sock: Add spdk_sock_readv(sock, iov, iovcnt)

Add an new API spdk_sock_readv(sock, iov, iovcnt) to the sock
library. This will be used in SPDK iSCSI target first.

Implementation was done based on vcom_socket_readv in VPP.

Change-Id: I88a8f2af4856b1035165b78d76b4a4f4587b265d
Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/446343
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

include/spdk/sock.h

@@ -126,6 +126,17 @@ ssize_t spdk_sock_recv(struct spdk_sock *sock, void *buf, size_t len);
  */
 ssize_t spdk_sock_writev(struct spdk_sock *sock, struct iovec *iov, int iovcnt);
 
+/**
+ * Read message from the given socket to the I/O vector array.
+ *
+ * \param sock Socket to receive message.
+ * \param iov I/O vector.
+ * \param iovcnt Number of I/O vectors in the array.
+ *
+ * \return the length of the received message on success, -1 on failure.
+ */
+ssize_t spdk_sock_readv(struct spdk_sock *sock, struct iovec *iov, int iovcnt);
+
 /**
  * Set the value used to specify the low water mark (in bytes) for this socket.
  *

include/spdk_internal/sock.h

@@ -75,6 +75,7 @@ struct spdk_net_impl {
 	struct spdk_sock *(*accept)(struct spdk_sock *sock);
 	int (*close)(struct spdk_sock *sock);
 	ssize_t (*recv)(struct spdk_sock *sock, void *buf, size_t len);
+	ssize_t (*readv)(struct spdk_sock *sock, struct iovec *iov, int iovcnt);
 	ssize_t (*writev)(struct spdk_sock *sock, struct iovec *iov, int iovcnt);
 
 	int (*set_recvlowat)(struct spdk_sock *sock, int nbytes);

lib/sock/posix/posix.c

@@ -372,6 +372,14 @@ spdk_posix_sock_recv(struct spdk_sock *_sock, void *buf, size_t len)
 	return recv(sock->fd, buf, len, MSG_DONTWAIT);
 }
 
+static ssize_t
+spdk_posix_sock_readv(struct spdk_sock *_sock, struct iovec *iov, int iovcnt)
+{
+	struct spdk_posix_sock *sock = __posix_sock(_sock);
+
+	return readv(sock->fd, iov, iovcnt);
+}
+
 static ssize_t
 spdk_posix_sock_writev(struct spdk_sock *_sock, struct iovec *iov, int iovcnt)
 {
@@ -588,6 +596,7 @@ static struct spdk_net_impl g_posix_net_impl = {
 	.accept		= spdk_posix_sock_accept,
 	.close		= spdk_posix_sock_close,
 	.recv		= spdk_posix_sock_recv,
+	.readv		= spdk_posix_sock_readv,
 	.writev		= spdk_posix_sock_writev,
 	.set_recvlowat	= spdk_posix_sock_set_recvlowat,
 	.set_recvbuf	= spdk_posix_sock_set_recvbuf,

lib/sock/sock.c

@@ -129,6 +129,17 @@ spdk_sock_recv(struct spdk_sock *sock, void *buf, size_t len)
 	return sock->net_impl->recv(sock, buf, len);
 }
 
+ssize_t
+spdk_sock_readv(struct spdk_sock *sock, struct iovec *iov, int iovcnt)
+{
+	if (sock == NULL) {
+		errno = EBADF;
+		return -1;
+	}
+
+	return sock->net_impl->readv(sock, iov, iovcnt);
+}
+
 ssize_t
 spdk_sock_writev(struct spdk_sock *sock, struct iovec *iov, int iovcnt)
 {
@@ -140,7 +151,6 @@ spdk_sock_writev(struct spdk_sock *sock, struct iovec *iov, int iovcnt)
 	return sock->net_impl->writev(sock, iov, iovcnt);
 }
 
-
 int
 spdk_sock_set_recvlowat(struct spdk_sock *sock, int nbytes)
 {

lib/sock/vpp/vpp.c

@@ -385,6 +385,36 @@ spdk_vpp_sock_recv(struct spdk_sock *_sock, void *buf, size_t len)
 	return rc;
 }
 
+static ssize_t
+spdk_vpp_sock_readv(struct spdk_sock *_sock, struct iovec *iov, int iovcnt)
+{
+	struct spdk_vpp_sock *sock = __vpp_sock(_sock);
+	ssize_t total = 0;
+	int i, rc;
+
+	assert(sock != NULL);
+	assert(g_vpp_initialized);
+
+	for (i = 0; i < iovcnt; ++i) {
+		rc = vppcom_session_read(sock->fd, iov[i].iov_base, iov[i].iov_len);
+		if (rc < 0) {
+			if (total > 0) {
+				break;
+			} else {
+				errno = -rc;
+				return -1;
+			}
+		} else {
+			total += rc;
+			if (rc < iov[i].iov_len) {
+				/* Read less than buffer provided, no point to continue. */
+				break;
+			}
+		}
+	}
+	return total;
+}
+
 static ssize_t
 spdk_vpp_sock_writev(struct spdk_sock *_sock, struct iovec *iov, int iovcnt)
 {
@@ -411,7 +441,6 @@ spdk_vpp_sock_writev(struct spdk_sock *_sock, struct iovec *iov, int iovcnt)
 	return total;
 }
 
-
 /*
  * TODO: Check if there are similar parameters to configure in VPP
  * to three below.
@@ -609,6 +638,7 @@ static struct spdk_net_impl g_vpp_net_impl = {
 	.accept		= spdk_vpp_sock_accept,
 	.close		= spdk_vpp_sock_close,
 	.recv		= spdk_vpp_sock_recv,
+	.readv		= spdk_vpp_sock_readv,
 	.writev		= spdk_vpp_sock_writev,
 	.set_recvlowat	= spdk_vpp_sock_set_recvlowat,
 	.set_recvbuf	= spdk_vpp_sock_set_recvbuf,

test/unit/lib/sock/sock.c/sock_ut.c

@@ -171,6 +171,31 @@ spdk_ut_sock_recv(struct spdk_sock *_sock, void *buf, size_t len)
 	return len;
 }
 
+static ssize_t
+spdk_ut_sock_readv(struct spdk_sock *_sock, struct iovec *iov, int iovcnt)
+{
+	struct spdk_ut_sock *sock = __ut_sock(_sock);
+	size_t len;
+	char tmp[256];
+
+	/* Test implementation only supports single iov for now. */
+	CU_ASSERT(iovcnt == 1);
+
+	len = spdk_min(iov[0].iov_len, sock->bytes_avail);
+
+	if (len == 0) {
+		errno = EAGAIN;
+		return -1;
+	}
+
+	memcpy(iov[0].iov_base, sock->buf, len);
+	memcpy(tmp, &sock->buf[len], sock->bytes_avail - len);
+	memcpy(sock->buf, tmp, sock->bytes_avail - len);
+	sock->bytes_avail -= len;
+
+	return len;
+}
+
 static ssize_t
 spdk_ut_sock_writev(struct spdk_sock *_sock, struct iovec *iov, int iovcnt)
 {
@@ -285,6 +310,7 @@ static struct spdk_net_impl g_ut_net_impl = {
 	.accept		= spdk_ut_sock_accept,
 	.close		= spdk_ut_sock_close,
 	.recv		= spdk_ut_sock_recv,
+	.readv		= spdk_ut_sock_readv,
 	.writev		= spdk_ut_sock_writev,
 	.set_recvlowat	= spdk_ut_sock_set_recvlowat,
 	.set_recvbuf	= spdk_ut_sock_set_recvbuf,
@@ -331,6 +357,7 @@ _sock(const char *ip, int port)
 	server_sock = spdk_sock_accept(listen_sock);
 	SPDK_CU_ASSERT_FATAL(server_sock != NULL);
 
+	/* Test spdk_sock_recv */
 	iov.iov_base = test_string;
 	iov.iov_len = 7;
 	bytes_written = spdk_sock_writev(client_sock, &iov, 1);
@@ -348,6 +375,30 @@ _sock(const char *ip, int port)
 
 	CU_ASSERT(strncmp(test_string, buffer, 7) == 0);
 
+	/* Test spdk_sock_readv */
+	iov.iov_base = test_string;
+	iov.iov_len = 7;
+	bytes_written = spdk_sock_writev(client_sock, &iov, 1);
+	CU_ASSERT(bytes_written == 7);
+
+	usleep(1000);
+
+	iov.iov_base = buffer;
+	iov.iov_len = 2;
+	bytes_read = spdk_sock_readv(server_sock, &iov, 1);
+	CU_ASSERT(bytes_read == 2);
+
+	usleep(1000);
+
+	iov.iov_base = buffer + 2;
+	iov.iov_len = 5;
+	bytes_read += spdk_sock_readv(server_sock, &iov, 1);
+	CU_ASSERT(bytes_read == 7);
+
+	usleep(1000);
+
+	CU_ASSERT(strncmp(test_string, buffer, 7) == 0);
+
 	rc = spdk_sock_close(&client_sock);
 	CU_ASSERT(client_sock == NULL);
 	CU_ASSERT(rc == 0);