On Fri, Sep 08, 2023 at 07:53:08PM +0600, Maxim Uvarov wrote:
> U-Boot recently got support for an alternative network stack using LWIP.
> Replace dns command with the LWIP variant while keeping the output and
> error messages identical.
>
> Signed-off-by: Maxim Uvarov <maxim.uva...@linaro.org>
> ---
> include/net/lwip.h | 19 +++++++++++
> net/lwip/Makefile | 2 ++
> net/lwip/apps/dns/lwip-dns.c | 63 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 84 insertions(+)
> create mode 100644 include/net/lwip.h
> create mode 100644 net/lwip/apps/dns/lwip-dns.c
>
> diff --git a/include/net/lwip.h b/include/net/lwip.h
> new file mode 100644
> index 0000000000..ab3db1a214
> --- /dev/null
> +++ b/include/net/lwip.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +int do_lwip_dns(struct cmd_tbl *cmdtp, int flag, int argc,
> + char *const argv[]);
> +
> +/**
> + * ulwip_dns() - creates the DNS request to resolve a domain host name
> + *
> + * This function creates the DNS request to resolve a domain host name.
> Function
> + * can return immediately if previous request was cached or it might require
> + * entering the polling loop for a request to a remote server.
> + *
> + * @name: dns name to resolve
> + * @varname: (optional) U-Boot variable name to store the result
> + * Returns: ERR_OK(0) for fetching entry from the cache
> + * -EINPROGRESS success, can go to the polling loop
> + * Other value < 0, if error
> + */
> +int ulwip_dns(char *name, char *varname);
> diff --git a/net/lwip/Makefile b/net/lwip/Makefile
> index 3fd5d34564..5d8d5527c6 100644
> --- a/net/lwip/Makefile
> +++ b/net/lwip/Makefile
> @@ -62,3 +62,5 @@ obj-$(CONFIG_NET) += lwip-external/src/netif/ethernet.o
>
> obj-$(CONFIG_NET) += port/if.o
> obj-$(CONFIG_NET) += port/sys-arch.o
> +
> +obj-y += apps/dns/lwip-dns.o
> diff --git a/net/lwip/apps/dns/lwip-dns.c b/net/lwip/apps/dns/lwip-dns.c
> new file mode 100644
> index 0000000000..b340302f2c
> --- /dev/null
> +++ b/net/lwip/apps/dns/lwip-dns.c
> @@ -0,0 +1,63 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * (C) Copyright 2023 Linaro Ltd. <maxim.uva...@linaro.org>
> + */
> +
> +#include <common.h>
> +#include <command.h>
> +#include <console.h>
> +
> +#include <lwip/dns.h>
> +#include <lwip/ip_addr.h>
> +
> +#include <net/ulwip.h>
> +
> +static void dns_found_cb(const char *name, const ip_addr_t *ipaddr, void
> *callback_arg)
> +{
> + char *varname = (char *)callback_arg;
> + char *ipstr = ip4addr_ntoa(ipaddr);
> +
> + if (varname)
> + env_set(varname, ipstr);
> + log_info("resolved %s to %s\n", name, ipstr);
> + ulwip_exit(0);
> +}
> +
> +int ulwip_dns(char *name, char *varname)
> +{
> + int err;
> + ip_addr_t ipaddr; /* not used */
> + ip_addr_t dns1;
> + ip_addr_t dns2;
> + char *dnsenv = env_get("dnsip");
> + char *dns2env = env_get("dnsip2");
> +
> + if (!dnsenv && !dns2env) {
> + log_err("nameserver is not set with dnsip and dnsip2 vars\n");
> + return -ENOENT;
> + }
> +
> + if (!dnsenv)
> + log_warning("dnsip var is not set\n");
> + if (!dns2env)
> + log_warning("dnsip2 var is not set\n");
> +
> + dns_init();
> +
> + if (ipaddr_aton(dnsenv, &dns1))
> + dns_setserver(0, &dns1);
> +
> + if (ipaddr_aton(dns2env, &dns2))
> + dns_setserver(1, &dns2);
env_get will return NULL if any of these is not set. Looking at
ipaddr_aton() of lwip that might lead to a NULL deref in ip_2_ip6()
> +
> + err = dns_gethostbyname(name, &ipaddr, dns_found_cb, varname);
> + if (err == ERR_OK)
> + dns_found_cb(name, &ipaddr, varname);
> +
> + /* convert lwIP ERR_INPROGRESS to U-Boot -EINPROGRESS */
> + if (err == ERR_INPROGRESS)
> + err = -EINPROGRESS;
> +
> + return err;
> +}
> --
> 2.30.2
>
