From 898b2e8cba94bb08771366aae8ba3ec83ff62409 Mon Sep 17 00:00:00 2001
From: Peter McGoron <code@mcgoron.com>
Date: Mon, 1 Aug 2022 14:44:09 -0400
Subject: [PATCH] ethernet communication

---
 software/CMakeLists.txt      |   3 +-
 software/prj.conf            |  18 ++++++
 software/src/test_ethernet.c | 120 +++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+), 1 deletion(-)
 create mode 100644 software/src/test_ethernet.c

diff --git a/software/CMakeLists.txt b/software/CMakeLists.txt
index a767307..1de1814 100644
--- a/software/CMakeLists.txt
+++ b/software/CMakeLists.txt
@@ -4,4 +4,5 @@ find_package(Zephyr)
 project(cryosnom1)
 include_directories("../firmware")
 
-target_sources(app PRIVATE src/io.c src/test_dac_adc_main.c)
+# target_sources(app PRIVATE src/io.c src/test_dac_adc_main.c)
+target_sources(app PRIVATE src/test_ethernet.c)
diff --git a/software/prj.conf b/software/prj.conf
index 1186b44..b4c474e 100644
--- a/software/prj.conf
+++ b/software/prj.conf
@@ -1,3 +1,21 @@
 CONFIG_LOG=y
+CONFIG_NET_LOG=y
 CONFIG_LOG_BUFFER_SIZE=1024
 CONFIG_LOG_PRINTK=y
+
+CONFIG_NETWORKING=y
+CONFIG_NET_IPV4=y
+CONFIG_NET_IPV6=n
+CONFIG_NET_TCP=y
+CONFIG_NET_SOCKETS=y
+CONFIG_NET_ARP=y
+CONFIG_NET_UDP=y
+CONFIG_NET_DHCPV4=y
+
+CONFIG_INIT_STACKS=y
+
+CONFIG_NET_CONFIG_SETTINGS=y
+CONFIG_NET_CONFIG_NEED_IPV4=y
+CONFIG_NET_MGMT=y
+CONFIG_NET_MGMT_EVENT=y
+CONFIG_TEST_RANDOM_GENERATOR=y
diff --git a/software/src/test_ethernet.c b/software/src/test_ethernet.c
new file mode 100644
index 0000000..c9f0d06
--- /dev/null
+++ b/software/src/test_ethernet.c
@@ -0,0 +1,120 @@
+#include <errno.h>
+#include <zephyr/net/socket.h>
+#include <zephyr/zephyr.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(test_ethernet);
+
+#define PORT 6626
+
+static int
+ip_init(void)
+{
+	int sock;
+
+	sock = zsock_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+
+	if (sock < 0) {
+		LOG_ERR("error: socket: %d", sock);
+		k_fatal_halt(K_ERR_KERNEL_PANIC);
+	}
+
+	struct sockaddr_in addr = {
+		.sin_family = AF_INET,
+		.sin_addr = {.s_addr = htonl(INADDR_ANY)},
+		.sin_port = htons(PORT)
+	};
+
+	if (zsock_bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+		LOG_ERR("error: bind: %d", errno);
+		k_fatal_halt(K_ERR_KERNEL_PANIC);
+	}
+
+	if (zsock_listen(sock, 2) < 0) {
+		LOG_ERR("error: listen: %d", errno);
+		k_fatal_halt(K_ERR_KERNEL_PANIC);
+	}
+
+	return sock;
+}
+
+static int
+get_client(int server)
+{
+	int client;
+	struct sockaddr_in addr;
+	socklen_t len = sizeof(addr);
+
+	do {
+		client = zsock_accept(server, (struct sockaddr *)&addr, &len);
+		if (client < 0)
+			LOG_WRN("error in accept: %d", errno);
+	} while (client < 0);
+
+	char ipaddr[32];
+	zsock_inet_ntop(addr.sin_family, &addr.sin_addr, ipaddr, sizeof(ipaddr));
+	LOG_PRINTK("Connection: %s\n", ipaddr);
+	return client;
+}
+
+static int
+send_all(int sock, char *buf, int len)
+{
+	do {
+		int sent = zsock_send(sock, buf, len, 0);
+		if (sent < 0) {
+			LOG_WRN("error in send: %d", errno);
+			return 0;
+		}
+		buf += sent;
+		len -= sent;
+	} while (len > 0);
+	return 1;
+}
+
+static void
+print_buf_escaped(const char *buf, size_t len)
+{
+	for (size_t i = 0; i < len; i++) {
+		if (*buf < 0x20 || *buf >= 0x7F)
+			LOG_PRINTK("[%02x]", *buf);
+		else
+			LOG_PRINTK("%c", *buf);
+	}
+}
+
+static void
+client_comm(int sock)
+{
+	for (;;) {
+		char buf[256];
+		ssize_t len = zsock_recv(sock, buf, sizeof(buf), 0);
+
+		if (len < 0) {
+			LOG_WRN("Error in client socket: %d", errno);
+			return;
+		} else if (len == 0) {
+			LOG_INF("Client disconnected");
+			return;
+		}
+		print_buf_escaped(buf, len);
+		if (!send_all(sock, buf, len))
+			return;
+	}
+}
+
+/* DHCP is done before main(), so no manual DHCP setup required. */
+
+void
+main(void)
+{
+	LOG_PRINTK("Init test server...\n");
+	int server_sock = ip_init();
+	LOG_PRINTK("Test server waiting on %d\n", PORT);
+
+	for (;;) {
+		int client_sock = get_client(server_sock);
+		client_comm(client_sock);
+		zsock_close(client_sock);
+	}
+}