答复: [Patch] udhcpc6: support generate a consistent iaid

[zhousiqi (A)]

Gentle ping...
Please check if the community accepts this submission.

> -----邮件原件-----
> 发件人: zhousiqi (A)
> 发送时间: 2024年4月12日 15:09
> 收件人: busybox at busybox.net
> 主题: [Patch] udhcpc6: support generate a consistent iaid
> 
> Currently, udhcpc6 does not meet the requirements for Identity Association in
> RFC 3315.
> This is a specific explanation of RFC 3315 protocol:
> https://datatracker.ietf.org/doc/html/rfc3315#section-10
> “The IAID uniquely identifies the IA and must be chosen to be unique
>    among the IAIDs on the client.  The IAID is chosen by the client.
>    For any given use of an IA by the client, the IAID for that IA MUST
>    be consistent across restarts of the DHCP client.”
> This patch allows the client to generate a consistent IAID based on the MAC
> address.
> 
> Signed-off-by: Zhou Siqi <zhousiqi5 at huawei.com>
> ---
>  networking/udhcp/d6_dhcpc.c | 30 ++++++++++++++++++++++++++++--
>  1 file changed, 28 insertions(+), 2 deletions(-)
> 
> diff --git a/networking/udhcp/d6_dhcpc.c b/networking/udhcp/d6_dhcpc.c
> index a35488d..99a53c8 100644
> --- a/networking/udhcp/d6_dhcpc.c
> +++ b/networking/udhcp/d6_dhcpc.c
> @@ -741,6 +741,32 @@ static NOINLINE int send_d6_info_request(void)
>        |     OPTION_RECONF_ACCEPT      |               0
> |
>        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>   */
> +
> +/*obtain a consistent IAID based on the MAC address*/ static int
> +d6_create_iaid() {
> +       int data = 0;
> +       int start_idx = 0, copy_len = 0;
> +       int mac_len = 0;
> +
> +       mac_len = sizeof(client_data.client_mac);
> +
> +       /*
> +        * A simple IAID is the last 4 bytes
> +        * of the hardware address.
> +        */
> +       if (mac_len > 4) {
> +               start_idx = mac_len - 4;
> +               copy_len = 4;
> +       } else {
> +               copy_len = mac_len;
> +       }
> +
> +       memcpy(&data, &client_data.client_mac[start_idx], copy_len);
> +
> +       return data;
> +}
> +
>  /* NOINLINE: limit stack usage in caller */  static NOINLINE int
> send_d6_discover(struct in6_addr *requested_ipv6)  { @@ -759,7 +785,7 @@
> static NOINLINE int send_d6_discover(struct in6_addr *requested_ipv6)
>                  client6_data.ia_na = xzalloc(len);
>                  client6_data.ia_na->code = D6_OPT_IA_NA;
>                  client6_data.ia_na->len = len - 4;
> -               *(bb__aliased_uint32_t*)client6_data.ia_na->data = rand();
> /* IAID */
> +               *(bb__aliased_uint32_t*)client6_data.ia_na->data =
> + d6_create_iaid(); /* IAID */
>                  if (requested_ipv6) {
>                          struct d6_option *iaaddr =
> (void*)(client6_data.ia_na->data + 4+4+4);
>                          iaaddr->code = D6_OPT_IAADDR; @@ -777,7
> +803,7 @@ static NOINLINE int send_d6_discover(struct in6_addr
> *requested_ipv6)
>                  client6_data.ia_pd = xzalloc(len);
>                  client6_data.ia_pd->code = D6_OPT_IA_PD;
>                  client6_data.ia_pd->len = len - 4;
> -               *(bb__aliased_uint32_t*)client6_data.ia_pd->data = rand();
> /* IAID */
> +               *(bb__aliased_uint32_t*)client6_data.ia_pd->data =
> + d6_create_iaid(); /* IAID */
>                  opt_ptr = mempcpy(opt_ptr, client6_data.ia_pd, len);
>          }