1 files changed, 34 insertions, 142 deletions

diff --git a/src/osmo-bts-virtual/virtual_um.c b/src/osmo-bts-virtual/virtual_um.c
index 2126b092..e2e86e44 100644
--- a/src/osmo-bts-virtual/virtual_um.c
+++ b/src/osmo-bts-virtual/virtual_um.c
@@ -19,118 +19,44 @@
  *
  */
 
-#include <unistd.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-#include <netinet/in.h>
-#include <net/if.h>
-
 #include <osmocom/core/select.h>
 #include <osmocom/core/utils.h>
 #include <osmocom/core/socket.h>
 #include <osmocom/core/gsmtap.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/talloc.h>
 
 #include "virtual_um.h"
+#include "osmo_mcast_sock.h"
 
-#define VIRT_UM_MSGB_SIZE	256
-
-static int mcast_join_group(int fd, const char *group, const char *netdev)
-{
-	int ifindex = 0;
-	int rc, af;
-	socklen_t af_len = sizeof(af);
-
-	if (netdev) {
-		ifindex = if_nametoindex(netdev);
-		if (!ifindex)
-			return -1;
-	}
-
-	rc = getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &af, &af_len);
-	if (rc < 0)
-		return rc;
-
-	switch (af) {
-	case AF_INET:
-		{
-			struct ip_mreqn mr;
-			memset(&mr, 0, sizeof(mr));
-			inet_pton(AF_INET, group, &mr.imr_multiaddr);
-			if (ifindex)
-				mr.imr_ifindex = ifindex;
-			rc = setsockopt(fd, SOL_SOCKET, IP_ADD_MEMBERSHIP,
-					&mr, sizeof(mr));
-		}
-		break;
-	case AF_INET6:
-		{
-			struct ipv6_mreq mr;
-			memset(&mr, 0, sizeof(mr));
-			inet_pton(AF_INET6, group, &mr.ipv6mr_multiaddr);
-			if (ifindex)
-				mr.ipv6mr_interface = ifindex;
-			rc = setsockopt(fd, SOL_SOCKET, IPV6_ADD_MEMBERSHIP,
-					&mr, sizeof(mr));
-
-		}
-		break;
-	default:
-		rc = -1;
-		break;
-	}
-
-	return rc;
-}
-
-static int mcast_connect(int fd, const char *group, uint16_t port)
-{
-	int rc, af;
-	socklen_t af_len = sizeof(af);
-	struct sockaddr_in sin;
-	struct sockaddr_in6 sin6;
-
-	rc = getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &af, &af_len);
-	if (rc < 0)
-		return rc;
-
-	switch (af) {
-	case AF_INET:
-		memset(&sin, 0, sizeof(sin));
-		sin.sin_family = AF_INET;
-		sin.sin_port = htons(port);
-		inet_pton(AF_INET, group, &sin.sin_addr);
-		rc = connect(fd, (struct sockaddr *) &sin, sizeof(sin));
-		break;
-	case AF_INET6:
-		memset(&sin6, 0, sizeof(sin6));
-		sin6.sin6_family = AF_INET6;
-		sin6.sin6_port = htons(port);
-		inet_pton(AF_INET6, group, &sin6.sin6_addr);
-		rc = connect(fd, (struct sockaddr *) &sin6, sizeof(sin6));
-		break;
-	default:
-		return -1;
-	}
-
-	return rc;
-}
-
+/**
+ * Virtual UM interface file descriptor callback.
+ * Should be called by select.c when the fd is ready for reading.
+ */
 static int virt_um_fd_cb(struct osmo_fd *ofd, unsigned int what)
 {
 	struct virt_um_inst *vui = ofd->data;
 
+	// check if the read flag is set
 	if (what & BSC_FD_READ) {
-		struct msgb *msg = msgb_alloc(VIRT_UM_MSGB_SIZE, "Virtual UM Rx");
+		// allocate message buffer of specified size
+		struct msgb *msg = msgb_alloc(VIRT_UM_MSGB_SIZE,
+		                "Virtual UM Rx");
 		int rc;
 
-		rc = read(ofd->fd, msgb_data(msg), msgb_tailroom(msg));
+		// read message from fd in message buffer
+		rc = mcast_bidir_sock_rx(vui->mcast_sock, msgb_data(msg),
+		                msgb_tailroom(msg));
+		// rc is number of bytes actually read
 		if (rc > 0) {
 			msgb_put(msg, rc);
+			msg->l1h = msgb_data(msg);
+			// call the l1 callback function for a received msg
 			vui->recv_cb(vui, msg);
 		} else {
+			// TODO: this kind of error handling might be a bit harsh
 			vui->recv_cb(vui, NULL);
+			// Unregister fd from select loop
 			osmo_fd_unregister(ofd);
 			close(ofd->fd);
 			ofd->fd = -1;
@@ -141,70 +67,36 @@ static int virt_um_fd_cb(struct osmo_fd *ofd, unsigned int what)
 	return 0;
 }
 
-struct virt_um_inst *virt_um_init(void *ctx, const char *group, uint16_t port,
-				  const char *netdev, void *priv,
-				  void (*recv_cb)(struct virt_um_inst *vui, struct msgb *msg))
+struct virt_um_inst *virt_um_init(
+                void *ctx, const char *tx_mcast_group, uint16_t tx_mcast_port,
+                const char *rx_mcast_group, uint16_t rx_mcast_port,
+                void (*recv_cb)(struct virt_um_inst *vui, struct msgb *msg))
 {
-	struct virt_um_inst *vui;
-	int fd, rc;
-
-	if (!port)
-		port = GSMTAP_UDP_PORT;
-	if (!group)
-		group = "239.0.47.29";
-
-	/* crate a socked and bind it to the multicast group. Do NOT
-	 * specify a fixed port locally, to make stack choose a random
-	 * free UDP port. */
-	fd = osmo_sock_init(AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, group,
-			    0, OSMO_SOCK_F_BIND);
-	if (fd < 0)
-		return NULL;
-
-	/* join the multicast group */
-	rc = mcast_join_group(fd, group, netdev);
-	if (rc < 0) {
-		close(fd);
-		return NULL;
-	}
-
-	/* and finally also connect */
-	rc = mcast_connect(fd, group, port);
-	if (rc < 0) {
-		close(fd);
-		return NULL;
-	}
-
-	vui = talloc_zero(ctx, struct virt_um_inst);
-	vui->priv = priv;
+	struct virt_um_inst *vui = talloc_zero(ctx, struct virt_um_inst);
+	vui->mcast_sock = mcast_bidir_sock_setup(ctx, tx_mcast_group,
+	                tx_mcast_port, rx_mcast_group, rx_mcast_port, 1,
+	                virt_um_fd_cb, vui);
 	vui->recv_cb = recv_cb;
-	vui->ofd.data = vui;
-	vui->ofd.fd = fd;
-	vui->ofd.when = BSC_FD_READ;
-	vui->ofd.cb = virt_um_fd_cb;
-
-	osmo_fd_register(&vui->ofd);
 
 	return vui;
+
 }
 
 void virt_um_destroy(struct virt_um_inst *vui)
 {
-	struct osmo_fd *ofd = &vui->ofd;
-
-	osmo_fd_unregister(ofd);
-	close(ofd->fd);
-	ofd->fd = -1;
-	ofd->when = 0;
-
+	mcast_bidir_sock_close(vui->mcast_sock);
 	talloc_free(vui);
 }
 
+/**
+ * Write msg to to multicast socket and free msg afterwards
+ */
 int virt_um_write_msg(struct virt_um_inst *vui, struct msgb *msg)
 {
 	int rc;
 
-	rc = write(vui->ofd.fd, msgb_data(msg), msgb_length(msg));
+	rc = mcast_bidir_sock_tx(vui->mcast_sock, msgb_data(msg),
+	                msgb_length(msg));
 	msgb_free(msg);
 
 	return rc;