New upstream version 18.08
[deb_dpdk.git] / drivers / net / mlx5 / mlx5_nl.c
diff --git a/drivers/net/mlx5/mlx5_nl.c b/drivers/net/mlx5/mlx5_nl.c
new file mode 100644 (file)
index 0000000..d61826a
--- /dev/null
@@ -0,0 +1,916 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright 2018 6WIND S.A.
+ * Copyright 2018 Mellanox Technologies, Ltd
+ */
+
+#include <errno.h>
+#include <linux/if_link.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <net/if.h>
+#include <rdma/rdma_netlink.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include <rte_errno.h>
+
+#include "mlx5.h"
+#include "mlx5_utils.h"
+
+/* Size of the buffer to receive kernel messages */
+#define MLX5_NL_BUF_SIZE (32 * 1024)
+/* Send buffer size for the Netlink socket */
+#define MLX5_SEND_BUF_SIZE 32768
+/* Receive buffer size for the Netlink socket */
+#define MLX5_RECV_BUF_SIZE 32768
+
+/*
+ * Define NDA_RTA as defined in iproute2 sources.
+ *
+ * see in iproute2 sources file include/libnetlink.h
+ */
+#ifndef MLX5_NDA_RTA
+#define MLX5_NDA_RTA(r) \
+       ((struct rtattr *)(((char *)(r)) + NLMSG_ALIGN(sizeof(struct ndmsg))))
+#endif
+
+/*
+ * The following definitions are normally found in rdma/rdma_netlink.h,
+ * however they are so recent that most systems do not expose them yet.
+ */
+#ifndef HAVE_RDMA_NL_NLDEV
+#define RDMA_NL_NLDEV 5
+#endif
+#ifndef HAVE_RDMA_NLDEV_CMD_GET
+#define RDMA_NLDEV_CMD_GET 1
+#endif
+#ifndef HAVE_RDMA_NLDEV_CMD_PORT_GET
+#define RDMA_NLDEV_CMD_PORT_GET 5
+#endif
+#ifndef HAVE_RDMA_NLDEV_ATTR_DEV_INDEX
+#define RDMA_NLDEV_ATTR_DEV_INDEX 1
+#endif
+#ifndef HAVE_RDMA_NLDEV_ATTR_DEV_NAME
+#define RDMA_NLDEV_ATTR_DEV_NAME 2
+#endif
+#ifndef HAVE_RDMA_NLDEV_ATTR_PORT_INDEX
+#define RDMA_NLDEV_ATTR_PORT_INDEX 3
+#endif
+#ifndef HAVE_RDMA_NLDEV_ATTR_NDEV_INDEX
+#define RDMA_NLDEV_ATTR_NDEV_INDEX 50
+#endif
+
+/* These are normally found in linux/if_link.h. */
+#ifndef HAVE_IFLA_PHYS_SWITCH_ID
+#define IFLA_PHYS_SWITCH_ID 36
+#endif
+#ifndef HAVE_IFLA_PHYS_PORT_NAME
+#define IFLA_PHYS_PORT_NAME 38
+#endif
+
+/* Add/remove MAC address through Netlink */
+struct mlx5_nl_mac_addr {
+       struct ether_addr (*mac)[];
+       /**< MAC address handled by the device. */
+       int mac_n; /**< Number of addresses in the array. */
+};
+
+/** Data structure used by mlx5_nl_ifindex_cb(). */
+struct mlx5_nl_ifindex_data {
+       const char *name; /**< IB device name (in). */
+       uint32_t ibindex; /**< IB device index (out). */
+       uint32_t ifindex; /**< Network interface index (out). */
+};
+
+/**
+ * Opens a Netlink socket.
+ *
+ * @param protocol
+ *   Netlink protocol (e.g. NETLINK_ROUTE, NETLINK_RDMA).
+ *
+ * @return
+ *   A file descriptor on success, a negative errno value otherwise and
+ *   rte_errno is set.
+ */
+int
+mlx5_nl_init(int protocol)
+{
+       int fd;
+       int sndbuf_size = MLX5_SEND_BUF_SIZE;
+       int rcvbuf_size = MLX5_RECV_BUF_SIZE;
+       struct sockaddr_nl local = {
+               .nl_family = AF_NETLINK,
+       };
+       int ret;
+
+       fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
+       if (fd == -1) {
+               rte_errno = errno;
+               return -rte_errno;
+       }
+       ret = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &sndbuf_size, sizeof(int));
+       if (ret == -1) {
+               rte_errno = errno;
+               goto error;
+       }
+       ret = setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf_size, sizeof(int));
+       if (ret == -1) {
+               rte_errno = errno;
+               goto error;
+       }
+       ret = bind(fd, (struct sockaddr *)&local, sizeof(local));
+       if (ret == -1) {
+               rte_errno = errno;
+               goto error;
+       }
+       return fd;
+error:
+       close(fd);
+       return -rte_errno;
+}
+
+/**
+ * Send a request message to the kernel on the Netlink socket.
+ *
+ * @param[in] nlsk_fd
+ *   Netlink socket file descriptor.
+ * @param[in] nh
+ *   The Netlink message send to the kernel.
+ * @param[in] ssn
+ *   Sequence number.
+ * @param[in] req
+ *   Pointer to the request structure.
+ * @param[in] len
+ *   Length of the request in bytes.
+ *
+ * @return
+ *   The number of sent bytes on success, a negative errno value otherwise and
+ *   rte_errno is set.
+ */
+static int
+mlx5_nl_request(int nlsk_fd, struct nlmsghdr *nh, uint32_t sn, void *req,
+               int len)
+{
+       struct sockaddr_nl sa = {
+               .nl_family = AF_NETLINK,
+       };
+       struct iovec iov[2] = {
+               { .iov_base = nh, .iov_len = sizeof(*nh), },
+               { .iov_base = req, .iov_len = len, },
+       };
+       struct msghdr msg = {
+               .msg_name = &sa,
+               .msg_namelen = sizeof(sa),
+               .msg_iov = iov,
+               .msg_iovlen = 2,
+       };
+       int send_bytes;
+
+       nh->nlmsg_pid = 0; /* communication with the kernel uses pid 0 */
+       nh->nlmsg_seq = sn;
+       send_bytes = sendmsg(nlsk_fd, &msg, 0);
+       if (send_bytes < 0) {
+               rte_errno = errno;
+               return -rte_errno;
+       }
+       return send_bytes;
+}
+
+/**
+ * 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.
+ * @param[in] sn
+ *   Sequence number.
+ *
+ * @return
+ *   The number of sent bytes on success, a negative errno value otherwise and
+ *   rte_errno is set.
+ */
+static int
+mlx5_nl_send(int nlsk_fd, struct nlmsghdr *nh, uint32_t sn)
+{
+       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 = sn;
+       send_bytes = sendmsg(nlsk_fd, &msg, 0);
+       if (send_bytes < 0) {
+               rte_errno = errno;
+               return -rte_errno;
+       }
+       return send_bytes;
+}
+
+/**
+ * Receive a message from the kernel on the Netlink socket, following
+ * mlx5_nl_send().
+ *
+ * @param[in] nlsk_fd
+ *   The Netlink socket file descriptor used for communication.
+ * @param[in] sn
+ *   Sequence number.
+ * @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, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+mlx5_nl_recv(int nlsk_fd, uint32_t sn, int (*cb)(struct nlmsghdr *, void *arg),
+            void *arg)
+{
+       struct sockaddr_nl sa;
+       char buf[MLX5_RECV_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;
+
+               do {
+                       recv_bytes = recvmsg(nlsk_fd, &msg, 0);
+                       if (recv_bytes == -1) {
+                               rte_errno = errno;
+                               return -rte_errno;
+                       }
+                       nh = (struct nlmsghdr *)buf;
+               } while (nh->nlmsg_seq != sn);
+               for (;
+                    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) {
+                                       rte_errno = -err_data->error;
+                                       return -rte_errno;
+                               }
+                               /* 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);
+                               if (ret < 0)
+                                       return ret;
+                       }
+               }
+       } while (multipart);
+       return ret;
+}
+
+/**
+ * Parse Netlink message to retrieve the bridge MAC address.
+ *
+ * @param nh
+ *   Pointer to Netlink Message Header.
+ * @param arg
+ *   PMD data register with this callback.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+mlx5_nl_mac_addr_cb(struct nlmsghdr *nh, void *arg)
+{
+       struct mlx5_nl_mac_addr *data = arg;
+       struct ndmsg *r = NLMSG_DATA(nh);
+       struct rtattr *attribute;
+       int len;
+
+       len = nh->nlmsg_len - NLMSG_LENGTH(sizeof(*r));
+       for (attribute = MLX5_NDA_RTA(r);
+            RTA_OK(attribute, len);
+            attribute = RTA_NEXT(attribute, len)) {
+               if (attribute->rta_type == NDA_LLADDR) {
+                       if (data->mac_n == MLX5_MAX_MAC_ADDRESSES) {
+                               DRV_LOG(WARNING,
+                                       "not enough room to finalize the"
+                                       " request");
+                               rte_errno = ENOMEM;
+                               return -rte_errno;
+                       }
+#ifndef NDEBUG
+                       char m[18];
+
+                       ether_format_addr(m, 18, RTA_DATA(attribute));
+                       DRV_LOG(DEBUG, "bridge MAC address %s", m);
+#endif
+                       memcpy(&(*data->mac)[data->mac_n++],
+                              RTA_DATA(attribute), ETHER_ADDR_LEN);
+               }
+       }
+       return 0;
+}
+
+/**
+ * Get bridge MAC addresses.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param mac[out]
+ *   Pointer to the array table of MAC addresses to fill.
+ *   Its size should be of MLX5_MAX_MAC_ADDRESSES.
+ * @param mac_n[out]
+ *   Number of entries filled in MAC array.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+mlx5_nl_mac_addr_list(struct rte_eth_dev *dev, struct ether_addr (*mac)[],
+                     int *mac_n)
+{
+       struct priv *priv = dev->data->dev_private;
+       unsigned int iface_idx = mlx5_ifindex(dev);
+       struct {
+               struct nlmsghdr hdr;
+               struct ifinfomsg ifm;
+       } req = {
+               .hdr = {
+                       .nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+                       .nlmsg_type = RTM_GETNEIGH,
+                       .nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+               },
+               .ifm = {
+                       .ifi_family = PF_BRIDGE,
+                       .ifi_index = iface_idx,
+               },
+       };
+       struct mlx5_nl_mac_addr data = {
+               .mac = mac,
+               .mac_n = 0,
+       };
+       int fd;
+       int ret;
+       uint32_t sn = priv->nl_sn++;
+
+       if (priv->nl_socket_route == -1)
+               return 0;
+       fd = priv->nl_socket_route;
+       ret = mlx5_nl_request(fd, &req.hdr, sn, &req.ifm,
+                             sizeof(struct ifinfomsg));
+       if (ret < 0)
+               goto error;
+       ret = mlx5_nl_recv(fd, sn, mlx5_nl_mac_addr_cb, &data);
+       if (ret < 0)
+               goto error;
+       *mac_n = data.mac_n;
+       return 0;
+error:
+       DRV_LOG(DEBUG, "port %u cannot retrieve MAC address list %s",
+               dev->data->port_id, strerror(rte_errno));
+       return -rte_errno;
+}
+
+/**
+ * Modify the MAC address neighbour table with Netlink.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param mac
+ *   MAC address to consider.
+ * @param add
+ *   1 to add the MAC address, 0 to remove the MAC address.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+mlx5_nl_mac_addr_modify(struct rte_eth_dev *dev, struct ether_addr *mac,
+                       int add)
+{
+       struct priv *priv = dev->data->dev_private;
+       unsigned int iface_idx = mlx5_ifindex(dev);
+       struct {
+               struct nlmsghdr hdr;
+               struct ndmsg ndm;
+               struct rtattr rta;
+               uint8_t buffer[ETHER_ADDR_LEN];
+       } req = {
+               .hdr = {
+                       .nlmsg_len = NLMSG_LENGTH(sizeof(struct ndmsg)),
+                       .nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE |
+                               NLM_F_EXCL | NLM_F_ACK,
+                       .nlmsg_type = add ? RTM_NEWNEIGH : RTM_DELNEIGH,
+               },
+               .ndm = {
+                       .ndm_family = PF_BRIDGE,
+                       .ndm_state = NUD_NOARP | NUD_PERMANENT,
+                       .ndm_ifindex = iface_idx,
+                       .ndm_flags = NTF_SELF,
+               },
+               .rta = {
+                       .rta_type = NDA_LLADDR,
+                       .rta_len = RTA_LENGTH(ETHER_ADDR_LEN),
+               },
+       };
+       int fd;
+       int ret;
+       uint32_t sn = priv->nl_sn++;
+
+       if (priv->nl_socket_route == -1)
+               return 0;
+       fd = priv->nl_socket_route;
+       memcpy(RTA_DATA(&req.rta), mac, ETHER_ADDR_LEN);
+       req.hdr.nlmsg_len = NLMSG_ALIGN(req.hdr.nlmsg_len) +
+               RTA_ALIGN(req.rta.rta_len);
+       ret = mlx5_nl_send(fd, &req.hdr, sn);
+       if (ret < 0)
+               goto error;
+       ret = mlx5_nl_recv(fd, sn, NULL, NULL);
+       if (ret < 0)
+               goto error;
+       return 0;
+error:
+       DRV_LOG(DEBUG,
+               "port %u cannot %s MAC address %02X:%02X:%02X:%02X:%02X:%02X"
+               " %s",
+               dev->data->port_id,
+               add ? "add" : "remove",
+               mac->addr_bytes[0], mac->addr_bytes[1],
+               mac->addr_bytes[2], mac->addr_bytes[3],
+               mac->addr_bytes[4], mac->addr_bytes[5],
+               strerror(rte_errno));
+       return -rte_errno;
+}
+
+/**
+ * Add a MAC address.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param mac
+ *   MAC address to register.
+ * @param index
+ *   MAC address index.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+int
+mlx5_nl_mac_addr_add(struct rte_eth_dev *dev, struct ether_addr *mac,
+                    uint32_t index)
+{
+       struct priv *priv = dev->data->dev_private;
+       int ret;
+
+       ret = mlx5_nl_mac_addr_modify(dev, mac, 1);
+       if (!ret)
+               BITFIELD_SET(priv->mac_own, index);
+       if (ret == -EEXIST)
+               return 0;
+       return ret;
+}
+
+/**
+ * Remove a MAC address.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param mac
+ *   MAC address to remove.
+ * @param index
+ *   MAC address index.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+int
+mlx5_nl_mac_addr_remove(struct rte_eth_dev *dev, struct ether_addr *mac,
+                       uint32_t index)
+{
+       struct priv *priv = dev->data->dev_private;
+
+       BITFIELD_RESET(priv->mac_own, index);
+       return mlx5_nl_mac_addr_modify(dev, mac, 0);
+}
+
+/**
+ * Synchronize Netlink bridge table to the internal table.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ */
+void
+mlx5_nl_mac_addr_sync(struct rte_eth_dev *dev)
+{
+       struct ether_addr macs[MLX5_MAX_MAC_ADDRESSES];
+       int macs_n = 0;
+       int i;
+       int ret;
+
+       ret = mlx5_nl_mac_addr_list(dev, &macs, &macs_n);
+       if (ret)
+               return;
+       for (i = 0; i != macs_n; ++i) {
+               int j;
+
+               /* Verify the address is not in the array yet. */
+               for (j = 0; j != MLX5_MAX_MAC_ADDRESSES; ++j)
+                       if (is_same_ether_addr(&macs[i],
+                                              &dev->data->mac_addrs[j]))
+                               break;
+               if (j != MLX5_MAX_MAC_ADDRESSES)
+                       continue;
+               /* Find the first entry available. */
+               for (j = 0; j != MLX5_MAX_MAC_ADDRESSES; ++j) {
+                       if (is_zero_ether_addr(&dev->data->mac_addrs[j])) {
+                               dev->data->mac_addrs[j] = macs[i];
+                               break;
+                       }
+               }
+       }
+}
+
+/**
+ * Flush all added MAC addresses.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ */
+void
+mlx5_nl_mac_addr_flush(struct rte_eth_dev *dev)
+{
+       struct priv *priv = dev->data->dev_private;
+       int i;
+
+       for (i = MLX5_MAX_MAC_ADDRESSES - 1; i >= 0; --i) {
+               struct ether_addr *m = &dev->data->mac_addrs[i];
+
+               if (BITFIELD_ISSET(priv->mac_own, i))
+                       mlx5_nl_mac_addr_remove(dev, m, i);
+       }
+}
+
+/**
+ * Enable promiscuous / all multicast mode through Netlink.
+ *
+ * @param dev
+ *   Pointer to Ethernet device structure.
+ * @param flags
+ *   IFF_PROMISC for promiscuous, IFF_ALLMULTI for allmulti.
+ * @param enable
+ *   Nonzero to enable, disable otherwise.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+mlx5_nl_device_flags(struct rte_eth_dev *dev, uint32_t flags, int enable)
+{
+       struct priv *priv = dev->data->dev_private;
+       unsigned int iface_idx = mlx5_ifindex(dev);
+       struct {
+               struct nlmsghdr hdr;
+               struct ifinfomsg ifi;
+       } req = {
+               .hdr = {
+                       .nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+                       .nlmsg_type = RTM_NEWLINK,
+                       .nlmsg_flags = NLM_F_REQUEST,
+               },
+               .ifi = {
+                       .ifi_flags = enable ? flags : 0,
+                       .ifi_change = flags,
+                       .ifi_index = iface_idx,
+               },
+       };
+       int fd;
+       int ret;
+
+       assert(!(flags & ~(IFF_PROMISC | IFF_ALLMULTI)));
+       if (priv->nl_socket_route < 0)
+               return 0;
+       fd = priv->nl_socket_route;
+       ret = mlx5_nl_send(fd, &req.hdr, priv->nl_sn++);
+       if (ret < 0)
+               return ret;
+       return 0;
+}
+
+/**
+ * Enable promiscuous mode through Netlink.
+ *
+ * @param dev
+ *   Pointer to Ethernet device structure.
+ * @param enable
+ *   Nonzero to enable, disable otherwise.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+int
+mlx5_nl_promisc(struct rte_eth_dev *dev, int enable)
+{
+       int ret = mlx5_nl_device_flags(dev, IFF_PROMISC, enable);
+
+       if (ret)
+               DRV_LOG(DEBUG,
+                       "port %u cannot %s promisc mode: Netlink error %s",
+                       dev->data->port_id, enable ? "enable" : "disable",
+                       strerror(rte_errno));
+       return ret;
+}
+
+/**
+ * Enable all multicast mode through Netlink.
+ *
+ * @param dev
+ *   Pointer to Ethernet device structure.
+ * @param enable
+ *   Nonzero to enable, disable otherwise.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+int
+mlx5_nl_allmulti(struct rte_eth_dev *dev, int enable)
+{
+       int ret = mlx5_nl_device_flags(dev, IFF_ALLMULTI, enable);
+
+       if (ret)
+               DRV_LOG(DEBUG,
+                       "port %u cannot %s allmulti mode: Netlink error %s",
+                       dev->data->port_id, enable ? "enable" : "disable",
+                       strerror(rte_errno));
+       return ret;
+}
+
+/**
+ * Process network interface information from Netlink message.
+ *
+ * @param nh
+ *   Pointer to Netlink message header.
+ * @param arg
+ *   Opaque data pointer for this callback.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+mlx5_nl_ifindex_cb(struct nlmsghdr *nh, void *arg)
+{
+       struct mlx5_nl_ifindex_data *data = arg;
+       size_t off = NLMSG_HDRLEN;
+       uint32_t ibindex = 0;
+       uint32_t ifindex = 0;
+       int found = 0;
+
+       if (nh->nlmsg_type !=
+           RDMA_NL_GET_TYPE(RDMA_NL_NLDEV, RDMA_NLDEV_CMD_GET) &&
+           nh->nlmsg_type !=
+           RDMA_NL_GET_TYPE(RDMA_NL_NLDEV, RDMA_NLDEV_CMD_PORT_GET))
+               goto error;
+       while (off < nh->nlmsg_len) {
+               struct nlattr *na = (void *)((uintptr_t)nh + off);
+               void *payload = (void *)((uintptr_t)na + NLA_HDRLEN);
+
+               if (na->nla_len > nh->nlmsg_len - off)
+                       goto error;
+               switch (na->nla_type) {
+               case RDMA_NLDEV_ATTR_DEV_INDEX:
+                       ibindex = *(uint32_t *)payload;
+                       break;
+               case RDMA_NLDEV_ATTR_DEV_NAME:
+                       if (!strcmp(payload, data->name))
+                               found = 1;
+                       break;
+               case RDMA_NLDEV_ATTR_NDEV_INDEX:
+                       ifindex = *(uint32_t *)payload;
+                       break;
+               default:
+                       break;
+               }
+               off += NLA_ALIGN(na->nla_len);
+       }
+       if (found) {
+               data->ibindex = ibindex;
+               data->ifindex = ifindex;
+       }
+       return 0;
+error:
+       rte_errno = EINVAL;
+       return -rte_errno;
+}
+
+/**
+ * Get index of network interface associated with some IB device.
+ *
+ * This is the only somewhat safe method to avoid resorting to heuristics
+ * when faced with port representors. Unfortunately it requires at least
+ * Linux 4.17.
+ *
+ * @param nl
+ *   Netlink socket of the RDMA kind (NETLINK_RDMA).
+ * @param[in] name
+ *   IB device name.
+ *
+ * @return
+ *   A valid (nonzero) interface index on success, 0 otherwise and rte_errno
+ *   is set.
+ */
+unsigned int
+mlx5_nl_ifindex(int nl, const char *name)
+{
+       static const uint32_t pindex = 1;
+       uint32_t seq = random();
+       struct mlx5_nl_ifindex_data data = {
+               .name = name,
+               .ibindex = 0, /* Determined during first pass. */
+               .ifindex = 0, /* Determined during second pass. */
+       };
+       union {
+               struct nlmsghdr nh;
+               uint8_t buf[NLMSG_HDRLEN +
+                           NLA_HDRLEN + NLA_ALIGN(sizeof(data.ibindex)) +
+                           NLA_HDRLEN + NLA_ALIGN(sizeof(pindex))];
+       } req = {
+               .nh = {
+                       .nlmsg_len = NLMSG_LENGTH(0),
+                       .nlmsg_type = RDMA_NL_GET_TYPE(RDMA_NL_NLDEV,
+                                                      RDMA_NLDEV_CMD_GET),
+                       .nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP,
+               },
+       };
+       struct nlattr *na;
+       int ret;
+
+       ret = mlx5_nl_send(nl, &req.nh, seq);
+       if (ret < 0)
+               return 0;
+       ret = mlx5_nl_recv(nl, seq, mlx5_nl_ifindex_cb, &data);
+       if (ret < 0)
+               return 0;
+       if (!data.ibindex)
+               goto error;
+       ++seq;
+       req.nh.nlmsg_type = RDMA_NL_GET_TYPE(RDMA_NL_NLDEV,
+                                            RDMA_NLDEV_CMD_PORT_GET);
+       req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+       req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.buf) - NLMSG_HDRLEN);
+       na = (void *)((uintptr_t)req.buf + NLMSG_HDRLEN);
+       na->nla_len = NLA_HDRLEN + sizeof(data.ibindex);
+       na->nla_type = RDMA_NLDEV_ATTR_DEV_INDEX;
+       memcpy((void *)((uintptr_t)na + NLA_HDRLEN),
+              &data.ibindex, sizeof(data.ibindex));
+       na = (void *)((uintptr_t)na + NLA_ALIGN(na->nla_len));
+       na->nla_len = NLA_HDRLEN + sizeof(pindex);
+       na->nla_type = RDMA_NLDEV_ATTR_PORT_INDEX;
+       memcpy((void *)((uintptr_t)na + NLA_HDRLEN),
+              &pindex, sizeof(pindex));
+       ret = mlx5_nl_send(nl, &req.nh, seq);
+       if (ret < 0)
+               return 0;
+       ret = mlx5_nl_recv(nl, seq, mlx5_nl_ifindex_cb, &data);
+       if (ret < 0)
+               return 0;
+       if (!data.ifindex)
+               goto error;
+       return data.ifindex;
+error:
+       rte_errno = ENODEV;
+       return 0;
+}
+
+/**
+ * Process switch information from Netlink message.
+ *
+ * @param nh
+ *   Pointer to Netlink message header.
+ * @param arg
+ *   Opaque data pointer for this callback.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+static int
+mlx5_nl_switch_info_cb(struct nlmsghdr *nh, void *arg)
+{
+       struct mlx5_switch_info info = {
+               .master = 0,
+               .representor = 0,
+               .port_name = 0,
+               .switch_id = 0,
+       };
+       size_t off = NLMSG_LENGTH(sizeof(struct ifinfomsg));
+       bool port_name_set = false;
+       bool switch_id_set = false;
+
+       if (nh->nlmsg_type != RTM_NEWLINK)
+               goto error;
+       while (off < nh->nlmsg_len) {
+               struct rtattr *ra = (void *)((uintptr_t)nh + off);
+               void *payload = RTA_DATA(ra);
+               char *end;
+               unsigned int i;
+
+               if (ra->rta_len > nh->nlmsg_len - off)
+                       goto error;
+               switch (ra->rta_type) {
+               case IFLA_PHYS_PORT_NAME:
+                       errno = 0;
+                       info.port_name = strtol(payload, &end, 0);
+                       if (errno ||
+                           (size_t)(end - (char *)payload) != strlen(payload))
+                               goto error;
+                       port_name_set = true;
+                       break;
+               case IFLA_PHYS_SWITCH_ID:
+                       info.switch_id = 0;
+                       for (i = 0; i < RTA_PAYLOAD(ra); ++i) {
+                               info.switch_id <<= 8;
+                               info.switch_id |= ((uint8_t *)payload)[i];
+                       }
+                       switch_id_set = true;
+                       break;
+               }
+               off += RTA_ALIGN(ra->rta_len);
+       }
+       info.master = switch_id_set && !port_name_set;
+       info.representor = switch_id_set && port_name_set;
+       memcpy(arg, &info, sizeof(info));
+       return 0;
+error:
+       rte_errno = EINVAL;
+       return -rte_errno;
+}
+
+/**
+ * Get switch information associated with network interface.
+ *
+ * @param nl
+ *   Netlink socket of the ROUTE kind (NETLINK_ROUTE).
+ * @param ifindex
+ *   Network interface index.
+ * @param[out] info
+ *   Switch information object, populated in case of success.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+int
+mlx5_nl_switch_info(int nl, unsigned int ifindex, struct mlx5_switch_info *info)
+{
+       uint32_t seq = random();
+       struct {
+               struct nlmsghdr nh;
+               struct ifinfomsg info;
+       } req = {
+               .nh = {
+                       .nlmsg_len = NLMSG_LENGTH(sizeof(req.info)),
+                       .nlmsg_type = RTM_GETLINK,
+                       .nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK,
+               },
+               .info = {
+                       .ifi_family = AF_UNSPEC,
+                       .ifi_index = ifindex,
+               },
+       };
+       int ret;
+
+       ret = mlx5_nl_send(nl, &req.nh, seq);
+       if (ret >= 0)
+               ret = mlx5_nl_recv(nl, seq, mlx5_nl_switch_info_cb, info);
+       return ret;
+}