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 struct inet_sock
*inet
= inet_sk(sk
);
44 struct dccp_sock
*dp
= dccp_sk(sk
);
45 const struct sockaddr_in
*usin
= (struct sockaddr_in
*)uaddr
;
46 __be16 orig_sport
, orig_dport
;
48 __be32 daddr
, nexthop
;
52 dp
->dccps_role
= DCCP_ROLE_CLIENT
;
54 if (addr_len
< sizeof(struct sockaddr_in
))
57 if (usin
->sin_family
!= AF_INET
)
60 nexthop
= daddr
= usin
->sin_addr
.s_addr
;
61 if (inet
->opt
!= NULL
&& inet
->opt
->srr
) {
64 nexthop
= inet
->opt
->faddr
;
67 orig_sport
= inet
->inet_sport
;
68 orig_dport
= usin
->sin_port
;
69 tmp
= ip_route_connect(&rt
, nexthop
, inet
->inet_saddr
,
70 RT_CONN_FLAGS(sk
), sk
->sk_bound_dev_if
,
72 orig_sport
, orig_dport
, sk
, true);
76 if (rt
->rt_flags
& (RTCF_MULTICAST
| RTCF_BROADCAST
)) {
81 if (inet
->opt
== NULL
|| !inet
->opt
->srr
)
84 if (inet
->inet_saddr
== 0)
85 inet
->inet_saddr
= rt
->rt_src
;
86 inet
->inet_rcv_saddr
= inet
->inet_saddr
;
88 inet
->inet_dport
= usin
->sin_port
;
89 inet
->inet_daddr
= daddr
;
91 inet_csk(sk
)->icsk_ext_hdr_len
= 0;
92 if (inet
->opt
!= NULL
)
93 inet_csk(sk
)->icsk_ext_hdr_len
= inet
->opt
->optlen
;
95 * Socket identity is still unknown (sport may be zero).
96 * However we set state to DCCP_REQUESTING and not releasing socket
97 * lock select source port, enter ourselves into the hash tables and
98 * complete initialization after this.
100 dccp_set_state(sk
, DCCP_REQUESTING
);
101 err
= inet_hash_connect(&dccp_death_row
, sk
);
105 err
= ip_route_newports(&rt
, IPPROTO_DCCP
,
106 orig_sport
, orig_dport
,
107 inet
->inet_sport
, inet
->inet_dport
, sk
);
111 /* OK, now commit destination to socket. */
112 sk_setup_caps(sk
, &rt
->dst
);
114 dp
->dccps_iss
= secure_dccp_sequence_number(inet
->inet_saddr
,
118 inet
->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;
133 inet
->inet_dport
= 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 u8 offset
= iph
->ihl
<< 2;
207 const struct dccp_hdr
*dh
= (struct dccp_hdr
*)(skb
->data
+ offset
);
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
;
215 struct net
*net
= dev_net(skb
->dev
);
217 if (skb
->len
< offset
+ sizeof(*dh
) ||
218 skb
->len
< offset
+ __dccp_basic_hdr_len(dh
)) {
219 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
223 sk
= inet_lookup(net
, &dccp_hashinfo
,
224 iph
->daddr
, dh
->dccph_dport
,
225 iph
->saddr
, dh
->dccph_sport
, inet_iif(skb
));
227 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
231 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
232 inet_twsk_put(inet_twsk(sk
));
237 /* If too many ICMPs get dropped on busy
238 * servers this needs to be solved differently.
240 if (sock_owned_by_user(sk
))
241 NET_INC_STATS_BH(net
, LINUX_MIB_LOCKDROPPEDICMPS
);
243 if (sk
->sk_state
== DCCP_CLOSED
)
247 seq
= dccp_hdr_seq(dh
);
248 if ((1 << sk
->sk_state
) & ~(DCCPF_REQUESTING
| DCCPF_LISTEN
) &&
249 !between48(seq
, dp
->dccps_awl
, dp
->dccps_awh
)) {
250 NET_INC_STATS_BH(net
, LINUX_MIB_OUTOFWINDOWICMPS
);
255 case ICMP_SOURCE_QUENCH
:
256 /* Just silently ignore these. */
258 case ICMP_PARAMETERPROB
:
261 case ICMP_DEST_UNREACH
:
262 if (code
> NR_ICMP_UNREACH
)
265 if (code
== ICMP_FRAG_NEEDED
) { /* PMTU discovery (RFC1191) */
266 if (!sock_owned_by_user(sk
))
267 dccp_do_pmtu_discovery(sk
, iph
, info
);
271 err
= icmp_err_convert
[code
].errno
;
273 case ICMP_TIME_EXCEEDED
:
280 switch (sk
->sk_state
) {
281 struct request_sock
*req
, **prev
;
283 if (sock_owned_by_user(sk
))
285 req
= inet_csk_search_req(sk
, &prev
, dh
->dccph_dport
,
286 iph
->daddr
, iph
->saddr
);
291 * ICMPs are not backlogged, hence we cannot get an established
296 if (seq
!= dccp_rsk(req
)->dreq_iss
) {
297 NET_INC_STATS_BH(net
, LINUX_MIB_OUTOFWINDOWICMPS
);
301 * Still in RESPOND, just remove it silently.
302 * There is no good way to pass the error to the newly
303 * created socket, and POSIX does not want network
304 * errors returned from accept().
306 inet_csk_reqsk_queue_drop(sk
, req
, prev
);
309 case DCCP_REQUESTING
:
311 if (!sock_owned_by_user(sk
)) {
312 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
315 sk
->sk_error_report(sk
);
319 sk
->sk_err_soft
= err
;
323 /* If we've already connected we will keep trying
324 * until we time out, or the user gives up.
326 * rfc1122 4.2.3.9 allows to consider as hard errors
327 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
328 * but it is obsoleted by pmtu discovery).
330 * Note, that in modern internet, where routing is unreliable
331 * and in each dark corner broken firewalls sit, sending random
332 * errors ordered by their masters even this two messages finally lose
333 * their original sense (even Linux sends invalid PORT_UNREACHs)
335 * Now we are in compliance with RFCs.
340 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
342 sk
->sk_error_report(sk
);
343 } else /* Only an error on timeout */
344 sk
->sk_err_soft
= err
;
350 static inline __sum16
dccp_v4_csum_finish(struct sk_buff
*skb
,
351 __be32 src
, __be32 dst
)
353 return csum_tcpudp_magic(src
, dst
, skb
->len
, IPPROTO_DCCP
, skb
->csum
);
356 void dccp_v4_send_check(struct sock
*sk
, struct sk_buff
*skb
)
358 const struct inet_sock
*inet
= inet_sk(sk
);
359 struct dccp_hdr
*dh
= dccp_hdr(skb
);
361 dccp_csum_outgoing(skb
);
362 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
,
367 EXPORT_SYMBOL_GPL(dccp_v4_send_check
);
369 static inline u64
dccp_v4_init_sequence(const struct sk_buff
*skb
)
371 return secure_dccp_sequence_number(ip_hdr(skb
)->daddr
,
373 dccp_hdr(skb
)->dccph_dport
,
374 dccp_hdr(skb
)->dccph_sport
);
378 * The three way handshake has completed - we got a valid ACK or DATAACK -
379 * now create the new socket.
381 * This is the equivalent of TCP's tcp_v4_syn_recv_sock
383 struct sock
*dccp_v4_request_recv_sock(struct sock
*sk
, struct sk_buff
*skb
,
384 struct request_sock
*req
,
385 struct dst_entry
*dst
)
387 struct inet_request_sock
*ireq
;
388 struct inet_sock
*newinet
;
391 if (sk_acceptq_is_full(sk
))
394 if (dst
== NULL
&& (dst
= inet_csk_route_req(sk
, req
)) == NULL
)
397 newsk
= dccp_create_openreq_child(sk
, req
, skb
);
401 sk_setup_caps(newsk
, dst
);
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
->opt
= ireq
->opt
;
410 newinet
->mc_index
= inet_iif(skb
);
411 newinet
->mc_ttl
= ip_hdr(skb
)->ttl
;
412 newinet
->inet_id
= jiffies
;
414 dccp_sync_mss(newsk
, dst_mtu(dst
));
416 if (__inet_inherit_port(sk
, newsk
) < 0) {
420 __inet_hash_nolisten(newsk
, NULL
);
425 NET_INC_STATS_BH(sock_net(sk
), LINUX_MIB_LISTENOVERFLOWS
);
429 NET_INC_STATS_BH(sock_net(sk
), LINUX_MIB_LISTENDROPS
);
433 EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock
);
435 static struct sock
*dccp_v4_hnd_req(struct sock
*sk
, struct sk_buff
*skb
)
437 const struct dccp_hdr
*dh
= dccp_hdr(skb
);
438 const struct iphdr
*iph
= ip_hdr(skb
);
440 struct request_sock
**prev
;
441 /* Find possible connection requests. */
442 struct request_sock
*req
= inet_csk_search_req(sk
, &prev
,
444 iph
->saddr
, iph
->daddr
);
446 return dccp_check_req(sk
, skb
, req
, prev
);
448 nsk
= inet_lookup_established(sock_net(sk
), &dccp_hashinfo
,
449 iph
->saddr
, dh
->dccph_sport
,
450 iph
->daddr
, dh
->dccph_dport
,
453 if (nsk
->sk_state
!= DCCP_TIME_WAIT
) {
457 inet_twsk_put(inet_twsk(nsk
));
464 static struct dst_entry
* dccp_v4_route_skb(struct net
*net
, struct sock
*sk
,
468 struct flowi fl
= { .oif
= skb_rtable(skb
)->rt_iif
,
469 .fl4_dst
= ip_hdr(skb
)->saddr
,
470 .fl4_src
= ip_hdr(skb
)->daddr
,
471 .fl4_tos
= RT_CONN_FLAGS(sk
),
472 .proto
= sk
->sk_protocol
,
473 .fl_ip_sport
= dccp_hdr(skb
)->dccph_dport
,
474 .fl_ip_dport
= dccp_hdr(skb
)->dccph_sport
477 security_skb_classify_flow(skb
, &fl
);
478 if (ip_route_output_flow(net
, &rt
, &fl
, sk
)) {
479 IP_INC_STATS_BH(net
, IPSTATS_MIB_OUTNOROUTES
);
486 static int dccp_v4_send_response(struct sock
*sk
, struct request_sock
*req
,
487 struct request_values
*rv_unused
)
491 struct dst_entry
*dst
;
493 dst
= inet_csk_route_req(sk
, req
);
497 skb
= dccp_make_response(sk
, dst
, req
);
499 const struct inet_request_sock
*ireq
= inet_rsk(req
);
500 struct dccp_hdr
*dh
= dccp_hdr(skb
);
502 dh
->dccph_checksum
= dccp_v4_csum_finish(skb
, ireq
->loc_addr
,
504 err
= ip_build_and_send_pkt(skb
, sk
, ireq
->loc_addr
,
507 err
= net_xmit_eval(err
);
515 static void dccp_v4_ctl_send_reset(struct sock
*sk
, struct sk_buff
*rxskb
)
518 const struct iphdr
*rxiph
;
520 struct dst_entry
*dst
;
521 struct net
*net
= dev_net(skb_dst(rxskb
)->dev
);
522 struct sock
*ctl_sk
= net
->dccp
.v4_ctl_sk
;
524 /* Never send a reset in response to a reset. */
525 if (dccp_hdr(rxskb
)->dccph_type
== DCCP_PKT_RESET
)
528 if (skb_rtable(rxskb
)->rt_type
!= RTN_LOCAL
)
531 dst
= dccp_v4_route_skb(net
, ctl_sk
, rxskb
);
535 skb
= dccp_ctl_make_reset(ctl_sk
, rxskb
);
539 rxiph
= ip_hdr(rxskb
);
540 dccp_hdr(skb
)->dccph_checksum
= dccp_v4_csum_finish(skb
, rxiph
->saddr
,
542 skb_dst_set(skb
, dst_clone(dst
));
544 bh_lock_sock(ctl_sk
);
545 err
= ip_build_and_send_pkt(skb
, ctl_sk
,
546 rxiph
->daddr
, rxiph
->saddr
, NULL
);
547 bh_unlock_sock(ctl_sk
);
549 if (net_xmit_eval(err
) == 0) {
550 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS
);
551 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS
);
557 static void dccp_v4_reqsk_destructor(struct request_sock
*req
)
559 dccp_feat_list_purge(&dccp_rsk(req
)->dreq_featneg
);
560 kfree(inet_rsk(req
)->opt
);
563 static struct request_sock_ops dccp_request_sock_ops __read_mostly
= {
565 .obj_size
= sizeof(struct dccp_request_sock
),
566 .rtx_syn_ack
= dccp_v4_send_response
,
567 .send_ack
= dccp_reqsk_send_ack
,
568 .destructor
= dccp_v4_reqsk_destructor
,
569 .send_reset
= dccp_v4_ctl_send_reset
,
572 int dccp_v4_conn_request(struct sock
*sk
, struct sk_buff
*skb
)
574 struct inet_request_sock
*ireq
;
575 struct request_sock
*req
;
576 struct dccp_request_sock
*dreq
;
577 const __be32 service
= dccp_hdr_request(skb
)->dccph_req_service
;
578 struct dccp_skb_cb
*dcb
= DCCP_SKB_CB(skb
);
580 /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
581 if (skb_rtable(skb
)->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
))
582 return 0; /* discard, don't send a reset here */
584 if (dccp_bad_service_code(sk
, service
)) {
585 dcb
->dccpd_reset_code
= DCCP_RESET_CODE_BAD_SERVICE_CODE
;
589 * TW buckets are converted to open requests without
590 * limitations, they conserve resources and peer is
591 * evidently real one.
593 dcb
->dccpd_reset_code
= DCCP_RESET_CODE_TOO_BUSY
;
594 if (inet_csk_reqsk_queue_is_full(sk
))
598 * Accept backlog is full. If we have already queued enough
599 * of warm entries in syn queue, drop request. It is better than
600 * clogging syn queue with openreqs with exponentially increasing
603 if (sk_acceptq_is_full(sk
) && inet_csk_reqsk_queue_young(sk
) > 1)
606 req
= inet_reqsk_alloc(&dccp_request_sock_ops
);
610 if (dccp_reqsk_init(req
, dccp_sk(sk
), skb
))
613 dreq
= dccp_rsk(req
);
614 if (dccp_parse_options(sk
, dreq
, skb
))
617 if (security_inet_conn_request(sk
, skb
, req
))
620 ireq
= inet_rsk(req
);
621 ireq
->loc_addr
= ip_hdr(skb
)->daddr
;
622 ireq
->rmt_addr
= ip_hdr(skb
)->saddr
;
625 * Step 3: Process LISTEN state
627 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
629 * In fact we defer setting S.GSR, S.SWL, S.SWH to
630 * dccp_create_openreq_child.
632 dreq
->dreq_isr
= dcb
->dccpd_seq
;
633 dreq
->dreq_iss
= dccp_v4_init_sequence(skb
);
634 dreq
->dreq_service
= service
;
636 if (dccp_v4_send_response(sk
, req
, NULL
))
639 inet_csk_reqsk_queue_hash_add(sk
, req
, DCCP_TIMEOUT_INIT
);
645 DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS
);
649 EXPORT_SYMBOL_GPL(dccp_v4_conn_request
);
651 int dccp_v4_do_rcv(struct sock
*sk
, struct sk_buff
*skb
)
653 struct dccp_hdr
*dh
= dccp_hdr(skb
);
655 if (sk
->sk_state
== DCCP_OPEN
) { /* Fast path */
656 if (dccp_rcv_established(sk
, skb
, dh
, skb
->len
))
662 * Step 3: Process LISTEN state
663 * If P.type == Request or P contains a valid Init Cookie option,
664 * (* Must scan the packet's options to check for Init
665 * Cookies. Only Init Cookies are processed here,
666 * however; other options are processed in Step 8. This
667 * scan need only be performed if the endpoint uses Init
669 * (* Generate a new socket and switch to that socket *)
670 * Set S := new socket for this port pair
672 * Choose S.ISS (initial seqno) or set from Init Cookies
673 * Initialize S.GAR := S.ISS
674 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
675 * Continue with S.state == RESPOND
676 * (* A Response packet will be generated in Step 11 *)
678 * Generate Reset(No Connection) unless P.type == Reset
679 * Drop packet and return
681 * NOTE: the check for the packet types is done in
682 * dccp_rcv_state_process
684 if (sk
->sk_state
== DCCP_LISTEN
) {
685 struct sock
*nsk
= dccp_v4_hnd_req(sk
, skb
);
691 if (dccp_child_process(sk
, nsk
, skb
))
697 if (dccp_rcv_state_process(sk
, skb
, dh
, skb
->len
))
702 dccp_v4_ctl_send_reset(sk
, skb
);
708 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv
);
711 * dccp_invalid_packet - check for malformed packets
712 * Implements RFC 4340, 8.5: Step 1: Check header basics
713 * Packets that fail these checks are ignored and do not receive Resets.
715 int dccp_invalid_packet(struct sk_buff
*skb
)
717 const struct dccp_hdr
*dh
;
720 if (skb
->pkt_type
!= PACKET_HOST
)
723 /* If the packet is shorter than 12 bytes, drop packet and return */
724 if (!pskb_may_pull(skb
, sizeof(struct dccp_hdr
))) {
725 DCCP_WARN("pskb_may_pull failed\n");
731 /* If P.type is not understood, drop packet and return */
732 if (dh
->dccph_type
>= DCCP_PKT_INVALID
) {
733 DCCP_WARN("invalid packet type\n");
738 * If P.Data Offset is too small for packet type, drop packet and return
740 if (dh
->dccph_doff
< dccp_hdr_len(skb
) / sizeof(u32
)) {
741 DCCP_WARN("P.Data Offset(%u) too small\n", dh
->dccph_doff
);
745 * If P.Data Offset is too too large for packet, drop packet and return
747 if (!pskb_may_pull(skb
, dh
->dccph_doff
* sizeof(u32
))) {
748 DCCP_WARN("P.Data Offset(%u) too large\n", dh
->dccph_doff
);
753 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
754 * has short sequence numbers), drop packet and return
756 if ((dh
->dccph_type
< DCCP_PKT_DATA
||
757 dh
->dccph_type
> DCCP_PKT_DATAACK
) && dh
->dccph_x
== 0) {
758 DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
759 dccp_packet_name(dh
->dccph_type
));
764 * If P.CsCov is too large for the packet size, drop packet and return.
765 * This must come _before_ checksumming (not as RFC 4340 suggests).
767 cscov
= dccp_csum_coverage(skb
);
768 if (cscov
> skb
->len
) {
769 DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
770 dh
->dccph_cscov
, skb
->len
);
774 /* If header checksum is incorrect, drop packet and return.
775 * (This step is completed in the AF-dependent functions.) */
776 skb
->csum
= skb_checksum(skb
, 0, cscov
, 0);
781 EXPORT_SYMBOL_GPL(dccp_invalid_packet
);
783 /* this is called when real data arrives */
784 static int dccp_v4_rcv(struct sk_buff
*skb
)
786 const struct dccp_hdr
*dh
;
787 const struct iphdr
*iph
;
791 /* Step 1: Check header basics */
793 if (dccp_invalid_packet(skb
))
797 /* Step 1: If header checksum is incorrect, drop packet and return */
798 if (dccp_v4_csum_finish(skb
, iph
->saddr
, iph
->daddr
)) {
799 DCCP_WARN("dropped packet with invalid checksum\n");
805 DCCP_SKB_CB(skb
)->dccpd_seq
= dccp_hdr_seq(dh
);
806 DCCP_SKB_CB(skb
)->dccpd_type
= dh
->dccph_type
;
808 dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
809 dccp_packet_name(dh
->dccph_type
),
810 &iph
->saddr
, ntohs(dh
->dccph_sport
),
811 &iph
->daddr
, ntohs(dh
->dccph_dport
),
812 (unsigned long long) DCCP_SKB_CB(skb
)->dccpd_seq
);
814 if (dccp_packet_without_ack(skb
)) {
815 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= DCCP_PKT_WITHOUT_ACK_SEQ
;
816 dccp_pr_debug_cat("\n");
818 DCCP_SKB_CB(skb
)->dccpd_ack_seq
= dccp_hdr_ack_seq(skb
);
819 dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
820 DCCP_SKB_CB(skb
)->dccpd_ack_seq
);
824 * Look up flow ID in table and get corresponding socket */
825 sk
= __inet_lookup_skb(&dccp_hashinfo
, skb
,
826 dh
->dccph_sport
, dh
->dccph_dport
);
832 dccp_pr_debug("failed to look up flow ID in table and "
833 "get corresponding socket\n");
839 * ... or S.state == TIMEWAIT,
840 * Generate Reset(No Connection) unless P.type == Reset
841 * Drop packet and return
843 if (sk
->sk_state
== DCCP_TIME_WAIT
) {
844 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
845 inet_twsk_put(inet_twsk(sk
));
850 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
851 * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
852 * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
854 min_cov
= dccp_sk(sk
)->dccps_pcrlen
;
855 if (dh
->dccph_cscov
&& (min_cov
== 0 || dh
->dccph_cscov
< min_cov
)) {
856 dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
857 dh
->dccph_cscov
, min_cov
);
858 /* FIXME: "Such packets SHOULD be reported using Data Dropped
859 * options (Section 11.7) with Drop Code 0, Protocol
861 goto discard_and_relse
;
864 if (!xfrm4_policy_check(sk
, XFRM_POLICY_IN
, skb
))
865 goto discard_and_relse
;
868 return sk_receive_skb(sk
, skb
, 1);
871 if (!xfrm4_policy_check(NULL
, XFRM_POLICY_IN
, skb
))
876 * Generate Reset(No Connection) unless P.type == Reset
877 * Drop packet and return
879 if (dh
->dccph_type
!= DCCP_PKT_RESET
) {
880 DCCP_SKB_CB(skb
)->dccpd_reset_code
=
881 DCCP_RESET_CODE_NO_CONNECTION
;
882 dccp_v4_ctl_send_reset(sk
, skb
);
894 static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops
= {
895 .queue_xmit
= ip_queue_xmit
,
896 .send_check
= dccp_v4_send_check
,
897 .rebuild_header
= inet_sk_rebuild_header
,
898 .conn_request
= dccp_v4_conn_request
,
899 .syn_recv_sock
= dccp_v4_request_recv_sock
,
900 .net_header_len
= sizeof(struct iphdr
),
901 .setsockopt
= ip_setsockopt
,
902 .getsockopt
= ip_getsockopt
,
903 .addr2sockaddr
= inet_csk_addr2sockaddr
,
904 .sockaddr_len
= sizeof(struct sockaddr_in
),
905 .bind_conflict
= inet_csk_bind_conflict
,
907 .compat_setsockopt
= compat_ip_setsockopt
,
908 .compat_getsockopt
= compat_ip_getsockopt
,
912 static int dccp_v4_init_sock(struct sock
*sk
)
914 static __u8 dccp_v4_ctl_sock_initialized
;
915 int err
= dccp_init_sock(sk
, dccp_v4_ctl_sock_initialized
);
918 if (unlikely(!dccp_v4_ctl_sock_initialized
))
919 dccp_v4_ctl_sock_initialized
= 1;
920 inet_csk(sk
)->icsk_af_ops
= &dccp_ipv4_af_ops
;
926 static struct timewait_sock_ops dccp_timewait_sock_ops
= {
927 .twsk_obj_size
= sizeof(struct inet_timewait_sock
),
930 static struct proto dccp_v4_prot
= {
932 .owner
= THIS_MODULE
,
934 .connect
= dccp_v4_connect
,
935 .disconnect
= dccp_disconnect
,
937 .init
= dccp_v4_init_sock
,
938 .setsockopt
= dccp_setsockopt
,
939 .getsockopt
= dccp_getsockopt
,
940 .sendmsg
= dccp_sendmsg
,
941 .recvmsg
= dccp_recvmsg
,
942 .backlog_rcv
= dccp_v4_do_rcv
,
944 .unhash
= inet_unhash
,
945 .accept
= inet_csk_accept
,
946 .get_port
= inet_csk_get_port
,
947 .shutdown
= dccp_shutdown
,
948 .destroy
= dccp_destroy_sock
,
949 .orphan_count
= &dccp_orphan_count
,
950 .max_header
= MAX_DCCP_HEADER
,
951 .obj_size
= sizeof(struct dccp_sock
),
952 .slab_flags
= SLAB_DESTROY_BY_RCU
,
953 .rsk_prot
= &dccp_request_sock_ops
,
954 .twsk_prot
= &dccp_timewait_sock_ops
,
955 .h
.hashinfo
= &dccp_hashinfo
,
957 .compat_setsockopt
= compat_dccp_setsockopt
,
958 .compat_getsockopt
= compat_dccp_getsockopt
,
962 static const struct net_protocol dccp_v4_protocol
= {
963 .handler
= dccp_v4_rcv
,
964 .err_handler
= dccp_v4_err
,
969 static const struct proto_ops inet_dccp_ops
= {
971 .owner
= THIS_MODULE
,
972 .release
= inet_release
,
974 .connect
= inet_stream_connect
,
975 .socketpair
= sock_no_socketpair
,
976 .accept
= inet_accept
,
977 .getname
= inet_getname
,
978 /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
981 /* FIXME: work on inet_listen to rename it to sock_common_listen */
982 .listen
= inet_dccp_listen
,
983 .shutdown
= inet_shutdown
,
984 .setsockopt
= sock_common_setsockopt
,
985 .getsockopt
= sock_common_getsockopt
,
986 .sendmsg
= inet_sendmsg
,
987 .recvmsg
= sock_common_recvmsg
,
988 .mmap
= sock_no_mmap
,
989 .sendpage
= sock_no_sendpage
,
991 .compat_setsockopt
= compat_sock_common_setsockopt
,
992 .compat_getsockopt
= compat_sock_common_getsockopt
,
996 static struct inet_protosw dccp_v4_protosw
= {
998 .protocol
= IPPROTO_DCCP
,
999 .prot
= &dccp_v4_prot
,
1000 .ops
= &inet_dccp_ops
,
1002 .flags
= INET_PROTOSW_ICSK
,
1005 static int __net_init
dccp_v4_init_net(struct net
*net
)
1007 if (dccp_hashinfo
.bhash
== NULL
)
1008 return -ESOCKTNOSUPPORT
;
1010 return inet_ctl_sock_create(&net
->dccp
.v4_ctl_sk
, PF_INET
,
1011 SOCK_DCCP
, IPPROTO_DCCP
, net
);
1014 static void __net_exit
dccp_v4_exit_net(struct net
*net
)
1016 inet_ctl_sock_destroy(net
->dccp
.v4_ctl_sk
);
1019 static struct pernet_operations dccp_v4_ops
= {
1020 .init
= dccp_v4_init_net
,
1021 .exit
= dccp_v4_exit_net
,
1024 static int __init
dccp_v4_init(void)
1026 int err
= proto_register(&dccp_v4_prot
, 1);
1031 err
= inet_add_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1033 goto out_proto_unregister
;
1035 inet_register_protosw(&dccp_v4_protosw
);
1037 err
= register_pernet_subsys(&dccp_v4_ops
);
1039 goto out_destroy_ctl_sock
;
1042 out_destroy_ctl_sock
:
1043 inet_unregister_protosw(&dccp_v4_protosw
);
1044 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1045 out_proto_unregister
:
1046 proto_unregister(&dccp_v4_prot
);
1050 static void __exit
dccp_v4_exit(void)
1052 unregister_pernet_subsys(&dccp_v4_ops
);
1053 inet_unregister_protosw(&dccp_v4_protosw
);
1054 inet_del_protocol(&dccp_v4_protocol
, IPPROTO_DCCP
);
1055 proto_unregister(&dccp_v4_prot
);
1058 module_init(dccp_v4_init
);
1059 module_exit(dccp_v4_exit
);
1062 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
1063 * values directly, Also cover the case where the protocol is not specified,
1064 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
1066 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET
, 33, 6);
1067 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET
, 0, 6);
1068 MODULE_LICENSE("GPL");
1069 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
1070 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");