[PATCH v1] commands: Add `ip` command for listing interfaces, addresses, and routes

[Oleksij Rempel]

This patch introduces the `ip` command, providing functionality similar
to Linux’s `ip` tool, catering to users with strong Linux muscle memory.
It supports:

- `ip l` / `ip link`   - Show network interfaces (state, MAC address)
- `ip a` / `ip addr`   - Show assigned IP addresses and netmasks
- `ip r` / `ip route`  - Show routing table, including default gateway,
                         interface-specific routes, DNS, and server IP.

Signed-off-by: Oleksij Rempel <o.rempel at pengutronix.de>
---
 commands/Kconfig  |   9 +++
 commands/Makefile |   1 +
 commands/ip.c     | 157 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 167 insertions(+)
 create mode 100644 commands/ip.c

diff --git a/commands/Kconfig b/commands/Kconfig
index e41625e294c9..528b30b8fc90 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig
@@ -1397,6 +1397,15 @@ config CMD_TFTP
 	  Options:
 		  -p	push to TFTP server
 
+config CMD_IP
+	tristate
+	prompt "ip"
+	default y
+	help
+          This command provides information about network interfaces, similar
+	  to the Linux `ip addr show` command. It lists interface names, states
+	  (UP/DOWN), MAC addresses, and assigned IP addresses.
+
 config CMD_IP_ROUTE_GET
 	tristate
 	prompt "ip-route-get"
diff --git a/commands/Makefile b/commands/Makefile
index e152e4148b04..c202cdef5703 100644
--- a/commands/Makefile
+++ b/commands/Makefile
@@ -146,6 +146,7 @@ obj-$(CONFIG_CMD_MMC)		+= mmc.o
 obj-$(CONFIG_CMD_MMC_EXTCSD)	+= mmc_extcsd.o
 obj-$(CONFIG_CMD_NAND_BITFLIP)	+= nand-bitflip.o
 obj-$(CONFIG_CMD_SEED)		+= seed.o
+obj-$(CONFIG_CMD_IP)		+= ip.o
 obj-$(CONFIG_CMD_IP_ROUTE_GET)  += ip-route-get.o
 obj-$(CONFIG_CMD_BTHREAD)	+= bthread.o
 obj-$(CONFIG_CMD_UBSAN)		+= ubsan.o
diff --git a/commands/ip.c b/commands/ip.c
new file mode 100644
index 000000000000..35fc5f4d300f
--- /dev/null
+++ b/commands/ip.c
@@ -0,0 +1,157 @@
+#include <common.h>
+#include <command.h>
+#include <net.h>
+#include <linux/list.h>
+#include <complete.h>
+
+/* Function to calculate CIDR prefix from netmask */
+static int netmask_to_prefix(IPaddr_t netmask)
+{
+	int prefix = 0;
+
+	while (netmask) {
+		prefix += netmask & 1;
+		netmask >>= 1;
+	}
+
+	return prefix;
+}
+
+/* Function to display network links (`ip l`) */
+static int do_ip_link(int argc, char *argv[])
+{
+	struct eth_device *edev;
+
+	for_each_netdev(edev) {
+		const char *phy_status = edev->phydev ?
+			(edev->phydev->link ? ",LOWER_UP" : ",NO-CARRIER") : "";
+
+		printf("%s: <%s%s>\n",
+			   eth_name(edev),
+			   edev->active ? "UP" : "DOWN",
+			   phy_status);
+
+		printf("	link/ether %pM brd ff:ff:ff:ff:ff:ff\n",
+		       edev->ethaddr);
+	}
+
+	return 0;
+}
+
+/* Function to display network addresses (`ip a`) */
+static int do_ip_addr(int argc, char *argv[])
+{
+	struct eth_device *edev;
+
+	for_each_netdev(edev) {
+		IPaddr_t ipaddr = net_get_ip(edev);
+		int prefix_length = netmask_to_prefix(edev->netmask);
+		const char *phy_status = edev->phydev ?
+			(edev->phydev->link ? ",LOWER_UP" : ",NO-CARRIER") : "";
+
+		printf("%s: <%s%s>\n", eth_name(edev),
+		       edev->active ? "UP" : "DOWN", phy_status);
+
+		printf("	link/ether %pM brd ff:ff:ff:ff:ff:ff\n",
+		       edev->ethaddr);
+
+		if (ipaddr) {
+			printf("	inet %pI4/%d scope global src %pI4\n",
+				   &ipaddr, prefix_length, &ipaddr);
+		}
+	}
+
+	return 0;
+}
+
+/* Function to display network routes (`ip r`) */
+static int do_ip_route(int argc, char *argv[])
+{
+	const char *domainname = net_get_domainname();
+	IPaddr_t nameserver = net_get_nameserver();
+	const char *serverip = net_get_server();
+	IPaddr_t gateway = net_get_gateway();
+	struct eth_device *edev;
+
+	for_each_netdev(edev) {
+		int prefix_length = netmask_to_prefix(edev->netmask);
+		IPaddr_t ipaddr = net_get_ip(edev);
+		const char *proto;
+
+		/* Skip interfaces without an IP address */
+		if (!ipaddr)
+			continue;
+
+		/* Determine protocol: DHCP or Static */
+		if (edev->global_mode == ETH_MODE_DHCP)
+			proto = "dhcp";
+		else
+			proto = "static";
+
+		/* Show default gateway */
+		if (gateway) {
+			printf("default via %pI4 dev %s proto %s src %pI4\n",
+				   &gateway, eth_name(edev), proto, &ipaddr);
+		}
+
+		/* Show per-interface network route */
+		if (prefix_length > 0) {
+			printf("%pI4/%d dev %s proto kernel scope link src %pI4\n",
+				   &ipaddr, prefix_length, eth_name(edev),
+				   &ipaddr);
+		}
+	}
+
+	/* Show boot server */
+	if (serverip && *serverip) {
+		printf("serverip %s\n", serverip);
+	}
+
+	/* Show DNS server */
+	if (nameserver) {
+		printf("nameserver %pI4\n", &nameserver);
+	}
+
+	/* Show search domain */
+	if (domainname && *domainname) {
+		printf("search %s\n", domainname);
+	}
+
+	return 0;
+}
+
+/* Main IP command dispatcher */
+static int do_ip(int argc, char *argv[])
+{
+	if (argc < 2) {
+		return do_ip_addr(argc, argv); /* Default: `ip a` */
+	}
+
+	if (!strcmp(argv[1], "l") || !strcmp(argv[1], "link"))
+		return do_ip_link(argc, argv);
+	else if (!strcmp(argv[1], "a") || !strcmp(argv[1], "addr"))
+		return do_ip_addr(argc, argv);
+	else if (!strcmp(argv[1], "r") || !strcmp(argv[1], "route"))
+		return do_ip_route(argc, argv);
+
+	printf("Usage: ip [l|link] | [a|addr] | [r|route]\n");
+	return 1;
+}
+
+BAREBOX_CMD_HELP_START(ip)
+BAREBOX_CMD_HELP_TEXT("Show network interfaces, addresses, and routes")
+BAREBOX_CMD_HELP_TEXT("")
+BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT("l, link", "Show only network links (interface state and MAC)")
+BAREBOX_CMD_HELP_OPT("a, addr", "Show only network addresses (default behavior)")
+BAREBOX_CMD_HELP_OPT("r, route", "Show routing information (default gateway, network routes, server IP, DNS)")
+BAREBOX_CMD_HELP_END
+
+BAREBOX_CMD_START(ip)
+	.cmd		= do_ip,
+	BAREBOX_CMD_DESC("Show network interfaces, addresses, and routes")
+	BAREBOX_CMD_OPTS("[l|link] | [a|addr] | [r|route]")
+	BAREBOX_CMD_GROUP(CMD_GRP_MISC)
+	BAREBOX_CMD_COMPLETE(empty_complete)
+	BAREBOX_CMD_HELP(cmd_ip_help)
+BAREBOX_CMD_END
-- 
2.39.5