diff options
Diffstat (limited to 'net/ipv4/gre.c')
| -rw-r--r-- | net/ipv4/gre.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/net/ipv4/gre.c b/net/ipv4/gre.c new file mode 100644 index 000000000000..c6933f2ea310 --- /dev/null +++ b/net/ipv4/gre.c @@ -0,0 +1,152 @@ +/* + * GRE over IPv4 demultiplexer driver + * + * Authors: Dmitry Kozlov (xeb@mail.ru) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/kmod.h> +#include <linux/skbuff.h> +#include <linux/in.h> +#include <linux/netdevice.h> +#include <linux/version.h> +#include <linux/spinlock.h> +#include <net/protocol.h> +#include <net/gre.h> + + +static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly; +static DEFINE_SPINLOCK(gre_proto_lock); + +int gre_add_protocol(const struct gre_protocol *proto, u8 version) +{ + if (version >= GREPROTO_MAX) + goto err_out; + + spin_lock(&gre_proto_lock); + if (gre_proto[version]) + goto err_out_unlock; + + rcu_assign_pointer(gre_proto[version], proto); + spin_unlock(&gre_proto_lock); + return 0; + +err_out_unlock: + spin_unlock(&gre_proto_lock); +err_out: + return -1; +} +EXPORT_SYMBOL_GPL(gre_add_protocol); + +int gre_del_protocol(const struct gre_protocol *proto, u8 version) +{ + if (version >= GREPROTO_MAX) + goto err_out; + + spin_lock(&gre_proto_lock); + if (rcu_dereference_protected(gre_proto[version], + lockdep_is_held(&gre_proto_lock)) != proto) + goto err_out_unlock; + rcu_assign_pointer(gre_proto[version], NULL); + spin_unlock(&gre_proto_lock); + synchronize_rcu(); + return 0; + +err_out_unlock: + spin_unlock(&gre_proto_lock); +err_out: + return -1; +} +EXPORT_SYMBOL_GPL(gre_del_protocol); + +static int gre_rcv(struct sk_buff *skb) +{ + const struct gre_protocol *proto; + u8 ver; + int ret; + + if (!pskb_may_pull(skb, 12)) + goto drop; + + ver = skb->data[1]&0x7f; + if (ver >= GREPROTO_MAX) + goto drop; + + rcu_read_lock(); + proto = rcu_dereference(gre_proto[ver]); + if (!proto || !proto->handler) + goto drop_unlock; + ret = proto->handler(skb); + rcu_read_unlock(); + return ret; + +drop_unlock: + rcu_read_unlock(); +drop: + kfree_skb(skb); + return NET_RX_DROP; +} + +static void gre_err(struct sk_buff *skb, u32 info) +{ + const struct gre_protocol *proto; + u8 ver; + + if (!pskb_may_pull(skb, 12)) + goto drop; + + ver = skb->data[1]&0x7f; + if (ver >= GREPROTO_MAX) + goto drop; + + rcu_read_lock(); + proto = rcu_dereference(gre_proto[ver]); + if (!proto || !proto->err_handler) + goto drop_unlock; + proto->err_handler(skb, info); + rcu_read_unlock(); + return; + +drop_unlock: + rcu_read_unlock(); +drop: + kfree_skb(skb); +} + +static const struct net_protocol net_gre_protocol = { + .handler = gre_rcv, + .err_handler = gre_err, + .netns_ok = 1, +}; + +static int __init gre_init(void) +{ + pr_info("GRE over IPv4 demultiplexor driver"); + + if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) { + pr_err("gre: can't add protocol\n"); + return -EAGAIN; + } + + return 0; +} + +static void __exit gre_exit(void) +{ + inet_del_protocol(&net_gre_protocol, IPPROTO_GRE); +} + +module_init(gre_init); +module_exit(gre_exit); + +MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver"); +MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)"); +MODULE_LICENSE("GPL"); + |