diff options
Diffstat (limited to 'drivers/net/tap/tap_netlink.c')
| -rw-r--r-- | drivers/net/tap/tap_netlink.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/drivers/net/tap/tap_netlink.c b/drivers/net/tap/tap_netlink.c new file mode 100644 index 00000000..ee92e2e7 --- /dev/null +++ b/drivers/net/tap/tap_netlink.c @@ -0,0 +1,367 @@ +/*- + * BSD LICENSE + * + * Copyright 2017 6WIND S.A. + * Copyright 2017 Mellanox. + * + * 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 6WIND S.A. 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 <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> + +/* 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 +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) { + RTE_LOG(ERR, PMD, "Unable to create a netlink socket\n"); + return -1; + } + if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &sndbuf_size, sizeof(int))) { + RTE_LOG(ERR, PMD, "Unable to set socket buffer send size\n"); + return -1; + } + if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf_size, sizeof(int))) { + RTE_LOG(ERR, PMD, "Unable to set socket buffer receive size\n"); + return -1; + } + if (bind(fd, (struct sockaddr *)&local, sizeof(local)) < 0) { + RTE_LOG(ERR, PMD, "Unable to bind to the netlink socket\n"); + 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 +nl_final(int nlsk_fd) +{ + if (close(nlsk_fd)) { + RTE_LOG(ERR, PMD, "Failed to close netlink socket: %s (%d)\n", + 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 +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) { + RTE_LOG(ERR, PMD, "Failed to send netlink message: %s (%d)\n", + strerror(errno), errno); + return -1; + } + return send_bytes; +} + +/** + * Check that the kernel sends an appropriate ACK in response to an nl_send(). + * + * @param[in] nlsk_fd + * The netlink socket file descriptor used for communication. + * + * @return + * 0 on success, -1 otherwise with errno set. + */ +int +nl_recv_ack(int nlsk_fd) +{ + return nl_recv(nlsk_fd, NULL, NULL); +} + +/** + * Receive a message from the kernel on the netlink socket, following an + * 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 +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 +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 +nlattr_add8(struct nlmsghdr *nh, unsigned short type, uint8_t data) +{ + 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 +nlattr_add16(struct nlmsghdr *nh, unsigned short type, uint16_t data) +{ + 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 +nlattr_add32(struct nlmsghdr *nh, unsigned short type, uint32_t data) +{ + nlattr_add(nh, type, sizeof(uint32_t), &data); +} + +/** + * Start a nested netlink attribute. + * It must be followed later by a call to 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 +nlattr_nested_start(struct nlmsg *msg, uint16_t type) +{ + struct nested_tail *tail; + + tail = rte_zmalloc(NULL, sizeof(struct nested_tail), 0); + if (!tail) { + RTE_LOG(ERR, PMD, + "Couldn't allocate memory for nested netlink" + " attribute\n"); + return -1; + } + + tail->tail = (struct rtattr *)NLMSG_TAIL(&msg->nh); + + 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 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 +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); +} |