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); if (sk->sk_state == DCCP_LISTEN) return; if ((dst = __sk_dst_check(sk, 0)) == NULL) return; dst->ops->update_pmtu(dst, mtu); 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); dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC); } }
static int dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb) { int queued = 0; /* * Step 7: Check for unexpected packet types * If (S.is_server and P.type == CloseReq) * Send Sync packet acknowledging P.seqno * Drop packet and return */ if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) { dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); return queued; } /* Step 13: process relevant Client states < CLOSEREQ */ switch (sk->sk_state) { case DCCP_REQUESTING: dccp_send_close(sk, 0); dccp_set_state(sk, DCCP_CLOSING); break; case DCCP_OPEN: case DCCP_PARTOPEN: /* Give waiting application a chance to read pending data */ queued = 1; dccp_fin(sk, skb); dccp_set_state(sk, DCCP_PASSIVE_CLOSEREQ); /* fall through */ case DCCP_PASSIVE_CLOSEREQ: sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); } return queued; }
/** * dccp_xmit_packet - Send data packet under control of CCID * Transmits next-queued payload and informs CCID to account for the packet. */ static void dccp_xmit_packet(struct sock *sk) { int err, len; struct dccp_sock *dp = dccp_sk(sk); struct sk_buff *skb = dccp_qpolicy_pop(sk); if (unlikely(skb == NULL)) return; len = skb->len; if (sk->sk_state == DCCP_PARTOPEN) { const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD; /* * See 8.1.5 - Handshake Completion. * * For robustness we resend Confirm options until the client has * entered OPEN. During the initial feature negotiation, the MPS * is smaller than usual, reduced by the Change/Confirm options. */ if (!list_empty(&dp->dccps_featneg) && len > cur_mps) { DCCP_WARN("Payload too large (%d) for featneg.\n", len); dccp_send_ack(sk); dccp_feat_list_purge(&dp->dccps_featneg); } inet_csk_schedule_ack(sk); inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, inet_csk(sk)->icsk_rto, DCCP_RTO_MAX); DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK; } else if (dccp_ack_pending(sk)) { DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK; } else { DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATA; } err = dccp_transmit_skb(sk, skb); if (err) dccp_pr_debug("transmit_skb() returned err=%d\n", err); /* * Register this one as sent even if an error occurred. To the remote * end a local packet drop is indistinguishable from network loss, i.e. * any local drop will eventually be reported via receiver feedback. */ ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, len); /* * If the CCID needs to transfer additional header options out-of-band * (e.g. Ack Vectors or feature-negotiation options), it activates this * flag to schedule a Sync. The Sync will automatically incorporate all * currently pending header options, thus clearing the backlog. */ if (dp->dccps_sync_scheduled) dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC); }
/* * 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 */ }
static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb) { /* * Step 7: Check for unexpected packet types * If (S.is_server and P.type == CloseReq) * Send Sync packet acknowledging P.seqno * Drop packet and return */ if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) { dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); return; } if (sk->sk_state != DCCP_CLOSING) dccp_set_state(sk, DCCP_CLOSING); dccp_send_close(sk, 0); }
/* * 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 int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) { const struct dccp_hdr *dh = dccp_hdr(skb); struct dccp_sock *dp = dccp_sk(sk); u64 lswl, lawl; /* * Step 5: Prepare sequence numbers for Sync * If P.type == Sync or P.type == SyncAck, * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL, * / * P is valid, so update sequence number variables * accordingly. After this update, P will pass the tests * in Step 6. A SyncAck is generated if necessary in * Step 15 * / * Update S.GSR, S.SWL, S.SWH * Otherwise, * Drop packet and return */ if (dh->dccph_type == DCCP_PKT_SYNC || dh->dccph_type == DCCP_PKT_SYNCACK) { if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, dp->dccps_awl, dp->dccps_awh) && !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl)) dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq); else return -1; } /* * Step 6: Check sequence numbers * Let LSWL = S.SWL and LAWL = S.AWL * If P.type == CloseReq or P.type == Close or P.type == Reset, * LSWL := S.GSR + 1, LAWL := S.GAR * If LSWL <= P.seqno <= S.SWH * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH), * Update S.GSR, S.SWL, S.SWH * If P.type != Sync, * Update S.GAR * Otherwise, * Send Sync packet acknowledging P.seqno * Drop packet and return */ lswl = dp->dccps_swl; lawl = dp->dccps_awl; if (dh->dccph_type == DCCP_PKT_CLOSEREQ || dh->dccph_type == DCCP_PKT_CLOSE || dh->dccph_type == DCCP_PKT_RESET) { lswl = dp->dccps_gsr; dccp_inc_seqno(&lswl); lawl = dp->dccps_gar; } if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) && (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ || between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, lawl, dp->dccps_awh))) { dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq); if (dh->dccph_type != DCCP_PKT_SYNC && (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)) dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq; } else { DCCP_WARN("DCCP: Step 6 failed for %s packet, " "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and " "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), " "sending SYNC...\n", dccp_packet_name(dh->dccph_type), (unsigned long long) lswl, (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq, (unsigned long long) dp->dccps_swh, (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists", (unsigned long long) lawl, (unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq, (unsigned long long) dp->dccps_awh); dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); return -1; } return 0; }
int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, struct dccp_hdr *dh, unsigned len) { struct dccp_sock *dp = dccp_sk(sk); struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); const int old_state = sk->sk_state; int queued = 0; /* * Step 3: Process LISTEN state * * If S.state == LISTEN, * 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 */ if (sk->sk_state == DCCP_LISTEN) { if (dh->dccph_type == DCCP_PKT_REQUEST) { if (inet_csk(sk)->icsk_af_ops->conn_request(sk, skb) < 0) return 1; /* FIXME: do congestion control initialization */ goto discard; } if (dh->dccph_type == DCCP_PKT_RESET) goto discard; /* Caller (dccp_v4_do_rcv) will send Reset */ dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; return 1; } if (sk->sk_state != DCCP_REQUESTING) { if (dccp_check_seqno(sk, skb)) goto discard; /* * Step 8: Process options and mark acknowledgeable */ if (dccp_parse_options(sk, skb)) goto discard; if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) dccp_event_ack_recv(sk, skb); if (dccp_msk(sk)->dccpms_send_ack_vector && dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_ACKVEC_STATE_RECEIVED)) goto discard; /* XXX see the comments in dccp_rcv_established about this */ if (dccp_sk(sk)->dccps_role == DCCP_ROLE_SERVER) ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); else ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); } /* * Step 9: Process Reset * If P.type == Reset, * Tear down connection * S.state := TIMEWAIT * Set TIMEWAIT timer * Drop packet and return */ if (dh->dccph_type == DCCP_PKT_RESET) { /* * Queue the equivalent of TCP fin so that dccp_recvmsg * exits the loop */ dccp_fin(sk, skb); dccp_time_wait(sk, DCCP_TIME_WAIT, 0); return 0; /* * Step 7: Check for unexpected packet types * If (S.is_server and P.type == CloseReq) * or (S.is_server and P.type == Response) * or (S.is_client and P.type == Request) * or (S.state == RESPOND and P.type == Data), * Send Sync packet acknowledging P.seqno * Drop packet and return */ } else if ((dp->dccps_role != DCCP_ROLE_CLIENT && (dh->dccph_type == DCCP_PKT_RESPONSE || dh->dccph_type == DCCP_PKT_CLOSEREQ)) || (dp->dccps_role == DCCP_ROLE_CLIENT && dh->dccph_type == DCCP_PKT_REQUEST) || (sk->sk_state == DCCP_RESPOND && dh->dccph_type == DCCP_PKT_DATA)) { dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC); goto discard; } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { dccp_rcv_closereq(sk, skb); goto discard; } else if (dh->dccph_type == DCCP_PKT_CLOSE) { dccp_rcv_close(sk, skb); return 0; } if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) { dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK); goto discard; } switch (sk->sk_state) { case DCCP_CLOSED: dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; return 1; case DCCP_REQUESTING: /* FIXME: do congestion control initialization */ queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len); if (queued >= 0) return queued; __kfree_skb(skb); return 0; case DCCP_RESPOND: case DCCP_PARTOPEN: queued = dccp_rcv_respond_partopen_state_process(sk, skb, dh, len); break; } if (dh->dccph_type == DCCP_PKT_ACK || dh->dccph_type == DCCP_PKT_DATAACK) { switch (old_state) { case DCCP_PARTOPEN: sk->sk_state_change(sk); sk_wake_async(sk, 0, POLL_OUT); break; } } if (!queued) { discard: __kfree_skb(skb); } return 0; }
static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb, const struct dccp_hdr *dh, const unsigned len) { struct dccp_sock *dp = dccp_sk(sk); switch (dccp_hdr(skb)->dccph_type) { case DCCP_PKT_DATAACK: case DCCP_PKT_DATA: /* * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED * option if it is. */ __skb_pull(skb, dh->dccph_doff * 4); __skb_queue_tail(&sk->sk_receive_queue, skb); skb_set_owner_r(skb, sk); sk->sk_data_ready(sk, 0); return 0; case DCCP_PKT_ACK: goto discard; case DCCP_PKT_RESET: /* * Step 9: Process Reset * If P.type == Reset, * Tear down connection * S.state := TIMEWAIT * Set TIMEWAIT timer * Drop packet and return */ dccp_fin(sk, skb); dccp_time_wait(sk, DCCP_TIME_WAIT, 0); return 0; case DCCP_PKT_CLOSEREQ: dccp_rcv_closereq(sk, skb); goto discard; case DCCP_PKT_CLOSE: dccp_rcv_close(sk, skb); return 0; case DCCP_PKT_REQUEST: /* Step 7 * or (S.is_server and P.type == Response) * or (S.is_client and P.type == Request) * or (S.state >= OPEN and P.type == Request * and P.seqno >= S.OSR) * or (S.state >= OPEN and P.type == Response * and P.seqno >= S.OSR) * or (S.state == RESPOND and P.type == Data), * Send Sync packet acknowledging P.seqno * Drop packet and return */ if (dp->dccps_role != DCCP_ROLE_LISTEN) goto send_sync; goto check_seq; case DCCP_PKT_RESPONSE: if (dp->dccps_role != DCCP_ROLE_CLIENT) goto send_sync; check_seq: if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) { send_sync: dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); } break; case DCCP_PKT_SYNC: dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNCACK); /* * From RFC 4340, sec. 5.7 * * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets * MAY have non-zero-length application data areas, whose * contents receivers MUST ignore. */ goto discard; } DCCP_INC_STATS_BH(DCCP_MIB_INERRS); discard: __kfree_skb(skb); return 0; }