conntrack: add -C command to display the counter

This patch adds the -C command, to display the table counter. In the
case of `-C conntrack' the tool reads the proc interface. For
expectation, it loops on the table to count the number of entries
(as there is not proc interface to display the number of
expectations).

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

3 files changed, 55 insertions, 6 deletions

diff --git a/conntrack.8 b/conntrack.8
index 146e2df..94f4e41 100644
--- a/conntrack.8
+++ b/conntrack.8
@@ -72,6 +72,9 @@ Display a real-time event log.
 .TP
 .BI "-F, --flush "
 Flush the whole given table
+.TP
+.BI "-C, --count "
+Show the table counter.
 .SS PARAMETERS
 .TP
 .BI "-z, --zero "
diff --git a/include/conntrack.h b/include/conntrack.h
index 4787809..87a262d 100644
--- a/include/conntrack.h
+++ b/include/conntrack.h
@@ -59,8 +59,14 @@ enum action {
 
 	EXP_EVENT_BIT	= 14,
 	EXP_EVENT	= (1 << EXP_EVENT_BIT),
+
+	CT_COUNT_BIT	= 15,
+	CT_COUNT	= (1 << CT_COUNT_BIT),
+
+	EXP_COUNT_BIT	= 16,
+	EXP_COUNT	= (1 << EXP_COUNT_BIT),
 };
-#define NUMBER_OF_CMD   15
+#define NUMBER_OF_CMD   17
 
 enum options {
 	CT_OPT_ORIG_SRC_BIT	= 0,
diff --git a/src/conntrack.c b/src/conntrack.c
index e8b2c4f..6064fb7 100644
--- a/src/conntrack.c
+++ b/src/conntrack.c
@@ -54,13 +54,15 @@
 #include <signal.h>
 #include <string.h>
 #include <netdb.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <libnetfilter_conntrack/libnetfilter_conntrack.h>
 
 static const char cmdflags[NUMBER_OF_CMD]
-= {'L','I','U','D','G','F','E','V','h','L','I','D','G','F','E'};
+= {'L','I','U','D','G','F','E','V','h','L','I','D','G','F','E','C','C'};
 
 static const char cmd_need_param[NUMBER_OF_CMD]
-= { 2,  0,  0,  0,  0,  2,  2,  2,  2,  2,  0,  0,  0,  2,  2 };
+= { 2,  0,  0,  0,  0,  2,  2,  2,  2,  2,  0,  0,  0,  2,  2,  2,  2};
 
 static const char *optflags[NUMBER_OF_OPT] = {
 "src","dst","reply-src","reply-dst","protonum","timeout","status","zero",
@@ -138,6 +140,7 @@ static char commands_v_options[NUMBER_OF_CMD][NUMBER_OF_OPT] =
 /*EXP_GET*/   {1,1,2,2,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
 /*EXP_FLUSH*/ {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
 /*EXP_EVENT*/ {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+/*CT_COUNT*/  {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
 };
 
 static LIST_HEAD(proto_list);
@@ -858,6 +861,14 @@ static int dump_exp_cb(enum nf_conntrack_msg_type type,
 	return NFCT_CB_CONTINUE;
 }
 
+static int count_exp_cb(enum nf_conntrack_msg_type type,
+			struct nf_expect *exp,
+			void *data)
+{
+	counter++;
+	return NFCT_CB_CONTINUE;
+}
+
 static struct ctproto_handler *h;
 
 static const int cmd2type[][2] = {
@@ -869,6 +880,7 @@ static const int cmd2type[][2] = {
 	['E']	= { CT_EVENT,	EXP_EVENT },
 	['V']	= { CT_VERSION,	CT_VERSION },
 	['h']	= { CT_HELP,	CT_HELP },
+	['C']	= { CT_COUNT,	EXP_COUNT },
 };
 
 static const int opt2type[] = {
@@ -908,7 +920,7 @@ static const int opt2attr[] = {
 	['i']	= ATTR_ID,
 };
 
-static char exit_msg[][64] = {
+static char exit_msg[NUMBER_OF_CMD][64] = {
 	[CT_LIST_BIT] 		= "%d flow entries has been shown.\n",
 	[CT_CREATE_BIT]		= "%d flow entries has been created.\n",
 	[CT_UPDATE_BIT]		= "%d flow entries has been updated.\n",
@@ -955,7 +967,7 @@ int main(int argc, char *argv[])
 
 	while ((c = getopt_long(argc, argv, "L::I::U::D::G::E::F::hVs:d:r:q:"
 					    "p:t:u:e:a:z[:]:{:}:m:i:f:o:n::"
-					    "g::c:b:", 
+					    "g::c:b:C::", 
 					    opts, NULL)) != -1) {
 	switch(c) {
 		/* commands */
@@ -967,6 +979,7 @@ int main(int argc, char *argv[])
 		case 'E':
 		case 'V':
 		case 'h':
+		case 'C':
 			type = check_type(argc, argv);
 			add_command(&command, cmd2type[c][type]);
 			break;
@@ -1322,7 +1335,34 @@ int main(int argc, char *argv[])
 		res = nfexp_catch(cth);
 		nfct_close(cth);
 		break;
-			
+	case CT_COUNT: {
+#define NF_CONNTRACK_COUNT_PROC "/proc/sys/net/netfilter/nf_conntrack_count"
+		int fd, count;
+		char buf[strlen("2147483647")];	/* INT_MAX */
+		fd = open(NF_CONNTRACK_COUNT_PROC, O_RDONLY);
+		if (fd == -1) {
+			exit_error(OTHER_PROBLEM, "Can't open %s",
+				   NF_CONNTRACK_COUNT_PROC);
+		}
+		if (read(fd, buf, sizeof(buf)) == -1) {
+			exit_error(OTHER_PROBLEM, "Can't read %s",
+				   NF_CONNTRACK_COUNT_PROC);
+		}
+		close(fd);
+		count = atoi(buf);
+		printf("%d\n", count);
+		break;
+	}
+	case EXP_COUNT:
+		cth = nfct_open(EXPECT, 0);
+		if (!cth)
+			exit_error(OTHER_PROBLEM, "Can't open handler");
+
+		nfexp_callback_register(cth, NFCT_T_ALL, count_exp_cb, NULL);
+		res = nfexp_query(cth, NFCT_Q_DUMP, &family);
+		nfct_close(cth);
+		printf("%d\n", counter);
+		break;
 	case CT_VERSION:
 		printf("%s v%s (conntrack-tools)\n", PROGNAME, VERSION);
 		break;