*ireq
;
580 struct request_sock
*req
;
581 struct dccp_request_sock
*dreq
;
582 const __be32 service
= dccp_hdr_request(skb
)->dccph_req_service
;
583 struct dccp_skb_cb
*dcb
= DCCP_SKB_CB(skb
);
585 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
586 if (skb_rtable(skb
)->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
))
587 return 0; /* discard, don't send a reset here */
589 if (dccp_bad_service_code(sk
, service
)) {
590 dcb
->dccpd_reset_code
= DCCP_RESET_CODE_BAD_SERVICE_CODE
;
594 * TW buckets are converted to open requests without
595 * limitations, they conserve resources and peer is
596 * evidently real one.
598 dcb
->dccpd_reset_code
= DCCP_RESET_CODE_TOO_BUSY
;
599 if (inet_csk_reqsk_queue_is_full(sk
))
602 if (sk_acceptq_is_full(sk
))
605 req
= inet_reqsk_alloc(&dccp_request_sock_ops
, sk
, true);
609 if (dccp_reqsk_init(req
, dccp_sk(sk
), skb
))
612 dreq
= dccp_rsk(req
);
613 if (dccp_parse_options(sk
, dreq
, skb
))
616 if (security_inet_conn_request(sk
, skb
, req
))
619 ireq
= inet_rsk(req
);
620 sk_rcv_saddr_set(req_to_sk(req
), ip_hdr(skb
)->daddr
);
621 sk_daddr_set(req_to_sk(req
), ip_hdr(skb
)->saddr
);
622 ireq
->ir_mark
= inet_request_mark(sk
, skb
);
623 ireq
->ireq_family
= AF_INET
;
624 ireq
->ir_iif
= sk
->sk_bound_dev_if
;
627 * Step 3: Process LISTEN state
629 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
631 * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
633 dreq
->dreq_isr
= dcb
->dccpd_seq
;
634 dreq
->dreq_gsr
= dreq
->dreq_isr
;
635 dreq
->dreq_iss
= dccp_v4_init_sequence(skb
);
636 dreq
->dreq_gss
= dreq
->dreq_iss
;
637 dreq
->dreq_service
= service
;
639 if (dccp_v4_send_response(sk
, req
))
642 inet_csk_reqsk_queue_hash_add(sk
, req
, DCCP_TIMEOUT_INIT
);
649 __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS
);
652 EXPORT_SYMBOL_GPL(dccp_v4_conn_request
);
654 int dccp_v4_do_rcv(struct sock
*sk
, struct sk_buff
*skb
)
656 struct dccp_hdr
*dh
= dccp_hdr(skb
);
658 if (sk
->sk_state
== DCCP_OPEN
) { /* Fast path */
659 if (dccp_rcv_established(sk
, skb
, dh
, skb
->len
))
665 * Step 3: Process LISTEN state
666 * If P.type == Request or P contains a valid Init Cookie option,
667 * (* Must scan the packet's options to check for Init
668 * Cookies. Only Init Cookies are processed here,
669 * however; other options are processed in Step 8. This
670 * scan need only be performed if the endpoint uses Init
672 * (* Generate a new socket and switch to that socket *)
673 * Set S := new socket for this port pair
675 * Choose S.ISS (initial seqno) or set from Init Cookies
676 * Initialize S.GAR := S.ISS
677 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
678 * Continue with S.state == RESPOND
679 * (* A Response packet will be generated in Step 11 *)
681 * Generate Reset(No Connection) unless P.type == Reset
682 * Drop packet and return
684 * NOTE: the check for the packet types is done in
685 * dccp_rcv_state_process
688 if (dccp_rcv_state_process(sk
, skb
, dh
, skb
->len
))
693 dccp_v4_ctl_send_reset(sk
, skb
);
697 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv
);
700 * dccp_invalid_packet - check for malformed packets
701 * Implements RFC 4340, 8.5: Step 1: Check header basics
702 * Packets that fail these checks are ignored and do not receive Resets.
704 int dccp_invalid_packet(struct sk_buff
*skb
)
706 const struct dccp_hdr
*dh
;
710 if (skb
->pkt_type
!= PACKET_HOST
)
713 /* If the packet is shorter than 12 bytes, drop packet and return */
714 if (!pskb_may_pull(skb
, sizeof(struct dccp_hdr
))) {
715 DCCP_WARN("pskb_may_pull failed\n");
721 /* If P.type is not understood, drop packet and return */
722 if (dh
->dccph_type
>= DCCP_PKT_INVALID
) {
723 DCCP_WARN("invalid packet type\n");
728 * If P.Data Offset is too small for packet type, drop packet and return
730 dccph_doff
= dh
->dccph_doff
;
731 if (dccph_doff
< dccp_hdr_len(skb
) / sizeof(u32
)) {
732 DCCP_WARN("P.Data Offset(%u) too small\n", dccph_doff
);
736 * If P.Data Offset is too too large for packet, drop packet and return
738 if (!pskb_may_pull(skb
, dccph_doff
* sizeof(u32
))) {
739 DCCP_WARN("P.Data Offset(%u) too large\n", dccph_doff
);
744 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
745 * has short sequence numbers), drop packet and return
747 if ((dh
->dccph_type
< DCCP_PKT_DATA
||
748 dh
->dccph_type
> DCCP_PKT_DATAACK
) && dh
->dccph_x
== 0) {
749 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
750 dccp_packet_name(dh
->dccph_type
));
755 * If P.CsCov is too large for the packet size, drop packet and return.
756 * This must come _before_ checksumming (not as RFC 4340 suggests).
758 cscov
= dccp_csum_coverage(skb
);
759 if (cscov
> skb
->len
) {
760 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
761 dh
->dccph_cscov
, skb
->len
);
765 /* If header checksum is incorrect, drop packet and return.
766 * (This step is completed in the AF-dependent functions.) */
767 skb
->csum
= skb_checksum(skb
, 0, cscov
, 0);
771 EXPORT_SYMBOL_GPL(dccp_invalid_packet
);
773 /* this is called when real data arrives */
774 static int dccp_v4_rcv(struct sk_buff
*skb
)
776 const struct dccp_hdr
*dh
;
777 const struct iphdr
*iph
;
782 /* Step 1: Check header basics */
784 if (dccp_invalid_packet(skb
))
788 /* Step 1: If header checksum is incorrect, drop packet and return */
789 if (dccp_v4_csum_finish(skb
, iph
->saddr
, iph
->daddr
)) {
790 DCCP_WARN("dropped packet with invalid checksum\n");
796 DCCP_SKB_CB(skb
)->dccpd_seq
= dccp_hdr_seq(dh
);
797 DCCP_SKB_CB(skb
)->dccpd_type
= dh
->dccph_type
;
799 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
800 dccp_packet_name(dh
->dccph_type
),
801 &iph
->saddr
, ntohs(dh
->dccph_sport
),
802 &iph
->daddr
, ntohs(dh
->dccph_dport
),
803 (unsigned long long) DCCP_SKB_CB(skb
)->dccpd_seq
);
805 if (dccp_packet_without_ack(skb
)) {
806 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= DCCP_PKT_WITHOUT_ACK_SEQ
;
807 dccp_pr_debug_cat("\n");
809 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= dccp_hdr_ack_seq(skb
);
810 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
811 DCCP_SKB_CB(skb
)->dccpd_ack_seq
);
815 sk
= __inet_lookup_skb(&dccp_hashinfo
, skb
, __dccp_hdr_len(dh
),
816 dh
->dccph_sport
, dh
->dccph_dport
, 0, &refcounted
);
818 dccp_pr_debug("failed to look up flow ID in table and "
819 "get corresponding socket\n");
825 * ... or S.state == TIMEWAIT,
826 * Generate Reset(No Connection) unless P.type == Reset
827 * Drop packet and return
829 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
830 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
831 inet_twsk_put(inet_twsk(sk
));
835 if (sk
->sk_state
== DCCP_NEW_SYN_RECV
) {
836 struct request_sock
*req
= inet_reqsk(sk
);
839 sk
= req
->rsk_listener
;
840 if (unlikely(sk
->sk_state
!= DCCP_LISTEN
)) {
841 inet_csk_reqsk_queue_drop_and_put(sk
, req
);
846 nsk
= dccp_check_req(sk
, skb
, req
);
849 goto discard_and_relse
;
853 } else if (dccp_child_process(sk
, nsk
, skb
)) {
854 dccp_v4_ctl_send_reset(sk
, skb
);
855 goto discard_and_relse
;
862 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
863 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
864 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
866 min_cov
= dccp_sk(sk
)->dccps_pcrlen
;
867 if (dh
->dccph_cscov
&& (min_cov
== 0 || dh
->dccph_cscov
< min_cov
)) {
868 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
869 dh
->dccph_cscov
, min_cov
);
870 /* FIXME: "Such packets SHOULD be reported using Data Dropped
871 * options (Section 11.7) with Drop Code 0, Protocol
873 goto discard_and_relse
;
876 if (!xfrm4_policy_check(sk
, XFRM_POLICY_IN
, skb
))
877 goto discard_and_relse
;
880 return __sk_receive_skb(sk
, skb
, 1, dh
->dccph_doff
* 4, refcounted
);
883 if (!xfrm4_policy_check(NULL
, XFRM_POLICY_IN
, skb
))
888 * Generate Reset(No Connection) unless P.type == Reset
889 * Drop packet and return
891 if (dh
->dccph_type
!= DCCP_PKT_RESET
) {
892 DCCP_SKB_CB(skb
)->dccpd_reset_code
=
893 DCCP_RESET_CODE_NO_CONNECTION
;
894 dccp_v4_ctl_send_reset(sk
, skb
);
907 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops
= {
908 .queue_xmit
= ip_queue_xmit
,
909 .send_check
= dccp_v4_send_check
,
910 .rebuild_header
= inet_sk_rebuild_header
,
911 .conn_request
= dccp_v4_conn_request
,
912 .syn_recv_sock
= dccp_v4_request_recv_sock
,
913 .net_header_len
= sizeof(struct iphdr
),
914 .setsockopt
= ip_setsockopt
,
915 .getsockopt
= ip_getsockopt
,
916 .addr2sockaddr
= inet_csk_addr2sockaddr
,
917 .sockaddr_len
= sizeof(struct sockaddr_in
),
919 .compat_setsockopt
= compat_ip_setsockopt
,
920 .compat_getsockopt
= compat_ip_getsockopt
,
924 static int dccp_v4_init_sock(struct sock
*sk
)
926 static __u8 dccp_v4_ctl_sock_initialized
;
927 int err
= dccp_init_sock(sk
, dccp_v4_ctl_sock_initialized
);
930 if (unlikely(!dccp_v4_ctl_sock_initialized
))
931 dccp_v4_ctl_sock_initialized
= 1;
932 inet_csk(sk
)->icsk_af_ops
= &dccp_ipv4_af_ops
;
938 static struct timewait_sock_ops dccp_timewait_sock_ops
= {
939 .twsk_obj_size
= sizeof(struct inet_timewait_sock
),
942 static struct proto dccp_v4_prot
= {
944 .owner
= THIS_MODULE
,
946 .connect
= dccp_v4_connect
,
947 .disconnect
= dccp_disconnect
,
949 .init
= dccp_v4_init_sock
,
950 .setsockopt
= dccp_setsockopt
,
951 .getsockopt
= dccp_getsockopt
,
952 .sendmsg
= dccp_sendmsg
,
953 .recvmsg
= dccp_recvmsg
,
954 .backlog_rcv
= dccp_v4_do_rcv
,
956 .unhash
= inet_unhash
,
957 .accept
= inet_csk_accept
,
958 .get_port
= inet_csk_get_port
,
959 .shutdown
= dccp_shutdown
,
960 .destroy
= dccp_destroy_sock
,
961 .orphan_count
= &dccp_orphan_count
,
962 .max_header
= MAX_DCCP_HEADER
,
963 .obj_size
= sizeof(struct dccp_sock
),
964 .slab_flags
= SLAB_TYPESAFE_BY_RCU
,
965 .rsk_prot
= &dccp_request_sock_ops
,
966 .twsk_prot
= &dccp_timewait_sock_ops
,
967 .h
.hashinfo
= &dccp_hashinfo
,
969 .compat_setsockopt
= compat_dccp_setsockopt
,
970 .compat_getsockopt
= compat_dccp_getsockopt
,
974 static const struct net_protocol dccp_v4_protocol
= {
975 .handler
= dccp_v4_rcv
,
976 .err_handler
= dccp_v4_err
,
979 .icmp_strict_tag_validation
= 1,
982 static const struct proto_ops inet_dccp_ops
= {
984 .owner
= THIS_MODULE
,
985 .release
= inet_release
,
987 .connect
= inet_stream_connect
,
988 .socketpair
= sock_no_socketpair
,
989 .accept
= inet_accept
,
990 .getname
= inet_getname
,
991 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
994 /* FIXME: work on inet_listen to rename it to sock_common_listen */
995 .listen
= inet_dccp_listen
,
996 .shutdown
= inet_shutdown
,
997 .setsockopt
= sock_common_setsockopt
,
998 .getsockopt
= sock_common_getsockopt
,
999 .sendmsg
= inet_sendmsg
,
1000 .recvmsg
= sock_common_recvmsg
,
1001 .mmap
= sock_no_mmap
,
1002 .sendpage
= sock_no_sendpage
,
1003 #ifdef CONFIG_COMPAT
1004 .compat_setsockopt
= compat_sock_common_setsockopt
,
1005 .compat_getsockopt
= compat_sock_common_getsockopt
,
1009 static struct inet_protosw dccp_v4_protosw
= {
1011 .protocol
= IPPROTO_DCCP
,
1012 .prot
= &dccp_v4_prot
,
1013 .ops
= &inet_dccp_ops
,
1014 .flags
= INET_PROTOSW_ICSK
,
1017 static int __net_init
dccp_v4_init_net(struct net
*net
)
1019 if (dccp_hashinfo
.bhash
== NULL
)
1020 return -ESOCKTNOSUPPORT
;
1022 return inet_ctl_sock_create(&net
->dccp
.v4_ctl_sk
, PF_INET
,
1023 SOCK_DCCP
, IPPROTO_DCCP
, net
);
1026 static void __net_exit
dccp_v4_exit_net(struct net
*net
)
1028 inet_ctl_sock_destroy(net
->dccp
.v4_ctl_sk
);
1031 static void __net_exit
dccp_v4_exit_batch(struct list_head
*net_exit_list
)
1033 inet_twsk_purge(&dccp_hashinfo
, AF_INET
);
1036 static struct pernet_operations dccp_v4_ops
= {
1037 .init
= dccp_v4_init_net
,
1038 .exit
= dccp_v4_exit_net
,
1039 .exit_batch
= dccp_v4_exit_batch
,
1042 static int __init
dccp_v4_init(void)
1044 int err
= proto_register(&dccp_v4_prot
, 1);
1049 inet_register_protosw(&dccp_v4_protosw
);
1051 err
= register_pernet_subsys(&dccp_v4_ops
);
1053 goto out_destroy_ctl_sock
;
1055 err
= inet_add_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1057 goto out_proto_unregister
;
1061 out_proto_unregister
:
1062 unregister_pernet_subsys(&dccp_v4_ops
);
1063 out_destroy_ctl_sock
:
1064 inet_unregister_protosw(&dccp_v4_protosw
);
1065 proto_unregister(&dccp_v4_prot
);
1069 static void __exit
dccp_v4_exit(void)
1071 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1072 unregister_pernet_subsys(&dccp_v4_ops
);
1073 inet_unregister_protosw(&dccp_v4_protosw
);
1074 proto_unregister(&dccp_v4_prot
);
1077 module_init(dccp_v4_init
);
1078 module_exit(dccp_v4_exit
);
1081 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1082 * values directly, Also cover the case where the protocol is not specified,
1083 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1085 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET
, 33, 6);
1086 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET
, 0, 6);
1087 MODULE_LICENSE("GPL");
1088 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1089 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");