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>
36 * The per-net dccp.v4_ctl_sk socket is used for responding to
37 * the Out-of-the-blue (OOTB) packets. A control sock will be created
38 * for this socket at the initialization time.
41 int dccp_v4_connect(struct sock
*sk
, struct sockaddr
*uaddr
, int addr_len
)
43 const struct sockaddr_in
*usin
= (struct sockaddr_in
*)uaddr
;
44 struct inet_sock
*inet
= inet_sk(sk
);
45 struct dccp_sock
*dp
= dccp_sk(sk
);
46 __be16 orig_sport
, orig_dport
;
47 __be32 daddr
, nexthop
;
51 struct ip_options_rcu
*inet_opt
;
53 dp
->dccps_role
= DCCP_ROLE_CLIENT
;
55 if (addr_len
< sizeof(struct sockaddr_in
))
58 if (usin
->sin_family
!= AF_INET
)
61 nexthop
= daddr
= usin
->sin_addr
.s_addr
;
63 inet_opt
= rcu_dereference_protected(inet
->inet_opt
,
64 sock_owned_by_user(sk
));
65 if (inet_opt
!= NULL
&& inet_opt
->opt
.srr
) {
68 nexthop
= inet_opt
->opt
.faddr
;
71 orig_sport
= inet
->inet_sport
;
72 orig_dport
= usin
->sin_port
;
73 fl4
= &inet
->cork
.fl
.u
.ip4
;
74 rt
= ip_route_connect(fl4
, nexthop
, inet
->inet_saddr
,
75 RT_CONN_FLAGS(sk
), sk
->sk_bound_dev_if
,
77 orig_sport
, orig_dport
, sk
, true);
81 if (rt
->rt_flags
& (RTCF_MULTICAST
| RTCF_BROADCAST
)) {
86 if (inet_opt
== NULL
|| !inet_opt
->opt
.srr
)
89 if (inet
->inet_saddr
== 0)
90 inet
->inet_saddr
= fl4
->saddr
;
91 inet
->inet_rcv_saddr
= inet
->inet_saddr
;
93 inet
->inet_dport
= usin
->sin_port
;
94 inet
->inet_daddr
= 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
);
116 /* OK, now commit destination to socket. */
117 sk_setup_caps(sk
, &rt
->dst
);
119 dp
->dccps_iss
= secure_dccp_sequence_number(inet
->inet_saddr
,
123 inet
->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;
138 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 /* 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 u8 offset
= iph
->ihl
<< 2;
212 const struct dccp_hdr
*dh
= (struct dccp_hdr
*)(skb
->data
+ offset
);
213 struct dccp_sock
*dp
;
214 struct inet_sock
*inet
;
215 const int type
= icmp_hdr(skb
)->type
;
216 const int code
= icmp_hdr(skb
)->code
;
220 struct net
*net
= dev_net(skb
->dev
);
222 if (skb
->len
< offset
+ sizeof(*dh
) ||
223 skb
->len
< offset
+ __dccp_basic_hdr_len(dh
)) {
224 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
228 sk
= inet_lookup(net
, &dccp_hashinfo
,
229 iph
->daddr
, dh
->dccph_dport
,
230 iph
->saddr
, dh
->dccph_sport
, inet_iif(skb
));
232 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
236 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
237 inet_twsk_put(inet_twsk(sk
));
242 /* If too many ICMPs get dropped on busy
243 * servers this needs to be solved differently.
245 if (sock_owned_by_user(sk
))
246 NET_INC_STATS_BH(net
, LINUX_MIB_LOCKDROPPEDICMPS
);
248 if (sk
->sk_state
== DCCP_CLOSED
)
252 seq
= dccp_hdr_seq(dh
);
253 if ((1 << sk
->sk_state
) & ~(DCCPF_REQUESTING
| DCCPF_LISTEN
) &&
254 !between48(seq
, dp
->dccps_awl
, dp
->dccps_awh
)) {
255 NET_INC_STATS_BH(net
, LINUX_MIB_OUTOFWINDOWICMPS
);
260 case ICMP_SOURCE_QUENCH
:
261 /* Just silently ignore these. */
263 case ICMP_PARAMETERPROB
:
266 case ICMP_DEST_UNREACH
:
267 if (code
> NR_ICMP_UNREACH
)
270 if (code
== ICMP_FRAG_NEEDED
) { /* PMTU discovery (RFC1191) */
271 if (!sock_owned_by_user(sk
))
272 dccp_do_pmtu_discovery(sk
, iph
, info
);
276 err
= icmp_err_convert
[code
].errno
;
278 case ICMP_TIME_EXCEEDED
:
285 switch (sk
->sk_state
) {
286 struct request_sock
*req
, **prev
;
288 if (sock_owned_by_user(sk
))
290 req
= inet_csk_search_req(sk
, &prev
, dh
->dccph_dport
,
291 iph
->daddr
, iph
->saddr
);
296 * ICMPs are not backlogged, hence we cannot get an established
301 if (seq
!= dccp_rsk(req
)->dreq_iss
) {
302 NET_INC_STATS_BH(net
, LINUX_MIB_OUTOFWINDOWICMPS
);
306 * Still in RESPOND, just remove it silently.
307 * There is no good way to pass the error to the newly
308 * created socket, and POSIX does not want network
309 * errors returned from accept().
311 inet_csk_reqsk_queue_drop(sk
, req
, prev
);
314 case DCCP_REQUESTING
:
316 if (!sock_owned_by_user(sk
)) {
317 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
320 sk
->sk_error_report(sk
);
324 sk
->sk_err_soft
= err
;
328 /* If we've already connected we will keep trying
329 * until we time out, or the user gives up.
331 * rfc1122 4.2.3.9 allows to consider as hard errors
332 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
333 * but it is obsoleted by pmtu discovery).
335 * Note, that in modern internet, where routing is unreliable
336 * and in each dark corner broken firewalls sit, sending random
337 * errors ordered by their masters even this two messages finally lose
338 * their original sense (even Linux sends invalid PORT_UNREACHs)
340 * Now we are in compliance with RFCs.
345 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
347 sk
->sk_error_report(sk
);
348 } else /* Only an error on timeout */
349 sk
->sk_err_soft
= err
;
355 static inline __sum16
dccp_v4_csum_finish(struct sk_buff
*skb
,
356 __be32 src
, __be32 dst
)
358 return csum_tcpudp_magic(src
, dst
, skb
->len
, IPPROTO_DCCP
, skb
->csum
);
361 void dccp_v4_send_check(struct sock
*sk
, struct sk_buff
*skb
)
363 const struct inet_sock
*inet
= inet_sk(sk
);
364 struct dccp_hdr
*dh
= dccp_hdr(skb
);
366 dccp_csum_outgoing(skb
);
367 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
,
372 EXPORT_SYMBOL_GPL(dccp_v4_send_check
);
374 static inline u64
dccp_v4_init_sequence(const struct sk_buff
*skb
)
376 return secure_dccp_sequence_number(ip_hdr(skb
)->daddr
,
378 dccp_hdr(skb
)->dccph_dport
,
379 dccp_hdr(skb
)->dccph_sport
);
383 * The three way handshake has completed - we got a valid ACK or DATAACK -
384 * now create the new socket.
386 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
388 struct sock
*dccp_v4_request_recv_sock(struct sock
*sk
, struct sk_buff
*skb
,
389 struct request_sock
*req
,
390 struct dst_entry
*dst
)
392 struct inet_request_sock
*ireq
;
393 struct inet_sock
*newinet
;
396 if (sk_acceptq_is_full(sk
))
399 newsk
= dccp_create_openreq_child(sk
, req
, skb
);
403 newinet
= inet_sk(newsk
);
404 ireq
= inet_rsk(req
);
405 newinet
->inet_daddr
= ireq
->rmt_addr
;
406 newinet
->inet_rcv_saddr
= ireq
->loc_addr
;
407 newinet
->inet_saddr
= ireq
->loc_addr
;
408 newinet
->inet_opt
= ireq
->opt
;
410 newinet
->mc_index
= inet_iif(skb
);
411 newinet
->mc_ttl
= ip_hdr(skb
)->ttl
;
412 newinet
->inet_id
= jiffies
;
414 if (dst
== NULL
&& (dst
= inet_csk_route_child_sock(sk
, newsk
, req
)) == NULL
)
417 sk_setup_caps(newsk
, dst
);
419 dccp_sync_mss(newsk
, dst_mtu(dst
));
421 if (__inet_inherit_port(sk
, newsk
) < 0)
423 __inet_hash_nolisten(newsk
, NULL
);
428 NET_INC_STATS_BH(sock_net(sk
), LINUX_MIB_LISTENOVERFLOWS
);
432 NET_INC_STATS_BH(sock_net(sk
), LINUX_MIB_LISTENDROPS
);
439 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock
);
441 static struct sock
*dccp_v4_hnd_req(struct sock
*sk
, struct sk_buff
*skb
)
443 const struct dccp_hdr
*dh
= dccp_hdr(skb
);
444 const struct iphdr
*iph
= ip_hdr(skb
);
446 struct request_sock
**prev
;
447 /* Find possible connection requests. */
448 struct request_sock
*req
= inet_csk_search_req(sk
, &prev
,
450 iph
->saddr
, iph
->daddr
);
452 return dccp_check_req(sk
, skb
, req
, prev
);
454 nsk
= inet_lookup_established(sock_net(sk
), &dccp_hashinfo
,
455 iph
->saddr
, dh
->dccph_sport
,
456 iph
->daddr
, dh
->dccph_dport
,
459 if (nsk
->sk_state
!= DCCP_TIME_WAIT
) {
463 inet_twsk_put(inet_twsk(nsk
));
470 static struct dst_entry
* dccp_v4_route_skb(struct net
*net
, struct sock
*sk
,
474 struct flowi4 fl4
= {
475 .flowi4_oif
= skb_rtable(skb
)->rt_iif
,
476 .daddr
= ip_hdr(skb
)->saddr
,
477 .saddr
= ip_hdr(skb
)->daddr
,
478 .flowi4_tos
= RT_CONN_FLAGS(sk
),
479 .flowi4_proto
= sk
->sk_protocol
,
480 .fl4_sport
= dccp_hdr(skb
)->dccph_dport
,
481 .fl4_dport
= dccp_hdr(skb
)->dccph_sport
,
484 security_skb_classify_flow(skb
, flowi4_to_flowi(&fl4
));
485 rt
= ip_route_output_flow(net
, &fl4
, sk
);
487 IP_INC_STATS_BH(net
, IPSTATS_MIB_OUTNOROUTES
);
494 static int dccp_v4_send_response(struct sock
*sk
, struct request_sock
*req
,
495 struct request_values
*rv_unused
)
499 struct dst_entry
*dst
;
502 dst
= inet_csk_route_req(sk
, &fl4
, req
);
506 skb
= dccp_make_response(sk
, dst
, req
);
508 const struct inet_request_sock
*ireq
= inet_rsk(req
);
509 struct dccp_hdr
*dh
= dccp_hdr(skb
);
511 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, ireq
->loc_addr
,
513 err
= ip_build_and_send_pkt(skb
, sk
, ireq
->loc_addr
,
516 err
= net_xmit_eval(err
);
524 static void dccp_v4_ctl_send_reset(struct sock
*sk
, struct sk_buff
*rxskb
)
527 const struct iphdr
*rxiph
;
529 struct dst_entry
*dst
;
530 struct net
*net
= dev_net(skb_dst(rxskb
)->dev
);
531 struct sock
*ctl_sk
= net
->dccp
.v4_ctl_sk
;
533 /* Never send a reset in response to a reset. */
534 if (dccp_hdr(rxskb
)->dccph_type
== DCCP_PKT_RESET
)
537 if (skb_rtable(rxskb
)->rt_type
!= RTN_LOCAL
)
540 dst
= dccp_v4_route_skb(net
, ctl_sk
, rxskb
);
544 skb
= dccp_ctl_make_reset(ctl_sk
, rxskb
);
548 rxiph
= ip_hdr(rxskb
);
549 dccp_hdr(skb
)->dccph_checksum
= dccp_v4_csum_finish(skb
, rxiph
->saddr
,
551 skb_dst_set(skb
, dst_clone(dst
));
553 bh_lock_sock(ctl_sk
);
554 err
= ip_build_and_send_pkt(skb
, ctl_sk
,
555 rxiph
->daddr
, rxiph
->saddr
, NULL
);
556 bh_unlock_sock(ctl_sk
);
558 if (net_xmit_eval(err
) == 0) {
559 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS
);
560 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS
);
566 static void dccp_v4_reqsk_destructor(struct request_sock
*req
)
568 dccp_feat_list_purge(&dccp_rsk(req
)->dreq_featneg
);
569 kfree(inet_rsk(req
)->opt
);
572 static struct request_sock_ops dccp_request_sock_ops __read_mostly
= {
574 .obj_size
= sizeof(struct dccp_request_sock
),
575 .rtx_syn_ack
= dccp_v4_send_response
,
576 .send_ack
= dccp_reqsk_send_ack
,
577 .destructor
= dccp_v4_reqsk_destructor
,
578 .send_reset
= dccp_v4_ctl_send_reset
,
581 int dccp_v4_conn_request(struct sock
*sk
, struct sk_buff
*skb
)
583 struct inet_request_sock
*ireq
;
584 struct request_sock
*req
;
585 struct dccp_request_sock
*dreq
;
586 const __be32 service
= dccp_hdr_request(skb
)->dccph_req_service
;
587 struct dccp_skb_cb
*dcb
= DCCP_SKB_CB(skb
);
589 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
590 if (skb_rtable(skb
)->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
))
591 return 0; /* discard, don't send a reset here */
593 if (dccp_bad_service_code(sk
, service
)) {
594 dcb
->dccpd_reset_code
= DCCP_RESET_CODE_BAD_SERVICE_CODE
;
598 * TW buckets are converted to open requests without
599 * limitations, they conserve resources and peer is
600 * evidently real one.
602 dcb
->dccpd_reset_code
= DCCP_RESET_CODE_TOO_BUSY
;
603 if (inet_csk_reqsk_queue_is_full(sk
))
607 * Accept backlog is full. If we have already queued enough
608 * of warm entries in syn queue, drop request. It is better than
609 * clogging syn queue with openreqs with exponentially increasing
612 if (sk_acceptq_is_full(sk
) && inet_csk_reqsk_queue_young(sk
) > 1)
615 req
= inet_reqsk_alloc(&dccp_request_sock_ops
);
619 if (dccp_reqsk_init(req
, dccp_sk(sk
), skb
))
622 dreq
= dccp_rsk(req
);
623 if (dccp_parse_options(sk
, dreq
, skb
))
626 if (security_inet_conn_request(sk
, skb
, req
))
629 ireq
= inet_rsk(req
);
630 ireq
->loc_addr
= ip_hdr(skb
)->daddr
;
631 ireq
->rmt_addr
= ip_hdr(skb
)->saddr
;
634 * Step 3: Process LISTEN state
636 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
638 * In fact we defer setting S.GSR, S.SWL, S.SWH to
639 * dccp_create_openreq_child.
641 dreq
->dreq_isr
= dcb
->dccpd_seq
;
642 dreq
->dreq_iss
= dccp_v4_init_sequence(skb
);
643 dreq
->dreq_service
= service
;
645 if (dccp_v4_send_response(sk
, req
, NULL
))
648 inet_csk_reqsk_queue_hash_add(sk
, req
, DCCP_TIMEOUT_INIT
);
654 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
658 EXPORT_SYMBOL_GPL(dccp_v4_conn_request
);
660 int dccp_v4_do_rcv(struct sock
*sk
, struct sk_buff
*skb
)
662 struct dccp_hdr
*dh
= dccp_hdr(skb
);
664 if (sk
->sk_state
== DCCP_OPEN
) { /* Fast path */
665 if (dccp_rcv_established(sk
, skb
, dh
, skb
->len
))
671 * Step 3: Process LISTEN state
672 * If P.type == Request or P contains a valid Init Cookie option,
673 * (* Must scan the packet's options to check for Init
674 * Cookies. Only Init Cookies are processed here,
675 * however; other options are processed in Step 8. This
676 * scan need only be performed if the endpoint uses Init
678 * (* Generate a new socket and switch to that socket *)
679 * Set S := new socket for this port pair
681 * Choose S.ISS (initial seqno) or set from Init Cookies
682 * Initialize S.GAR := S.ISS
683 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
684 * Continue with S.state == RESPOND
685 * (* A Response packet will be generated in Step 11 *)
687 * Generate Reset(No Connection) unless P.type == Reset
688 * Drop packet and return
690 * NOTE: the check for the packet types is done in
691 * dccp_rcv_state_process
693 if (sk
->sk_state
== DCCP_LISTEN
) {
694 struct sock
*nsk
= dccp_v4_hnd_req(sk
, skb
);
700 if (dccp_child_process(sk
, nsk
, skb
))
706 if (dccp_rcv_state_process(sk
, skb
, dh
, skb
->len
))
711 dccp_v4_ctl_send_reset(sk
, skb
);
717 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv
);
720 * dccp_invalid_packet - check for malformed packets
721 * Implements RFC 4340, 8.5: Step 1: Check header basics
722 * Packets that fail these checks are ignored and do not receive Resets.
724 int dccp_invalid_packet(struct sk_buff
*skb
)
726 const struct dccp_hdr
*dh
;
729 if (skb
->pkt_type
!= PACKET_HOST
)
732 /* If the packet is shorter than 12 bytes, drop packet and return */
733 if (!pskb_may_pull(skb
, sizeof(struct dccp_hdr
))) {
734 DCCP_WARN("pskb_may_pull failed\n");
740 /* If P.type is not understood, drop packet and return */
741 if (dh
->dccph_type
>= DCCP_PKT_INVALID
) {
742 DCCP_WARN("invalid packet type\n");
747 * If P.Data Offset is too small for packet type, drop packet and return
749 if (dh
->dccph_doff
< dccp_hdr_len(skb
) / sizeof(u32
)) {
750 DCCP_WARN("P.Data Offset(%u) too small\n", dh
->dccph_doff
);
754 * If P.Data Offset is too too large for packet, drop packet and return
756 if (!pskb_may_pull(skb
, dh
->dccph_doff
* sizeof(u32
))) {
757 DCCP_WARN("P.Data Offset(%u) too large\n", dh
->dccph_doff
);
762 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
763 * has short sequence numbers), drop packet and return
765 if ((dh
->dccph_type
< DCCP_PKT_DATA
||
766 dh
->dccph_type
> DCCP_PKT_DATAACK
) && dh
->dccph_x
== 0) {
767 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
768 dccp_packet_name(dh
->dccph_type
));
773 * If P.CsCov is too large for the packet size, drop packet and return.
774 * This must come _before_ checksumming (not as RFC 4340 suggests).
776 cscov
= dccp_csum_coverage(skb
);
777 if (cscov
> skb
->len
) {
778 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
779 dh
->dccph_cscov
, skb
->len
);
783 /* If header checksum is incorrect, drop packet and return.
784 * (This step is completed in the AF-dependent functions.) */
785 skb
->csum
= skb_checksum(skb
, 0, cscov
, 0);
790 EXPORT_SYMBOL_GPL(dccp_invalid_packet
);
792 /* this is called when real data arrives */
793 static int dccp_v4_rcv(struct sk_buff
*skb
)
795 const struct dccp_hdr
*dh
;
796 const struct iphdr
*iph
;
800 /* Step 1: Check header basics */
802 if (dccp_invalid_packet(skb
))
806 /* Step 1: If header checksum is incorrect, drop packet and return */
807 if (dccp_v4_csum_finish(skb
, iph
->saddr
, iph
->daddr
)) {
808 DCCP_WARN("dropped packet with invalid checksum\n");
814 DCCP_SKB_CB(skb
)->dccpd_seq
= dccp_hdr_seq(dh
);
815 DCCP_SKB_CB(skb
)->dccpd_type
= dh
->dccph_type
;
817 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
818 dccp_packet_name(dh
->dccph_type
),
819 &iph
->saddr
, ntohs(dh
->dccph_sport
),
820 &iph
->daddr
, ntohs(dh
->dccph_dport
),
821 (unsigned long long) DCCP_SKB_CB(skb
)->dccpd_seq
);
823 if (dccp_packet_without_ack(skb
)) {
824 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= DCCP_PKT_WITHOUT_ACK_SEQ
;
825 dccp_pr_debug_cat("\n");
827 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= dccp_hdr_ack_seq(skb
);
828 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
829 DCCP_SKB_CB(skb
)->dccpd_ack_seq
);
833 * Look up flow ID in table and get corresponding socket */
834 sk
= __inet_lookup_skb(&dccp_hashinfo
, skb
,
835 dh
->dccph_sport
, dh
->dccph_dport
);
841 dccp_pr_debug("failed to look up flow ID in table and "
842 "get corresponding socket\n");
848 * ... or S.state == TIMEWAIT,
849 * Generate Reset(No Connection) unless P.type == Reset
850 * Drop packet and return
852 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
853 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
854 inet_twsk_put(inet_twsk(sk
));
859 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
860 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
861 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
863 min_cov
= dccp_sk(sk
)->dccps_pcrlen
;
864 if (dh
->dccph_cscov
&& (min_cov
== 0 || dh
->dccph_cscov
< min_cov
)) {
865 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
866 dh
->dccph_cscov
, min_cov
);
867 /* FIXME: "Such packets SHOULD be reported using Data Dropped
868 * options (Section 11.7) with Drop Code 0, Protocol
870 goto discard_and_relse
;
873 if (!xfrm4_policy_check(sk
, XFRM_POLICY_IN
, skb
))
874 goto discard_and_relse
;
877 return sk_receive_skb(sk
, skb
, 1);
880 if (!xfrm4_policy_check(NULL
, XFRM_POLICY_IN
, skb
))
885 * Generate Reset(No Connection) unless P.type == Reset
886 * Drop packet and return
888 if (dh
->dccph_type
!= DCCP_PKT_RESET
) {
889 DCCP_SKB_CB(skb
)->dccpd_reset_code
=
890 DCCP_RESET_CODE_NO_CONNECTION
;
891 dccp_v4_ctl_send_reset(sk
, skb
);
903 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops
= {
904 .queue_xmit
= ip_queue_xmit
,
905 .send_check
= dccp_v4_send_check
,
906 .rebuild_header
= inet_sk_rebuild_header
,
907 .conn_request
= dccp_v4_conn_request
,
908 .syn_recv_sock
= dccp_v4_request_recv_sock
,
909 .net_header_len
= sizeof(struct iphdr
),
910 .setsockopt
= ip_setsockopt
,
911 .getsockopt
= ip_getsockopt
,
912 .addr2sockaddr
= inet_csk_addr2sockaddr
,
913 .sockaddr_len
= sizeof(struct sockaddr_in
),
914 .bind_conflict
= inet_csk_bind_conflict
,
916 .compat_setsockopt
= compat_ip_setsockopt
,
917 .compat_getsockopt
= compat_ip_getsockopt
,
921 static int dccp_v4_init_sock(struct sock
*sk
)
923 static __u8 dccp_v4_ctl_sock_initialized
;
924 int err
= dccp_init_sock(sk
, dccp_v4_ctl_sock_initialized
);
927 if (unlikely(!dccp_v4_ctl_sock_initialized
))
928 dccp_v4_ctl_sock_initialized
= 1;
929 inet_csk(sk
)->icsk_af_ops
= &dccp_ipv4_af_ops
;
935 static struct timewait_sock_ops dccp_timewait_sock_ops
= {
936 .twsk_obj_size
= sizeof(struct inet_timewait_sock
),
939 static struct proto dccp_v4_prot
= {
941 .owner
= THIS_MODULE
,
943 .connect
= dccp_v4_connect
,
944 .disconnect
= dccp_disconnect
,
946 .init
= dccp_v4_init_sock
,
947 .setsockopt
= dccp_setsockopt
,
948 .getsockopt
= dccp_getsockopt
,
949 .sendmsg
= dccp_sendmsg
,
950 .recvmsg
= dccp_recvmsg
,
951 .backlog_rcv
= dccp_v4_do_rcv
,
953 .unhash
= inet_unhash
,
954 .accept
= inet_csk_accept
,
955 .get_port
= inet_csk_get_port
,
956 .shutdown
= dccp_shutdown
,
957 .destroy
= dccp_destroy_sock
,
958 .orphan_count
= &dccp_orphan_count
,
959 .max_header
= MAX_DCCP_HEADER
,
960 .obj_size
= sizeof(struct dccp_sock
),
961 .slab_flags
= SLAB_DESTROY_BY_RCU
,
962 .rsk_prot
= &dccp_request_sock_ops
,
963 .twsk_prot
= &dccp_timewait_sock_ops
,
964 .h
.hashinfo
= &dccp_hashinfo
,
966 .compat_setsockopt
= compat_dccp_setsockopt
,
967 .compat_getsockopt
= compat_dccp_getsockopt
,
971 static const struct net_protocol dccp_v4_protocol
= {
972 .handler
= dccp_v4_rcv
,
973 .err_handler
= dccp_v4_err
,
978 static const struct proto_ops inet_dccp_ops
= {
980 .owner
= THIS_MODULE
,
981 .release
= inet_release
,
983 .connect
= inet_stream_connect
,
984 .socketpair
= sock_no_socketpair
,
985 .accept
= inet_accept
,
986 .getname
= inet_getname
,
987 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
990 /* FIXME: work on inet_listen to rename it to sock_common_listen */
991 .listen
= inet_dccp_listen
,
992 .shutdown
= inet_shutdown
,
993 .setsockopt
= sock_common_setsockopt
,
994 .getsockopt
= sock_common_getsockopt
,
995 .sendmsg
= inet_sendmsg
,
996 .recvmsg
= sock_common_recvmsg
,
997 .mmap
= sock_no_mmap
,
998 .sendpage
= sock_no_sendpage
,
1000 .compat_setsockopt
= compat_sock_common_setsockopt
,
1001 .compat_getsockopt
= compat_sock_common_getsockopt
,
1005 static struct inet_protosw dccp_v4_protosw
= {
1007 .protocol
= IPPROTO_DCCP
,
1008 .prot
= &dccp_v4_prot
,
1009 .ops
= &inet_dccp_ops
,
1011 .flags
= INET_PROTOSW_ICSK
,
1014 static int __net_init
dccp_v4_init_net(struct net
*net
)
1016 if (dccp_hashinfo
.bhash
== NULL
)
1017 return -ESOCKTNOSUPPORT
;
1019 return inet_ctl_sock_create(&net
->dccp
.v4_ctl_sk
, PF_INET
,
1020 SOCK_DCCP
, IPPROTO_DCCP
, net
);
1023 static void __net_exit
dccp_v4_exit_net(struct net
*net
)
1025 inet_ctl_sock_destroy(net
->dccp
.v4_ctl_sk
);
1028 static struct pernet_operations dccp_v4_ops
= {
1029 .init
= dccp_v4_init_net
,
1030 .exit
= dccp_v4_exit_net
,
1033 static int __init
dccp_v4_init(void)
1035 int err
= proto_register(&dccp_v4_prot
, 1);
1040 err
= inet_add_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1042 goto out_proto_unregister
;
1044 inet_register_protosw(&dccp_v4_protosw
);
1046 err
= register_pernet_subsys(&dccp_v4_ops
);
1048 goto out_destroy_ctl_sock
;
1051 out_destroy_ctl_sock
:
1052 inet_unregister_protosw(&dccp_v4_protosw
);
1053 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1054 out_proto_unregister
:
1055 proto_unregister(&dccp_v4_prot
);
1059 static void __exit
dccp_v4_exit(void)
1061 unregister_pernet_subsys(&dccp_v4_ops
);
1062 inet_unregister_protosw(&dccp_v4_protosw
);
1063 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1064 proto_unregister(&dccp_v4_prot
);
1067 module_init(dccp_v4_init
);
1068 module_exit(dccp_v4_exit
);
1071 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1072 * values directly, Also cover the case where the protocol is not specified,
1073 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1075 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET
, 33, 6);
1076 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET
, 0, 6);
1077 MODULE_LICENSE("GPL");
1078 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1079 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");