![Eric Dumazet](/assets/img/avatar_default.png)
This patch makes gre_handle_offloads() more generic and rename it to iptunnel_handle_offloads() This will be used to add GSO/TSO support to IPIP tunnels. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
386 lines
8.5 KiB
C
386 lines
8.5 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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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/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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static struct gre_cisco_protocol __rcu *gre_cisco_proto_list[GRE_IP_PROTO_MAX];
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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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void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
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int hdr_len)
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{
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struct gre_base_hdr *greh;
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skb_push(skb, hdr_len);
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greh = (struct gre_base_hdr *)skb->data;
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greh->flags = tnl_flags_to_gre_flags(tpi->flags);
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greh->protocol = tpi->proto;
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if (tpi->flags&(TUNNEL_KEY|TUNNEL_CSUM|TUNNEL_SEQ)) {
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__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
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if (tpi->flags&TUNNEL_SEQ) {
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*ptr = tpi->seq;
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ptr--;
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}
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if (tpi->flags&TUNNEL_KEY) {
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*ptr = tpi->key;
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ptr--;
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}
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if (tpi->flags&TUNNEL_CSUM &&
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!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE)) {
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*ptr = 0;
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*(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
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skb->len, 0));
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}
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}
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}
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EXPORT_SYMBOL_GPL(gre_build_header);
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static __sum16 check_checksum(struct sk_buff *skb)
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{
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__sum16 csum = 0;
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switch (skb->ip_summed) {
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case CHECKSUM_COMPLETE:
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csum = csum_fold(skb->csum);
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if (!csum)
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break;
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/* Fall through. */
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case CHECKSUM_NONE:
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skb->csum = 0;
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csum = __skb_checksum_complete(skb);
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skb->ip_summed = CHECKSUM_COMPLETE;
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break;
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}
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return csum;
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}
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static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
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bool *csum_err)
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{
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unsigned int ip_hlen = ip_hdrlen(skb);
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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, sizeof(struct gre_base_hdr))))
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return -EINVAL;
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greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
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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 = ip_gre_calc_hlen(tpi->flags);
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if (!pskb_may_pull(skb, hdr_len))
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return -EINVAL;
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greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
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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 (check_checksum(skb)) {
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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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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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/* WCCP version 1 and 2 protocol decoding.
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* - Change protocol to IP
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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 = htons(ETH_P_IP);
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if ((*(u8 *)options & 0xF0) != 0x40) {
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hdr_len += 4;
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if (!pskb_may_pull(skb, hdr_len))
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return -EINVAL;
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}
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}
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return iptunnel_pull_header(skb, hdr_len, tpi->proto);
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}
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static int gre_cisco_rcv(struct sk_buff *skb)
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{
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struct tnl_ptk_info tpi;
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int i;
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bool csum_err = false;
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if (parse_gre_header(skb, &tpi, &csum_err) < 0)
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goto drop;
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rcu_read_lock();
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for (i = 0; i < GRE_IP_PROTO_MAX; i++) {
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struct gre_cisco_protocol *proto;
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int ret;
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proto = rcu_dereference(gre_cisco_proto_list[i]);
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if (!proto)
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continue;
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ret = proto->handler(skb, &tpi);
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if (ret == PACKET_RCVD) {
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rcu_read_unlock();
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return 0;
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}
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}
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rcu_read_unlock();
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icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
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drop:
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kfree_skb(skb);
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return 0;
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}
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static void gre_cisco_err(struct sk_buff *skb, u32 info)
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{
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/* All the routers (except for Linux) return only
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* 8 bytes of packet payload. It means, that precise relaying of
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* ICMP in the real Internet is absolutely infeasible.
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*
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* Moreover, Cisco "wise men" put GRE key to the third word
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* in GRE header. It makes impossible maintaining even soft
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* state for keyed
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* GRE tunnels with enabled checksum. Tell them "thank you".
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*
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* Well, I wonder, rfc1812 was written by Cisco employee,
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* what the hell these idiots break standards established
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* by themselves???
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*/
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const int type = icmp_hdr(skb)->type;
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const int code = icmp_hdr(skb)->code;
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struct tnl_ptk_info tpi;
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bool csum_err = false;
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int i;
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if (parse_gre_header(skb, &tpi, &csum_err)) {
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if (!csum_err) /* ignore csum errors. */
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return;
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}
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if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
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ipv4_update_pmtu(skb, dev_net(skb->dev), info,
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skb->dev->ifindex, 0, IPPROTO_GRE, 0);
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return;
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}
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if (type == ICMP_REDIRECT) {
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ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0,
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IPPROTO_GRE, 0);
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return;
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}
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rcu_read_lock();
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for (i = 0; i < GRE_IP_PROTO_MAX; i++) {
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struct gre_cisco_protocol *proto;
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proto = rcu_dereference(gre_cisco_proto_list[i]);
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if (!proto)
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continue;
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if (proto->err_handler(skb, info, &tpi) == PACKET_RCVD)
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goto out;
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}
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out:
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rcu_read_unlock();
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}
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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 void 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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if (ver >= GREPROTO_MAX)
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return;
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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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rcu_read_unlock();
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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 const struct gre_protocol ipgre_protocol = {
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.handler = gre_cisco_rcv,
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.err_handler = gre_cisco_err,
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};
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int gre_cisco_register(struct gre_cisco_protocol *newp)
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{
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struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **)
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&gre_cisco_proto_list[newp->priority];
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return (cmpxchg(proto, NULL, newp) == NULL) ? 0 : -EBUSY;
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}
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EXPORT_SYMBOL_GPL(gre_cisco_register);
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int gre_cisco_unregister(struct gre_cisco_protocol *del_proto)
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{
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struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **)
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&gre_cisco_proto_list[del_proto->priority];
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int ret;
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ret = (cmpxchg(proto, del_proto, NULL) == del_proto) ? 0 : -EINVAL;
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if (ret)
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return ret;
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synchronize_net();
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return 0;
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}
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EXPORT_SYMBOL_GPL(gre_cisco_unregister);
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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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goto err;
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}
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if (gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0) {
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pr_info("%s: can't add ipgre handler\n", __func__);
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goto err_gre;
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}
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if (gre_offload_init()) {
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pr_err("can't add protocol offload\n");
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goto err_gso;
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}
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return 0;
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err_gso:
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gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
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err_gre:
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inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
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err:
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return -EAGAIN;
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}
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static void __exit gre_exit(void)
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{
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gre_offload_exit();
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gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
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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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