v4.19.13 snapshot.
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
new file mode 100644
index 0000000..8e08cea
--- /dev/null
+++ b/net/dccp/ipv4.c
@@ -0,0 +1,1086 @@
+/*
+ * net/dccp/ipv4.c
+ *
+ * An implementation of the DCCP protocol
+ * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/dccp.h>
+#include <linux/icmp.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/random.h>
+
+#include <net/icmp.h>
+#include <net/inet_common.h>
+#include <net/inet_hashtables.h>
+#include <net/inet_sock.h>
+#include <net/protocol.h>
+#include <net/sock.h>
+#include <net/timewait_sock.h>
+#include <net/tcp_states.h>
+#include <net/xfrm.h>
+#include <net/secure_seq.h>
+
+#include "ackvec.h"
+#include "ccid.h"
+#include "dccp.h"
+#include "feat.h"
+
+/*
+ * The per-net dccp.v4_ctl_sk socket is used for responding to
+ * the Out-of-the-blue (OOTB) packets. A control sock will be created
+ * for this socket at the initialization time.
+ */
+
+int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+{
+ const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
+ struct inet_sock *inet = inet_sk(sk);
+ struct dccp_sock *dp = dccp_sk(sk);
+ __be16 orig_sport, orig_dport;
+ __be32 daddr, nexthop;
+ struct flowi4 *fl4;
+ struct rtable *rt;
+ int err;
+ struct ip_options_rcu *inet_opt;
+
+ dp->dccps_role = DCCP_ROLE_CLIENT;
+
+ if (addr_len < sizeof(struct sockaddr_in))
+ return -EINVAL;
+
+ if (usin->sin_family != AF_INET)
+ return -EAFNOSUPPORT;
+
+ nexthop = daddr = usin->sin_addr.s_addr;
+
+ inet_opt = rcu_dereference_protected(inet->inet_opt,
+ lockdep_sock_is_held(sk));
+ if (inet_opt != NULL && inet_opt->opt.srr) {
+ if (daddr == 0)
+ return -EINVAL;
+ nexthop = inet_opt->opt.faddr;
+ }
+
+ orig_sport = inet->inet_sport;
+ orig_dport = usin->sin_port;
+ fl4 = &inet->cork.fl.u.ip4;
+ rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
+ RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
+ IPPROTO_DCCP,
+ orig_sport, orig_dport, sk);
+ if (IS_ERR(rt))
+ return PTR_ERR(rt);
+
+ if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
+ ip_rt_put(rt);
+ return -ENETUNREACH;
+ }
+
+ if (inet_opt == NULL || !inet_opt->opt.srr)
+ daddr = fl4->daddr;
+
+ if (inet->inet_saddr == 0)
+ inet->inet_saddr = fl4->saddr;
+ sk_rcv_saddr_set(sk, inet->inet_saddr);
+ inet->inet_dport = usin->sin_port;
+ sk_daddr_set(sk, daddr);
+
+ inet_csk(sk)->icsk_ext_hdr_len = 0;
+ if (inet_opt)
+ inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
+ /*
+ * Socket identity is still unknown (sport may be zero).
+ * However we set state to DCCP_REQUESTING and not releasing socket
+ * lock select source port, enter ourselves into the hash tables and
+ * complete initialization after this.
+ */
+ dccp_set_state(sk, DCCP_REQUESTING);
+ err = inet_hash_connect(&dccp_death_row, sk);
+ if (err != 0)
+ goto failure;
+
+ rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
+ inet->inet_sport, inet->inet_dport, sk);
+ if (IS_ERR(rt)) {
+ err = PTR_ERR(rt);
+ rt = NULL;
+ goto failure;
+ }
+ /* OK, now commit destination to socket. */
+ sk_setup_caps(sk, &rt->dst);
+
+ dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
+ inet->inet_daddr,
+ inet->inet_sport,
+ inet->inet_dport);
+ inet->inet_id = dp->dccps_iss ^ jiffies;
+
+ err = dccp_connect(sk);
+ rt = NULL;
+ if (err != 0)
+ goto failure;
+out:
+ return err;
+failure:
+ /*
+ * This unhashes the socket and releases the local port, if necessary.
+ */
+ dccp_set_state(sk, DCCP_CLOSED);
+ ip_rt_put(rt);
+ sk->sk_route_caps = 0;
+ inet->inet_dport = 0;
+ goto out;
+}
+EXPORT_SYMBOL_GPL(dccp_v4_connect);
+
+/*
+ * This routine does path mtu discovery as defined in RFC1191.
+ */
+static inline void dccp_do_pmtu_discovery(struct sock *sk,
+ const struct iphdr *iph,
+ u32 mtu)
+{
+ struct dst_entry *dst;
+ const struct inet_sock *inet = inet_sk(sk);
+ const struct dccp_sock *dp = dccp_sk(sk);
+
+ /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
+ * send out by Linux are always < 576bytes so they should go through
+ * unfragmented).
+ */
+ if (sk->sk_state == DCCP_LISTEN)
+ return;
+
+ dst = inet_csk_update_pmtu(sk, mtu);
+ if (!dst)
+ return;
+
+ /* Something is about to be wrong... Remember soft error
+ * for the case, if this connection will not able to recover.
+ */
+ if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
+ sk->sk_err_soft = EMSGSIZE;
+
+ mtu = dst_mtu(dst);
+
+ if (inet->pmtudisc != IP_PMTUDISC_DONT &&
+ ip_sk_accept_pmtu(sk) &&
+ inet_csk(sk)->icsk_pmtu_cookie > mtu) {
+ dccp_sync_mss(sk, mtu);
+
+ /*
+ * From RFC 4340, sec. 14.1:
+ *
+ * DCCP-Sync packets are the best choice for upward
+ * probing, since DCCP-Sync probes do not risk application
+ * data loss.
+ */
+ dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
+ } /* else let the usual retransmit timer handle it */
+}
+
+static void dccp_do_redirect(struct sk_buff *skb, struct sock *sk)
+{
+ struct dst_entry *dst = __sk_dst_check(sk, 0);
+
+ if (dst)
+ dst->ops->redirect(dst, sk, skb);
+}
+
+void dccp_req_err(struct sock *sk, u64 seq)
+ {
+ struct request_sock *req = inet_reqsk(sk);
+ struct net *net = sock_net(sk);
+
+ /*
+ * ICMPs are not backlogged, hence we cannot get an established
+ * socket here.
+ */
+ if (!between48(seq, dccp_rsk(req)->dreq_iss, dccp_rsk(req)->dreq_gss)) {
+ __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
+ } else {
+ /*
+ * Still in RESPOND, just remove it silently.
+ * There is no good way to pass the error to the newly
+ * created socket, and POSIX does not want network
+ * errors returned from accept().
+ */
+ inet_csk_reqsk_queue_drop(req->rsk_listener, req);
+ }
+ reqsk_put(req);
+}
+EXPORT_SYMBOL(dccp_req_err);
+
+/*
+ * This routine is called by the ICMP module when it gets some sort of error
+ * condition. If err < 0 then the socket should be closed and the error
+ * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
+ * After adjustment header points to the first 8 bytes of the tcp header. We
+ * need to find the appropriate port.
+ *
+ * The locking strategy used here is very "optimistic". When someone else
+ * accesses the socket the ICMP is just dropped and for some paths there is no
+ * check at all. A more general error queue to queue errors for later handling
+ * is probably better.
+ */
+static void dccp_v4_err(struct sk_buff *skb, u32 info)
+{
+ const struct iphdr *iph = (struct iphdr *)skb->data;
+ const u8 offset = iph->ihl << 2;
+ const struct dccp_hdr *dh;
+ struct dccp_sock *dp;
+ struct inet_sock *inet;
+ const int type = icmp_hdr(skb)->type;
+ const int code = icmp_hdr(skb)->code;
+ struct sock *sk;
+ __u64 seq;
+ int err;
+ struct net *net = dev_net(skb->dev);
+
+ /* Only need dccph_dport & dccph_sport which are the first
+ * 4 bytes in dccp header.
+ * Our caller (icmp_socket_deliver()) already pulled 8 bytes for us.
+ */
+ BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
+ BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
+ dh = (struct dccp_hdr *)(skb->data + offset);
+
+ sk = __inet_lookup_established(net, &dccp_hashinfo,
+ iph->daddr, dh->dccph_dport,
+ iph->saddr, ntohs(dh->dccph_sport),
+ inet_iif(skb), 0);
+ if (!sk) {
+ __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
+ return;
+ }
+
+ if (sk->sk_state == DCCP_TIME_WAIT) {
+ inet_twsk_put(inet_twsk(sk));
+ return;
+ }
+ seq = dccp_hdr_seq(dh);
+ if (sk->sk_state == DCCP_NEW_SYN_RECV)
+ return dccp_req_err(sk, seq);
+
+ bh_lock_sock(sk);
+ /* If too many ICMPs get dropped on busy
+ * servers this needs to be solved differently.
+ */
+ if (sock_owned_by_user(sk))
+ __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
+
+ if (sk->sk_state == DCCP_CLOSED)
+ goto out;
+
+ dp = dccp_sk(sk);
+ if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
+ !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
+ __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
+ goto out;
+ }
+
+ switch (type) {
+ case ICMP_REDIRECT:
+ if (!sock_owned_by_user(sk))
+ dccp_do_redirect(skb, sk);
+ goto out;
+ case ICMP_SOURCE_QUENCH:
+ /* Just silently ignore these. */
+ goto out;
+ case ICMP_PARAMETERPROB:
+ err = EPROTO;
+ break;
+ case ICMP_DEST_UNREACH:
+ if (code > NR_ICMP_UNREACH)
+ goto out;
+
+ if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
+ if (!sock_owned_by_user(sk))
+ dccp_do_pmtu_discovery(sk, iph, info);
+ goto out;
+ }
+
+ err = icmp_err_convert[code].errno;
+ break;
+ case ICMP_TIME_EXCEEDED:
+ err = EHOSTUNREACH;
+ break;
+ default:
+ goto out;
+ }
+
+ switch (sk->sk_state) {
+ case DCCP_REQUESTING:
+ case DCCP_RESPOND:
+ if (!sock_owned_by_user(sk)) {
+ __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
+ sk->sk_err = err;
+
+ sk->sk_error_report(sk);
+
+ dccp_done(sk);
+ } else
+ sk->sk_err_soft = err;
+ goto out;
+ }
+
+ /* If we've already connected we will keep trying
+ * until we time out, or the user gives up.
+ *
+ * rfc1122 4.2.3.9 allows to consider as hard errors
+ * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
+ * but it is obsoleted by pmtu discovery).
+ *
+ * Note, that in modern internet, where routing is unreliable
+ * and in each dark corner broken firewalls sit, sending random
+ * errors ordered by their masters even this two messages finally lose
+ * their original sense (even Linux sends invalid PORT_UNREACHs)
+ *
+ * Now we are in compliance with RFCs.
+ * --ANK (980905)
+ */
+
+ inet = inet_sk(sk);
+ if (!sock_owned_by_user(sk) && inet->recverr) {
+ sk->sk_err = err;
+ sk->sk_error_report(sk);
+ } else /* Only an error on timeout */
+ sk->sk_err_soft = err;
+out:
+ bh_unlock_sock(sk);
+ sock_put(sk);
+}
+
+static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
+ __be32 src, __be32 dst)
+{
+ return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
+}
+
+void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb)
+{
+ const struct inet_sock *inet = inet_sk(sk);
+ struct dccp_hdr *dh = dccp_hdr(skb);
+
+ dccp_csum_outgoing(skb);
+ dh->dccph_checksum = dccp_v4_csum_finish(skb,
+ inet->inet_saddr,
+ inet->inet_daddr);
+}
+EXPORT_SYMBOL_GPL(dccp_v4_send_check);
+
+static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
+{
+ return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
+ ip_hdr(skb)->saddr,
+ dccp_hdr(skb)->dccph_dport,
+ dccp_hdr(skb)->dccph_sport);
+}
+
+/*
+ * The three way handshake has completed - we got a valid ACK or DATAACK -
+ * now create the new socket.
+ *
+ * This is the equivalent of TCP's tcp_v4_syn_recv_sock
+ */
+struct sock *dccp_v4_request_recv_sock(const struct sock *sk,
+ struct sk_buff *skb,
+ struct request_sock *req,
+ struct dst_entry *dst,
+ struct request_sock *req_unhash,
+ bool *own_req)
+{
+ struct inet_request_sock *ireq;
+ struct inet_sock *newinet;
+ struct sock *newsk;
+
+ if (sk_acceptq_is_full(sk))
+ goto exit_overflow;
+
+ newsk = dccp_create_openreq_child(sk, req, skb);
+ if (newsk == NULL)
+ goto exit_nonewsk;
+
+ newinet = inet_sk(newsk);
+ ireq = inet_rsk(req);
+ sk_daddr_set(newsk, ireq->ir_rmt_addr);
+ sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
+ newinet->inet_saddr = ireq->ir_loc_addr;
+ RCU_INIT_POINTER(newinet->inet_opt, rcu_dereference(ireq->ireq_opt));
+ newinet->mc_index = inet_iif(skb);
+ newinet->mc_ttl = ip_hdr(skb)->ttl;
+ newinet->inet_id = jiffies;
+
+ if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
+ goto put_and_exit;
+
+ sk_setup_caps(newsk, dst);
+
+ dccp_sync_mss(newsk, dst_mtu(dst));
+
+ if (__inet_inherit_port(sk, newsk) < 0)
+ goto put_and_exit;
+ *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
+ if (*own_req)
+ ireq->ireq_opt = NULL;
+ else
+ newinet->inet_opt = NULL;
+ return newsk;
+
+exit_overflow:
+ __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
+exit_nonewsk:
+ dst_release(dst);
+exit:
+ __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
+ return NULL;
+put_and_exit:
+ newinet->inet_opt = NULL;
+ inet_csk_prepare_forced_close(newsk);
+ dccp_done(newsk);
+ goto exit;
+}
+EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
+
+static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
+ struct sk_buff *skb)
+{
+ struct rtable *rt;
+ const struct iphdr *iph = ip_hdr(skb);
+ struct flowi4 fl4 = {
+ .flowi4_oif = inet_iif(skb),
+ .daddr = iph->saddr,
+ .saddr = iph->daddr,
+ .flowi4_tos = RT_CONN_FLAGS(sk),
+ .flowi4_proto = sk->sk_protocol,
+ .fl4_sport = dccp_hdr(skb)->dccph_dport,
+ .fl4_dport = dccp_hdr(skb)->dccph_sport,
+ };
+
+ security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
+ rt = ip_route_output_flow(net, &fl4, sk);
+ if (IS_ERR(rt)) {
+ IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
+ return NULL;
+ }
+
+ return &rt->dst;
+}
+
+static int dccp_v4_send_response(const struct sock *sk, struct request_sock *req)
+{
+ int err = -1;
+ struct sk_buff *skb;
+ struct dst_entry *dst;
+ struct flowi4 fl4;
+
+ dst = inet_csk_route_req(sk, &fl4, req);
+ if (dst == NULL)
+ goto out;
+
+ skb = dccp_make_response(sk, dst, req);
+ if (skb != NULL) {
+ const struct inet_request_sock *ireq = inet_rsk(req);
+ struct dccp_hdr *dh = dccp_hdr(skb);
+
+ dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->ir_loc_addr,
+ ireq->ir_rmt_addr);
+ rcu_read_lock();
+ err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
+ ireq->ir_rmt_addr,
+ rcu_dereference(ireq->ireq_opt));
+ rcu_read_unlock();
+ err = net_xmit_eval(err);
+ }
+
+out:
+ dst_release(dst);
+ return err;
+}
+
+static void dccp_v4_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
+{
+ int err;
+ const struct iphdr *rxiph;
+ struct sk_buff *skb;
+ struct dst_entry *dst;
+ struct net *net = dev_net(skb_dst(rxskb)->dev);
+ struct sock *ctl_sk = net->dccp.v4_ctl_sk;
+
+ /* Never send a reset in response to a reset. */
+ if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
+ return;
+
+ if (skb_rtable(rxskb)->rt_type != RTN_LOCAL)
+ return;
+
+ dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
+ if (dst == NULL)
+ return;
+
+ skb = dccp_ctl_make_reset(ctl_sk, rxskb);
+ if (skb == NULL)
+ goto out;
+
+ rxiph = ip_hdr(rxskb);
+ dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
+ rxiph->daddr);
+ skb_dst_set(skb, dst_clone(dst));
+
+ local_bh_disable();
+ bh_lock_sock(ctl_sk);
+ err = ip_build_and_send_pkt(skb, ctl_sk,
+ rxiph->daddr, rxiph->saddr, NULL);
+ bh_unlock_sock(ctl_sk);
+
+ if (net_xmit_eval(err) == 0) {
+ __DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+ __DCCP_INC_STATS(DCCP_MIB_OUTRSTS);
+ }
+ local_bh_enable();
+out:
+ dst_release(dst);
+}
+
+static void dccp_v4_reqsk_destructor(struct request_sock *req)
+{
+ dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
+ kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
+}
+
+void dccp_syn_ack_timeout(const struct request_sock *req)
+{
+}
+EXPORT_SYMBOL(dccp_syn_ack_timeout);
+
+static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
+ .family = PF_INET,
+ .obj_size = sizeof(struct dccp_request_sock),
+ .rtx_syn_ack = dccp_v4_send_response,
+ .send_ack = dccp_reqsk_send_ack,
+ .destructor = dccp_v4_reqsk_destructor,
+ .send_reset = dccp_v4_ctl_send_reset,
+ .syn_ack_timeout = dccp_syn_ack_timeout,
+};
+
+int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
+{
+ struct inet_request_sock *ireq;
+ struct request_sock *req;
+ struct dccp_request_sock *dreq;
+ const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
+ struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+
+ /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
+ if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
+ return 0; /* discard, don't send a reset here */
+
+ if (dccp_bad_service_code(sk, service)) {
+ dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
+ goto drop;
+ }
+ /*
+ * TW buckets are converted to open requests without
+ * limitations, they conserve resources and peer is
+ * evidently real one.
+ */
+ dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
+ if (inet_csk_reqsk_queue_is_full(sk))
+ goto drop;
+
+ if (sk_acceptq_is_full(sk))
+ goto drop;
+
+ req = inet_reqsk_alloc(&dccp_request_sock_ops, sk, true);
+ if (req == NULL)
+ goto drop;
+
+ if (dccp_reqsk_init(req, dccp_sk(sk), skb))
+ goto drop_and_free;
+
+ dreq = dccp_rsk(req);
+ if (dccp_parse_options(sk, dreq, skb))
+ goto drop_and_free;
+
+ if (security_inet_conn_request(sk, skb, req))
+ goto drop_and_free;
+
+ ireq = inet_rsk(req);
+ sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
+ sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
+ ireq->ir_mark = inet_request_mark(sk, skb);
+ ireq->ireq_family = AF_INET;
+ ireq->ir_iif = sk->sk_bound_dev_if;
+
+ /*
+ * Step 3: Process LISTEN state
+ *
+ * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
+ *
+ * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
+ */
+ dreq->dreq_isr = dcb->dccpd_seq;
+ dreq->dreq_gsr = dreq->dreq_isr;
+ dreq->dreq_iss = dccp_v4_init_sequence(skb);
+ dreq->dreq_gss = dreq->dreq_iss;
+ dreq->dreq_service = service;
+
+ if (dccp_v4_send_response(sk, req))
+ goto drop_and_free;
+
+ inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
+ reqsk_put(req);
+ return 0;
+
+drop_and_free:
+ reqsk_free(req);
+drop:
+ __DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
+ return -1;
+}
+EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
+
+int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
+{
+ struct dccp_hdr *dh = dccp_hdr(skb);
+
+ if (sk->sk_state == DCCP_OPEN) { /* Fast path */
+ if (dccp_rcv_established(sk, skb, dh, skb->len))
+ goto reset;
+ return 0;
+ }
+
+ /*
+ * Step 3: Process LISTEN state
+ * If P.type == Request or P contains a valid Init Cookie option,
+ * (* Must scan the packet's options to check for Init
+ * Cookies. Only Init Cookies are processed here,
+ * however; other options are processed in Step 8. This
+ * scan need only be performed if the endpoint uses Init
+ * Cookies *)
+ * (* Generate a new socket and switch to that socket *)
+ * Set S := new socket for this port pair
+ * S.state = RESPOND
+ * Choose S.ISS (initial seqno) or set from Init Cookies
+ * Initialize S.GAR := S.ISS
+ * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
+ * Continue with S.state == RESPOND
+ * (* A Response packet will be generated in Step 11 *)
+ * Otherwise,
+ * Generate Reset(No Connection) unless P.type == Reset
+ * Drop packet and return
+ *
+ * NOTE: the check for the packet types is done in
+ * dccp_rcv_state_process
+ */
+
+ if (dccp_rcv_state_process(sk, skb, dh, skb->len))
+ goto reset;
+ return 0;
+
+reset:
+ dccp_v4_ctl_send_reset(sk, skb);
+ kfree_skb(skb);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
+
+/**
+ * dccp_invalid_packet - check for malformed packets
+ * Implements RFC 4340, 8.5: Step 1: Check header basics
+ * Packets that fail these checks are ignored and do not receive Resets.
+ */
+int dccp_invalid_packet(struct sk_buff *skb)
+{
+ const struct dccp_hdr *dh;
+ unsigned int cscov;
+ u8 dccph_doff;
+
+ if (skb->pkt_type != PACKET_HOST)
+ return 1;
+
+ /* If the packet is shorter than 12 bytes, drop packet and return */
+ if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
+ DCCP_WARN("pskb_may_pull failed\n");
+ return 1;
+ }
+
+ dh = dccp_hdr(skb);
+
+ /* If P.type is not understood, drop packet and return */
+ if (dh->dccph_type >= DCCP_PKT_INVALID) {
+ DCCP_WARN("invalid packet type\n");
+ return 1;
+ }
+
+ /*
+ * If P.Data Offset is too small for packet type, drop packet and return
+ */
+ dccph_doff = dh->dccph_doff;
+ if (dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
+ DCCP_WARN("P.Data Offset(%u) too small\n", dccph_doff);
+ return 1;
+ }
+ /*
+ * If P.Data Offset is too too large for packet, drop packet and return
+ */
+ if (!pskb_may_pull(skb, dccph_doff * sizeof(u32))) {
+ DCCP_WARN("P.Data Offset(%u) too large\n", dccph_doff);
+ return 1;
+ }
+ dh = dccp_hdr(skb);
+ /*
+ * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
+ * has short sequence numbers), drop packet and return
+ */
+ if ((dh->dccph_type < DCCP_PKT_DATA ||
+ dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0) {
+ DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
+ dccp_packet_name(dh->dccph_type));
+ return 1;
+ }
+
+ /*
+ * If P.CsCov is too large for the packet size, drop packet and return.
+ * This must come _before_ checksumming (not as RFC 4340 suggests).
+ */
+ cscov = dccp_csum_coverage(skb);
+ if (cscov > skb->len) {
+ DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
+ dh->dccph_cscov, skb->len);
+ return 1;
+ }
+
+ /* If header checksum is incorrect, drop packet and return.
+ * (This step is completed in the AF-dependent functions.) */
+ skb->csum = skb_checksum(skb, 0, cscov, 0);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dccp_invalid_packet);
+
+/* this is called when real data arrives */
+static int dccp_v4_rcv(struct sk_buff *skb)
+{
+ const struct dccp_hdr *dh;
+ const struct iphdr *iph;
+ bool refcounted;
+ struct sock *sk;
+ int min_cov;
+
+ /* Step 1: Check header basics */
+
+ if (dccp_invalid_packet(skb))
+ goto discard_it;
+
+ iph = ip_hdr(skb);
+ /* Step 1: If header checksum is incorrect, drop packet and return */
+ if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
+ DCCP_WARN("dropped packet with invalid checksum\n");
+ goto discard_it;
+ }
+
+ dh = dccp_hdr(skb);
+
+ DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
+ DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
+
+ dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu",
+ dccp_packet_name(dh->dccph_type),
+ &iph->saddr, ntohs(dh->dccph_sport),
+ &iph->daddr, ntohs(dh->dccph_dport),
+ (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
+
+ if (dccp_packet_without_ack(skb)) {
+ DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
+ dccp_pr_debug_cat("\n");
+ } else {
+ DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
+ dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
+ DCCP_SKB_CB(skb)->dccpd_ack_seq);
+ }
+
+lookup:
+ sk = __inet_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
+ dh->dccph_sport, dh->dccph_dport, 0, &refcounted);
+ if (!sk) {
+ dccp_pr_debug("failed to look up flow ID in table and "
+ "get corresponding socket\n");
+ goto no_dccp_socket;
+ }
+
+ /*
+ * Step 2:
+ * ... or S.state == TIMEWAIT,
+ * Generate Reset(No Connection) unless P.type == Reset
+ * Drop packet and return
+ */
+ if (sk->sk_state == DCCP_TIME_WAIT) {
+ dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
+ inet_twsk_put(inet_twsk(sk));
+ goto no_dccp_socket;
+ }
+
+ if (sk->sk_state == DCCP_NEW_SYN_RECV) {
+ struct request_sock *req = inet_reqsk(sk);
+ struct sock *nsk;
+
+ sk = req->rsk_listener;
+ if (unlikely(sk->sk_state != DCCP_LISTEN)) {
+ inet_csk_reqsk_queue_drop_and_put(sk, req);
+ goto lookup;
+ }
+ sock_hold(sk);
+ refcounted = true;
+ nsk = dccp_check_req(sk, skb, req);
+ if (!nsk) {
+ reqsk_put(req);
+ goto discard_and_relse;
+ }
+ if (nsk == sk) {
+ reqsk_put(req);
+ } else if (dccp_child_process(sk, nsk, skb)) {
+ dccp_v4_ctl_send_reset(sk, skb);
+ goto discard_and_relse;
+ } else {
+ sock_put(sk);
+ return 0;
+ }
+ }
+ /*
+ * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
+ * o if MinCsCov = 0, only packets with CsCov = 0 are accepted
+ * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
+ */
+ min_cov = dccp_sk(sk)->dccps_pcrlen;
+ if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
+ dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
+ dh->dccph_cscov, min_cov);
+ /* FIXME: "Such packets SHOULD be reported using Data Dropped
+ * options (Section 11.7) with Drop Code 0, Protocol
+ * Constraints." */
+ goto discard_and_relse;
+ }
+
+ if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
+ goto discard_and_relse;
+ nf_reset(skb);
+
+ return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, refcounted);
+
+no_dccp_socket:
+ if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
+ goto discard_it;
+ /*
+ * Step 2:
+ * If no socket ...
+ * Generate Reset(No Connection) unless P.type == Reset
+ * Drop packet and return
+ */
+ if (dh->dccph_type != DCCP_PKT_RESET) {
+ DCCP_SKB_CB(skb)->dccpd_reset_code =
+ DCCP_RESET_CODE_NO_CONNECTION;
+ dccp_v4_ctl_send_reset(sk, skb);
+ }
+
+discard_it:
+ kfree_skb(skb);
+ return 0;
+
+discard_and_relse:
+ if (refcounted)
+ sock_put(sk);
+ goto discard_it;
+}
+
+static const struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
+ .queue_xmit = ip_queue_xmit,
+ .send_check = dccp_v4_send_check,
+ .rebuild_header = inet_sk_rebuild_header,
+ .conn_request = dccp_v4_conn_request,
+ .syn_recv_sock = dccp_v4_request_recv_sock,
+ .net_header_len = sizeof(struct iphdr),
+ .setsockopt = ip_setsockopt,
+ .getsockopt = ip_getsockopt,
+ .addr2sockaddr = inet_csk_addr2sockaddr,
+ .sockaddr_len = sizeof(struct sockaddr_in),
+#ifdef CONFIG_COMPAT
+ .compat_setsockopt = compat_ip_setsockopt,
+ .compat_getsockopt = compat_ip_getsockopt,
+#endif
+};
+
+static int dccp_v4_init_sock(struct sock *sk)
+{
+ static __u8 dccp_v4_ctl_sock_initialized;
+ int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
+
+ if (err == 0) {
+ if (unlikely(!dccp_v4_ctl_sock_initialized))
+ dccp_v4_ctl_sock_initialized = 1;
+ inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
+ }
+
+ return err;
+}
+
+static struct timewait_sock_ops dccp_timewait_sock_ops = {
+ .twsk_obj_size = sizeof(struct inet_timewait_sock),
+};
+
+static struct proto dccp_v4_prot = {
+ .name = "DCCP",
+ .owner = THIS_MODULE,
+ .close = dccp_close,
+ .connect = dccp_v4_connect,
+ .disconnect = dccp_disconnect,
+ .ioctl = dccp_ioctl,
+ .init = dccp_v4_init_sock,
+ .setsockopt = dccp_setsockopt,
+ .getsockopt = dccp_getsockopt,
+ .sendmsg = dccp_sendmsg,
+ .recvmsg = dccp_recvmsg,
+ .backlog_rcv = dccp_v4_do_rcv,
+ .hash = inet_hash,
+ .unhash = inet_unhash,
+ .accept = inet_csk_accept,
+ .get_port = inet_csk_get_port,
+ .shutdown = dccp_shutdown,
+ .destroy = dccp_destroy_sock,
+ .orphan_count = &dccp_orphan_count,
+ .max_header = MAX_DCCP_HEADER,
+ .obj_size = sizeof(struct dccp_sock),
+ .slab_flags = SLAB_TYPESAFE_BY_RCU,
+ .rsk_prot = &dccp_request_sock_ops,
+ .twsk_prot = &dccp_timewait_sock_ops,
+ .h.hashinfo = &dccp_hashinfo,
+#ifdef CONFIG_COMPAT
+ .compat_setsockopt = compat_dccp_setsockopt,
+ .compat_getsockopt = compat_dccp_getsockopt,
+#endif
+};
+
+static const struct net_protocol dccp_v4_protocol = {
+ .handler = dccp_v4_rcv,
+ .err_handler = dccp_v4_err,
+ .no_policy = 1,
+ .netns_ok = 1,
+ .icmp_strict_tag_validation = 1,
+};
+
+static const struct proto_ops inet_dccp_ops = {
+ .family = PF_INET,
+ .owner = THIS_MODULE,
+ .release = inet_release,
+ .bind = inet_bind,
+ .connect = inet_stream_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = inet_accept,
+ .getname = inet_getname,
+ /* FIXME: work on tcp_poll to rename it to inet_csk_poll */
+ .poll = dccp_poll,
+ .ioctl = inet_ioctl,
+ /* FIXME: work on inet_listen to rename it to sock_common_listen */
+ .listen = inet_dccp_listen,
+ .shutdown = inet_shutdown,
+ .setsockopt = sock_common_setsockopt,
+ .getsockopt = sock_common_getsockopt,
+ .sendmsg = inet_sendmsg,
+ .recvmsg = sock_common_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = sock_no_sendpage,
+#ifdef CONFIG_COMPAT
+ .compat_setsockopt = compat_sock_common_setsockopt,
+ .compat_getsockopt = compat_sock_common_getsockopt,
+#endif
+};
+
+static struct inet_protosw dccp_v4_protosw = {
+ .type = SOCK_DCCP,
+ .protocol = IPPROTO_DCCP,
+ .prot = &dccp_v4_prot,
+ .ops = &inet_dccp_ops,
+ .flags = INET_PROTOSW_ICSK,
+};
+
+static int __net_init dccp_v4_init_net(struct net *net)
+{
+ if (dccp_hashinfo.bhash == NULL)
+ return -ESOCKTNOSUPPORT;
+
+ return inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
+ SOCK_DCCP, IPPROTO_DCCP, net);
+}
+
+static void __net_exit dccp_v4_exit_net(struct net *net)
+{
+ inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
+}
+
+static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list)
+{
+ inet_twsk_purge(&dccp_hashinfo, AF_INET);
+}
+
+static struct pernet_operations dccp_v4_ops = {
+ .init = dccp_v4_init_net,
+ .exit = dccp_v4_exit_net,
+ .exit_batch = dccp_v4_exit_batch,
+};
+
+static int __init dccp_v4_init(void)
+{
+ int err = proto_register(&dccp_v4_prot, 1);
+
+ if (err)
+ goto out;
+
+ inet_register_protosw(&dccp_v4_protosw);
+
+ err = register_pernet_subsys(&dccp_v4_ops);
+ if (err)
+ goto out_destroy_ctl_sock;
+
+ err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
+ if (err)
+ goto out_proto_unregister;
+
+out:
+ return err;
+out_proto_unregister:
+ unregister_pernet_subsys(&dccp_v4_ops);
+out_destroy_ctl_sock:
+ inet_unregister_protosw(&dccp_v4_protosw);
+ proto_unregister(&dccp_v4_prot);
+ goto out;
+}
+
+static void __exit dccp_v4_exit(void)
+{
+ inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
+ unregister_pernet_subsys(&dccp_v4_ops);
+ inet_unregister_protosw(&dccp_v4_protosw);
+ proto_unregister(&dccp_v4_prot);
+}
+
+module_init(dccp_v4_init);
+module_exit(dccp_v4_exit);
+
+/*
+ * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
+ * values directly, Also cover the case where the protocol is not specified,
+ * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
+ */
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
+MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");