projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 00959ade DK |
1 | /* |
| 2 | * GRE over IPv4 demultiplexer driver | |
| 3 | * | |
| 4 | * Authors: Dmitry Kozlov ([email protected]) | |
| 5 | * | |
| 6 | * This program is free software; you can redistribute it and/or | |
| 7 | * modify it under the terms of the GNU General Public License | |
| 8 | * as published by the Free Software Foundation; either version | |
| 9 | * 2 of the License, or (at your option) any later version. | |
| 10 | * | |
| 11 | */ | |
| 12 | ||
| 13 | #include <linux/module.h> | |
| 14 | #include <linux/kernel.h> | |
| 15 | #include <linux/kmod.h> | |
| 16 | #include <linux/skbuff.h> | |
| 17 | #include <linux/in.h> | |
| 559fafb9 | 18 | #include <linux/ip.h> |
| 00959ade | 19 | #include <linux/netdevice.h> |
| 00959ade DK |
20 | #include <linux/spinlock.h> |
| 21 | #include <net/protocol.h> | |
| 22 | #include <net/gre.h> | |
| 23 | ||
| 24 | ||
| 6f0bcf15 | 25 | static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly; |
| 00959ade DK |
26 | static DEFINE_SPINLOCK(gre_proto_lock); |
| 27 | ||
| 28 | int gre_add_protocol(const struct gre_protocol *proto, u8 version) | |
| 29 | { | |
| 30 | if (version >= GREPROTO_MAX) | |
| 31 | goto err_out; | |
| 32 | ||
| 33 | spin_lock(&gre_proto_lock); | |
| 34 | if (gre_proto[version]) | |
| 35 | goto err_out_unlock; | |
| 36 | ||
| 37 | rcu_assign_pointer(gre_proto[version], proto); | |
| 38 | spin_unlock(&gre_proto_lock); | |
| 39 | return 0; | |
| 40 | ||
| 41 | err_out_unlock: | |
| 42 | spin_unlock(&gre_proto_lock); | |
| 43 | err_out: | |
| 44 | return -1; | |
| 45 | } | |
| 46 | EXPORT_SYMBOL_GPL(gre_add_protocol); | |
| 47 | ||
| 48 | int gre_del_protocol(const struct gre_protocol *proto, u8 version) | |
| 49 | { | |
| 50 | if (version >= GREPROTO_MAX) | |
| 51 | goto err_out; | |
| 52 | ||
| 53 | spin_lock(&gre_proto_lock); | |
| 6f0bcf15 ED |
54 | if (rcu_dereference_protected(gre_proto[version], |
| 55 | lockdep_is_held(&gre_proto_lock)) != proto) | |
| 00959ade DK |
56 | goto err_out_unlock; |
| 57 | rcu_assign_pointer(gre_proto[version], NULL); | |
| 58 | spin_unlock(&gre_proto_lock); | |
| 59 | synchronize_rcu(); | |
| 60 | return 0; | |
| 61 | ||
| 62 | err_out_unlock: | |
| 63 | spin_unlock(&gre_proto_lock); | |
| 64 | err_out: | |
| 65 | return -1; | |
| 66 | } | |
| 67 | EXPORT_SYMBOL_GPL(gre_del_protocol); | |
| 68 | ||
| 69 | static int gre_rcv(struct sk_buff *skb) | |
| 70 | { | |
| 71 | const struct gre_protocol *proto; | |
| 72 | u8 ver; | |
| 73 | int ret; | |
| 74 | ||
| 75 | if (!pskb_may_pull(skb, 12)) | |
| 76 | goto drop; | |
| 77 | ||
| 78 | ver = skb->data[1]&0x7f; | |
| 79 | if (ver >= GREPROTO_MAX) | |
| 80 | goto drop; | |
| 81 | ||
| 82 | rcu_read_lock(); | |
| 83 | proto = rcu_dereference(gre_proto[ver]); | |
| 84 | if (!proto || !proto->handler) | |
| 85 | goto drop_unlock; | |
| 86 | ret = proto->handler(skb); | |
| 87 | rcu_read_unlock(); | |
| 88 | return ret; | |
| 89 | ||
| 90 | drop_unlock: | |
| 91 | rcu_read_unlock(); | |
| 92 | drop: | |
| 93 | kfree_skb(skb); | |
| 94 | return NET_RX_DROP; | |
| 95 | } | |
| 96 | ||
| 97 | static void gre_err(struct sk_buff *skb, u32 info) | |
| 98 | { | |
| 99 | const struct gre_protocol *proto; | |
| 559fafb9 | 100 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
| 101 | u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f; | |
| 00959ade | 102 | |
| 00959ade | 103 | if (ver >= GREPROTO_MAX) |
| 559fafb9 | 104 | return; |
| 00959ade DK |
105 | |
| 106 | rcu_read_lock(); | |
| 107 | proto = rcu_dereference(gre_proto[ver]); | |
| 559fafb9 | 108 | if (proto && proto->err_handler) |
| 109 | proto->err_handler(skb, info); | |
| 00959ade | 110 | rcu_read_unlock(); |
| 00959ade DK |
111 | } |
| 112 | ||
| 113 | static const struct net_protocol net_gre_protocol = { | |
| 114 | .handler = gre_rcv, | |
| 115 | .err_handler = gre_err, | |
| 116 | .netns_ok = 1, | |
| 117 | }; | |
| 118 | ||
| 119 | static int __init gre_init(void) | |
| 120 | { | |
| 121 | pr_info("GRE over IPv4 demultiplexor driver"); | |
| 122 | ||
| 123 | if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) { | |
| 124 | pr_err("gre: can't add protocol\n"); | |
| 125 | return -EAGAIN; | |
| 126 | } | |
| 127 | ||
| 128 | return 0; | |
| 129 | } | |
| 130 | ||
| 131 | static void __exit gre_exit(void) | |
| 132 | { | |
| 133 | inet_del_protocol(&net_gre_protocol, IPPROTO_GRE); | |
| 134 | } | |
| 135 | ||
| 136 | module_init(gre_init); | |
| 137 | module_exit(gre_exit); | |
| 138 | ||
| 139 | MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver"); | |
| 140 | MODULE_AUTHOR("D. Kozlov ([email protected])"); | |
| 141 | MODULE_LICENSE("GPL"); | |
| 142 |