netsniff-ng: v3: fix packet accounting on --num

We need to carry frame_count through multiple calls of walk function
to account correctly for --num <pkts>. Also, move socket stats printing
into rx ring, since it belongs there.

Todo: the kernel socket seems to have a different count that what we
see. This needs to be fixed one way or the other. Not yet sure what's
causing this.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

5 files changed, 34 insertions, 30 deletions

diff --git a/netsniff-ng.c b/netsniff-ng.c
index 899a148..b61dec9 100644
--- a/netsniff-ng.c
+++ b/netsniff-ng.c
@@ -476,7 +476,7 @@ static void receive_to_xmit(struct ctx *ctx)
 
 	timer_purge();
 
-	sock_print_net_stats(rx_sock);
+	sock_rx_net_stats(rx_sock);
 
 	bpf_release(&bpf_ops);
 
@@ -809,11 +809,10 @@ static void print_pcap_file_stats(int sock, struct ctx *ctx)
 }
 
 static void walk_t3_block(struct block_desc *pbd, struct ctx *ctx,
-			  int sock, int fd)
+			  int sock, int fd, unsigned long *frame_count)
 {
 	uint8_t *packet;
 	int num_pkts = pbd->h1.num_pkts, i, ret;
-	unsigned long frame_count = 0;
 	struct tpacket3_hdr *hdr;
 	pcap_pkthdr_t phdr;
 	struct sockaddr_ll *sll;
@@ -824,12 +823,13 @@ static void walk_t3_block(struct block_desc *pbd, struct ctx *ctx,
 	for (i = 0; i < num_pkts && likely(sigint == 0); ++i) {
 		__label__ next;
 		packet = ((uint8_t *) hdr + hdr->tp_mac);
-		frame_count++;
 
 		if (ctx->packet_type != -1)
 			if (ctx->packet_type != sll->sll_pkttype)
 				goto next;
 
+		(*frame_count)++;
+
 		if (dump_to_pcap(ctx)) {
 			tpacket3_hdr_to_pcap_pkthdr(hdr, sll, &phdr, ctx->magic);
 
@@ -849,7 +849,7 @@ static void walk_t3_block(struct block_desc *pbd, struct ctx *ctx,
 		sll = (void *) ((uint8_t *) hdr + TPACKET_ALIGN(sizeof(*hdr)));
 
 		if (frame_count_max != 0) {
-			if (frame_count >= frame_count_max) {
+			if (unlikely(*frame_count >= frame_count_max)) {
 				sigint = 1;
 				break;
 			}
@@ -885,6 +885,7 @@ static void recv_only_or_dump(struct ctx *ctx)
 	struct sock_fprog bpf_ops;
 	struct timeval start, end, diff;
 	struct block_desc *pbd;
+	unsigned long frame_count = 0;
 
 	sock = pf_socket();
 
@@ -967,7 +968,7 @@ static void recv_only_or_dump(struct ctx *ctx)
 	while (likely(sigint == 0)) {
 		while (user_may_pull_from_rx_block((pbd = (void *)
 				rx_ring.frames[it].iov_base))) {
-			walk_t3_block(pbd, ctx, sock, fd);
+			walk_t3_block(pbd, ctx, sock, fd, &frame_count);
 
 			kernel_may_pull_from_rx_block(pbd);
 			it = (it + 1) % rx_ring.layout3.tp_block_nr;
@@ -983,7 +984,7 @@ static void recv_only_or_dump(struct ctx *ctx)
 	timersub(&end, &start, &diff);
 
 	if (!(ctx->dump_dir && ctx->print_mode == PRINT_NONE)) {
-		sock_print_net_stats(sock);
+		sock_rx_net_stats(sock);
 
 		printf("\r%12lu  sec, %lu usec in total\n",
 		       diff.tv_sec, diff.tv_usec);
diff --git a/ring_rx.c b/ring_rx.c
index 28ecaf4..c674332 100644
--- a/ring_rx.c
+++ b/ring_rx.c
@@ -130,3 +130,28 @@ void bind_rx_ring(int sock, struct ring *ring, int ifindex)
 {
 	bind_ring_generic(sock, ring, ifindex);
 }
+
+void sock_rx_net_stats(int sock)
+{
+	int ret;
+	bool v3 = get_sockopt_tpacket(sock) == TPACKET_V3;
+	union {
+		struct tpacket_stats	k2;
+		struct tpacket_stats_v3 k3;
+	} stats;
+	socklen_t slen = v3 ? sizeof(stats.k3) : sizeof(stats.k2);
+
+	memset(&stats, 0, sizeof(stats));
+	ret = getsockopt(sock, SOL_PACKET, PACKET_STATISTICS, &stats, &slen);
+	if (ret > -1) {
+		uint64_t packets = stats.k3.tp_packets;
+		uint64_t drops = stats.k3.tp_drops;
+
+		printf("\r%12ld  packets incoming\n", packets);
+		printf("\r%12ld  packets passed filter\n", packets - drops);
+		printf("\r%12ld  packets failed filter (out of space)\n", drops);
+		if (stats.k3.tp_packets > 0)
+			printf("\r%12.4lf%\% packet droprate\n",
+			       (1.0 * drops / packets) * 100.0);
+	}
+}
diff --git a/ring_rx.h b/ring_rx.h
index 9c72cda..43b4020 100644
--- a/ring_rx.h
+++ b/ring_rx.h
@@ -17,6 +17,7 @@ extern void alloc_rx_ring_frames(int sock, struct ring *ring);
 extern void bind_rx_ring(int sock, struct ring *ring, int ifindex);
 extern void setup_rx_ring_layout(int sock, struct ring *ring,
 				 unsigned int size, bool jumbo_support, bool v3);
+extern void sock_rx_net_stats(int sock);
 
 static inline int user_may_pull_from_rx(struct tpacket2_hdr *hdr)
 {
diff --git a/xutils.c b/xutils.c
index a5fbb3c..eea258c 100644
--- a/xutils.c
+++ b/xutils.c
@@ -608,28 +608,6 @@ void device_set_flags(const char *ifname, const short flags)
 	close(sock);
 }
 
-void sock_print_net_stats(int sock)
-{
-	int ret;
-	struct tpacket_stats kstats;
-
-	socklen_t slen = sizeof(kstats);
-
-	memset(&kstats, 0, sizeof(kstats));
-	ret = getsockopt(sock, SOL_PACKET, PACKET_STATISTICS, &kstats, &slen);
-	if (ret > -1) {
-		uint64_t packets = kstats.tp_packets;
-		uint64_t drops = kstats.tp_drops;
-
-		printf("\r%12ld  packets incoming\n", packets);
-		printf("\r%12ld  packets passed filter\n", packets - drops);
-		printf("\r%12ld  packets failed filter (out of space)\n", drops);
-		if (kstats.tp_packets > 0)
-			printf("\r%12.4lf%\% packet droprate\n",
-			       (1.0 * drops / packets) * 100.0);
-	}
-}
-
 void register_signal(int signal, void (*handler)(int))
 {
 	sigset_t block_mask;
diff --git a/xutils.h b/xutils.h
index 28a307b..ce8ee75 100644
--- a/xutils.h
+++ b/xutils.h
@@ -36,7 +36,6 @@ extern int ethtool_drvinf(const char *ifname, struct ethtool_drvinfo *drvinf);
 extern int ethtool_link(const char *ifname);
 extern int device_mtu(const char *ifname);
 extern int device_address(const char *ifname, int af, struct sockaddr_storage *ss);
-extern void sock_print_net_stats(int sock);
 extern int device_ifindex(const char *ifname);
 extern short device_get_flags(const char *ifname);
 extern void device_set_flags(const char *ifname, const short flags);