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: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Daniel Lee <longinus00@gmail.com>
Signed-off-by: Jerry Chu <hkchu@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 183 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index ad166dcc278f..032fcaee164a 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -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;