1 // SPDX-License-Identifier: GPL-2.0-or-later
6  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
31 	WARN_ON(sk->sk_send_head);  in dccp_skb_entail()
32 	sk->sk_send_head = skb;  in dccp_skb_entail()
33 	return skb_clone(sk->sk_send_head, gfp_any());  in dccp_skb_entail()
53 					  dccp_packet_hdr_len(dcb->dccpd_type);  in dccp_transmit_skb()
55 		u64 ackno = dp->dccps_gsr;  in dccp_transmit_skb()
60 		dcb->dccpd_seq = ADD48(dp->dccps_gss, 1);  in dccp_transmit_skb()
62 		switch (dcb->dccpd_type) {  in dccp_transmit_skb()
72 			/* Use ISS on the first (non-retransmitted) Request. */  in dccp_transmit_skb()
73 			if (icsk->icsk_retransmits == 0)  in dccp_transmit_skb()
74 				dcb->dccpd_seq = dp->dccps_iss;  in dccp_transmit_skb()
79 			ackno = dcb->dccpd_ack_seq;  in dccp_transmit_skb()
86 			 * through here with skb->sk set.  in dccp_transmit_skb()
88 			WARN_ON(skb->sk);  in dccp_transmit_skb()
95 			return -EPROTO;  in dccp_transmit_skb()
101 		dh->dccph_type	= dcb->dccpd_type;  in dccp_transmit_skb()
102 		dh->dccph_sport	= inet->inet_sport;  in dccp_transmit_skb()
103 		dh->dccph_dport	= inet->inet_dport;  in dccp_transmit_skb()
104 		dh->dccph_doff	= (dccp_header_size + dcb->dccpd_opt_len) / 4;  in dccp_transmit_skb()
105 		dh->dccph_ccval	= dcb->dccpd_ccval;  in dccp_transmit_skb()
106 		dh->dccph_cscov = dp->dccps_pcslen;  in dccp_transmit_skb()
108 		dh->dccph_x	= 1;  in dccp_transmit_skb()
110 		dccp_update_gss(sk, dcb->dccpd_seq);  in dccp_transmit_skb()
111 		dccp_hdr_set_seq(dh, dp->dccps_gss);  in dccp_transmit_skb()
115 		switch (dcb->dccpd_type) {  in dccp_transmit_skb()
117 			dccp_hdr_request(skb)->dccph_req_service =  in dccp_transmit_skb()
118 							dp->dccps_service;  in dccp_transmit_skb()
123 			dp->dccps_awl = dp->dccps_iss;  in dccp_transmit_skb()
126 			dccp_hdr_reset(skb)->dccph_reset_code =  in dccp_transmit_skb()
127 							dcb->dccpd_reset_code;  in dccp_transmit_skb()
131 		icsk->icsk_af_ops->send_check(sk, skb);  in dccp_transmit_skb()
138 		err = icsk->icsk_af_ops->queue_xmit(sk, skb, &inet->cork.fl);  in dccp_transmit_skb()
141 	return -ENOBUFS;  in dccp_transmit_skb()
145  * dccp_determine_ccmps  -  Find out about CCID-specific packet-size limits
148  * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.),
154 	const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid;  in dccp_determine_ccmps()
156 	if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL)  in dccp_determine_ccmps()
158 	return tx_ccid->ccid_ops->ccid_ccmps;  in dccp_determine_ccmps()
169 	cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len +  in dccp_sync_mss()
174 	 * This only considers options which may appear on DCCP-Data packets, as  in dccp_sync_mss()
178 	 *  - 1 byte for Slow Receiver (11.6)  in dccp_sync_mss()
179 	 *  - 6 bytes for Timestamp (13.1)  in dccp_sync_mss()
180 	 *  - 10 bytes for Timestamp Echo (13.3)  in dccp_sync_mss()
181 	 *  - 8 bytes for NDP count (7.7, when activated)  in dccp_sync_mss()
182 	 *  - 6 bytes for Data Checksum (9.3)  in dccp_sync_mss()
183 	 *  - %DCCPAV_MIN_OPTLEN bytes for Ack Vector size (11.4, when enabled)  in dccp_sync_mss()
185 	cur_mps -= roundup(1 + 6 + 10 + dp->dccps_send_ndp_count * 8 + 6 +  in dccp_sync_mss()
186 			   (dp->dccps_hc_rx_ackvec ? DCCPAV_MIN_OPTLEN : 0), 4);  in dccp_sync_mss()
189 	icsk->icsk_pmtu_cookie = pmtu;  in dccp_sync_mss()
190 	dp->dccps_mss_cache = cur_mps;  in dccp_sync_mss()
202 	wq = rcu_dereference(sk->sk_wq);  in dccp_write_space()
204 		wake_up_interruptible(&wq->wait);  in dccp_write_space()
213  * dccp_wait_for_ccid  -  Await CCID send permission
225 	sk->sk_write_pending++;  in dccp_wait_for_ccid()
231 	sk->sk_write_pending--;  in dccp_wait_for_ccid()
234 	if (signal_pending(current) || sk->sk_err)  in dccp_wait_for_ccid()
235 		return -1;  in dccp_wait_for_ccid()
240  * dccp_xmit_packet  -  Send data packet under control of CCID
243  * Transmits next-queued payload and informs CCID to account for the packet.
253 	len = skb->len;  in dccp_xmit_packet()
255 	if (sk->sk_state == DCCP_PARTOPEN) {  in dccp_xmit_packet()
256 		const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD;  in dccp_xmit_packet()
258 		 * See 8.1.5 - Handshake Completion.  in dccp_xmit_packet()
264 		if (!list_empty(&dp->dccps_featneg) && len > cur_mps) {  in dccp_xmit_packet()
267 			dccp_feat_list_purge(&dp->dccps_featneg);  in dccp_xmit_packet()
272 					      inet_csk(sk)->icsk_rto,  in dccp_xmit_packet()
274 		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK;  in dccp_xmit_packet()
276 		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK;  in dccp_xmit_packet()
278 		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATA;  in dccp_xmit_packet()
289 	ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, len);  in dccp_xmit_packet()
292 	 * If the CCID needs to transfer additional header options out-of-band  in dccp_xmit_packet()
293 	 * (e.g. Ack Vectors or feature-negotiation options), it activates this  in dccp_xmit_packet()
297 	if (dp->dccps_sync_scheduled)  in dccp_xmit_packet()
298 		dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);  in dccp_xmit_packet()
302  * dccp_flush_write_queue  -  Drain queue at end of connection
308  * HC-sender CCID a grace period of up to @time_budget jiffies. If this function
309  * returns with a non-empty write queue, it will be purged later.
317 	while (*time_budget > 0 && (skb = skb_peek(&sk->sk_write_queue))) {  in dccp_flush_write_queue()
318 		rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);  in dccp_flush_write_queue()
336 			*time_budget -= (delay - rc);  in dccp_flush_write_queue()
343 			skb_dequeue(&sk->sk_write_queue);  in dccp_flush_write_queue()
356 		int rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);  in dccp_write_xmit()
362 			sk_reset_timer(sk, &dp->dccps_xmit_timer,  in dccp_write_xmit()
376  * dccp_retransmit_skb  -  Retransmit Request, Close, or CloseReq packets
380  * - Request  in client-REQUEST  state (sec. 8.1.1),
381  * - CloseReq in server-CLOSEREQ state (sec. 8.3),
382  * - Close    in   node-CLOSING  state (sec. 8.3),
383  * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()).
384  * This function expects sk->sk_send_head to contain the original skb.
388 	WARN_ON(sk->sk_send_head == NULL);  in dccp_retransmit_skb()
390 	if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)  in dccp_retransmit_skb()
391 		return -EHOSTUNREACH; /* Routing failure or similar. */  in dccp_retransmit_skb()
394 	inet_csk(sk)->icsk_retransmits++;  in dccp_retransmit_skb()
396 	return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC));  in dccp_retransmit_skb()
410 	 * sock_wmalloc() will atomically change sk->sk_wmem_alloc,  in dccp_make_response()
423 	if (inet_rsk(req)->acked)	/* increase GSS upon retransmission */  in dccp_make_response()
424 		dccp_inc_seqno(&dreq->dreq_gss);  in dccp_make_response()
425 	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;  in dccp_make_response()
426 	DCCP_SKB_CB(skb)->dccpd_seq  = dreq->dreq_gss;  in dccp_make_response()
438 	dh->dccph_sport	= htons(inet_rsk(req)->ir_num);  in dccp_make_response()
439 	dh->dccph_dport	= inet_rsk(req)->ir_rmt_port;  in dccp_make_response()
440 	dh->dccph_doff	= (dccp_header_size +  in dccp_make_response()
441 			   DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;  in dccp_make_response()
442 	dh->dccph_type	= DCCP_PKT_RESPONSE;  in dccp_make_response()
443 	dh->dccph_x	= 1;  in dccp_make_response()
444 	dccp_hdr_set_seq(dh, dreq->dreq_gss);  in dccp_make_response()
445 	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_gsr);  in dccp_make_response()
446 	dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;  in dccp_make_response()
451 	inet_rsk(req)->acked = 1;  in dccp_make_response()
472 	skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);  in dccp_ctl_make_reset()
476 	skb_reserve(skb, sk->sk_prot->max_header);  in dccp_ctl_make_reset()
480 	dh->dccph_type	= DCCP_PKT_RESET;  in dccp_ctl_make_reset()
481 	dh->dccph_sport	= rxdh->dccph_dport;  in dccp_ctl_make_reset()
482 	dh->dccph_dport	= rxdh->dccph_sport;  in dccp_ctl_make_reset()
483 	dh->dccph_doff	= dccp_hdr_reset_len / 4;  in dccp_ctl_make_reset()
484 	dh->dccph_x	= 1;  in dccp_ctl_make_reset()
487 	dhr->dccph_reset_code = dcb->dccpd_reset_code;  in dccp_ctl_make_reset()
489 	switch (dcb->dccpd_reset_code) {  in dccp_ctl_make_reset()
491 		dhr->dccph_reset_data[0] = rxdh->dccph_type;  in dccp_ctl_make_reset()
495 		memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3);  in dccp_ctl_make_reset()
503 	if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)  in dccp_ctl_make_reset()
504 		dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1));  in dccp_ctl_make_reset()
505 	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq);  in dccp_ctl_make_reset()
521 	int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk);  in dccp_send_reset()
526 	skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC);  in dccp_send_reset()
528 		return -ENOBUFS;  in dccp_send_reset()
531 	skb_reserve(skb, sk->sk_prot->max_header);  in dccp_send_reset()
532 	DCCP_SKB_CB(skb)->dccpd_type	   = DCCP_PKT_RESET;  in dccp_send_reset()
533 	DCCP_SKB_CB(skb)->dccpd_reset_code = code;  in dccp_send_reset()
548 	sk->sk_err = 0;  in dccp_connect()
555 		return -EPROTO;  in dccp_connect()
558 	dp->dccps_gar = dp->dccps_iss;  in dccp_connect()
560 	skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);  in dccp_connect()
562 		return -ENOBUFS;  in dccp_connect()
565 	skb_reserve(skb, sk->sk_prot->max_header);  in dccp_connect()
567 	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;  in dccp_connect()
573 	icsk->icsk_retransmits = 0;  in dccp_connect()
575 				  icsk->icsk_rto, DCCP_RTO_MAX);  in dccp_connect()
584 	if (sk->sk_state != DCCP_CLOSED) {  in dccp_send_ack()
585 		struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,  in dccp_send_ack()
590 			inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;  in dccp_send_ack()
598 		skb_reserve(skb, sk->sk_prot->max_header);  in dccp_send_ack()
599 		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;  in dccp_send_ack()
607 /* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */
612 	 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
619 	if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
625 		if (icsk->icsk_ack.blocked) {
630 		if (!time_before(timeout, icsk->icsk_ack.timeout))
631 			timeout = icsk->icsk_ack.timeout;
633 	icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
634 	icsk->icsk_ack.timeout = timeout;
635 	sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
647 	struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);  in dccp_send_sync()
656 	skb_reserve(skb, sk->sk_prot->max_header);  in dccp_send_sync()
657 	DCCP_SKB_CB(skb)->dccpd_type = pkt_type;  in dccp_send_sync()
658 	DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno;  in dccp_send_sync()
661 	 * Clear the flag in case the Sync was scheduled for out-of-band data,  in dccp_send_sync()
664 	dccp_sk(sk)->dccps_sync_scheduled = 0;  in dccp_send_sync()
682 	skb = alloc_skb(sk->sk_prot->max_header, prio);  in dccp_send_close()
687 	skb_reserve(skb, sk->sk_prot->max_header);  in dccp_send_close()
688 	if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait)  in dccp_send_close()
689 		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ;  in dccp_send_close()
691 		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE;  in dccp_send_close()
696 		 * Retransmission timer for active-close: RFC 4340, 8.3 requires  in dccp_send_close()