Hi,
On 08/04/2016 03:09 PM, Alexander Aring wrote:
> This patch adds a mechanism to get the device address length via
> netlink. This is necessary for device type 6LoWPAN which can have
> different device address lengths.
> ---
> device-linux.c | 16 +++++++++++++--
> netlink.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> netlink.h | 1 +
> 3 files changed, 79 insertions(+), 2 deletions(-)
>
> diff --git a/device-linux.c b/device-linux.c
> index 7301927..1ccb207 100644
> --- a/device-linux.c
> +++ b/device-linux.c
> @@ -17,6 +17,7 @@
> #include "radvd.h"
> #include "defaults.h"
> #include "pathnames.h"
> +#include "netlink.h"
>
> #ifndef IPV6_ADDR_LINKLOCAL
> #define IPV6_ADDR_LINKLOCAL 0x0020U
> @@ -84,8 +85,19 @@ int update_device_info(int sock, struct Interface *iface)
> break;
> #endif /* ARPHDR_ARCNET */
> case ARPHRD_6LOWPAN:
> - iface->sllao.if_hwaddr_len = 64;
> - iface->sllao.if_prefix_len = 64;
> +#ifdef HAVE_NETLINK
> + /* hwaddr length differs on some L2 type lets detect them */
> + iface->sllao.if_hwaddr_len = netlink_get_device_addr_len(iface);
> + if (iface->sllao.if_hwaddr_len != -1) {
> + iface->sllao.if_hwaddr_len *= 8;
> + iface->sllao.if_prefix_len = 64;
> + } else {
> + iface->sllao.if_prefix_len = -1;
> + }
> +#else
> + iface->sllao.if_hwaddr_len = -1;
> + iface->sllao.if_prefix_len = -1;
> +#endif
> break;
> default:
> iface->sllao.if_hwaddr_len = -1;
> diff --git a/netlink.c b/netlink.c
> index 80d2254..d07a0b8 100644
> --- a/netlink.c
> +++ b/netlink.c
> @@ -32,6 +32,70 @@
> #define SOL_NETLINK 270
> #endif
>
> +struct iplink_req {
> + struct nlmsghdr n;
> + struct ifinfomsg i;
> + char buf[1024];
> +};
> +
> +int netlink_get_device_addr_len(struct Interface *iface)
> +{
> + struct iplink_req req = {};
> + struct iovec iov = { &req, sizeof(req) };
> + struct sockaddr_nl sa = {};
> + struct msghdr msg = { (void *)&sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
> + int sock, len, addr_len = -1;
> + unsigned short type;
> + char answer[32768];
> + struct rtattr *tb;
> +
> + /* nl_pid (for linux kernel) and nl_groups (unicast) should be zero */
> + sa.nl_family = AF_NETLINK;
> + req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
> + req.n.nlmsg_flags = NLM_F_REQUEST;
> + req.n.nlmsg_type = RTM_GETLINK;
> + req.i.ifi_index = iface->props.if_index;
> +
> + sock = netlink_socket();
> + if (sock == -1)
> + return -1;
> +
> + len = sendmsg(sock, &msg, 0);
> + if (len == -1) {
> + flog(LOG_ERR, "netlink: sendmsg for addr_len failed: %s", strerror(errno));
> + close(sock);
need to be removed.
> + goto out;
> + }
> +
> + iov.iov_base = answer;
> + iov.iov_len = sizeof(answer);
> + len = recvmsg(sock, &msg, 0);
> + if (len == -1) {
> + flog(LOG_ERR, "netlink: recvmsg for addr_len failed: %s", strerror(errno));
> + close(sock);
same here.
> + goto out;
> + }
> +
> + if (len < NLMSG_LENGTH(sizeof(struct ifinfomsg)))
> + goto out;
> + len -= NLMSG_LENGTH(sizeof(struct ifinfomsg));
> +
> + tb = (struct rtattr *)(answer + NLMSG_LENGTH(sizeof(struct ifinfomsg)));
> + while (RTA_OK(tb, len)) {
> + type = tb->rta_type & ~NLA_F_NESTED;
> + if (type == IFLA_ADDRESS) {
> + addr_len = RTA_PAYLOAD(tb);
> + break;
> + }
> + tb = RTA_NEXT(tb, len);
> + }
> +
> +out:
> + close(sock);
will be done here.
I will fix that before sending the pull-request if everything else is
fine enough. :-)
- Alex
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