2 * ip_vs_xmit.c: various packet transmitters for IPVS
4 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
5 * Julian Anastasov <ja@ssi.bg>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
14 * Description of forwarding methods:
15 * - all transmitters are called from LOCAL_IN (remote clients) and
16 * LOCAL_OUT (local clients) but for ICMP can be called from FORWARD
17 * - not all connections have destination server, for example,
18 * connections in backup server when fwmark is used
19 * - bypass connections use daddr from packet
21 * - skb->dev is NULL, skb->protocol is not set (both are set in POST_ROUTING)
22 * - skb->pkt_type is not set yet
23 * - the only place where we can see skb->sk != NULL
26 #define KMSG_COMPONENT "IPVS"
27 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
29 #include <linux/kernel.h>
30 #include <linux/slab.h>
31 #include <linux/tcp.h> /* for tcphdr */
33 #include <net/tcp.h> /* for csum_tcpudp_magic */
35 #include <net/icmp.h> /* for icmp_send */
36 #include <net/route.h> /* for ip_route_output */
38 #include <net/ip6_route.h>
39 #include <net/addrconf.h>
40 #include <linux/icmpv6.h>
41 #include <linux/netfilter.h>
42 #include <linux/netfilter_ipv4.h>
44 #include <net/ip_vs.h>
48 * Destination cache to speed up outgoing route lookup
51 __ip_vs_dst_set(struct ip_vs_dest
*dest
, u32 rtos
, struct dst_entry
*dst
,
54 struct dst_entry
*old_dst
;
56 old_dst
= dest
->dst_cache
;
57 dest
->dst_cache
= dst
;
58 dest
->dst_rtos
= rtos
;
59 dest
->dst_cookie
= dst_cookie
;
63 static inline struct dst_entry
*
64 __ip_vs_dst_check(struct ip_vs_dest
*dest
, u32 rtos
)
66 struct dst_entry
*dst
= dest
->dst_cache
;
70 if ((dst
->obsolete
|| rtos
!= dest
->dst_rtos
) &&
71 dst
->ops
->check(dst
, dest
->dst_cookie
) == NULL
) {
72 dest
->dst_cache
= NULL
;
81 * Get route to destination or remote server
82 * rt_mode: flags, &1=Allow local dest, &2=Allow non-local dest,
83 * &4=Allow redirect from remote daddr to local
85 static struct rtable
*
86 __ip_vs_get_out_rt(struct sk_buff
*skb
, struct ip_vs_dest
*dest
,
87 __be32 daddr
, u32 rtos
, int rt_mode
)
89 struct net
*net
= dev_net(skb_dst(skb
)->dev
);
90 struct rtable
*rt
; /* Route to the other host */
91 struct rtable
*ort
; /* Original route */
95 spin_lock(&dest
->dst_lock
);
96 if (!(rt
= (struct rtable
*)
97 __ip_vs_dst_check(dest
, rtos
))) {
102 .daddr
= dest
->addr
.ip
,
107 if (ip_route_output_key(net
, &rt
, &fl
)) {
108 spin_unlock(&dest
->dst_lock
);
109 IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n",
113 __ip_vs_dst_set(dest
, rtos
, dst_clone(&rt
->dst
), 0);
114 IP_VS_DBG(10, "new dst %pI4, refcnt=%d, rtos=%X\n",
116 atomic_read(&rt
->dst
.__refcnt
), rtos
);
118 spin_unlock(&dest
->dst_lock
);
129 if (ip_route_output_key(net
, &rt
, &fl
)) {
130 IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n",
136 local
= rt
->rt_flags
& RTCF_LOCAL
;
137 if (!((local
? 1 : 2) & rt_mode
)) {
138 IP_VS_DBG_RL("Stopping traffic to %s address, dest: %pI4\n",
139 (rt
->rt_flags
& RTCF_LOCAL
) ?
140 "local":"non-local", &rt
->rt_dst
);
144 if (local
&& !(rt_mode
& 4) && !((ort
= skb_rtable(skb
)) &&
145 ort
->rt_flags
& RTCF_LOCAL
)) {
146 IP_VS_DBG_RL("Redirect from non-local address %pI4 to local "
147 "requires NAT method, dest: %pI4\n",
148 &ip_hdr(skb
)->daddr
, &rt
->rt_dst
);
152 if (unlikely(!local
&& ipv4_is_loopback(ip_hdr(skb
)->saddr
))) {
153 IP_VS_DBG_RL("Stopping traffic from loopback address %pI4 "
154 "to non-local address, dest: %pI4\n",
155 &ip_hdr(skb
)->saddr
, &rt
->rt_dst
);
163 /* Reroute packet to local IPv4 stack after DNAT */
165 __ip_vs_reroute_locally(struct sk_buff
*skb
)
167 struct rtable
*rt
= skb_rtable(skb
);
168 struct net_device
*dev
= rt
->dst
.dev
;
169 struct net
*net
= dev_net(dev
);
170 struct iphdr
*iph
= ip_hdr(skb
);
173 unsigned long orefdst
= skb
->_skb_refdst
;
175 if (ip_route_input(skb
, iph
->daddr
, iph
->saddr
,
178 refdst_drop(orefdst
);
186 .tos
= RT_TOS(iph
->tos
),
193 if (ip_route_output_key(net
, &rt
, &fl
))
195 if (!(rt
->rt_flags
& RTCF_LOCAL
)) {
199 /* Drop old route. */
201 skb_dst_set(skb
, &rt
->dst
);
206 #ifdef CONFIG_IP_VS_IPV6
208 static inline int __ip_vs_is_local_route6(struct rt6_info
*rt
)
210 return rt
->rt6i_dev
&& rt
->rt6i_dev
->flags
& IFF_LOOPBACK
;
213 static struct dst_entry
*
214 __ip_vs_route_output_v6(struct net
*net
, struct in6_addr
*daddr
,
215 struct in6_addr
*ret_saddr
, int do_xfrm
)
217 struct dst_entry
*dst
;
227 dst
= ip6_route_output(net
, NULL
, &fl
);
232 if (ipv6_addr_any(&fl
.fl6_src
) &&
233 ipv6_dev_get_saddr(net
, ip6_dst_idev(dst
)->dev
,
234 &fl
.fl6_dst
, 0, &fl
.fl6_src
) < 0)
236 if (do_xfrm
&& xfrm_lookup(net
, &dst
, &fl
, NULL
, 0) < 0)
238 ipv6_addr_copy(ret_saddr
, &fl
.fl6_src
);
243 IP_VS_DBG_RL("ip6_route_output error, dest: %pI6\n", daddr
);
248 * Get route to destination or remote server
249 * rt_mode: flags, &1=Allow local dest, &2=Allow non-local dest,
250 * &4=Allow redirect from remote daddr to local
252 static struct rt6_info
*
253 __ip_vs_get_out_rt_v6(struct sk_buff
*skb
, struct ip_vs_dest
*dest
,
254 struct in6_addr
*daddr
, struct in6_addr
*ret_saddr
,
255 int do_xfrm
, int rt_mode
)
257 struct net
*net
= dev_net(skb_dst(skb
)->dev
);
258 struct rt6_info
*rt
; /* Route to the other host */
259 struct rt6_info
*ort
; /* Original route */
260 struct dst_entry
*dst
;
264 spin_lock(&dest
->dst_lock
);
265 rt
= (struct rt6_info
*)__ip_vs_dst_check(dest
, 0);
269 dst
= __ip_vs_route_output_v6(net
, &dest
->addr
.in6
,
273 spin_unlock(&dest
->dst_lock
);
276 rt
= (struct rt6_info
*) dst
;
277 cookie
= rt
->rt6i_node
? rt
->rt6i_node
->fn_sernum
: 0;
278 __ip_vs_dst_set(dest
, 0, dst_clone(&rt
->dst
), cookie
);
279 IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
280 &dest
->addr
.in6
, &dest
->dst_saddr
,
281 atomic_read(&rt
->dst
.__refcnt
));
284 ipv6_addr_copy(ret_saddr
, &dest
->dst_saddr
);
285 spin_unlock(&dest
->dst_lock
);
287 dst
= __ip_vs_route_output_v6(net
, daddr
, ret_saddr
, do_xfrm
);
290 rt
= (struct rt6_info
*) dst
;
293 local
= __ip_vs_is_local_route6(rt
);
294 if (!((local
? 1 : 2) & rt_mode
)) {
295 IP_VS_DBG_RL("Stopping traffic to %s address, dest: %pI6\n",
296 local
? "local":"non-local", daddr
);
297 dst_release(&rt
->dst
);
300 if (local
&& !(rt_mode
& 4) &&
301 !((ort
= (struct rt6_info
*) skb_dst(skb
)) &&
302 __ip_vs_is_local_route6(ort
))) {
303 IP_VS_DBG_RL("Redirect from non-local address %pI6 to local "
304 "requires NAT method, dest: %pI6\n",
305 &ipv6_hdr(skb
)->daddr
, daddr
);
306 dst_release(&rt
->dst
);
309 if (unlikely(!local
&& (!skb
->dev
|| skb
->dev
->flags
& IFF_LOOPBACK
) &&
310 ipv6_addr_type(&ipv6_hdr(skb
)->saddr
) &
311 IPV6_ADDR_LOOPBACK
)) {
312 IP_VS_DBG_RL("Stopping traffic from loopback address %pI6 "
313 "to non-local address, dest: %pI6\n",
314 &ipv6_hdr(skb
)->saddr
, daddr
);
315 dst_release(&rt
->dst
);
325 * Release dest->dst_cache before a dest is removed
328 ip_vs_dst_reset(struct ip_vs_dest
*dest
)
330 struct dst_entry
*old_dst
;
332 old_dst
= dest
->dst_cache
;
333 dest
->dst_cache
= NULL
;
334 dst_release(old_dst
);
337 #define IP_VS_XMIT_TUNNEL(skb, cp) \
339 int __ret = NF_ACCEPT; \
341 (skb)->ipvs_property = 1; \
342 if (unlikely((cp)->flags & IP_VS_CONN_F_NFCT)) \
343 __ret = ip_vs_confirm_conntrack(skb, cp); \
344 if (__ret == NF_ACCEPT) { \
346 skb_forward_csum(skb); \
351 #define IP_VS_XMIT_NAT(pf, skb, cp, local) \
353 (skb)->ipvs_property = 1; \
354 if (likely(!((cp)->flags & IP_VS_CONN_F_NFCT))) \
355 ip_vs_notrack(skb); \
357 ip_vs_update_conntrack(skb, cp, 1); \
360 skb_forward_csum(skb); \
361 NF_HOOK(pf, NF_INET_LOCAL_OUT, (skb), NULL, \
362 skb_dst(skb)->dev, dst_output); \
365 #define IP_VS_XMIT(pf, skb, cp, local) \
367 (skb)->ipvs_property = 1; \
368 if (likely(!((cp)->flags & IP_VS_CONN_F_NFCT))) \
369 ip_vs_notrack(skb); \
372 skb_forward_csum(skb); \
373 NF_HOOK(pf, NF_INET_LOCAL_OUT, (skb), NULL, \
374 skb_dst(skb)->dev, dst_output); \
379 * NULL transmitter (do nothing except return NF_ACCEPT)
382 ip_vs_null_xmit(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
383 struct ip_vs_protocol
*pp
)
385 /* we do not touch skb and do not need pskb ptr */
386 IP_VS_XMIT(NFPROTO_IPV4
, skb
, cp
, 1);
392 * Let packets bypass the destination when the destination is not
393 * available, it may be only used in transparent cache cluster.
396 ip_vs_bypass_xmit(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
397 struct ip_vs_protocol
*pp
)
399 struct rtable
*rt
; /* Route to the other host */
400 struct iphdr
*iph
= ip_hdr(skb
);
405 if (!(rt
= __ip_vs_get_out_rt(skb
, NULL
, iph
->daddr
,
406 RT_TOS(iph
->tos
), 2)))
410 mtu
= dst_mtu(&rt
->dst
);
411 if ((skb
->len
> mtu
) && (iph
->frag_off
& htons(IP_DF
))) {
413 icmp_send(skb
, ICMP_DEST_UNREACH
,ICMP_FRAG_NEEDED
, htonl(mtu
));
414 IP_VS_DBG_RL("%s(): frag needed\n", __func__
);
419 * Call ip_send_check because we are not sure it is called
420 * after ip_defrag. Is copy-on-write needed?
422 if (unlikely((skb
= skb_share_check(skb
, GFP_ATOMIC
)) == NULL
)) {
426 ip_send_check(ip_hdr(skb
));
430 skb_dst_set(skb
, &rt
->dst
);
432 /* Another hack: avoid icmp_send in ip_fragment */
435 IP_VS_XMIT(NFPROTO_IPV4
, skb
, cp
, 0);
441 dst_link_failure(skb
);
448 #ifdef CONFIG_IP_VS_IPV6
450 ip_vs_bypass_xmit_v6(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
451 struct ip_vs_protocol
*pp
)
453 struct rt6_info
*rt
; /* Route to the other host */
454 struct ipv6hdr
*iph
= ipv6_hdr(skb
);
459 if (!(rt
= __ip_vs_get_out_rt_v6(skb
, NULL
, &iph
->daddr
, NULL
, 0, 2)))
463 mtu
= dst_mtu(&rt
->dst
);
464 if (skb
->len
> mtu
) {
466 struct net
*net
= dev_net(skb_dst(skb
)->dev
);
468 skb
->dev
= net
->loopback_dev
;
470 icmpv6_send(skb
, ICMPV6_PKT_TOOBIG
, 0, mtu
);
471 dst_release(&rt
->dst
);
472 IP_VS_DBG_RL("%s(): frag needed\n", __func__
);
477 * Call ip_send_check because we are not sure it is called
478 * after ip_defrag. Is copy-on-write needed?
480 skb
= skb_share_check(skb
, GFP_ATOMIC
);
481 if (unlikely(skb
== NULL
)) {
482 dst_release(&rt
->dst
);
488 skb_dst_set(skb
, &rt
->dst
);
490 /* Another hack: avoid icmp_send in ip_fragment */
493 IP_VS_XMIT(NFPROTO_IPV6
, skb
, cp
, 0);
499 dst_link_failure(skb
);
508 * NAT transmitter (only for outside-to-inside nat forwarding)
509 * Not used for related ICMP
512 ip_vs_nat_xmit(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
513 struct ip_vs_protocol
*pp
)
515 struct rtable
*rt
; /* Route to the other host */
517 struct iphdr
*iph
= ip_hdr(skb
);
522 /* check if it is a connection of no-client-port */
523 if (unlikely(cp
->flags
& IP_VS_CONN_F_NO_CPORT
)) {
525 p
= skb_header_pointer(skb
, iph
->ihl
*4, sizeof(_pt
), &_pt
);
528 ip_vs_conn_fill_cport(cp
, *p
);
529 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p
));
532 if (!(rt
= __ip_vs_get_out_rt(skb
, cp
->dest
, cp
->daddr
.ip
,
533 RT_TOS(iph
->tos
), 1|2|4)))
535 local
= rt
->rt_flags
& RTCF_LOCAL
;
537 * Avoid duplicate tuple in reply direction for NAT traffic
538 * to local address when connection is sync-ed
540 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
541 if (cp
->flags
& IP_VS_CONN_F_SYNC
&& local
) {
542 enum ip_conntrack_info ctinfo
;
543 struct nf_conn
*ct
= ct
= nf_ct_get(skb
, &ctinfo
);
545 if (ct
&& !nf_ct_is_untracked(ct
)) {
546 IP_VS_DBG_RL_PKT(10, AF_INET
, pp
, skb
, 0,
548 "stopping DNAT to local address");
554 /* From world but DNAT to loopback address? */
555 if (local
&& ipv4_is_loopback(rt
->rt_dst
) && skb_rtable(skb
)->fl
.iif
) {
556 IP_VS_DBG_RL_PKT(1, AF_INET
, pp
, skb
, 0, "ip_vs_nat_xmit(): "
557 "stopping DNAT to loopback address");
562 mtu
= dst_mtu(&rt
->dst
);
563 if ((skb
->len
> mtu
) && (iph
->frag_off
& htons(IP_DF
))) {
564 icmp_send(skb
, ICMP_DEST_UNREACH
,ICMP_FRAG_NEEDED
, htonl(mtu
));
565 IP_VS_DBG_RL_PKT(0, AF_INET
, pp
, skb
, 0,
566 "ip_vs_nat_xmit(): frag needed for");
570 /* copy-on-write the packet before mangling it */
571 if (!skb_make_writable(skb
, sizeof(struct iphdr
)))
574 if (skb_cow(skb
, rt
->dst
.dev
->hard_header_len
))
577 /* mangle the packet */
578 if (pp
->dnat_handler
&& !pp
->dnat_handler(skb
, pp
, cp
))
580 ip_hdr(skb
)->daddr
= cp
->daddr
.ip
;
581 ip_send_check(ip_hdr(skb
));
586 skb_dst_set(skb
, &rt
->dst
);
590 * Some IPv4 replies get local address from routes,
591 * not from iph, so while we DNAT after routing
592 * we need this second input/output route.
594 if (!__ip_vs_reroute_locally(skb
))
598 IP_VS_DBG_PKT(10, AF_INET
, pp
, skb
, 0, "After DNAT");
600 /* FIXME: when application helper enlarges the packet and the length
601 is larger than the MTU of outgoing device, there will be still
604 /* Another hack: avoid icmp_send in ip_fragment */
607 IP_VS_XMIT_NAT(NFPROTO_IPV4
, skb
, cp
, local
);
613 dst_link_failure(skb
);
623 #ifdef CONFIG_IP_VS_IPV6
625 ip_vs_nat_xmit_v6(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
626 struct ip_vs_protocol
*pp
)
628 struct rt6_info
*rt
; /* Route to the other host */
634 /* check if it is a connection of no-client-port */
635 if (unlikely(cp
->flags
& IP_VS_CONN_F_NO_CPORT
)) {
637 p
= skb_header_pointer(skb
, sizeof(struct ipv6hdr
),
641 ip_vs_conn_fill_cport(cp
, *p
);
642 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p
));
645 if (!(rt
= __ip_vs_get_out_rt_v6(skb
, cp
->dest
, &cp
->daddr
.in6
, NULL
,
648 local
= __ip_vs_is_local_route6(rt
);
650 * Avoid duplicate tuple in reply direction for NAT traffic
651 * to local address when connection is sync-ed
653 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
654 if (cp
->flags
& IP_VS_CONN_F_SYNC
&& local
) {
655 enum ip_conntrack_info ctinfo
;
656 struct nf_conn
*ct
= ct
= nf_ct_get(skb
, &ctinfo
);
658 if (ct
&& !nf_ct_is_untracked(ct
)) {
659 IP_VS_DBG_RL_PKT(10, AF_INET6
, pp
, skb
, 0,
660 "ip_vs_nat_xmit_v6(): "
661 "stopping DNAT to local address");
667 /* From world but DNAT to loopback address? */
668 if (local
&& skb
->dev
&& !(skb
->dev
->flags
& IFF_LOOPBACK
) &&
669 ipv6_addr_type(&rt
->rt6i_dst
.addr
) & IPV6_ADDR_LOOPBACK
) {
670 IP_VS_DBG_RL_PKT(1, AF_INET6
, pp
, skb
, 0,
671 "ip_vs_nat_xmit_v6(): "
672 "stopping DNAT to loopback address");
677 mtu
= dst_mtu(&rt
->dst
);
678 if (skb
->len
> mtu
) {
680 struct net
*net
= dev_net(skb_dst(skb
)->dev
);
682 skb
->dev
= net
->loopback_dev
;
684 icmpv6_send(skb
, ICMPV6_PKT_TOOBIG
, 0, mtu
);
685 IP_VS_DBG_RL_PKT(0, AF_INET6
, pp
, skb
, 0,
686 "ip_vs_nat_xmit_v6(): frag needed for");
690 /* copy-on-write the packet before mangling it */
691 if (!skb_make_writable(skb
, sizeof(struct ipv6hdr
)))
694 if (skb_cow(skb
, rt
->dst
.dev
->hard_header_len
))
697 /* mangle the packet */
698 if (pp
->dnat_handler
&& !pp
->dnat_handler(skb
, pp
, cp
))
700 ipv6_addr_copy(&ipv6_hdr(skb
)->daddr
, &cp
->daddr
.in6
);
702 if (!local
|| !skb
->dev
) {
703 /* drop the old route when skb is not shared */
705 skb_dst_set(skb
, &rt
->dst
);
707 /* destined to loopback, do we need to change route? */
708 dst_release(&rt
->dst
);
711 IP_VS_DBG_PKT(10, AF_INET6
, pp
, skb
, 0, "After DNAT");
713 /* FIXME: when application helper enlarges the packet and the length
714 is larger than the MTU of outgoing device, there will be still
717 /* Another hack: avoid icmp_send in ip_fragment */
720 IP_VS_XMIT_NAT(NFPROTO_IPV6
, skb
, cp
, local
);
726 dst_link_failure(skb
);
732 dst_release(&rt
->dst
);
739 * IP Tunneling transmitter
741 * This function encapsulates the packet in a new IP packet, its
742 * destination will be set to cp->daddr. Most code of this function
743 * is taken from ipip.c.
745 * It is used in VS/TUN cluster. The load balancer selects a real
746 * server from a cluster based on a scheduling algorithm,
747 * encapsulates the request packet and forwards it to the selected
748 * server. For example, all real servers are configured with
749 * "ifconfig tunl0 <Virtual IP Address> up". When the server receives
750 * the encapsulated packet, it will decapsulate the packet, processe
751 * the request and return the response packets directly to the client
752 * without passing the load balancer. This can greatly increase the
753 * scalability of virtual server.
755 * Used for ANY protocol
758 ip_vs_tunnel_xmit(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
759 struct ip_vs_protocol
*pp
)
761 struct rtable
*rt
; /* Route to the other host */
762 struct net_device
*tdev
; /* Device to other host */
763 struct iphdr
*old_iph
= ip_hdr(skb
);
764 u8 tos
= old_iph
->tos
;
765 __be16 df
= old_iph
->frag_off
;
766 struct iphdr
*iph
; /* Our new IP header */
767 unsigned int max_headroom
; /* The extra header space needed */
773 if (!(rt
= __ip_vs_get_out_rt(skb
, cp
->dest
, cp
->daddr
.ip
,
776 if (rt
->rt_flags
& RTCF_LOCAL
) {
778 IP_VS_XMIT(NFPROTO_IPV4
, skb
, cp
, 1);
783 mtu
= dst_mtu(&rt
->dst
) - sizeof(struct iphdr
);
785 IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__
);
789 skb_dst(skb
)->ops
->update_pmtu(skb_dst(skb
), mtu
);
791 df
|= (old_iph
->frag_off
& htons(IP_DF
));
793 if ((old_iph
->frag_off
& htons(IP_DF
))
794 && mtu
< ntohs(old_iph
->tot_len
)) {
795 icmp_send(skb
, ICMP_DEST_UNREACH
,ICMP_FRAG_NEEDED
, htonl(mtu
));
796 IP_VS_DBG_RL("%s(): frag needed\n", __func__
);
801 * Okay, now see if we can stuff it in the buffer as-is.
803 max_headroom
= LL_RESERVED_SPACE(tdev
) + sizeof(struct iphdr
);
805 if (skb_headroom(skb
) < max_headroom
806 || skb_cloned(skb
) || skb_shared(skb
)) {
807 struct sk_buff
*new_skb
=
808 skb_realloc_headroom(skb
, max_headroom
);
812 IP_VS_ERR_RL("%s(): no memory\n", __func__
);
817 old_iph
= ip_hdr(skb
);
820 skb
->transport_header
= skb
->network_header
;
822 /* fix old IP header checksum */
823 ip_send_check(old_iph
);
825 skb_push(skb
, sizeof(struct iphdr
));
826 skb_reset_network_header(skb
);
827 memset(&(IPCB(skb
)->opt
), 0, sizeof(IPCB(skb
)->opt
));
831 skb_dst_set(skb
, &rt
->dst
);
834 * Push down and install the IPIP header.
838 iph
->ihl
= sizeof(struct iphdr
)>>2;
840 iph
->protocol
= IPPROTO_IPIP
;
842 iph
->daddr
= rt
->rt_dst
;
843 iph
->saddr
= rt
->rt_src
;
844 iph
->ttl
= old_iph
->ttl
;
845 ip_select_ident(iph
, &rt
->dst
, NULL
);
847 /* Another hack: avoid icmp_send in ip_fragment */
850 ret
= IP_VS_XMIT_TUNNEL(skb
, cp
);
851 if (ret
== NF_ACCEPT
)
853 else if (ret
== NF_DROP
)
861 dst_link_failure(skb
);
871 #ifdef CONFIG_IP_VS_IPV6
873 ip_vs_tunnel_xmit_v6(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
874 struct ip_vs_protocol
*pp
)
876 struct rt6_info
*rt
; /* Route to the other host */
877 struct in6_addr saddr
; /* Source for tunnel */
878 struct net_device
*tdev
; /* Device to other host */
879 struct ipv6hdr
*old_iph
= ipv6_hdr(skb
);
880 struct ipv6hdr
*iph
; /* Our new IP header */
881 unsigned int max_headroom
; /* The extra header space needed */
887 if (!(rt
= __ip_vs_get_out_rt_v6(skb
, cp
->dest
, &cp
->daddr
.in6
,
890 if (__ip_vs_is_local_route6(rt
)) {
891 dst_release(&rt
->dst
);
892 IP_VS_XMIT(NFPROTO_IPV6
, skb
, cp
, 1);
897 mtu
= dst_mtu(&rt
->dst
) - sizeof(struct ipv6hdr
);
898 if (mtu
< IPV6_MIN_MTU
) {
899 IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__
,
904 skb_dst(skb
)->ops
->update_pmtu(skb_dst(skb
), mtu
);
906 if (mtu
< ntohs(old_iph
->payload_len
) + sizeof(struct ipv6hdr
)) {
908 struct net
*net
= dev_net(skb_dst(skb
)->dev
);
910 skb
->dev
= net
->loopback_dev
;
912 icmpv6_send(skb
, ICMPV6_PKT_TOOBIG
, 0, mtu
);
913 IP_VS_DBG_RL("%s(): frag needed\n", __func__
);
918 * Okay, now see if we can stuff it in the buffer as-is.
920 max_headroom
= LL_RESERVED_SPACE(tdev
) + sizeof(struct ipv6hdr
);
922 if (skb_headroom(skb
) < max_headroom
923 || skb_cloned(skb
) || skb_shared(skb
)) {
924 struct sk_buff
*new_skb
=
925 skb_realloc_headroom(skb
, max_headroom
);
927 dst_release(&rt
->dst
);
929 IP_VS_ERR_RL("%s(): no memory\n", __func__
);
934 old_iph
= ipv6_hdr(skb
);
937 skb
->transport_header
= skb
->network_header
;
939 skb_push(skb
, sizeof(struct ipv6hdr
));
940 skb_reset_network_header(skb
);
941 memset(&(IPCB(skb
)->opt
), 0, sizeof(IPCB(skb
)->opt
));
945 skb_dst_set(skb
, &rt
->dst
);
948 * Push down and install the IPIP header.
952 iph
->nexthdr
= IPPROTO_IPV6
;
953 iph
->payload_len
= old_iph
->payload_len
;
954 be16_add_cpu(&iph
->payload_len
, sizeof(*old_iph
));
955 iph
->priority
= old_iph
->priority
;
956 memset(&iph
->flow_lbl
, 0, sizeof(iph
->flow_lbl
));
957 ipv6_addr_copy(&iph
->daddr
, &cp
->daddr
.in6
);
958 ipv6_addr_copy(&iph
->saddr
, &saddr
);
959 iph
->hop_limit
= old_iph
->hop_limit
;
961 /* Another hack: avoid icmp_send in ip_fragment */
964 ret
= IP_VS_XMIT_TUNNEL(skb
, cp
);
965 if (ret
== NF_ACCEPT
)
967 else if (ret
== NF_DROP
)
975 dst_link_failure(skb
);
981 dst_release(&rt
->dst
);
988 * Direct Routing transmitter
989 * Used for ANY protocol
992 ip_vs_dr_xmit(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
993 struct ip_vs_protocol
*pp
)
995 struct rtable
*rt
; /* Route to the other host */
996 struct iphdr
*iph
= ip_hdr(skb
);
1001 if (!(rt
= __ip_vs_get_out_rt(skb
, cp
->dest
, cp
->daddr
.ip
,
1002 RT_TOS(iph
->tos
), 1|2)))
1004 if (rt
->rt_flags
& RTCF_LOCAL
) {
1006 IP_VS_XMIT(NFPROTO_IPV4
, skb
, cp
, 1);
1010 mtu
= dst_mtu(&rt
->dst
);
1011 if ((iph
->frag_off
& htons(IP_DF
)) && skb
->len
> mtu
) {
1012 icmp_send(skb
, ICMP_DEST_UNREACH
,ICMP_FRAG_NEEDED
, htonl(mtu
));
1014 IP_VS_DBG_RL("%s(): frag needed\n", __func__
);
1019 * Call ip_send_check because we are not sure it is called
1020 * after ip_defrag. Is copy-on-write needed?
1022 if (unlikely((skb
= skb_share_check(skb
, GFP_ATOMIC
)) == NULL
)) {
1026 ip_send_check(ip_hdr(skb
));
1028 /* drop old route */
1030 skb_dst_set(skb
, &rt
->dst
);
1032 /* Another hack: avoid icmp_send in ip_fragment */
1035 IP_VS_XMIT(NFPROTO_IPV4
, skb
, cp
, 0);
1041 dst_link_failure(skb
);
1048 #ifdef CONFIG_IP_VS_IPV6
1050 ip_vs_dr_xmit_v6(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
1051 struct ip_vs_protocol
*pp
)
1053 struct rt6_info
*rt
; /* Route to the other host */
1058 if (!(rt
= __ip_vs_get_out_rt_v6(skb
, cp
->dest
, &cp
->daddr
.in6
, NULL
,
1061 if (__ip_vs_is_local_route6(rt
)) {
1062 dst_release(&rt
->dst
);
1063 IP_VS_XMIT(NFPROTO_IPV6
, skb
, cp
, 1);
1067 mtu
= dst_mtu(&rt
->dst
);
1068 if (skb
->len
> mtu
) {
1070 struct net
*net
= dev_net(skb_dst(skb
)->dev
);
1072 skb
->dev
= net
->loopback_dev
;
1074 icmpv6_send(skb
, ICMPV6_PKT_TOOBIG
, 0, mtu
);
1075 dst_release(&rt
->dst
);
1076 IP_VS_DBG_RL("%s(): frag needed\n", __func__
);
1081 * Call ip_send_check because we are not sure it is called
1082 * after ip_defrag. Is copy-on-write needed?
1084 skb
= skb_share_check(skb
, GFP_ATOMIC
);
1085 if (unlikely(skb
== NULL
)) {
1086 dst_release(&rt
->dst
);
1090 /* drop old route */
1092 skb_dst_set(skb
, &rt
->dst
);
1094 /* Another hack: avoid icmp_send in ip_fragment */
1097 IP_VS_XMIT(NFPROTO_IPV6
, skb
, cp
, 0);
1103 dst_link_failure(skb
);
1113 * ICMP packet transmitter
1114 * called by the ip_vs_in_icmp
1117 ip_vs_icmp_xmit(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
1118 struct ip_vs_protocol
*pp
, int offset
)
1120 struct rtable
*rt
; /* Route to the other host */
1127 /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1128 forwarded directly here, because there is no need to
1129 translate address/port back */
1130 if (IP_VS_FWD_METHOD(cp
) != IP_VS_CONN_F_MASQ
) {
1131 if (cp
->packet_xmit
)
1132 rc
= cp
->packet_xmit(skb
, cp
, pp
);
1135 /* do not touch skb anymore */
1136 atomic_inc(&cp
->in_pkts
);
1141 * mangle and send the packet here (only for VS/NAT)
1144 if (!(rt
= __ip_vs_get_out_rt(skb
, cp
->dest
, cp
->daddr
.ip
,
1145 RT_TOS(ip_hdr(skb
)->tos
), 1|2|4)))
1147 local
= rt
->rt_flags
& RTCF_LOCAL
;
1150 * Avoid duplicate tuple in reply direction for NAT traffic
1151 * to local address when connection is sync-ed
1153 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1154 if (cp
->flags
& IP_VS_CONN_F_SYNC
&& local
) {
1155 enum ip_conntrack_info ctinfo
;
1156 struct nf_conn
*ct
= ct
= nf_ct_get(skb
, &ctinfo
);
1158 if (ct
&& !nf_ct_is_untracked(ct
)) {
1159 IP_VS_DBG(10, "%s(): "
1160 "stopping DNAT to local address %pI4\n",
1161 __func__
, &cp
->daddr
.ip
);
1167 /* From world but DNAT to loopback address? */
1168 if (local
&& ipv4_is_loopback(rt
->rt_dst
) && skb_rtable(skb
)->fl
.iif
) {
1169 IP_VS_DBG(1, "%s(): "
1170 "stopping DNAT to loopback %pI4\n",
1171 __func__
, &cp
->daddr
.ip
);
1176 mtu
= dst_mtu(&rt
->dst
);
1177 if ((skb
->len
> mtu
) && (ip_hdr(skb
)->frag_off
& htons(IP_DF
))) {
1178 icmp_send(skb
, ICMP_DEST_UNREACH
, ICMP_FRAG_NEEDED
, htonl(mtu
));
1179 IP_VS_DBG_RL("%s(): frag needed\n", __func__
);
1183 /* copy-on-write the packet before mangling it */
1184 if (!skb_make_writable(skb
, offset
))
1187 if (skb_cow(skb
, rt
->dst
.dev
->hard_header_len
))
1190 ip_vs_nat_icmp(skb
, pp
, cp
, 0);
1193 /* drop the old route when skb is not shared */
1195 skb_dst_set(skb
, &rt
->dst
);
1199 * Some IPv4 replies get local address from routes,
1200 * not from iph, so while we DNAT after routing
1201 * we need this second input/output route.
1203 if (!__ip_vs_reroute_locally(skb
))
1207 /* Another hack: avoid icmp_send in ip_fragment */
1210 IP_VS_XMIT_NAT(NFPROTO_IPV4
, skb
, cp
, local
);
1216 dst_link_failure(skb
);
1228 #ifdef CONFIG_IP_VS_IPV6
1230 ip_vs_icmp_xmit_v6(struct sk_buff
*skb
, struct ip_vs_conn
*cp
,
1231 struct ip_vs_protocol
*pp
, int offset
)
1233 struct rt6_info
*rt
; /* Route to the other host */
1240 /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1241 forwarded directly here, because there is no need to
1242 translate address/port back */
1243 if (IP_VS_FWD_METHOD(cp
) != IP_VS_CONN_F_MASQ
) {
1244 if (cp
->packet_xmit
)
1245 rc
= cp
->packet_xmit(skb
, cp
, pp
);
1248 /* do not touch skb anymore */
1249 atomic_inc(&cp
->in_pkts
);
1254 * mangle and send the packet here (only for VS/NAT)
1257 if (!(rt
= __ip_vs_get_out_rt_v6(skb
, cp
->dest
, &cp
->daddr
.in6
, NULL
,
1261 local
= __ip_vs_is_local_route6(rt
);
1263 * Avoid duplicate tuple in reply direction for NAT traffic
1264 * to local address when connection is sync-ed
1266 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1267 if (cp
->flags
& IP_VS_CONN_F_SYNC
&& local
) {
1268 enum ip_conntrack_info ctinfo
;
1269 struct nf_conn
*ct
= ct
= nf_ct_get(skb
, &ctinfo
);
1271 if (ct
&& !nf_ct_is_untracked(ct
)) {
1272 IP_VS_DBG(10, "%s(): "
1273 "stopping DNAT to local address %pI6\n",
1274 __func__
, &cp
->daddr
.in6
);
1280 /* From world but DNAT to loopback address? */
1281 if (local
&& skb
->dev
&& !(skb
->dev
->flags
& IFF_LOOPBACK
) &&
1282 ipv6_addr_type(&rt
->rt6i_dst
.addr
) & IPV6_ADDR_LOOPBACK
) {
1283 IP_VS_DBG(1, "%s(): "
1284 "stopping DNAT to loopback %pI6\n",
1285 __func__
, &cp
->daddr
.in6
);
1290 mtu
= dst_mtu(&rt
->dst
);
1291 if (skb
->len
> mtu
) {
1293 struct net
*net
= dev_net(skb_dst(skb
)->dev
);
1295 skb
->dev
= net
->loopback_dev
;
1297 icmpv6_send(skb
, ICMPV6_PKT_TOOBIG
, 0, mtu
);
1298 IP_VS_DBG_RL("%s(): frag needed\n", __func__
);
1302 /* copy-on-write the packet before mangling it */
1303 if (!skb_make_writable(skb
, offset
))
1306 if (skb_cow(skb
, rt
->dst
.dev
->hard_header_len
))
1309 ip_vs_nat_icmp_v6(skb
, pp
, cp
, 0);
1311 if (!local
|| !skb
->dev
) {
1312 /* drop the old route when skb is not shared */
1314 skb_dst_set(skb
, &rt
->dst
);
1316 /* destined to loopback, do we need to change route? */
1317 dst_release(&rt
->dst
);
1320 /* Another hack: avoid icmp_send in ip_fragment */
1323 IP_VS_XMIT_NAT(NFPROTO_IPV6
, skb
, cp
, local
);
1329 dst_link_failure(skb
);
1337 dst_release(&rt
->dst
);