| /* |
| * 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 "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) |
| { |
| struct inet_sock *inet = inet_sk(sk); |
| struct dccp_sock *dp = dccp_sk(sk); |
| const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; |
| __be16 orig_sport, orig_dport; |
| struct rtable *rt; |
| __be32 daddr, nexthop; |
| int tmp; |
| int err; |
| |
| 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; |
| if (inet->opt != NULL && inet->opt->srr) { |
| if (daddr == 0) |
| return -EINVAL; |
| nexthop = inet->opt->faddr; |
| } |
| |
| orig_sport = inet->inet_sport; |
| orig_dport = usin->sin_port; |
| tmp = ip_route_connect(&rt, nexthop, inet->inet_saddr, |
| RT_CONN_FLAGS(sk), sk->sk_bound_dev_if, |
| IPPROTO_DCCP, |
| orig_sport, orig_dport, sk, true); |
| if (tmp < 0) |
| return tmp; |
| |
| if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { |
| ip_rt_put(rt); |
| return -ENETUNREACH; |
| } |
| |
| if (inet->opt == NULL || !inet->opt->srr) |
| daddr = rt->rt_dst; |
| |
| if (inet->inet_saddr == 0) |
| inet->inet_saddr = rt->rt_src; |
| inet->inet_rcv_saddr = inet->inet_saddr; |
| |
| inet->inet_dport = usin->sin_port; |
| inet->inet_daddr = daddr; |
| |
| inet_csk(sk)->icsk_ext_hdr_len = 0; |
| if (inet->opt != NULL) |
| inet_csk(sk)->icsk_ext_hdr_len = inet->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; |
| |
| err = ip_route_newports(&rt, IPPROTO_DCCP, |
| orig_sport, orig_dport, |
| inet->inet_sport, inet->inet_dport, sk); |
| if (err != 0) |
| 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; |
| |
| /* We don't check in the destentry if pmtu discovery is forbidden |
| * on this route. We just assume that no packet_to_big packets |
| * are send back when pmtu discovery is not active. |
| * There is a small race when the user changes this flag in the |
| * route, but I think that's acceptable. |
| */ |
| if ((dst = __sk_dst_check(sk, 0)) == NULL) |
| return; |
| |
| dst->ops->update_pmtu(dst, mtu); |
| |
| /* 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 && |
| 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 */ |
| } |
| |
| /* |
| * 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_hdr *)(skb->data + offset); |
| 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); |
| |
| if (skb->len < offset + sizeof(*dh) || |
| skb->len < offset + __dccp_basic_hdr_len(dh)) { |
| ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
| return; |
| } |
| |
| sk = inet_lookup(net, &dccp_hashinfo, |
| iph->daddr, dh->dccph_dport, |
| iph->saddr, dh->dccph_sport, inet_iif(skb)); |
| if (sk == NULL) { |
| ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
| return; |
| } |
| |
| if (sk->sk_state == DCCP_TIME_WAIT) { |
| inet_twsk_put(inet_twsk(sk)); |
| return; |
| } |
| |
| 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_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); |
| |
| if (sk->sk_state == DCCP_CLOSED) |
| goto out; |
| |
| dp = dccp_sk(sk); |
| seq = dccp_hdr_seq(dh); |
| if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) && |
| !between48(seq, dp->dccps_awl, dp->dccps_awh)) { |
| NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); |
| goto out; |
| } |
| |
| switch (type) { |
| 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) { |
| struct request_sock *req , **prev; |
| case DCCP_LISTEN: |
| if (sock_owned_by_user(sk)) |
| goto out; |
| req = inet_csk_search_req(sk, &prev, dh->dccph_dport, |
| iph->daddr, iph->saddr); |
| if (!req) |
| goto out; |
| |
| /* |
| * ICMPs are not backlogged, hence we cannot get an established |
| * socket here. |
| */ |
| WARN_ON(req->sk); |
| |
| if (seq != dccp_rsk(req)->dreq_iss) { |
| NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); |
| goto out; |
| } |
| /* |
| * 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(sk, req, prev); |
| goto out; |
| |
| case DCCP_REQUESTING: |
| case DCCP_RESPOND: |
| if (!sock_owned_by_user(sk)) { |
| DCCP_INC_STATS_BH(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(struct sock *sk, struct sk_buff *skb, |
| struct request_sock *req, |
| struct dst_entry *dst) |
| { |
| struct inet_request_sock *ireq; |
| struct inet_sock *newinet; |
| struct sock *newsk; |
| |
| if (sk_acceptq_is_full(sk)) |
| goto exit_overflow; |
| |
| if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL) |
| goto exit; |
| |
| newsk = dccp_create_openreq_child(sk, req, skb); |
| if (newsk == NULL) |
| goto exit_nonewsk; |
| |
| sk_setup_caps(newsk, dst); |
| |
| newinet = inet_sk(newsk); |
| ireq = inet_rsk(req); |
| newinet->inet_daddr = ireq->rmt_addr; |
| newinet->inet_rcv_saddr = ireq->loc_addr; |
| newinet->inet_saddr = ireq->loc_addr; |
| newinet->opt = ireq->opt; |
| ireq->opt = NULL; |
| newinet->mc_index = inet_iif(skb); |
| newinet->mc_ttl = ip_hdr(skb)->ttl; |
| newinet->inet_id = jiffies; |
| |
| dccp_sync_mss(newsk, dst_mtu(dst)); |
| |
| if (__inet_inherit_port(sk, newsk) < 0) { |
| sock_put(newsk); |
| goto exit; |
| } |
| __inet_hash_nolisten(newsk, NULL); |
| |
| return newsk; |
| |
| exit_overflow: |
| NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); |
| exit_nonewsk: |
| dst_release(dst); |
| exit: |
| NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); |
| return NULL; |
| } |
| |
| EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock); |
| |
| static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb) |
| { |
| const struct dccp_hdr *dh = dccp_hdr(skb); |
| const struct iphdr *iph = ip_hdr(skb); |
| struct sock *nsk; |
| struct request_sock **prev; |
| /* Find possible connection requests. */ |
| struct request_sock *req = inet_csk_search_req(sk, &prev, |
| dh->dccph_sport, |
| iph->saddr, iph->daddr); |
| if (req != NULL) |
| return dccp_check_req(sk, skb, req, prev); |
| |
| nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo, |
| iph->saddr, dh->dccph_sport, |
| iph->daddr, dh->dccph_dport, |
| inet_iif(skb)); |
| if (nsk != NULL) { |
| if (nsk->sk_state != DCCP_TIME_WAIT) { |
| bh_lock_sock(nsk); |
| return nsk; |
| } |
| inet_twsk_put(inet_twsk(nsk)); |
| return NULL; |
| } |
| |
| return sk; |
| } |
| |
| static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk, |
| struct sk_buff *skb) |
| { |
| struct rtable *rt; |
| struct flowi fl = { .oif = skb_rtable(skb)->rt_iif, |
| .fl4_dst = ip_hdr(skb)->saddr, |
| .fl4_src = ip_hdr(skb)->daddr, |
| .fl4_tos = RT_CONN_FLAGS(sk), |
| .proto = sk->sk_protocol, |
| .fl_ip_sport = dccp_hdr(skb)->dccph_dport, |
| .fl_ip_dport = dccp_hdr(skb)->dccph_sport |
| }; |
| |
| security_skb_classify_flow(skb, &fl); |
| if (ip_route_output_flow(net, &rt, &fl, sk, 0)) { |
| IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES); |
| return NULL; |
| } |
| |
| return &rt->dst; |
| } |
| |
| static int dccp_v4_send_response(struct sock *sk, struct request_sock *req, |
| struct request_values *rv_unused) |
| { |
| int err = -1; |
| struct sk_buff *skb; |
| struct dst_entry *dst; |
| |
| dst = inet_csk_route_req(sk, 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->loc_addr, |
| ireq->rmt_addr); |
| err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr, |
| ireq->rmt_addr, |
| ireq->opt); |
| err = net_xmit_eval(err); |
| } |
| |
| out: |
| dst_release(dst); |
| return err; |
| } |
| |
| static void dccp_v4_ctl_send_reset(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)); |
| |
| 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_BH(DCCP_MIB_OUTSEGS); |
| DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS); |
| } |
| out: |
| dst_release(dst); |
| } |
| |
| static void dccp_v4_reqsk_destructor(struct request_sock *req) |
| { |
| dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg); |
| kfree(inet_rsk(req)->opt); |
| } |
| |
| 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, |
| }; |
| |
| 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; |
| |
| /* |
| * Accept backlog is full. If we have already queued enough |
| * of warm entries in syn queue, drop request. It is better than |
| * clogging syn queue with openreqs with exponentially increasing |
| * timeout. |
| */ |
| if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) |
| goto drop; |
| |
| req = inet_reqsk_alloc(&dccp_request_sock_ops); |
| 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); |
| ireq->loc_addr = ip_hdr(skb)->daddr; |
| ireq->rmt_addr = ip_hdr(skb)->saddr; |
| |
| /* |
| * Step 3: Process LISTEN state |
| * |
| * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie |
| * |
| * In fact we defer setting S.GSR, S.SWL, S.SWH to |
| * dccp_create_openreq_child. |
| */ |
| dreq->dreq_isr = dcb->dccpd_seq; |
| dreq->dreq_iss = dccp_v4_init_sequence(skb); |
| dreq->dreq_service = service; |
| |
| if (dccp_v4_send_response(sk, req, NULL)) |
| goto drop_and_free; |
| |
| inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT); |
| return 0; |
| |
| drop_and_free: |
| reqsk_free(req); |
| drop: |
| DCCP_INC_STATS_BH(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 (sk->sk_state == DCCP_LISTEN) { |
| struct sock *nsk = dccp_v4_hnd_req(sk, skb); |
| |
| if (nsk == NULL) |
| goto discard; |
| |
| if (nsk != sk) { |
| if (dccp_child_process(sk, nsk, skb)) |
| goto reset; |
| return 0; |
| } |
| } |
| |
| if (dccp_rcv_state_process(sk, skb, dh, skb->len)) |
| goto reset; |
| return 0; |
| |
| reset: |
| dccp_v4_ctl_send_reset(sk, skb); |
| discard: |
| 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; |
| |
| 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 |
| */ |
| if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) { |
| DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff); |
| return 1; |
| } |
| /* |
| * If P.Data Offset is too too large for packet, drop packet and return |
| */ |
| if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) { |
| DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff); |
| return 1; |
| } |
| |
| /* |
| * 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; |
| 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); |
| } |
| |
| /* Step 2: |
| * Look up flow ID in table and get corresponding socket */ |
| sk = __inet_lookup_skb(&dccp_hashinfo, skb, |
| dh->dccph_sport, dh->dccph_dport); |
| /* |
| * Step 2: |
| * If no socket ... |
| */ |
| if (sk == NULL) { |
| 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; |
| } |
| |
| /* |
| * 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); |
| |
| 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: |
| 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), |
| .bind_conflict = inet_csk_bind_conflict, |
| #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_DESTROY_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, |
| }; |
| |
| 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, |
| .no_check = 0, |
| .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 struct pernet_operations dccp_v4_ops = { |
| .init = dccp_v4_init_net, |
| .exit = dccp_v4_exit_net, |
| }; |
| |
| static int __init dccp_v4_init(void) |
| { |
| int err = proto_register(&dccp_v4_prot, 1); |
| |
| if (err != 0) |
| goto out; |
| |
| err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP); |
| if (err != 0) |
| goto out_proto_unregister; |
| |
| inet_register_protosw(&dccp_v4_protosw); |
| |
| err = register_pernet_subsys(&dccp_v4_ops); |
| if (err) |
| goto out_destroy_ctl_sock; |
| out: |
| return err; |
| out_destroy_ctl_sock: |
| inet_unregister_protosw(&dccp_v4_protosw); |
| inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP); |
| out_proto_unregister: |
| proto_unregister(&dccp_v4_prot); |
| goto out; |
| } |
| |
| static void __exit dccp_v4_exit(void) |
| { |
| unregister_pernet_subsys(&dccp_v4_ops); |
| inet_unregister_protosw(&dccp_v4_protosw); |
| inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP); |
| 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"); |