[dpdk-dev] [PATCH V18 3/4] eal/linux: uevent parse and process

[Jeff Guo]

In order to handle the uevent which has been detected from the kernel
side, add uevent parse and process function to translate the uevent into
device event, which user has subscribed to monitor.

Signed-off-by: Jeff Guo <jia.guo at intel.com>
---
v18->v17:
refine socket configuration.
---
 lib/librte_eal/linuxapp/eal/eal_dev.c | 178 +++++++++++++++++++++++++++++++++-
 1 file changed, 176 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c b/lib/librte_eal/linuxapp/eal/eal_dev.c
index 9c8d1a0..9f2ee40 100644
--- a/lib/librte_eal/linuxapp/eal/eal_dev.c
+++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
@@ -2,21 +2,195 @@
  * Copyright(c) 2018 Intel Corporation
  */
 
+#include <string.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <linux/netlink.h>
+
 #include <rte_log.h>
 #include <rte_compat.h>
 #include <rte_dev.h>
+#include <rte_malloc.h>
+#include <rte_interrupts.h>
+
+#include "eal_private.h"
+
+static struct rte_intr_handle intr_handle = {.fd = -1 };
+static bool monitor_started;
+
+#define EAL_UEV_MSG_LEN 4096
+#define EAL_UEV_MSG_ELEM_LEN 128
+
+/* identify the system layer which event exposure from */
+enum eal_dev_event_subsystem {
+	EAL_DEV_EVENT_SUBSYSTEM_PCI, /* PCI bus device event */
+	EAL_DEV_EVENT_SUBSYSTEM_UIO, /* UIO driver device event */
+	EAL_DEV_EVENT_SUBSYSTEM_VFIO, /* VFIO driver device event */
+	EAL_DEV_EVENT_SUBSYSTEM_MAX
+};
+
+static int
+dev_uev_socket_fd_create(void)
+{
+	struct sockaddr_nl addr;
+	int ret;
+
+	intr_handle.fd = socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC |
+			SOCK_NONBLOCK,
+			NETLINK_KOBJECT_UEVENT);
+	if (intr_handle.fd < 0) {
+		RTE_LOG(ERR, EAL, "create uevent fd failed.\n");
+		return -1;
+	}
+
+	memset(&addr, 0, sizeof(addr));
+	addr.nl_family = AF_NETLINK;
+	addr.nl_pid = 0;
+	addr.nl_groups = 0xffffffff;
+
+	ret = bind(intr_handle.fd, (struct sockaddr *) &addr, sizeof(addr));
+	if (ret < 0) {
+		RTE_LOG(ERR, EAL, "Failed to bind socket for netlink fd.\n");
+		goto err;
+	}
+
+	return 0;
+err:
+	close(intr_handle.fd);
+	return ret;
+}
+
+static void
+dev_uev_parse(const char *buf, struct rte_dev_event *event, int length)
+{
+	char action[EAL_UEV_MSG_ELEM_LEN];
+	char subsystem[EAL_UEV_MSG_ELEM_LEN];
+	char pci_slot_name[EAL_UEV_MSG_ELEM_LEN];
+	int i = 0;
+
+	memset(action, 0, EAL_UEV_MSG_ELEM_LEN);
+	memset(subsystem, 0, EAL_UEV_MSG_ELEM_LEN);
+	memset(pci_slot_name, 0, EAL_UEV_MSG_ELEM_LEN);
+
+	while (i < length) {
+		for (; i < length; i++) {
+			if (*buf)
+				break;
+			buf++;
+		}
+		if (!strncmp(buf, "ACTION=", 7)) {
+			buf += 7;
+			i += 7;
+			snprintf(action, sizeof(action), "%s", buf);
+		} else if (!strncmp(buf, "SUBSYSTEM=", 10)) {
+			buf += 10;
+			i += 10;
+			snprintf(subsystem, sizeof(subsystem), "%s", buf);
+		} else if (!strncmp(buf, "PCI_SLOT_NAME=", 14)) {
+			buf += 14;
+			i += 14;
+			snprintf(pci_slot_name, sizeof(subsystem), "%s", buf);
+			event->devname = strdup(pci_slot_name);
+		}
+		for (; i < length; i++) {
+			if (*buf == '\0')
+				break;
+			buf++;
+		}
+	}
+
+	if (!strncmp(subsystem, "uio", 3))
+		event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_UIO;
+	else if (!strncmp(subsystem, "pci", 3))
+		event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_PCI;
+	else if (!strncmp(subsystem, "vfio", 4))
+		event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_VFIO;
+	if (!strncmp(action, "add", 3))
+		event->type = RTE_DEV_EVENT_ADD;
+	if (!strncmp(action, "remove", 6))
+		event->type = RTE_DEV_EVENT_REMOVE;
+}
+
+static int
+dev_uev_receive(int fd, struct rte_dev_event *uevent)
+{
+	int ret;
+	char buf[EAL_UEV_MSG_LEN];
+
+	memset(uevent, 0, sizeof(struct rte_dev_event));
+	memset(buf, 0, EAL_UEV_MSG_LEN);
+
+	ret = recv(fd, buf, EAL_UEV_MSG_LEN, MSG_DONTWAIT);
+	if (ret < 0) {
+		RTE_LOG(ERR, EAL,
+			"Socket read error(%d): %s.\n",
+			errno, strerror(errno));
+		return -1;
+	} else if (ret == 0)
+		/* connection closed */
+		return -1;
+
+	dev_uev_parse(buf, uevent, EAL_UEV_MSG_LEN);
+
+	return 0;
+}
+
+static void
+dev_uev_process(__rte_unused void *param)
+{
+	struct rte_dev_event uevent;
+
+	if (dev_uev_receive(intr_handle.fd, &uevent))
+		return;
 
+	if (uevent.devname)
+		dev_callback_process(uevent.devname, uevent.type);
+}
 
 int __rte_experimental
 rte_dev_event_monitor_start(void)
 {
-	/* TODO: start uevent monitor for linux */
+	int ret;
+
+	if (monitor_started)
+		return 0;
+
+	ret = dev_uev_socket_fd_create();
+	if (ret) {
+		RTE_LOG(ERR, EAL, "error create device event fd.\n");
+		return -1;
+	}
+
+	intr_handle.type = RTE_INTR_HANDLE_DEV_EVENT;
+	ret = rte_intr_callback_register(&intr_handle, dev_uev_process, NULL);
+
+	if (ret) {
+		RTE_LOG(ERR, EAL, "fail to register uevent callback.\n");
+		return -1;
+	}
+
+	monitor_started = true;
+
 	return 0;
 }
 
 int __rte_experimental
 rte_dev_event_monitor_stop(void)
 {
-	/* TODO: stop uevent monitor for linux */
+	int ret;
+
+	if (!monitor_started)
+		return 0;
+
+	ret = rte_intr_callback_unregister(&intr_handle, dev_uev_process,
+					   (void *)-1);
+	if (ret < 0) {
+		RTE_LOG(ERR, EAL, "fail to unregister uevent callback.\n");
+		return ret;
+	}
+
+	close(intr_handle.fd);
+	intr_handle.fd = -1;
+	monitor_started = false;
 	return 0;
 }
-- 
2.7.4