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
, 1);
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
);
116 dp
->dccps_iss
= secure_dccp_sequence_number(inet
->saddr
, inet
->daddr
,
117 inet
->sport
, inet
->dport
);
118 inet
->id
= dp
->dccps_iss
^ jiffies
;
120 err
= dccp_connect(sk
);
128 * This unhashes the socket and releases the local port, if necessary.
130 dccp_set_state(sk
, DCCP_CLOSED
);
132 sk
->sk_route_caps
= 0;
137 EXPORT_SYMBOL_GPL(dccp_v4_connect
);
140 * This routine does path mtu discovery as defined in RFC1191.
142 static inline void dccp_do_pmtu_discovery(struct sock
*sk
,
143 const struct iphdr
*iph
,
146 struct dst_entry
*dst
;
147 const struct inet_sock
*inet
= inet_sk(sk
);
148 const struct dccp_sock
*dp
= dccp_sk(sk
);
150 /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
151 * send out by Linux are always < 576bytes so they should go through
154 if (sk
->sk_state
== DCCP_LISTEN
)
157 /* We don't check in the destentry if pmtu discovery is forbidden
158 * on this route. We just assume that no packet_to_big packets
159 * are send back when pmtu discovery is not active.
160 * There is a small race when the user changes this flag in the
161 * route, but I think that's acceptable.
163 if ((dst
= __sk_dst_check(sk
, 0)) == NULL
)
166 dst
->ops
->update_pmtu(dst
, mtu
);
168 /* Something is about to be wrong... Remember soft error
169 * for the case, if this connection will not able to recover.
171 if (mtu
< dst_mtu(dst
) && ip_dont_fragment(sk
, dst
))
172 sk
->sk_err_soft
= EMSGSIZE
;
176 if (inet
->pmtudisc
!= IP_PMTUDISC_DONT
&&
177 inet_csk(sk
)->icsk_pmtu_cookie
> mtu
) {
178 dccp_sync_mss(sk
, mtu
);
181 * From RFC 4340, sec. 14.1:
183 * DCCP-Sync packets are the best choice for upward
184 * probing, since DCCP-Sync probes do not risk application
187 dccp_send_sync(sk
, dp
->dccps_gsr
, DCCP_PKT_SYNC
);
188 } /* else let the usual retransmit timer handle it */
192 * This routine is called by the ICMP module when it gets some sort of error
193 * condition. If err < 0 then the socket should be closed and the error
194 * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
195 * After adjustment header points to the first 8 bytes of the tcp header. We
196 * need to find the appropriate port.
198 * The locking strategy used here is very "optimistic". When someone else
199 * accesses the socket the ICMP is just dropped and for some paths there is no
200 * check at all. A more general error queue to queue errors for later handling
201 * is probably better.
203 static void dccp_v4_err(struct sk_buff
*skb
, u32 info
)
205 const struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
206 const struct dccp_hdr
*dh
= (struct dccp_hdr
*)(skb
->data
+
208 struct dccp_sock
*dp
;
209 struct inet_sock
*inet
;
210 const int type
= icmp_hdr(skb
)->type
;
211 const int code
= icmp_hdr(skb
)->code
;
216 if (skb
->len
< (iph
->ihl
<< 2) + 8) {
217 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
221 sk
= inet_lookup(&dccp_hashinfo
, iph
->daddr
, dh
->dccph_dport
,
222 iph
->saddr
, dh
->dccph_sport
, inet_iif(skb
));
224 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
228 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
229 inet_twsk_put(inet_twsk(sk
));
234 /* If too many ICMPs get dropped on busy
235 * servers this needs to be solved differently.
237 if (sock_owned_by_user(sk
))
238 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS
);
240 if (sk
->sk_state
== DCCP_CLOSED
)
244 seq
= dccp_hdr_seq(skb
);
245 if (sk
->sk_state
!= DCCP_LISTEN
&&
246 !between48(seq
, dp
->dccps_swl
, dp
->dccps_swh
)) {
247 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS
);
252 case ICMP_SOURCE_QUENCH
:
253 /* Just silently ignore these. */
255 case ICMP_PARAMETERPROB
:
258 case ICMP_DEST_UNREACH
:
259 if (code
> NR_ICMP_UNREACH
)
262 if (code
== ICMP_FRAG_NEEDED
) { /* PMTU discovery (RFC1191) */
263 if (!sock_owned_by_user(sk
))
264 dccp_do_pmtu_discovery(sk
, iph
, info
);
268 err
= icmp_err_convert
[code
].errno
;
270 case ICMP_TIME_EXCEEDED
:
277 switch (sk
->sk_state
) {
278 struct request_sock
*req
, **prev
;
280 if (sock_owned_by_user(sk
))
282 req
= inet_csk_search_req(sk
, &prev
, dh
->dccph_dport
,
283 iph
->daddr
, iph
->saddr
);
288 * ICMPs are not backlogged, hence we cannot get an established
293 if (seq
!= dccp_rsk(req
)->dreq_iss
) {
294 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS
);
298 * Still in RESPOND, just remove it silently.
299 * There is no good way to pass the error to the newly
300 * created socket, and POSIX does not want network
301 * errors returned from accept().
303 inet_csk_reqsk_queue_drop(sk
, req
, prev
);
306 case DCCP_REQUESTING
:
308 if (!sock_owned_by_user(sk
)) {
309 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
312 sk
->sk_error_report(sk
);
316 sk
->sk_err_soft
= err
;
320 /* If we've already connected we will keep trying
321 * until we time out, or the user gives up.
323 * rfc1122 4.2.3.9 allows to consider as hard errors
324 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
325 * but it is obsoleted by pmtu discovery).
327 * Note, that in modern internet, where routing is unreliable
328 * and in each dark corner broken firewalls sit, sending random
329 * errors ordered by their masters even this two messages finally lose
330 * their original sense (even Linux sends invalid PORT_UNREACHs)
332 * Now we are in compliance with RFCs.
337 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
339 sk
->sk_error_report(sk
);
340 } else /* Only an error on timeout */
341 sk
->sk_err_soft
= err
;
347 static inline __sum16
dccp_v4_csum_finish(struct sk_buff
*skb
,
348 __be32 src
, __be32 dst
)
350 return csum_tcpudp_magic(src
, dst
, skb
->len
, IPPROTO_DCCP
, skb
->csum
);
353 void dccp_v4_send_check(struct sock
*sk
, int unused
, struct sk_buff
*skb
)
355 const struct inet_sock
*inet
= inet_sk(sk
);
356 struct dccp_hdr
*dh
= dccp_hdr(skb
);
358 dccp_csum_outgoing(skb
);
359 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, inet
->saddr
, inet
->daddr
);
362 EXPORT_SYMBOL_GPL(dccp_v4_send_check
);
364 static inline u64
dccp_v4_init_sequence(const struct sk_buff
*skb
)
366 return secure_dccp_sequence_number(ip_hdr(skb
)->daddr
,
368 dccp_hdr(skb
)->dccph_dport
,
369 dccp_hdr(skb
)->dccph_sport
);
373 * The three way handshake has completed - we got a valid ACK or DATAACK -
374 * now create the new socket.
376 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
378 struct sock
*dccp_v4_request_recv_sock(struct sock
*sk
, struct sk_buff
*skb
,
379 struct request_sock
*req
,
380 struct dst_entry
*dst
)
382 struct inet_request_sock
*ireq
;
383 struct inet_sock
*newinet
;
386 if (sk_acceptq_is_full(sk
))
389 if (dst
== NULL
&& (dst
= inet_csk_route_req(sk
, req
)) == NULL
)
392 newsk
= dccp_create_openreq_child(sk
, req
, skb
);
396 sk_setup_caps(newsk
, dst
);
398 newinet
= inet_sk(newsk
);
399 ireq
= inet_rsk(req
);
400 newinet
->daddr
= ireq
->rmt_addr
;
401 newinet
->rcv_saddr
= ireq
->loc_addr
;
402 newinet
->saddr
= ireq
->loc_addr
;
403 newinet
->opt
= ireq
->opt
;
405 newinet
->mc_index
= inet_iif(skb
);
406 newinet
->mc_ttl
= ip_hdr(skb
)->ttl
;
407 newinet
->id
= jiffies
;
409 dccp_sync_mss(newsk
, dst_mtu(dst
));
411 __inet_hash(&dccp_hashinfo
, newsk
, 0);
412 __inet_inherit_port(&dccp_hashinfo
, sk
, newsk
);
417 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS
);
419 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS
);
424 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock
);
426 static struct sock
*dccp_v4_hnd_req(struct sock
*sk
, struct sk_buff
*skb
)
428 const struct dccp_hdr
*dh
= dccp_hdr(skb
);
429 const struct iphdr
*iph
= ip_hdr(skb
);
431 struct request_sock
**prev
;
432 /* Find possible connection requests. */
433 struct request_sock
*req
= inet_csk_search_req(sk
, &prev
,
435 iph
->saddr
, iph
->daddr
);
437 return dccp_check_req(sk
, skb
, req
, prev
);
439 nsk
= inet_lookup_established(&dccp_hashinfo
,
440 iph
->saddr
, dh
->dccph_sport
,
441 iph
->daddr
, dh
->dccph_dport
,
444 if (nsk
->sk_state
!= DCCP_TIME_WAIT
) {
448 inet_twsk_put(inet_twsk(nsk
));
455 static struct dst_entry
* dccp_v4_route_skb(struct sock
*sk
,
459 struct flowi fl
= { .oif
= ((struct rtable
*)skb
->dst
)->rt_iif
,
461 { .daddr
= ip_hdr(skb
)->saddr
,
462 .saddr
= ip_hdr(skb
)->daddr
,
463 .tos
= RT_CONN_FLAGS(sk
) } },
464 .proto
= sk
->sk_protocol
,
466 { .sport
= dccp_hdr(skb
)->dccph_dport
,
467 .dport
= dccp_hdr(skb
)->dccph_sport
}
471 security_skb_classify_flow(skb
, &fl
);
472 if (ip_route_output_flow(&rt
, &fl
, sk
, 0)) {
473 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES
);
480 static int dccp_v4_send_response(struct sock
*sk
, struct request_sock
*req
,
481 struct dst_entry
*dst
)
486 /* First, grab a route. */
488 if (dst
== NULL
&& (dst
= inet_csk_route_req(sk
, req
)) == NULL
)
491 skb
= dccp_make_response(sk
, dst
, req
);
493 const struct inet_request_sock
*ireq
= inet_rsk(req
);
494 struct dccp_hdr
*dh
= dccp_hdr(skb
);
496 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, ireq
->loc_addr
,
498 memset(&(IPCB(skb
)->opt
), 0, sizeof(IPCB(skb
)->opt
));
499 err
= ip_build_and_send_pkt(skb
, sk
, ireq
->loc_addr
,
502 err
= net_xmit_eval(err
);
510 static void dccp_v4_ctl_send_reset(struct sock
*sk
, struct sk_buff
*rxskb
)
513 struct dccp_hdr
*rxdh
= dccp_hdr(rxskb
), *dh
;
514 const struct iphdr
*rxiph
;
515 const int dccp_hdr_reset_len
= sizeof(struct dccp_hdr
) +
516 sizeof(struct dccp_hdr_ext
) +
517 sizeof(struct dccp_hdr_reset
);
519 struct dst_entry
*dst
;
522 /* Never send a reset in response to a reset. */
523 if (rxdh
->dccph_type
== DCCP_PKT_RESET
)
526 if (((struct rtable
*)rxskb
->dst
)->rt_type
!= RTN_LOCAL
)
529 dst
= dccp_v4_route_skb(dccp_v4_ctl_socket
->sk
, rxskb
);
533 skb
= alloc_skb(dccp_v4_ctl_socket
->sk
->sk_prot
->max_header
,
538 /* Reserve space for headers. */
539 skb_reserve(skb
, dccp_v4_ctl_socket
->sk
->sk_prot
->max_header
);
540 skb
->dst
= dst_clone(dst
);
542 dh
= dccp_zeroed_hdr(skb
, dccp_hdr_reset_len
);
544 /* Build DCCP header and checksum it. */
545 dh
->dccph_type
= DCCP_PKT_RESET
;
546 dh
->dccph_sport
= rxdh
->dccph_dport
;
547 dh
->dccph_dport
= rxdh
->dccph_sport
;
548 dh
->dccph_doff
= dccp_hdr_reset_len
/ 4;
550 dccp_hdr_reset(skb
)->dccph_reset_code
=
551 DCCP_SKB_CB(rxskb
)->dccpd_reset_code
;
553 /* See "8.3.1. Abnormal Termination" in RFC 4340 */
554 if (DCCP_SKB_CB(rxskb
)->dccpd_ack_seq
!= DCCP_PKT_WITHOUT_ACK_SEQ
)
555 dccp_set_seqno(&seqno
, DCCP_SKB_CB(rxskb
)->dccpd_ack_seq
+ 1);
557 dccp_hdr_set_seq(dh
, seqno
);
558 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb
), DCCP_SKB_CB(rxskb
)->dccpd_seq
);
560 dccp_csum_outgoing(skb
);
561 rxiph
= ip_hdr(rxskb
);
562 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, rxiph
->saddr
,
565 bh_lock_sock(dccp_v4_ctl_socket
->sk
);
566 err
= ip_build_and_send_pkt(skb
, dccp_v4_ctl_socket
->sk
,
567 rxiph
->daddr
, rxiph
->saddr
, NULL
);
568 bh_unlock_sock(dccp_v4_ctl_socket
->sk
);
570 if (net_xmit_eval(err
) == 0) {
571 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS
);
572 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS
);
578 static void dccp_v4_reqsk_destructor(struct request_sock
*req
)
580 kfree(inet_rsk(req
)->opt
);
583 static struct request_sock_ops dccp_request_sock_ops __read_mostly
= {
585 .obj_size
= sizeof(struct dccp_request_sock
),
586 .rtx_syn_ack
= dccp_v4_send_response
,
587 .send_ack
= dccp_reqsk_send_ack
,
588 .destructor
= dccp_v4_reqsk_destructor
,
589 .send_reset
= dccp_v4_ctl_send_reset
,
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
);
599 __u8 reset_code
= DCCP_RESET_CODE_TOO_BUSY
;
601 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
602 if (((struct rtable
*)skb
->dst
)->rt_flags
&
603 (RTCF_BROADCAST
| RTCF_MULTICAST
)) {
604 reset_code
= DCCP_RESET_CODE_NO_CONNECTION
;
608 if (dccp_bad_service_code(sk
, service
)) {
609 reset_code
= DCCP_RESET_CODE_BAD_SERVICE_CODE
;
613 * TW buckets are converted to open requests without
614 * limitations, they conserve resources and peer is
615 * evidently real one.
617 if (inet_csk_reqsk_queue_is_full(sk
))
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
626 if (sk_acceptq_is_full(sk
) && inet_csk_reqsk_queue_young(sk
) > 1)
629 req
= reqsk_alloc(&dccp_request_sock_ops
);
633 if (dccp_parse_options(sk
, skb
))
636 dccp_reqsk_init(req
, skb
);
638 if (security_inet_conn_request(sk
, skb
, req
))
641 ireq
= inet_rsk(req
);
642 ireq
->loc_addr
= ip_hdr(skb
)->daddr
;
643 ireq
->rmt_addr
= ip_hdr(skb
)->saddr
;
647 * Step 3: Process LISTEN state
649 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
651 * In fact we defer setting S.GSR, S.SWL, S.SWH to
652 * dccp_create_openreq_child.
654 dreq
= dccp_rsk(req
);
655 dreq
->dreq_isr
= dcb
->dccpd_seq
;
656 dreq
->dreq_iss
= dccp_v4_init_sequence(skb
);
657 dreq
->dreq_service
= service
;
659 if (dccp_v4_send_response(sk
, req
, NULL
))
662 inet_csk_reqsk_queue_hash_add(sk
, req
, DCCP_TIMEOUT_INIT
);
668 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
669 dcb
->dccpd_reset_code
= reset_code
;
673 EXPORT_SYMBOL_GPL(dccp_v4_conn_request
);
675 int dccp_v4_do_rcv(struct sock
*sk
, struct sk_buff
*skb
)
677 struct dccp_hdr
*dh
= dccp_hdr(skb
);
679 if (sk
->sk_state
== DCCP_OPEN
) { /* Fast path */
680 if (dccp_rcv_established(sk
, skb
, dh
, skb
->len
))
686 * Step 3: Process LISTEN state
687 * 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
693 * (* Generate a new socket and switch to that socket *)
694 * Set S := new socket for this port pair
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 *)
702 * Generate Reset(No Connection) unless P.type == Reset
703 * Drop packet and return
705 * NOTE: the check for the packet types is done in
706 * dccp_rcv_state_process
708 if (sk
->sk_state
== DCCP_LISTEN
) {
709 struct sock
*nsk
= dccp_v4_hnd_req(sk
, skb
);
715 if (dccp_child_process(sk
, nsk
, skb
))
721 if (dccp_rcv_state_process(sk
, skb
, dh
, skb
->len
))
726 dccp_v4_ctl_send_reset(sk
, skb
);
732 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv
);
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.
739 int dccp_invalid_packet(struct sk_buff
*skb
)
741 const struct dccp_hdr
*dh
;
744 if (skb
->pkt_type
!= PACKET_HOST
)
747 /* If the packet is shorter than 12 bytes, drop packet and return */
748 if (!pskb_may_pull(skb
, sizeof(struct dccp_hdr
))) {
749 DCCP_WARN("pskb_may_pull failed\n");
755 /* If P.type is not understood, drop packet and return */
756 if (dh
->dccph_type
>= DCCP_PKT_INVALID
) {
757 DCCP_WARN("invalid packet type\n");
762 * If P.Data Offset is too small for packet type, drop packet and return
764 if (dh
->dccph_doff
< dccp_hdr_len(skb
) / sizeof(u32
)) {
765 DCCP_WARN("P.Data Offset(%u) too small\n", dh
->dccph_doff
);
769 * If P.Data Offset is too too large for packet, drop packet and return
771 if (!pskb_may_pull(skb
, dh
->dccph_doff
* sizeof(u32
))) {
772 DCCP_WARN("P.Data Offset(%u) too large\n", dh
->dccph_doff
);
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
780 if (dh
->dccph_type
>= DCCP_PKT_DATA
&&
781 dh
->dccph_type
<= DCCP_PKT_DATAACK
&& dh
->dccph_x
== 0) {
782 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
783 dccp_packet_name(dh
->dccph_type
));
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).
791 cscov
= dccp_csum_coverage(skb
);
792 if (cscov
> skb
->len
) {
793 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
794 dh
->dccph_cscov
, skb
->len
);
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);
805 EXPORT_SYMBOL_GPL(dccp_invalid_packet
);
807 /* this is called when real data arrives */
808 static int dccp_v4_rcv(struct sk_buff
*skb
)
810 const struct dccp_hdr
*dh
;
811 const struct iphdr
*iph
;
815 /* Step 1: Check header basics */
817 if (dccp_invalid_packet(skb
))
821 /* Step 1: If header checksum is incorrect, drop packet and return */
822 if (dccp_v4_csum_finish(skb
, iph
->saddr
, iph
->daddr
)) {
823 DCCP_WARN("dropped packet with invalid checksum\n");
829 DCCP_SKB_CB(skb
)->dccpd_seq
= dccp_hdr_seq(skb
);
830 DCCP_SKB_CB(skb
)->dccpd_type
= dh
->dccph_type
;
832 dccp_pr_debug("%8.8s "
833 "src=%u.%u.%u.%u@%-5d "
834 "dst=%u.%u.%u.%u@%-5d seq=%llu",
835 dccp_packet_name(dh
->dccph_type
),
836 NIPQUAD(iph
->saddr
), ntohs(dh
->dccph_sport
),
837 NIPQUAD(iph
->daddr
), ntohs(dh
->dccph_dport
),
838 (unsigned long long) DCCP_SKB_CB(skb
)->dccpd_seq
);
840 if (dccp_packet_without_ack(skb
)) {
841 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= DCCP_PKT_WITHOUT_ACK_SEQ
;
842 dccp_pr_debug_cat("\n");
844 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= dccp_hdr_ack_seq(skb
);
845 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
846 DCCP_SKB_CB(skb
)->dccpd_ack_seq
);
850 * Look up flow ID in table and get corresponding socket */
851 sk
= __inet_lookup(&dccp_hashinfo
,
852 iph
->saddr
, dh
->dccph_sport
,
853 iph
->daddr
, dh
->dccph_dport
, inet_iif(skb
));
859 dccp_pr_debug("failed to look up flow ID in table and "
860 "get corresponding socket\n");
866 * ... or S.state == TIMEWAIT,
867 * Generate Reset(No Connection) unless P.type == Reset
868 * Drop packet and return
870 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
871 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
872 inet_twsk_put(inet_twsk(sk
));
877 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
878 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
879 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
881 min_cov
= dccp_sk(sk
)->dccps_pcrlen
;
882 if (dh
->dccph_cscov
&& (min_cov
== 0 || dh
->dccph_cscov
< min_cov
)) {
883 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
884 dh
->dccph_cscov
, min_cov
);
885 /* FIXME: "Such packets SHOULD be reported using Data Dropped
886 * options (Section 11.7) with Drop Code 0, Protocol
888 goto discard_and_relse
;
891 if (!xfrm4_policy_check(sk
, XFRM_POLICY_IN
, skb
))
892 goto discard_and_relse
;
895 return sk_receive_skb(sk
, skb
, 1);
898 if (!xfrm4_policy_check(NULL
, XFRM_POLICY_IN
, skb
))
903 * Generate Reset(No Connection) unless P.type == Reset
904 * Drop packet and return
906 if (dh
->dccph_type
!= DCCP_PKT_RESET
) {
907 DCCP_SKB_CB(skb
)->dccpd_reset_code
=
908 DCCP_RESET_CODE_NO_CONNECTION
;
909 dccp_v4_ctl_send_reset(sk
, skb
);
921 static struct inet_connection_sock_af_ops dccp_ipv4_af_ops
= {
922 .queue_xmit
= ip_queue_xmit
,
923 .send_check
= dccp_v4_send_check
,
924 .rebuild_header
= inet_sk_rebuild_header
,
925 .conn_request
= dccp_v4_conn_request
,
926 .syn_recv_sock
= dccp_v4_request_recv_sock
,
927 .net_header_len
= sizeof(struct iphdr
),
928 .setsockopt
= ip_setsockopt
,
929 .getsockopt
= ip_getsockopt
,
930 .addr2sockaddr
= inet_csk_addr2sockaddr
,
931 .sockaddr_len
= sizeof(struct sockaddr_in
),
933 .compat_setsockopt
= compat_ip_setsockopt
,
934 .compat_getsockopt
= compat_ip_getsockopt
,
938 static int dccp_v4_init_sock(struct sock
*sk
)
940 static __u8 dccp_v4_ctl_sock_initialized
;
941 int err
= dccp_init_sock(sk
, dccp_v4_ctl_sock_initialized
);
944 if (unlikely(!dccp_v4_ctl_sock_initialized
))
945 dccp_v4_ctl_sock_initialized
= 1;
946 inet_csk(sk
)->icsk_af_ops
= &dccp_ipv4_af_ops
;
952 static struct timewait_sock_ops dccp_timewait_sock_ops
= {
953 .twsk_obj_size
= sizeof(struct inet_timewait_sock
),
956 static struct proto dccp_v4_prot
= {
958 .owner
= THIS_MODULE
,
960 .connect
= dccp_v4_connect
,
961 .disconnect
= dccp_disconnect
,
963 .init
= dccp_v4_init_sock
,
964 .setsockopt
= dccp_setsockopt
,
965 .getsockopt
= dccp_getsockopt
,
966 .sendmsg
= dccp_sendmsg
,
967 .recvmsg
= dccp_recvmsg
,
968 .backlog_rcv
= dccp_v4_do_rcv
,
970 .unhash
= dccp_unhash
,
971 .accept
= inet_csk_accept
,
972 .get_port
= dccp_v4_get_port
,
973 .shutdown
= dccp_shutdown
,
974 .destroy
= dccp_destroy_sock
,
975 .orphan_count
= &dccp_orphan_count
,
976 .max_header
= MAX_DCCP_HEADER
,
977 .obj_size
= sizeof(struct dccp_sock
),
978 .rsk_prot
= &dccp_request_sock_ops
,
979 .twsk_prot
= &dccp_timewait_sock_ops
,
981 .compat_setsockopt
= compat_dccp_setsockopt
,
982 .compat_getsockopt
= compat_dccp_getsockopt
,
986 static struct net_protocol dccp_v4_protocol
= {
987 .handler
= dccp_v4_rcv
,
988 .err_handler
= dccp_v4_err
,
992 static const struct proto_ops inet_dccp_ops
= {
994 .owner
= THIS_MODULE
,
995 .release
= inet_release
,
997 .connect
= inet_stream_connect
,
998 .socketpair
= sock_no_socketpair
,
999 .accept
= inet_accept
,
1000 .getname
= inet_getname
,
1001 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
1003 .ioctl
= inet_ioctl
,
1004 /* FIXME: work on inet_listen to rename it to sock_common_listen */
1005 .listen
= inet_dccp_listen
,
1006 .shutdown
= inet_shutdown
,
1007 .setsockopt
= sock_common_setsockopt
,
1008 .getsockopt
= sock_common_getsockopt
,
1009 .sendmsg
= inet_sendmsg
,
1010 .recvmsg
= sock_common_recvmsg
,
1011 .mmap
= sock_no_mmap
,
1012 .sendpage
= sock_no_sendpage
,
1013 #ifdef CONFIG_COMPAT
1014 .compat_setsockopt
= compat_sock_common_setsockopt
,
1015 .compat_getsockopt
= compat_sock_common_getsockopt
,
1019 static struct inet_protosw dccp_v4_protosw
= {
1021 .protocol
= IPPROTO_DCCP
,
1022 .prot
= &dccp_v4_prot
,
1023 .ops
= &inet_dccp_ops
,
1026 .flags
= INET_PROTOSW_ICSK
,
1029 static int __init
dccp_v4_init(void)
1031 int err
= proto_register(&dccp_v4_prot
, 1);
1036 err
= inet_add_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1038 goto out_proto_unregister
;
1040 inet_register_protosw(&dccp_v4_protosw
);
1042 err
= inet_csk_ctl_sock_create(&dccp_v4_ctl_socket
, PF_INET
,
1043 SOCK_DCCP
, IPPROTO_DCCP
);
1045 goto out_unregister_protosw
;
1048 out_unregister_protosw
:
1049 inet_unregister_protosw(&dccp_v4_protosw
);
1050 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1051 out_proto_unregister
:
1052 proto_unregister(&dccp_v4_prot
);
1056 static void __exit
dccp_v4_exit(void)
1058 inet_unregister_protosw(&dccp_v4_protosw
);
1059 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1060 proto_unregister(&dccp_v4_prot
);
1063 module_init(dccp_v4_init
);
1064 module_exit(dccp_v4_exit
);
1067 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1068 * values directly, Also cover the case where the protocol is not specified,
1069 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1071 MODULE_ALIAS("net-pf-" __stringify(PF_INET
) "-proto-33-type-6");
1072 MODULE_ALIAS("net-pf-" __stringify(PF_INET
) "-proto-0-type-6");
1073 MODULE_LICENSE("GPL");
1074 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1075 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");