[1/9] lib: introduce vfio-user library

diff --git a/MAINTAINERS b/MAINTAINERS
index eafe9f8c46..5fb4880758 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1540,6 +1540,10 @@  M: Nithin Dabilpuram <ndabilpuram@marvell.com>
 M: Pavan Nikhilesh <pbhagavatula@marvell.com>
 F: lib/librte_node/
 
+Vfio-user - EXPERIMENTAL
+M: Chenbo Xia <chenbo.xia@intel.com>
+M: Xiuchun Lu <xiuchun.lu@intel.com>
+F: lib/librte_vfio_user/
 
 Test Applications
 -----------------
diff --git a/lib/librte_vfio_user/meson.build b/lib/librte_vfio_user/meson.build
new file mode 100644
index 0000000000..0f6407b80f
--- /dev/null
+++ b/lib/librte_vfio_user/meson.build
@@ -0,0 +1,9 @@ 
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2020 Intel Corporation
+
+if not is_linux
+	build = false
+	reason = 'only supported on Linux'
+endif
+
+sources = files('vfio_user_base.c')
diff --git a/lib/librte_vfio_user/version.map b/lib/librte_vfio_user/version.map
new file mode 100644
index 0000000000..33c1b976f1
--- /dev/null
+++ b/lib/librte_vfio_user/version.map
@@ -0,0 +1,3 @@ 
+EXPERIMENTAL {
+	local: *;
+};
diff --git a/lib/librte_vfio_user/vfio_user_base.c b/lib/librte_vfio_user/vfio_user_base.c
new file mode 100644
index 0000000000..bbad553e0a
--- /dev/null
+++ b/lib/librte_vfio_user/vfio_user_base.c
@@ -0,0 +1,205 @@ 
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2020 Intel Corporation
+ */
+
+#include <unistd.h>
+#include <sys/socket.h>
+#include <string.h>
+
+#include "vfio_user_base.h"
+
+int vfio_user_log_level;
+
+const char *vfio_user_msg_str[VFIO_USER_MAX] = {
+	[VFIO_USER_NONE] = "VFIO_USER_NONE",
+	[VFIO_USER_VERSION] = "VFIO_USER_VERSION",
+};
+
+inline void vfio_user_close_msg_fds(VFIO_USER_MSG *msg)
+{
+	int i;
+
+	for (i = 0; i < msg->fd_num; i++)
+		close(msg->fds[i]);
+}
+
+int vfio_user_check_msg_fdnum(VFIO_USER_MSG *msg, int expected_fds)
+{
+	if (msg->fd_num == expected_fds)
+		return 0;
+
+	VFIO_USER_LOG(ERR, "Expect %d FDs for request %s, received %d\n",
+		expected_fds, vfio_user_msg_str[msg->cmd], msg->fd_num);
+
+	vfio_user_close_msg_fds(msg);
+
+	return -1;
+}
+
+static int vfio_user_recv_fd_msg(int sockfd, char *buf, int buflen, int *fds,
+	int max_fds, int *fd_num)
+{
+	struct iovec iov;
+	struct msghdr msgh;
+	char control[CMSG_SPACE(max_fds * sizeof(int))];
+	struct cmsghdr *cmsg;
+	int fd_sz, got_fds = 0;
+	int ret, i;
+
+	*fd_num = 0;
+
+	memset(&msgh, 0, sizeof(msgh));
+	iov.iov_base = buf;
+	iov.iov_len  = buflen;
+
+	msgh.msg_iov = &iov;
+	msgh.msg_iovlen = 1;
+	msgh.msg_control = control;
+	msgh.msg_controllen = sizeof(control);
+
+	ret = recvmsg(sockfd, &msgh, 0);
+	if (ret <= 0) {
+		if (ret)
+			VFIO_USER_LOG(DEBUG, "recvmsg failed\n");
+		return ret;
+	}
+
+	if (msgh.msg_flags & (MSG_TRUNC | MSG_CTRUNC)) {
+		VFIO_USER_LOG(ERR, "Message is truncated\n");
+		return -1;
+	}
+
+	for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL;
+		cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
+		if ((cmsg->cmsg_level == SOL_SOCKET) &&
+			(cmsg->cmsg_type == SCM_RIGHTS)) {
+			fd_sz = cmsg->cmsg_len - CMSG_LEN(0);
+			got_fds = fd_sz / sizeof(int);
+			if (got_fds >= max_fds) {
+				/* Invalid message, close fds */
+				int *close_fd = (int *)CMSG_DATA(cmsg);
+				for (i = 0; i < got_fds; i++) {
+					close_fd += i;
+					close(*close_fd);
+				}
+				VFIO_USER_LOG(ERR, "fd num exceeds max "
+					"in vfio-user msg\n");
+				return -1;
+			}
+			*fd_num = got_fds;
+			memcpy(fds, CMSG_DATA(cmsg), got_fds * sizeof(int));
+			break;
+		}
+	}
+
+	/* Make unused file descriptors invalid */
+	while (got_fds < max_fds)
+		fds[got_fds++] = -1;
+
+	return ret;
+}
+
+int vfio_user_recv_msg(int sockfd, VFIO_USER_MSG *msg)
+{
+	int ret;
+
+	ret = vfio_user_recv_fd_msg(sockfd, (char *)msg, VFIO_USER_MSG_HDR_SIZE,
+		msg->fds, VFIO_USER_MAX_FD, &msg->fd_num);
+	if (ret <= 0) {
+		return ret;
+	} else if (ret != VFIO_USER_MSG_HDR_SIZE) {
+		VFIO_USER_LOG(ERR, "Read unexpected header size\n");
+		ret = -1;
+		goto err;
+	}
+
+	if (msg->size > VFIO_USER_MSG_HDR_SIZE) {
+		if (msg->size > (sizeof(msg->payload) +
+			VFIO_USER_MSG_HDR_SIZE)) {
+			VFIO_USER_LOG(ERR, "Read invalid msg size: %d\n",
+				msg->size);
+			ret = -1;
+			goto err;
+		}
+
+		ret = read(sockfd, &msg->payload,
+			msg->size - VFIO_USER_MSG_HDR_SIZE);
+		if (ret <= 0)
+			goto err;
+		if (ret != (int)(msg->size - VFIO_USER_MSG_HDR_SIZE)) {
+			VFIO_USER_LOG(ERR, "Read payload failed\n");
+			ret = -1;
+			goto err;
+		}
+	}
+
+	return ret;
+err:
+	vfio_user_close_msg_fds(msg);
+	return ret;
+}
+
+static int
+vfio_user_send_fd_msg(int sockfd, char *buf, int buflen, int *fds, int fd_num)
+{
+
+	struct iovec iov;
+	struct msghdr msgh;
+	size_t fdsize = fd_num * sizeof(int);
+	char control[CMSG_SPACE(fdsize)];
+	struct cmsghdr *cmsg;
+	int ret;
+
+	memset(&msgh, 0, sizeof(msgh));
+	iov.iov_base = buf;
+	iov.iov_len = buflen;
+
+	msgh.msg_iov = &iov;
+	msgh.msg_iovlen = 1;
+
+	if (fds && fd_num > 0) {
+		msgh.msg_control = control;
+		msgh.msg_controllen = sizeof(control);
+		cmsg = CMSG_FIRSTHDR(&msgh);
+		cmsg->cmsg_len = CMSG_LEN(fdsize);
+		cmsg->cmsg_level = SOL_SOCKET;
+		cmsg->cmsg_type = SCM_RIGHTS;
+		memcpy(CMSG_DATA(cmsg), fds, fdsize);
+	} else {
+		msgh.msg_control = NULL;
+		msgh.msg_controllen = 0;
+	}
+
+	do {
+		ret = sendmsg(sockfd, &msgh, MSG_NOSIGNAL);
+	} while (ret < 0 && errno == EINTR);
+
+	if (ret < 0) {
+		VFIO_USER_LOG(ERR, "sendmsg error\n");
+		return ret;
+	}
+
+	return ret;
+}
+
+int vfio_user_send_msg(int sockfd, VFIO_USER_MSG *msg)
+{
+	if (!msg)
+		return 0;
+
+	return vfio_user_send_fd_msg(sockfd, (char *)msg,
+		msg->size, msg->fds, msg->fd_num);
+}
+
+int vfio_user_reply_msg(int sockfd, VFIO_USER_MSG *msg)
+{
+	if (!msg)
+		return 0;
+
+	msg->flags |= VFIO_USER_NEED_NO_RP;
+	msg->flags |= VFIO_USER_TYPE_REPLY;
+
+	return vfio_user_send_msg(sockfd, msg);
+}
+
+RTE_LOG_REGISTER(vfio_user_log_level, lib.vfio, INFO);
diff --git a/lib/librte_vfio_user/vfio_user_base.h b/lib/librte_vfio_user/vfio_user_base.h
new file mode 100644
index 0000000000..6db45b1819
--- /dev/null
+++ b/lib/librte_vfio_user/vfio_user_base.h
@@ -0,0 +1,65 @@ 
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2020 Intel Corporation
+ */
+
+#ifndef _VFIO_USER_BASE_H
+#define _VFIO_USER_BASE_H
+
+#include <rte_log.h>
+
+#define VFIO_USER_MAX_FD 1024
+#define VFIO_USER_MAX_VERSION_DATA 512
+
+extern int vfio_user_log_level;
+extern const char *vfio_user_msg_str[];
+
+#define VFIO_USER_LOG(level, fmt, args...)			\
+	rte_log(RTE_LOG_ ## level, vfio_user_log_level,		\
+	"VFIO_USER: " fmt, ## args)
+
+struct vfio_user_socket {
+	char *sock_addr;
+	int sock_fd;
+	int dev_id;
+};
+
+typedef enum VFIO_USER_CMD_TYPE {
+	VFIO_USER_NONE = 0,
+	VFIO_USER_VERSION = 1,
+	VFIO_USER_MAX = 2,
+} VFIO_USER_CMD_TYPE;
+
+struct vfio_user_version {
+	uint16_t major;
+	uint16_t minor;
+	/* Version data (JSON), for now not supported */
+	uint8_t ver_data[VFIO_USER_MAX_VERSION_DATA];
+};
+
+typedef struct vfio_user_msg {
+	uint16_t msg_id;
+	uint16_t cmd;
+	uint32_t size;
+#define VFIO_USER_TYPE_CMD	(0x0)		/* Message type is COMMAND */
+#define VFIO_USER_TYPE_REPLY	(0x1 << 0)	/* Message type is REPLY */
+#define VFIO_USER_NEED_NO_RP	(0x1 << 4)	/* Message needs no reply */
+#define VFIO_USER_ERROR		(0x1 << 5)	/* Reply message has error */
+	uint32_t flags;
+	uint32_t err;				/* Valid in reply, optional */
+	union {
+		struct vfio_user_version ver;
+	} payload;
+	int fds[VFIO_USER_MAX_FD];
+	int fd_num;
+} __attribute((packed)) VFIO_USER_MSG;
+
+#define VFIO_USER_MSG_HDR_SIZE offsetof(VFIO_USER_MSG, payload.ver)
+
+void vfio_user_close_msg_fds(VFIO_USER_MSG *msg);
+int vfio_user_check_msg_fdnum(VFIO_USER_MSG *msg, int expected_fds);
+void vfio_user_close_msg_fds(VFIO_USER_MSG *msg);
+int vfio_user_recv_msg(int sockfd, VFIO_USER_MSG *msg);
+int vfio_user_send_msg(int sockfd, VFIO_USER_MSG *msg);
+int vfio_user_reply_msg(int sockfd, VFIO_USER_MSG *msg);
+
+#endif
diff --git a/lib/meson.build b/lib/meson.build
index ed00f89146..b7fbfcc95b 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -28,6 +28,7 @@  libraries = [
 	'rib', 'reorder', 'sched', 'security', 'stack', 'vhost',
 	# ipsec lib depends on net, crypto and security
 	'ipsec',
+	'vfio_user',
 	#fib lib depends on rib
 	'fib',
 	# add pkt framework libs which use other libs from above