Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5b7ed089 authored by Yuchung Cheng's avatar Yuchung Cheng Committed by David S. Miller
Browse files

tcp: move fastopen functions to tcp_fastopen.c 



Move common TFO functions that will be used by both v4 and v6
to tcp_fastopen.c. Create a helper tcp_fastopen_queue_check().

Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarDaniel Lee <longinus00@gmail.com>
Signed-off-by: default avatarJerry Chu <hkchu@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4b9734e5

include/net/tcp.h

+8 −2
Original line number Diff line number Diff line
@@ -1329,8 +1329,14 @@ void tcp_free_fastopen_req(struct tcp_sock *tp); 


extern struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;

int tcp_fastopen_reset_cipher(void *key, unsigned int len);

void tcp_fastopen_cookie_gen(__be32 src, __be32 dst,

			     struct tcp_fastopen_cookie *foc);

int tcp_fastopen_create_child(struct sock *sk,

			      struct sk_buff *skb,

			      struct sk_buff *skb_synack,

			      struct request_sock *req);

bool tcp_fastopen_check(struct sock *sk, struct sk_buff *skb,

			struct request_sock *req,

			struct tcp_fastopen_cookie *foc,

			struct tcp_fastopen_cookie *valid_foc);

void tcp_fastopen_init_key_once(bool publish);

#define TCP_FASTOPEN_KEY_LENGTH 16

net/ipv4/tcp_fastopen.c

+190 −0
Original line number Diff line number Diff line
@@ -94,3 +94,193 @@ void tcp_fastopen_cookie_gen(__be32 src, __be32 dst, 
	}

	rcu_read_unlock();

}



int tcp_fastopen_create_child(struct sock *sk,

			      struct sk_buff *skb,

			      struct sk_buff *skb_synack,

			      struct request_sock *req)

{

	struct tcp_sock *tp = tcp_sk(sk);

	struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;

	const struct inet_request_sock *ireq = inet_rsk(req);

	struct sock *child;

	int err;



	req->num_retrans = 0;

	req->num_timeout = 0;

	req->sk = NULL;



	child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);

	if (child == NULL) {

		NET_INC_STATS_BH(sock_net(sk),

				 LINUX_MIB_TCPFASTOPENPASSIVEFAIL);

		kfree_skb(skb_synack);

		return -1;

	}

	err = ip_build_and_send_pkt(skb_synack, sk, ireq->ir_loc_addr,

				    ireq->ir_rmt_addr, ireq->opt);

	err = net_xmit_eval(err);

	if (!err)

		tcp_rsk(req)->snt_synack = tcp_time_stamp;

	/* XXX (TFO) - is it ok to ignore error and continue? */



	spin_lock(&queue->fastopenq->lock);

	queue->fastopenq->qlen++;

	spin_unlock(&queue->fastopenq->lock);



	/* Initialize the child socket. Have to fix some values to take

	 * into account the child is a Fast Open socket and is created

	 * only out of the bits carried in the SYN packet.

	 */

	tp = tcp_sk(child);



	tp->fastopen_rsk = req;

	/* Do a hold on the listner sk so that if the listener is being

	 * closed, the child that has been accepted can live on and still

	 * access listen_lock.

	 */

	sock_hold(sk);

	tcp_rsk(req)->listener = sk;



	/* RFC1323: The window in SYN & SYN/ACK segments is never

	 * scaled. So correct it appropriately.

	 */

	tp->snd_wnd = ntohs(tcp_hdr(skb)->window);



	/* Activate the retrans timer so that SYNACK can be retransmitted.

	 * The request socket is not added to the SYN table of the parent

	 * because it's been added to the accept queue directly.

	 */

	inet_csk_reset_xmit_timer(child, ICSK_TIME_RETRANS,

				  TCP_TIMEOUT_INIT, TCP_RTO_MAX);



	/* Add the child socket directly into the accept queue */

	inet_csk_reqsk_queue_add(sk, req, child);



	/* Now finish processing the fastopen child socket. */

	inet_csk(child)->icsk_af_ops->rebuild_header(child);

	tcp_init_congestion_control(child);

	tcp_mtup_init(child);

	tcp_init_metrics(child);

	tcp_init_buffer_space(child);



	/* Queue the data carried in the SYN packet. We need to first

	 * bump skb's refcnt because the caller will attempt to free it.

	 *

	 * XXX (TFO) - we honor a zero-payload TFO request for now.

	 * (Any reason not to?)

	 */

	if (TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq + 1) {

		/* Don't queue the skb if there is no payload in SYN.

		 * XXX (TFO) - How about SYN+FIN?

		 */

		tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;

	} else {

		skb = skb_get(skb);

		skb_dst_drop(skb);

		__skb_pull(skb, tcp_hdr(skb)->doff * 4);

		skb_set_owner_r(skb, child);

		__skb_queue_tail(&child->sk_receive_queue, skb);

		tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;

		tp->syn_data_acked = 1;

	}

	sk->sk_data_ready(sk);

	bh_unlock_sock(child);

	sock_put(child);

	WARN_ON(req->sk == NULL);

	return 0;

}

EXPORT_SYMBOL(tcp_fastopen_create_child);



static bool tcp_fastopen_queue_check(struct sock *sk)

{

	struct fastopen_queue *fastopenq;



	/* Make sure the listener has enabled fastopen, and we don't

	 * exceed the max # of pending TFO requests allowed before trying

	 * to validating the cookie in order to avoid burning CPU cycles

	 * unnecessarily.

	 *

	 * XXX (TFO) - The implication of checking the max_qlen before

	 * processing a cookie request is that clients can't differentiate

	 * between qlen overflow causing Fast Open to be disabled

	 * temporarily vs a server not supporting Fast Open at all.

	 */

	fastopenq = inet_csk(sk)->icsk_accept_queue.fastopenq;

	if (fastopenq == NULL || fastopenq->max_qlen == 0)

		return false;



	if (fastopenq->qlen >= fastopenq->max_qlen) {

		struct request_sock *req1;

		spin_lock(&fastopenq->lock);

		req1 = fastopenq->rskq_rst_head;

		if ((req1 == NULL) || time_after(req1->expires, jiffies)) {

			spin_unlock(&fastopenq->lock);

			NET_INC_STATS_BH(sock_net(sk),

					 LINUX_MIB_TCPFASTOPENLISTENOVERFLOW);

			return false;

		}

		fastopenq->rskq_rst_head = req1->dl_next;

		fastopenq->qlen--;

		spin_unlock(&fastopenq->lock);

		reqsk_free(req1);

	}

	return true;

}



bool tcp_fastopen_check(struct sock *sk, struct sk_buff *skb,

			struct request_sock *req,

			struct tcp_fastopen_cookie *foc,

			struct tcp_fastopen_cookie *valid_foc)

{

	bool skip_cookie = false;



	if (likely(!fastopen_cookie_present(foc))) {

		/* See include/net/tcp.h for the meaning of these knobs */

		if ((sysctl_tcp_fastopen & TFO_SERVER_ALWAYS) ||

		    ((sysctl_tcp_fastopen & TFO_SERVER_COOKIE_NOT_REQD) &&

		    (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq + 1)))

			skip_cookie = true; /* no cookie to validate */

		else

			return false;

	}

	/* A FO option is present; bump the counter. */

	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVE);



	if ((sysctl_tcp_fastopen & TFO_SERVER_ENABLE) == 0 ||

	    !tcp_fastopen_queue_check(sk))

		return false;



	if (skip_cookie) {

		tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->end_seq;

		return true;

	}



	if (foc->len == TCP_FASTOPEN_COOKIE_SIZE) {

		if ((sysctl_tcp_fastopen & TFO_SERVER_COOKIE_NOT_CHKED) == 0) {

			tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr,

						ip_hdr(skb)->daddr, valid_foc);

			if ((valid_foc->len != TCP_FASTOPEN_COOKIE_SIZE) ||

			    memcmp(&foc->val[0], &valid_foc->val[0],

			    TCP_FASTOPEN_COOKIE_SIZE) != 0)

				return false;

			valid_foc->len = -1;

		}

		/* Acknowledge the data received from the peer. */

		tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->end_seq;

		return true;

	} else if (foc->len == 0) { /* Client requesting a cookie */

		tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr,

					ip_hdr(skb)->daddr, valid_foc);

		NET_INC_STATS_BH(sock_net(sk),

		    LINUX_MIB_TCPFASTOPENCOOKIEREQD);

	} else {

		/* Client sent a cookie with wrong size. Treat it

		 * the same as invalid and return a valid one.

		 */

		tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr,

					ip_hdr(skb)->daddr, valid_foc);

	}

	return false;

}

EXPORT_SYMBOL(tcp_fastopen_check);

net/ipv4/tcp_ipv4.c

+2 −183
Original line number Diff line number Diff line
@@ -1260,187 +1260,6 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { 
};

#endif



static bool tcp_fastopen_check(struct sock *sk, struct sk_buff *skb,

			       struct request_sock *req,

			       struct tcp_fastopen_cookie *foc,

			       struct tcp_fastopen_cookie *valid_foc)

{

	bool skip_cookie = false;

	struct fastopen_queue *fastopenq;



	if (likely(!fastopen_cookie_present(foc))) {

		/* See include/net/tcp.h for the meaning of these knobs */

		if ((sysctl_tcp_fastopen & TFO_SERVER_ALWAYS) ||

		    ((sysctl_tcp_fastopen & TFO_SERVER_COOKIE_NOT_REQD) &&

		    (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq + 1)))

			skip_cookie = true; /* no cookie to validate */

		else

			return false;

	}

	fastopenq = inet_csk(sk)->icsk_accept_queue.fastopenq;

	/* A FO option is present; bump the counter. */

	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVE);



	/* Make sure the listener has enabled fastopen, and we don't

	 * exceed the max # of pending TFO requests allowed before trying

	 * to validating the cookie in order to avoid burning CPU cycles

	 * unnecessarily.

	 *

	 * XXX (TFO) - The implication of checking the max_qlen before

	 * processing a cookie request is that clients can't differentiate

	 * between qlen overflow causing Fast Open to be disabled

	 * temporarily vs a server not supporting Fast Open at all.

	 */

	if ((sysctl_tcp_fastopen & TFO_SERVER_ENABLE) == 0 ||

	    fastopenq == NULL || fastopenq->max_qlen == 0)

		return false;



	if (fastopenq->qlen >= fastopenq->max_qlen) {

		struct request_sock *req1;

		spin_lock(&fastopenq->lock);

		req1 = fastopenq->rskq_rst_head;

		if ((req1 == NULL) || time_after(req1->expires, jiffies)) {

			spin_unlock(&fastopenq->lock);

			NET_INC_STATS_BH(sock_net(sk),

			    LINUX_MIB_TCPFASTOPENLISTENOVERFLOW);

			/* Avoid bumping LINUX_MIB_TCPFASTOPENPASSIVEFAIL*/

			foc->len = -1;

			return false;

		}

		fastopenq->rskq_rst_head = req1->dl_next;

		fastopenq->qlen--;

		spin_unlock(&fastopenq->lock);

		reqsk_free(req1);

	}

	if (skip_cookie) {

		tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->end_seq;

		return true;

	}



	if (foc->len == TCP_FASTOPEN_COOKIE_SIZE) {

		if ((sysctl_tcp_fastopen & TFO_SERVER_COOKIE_NOT_CHKED) == 0) {

			tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr,

						ip_hdr(skb)->daddr, valid_foc);

			if ((valid_foc->len != TCP_FASTOPEN_COOKIE_SIZE) ||

			    memcmp(&foc->val[0], &valid_foc->val[0],

			    TCP_FASTOPEN_COOKIE_SIZE) != 0)

				return false;

			valid_foc->len = -1;

		}

		/* Acknowledge the data received from the peer. */

		tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->end_seq;

		return true;

	} else if (foc->len == 0) { /* Client requesting a cookie */

		tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr,

					ip_hdr(skb)->daddr, valid_foc);

		NET_INC_STATS_BH(sock_net(sk),

		    LINUX_MIB_TCPFASTOPENCOOKIEREQD);

	} else {

		/* Client sent a cookie with wrong size. Treat it

		 * the same as invalid and return a valid one.

		 */

		tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr,

					ip_hdr(skb)->daddr, valid_foc);

	}

	return false;

}



static int tcp_v4_conn_req_fastopen(struct sock *sk,

				    struct sk_buff *skb,

				    struct sk_buff *skb_synack,

				    struct request_sock *req)

{

	struct tcp_sock *tp = tcp_sk(sk);

	struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;

	const struct inet_request_sock *ireq = inet_rsk(req);

	struct sock *child;

	int err;



	req->num_retrans = 0;

	req->num_timeout = 0;

	req->sk = NULL;



	child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);

	if (child == NULL) {

		NET_INC_STATS_BH(sock_net(sk),

				 LINUX_MIB_TCPFASTOPENPASSIVEFAIL);

		kfree_skb(skb_synack);

		return -1;

	}

	err = ip_build_and_send_pkt(skb_synack, sk, ireq->ir_loc_addr,

				    ireq->ir_rmt_addr, ireq->opt);

	err = net_xmit_eval(err);

	if (!err)

		tcp_rsk(req)->snt_synack = tcp_time_stamp;

	/* XXX (TFO) - is it ok to ignore error and continue? */



	spin_lock(&queue->fastopenq->lock);

	queue->fastopenq->qlen++;

	spin_unlock(&queue->fastopenq->lock);



	/* Initialize the child socket. Have to fix some values to take

	 * into account the child is a Fast Open socket and is created

	 * only out of the bits carried in the SYN packet.

	 */

	tp = tcp_sk(child);



	tp->fastopen_rsk = req;

	/* Do a hold on the listner sk so that if the listener is being

	 * closed, the child that has been accepted can live on and still

	 * access listen_lock.

	 */

	sock_hold(sk);

	tcp_rsk(req)->listener = sk;



	/* RFC1323: The window in SYN & SYN/ACK segments is never

	 * scaled. So correct it appropriately.

	 */

	tp->snd_wnd = ntohs(tcp_hdr(skb)->window);



	/* Activate the retrans timer so that SYNACK can be retransmitted.

	 * The request socket is not added to the SYN table of the parent

	 * because it's been added to the accept queue directly.

	 */

	inet_csk_reset_xmit_timer(child, ICSK_TIME_RETRANS,

	    TCP_TIMEOUT_INIT, TCP_RTO_MAX);



	/* Add the child socket directly into the accept queue */

	inet_csk_reqsk_queue_add(sk, req, child);



	/* Now finish processing the fastopen child socket. */

	inet_csk(child)->icsk_af_ops->rebuild_header(child);

	tcp_init_congestion_control(child);

	tcp_mtup_init(child);

	tcp_init_metrics(child);

	tcp_init_buffer_space(child);



	/* Queue the data carried in the SYN packet. We need to first

	 * bump skb's refcnt because the caller will attempt to free it.

	 *

	 * XXX (TFO) - we honor a zero-payload TFO request for now.

	 * (Any reason not to?)

	 */

	if (TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq + 1) {

		/* Don't queue the skb if there is no payload in SYN.

		 * XXX (TFO) - How about SYN+FIN?

		 */

		tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;

	} else {

		skb = skb_get(skb);

		skb_dst_drop(skb);

		__skb_pull(skb, tcp_hdr(skb)->doff * 4);

		skb_set_owner_r(skb, child);

		__skb_queue_tail(&child->sk_receive_queue, skb);

		tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;

		tp->syn_data_acked = 1;

	}

	sk->sk_data_ready(sk);

	bh_unlock_sock(child);

	sock_put(child);

	WARN_ON(req->sk == NULL);

	return 0;

}



int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)

{

	struct tcp_options_received tmp_opt;
@@ -1599,8 +1418,8 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 
		if (fastopen_cookie_present(&foc) && foc.len != 0)

			NET_INC_STATS_BH(sock_net(sk),

			    LINUX_MIB_TCPFASTOPENPASSIVEFAIL);

	} else if (tcp_v4_conn_req_fastopen(sk, skb, skb_synack, req))

		goto drop_and_free;

	} else if (tcp_fastopen_create_child(sk, skb, skb_synack, req))

		goto drop_and_release;



	return 0;