1 files changed, 335 insertions, 0 deletions
diff --git a/src/iftable.c b/src/iftable.c
new file mode 100644
index 0000000..0325335
--- /dev/null
+++ b/src/iftable.c
@@ -0,0 +1,335 @@
+/* iftable - table of network interfaces
+ *
+ * (C) 2004 by Astaro AG, written by Harald Welte <hwelte@astaro.com>
+ * (C) 2008 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This software is Free Software and licensed under GNU GPLv2. 
+ */
+
+/* IFINDEX handling */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <assert.h>
+
+#include <linux/netdevice.h>
+
+#include <libnfnetlink/libnfnetlink.h>
+#include "rtnl.h"
+#include "linux_list.h"
+
+struct ifindex_node {
+	struct list_head head;
+
+	u_int32_t	index;
+	u_int32_t	type;
+	u_int32_t	alen;
+	u_int32_t	flags;
+	char		addr[8];
+	char		name[16];
+};
+
+struct nlif_handle {
+	struct list_head ifindex_hash[16];
+	struct rtnl_handle *rtnl_handle;
+	struct rtnl_handler ifadd_handler;
+	struct rtnl_handler ifdel_handler;
+};
+
+/* iftable_add - Add/Update an entry to/in the interface table
+ * @n:		netlink message header of a RTM_NEWLINK message
+ * @arg:	not used
+ *
+ * This function adds/updates an entry in the intrface table.
+ * Returns -1 on error, 1 on success.
+ */
+static int iftable_add(struct nlmsghdr *n, void *arg)
+{
+	unsigned int hash, found = 0;
+	struct ifinfomsg *ifi_msg = NLMSG_DATA(n);
+	struct ifindex_node *this;
+	struct rtattr *cb[IFLA_MAX+1];
+	struct nlif_handle *h = arg;
+
+	if (n->nlmsg_type != RTM_NEWLINK)
+		return -1;
+
+	if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi_msg)))
+		return -1;
+
+	rtnl_parse_rtattr(cb, IFLA_MAX, IFLA_RTA(ifi_msg), IFLA_PAYLOAD(n));
+
+	if (!cb[IFLA_IFNAME])
+		return -1;
+
+	hash = ifi_msg->ifi_index & 0xF;
+	list_for_each_entry(this, &h->ifindex_hash[hash], head) {
+		if (this->index == ifi_msg->ifi_index) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found) {
+		this = malloc(sizeof(*this));
+		if (!this)
+			return -1;
+
+		this->index = ifi_msg->ifi_index;
+	}
+
+	this->type = ifi_msg->ifi_type;
+	this->flags = ifi_msg->ifi_flags;
+	if (cb[IFLA_ADDRESS]) {
+		unsigned int alen;
+		this->alen = alen = RTA_PAYLOAD(cb[IFLA_ADDRESS]);
+		if (alen > sizeof(this->addr))
+			alen = sizeof(this->addr);
+		memcpy(this->addr, RTA_DATA(cb[IFLA_ADDRESS]), alen);
+	} else {
+		this->alen = 0;
+		memset(this->addr, 0, sizeof(this->addr));
+	}
+	strcpy(this->name, RTA_DATA(cb[IFLA_IFNAME]));
+
+	if (!found)
+		list_add(&this->head, &h->ifindex_hash[hash]);
+
+	return 1;
+}
+
+/* iftable_del - Delete an entry from the interface table
+ * @n:		netlink message header of a RTM_DELLINK nlmsg
+ * @arg:	not used
+ *
+ * Delete an entry from the interface table.  
+ * Returns -1 on error, 0 if no matching entry was found or 1 on success.
+ */
+static int iftable_del(struct nlmsghdr *n, void *arg)
+{
+	struct ifinfomsg *ifi_msg = NLMSG_DATA(n);
+	struct rtattr *cb[IFLA_MAX+1];
+	struct nlif_handle *h = arg;
+	struct ifindex_node *this, *tmp;
+	unsigned int hash;
+
+	if (n->nlmsg_type != RTM_DELLINK)
+		return -1;
+
+	if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi_msg)))
+		return -1;
+
+	rtnl_parse_rtattr(cb, IFLA_MAX, IFLA_RTA(ifi_msg), IFLA_PAYLOAD(n));
+
+	hash = ifi_msg->ifi_index & 0xF;
+	list_for_each_entry_safe(this, tmp, &h->ifindex_hash[hash], head) {
+		if (this->index == ifi_msg->ifi_index) {
+			list_del(&this->head);
+			free(this);
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+/** Get the name for an ifindex
+ *
+ * \param nlif_handle A pointer to a ::nlif_handle created
+ * \param index ifindex to be resolved
+ * \param name interface name, pass a buffer of IFNAMSIZ size
+ * \return -1 on error, 1 on success 
+ */
+int nlif_index2name(struct nlif_handle *h, 
+		    unsigned int index,
+		    char *name)
+{
+	unsigned int hash;
+	struct ifindex_node *this;
+
+	assert(h != NULL);
+	assert(name != NULL);
+
+	if (index == 0) {
+		strcpy(name, "*");
+		return 1;
+	}
+
+	hash = index & 0xF;
+	list_for_each_entry(this, &h->ifindex_hash[hash], head) {
+		if (this->index == index) {
+			strcpy(name, this->name);
+			return 1;
+		}
+	}
+
+	errno = ENOENT;
+	return -1;
+}
+
+/** Get the flags for an ifindex
+ *
+ * \param nlif_handle A pointer to a ::nlif_handle created
+ * \param index ifindex to be resolved
+ * \param flags pointer to variable used to store the interface flags
+ * \return -1 on error, 1 on success 
+ */
+int nlif_get_ifflags(const struct nlif_handle *h,
+		     unsigned int index,
+		     unsigned int *flags)
+{
+	unsigned int hash;
+	struct ifindex_node *this;
+
+	assert(h != NULL);
+	assert(flags != NULL);
+
+	if (index == 0) {
+		errno = ENOENT;
+		return -1;
+	}
+
+	hash = index & 0xF;
+	list_for_each_entry(this, &h->ifindex_hash[hash], head) {
+		if (this->index == index) {
+			*flags = this->flags;
+			return 1;
+		}
+	}
+	errno = ENOENT;
+	return -1;
+}
+
+/** Initialize interface table
+ *
+ * Initialize rtnl interface and interface table
+ * Call this before any nlif_* function
+ *
+ * \return file descriptor to netlink socket
+ */
+struct nlif_handle *nlif_open(void)
+{
+	int i;
+	struct nlif_handle *h;
+
+	h = calloc(1,  sizeof(struct nlif_handle));
+	if (h == NULL)
+		goto err;
+
+	for (i=0; i<16; i++)
+		INIT_LIST_HEAD(&h->ifindex_hash[i]);
+
+	h->ifadd_handler.nlmsg_type = RTM_NEWLINK;
+	h->ifadd_handler.handlefn = iftable_add;
+	h->ifadd_handler.arg = h;
+	h->ifdel_handler.nlmsg_type = RTM_DELLINK;
+	h->ifdel_handler.handlefn = iftable_del;
+	h->ifdel_handler.arg = h;
+
+	h->rtnl_handle = rtnl_open();
+	if (h->rtnl_handle == NULL)
+		goto err;
+
+	if (rtnl_handler_register(h->rtnl_handle, &h->ifadd_handler) < 0)
+		goto err_close;
+
+	if (rtnl_handler_register(h->rtnl_handle, &h->ifdel_handler) < 0)
+		goto err_unregister;
+
+	return h;
+
+err_unregister:
+	rtnl_handler_unregister(h->rtnl_handle, &h->ifadd_handler);
+err_close:
+	rtnl_close(h->rtnl_handle);
+	free(h);
+err:
+	return NULL;
+}
+
+/** Destructor of interface table
+ *
+ * \param nlif_handle A pointer to a ::nlif_handle created 
+ * via nlif_open()
+ */
+void nlif_close(struct nlif_handle *h)
+{
+	int i;
+	struct ifindex_node *this, *tmp;
+
+	assert(h != NULL);
+
+	rtnl_handler_unregister(h->rtnl_handle, &h->ifadd_handler);
+	rtnl_handler_unregister(h->rtnl_handle, &h->ifdel_handler);
+	rtnl_close(h->rtnl_handle);
+
+	for (i=0; i<16; i++) {
+		list_for_each_entry_safe(this, tmp, &h->ifindex_hash[i], head) {
+			list_del(&this->head);
+			free(this);
+		}
+	}
+
+	free(h);
+	h = NULL; /* bugtrap */
+}
+
+/** Receive message from netlink and update interface table
+ *
+ * \param nlif_handle A pointer to a ::nlif_handle created
+ * \return 0 if OK
+ */
+int nlif_catch(struct nlif_handle *h)
+{
+	assert(h != NULL);
+
+	if (h->rtnl_handle)
+		return rtnl_receive(h->rtnl_handle);
+
+	return -1;
+}
+
+static int nlif_catch_multi(struct nlif_handle *h)
+{
+	assert(h != NULL);
+
+	if (h->rtnl_handle)
+		return rtnl_receive_multi(h->rtnl_handle);
+
+	return -1;
+}
+
+/** 
+ * nlif_query - request a dump of interfaces available in the system
+ * @h: pointer to a valid nlif_handler
+ */
+int nlif_query(struct nlif_handle *h)
+{
+	assert(h != NULL);
+
+	if (rtnl_dump_type(h->rtnl_handle, RTM_GETLINK) < 0)
+		return -1;
+
+	return nlif_catch_multi(h);
+}
+
+/** Returns socket descriptor for the netlink socket
+ *
+ * \param nlif_handle A pointer to a ::nlif_handle created
+ * \return The fd or -1 if there's an error
+ */
+int nlif_fd(struct nlif_handle *h)
+{
+	assert(h != NULL);
+
+	if (h->rtnl_handle)
+		return h->rtnl_handle->rtnl_fd;
+
+	return -1;
+}