Add link state change (LSC) notification support using a netlink socket subscribed to RTMGRP_LINK events.
When enabled, the driver registers a netlink socket with the EAL interrupt handler. On receiving RTM_NEWLINK/RTM_DELLINK messages matching the interface ifindex, the driver updates link status and triggers RTE_ETH_EVENT_INTR_LSC callbacks. LSC is enabled in dev_start and disabled in dev_stop. Signed-off-by: Stephen Hemminger <[email protected]> --- doc/guides/nics/features/rtap.ini | 1 + drivers/net/rtap/meson.build | 1 + drivers/net/rtap/rtap.h | 4 ++ drivers/net/rtap/rtap_ethdev.c | 26 ++++++++- drivers/net/rtap/rtap_intr.c | 87 +++++++++++++++++++++++++++++++ 5 files changed, 118 insertions(+), 1 deletion(-) create mode 100644 drivers/net/rtap/rtap_intr.c diff --git a/doc/guides/nics/features/rtap.ini b/doc/guides/nics/features/rtap.ini index cfbd29ef08..fe0c88a8fc 100644 --- a/doc/guides/nics/features/rtap.ini +++ b/doc/guides/nics/features/rtap.ini @@ -5,6 +5,7 @@ ; [Features] Link status = Y +Link status event = Y MTU update = Y Promiscuous mode = Y Allmulticast mode = Y diff --git a/drivers/net/rtap/meson.build b/drivers/net/rtap/meson.build index ed0bcc1313..58943e035a 100644 --- a/drivers/net/rtap/meson.build +++ b/drivers/net/rtap/meson.build @@ -19,6 +19,7 @@ endif sources = files( 'rtap_ethdev.c', + 'rtap_intr.c', 'rtap_netlink.c', 'rtap_rxtx.c', ) diff --git a/drivers/net/rtap/rtap.h b/drivers/net/rtap/rtap.h index aeda7f3f25..2cc55c9667 100644 --- a/drivers/net/rtap/rtap.h +++ b/drivers/net/rtap/rtap.h @@ -61,6 +61,7 @@ struct rtap_pmd { int keep_fd; /* keep alive file descriptor */ int if_index; /* interface index */ int nlsk_fd; /* netlink control socket */ + struct rte_intr_handle *intr_handle; /* LSC interrupt handle */ struct rte_ether_addr eth_addr; /* address assigned by kernel */ uint64_t rx_drop_base; /* value of rx_dropped when reset */ @@ -98,4 +99,7 @@ int rtap_tx_queue_setup(struct rte_eth_dev *dev, uint16_t queue_id, const struct rte_eth_txconf *tx_conf); void rtap_tx_queue_release(struct rte_eth_dev *dev, uint16_t queue_id); +/* rtap_intr.c */ +int rtap_lsc_set(struct rte_eth_dev *dev, int set); + #endif /* _RTAP_H_ */ diff --git a/drivers/net/rtap/rtap_ethdev.c b/drivers/net/rtap/rtap_ethdev.c index 705d98323e..9c23ca2f16 100644 --- a/drivers/net/rtap/rtap_ethdev.c +++ b/drivers/net/rtap/rtap_ethdev.c @@ -214,11 +214,18 @@ rtap_macaddr_set(struct rte_eth_dev *dev, struct rte_ether_addr *addr) static int rtap_dev_start(struct rte_eth_dev *dev) { - int ret = rtap_set_link_up(dev); + int ret; + ret = rtap_lsc_set(dev, 1); if (ret != 0) return ret; + ret = rtap_set_link_up(dev); + if (ret != 0) { + rtap_lsc_set(dev, 0); + return ret; + } + 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; @@ -235,6 +242,7 @@ rtap_dev_stop(struct rte_eth_dev *dev) dev->data->dev_link.link_status = RTE_ETH_LINK_DOWN; + rtap_lsc_set(dev, 0); rtap_set_link_down(dev); for (uint16_t i = 0; i < dev->data->nb_rx_queues; i++) { @@ -435,6 +443,9 @@ rtap_dev_close(struct rte_eth_dev *dev) close(pmd->nlsk_fd); pmd->nlsk_fd = -1; } + + rte_intr_instance_free(pmd->intr_handle); + pmd->intr_handle = NULL; } free(dev->process_private); @@ -522,6 +533,17 @@ rtap_create(struct rte_eth_dev *dev, const char *tap_name, uint8_t persist) pmd->nlsk_fd = -1; pmd->rx_drop_base = 0; + /* Allocate interrupt instance for link state change events */ + pmd->intr_handle = rte_intr_instance_alloc(RTE_INTR_INSTANCE_F_SHARED); + if (pmd->intr_handle == NULL) { + PMD_LOG(ERR, "Failed to allocate intr handle"); + goto error; + } + rte_intr_type_set(pmd->intr_handle, RTE_INTR_HANDLE_EXT); + rte_intr_fd_set(pmd->intr_handle, -1); + dev->intr_handle = pmd->intr_handle; + data->dev_flags |= RTE_ETH_DEV_INTR_LSC; + dev->dev_ops = &rtap_ops; /* Get the initial fd used to keep the tap device around */ @@ -571,6 +593,8 @@ rtap_create(struct rte_eth_dev *dev, const char *tap_name, uint8_t persist) close(pmd->nlsk_fd); if (pmd->keep_fd != -1) close(pmd->keep_fd); + rte_intr_instance_free(pmd->intr_handle); + pmd->intr_handle = NULL; return -1; } diff --git a/drivers/net/rtap/rtap_intr.c b/drivers/net/rtap/rtap_intr.c new file mode 100644 index 0000000000..6cdfb412c3 --- /dev/null +++ b/drivers/net/rtap/rtap_intr.c @@ -0,0 +1,87 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * Copyright (c) 2026 Stephen Hemminger + */ + +#include <errno.h> +#include <stdbool.h> +#include <unistd.h> +#include <linux/rtnetlink.h> + +#include <rte_cycles.h> +#include <rte_ethdev.h> +#include <rte_errno.h> +#include <ethdev_driver.h> +#include <rte_interrupts.h> + +#include "rtap.h" + +/* Interrupt handler called by EAL when netlink socket is readable */ +static void +rtap_lsc_handler(void *cb_arg) +{ + struct rte_eth_dev *dev = cb_arg; + struct rtap_pmd *pmd = dev->data->dev_private; + int fd = rte_intr_fd_get(pmd->intr_handle); + + if (fd >= 0) + rtap_nl_recv(fd, dev); +} + +/* + * Enable or disable link state change interrupt. + * When enabled, creates a netlink socket subscribed to RTMGRP_LINK + * and registers it with the EAL interrupt handler. + */ +int +rtap_lsc_set(struct rte_eth_dev *dev, int set) +{ + struct rtap_pmd *pmd = dev->data->dev_private; + unsigned int retry = 10; + int ret; + + /* If LSC not configured, just disable if active */ + if (!dev->data->dev_conf.intr_conf.lsc) { + if (rte_intr_fd_get(pmd->intr_handle) != -1) + goto disable; + return 0; + } + + if (set) { + int fd = rtap_nl_open(RTMGRP_LINK); + if (fd < 0) + return -1; + + rte_intr_fd_set(pmd->intr_handle, fd); + ret = rte_intr_callback_register(pmd->intr_handle, + rtap_lsc_handler, dev); + if (ret < 0) { + PMD_LOG(ERR, "Failed to register LSC callback: %s", + rte_strerror(-ret)); + close(fd); + rte_intr_fd_set(pmd->intr_handle, -1); + return ret; + } + return 0; + } + +disable: + do { + ret = rte_intr_callback_unregister(pmd->intr_handle, + rtap_lsc_handler, dev); + if (ret >= 0) { + break; + } else if (ret == -EAGAIN && retry-- > 0) { + rte_delay_ms(100); + } else { + PMD_LOG(ERR, "LSC callback unregister failed: %d", ret); + break; + } + } while (true); + + if (rte_intr_fd_get(pmd->intr_handle) >= 0) { + close(rte_intr_fd_get(pmd->intr_handle)); + rte_intr_fd_set(pmd->intr_handle, -1); + } + + return 0; +} -- 2.51.0
