mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
739 lines
22 KiB
739 lines
22 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* net/dccp/input.c |
|
* |
|
* An implementation of the DCCP protocol |
|
* Arnaldo Carvalho de Melo <[email protected]> |
|
*/ |
|
|
|
#include <linux/dccp.h> |
|
#include <linux/skbuff.h> |
|
#include <linux/slab.h> |
|
|
|
#include <net/sock.h> |
|
|
|
#include "ackvec.h" |
|
#include "ccid.h" |
|
#include "dccp.h" |
|
|
|
/* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */ |
|
int sysctl_dccp_sync_ratelimit __read_mostly = HZ / 8; |
|
|
|
static void dccp_enqueue_skb(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
__skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4); |
|
__skb_queue_tail(&sk->sk_receive_queue, skb); |
|
skb_set_owner_r(skb, sk); |
|
sk->sk_data_ready(sk); |
|
} |
|
|
|
static void dccp_fin(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
/* |
|
* On receiving Close/CloseReq, both RD/WR shutdown are performed. |
|
* RFC 4340, 8.3 says that we MAY send further Data/DataAcks after |
|
* receiving the closing segment, but there is no guarantee that such |
|
* data will be processed at all. |
|
*/ |
|
sk->sk_shutdown = SHUTDOWN_MASK; |
|
sock_set_flag(sk, SOCK_DONE); |
|
dccp_enqueue_skb(sk, skb); |
|
} |
|
|
|
static int dccp_rcv_close(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
int queued = 0; |
|
|
|
switch (sk->sk_state) { |
|
/* |
|
* We ignore Close when received in one of the following states: |
|
* - CLOSED (may be a late or duplicate packet) |
|
* - PASSIVE_CLOSEREQ (the peer has sent a CloseReq earlier) |
|
* - RESPOND (already handled by dccp_check_req) |
|
*/ |
|
case DCCP_CLOSING: |
|
/* |
|
* Simultaneous-close: receiving a Close after sending one. This |
|
* can happen if both client and server perform active-close and |
|
* will result in an endless ping-pong of crossing and retrans- |
|
* mitted Close packets, which only terminates when one of the |
|
* nodes times out (min. 64 seconds). Quicker convergence can be |
|
* achieved when one of the nodes acts as tie-breaker. |
|
* This is ok as both ends are done with data transfer and each |
|
* end is just waiting for the other to acknowledge termination. |
|
*/ |
|
if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) |
|
break; |
|
fallthrough; |
|
case DCCP_REQUESTING: |
|
case DCCP_ACTIVE_CLOSEREQ: |
|
dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED); |
|
dccp_done(sk); |
|
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_CLOSE); |
|
fallthrough; |
|
case DCCP_PASSIVE_CLOSE: |
|
/* |
|
* Retransmitted Close: we have already enqueued the first one. |
|
*/ |
|
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); |
|
} |
|
return queued; |
|
} |
|
|
|
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); |
|
fallthrough; |
|
case DCCP_PASSIVE_CLOSEREQ: |
|
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); |
|
} |
|
return queued; |
|
} |
|
|
|
static u16 dccp_reset_code_convert(const u8 code) |
|
{ |
|
static const u16 error_code[] = { |
|
[DCCP_RESET_CODE_CLOSED] = 0, /* normal termination */ |
|
[DCCP_RESET_CODE_UNSPECIFIED] = 0, /* nothing known */ |
|
[DCCP_RESET_CODE_ABORTED] = ECONNRESET, |
|
|
|
[DCCP_RESET_CODE_NO_CONNECTION] = ECONNREFUSED, |
|
[DCCP_RESET_CODE_CONNECTION_REFUSED] = ECONNREFUSED, |
|
[DCCP_RESET_CODE_TOO_BUSY] = EUSERS, |
|
[DCCP_RESET_CODE_AGGRESSION_PENALTY] = EDQUOT, |
|
|
|
[DCCP_RESET_CODE_PACKET_ERROR] = ENOMSG, |
|
[DCCP_RESET_CODE_BAD_INIT_COOKIE] = EBADR, |
|
[DCCP_RESET_CODE_BAD_SERVICE_CODE] = EBADRQC, |
|
[DCCP_RESET_CODE_OPTION_ERROR] = EILSEQ, |
|
[DCCP_RESET_CODE_MANDATORY_ERROR] = EOPNOTSUPP, |
|
}; |
|
|
|
return code >= DCCP_MAX_RESET_CODES ? 0 : error_code[code]; |
|
} |
|
|
|
static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
u16 err = dccp_reset_code_convert(dccp_hdr_reset(skb)->dccph_reset_code); |
|
|
|
sk->sk_err = err; |
|
|
|
/* Queue the equivalent of TCP fin so that dccp_recvmsg exits the loop */ |
|
dccp_fin(sk, skb); |
|
|
|
if (err && !sock_flag(sk, SOCK_DEAD)) |
|
sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR); |
|
dccp_time_wait(sk, DCCP_TIME_WAIT, 0); |
|
} |
|
|
|
static void dccp_handle_ackvec_processing(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
struct dccp_ackvec *av = dccp_sk(sk)->dccps_hc_rx_ackvec; |
|
|
|
if (av == NULL) |
|
return; |
|
if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) |
|
dccp_ackvec_clear_state(av, DCCP_SKB_CB(skb)->dccpd_ack_seq); |
|
dccp_ackvec_input(av, skb); |
|
} |
|
|
|
static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
const struct dccp_sock *dp = dccp_sk(sk); |
|
|
|
/* Don't deliver to RX CCID when node has shut down read end. */ |
|
if (!(sk->sk_shutdown & RCV_SHUTDOWN)) |
|
ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); |
|
/* |
|
* Until the TX queue has been drained, we can not honour SHUT_WR, since |
|
* we need received feedback as input to adjust congestion control. |
|
*/ |
|
if (sk->sk_write_queue.qlen > 0 || !(sk->sk_shutdown & SEND_SHUTDOWN)) |
|
ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); |
|
} |
|
|
|
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, seqno = DCCP_SKB_CB(skb)->dccpd_seq, |
|
ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; |
|
|
|
/* |
|
* 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(ackno, dp->dccps_awl, dp->dccps_awh) && |
|
dccp_delta_seqno(dp->dccps_swl, seqno) >= 0) |
|
dccp_update_gsr(sk, seqno); |
|
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 |
|
*/ |
|
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 = ADD48(dp->dccps_gsr, 1); |
|
lawl = dp->dccps_gar; |
|
} |
|
|
|
if (between48(seqno, lswl, dp->dccps_swh) && |
|
(ackno == DCCP_PKT_WITHOUT_ACK_SEQ || |
|
between48(ackno, lawl, dp->dccps_awh))) { |
|
dccp_update_gsr(sk, seqno); |
|
|
|
if (dh->dccph_type != DCCP_PKT_SYNC && |
|
ackno != DCCP_PKT_WITHOUT_ACK_SEQ && |
|
after48(ackno, dp->dccps_gar)) |
|
dp->dccps_gar = ackno; |
|
} else { |
|
unsigned long now = jiffies; |
|
/* |
|
* Step 6: Check sequence numbers |
|
* Otherwise, |
|
* If P.type == Reset, |
|
* Send Sync packet acknowledging S.GSR |
|
* Otherwise, |
|
* Send Sync packet acknowledging P.seqno |
|
* Drop packet and return |
|
* |
|
* These Syncs are rate-limited as per RFC 4340, 7.5.4: |
|
* at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second. |
|
*/ |
|
if (time_before(now, (dp->dccps_rate_last + |
|
sysctl_dccp_sync_ratelimit))) |
|
return -1; |
|
|
|
DCCP_WARN("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) seqno, |
|
(unsigned long long) dp->dccps_swh, |
|
(ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" |
|
: "exists", |
|
(unsigned long long) lawl, (unsigned long long) ackno, |
|
(unsigned long long) dp->dccps_awh); |
|
|
|
dp->dccps_rate_last = now; |
|
|
|
if (dh->dccph_type == DCCP_PKT_RESET) |
|
seqno = dp->dccps_gsr; |
|
dccp_send_sync(sk, seqno, DCCP_PKT_SYNC); |
|
return -1; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
|
const struct dccp_hdr *dh, const unsigned int len) |
|
{ |
|
struct dccp_sock *dp = dccp_sk(sk); |
|
|
|
switch (dccp_hdr(skb)->dccph_type) { |
|
case DCCP_PKT_DATAACK: |
|
case DCCP_PKT_DATA: |
|
/* |
|
* FIXME: schedule DATA_DROPPED (RFC 4340, 11.7.2) if and when |
|
* - sk_shutdown == RCV_SHUTDOWN, use Code 1, "Not Listening" |
|
* - sk_receive_queue is full, use Code 2, "Receive Buffer" |
|
*/ |
|
dccp_enqueue_skb(sk, skb); |
|
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_rcv_reset(sk, skb); |
|
return 0; |
|
case DCCP_PKT_CLOSEREQ: |
|
if (dccp_rcv_closereq(sk, skb)) |
|
return 0; |
|
goto discard; |
|
case DCCP_PKT_CLOSE: |
|
if (dccp_rcv_close(sk, skb)) |
|
return 0; |
|
goto discard; |
|
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 (dccp_delta_seqno(dp->dccps_osr, |
|
DCCP_SKB_CB(skb)->dccpd_seq) >= 0) { |
|
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(DCCP_MIB_INERRS); |
|
discard: |
|
__kfree_skb(skb); |
|
return 0; |
|
} |
|
|
|
int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
|
const struct dccp_hdr *dh, const unsigned int len) |
|
{ |
|
if (dccp_check_seqno(sk, skb)) |
|
goto discard; |
|
|
|
if (dccp_parse_options(sk, NULL, skb)) |
|
return 1; |
|
|
|
dccp_handle_ackvec_processing(sk, skb); |
|
dccp_deliver_input_to_ccids(sk, skb); |
|
|
|
return __dccp_rcv_established(sk, skb, dh, len); |
|
discard: |
|
__kfree_skb(skb); |
|
return 0; |
|
} |
|
|
|
EXPORT_SYMBOL_GPL(dccp_rcv_established); |
|
|
|
static int dccp_rcv_request_sent_state_process(struct sock *sk, |
|
struct sk_buff *skb, |
|
const struct dccp_hdr *dh, |
|
const unsigned int len) |
|
{ |
|
/* |
|
* Step 4: Prepare sequence numbers in REQUEST |
|
* If S.state == REQUEST, |
|
* If (P.type == Response or P.type == Reset) |
|
* and S.AWL <= P.ackno <= S.AWH, |
|
* / * Set sequence number variables corresponding to the |
|
* other endpoint, so P will pass the tests in Step 6 * / |
|
* Set S.GSR, S.ISR, S.SWL, S.SWH |
|
* / * Response processing continues in Step 10; Reset |
|
* processing continues in Step 9 * / |
|
*/ |
|
if (dh->dccph_type == DCCP_PKT_RESPONSE) { |
|
const struct inet_connection_sock *icsk = inet_csk(sk); |
|
struct dccp_sock *dp = dccp_sk(sk); |
|
long tstamp = dccp_timestamp(); |
|
|
|
if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, |
|
dp->dccps_awl, dp->dccps_awh)) { |
|
dccp_pr_debug("invalid ackno: S.AWL=%llu, " |
|
"P.ackno=%llu, S.AWH=%llu\n", |
|
(unsigned long long)dp->dccps_awl, |
|
(unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq, |
|
(unsigned long long)dp->dccps_awh); |
|
goto out_invalid_packet; |
|
} |
|
|
|
/* |
|
* If option processing (Step 8) failed, return 1 here so that |
|
* dccp_v4_do_rcv() sends a Reset. The Reset code depends on |
|
* the option type and is set in dccp_parse_options(). |
|
*/ |
|
if (dccp_parse_options(sk, NULL, skb)) |
|
return 1; |
|
|
|
/* Obtain usec RTT sample from SYN exchange (used by TFRC). */ |
|
if (likely(dp->dccps_options_received.dccpor_timestamp_echo)) |
|
dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp - |
|
dp->dccps_options_received.dccpor_timestamp_echo)); |
|
|
|
/* Stop the REQUEST timer */ |
|
inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); |
|
WARN_ON(sk->sk_send_head == NULL); |
|
kfree_skb(sk->sk_send_head); |
|
sk->sk_send_head = NULL; |
|
|
|
/* |
|
* Set ISR, GSR from packet. ISS was set in dccp_v{4,6}_connect |
|
* and GSS in dccp_transmit_skb(). Setting AWL/AWH and SWL/SWH |
|
* is done as part of activating the feature values below, since |
|
* these settings depend on the local/remote Sequence Window |
|
* features, which were undefined or not confirmed until now. |
|
*/ |
|
dp->dccps_gsr = dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; |
|
|
|
dccp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
|
|
|
/* |
|
* Step 10: Process REQUEST state (second part) |
|
* If S.state == REQUEST, |
|
* / * If we get here, P is a valid Response from the |
|
* server (see Step 4), and we should move to |
|
* PARTOPEN state. PARTOPEN means send an Ack, |
|
* don't send Data packets, retransmit Acks |
|
* periodically, and always include any Init Cookie |
|
* from the Response * / |
|
* S.state := PARTOPEN |
|
* Set PARTOPEN timer |
|
* Continue with S.state == PARTOPEN |
|
* / * Step 12 will send the Ack completing the |
|
* three-way handshake * / |
|
*/ |
|
dccp_set_state(sk, DCCP_PARTOPEN); |
|
|
|
/* |
|
* If feature negotiation was successful, activate features now; |
|
* an activation failure means that this host could not activate |
|
* one ore more features (e.g. insufficient memory), which would |
|
* leave at least one feature in an undefined state. |
|
*/ |
|
if (dccp_feat_activate_values(sk, &dp->dccps_featneg)) |
|
goto unable_to_proceed; |
|
|
|
/* Make sure socket is routed, for correct metrics. */ |
|
icsk->icsk_af_ops->rebuild_header(sk); |
|
|
|
if (!sock_flag(sk, SOCK_DEAD)) { |
|
sk->sk_state_change(sk); |
|
sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); |
|
} |
|
|
|
if (sk->sk_write_pending || inet_csk_in_pingpong_mode(sk) || |
|
icsk->icsk_accept_queue.rskq_defer_accept) { |
|
/* Save one ACK. Data will be ready after |
|
* several ticks, if write_pending is set. |
|
* |
|
* It may be deleted, but with this feature tcpdumps |
|
* look so _wonderfully_ clever, that I was not able |
|
* to stand against the temptation 8) --ANK |
|
*/ |
|
/* |
|
* OK, in DCCP we can as well do a similar trick, its |
|
* even in the draft, but there is no need for us to |
|
* schedule an ack here, as dccp_sendmsg does this for |
|
* us, also stated in the draft. -acme |
|
*/ |
|
__kfree_skb(skb); |
|
return 0; |
|
} |
|
dccp_send_ack(sk); |
|
return -1; |
|
} |
|
|
|
out_invalid_packet: |
|
/* dccp_v4_do_rcv will send a reset */ |
|
DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; |
|
return 1; |
|
|
|
unable_to_proceed: |
|
DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_ABORTED; |
|
/* |
|
* We mark this socket as no longer usable, so that the loop in |
|
* dccp_sendmsg() terminates and the application gets notified. |
|
*/ |
|
dccp_set_state(sk, DCCP_CLOSED); |
|
sk->sk_err = ECOMM; |
|
return 1; |
|
} |
|
|
|
static int dccp_rcv_respond_partopen_state_process(struct sock *sk, |
|
struct sk_buff *skb, |
|
const struct dccp_hdr *dh, |
|
const unsigned int len) |
|
{ |
|
struct dccp_sock *dp = dccp_sk(sk); |
|
u32 sample = dp->dccps_options_received.dccpor_timestamp_echo; |
|
int queued = 0; |
|
|
|
switch (dh->dccph_type) { |
|
case DCCP_PKT_RESET: |
|
inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); |
|
break; |
|
case DCCP_PKT_DATA: |
|
if (sk->sk_state == DCCP_RESPOND) |
|
break; |
|
fallthrough; |
|
case DCCP_PKT_DATAACK: |
|
case DCCP_PKT_ACK: |
|
/* |
|
* FIXME: we should be resetting the PARTOPEN (DELACK) timer |
|
* here but only if we haven't used the DELACK timer for |
|
* something else, like sending a delayed ack for a TIMESTAMP |
|
* echo, etc, for now were not clearing it, sending an extra |
|
* ACK when there is nothing else to do in DELACK is not a big |
|
* deal after all. |
|
*/ |
|
|
|
/* Stop the PARTOPEN timer */ |
|
if (sk->sk_state == DCCP_PARTOPEN) |
|
inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); |
|
|
|
/* Obtain usec RTT sample from SYN exchange (used by TFRC). */ |
|
if (likely(sample)) { |
|
long delta = dccp_timestamp() - sample; |
|
|
|
dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * delta); |
|
} |
|
|
|
dp->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq; |
|
dccp_set_state(sk, DCCP_OPEN); |
|
|
|
if (dh->dccph_type == DCCP_PKT_DATAACK || |
|
dh->dccph_type == DCCP_PKT_DATA) { |
|
__dccp_rcv_established(sk, skb, dh, len); |
|
queued = 1; /* packet was queued |
|
(by __dccp_rcv_established) */ |
|
} |
|
break; |
|
} |
|
|
|
return queued; |
|
} |
|
|
|
int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, |
|
struct dccp_hdr *dh, unsigned int len) |
|
{ |
|
struct dccp_sock *dp = dccp_sk(sk); |
|
struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
|
const int old_state = sk->sk_state; |
|
bool acceptable; |
|
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) { |
|
/* It is possible that we process SYN packets from backlog, |
|
* so we need to make sure to disable BH and RCU right there. |
|
*/ |
|
rcu_read_lock(); |
|
local_bh_disable(); |
|
acceptable = inet_csk(sk)->icsk_af_ops->conn_request(sk, skb) >= 0; |
|
local_bh_enable(); |
|
rcu_read_unlock(); |
|
if (!acceptable) |
|
return 1; |
|
consume_skb(skb); |
|
return 0; |
|
} |
|
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; |
|
} else if (sk->sk_state == DCCP_CLOSED) { |
|
dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; |
|
return 1; |
|
} |
|
|
|
/* Step 6: Check sequence numbers (omitted in LISTEN/REQUEST state) */ |
|
if (sk->sk_state != DCCP_REQUESTING && dccp_check_seqno(sk, skb)) |
|
goto discard; |
|
|
|
/* |
|
* Step 7: Check for unexpected packet types |
|
* If (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 |
|
*/ |
|
if ((dp->dccps_role != DCCP_ROLE_CLIENT && |
|
dh->dccph_type == DCCP_PKT_RESPONSE) || |
|
(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; |
|
} |
|
|
|
/* Step 8: Process options */ |
|
if (dccp_parse_options(sk, NULL, skb)) |
|
return 1; |
|
|
|
/* |
|
* 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) { |
|
dccp_rcv_reset(sk, skb); |
|
return 0; |
|
} else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { /* Step 13 */ |
|
if (dccp_rcv_closereq(sk, skb)) |
|
return 0; |
|
goto discard; |
|
} else if (dh->dccph_type == DCCP_PKT_CLOSE) { /* Step 14 */ |
|
if (dccp_rcv_close(sk, skb)) |
|
return 0; |
|
goto discard; |
|
} |
|
|
|
switch (sk->sk_state) { |
|
case DCCP_REQUESTING: |
|
queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len); |
|
if (queued >= 0) |
|
return queued; |
|
|
|
__kfree_skb(skb); |
|
return 0; |
|
|
|
case DCCP_PARTOPEN: |
|
/* Step 8: if using Ack Vectors, mark packet acknowledgeable */ |
|
dccp_handle_ackvec_processing(sk, skb); |
|
dccp_deliver_input_to_ccids(sk, skb); |
|
fallthrough; |
|
case DCCP_RESPOND: |
|
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, SOCK_WAKE_IO, POLL_OUT); |
|
break; |
|
} |
|
} else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) { |
|
dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK); |
|
goto discard; |
|
} |
|
|
|
if (!queued) { |
|
discard: |
|
__kfree_skb(skb); |
|
} |
|
return 0; |
|
} |
|
|
|
EXPORT_SYMBOL_GPL(dccp_rcv_state_process); |
|
|
|
/** |
|
* dccp_sample_rtt - Validate and finalise computation of RTT sample |
|
* @sk: socket structure |
|
* @delta: number of microseconds between packet and acknowledgment |
|
* |
|
* The routine is kept generic to work in different contexts. It should be |
|
* called immediately when the ACK used for the RTT sample arrives. |
|
*/ |
|
u32 dccp_sample_rtt(struct sock *sk, long delta) |
|
{ |
|
/* dccpor_elapsed_time is either zeroed out or set and > 0 */ |
|
delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10; |
|
|
|
if (unlikely(delta <= 0)) { |
|
DCCP_WARN("unusable RTT sample %ld, using min\n", delta); |
|
return DCCP_SANE_RTT_MIN; |
|
} |
|
if (unlikely(delta > DCCP_SANE_RTT_MAX)) { |
|
DCCP_WARN("RTT sample %ld too large, using max\n", delta); |
|
return DCCP_SANE_RTT_MAX; |
|
} |
|
|
|
return delta; |
|
}
|
|
|