Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
new file mode 100644
index 0000000..2e92384
--- /dev/null
+++ b/net/mptcp/subflow.c
@@ -0,0 +1,1430 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <crypto/algapi.h>
+#include <crypto/sha.h>
+#include <net/sock.h>
+#include <net/inet_common.h>
+#include <net/inet_hashtables.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+#include <net/ip6_route.h>
+#endif
+#include <net/mptcp.h>
+#include <uapi/linux/mptcp.h>
+#include "protocol.h"
+#include "mib.h"
+
+static void SUBFLOW_REQ_INC_STATS(struct request_sock *req,
+ enum linux_mptcp_mib_field field)
+{
+ MPTCP_INC_STATS(sock_net(req_to_sk(req)), field);
+}
+
+static void subflow_req_destructor(struct request_sock *req)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+
+ pr_debug("subflow_req=%p", subflow_req);
+
+ if (subflow_req->msk)
+ sock_put((struct sock *)subflow_req->msk);
+
+ mptcp_token_destroy_request(req);
+ tcp_request_sock_ops.destructor(req);
+}
+
+static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
+ void *hmac)
+{
+ u8 msg[8];
+
+ put_unaligned_be32(nonce1, &msg[0]);
+ put_unaligned_be32(nonce2, &msg[4]);
+
+ mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
+}
+
+static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk)
+{
+ return mptcp_is_fully_established((void *)msk) &&
+ READ_ONCE(msk->pm.accept_subflow);
+}
+
+/* validate received token and create truncated hmac and nonce for SYN-ACK */
+static struct mptcp_sock *subflow_token_join_request(struct request_sock *req,
+ const struct sk_buff *skb)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ u8 hmac[SHA256_DIGEST_SIZE];
+ struct mptcp_sock *msk;
+ int local_id;
+
+ msk = mptcp_token_get_sock(sock_net(req_to_sk(req)), subflow_req->token);
+ if (!msk) {
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN);
+ return NULL;
+ }
+
+ local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req);
+ if (local_id < 0) {
+ sock_put((struct sock *)msk);
+ return NULL;
+ }
+ subflow_req->local_id = local_id;
+
+ get_random_bytes(&subflow_req->local_nonce, sizeof(u32));
+
+ subflow_generate_hmac(msk->local_key, msk->remote_key,
+ subflow_req->local_nonce,
+ subflow_req->remote_nonce, hmac);
+
+ subflow_req->thmac = get_unaligned_be64(hmac);
+ return msk;
+}
+
+static int __subflow_init_req(struct request_sock *req, const struct sock *sk_listener)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+
+ subflow_req->mp_capable = 0;
+ subflow_req->mp_join = 0;
+ subflow_req->msk = NULL;
+ mptcp_token_init_request(req);
+
+#ifdef CONFIG_TCP_MD5SIG
+ /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
+ * TCP option space.
+ */
+ if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info))
+ return -EINVAL;
+#endif
+
+ return 0;
+}
+
+static void subflow_init_req(struct request_sock *req,
+ const struct sock *sk_listener,
+ struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct mptcp_options_received mp_opt;
+ int ret;
+
+ pr_debug("subflow_req=%p, listener=%p", subflow_req, listener);
+
+ ret = __subflow_init_req(req, sk_listener);
+ if (ret)
+ return;
+
+ mptcp_get_options(skb, &mp_opt);
+
+ if (mp_opt.mp_capable) {
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE);
+
+ if (mp_opt.mp_join)
+ return;
+ } else if (mp_opt.mp_join) {
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX);
+ }
+
+ if (mp_opt.mp_capable && listener->request_mptcp) {
+ int err, retries = 4;
+
+ subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
+again:
+ do {
+ get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key));
+ } while (subflow_req->local_key == 0);
+
+ if (unlikely(req->syncookie)) {
+ mptcp_crypto_key_sha(subflow_req->local_key,
+ &subflow_req->token,
+ &subflow_req->idsn);
+ if (mptcp_token_exists(subflow_req->token)) {
+ if (retries-- > 0)
+ goto again;
+ } else {
+ subflow_req->mp_capable = 1;
+ }
+ return;
+ }
+
+ err = mptcp_token_new_request(req);
+ if (err == 0)
+ subflow_req->mp_capable = 1;
+ else if (retries-- > 0)
+ goto again;
+
+ } else if (mp_opt.mp_join && listener->request_mptcp) {
+ subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
+ subflow_req->mp_join = 1;
+ subflow_req->backup = mp_opt.backup;
+ subflow_req->remote_id = mp_opt.join_id;
+ subflow_req->token = mp_opt.token;
+ subflow_req->remote_nonce = mp_opt.nonce;
+ subflow_req->msk = subflow_token_join_request(req, skb);
+
+ if (unlikely(req->syncookie) && subflow_req->msk) {
+ if (mptcp_can_accept_new_subflow(subflow_req->msk))
+ subflow_init_req_cookie_join_save(subflow_req, skb);
+ }
+
+ pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token,
+ subflow_req->remote_nonce, subflow_req->msk);
+ }
+}
+
+int mptcp_subflow_init_cookie_req(struct request_sock *req,
+ const struct sock *sk_listener,
+ struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct mptcp_options_received mp_opt;
+ int err;
+
+ err = __subflow_init_req(req, sk_listener);
+ if (err)
+ return err;
+
+ mptcp_get_options(skb, &mp_opt);
+
+ if (mp_opt.mp_capable && mp_opt.mp_join)
+ return -EINVAL;
+
+ if (mp_opt.mp_capable && listener->request_mptcp) {
+ if (mp_opt.sndr_key == 0)
+ return -EINVAL;
+
+ subflow_req->local_key = mp_opt.rcvr_key;
+ err = mptcp_token_new_request(req);
+ if (err)
+ return err;
+
+ subflow_req->mp_capable = 1;
+ subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
+ } else if (mp_opt.mp_join && listener->request_mptcp) {
+ if (!mptcp_token_join_cookie_init_state(subflow_req, skb))
+ return -EINVAL;
+
+ if (mptcp_can_accept_new_subflow(subflow_req->msk))
+ subflow_req->mp_join = 1;
+
+ subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req);
+
+static void subflow_v4_init_req(struct request_sock *req,
+ const struct sock *sk_listener,
+ struct sk_buff *skb)
+{
+ tcp_rsk(req)->is_mptcp = 1;
+
+ tcp_request_sock_ipv4_ops.init_req(req, sk_listener, skb);
+
+ subflow_init_req(req, sk_listener, skb);
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static void subflow_v6_init_req(struct request_sock *req,
+ const struct sock *sk_listener,
+ struct sk_buff *skb)
+{
+ tcp_rsk(req)->is_mptcp = 1;
+
+ tcp_request_sock_ipv6_ops.init_req(req, sk_listener, skb);
+
+ subflow_init_req(req, sk_listener, skb);
+}
+#endif
+
+/* validate received truncated hmac and create hmac for third ACK */
+static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow)
+{
+ u8 hmac[SHA256_DIGEST_SIZE];
+ u64 thmac;
+
+ subflow_generate_hmac(subflow->remote_key, subflow->local_key,
+ subflow->remote_nonce, subflow->local_nonce,
+ hmac);
+
+ thmac = get_unaligned_be64(hmac);
+ pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n",
+ subflow, subflow->token,
+ (unsigned long long)thmac,
+ (unsigned long long)subflow->thmac);
+
+ return thmac == subflow->thmac;
+}
+
+void mptcp_subflow_reset(struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct sock *sk = subflow->conn;
+
+ tcp_set_state(ssk, TCP_CLOSE);
+ tcp_send_active_reset(ssk, GFP_ATOMIC);
+ tcp_done(ssk);
+ if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags) &&
+ schedule_work(&mptcp_sk(sk)->work))
+ sock_hold(sk);
+}
+
+static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_options_received mp_opt;
+ struct sock *parent = subflow->conn;
+
+ subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
+
+ if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
+ inet_sk_state_store(parent, TCP_ESTABLISHED);
+ parent->sk_state_change(parent);
+ }
+
+ /* be sure no special action on any packet other than syn-ack */
+ if (subflow->conn_finished)
+ return;
+
+ subflow->rel_write_seq = 1;
+ subflow->conn_finished = 1;
+ subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
+ pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset);
+
+ mptcp_get_options(skb, &mp_opt);
+ if (subflow->request_mptcp) {
+ if (!mp_opt.mp_capable) {
+ MPTCP_INC_STATS(sock_net(sk),
+ MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
+ mptcp_do_fallback(sk);
+ pr_fallback(mptcp_sk(subflow->conn));
+ goto fallback;
+ }
+
+ subflow->mp_capable = 1;
+ subflow->can_ack = 1;
+ subflow->remote_key = mp_opt.sndr_key;
+ pr_debug("subflow=%p, remote_key=%llu", subflow,
+ subflow->remote_key);
+ mptcp_finish_connect(sk);
+ } else if (subflow->request_join) {
+ u8 hmac[SHA256_DIGEST_SIZE];
+
+ if (!mp_opt.mp_join)
+ goto do_reset;
+
+ subflow->thmac = mp_opt.thmac;
+ subflow->remote_nonce = mp_opt.nonce;
+ pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
+ subflow->thmac, subflow->remote_nonce);
+
+ if (!subflow_thmac_valid(subflow)) {
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC);
+ goto do_reset;
+ }
+
+ if (!mptcp_finish_join(sk))
+ goto do_reset;
+
+ subflow_generate_hmac(subflow->local_key, subflow->remote_key,
+ subflow->local_nonce,
+ subflow->remote_nonce,
+ hmac);
+ memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN);
+
+ subflow->mp_join = 1;
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);
+ } else if (mptcp_check_fallback(sk)) {
+fallback:
+ mptcp_rcv_space_init(mptcp_sk(parent), sk);
+ }
+ return;
+
+do_reset:
+ mptcp_subflow_reset(sk);
+}
+
+struct request_sock_ops mptcp_subflow_request_sock_ops;
+EXPORT_SYMBOL_GPL(mptcp_subflow_request_sock_ops);
+static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops;
+
+static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+
+ pr_debug("subflow=%p", subflow);
+
+ /* Never answer to SYNs sent to broadcast or multicast */
+ if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
+ goto drop;
+
+ return tcp_conn_request(&mptcp_subflow_request_sock_ops,
+ &subflow_request_sock_ipv4_ops,
+ sk, skb);
+drop:
+ tcp_listendrop(sk);
+ return 0;
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops;
+static struct inet_connection_sock_af_ops subflow_v6_specific;
+static struct inet_connection_sock_af_ops subflow_v6m_specific;
+
+static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+
+ pr_debug("subflow=%p", subflow);
+
+ if (skb->protocol == htons(ETH_P_IP))
+ return subflow_v4_conn_request(sk, skb);
+
+ if (!ipv6_unicast_destination(skb))
+ goto drop;
+
+ if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) {
+ __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS);
+ return 0;
+ }
+
+ return tcp_conn_request(&mptcp_subflow_request_sock_ops,
+ &subflow_request_sock_ipv6_ops, sk, skb);
+
+drop:
+ tcp_listendrop(sk);
+ return 0; /* don't send reset */
+}
+#endif
+
+/* validate hmac received in third ACK */
+static bool subflow_hmac_valid(const struct request_sock *req,
+ const struct mptcp_options_received *mp_opt)
+{
+ const struct mptcp_subflow_request_sock *subflow_req;
+ u8 hmac[SHA256_DIGEST_SIZE];
+ struct mptcp_sock *msk;
+
+ subflow_req = mptcp_subflow_rsk(req);
+ msk = subflow_req->msk;
+ if (!msk)
+ return false;
+
+ subflow_generate_hmac(msk->remote_key, msk->local_key,
+ subflow_req->remote_nonce,
+ subflow_req->local_nonce, hmac);
+
+ return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN);
+}
+
+static void mptcp_sock_destruct(struct sock *sk)
+{
+ /* if new mptcp socket isn't accepted, it is free'd
+ * from the tcp listener sockets request queue, linked
+ * from req->sk. The tcp socket is released.
+ * This calls the ULP release function which will
+ * also remove the mptcp socket, via
+ * sock_put(ctx->conn).
+ *
+ * Problem is that the mptcp socket will be in
+ * ESTABLISHED state and will not have the SOCK_DEAD flag.
+ * Both result in warnings from inet_sock_destruct.
+ */
+ if ((1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
+ sk->sk_state = TCP_CLOSE;
+ WARN_ON_ONCE(sk->sk_socket);
+ sock_orphan(sk);
+ }
+
+ mptcp_destroy_common(mptcp_sk(sk));
+ inet_sock_destruct(sk);
+}
+
+static void mptcp_force_close(struct sock *sk)
+{
+ inet_sk_state_store(sk, TCP_CLOSE);
+ sk_common_release(sk);
+}
+
+static void subflow_ulp_fallback(struct sock *sk,
+ struct mptcp_subflow_context *old_ctx)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ mptcp_subflow_tcp_fallback(sk, old_ctx);
+ icsk->icsk_ulp_ops = NULL;
+ rcu_assign_pointer(icsk->icsk_ulp_data, NULL);
+ tcp_sk(sk)->is_mptcp = 0;
+}
+
+static void subflow_drop_ctx(struct sock *ssk)
+{
+ struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk);
+
+ if (!ctx)
+ return;
+
+ subflow_ulp_fallback(ssk, ctx);
+ if (ctx->conn)
+ sock_put(ctx->conn);
+
+ kfree_rcu(ctx, rcu);
+}
+
+void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
+ struct mptcp_options_received *mp_opt)
+{
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+
+ subflow->remote_key = mp_opt->sndr_key;
+ subflow->fully_established = 1;
+ subflow->can_ack = 1;
+ WRITE_ONCE(msk->fully_established, true);
+}
+
+static struct sock *subflow_syn_recv_sock(const struct sock *sk,
+ struct sk_buff *skb,
+ struct request_sock *req,
+ struct dst_entry *dst,
+ struct request_sock *req_unhash,
+ bool *own_req)
+{
+ struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);
+ struct mptcp_subflow_request_sock *subflow_req;
+ struct mptcp_options_received mp_opt;
+ bool fallback, fallback_is_fatal;
+ struct sock *new_msk = NULL;
+ struct sock *child;
+
+ pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
+
+ /* After child creation we must look for 'mp_capable' even when options
+ * are not parsed
+ */
+ mp_opt.mp_capable = 0;
+
+ /* hopefully temporary handling for MP_JOIN+syncookie */
+ subflow_req = mptcp_subflow_rsk(req);
+ fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join;
+ fallback = !tcp_rsk(req)->is_mptcp;
+ if (fallback)
+ goto create_child;
+
+ /* if the sk is MP_CAPABLE, we try to fetch the client key */
+ if (subflow_req->mp_capable) {
+ /* we can receive and accept an in-window, out-of-order pkt,
+ * which may not carry the MP_CAPABLE opt even on mptcp enabled
+ * paths: always try to extract the peer key, and fallback
+ * for packets missing it.
+ * Even OoO DSS packets coming legitly after dropped or
+ * reordered MPC will cause fallback, but we don't have other
+ * options.
+ */
+ mptcp_get_options(skb, &mp_opt);
+ if (!mp_opt.mp_capable) {
+ fallback = true;
+ goto create_child;
+ }
+
+ new_msk = mptcp_sk_clone(listener->conn, &mp_opt, req);
+ if (!new_msk)
+ fallback = true;
+ } else if (subflow_req->mp_join) {
+ mptcp_get_options(skb, &mp_opt);
+ if (!mp_opt.mp_join || !subflow_hmac_valid(req, &mp_opt) ||
+ !mptcp_can_accept_new_subflow(subflow_req->msk)) {
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
+ fallback = true;
+ }
+ }
+
+create_child:
+ child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst,
+ req_unhash, own_req);
+
+ if (child && *own_req) {
+ struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child);
+
+ tcp_rsk(req)->drop_req = false;
+
+ /* we need to fallback on ctx allocation failure and on pre-reqs
+ * checking above. In the latter scenario we additionally need
+ * to reset the context to non MPTCP status.
+ */
+ if (!ctx || fallback) {
+ if (fallback_is_fatal)
+ goto dispose_child;
+
+ subflow_drop_ctx(child);
+ goto out;
+ }
+
+ if (ctx->mp_capable) {
+ /* this can't race with mptcp_close(), as the msk is
+ * not yet exposted to user-space
+ */
+ inet_sk_state_store((void *)new_msk, TCP_ESTABLISHED);
+
+ /* new mpc subflow takes ownership of the newly
+ * created mptcp socket
+ */
+ new_msk->sk_destruct = mptcp_sock_destruct;
+ mptcp_pm_new_connection(mptcp_sk(new_msk), 1);
+ mptcp_token_accept(subflow_req, mptcp_sk(new_msk));
+ ctx->conn = new_msk;
+ new_msk = NULL;
+
+ /* with OoO packets we can reach here without ingress
+ * mpc option
+ */
+ if (mp_opt.mp_capable)
+ mptcp_subflow_fully_established(ctx, &mp_opt);
+ } else if (ctx->mp_join) {
+ struct mptcp_sock *owner;
+
+ owner = subflow_req->msk;
+ if (!owner)
+ goto dispose_child;
+
+ /* move the msk reference ownership to the subflow */
+ subflow_req->msk = NULL;
+ ctx->conn = (struct sock *)owner;
+ if (!mptcp_finish_join(child))
+ goto dispose_child;
+
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX);
+ tcp_rsk(req)->drop_req = true;
+ }
+ }
+
+out:
+ /* dispose of the left over mptcp master, if any */
+ if (unlikely(new_msk))
+ mptcp_force_close(new_msk);
+
+ /* check for expected invariant - should never trigger, just help
+ * catching eariler subtle bugs
+ */
+ WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp &&
+ (!mptcp_subflow_ctx(child) ||
+ !mptcp_subflow_ctx(child)->conn));
+ return child;
+
+dispose_child:
+ subflow_drop_ctx(child);
+ tcp_rsk(req)->drop_req = true;
+ inet_csk_prepare_for_destroy_sock(child);
+ tcp_done(child);
+ req->rsk_ops->send_reset(sk, skb);
+
+ /* The last child reference will be released by the caller */
+ return child;
+}
+
+static struct inet_connection_sock_af_ops subflow_specific;
+
+enum mapping_status {
+ MAPPING_OK,
+ MAPPING_INVALID,
+ MAPPING_EMPTY,
+ MAPPING_DATA_FIN,
+ MAPPING_DUMMY
+};
+
+static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq)
+{
+ if ((u32)seq == (u32)old_seq)
+ return old_seq;
+
+ /* Assume map covers data not mapped yet. */
+ return seq | ((old_seq + old_data_len + 1) & GENMASK_ULL(63, 32));
+}
+
+static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
+{
+ pr_debug("Bad mapping: ssn=%d map_seq=%d map_data_len=%d",
+ ssn, subflow->map_subflow_seq, subflow->map_data_len);
+}
+
+static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ unsigned int skb_consumed;
+
+ skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq;
+ if (WARN_ON_ONCE(skb_consumed >= skb->len))
+ return true;
+
+ return skb->len - skb_consumed <= subflow->map_data_len -
+ mptcp_subflow_get_map_offset(subflow);
+}
+
+static bool validate_mapping(struct sock *ssk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset;
+
+ if (unlikely(before(ssn, subflow->map_subflow_seq))) {
+ /* Mapping covers data later in the subflow stream,
+ * currently unsupported.
+ */
+ dbg_bad_map(subflow, ssn);
+ return false;
+ }
+ if (unlikely(!before(ssn, subflow->map_subflow_seq +
+ subflow->map_data_len))) {
+ /* Mapping does covers past subflow data, invalid */
+ dbg_bad_map(subflow, ssn);
+ return false;
+ }
+ return true;
+}
+
+static enum mapping_status get_mapping_status(struct sock *ssk,
+ struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct mptcp_ext *mpext;
+ struct sk_buff *skb;
+ u16 data_len;
+ u64 map_seq;
+
+ skb = skb_peek(&ssk->sk_receive_queue);
+ if (!skb)
+ return MAPPING_EMPTY;
+
+ if (mptcp_check_fallback(ssk))
+ return MAPPING_DUMMY;
+
+ mpext = mptcp_get_ext(skb);
+ if (!mpext || !mpext->use_map) {
+ if (!subflow->map_valid && !skb->len) {
+ /* the TCP stack deliver 0 len FIN pkt to the receive
+ * queue, that is the only 0len pkts ever expected here,
+ * and we can admit no mapping only for 0 len pkts
+ */
+ if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN))
+ WARN_ONCE(1, "0len seq %d:%d flags %x",
+ TCP_SKB_CB(skb)->seq,
+ TCP_SKB_CB(skb)->end_seq,
+ TCP_SKB_CB(skb)->tcp_flags);
+ sk_eat_skb(ssk, skb);
+ return MAPPING_EMPTY;
+ }
+
+ if (!subflow->map_valid)
+ return MAPPING_INVALID;
+
+ goto validate_seq;
+ }
+
+ pr_debug("seq=%llu is64=%d ssn=%u data_len=%u data_fin=%d",
+ mpext->data_seq, mpext->dsn64, mpext->subflow_seq,
+ mpext->data_len, mpext->data_fin);
+
+ data_len = mpext->data_len;
+ if (data_len == 0) {
+ MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
+ return MAPPING_INVALID;
+ }
+
+ if (mpext->data_fin == 1) {
+ if (data_len == 1) {
+ bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq,
+ mpext->dsn64);
+ pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq);
+ if (subflow->map_valid) {
+ /* A DATA_FIN might arrive in a DSS
+ * option before the previous mapping
+ * has been fully consumed. Continue
+ * handling the existing mapping.
+ */
+ skb_ext_del(skb, SKB_EXT_MPTCP);
+ return MAPPING_OK;
+ } else {
+ if (updated && schedule_work(&msk->work))
+ sock_hold((struct sock *)msk);
+
+ return MAPPING_DATA_FIN;
+ }
+ } else {
+ u64 data_fin_seq = mpext->data_seq + data_len - 1;
+
+ /* If mpext->data_seq is a 32-bit value, data_fin_seq
+ * must also be limited to 32 bits.
+ */
+ if (!mpext->dsn64)
+ data_fin_seq &= GENMASK_ULL(31, 0);
+
+ mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64);
+ pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d",
+ data_fin_seq, mpext->dsn64);
+ }
+
+ /* Adjust for DATA_FIN using 1 byte of sequence space */
+ data_len--;
+ }
+
+ if (!mpext->dsn64) {
+ map_seq = expand_seq(subflow->map_seq, subflow->map_data_len,
+ mpext->data_seq);
+ pr_debug("expanded seq=%llu", subflow->map_seq);
+ } else {
+ map_seq = mpext->data_seq;
+ }
+ WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64);
+
+ if (subflow->map_valid) {
+ /* Allow replacing only with an identical map */
+ if (subflow->map_seq == map_seq &&
+ subflow->map_subflow_seq == mpext->subflow_seq &&
+ subflow->map_data_len == data_len) {
+ skb_ext_del(skb, SKB_EXT_MPTCP);
+ return MAPPING_OK;
+ }
+
+ /* If this skb data are fully covered by the current mapping,
+ * the new map would need caching, which is not supported
+ */
+ if (skb_is_fully_mapped(ssk, skb)) {
+ MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSNOMATCH);
+ return MAPPING_INVALID;
+ }
+
+ /* will validate the next map after consuming the current one */
+ return MAPPING_OK;
+ }
+
+ subflow->map_seq = map_seq;
+ subflow->map_subflow_seq = mpext->subflow_seq;
+ subflow->map_data_len = data_len;
+ subflow->map_valid = 1;
+ subflow->mpc_map = mpext->mpc_map;
+ pr_debug("new map seq=%llu subflow_seq=%u data_len=%u",
+ subflow->map_seq, subflow->map_subflow_seq,
+ subflow->map_data_len);
+
+validate_seq:
+ /* we revalidate valid mapping on new skb, because we must ensure
+ * the current skb is completely covered by the available mapping
+ */
+ if (!validate_mapping(ssk, skb))
+ return MAPPING_INVALID;
+
+ skb_ext_del(skb, SKB_EXT_MPTCP);
+ return MAPPING_OK;
+}
+
+static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb,
+ u64 limit)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
+ u32 incr;
+
+ incr = limit >= skb->len ? skb->len + fin : limit;
+
+ pr_debug("discarding=%d len=%d seq=%d", incr, skb->len,
+ subflow->map_subflow_seq);
+ MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DUPDATA);
+ tcp_sk(ssk)->copied_seq += incr;
+ if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq))
+ sk_eat_skb(ssk, skb);
+ if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len)
+ subflow->map_valid = 0;
+ if (incr)
+ tcp_cleanup_rbuf(ssk, incr);
+}
+
+static bool subflow_check_data_avail(struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ enum mapping_status status;
+ struct mptcp_sock *msk;
+ struct sk_buff *skb;
+
+ pr_debug("msk=%p ssk=%p data_avail=%d skb=%p", subflow->conn, ssk,
+ subflow->data_avail, skb_peek(&ssk->sk_receive_queue));
+ if (!skb_peek(&ssk->sk_receive_queue))
+ subflow->data_avail = 0;
+ if (subflow->data_avail)
+ return true;
+
+ msk = mptcp_sk(subflow->conn);
+ for (;;) {
+ u64 ack_seq;
+ u64 old_ack;
+
+ status = get_mapping_status(ssk, msk);
+ pr_debug("msk=%p ssk=%p status=%d", msk, ssk, status);
+ if (status == MAPPING_INVALID) {
+ ssk->sk_err = EBADMSG;
+ goto fatal;
+ }
+ if (status == MAPPING_DUMMY) {
+ __mptcp_do_fallback(msk);
+ skb = skb_peek(&ssk->sk_receive_queue);
+ subflow->map_valid = 1;
+ subflow->map_seq = READ_ONCE(msk->ack_seq);
+ subflow->map_data_len = skb->len;
+ subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq -
+ subflow->ssn_offset;
+ subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
+ return true;
+ }
+
+ if (status != MAPPING_OK)
+ return false;
+
+ skb = skb_peek(&ssk->sk_receive_queue);
+ if (WARN_ON_ONCE(!skb))
+ return false;
+
+ /* if msk lacks the remote key, this subflow must provide an
+ * MP_CAPABLE-based mapping
+ */
+ if (unlikely(!READ_ONCE(msk->can_ack))) {
+ if (!subflow->mpc_map) {
+ ssk->sk_err = EBADMSG;
+ goto fatal;
+ }
+ WRITE_ONCE(msk->remote_key, subflow->remote_key);
+ WRITE_ONCE(msk->ack_seq, subflow->map_seq);
+ WRITE_ONCE(msk->can_ack, true);
+ }
+
+ old_ack = READ_ONCE(msk->ack_seq);
+ ack_seq = mptcp_subflow_get_mapped_dsn(subflow);
+ pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack,
+ ack_seq);
+ if (ack_seq == old_ack) {
+ subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
+ break;
+ } else if (after64(ack_seq, old_ack)) {
+ subflow->data_avail = MPTCP_SUBFLOW_OOO_DATA;
+ break;
+ }
+
+ /* only accept in-sequence mapping. Old values are spurious
+ * retransmission
+ */
+ mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq);
+ }
+ return true;
+
+fatal:
+ /* fatal protocol error, close the socket */
+ /* This barrier is coupled with smp_rmb() in tcp_poll() */
+ smp_wmb();
+ ssk->sk_error_report(ssk);
+ tcp_set_state(ssk, TCP_CLOSE);
+ tcp_send_active_reset(ssk, GFP_ATOMIC);
+ subflow->data_avail = 0;
+ return false;
+}
+
+bool mptcp_subflow_data_available(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+
+ /* check if current mapping is still valid */
+ if (subflow->map_valid &&
+ mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) {
+ subflow->map_valid = 0;
+ subflow->data_avail = 0;
+
+ pr_debug("Done with mapping: seq=%u data_len=%u",
+ subflow->map_subflow_seq,
+ subflow->map_data_len);
+ }
+
+ return subflow_check_data_avail(sk);
+}
+
+/* If ssk has an mptcp parent socket, use the mptcp rcvbuf occupancy,
+ * not the ssk one.
+ *
+ * In mptcp, rwin is about the mptcp-level connection data.
+ *
+ * Data that is still on the ssk rx queue can thus be ignored,
+ * as far as mptcp peer is concerened that data is still inflight.
+ * DSS ACK is updated when skb is moved to the mptcp rx queue.
+ */
+void mptcp_space(const struct sock *ssk, int *space, int *full_space)
+{
+ const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ const struct sock *sk = subflow->conn;
+
+ *space = tcp_space(sk);
+ *full_space = tcp_full_space(sk);
+}
+
+static void subflow_data_ready(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ u16 state = 1 << inet_sk_state_load(sk);
+ struct sock *parent = subflow->conn;
+ struct mptcp_sock *msk;
+
+ msk = mptcp_sk(parent);
+ if (state & TCPF_LISTEN) {
+ /* MPJ subflow are removed from accept queue before reaching here,
+ * avoid stray wakeups
+ */
+ if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue))
+ return;
+
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ parent->sk_data_ready(parent);
+ return;
+ }
+
+ WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable &&
+ !subflow->mp_join && !(state & TCPF_CLOSE));
+
+ if (mptcp_subflow_data_available(sk))
+ mptcp_data_ready(parent, sk);
+}
+
+static void subflow_write_space(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct sock *parent = subflow->conn;
+
+ if (!sk_stream_is_writeable(sk))
+ return;
+
+ if (sk_stream_is_writeable(parent)) {
+ set_bit(MPTCP_SEND_SPACE, &mptcp_sk(parent)->flags);
+ smp_mb__after_atomic();
+ /* set SEND_SPACE before sk_stream_write_space clears NOSPACE */
+ sk_stream_write_space(parent);
+ }
+}
+
+static struct inet_connection_sock_af_ops *
+subflow_default_af_ops(struct sock *sk)
+{
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (sk->sk_family == AF_INET6)
+ return &subflow_v6_specific;
+#endif
+ return &subflow_specific;
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+void mptcpv6_handle_mapped(struct sock *sk, bool mapped)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct inet_connection_sock_af_ops *target;
+
+ target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk);
+
+ pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d",
+ subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped);
+
+ if (likely(icsk->icsk_af_ops == target))
+ return;
+
+ subflow->icsk_af_ops = icsk->icsk_af_ops;
+ icsk->icsk_af_ops = target;
+}
+#endif
+
+static void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
+ struct sockaddr_storage *addr)
+{
+ memset(addr, 0, sizeof(*addr));
+ addr->ss_family = info->family;
+ if (addr->ss_family == AF_INET) {
+ struct sockaddr_in *in_addr = (struct sockaddr_in *)addr;
+
+ in_addr->sin_addr = info->addr;
+ in_addr->sin_port = info->port;
+ }
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (addr->ss_family == AF_INET6) {
+ struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr;
+
+ in6_addr->sin6_addr = info->addr6;
+ in6_addr->sin6_port = info->port;
+ }
+#endif
+}
+
+int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
+ const struct mptcp_addr_info *remote)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_subflow_context *subflow;
+ struct sockaddr_storage addr;
+ int remote_id = remote->id;
+ int local_id = loc->id;
+ struct socket *sf;
+ struct sock *ssk;
+ u32 remote_token;
+ int addrlen;
+ int err;
+
+ if (!mptcp_is_fully_established(sk))
+ return -ENOTCONN;
+
+ err = mptcp_subflow_create_socket(sk, &sf);
+ if (err)
+ return err;
+
+ ssk = sf->sk;
+ subflow = mptcp_subflow_ctx(ssk);
+ do {
+ get_random_bytes(&subflow->local_nonce, sizeof(u32));
+ } while (!subflow->local_nonce);
+
+ if (!local_id) {
+ err = mptcp_pm_get_local_id(msk, (struct sock_common *)ssk);
+ if (err < 0)
+ goto failed;
+
+ local_id = err;
+ }
+
+ subflow->remote_key = msk->remote_key;
+ subflow->local_key = msk->local_key;
+ subflow->token = msk->token;
+ mptcp_info2sockaddr(loc, &addr);
+
+ addrlen = sizeof(struct sockaddr_in);
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (loc->family == AF_INET6)
+ addrlen = sizeof(struct sockaddr_in6);
+#endif
+ ssk->sk_bound_dev_if = loc->ifindex;
+ err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen);
+ if (err)
+ goto failed;
+
+ mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL);
+ pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk,
+ remote_token, local_id, remote_id);
+ subflow->remote_token = remote_token;
+ subflow->local_id = local_id;
+ subflow->remote_id = remote_id;
+ subflow->request_join = 1;
+ subflow->request_bkup = !!(loc->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+ mptcp_info2sockaddr(remote, &addr);
+
+ err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK);
+ if (err && err != -EINPROGRESS)
+ goto failed;
+
+ spin_lock_bh(&msk->join_list_lock);
+ list_add_tail(&subflow->node, &msk->join_list);
+ spin_unlock_bh(&msk->join_list_lock);
+
+ return err;
+
+failed:
+ sock_release(sf);
+ return err;
+}
+
+int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock)
+{
+ struct mptcp_subflow_context *subflow;
+ struct net *net = sock_net(sk);
+ struct socket *sf;
+ int err;
+
+ /* un-accepted server sockets can reach here - on bad configuration
+ * bail early to avoid greater trouble later
+ */
+ if (unlikely(!sk->sk_socket))
+ return -EINVAL;
+
+ err = sock_create_kern(net, sk->sk_family, SOCK_STREAM, IPPROTO_TCP,
+ &sf);
+ if (err)
+ return err;
+
+ lock_sock(sf->sk);
+
+ /* kernel sockets do not by default acquire net ref, but TCP timer
+ * needs it.
+ */
+ sf->sk->sk_net_refcnt = 1;
+ get_net(net);
+#ifdef CONFIG_PROC_FS
+ this_cpu_add(*net->core.sock_inuse, 1);
+#endif
+ err = tcp_set_ulp(sf->sk, "mptcp");
+ release_sock(sf->sk);
+
+ if (err) {
+ sock_release(sf);
+ return err;
+ }
+
+ /* the newly created socket really belongs to the owning MPTCP master
+ * socket, even if for additional subflows the allocation is performed
+ * by a kernel workqueue. Adjust inode references, so that the
+ * procfs/diag interaces really show this one belonging to the correct
+ * user.
+ */
+ SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino;
+ SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid;
+ SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid;
+
+ subflow = mptcp_subflow_ctx(sf->sk);
+ pr_debug("subflow=%p", subflow);
+
+ *new_sock = sf;
+ sock_hold(sk);
+ subflow->conn = sk;
+
+ return 0;
+}
+
+static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk,
+ gfp_t priority)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct mptcp_subflow_context *ctx;
+
+ ctx = kzalloc(sizeof(*ctx), priority);
+ if (!ctx)
+ return NULL;
+
+ rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
+ INIT_LIST_HEAD(&ctx->node);
+
+ pr_debug("subflow=%p", ctx);
+
+ ctx->tcp_sock = sk;
+
+ return ctx;
+}
+
+static void __subflow_state_change(struct sock *sk)
+{
+ struct socket_wq *wq;
+
+ rcu_read_lock();
+ wq = rcu_dereference(sk->sk_wq);
+ if (skwq_has_sleeper(wq))
+ wake_up_interruptible_all(&wq->wait);
+ rcu_read_unlock();
+}
+
+static bool subflow_is_done(const struct sock *sk)
+{
+ return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE;
+}
+
+static void subflow_state_change(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct sock *parent = subflow->conn;
+
+ __subflow_state_change(sk);
+
+ if (subflow_simultaneous_connect(sk)) {
+ mptcp_do_fallback(sk);
+ mptcp_rcv_space_init(mptcp_sk(parent), sk);
+ pr_fallback(mptcp_sk(parent));
+ subflow->conn_finished = 1;
+ if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
+ inet_sk_state_store(parent, TCP_ESTABLISHED);
+ parent->sk_state_change(parent);
+ }
+ }
+
+ /* as recvmsg() does not acquire the subflow socket for ssk selection
+ * a fin packet carrying a DSS can be unnoticed if we don't trigger
+ * the data available machinery here.
+ */
+ if (mptcp_subflow_data_available(sk))
+ mptcp_data_ready(parent, sk);
+
+ if (__mptcp_check_fallback(mptcp_sk(parent)) &&
+ !(parent->sk_shutdown & RCV_SHUTDOWN) &&
+ !subflow->rx_eof && subflow_is_done(sk)) {
+ subflow->rx_eof = 1;
+ mptcp_subflow_eof(parent);
+ }
+}
+
+static int subflow_ulp_init(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct mptcp_subflow_context *ctx;
+ struct tcp_sock *tp = tcp_sk(sk);
+ int err = 0;
+
+ /* disallow attaching ULP to a socket unless it has been
+ * created with sock_create_kern()
+ */
+ if (!sk->sk_kern_sock) {
+ err = -EOPNOTSUPP;
+ goto out;
+ }
+
+ ctx = subflow_create_ctx(sk, GFP_KERNEL);
+ if (!ctx) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ pr_debug("subflow=%p, family=%d", ctx, sk->sk_family);
+
+ tp->is_mptcp = 1;
+ ctx->icsk_af_ops = icsk->icsk_af_ops;
+ icsk->icsk_af_ops = subflow_default_af_ops(sk);
+ ctx->tcp_data_ready = sk->sk_data_ready;
+ ctx->tcp_state_change = sk->sk_state_change;
+ ctx->tcp_write_space = sk->sk_write_space;
+ sk->sk_data_ready = subflow_data_ready;
+ sk->sk_write_space = subflow_write_space;
+ sk->sk_state_change = subflow_state_change;
+out:
+ return err;
+}
+
+static void subflow_ulp_release(struct sock *sk)
+{
+ struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(sk);
+
+ if (!ctx)
+ return;
+
+ if (ctx->conn)
+ sock_put(ctx->conn);
+
+ kfree_rcu(ctx, rcu);
+}
+
+static void subflow_ulp_clone(const struct request_sock *req,
+ struct sock *newsk,
+ const gfp_t priority)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk);
+ struct mptcp_subflow_context *new_ctx;
+
+ if (!tcp_rsk(req)->is_mptcp ||
+ (!subflow_req->mp_capable && !subflow_req->mp_join)) {
+ subflow_ulp_fallback(newsk, old_ctx);
+ return;
+ }
+
+ new_ctx = subflow_create_ctx(newsk, priority);
+ if (!new_ctx) {
+ subflow_ulp_fallback(newsk, old_ctx);
+ return;
+ }
+
+ new_ctx->conn_finished = 1;
+ new_ctx->icsk_af_ops = old_ctx->icsk_af_ops;
+ new_ctx->tcp_data_ready = old_ctx->tcp_data_ready;
+ new_ctx->tcp_state_change = old_ctx->tcp_state_change;
+ new_ctx->tcp_write_space = old_ctx->tcp_write_space;
+ new_ctx->rel_write_seq = 1;
+ new_ctx->tcp_sock = newsk;
+
+ if (subflow_req->mp_capable) {
+ /* see comments in subflow_syn_recv_sock(), MPTCP connection
+ * is fully established only after we receive the remote key
+ */
+ new_ctx->mp_capable = 1;
+ new_ctx->local_key = subflow_req->local_key;
+ new_ctx->token = subflow_req->token;
+ new_ctx->ssn_offset = subflow_req->ssn_offset;
+ new_ctx->idsn = subflow_req->idsn;
+ } else if (subflow_req->mp_join) {
+ new_ctx->ssn_offset = subflow_req->ssn_offset;
+ new_ctx->mp_join = 1;
+ new_ctx->fully_established = 1;
+ new_ctx->backup = subflow_req->backup;
+ new_ctx->local_id = subflow_req->local_id;
+ new_ctx->remote_id = subflow_req->remote_id;
+ new_ctx->token = subflow_req->token;
+ new_ctx->thmac = subflow_req->thmac;
+ }
+}
+
+static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = {
+ .name = "mptcp",
+ .owner = THIS_MODULE,
+ .init = subflow_ulp_init,
+ .release = subflow_ulp_release,
+ .clone = subflow_ulp_clone,
+};
+
+static int subflow_ops_init(struct request_sock_ops *subflow_ops)
+{
+ subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock);
+ subflow_ops->slab_name = "request_sock_subflow";
+
+ subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name,
+ subflow_ops->obj_size, 0,
+ SLAB_ACCOUNT |
+ SLAB_TYPESAFE_BY_RCU,
+ NULL);
+ if (!subflow_ops->slab)
+ return -ENOMEM;
+
+ subflow_ops->destructor = subflow_req_destructor;
+
+ return 0;
+}
+
+void __init mptcp_subflow_init(void)
+{
+ mptcp_subflow_request_sock_ops = tcp_request_sock_ops;
+ if (subflow_ops_init(&mptcp_subflow_request_sock_ops) != 0)
+ panic("MPTCP: failed to init subflow request sock ops\n");
+
+ subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops;
+ subflow_request_sock_ipv4_ops.init_req = subflow_v4_init_req;
+
+ subflow_specific = ipv4_specific;
+ subflow_specific.conn_request = subflow_v4_conn_request;
+ subflow_specific.syn_recv_sock = subflow_syn_recv_sock;
+ subflow_specific.sk_rx_dst_set = subflow_finish_connect;
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops;
+ subflow_request_sock_ipv6_ops.init_req = subflow_v6_init_req;
+
+ subflow_v6_specific = ipv6_specific;
+ subflow_v6_specific.conn_request = subflow_v6_conn_request;
+ subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock;
+ subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect;
+
+ subflow_v6m_specific = subflow_v6_specific;
+ subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit;
+ subflow_v6m_specific.send_check = ipv4_specific.send_check;
+ subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len;
+ subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced;
+ subflow_v6m_specific.net_frag_header_len = 0;
+#endif
+
+ mptcp_diag_subflow_init(&subflow_ulp_ops);
+
+ if (tcp_register_ulp(&subflow_ulp_ops) != 0)
+ panic("MPTCP: failed to register subflows to ULP\n");
+}