3b26a9a655
IPv4 IPsec tunnel gateway incorrectly sends redirect to sender if it is onlink host when network device the IPsec tunnelled packet is arrived is the same as the one the decapsulated packet is sent. With this patch, it omits to send the redirect when the forwarding skbuff carries secpath, since such skbuff should be assumed as a decapsulated packet from IPsec tunnel by own. Request for comments: Alternatively we'd have another way to change net/ipv4/route.c (__mkroute_input) to use RTCF_DOREDIRECT flag unless skbuff has no secpath. It is better than this patch at performance point of view because IPv4 redirect judgement is done at routing slow-path. However, it should be taken care of resource changes between SAD(XFRM states) and routing table. In other words, When IPv4 SAD is changed does the related routing entry go to its slow-path? If not, it is reasonable to apply this patch. Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* The IP forwarding functionality.
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*
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* Version: $Id: ip_forward.c,v 1.48 2000/12/13 18:31:48 davem Exp $
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*
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* Authors: see ip.c
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*
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* Fixes:
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* Many : Split from ip.c , see ip_input.c for
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* history.
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* Dave Gregorich : NULL ip_rt_put fix for multicast
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* routing.
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* Jos Vos : Add call_out_firewall before sending,
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* use output device for accounting.
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* Jos Vos : Call forward firewall after routing
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* (always use output device).
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* Mike McLagan : Routing by source
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*/
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/skbuff.h>
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#include <linux/ip.h>
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#include <linux/icmp.h>
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#include <linux/netdevice.h>
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#include <net/sock.h>
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#include <net/ip.h>
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#include <net/tcp.h>
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#include <net/udp.h>
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#include <net/icmp.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <linux/netfilter_ipv4.h>
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#include <net/checksum.h>
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#include <linux/route.h>
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#include <net/route.h>
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#include <net/xfrm.h>
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static inline int ip_forward_finish(struct sk_buff *skb)
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{
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struct ip_options * opt = &(IPCB(skb)->opt);
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IP_INC_STATS_BH(IPSTATS_MIB_OUTFORWDATAGRAMS);
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if (unlikely(opt->optlen))
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ip_forward_options(skb);
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return dst_output(skb);
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}
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int ip_forward(struct sk_buff *skb)
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{
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struct iphdr *iph; /* Our header */
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struct rtable *rt; /* Route we use */
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struct ip_options * opt = &(IPCB(skb)->opt);
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if (!xfrm4_policy_check(NULL, XFRM_POLICY_FWD, skb))
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goto drop;
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if (IPCB(skb)->opt.router_alert && ip_call_ra_chain(skb))
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return NET_RX_SUCCESS;
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if (skb->pkt_type != PACKET_HOST)
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goto drop;
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skb_forward_csum(skb);
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/*
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* According to the RFC, we must first decrease the TTL field. If
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* that reaches zero, we must reply an ICMP control message telling
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* that the packet's lifetime expired.
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*/
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if (ip_hdr(skb)->ttl <= 1)
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goto too_many_hops;
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if (!xfrm4_route_forward(skb))
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goto drop;
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rt = (struct rtable*)skb->dst;
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if (opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
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goto sr_failed;
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if (unlikely(skb->len > dst_mtu(&rt->u.dst) &&
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(ip_hdr(skb)->frag_off & htons(IP_DF))) && !skb->local_df) {
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IP_INC_STATS(IPSTATS_MIB_FRAGFAILS);
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icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
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htonl(dst_mtu(&rt->u.dst)));
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goto drop;
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}
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/* We are about to mangle packet. Copy it! */
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if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+rt->u.dst.header_len))
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goto drop;
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iph = ip_hdr(skb);
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/* Decrease ttl after skb cow done */
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ip_decrease_ttl(iph);
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/*
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* We now generate an ICMP HOST REDIRECT giving the route
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* we calculated.
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*/
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if (rt->rt_flags&RTCF_DOREDIRECT && !opt->srr && !skb->sp)
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ip_rt_send_redirect(skb);
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skb->priority = rt_tos2priority(iph->tos);
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return NF_HOOK(PF_INET, NF_IP_FORWARD, skb, skb->dev, rt->u.dst.dev,
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ip_forward_finish);
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sr_failed:
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/*
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* Strict routing permits no gatewaying
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*/
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icmp_send(skb, ICMP_DEST_UNREACH, ICMP_SR_FAILED, 0);
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goto drop;
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too_many_hops:
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/* Tell the sender its packet died... */
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IP_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
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icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0);
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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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