diff --git a/include/linux/socket.h b/include/linux/socket.h
index d834af22a4607cd2acfd69490f891e13690c7bae..73bf6c6a833b37b907bc6f8852356d8976b9662d 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -200,7 +200,9 @@ struct ucred {
#define AF_ALG 38 /* Algorithm sockets */
#define AF_NFC 39 /* NFC sockets */
#define AF_VSOCK 40 /* vSockets */
-#define AF_MAX 41 /* For now.. */
+#define AF_KCM 41 /* Kernel Connection Multiplexor*/
+
+#define AF_MAX 42 /* For now.. */
/* Protocol families, same as address families. */
#define PF_UNSPEC AF_UNSPEC
@@ -246,6 +248,7 @@ struct ucred {
#define PF_ALG AF_ALG
#define PF_NFC AF_NFC
#define PF_VSOCK AF_VSOCK
+#define PF_KCM AF_KCM
#define PF_MAX AF_MAX
/* Maximum queue length specifiable by listen. */
@@ -323,6 +326,7 @@ struct ucred {
#define SOL_CAIF 278
#define SOL_ALG 279
#define SOL_NFC 280
+#define SOL_KCM 281
/* IPX options */
#define IPX_TYPE 1
diff --git a/include/net/kcm.h b/include/net/kcm.h
new file mode 100644
index 0000000000000000000000000000000000000000..1bcae39070eca685ee468a1a5e9580e43d4a9600
--- /dev/null
+++ b/include/net/kcm.h
@@ -0,0 +1,125 @@
+/*
+ * Kernel Connection Multiplexor
+ *
+ * Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ */
+
+#ifndef __NET_KCM_H_
+#define __NET_KCM_H_
+
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <uapi/linux/kcm.h>
+
+extern unsigned int kcm_net_id;
+
+struct kcm_tx_msg {
+ unsigned int sent;
+ unsigned int fragidx;
+ unsigned int frag_offset;
+ unsigned int msg_flags;
+ struct sk_buff *frag_skb;
+ struct sk_buff *last_skb;
+};
+
+struct kcm_rx_msg {
+ int full_len;
+ int accum_len;
+ int offset;
+};
+
+/* Socket structure for KCM client sockets */
+struct kcm_sock {
+ struct sock sk;
+ struct kcm_mux *mux;
+ struct list_head kcm_sock_list;
+ int index;
+ u32 done : 1;
+ struct work_struct done_work;
+
+ /* Transmit */
+ struct kcm_psock *tx_psock;
+ struct work_struct tx_work;
+ struct list_head wait_psock_list;
+ struct sk_buff *seq_skb;
+
+ /* Don't use bit fields here, these are set under different locks */
+ bool tx_wait;
+ bool tx_wait_more;
+
+ /* Receive */
+ struct kcm_psock *rx_psock;
+ struct list_head wait_rx_list; /* KCMs waiting for receiving */
+ bool rx_wait;
+ u32 rx_disabled : 1;
+};
+
+struct bpf_prog;
+
+/* Structure for an attached lower socket */
+struct kcm_psock {
+ struct sock *sk;
+ struct kcm_mux *mux;
+ int index;
+
+ u32 tx_stopped : 1;
+ u32 rx_stopped : 1;
+ u32 done : 1;
+ u32 unattaching : 1;
+
+ void (*save_state_change)(struct sock *sk);
+ void (*save_data_ready)(struct sock *sk);
+ void (*save_write_space)(struct sock *sk);
+
+ struct list_head psock_list;
+
+ /* Receive */
+ struct sk_buff *rx_skb_head;
+ struct sk_buff **rx_skb_nextp;
+ struct sk_buff *ready_rx_msg;
+ struct list_head psock_ready_list;
+ struct work_struct rx_work;
+ struct delayed_work rx_delayed_work;
+ struct bpf_prog *bpf_prog;
+ struct kcm_sock *rx_kcm;
+
+ /* Transmit */
+ struct kcm_sock *tx_kcm;
+ struct list_head psock_avail_list;
+};
+
+/* Per net MUX list */
+struct kcm_net {
+ struct mutex mutex;
+ struct list_head mux_list;
+ int count;
+};
+
+/* Structure for a MUX */
+struct kcm_mux {
+ struct list_head kcm_mux_list;
+ struct rcu_head rcu;
+ struct kcm_net *knet;
+
+ struct list_head kcm_socks; /* All KCM sockets on MUX */
+ int kcm_socks_cnt; /* Total KCM socket count for MUX */
+ struct list_head psocks; /* List of all psocks on MUX */
+ int psocks_cnt; /* Total attached sockets */
+
+ /* Receive */
+ spinlock_t rx_lock ____cacheline_aligned_in_smp;
+ struct list_head kcm_rx_waiters; /* KCMs waiting for receiving */
+ struct list_head psocks_ready; /* List of psocks with a msg ready */
+ struct sk_buff_head rx_hold_queue;
+
+ /* Transmit */
+ spinlock_t lock ____cacheline_aligned_in_smp; /* TX and mux locking */
+ struct list_head psocks_avail; /* List of available psocks */
+ struct list_head kcm_tx_waiters; /* KCMs waiting for a TX psock */
+};
+
+#endif /* __NET_KCM_H_ */
diff --git a/include/uapi/linux/kcm.h b/include/uapi/linux/kcm.h
new file mode 100644
index 0000000000000000000000000000000000000000..a5a530940b99c76e2c78b42b2b5f62b3f6fb23b4
--- /dev/null
+++ b/include/uapi/linux/kcm.h
@@ -0,0 +1,40 @@
+/*
+ * Kernel Connection Multiplexor
+ *
+ * Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * User API to clone KCM sockets and attach transport socket to a KCM
+ * multiplexor.
+ */
+
+#ifndef KCM_KERNEL_H
+#define KCM_KERNEL_H
+
+struct kcm_attach {
+ int fd;
+ int bpf_fd;
+};
+
+struct kcm_unattach {
+ int fd;
+};
+
+struct kcm_clone {
+ int fd;
+};
+
+#define SIOCKCMATTACH (SIOCPROTOPRIVATE + 0)
+#define SIOCKCMUNATTACH (SIOCPROTOPRIVATE + 1)
+#define SIOCKCMCLONE (SIOCPROTOPRIVATE + 2)
+
+#define KCMPROTO_CONNECTED 0
+
+/* Socket options */
+#define KCM_RECV_DISABLE 1
+
+#endif
+
diff --git a/net/Kconfig b/net/Kconfig
index 2760825e53fa4e2404571d34c98c965e2b46b9cb..10640d5f8beefd84d41b8d3eff2758c3757e9f6b 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -360,6 +360,7 @@ source "net/can/Kconfig"
source "net/irda/Kconfig"
source "net/bluetooth/Kconfig"
source "net/rxrpc/Kconfig"
+source "net/kcm/Kconfig"
config FIB_RULES
bool
diff --git a/net/Makefile b/net/Makefile
index a5d04098dfce8693c46785f6c0dfa90bd23f4187..81d14119eab5416e8576f1fffa5109d752784143 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_IRDA) += irda/
obj-$(CONFIG_BT) += bluetooth/
obj-$(CONFIG_SUNRPC) += sunrpc/
obj-$(CONFIG_AF_RXRPC) += rxrpc/
+obj-$(CONFIG_AF_KCM) += kcm/
obj-$(CONFIG_ATM) += atm/
obj-$(CONFIG_L2TP) += l2tp/
obj-$(CONFIG_DECNET) += decnet/
diff --git a/net/kcm/Kconfig b/net/kcm/Kconfig
new file mode 100644
index 0000000000000000000000000000000000000000..5db94d940ecc0533fd63c6dd4397d9242a212c47
--- /dev/null
+++ b/net/kcm/Kconfig
@@ -0,0 +1,10 @@
+
+config AF_KCM
+ tristate "KCM sockets"
+ depends on INET
+ select BPF_SYSCALL
+ ---help---
+ KCM (Kernel Connection Multiplexor) sockets provide a method
+ for multiplexing messages of a message based application
+ protocol over kernel connectons (e.g. TCP connections).
+
diff --git a/net/kcm/Makefile b/net/kcm/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..cb525f7c5a133929b2cc5c4eb34623a8275a4fca
--- /dev/null
+++ b/net/kcm/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_AF_KCM) += kcm.o
+
+kcm-y := kcmsock.o
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
new file mode 100644
index 0000000000000000000000000000000000000000..30ef69ac6b81291eae0a5364fcc33eed860688b7
--- /dev/null
+++ b/net/kcm/kcmsock.c
@@ -0,0 +1,2016 @@
+#include <linux/bpf.h>
+#include <linux/errno.h>
+#include <linux/errqueue.h>
+#include <linux/file.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/poll.h>
+#include <linux/rculist.h>
+#include <linux/skbuff.h>
+#include <linux/socket.h>
+#include <linux/uaccess.h>
+#include <linux/workqueue.h>
+#include <net/kcm.h>
+#include <net/netns/generic.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <uapi/linux/kcm.h>
+
+unsigned int kcm_net_id;
+
+static struct kmem_cache *kcm_psockp __read_mostly;
+static struct kmem_cache *kcm_muxp __read_mostly;
+static struct workqueue_struct *kcm_wq;
+
+static inline struct kcm_sock *kcm_sk(const struct sock *sk)
+{
+ return (struct kcm_sock *)sk;
+}
+
+static inline struct kcm_tx_msg *kcm_tx_msg(struct sk_buff *skb)
+{
+ return (struct kcm_tx_msg *)skb->cb;
+}
+
+static inline struct kcm_rx_msg *kcm_rx_msg(struct sk_buff *skb)
+{
+ return (struct kcm_rx_msg *)((void *)skb->cb +
+ offsetof(struct qdisc_skb_cb, data));
+}
+
+static void report_csk_error(struct sock *csk, int err)
+{
+ csk->sk_err = EPIPE;
+ csk->sk_error_report(csk);
+}
+
+/* Callback lock held */
+static void kcm_abort_rx_psock(struct kcm_psock *psock, int err,
+ struct sk_buff *skb)
+{
+ struct sock *csk = psock->sk;
+
+ /* Unrecoverable error in receive */
+
+ if (psock->rx_stopped)
+ return;
+
+ psock->rx_stopped = 1;
+
+ /* Report an error on the lower socket */
+ report_csk_error(csk, err);
+}
+
+static void kcm_abort_tx_psock(struct kcm_psock *psock, int err,
+ bool wakeup_kcm)
+{
+ struct sock *csk = psock->sk;
+ struct kcm_mux *mux = psock->mux;
+
+ /* Unrecoverable error in transmit */
+
+ spin_lock_bh(&mux->lock);
+
+ if (psock->tx_stopped) {
+ spin_unlock_bh(&mux->lock);
+ return;
+ }
+
+ psock->tx_stopped = 1;
+
+ if (!psock->tx_kcm) {
+ /* Take off psocks_avail list */
+ list_del(&psock->psock_avail_list);
+ } else if (wakeup_kcm) {
+ /* In this case psock is being aborted while outside of
+ * write_msgs and psock is reserved. Schedule tx_work
+ * to handle the failure there. Need to commit tx_stopped
+ * before queuing work.
+ */
+ smp_mb();
+
+ queue_work(kcm_wq, &psock->tx_kcm->tx_work);
+ }
+
+ spin_unlock_bh(&mux->lock);
+
+ /* Report error on lower socket */
+ report_csk_error(csk, err);
+}
+
+static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
+
+/* KCM is ready to receive messages on its queue-- either the KCM is new or
+ * has become unblocked after being blocked on full socket buffer. Queue any
+ * pending ready messages on a psock. RX mux lock held.
+ */
+static void kcm_rcv_ready(struct kcm_sock *kcm)
+{
+ struct kcm_mux *mux = kcm->mux;
+ struct kcm_psock *psock;
+ struct sk_buff *skb;
+
+ if (unlikely(kcm->rx_wait || kcm->rx_psock || kcm->rx_disabled))
+ return;
+
+ while (unlikely((skb = __skb_dequeue(&mux->rx_hold_queue)))) {
+ if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
+ /* Assuming buffer limit has been reached */
+ skb_queue_head(&mux->rx_hold_queue, skb);
+ WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
+ return;
+ }
+ }
+
+ while (!list_empty(&mux->psocks_ready)) {
+ psock = list_first_entry(&mux->psocks_ready, struct kcm_psock,
+ psock_ready_list);
+
+ if (kcm_queue_rcv_skb(&kcm->sk, psock->ready_rx_msg)) {
+ /* Assuming buffer limit has been reached */
+ WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
+ return;
+ }
+
+ /* Consumed the ready message on the psock. Schedule rx_work to
+ * get more messages.
+ */
+ list_del(&psock->psock_ready_list);
+ psock->ready_rx_msg = NULL;
+
+ /* Commit clearing of ready_rx_msg for queuing work */
+ smp_mb();
+
+ queue_work(kcm_wq, &psock->rx_work);
+ }
+
+ /* Buffer limit is okay now, add to ready list */
+ list_add_tail(&kcm->wait_rx_list,
+ &kcm->mux->kcm_rx_waiters);
+ kcm->rx_wait = true;
+}
+
+static void kcm_rfree(struct sk_buff *skb)
+{
+ struct sock *sk = skb->sk;
+ struct kcm_sock *kcm = kcm_sk(sk);
+ struct kcm_mux *mux = kcm->mux;
+ unsigned int len = skb->truesize;
+
+ sk_mem_uncharge(sk, len);
+ atomic_sub(len, &sk->sk_rmem_alloc);
+
+ /* For reading rx_wait and rx_psock without holding lock */
+ smp_mb__after_atomic();
+
+ if (!kcm->rx_wait && !kcm->rx_psock &&
+ sk_rmem_alloc_get(sk) < sk->sk_rcvlowat) {
+ spin_lock_bh(&mux->rx_lock);
+ kcm_rcv_ready(kcm);
+ spin_unlock_bh(&mux->rx_lock);
+ }
+}
+
+static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
+{
+ struct sk_buff_head *list = &sk->sk_receive_queue;
+
+ if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
+ return -ENOMEM;
+
+ if (!sk_rmem_schedule(sk, skb, skb->truesize))
+ return -ENOBUFS;
+
+ skb->dev = NULL;
+
+ skb_orphan(skb);
+ skb->sk = sk;
+ skb->destructor = kcm_rfree;
+ atomic_add(skb->truesize, &sk->sk_rmem_alloc);
+ sk_mem_charge(sk, skb->truesize);
+
+ skb_queue_tail(list, skb);
+
+ if (!sock_flag(sk, SOCK_DEAD))
+ sk->sk_data_ready(sk);
+
+ return 0;
+}
+
+/* Requeue received messages for a kcm socket to other kcm sockets. This is
+ * called with a kcm socket is receive disabled.
+ * RX mux lock held.
+ */
+static void requeue_rx_msgs(struct kcm_mux *mux, struct sk_buff_head *head)
+{
+ struct sk_buff *skb;
+ struct kcm_sock *kcm;
+
+ while ((skb = __skb_dequeue(head))) {
+ /* Reset destructor to avoid calling kcm_rcv_ready */
+ skb->destructor = sock_rfree;
+ skb_orphan(skb);
+try_again:
+ if (list_empty(&mux->kcm_rx_waiters)) {
+ skb_queue_tail(&mux->rx_hold_queue, skb);
+ continue;
+ }
+
+ kcm = list_first_entry(&mux->kcm_rx_waiters,
+ struct kcm_sock, wait_rx_list);
+
+ if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
+ /* Should mean socket buffer full */
+ list_del(&kcm->wait_rx_list);
+ kcm->rx_wait = false;
+
+ /* Commit rx_wait to read in kcm_free */
+ smp_wmb();
+
+ goto try_again;
+ }
+ }
+}
+
+/* Lower sock lock held */
+static struct kcm_sock *reserve_rx_kcm(struct kcm_psock *psock,
+ struct sk_buff *head)
+{
+ struct kcm_mux *mux = psock->mux;
+ struct kcm_sock *kcm;
+
+ WARN_ON(psock->ready_rx_msg);
+
+ if (psock->rx_kcm)
+ return psock->rx_kcm;
+
+ spin_lock_bh(&mux->rx_lock);
+
+ if (psock->rx_kcm) {
+ spin_unlock_bh(&mux->rx_lock);
+ return psock->rx_kcm;
+ }
+
+ if (list_empty(&mux->kcm_rx_waiters)) {
+ psock->ready_rx_msg = head;
+ list_add_tail(&psock->psock_ready_list,
+ &mux->psocks_ready);
+ spin_unlock_bh(&mux->rx_lock);
+ return NULL;
+ }
+
+ kcm = list_first_entry(&mux->kcm_rx_waiters,
+ struct kcm_sock, wait_rx_list);
+ list_del(&kcm->wait_rx_list);
+ kcm->rx_wait = false;
+
+ psock->rx_kcm = kcm;
+ kcm->rx_psock = psock;
+
+ spin_unlock_bh(&mux->rx_lock);
+
+ return kcm;
+}
+
+static void kcm_done(struct kcm_sock *kcm);
+
+static void kcm_done_work(struct work_struct *w)
+{
+ kcm_done(container_of(w, struct kcm_sock, done_work));
+}
+
+/* Lower sock held */
+static void unreserve_rx_kcm(struct kcm_psock *psock,
+ bool rcv_ready)
+{
+ struct kcm_sock *kcm = psock->rx_kcm;
+ struct kcm_mux *mux = psock->mux;
+
+ if (!kcm)
+ return;
+
+ spin_lock_bh(&mux->rx_lock);
+
+ psock->rx_kcm = NULL;
+ kcm->rx_psock = NULL;
+
+ /* Commit kcm->rx_psock before sk_rmem_alloc_get to sync with
+ * kcm_rfree
+ */
+ smp_mb();
+
+ if (unlikely(kcm->done)) {
+ spin_unlock_bh(&mux->rx_lock);
+
+ /* Need to run kcm_done in a task since we need to qcquire
+ * callback locks which may already be held here.
+ */
+ INIT_WORK(&kcm->done_work, kcm_done_work);
+ schedule_work(&kcm->done_work);
+ return;
+ }
+
+ if (unlikely(kcm->rx_disabled)) {
+ requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
+ } else if (rcv_ready || unlikely(!sk_rmem_alloc_get(&kcm->sk))) {
+ /* Check for degenerative race with rx_wait that all
+ * data was dequeued (accounted for in kcm_rfree).
+ */
+ kcm_rcv_ready(kcm);
+ }
+ spin_unlock_bh(&mux->rx_lock);
+}
+
+/* Macro to invoke filter function. */
+#define KCM_RUN_FILTER(prog, ctx) \
+ (*prog->bpf_func)(ctx, prog->insnsi)
+
+/* Lower socket lock held */
+static int kcm_tcp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
+ unsigned int orig_offset, size_t orig_len)
+{
+ struct kcm_psock *psock = (struct kcm_psock *)desc->arg.data;
+ struct kcm_rx_msg *rxm;
+ struct kcm_sock *kcm;
+ struct sk_buff *head, *skb;
+ size_t eaten = 0, cand_len;
+ ssize_t extra;
+ int err;
+ bool cloned_orig = false;
+
+ if (psock->ready_rx_msg)
+ return 0;
+
+ head = psock->rx_skb_head;
+ if (head) {
+ /* Message already in progress */
+
+ if (unlikely(orig_offset)) {
+ /* Getting data with a non-zero offset when a message is
+ * in progress is not expected. If it does happen, we
+ * need to clone and pull since we can't deal with
+ * offsets in the skbs for a message expect in the head.
+ */
+ orig_skb = skb_clone(orig_skb, GFP_ATOMIC);
+ if (!orig_skb) {
+ desc->error = -ENOMEM;
+ return 0;
+ }
+ if (!pskb_pull(orig_skb, orig_offset)) {
+ kfree_skb(orig_skb);
+ desc->error = -ENOMEM;
+ return 0;
+ }
+ cloned_orig = true;
+ orig_offset = 0;
+ }
+
+ if (!psock->rx_skb_nextp) {
+ /* We are going to append to the frags_list of head.
+ * Need to unshare the frag_list.
+ */
+ err = skb_unclone(head, GFP_ATOMIC);
+ if (err) {
+ desc->error = err;
+ return 0;
+ }
+
+ if (unlikely(skb_shinfo(head)->frag_list)) {
+ /* We can't append to an sk_buff that already
+ * has a frag_list. We create a new head, point
+ * the frag_list of that to the old head, and
+ * then are able to use the old head->next for
+ * appending to the message.
+ */
+ if (WARN_ON(head->next)) {
+ desc->error = -EINVAL;
+ return 0;
+ }
+
+ skb = alloc_skb(0, GFP_ATOMIC);
+ if (!skb) {
+ desc->error = -ENOMEM;
+ return 0;
+ }
+ skb->len = head->len;
+ skb->data_len = head->len;
+ skb->truesize = head->truesize;
+ *kcm_rx_msg(skb) = *kcm_rx_msg(head);
+ psock->rx_skb_nextp = &head->next;
+ skb_shinfo(skb)->frag_list = head;
+ psock->rx_skb_head = skb;
+ head = skb;
+ } else {
+ psock->rx_skb_nextp =
+ &skb_shinfo(head)->frag_list;
+ }
+ }
+ }
+
+ while (eaten < orig_len) {
+ /* Always clone since we will consume something */
+ skb = skb_clone(orig_skb, GFP_ATOMIC);
+ if (!skb) {
+ desc->error = -ENOMEM;
+ break;
+ }
+
+ cand_len = orig_len - eaten;
+
+ head = psock->rx_skb_head;
+ if (!head) {
+ head = skb;
+ psock->rx_skb_head = head;
+ /* Will set rx_skb_nextp on next packet if needed */
+ psock->rx_skb_nextp = NULL;
+ rxm = kcm_rx_msg(head);
+ memset(rxm, 0, sizeof(*rxm));
+ rxm->offset = orig_offset + eaten;
+ } else {
+ /* Unclone since we may be appending to an skb that we
+ * already share a frag_list with.
+ */
+ err = skb_unclone(skb, GFP_ATOMIC);
+ if (err) {
+ desc->error = err;
+ break;
+ }
+
+ rxm = kcm_rx_msg(head);
+ *psock->rx_skb_nextp = skb;
+ psock->rx_skb_nextp = &skb->next;
+ head->data_len += skb->len;
+ head->len += skb->len;
+ head->truesize += skb->truesize;
+ }
+
+ if (!rxm->full_len) {
+ ssize_t len;
+
+ len = KCM_RUN_FILTER(psock->bpf_prog, head);
+
+ if (!len) {
+ /* Need more header to determine length */
+ rxm->accum_len += cand_len;
+ eaten += cand_len;
+ WARN_ON(eaten != orig_len);
+ break;
+ } else if (len <= (ssize_t)head->len -
+ skb->len - rxm->offset) {
+ /* Length must be into new skb (and also
+ * greater than zero)
+ */
+ desc->error = -EPROTO;
+ psock->rx_skb_head = NULL;
+ kcm_abort_rx_psock(psock, EPROTO, head);
+ break;
+ }
+
+ rxm->full_len = len;
+ }
+
+ extra = (ssize_t)(rxm->accum_len + cand_len) - rxm->full_len;
+
+ if (extra < 0) {
+ /* Message not complete yet. */
+ rxm->accum_len += cand_len;
+ eaten += cand_len;
+ WARN_ON(eaten != orig_len);
+ break;
+ }
+
+ /* Positive extra indicates ore bytes than needed for the
+ * message
+ */
+
+ WARN_ON(extra > cand_len);
+
+ eaten += (cand_len - extra);
+
+ /* Hurray, we have a new message! */
+ psock->rx_skb_head = NULL;
+
+try_queue:
+ kcm = reserve_rx_kcm(psock, head);
+ if (!kcm) {
+ /* Unable to reserve a KCM, message is held in psock. */
+ break;
+ }
+
+ if (kcm_queue_rcv_skb(&kcm->sk, head)) {
+ /* Should mean socket buffer full */
+ unreserve_rx_kcm(psock, false);
+ goto try_queue;
+ }
+ }
+
+ if (cloned_orig)
+ kfree_skb(orig_skb);
+
+ return eaten;
+}
+
+/* Called with lock held on lower socket */
+static int psock_tcp_read_sock(struct kcm_psock *psock)
+{
+ read_descriptor_t desc;
+
+ desc.arg.data = psock;
+ desc.error = 0;
+ desc.count = 1; /* give more than one skb per call */
+
+ /* sk should be locked here, so okay to do tcp_read_sock */
+ tcp_read_sock(psock->sk, &desc, kcm_tcp_recv);
+
+ unreserve_rx_kcm(psock, true);
+
+ return desc.error;
+}
+
+/* Lower sock lock held */
+static void psock_tcp_data_ready(struct sock *sk)
+{
+ struct kcm_psock *psock;
+
+ read_lock_bh(&sk->sk_callback_lock);
+
+ psock = (struct kcm_psock *)sk->sk_user_data;
+ if (unlikely(!psock || psock->rx_stopped))
+ goto out;
+
+ if (psock->ready_rx_msg)
+ goto out;
+
+ if (psock_tcp_read_sock(psock) == -ENOMEM)
+ queue_delayed_work(kcm_wq, &psock->rx_delayed_work, 0);
+
+out:
+ read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void do_psock_rx_work(struct kcm_psock *psock)
+{
+ read_descriptor_t rd_desc;
+ struct sock *csk = psock->sk;
+
+ /* We need the read lock to synchronize with psock_tcp_data_ready. We
+ * need the socket lock for calling tcp_read_sock.
+ */
+ lock_sock(csk);
+ read_lock_bh(&csk->sk_callback_lock);
+
+ if (unlikely(csk->sk_user_data != psock))
+ goto out;
+
+ if (unlikely(psock->rx_stopped))
+ goto out;
+
+ if (psock->ready_rx_msg)
+ goto out;
+
+ rd_desc.arg.data = psock;
+
+ if (psock_tcp_read_sock(psock) == -ENOMEM)
+ queue_delayed_work(kcm_wq, &psock->rx_delayed_work, 0);
+
+out:
+ read_unlock_bh(&csk->sk_callback_lock);
+ release_sock(csk);
+}
+
+static void psock_rx_work(struct work_struct *w)
+{
+ do_psock_rx_work(container_of(w, struct kcm_psock, rx_work));
+}
+
+static void psock_rx_delayed_work(struct work_struct *w)
+{
+ do_psock_rx_work(container_of(w, struct kcm_psock,
+ rx_delayed_work.work));
+}
+
+static void psock_tcp_state_change(struct sock *sk)
+{
+ /* TCP only does a POLLIN for a half close. Do a POLLHUP here
+ * since application will normally not poll with POLLIN
+ * on the TCP sockets.
+ */
+
+ report_csk_error(sk, EPIPE);
+}
+
+static void psock_tcp_write_space(struct sock *sk)
+{
+ struct kcm_psock *psock;
+ struct kcm_mux *mux;
+ struct kcm_sock *kcm;
+
+ read_lock_bh(&sk->sk_callback_lock);
+
+ psock = (struct kcm_psock *)sk->sk_user_data;
+ if (unlikely(!psock))
+ goto out;
+
+ mux = psock->mux;
+
+ spin_lock_bh(&mux->lock);
+
+ /* Check if the socket is reserved so someone is waiting for sending. */
+ kcm = psock->tx_kcm;
+ if (kcm)
+ queue_work(kcm_wq, &kcm->tx_work);
+
+ spin_unlock_bh(&mux->lock);
+out:
+ read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void unreserve_psock(struct kcm_sock *kcm);
+
+/* kcm sock is locked. */
+static struct kcm_psock *reserve_psock(struct kcm_sock *kcm)
+{
+ struct kcm_mux *mux = kcm->mux;
+ struct kcm_psock *psock;
+
+ psock = kcm->tx_psock;
+
+ smp_rmb(); /* Must read tx_psock before tx_wait */
+
+ if (psock) {
+ WARN_ON(kcm->tx_wait);
+ if (unlikely(psock->tx_stopped))
+ unreserve_psock(kcm);
+ else
+ return kcm->tx_psock;
+ }
+
+ spin_lock_bh(&mux->lock);
+
+ /* Check again under lock to see if psock was reserved for this
+ * psock via psock_unreserve.
+ */
+ psock = kcm->tx_psock;
+ if (unlikely(psock)) {
+ WARN_ON(kcm->tx_wait);
+ spin_unlock_bh(&mux->lock);
+ return kcm->tx_psock;
+ }
+
+ if (!list_empty(&mux->psocks_avail)) {
+ psock = list_first_entry(&mux->psocks_avail,
+ struct kcm_psock,
+ psock_avail_list);
+ list_del(&psock->psock_avail_list);
+ if (kcm->tx_wait) {
+ list_del(&kcm->wait_psock_list);
+ kcm->tx_wait = false;
+ }
+ kcm->tx_psock = psock;
+ psock->tx_kcm = kcm;
+ } else if (!kcm->tx_wait) {
+ list_add_tail(&kcm->wait_psock_list,
+ &mux->kcm_tx_waiters);
+ kcm->tx_wait = true;
+ }
+
+ spin_unlock_bh(&mux->lock);
+
+ return psock;
+}
+
+/* mux lock held */
+static void psock_now_avail(struct kcm_psock *psock)
+{
+ struct kcm_mux *mux = psock->mux;
+ struct kcm_sock *kcm;
+
+ if (list_empty(&mux->kcm_tx_waiters)) {
+ list_add_tail(&psock->psock_avail_list,
+ &mux->psocks_avail);
+ } else {
+ kcm = list_first_entry(&mux->kcm_tx_waiters,
+ struct kcm_sock,
+ wait_psock_list);
+ list_del(&kcm->wait_psock_list);
+ kcm->tx_wait = false;
+ psock->tx_kcm = kcm;
+
+ /* Commit before changing tx_psock since that is read in
+ * reserve_psock before queuing work.
+ */
+ smp_mb();
+
+ kcm->tx_psock = psock;
+ queue_work(kcm_wq, &kcm->tx_work);
+ }
+}
+
+/* kcm sock is locked. */
+static void unreserve_psock(struct kcm_sock *kcm)
+{
+ struct kcm_psock *psock;
+ struct kcm_mux *mux = kcm->mux;
+
+ spin_lock_bh(&mux->lock);
+
+ psock = kcm->tx_psock;
+
+ if (WARN_ON(!psock)) {
+ spin_unlock_bh(&mux->lock);
+ return;
+ }
+
+ smp_rmb(); /* Read tx_psock before tx_wait */
+
+ WARN_ON(kcm->tx_wait);
+
+ kcm->tx_psock = NULL;
+ psock->tx_kcm = NULL;
+
+ if (unlikely(psock->tx_stopped)) {
+ if (psock->done) {
+ /* Deferred free */
+ list_del(&psock->psock_list);
+ mux->psocks_cnt--;
+ sock_put(psock->sk);
+ fput(psock->sk->sk_socket->file);
+ kmem_cache_free(kcm_psockp, psock);
+ }
+
+ /* Don't put back on available list */
+
+ spin_unlock_bh(&mux->lock);
+
+ return;
+ }
+
+ psock_now_avail(psock);
+
+ spin_unlock_bh(&mux->lock);
+}
+
+/* Write any messages ready on the kcm socket. Called with kcm sock lock
+ * held. Return bytes actually sent or error.
+ */
+static int kcm_write_msgs(struct kcm_sock *kcm)
+{
+ struct sock *sk = &kcm->sk;
+ struct kcm_psock *psock;
+ struct sk_buff *skb, *head;
+ struct kcm_tx_msg *txm;
+ unsigned short fragidx, frag_offset;
+ unsigned int sent, total_sent = 0;
+ int ret = 0;
+
+ kcm->tx_wait_more = false;
+ psock = kcm->tx_psock;
+ if (unlikely(psock && psock->tx_stopped)) {
+ /* A reserved psock was aborted asynchronously. Unreserve
+ * it and we'll retry the message.
+ */
+ unreserve_psock(kcm);
+ if (skb_queue_empty(&sk->sk_write_queue))
+ return 0;
+
+ kcm_tx_msg(skb_peek(&sk->sk_write_queue))->sent = 0;
+
+ } else if (skb_queue_empty(&sk->sk_write_queue)) {
+ return 0;
+ }
+
+ head = skb_peek(&sk->sk_write_queue);
+ txm = kcm_tx_msg(head);
+
+ if (txm->sent) {
+ /* Send of first skbuff in queue already in progress */
+ if (WARN_ON(!psock)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ sent = txm->sent;
+ frag_offset = txm->frag_offset;
+ fragidx = txm->fragidx;
+ skb = txm->frag_skb;
+
+ goto do_frag;
+ }
+
+try_again:
+ psock = reserve_psock(kcm);
+ if (!psock)
+ goto out;
+
+ do {
+ skb = head;
+ txm = kcm_tx_msg(head);
+ sent = 0;
+
+do_frag_list:
+ if (WARN_ON(!skb_shinfo(skb)->nr_frags)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags;
+ fragidx++) {
+ skb_frag_t *frag;
+
+ frag_offset = 0;
+do_frag:
+ frag = &skb_shinfo(skb)->frags[fragidx];
+ if (WARN_ON(!frag->size)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = kernel_sendpage(psock->sk->sk_socket,
+ frag->page.p,
+ frag->page_offset + frag_offset,
+ frag->size - frag_offset,
+ MSG_DONTWAIT);
+ if (ret <= 0) {
+ if (ret == -EAGAIN) {
+ /* Save state to try again when there's
+ * write space on the socket
+ */
+ txm->sent = sent;
+ txm->frag_offset = frag_offset;
+ txm->fragidx = fragidx;
+ txm->frag_skb = skb;
+
+ ret = 0;
+ goto out;
+ }
+
+ /* Hard failure in sending message, abort this
+ * psock since it has lost framing
+ * synchonization and retry sending the
+ * message from the beginning.
+ */
+ kcm_abort_tx_psock(psock, ret ? -ret : EPIPE,
+ true);
+ unreserve_psock(kcm);
+
+ txm->sent = 0;
+ ret = 0;
+
+ goto try_again;
+ }
+
+ sent += ret;
+ frag_offset += ret;
+ if (frag_offset < frag->size) {
+ /* Not finished with this frag */
+ goto do_frag;
+ }
+ }
+
+ if (skb == head) {
+ if (skb_has_frag_list(skb)) {
+ skb = skb_shinfo(skb)->frag_list;
+ goto do_frag_list;
+ }
+ } else if (skb->next) {
+ skb = skb->next;
+ goto do_frag_list;
+ }
+
+ /* Successfully sent the whole packet, account for it. */
+ skb_dequeue(&sk->sk_write_queue);
+ kfree_skb(head);
+ sk->sk_wmem_queued -= sent;
+ total_sent += sent;
+ } while ((head = skb_peek(&sk->sk_write_queue)));
+out:
+ if (!head) {
+ /* Done with all queued messages. */
+ WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
+ unreserve_psock(kcm);
+ }
+
+ /* Check if write space is available */
+ sk->sk_write_space(sk);
+
+ return total_sent ? : ret;
+}
+
+static void kcm_tx_work(struct work_struct *w)
+{
+ struct kcm_sock *kcm = container_of(w, struct kcm_sock, tx_work);
+ struct sock *sk = &kcm->sk;
+ int err;
+
+ lock_sock(sk);
+
+ /* Primarily for SOCK_DGRAM sockets, also handle asynchronous tx
+ * aborts
+ */
+ err = kcm_write_msgs(kcm);
+ if (err < 0) {
+ /* Hard failure in write, report error on KCM socket */
+ pr_warn("KCM: Hard failure on kcm_write_msgs %d\n", err);
+ report_csk_error(&kcm->sk, -err);
+ goto out;
+ }
+
+ /* Primarily for SOCK_SEQPACKET sockets */
+ if (likely(sk->sk_socket) &&
+ test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
+ clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+ sk->sk_write_space(sk);
+ }
+
+out:
+ release_sock(sk);
+}
+
+static void kcm_push(struct kcm_sock *kcm)
+{
+ if (kcm->tx_wait_more)
+ kcm_write_msgs(kcm);
+}
+
+static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
+{
+ struct sock *sk = sock->sk;
+ struct kcm_sock *kcm = kcm_sk(sk);
+ struct sk_buff *skb = NULL, *head = NULL;
+ size_t copy, copied = 0;
+ long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+ int eor = (sock->type == SOCK_DGRAM) ?
+ !(msg->msg_flags & MSG_MORE) : !!(msg->msg_flags & MSG_EOR);
+ int err = -EPIPE;
+
+ lock_sock(sk);
+
+ /* Per tcp_sendmsg this should be in poll */
+ sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+
+ if (sk->sk_err)
+ goto out_error;
+
+ if (kcm->seq_skb) {
+ /* Previously opened message */
+ head = kcm->seq_skb;
+ skb = kcm_tx_msg(head)->last_skb;
+ goto start;
+ }
+
+ /* Call the sk_stream functions to manage the sndbuf mem. */
+ if (!sk_stream_memory_free(sk)) {
+ kcm_push(kcm);
+ set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+ err = sk_stream_wait_memory(sk, &timeo);
+ if (err)
+ goto out_error;
+ }
+
+ /* New message, alloc head skb */
+ head = alloc_skb(0, sk->sk_allocation);
+ while (!head) {
+ kcm_push(kcm);
+ err = sk_stream_wait_memory(sk, &timeo);
+ if (err)
+ goto out_error;
+
+ head = alloc_skb(0, sk->sk_allocation);
+ }
+
+ skb = head;
+
+ /* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling
+ * csum_and_copy_from_iter from skb_do_copy_data_nocache.
+ */
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+start:
+ while (msg_data_left(msg)) {
+ bool merge = true;
+ int i = skb_shinfo(skb)->nr_frags;
+ struct page_frag *pfrag = sk_page_frag(sk);
+
+ if (!sk_page_frag_refill(sk, pfrag))
+ goto wait_for_memory;
+
+ if (!skb_can_coalesce(skb, i, pfrag->page,
+ pfrag->offset)) {
+ if (i == MAX_SKB_FRAGS) {
+ struct sk_buff *tskb;
+
+ tskb = alloc_skb(0, sk->sk_allocation);
+ if (!tskb)
+ goto wait_for_memory;
+
+ if (head == skb)
+ skb_shinfo(head)->frag_list = tskb;
+ else
+ skb->next = tskb;
+
+ skb = tskb;
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ continue;
+ }
+ merge = false;
+ }
+
+ copy = min_t(int, msg_data_left(msg),
+ pfrag->size - pfrag->offset);
+
+ if (!sk_wmem_schedule(sk, copy))
+ goto wait_for_memory;
+
+ err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
+ pfrag->page,
+ pfrag->offset,
+ copy);
+ if (err)
+ goto out_error;
+
+ /* Update the skb. */
+ if (merge) {
+ skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
+ } else {
+ skb_fill_page_desc(skb, i, pfrag->page,
+ pfrag->offset, copy);
+ get_page(pfrag->page);
+ }
+
+ pfrag->offset += copy;
+ copied += copy;
+ if (head != skb) {
+ head->len += copy;
+ head->data_len += copy;
+ }
+
+ continue;
+
+wait_for_memory:
+ kcm_push(kcm);
+ err = sk_stream_wait_memory(sk, &timeo);
+ if (err)
+ goto out_error;
+ }
+
+ if (eor) {
+ bool not_busy = skb_queue_empty(&sk->sk_write_queue);
+
+ /* Message complete, queue it on send buffer */
+ __skb_queue_tail(&sk->sk_write_queue, head);
+ kcm->seq_skb = NULL;
+
+ if (msg->msg_flags & MSG_BATCH) {
+ kcm->tx_wait_more = true;
+ } else if (kcm->tx_wait_more || not_busy) {
+ err = kcm_write_msgs(kcm);
+ if (err < 0) {
+ /* We got a hard error in write_msgs but have
+ * already queued this message. Report an error
+ * in the socket, but don't affect return value
+ * from sendmsg
+ */
+ pr_warn("KCM: Hard failure on kcm_write_msgs\n");
+ report_csk_error(&kcm->sk, -err);
+ }
+ }
+ } else {
+ /* Message not complete, save state */
+partial_message:
+ kcm->seq_skb = head;
+ kcm_tx_msg(head)->last_skb = skb;
+ }
+
+ release_sock(sk);
+ return copied;
+
+out_error:
+ kcm_push(kcm);
+
+ if (copied && sock->type == SOCK_SEQPACKET) {
+ /* Wrote some bytes before encountering an
+ * error, return partial success.
+ */
+ goto partial_message;
+ }
+
+ if (head != kcm->seq_skb)
+ kfree_skb(head);
+
+ err = sk_stream_error(sk, msg->msg_flags, err);
+
+ /* make sure we wake any epoll edge trigger waiter */
+ if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
+ sk->sk_write_space(sk);
+
+ release_sock(sk);
+ return err;
+}
+
+static struct sk_buff *kcm_wait_data(struct sock *sk, int flags,
+ long timeo, int *err)
+{
+ struct sk_buff *skb;
+
+ while (!(skb = skb_peek(&sk->sk_receive_queue))) {
+ if (sk->sk_err) {
+ *err = sock_error(sk);
+ return NULL;
+ }
+
+ if (sock_flag(sk, SOCK_DONE))
+ return NULL;
+
+ if ((flags & MSG_DONTWAIT) || !timeo) {
+ *err = -EAGAIN;
+ return NULL;
+ }
+
+ sk_wait_data(sk, &timeo, NULL);
+
+ /* Handle signals */
+ if (signal_pending(current)) {
+ *err = sock_intr_errno(timeo);
+ return NULL;
+ }
+ }
+
+ return skb;
+}
+
+static int kcm_recvmsg(struct socket *sock, struct msghdr *msg,
+ size_t len, int flags)
+{
+ struct sock *sk = sock->sk;
+ int err = 0;
+ long timeo;
+ struct kcm_rx_msg *rxm;
+ int copied = 0;
+ struct sk_buff *skb;
+
+ timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+
+ lock_sock(sk);
+
+ skb = kcm_wait_data(sk, flags, timeo, &err);
+ if (!skb)
+ goto out;
+
+ /* Okay, have a message on the receive queue */
+
+ rxm = kcm_rx_msg(skb);
+
+ if (len > rxm->full_len)
+ len = rxm->full_len;
+
+ err = skb_copy_datagram_msg(skb, rxm->offset, msg, len);
+ if (err < 0)
+ goto out;
+
+ copied = len;
+ if (likely(!(flags & MSG_PEEK))) {
+ if (copied < rxm->full_len) {
+ if (sock->type == SOCK_DGRAM) {
+ /* Truncated message */
+ msg->msg_flags |= MSG_TRUNC;
+ goto msg_finished;
+ }
+ rxm->offset += copied;
+ rxm->full_len -= copied;
+ } else {
+msg_finished:
+ /* Finished with message */
+ msg->msg_flags |= MSG_EOR;
+ skb_unlink(skb, &sk->sk_receive_queue);
+ kfree_skb(skb);
+ }
+ }
+
+out:
+ release_sock(sk);
+
+ return copied ? : err;
+}
+
+/* kcm sock lock held */
+static void kcm_recv_disable(struct kcm_sock *kcm)
+{
+ struct kcm_mux *mux = kcm->mux;
+
+ if (kcm->rx_disabled)
+ return;
+
+ spin_lock_bh(&mux->rx_lock);
+
+ kcm->rx_disabled = 1;
+
+ /* If a psock is reserved we'll do cleanup in unreserve */
+ if (!kcm->rx_psock) {
+ if (kcm->rx_wait) {
+ list_del(&kcm->wait_rx_list);
+ kcm->rx_wait = false;
+ }
+
+ requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
+ }
+
+ spin_unlock_bh(&mux->rx_lock);
+}
+
+/* kcm sock lock held */
+static void kcm_recv_enable(struct kcm_sock *kcm)
+{
+ struct kcm_mux *mux = kcm->mux;
+
+ if (!kcm->rx_disabled)
+ return;
+
+ spin_lock_bh(&mux->rx_lock);
+
+ kcm->rx_disabled = 0;
+ kcm_rcv_ready(kcm);
+
+ spin_unlock_bh(&mux->rx_lock);
+}
+
+static int kcm_setsockopt(struct socket *sock, int level, int optname,
+ char __user *optval, unsigned int optlen)
+{
+ struct kcm_sock *kcm = kcm_sk(sock->sk);
+ int val, valbool;
+ int err = 0;
+
+ if (level != SOL_KCM)
+ return -ENOPROTOOPT;
+
+ if (optlen < sizeof(int))
+ return -EINVAL;
+
+ if (get_user(val, (int __user *)optval))
+ return -EINVAL;
+
+ valbool = val ? 1 : 0;
+
+ switch (optname) {
+ case KCM_RECV_DISABLE:
+ lock_sock(&kcm->sk);
+ if (valbool)
+ kcm_recv_disable(kcm);
+ else
+ kcm_recv_enable(kcm);
+ release_sock(&kcm->sk);
+ break;
+ default:
+ err = -ENOPROTOOPT;
+ }
+
+ return err;
+}
+
+static int kcm_getsockopt(struct socket *sock, int level, int optname,
+ char __user *optval, int __user *optlen)
+{
+ struct kcm_sock *kcm = kcm_sk(sock->sk);
+ int val, len;
+
+ if (level != SOL_KCM)
+ return -ENOPROTOOPT;
+
+ if (get_user(len, optlen))
+ return -EFAULT;
+
+ len = min_t(unsigned int, len, sizeof(int));
+ if (len < 0)
+ return -EINVAL;
+
+ switch (optname) {
+ case KCM_RECV_DISABLE:
+ val = kcm->rx_disabled;
+ break;
+ default:
+ return -ENOPROTOOPT;
+ }
+
+ if (put_user(len, optlen))
+ return -EFAULT;
+ if (copy_to_user(optval, &val, len))
+ return -EFAULT;
+ return 0;
+}
+
+static void init_kcm_sock(struct kcm_sock *kcm, struct kcm_mux *mux)
+{
+ struct kcm_sock *tkcm;
+ struct list_head *head;
+ int index = 0;
+
+ /* For SOCK_SEQPACKET sock type, datagram_poll checks the sk_state, so
+ * we set sk_state, otherwise epoll_wait always returns right away with
+ * POLLHUP
+ */
+ kcm->sk.sk_state = TCP_ESTABLISHED;
+
+ /* Add to mux's kcm sockets list */
+ kcm->mux = mux;
+ spin_lock_bh(&mux->lock);
+
+ head = &mux->kcm_socks;
+ list_for_each_entry(tkcm, &mux->kcm_socks, kcm_sock_list) {
+ if (tkcm->index != index)
+ break;
+ head = &tkcm->kcm_sock_list;
+ index++;
+ }
+
+ list_add(&kcm->kcm_sock_list, head);
+ kcm->index = index;
+
+ mux->kcm_socks_cnt++;
+ spin_unlock_bh(&mux->lock);
+
+ INIT_WORK(&kcm->tx_work, kcm_tx_work);
+
+ spin_lock_bh(&mux->rx_lock);
+ kcm_rcv_ready(kcm);
+ spin_unlock_bh(&mux->rx_lock);
+}
+
+static int kcm_attach(struct socket *sock, struct socket *csock,
+ struct bpf_prog *prog)
+{
+ struct kcm_sock *kcm = kcm_sk(sock->sk);
+ struct kcm_mux *mux = kcm->mux;
+ struct sock *csk;
+ struct kcm_psock *psock = NULL, *tpsock;
+ struct list_head *head;
+ int index = 0;
+
+ if (csock->ops->family != PF_INET &&
+ csock->ops->family != PF_INET6)
+ return -EINVAL;
+
+ csk = csock->sk;
+ if (!csk)
+ return -EINVAL;
+
+ /* Only support TCP for now */
+ if (csk->sk_protocol != IPPROTO_TCP)
+ return -EINVAL;
+
+ psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL);
+ if (!psock)
+ return -ENOMEM;
+
+ psock->mux = mux;
+ psock->sk = csk;
+ psock->bpf_prog = prog;
+ INIT_WORK(&psock->rx_work, psock_rx_work);
+ INIT_DELAYED_WORK(&psock->rx_delayed_work, psock_rx_delayed_work);
+
+ sock_hold(csk);
+
+ write_lock_bh(&csk->sk_callback_lock);
+ psock->save_data_ready = csk->sk_data_ready;
+ psock->save_write_space = csk->sk_write_space;
+ psock->save_state_change = csk->sk_state_change;
+ csk->sk_user_data = psock;
+ csk->sk_data_ready = psock_tcp_data_ready;
+ csk->sk_write_space = psock_tcp_write_space;
+ csk->sk_state_change = psock_tcp_state_change;
+ write_unlock_bh(&csk->sk_callback_lock);
+
+ /* Finished initialization, now add the psock to the MUX. */
+ spin_lock_bh(&mux->lock);
+ head = &mux->psocks;
+ list_for_each_entry(tpsock, &mux->psocks, psock_list) {
+ if (tpsock->index != index)
+ break;
+ head = &tpsock->psock_list;
+ index++;
+ }
+
+ list_add(&psock->psock_list, head);
+ psock->index = index;
+
+ mux->psocks_cnt++;
+ psock_now_avail(psock);
+ spin_unlock_bh(&mux->lock);
+
+ /* Schedule RX work in case there are already bytes queued */
+ queue_work(kcm_wq, &psock->rx_work);
+
+ return 0;
+}
+
+static int kcm_attach_ioctl(struct socket *sock, struct kcm_attach *info)
+{
+ struct socket *csock;
+ struct bpf_prog *prog;
+ int err;
+
+ csock = sockfd_lookup(info->fd, &err);
+ if (!csock)
+ return -ENOENT;
+
+ prog = bpf_prog_get(info->bpf_fd);
+ if (IS_ERR(prog)) {
+ err = PTR_ERR(prog);
+ goto out;
+ }
+
+ if (prog->type != BPF_PROG_TYPE_SOCKET_FILTER) {
+ bpf_prog_put(prog);
+ err = -EINVAL;
+ goto out;
+ }
+
+ err = kcm_attach(sock, csock, prog);
+ if (err) {
+ bpf_prog_put(prog);
+ goto out;
+ }
+
+ /* Keep reference on file also */
+
+ return 0;
+out:
+ fput(csock->file);
+ return err;
+}
+
+static void kcm_unattach(struct kcm_psock *psock)
+{
+ struct sock *csk = psock->sk;
+ struct kcm_mux *mux = psock->mux;
+
+ /* Stop getting callbacks from TCP socket. After this there should
+ * be no way to reserve a kcm for this psock.
+ */
+ write_lock_bh(&csk->sk_callback_lock);
+ csk->sk_user_data = NULL;
+ csk->sk_data_ready = psock->save_data_ready;
+ csk->sk_write_space = psock->save_write_space;
+ csk->sk_state_change = psock->save_state_change;
+ psock->rx_stopped = 1;
+
+ if (WARN_ON(psock->rx_kcm)) {
+ write_unlock_bh(&csk->sk_callback_lock);
+ return;
+ }
+
+ spin_lock_bh(&mux->rx_lock);
+
+ /* Stop receiver activities. After this point psock should not be
+ * able to get onto ready list either through callbacks or work.
+ */
+ if (psock->ready_rx_msg) {
+ list_del(&psock->psock_ready_list);
+ kfree_skb(psock->ready_rx_msg);
+ psock->ready_rx_msg = NULL;
+ }
+
+ spin_unlock_bh(&mux->rx_lock);
+
+ write_unlock_bh(&csk->sk_callback_lock);
+
+ cancel_work_sync(&psock->rx_work);
+ cancel_delayed_work_sync(&psock->rx_delayed_work);
+
+ bpf_prog_put(psock->bpf_prog);
+
+ kfree_skb(psock->rx_skb_head);
+ psock->rx_skb_head = NULL;
+
+ spin_lock_bh(&mux->lock);
+
+ if (psock->tx_kcm) {
+ /* psock was reserved. Just mark it finished and we will clean
+ * up in the kcm paths, we need kcm lock which can not be
+ * acquired here.
+ */
+ spin_unlock_bh(&mux->lock);
+
+ /* We are unattaching a socket that is reserved. Abort the
+ * socket since we may be out of sync in sending on it. We need
+ * to do this without the mux lock.
+ */
+ kcm_abort_tx_psock(psock, EPIPE, false);
+
+ spin_lock_bh(&mux->lock);
+ if (!psock->tx_kcm) {
+ /* psock now unreserved in window mux was unlocked */
+ goto no_reserved;
+ }
+ psock->done = 1;
+
+ /* Commit done before queuing work to process it */
+ smp_mb();
+
+ /* Queue tx work to make sure psock->done is handled */
+ queue_work(kcm_wq, &psock->tx_kcm->tx_work);
+ spin_unlock_bh(&mux->lock);
+ } else {
+no_reserved:
+ if (!psock->tx_stopped)
+ list_del(&psock->psock_avail_list);
+ list_del(&psock->psock_list);
+ mux->psocks_cnt--;
+ spin_unlock_bh(&mux->lock);
+
+ sock_put(csk);
+ fput(csk->sk_socket->file);
+ kmem_cache_free(kcm_psockp, psock);
+ }
+}
+
+static int kcm_unattach_ioctl(struct socket *sock, struct kcm_unattach *info)
+{
+ struct kcm_sock *kcm = kcm_sk(sock->sk);
+ struct kcm_mux *mux = kcm->mux;
+ struct kcm_psock *psock;
+ struct socket *csock;
+ struct sock *csk;
+ int err;
+
+ csock = sockfd_lookup(info->fd, &err);
+ if (!csock)
+ return -ENOENT;
+
+ csk = csock->sk;
+ if (!csk) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ err = -ENOENT;
+
+ spin_lock_bh(&mux->lock);
+
+ list_for_each_entry(psock, &mux->psocks, psock_list) {
+ if (psock->sk != csk)
+ continue;
+
+ /* Found the matching psock */
+
+ if (psock->unattaching || WARN_ON(psock->done)) {
+ err = -EALREADY;
+ break;
+ }
+
+ psock->unattaching = 1;
+
+ spin_unlock_bh(&mux->lock);
+
+ kcm_unattach(psock);
+
+ err = 0;
+ goto out;
+ }
+
+ spin_unlock_bh(&mux->lock);
+
+out:
+ fput(csock->file);
+ return err;
+}
+
+static struct proto kcm_proto = {
+ .name = "KCM",
+ .owner = THIS_MODULE,
+ .obj_size = sizeof(struct kcm_sock),
+};
+
+/* Clone a kcm socket. */
+static int kcm_clone(struct socket *osock, struct kcm_clone *info,
+ struct socket **newsockp)
+{
+ struct socket *newsock;
+ struct sock *newsk;
+ struct file *newfile;
+ int err, newfd;
+
+ err = -ENFILE;
+ newsock = sock_alloc();
+ if (!newsock)
+ goto out;
+
+ newsock->type = osock->type;
+ newsock->ops = osock->ops;
+
+ __module_get(newsock->ops->owner);
+
+ newfd = get_unused_fd_flags(0);
+ if (unlikely(newfd < 0)) {
+ err = newfd;
+ goto out_fd_fail;
+ }
+
+ newfile = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);
+ if (unlikely(IS_ERR(newfile))) {
+ err = PTR_ERR(newfile);
+ goto out_sock_alloc_fail;
+ }
+
+ newsk = sk_alloc(sock_net(osock->sk), PF_KCM, GFP_KERNEL,
+ &kcm_proto, true);
+ if (!newsk) {
+ err = -ENOMEM;
+ goto out_sk_alloc_fail;
+ }
+
+ sock_init_data(newsock, newsk);
+ init_kcm_sock(kcm_sk(newsk), kcm_sk(osock->sk)->mux);
+
+ fd_install(newfd, newfile);
+ *newsockp = newsock;
+ info->fd = newfd;
+
+ return 0;
+
+out_sk_alloc_fail:
+ fput(newfile);
+out_sock_alloc_fail:
+ put_unused_fd(newfd);
+out_fd_fail:
+ sock_release(newsock);
+out:
+ return err;
+}
+
+static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+ int err;
+
+ switch (cmd) {
+ case SIOCKCMATTACH: {
+ struct kcm_attach info;
+
+ if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
+ err = -EFAULT;
+
+ err = kcm_attach_ioctl(sock, &info);
+
+ break;
+ }
+ case SIOCKCMUNATTACH: {
+ struct kcm_unattach info;
+
+ if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
+ err = -EFAULT;
+
+ err = kcm_unattach_ioctl(sock, &info);
+
+ break;
+ }
+ case SIOCKCMCLONE: {
+ struct kcm_clone info;
+ struct socket *newsock = NULL;
+
+ if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
+ err = -EFAULT;
+
+ err = kcm_clone(sock, &info, &newsock);
+
+ if (!err) {
+ if (copy_to_user((void __user *)arg, &info,
+ sizeof(info))) {
+ err = -EFAULT;
+ sock_release(newsock);
+ }
+ }
+
+ break;
+ }
+ default:
+ err = -ENOIOCTLCMD;
+ break;
+ }
+
+ return err;
+}
+
+static void free_mux(struct rcu_head *rcu)
+{
+ struct kcm_mux *mux = container_of(rcu,
+ struct kcm_mux, rcu);
+
+ kmem_cache_free(kcm_muxp, mux);
+}
+
+static void release_mux(struct kcm_mux *mux)
+{
+ struct kcm_net *knet = mux->knet;
+ struct kcm_psock *psock, *tmp_psock;
+
+ /* Release psocks */
+ list_for_each_entry_safe(psock, tmp_psock,
+ &mux->psocks, psock_list) {
+ if (!WARN_ON(psock->unattaching))
+ kcm_unattach(psock);
+ }
+
+ if (WARN_ON(mux->psocks_cnt))
+ return;
+
+ __skb_queue_purge(&mux->rx_hold_queue);
+
+ mutex_lock(&knet->mutex);
+ list_del_rcu(&mux->kcm_mux_list);
+ knet->count--;
+ mutex_unlock(&knet->mutex);
+
+ call_rcu(&mux->rcu, free_mux);
+}
+
+static void kcm_done(struct kcm_sock *kcm)
+{
+ struct kcm_mux *mux = kcm->mux;
+ struct sock *sk = &kcm->sk;
+ int socks_cnt;
+
+ spin_lock_bh(&mux->rx_lock);
+ if (kcm->rx_psock) {
+ /* Cleanup in unreserve_rx_kcm */
+ WARN_ON(kcm->done);
+ kcm->rx_disabled = 1;
+ kcm->done = 1;
+ spin_unlock_bh(&mux->rx_lock);
+ return;
+ }
+
+ if (kcm->rx_wait) {
+ list_del(&kcm->wait_rx_list);
+ kcm->rx_wait = false;
+ }
+ /* Move any pending receive messages to other kcm sockets */
+ requeue_rx_msgs(mux, &sk->sk_receive_queue);
+
+ spin_unlock_bh(&mux->rx_lock);
+
+ if (WARN_ON(sk_rmem_alloc_get(sk)))
+ return;
+
+ /* Detach from MUX */
+ spin_lock_bh(&mux->lock);
+
+ list_del(&kcm->kcm_sock_list);
+ mux->kcm_socks_cnt--;
+ socks_cnt = mux->kcm_socks_cnt;
+
+ spin_unlock_bh(&mux->lock);
+
+ if (!socks_cnt) {
+ /* We are done with the mux now. */
+ release_mux(mux);
+ }
+
+ WARN_ON(kcm->rx_wait);
+
+ sock_put(&kcm->sk);
+}
+
+/* Called by kcm_release to close a KCM socket.
+ * If this is the last KCM socket on the MUX, destroy the MUX.
+ */
+static int kcm_release(struct socket *sock)
+{
+ struct sock *sk = sock->sk;
+ struct kcm_sock *kcm;
+ struct kcm_mux *mux;
+ struct kcm_psock *psock;
+
+ if (!sk)
+ return 0;
+
+ kcm = kcm_sk(sk);
+ mux = kcm->mux;
+
+ sock_orphan(sk);
+ kfree_skb(kcm->seq_skb);
+
+ lock_sock(sk);
+ /* Purge queue under lock to avoid race condition with tx_work trying
+ * to act when queue is nonempty. If tx_work runs after this point
+ * it will just return.
+ */
+ __skb_queue_purge(&sk->sk_write_queue);
+ release_sock(sk);
+
+ spin_lock_bh(&mux->lock);
+ if (kcm->tx_wait) {
+ /* Take of tx_wait list, after this point there should be no way
+ * that a psock will be assigned to this kcm.
+ */
+ list_del(&kcm->wait_psock_list);
+ kcm->tx_wait = false;
+ }
+ spin_unlock_bh(&mux->lock);
+
+ /* Cancel work. After this point there should be no outside references
+ * to the kcm socket.
+ */
+ cancel_work_sync(&kcm->tx_work);
+
+ lock_sock(sk);
+ psock = kcm->tx_psock;
+ if (psock) {
+ /* A psock was reserved, so we need to kill it since it
+ * may already have some bytes queued from a message. We
+ * need to do this after removing kcm from tx_wait list.
+ */
+ kcm_abort_tx_psock(psock, EPIPE, false);
+ unreserve_psock(kcm);
+ }
+ release_sock(sk);
+
+ WARN_ON(kcm->tx_wait);
+ WARN_ON(kcm->tx_psock);
+
+ sock->sk = NULL;
+
+ kcm_done(kcm);
+
+ return 0;
+}
+
+static const struct proto_ops kcm_ops = {
+ .family = PF_KCM,
+ .owner = THIS_MODULE,
+ .release = kcm_release,
+ .bind = sock_no_bind,
+ .connect = sock_no_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = sock_no_accept,
+ .getname = sock_no_getname,
+ .poll = datagram_poll,
+ .ioctl = kcm_ioctl,
+ .listen = sock_no_listen,
+ .shutdown = sock_no_shutdown,
+ .setsockopt = kcm_setsockopt,
+ .getsockopt = kcm_getsockopt,
+ .sendmsg = kcm_sendmsg,
+ .recvmsg = kcm_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = sock_no_sendpage,
+};
+
+/* Create proto operation for kcm sockets */
+static int kcm_create(struct net *net, struct socket *sock,
+ int protocol, int kern)
+{
+ struct kcm_net *knet = net_generic(net, kcm_net_id);
+ struct sock *sk;
+ struct kcm_mux *mux;
+
+ switch (sock->type) {
+ case SOCK_DGRAM:
+ case SOCK_SEQPACKET:
+ sock->ops = &kcm_ops;
+ break;
+ default:
+ return -ESOCKTNOSUPPORT;
+ }
+
+ if (protocol != KCMPROTO_CONNECTED)
+ return -EPROTONOSUPPORT;
+
+ sk = sk_alloc(net, PF_KCM, GFP_KERNEL, &kcm_proto, kern);
+ if (!sk)
+ return -ENOMEM;
+
+ /* Allocate a kcm mux, shared between KCM sockets */
+ mux = kmem_cache_zalloc(kcm_muxp, GFP_KERNEL);
+ if (!mux) {
+ sk_free(sk);
+ return -ENOMEM;
+ }
+
+ spin_lock_init(&mux->lock);
+ spin_lock_init(&mux->rx_lock);
+ INIT_LIST_HEAD(&mux->kcm_socks);
+ INIT_LIST_HEAD(&mux->kcm_rx_waiters);
+ INIT_LIST_HEAD(&mux->kcm_tx_waiters);
+
+ INIT_LIST_HEAD(&mux->psocks);
+ INIT_LIST_HEAD(&mux->psocks_ready);
+ INIT_LIST_HEAD(&mux->psocks_avail);
+
+ mux->knet = knet;
+
+ /* Add new MUX to list */
+ mutex_lock(&knet->mutex);
+ list_add_rcu(&mux->kcm_mux_list, &knet->mux_list);
+ knet->count++;
+ mutex_unlock(&knet->mutex);
+
+ skb_queue_head_init(&mux->rx_hold_queue);
+
+ /* Init KCM socket */
+ sock_init_data(sock, sk);
+ init_kcm_sock(kcm_sk(sk), mux);
+
+ return 0;
+}
+
+static struct net_proto_family kcm_family_ops = {
+ .family = PF_KCM,
+ .create = kcm_create,
+ .owner = THIS_MODULE,
+};
+
+static __net_init int kcm_init_net(struct net *net)
+{
+ struct kcm_net *knet = net_generic(net, kcm_net_id);
+
+ INIT_LIST_HEAD_RCU(&knet->mux_list);
+ mutex_init(&knet->mutex);
+
+ return 0;
+}
+
+static __net_exit void kcm_exit_net(struct net *net)
+{
+ struct kcm_net *knet = net_generic(net, kcm_net_id);
+
+ /* All KCM sockets should be closed at this point, which should mean
+ * that all multiplexors and psocks have been destroyed.
+ */
+ WARN_ON(!list_empty(&knet->mux_list));
+}
+
+static struct pernet_operations kcm_net_ops = {
+ .init = kcm_init_net,
+ .exit = kcm_exit_net,
+ .id = &kcm_net_id,
+ .size = sizeof(struct kcm_net),
+};
+
+static int __init kcm_init(void)
+{
+ int err = -ENOMEM;
+
+ kcm_muxp = kmem_cache_create("kcm_mux_cache",
+ sizeof(struct kcm_mux), 0,
+ SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
+ if (!kcm_muxp)
+ goto fail;
+
+ kcm_psockp = kmem_cache_create("kcm_psock_cache",
+ sizeof(struct kcm_psock), 0,
+ SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
+ if (!kcm_psockp)
+ goto fail;
+
+ kcm_wq = create_singlethread_workqueue("kkcmd");
+ if (!kcm_wq)
+ goto fail;
+
+ err = proto_register(&kcm_proto, 1);
+ if (err)
+ goto fail;
+
+ err = sock_register(&kcm_family_ops);
+ if (err)
+ goto sock_register_fail;
+
+ err = register_pernet_device(&kcm_net_ops);
+ if (err)
+ goto net_ops_fail;
+
+ return 0;
+
+net_ops_fail:
+ sock_unregister(PF_KCM);
+
+sock_register_fail:
+ proto_unregister(&kcm_proto);
+
+fail:
+ kmem_cache_destroy(kcm_muxp);
+ kmem_cache_destroy(kcm_psockp);
+
+ if (kcm_wq)
+ destroy_workqueue(kcm_wq);
+
+ return err;
+}
+
+static void __exit kcm_exit(void)
+{
+ unregister_pernet_device(&kcm_net_ops);
+ sock_unregister(PF_KCM);
+ proto_unregister(&kcm_proto);
+ destroy_workqueue(kcm_wq);
+
+ kmem_cache_destroy(kcm_muxp);
+ kmem_cache_destroy(kcm_psockp);
+}
+
+module_init(kcm_init);
+module_exit(kcm_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETPROTO(PF_KCM);
+