[bpf-next PATCH v2 2/7] bpf: add sendmsg option for testing BPF programs

[John Fastabend <john.fastabend@gmail.com>]

When testing BPF programs using sockmap I often want to have more
control over how sendmsg is exercised. This becomes even more useful
as new sockmap program types are added.

This adds a test type option to select type of test to run. Currently,
only "ping" and "sendmsg" are supported, but more can be added as
needed.

The new help argument gives the following,

 Usage: ./sockmap --cgroup <cgroup_path>
 options:
 --help         -h
 --cgroup       -c
 --rate         -r
 --verbose      -v
 --iov_count    -i
 --length       -l
 --test         -t

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
---
 samples/sockmap/sockmap_user.c |  143 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 140 insertions(+), 3 deletions(-)

diff --git a/samples/sockmap/sockmap_user.c b/samples/sockmap/sockmap_user.c
index 5cbe7a5..2d51672 100644
--- a/samples/sockmap/sockmap_user.c
+++ b/samples/sockmap/sockmap_user.c
@@ -56,6 +56,9 @@
 	{"cgroup",	required_argument,	NULL, 'c' },
 	{"rate",	required_argument,	NULL, 'r' },
 	{"verbose",	no_argument,		NULL, 'v' },
+	{"iov_count",	required_argument,	NULL, 'i' },
+	{"length",	required_argument,	NULL, 'l' },
+	{"test",	required_argument,	NULL, 't' },
 	{0, 0, NULL, 0 }
 };
 
@@ -184,6 +187,113 @@ static int sockmap_init_sockets(void)
 	return err;
 }
 
+struct msg_stats {
+	size_t bytes_sent;
+	size_t bytes_recvd;
+};
+
+static int msg_loop(int fd, int iov_count, int iov_length, int cnt,
+		    struct msg_stats *s, bool tx)
+{
+	struct msghdr msg = {0};
+	struct iovec *iov;
+	int i, flags = 0;
+
+	iov = calloc(iov_count, sizeof(struct iovec));
+	if (!iov)
+		return -ENOMEM;
+
+	for (i = 0; i < iov_count; i++) {
+		char *d = calloc(iov_length, sizeof(char));
+
+		if (!d) {
+			fprintf(stderr, "iov_count %i/%i OOM\n", i, iov_count);
+			free(iov);
+			return -ENOMEM;
+		}
+		iov[i].iov_base = d;
+		iov[i].iov_len = iov_length;
+	}
+
+	msg.msg_iov = iov;
+	msg.msg_iovlen = iov_count;
+
+	if (tx) {
+		for (i = 0; i < cnt; i++) {
+			int sent = sendmsg(fd, &msg, flags);
+
+			if (sent < 0) {
+				perror("send loop error:");
+				return sent;
+			}
+			s->bytes_sent += sent;
+		}
+	} else {
+		int slct, recv, max_fd = fd;
+		struct timeval timeout;
+		float total_bytes;
+		fd_set w;
+
+		total_bytes = (float)iov_count * (float)iov_length * (float)cnt;
+		while (s->bytes_recvd < total_bytes) {
+			timeout.tv_sec = 1;
+			timeout.tv_usec = 0;
+
+			/* FD sets */
+			FD_ZERO(&w);
+			FD_SET(fd, &w);
+
+			slct = select(max_fd + 1, &w, NULL, NULL, &timeout);
+			if (slct == -1) {
+				perror("select()");
+				return slct;
+			} else if (!slct) {
+				fprintf(stderr, "unexpected timeout\n");
+				return slct;
+			}
+
+			recv = recvmsg(fd, &msg, flags);
+			if (recv < 0) {
+				if (errno != EWOULDBLOCK) {
+					perror("recv failed()\n");
+					return errno;
+				}
+			}
+
+			s->bytes_recvd += recv;
+		}
+	}
+
+	for (i = 0; i < iov_count; i++)
+		free(iov[i].iov_base);
+	free(iov);
+	return 0;
+}
+
+static int sendmsg_test(int iov_count, int iov_buf, int cnt, int verbose)
+{
+	struct msg_stats s = {0};
+	int err;
+
+	err = msg_loop(c1, iov_count, iov_buf, cnt, &s, true);
+	if (err) {
+		fprintf(stderr,
+			"msg_loop_tx: iov_count %i iov_buf %i cnt %i err %i\n",
+			iov_count, iov_buf, cnt, err);
+		return err;
+	}
+
+	msg_loop(p2, iov_count, iov_buf, cnt, &s, false);
+	if (err)
+		fprintf(stderr,
+			"msg_loop_rx: iov_count %i iov_buf %i cnt %i err %i\n",
+			iov_count, iov_buf, cnt, err);
+
+	fprintf(stdout, "sendmsg: TX_bytes %zu RX_bytes %zu\n",
+		s.bytes_sent, s.bytes_recvd);
+	return err;
+}
+
 static int forever_ping_pong(int rate, int verbose)
 {
 	struct timeval timeout;
@@ -259,13 +369,19 @@ static int forever_ping_pong(int rate, int verbose)
 	return 0;
 }
 
+enum {
+	PING_PONG,
+	SENDMSG,
+};
+
 int main(int argc, char **argv)
 {
-	int rate = 1, verbose = 0;
+	int iov_count = 1, length = 1024, rate = 1, verbose = 0;
 	int opt, longindex, err, cg_fd = 0;
+	int test = PING_PONG;
 	char filename[256];
 
-	while ((opt = getopt_long(argc, argv, "hvc:r:",
+	while ((opt = getopt_long(argc, argv, "hvc:r:i:l:t:",
 				  long_options, &longindex)) != -1) {
 		switch (opt) {
 		/* Cgroup configuration */
@@ -283,6 +399,22 @@ int main(int argc, char **argv)
 		case 'v':
 			verbose = 1;
 			break;
+		case 'i':
+			iov_count = atoi(optarg);
+			break;
+		case 'l':
+			length = atoi(optarg);
+			break;
+		case 't':
+			if (memcmp(optarg, "ping", 4) == 0) {
+				test = PING_PONG;
+			} else if (memcmp(optarg, "sendmsg", 7) == 0) {
+				test = SENDMSG;
+			} else {
+				usage(argv);
+				return -1;
+			}
+			break;
 		case 'h':
 		default:
 			usage(argv);
@@ -340,7 +472,12 @@ int main(int argc, char **argv)
 		goto out;
 	}
 
-	err = forever_ping_pong(rate, verbose);
+	if (test == PING_PONG)
+		err = forever_ping_pong(rate, verbose);
+	else if (test == SENDMSG)
+		err = sendmsg_test(iov_count, length, rate, verbose);
+	else
+		fprintf(stderr, "unknown test\n");
 out:
 	close(s1);
 	close(s2);