On 13.09.2023 07:56, Ilias Apalodimas wrote:
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()
Looking at the NULL checks in ipaddr_aton(), you found a bug in lwIP. I'd vote to leave the above code as is and rely on the bug being fixed in lwIP before U-Boot enables IPv6 (this is only a bug in dual-stack mode where IPv4 and IPv6 is enabled). Regards, Simon
+ + 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
