WIP: handle packets from the TUN device in digipeater

This is only a backup commit.

impl/setup_tundev.sh

@@ -13,7 +13,7 @@ HOSTID="$1"
 
 DEV=hamnet70
 
-sudo ip tuntap add dev $DEV mode tun user $(whoami)
+sudo ip tuntap add dev $DEV mode tun pi user $(whoami)
 sudo ip link set dev $DEV txqueuelen 16  # default is 500
 sudo ip link set dev $DEV up
 sudo ip address add dev $DEV fd73::$HOSTID/64

impl/src/layer2/connection_list.c

@@ -3,6 +3,7 @@
 
 #include "connection_list.h"
 
+#include "layer2/connection.h"
 #include "results.h"
 
 #define SEQ_NR_MASK 0xF
@@ -177,3 +178,23 @@ result_t connection_list_delete_closed(connection_list_t *list)
 
 	return OK;
 }
+
+
+bool connection_list_can_enqueue_packet(connection_list_t *list)
+{
+	if(!list->head) {
+		return false; // no entries -> no free space
+	}
+
+	connection_list_entry_t *entry = list->head;
+
+	while(entry) {
+		if(!connection_can_enqueue_packet(&entry->connection)) {
+			return false;
+		}
+
+		entry = entry->next;
+	}
+
+	return true;
+}

impl/src/layer2/connection_list.h

@@ -83,4 +83,10 @@ result_t connection_list_delete_head(connection_list_t *list);
  */
 result_t connection_list_delete_closed(connection_list_t *list);
 
+/*!\brief Determine if a packet can be enqueued in all queues.
+ *
+ * \returns False if any queue is full, true otherwise.
+ */
+bool connection_list_can_enqueue_packet(connection_list_t *list);
+
 #endif // CONNECTION_LIST_H

impl/src/layer2/digipeater.c

@@ -1,4 +1,7 @@
-#include "layer2/packet_queue.h"
+#include <poll.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
 
 #define LOGGER_MODULE_NAME "digi"
 #include "logger.h"
@@ -10,6 +13,7 @@
 #include "layer2/connection_list.h"
 #include "layer2/ham64.h"
 #include "layer2/packet_structs.h"
+#include "layer2/packet_queue.h"
 #include "results.h"
 #include "utils.h"
 
@@ -175,6 +179,54 @@ result_t digipeater_handle_packet(digipeater_ctx_t *ctx, const uint8_t *buf, siz
 }
 
 
+result_t digipeater_fill_packet_queues_from_tundev(digipeater_ctx_t *ctx, int tun_fd)
+{
+	// first check if any queue is already full, so we don't have to drop packets
+	// from the TUN device queue.
+	if(!connection_list_can_enqueue_packet(&ctx->conn_list)) {
+		LOG(LVL_DEBUG, "No free space in queues.");
+		return OK; // do nothing
+	}
+
+	struct pollfd pfd_tun;
+	memset(&pfd_tun, 0, sizeof(pfd_tun));
+
+	pfd_tun.fd = tun_fd;
+	pfd_tun.events = POLLIN;
+
+	while(true) {
+		int ret = poll(&pfd_tun, 1, 0 /* timeout */);
+		if(ret < 0) {
+			LOG(LVL_ERR, "poll: %s", strerror(errno));
+			return ERR_SYSCALL;
+		} else if(ret == 0) {
+			// no more packets
+			break;
+		} else {
+			// a packet is available -> read it
+			static const size_t packetbuf_size = 2048;
+			uint8_t packetbuf[packetbuf_size];
+			ret = read(tun_fd, packetbuf, packetbuf_size);
+			if(ret < 0) {
+				LOG(LVL_ERR, "read: %s", strerror(errno));
+				return ERR_SYSCALL;
+			} else if(ret == 0) {
+				// no more data, should not happen
+				break;
+			}
+
+			LOG(LVL_DUMP, "TUN Flags: 0x%04x", *(uint16_t*)packetbuf);
+			LOG(LVL_DUMP, "TUN Proto: 0x%04x", *((uint16_t*)packetbuf + 1));
+
+			// FIXME:
+			//ERR_CHECK(connection_list_enqueue_packet(entry->connection, packetbuf, ret));
+		}
+	}
+
+	return OK;
+}
+
+
 size_t digipeater_encode_next_packet(digipeater_ctx_t *ctx, uint8_t *buf, size_t buf_len, bool *end_burst)
 {
 	uint64_t now = get_hires_time();

impl/test/layer2_over_udp/l2udptest_client.c

@@ -260,6 +260,9 @@ int main(int argc, char **argv)
 					break;
 				}
 
+				LOG(LVL_DUMP, "TUN Flags: 0x%04x", *(uint16_t*)packetbuf);
+				LOG(LVL_DUMP, "TUN Proto: 0x%04x", *((uint16_t*)packetbuf + 1));
+
 				RESULT_CHECK(connection_enqueue_packet(&l2conn, packetbuf, ret));
 			}
 		}