3 files changed, 117 insertions, 2 deletions

diff --git a/src/libgsmd/lgsm_internals.h b/src/libgsmd/lgsm_internals.h
index 66fd5fe..0601959 100644
--- a/src/libgsmd/lgsm_internals.h
+++ b/src/libgsmd/lgsm_internals.h
@@ -1,4 +1,13 @@
+#ifndef _LGSM_INTERNALS_H
+#define _LGSM_INTERNALS_H
+
+#include <gsmd/usock.h>
+
+typedef int lgsm_msg_handler(struct lgsm_handle *lh, struct gsmd_msg_hdr *gmh);
 
 struct lgsm_handle {
 	int fd;
+	lgsm_msg_handler *handler[__NUM_GSMD_MSGS];
 };
+
+#endif /* _LGSM_INTERNALS_H */
diff --git a/src/libgsmd/libgsmd.c b/src/libgsmd/libgsmd.c
index 77b8499..104a8b3 100644
--- a/src/libgsmd/libgsmd.c
+++ b/src/libgsmd/libgsmd.c
@@ -36,7 +36,6 @@ static int lgsm_get_packet(struct lgsm_handle *lh)
 	return 0;
 }
 
-
 static int lgsm_open_backend(struct lgsm_handle *lh, const char *device)
 {
 	int rc;
@@ -52,7 +51,6 @@ static int lgsm_open_backend(struct lgsm_handle *lh, const char *device)
 		memset(&sun, 0, sizeof(sun));
 		sun.sun_family = AF_UNIX;
 		memcpy(sun.sun_path, GSMD_UNIX_SOCKET, sizeof(GSMD_UNIX_SOCKET));
-		printf("sizeof(GSMD_UNIX_SOCKET) = %u\n", sizeof(GSMD_UNIX_SOCKET));
 
 		rc = connect(lh->fd, (struct sockaddr *)&sun, sizeof(sun));
 		if (rc < 0) {
@@ -66,6 +64,49 @@ static int lgsm_open_backend(struct lgsm_handle *lh, const char *device)
 	return 0;
 }
 
+/* handle a packet that was received on the gsmd socket */
+int lgsm_handle_packet(struct lgsm_handle *lh, char *buf, int len)
+{
+	struct gsmd_msg_hdr *gmh = (struct gsmd_msg_hdr *)buf;
+	if (len < sizeof(*gmh))
+		return -EINVAL;
+	
+	if (len - sizeof(*gmh) < gmh->len)
+		return -EINVAL;
+	
+	if (gmh->msg_type >= __NUM_GSMD_MSGS)
+		return -EINVAL;
+	
+	return lh->handler[gmh->msg_type](lh, gmh);
+}
+
+/* blocking read and processing of packets until packet matching 'id' is found */
+int lgsm_blocking_wait_packet(struct lgsm_handle *lh, u_int16_t id, 
+			      struct gsmd_msg_hdr *gmh, int rlen)
+{
+	int rc;
+	fd_set readset;
+
+	FD_ZERO(&readset);
+
+	while (1) {
+		FD_SET(lh->fd, &readset);
+		rc = select(lh->fd+1, &readset, NULL, NULL, NULL);
+		if (rc <= 0)
+			return rc;
+
+		rc = read(lh->fd, (char *)gmh, rlen);
+		if (rc <= 0)
+			return rc;
+
+		if (gmh->id == id) {
+			/* we've found the matching packet, return to calling function */
+			return rc;
+		} else
+			rc = lgsm_handle_packet(lh, (char *)gmh, rc);
+	}
+}
+
 int lgsm_fd(struct lgsm_handle *lh)
 {
 	return lh->fd;
diff --git a/src/libgsmd/libgsmd_passthrough.c b/src/libgsmd/libgsmd_passthrough.c
new file mode 100644
index 0000000..45ce066
--- /dev/null
+++ b/src/libgsmd/libgsmd_passthrough.c
@@ -0,0 +1,65 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include <sys/types.h>
+
+#include <gsmd/usock.h>
+#include <libgsmd/libgsmd.h>
+
+#include "lgsm_internals.h"
+
+static u_int16_t next_msg_id;
+
+static int lgsm_send(struct lgsm_handle *lh, struct gsmd_msg_hdr *gmh)
+{
+	gmh->id = next_msg_id++;
+	return send(lh->fd, (char *) gmh, sizeof(*gmh) + gmh->len);
+}
+
+#define PT_BUF_SIZE	1024
+static char passthrough_buf[sizeof(struct gsmd_msg_hdr)+PT_BUF_SIZE];
+static char passthrough_rbuf[sizeof(struct gsmd_msg_hdr)+PT_BUF_SIZE];
+
+int lgsm_passthrough(struct lgsm_handle *lh, const char *tx, char *rx, unsigned int *rx_len)
+{
+	struct gsmd_msg_hdr *gmh = (struct gsmd_msg_hdr *)passthrough_buf;
+	struct gsmd_msg_hdr *rgmh = (struct gsmd_msg_hdr *)passthrough_rbuf;
+	char *tx_buf = (char *)gmh + sizeof(*gmh);
+	char *rx_buf = (char *)rgmh + sizeof(*rgmh);
+	int len = strlen(tx);
+	int rc;
+
+	if (len > PT_BUF_SIZE)
+		return -EINVAL;
+
+	gmh->version = GSMD_PROTO_VERSION;
+	gmh->msg_type = GSMD_MSG_PASSTHROUGH;
+	gmh->msg_subtype = GSMD_PASSTHROUGH_REQUEST;
+	gmh->len = len;
+	strcpy(tx_buf, tx);
+
+	rc = lgsm_send(lh, gmh);
+	if (rc < len+sizeof(*gmh))
+		return rc;
+
+	/* since we synchronously want to wait for a response, we need to _internally_ loop over
+	 * incoming packets and call the callbacks for intermediate messages (if applicable) */
+	rc = lgsm_blocking_wait_packet(lh, gmh->id, passthrough_rbuf, sizeof(passthrough_rbuf));
+	if (rc <= 0)
+		return rc;
+
+	if (rc < sizeof(*rgmh))
+		return -EINVAL;
+
+	if (rc < sizeof(*rgmh) + rgmh->len)
+		return -EINVAL;
+	
+	/* FIXME: make sure rx_buf is zero-terminated */
+	strcpy(rx, rx_buf);
+	*rx_len = rgmh->len;
+
+	return rx_len;
+}