1 files changed, 340 insertions, 0 deletions
diff --git a/src/spdk/dpdk/drivers/net/tap/tap_netlink.c b/src/spdk/dpdk/drivers/net/tap/tap_netlink.c
new file mode 100644
index 00000000..6cb51009
--- /dev/null
+++ b/src/spdk/dpdk/drivers/net/tap/tap_netlink.c
@@ -0,0 +1,340 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright 2017 6WIND S.A.
+ * Copyright 2017 Mellanox Technologies, Ltd
+ */
+
+#include <errno.h>
+#include <inttypes.h>
+#include <linux/netlink.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include <rte_malloc.h>
+#include <tap_netlink.h>
+#include <rte_random.h>
+#include "tap_log.h"
+
+/* Must be quite large to support dumping a huge list of QDISC or filters. */
+#define BUF_SIZE (32 * 1024) /* Size of the buffer to receive kernel messages */
+#define SNDBUF_SIZE 32768 /* Send buffer size for the netlink socket */
+#define RCVBUF_SIZE 32768 /* Receive buffer size for the netlink socket */
+
+struct nested_tail {
+	struct rtattr *tail;
+	struct nested_tail *prev;
+};
+
+/**
+ * Initialize a netlink socket for communicating with the kernel.
+ *
+ * @param nl_groups
+ *   Set it to a netlink group value (e.g. RTMGRP_LINK) to receive messages for
+ *   specific netlink multicast groups. Otherwise, no subscription will be made.
+ *
+ * @return
+ *   netlink socket file descriptor on success, -1 otherwise.
+ */
+int
+tap_nl_init(uint32_t nl_groups)
+{
+	int fd, sndbuf_size = SNDBUF_SIZE, rcvbuf_size = RCVBUF_SIZE;
+	struct sockaddr_nl local = {
+		.nl_family = AF_NETLINK,
+		.nl_groups = nl_groups,
+	};
+
+	fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
+	if (fd < 0) {
+		TAP_LOG(ERR, "Unable to create a netlink socket");
+		return -1;
+	}
+	if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &sndbuf_size, sizeof(int))) {
+		TAP_LOG(ERR, "Unable to set socket buffer send size");
+		return -1;
+	}
+	if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf_size, sizeof(int))) {
+		TAP_LOG(ERR, "Unable to set socket buffer receive size");
+		return -1;
+	}
+	if (bind(fd, (struct sockaddr *)&local, sizeof(local)) < 0) {
+		TAP_LOG(ERR, "Unable to bind to the netlink socket");
+		return -1;
+	}
+	return fd;
+}
+
+/**
+ * Clean up a netlink socket once all communicating with the kernel is finished.
+ *
+ * @param[in] nlsk_fd
+ *   The netlink socket file descriptor used for communication.
+ *
+ * @return
+ *   0 on success, -1 otherwise.
+ */
+int
+tap_nl_final(int nlsk_fd)
+{
+	if (close(nlsk_fd)) {
+		TAP_LOG(ERR, "Failed to close netlink socket: %s (%d)",
+			strerror(errno), errno);
+		return -1;
+	}
+	return 0;
+}
+
+/**
+ * Send a message to the kernel on the netlink socket.
+ *
+ * @param[in] nlsk_fd
+ *   The netlink socket file descriptor used for communication.
+ * @param[in] nh
+ *   The netlink message send to the kernel.
+ *
+ * @return
+ *   the number of sent bytes on success, -1 otherwise.
+ */
+int
+tap_nl_send(int nlsk_fd, struct nlmsghdr *nh)
+{
+	/* man 7 netlink EXAMPLE */
+	struct sockaddr_nl sa = {
+		.nl_family = AF_NETLINK,
+	};
+	struct iovec iov = {
+		.iov_base = nh,
+		.iov_len = nh->nlmsg_len,
+	};
+	struct msghdr msg = {
+		.msg_name = &sa,
+		.msg_namelen = sizeof(sa),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+	};
+	int send_bytes;
+
+	nh->nlmsg_pid = 0; /* communication with the kernel uses pid 0 */
+	nh->nlmsg_seq = (uint32_t)rte_rand();
+	send_bytes = sendmsg(nlsk_fd, &msg, 0);
+	if (send_bytes < 0) {
+		TAP_LOG(ERR, "Failed to send netlink message: %s (%d)",
+			strerror(errno), errno);
+		return -1;
+	}
+	return send_bytes;
+}
+
+/**
+ * Check that the kernel sends an appropriate ACK in response
+ * to an tap_nl_send().
+ *
+ * @param[in] nlsk_fd
+ *   The netlink socket file descriptor used for communication.
+ *
+ * @return
+ *   0 on success, -1 otherwise with errno set.
+ */
+int
+tap_nl_recv_ack(int nlsk_fd)
+{
+	return tap_nl_recv(nlsk_fd, NULL, NULL);
+}
+
+/**
+ * Receive a message from the kernel on the netlink socket, following an
+ * tap_nl_send().
+ *
+ * @param[in] nlsk_fd
+ *   The netlink socket file descriptor used for communication.
+ * @param[in] cb
+ *   The callback function to call for each netlink message received.
+ * @param[in, out] arg
+ *   Custom arguments for the callback.
+ *
+ * @return
+ *   0 on success, -1 otherwise with errno set.
+ */
+int
+tap_nl_recv(int nlsk_fd, int (*cb)(struct nlmsghdr *, void *arg), void *arg)
+{
+	/* man 7 netlink EXAMPLE */
+	struct sockaddr_nl sa;
+	char buf[BUF_SIZE];
+	struct iovec iov = {
+		.iov_base = buf,
+		.iov_len = sizeof(buf),
+	};
+	struct msghdr msg = {
+		.msg_name = &sa,
+		.msg_namelen = sizeof(sa),
+		.msg_iov = &iov,
+		/* One message at a time */
+		.msg_iovlen = 1,
+	};
+	int multipart = 0;
+	int ret = 0;
+
+	do {
+		struct nlmsghdr *nh;
+		int recv_bytes = 0;
+
+		recv_bytes = recvmsg(nlsk_fd, &msg, 0);
+		if (recv_bytes < 0)
+			return -1;
+		for (nh = (struct nlmsghdr *)buf;
+		     NLMSG_OK(nh, (unsigned int)recv_bytes);
+		     nh = NLMSG_NEXT(nh, recv_bytes)) {
+			if (nh->nlmsg_type == NLMSG_ERROR) {
+				struct nlmsgerr *err_data = NLMSG_DATA(nh);
+
+				if (err_data->error < 0) {
+					errno = -err_data->error;
+					return -1;
+				}
+				/* Ack message. */
+				return 0;
+			}
+			/* Multi-part msgs and their trailing DONE message. */
+			if (nh->nlmsg_flags & NLM_F_MULTI) {
+				if (nh->nlmsg_type == NLMSG_DONE)
+					return 0;
+				multipart = 1;
+			}
+			if (cb)
+				ret = cb(nh, arg);
+		}
+	} while (multipart);
+	return ret;
+}
+
+/**
+ * Append a netlink attribute to a message.
+ *
+ * @param[in, out] nh
+ *   The netlink message to parse, received from the kernel.
+ * @param[in] type
+ *   The type of attribute to append.
+ * @param[in] data_len
+ *   The length of the data to append.
+ * @param[in] data
+ *   The data to append.
+ */
+void
+tap_nlattr_add(struct nlmsghdr *nh, unsigned short type,
+	   unsigned int data_len, const void *data)
+{
+	/* see man 3 rtnetlink */
+	struct rtattr *rta;
+
+	rta = (struct rtattr *)NLMSG_TAIL(nh);
+	rta->rta_len = RTA_LENGTH(data_len);
+	rta->rta_type = type;
+	memcpy(RTA_DATA(rta), data, data_len);
+	nh->nlmsg_len = NLMSG_ALIGN(nh->nlmsg_len) + RTA_ALIGN(rta->rta_len);
+}
+
+/**
+ * Append a uint8_t netlink attribute to a message.
+ *
+ * @param[in, out] nh
+ *   The netlink message to parse, received from the kernel.
+ * @param[in] type
+ *   The type of attribute to append.
+ * @param[in] data
+ *   The data to append.
+ */
+void
+tap_nlattr_add8(struct nlmsghdr *nh, unsigned short type, uint8_t data)
+{
+	tap_nlattr_add(nh, type, sizeof(uint8_t), &data);
+}
+
+/**
+ * Append a uint16_t netlink attribute to a message.
+ *
+ * @param[in, out] nh
+ *   The netlink message to parse, received from the kernel.
+ * @param[in] type
+ *   The type of attribute to append.
+ * @param[in] data
+ *   The data to append.
+ */
+void
+tap_nlattr_add16(struct nlmsghdr *nh, unsigned short type, uint16_t data)
+{
+	tap_nlattr_add(nh, type, sizeof(uint16_t), &data);
+}
+
+/**
+ * Append a uint16_t netlink attribute to a message.
+ *
+ * @param[in, out] nh
+ *   The netlink message to parse, received from the kernel.
+ * @param[in] type
+ *   The type of attribute to append.
+ * @param[in] data
+ *   The data to append.
+ */
+void
+tap_nlattr_add32(struct nlmsghdr *nh, unsigned short type, uint32_t data)
+{
+	tap_nlattr_add(nh, type, sizeof(uint32_t), &data);
+}
+
+/**
+ * Start a nested netlink attribute.
+ * It must be followed later by a call to tap_nlattr_nested_finish().
+ *
+ * @param[in, out] msg
+ *   The netlink message where to edit the nested_tails metadata.
+ * @param[in] type
+ *   The nested attribute type to append.
+ *
+ * @return
+ *   -1 if adding a nested netlink attribute failed, 0 otherwise.
+ */
+int
+tap_nlattr_nested_start(struct nlmsg *msg, uint16_t type)
+{
+	struct nested_tail *tail;
+
+	tail = rte_zmalloc(NULL, sizeof(struct nested_tail), 0);
+	if (!tail) {
+		TAP_LOG(ERR,
+			"Couldn't allocate memory for nested netlink attribute");
+		return -1;
+	}
+
+	tail->tail = (struct rtattr *)NLMSG_TAIL(&msg->nh);
+
+	tap_nlattr_add(&msg->nh, type, 0, NULL);
+
+	tail->prev = msg->nested_tails;
+
+	msg->nested_tails = tail;
+
+	return 0;
+}
+
+/**
+ * End a nested netlink attribute.
+ * It follows a call to tap_nlattr_nested_start().
+ * In effect, it will modify the nested attribute length to include every bytes
+ * from the nested attribute start, up to here.
+ *
+ * @param[in, out] msg
+ *   The netlink message where to edit the nested_tails metadata.
+ */
+void
+tap_nlattr_nested_finish(struct nlmsg *msg)
+{
+	struct nested_tail *tail = msg->nested_tails;
+
+	tail->tail->rta_len = (char *)NLMSG_TAIL(&msg->nh) - (char *)tail->tail;
+
+	if (tail->prev)
+		msg->nested_tails = tail->prev;
+
+	rte_free(tail);
+}