[PATCH] libertas: Per-socket mesh-ttl via setsockopt().

[Dan Williams]

On Mon, 2007-07-09 at 13:12 -0700, Javier Cardona wrote:
> Support for using setsockpt() to change the mesh-ttl on a network flow, i.e.
> 
> <snip>
>     sock = socket (PF_INET, SOCK_STREAM, 0);
>     setsockopt(sock, SOL_IP, MESH_SO_SET_TTL, &ttl, optlen);
>     ttl = 0;
>     getsockopt(sock, SOL_IP, MESH_SO_GET_TTL, &ttl, &optlen);
> </snip>

Hmm; how does this fit in with the libertas driver?  And where is
MESH_SO_SET_TTL defined?

Dan

> Signed-off-by: Javier Cardona <javier at cozybit.com>
> ---
>  drivers/net/wireless/libertas/mesh_opts.c |  174 +++++++++++++++++++++++++++++
>  drivers/net/wireless/libertas/mesh_opts.h |    5 +
>  2 files changed, 179 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/net/wireless/libertas/mesh_opts.c b/drivers/net/wireless/libertas/mesh_opts.c
> new file mode 100644
> index 0000000..118eaed
> --- /dev/null
> +++ b/drivers/net/wireless/libertas/mesh_opts.c
> @@ -0,0 +1,174 @@
> +/*
> + * mesh_opts
> + *
> + * Author: Javier Cardona <javier at cozybit.com>
> + * Copyright: Marvell Semiconductors Inc., 2007
> + *
> + * Apply mesh-layer specific configuration to network flows.  Currently this
> + * only supports the mesh TTL parameter.
> + *
> + * Users call setsockopt on sockets to configure mesh parameters.  This module
> + * maintains a list of sockets (mesh_sks) that have different mesh parameters
> + * than the per-interface defaults.  The driver will modify the mesh
> + * configuration for each outgoing frame that belongs to one of the sockets in
> + * the mesh_sks list.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/list.h>
> +#include <linux/net.h>
> +#include <linux/in.h>
> +#include <linux/netfilter.h>
> +#include <linux/netfilter_ipv4.h>
> +#include <linux/netfilter_ipv6.h>
> +#include <linux/spinlock.h>
> +#include <net/sock.h>
> +
> +#include <asm/uaccess.h>
> +
> +#include "mesh_opts.h"
> +
> +#define MESH_SO_BASE_CTL 	MESH_SO_SET_TTL
> +
> +static struct list_head mesh_sks = LIST_HEAD_INIT(mesh_sks);
> +static DEFINE_RWLOCK(mesh_sks_lock);
> +
> +struct mesh_sock {
> +	struct list_head list;
> +
> +	struct sock *sk;
> +	unsigned char ttl;
> +	void (*orig_sk_destruct) (struct sock *sk);
> +};
> +
> +static struct mesh_sock * lookup_socket(struct sock *sk)
> +{
> +	struct mesh_sock *mesh_sk;
> +	struct mesh_sock *found_sk = NULL;
> +
> +	read_lock(&mesh_sks_lock);
> +	list_for_each_entry(mesh_sk, &mesh_sks, list) 
> +		if (mesh_sk->sk == sk) {
> +			found_sk = mesh_sk;
> +			break;
> +		}
> +	read_unlock(&mesh_sks_lock);
> +	return found_sk;
> +}
> +
> +static void mesh_sk_destruct(struct sock *sk)
> +{
> +	struct mesh_sock *mesh_sk;
> +	void (*orig_sk_destruct) (struct sock *sk);
> +
> +	mesh_sk = lookup_socket(sk);
> +
> +	if (mesh_sk) {
> +		orig_sk_destruct = mesh_sk->orig_sk_destruct;
> +		write_lock(&mesh_sks_lock);
> +		list_del(&mesh_sk->list);
> +		write_unlock(&mesh_sks_lock);
> +		kfree(mesh_sk);
> +		(*orig_sk_destruct)(sk);
> +	}
> +}
> +
> +static int do_mesh_set_mesh_ttl(struct sock *sk, void __user *user, unsigned int len)
> +{
> +	struct mesh_sock *mesh_sk;
> +	unsigned char ttl;
> +
> +
> +	if (len) {
> +		if (get_user(ttl, (unsigned char *) user))
> +			return -EFAULT;
> +	} else
> +		return -EINVAL;
> +
> +	mesh_sk = (struct mesh_sock*) kmalloc(sizeof(struct mesh_sock), GFP_KERNEL);
> +	mesh_sk->ttl = ttl;
> +	mesh_sk->sk = sk;
> +	mesh_sk->orig_sk_destruct = sk->sk_destruct;
> +	sk->sk_destruct = mesh_sk_destruct;
> +	write_lock(&mesh_sks_lock);
> +	list_add(&mesh_sk->list, &mesh_sks);
> +	write_unlock(&mesh_sks_lock);
> +
> +	return 0;
> +}
> +
> +static int do_mesh_get_mesh_ttl(struct sock *sk, void __user *user, int *len)
> +{
> +	struct mesh_sock *mesh_sk;
> +	int rc = 0;
> +
> +	if ((mesh_sk = lookup_socket(sk)) == NULL)
> +		return -ENODATA;	
> +
> +	if (put_user(mesh_sk->ttl, (unsigned char*) user))
> +		return -EFAULT;
> +
> +	/* netfilter wrapper does the copy to user of len */
> +	*len = sizeof(unsigned char);
> +
> +	return rc;
> +}
> +
> +static int do_mesh_set_ctl(struct sock *sk, int optval, void __user *user,
> +		unsigned int len) 
> +{
> +	return do_mesh_set_mesh_ttl(sk, user, len);
> +}
> +
> +static int do_mesh_get_ctl(struct sock *sk, int optval, void __user *user, 
> +		int *len) 
> +{
> +	return do_mesh_get_mesh_ttl(sk, user, len);
> +}
> +
> +static unsigned char get_sock_mesh_ttl(struct sock *sk)
> +{
> +	struct mesh_sock *mesh_sk;
> +
> +	mesh_sk = lookup_socket(sk);
> +
> +	/* zero ttl results in using the network interface default */
> +	return mesh_sk ? mesh_sk->ttl : 0;	
> +}
> +
> +static struct mesh_options mesh_opts =
> +{
> +	.get_sock_ttl = get_sock_mesh_ttl,
> +};
> +
> +static struct nf_sockopt_ops mesh_sockopt_ops =
> +{
> +	.pf		= PF_INET,
> +	.set_optmin     = MESH_SO_BASE_CTL,
> +	.set_optmax     = MESH_SO_BASE_CTL + 1,
> +	.set		= do_mesh_set_ctl,
> +	.get_optmin     = MESH_SO_BASE_CTL,
> +	.get_optmax     = MESH_SO_BASE_CTL + 1,
> +	.get		= do_mesh_get_ctl,
> +};
> +
> +static int __init mesh_opts_init(void)
> +{
> +	int ret;
> +
> +	if ((ret = nf_register_sockopt(&mesh_sockopt_ops)) < 0) {
> +		return ret;
> +	}
> +	libertas_register_mesh_opts(&mesh_opts);
> +	return ret;
> +}
> +
> +static void __exit mesh_opts_fini(void)
> +{
> +	nf_unregister_sockopt(&mesh_sockopt_ops);
> +	libertas_unregister_mesh_opts(&mesh_opts);
> +}
> +
> +module_init(mesh_opts_init);
> +module_exit(mesh_opts_fini);
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/net/wireless/libertas/mesh_opts.h b/drivers/net/wireless/libertas/mesh_opts.h
> new file mode 100644
> index 0000000..cd18fb1
> --- /dev/null
> +++ b/drivers/net/wireless/libertas/mesh_opts.h
> @@ -0,0 +1,5 @@
> +
> +struct mesh_options {
> +	unsigned char (*get_sock_ttl)(struct sock*);
> +};
> +