#define GREPROTO_CISCO 0
#define GREPROTO_PPTP 1
#define GREPROTO_MAX 2
+#define GRE_IP_PROTO_MAX 2
struct gre_protocol {
int (*handler)(struct sk_buff *skb);
int gre_add_protocol(const struct gre_protocol *proto, u8 version);
int gre_del_protocol(const struct gre_protocol *proto, u8 version);
+struct gre_cisco_protocol {
+ int (*handler)(struct sk_buff *skb, const struct tnl_ptk_info *tpi);
+ int (*err_handler)(struct sk_buff *skb, u32 info,
+ const struct tnl_ptk_info *tpi);
+ u8 priority;
+};
+
+int gre_cisco_register(struct gre_cisco_protocol *proto);
+int gre_cisco_unregister(struct gre_cisco_protocol *proto);
+
+static inline int ip_gre_calc_hlen(__be16 o_flags)
+{
+ int addend = 4;
+
+ if (o_flags&TUNNEL_CSUM)
+ addend += 4;
+ if (o_flags&TUNNEL_KEY)
+ addend += 4;
+ if (o_flags&TUNNEL_SEQ)
+ addend += 4;
+ return addend;
+}
+
static inline __be16 gre_flags_to_tnl_flags(__be16 flags)
{
__be16 tflags = 0;
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
+#include <linux/if.h>
+#include <linux/icmp.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/skbuff.h>
#include <net/protocol.h>
#include <net/gre.h>
+#include <net/icmp.h>
+#include <net/route.h>
+#include <net/xfrm.h>
static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
+static struct gre_cisco_protocol __rcu *gre_cisco_proto_list[GRE_IP_PROTO_MAX];
int gre_add_protocol(const struct gre_protocol *proto, u8 version)
{
}
EXPORT_SYMBOL_GPL(gre_del_protocol);
+static __sum16 check_checksum(struct sk_buff *skb)
+{
+ __sum16 csum = 0;
+
+ switch (skb->ip_summed) {
+ case CHECKSUM_COMPLETE:
+ csum = csum_fold(skb->csum);
+
+ if (!csum)
+ break;
+ /* Fall through. */
+
+ case CHECKSUM_NONE:
+ skb->csum = 0;
+ csum = __skb_checksum_complete(skb);
+ skb->ip_summed = CHECKSUM_COMPLETE;
+ break;
+ }
+
+ return csum;
+}
+
+static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
+ bool *csum_err)
+{
+ unsigned int ip_hlen = ip_hdrlen(skb);
+ const struct gre_base_hdr *greh;
+ __be32 *options;
+ int hdr_len;
+
+ if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
+ return -EINVAL;
+
+ greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
+ if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
+ return -EINVAL;
+
+ tpi->flags = gre_flags_to_tnl_flags(greh->flags);
+ hdr_len = ip_gre_calc_hlen(tpi->flags);
+
+ if (!pskb_may_pull(skb, hdr_len))
+ return -EINVAL;
+
+ greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
+ tpi->proto = greh->protocol;
+
+ options = (__be32 *)(greh + 1);
+ if (greh->flags & GRE_CSUM) {
+ if (check_checksum(skb)) {
+ *csum_err = true;
+ return -EINVAL;
+ }
+ options++;
+ }
+
+ if (greh->flags & GRE_KEY) {
+ tpi->key = *options;
+ options++;
+ } else
+ tpi->key = 0;
+
+ if (unlikely(greh->flags & GRE_SEQ)) {
+ tpi->seq = *options;
+ options++;
+ } else
+ tpi->seq = 0;
+
+ /* WCCP version 1 and 2 protocol decoding.
+ * - Change protocol to IP
+ * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
+ */
+ if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
+ tpi->proto = htons(ETH_P_IP);
+ if ((*(u8 *)options & 0xF0) != 0x40) {
+ hdr_len += 4;
+ if (!pskb_may_pull(skb, hdr_len))
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+static int gre_cisco_rcv(struct sk_buff *skb)
+{
+ struct tnl_ptk_info tpi;
+ int i;
+ bool csum_err = false;
+
+ if (parse_gre_header(skb, &tpi, &csum_err) < 0)
+ goto drop;
+
+ rcu_read_lock();
+ for (i = 0; i < GRE_IP_PROTO_MAX; i++) {
+ struct gre_cisco_protocol *proto;
+ int ret;
+
+ proto = rcu_dereference(gre_cisco_proto_list[i]);
+ if (!proto)
+ continue;
+ ret = proto->handler(skb, &tpi);
+ if (ret == PACKET_RCVD) {
+ rcu_read_unlock();
+ return 0;
+ }
+ }
+ rcu_read_unlock();
+
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
+drop:
+ kfree_skb(skb);
+ return 0;
+}
+
+static void gre_cisco_err(struct sk_buff *skb, u32 info)
+{
+ /* All the routers (except for Linux) return only
+ * 8 bytes of packet payload. It means, that precise relaying of
+ * ICMP in the real Internet is absolutely infeasible.
+ *
+ * Moreover, Cisco "wise men" put GRE key to the third word
+ * in GRE header. It makes impossible maintaining even soft
+ * state for keyed
+ * GRE tunnels with enabled checksum. Tell them "thank you".
+ *
+ * Well, I wonder, rfc1812 was written by Cisco employee,
+ * what the hell these idiots break standards established
+ * by themselves???
+ */
+
+ const int type = icmp_hdr(skb)->type;
+ const int code = icmp_hdr(skb)->code;
+ struct tnl_ptk_info tpi;
+ bool csum_err = false;
+ int i;
+
+ if (parse_gre_header(skb, &tpi, &csum_err)) {
+ if (!csum_err) /* ignore csum errors. */
+ return;
+ }
+
+ if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
+ ipv4_update_pmtu(skb, dev_net(skb->dev), info,
+ skb->dev->ifindex, 0, IPPROTO_GRE, 0);
+ return;
+ }
+ if (type == ICMP_REDIRECT) {
+ ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0,
+ IPPROTO_GRE, 0);
+ return;
+ }
+
+ rcu_read_lock();
+ for (i = 0; i < GRE_IP_PROTO_MAX; i++) {
+ struct gre_cisco_protocol *proto;
+
+ proto = rcu_dereference(gre_cisco_proto_list[i]);
+ if (!proto)
+ continue;
+
+ if (proto->err_handler(skb, info, &tpi) == PACKET_RCVD)
+ goto out;
+
+ }
+out:
+ rcu_read_unlock();
+}
+
static int gre_rcv(struct sk_buff *skb)
{
const struct gre_protocol *proto;
},
};
+static const struct gre_protocol ipgre_protocol = {
+ .handler = gre_cisco_rcv,
+ .err_handler = gre_cisco_err,
+};
+
+int gre_cisco_register(struct gre_cisco_protocol *newp)
+{
+ struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **)
+ &gre_cisco_proto_list[newp->priority];
+
+ return (cmpxchg(proto, NULL, newp) == NULL) ? 0 : -EBUSY;
+}
+EXPORT_SYMBOL_GPL(gre_cisco_register);
+
+int gre_cisco_unregister(struct gre_cisco_protocol *del_proto)
+{
+ struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **)
+ &gre_cisco_proto_list[del_proto->priority];
+ int ret;
+
+ ret = (cmpxchg(proto, del_proto, NULL) == del_proto) ? 0 : -EINVAL;
+
+ if (ret)
+ return ret;
+
+ synchronize_net();
+ return 0;
+}
+EXPORT_SYMBOL_GPL(gre_cisco_unregister);
+
static int __init gre_init(void)
{
pr_info("GRE over IPv4 demultiplexor driver\n");
if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
pr_err("can't add protocol\n");
- return -EAGAIN;
+ goto err;
+ }
+
+ if (gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0) {
+ pr_info("%s: can't add ipgre handler\n", __func__);
+ goto err_gre;
}
if (inet_add_offload(&gre_offload, IPPROTO_GRE)) {
pr_err("can't add protocol offload\n");
- inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
- return -EAGAIN;
+ goto err_gso;
}
return 0;
+err_gso:
+ gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
+err_gre:
+ inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
+err:
+ return -EAGAIN;
}
static void __exit gre_exit(void)
{
inet_del_offload(&gre_offload, IPPROTO_GRE);
+ gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
}
MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver");
MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
MODULE_LICENSE("GPL");
-
static int ipgre_net_id __read_mostly;
static int gre_tap_net_id __read_mostly;
-static __sum16 check_checksum(struct sk_buff *skb)
-{
- __sum16 csum = 0;
-
- switch (skb->ip_summed) {
- case CHECKSUM_COMPLETE:
- csum = csum_fold(skb->csum);
-
- if (!csum)
- break;
- /* Fall through. */
-
- case CHECKSUM_NONE:
- skb->csum = 0;
- csum = __skb_checksum_complete(skb);
- skb->ip_summed = CHECKSUM_COMPLETE;
- break;
- }
-
- return csum;
-}
-
-static int ip_gre_calc_hlen(__be16 o_flags)
-{
- int addend = 4;
-
- if (o_flags&TUNNEL_CSUM)
- addend += 4;
- if (o_flags&TUNNEL_KEY)
- addend += 4;
- if (o_flags&TUNNEL_SEQ)
- addend += 4;
- return addend;
-}
-
-static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
- bool *csum_err, int *hdr_len)
-{
- unsigned int ip_hlen = ip_hdrlen(skb);
- const struct gre_base_hdr *greh;
- __be32 *options;
-
- if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
- return -EINVAL;
-
- greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
- if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
- return -EINVAL;
-
- tpi->flags = gre_flags_to_tnl_flags(greh->flags);
- *hdr_len = ip_gre_calc_hlen(tpi->flags);
-
- if (!pskb_may_pull(skb, *hdr_len))
- return -EINVAL;
-
- greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
-
- tpi->proto = greh->protocol;
-
- options = (__be32 *)(greh + 1);
- if (greh->flags & GRE_CSUM) {
- if (check_checksum(skb)) {
- *csum_err = true;
- return -EINVAL;
- }
- options++;
- }
-
- if (greh->flags & GRE_KEY) {
- tpi->key = *options;
- options++;
- } else
- tpi->key = 0;
-
- if (unlikely(greh->flags & GRE_SEQ)) {
- tpi->seq = *options;
- options++;
- } else
- tpi->seq = 0;
-
- /* WCCP version 1 and 2 protocol decoding.
- * - Change protocol to IP
- * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
- */
- if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
- tpi->proto = htons(ETH_P_IP);
- if ((*(u8 *)options & 0xF0) != 0x40) {
- *hdr_len += 4;
- if (!pskb_may_pull(skb, *hdr_len))
- return -EINVAL;
- }
- }
-
- return 0;
-}
-
-static void ipgre_err(struct sk_buff *skb, u32 info)
+static int ipgre_err(struct sk_buff *skb, u32 info,
+ const struct tnl_ptk_info *tpi)
{
/* All the routers (except for Linux) return only
const int type = icmp_hdr(skb)->type;
const int code = icmp_hdr(skb)->code;
struct ip_tunnel *t;
- struct tnl_ptk_info tpi;
- int hdr_len;
- bool csum_err = false;
-
- if (parse_gre_header(skb, &tpi, &csum_err, &hdr_len)) {
- if (!csum_err) /* ignore csum errors. */
- return;
- }
switch (type) {
default:
case ICMP_PARAMETERPROB:
- return;
+ return PACKET_RCVD;
case ICMP_DEST_UNREACH:
switch (code) {
case ICMP_SR_FAILED:
case ICMP_PORT_UNREACH:
/* Impossible event. */
- return;
+ return PACKET_RCVD;
default:
/* All others are translated to HOST_UNREACH.
rfc2003 contains "deep thoughts" about NET_UNREACH,
break;
case ICMP_TIME_EXCEEDED:
if (code != ICMP_EXC_TTL)
- return;
+ return PACKET_RCVD;
break;
case ICMP_REDIRECT:
break;
}
- if (tpi.proto == htons(ETH_P_TEB))
+ if (tpi->proto == htons(ETH_P_TEB))
itn = net_generic(net, gre_tap_net_id);
else
itn = net_generic(net, ipgre_net_id);
iph = (const struct iphdr *)skb->data;
- t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi.flags,
- iph->daddr, iph->saddr, tpi.key);
+ t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
+ iph->daddr, iph->saddr, tpi->key);
if (t == NULL)
- return;
+ return PACKET_REJECT;
- if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
- ipv4_update_pmtu(skb, dev_net(skb->dev), info,
- t->parms.link, 0, IPPROTO_GRE, 0);
- return;
- }
- if (type == ICMP_REDIRECT) {
- ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
- IPPROTO_GRE, 0);
- return;
- }
if (t->parms.iph.daddr == 0 ||
ipv4_is_multicast(t->parms.iph.daddr))
- return;
+ return PACKET_RCVD;
if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
- return;
+ return PACKET_RCVD;
if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
t->err_count++;
else
t->err_count = 1;
t->err_time = jiffies;
+ return PACKET_RCVD;
}
-static int ipgre_rcv(struct sk_buff *skb)
+static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
{
struct net *net = dev_net(skb->dev);
struct ip_tunnel_net *itn;
const struct iphdr *iph;
struct ip_tunnel *tunnel;
- struct tnl_ptk_info tpi;
- int hdr_len;
- bool csum_err = false;
-
- if (parse_gre_header(skb, &tpi, &csum_err, &hdr_len) < 0)
- goto drop;
- if (tpi.proto == htons(ETH_P_TEB))
+ if (tpi->proto == htons(ETH_P_TEB))
itn = net_generic(net, gre_tap_net_id);
else
itn = net_generic(net, ipgre_net_id);
iph = ip_hdr(skb);
- tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi.flags,
- iph->saddr, iph->daddr, tpi.key);
+ tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
+ iph->saddr, iph->daddr, tpi->key);
if (tunnel) {
- ip_tunnel_rcv(tunnel, skb, &tpi, log_ecn_error);
- return 0;
+ ip_tunnel_rcv(tunnel, skb, tpi, log_ecn_error);
+ return PACKET_RCVD;
}
- icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
-drop:
- kfree_skb(skb);
- return 0;
+ return PACKET_REJECT;
}
static struct sk_buff *handle_offloads(struct ip_tunnel *tunnel, struct sk_buff *skb)
return ip_tunnel_init(dev);
}
-static const struct gre_protocol ipgre_protocol = {
- .handler = ipgre_rcv,
- .err_handler = ipgre_err,
+static struct gre_cisco_protocol ipgre_protocol = {
+ .handler = ipgre_rcv,
+ .err_handler = ipgre_err,
+ .priority = 0,
};
static int __net_init ipgre_init_net(struct net *net)
if (err < 0)
goto pnet_tap_faied;
- err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
+ err = gre_cisco_register(&ipgre_protocol);
if (err < 0) {
pr_info("%s: can't add protocol\n", __func__);
goto add_proto_failed;
tap_ops_failed:
rtnl_link_unregister(&ipgre_link_ops);
rtnl_link_failed:
- gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
+ gre_cisco_unregister(&ipgre_protocol);
add_proto_failed:
unregister_pernet_device(&ipgre_tap_net_ops);
pnet_tap_faied:
{
rtnl_link_unregister(&ipgre_tap_ops);
rtnl_link_unregister(&ipgre_link_ops);
- if (gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0)
- pr_info("%s: can't remove protocol\n", __func__);
+ gre_cisco_unregister(&ipgre_protocol);
unregister_pernet_device(&ipgre_tap_net_ops);
unregister_pernet_device(&ipgre_net_ops);
}
projects / ~andy / linux / commitdiff