tcp: add tcp_conn_request
Create tcp_conn_request and remove most of the code from tcp_v4_conn_request and tcp_v6_conn_request. Signed-off-by: Octavian Purdila <octavian.purdila@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Octavian Purdila
committed by
David S. Miller
David S. Miller
parent
695da14eb0
commit
1fb6f159fd
@@ -1282,137 +1282,13 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
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int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
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{
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struct tcp_options_received tmp_opt;
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struct request_sock *req;
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struct tcp_sock *tp = tcp_sk(sk);
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struct dst_entry *dst = NULL;
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__be32 saddr = ip_hdr(skb)->saddr;
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__u32 isn = TCP_SKB_CB(skb)->when;
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bool want_cookie = false, fastopen;
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struct flowi4 fl4;
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struct tcp_fastopen_cookie foc = { .len = -1 };
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const struct tcp_request_sock_ops *af_ops;
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int err;
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/* Never answer to SYNs send to broadcast or multicast */
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if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
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goto drop;
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/* TW buckets are converted to open requests without
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* limitations, they conserve resources and peer is
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* evidently real one.
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*/
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if ((sysctl_tcp_syncookies == 2 ||
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inet_csk_reqsk_queue_is_full(sk)) && !isn) {
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want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
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if (!want_cookie)
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goto drop;
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}
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return tcp_conn_request(&tcp_request_sock_ops,
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&tcp_request_sock_ipv4_ops, sk, skb);
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/* Accept backlog is full. If we have already queued enough
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* of warm entries in syn queue, drop request. It is better than
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* clogging syn queue with openreqs with exponentially increasing
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* timeout.
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*/
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if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) {
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NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
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goto drop;
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}
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req = inet_reqsk_alloc(&tcp_request_sock_ops);
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if (!req)
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goto drop;
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af_ops = tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
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tcp_clear_options(&tmp_opt);
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tmp_opt.mss_clamp = af_ops->mss_clamp;
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tmp_opt.user_mss = tp->rx_opt.user_mss;
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tcp_parse_options(skb, &tmp_opt, 0, want_cookie ? NULL : &foc);
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if (want_cookie && !tmp_opt.saw_tstamp)
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tcp_clear_options(&tmp_opt);
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tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
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tcp_openreq_init(req, &tmp_opt, skb, sk);
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af_ops->init_req(req, sk, skb);
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if (security_inet_conn_request(sk, skb, req))
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goto drop_and_free;
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if (!want_cookie || tmp_opt.tstamp_ok)
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TCP_ECN_create_request(req, skb, sock_net(sk));
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if (want_cookie) {
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isn = cookie_init_sequence(af_ops, sk, skb, &req->mss);
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req->cookie_ts = tmp_opt.tstamp_ok;
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} else if (!isn) {
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/* VJ's idea. We save last timestamp seen
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* from the destination in peer table, when entering
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* state TIME-WAIT, and check against it before
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* accepting new connection request.
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*
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* If "isn" is not zero, this request hit alive
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* timewait bucket, so that all the necessary checks
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* are made in the function processing timewait state.
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*/
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if (tmp_opt.saw_tstamp && tcp_death_row.sysctl_tw_recycle) {
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bool strict;
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dst = af_ops->route_req(sk, (struct flowi *)&fl4, req,
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&strict);
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if (dst && strict &&
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!tcp_peer_is_proven(req, dst, true)) {
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NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
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goto drop_and_release;
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}
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}
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/* Kill the following clause, if you dislike this way. */
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else if (!sysctl_tcp_syncookies &&
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(sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
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(sysctl_max_syn_backlog >> 2)) &&
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!tcp_peer_is_proven(req, dst, false)) {
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/* Without syncookies last quarter of
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* backlog is filled with destinations,
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* proven to be alive.
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* It means that we continue to communicate
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* to destinations, already remembered
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* to the moment of synflood.
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*/
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LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("drop open request from %pI4/%u\n"),
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&saddr, ntohs(tcp_hdr(skb)->source));
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goto drop_and_release;
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}
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isn = af_ops->init_seq(skb);
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}
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if (!dst) {
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dst = af_ops->route_req(sk, (struct flowi *)&fl4, req, NULL);
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if (!dst)
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goto drop_and_free;
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}
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tcp_rsk(req)->snt_isn = isn;
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tcp_openreq_init_rwin(req, sk, dst);
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fastopen = !want_cookie &&
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tcp_try_fastopen(sk, skb, req, &foc, dst);
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err = af_ops->send_synack(sk, dst, NULL, req,
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skb_get_queue_mapping(skb), &foc);
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if (!fastopen) {
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if (err || want_cookie)
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goto drop_and_free;
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tcp_rsk(req)->listener = NULL;
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af_ops->queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
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}
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return 0;
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drop_and_release:
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dst_release(dst);
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drop_and_free:
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reqsk_free(req);
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drop:
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NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
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return 0;
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