[PATCH v13 13/21] net: lwip: add dns command

[Ilias Apalodimas]

On Wed, 16 Oct 2024 at 13:05, Jerome Forissier
<jerome.forissier at linaro.org> wrote:
>
> Add CMD_DNS when NET_LWIP is enabled to provide the dns command using
> lwIP.
>
> Signed-off-by: Jerome Forissier <jerome.forissier at 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 b7d1dd028a1..2791ad5393c 100644
> --- a/cmd/Kconfig
> +++ b/cmd/Kconfig
> @@ -2027,11 +2027,6 @@ 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
> @@ -2079,6 +2074,12 @@ 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_MII
>         bool "mii"
>         imply CMD_MDIO
> 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 9aa371e962c..ff9d03b23e8 100644
> --- a/include/net-lwip.h
> +++ b/include/net-lwip.h
> @@ -17,6 +17,7 @@ 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
>

Acked-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>