Add TAP device creation using the Linux TUN/TAP interface with IFF_MULTI_QUEUE, IFF_NO_PI, and IFF_VNET_HDR flags. Enable NAPI mode when the kernel supports it.
The driver maintains a keep-alive file descriptor to the TAP device and opens additional per-queue file descriptors for data path I/O. This mirrors the multi-queue TAP architecture where each queue pair (rx + tx) shares a single TAP fd. Add the rtap_create() function that: - Opens the TAP device with configurable interface name - Configures the virtio-net header size - Reads the kernel-assigned MAC address - Supports the 'persist' option to keep the interface after exit - Detaches the keep-alive queue from data traffic Add rtap_queue_open() and rtap_queue_close() for per-queue fd management used during queue setup and teardown. Signed-off-by: Stephen Hemminger <[email protected]> --- drivers/net/rtap/rtap.h | 4 + drivers/net/rtap/rtap_ethdev.c | 216 ++++++++++++++++++++++++++++++++- 2 files changed, 219 insertions(+), 1 deletion(-) diff --git a/drivers/net/rtap/rtap.h b/drivers/net/rtap/rtap.h index 507ab000f3..39a3188a7b 100644 --- a/drivers/net/rtap/rtap.h +++ b/drivers/net/rtap/rtap.h @@ -66,4 +66,8 @@ struct rtap_pmd { struct rte_ether_addr eth_addr; /* address assigned by kernel */ }; +/* rtap_ethdev.c */ +int rtap_queue_open(struct rte_eth_dev *dev, uint16_t queue_id); +void rtap_queue_close(struct rte_eth_dev *dev, uint16_t queue_id); + #endif /* _RTAP_H_ */ diff --git a/drivers/net/rtap/rtap_ethdev.c b/drivers/net/rtap/rtap_ethdev.c index ee5b5bad1b..4e7847ff8d 100644 --- a/drivers/net/rtap/rtap_ethdev.c +++ b/drivers/net/rtap/rtap_ethdev.c @@ -39,13 +39,140 @@ static const char * const valid_arguments[] = { NULL }; +/* Creates a new tap device, name returned in ifr */ +static int +rtap_tap_open(const char *name, struct ifreq *ifr, uint8_t persist) +{ + static const char tun_dev[] = "/dev/net/tun"; + int tap_fd; + + tap_fd = open(tun_dev, O_RDWR | O_CLOEXEC | O_NONBLOCK); + if (tap_fd < 0) { + PMD_LOG_ERRNO(ERR, "Open %s failed", tun_dev); + return -1; + } + + int features = 0; + if (ioctl(tap_fd, TUNGETFEATURES, &features) < 0) { + PMD_LOG_ERRNO(ERR, "ioctl(TUNGETFEATURES): %s", tun_dev); + goto error; + } + + int flags = IFF_TAP | IFF_MULTI_QUEUE | IFF_NO_PI | IFF_VNET_HDR; + if ((features & flags) != flags) { + PMD_LOG(ERR, "TUN features %#x missing support for %#x", + features, features & flags); + goto error; + } + +#ifdef IFF_NAPI + /* If kernel supports using NAPI enable it */ + if (features & IFF_NAPI) + flags |= IFF_NAPI; +#endif + /* + * Sets the device name and packet format. + * Do not want the protocol information (PI) + */ + strlcpy(ifr->ifr_name, name, IFNAMSIZ); + ifr->ifr_flags = flags; + if (ioctl(tap_fd, TUNSETIFF, ifr) < 0) { + PMD_LOG_ERRNO(ERR, "ioctl(TUNSETIFF) %s", ifr->ifr_name); + goto error; + } + + /* (Optional) keep the device after application exit */ + if (persist && ioctl(tap_fd, TUNSETPERSIST, 1) < 0) { + PMD_LOG_ERRNO(ERR, "ioctl(TUNSETPERSIST) %s", ifr->ifr_name); + goto error; + } + + int hdr_size = sizeof(struct virtio_net_hdr); + if (ioctl(tap_fd, TUNSETVNETHDRSZ, &hdr_size) < 0) { + PMD_LOG(ERR, "ioctl(TUNSETVNETHDRSZ) %s", strerror(errno)); + goto error; + } + + return tap_fd; +error: + close(tap_fd); + return -1; +} + +static int +rtap_dev_start(struct rte_eth_dev *dev) +{ + dev->data->dev_link.link_status = RTE_ETH_LINK_UP; + for (uint16_t i = 0; i < dev->data->nb_rx_queues; i++) { + dev->data->rx_queue_state[i] = RTE_ETH_QUEUE_STATE_STARTED; + dev->data->tx_queue_state[i] = RTE_ETH_QUEUE_STATE_STARTED; + } + + return 0; +} + +static int +rtap_dev_stop(struct rte_eth_dev *dev) +{ + int *fds = dev->process_private; + + dev->data->dev_link.link_status = RTE_ETH_LINK_DOWN; + + for (uint16_t i = 0; i < dev->data->nb_rx_queues; i++) { + dev->data->rx_queue_state[i] = RTE_ETH_QUEUE_STATE_STOPPED; + dev->data->tx_queue_state[i] = RTE_ETH_QUEUE_STATE_STOPPED; + } + + if (rte_eal_process_type() == RTE_PROC_PRIMARY) { + for (uint16_t i = 0; i < RTE_MAX_QUEUES_PER_PORT; i++) { + if (fds[i] == -1) + continue; + + close(fds[i]); + fds[i] = -1; + } + } + + return 0; +} + +static int +rtap_dev_configure(struct rte_eth_dev *dev) +{ + struct rtap_pmd *pmd = dev->data->dev_private; + + /* rx/tx must be paired */ + if (dev->data->nb_rx_queues != dev->data->nb_tx_queues) + return -EINVAL; + + if (ioctl(pmd->keep_fd, TUNSETOFFLOAD, 0) != 0) { + PMD_LOG(ERR, "ioctl(TUNSETOFFLOAD) failed: %s", strerror(errno)); + return -1; + } + + return 0; +} + static int rtap_dev_close(struct rte_eth_dev *dev) { struct rtap_pmd *pmd = dev->data->dev_private; + int *fds = dev->process_private; PMD_LOG(INFO, "Closing %s", pmd->ifname); + /* Release all io_uring queues (calls rx/tx_queue_release for each) */ + rte_eth_dev_internal_reset(dev); + + /* Close any remaining queue fds (each process owns its own set) */ + for (uint16_t i = 0; i < RTE_MAX_QUEUES_PER_PORT; i++) { + if (fds[i] == -1) + continue; + PMD_LOG(DEBUG, "Closed queue %u fd %d", i, fds[i]); + close(fds[i]); + fds[i] = -1; + } + if (rte_eal_process_type() == RTE_PROC_PRIMARY) { /* mac_addrs must not be freed alone because part of dev_private */ dev->data->mac_addrs = NULL; @@ -63,10 +190,96 @@ rtap_dev_close(struct rte_eth_dev *dev) return 0; } +/* Setup another fd to TAP device for the queue */ +int +rtap_queue_open(struct rte_eth_dev *dev, uint16_t queue_id) +{ + struct rtap_pmd *pmd = dev->data->dev_private; + int *fds = dev->process_private; + + if (fds[queue_id] != -1) { + PMD_LOG(DEBUG, "queue %u already has fd %d", queue_id, fds[queue_id]); + return 0; /* already setup */ + } + + struct ifreq ifr = { 0 }; + int tap_fd = rtap_tap_open(pmd->ifname, &ifr, 0); + if (tap_fd < 0) { + PMD_LOG(ERR, "tap_open failed"); + return -1; + } + + PMD_LOG(DEBUG, "Opened %d for queue %u", tap_fd, queue_id); + fds[queue_id] = tap_fd; + return 0; +} + +void +rtap_queue_close(struct rte_eth_dev *dev, uint16_t queue_id) +{ + int *fds = dev->process_private; + int tap_fd = fds[queue_id]; + + if (tap_fd == -1) + return; /* already closed */ + PMD_LOG(DEBUG, "Closed queue %u fd %d", queue_id, tap_fd); + close(tap_fd); + fds[queue_id] = -1; +} + static const struct eth_dev_ops rtap_ops = { + .dev_start = rtap_dev_start, + .dev_stop = rtap_dev_stop, + .dev_configure = rtap_dev_configure, .dev_close = rtap_dev_close, }; +static int +rtap_create(struct rte_eth_dev *dev, const char *tap_name, uint8_t persist) +{ + struct rte_eth_dev_data *data = dev->data; + struct rtap_pmd *pmd = data->dev_private; + + pmd->keep_fd = -1; + + dev->dev_ops = &rtap_ops; + + /* Get the initial fd used to keep the tap device around */ + struct ifreq ifr = { 0 }; + pmd->keep_fd = rtap_tap_open(tap_name, &ifr, persist); + if (pmd->keep_fd < 0) + goto error; + + PMD_LOG(DEBUG, "Created %s keep_fd %d", ifr.ifr_name, pmd->keep_fd); + + /* Use name returned by kernel i.e if tap_name is rtap%d this will be rtap0 */ + strlcpy(pmd->ifname, ifr.ifr_name, IFNAMSIZ); + + /* Read the MAC address assigned by the kernel */ + if (ioctl(pmd->keep_fd, SIOCGIFHWADDR, &ifr) < 0) { + PMD_LOG_ERRNO(ERR, "Unable to get MAC address for %s", ifr.ifr_name); + goto error; + } + memcpy(&pmd->eth_addr, &ifr.ifr_hwaddr.sa_data, RTE_ETHER_ADDR_LEN); + data->mac_addrs = &pmd->eth_addr; + + /* Detach this instance, not used for traffic */ + ifr.ifr_flags = IFF_DETACH_QUEUE; + if (ioctl(pmd->keep_fd, TUNSETQUEUE, &ifr) < 0) { + PMD_LOG_ERRNO(ERR, "Unable to detach keep-alive queue for %s", ifr.ifr_name); + goto error; + } + + PMD_LOG(DEBUG, "%s setup", ifr.ifr_name); + + return 0; + +error: + if (pmd->keep_fd != -1) + close(pmd->keep_fd); + return -1; +} + static int rtap_parse_iface(const char *key __rte_unused, const char *value, void *extra_args) { @@ -129,7 +342,8 @@ rtap_probe(struct rte_vdev_device *vdev) eth_dev->process_private = fds; eth_dev->data->dev_flags |= RTE_ETH_DEV_AUTOFILL_QUEUE_XSTATS; - RTE_SET_USED(persist); /* used in later patches */ + if (rtap_create(eth_dev, tap_name, persist) < 0) + goto error; rte_eth_dev_probing_finish(eth_dev); rte_kvargs_free(kvlist); -- 2.51.0
