// SPDX-License-Identifier: GPL-2.0-or-later /* * net/dccp/ipv4.c * * An implementation of the DCCP protocol * Arnaldo Carvalho de Melo */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "ackvec.h" #include "ccid.h" #include "dccp.h" #include "feat.h" struct dccp_v4_pernet { struct sock *v4_ctl_sk; }; static unsigned int dccp_v4_pernet_id __read_mostly; /* * The per-net 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, 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) { err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET); if (err) { ip_rt_put(rt); return err; } } else { 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); atomic_set(&inet->inet_id, get_random_u16()); 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); inet_bhash2_reset_saddr(sk); 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)) WRITE_ONCE(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 int 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; 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); if (!pskb_may_pull(skb, offset + sizeof(*dh))) return -EINVAL; dh = (struct dccp_hdr *)(skb->data + offset); if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh))) return -EINVAL; iph = (struct iphdr *)skb->data; 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 -ENOENT; } if (sk->sk_state == DCCP_TIME_WAIT) { inet_twsk_put(inet_twsk(sk)); return 0; } seq = dccp_hdr_seq(dh); if (sk->sk_state == DCCP_NEW_SYN_RECV) { dccp_req_err(sk, seq); return 0; } 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_error_report(sk); dccp_done(sk); } else { WRITE_ONCE(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) */ if (!sock_owned_by_user(sk) && inet_test_bit(RECVERR, sk)) { sk->sk_err = err; sk_error_report(sk); } else { /* Only an error on timeout */ WRITE_ONCE(sk->sk_err_soft, err); } out: bh_unlock_sock(sk); sock_put(sk); return 0; } 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; atomic_set(&newinet->inet_id, get_random_u16()); 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), NULL); 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 = ip_sock_rt_tos(sk), .flowi4_scope = ip_sock_rt_scope(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_common(&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), READ_ONCE(inet_sk(sk)->tos)); 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, enum sk_rst_reason reason) { int err; const struct iphdr *rxiph; struct sk_buff *skb; struct dst_entry *dst; struct net *net = dev_net(skb_dst(rxskb)->dev); struct dccp_v4_pernet *pn; struct sock *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; pn = net_generic(net, dccp_v4_pernet_id); ctl_sk = pn->v4_ctl_sk; 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, inet_sk(ctl_sk)->tos); 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; 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 = READ_ONCE(sk->sk_bound_dev_if); if (security_inet_conn_request(sk, skb, req)) goto drop_and_free; /* * 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, SK_RST_REASON_NOT_SPECIFIED); kfree_skb(skb); return 0; } EXPORT_SYMBOL_GPL(dccp_v4_do_rcv); /** * dccp_invalid_packet - check for malformed packets * @skb: Packet to validate * * 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 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, SK_RST_REASON_NOT_SPECIFIED); 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_ct(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, SK_RST_REASON_NOT_SPECIFIED); } 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), }; 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, }; static const struct net_protocol dccp_v4_protocol = { .handler = dccp_v4_rcv, .err_handler = dccp_v4_err, .no_policy = 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, .gettstamp = sock_gettstamp, /* 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, }; 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) { struct dccp_v4_pernet *pn = net_generic(net, dccp_v4_pernet_id); if (dccp_hashinfo.bhash == NULL) return -ESOCKTNOSUPPORT; return inet_ctl_sock_create(&pn->v4_ctl_sk, PF_INET, SOCK_DCCP, IPPROTO_DCCP, net); } static void __net_exit dccp_v4_exit_net(struct net *net) { struct dccp_v4_pernet *pn = net_generic(net, dccp_v4_pernet_id); inet_ctl_sock_destroy(pn->v4_ctl_sk); } static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list) { inet_twsk_purge(&dccp_hashinfo); } static struct pernet_operations dccp_v4_ops = { .init = dccp_v4_init_net, .exit = dccp_v4_exit_net, .exit_batch = dccp_v4_exit_batch, .id = &dccp_v4_pernet_id, .size = sizeof(struct dccp_v4_pernet), }; 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 "); MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");