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authorPablo Neira Ayuso <pablo@netfilter.org>2015-04-09 14:15:15 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2015-04-11 19:22:45 +0200
commit3ed296118a065caff5600e60d4f7ef18e137f9a0 (patch)
tree50e6776142bf52a6a3b1ae5ae65631c1d1faa9ca /src/iface.c
parent628122466c32e7f1795c9754a46e6b6b91e71aa5 (diff)
src: restore interface to index cache
nftables used to have a cache to speed up interface name <-> index lookup, restore it using libmnl. This reduces netlink traffic since if_nametoindex() and if_indextoname() open, send a request, receive the list of interface and close a netlink socket for each call. I think this is also good for consistency since nft -f will operate with the same index number when reloading the ruleset. The cache is populated by when nft_if_nametoindex() and nft_if_indextoname() are used for first time. Then, it it released in the output path. In the interactive mode, it is invalidated after each command. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src/iface.c')
-rw-r--r--src/iface.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/src/iface.c b/src/iface.c
new file mode 100644
index 00000000..9936388b
--- /dev/null
+++ b/src/iface.c
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <net/if.h>
+#include <time.h>
+#include <string.h>
+#include <errno.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/rtnetlink.h>
+
+#include <nftables.h>
+#include <list.h>
+#include <netlink.h>
+#include <iface.h>
+
+static LIST_HEAD(iface_list);
+static bool iface_cache_init;
+
+static int data_attr_cb(const struct nlattr *attr, void *data)
+{
+ const struct nlattr **tb = data;
+ int type = mnl_attr_get_type(attr);
+
+ if (mnl_attr_type_valid(attr, IFLA_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case IFLA_IFNAME:
+ if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
+ netlink_abi_error();
+ break;
+ default:
+ return MNL_CB_OK;
+ }
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static int data_cb(const struct nlmsghdr *nlh, void *data)
+{
+ struct nlattr *tb[IFLA_MAX + 1] = {};
+ struct ifinfomsg *ifm = mnl_nlmsg_get_payload(nlh);
+ struct iface *iface;
+
+ iface = xmalloc(sizeof(struct iface));
+ iface->ifindex = ifm->ifi_index;
+ mnl_attr_parse(nlh, sizeof(*ifm), data_attr_cb, tb);
+ strncpy(iface->name, mnl_attr_get_str(tb[IFLA_IFNAME]), IFNAMSIZ);
+ list_add(&iface->list, &iface_list);
+
+ return MNL_CB_OK;
+}
+
+void iface_cache_update(void)
+{
+ char buf[MNL_SOCKET_BUFFER_SIZE];
+ struct mnl_socket *nl;
+ struct nlmsghdr *nlh;
+ struct rtgenmsg *rt;
+ uint32_t seq, portid;
+ int ret;
+
+ nlh = mnl_nlmsg_put_header(buf);
+ nlh->nlmsg_type = RTM_GETLINK;
+ nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
+ nlh->nlmsg_seq = seq = time(NULL);
+ rt = mnl_nlmsg_put_extra_header(nlh, sizeof(struct rtgenmsg));
+ rt->rtgen_family = AF_PACKET;
+
+ nl = mnl_socket_open(NETLINK_ROUTE);
+ if (nl == NULL)
+ netlink_init_error();
+
+ if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0)
+ netlink_init_error();
+
+ portid = mnl_socket_get_portid(nl);
+
+ if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0)
+ netlink_init_error();
+
+ ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+ while (ret > 0) {
+ ret = mnl_cb_run(buf, ret, seq, portid, data_cb, NULL);
+ if (ret <= MNL_CB_STOP)
+ break;
+ ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+ }
+ if (ret == -1)
+ netlink_init_error();
+
+ mnl_socket_close(nl);
+
+ iface_cache_init = true;
+}
+
+void iface_cache_release(void)
+{
+ struct iface *iface, *next;
+
+ if (!iface_cache_init)
+ return;
+
+ list_for_each_entry_safe(iface, next, &iface_list, list) {
+ list_del(&iface->list);
+ free(iface);
+ }
+ iface_cache_init = false;
+}
+
+unsigned int nft_if_nametoindex(const char *name)
+{
+ struct iface *iface;
+
+ if (!iface_cache_init)
+ iface_cache_update();
+
+ list_for_each_entry(iface, &iface_list, list) {
+ if (strncmp(name, iface->name, IFNAMSIZ) == 0)
+ return iface->ifindex;
+ }
+ return 0;
+}
+
+char *nft_if_indextoname(unsigned int ifindex, char *name)
+{
+ struct iface *iface;
+
+ if (!iface_cache_init)
+ iface_cache_update();
+
+ list_for_each_entry(iface, &iface_list, list) {
+ if (iface->ifindex == ifindex) {
+ strncpy(name, iface->name, IFNAMSIZ);
+ return name;
+ }
+ }
+ return NULL;
+}