examples: add nft-compat-get

This utility allows to consult x_tables match/target revisions supported
via the nft_compat layer.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/examples/Makefile.am b/examples/Makefile.am
index 1c72ab47006187919013b4b8a2a5fe6260dbbe53..31e53bfea5d16289dfe074cbe53dd1bf1e25f8f3 100644 (file)
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -8,7 +8,8 @@ check_PROGRAMS = nft-table-add          \
                 nft-chain-get          \
                 nft-rule-add           \
                 nft-rule-del           \
-                nft-rule-get
+                nft-rule-get           \
+                nft-compat-get
 
 nft_table_add_SOURCES = nft-table-add.c
 nft_table_add_LDADD = ../src/libnftables.la ${LIBMNL_LIBS}
@@ -36,3 +37,6 @@ nft_rule_del_LDADD = ../src/libnftables.la ${LIBMNL_LIBS}
 
 nft_rule_get_SOURCES = nft-rule-get.c
 nft_rule_get_LDADD = ../src/libnftables.la ${LIBMNL_LIBS}
+
+nft_compat_get_SOURCES = nft-compat-get.c
+nft_compat_get_LDADD = ../src/libnftables.la ${LIBMNL_LIBS}

diff --git a/examples/nft-compat-get.c b/examples/nft-compat-get.c
new file mode 100644 (file)
index 0000000..3294028
--- /dev/null
+++ b/examples/nft-compat-get.c
@@ -0,0 +1,139 @@
+/*
+ * (C) 2012 by 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 as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
+ */
+
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+#include <netinet/in.h>
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nf_tables_compat.h>
+
+#include <libmnl/libmnl.h>
+
+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, NFTA_COMPAT_MAX) < 0)
+               return MNL_CB_OK;
+
+       switch(type) {
+       case NFTA_COMPAT_NAME:
+               if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
+                       perror("mnl_attr_validate");
+                       return MNL_CB_ERROR;
+               }
+               break;
+       case NFTA_COMPAT_REV:
+       case NFTA_COMPAT_TYPE:
+               if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+                       perror("mnl_attr_validate");
+                       return MNL_CB_ERROR;
+               }
+               break;
+       }
+       tb[type] = attr;
+       return MNL_CB_OK;
+}
+
+static int cb(const struct nlmsghdr *nlh, void *data)
+{
+       struct nlattr *tb[NFTA_COMPAT_MAX+1] = {};
+       struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
+
+       mnl_attr_parse(nlh, sizeof(*nfg), data_attr_cb, tb);
+
+       if (tb[NFTA_COMPAT_NAME])
+               printf("name=%s ", mnl_attr_get_str(tb[NFTA_COMPAT_NAME]));
+       if (tb[NFTA_COMPAT_REV])
+               printf("rev=%d ", ntohl(mnl_attr_get_u32(tb[NFTA_COMPAT_REV])));
+       if (tb[NFTA_COMPAT_TYPE])
+               printf("type=%d ", ntohl(mnl_attr_get_u32(tb[NFTA_COMPAT_REV])));
+
+       printf("\n");
+
+       return MNL_CB_OK;
+}
+
+int main(int argc, char *argv[])
+{
+       struct mnl_socket *nl;
+       char buf[MNL_SOCKET_BUFFER_SIZE];
+       struct nlmsghdr *nlh;
+       uint32_t portid, seq, rev, type;
+       int ret;
+
+       if (argc != 4) {
+               fprintf(stderr, "Usage: %s <extension_name> <type> <rev>\n",
+                       argv[0]);
+               return EXIT_FAILURE;
+       }
+
+       if (strcmp(argv[2], "target") == 0)
+               type = 1;
+       else if (strcmp(argv[2], "match") == 0)
+               type = 0;
+       else {
+               fprintf(stderr, "type should be `target' or `match'\n");
+               return EXIT_FAILURE;
+       }
+       rev = atoi(argv[3]);
+
+       nlh = mnl_nlmsg_put_header(buf);
+       nlh->nlmsg_type = (NFNL_SUBSYS_NFT_COMPAT << 8) | NFNL_MSG_COMPAT_GET;
+       nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+       nlh->nlmsg_seq = seq = time(NULL);
+
+       struct nfgenmsg *nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+       nfg->nfgen_family = AF_INET;
+       nfg->version = NFNETLINK_V0;
+       nfg->res_id = 0;
+
+       mnl_attr_put_strz(nlh, NFTA_COMPAT_NAME, argv[1]);
+       mnl_attr_put_u32(nlh, NFTA_COMPAT_REV, htonl(rev));
+       mnl_attr_put_u32(nlh, NFTA_COMPAT_TYPE, htonl(type));
+
+       printf("requesting `%s' rev=%d type=%d\n", argv[1], rev, type);
+
+       nl = mnl_socket_open(NETLINK_NETFILTER);
+       if (nl == NULL) {
+               perror("mnl_socket_open");
+               exit(EXIT_FAILURE);
+       }
+
+       if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
+               perror("mnl_socket_bind");
+               exit(EXIT_FAILURE);
+       }
+       portid = mnl_socket_get_portid(nl);
+
+       if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+               perror("mnl_socket_send");
+               exit(EXIT_FAILURE);
+       }
+
+       ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+       while (ret > 0) {
+               ret = mnl_cb_run(buf, ret, seq, portid, cb, NULL);
+               if (ret <= 0)
+                       break;
+               ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+       }
+       if (ret == -1) {
+               perror("error");
+               exit(EXIT_FAILURE);
+       }
+       mnl_socket_close(nl);
+
+       return EXIT_SUCCESS;
+}

diff --git a/include/linux/netfilter/nf_tables_compat.h b/include/linux/netfilter/nf_tables_compat.h
new file mode 100644 (file)
index 0000000..36fb81d
--- /dev/null
+++ b/include/linux/netfilter/nf_tables_compat.h
@@ -0,0 +1,20 @@
+#ifndef _NFT_COMPAT_NFNETLINK_H_
+#define _NFT_COMPAT_NFNETLINK_H_
+
+#define NFT_COMPAT_NAME_MAX    32
+
+enum {
+       NFNL_MSG_COMPAT_GET,
+       NFNL_MSG_COMPAT_MAX
+};
+
+enum {
+       NFTA_COMPAT_UNSPEC = 0,
+       NFTA_COMPAT_NAME,
+       NFTA_COMPAT_REV,
+       NFTA_COMPAT_TYPE,
+       __NFTA_COMPAT_MAX,
+};
+#define NFTA_COMPAT_MAX (__NFTA_COMPAT_MAX - 1)
+
+#endif

diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h
index 0d2e4fb2deb37f3369abd8e67e4ea8bd688ab24d..91eebab4918d44af18cc4f0cfa59a647dd80a89f 100644 (file)
--- a/include/linux/netfilter/nfnetlink.h
+++ b/include/linux/netfilter/nfnetlink.h
@@ -54,7 +54,8 @@ struct nfgenmsg {
 #define NFNL_SUBSYS_CTNETLINK_TIMEOUT  8
 #define NFNL_SUBSYS_CTHELPER           9
 #define NFNL_SUBSYS_NFTABLES           10
-#define NFNL_SUBSYS_COUNT              11
+#define NFNL_SUBSYS_NFT_COMPAT         11
+#define NFNL_SUBSYS_COUNT              12
 
 #ifdef __KERNEL__