diff options
| -rw-r--r-- | include/net/tcp.h | 3 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 148 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 128 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 120 |
4 files changed, 155 insertions, 244 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index cec6e2cf0610..0d5389aecf18 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1574,6 +1574,9 @@ void tcp4_proc_exit(void); #endif int tcp_rtx_synack(struct sock *sk, struct request_sock *req); +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); /* TCP af-specific functions */ struct tcp_sock_af_ops { 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); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 845c39de97ab..5dfebd2f2e38 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1282,137 +1282,13 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { int tcp_v4_conn_request(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; - __be32 saddr = ip_hdr(skb)->saddr; - __u32 isn = TCP_SKB_CB(skb)->when; - bool want_cookie = false, fastopen; - struct flowi4 fl4; - struct tcp_fastopen_cookie foc = { .len = -1 }; - const struct tcp_request_sock_ops *af_ops; - int err; - /* Never answer to SYNs send to broadcast or multicast */ if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) goto drop; - /* 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, "TCP"); - 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(&tcp_request_sock_ops); - if (!req) - goto drop; - - af_ops = tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_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; + return tcp_conn_request(&tcp_request_sock_ops, + &tcp_request_sock_ipv4_ops, sk, skb); - 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, (struct flowi *)&fl4, 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. - */ - LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("drop open request from %pI4/%u\n"), - &saddr, ntohs(tcp_hdr(skb)->source)); - goto drop_and_release; - } - - isn = af_ops->init_seq(skb); - } - if (!dst) { - dst = af_ops->route_req(sk, (struct flowi *)&fl4, 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, NULL, 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; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 8232bc7423c6..bc24ee21339a 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1008,133 +1008,17 @@ static struct sock *tcp_v6_hnd_req(struct sock *sk, struct sk_buff *skb) return sk; } -/* FIXME: this is substantially similar to the ipv4 code. - * Can some kind of merge be done? -- erics - */ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) { - struct tcp_options_received tmp_opt; - struct request_sock *req; - struct inet_request_sock *ireq; - struct tcp_sock *tp = tcp_sk(sk); - __u32 isn = TCP_SKB_CB(skb)->when; - struct dst_entry *dst = NULL; - struct tcp_fastopen_cookie foc = { .len = -1 }; - bool want_cookie = false, fastopen; - struct flowi6 fl6; - const struct tcp_request_sock_ops *af_ops; - int err; - if (skb->protocol == htons(ETH_P_IP)) return tcp_v4_conn_request(sk, skb); if (!ipv6_unicast_destination(skb)) goto drop; - if ((sysctl_tcp_syncookies == 2 || - inet_csk_reqsk_queue_is_full(sk)) && !isn) { - want_cookie = tcp_syn_flood_action(sk, skb, "TCPv6"); - if (!want_cookie) - goto drop; - } + return tcp_conn_request(&tcp6_request_sock_ops, + &tcp_request_sock_ipv6_ops, sk, skb); - 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(&tcp6_request_sock_ops); - if (req == NULL) - goto drop; - - af_ops = tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_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); - - ireq = inet_rsk(req); - af_ops->init_req(req, sk, skb); - - if (security_inet_conn_request(sk, skb, req)) - goto drop_and_release; - - 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) { - dst = af_ops->route_req(sk, (struct flowi *)&fl6, req, - NULL); - if (dst && !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. - */ - LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n", - &ireq->ir_v6_rmt_addr, ntohs(tcp_hdr(skb)->source)); - goto drop_and_release; - } - - isn = af_ops->init_seq(skb); - } - - if (!dst) { - dst = af_ops->route_req(sk, (struct flowi *)&fl6, 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, (struct flowi *)&fl6, 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; /* don't send reset */ |