int gre_cisco_register(struct gre_cisco_protocol *proto);
int gre_cisco_unregister(struct gre_cisco_protocol *proto);
+
+int gre_offload_init(void);
+void gre_offload_exit(void);
+
void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
int hdr_len);
struct sk_buff *gre_handle_offloads(struct sk_buff *skb, bool gre_csum);
obj-$(CONFIG_IP_MULTIPLE_TABLES) += fib_rules.o
obj-$(CONFIG_IP_MROUTE) += ipmr.o
obj-$(CONFIG_NET_IPIP) += ipip.o
+gre-y := gre_demux.o gre_offload.o
obj-$(CONFIG_NET_IPGRE_DEMUX) += gre.o
obj-$(CONFIG_NET_IPGRE) += ip_gre.o
obj-$(CONFIG_NET_IPVTI) += ip_vti.o
+++ /dev/null
-/*
- * 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.
- *
- */
-
-#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 <linux/in.h>
-#include <linux/ip.h>
-#include <linux/netdevice.h>
-#include <linux/if_tunnel.h>
-#include <linux/spinlock.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)
-{
- if (version >= GREPROTO_MAX)
- return -EINVAL;
-
- return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
- 0 : -EBUSY;
-}
-EXPORT_SYMBOL_GPL(gre_add_protocol);
-
-int gre_del_protocol(const struct gre_protocol *proto, u8 version)
-{
- int ret;
-
- if (version >= GREPROTO_MAX)
- return -EINVAL;
-
- ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
- 0 : -EBUSY;
-
- if (ret)
- return ret;
-
- synchronize_rcu();
- return 0;
-}
-EXPORT_SYMBOL_GPL(gre_del_protocol);
-
-void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
- int hdr_len)
-{
- struct gre_base_hdr *greh;
-
- skb_push(skb, hdr_len);
-
- greh = (struct gre_base_hdr *)skb->data;
- greh->flags = tnl_flags_to_gre_flags(tpi->flags);
- greh->protocol = tpi->proto;
-
- if (tpi->flags&(TUNNEL_KEY|TUNNEL_CSUM|TUNNEL_SEQ)) {
- __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
-
- if (tpi->flags&TUNNEL_SEQ) {
- *ptr = tpi->seq;
- ptr--;
- }
- if (tpi->flags&TUNNEL_KEY) {
- *ptr = tpi->key;
- ptr--;
- }
- if (tpi->flags&TUNNEL_CSUM &&
- !(skb_shinfo(skb)->gso_type & SKB_GSO_GRE)) {
- *ptr = 0;
- *(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
- skb->len, 0));
- }
- }
-}
-EXPORT_SYMBOL_GPL(gre_build_header);
-
-struct sk_buff *gre_handle_offloads(struct sk_buff *skb, bool gre_csum)
-{
- int err;
-
- if (likely(!skb->encapsulation)) {
- skb_reset_inner_headers(skb);
- skb->encapsulation = 1;
- }
-
- if (skb_is_gso(skb)) {
- err = skb_unclone(skb, GFP_ATOMIC);
- if (unlikely(err))
- goto error;
- skb_shinfo(skb)->gso_type |= SKB_GSO_GRE;
- return skb;
- } else if (skb->ip_summed == CHECKSUM_PARTIAL && gre_csum) {
- err = skb_checksum_help(skb);
- if (unlikely(err))
- goto error;
- } else if (skb->ip_summed != CHECKSUM_PARTIAL)
- skb->ip_summed = CHECKSUM_NONE;
-
- return skb;
-error:
- kfree_skb(skb);
- return ERR_PTR(err);
-}
-EXPORT_SYMBOL_GPL(gre_handle_offloads);
-
-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 iptunnel_pull_header(skb, hdr_len, tpi->proto);
-}
-
-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;
- 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;
- const struct iphdr *iph = (const struct iphdr *)skb->data;
- u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
-
- if (ver >= GREPROTO_MAX)
- return;
-
- rcu_read_lock();
- proto = rcu_dereference(gre_proto[ver]);
- if (proto && proto->err_handler)
- proto->err_handler(skb, info);
- rcu_read_unlock();
-}
-
-static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
- netdev_features_t features)
-{
- struct sk_buff *segs = ERR_PTR(-EINVAL);
- netdev_features_t enc_features;
- int ghl = GRE_HEADER_SECTION;
- struct gre_base_hdr *greh;
- int mac_len = skb->mac_len;
- __be16 protocol = skb->protocol;
- int tnl_hlen;
- bool csum;
-
- if (unlikely(skb_shinfo(skb)->gso_type &
- ~(SKB_GSO_TCPV4 |
- SKB_GSO_TCPV6 |
- SKB_GSO_UDP |
- SKB_GSO_DODGY |
- SKB_GSO_TCP_ECN |
- SKB_GSO_GRE)))
- goto out;
-
- if (unlikely(!pskb_may_pull(skb, sizeof(*greh))))
- goto out;
-
- greh = (struct gre_base_hdr *)skb_transport_header(skb);
-
- if (greh->flags & GRE_KEY)
- ghl += GRE_HEADER_SECTION;
- if (greh->flags & GRE_SEQ)
- ghl += GRE_HEADER_SECTION;
- if (greh->flags & GRE_CSUM) {
- ghl += GRE_HEADER_SECTION;
- csum = true;
- } else
- csum = false;
-
- /* setup inner skb. */
- skb->protocol = greh->protocol;
- skb->encapsulation = 0;
-
- if (unlikely(!pskb_may_pull(skb, ghl)))
- goto out;
- __skb_pull(skb, ghl);
- skb_reset_mac_header(skb);
- skb_set_network_header(skb, skb_inner_network_offset(skb));
- skb->mac_len = skb_inner_network_offset(skb);
-
- /* segment inner packet. */
- enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
- segs = skb_mac_gso_segment(skb, enc_features);
- if (!segs || IS_ERR(segs))
- goto out;
-
- skb = segs;
- tnl_hlen = skb_tnl_header_len(skb);
- do {
- __skb_push(skb, ghl);
- if (csum) {
- __be32 *pcsum;
-
- if (skb_has_shared_frag(skb)) {
- int err;
-
- err = __skb_linearize(skb);
- if (err) {
- kfree_skb(segs);
- segs = ERR_PTR(err);
- goto out;
- }
- }
-
- greh = (struct gre_base_hdr *)(skb->data);
- pcsum = (__be32 *)(greh + 1);
- *pcsum = 0;
- *(__sum16 *)pcsum = csum_fold(skb_checksum(skb, 0, skb->len, 0));
- }
- __skb_push(skb, tnl_hlen - ghl);
-
- skb_reset_mac_header(skb);
- skb_set_network_header(skb, mac_len);
- skb->mac_len = mac_len;
- skb->protocol = protocol;
- } while ((skb = skb->next));
-out:
- return segs;
-}
-
-static int gre_gso_send_check(struct sk_buff *skb)
-{
- if (!skb->encapsulation)
- return -EINVAL;
- return 0;
-}
-
-static const struct net_protocol net_gre_protocol = {
- .handler = gre_rcv,
- .err_handler = gre_err,
- .netns_ok = 1,
-};
-
-static const struct net_offload gre_offload = {
- .callbacks = {
- .gso_send_check = gre_gso_send_check,
- .gso_segment = gre_gso_segment,
- },
-};
-
-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");
- 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");
- 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_init(gre_init);
-module_exit(gre_exit);
-
-MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver");
-MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
-MODULE_LICENSE("GPL");
--- /dev/null
+/*
+ * 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.
+ *
+ */
+
+#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 <linux/in.h>
+#include <linux/ip.h>
+#include <linux/netdevice.h>
+#include <linux/if_tunnel.h>
+#include <linux/spinlock.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)
+{
+ if (version >= GREPROTO_MAX)
+ return -EINVAL;
+
+ return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
+ 0 : -EBUSY;
+}
+EXPORT_SYMBOL_GPL(gre_add_protocol);
+
+int gre_del_protocol(const struct gre_protocol *proto, u8 version)
+{
+ int ret;
+
+ if (version >= GREPROTO_MAX)
+ return -EINVAL;
+
+ ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
+ 0 : -EBUSY;
+
+ if (ret)
+ return ret;
+
+ synchronize_rcu();
+ return 0;
+}
+EXPORT_SYMBOL_GPL(gre_del_protocol);
+
+void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
+ int hdr_len)
+{
+ struct gre_base_hdr *greh;
+
+ skb_push(skb, hdr_len);
+
+ greh = (struct gre_base_hdr *)skb->data;
+ greh->flags = tnl_flags_to_gre_flags(tpi->flags);
+ greh->protocol = tpi->proto;
+
+ if (tpi->flags&(TUNNEL_KEY|TUNNEL_CSUM|TUNNEL_SEQ)) {
+ __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
+
+ if (tpi->flags&TUNNEL_SEQ) {
+ *ptr = tpi->seq;
+ ptr--;
+ }
+ if (tpi->flags&TUNNEL_KEY) {
+ *ptr = tpi->key;
+ ptr--;
+ }
+ if (tpi->flags&TUNNEL_CSUM &&
+ !(skb_shinfo(skb)->gso_type & SKB_GSO_GRE)) {
+ *ptr = 0;
+ *(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
+ skb->len, 0));
+ }
+ }
+}
+EXPORT_SYMBOL_GPL(gre_build_header);
+
+struct sk_buff *gre_handle_offloads(struct sk_buff *skb, bool gre_csum)
+{
+ int err;
+
+ if (likely(!skb->encapsulation)) {
+ skb_reset_inner_headers(skb);
+ skb->encapsulation = 1;
+ }
+
+ if (skb_is_gso(skb)) {
+ err = skb_unclone(skb, GFP_ATOMIC);
+ if (unlikely(err))
+ goto error;
+ skb_shinfo(skb)->gso_type |= SKB_GSO_GRE;
+ return skb;
+ } else if (skb->ip_summed == CHECKSUM_PARTIAL && gre_csum) {
+ err = skb_checksum_help(skb);
+ if (unlikely(err))
+ goto error;
+ } else if (skb->ip_summed != CHECKSUM_PARTIAL)
+ skb->ip_summed = CHECKSUM_NONE;
+
+ return skb;
+error:
+ kfree_skb(skb);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(gre_handle_offloads);
+
+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 iptunnel_pull_header(skb, hdr_len, tpi->proto);
+}
+
+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;
+ 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;
+ const struct iphdr *iph = (const struct iphdr *)skb->data;
+ u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
+
+ if (ver >= GREPROTO_MAX)
+ return;
+
+ rcu_read_lock();
+ proto = rcu_dereference(gre_proto[ver]);
+ if (proto && proto->err_handler)
+ proto->err_handler(skb, info);
+ rcu_read_unlock();
+}
+
+static const struct net_protocol net_gre_protocol = {
+ .handler = gre_rcv,
+ .err_handler = gre_err,
+ .netns_ok = 1,
+};
+
+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");
+ 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 (gre_offload_init()) {
+ pr_err("can't add protocol offload\n");
+ 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)
+{
+ gre_offload_exit();
+
+ gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
+ 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");
--- /dev/null
+/*
+ * IPV4 GSO/GRO offload support
+ * Linux INET implementation
+ *
+ * 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.
+ *
+ * GRE GSO support
+ */
+
+#include <linux/skbuff.h>
+#include <net/protocol.h>
+#include <net/gre.h>
+
+static int gre_gso_send_check(struct sk_buff *skb)
+{
+ if (!skb->encapsulation)
+ return -EINVAL;
+ return 0;
+}
+
+static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
+ netdev_features_t features)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ netdev_features_t enc_features;
+ int ghl = GRE_HEADER_SECTION;
+ struct gre_base_hdr *greh;
+ int mac_len = skb->mac_len;
+ __be16 protocol = skb->protocol;
+ int tnl_hlen;
+ bool csum;
+
+ if (unlikely(skb_shinfo(skb)->gso_type &
+ ~(SKB_GSO_TCPV4 |
+ SKB_GSO_TCPV6 |
+ SKB_GSO_UDP |
+ SKB_GSO_DODGY |
+ SKB_GSO_TCP_ECN |
+ SKB_GSO_GRE)))
+ goto out;
+
+ if (unlikely(!pskb_may_pull(skb, sizeof(*greh))))
+ goto out;
+
+ greh = (struct gre_base_hdr *)skb_transport_header(skb);
+
+ if (greh->flags & GRE_KEY)
+ ghl += GRE_HEADER_SECTION;
+ if (greh->flags & GRE_SEQ)
+ ghl += GRE_HEADER_SECTION;
+ if (greh->flags & GRE_CSUM) {
+ ghl += GRE_HEADER_SECTION;
+ csum = true;
+ } else
+ csum = false;
+
+ /* setup inner skb. */
+ skb->protocol = greh->protocol;
+ skb->encapsulation = 0;
+
+ if (unlikely(!pskb_may_pull(skb, ghl)))
+ goto out;
+
+ __skb_pull(skb, ghl);
+ skb_reset_mac_header(skb);
+ skb_set_network_header(skb, skb_inner_network_offset(skb));
+ skb->mac_len = skb_inner_network_offset(skb);
+
+ /* segment inner packet. */
+ enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
+ segs = skb_mac_gso_segment(skb, enc_features);
+ if (!segs || IS_ERR(segs))
+ goto out;
+
+ skb = segs;
+ tnl_hlen = skb_tnl_header_len(skb);
+ do {
+ __skb_push(skb, ghl);
+ if (csum) {
+ __be32 *pcsum;
+
+ if (skb_has_shared_frag(skb)) {
+ int err;
+
+ err = __skb_linearize(skb);
+ if (err) {
+ kfree_skb(segs);
+ segs = ERR_PTR(err);
+ goto out;
+ }
+ }
+
+ greh = (struct gre_base_hdr *)(skb->data);
+ pcsum = (__be32 *)(greh + 1);
+ *pcsum = 0;
+ *(__sum16 *)pcsum = csum_fold(skb_checksum(skb, 0, skb->len, 0));
+ }
+ __skb_push(skb, tnl_hlen - ghl);
+
+ skb_reset_mac_header(skb);
+ skb_set_network_header(skb, mac_len);
+ skb->mac_len = mac_len;
+ skb->protocol = protocol;
+ } while ((skb = skb->next));
+out:
+ return segs;
+}
+
+static const struct net_offload gre_offload = {
+ .callbacks = {
+ .gso_send_check = gre_gso_send_check,
+ .gso_segment = gre_gso_segment,
+ },
+};
+
+int __init gre_offload_init(void)
+{
+ return inet_add_offload(&gre_offload, IPPROTO_GRE);
+}
+
+void __exit gre_offload_exit(void)
+{
+ inet_del_offload(&gre_offload, IPPROTO_GRE);
+}
projects / cascardo / linux.git / commitdiff