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>

diff --git a/include/Makefile.am b/include/Makefile.am
index f22561bb12b1bd8bae2376c8a02df5f51fa0c11c..465d8047ab83f4d213ad9d6b157782cfa848337a 100644 (file)
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -4,6 +4,7 @@ noinst_HEADERS =        cli.h           \
                        datatype.h      \
                        expression.h    \
                        gmputil.h       \
+                       iface.h         \
                        mnl.h           \
                        nftables.h      \
                        payload.h       \

diff --git a/include/iface.h b/include/iface.h
new file mode 100644 (file)
index 0000000..f41ee8b
--- /dev/null
+++ b/include/iface.h
@@ -0,0 +1,18 @@
+#ifndef _NFTABLES_IFACE_H_
+#define _NFTABLES_IFACE_H_
+
+#include <net/if.h>
+
+struct iface {
+       struct list_head        list;
+       char                    name[IFNAMSIZ];
+       uint32_t                ifindex;
+};
+
+unsigned int nft_if_nametoindex(const char *name);
+char *nft_if_indextoname(unsigned int ifindex, char *name);
+
+void iface_cache_update(void);
+void iface_cache_release(void);
+
+#endif

diff --git a/src/Makefile.am b/src/Makefile.am
index 2410fd371fecddfe7b4b35983e3d1031f435b4f3..fd6321937bdebe94222d44cf013cefa2acca805e 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -44,6 +44,7 @@ nft_SOURCES = main.c                          \
                utils.c                         \
                erec.c                          \
                mnl.c                           \
+               iface.c                         \
                scanner.l                       \
                parser_bison.y
 

diff --git a/src/cli.c b/src/cli.c
index f3827b8192bf386589b57a2494a54cb9b9a07f20..fbae0ef3efeb590ca71d866ee374571470b5494b 100644 (file)
--- a/src/cli.c
+++ b/src/cli.c
@@ -28,6 +28,7 @@
 #include <parser.h>
 #include <erec.h>
 #include <utils.h>
+#include <iface.h>
 #include <cli.h>
 
 #define CMDLINE_HISTFILE       ".nft.history"
@@ -123,6 +124,7 @@ static void cli_complete(char *line)
        nft_run(scanner, state, &msgs);
        erec_print_list(stdout, &msgs);
        xfree(line);
+       iface_cache_release();
 }
 
 static char **cli_completion(const char *text, int start, int end)

diff --git a/src/iface.c b/src/iface.c
new file mode 100644 (file)
index 0000000..9936388
--- /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;
+}

diff --git a/src/main.c b/src/main.c
index 4590c30b7844cb5384abf8f9cfeb68413e6ed0e9..bfe589a03b1ed1b53c05f05c4484397b1f7cada3 100644 (file)
--- a/src/main.c
+++ b/src/main.c
@@ -25,6 +25,7 @@
 #include <netlink.h>
 #include <erec.h>
 #include <mnl.h>
+#include <iface.h>
 #include <cli.h>
 
 unsigned int max_errors = 10;
@@ -362,7 +363,8 @@ int main(int argc, char * const *argv)
 out:
        scanner_destroy(scanner);
        erec_print_list(stderr, &msgs);
-
        xfree(buf);
+       iface_cache_release();
+
        return rc;
 }

diff --git a/src/meta.c b/src/meta.c
index ad57228a8131ec5e127b26a92e7d64468c4ff53a..bfc12580d4afe80975ffbb76ba7e3719156c1704 100644 (file)
--- a/src/meta.c
+++ b/src/meta.c
@@ -30,6 +30,7 @@
 #include <gmputil.h>
 #include <utils.h>
 #include <erec.h>
+#include <iface.h>
 
 static struct symbol_table *realm_tbl;
 static void __init realm_table_init(void)
@@ -138,7 +139,7 @@ static void ifindex_type_print(const struct expr *expr)
        int ifindex;
 
        ifindex = mpz_get_uint32(expr->value);
-       if (if_indextoname(ifindex, name))
+       if (nft_if_indextoname(ifindex, name))
                printf("%s", name);
        else
                printf("%d", ifindex);
@@ -149,7 +150,7 @@ static struct error_record *ifindex_type_parse(const struct expr *sym,
 {
        int ifindex;
 
-       ifindex = if_nametoindex(sym->identifier);
+       ifindex = nft_if_nametoindex(sym->identifier);
        if (ifindex == 0)
                return error(&sym->location, "Interface does not exist");