[U-Boot] [RFC PATCH v2 06/11] net: IPv6 skeleton and environment variables

Joe Hershberger joe.hershberger at gmail.com
Tue Nov 24 02:06:35 CET 2015


Hi Chris,

On Mon, Nov 9, 2015 at 1:38 AM, Chris Packham <judge.packham at gmail.com> wrote:
> Create net6.c and add CONFIG_NET6 to Kconfig/Makefile. Also add
> support for the following environment variables:
>  - ip6addr
>  - gateway6
>  - serverip6
>
> Signed-off-by: Chris Packham <judge.packham at gmail.com>
> ---
>
> Changes in v2:
> - Split environment variables from main implementation
> - remove "prefixlength6" environment variable. The prefix length is now
>   set when specifying the address i.e. setenv ip6addr 2001:db8::1/64.
>
>  include/env_callback.h |  8 +++++
>  include/env_flags.h    |  9 +++++
>  net/Kconfig            |  5 +++
>  net/Makefile           |  1 +
>  net/net6.c             | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 112 insertions(+)
>  create mode 100644 net/net6.c
>
> diff --git a/include/env_callback.h b/include/env_callback.h
> index 90b95b5..97e245b 100644
> --- a/include/env_callback.h
> +++ b/include/env_callback.h
> @@ -60,6 +60,13 @@
>  #define NET_CALLBACKS
>  #endif
>
> +#ifdef CONFIG_NET6
> +#define NET6_CALLBACKS \
> +       "ip6addr:ip6addr," \
> +       "serverip6:serverip6,"

Any reason why gateway6 is not in this list? Seems like an oversight
since you define a handler for it below.

> +#else
> +#define NET6_CALLBACKS
> +#endif
>  /*
>   * This list of callback bindings is static, but may be overridden by defining
>   * a new association in the ".callbacks" environment variable.
> @@ -68,6 +75,7 @@
>         ENV_DOT_ESCAPE ENV_FLAGS_VAR ":flags," \
>         "baudrate:baudrate," \
>         NET_CALLBACKS \
> +       NET6_CALLBACKS \
>         "loadaddr:loadaddr," \
>         SILENT_CALLBACK \
>         SPLASHIMAGE_CALLBACK \
> diff --git a/include/env_flags.h b/include/env_flags.h
> index 8823fb9..bf93f15 100644
> --- a/include/env_flags.h
> +++ b/include/env_flags.h
> @@ -65,6 +65,14 @@ enum env_flags_varaccess {
>  #define NET_FLAGS
>  #endif
>
> +#ifdef CONFIG_NET6
> +#define NET6_FLAGS \
> +       "ip6addr:s," \
> +       "serverip6:s,"
> +#else
> +#define NET6_FLAGS
> +#endif
> +
>  #ifndef CONFIG_ENV_OVERWRITE
>  #define SERIAL_FLAGS "serial#:so,"
>  #else
> @@ -74,6 +82,7 @@ enum env_flags_varaccess {
>  #define ENV_FLAGS_LIST_STATIC \
>         ETHADDR_FLAGS \
>         NET_FLAGS \
> +       NET6_FLAGS \
>         SERIAL_FLAGS \
>         CONFIG_ENV_FLAGS_LIST_STATIC
>
> diff --git a/net/Kconfig b/net/Kconfig
> index a44a783..bacd914 100644
> --- a/net/Kconfig
> +++ b/net/Kconfig
> @@ -32,4 +32,9 @@ config NET_TFTP_VARS
>           If unset, timeout and maximum are hard-defined as 1 second
>           and 10 timouts per TFTP transfer.
>
> +config NET6
> +       bool "IPv6 support"
> +       help
> +         Support for IPv6
> +
>  endif   # if NET
> diff --git a/net/Makefile b/net/Makefile
> index e9cc8ad..6da8019 100644
> --- a/net/Makefile
> +++ b/net/Makefile
> @@ -20,3 +20,4 @@ obj-$(CONFIG_CMD_PING) += ping.o
>  obj-$(CONFIG_CMD_RARP) += rarp.o
>  obj-$(CONFIG_CMD_SNTP) += sntp.o
>  obj-$(CONFIG_CMD_NET)  += tftp.o
> +obj-$(CONFIG_NET6)     += net6.o
> diff --git a/net/net6.c b/net/net6.c
> new file mode 100644
> index 0000000..f778cef
> --- /dev/null
> +++ b/net/net6.c
> @@ -0,0 +1,89 @@
> +/*
> + * Simple IPv6 network layer implementation.
> + *
> + * Based and/or adapted from the IPv4 network layer in net.[hc]
> + *
> + * (C) Copyright 2013 Allied Telesis Labs NZ
> + *
> + * SPDX-License-Identifier:    GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <environment.h>
> +#include <malloc.h>
> +#include <net.h>
> +#include <net6.h>
> +#include "ndisc.h"
> +
> +/* Our gateway's IPv6 address */
> +struct in6_addr net_gateway6 = ZERO_IPV6_ADDR;
> +/* Our IPv6 addr (0 = unknown) */
> +struct in6_addr net_ip6 = ZERO_IPV6_ADDR;
> +/* set server IPv6 addr (0 = unknown) */
> +struct in6_addr net_server_ip6 = ZERO_IPV6_ADDR;
> +/* The prefix length of our network */
> +u_int32_t net_prefix_length;
> +
> +static int on_ip6addr(const char *name, const char *value, enum env_op op,
> +                     int flags)
> +{
> +       char *v, *s, *strcopy;
> +       int i;
> +
> +       if (flags & H_PROGRAMMATIC)
> +               return 0;
> +
> +       if (op == env_op_delete) {
> +               net_prefix_length = 0;
> +               net_copy_ip6(&net_ip6, &net_null_addr_ip6);
> +               return 0;
> +       }
> +
> +       strcopy = strdup(value);
> +       if (strcopy == NULL)
> +               return -1;

+               return -ENOMEM;

> +
> +       net_prefix_length = 128;

Does this imply that you are allowed to omit this part of the address
now? I assume you are not allowed to omit it, hence the proposed code
below.

> +       i = 0;
> +       s = strcopy;

--------------------
> +       while (s) {
> +               v = strsep(&s, "/");
> +               if (!v)
> +                       break;
> +
> +               switch (i++) {
> +               case 0:
> +                       string_to_ip6(v, &net_ip6);
> +                       break;
> +               case 1:
> +                       net_prefix_length = simple_strtoul(v, NULL, 10);
> +                       break;
> +               default:
> +                       break;
> +               }
> +       }
> +       free(strcopy);
> +
> +       return 0;
> +}
--------------------
This is a bit convoluted.

How about this:
+       int retval = 0;
+
+       if (s) {
+               v = strsep(&s, "/");
+               if (!v) {
+                       retval = -EINVAL;
+                       goto err_out;
+               }
+
+               string_to_ip6(v, &net_ip6);
+
+               v = strsep(&s, "/");
+               if (!v) {
+                       retval = -EINVAL;
+                       goto err_out;
+               }
+
+               net_prefix_length = simple_strtoul(v, NULL, 10);
+       }
+       err_out:
+       free(strcopy);
+
+       return retval;
+}

It is now linear and will return an error code when parsing fails,
which will prevent the variable from being changed.

> +U_BOOT_ENV_CALLBACK(ip6addr, on_ip6addr);
> +
> +static int on_gatewayip6(const char *name, const char *value, enum env_op op,
> +                        int flags)
> +{
> +       if (flags & H_PROGRAMMATIC)
> +               return 0;
> +
> +       return string_to_ip6(value, &net_gateway6);
> +}
> +U_BOOT_ENV_CALLBACK(gatewayip6, on_gatewayip6);
> +
> +static int on_serverip6(const char *name, const char *value, enum env_op op,
> +                       int flags)
> +{
> +       if (flags & H_PROGRAMMATIC)
> +               return 0;
> +
> +       return string_to_ip6(value, &net_server_ip6);
> +}
> +U_BOOT_ENV_CALLBACK(serverip6, on_serverip6);
> --
> 2.5.3
>
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