#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 {
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);
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;
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 */
OSDN Git Service
