[PATCH v9 3/6] virtio-user: add vhost user adapter layer

[Jianfeng Tan <jianfeng.tan@intel.com>]

This patch is to provide vhost adapter layer implementations. Instead
of relying on a hypervisor to translate between device emulation and
vhost backend, here we directly talk with vhost backend through the
vhost file.

Here three main APIs are provided to upper layer (device emulation):
  - vhost_user_setup(), to set up vhost user backend;
  - vhost_user_sock(), to talk with vhost user backend.

  ----------------------
  | ------------------ |
  | | virtio driver  | |
  | ------------------ |
  |         |          |
  | ------------------ | ------>  virtio-user PMD
  | | device emulate | |
  | |                | |
  | | vhost adapter  |-|----> (vhost_user.c)
  | ------------------ |
  ----------------------
            |
            | -------------- --> (vhost-user protocol)
            |
   ------------------
   | vhost backend  |
   ------------------

Signed-off-by: Huawei Xie <huawei.xie@intel.com>
Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
---
 config/common_linuxapp                      |   1 +
 drivers/net/virtio/Makefile                 |   4 +
 drivers/net/virtio/virtio_user/vhost.h      | 141 ++++++++++
 drivers/net/virtio/virtio_user/vhost_user.c | 404 ++++++++++++++++++++++++++++
 4 files changed, 550 insertions(+)
 create mode 100644 drivers/net/virtio/virtio_user/vhost.h
 create mode 100644 drivers/net/virtio/virtio_user/vhost_user.c

diff --git a/config/common_linuxapp b/config/common_linuxapp
index 7e698e2..2483dfa 100644
--- a/config/common_linuxapp
+++ b/config/common_linuxapp
@@ -43,3 +43,4 @@ CONFIG_RTE_LIBRTE_VHOST=y
 CONFIG_RTE_LIBRTE_PMD_VHOST=y
 CONFIG_RTE_LIBRTE_PMD_AF_PACKET=y
 CONFIG_RTE_LIBRTE_POWER=y
+CONFIG_RTE_VIRTIO_USER=y
diff --git a/drivers/net/virtio/Makefile b/drivers/net/virtio/Makefile
index ef84f60..c2ed0fa 100644
--- a/drivers/net/virtio/Makefile
+++ b/drivers/net/virtio/Makefile
@@ -55,6 +55,10 @@ ifeq ($(findstring RTE_MACHINE_CPUFLAG_SSSE3,$(CFLAGS)),RTE_MACHINE_CPUFLAG_SSSE
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_rxtx_simple.c
 endif
 
+ifeq ($(CONFIG_RTE_VIRTIO_USER),y)
+SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_user/vhost_user.c
+endif
+
 # this lib depends upon:
 DEPDIRS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += lib/librte_eal lib/librte_ether
 DEPDIRS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += lib/librte_mempool lib/librte_mbuf
diff --git a/drivers/net/virtio/virtio_user/vhost.h b/drivers/net/virtio/virtio_user/vhost.h
new file mode 100644
index 0000000..4e04ede
--- /dev/null
+++ b/drivers/net/virtio/virtio_user/vhost.h
@@ -0,0 +1,141 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _VHOST_NET_USER_H
+#define _VHOST_NET_USER_H
+
+#include <stdint.h>
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#include "../virtio_pci.h"
+#include "../virtio_logs.h"
+#include "../virtqueue.h"
+
+#define VHOST_MEMORY_MAX_NREGIONS 8
+
+struct vhost_vring_state {
+	unsigned int index;
+	unsigned int num;
+};
+
+struct vhost_vring_file {
+	unsigned int index;
+	int fd;
+};
+
+struct vhost_vring_addr {
+	unsigned int index;
+	/* Option flags. */
+	unsigned int flags;
+	/* Flag values: */
+	/* Whether log address is valid. If set enables logging. */
+#define VHOST_VRING_F_LOG 0
+
+	/* Start of array of descriptors (virtually contiguous) */
+	uint64_t desc_user_addr;
+	/* Used structure address. Must be 32 bit aligned */
+	uint64_t used_user_addr;
+	/* Available structure address. Must be 16 bit aligned */
+	uint64_t avail_user_addr;
+	/* Logging support. */
+	/* Log writes to used structure, at offset calculated from specified
+	 * address. Address must be 32 bit aligned.
+	 */
+	uint64_t log_guest_addr;
+};
+
+enum vhost_user_request {
+	VHOST_USER_NONE = 0,
+	VHOST_USER_GET_FEATURES = 1,
+	VHOST_USER_SET_FEATURES = 2,
+	VHOST_USER_SET_OWNER = 3,
+	VHOST_USER_RESET_OWNER = 4,
+	VHOST_USER_SET_MEM_TABLE = 5,
+	VHOST_USER_SET_LOG_BASE = 6,
+	VHOST_USER_SET_LOG_FD = 7,
+	VHOST_USER_SET_VRING_NUM = 8,
+	VHOST_USER_SET_VRING_ADDR = 9,
+	VHOST_USER_SET_VRING_BASE = 10,
+	VHOST_USER_GET_VRING_BASE = 11,
+	VHOST_USER_SET_VRING_KICK = 12,
+	VHOST_USER_SET_VRING_CALL = 13,
+	VHOST_USER_SET_VRING_ERR = 14,
+	VHOST_USER_GET_PROTOCOL_FEATURES = 15,
+	VHOST_USER_SET_PROTOCOL_FEATURES = 16,
+	VHOST_USER_GET_QUEUE_NUM = 17,
+	VHOST_USER_SET_VRING_ENABLE = 18,
+	VHOST_USER_MAX
+};
+
+struct vhost_memory_region {
+	uint64_t guest_phys_addr;
+	uint64_t memory_size; /* bytes */
+	uint64_t userspace_addr;
+	uint64_t mmap_offset;
+};
+
+struct vhost_memory {
+	uint32_t nregions;
+	uint32_t padding;
+	struct vhost_memory_region regions[VHOST_MEMORY_MAX_NREGIONS];
+};
+
+struct vhost_user_msg {
+	enum vhost_user_request request;
+
+#define VHOST_USER_VERSION_MASK     0x3
+#define VHOST_USER_REPLY_MASK       (0x1 << 2)
+	uint32_t flags;
+	uint32_t size; /* the following payload size */
+	union {
+#define VHOST_USER_VRING_IDX_MASK   0xff
+#define VHOST_USER_VRING_NOFD_MASK  (0x1 << 8)
+		uint64_t u64;
+		struct vhost_vring_state state;
+		struct vhost_vring_addr addr;
+		struct vhost_memory memory;
+	} payload;
+	int fds[VHOST_MEMORY_MAX_NREGIONS];
+} __attribute((packed));
+
+#define VHOST_USER_HDR_SIZE offsetof(struct vhost_user_msg, payload.u64)
+#define VHOST_USER_PAYLOAD_SIZE \
+	(sizeof(struct vhost_user_msg) - VHOST_USER_HDR_SIZE)
+
+/* The version of the protocol we support */
+#define VHOST_USER_VERSION    0x1
+
+int vhost_user_sock(int vhostfd, uint64_t req, void *arg);
+int vhost_user_setup(const char *path);
+#endif
diff --git a/drivers/net/virtio/virtio_user/vhost_user.c b/drivers/net/virtio/virtio_user/vhost_user.c
new file mode 100644
index 0000000..47bbf74
--- /dev/null
+++ b/drivers/net/virtio/virtio_user/vhost_user.c
@@ -0,0 +1,404 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/un.h>
+#include <string.h>
+#include <errno.h>
+
+#include "vhost.h"
+
+static int
+vhost_user_write(int fd, void *buf, int len, int *fds, int fd_num)
+{
+	int r;
+	struct msghdr msgh;
+	struct iovec iov;
+	size_t fd_size = fd_num * sizeof(int);
+	char control[CMSG_SPACE(fd_size)];
+	struct cmsghdr *cmsg;
+
+	memset(&msgh, 0, sizeof(msgh));
+	memset(control, 0, sizeof(control));
+
+	iov.iov_base = (uint8_t *)buf;
+	iov.iov_len = len;
+
+	msgh.msg_iov = &iov;
+	msgh.msg_iovlen = 1;
+	msgh.msg_control = control;
+	msgh.msg_controllen = sizeof(control);
+
+	cmsg = CMSG_FIRSTHDR(&msgh);
+	cmsg->cmsg_len = CMSG_LEN(fd_size);
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+	memcpy(CMSG_DATA(cmsg), fds, fd_size);
+
+	do {
+		r = sendmsg(fd, &msgh, 0);
+	} while (r < 0 && errno == EINTR);
+
+	return r;
+}
+
+static int
+vhost_user_read(int fd, struct vhost_user_msg *msg)
+{
+	uint32_t valid_flags = VHOST_USER_REPLY_MASK | VHOST_USER_VERSION;
+	int ret, sz_hdr = VHOST_USER_HDR_SIZE, sz_payload;
+
+	ret = recv(fd, (void *)msg, sz_hdr, 0);
+	if (ret < sz_hdr) {
+		PMD_DRV_LOG(ERR, "Failed to recv msg hdr: %d instead of %d.",
+			    ret, sz_hdr);
+		goto fail;
+	}
+
+	/* validate msg flags */
+	if (msg->flags != (valid_flags)) {
+		PMD_DRV_LOG(ERR, "Failed to recv msg: flags %x instead of %x.",
+			    msg->flags, valid_flags);
+		goto fail;
+	}
+
+	sz_payload = msg->size;
+	if (sz_payload) {
+		ret = recv(fd, (void *)((char *)msg + sz_hdr), sz_payload, 0);
+		if (ret < sz_payload) {
+			PMD_DRV_LOG(ERR, "Failed to recv msg payload: %d instead of %d.",
+				    ret, msg->size);
+			goto fail;
+		}
+	}
+
+	return 0;
+
+fail:
+	return -1;
+}
+
+struct hugepage_file_info {
+	uint64_t addr;            /**< virtual addr */
+	size_t   size;            /**< the file size */
+	char     path[PATH_MAX];  /**< path to backing file */
+};
+
+/* Two possible options:
+ * 1. Match HUGEPAGE_INFO_FMT to find the file storing struct hugepage_file
+ * array. This is simple but cannot be used in secondary process because
+ * secondary process will close and munmap that file.
+ * 2. Match HUGEFILE_FMT to find hugepage files directly.
+ *
+ * We choose option 2.
+ */
+static int
+get_hugepage_file_info(struct hugepage_file_info huges[], int max)
+{
+	int idx;
+	FILE *f;
+	char buf[BUFSIZ], *tmp, *tail;
+	char *str_underline, *str_start;
+	int huge_index;
+	uint64_t v_start, v_end;
+
+	f = fopen("/proc/self/maps", "r");
+	if (!f) {
+		PMD_DRV_LOG(ERR, "cannot open /proc/self/maps");
+		return -1;
+	}
+
+	idx = 0;
+	while (fgets(buf, sizeof(buf), f) != NULL) {
+		if (sscanf(buf, "%" PRIx64 "-%" PRIx64, &v_start, &v_end) < 2) {
+			PMD_DRV_LOG(ERR, "Failed to parse address");
+			goto error;
+		}
+
+		tmp = strchr(buf, ' ') + 1; /** skip address */
+		tmp = strchr(tmp, ' ') + 1; /** skip perm */
+		tmp = strchr(tmp, ' ') + 1; /** skip offset */
+		tmp = strchr(tmp, ' ') + 1; /** skip dev */
+		tmp = strchr(tmp, ' ') + 1; /** skip inode */
+		while (*tmp == ' ')         /** skip spaces */
+			tmp++;
+		tail = strrchr(tmp, '\n');  /** remove newline if exists */
+		if (tail)
+			*tail = '\0';
+
+		/* Match HUGEFILE_FMT, aka "%s/%smap_%d",
+		 * which is defined in eal_filesystem.h
+		 */
+		str_underline = strrchr(tmp, '_');
+		if (!str_underline)
+			continue;
+
+		str_start = str_underline - strlen("map");
+		if (str_start < tmp)
+			continue;
+
+		if (sscanf(str_start, "map_%d", &huge_index) != 1)
+			continue;
+
+		if (idx >= max) {
+			PMD_DRV_LOG(ERR, "Exceed maximum of %d", max);
+			goto error;
+		}
+		huges[idx].addr = v_start;
+		huges[idx].size = v_end - v_start;
+		strcpy(huges[idx].path, tmp);
+		idx++;
+	}
+
+	fclose(f);
+	return idx;
+
+error:
+	fclose(f);
+	return -1;
+}
+
+static int
+prepare_vhost_memory_user(struct vhost_user_msg *msg, int fds[])
+{
+	int i, num;
+	struct hugepage_file_info huges[VHOST_MEMORY_MAX_NREGIONS];
+	struct vhost_memory_region *mr;
+
+	num = get_hugepage_file_info(huges, VHOST_MEMORY_MAX_NREGIONS);
+	if (num < 0) {
+		PMD_INIT_LOG(ERR, "Failed to prepare memory for vhost-user");
+		return -1;
+	}
+
+	for (i = 0; i < num; ++i) {
+		mr = &msg->payload.memory.regions[i];
+		mr->guest_phys_addr = huges[i].addr; /* use vaddr! */
+		mr->userspace_addr = huges[i].addr;
+		mr->memory_size = huges[i].size;
+		mr->mmap_offset = 0;
+		fds[i] = open(huges[i].path, O_RDWR);
+	}
+
+	msg->payload.memory.nregions = num;
+	msg->payload.memory.padding = 0;
+
+	return 0;
+}
+
+static struct vhost_user_msg m;
+
+static const char * const vhost_msg_strings[] = {
+	[VHOST_USER_SET_OWNER] = "VHOST_USER_SET_OWNER",
+	[VHOST_USER_RESET_OWNER] = "VHOST_USER_RESET_OWNER",
+	[VHOST_USER_SET_FEATURES] = "VHOST_USER_SET_FEATURES",
+	[VHOST_USER_GET_FEATURES] = "VHOST_USER_GET_FEATURES",
+	[VHOST_USER_SET_VRING_CALL] = "VHOST_USER_SET_VRING_CALL",
+	[VHOST_USER_SET_VRING_NUM] = "VHOST_USER_SET_VRING_NUM",
+	[VHOST_USER_SET_VRING_BASE] = "VHOST_USER_SET_VRING_BASE",
+	[VHOST_USER_GET_VRING_BASE] = "VHOST_USER_GET_VRING_BASE",
+	[VHOST_USER_SET_VRING_ADDR] = "VHOST_USER_SET_VRING_ADDR",
+	[VHOST_USER_SET_VRING_KICK] = "VHOST_USER_SET_VRING_KICK",
+	[VHOST_USER_SET_MEM_TABLE] = "VHOST_USER_SET_MEM_TABLE",
+	NULL,
+};
+
+int
+vhost_user_sock(int vhostfd, uint64_t req, void *arg)
+{
+	struct vhost_user_msg msg;
+	struct vhost_vring_file *file = 0;
+	int need_reply = 0;
+	int fds[VHOST_MEMORY_MAX_NREGIONS];
+	int fd_num = 0;
+	int i, len;
+
+	RTE_SET_USED(m);
+	RTE_SET_USED(vhost_msg_strings);
+
+	PMD_DRV_LOG(INFO, "%s", vhost_msg_strings[req]);
+
+	msg.request = req;
+	msg.flags = VHOST_USER_VERSION;
+	msg.size = 0;
+
+	switch (req) {
+	case VHOST_USER_GET_FEATURES:
+		need_reply = 1;
+		break;
+
+	case VHOST_USER_SET_FEATURES:
+	case VHOST_USER_SET_LOG_BASE:
+		msg.payload.u64 = *((__u64 *)arg);
+		msg.size = sizeof(m.payload.u64);
+		break;
+
+	case VHOST_USER_SET_OWNER:
+	case VHOST_USER_RESET_OWNER:
+		break;
+
+	case VHOST_USER_SET_MEM_TABLE:
+		if (prepare_vhost_memory_user(&msg, fds) < 0)
+			return -1;
+		fd_num = msg.payload.memory.nregions;
+		msg.size = sizeof(m.payload.memory.nregions);
+		msg.size += sizeof(m.payload.memory.padding);
+		msg.size += fd_num * sizeof(struct vhost_memory_region);
+		break;
+
+	case VHOST_USER_SET_LOG_FD:
+		fds[fd_num++] = *((int *)arg);
+		break;
+
+	case VHOST_USER_SET_VRING_NUM:
+	case VHOST_USER_SET_VRING_BASE:
+		memcpy(&msg.payload.state, arg, sizeof(msg.payload.state));
+		msg.size = sizeof(m.payload.state);
+		break;
+
+	case VHOST_USER_GET_VRING_BASE:
+		memcpy(&msg.payload.state, arg, sizeof(msg.payload.state));
+		msg.size = sizeof(m.payload.state);
+		need_reply = 1;
+		break;
+
+	case VHOST_USER_SET_VRING_ADDR:
+		memcpy(&msg.payload.addr, arg, sizeof(msg.payload.addr));
+		msg.size = sizeof(m.payload.addr);
+		break;
+
+	case VHOST_USER_SET_VRING_KICK:
+	case VHOST_USER_SET_VRING_CALL:
+	case VHOST_USER_SET_VRING_ERR:
+		file = arg;
+		msg.payload.u64 = file->index & VHOST_USER_VRING_IDX_MASK;
+		msg.size = sizeof(m.payload.u64);
+		if (file->fd > 0)
+			fds[fd_num++] = file->fd;
+		else
+			msg.payload.u64 |= VHOST_USER_VRING_NOFD_MASK;
+		break;
+
+	default:
+		PMD_DRV_LOG(ERR, "trying to send unhandled msg type");
+		return -1;
+	}
+
+	len = VHOST_USER_HDR_SIZE + msg.size;
+	if (vhost_user_write(vhostfd, &msg, len, fds, fd_num) < 0) {
+		PMD_DRV_LOG(ERR, "%s failed: %s",
+			    vhost_msg_strings[req], strerror(errno));
+		return -1;
+	}
+
+	if (req == VHOST_USER_SET_MEM_TABLE)
+		for (i = 0; i < fd_num; ++i)
+			close(fds[i]);
+
+	if (need_reply) {
+		if (vhost_user_read(vhostfd, &msg) < 0) {
+			PMD_DRV_LOG(ERR, "Received msg failed: %s",
+				    strerror(errno));
+			return -1;
+		}
+
+		if (req != msg.request) {
+			PMD_DRV_LOG(ERR, "Received unexpected msg type");
+			return -1;
+		}
+
+		switch (req) {
+		case VHOST_USER_GET_FEATURES:
+			if (msg.size != sizeof(m.payload.u64)) {
+				PMD_DRV_LOG(ERR, "Received bad msg size");
+				return -1;
+			}
+			*((__u64 *)arg) = msg.payload.u64;
+			break;
+		case VHOST_USER_GET_VRING_BASE:
+			if (msg.size != sizeof(m.payload.state)) {
+				PMD_DRV_LOG(ERR, "Received bad msg size");
+				return -1;
+			}
+			memcpy(arg, &msg.payload.state,
+			       sizeof(struct vhost_vring_state));
+			break;
+		default:
+			PMD_DRV_LOG(ERR, "Received unexpected msg type");
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * Set up environment to talk with a vhost user backend.
+ * @param path
+ *   - The path to vhost user unix socket file.
+ *
+ * @return
+ *   - (-1) if fail to set up;
+ *   - (>=0) if successful, and it is the fd to vhostfd.
+ */
+int
+vhost_user_setup(const char *path)
+{
+	int fd;
+	int flag;
+	struct sockaddr_un un;
+
+	fd = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (fd < 0) {
+		PMD_DRV_LOG(ERR, "socket() error, %s", strerror(errno));
+		return -1;
+	}
+
+	flag = fcntl(fd, F_GETFD);
+	fcntl(fd, F_SETFD, flag | FD_CLOEXEC);
+
+	memset(&un, 0, sizeof(un));
+	un.sun_family = AF_UNIX;
+	snprintf(un.sun_path, sizeof(un.sun_path), "%s", path);
+	if (connect(fd, (struct sockaddr *)&un, sizeof(un)) < 0) {
+		PMD_DRV_LOG(ERR, "connect error, %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	return fd;
+}
-- 
2.1.4