[LEDE-DEV] [PATCH odhcpd] Support muliple RAs on single interface

Hans Dedecker dedeckeh at gmail.com
Fri Dec 8 05:09:25 PST 2017


On Fri, Dec 8, 2017 at 10:33 AM,  <ppfister at cisco.com> wrote:
> From: Pierre Pfister <ppfister at cisco.com>
>
> IETF is moving toward implementing IPv6 multihoming by sending
> multiple RAs on a single interface:
> - draft-ietf-intarea-provisioning-domains-00
> - draft-ietf-rtgwg-enterprise-pa-multihoming-02
>
> odhcpd supports configuration of multiple software interfaces
> on the same physical interface, which already advertises
> multiple RAs, but had two issues:
> - Each RA includes all the prefixes available on the interface.
> - Replies to sollicits with a single RA.
>
> This patch introduces the prefix_filter configuration parameter
> which allows filtering prefixes that are sent in a given RA,
> and fixes the sollicit code in order to reply with all the RAs
> that are configured on a given interface.
>
> Signed-off-by: Pierre Pfister <ppfister at cisco.com>
> ---
>  src/config.c | 19 +++++++++++++++++++
>  src/odhcpd.c | 28 +++++++++++++++++++---------
>  src/odhcpd.h |  2 ++
>  src/router.c |  5 +++++
>  4 files changed, 45 insertions(+), 9 deletions(-)
>
> diff --git a/src/config.c b/src/config.c
> index bb885d0..409b3b8 100644
> --- a/src/config.c
> +++ b/src/config.c
> @@ -62,6 +62,7 @@ enum {
>         IFACE_ATTR_PD_CER,
>         IFACE_ATTR_NDPROXY_ROUTING,
>         IFACE_ATTR_NDPROXY_SLAVE,
> +       IFACE_ATTR_PREFIX_FILTER,
>         IFACE_ATTR_MAX
>  };
>
> @@ -104,6 +105,7 @@ static const struct blobmsg_policy iface_attrs[IFACE_ATTR_MAX] = {
>         [IFACE_ATTR_RA_MTU] = { .name = "ra_mtu", .type = BLOBMSG_TYPE_INT32 },
>         [IFACE_ATTR_NDPROXY_ROUTING] = { .name = "ndproxy_routing", .type = BLOBMSG_TYPE_BOOL },
>         [IFACE_ATTR_NDPROXY_SLAVE] = { .name = "ndproxy_slave", .type = BLOBMSG_TYPE_BOOL },
> +       [IFACE_ATTR_PREFIX_FILTER] = { .name = "prefix_filter", .type = BLOBMSG_TYPE_STRING },
>  };
>
>  static const struct uci_blob_param_info iface_attr_info[IFACE_ATTR_MAX] = {
> @@ -720,6 +722,23 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr
>         if ((c = tb[IFACE_ATTR_NDPROXY_SLAVE]))
>                 iface->external = blobmsg_get_bool(c);
>
> +       if ((c = tb[IFACE_ATTR_PREFIX_FILTER])) {
> +               const char *str = blobmsg_get_string(c);
> +               char *astr = malloc(strlen(str) + 1);
> +               char *delim;
> +               int l;
> +               if (!astr || !strcpy(astr, str) ||
> +                               (delim = strchr(astr, '/')) == NULL || (*(delim++) = 0) ||
> +                               sscanf(delim, "%i", &l) == 0 || l > 128 ||
> +                               inet_pton(AF_INET6, astr, &iface->pio_filter_addr) == 0) {
> +                       iface->pio_filter_length = 0;
> +               } else {
> +                       iface->pio_filter_length = l;
> +               }
> +               if (astr)
> +                       free(astr);
> +       }
> +
>         return 0;
>
>  err:
> diff --git a/src/odhcpd.c b/src/odhcpd.c
> index 97a6de9..58c4338 100644
> --- a/src/odhcpd.c
> +++ b/src/odhcpd.c
> @@ -371,12 +371,6 @@ static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int even
>                 if (addr.ll.sll_family == AF_PACKET)
>                         destiface = addr.ll.sll_ifindex;
>
> -               struct interface *iface =
> -                               odhcpd_get_interface_by_index(destiface);
> -
> -               if (!iface && addr.nl.nl_family != AF_NETLINK)
> -                       continue;
> -
>                 char ipbuf[INET6_ADDRSTRLEN] = "kernel";
>                 if (addr.ll.sll_family == AF_PACKET &&
>                                 len >= (ssize_t)sizeof(struct ip6_hdr))
> @@ -386,10 +380,26 @@ static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int even
>                 else if (addr.in.sin_family == AF_INET)
>                         inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
>
> -               syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
> -                               ipbuf, (iface) ? iface->ifname : "netlink");
> +               // From netlink
> +               if (addr.nl.nl_family == AF_NETLINK) {
> +                       syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
> +                                       ipbuf, "netlink");
> +                       e->handle_dgram(&addr, data_buf, len, NULL, dest);
> +                       return;
> +               } else if (destiface != 0) {
> +                       struct interface *iface;
> +                       list_for_each_entry(iface, &interfaces, head) {
> +                               if (iface->ifindex != destiface)
> +                                       continue;
> +
> +                               syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
> +                                               ipbuf, iface->ifname);
> +
> +                               e->handle_dgram(&addr, data_buf, len, iface, dest);
> +                       }
> +               }
> +
>
> -               e->handle_dgram(&addr, data_buf, len, iface, dest);
>         }
>  }
>
> diff --git a/src/odhcpd.h b/src/odhcpd.h
> index fbfeb67..48ee51e 100644
> --- a/src/odhcpd.h
> +++ b/src/odhcpd.h
> @@ -208,6 +208,8 @@ struct interface {
>         bool ra_advrouter;
>         bool ra_useleasetime;
>         bool no_dynamic_dhcp;
> +       uint8_t pio_filter_length;
> +       struct in6_addr pio_filter_addr;
>
>         // RA
>         int learn_routes;
> diff --git a/src/router.c b/src/router.c
> index c35cd12..7bc94ed 100644
> --- a/src/router.c
> +++ b/src/router.c
> @@ -380,6 +380,11 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
>                         continue;
>                 }
>
> +               if (odhcpd_bmemcmp(&addr->addr, &iface->pio_filter_addr,
> +                               iface->pio_filter_length) != 0 ||
> +                               addr->prefix < iface->pio_filter_length)
> +                       continue; // PIO filtered out of this RA
> +
>                 struct nd_opt_prefix_info *p = NULL;
>                 for (size_t i = 0; i < pfxs_cnt; ++i) {
>                         if (addr->prefix == pfxs[i].nd_opt_pi_prefix_len &&
> --
> 2.13.6 (Apple Git-96)
>
>
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Hi,

Thx for the patch; could you also document the prefix_filter uci
parameter in the README file ?

 Hans



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