Re: [PATCH] send router solicitation for ipv6 address autoconf

[Andrei Borzenkov <arvidjaar@gmail.com>]

В Thu, 13 Nov 2014 17:42:23 +0800
Michael Chang <mchang@suse.com> пишет:

> Many routers have long router advertisment interval configured by
> default. The Neighbor Discovery protocol (RFC4861) has defined default
> MaxRtrAdvInterval value as 600 seconds and
> MinRtrAdvInterval as 0.33*MaxRtrAdvInterval. This makes
> net_ipv6_autoconf fails more often than not as currently it passively
> listens the RA message to perfom address autoconfiguration.
> 
> This patch tries to send router solicitation to overcome the problem of
> long RA interval.
> ---
>  grub-core/net/icmp6.c |   81 +++++++++++++++++++++++++++++++++++++++++++++++++
>  grub-core/net/net.c   |    4 ++-
>  include/grub/net/ip.h |    2 +
>  3 files changed, 86 insertions(+), 1 deletions(-)
> 
> diff --git a/grub-core/net/icmp6.c b/grub-core/net/icmp6.c
> index 796d549..87b264f 100644
> --- a/grub-core/net/icmp6.c
> +++ b/grub-core/net/icmp6.c
> @@ -72,6 +72,11 @@ struct neighbour_advertise
>    grub_uint64_t target[2];
>  } GRUB_PACKED;
>  
> +struct router_solicit
> +{
> +  grub_uint32_t reserved;
> +} GRUB_PACKED;
> +
>  enum
>    {
>      FLAG_SLAAC = 0x40
> @@ -81,6 +86,7 @@ enum
>    {
>      ICMP6_ECHO = 128,
>      ICMP6_ECHO_REPLY = 129,
> +    ICMP6_ROUTER_SOLICIT = 133,
>      ICMP6_ROUTER_ADVERTISE = 134,
>      ICMP6_NEIGHBOUR_SOLICIT = 135,
>      ICMP6_NEIGHBOUR_ADVERTISE = 136,
> @@ -533,3 +539,78 @@ grub_net_icmp6_send_request (struct grub_net_network_level_interface *inf,
>    grub_netbuff_free (nb);
>    return err;
>  }
> +
> +grub_err_t
> +grub_net_icmp6_send_router_solicit (struct grub_net_network_level_interface *inf)
> +{
> +  struct grub_net_buff *nb;
> +  grub_err_t err = GRUB_ERR_NONE;
> +  grub_net_network_level_address_t multicast;
> +  grub_net_link_level_address_t ll_multicast;
> +  struct option_header *ohdr;
> +  struct router_solicit *sol;
> +  struct icmp_header *icmphr;
> +
> +  multicast.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV6;
> +  multicast.ipv6[0] = grub_be_to_cpu64_compile_time (0xff02ULL << 48);
> +  multicast.ipv6[1] = grub_be_to_cpu64_compile_time (0x02ULL);
> +

Could you use cpu_to_be variant; it makes it less confusing (that is
what we do here).

> +  err = grub_net_link_layer_resolve (inf, &multicast, &ll_multicast);
> +  if (err)
> +    return err;
> +
> +  nb = grub_netbuff_alloc (sizeof (struct router_solicit)
> +			   + sizeof (struct option_header)
> +			   + 6
> +			   + sizeof (struct icmp_header)
> +			   + GRUB_NET_OUR_IPV6_HEADER_SIZE
> +			   + GRUB_NET_MAX_LINK_HEADER_SIZE);
> +  if (!nb)
> +    return grub_errno;
> +  err = grub_netbuff_reserve (nb,
> +			      sizeof (struct router_solicit)
> +			      + sizeof (struct option_header)
> +			      + 6
> +			      + sizeof (struct icmp_header)
> +			      + GRUB_NET_OUR_IPV6_HEADER_SIZE
> +			      + GRUB_NET_MAX_LINK_HEADER_SIZE);
> +

Error check?

Otherwise personally I'm fine with it.

> +  err = grub_netbuff_push (nb, 6);
> +  if (err)
> +    goto fail;
> +
> +  grub_memcpy (nb->data, inf->hwaddress.mac, 6);
> +
> +  err = grub_netbuff_push (nb, sizeof (*ohdr));
> +  if (err)
> +    goto fail;
> +
> +  ohdr = (struct option_header *) nb->data;
> +  ohdr->type = OPTION_SOURCE_LINK_LAYER_ADDRESS;
> +  ohdr->len = 1;
> +
> +  err = grub_netbuff_push (nb, sizeof (*sol));  
> +  if (err)
> +    goto fail;
> +
> +  sol = (struct router_solicit *) nb->data;
> +  sol->reserved = 0;
> +
> +  err = grub_netbuff_push (nb, sizeof (*icmphr));
> +  if (err)
> +    goto fail;
> +
> +  icmphr = (struct icmp_header *) nb->data;
> +  icmphr->type = ICMP6_ROUTER_SOLICIT;
> +  icmphr->code = 0;
> +  icmphr->checksum = 0;
> +  icmphr->checksum = grub_net_ip_transport_checksum (nb,
> +						     GRUB_NET_IP_ICMPV6,
> +						     &inf->address,
> +						     &multicast);
> +  err = grub_net_send_ip_packet (inf, &multicast, &ll_multicast, nb,
> +				 GRUB_NET_IP_ICMPV6);
> + fail:
> +  grub_netbuff_free (nb);
> +  return err;
> +}
> diff --git a/grub-core/net/net.c b/grub-core/net/net.c
> index 82af3a0..21a4e94 100644
> --- a/grub-core/net/net.c
> +++ b/grub-core/net/net.c
> @@ -380,12 +380,14 @@ grub_cmd_ipv6_autoconf (struct grub_command *cmd __attribute__ ((unused)),
>  
>    for (interval = 200; interval < 10000; interval *= 2)
>      {
> -      /* FIXME: send router solicitation.  */
>        int done = 1;
>        for (j = 0; j < ncards; j++)
>  	{
>  	  if (slaacs[j]->slaac_counter)
>  	    continue;
> +	  err = grub_net_icmp6_send_router_solicit (ifaces[j]);
> +	  if (err)
> +	    err = GRUB_ERR_NONE;
>  	  done = 0;
>  	}
>        if (done)
> diff --git a/include/grub/net/ip.h b/include/grub/net/ip.h
> index 7a8e614..dcceaa5 100644
> --- a/include/grub/net/ip.h
> +++ b/include/grub/net/ip.h
> @@ -92,4 +92,6 @@ grub_err_t
>  grub_net_icmp6_send_request (struct grub_net_network_level_interface *inf,
>  			     const grub_net_network_level_address_t *proto_addr);
>  
> +grub_err_t
> +grub_net_icmp6_send_router_solicit (struct grub_net_network_level_interface *inf);
>  #endif