Re: [lwip-devel] [PATCHv4 5/5] net/lwip: apps/http: add dns support

[Ilias Apalodimas]

On Fri, Jul 14, 2023 at 08:20:00PM +0600, Maxim Uvarov wrote:
> provide hostname to client and allow lwip to resolve it.
> 
> Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
> ---
>  lib/lwip/apps/http/lwip-wget.c | 59 ++++++++++++++++++++++++++++++----
>  1 file changed, 53 insertions(+), 6 deletions(-)
> 
> diff --git a/lib/lwip/apps/http/lwip-wget.c b/lib/lwip/apps/http/lwip-wget.c
> index 0308b0b04a..db553a0f14 100644
> --- a/lib/lwip/apps/http/lwip-wget.c
> +++ b/lib/lwip/apps/http/lwip-wget.c
> @@ -45,18 +45,65 @@ static void httpc_result(void *arg, httpc_result_t 
> httpc_result, u32_t rx_conten
>       }
>  }
>  
> +/* http://hostname:port/url */
> +static int parse_url(char *url, char *host, int *port)
> +{
> +     int ret;
> +     char *p, *pp;
> +
> +     p = strstr(url, "http://";);
> +     if (!p) {
> +             printf("err: no http://!\n";);
> +             return -1;
> +     }
> +
> +     p += strlen("http://";);
> +
> +     /* parse hostname */
> +     pp = strchr(p, ':');
> +     if (pp) {
> +             char portstr[5];
> +
> +             memcpy(host, p, pp - p);

You are copying bytes over without taking into account the length of the
array. Also, I think we should keep things as simple as possible for the
first iteration, so can we ignore the port config for now and just stick to
80?

Thanks
/Ilias
> +             host[pp - p + 1] = '\0';
> +
> +             p = pp + 1;
> +             pp = strchr(p, '/');
> +             if (!pp) {
> +                     printf("wrong url\n");
> +                     return -2;
> +             }
> +
> +             memcpy(portstr, p, pp - p);
> +             portstr[pp - p] = '\0';
> +             *port = atoi(portstr);
> +     } else {
> +             pp = strchr(p, '/');
> +             if (!pp) {
> +                     printf("wrong url\n");
> +                     return -3;
> +             }
> +             memcpy(host, p, pp - p);
> +             host[pp - p + 1] = '\0';
> +             *port = 80; /* default */
> +     }
> +
> +     return 0;
> +}
> +
>  int lwip_wget(ulong addr, char *url)
>  {
>       err_t err;
> -     int port = 80;
> -     char *server_name;
> +     int port;
> +     char server_name[80];
>       httpc_state_t *connection;
>  
>       daddr = addr;
> -     server_name = env_get("serverip");
> -     if (!server_name) {
> -             printf("error: serverip variable has to be set\n");
> -             return CMD_RET_FAILURE;
> +
> +     err = parse_url(url, server_name, &port);
> +     if (err) {
> +             printf("error parse_url\n");
> +             return -1;
>       }
>  
>       printf("downloading %s to addr 0x%lx\n", url, addr);
> -- 
> 2.30.2
>