[PATCH] net/netcat: add netcat over tcp support

1 Jan 2025

This patch adds downloading/uploading of data with netcat utility.
Client/server modes are supported both.
This patch is also an example of using new tcp api for legacy stack.
How to test:
============
  netcat-openbsd=1.219-1 from debian were used for a tests
a) Load data from remote host.
       * U-Boot listen on tcp port 3456
       * PC connects
u-boot: netcat load ${loadaddr} 3456
     PC:     netcat -q1 ${UBOOT_IP} 3456 < image.itb
b) Load data from remote host.
       * PC listen on tcp port 3456
       * U-Boot connects
PC:     netcat -q1 -l -p 3456 < image.itb
     u-boot: netcat load ${loadaddr} ${PC_IP}:3456
c) Save data to remote host
       * U-Boot listen on tcp port 3456
       * PC connects
u-boot: netcat save ${loadaddr} ${data_size_in_hex} 3456
     PC:     netcat -w1 ${UBOOT_IP} 3456 >image.itb
d) Save data to remote host
       * PC listen on tcp port 3456
       * U-Boot connects
PC:     netcat -w1 -l -p 3456 >image.itb
     u-boot: netcat save ${loadaddr} ${data_size_in_hex} ${PC_IP}:3456
Signed-off-by: Mikhail Kshevetskiy mikhail.kshevetskiy@iopsys.eu
Reviewed-by: Simon Glass sjg@chromium.org
---
 cmd/Kconfig          |  10 +++
 cmd/net.c            |  35 ++++++--
 include/net-legacy.h |   2 +-
 include/net/netcat.h |  20 +++++
 net/Makefile         |   1 +
 net/net.c            |   9 ++
 net/netcat.c         | 194 +++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 265 insertions(+), 6 deletions(-)
 create mode 100644 include/net/netcat.h
 create mode 100644 net/netcat.c

diff --git a/cmd/Kconfig b/cmd/Kconfig
index 93efeaec6f4..e37e50a18b5 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -2091,6 +2091,16 @@ config CMD_DNS
    help
      Lookup the IP of a hostname
+config CMD_NETCAT
+	bool "netcat"
+	select PROT_TCP
+	help
+	  netcat is a simple command to load/store kernel, or other files,
+	  using well-known netcat (nc) utility. Unlike classic netcat utility
+	  this command supports TCP-based data transfer only, thus no data
+	  will be lost or reordered. Any netcat implementation should work,
+	  but openbsd one was tested only.
+
 config CMD_MII
    bool "mii"
    imply CMD_MDIO
diff --git a/cmd/net.c b/cmd/net.c
index 79525f73a51..d7a5025f940 100644
--- a/cmd/net.c
+++ b/cmd/net.c
@@ -208,6 +208,29 @@ U_BOOT_CMD(
 );
 #endif
+#if defined(CONFIG_CMD_NETCAT)
+static int do_netcat_load(struct cmd_tbl *cmdtp, int flag, int argc,
+			  char *const argv[])
+{
+	return netboot_common(NETCAT_LOAD, cmdtp, argc, argv);
+}
+
+static int do_netcat_save(struct cmd_tbl *cmdtp, int flag, int argc,
+			  char *const argv[])
+{
+	return netboot_common(NETCAT_SAVE, cmdtp, argc, argv);
+}
+
+U_BOOT_LONGHELP(netcat,
+	"load [loadAddress] [[hostIPaddr:]port]\n"
+	"save Address Size [[hostIPaddr:]port]");
+
+U_BOOT_CMD_WITH_SUBCMDS(netcat,
+	"load/store data over plain TCP via netcat utility", netcat_help_text,
+	U_BOOT_SUBCMD_MKENT(load, 3, 0, do_netcat_load),
+	U_BOOT_SUBCMD_MKENT(save, 4, 0, do_netcat_save));
+#endif
+
 static void netboot_update_env(void)
 {
    char tmp[46];
@@ -325,16 +348,17 @@ static int parse_args(enum proto_t proto, int argc, char *const argv[])
switch (argc) {
    case 1:
-		if (IS_ENABLED(CONFIG_CMD_TFTPPUT) && proto == TFTPPUT)
+		if ((IS_ENABLED(CONFIG_CMD_TFTPPUT) && proto == TFTPPUT) ||
+		    (IS_ENABLED(CONFIG_CMD_NETCAT) && proto == NETCAT_SAVE))
    		return 1;
-
    	/* refresh bootfile name from env */
    	copy_filename(net_boot_file_name, env_get("bootfile"),
    		      sizeof(net_boot_file_name));
    	break;
case 2:
-		if (IS_ENABLED(CONFIG_CMD_TFTPPUT) && proto == TFTPPUT)
+		if ((IS_ENABLED(CONFIG_CMD_TFTPPUT) && proto == TFTPPUT) ||
+		    (IS_ENABLED(CONFIG_CMD_NETCAT) && proto == NETCAT_SAVE))
    		return 1;
    	/*
    	 * Only one arg - accept two forms:
@@ -356,7 +380,8 @@ static int parse_args(enum proto_t proto, int argc, char *const argv[])
    	break;
case 3:
-		if (IS_ENABLED(CONFIG_CMD_TFTPPUT) && proto == TFTPPUT) {
+		if ((IS_ENABLED(CONFIG_CMD_TFTPPUT) && proto == TFTPPUT) ||
+		    (IS_ENABLED(CONFIG_CMD_NETCAT) && proto == NETCAT_SAVE)) {
    		if (parse_addr_size(argv))
    			return 1;
    	} else {
@@ -367,7 +392,7 @@ static int parse_args(enum proto_t proto, int argc, char *const argv[])
    	}
    	break;
-#ifdef CONFIG_CMD_TFTPPUT
+#if defined(CONFIG_CMD_TFTPPUT) || defined(CONFIG_CMD_NETCAT)
    case 4:
    	if (parse_addr_size(argv))
    		return 1;
diff --git a/include/net-legacy.h b/include/net-legacy.h
index bc0f0cde9fe..84a4beb9ec1 100644
--- a/include/net-legacy.h
+++ b/include/net-legacy.h
@@ -305,7 +305,7 @@ extern int		net_restart_wrap;	/* Tried all network devices */
 enum proto_t {
    BOOTP, RARP, ARP, TFTPGET, DHCP, DHCP6, PING, PING6, DNS, NFS, CDP,
    NETCONS, SNTP, TFTPSRV, TFTPPUT, LINKLOCAL, FASTBOOT_UDP, FASTBOOT_TCP,
-	WOL, UDP, NCSI, WGET, RS
+	WOL, UDP, NCSI, WGET, NETCAT_LOAD, NETCAT_SAVE, RS
 };
/* Indicates whether the file name was specified on the command line */
diff --git a/include/net/netcat.h b/include/net/netcat.h
new file mode 100644
index 00000000000..d8e09aaaa55
--- /dev/null
+++ b/include/net/netcat.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: BSD-2-Clause
+ *
+ * netcat include file
+ * Copyright (C) 2024 IOPSYS Software Solutions AB
+ * Author: Mikhail Kshevetskiy mikhail.kshevetskiy@iopsys.eu
+ */
+#ifndef __NET_NETCAT_TCP_H__
+#define __NET_NETCAT_TCP_H__
+
+/**
+ * netcat_load_start() - begin netcat in loading mode
+ */
+void netcat_load_start(void);
+
+/**
+ * netcat_save_start() - begin netcat in data saving mode
+ */
+void netcat_save_start(void);
+
+#endif /* __NET_NETCAT_TCP_H__ */
diff --git a/net/Makefile b/net/Makefile
index 7c917b318c0..bc5f2f123be 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_CMD_WOL)  += wol.o
 obj-$(CONFIG_PROT_UDP) += udp.o
 obj-$(CONFIG_PROT_TCP) += tcp.o
 obj-$(CONFIG_WGET) += wget.o
+obj-$(CONFIG_CMD_NETCAT) += netcat.o
# Disable this warning as it is triggered by:
 # sprintf(buf, index ? "foo%d" : "foo", index)
diff --git a/net/net.c b/net/net.c
index 1828f1cca36..595bffdc532 100644
--- a/net/net.c
+++ b/net/net.c
@@ -103,6 +103,7 @@
 #include <net/fastboot_udp.h>
 #include <net/fastboot_tcp.h>
 #include <net/ncsi.h>
+#include <net/netcat.h>
 #if defined(CONFIG_CMD_PCAP)
 #include <net/pcap.h>
 #endif
@@ -572,6 +573,14 @@ restart:
    		wget_start();
    		break;
 #endif
+#if defined(CONFIG_CMD_NETCAT)
+		case NETCAT_LOAD:
+			netcat_load_start();
+			break;
+		case NETCAT_SAVE:
+			netcat_save_start();
+			break;
+#endif
 #if defined(CONFIG_CMD_CDP)
    	case CDP:
    		cdp_start();
diff --git a/net/netcat.c b/net/netcat.c
new file mode 100644
index 00000000000..47dbebe5ae2
--- /dev/null
+++ b/net/netcat.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * netcat support driver
+ * Copyright (C) 2024 IOPSYS Software Solutions AB
+ * Author: Mikhail Kshevetskiy mikhail.kshevetskiy@iopsys.eu
+ */
+
+#include <command.h>
+#include <display_options.h>
+#include <env.h>
+#include <image.h>
+#include <mapmem.h>
+#include <net.h>
+#include <net/tcp.h>
+#include <net/netcat.h>
+
+#define HASHES_PER_LINE		65
+#define MARKER_STEP		10
+
+static struct in_addr		server_ip;
+static u16			server_port;
+static u16			local_port;
+static int			listen;
+static int			reading;
+static int			marker, marks_in_line;
+static enum net_loop_state	netcat_loop_state;
+
+static void show_block_marker(int packets)
+{
+	for (; marker + MARKER_STEP <= packets; marker += MARKER_STEP) {
+		marks_in_line++;
+		putc('#');
+		if (marks_in_line == HASHES_PER_LINE) {
+			marks_in_line = 0;
+			puts("\n");
+		}
+	}
+}
+
+static void tcp_stream_on_closed(struct tcp_stream *tcp)
+{
+	if (tcp->status != TCP_ERR_OK)
+		netcat_loop_state = NETLOOP_FAIL;
+
+	/*
+	 * The status line will be shown after the download/upload
+	 * progress (see show_block_marker() function). This progress
+	 * generally have no final "\n", so jump to new line before
+	 * output the status
+	 */
+	if (netcat_loop_state != NETLOOP_SUCCESS) {
+		net_boot_file_size = 0;
+		printf("\nnetcat: Transfer Fail, TCP status - %d\n", tcp->status);
+	} else {
+		env_set_hex("filesize", net_boot_file_size);
+		printf("\nPackets %s %d, Transfer Successful\n",
+		       reading ? "received" : "transmitted",
+		       reading ? tcp->rx_packets : tcp->tx_packets);
+	}
+	net_set_state(netcat_loop_state);
+}
+
+static void tcp_stream_on_rcv_nxt_update(struct tcp_stream *tcp, u32 rx_bytes)
+{
+	net_boot_file_size = rx_bytes;
+	show_block_marker(tcp->rx_packets);
+}
+
+static void tcp_stream_on_snd_una_update(struct tcp_stream *tcp, u32 tx_bytes)
+{
+	show_block_marker(tcp->tx_packets);
+	if (tx_bytes == image_save_size)
+		tcp_stream_close(tcp);
+}
+
+static void tcp_stream_on_established(struct tcp_stream *tcp)
+{
+	netcat_loop_state = NETLOOP_SUCCESS;
+}
+
+static int tcp_stream_rx(struct tcp_stream *tcp, u32 rx_offs, void *buf, int len)
+{
+	void *ptr;
+
+	ptr = map_sysmem(image_load_addr + rx_offs, len);
+	memcpy(ptr, buf, len);
+	unmap_sysmem(ptr);
+
+	return len;
+}
+
+static int tcp_stream_tx(struct tcp_stream *tcp, u32 tx_offs, void *buf, int maxlen)
+{
+	void *ptr;
+
+	if (tx_offs + maxlen > image_save_size)
+		maxlen = image_save_size - tx_offs;
+	if (!maxlen)
+		return 0;
+
+	ptr = map_sysmem(image_save_addr + tx_offs, maxlen);
+	memcpy(buf, ptr, maxlen);
+	unmap_sysmem(ptr);
+
+	return maxlen;
+}
+
+/*
+ * This function will be called on new connections (incoming or outgoing)
+ * It MUST:
+ *   -- setup required tcp_stream callbacks (if connection will be accepted)
+ *   -- return a connection verdict:
+ *        0: discard connection
+ *        1: accept connection
+ */
+static int tcp_stream_on_create(struct tcp_stream *tcp)
+{
+	if (listen) {
+		/*
+		 * We are listening for incoming connections.
+		 * Accept connections to netcat listen port only.
+		 */
+		if (tcp->lport != local_port)
+			return 0;
+	} else {
+		/*
+		 * We are connecting to remote host.
+		 * Check remote IP:port to make sure that this is our connection
+		 */
+		if (tcp->rhost.s_addr != server_ip.s_addr ||
+		    tcp->rport != server_port)
+			return 0;
+	}
+
+	netcat_loop_state = NETLOOP_FAIL;
+	net_boot_file_size = 0;
+	marker = 0;
+	marks_in_line = 0;
+
+	tcp->on_closed = tcp_stream_on_closed;
+	tcp->on_established = tcp_stream_on_established;
+	if (reading) {
+		tcp->on_rcv_nxt_update = tcp_stream_on_rcv_nxt_update;
+		tcp->rx = tcp_stream_rx;
+	} else {
+		tcp->on_snd_una_update = tcp_stream_on_snd_una_update;
+		tcp->tx = tcp_stream_tx;
+	}
+
+	return 1;
+}
+
+static void netcat_start(void)
+{
+	struct tcp_stream *tcp;
+
+	memset(net_server_ethaddr, 0, 6);
+	tcp_stream_set_on_create_handler(tcp_stream_on_create);
+
+	if (!strchr(net_boot_file_name, ':')) {
+		listen = 1;
+		printf("Listening on port %s...\n", net_boot_file_name);
+
+		local_port = dectoul(net_boot_file_name, NULL);
+	} else {
+		listen = 0;
+		printf("Connecting to %s...\n", net_boot_file_name);
+
+		server_ip = string_to_ip(net_boot_file_name);
+		server_port = dectoul(strchr(net_boot_file_name, ':') + 1, NULL);
+
+		tcp = tcp_stream_connect(server_ip, server_port);
+		if (!tcp) {
+			printf("No free tcp streams\n");
+			net_set_state(NETLOOP_FAIL);
+			return;
+		}
+		tcp_stream_put(tcp);
+	}
+}
+
+void netcat_load_start(void)
+{
+	reading = 1;
+
+	return netcat_start();
+}
+
+void netcat_save_start(void)
+{
+	reading = 0;
+
+	return netcat_start();
+}
-- 
2.45.2


    