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Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
214 lines
4.6 KiB
C
214 lines
4.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* GRE over IPv4 demultiplexer driver
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*
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* Authors: Dmitry Kozlov (xeb@mail.ru)
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/if.h>
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#include <linux/icmp.h>
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#include <linux/kernel.h>
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#include <linux/kmod.h>
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#include <linux/skbuff.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/netdevice.h>
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#include <linux/if_tunnel.h>
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#include <linux/spinlock.h>
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#include <net/protocol.h>
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#include <net/gre.h>
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#include <net/erspan.h>
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#include <net/icmp.h>
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#include <net/route.h>
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#include <net/xfrm.h>
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static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
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int gre_add_protocol(const struct gre_protocol *proto, u8 version)
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{
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if (version >= GREPROTO_MAX)
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return -EINVAL;
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return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
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0 : -EBUSY;
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}
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EXPORT_SYMBOL_GPL(gre_add_protocol);
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int gre_del_protocol(const struct gre_protocol *proto, u8 version)
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{
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int ret;
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if (version >= GREPROTO_MAX)
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return -EINVAL;
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ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
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0 : -EBUSY;
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if (ret)
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return ret;
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synchronize_rcu();
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return 0;
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}
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EXPORT_SYMBOL_GPL(gre_del_protocol);
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/* Fills in tpi and returns header length to be pulled. */
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int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
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bool *csum_err, __be16 proto, int nhs)
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{
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const struct gre_base_hdr *greh;
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__be32 *options;
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int hdr_len;
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if (unlikely(!pskb_may_pull(skb, nhs + sizeof(struct gre_base_hdr))))
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return -EINVAL;
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greh = (struct gre_base_hdr *)(skb->data + nhs);
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if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
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return -EINVAL;
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tpi->flags = gre_flags_to_tnl_flags(greh->flags);
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hdr_len = gre_calc_hlen(tpi->flags);
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if (!pskb_may_pull(skb, nhs + hdr_len))
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return -EINVAL;
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greh = (struct gre_base_hdr *)(skb->data + nhs);
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tpi->proto = greh->protocol;
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options = (__be32 *)(greh + 1);
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if (greh->flags & GRE_CSUM) {
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if (!skb_checksum_simple_validate(skb)) {
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skb_checksum_try_convert(skb, IPPROTO_GRE, 0,
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null_compute_pseudo);
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} else if (csum_err) {
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*csum_err = true;
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return -EINVAL;
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}
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options++;
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}
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if (greh->flags & GRE_KEY) {
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tpi->key = *options;
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options++;
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} else {
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tpi->key = 0;
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}
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if (unlikely(greh->flags & GRE_SEQ)) {
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tpi->seq = *options;
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options++;
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} else {
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tpi->seq = 0;
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}
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/* WCCP version 1 and 2 protocol decoding.
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* - Change protocol to IPv4/IPv6
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* - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
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*/
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if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
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tpi->proto = proto;
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if ((*(u8 *)options & 0xF0) != 0x40)
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hdr_len += 4;
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}
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tpi->hdr_len = hdr_len;
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/* ERSPAN ver 1 and 2 protocol sets GRE key field
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* to 0 and sets the configured key in the
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* inner erspan header field
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*/
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if (greh->protocol == htons(ETH_P_ERSPAN) ||
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greh->protocol == htons(ETH_P_ERSPAN2)) {
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struct erspan_base_hdr *ershdr;
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if (!pskb_may_pull(skb, nhs + hdr_len + sizeof(*ershdr)))
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return -EINVAL;
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ershdr = (struct erspan_base_hdr *)options;
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tpi->key = cpu_to_be32(get_session_id(ershdr));
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}
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return hdr_len;
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}
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EXPORT_SYMBOL(gre_parse_header);
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static int gre_rcv(struct sk_buff *skb)
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{
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const struct gre_protocol *proto;
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u8 ver;
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int ret;
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if (!pskb_may_pull(skb, 12))
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goto drop;
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ver = skb->data[1]&0x7f;
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if (ver >= GREPROTO_MAX)
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goto drop;
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rcu_read_lock();
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proto = rcu_dereference(gre_proto[ver]);
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if (!proto || !proto->handler)
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goto drop_unlock;
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ret = proto->handler(skb);
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rcu_read_unlock();
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return ret;
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drop_unlock:
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rcu_read_unlock();
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drop:
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kfree_skb(skb);
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return NET_RX_DROP;
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}
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static int gre_err(struct sk_buff *skb, u32 info)
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{
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const struct gre_protocol *proto;
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const struct iphdr *iph = (const struct iphdr *)skb->data;
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u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
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int err = 0;
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if (ver >= GREPROTO_MAX)
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return -EINVAL;
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rcu_read_lock();
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proto = rcu_dereference(gre_proto[ver]);
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if (proto && proto->err_handler)
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proto->err_handler(skb, info);
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else
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err = -EPROTONOSUPPORT;
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rcu_read_unlock();
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return err;
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}
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static const struct net_protocol net_gre_protocol = {
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.handler = gre_rcv,
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.err_handler = gre_err,
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.netns_ok = 1,
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};
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static int __init gre_init(void)
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{
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pr_info("GRE over IPv4 demultiplexor driver\n");
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if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
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pr_err("can't add protocol\n");
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return -EAGAIN;
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}
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return 0;
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}
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static void __exit gre_exit(void)
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{
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inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
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}
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module_init(gre_init);
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module_exit(gre_exit);
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MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver");
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MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
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MODULE_LICENSE("GPL");
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