discover: Add network handling

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

7 files changed, 451 insertions, 0 deletions

diff --git a/configure.ac.in b/configure.ac.in
index bfc2572..1d6703b 100644
--- a/configure.ac.in
+++ b/configure.ac.in
@@ -195,6 +195,8 @@ DEFINE_HOST_PROG(SFTP, sftp, [/usr/bin/sftp])
 DEFINE_HOST_PROG(TFTP, tftp, [/usr/bin/tftp])
 DEFINE_HOST_PROG(UMOUNT, umount, [/bin/umount])
 DEFINE_HOST_PROG(WGET, wget, [/usr/bin/wget])
+DEFINE_HOST_PROG(IP, ip, [/sbin/ip])
+DEFINE_HOST_PROG(UDHCPC, udhcpc, [/sbin/udhcpc])
 
 default_cflags="--std=gnu99 -g \
 	-Wall -W -Wunused -Wstrict-prototypes -Wmissing-prototypes \
diff --git a/discover/Makefile.am b/discover/Makefile.am
index ddf37ef..a449818 100644
--- a/discover/Makefile.am
+++ b/discover/Makefile.am
@@ -58,6 +58,8 @@ pb_discover_SOURCES = \
 	parser-utils.h \
 	pb-discover.c \
 	pb-discover.h \
+	network.c \
+	network.h \
 	udev.c \
 	udev.h \
 	user-event.c \
diff --git a/discover/network.c b/discover/network.c
new file mode 100644
index 0000000..4a4f932
--- /dev/null
+++ b/discover/network.c
@@ -0,0 +1,426 @@
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <linux/if.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include <log/log.h>
+#include <list/list.h>
+#include <talloc/talloc.h>
+#include <waiter/waiter.h>
+#include <pb-config/pb-config.h>
+#include <system/system.h>
+
+#include "network.h"
+
+#define HWADDR_SIZE	6
+#define PIDFILE_BASE	(LOCAL_STATE_DIR "/petitboot/")
+
+#define for_each_nlmsg(buf, nlmsg, len) \
+	for (nlmsg = (struct nlmsghdr *)buf; \
+		NLMSG_OK(nlmsg, len) && nlmsg->nlmsg_type != NLMSG_DONE; \
+		nlmsg = NLMSG_NEXT(nlmsg, len))
+
+#define for_each_rta(buf, rta, attrlen) \
+	for (rta = (struct rtattr *)(buf); RTA_OK(rta, attrlen); \
+			rta = RTA_NEXT(rta, attrlen))
+
+
+struct interface {
+	int	ifindex;
+	char	name[IFNAMSIZ];
+	uint8_t	hwaddr[HWADDR_SIZE];
+
+	enum {
+		IFSTATE_NEW,
+		IFSTATE_UP_WAITING_LINK,
+		IFSTATE_CONFIGURED,
+		IFSTATE_IGNORED,
+	} state;
+
+	struct list_item list;
+};
+
+struct network {
+	struct list	interfaces;
+	struct waiter	*waiter;
+	int		netlink_sd;
+	bool		manual_config;
+	bool		dry_run;
+};
+
+static const struct network_config *find_config_by_hwaddr(
+		uint8_t *hwaddr)
+{
+	const struct config *config;
+	int i;
+
+	config = config_get();
+	if (!config)
+		return NULL;
+
+	for (i = 0; i < config->n_network_configs; i++) {
+		struct network_config *netconf = config->network_configs[i];
+
+		if (!memcmp(netconf->hwaddr, hwaddr, HWADDR_SIZE))
+			return netconf;
+	}
+
+	return NULL;
+}
+
+static struct interface *find_interface_by_ifindex(struct network *network,
+		int ifindex)
+{
+	struct interface *interface;
+
+	list_for_each_entry(&network->interfaces, interface, list)
+		if (interface->ifindex == ifindex)
+			return interface;
+
+	return NULL;
+}
+
+static int network_init_netlink(struct network *network)
+{
+	struct sockaddr_nl addr;
+	int rc;
+
+	memset(&addr, 0, sizeof(addr));
+	addr.nl_family = AF_NETLINK;
+	addr.nl_groups = RTMGRP_LINK;
+
+	network->netlink_sd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
+	if (network->netlink_sd < 0) {
+		perror("socket(AF_NETLINK)");
+		return -1;
+	}
+
+	rc = bind(network->netlink_sd, (struct sockaddr *)&addr, sizeof(addr));
+	if (rc) {
+		perror("bind(sockaddr_nl)");
+		close(network->netlink_sd);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int network_send_link_query(struct network *network)
+{
+	int rc;
+	struct {
+		struct nlmsghdr nlmsg;
+		struct rtgenmsg rtmsg;
+	} msg;
+
+	memset(&msg, 0, sizeof(msg));
+
+	msg.nlmsg.nlmsg_len = sizeof(msg);
+	msg.nlmsg.nlmsg_type = RTM_GETLINK;
+	msg.nlmsg.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
+	msg.nlmsg.nlmsg_seq = 0;
+	msg.nlmsg.nlmsg_pid = 0;
+	msg.rtmsg.rtgen_family = AF_UNSPEC;
+
+	rc = send(network->netlink_sd, &msg, sizeof(msg), MSG_NOSIGNAL);
+	if (rc != sizeof(msg))
+		return -1;
+
+	return 0;
+}
+
+static int interface_up(struct network *network, struct interface *interface)
+{
+	int rc;
+	const char *argv[] = {
+		pb_system_apps.ip,
+		"link",
+		"set",
+		interface->name,
+		"up",
+		NULL,
+	};
+
+	rc = pb_run_cmd(argv, 1, network->dry_run);
+	if (rc) {
+		pb_log("failed to bring interface %s up\n", interface->name);
+		return -1;
+	}
+	return 0;
+}
+
+static void configure_interface_dhcp(struct network *network,
+		struct interface *interface)
+{
+	char pidfile[256];
+	const char *argv[] = {
+		pb_system_apps.udhcpc,
+		"-R",
+		"-n",
+		"-p", pidfile,
+		"-i", interface->name,
+		NULL,
+	};
+	snprintf(pidfile, sizeof(pidfile), "%s/udhcpc-%s.pid",
+			PIDFILE_BASE, interface->name);
+
+	pb_run_cmd(argv, 0, network->dry_run);
+	return;
+}
+
+static void configure_interface_static(struct network *network,
+		struct interface *interface,
+		const struct network_config *config)
+{
+	const char *addr_argv[] = {
+		pb_system_apps.ip,
+		"address",
+		"add",
+		config->static_config.address,
+		"dev",
+		interface->name,
+		NULL,
+	};
+	const char *route_argv[] = {
+		pb_system_apps.ip,
+		"route",
+		"add",
+		"default",
+		"via",
+		config->static_config.gateway,
+		NULL,
+	};
+	int rc;
+
+
+	rc = pb_run_cmd(addr_argv, 1, network->dry_run);
+	if (rc) {
+		pb_log("failed to add address %s to interface %s\n",
+				config->static_config.address,
+				interface->name);
+		return;
+	}
+
+	/* we need the interface up before we can route through it */
+	rc = interface_up(network, interface);
+	if (rc)
+		return;
+
+	if (config->static_config.gateway)
+		rc = pb_run_cmd(route_argv, 1, network->dry_run);
+
+	if (rc) {
+		pb_log("failed to add default route %s on interface %s\n",
+				config->static_config.gateway,
+				interface->name);
+	}
+
+	return;
+}
+
+static void configure_interface(struct network *network,
+		struct interface *interface, bool up, bool link)
+{
+	const struct network_config *config = NULL;
+
+	if (interface->state == IFSTATE_IGNORED)
+		return;
+
+	/* old interface? check that we're still up and running */
+	if (interface->state == IFSTATE_CONFIGURED) {
+		if (!up)
+			interface->state = IFSTATE_NEW;
+		else if (!link)
+			interface->state = IFSTATE_UP_WAITING_LINK;
+		else
+			return;
+	}
+
+	/* always up the lookback, no other handling required */
+	if (!strcmp(interface->name, "lo")) {
+		if (interface->state == IFSTATE_NEW)
+			interface_up(network, interface);
+		interface->state = IFSTATE_CONFIGURED;
+		return;
+	}
+
+	config = find_config_by_hwaddr(interface->hwaddr);
+	if (config && config->ignore) {
+		pb_log("network: ignoring interface %s\n", interface->name);
+		interface->state = IFSTATE_IGNORED;
+		return;
+	}
+
+	/* if we're in manual config mode, we need an interface configuration */
+	if (network->manual_config && !config) {
+		interface->state = IFSTATE_IGNORED;
+		pb_log("network: skipping %s: manual config mode, "
+				"but no config for this interface\n",
+				interface->name);
+		return;
+	}
+
+	/* new interface? bring up to the point so we can detect a link */
+	if (interface->state == IFSTATE_NEW) {
+		if (!up) {
+			interface_up(network, interface);
+			pb_log("network: bringing up interface %s\n",
+					interface->name);
+			return;
+
+		} else if (!link) {
+			interface->state = IFSTATE_UP_WAITING_LINK;
+		}
+	}
+
+	/* no link? wait for a notification */
+	if (interface->state == IFSTATE_UP_WAITING_LINK && !link)
+		return;
+
+	pb_log("network: configuring interface %s\n", interface->name);
+
+	if (!config || config->method == CONFIG_METHOD_DHCP) {
+		configure_interface_dhcp(network, interface);
+
+	} else if (config->method == CONFIG_METHOD_STATIC) {
+		configure_interface_static(network, interface, config);
+	}
+}
+
+static int network_handle_nlmsg(struct network *network, struct nlmsghdr *nlmsg)
+{
+	bool have_ifaddr, have_ifname;
+	struct interface *interface;
+	struct ifinfomsg *info;
+	struct rtattr *attr;
+	uint8_t ifaddr[6];
+	char ifname[IFNAMSIZ+1];
+	int attrlen, type;
+
+
+	/* we're only interested in NEWLINK messages */
+	type = nlmsg->nlmsg_type;
+	if (!(type == RTM_NEWLINK || type == RTM_DELLINK))
+		return 0;
+
+	info = NLMSG_DATA(nlmsg);
+
+	have_ifaddr = have_ifname = false;
+
+	attrlen = nlmsg->nlmsg_len - sizeof(*info);
+
+	/* extract the interface name and hardware address attributes */
+	for_each_rta(info + 1, attr, attrlen) {
+		void *data = RTA_DATA(attr);
+
+		switch (attr->rta_type) {
+		case IFLA_ADDRESS:
+			memcpy(ifaddr, data, sizeof(ifaddr));
+			have_ifaddr = true;
+			break;
+
+		case IFLA_IFNAME:
+			strncpy(ifname, data, IFNAMSIZ);
+			have_ifname = true;
+			break;
+		}
+	}
+
+	if (!have_ifaddr || !have_ifname)
+		return -1;
+
+	if (type == RTM_DELLINK) {
+		interface = find_interface_by_ifindex(network, info->ifi_index);
+		if (!interface)
+			return 0;
+		pb_log("network: interface %s removed\n", interface->name);
+		list_remove(&interface->list);
+		talloc_free(interface);
+		return 0;
+	}
+
+
+	interface = find_interface_by_ifindex(network, info->ifi_index);
+	if (!interface) {
+		interface = talloc_zero(network, struct interface);
+		interface->ifindex = info->ifi_index;
+		interface->state = IFSTATE_NEW;
+		memcpy(interface->hwaddr, ifaddr, sizeof(interface->hwaddr));
+		strncpy(interface->name, ifname, sizeof(interface->name) - 1);
+	}
+
+	configure_interface(network, interface,
+			info->ifi_flags & IFF_UP,
+			info->ifi_flags & IFF_LOWER_UP);
+
+	return 0;
+}
+
+static int network_netlink_process(void *arg)
+{
+	struct network *network = arg;
+	struct nlmsghdr *nlmsg;
+	unsigned int len;
+	char buf[4096];
+	int rc;
+
+	rc = recv(network->netlink_sd, buf, sizeof(buf), 0);
+	if (rc < 0) {
+		perror("netlink recv");
+		return -1;
+	}
+
+	len = rc;
+
+	for_each_nlmsg(buf, nlmsg, len)
+		network_handle_nlmsg(network, nlmsg);
+
+	return 0;
+}
+
+struct network *network_init(void *ctx, struct waitset *waitset, bool dry_run)
+{
+	struct network *network;
+	int rc;
+
+	network = talloc(ctx, struct network);
+	list_init(&network->interfaces);
+	network->manual_config = false;
+	network->dry_run = dry_run;
+
+	rc = network_init_netlink(network);
+	if (rc)
+		goto err;
+
+	network->waiter = waiter_register_io(waitset, network->netlink_sd,
+			WAIT_IN, network_netlink_process, network);
+
+	if (!network->waiter)
+		goto err;
+
+	rc = network_send_link_query(network);
+	if (rc)
+		goto err;
+
+	return network;
+
+err:
+	network_shutdown(network);
+	return NULL;
+}
+
+
+int network_shutdown(struct network *network)
+{
+	if (network->waiter)
+		waiter_remove(network->waiter);
+
+	close(network->netlink_sd);
+	talloc_free(network);
+	return 0;
+}
diff --git a/discover/network.h b/discover/network.h
new file mode 100644
index 0000000..c90af40
--- /dev/null
+++ b/discover/network.h
@@ -0,0 +1,11 @@
+#ifndef NETWORK_H
+#define NETWORK_H
+
+struct network;
+struct waitset;
+
+struct network *network_init(void *ctx, struct waitset *waitset, bool dry_run);
+int network_shutdown(struct network *network);
+
+#endif /* NETWORK_H */
+
diff --git a/discover/pb-discover.c b/discover/pb-discover.c
index fac1c9d..986401d 100644
--- a/discover/pb-discover.c
+++ b/discover/pb-discover.c
@@ -17,6 +17,7 @@
 #include "user-event.h"
 #include "discover-server.h"
 #include "device-handler.h"
+#include "network.h"
 
 static void print_version(void)
 {
@@ -108,6 +109,7 @@ int main(int argc, char *argv[])
 {
 	struct device_handler *handler;
 	struct discover_server *server;
+	struct network *network;
 	struct waitset *waitset;
 	struct opts opts;
 	struct pb_udev *udev;
@@ -154,6 +156,10 @@ int main(int argc, char *argv[])
 	if (!server)
 		return EXIT_FAILURE;
 
+	network = network_init(server, waitset, opts.dry_run == opt_yes);
+	if (!network)
+		return EXIT_FAILURE;
+
 	handler = device_handler_init(server, waitset, opts.dry_run == opt_yes);
 	if (!handler)
 		return EXIT_FAILURE;
diff --git a/lib/system/system.c b/lib/system/system.c
index 13dc146..dbdef46 100644
--- a/lib/system/system.c
+++ b/lib/system/system.c
@@ -26,6 +26,8 @@ const struct pb_system_apps pb_system_apps = {
 	.tftp		= HOST_PROG_TFTP,
 	.umount		= HOST_PROG_UMOUNT,
 	.wget		= HOST_PROG_WGET,
+	.ip		= HOST_PROG_IP,
+	.udhcpc		= HOST_PROG_UDHCPC,
 };
 
 int pb_mkdir_recursive(const char *dir)
diff --git a/lib/system/system.h b/lib/system/system.h
index f8f18a3..271c435 100644
--- a/lib/system/system.h
+++ b/lib/system/system.h
@@ -11,6 +11,8 @@ struct pb_system_apps {
 	const char *tftp;
 	const char *umount;
 	const char *wget;
+	const char *ip;
+	const char *udhcpc;
 };
 
 extern const struct pb_system_apps pb_system_apps;