From: Michal Sojka <sojkam1@fel.cvut.cz>
Date: Tue, 14 Jan 2014 10:17:01 +0000 (+0100)
Subject: ugw: Add nonblocking mode
X-Git-Tag: fix-allnoconfig~81
X-Git-Url: http://rtime.felk.cvut.cz/gitweb/can-benchmark.git/commitdiff_plain/05644389a630a808331c9c57d61ce02230bb235b

ugw: Add nonblocking mode
---

diff --git a/ugw/ugw.c b/ugw/ugw.c
index 482f4e1..0e653d3 100644
--- a/ugw/ugw.c
+++ b/ugw/ugw.c
@@ -20,6 +20,8 @@
 #include <poll.h>
 #include <sys/mman.h>
 #include <arpa/inet.h>
+#include <fcntl.h>
+#include <errno.h>
 
 #ifndef SO_BUSY_POLL
 #define SO_BUSY_POLL 46
@@ -41,10 +43,12 @@ enum { IN_READ, IN_RECVMMSG, IN_MMAP, IN_MMAPBUSY } in_method = IN_READ;
 enum { WRITE, OUT_MMAP } out_method = WRITE;
 bool quiet = false;
 int busy_poll_us = 0;
+bool nonblocking = false;
 
 enum in2out {
 	STORE_ONLY,
 	SEND,
+	NOP,
 };
 
 
@@ -70,6 +74,8 @@ struct out_ctx {
 enum in2out in_read(struct in_ctx *ctx, struct can_frame *cf)
 {
 	int ret = read(ctx->s, cf, sizeof(*cf));
+	if (nonblocking && ret == -1 && errno == EAGAIN)
+		return NOP;
 	if (ret != sizeof(*cf)) {
 		perror("read");
 		exit(1);
@@ -85,6 +91,11 @@ void init_read(struct in_ctx *ctx)
 
 	s = CHECK(socket(PF_CAN, SOCK_RAW, CAN_RAW));
 
+	if (nonblocking) {
+		int flags = CHECK(fcntl(s, F_GETFL, 0));
+		CHECK(fcntl(s, F_SETFL, flags | O_NONBLOCK));
+	}
+
 	if (busy_poll_us) {
 		CHECK(setsockopt(s, SOL_SOCKET, SO_BUSY_POLL,
 				 &busy_poll_us, sizeof(busy_poll_us)));
@@ -173,6 +184,9 @@ void init_packet_rx(struct in_ctx *ctx)
 
 int out_write(struct out_ctx *ctx, struct can_frame *cf)
 {
+	if (ctx->from_in == NOP)
+		return 0;
+
 	int ret = write(ctx->s, cf, sizeof(*cf));
 	if (ret != sizeof(*cf)) {
 		perror("write");
@@ -209,6 +223,10 @@ int out_packet_tx(struct out_ctx *ctx, struct can_frame *cf)
 	volatile struct tpacket2_hdr *hdr = ctx->ptr + ctx->current*FRAME_SIZE;
 	int ret = -1;
 
+	if (ctx->from_in == NOP)
+		return 0;
+
+
 	while (hdr->tp_status != TP_STATUS_AVAILABLE) {
 		struct pollfd pfd = {.fd = ctx->s, .revents = 0,
 				     .events = POLLIN|POLLRDNORM|POLLERR };
@@ -319,6 +337,11 @@ void gw()
 
 	while (1) {
 		oc.from_in = in(&ic, &cf);
+		switch (oc.from_in) {
+		case SEND:       stats.send++;  break;
+		case STORE_ONLY: stats.store++; break;
+		case NOP:	 		break;
+		}
 		out(&oc, &cf);
 	}
 }
@@ -328,11 +351,14 @@ int main(int argc, char *argv[])
 {
 	int opt;
 
-	while ((opt = getopt(argc, argv, "b:qr:t:")) != -1) {
+	while ((opt = getopt(argc, argv, "b:nqr:t:")) != -1) {
 		switch (opt) {
 		case 'b':
 			busy_poll_us = atoi(optarg);
 			break;
+		case 'n':
+			nonblocking = true;
+			break;
 		case 'q':
 			quiet = true;
 			break;