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

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;
+}