[PATCH V2 net-next 05/15] smc: CLC handshake (incl. preparation steps)

Ursula Braun
2016-09-27T16:41:46Z

* CLC (Connection Layer Control) handshake

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
---
net/smc/Makefile | 2 +-
net/smc/af_smc.c | 467 ++++++++++++++++++++++++++++++++++++++++++++++++++----
net/smc/smc.h | 24 ++-
net/smc/smc_clc.c | 251 +++++++++++++++++++++++++++++
net/smc/smc_clc.h | 111 +++++++++++++
5 files changed, 824 insertions(+), 31 deletions(-)
create mode 100644 net/smc/smc_clc.c
create mode 100644 net/smc/smc_clc.h

diff --git a/net/smc/Makefile b/net/smc/Makefile
index 50f39ff..c0ad588 100644
--- a/net/smc/Makefile
+++ b/net/smc/Makefile
@@ -1,2 +1,2 @@
obj-$(CONFIG_SMC) += smc.o
-smc-y := af_smc.o smc_pnet.o smc_ib.o
+smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 2fa3042..f8c60db 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -6,6 +6,13 @@
* offers an alternative communication option for TCP-protocol sockets
* applicable with RoCE-cards only
*
+ * Initial restrictions:
+ * - non-blocking connect postponed
+ * - IPv6 support postponed
+ * - support for alternate links postponed
+ * - partial support for non-blocking sockets only
+ * - support for urgent data postponed
+ *
* Copyright IBM Corp. 2016
*
* Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
@@ -17,12 +24,18 @@

#include <linux/module.h>
#include <linux/socket.h>
+#include <linux/inetdevice.h>
+#include <linux/workqueue.h>
#include <net/sock.h>
+#include <net/tcp.h>

#include "smc.h"
+#include "smc_clc.h"
#include "smc_ib.h"
#include "smc_pnet.h"

+static void smc_tcp_listen_work(struct work_struct *);
+
static void smc_set_keepalive(struct sock *sk, int val)
{
struct smc_sock *smc = smc_sk(sk);
@@ -94,6 +107,11 @@ static struct sock *smc_sock_alloc(struct net *net, struct socket *sock)
smc = smc_sk(sk);
smc->clcsock = NULL;
smc->use_fallback = 0;
+ smc->addr = NULL;
+ smc->listen_smc = NULL;
+ INIT_WORK(&smc->tcp_listen_work, smc_tcp_listen_work);
+ INIT_LIST_HEAD(&smc->accept_q);
+ spin_lock_init(&smc->accept_q_lock);

return sk;
}
@@ -187,6 +205,123 @@ static void smc_copy_sock_settings_to_smc(struct smc_sock *smc)
smc_copy_sock_settings(&smc->sk, smc->clcsock->sk, SK_FLAGS_CLC_TO_SMC);
}

+/* determine subnet and mask of internal TCP socket */
+int smc_netinfo_by_tcpsk(struct socket *clcsock,
+ __be32 *subnet, u8 *prefix_len)
+{
+ struct dst_entry *dst = sk_dst_get(clcsock->sk);
+ struct sockaddr_in addr;
+ int rc = -ENOENT;
+ int len;
+
+ if (!dst) {
+ rc = -ENOTCONN;
+ goto out;
+ }
+ if (!dst->dev) {
+ rc = -ENODEV;
+ goto out_rel;
+ }
+
+ /* get address to which the internal TCP socket is bound */
+ kernel_getsockname(clcsock, (struct sockaddr *)&addr, &len);
+ /* analyze IPv4 specific data of net_device belonging to TCP socket */
+ for_ifa(dst->dev->ip_ptr) {
+ if (ifa->ifa_address != addr.sin_addr.s_addr)
+ continue;
+ *prefix_len = inet_mask_len(ifa->ifa_mask);
+ *subnet = ifa->ifa_address & ifa->ifa_mask;
+ rc = 0;
+ break;
+ } endfor_ifa(dst->dev->ip_ptr);
+
+out_rel:
+ dst_release(dst);
+out:
+ return rc;
+}
+
+/* setup for RDMA connection of client */
+static int smc_connect_rdma(struct smc_sock *smc)
+{
+ struct smc_clc_msg_accept_confirm aclc;
+ struct smc_ib_device *smcibdev;
+ int reason_code = 0;
+ int rc = 0;
+ u8 ibport;
+
+ if (smc->clc_started)
+ return rc;
+ smc->clc_started = 1;
+
+ /* IPSec connections opt out of SMC-R optimizations */
+ if (using_ipsec(smc)) {
+ reason_code = SMC_CLC_DECL_IPSEC;
+ goto decline_rdma;
+ }
+
+ /* PNET table look up: search active ib_device and port
+ * within same PNETID that also contains the ethernet device
+ * used for the internal TCP socket
+ */
+ smc_pnet_find_roce_resource(smc->clcsock->sk, &smcibdev, &ibport);
+ if (!smcibdev) {
+ reason_code = SMC_CLC_DECL_CNFERR; /* configuration error */
+ goto decline_rdma;
+ }
+
+ /* do inband token exchange */
+ reason_code = smc_clc_send_proposal(smc, smcibdev, ibport);
+ if (reason_code < 0) {
+ rc = reason_code;
+ goto out_err;
+ }
+ if (reason_code > 0) /* configuration error */
+ goto decline_rdma;
+ /* receive SMC Accept CLC message */
+ reason_code = smc_clc_wait_msg(smc, &aclc, sizeof(aclc),
+ SMC_CLC_ACCEPT);
+ if (reason_code < 0) {
+ rc = reason_code;
+ goto out_err;
+ }
+ if (reason_code > 0)
+ goto decline_rdma;
+
+ /* tbd in follow-on patch: more steps to setup RDMA communcication,
+ * create connection, link group, link
+ */
+
+ /* tbd in follow-on patch: more steps to setup RDMA communcication,
+ * create rmbs, map rmbs, rtoken_handling, modify_qp
+ */
+
+ rc = smc_clc_send_confirm(smc);
+ if (rc)
+ goto out_err;
+
+ /* tbd in follow-on patch: llc_confirm */
+
+out_connected:
+ smc_copy_sock_settings_to_clc(smc);
+ smc->sk.sk_state = SMC_ACTIVE;
+
+ return rc;
+
+decline_rdma:
+ /* RDMA setup failed, switch back to TCP */
+ smc->use_fallback = 1;
+ if (reason_code && (reason_code != SMC_CLC_DECL_REPLY)) {
+ rc = smc_clc_send_decline(smc, reason_code, 0);
+ if (rc < sizeof(struct smc_clc_msg_decline))
+ goto out_err;
+ }
+ goto out_connected;
+
+out_err:
+ return rc;
+}
+
static int smc_connect(struct socket *sock, struct sockaddr *addr,
int alen, int flags)
{
@@ -201,6 +336,7 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr,
goto out_err;
if (addr->sa_family != AF_INET)
goto out_err;
+ smc->addr = addr; /* needed for nonblocking connect */

lock_sock(sk);
switch (sk->sk_state) {
@@ -219,12 +355,12 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr,
if (rc)
goto out;

- sk->sk_state = SMC_ACTIVE;
-
- /* always use TCP fallback as transport mechanism for now;
- * This will change once RDMA transport is implemented
- */
- smc->use_fallback = 1;
+ /* setup RDMA connection */
+ rc = smc_connect_rdma(smc);
+ if (rc < 0)
+ goto out;
+ else
+ rc = 0; /* success cases including fallback */

out:
release_sock(sk);
@@ -239,17 +375,32 @@ static int smc_clcsock_accept(struct smc_sock *lsmc, struct smc_sock **new_smc)
struct sock *new_sk;
int rc;

+ release_sock(&lsmc->sk);
new_sk = smc_sock_alloc(sock_net(sk), NULL);
if (!new_sk) {
rc = -ENOMEM;
lsmc->sk.sk_err = ENOMEM;
*new_smc = NULL;
+ lock_sock(&lsmc->sk);
goto out;
}
*new_smc = smc_sk(new_sk);

rc = kernel_accept(lsmc->clcsock, &new_clcsock, 0);
- if (rc) {
+ lock_sock(&lsmc->sk);
+ if (rc < 0) {
+ lsmc->sk.sk_err = -rc;
+ new_sk->sk_state = SMC_CLOSED;
+ sock_set_flag(new_sk, SOCK_DEAD);
+ sock_put(new_sk);
+ *new_smc = NULL;
+ goto out;
+ }
+ if (lsmc->sk.sk_state == SMC_CLOSED) {
+ if (new_clcsock)
+ sock_release(new_clcsock);
+ new_sk->sk_state = SMC_CLOSED;
+ sock_set_flag(new_sk, SOCK_DEAD);
sock_put(new_sk);
*new_smc = NULL;
goto out;
@@ -260,6 +411,216 @@ out:
return rc;
}

+/* add a just created sock to the accept queue of the listen sock as
+ * candidate for a following socket accept call from user space
+ */
+static void smc_accept_enqueue(struct sock *parent, struct sock *sk)
+{
+ struct smc_sock *par = smc_sk(parent);
+
+ sock_hold(sk);
+ spin_lock(&par->accept_q_lock);
+ list_add_tail(&smc_sk(sk)->accept_q, &par->accept_q);
+ spin_unlock(&par->accept_q_lock);
+ sk_acceptq_added(parent);
+}
+
+/* remove a socket from the accept queue of its parental listening socket */
+static void smc_accept_unlink(struct sock *sk)
+{
+ struct smc_sock *par = smc_sk(sk)->listen_smc;
+
+ spin_lock(&par->accept_q_lock);
+ list_del_init(&smc_sk(sk)->accept_q);
+ spin_unlock(&par->accept_q_lock);
+ sk_acceptq_removed(&smc_sk(sk)->listen_smc->sk);
+ sock_put(sk);
+}
+
+/* remove a sock from the accept queue to bind it to a new socket created
+ * for a socket accept call from user space
+ */
+static struct sock *smc_accept_dequeue(struct sock *parent,
+ struct socket *new_sock)
+{
+ struct smc_sock *isk, *n;
+ struct sock *new_sk;
+
+ list_for_each_entry_safe(isk, n, &smc_sk(parent)->accept_q, accept_q) {
+ new_sk = (struct sock *)isk;
+
+ smc_accept_unlink(new_sk);
+ if (new_sk->sk_state == SMC_CLOSED) {
+ /* tbd in follow-on patch: close this sock */
+ continue;
+ }
+ if (new_sock)
+ sock_graft(new_sk, new_sock);
+ return new_sk;
+ }
+ return NULL;
+}
+
+/* clean up for a created but never accepted sock */
+static void smc_close_non_accepted(struct sock *sk)
+{
+ struct smc_sock *smc = smc_sk(sk);
+
+ sock_hold(sk);
+ if (smc->clcsock) {
+ struct socket *tcp;
+
+ tcp = smc->clcsock;
+ smc->clcsock = NULL;
+ sock_release(tcp);
+ }
+ /* more closing stuff to be added with socket closing patch */
+ sock_put(sk);
+}
+
+/* setup for RDMA connection of server */
+static void smc_listen_work(struct work_struct *work)
+{
+ struct smc_sock *new_smc = container_of(work, struct smc_sock,
+ smc_listen_work);
+ struct socket *newclcsock = new_smc->clcsock;
+ struct smc_sock *lsmc = new_smc->listen_smc;
+ struct smc_clc_msg_accept_confirm cclc;
+ struct sock *newsmcsk = &new_smc->sk;
+ struct smc_clc_msg_proposal pclc;
+ struct smc_ib_device *smcibdev;
+ struct sockaddr_in peeraddr;
+ int reason_code = 0;
+ int rc = 0, len;
+ __be32 subnet;
+ u8 prefix_len;
+ u8 ibport;
+
+ /* do inband token exchange -
+ *wait for and receive SMC Proposal CLC message
+ */
+ reason_code = smc_clc_wait_msg(new_smc, &pclc, sizeof(pclc),
+ SMC_CLC_PROPOSAL);
+ if (reason_code < 0)
+ goto out_err;
+ if (reason_code > 0)
+ goto decline_rdma;
+
+ /* IPSec connections opt out of SMC-R optimizations */
+ if (using_ipsec(new_smc)) {
+ reason_code = SMC_CLC_DECL_IPSEC;
+ goto decline_rdma;
+ }
+
+ /* PNET table look up: search active ib_device and port
+ * within same PNETID that also contains the ethernet device
+ * used for the internal TCP socket
+ */
+ smc_pnet_find_roce_resource(newclcsock->sk, &smcibdev, &ibport);
+ if (!smcibdev) {
+ reason_code = SMC_CLC_DECL_CNFERR; /* configuration error */
+ goto decline_rdma;
+ }
+
+ /* determine subnet and mask from internal TCP socket */
+ rc = smc_netinfo_by_tcpsk(newclcsock, &subnet, &prefix_len);
+ if (rc) {
+ reason_code = SMC_CLC_DECL_CNFERR; /* configuration error */
+ goto decline_rdma;
+ }
+ if ((pclc.outgoing_subnet != subnet) ||
+ (pclc.prefix_len != prefix_len)) {
+ reason_code = SMC_CLC_DECL_CNFERR; /* configuration error */
+ goto decline_rdma;
+ }
+
+ /* get address of the peer connected to the internal TCP socket */
+ kernel_getpeername(newclcsock, (struct sockaddr *)&peeraddr, &len);
+
+ /* tbd in follow-on patch: more steps to setup RDMA communcication,
+ * create connection, link_group, link
+ */
+
+ /* tbd in follow-on patch: more steps to setup RDMA communcication,
+ * create rmbs, map rmbs
+ */
+
+ rc = smc_clc_send_accept(new_smc);
+ if (rc)
+ goto out_err;
+
+ /* receive SMC Confirm CLC message */
+ reason_code = smc_clc_wait_msg(new_smc, &cclc, sizeof(cclc),
+ SMC_CLC_CONFIRM);
+ if (reason_code < 0)
+ goto out_err;
+ if (reason_code > 0)
+ goto decline_rdma;
+
+ /* tbd in follow-on patch: more steps to setup RDMA communcication,
+ * rtoken_handling, modify_qp
+ */
+
+out_connected:
+ sk_refcnt_debug_inc(newsmcsk);
+ newsmcsk->sk_state = SMC_ACTIVE;
+enqueue:
+ lock_sock(&lsmc->sk);
+ if (lsmc->sk.sk_state == SMC_LISTEN) {
+ smc_accept_enqueue(&lsmc->sk, newsmcsk);
+ } else { /* no longer listening */
+ smc_close_non_accepted(newsmcsk);
+ }
+ release_sock(&lsmc->sk);
+
+ /* Wake up accept */
+ lsmc->sk.sk_data_ready(&lsmc->sk);
+ sock_put(&lsmc->sk); /* sock_hold in smc_tcp_listen_work */
+ return;
+
+decline_rdma:
+ /* RDMA setup failed, switch back to TCP */
+ new_smc->use_fallback = 1;
+ if (reason_code && (reason_code != SMC_CLC_DECL_REPLY)) {
+ rc = smc_clc_send_decline(new_smc, reason_code, 0);
+ if (rc < sizeof(struct smc_clc_msg_decline))
+ goto out_err;
+ }
+ goto out_connected;
+
+out_err:
+ newsmcsk->sk_state = SMC_CLOSED;
+ goto enqueue; /* queue new sock with sk_err set */
+}
+
+static void smc_tcp_listen_work(struct work_struct *work)
+{
+ struct smc_sock *lsmc = container_of(work, struct smc_sock,
+ tcp_listen_work);
+ struct smc_sock *new_smc;
+ int rc = 0;
+
+ lock_sock(&lsmc->sk);
+ while (lsmc->sk.sk_state == SMC_LISTEN) {
+ rc = smc_clcsock_accept(lsmc, &new_smc);
+ if (rc)
+ goto out;
+ if (!new_smc)
+ continue;
+
+ new_smc->listen_smc = lsmc;
+ new_smc->use_fallback = 0; /* assume rdma capability first */
+ sock_hold(&lsmc->sk); /* sock_put in smc_listen_work */
+ INIT_WORK(&new_smc->smc_listen_work, smc_listen_work);
+ smc_copy_sock_settings_to_smc(new_smc);
+ schedule_work(&new_smc->smc_listen_work);
+ }
+
+out:
+ release_sock(&lsmc->sk);
+ lsmc->sk.sk_data_ready(&lsmc->sk); /* no more listening, wake accept */
+}
+
static int smc_listen(struct socket *sock, int backlog)
{
struct sock *sk = sock->sk;
@@ -289,6 +650,8 @@ static int smc_listen(struct socket *sock, int backlog)
sk->sk_max_ack_backlog = backlog;
sk->sk_ack_backlog = 0;
sk->sk_state = SMC_LISTEN;
+ INIT_WORK(&smc->tcp_listen_work, smc_tcp_listen_work);
+ schedule_work(&smc->tcp_listen_work);

out:
release_sock(sk);
@@ -298,10 +661,11 @@ out:
static int smc_accept(struct socket *sock, struct socket *new_sock,
int flags)
{
- struct smc_sock *new_smc;
- struct sock *sk = sock->sk;
+ struct sock *sk = sock->sk, *nsk;
+ DECLARE_WAITQUEUE(wait, current);
struct smc_sock *lsmc;
- int rc;
+ long timeo;
+ int rc = 0;

lsmc = smc_sk(sk);
lock_sock(sk);
@@ -311,18 +675,30 @@ static int smc_accept(struct socket *sock, struct socket *new_sock,
goto out;
}

- rc = smc_clcsock_accept(lsmc, &new_smc);
- if (rc)
- goto out;
- sock_graft(&new_smc->sk, new_sock);
- new_smc->sk.sk_state = SMC_ACTIVE;
-
- smc_copy_sock_settings_to_smc(new_smc);
+ /* Wait for an incoming connection */
+ timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
+ add_wait_queue_exclusive(sk_sleep(sk), &wait);
+ while (!(nsk = smc_accept_dequeue(sk, new_sock))) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (!timeo) {
+ rc = -EAGAIN;
+ break;
+ }
+ release_sock(sk);
+ timeo = schedule_timeout(timeo);
+ /* wakeup by sk_data_ready in smc_listen_work() */
+ sched_annotate_sleep();
+ lock_sock(sk);
+ if (signal_pending(current)) {
+ rc = sock_intr_errno(timeo);
+ break;
+ }
+ }
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(sk_sleep(sk), &wait);

- /* always use TCP fallback as transport mechanism for now;
- * This will change once RDMA transport is implemented
- */
- new_smc->use_fallback = 1;
+ if (!rc)
+ rc = sock_error(nsk);

out:
release_sock(sk);
@@ -382,29 +758,61 @@ out:
return rc;
}

+static unsigned int smc_accept_poll(struct sock *parent)
+{
+ struct smc_sock *isk;
+ struct sock *sk;
+
+ lock_sock(parent);
+ list_for_each_entry(isk, &smc_sk(parent)->accept_q, accept_q) {
+ sk = (struct sock *)isk;
+
+ if (sk->sk_state == SMC_ACTIVE) {
+ release_sock(parent);
+ return POLLIN | POLLRDNORM;
+ }
+ }
+ release_sock(parent);
+
+ return 0;
+}
+
static unsigned int smc_poll(struct file *file, struct socket *sock,
poll_table *wait)
{
struct sock *sk = sock->sk;
unsigned int mask = 0;
struct smc_sock *smc;
+ int rc;

smc = smc_sk(sock->sk);
- if ((sk->sk_state == SMC_INIT) || (sk->sk_state == SMC_LISTEN) ||
- smc->use_fallback) {
+ if ((sk->sk_state == SMC_INIT) || smc->use_fallback) {
+ /* delegate to CLC child sock */
mask = smc->clcsock->ops->poll(file, smc->clcsock, wait);
/* if non-blocking connect finished ... */
lock_sock(sk);
if ((sk->sk_state == SMC_INIT) && (mask & POLLOUT)) {
- sk->sk_state = SMC_ACTIVE;
- /* always use TCP fallback as transport mechanism;
- * This will change once RDMA transport is implemented
- */
- smc->use_fallback = 1;
+ sk->sk_err = smc->clcsock->sk->sk_err;
+ if (sk->sk_err) {
+ mask |= POLLERR;
+ } else {
+ rc = smc_connect_rdma(smc);
+ if (rc < 0)
+ mask |= POLLERR;
+ else
+ /* success cases including fallback */
+ mask |= POLLOUT | POLLWRNORM;
+ }
}
release_sock(sk);
} else {
- mask = sock_no_poll(file, sock, wait);
+ sock_poll_wait(file, sk_sleep(sk), wait);
+ if (sk->sk_state == SMC_LISTEN)
+ /* woken up by sk_data_ready in smc_listen_work() */
+ mask |= smc_accept_poll(sk);
+ if (sk->sk_err)
+ mask |= POLLERR;
+ /* for now - to be enhanced in follow-on patch */
}

return mask;
@@ -571,6 +979,7 @@ static int smc_create(struct net *net, struct socket *sock, int protocol,

/* create internal TCP socket for CLC handshake and fallback */
smc = smc_sk(sk);
+ smc->use_fallback = 0; /* assume rdma capability first */
rc = sock_create_kern(net, PF_INET, SOCK_STREAM,
IPPROTO_TCP, &smc->clcsock);
if (rc)
diff --git a/net/smc/smc.h b/net/smc/smc.h
index a882f64..707e4f8 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -26,7 +26,14 @@ enum smc_state { /* possible states of an SMC socket */
struct smc_sock { /* smc sock container */
struct sock sk;
struct socket *clcsock; /* internal tcp socket */
- u8 use_fallback : 1; /* fallback to tcp */
+ struct sockaddr *addr; /* inet connect address */
+ struct smc_sock *listen_smc; /* listen parent */
+ struct work_struct tcp_listen_work;/* handle tcp socket accepts */
+ struct work_struct smc_listen_work;/* prepare new accept socket */
+ struct list_head accept_q; /* sockets to be accepted */
+ spinlock_t accept_q_lock; /* protects accept_q */
+ u8 use_fallback : 1, /* fallback to tcp */
+ clc_started : 1;/* smc_connect_rdma ran */
};

static inline struct smc_sock *smc_sk(const struct sock *sk)
@@ -38,4 +45,19 @@ static inline struct smc_sock *smc_sk(const struct sock *sk)

extern u8 local_systemid[SMC_SYSTEMID_LEN]; /* unique system identifier */

+#ifdef CONFIG_XFRM
+static inline bool using_ipsec(struct smc_sock *smc)
+{
+ return (smc->clcsock->sk->sk_policy[0] ||
+ smc->clcsock->sk->sk_policy[1]) ? 1 : 0;
+}
+#else
+static inline bool using_ipsec(struct smc_sock *smc)
+{
+ return 0;
+}
+#endif
+
+int smc_netinfo_by_tcpsk(struct socket *, __be32 *, u8 *);
+
#endif /* _SMC_H */
diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
new file mode 100644
index 0000000..cbc02a8
--- /dev/null
+++ b/net/smc/smc_clc.c
@@ -0,0 +1,251 @@
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ * CLC (connection layer control) handshake over initial TCP socket to
+ * prepare for RDMA traffic
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
+ */
+
+#include <net/sock.h>
+#include <net/tcp.h>
+
+#include "smc.h"
+#include "smc_clc.h"
+#include "smc_ib.h"
+
+/* Wait for data on the tcp-socket, analyze received data
+ * Returns:
+ * 0 if success and it was not a decline that we received.
+ * SMC_CLC_DECL_REPLY if decline received for fallback w/o another decl send.
+ * clcsock error, -EINTR, -ECONNRESET, -EPROTO otherwise.
+ */
+int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
+ u8 expected_type)
+{
+ struct sock *clc_sk = smc->clcsock->sk;
+ struct smc_clc_msg_hdr *clcm = buf;
+ struct msghdr msg = {NULL, 0};
+ int reason_code = 0;
+ DEFINE_WAIT(wait);
+ struct kvec vec;
+ int len, datlen;
+ int krflags;
+
+ /* peek the first few bytes to determine length of data to receive
+ * so we don't consume any subsequent CLC message or payload data
+ * in the TCP byte stream
+ */
+ vec.iov_base = buf;
+ vec.iov_len = buflen;
+ krflags = MSG_PEEK | MSG_WAITALL;
+ smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
+ len = kernel_recvmsg(smc->clcsock, &msg, &vec, 1,
+ sizeof(struct smc_clc_msg_hdr), krflags);
+ if (signal_pending(current)) {
+ reason_code = -EINTR;
+ clc_sk->sk_err = EINTR;
+ smc->sk.sk_err = EINTR;
+ goto out;
+ }
+ if (clc_sk->sk_err) {
+ reason_code = -clc_sk->sk_err;
+ smc->sk.sk_err = clc_sk->sk_err;
+ goto out;
+ }
+ if (!len) { /* peer has performed orderly shutdown */
+ smc->sk.sk_err = ECONNRESET;
+ reason_code = -ECONNRESET;
+ goto out;
+ }
+ if (len < 0) {
+ smc->sk.sk_err = -len;
+ reason_code = len;
+ goto out;
+ }
+ datlen = ntohs(clcm->length);
+ if ((len < sizeof(struct smc_clc_msg_hdr)) ||
+ (datlen < sizeof(struct smc_clc_msg_decline)) ||
+ memcmp(clcm->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) ||
+ ((clcm->type != SMC_CLC_DECLINE) &&
+ (clcm->type != expected_type))) {
+ smc->sk.sk_err = EPROTO;
+ reason_code = -EPROTO;
+ goto out;
+ }
+
+ /* receive the complete CLC message */
+ vec.iov_base = buf;
+ vec.iov_len = buflen;
+ memset(&msg, 0, sizeof(struct msghdr));
+ krflags = MSG_WAITALL;
+ smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
+ len = kernel_recvmsg(smc->clcsock, &msg, &vec, 1, datlen, krflags);
+ if (len < datlen) {
+ smc->sk.sk_err = EPROTO;
+ reason_code = -EPROTO;
+ goto out;
+ }
+ if (clcm->type == SMC_CLC_DECLINE)
+ reason_code = SMC_CLC_DECL_REPLY;
+out:
+ return reason_code;
+}
+
+/* send CLC DECLINE message across internal TCP socket */
+int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info,
+ u8 out_of_sync)
+{
+ struct smc_clc_msg_decline dclc;
+ struct msghdr msg;
+ struct kvec vec;
+ int len;
+
+ memset(&dclc, 0, sizeof(dclc));
+ memcpy(dclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+ dclc.hdr.type = SMC_CLC_DECLINE;
+ dclc.hdr.length = htons(sizeof(struct smc_clc_msg_decline));
+ dclc.hdr.version = SMC_CLC_V1;
+ dclc.hdr.flag = out_of_sync ? 1 : 0;
+ memcpy(dclc.id_for_peer, local_systemid, sizeof(local_systemid));
+ dclc.peer_diagnosis = htonl(peer_diag_info);
+ memcpy(dclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+
+ memset(&msg, 0, sizeof(msg));
+ vec.iov_base = &dclc;
+ vec.iov_len = sizeof(struct smc_clc_msg_decline);
+ len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
+ sizeof(struct smc_clc_msg_decline));
+ if (len < sizeof(struct smc_clc_msg_decline))
+ smc->sk.sk_err = EPROTO;
+ if (len < 0)
+ smc->sk.sk_err = -len;
+ return len;
+}
+
+/* send CLC PROPOSAL message across internal TCP socket */
+int smc_clc_send_proposal(struct smc_sock *smc,
+ struct smc_ib_device *smcibdev,
+ u8 ibport)
+{
+ struct smc_clc_msg_proposal pclc;
+ int reason_code = 0;
+ struct msghdr msg;
+ struct kvec vec;
+ int len, rc;
+
+ /* send SMC Proposal CLC message */
+ memset(&pclc, 0, sizeof(pclc));
+ memcpy(pclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+ pclc.hdr.type = SMC_CLC_PROPOSAL;
+ pclc.hdr.length = htons(sizeof(pclc));
+ pclc.hdr.version = SMC_CLC_V1; /* SMC version */
+ memcpy(pclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
+ memcpy(&pclc.lcl.gid, &smcibdev->gid[ibport - 1], SMC_GID_SIZE);
+ memcpy(&pclc.lcl.mac, &smcibdev->mac[ibport - 1],
+ sizeof(smcibdev->mac[ibport - 1]));
+
+ /* determine subnet and mask from internal TCP socket */
+ rc = smc_netinfo_by_tcpsk(smc->clcsock, &pclc.outgoing_subnet,
+ &pclc.prefix_len);
+ if (rc)
+ return SMC_CLC_DECL_CNFERR; /* configuration error */
+ memcpy(pclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+ memset(&msg, 0, sizeof(msg));
+ vec.iov_base = &pclc;
+ vec.iov_len = sizeof(pclc);
+ /* due to the few bytes needed for clc-handshake this cannot block */
+ len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1, sizeof(pclc));
+ if (len < sizeof(pclc)) {
+ if (len >= 0) {
+ reason_code = -ENETUNREACH;
+ smc->sk.sk_err = -reason_code;
+ } else {
+ smc->sk.sk_err = smc->clcsock->sk->sk_err;
+ reason_code = -smc->sk.sk_err;
+ }
+ }
+
+ return reason_code;
+}
+
+/* send CLC CONFIRM message across internal TCP socket */
+int smc_clc_send_confirm(struct smc_sock *smc)
+{
+ struct smc_clc_msg_accept_confirm cclc;
+ int reason_code = 0;
+ struct msghdr msg;
+ struct kvec vec;
+ int len;
+
+ /* send SMC Confirm CLC msg */
+ memset(&cclc, 0, sizeof(cclc));
+ memcpy(cclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+ cclc.hdr.type = SMC_CLC_CONFIRM;
+ cclc.hdr.length = htons(sizeof(cclc));
+ cclc.hdr.version = SMC_CLC_V1; /* SMC version */
+ memcpy(cclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
+
+ /* tbd in follow-on patch: fill in link-related values */
+
+ /* tbd in follow-on patch: fill in rmb-related values */
+
+ cclc.conn_idx = 1; /* for now: 1 RMB = 1 RMBE */
+
+ memcpy(cclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+
+ memset(&msg, 0, sizeof(msg));
+ vec.iov_base = &cclc;
+ vec.iov_len = sizeof(cclc);
+ len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1, sizeof(cclc));
+ if (len < sizeof(cclc)) {
+ if (len >= 0) {
+ reason_code = -ENETUNREACH;
+ smc->sk.sk_err = -reason_code;
+ } else {
+ smc->sk.sk_err = smc->clcsock->sk->sk_err;
+ reason_code = -smc->sk.sk_err;
+ }
+ }
+ return reason_code;
+}
+
+/* send CLC ACCEPT message across internal TCP socket */
+int smc_clc_send_accept(struct smc_sock *new_smc)
+{
+ struct smc_clc_msg_accept_confirm aclc;
+ struct msghdr msg;
+ struct kvec vec;
+ int rc = 0;
+ int len;
+
+ memset(&aclc, 0, sizeof(aclc));
+ memcpy(aclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+ aclc.hdr.type = SMC_CLC_ACCEPT;
+ aclc.hdr.length = htons(sizeof(aclc));
+ aclc.hdr.version = SMC_CLC_V1; /* SMC version */
+ memcpy(aclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
+
+ /* tbd in follow-on patch: fill in link-related values */
+
+ /* tbd in follow-on patch: fill in rmb-related values */
+
+ aclc.conn_idx = 1; /* as long as 1 RMB = 1 RMBE */
+ memcpy(aclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+
+ memset(&msg, 0, sizeof(msg));
+ vec.iov_base = &aclc;
+ vec.iov_len = sizeof(aclc);
+ len = kernel_sendmsg(new_smc->clcsock, &msg, &vec, 1, sizeof(aclc));
+ if (len < sizeof(aclc)) {
+ if (len >= 0)
+ new_smc->sk.sk_err = EPROTO;
+ else
+ new_smc->sk.sk_err = new_smc->clcsock->sk->sk_err;
+ rc = sock_error(&new_smc->sk);
+ }
+
+ return rc;
+}
diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
new file mode 100644
index 0000000..565c62a
--- /dev/null
+++ b/net/smc/smc_clc.h
@@ -0,0 +1,111 @@
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ * CLC (connection layer control) handshake over initial TCP socket to
+ * prepare for RDMA traffic
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
+ */
+
+#ifndef _SMC_CLC_H
+#define _SMC_CLC_H
+
+#include <rdma/ib_verbs.h>
+
+#include "smc.h"
+
+#define SMC_CLC_PROPOSAL 0x01
+#define SMC_CLC_ACCEPT 0x02
+#define SMC_CLC_CONFIRM 0x03
+#define SMC_CLC_DECLINE 0x04
+
+/* eye catcher "SMCR" EBCDIC for CLC messages */
+static const char SMC_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xd9'};
+
+#define SMC_CLC_V1 0x1 /* SMC version */
+#define CLC_WAIT_TIME (6 * HZ) /* max. wait time on clcsock */
+#define SMC_CLC_DECL_MEM 0x01010000 /* insufficient memory resources */
+#define SMC_CLC_DECL_TIMEOUT 0x02000000 /* timeout */
+#define SMC_CLC_DECL_CNFERR 0x03000000 /* configuration error */
+#define SMC_CLC_DECL_IPSEC 0x03030000 /* IPsec usage */
+#define SMC_CLC_DECL_SYNCERR 0x04000000 /* synchronization error */
+#define SMC_CLC_DECL_REPLY 0x06000000 /* reply to a received decline */
+#define SMC_CLC_DECL_INTERR 0x99990000 /* internal error */
+
+struct smc_clc_msg_hdr { /* header1 of clc messages */
+ u8 eyecatcher[4]; /* eye catcher */
+ u8 type; /* proposal / accept / confirm / decline */
+ __be16 length;
+#if defined(__BIG_ENDIAN_BITFIELD)
+ u8 version : 4,
+ flag : 1,
+ rsvd : 3;
+#elif defined(__LITTLE_ENDIAN_BITFIELD)
+ u8 rsvd : 3,
+ flag : 1,
+ version : 4;
+#endif
+} __packed;
+
+struct smc_clc_msg_trail { /* trailer of clc messages */
+ u8 eyecatcher[4];
+} __packed;
+
+struct smc_clc_msg_local { /* header2 of clc messages */
+ u8 id_for_peer[SMC_SYSTEMID_LEN]; /* unique system id */
+ union ib_gid gid; /* gid of ib_device port */
+ u8 mac[6]; /* mac of ib_device port */
+} __packed;
+
+struct smc_clc_msg_proposal { /* clc proposal message */
+ struct smc_clc_msg_hdr hdr;
+ struct smc_clc_msg_local lcl;
+ __be16 iparea_offset; /* offset to IP address information area */
+ __be32 outgoing_subnet; /* subnet mask */
+ u8 prefix_len; /* number of significant bits in mask */
+ u8 reserved[2];
+ u8 ipv6_prefixes_cnt; /* number of IPv6 prefixes in prefix array */
+ struct smc_clc_msg_trail trl; /* eye catcher "SMCR" EBCDIC */
+} __packed;
+
+struct smc_clc_msg_accept_confirm { /* clc accept / confirm message */
+ struct smc_clc_msg_hdr hdr;
+ struct smc_clc_msg_local lcl;
+ u8 qpn[3]; /* QP number */
+ __be32 rmb_rkey; /* RMB rkey */
+ u8 conn_idx; /* Connection index, which RMBE in RMB */
+ __be32 rmbe_alert_token;/* unique connection id */
+#if defined(__BIG_ENDIAN_BITFIELD)
+ u8 rmbe_size : 4, /* RMBE buf size (compressed notation) */
+ qp_mtu : 4; /* QP mtu */
+#elif defined(__LITTLE_ENDIAN_BITFIELD)
+ u8 qp_mtu : 4,
+ rmbe_size : 4;
+#endif
+ u8 reserved;
+ __be64 rmb_dma_addr; /* RMB virtual address */
+ u8 reserved2;
+ u8 psn[3]; /* initial packet sequence number */
+ struct smc_clc_msg_trail trl; /* eye catcher "SMCR" EBCDIC */
+} __packed;
+
+struct smc_clc_msg_decline { /* clc decline message */
+ struct smc_clc_msg_hdr hdr;
+ u8 id_for_peer[SMC_SYSTEMID_LEN]; /* sender peer_id */
+ __be32 peer_diagnosis; /* diagnosis information */
+ u8 reserved2[4];
+ struct smc_clc_msg_trail trl; /* eye catcher "SMCR" EBCDIC */
+} __packed;
+
+struct smc_sock;
+struct smc_ib_device;
+
+int smc_clc_wait_msg(struct smc_sock *, void *, int, u8);
+int smc_clc_send_decline(struct smc_sock *, u32, u8);
+int smc_clc_send_proposal(struct smc_sock *, struct smc_ib_device *, u8);
+int smc_clc_send_confirm(struct smc_sock *);
+int smc_clc_send_accept(struct smc_sock *);
+
+#endif
--
2.8.4