diff options
author | Octavian Purdila <octavian.purdila@intel.com> | 2014-06-25 17:10:02 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2014-06-27 15:53:37 -0700 |
commit | 1fb6f159fd21c640a28eb65fbd62ce8c9f6a777e (patch) | |
tree | b7ba1708058d6c13ee686da1fce92a7d71b84c0f /net/ipv4/tcp_input.c | |
parent | 695da14eb0af21129187ed3810e329b21262e45f (diff) | |
download | linux-1fb6f159fd21c640a28eb65fbd62ce8c9f6a777e.tar.bz2 |
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>
Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r-- | net/ipv4/tcp_input.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index b5c23756965a..97e48d60c4e8 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5877,3 +5877,151 @@ discard: return 0; } EXPORT_SYMBOL(tcp_rcv_state_process); + +static inline void pr_drop_req(struct request_sock *req, __u16 port, int family) +{ + struct inet_request_sock *ireq = inet_rsk(req); + + if (family == AF_INET) + LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("drop open request from %pI4/%u\n"), + &ireq->ir_rmt_addr, port); + else + LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("drop open request from %pI6/%u\n"), + &ireq->ir_v6_rmt_addr, port); +} + +int tcp_conn_request(struct request_sock_ops *rsk_ops, + const struct tcp_request_sock_ops *af_ops, + struct sock *sk, struct sk_buff *skb) +{ + struct tcp_options_received tmp_opt; + struct request_sock *req; + struct tcp_sock *tp = tcp_sk(sk); + struct dst_entry *dst = NULL; + __u32 isn = TCP_SKB_CB(skb)->when; + bool want_cookie = false, fastopen; + struct flowi fl; + struct tcp_fastopen_cookie foc = { .len = -1 }; + int err; + + + /* TW buckets are converted to open requests without + * limitations, they conserve resources and peer is + * evidently real one. + */ + if ((sysctl_tcp_syncookies == 2 || + inet_csk_reqsk_queue_is_full(sk)) && !isn) { + want_cookie = tcp_syn_flood_action(sk, skb, rsk_ops->slab_name); + if (!want_cookie) + goto drop; + } + + + /* Accept backlog is full. If we have already queued enough + * of warm entries in syn queue, drop request. It is better than + * clogging syn queue with openreqs with exponentially increasing + * timeout. + */ + if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); + goto drop; + } + + req = inet_reqsk_alloc(rsk_ops); + if (!req) + goto drop; + + tcp_rsk(req)->af_specific = af_ops; + + tcp_clear_options(&tmp_opt); + tmp_opt.mss_clamp = af_ops->mss_clamp; + tmp_opt.user_mss = tp->rx_opt.user_mss; + tcp_parse_options(skb, &tmp_opt, 0, want_cookie ? NULL : &foc); + + if (want_cookie && !tmp_opt.saw_tstamp) + tcp_clear_options(&tmp_opt); + + tmp_opt.tstamp_ok = tmp_opt.saw_tstamp; + tcp_openreq_init(req, &tmp_opt, skb, sk); + + af_ops->init_req(req, sk, skb); + + if (security_inet_conn_request(sk, skb, req)) + goto drop_and_free; + + if (!want_cookie || tmp_opt.tstamp_ok) + TCP_ECN_create_request(req, skb, sock_net(sk)); + + if (want_cookie) { + isn = cookie_init_sequence(af_ops, sk, skb, &req->mss); + req->cookie_ts = tmp_opt.tstamp_ok; + } else if (!isn) { + /* VJ's idea. We save last timestamp seen + * from the destination in peer table, when entering + * state TIME-WAIT, and check against it before + * accepting new connection request. + * + * If "isn" is not zero, this request hit alive + * timewait bucket, so that all the necessary checks + * are made in the function processing timewait state. + */ + if (tmp_opt.saw_tstamp && tcp_death_row.sysctl_tw_recycle) { + bool strict; + + dst = af_ops->route_req(sk, &fl, req, &strict); + if (dst && strict && + !tcp_peer_is_proven(req, dst, true)) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED); + goto drop_and_release; + } + } + /* Kill the following clause, if you dislike this way. */ + else if (!sysctl_tcp_syncookies && + (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) < + (sysctl_max_syn_backlog >> 2)) && + !tcp_peer_is_proven(req, dst, false)) { + /* Without syncookies last quarter of + * backlog is filled with destinations, + * proven to be alive. + * It means that we continue to communicate + * to destinations, already remembered + * to the moment of synflood. + */ + pr_drop_req(req, ntohs(tcp_hdr(skb)->source), + rsk_ops->family); + goto drop_and_release; + } + + isn = af_ops->init_seq(skb); + } + if (!dst) { + dst = af_ops->route_req(sk, &fl, req, NULL); + if (!dst) + goto drop_and_free; + } + + tcp_rsk(req)->snt_isn = isn; + tcp_openreq_init_rwin(req, sk, dst); + fastopen = !want_cookie && + tcp_try_fastopen(sk, skb, req, &foc, dst); + err = af_ops->send_synack(sk, dst, &fl, req, + skb_get_queue_mapping(skb), &foc); + if (!fastopen) { + if (err || want_cookie) + goto drop_and_free; + + tcp_rsk(req)->listener = NULL; + af_ops->queue_hash_add(sk, req, TCP_TIMEOUT_INIT); + } + + return 0; + +drop_and_release: + dst_release(dst); +drop_and_free: + reqsk_free(req); +drop: + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); + return 0; +} +EXPORT_SYMBOL(tcp_conn_request); |