net: add fastboot TCP support

Known limitations are
1. fastboot reboot doesn't work (answering OK but not rebooting)
2. flashing isn't supported (TCP transport only limitation)

The command syntax is
fastboot tcp

Signed-off-by: Dmitrii Merkurev <dimorinny@google.com>
Cc: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Cc: Simon Glass <sjg@chromium.org>
Сс: Joe Hershberger <joe.hershberger@ni.com>
Сс: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 143 insertions, 0 deletions

diff --git a/net/fastboot_tcp.c b/net/fastboot_tcp.c
new file mode 100644
index 0000000000..b5613b6aa2
--- /dev/null
+++ b/net/fastboot_tcp.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ */
+
+#include <common.h>
+#include <fastboot.h>
+#include <net.h>
+#include <net/fastboot_tcp.h>
+#include <net/tcp.h>
+
+static char command[FASTBOOT_COMMAND_LEN] = {0};
+static char response[FASTBOOT_RESPONSE_LEN] = {0};
+
+static const unsigned short handshake_length = 4;
+static const uchar *handshake = "FB01";
+
+static u16 curr_sport;
+static u16 curr_dport;
+static u32 curr_tcp_seq_num;
+static u32 curr_tcp_ack_num;
+static unsigned int curr_request_len;
+static enum fastboot_tcp_state {
+	FASTBOOT_CLOSED,
+	FASTBOOT_CONNECTED,
+	FASTBOOT_DISCONNECTING
+} state = FASTBOOT_CLOSED;
+
+static void fastboot_tcp_answer(u8 action, unsigned int len)
+{
+	const u32 response_seq_num = curr_tcp_ack_num;
+	const u32 response_ack_num = curr_tcp_seq_num +
+		  (curr_request_len > 0 ? curr_request_len : 1);
+
+	net_send_tcp_packet(len, htons(curr_sport), htons(curr_dport),
+			    action, response_seq_num, response_ack_num);
+}
+
+static void fastboot_tcp_reset(void)
+{
+	fastboot_tcp_answer(TCP_RST, 0);
+	state = FASTBOOT_CLOSED;
+}
+
+static void fastboot_tcp_send_packet(u8 action, const uchar *data, unsigned int len)
+{
+	uchar *pkt = net_get_async_tx_pkt_buf();
+
+	memset(pkt, '\0', PKTSIZE);
+	pkt += net_eth_hdr_size() + IP_TCP_HDR_SIZE + TCP_TSOPT_SIZE + 2;
+	memcpy(pkt, data, len);
+	fastboot_tcp_answer(action, len);
+	memset(pkt, '\0', PKTSIZE);
+}
+
+static void fastboot_tcp_send_message(const char *message, unsigned int len)
+{
+	__be64 len_be = __cpu_to_be64(len);
+	uchar *pkt = net_get_async_tx_pkt_buf();
+
+	memset(pkt, '\0', PKTSIZE);
+	pkt += net_eth_hdr_size() + IP_TCP_HDR_SIZE + TCP_TSOPT_SIZE + 2;
+	// Put first 8 bytes as a big endian message length
+	memcpy(pkt, &len_be, 8);
+	pkt += 8;
+	memcpy(pkt, message, len);
+	fastboot_tcp_answer(TCP_ACK | TCP_PUSH, len + 8);
+	memset(pkt, '\0', PKTSIZE);
+}
+
+static void fastboot_tcp_handler_ipv4(uchar *pkt, u16 dport,
+				      struct in_addr sip, u16 sport,
+				      u32 tcp_seq_num, u32 tcp_ack_num,
+				      u8 action, unsigned int len)
+{
+	u64 command_size;
+	u8 tcp_fin = action & TCP_FIN;
+	u8 tcp_push = action & TCP_PUSH;
+
+	curr_sport = sport;
+	curr_dport = dport;
+	curr_tcp_seq_num = tcp_seq_num;
+	curr_tcp_ack_num = tcp_ack_num;
+	curr_request_len = len;
+
+	switch (state) {
+	case FASTBOOT_CLOSED:
+		if (tcp_push) {
+			if (len != handshake_length ||
+			    strlen(pkt) != handshake_length ||
+			    memcmp(pkt, handshake, handshake_length) != 0) {
+				fastboot_tcp_reset();
+				break;
+			}
+			fastboot_tcp_send_packet(TCP_ACK | TCP_PUSH,
+						 handshake, handshake_length);
+			state = FASTBOOT_CONNECTED;
+		}
+		break;
+	case FASTBOOT_CONNECTED:
+		if (tcp_fin) {
+			fastboot_tcp_answer(TCP_FIN | TCP_ACK, 0);
+			state = FASTBOOT_DISCONNECTING;
+			break;
+		}
+		if (tcp_push) {
+			// First 8 bytes is big endian message length
+			command_size = __be64_to_cpu(*(u64 *)pkt);
+			len -= 8;
+			pkt += 8;
+
+			// Only single packet messages are supported ATM
+			if (strlen(pkt) != command_size) {
+				fastboot_tcp_reset();
+				break;
+			}
+			strlcpy(command, pkt, len + 1);
+			fastboot_handle_command(command, response);
+			fastboot_tcp_send_message(response, strlen(response));
+		}
+		break;
+	case FASTBOOT_DISCONNECTING:
+		if (tcp_push)
+			state = FASTBOOT_CLOSED;
+		break;
+	}
+
+	memset(command, 0, FASTBOOT_COMMAND_LEN);
+	memset(response, 0, FASTBOOT_RESPONSE_LEN);
+	curr_sport = 0;
+	curr_dport = 0;
+	curr_tcp_seq_num = 0;
+	curr_tcp_ack_num = 0;
+	curr_request_len = 0;
+}
+
+void fastboot_tcp_start_server(void)
+{
+	printf("Using %s device\n", eth_get_name());
+	printf("Listening for fastboot command on tcp %pI4\n", &net_ip);
+
+	tcp_set_tcp_handler(fastboot_tcp_handler_ipv4);
+}