[PATCH v5 11/20] net-lwip: add dns command

Jerome Forissier
2024-07-25T12:59:48Z

Add CMD_DNS when NET_LWIP is enabled to provide the dns command using
lwIP.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
---
cmd/Kconfig | 11 ++--
cmd/net-lwip.c | 8 +++
include/net-lwip.h | 1 +
net/lwip/Makefile | 1 +
net/lwip/dns.c | 127 +++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 143 insertions(+), 5 deletions(-)
create mode 100644 net/lwip/dns.c

diff --git a/cmd/Kconfig b/cmd/Kconfig
index 21188a763cf..a862b6415dd 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -2034,11 +2034,6 @@ config CMD_SNTP
help
Synchronize RTC via network

-config CMD_DNS
- bool "dns"
- help
- Lookup the IP of a hostname
-
config CMD_LINK_LOCAL
bool "linklocal"
select LIB_RAND
@@ -2093,6 +2088,12 @@ config CMD_DHCP
help
Boot image via network using DHCP/TFTP protocol

+config CMD_DNS
+ bool "dns"
+ select PROT_DNS_LWIP if NET_LWIP
+ help
+ Lookup the IP of a hostname
+
config CMD_PING
bool "ping"
select PROT_RAW_LWIP if NET_LWIP
diff --git a/cmd/net-lwip.c b/cmd/net-lwip.c
index feed719beef..c021da6a674 100644
--- a/cmd/net-lwip.c
+++ b/cmd/net-lwip.c
@@ -27,3 +27,11 @@ U_BOOT_CMD(
"[loadAddress] [[hostIPaddr:]bootfilename]"
);
#endif
+
+#if defined(CONFIG_CMD_DNS)
+U_BOOT_CMD(
+ dns, 3, 1, do_dns,
+ "lookup the IP of a hostname",
+ "hostname [envvar]"
+);
+#endif
diff --git a/include/net-lwip.h b/include/net-lwip.h
index 58640c04a7f..cb60537f9f3 100644
--- a/include/net-lwip.h
+++ b/include/net-lwip.h
@@ -13,6 +13,7 @@ struct netif *net_lwip_get_netif(void);
int net_lwip_rx(struct udevice *udev, struct netif *netif);

int do_dhcp(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]);
+int do_dns(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]);
int do_ping(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]);

#endif /* __NET_LWIP_H__ */
diff --git a/net/lwip/Makefile b/net/lwip/Makefile
index b5af37a9b18..645d8a8c457 100644
--- a/net/lwip/Makefile
+++ b/net/lwip/Makefile
@@ -2,5 +2,6 @@ ccflags-y += -I$(srctree)/lib/lwip/lwip/src/include -I$(srctree)/lib/lwip/u-boot

obj-$(CONFIG_$(SPL_)DM_ETH) += net-lwip.o
obj-$(CONFIG_CMD_DHCP) += dhcp.o
+obj-$(CONFIG_CMD_DNS) += dns.o
obj-$(CONFIG_CMD_PING) += ping.o
obj-$(CONFIG_CMD_TFTPBOOT) += tftp.o
diff --git a/net/lwip/dns.c b/net/lwip/dns.c
new file mode 100644
index 00000000000..4b937feaee1
--- /dev/null
+++ b/net/lwip/dns.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (C) 2024 Linaro Ltd. */
+
+#include <command.h>
+#include <console.h>
+#include <lwip/dns.h>
+#include <lwip/timeouts.h>
+#include <net.h>
+#include <time.h>
+
+#define DNS_RESEND_MS 1000
+#define DNS_TIMEOUT_MS 10000
+
+struct dns_cb_arg {
+ ip_addr_t host_ipaddr;
+ const char *var;
+ bool done;
+};
+
+static void do_dns_tmr(void *arg)
+{
+ dns_tmr();
+}
+
+static void dns_cb(const char *name, const ip_addr_t *ipaddr, void *arg)
+{
+ struct dns_cb_arg *dns_cb_arg = arg;
+ char *ipstr = ip4addr_ntoa(ipaddr);
+
+ dns_cb_arg->done = true;
+
+ if (!ipaddr) {
+ printf("DNS: host not found\n");
+ dns_cb_arg->host_ipaddr.addr = 0;
+ return;
+ }
+
+ if (dns_cb_arg->var)
+ env_set(dns_cb_arg->var, ipstr);
+
+ printf("%s\n", ipstr);
+}
+
+static int dns_loop(struct udevice *udev, const char *name, const char *var)
+{
+ struct dns_cb_arg dns_cb_arg = { };
+ bool has_server = false;
+ struct netif *netif;
+ ip_addr_t ipaddr;
+ ip_addr_t ns;
+ ulong start;
+ char *nsenv;
+ int ret;
+
+ dns_cb_arg.var = var;
+
+ netif = net_lwip_new_netif(udev);
+ if (!netif)
+ return -1;
+
+ dns_init();
+
+ nsenv = env_get("dnsip");
+ if (nsenv && ipaddr_aton(nsenv, &ns)) {
+ dns_setserver(0, &ns);
+ has_server = true;
+ }
+
+ nsenv = env_get("dnsip2");
+ if (nsenv && ipaddr_aton(nsenv, &ns)) {
+ dns_setserver(1, &ns);
+ has_server = true;
+ }
+
+ if (!has_server) {
+ log_err("No valid name server (dnsip/dnsip2)\n");
+ net_lwip_remove_netif(netif);
+ return CMD_RET_FAILURE;
+ }
+
+ dns_cb_arg.done = false;
+
+ ret = dns_gethostbyname(name, &ipaddr, dns_cb, &dns_cb_arg);
+
+ if (ret == ERR_OK) {
+ dns_cb(name, &ipaddr, &dns_cb_arg);
+ } else if (ret == ERR_INPROGRESS) {
+ start = get_timer(0);
+ sys_timeout(DNS_RESEND_MS, do_dns_tmr, NULL);
+ do {
+ net_lwip_rx(udev, netif);
+ if (dns_cb_arg.done)
+ break;
+ sys_check_timeouts();
+ if (ctrlc()) {
+ printf("\nAbort\n");
+ break;
+ }
+ } while (get_timer(start) < DNS_TIMEOUT_MS);
+ sys_untimeout(do_dns_tmr, NULL);
+ }
+
+ net_lwip_remove_netif(netif);
+
+ if (dns_cb_arg.done && dns_cb_arg.host_ipaddr.addr != 0)
+ return CMD_RET_SUCCESS;
+
+ return CMD_RET_FAILURE;
+}
+
+int do_dns(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
+{
+ char *name;
+ char *var = NULL;
+
+ if (argc == 1 || argc > 3)
+ return CMD_RET_USAGE;
+
+ name = argv[1];
+
+ if (argc == 3)
+ var = argv[2];
+
+ eth_set_current();
+
+ return dns_loop(eth_get_dev(), name, var);
+}
--
2.40.1