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[204.195.96.226]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4362972fc26sm26448426f8f.22.2026.02.09.10.41.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Feb 2026 10:41:01 -0800 (PST) From: Stephen Hemminger To: dev@dpdk.org Cc: Stephen Hemminger Subject: [PATCH v5 07/10] net/rtap: add link state change interrupt Date: Mon, 9 Feb 2026 10:39:06 -0800 Message-ID: <20260209184045.132774-8-stephen@networkplumber.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260209184045.132774-1-stephen@networkplumber.org> References: <20241210212757.83490-1-stephen@networkplumber.org> <20260209184045.132774-1-stephen@networkplumber.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Add link state change (LSC) notification support using a netlink socket subscribed to RTMGRP_LINK events. When LSC is enabled in the device configuration, the driver: - Creates a NETLINK_ROUTE socket filtering for RTM_NEWLINK and RTM_DELLINK messages - Registers the socket fd with the EAL interrupt handler - On interrupt, drains all pending netlink messages and updates the link status for matching interface index changes The interrupt is enabled during dev_start and disabled during dev_stop, with proper cleanup of the netlink socket and EAL callback registration. Signed-off-by: Stephen Hemminger --- doc/guides/nics/features/rtap.ini | 1 + drivers/net/rtap/meson.build | 1 + drivers/net/rtap/rtap.h | 5 + drivers/net/rtap/rtap_ethdev.c | 36 +++++++- drivers/net/rtap/rtap_intr.c | 147 ++++++++++++++++++++++++++++++ 5 files changed, 187 insertions(+), 3 deletions(-) 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 b8eaa805fe..36a14e9696 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 8e2b15f382..86d400323c 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_rxtx.c', ) diff --git a/drivers/net/rtap/rtap.h b/drivers/net/rtap/rtap.h index 99f413f001..f73b5e317d 100644 --- a/drivers/net/rtap/rtap.h +++ b/drivers/net/rtap/rtap.h @@ -13,6 +13,7 @@ #include #include +#include #include @@ -62,6 +63,7 @@ struct rtap_tx_queue { struct rtap_pmd { int keep_fd; /* keep alive file descriptor */ + struct rte_intr_handle *intr_handle; /* LSC interrupt handle */ char ifname[IFNAMSIZ]; /* name assigned by kernel */ struct rte_ether_addr eth_addr; /* address assigned by kernel */ @@ -86,4 +88,7 @@ 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 277a280772..8c22021655 100644 --- a/drivers/net/rtap/rtap_ethdev.c +++ b/drivers/net/rtap/rtap_ethdev.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -141,11 +142,16 @@ rtap_change_flags(struct rte_eth_dev *dev, uint32_t flags, uint32_t mask) ifr.ifr_flags |= flags; ret = ioctl(sock, SIOCSIFFLAGS, &ifr); - if (ret < 0) + if (ret < 0) { PMD_LOG_ERRNO(ERR, "Unable to set flags for %s", ifr.ifr_name); + goto error; + } + close(sock); + return 0; error: + ret = -errno; close(sock); - return (ret < 0) ? -errno : 0; + return ret; } static int @@ -277,11 +283,18 @@ 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; @@ -298,6 +311,7 @@ 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++) { @@ -508,6 +522,9 @@ rtap_dev_close(struct rte_eth_dev *dev) close(pmd->keep_fd); pmd->keep_fd = -1; } + + rte_intr_instance_free(pmd->intr_handle); + pmd->intr_handle = NULL; } free(dev->process_private); @@ -585,6 +602,17 @@ rtap_create(struct rte_eth_dev *dev, const char *tap_name, uint8_t persist) pmd->keep_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 */ @@ -623,6 +651,8 @@ rtap_create(struct rte_eth_dev *dev, const char *tap_name, uint8_t persist) error: 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..8a27b811e1 --- /dev/null +++ b/drivers/net/rtap/rtap_intr.c @@ -0,0 +1,147 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * Copyright (c) 2026 Stephen Hemminger + */ + +#include +#include +#include +#include +#include +#include + +#include + +#include "rtap.h" + +/* + * Create a netlink socket subscribed to link state change events. + * Returns socket fd or -1 on failure. + */ +static int +rtap_netlink_init(unsigned int groups) +{ + int fd; + struct sockaddr_nl sa = { + .nl_family = AF_NETLINK, + .nl_groups = groups, + }; + + fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK, + NETLINK_ROUTE); + if (fd < 0) { + PMD_LOG_ERRNO(ERR, "netlink socket"); + return -1; + } + + if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { + PMD_LOG_ERRNO(ERR, "netlink bind"); + close(fd); + return -1; + } + + return fd; +} + +/* + * Drain all pending netlink messages from socket. + * For each RTM_NEWLINK/RTM_DELLINK that matches our interface, + * update link status. + */ +static void +rtap_netlink_recv(int fd, struct rte_eth_dev *dev) +{ + struct rtap_pmd *pmd = dev->data->dev_private; + unsigned int if_index = if_nametoindex(pmd->ifname); + char buf[4096]; + ssize_t len; + + while ((len = recv(fd, buf, sizeof(buf), 0)) > 0) { + for (struct nlmsghdr *nh = (struct nlmsghdr *)buf; + NLMSG_OK(nh, (unsigned int)len); + nh = NLMSG_NEXT(nh, len)) { + struct ifinfomsg *ifi; + + if (nh->nlmsg_type != RTM_NEWLINK && + nh->nlmsg_type != RTM_DELLINK) + continue; + + ifi = NLMSG_DATA(nh); + if ((unsigned int)ifi->ifi_index != if_index) + continue; + + /* Link state changed for our interface */ + rtap_link_update(dev, 0); + } + } +} + +/* 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_netlink_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; + 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_netlink_init(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: + unsigned int retry = 10; + do { + ret = rte_intr_callback_unregister(pmd->intr_handle, + rtap_lsc_handler, dev); + if (ret >= 0) + break; + 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