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ipvs: load balance IPv4 connections from a local process

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This allows IPVS to load balance connections made by a local process.
For example a proxy server running locally.

External client --> pound:443 -> Local:443 --> IPVS:80 --> RealServer

Signed-off-by: Siim Põder <siim@p6drad-teel.net>
Signed-off-by: Malcolm Turnbull <malcolm@loadbalancer.org>
Signed-off-by: Simon Horman <horms@verge.net.au>
This commit is contained in:
Malcolm Turnbull 2008-09-05 11:17:13 +10:00 committed by Simon Horman
parent f94fd04140
commit 4856c84c13
2 changed files with 134 additions and 94 deletions
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224
net/ipv4/ipvs/ip_vs_core.c
View file

@ -651,12 +651,53 @@ void ip_vs_nat_icmp_v6(struct sk_buff *skb, struct ip_vs_protocol *pp,
}
#endif
/* Handle relevant response ICMP messages - forward to the right
* destination host. Used for NAT and local client.
*/
static int handle_response_icmp(struct sk_buff *skb, struct iphdr *iph,
struct iphdr *cih, struct ip_vs_conn *cp,
struct ip_vs_protocol *pp,
unsigned int offset, unsigned int ihl)
{
unsigned int verdict = NF_DROP;
if (IP_VS_FWD_METHOD(cp) != 0) {
IP_VS_ERR("shouldn't reach here, because the box is on the "
"half connection in the tun/dr module.\n");
}
/* Ensure the checksum is correct */
if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
/* Failed checksum! */
IP_VS_DBG(1,
"Forward ICMP: failed checksum from %d.%d.%d.%d!\n",
NIPQUAD(iph->saddr));
goto out;
}
if (IPPROTO_TCP == cih->protocol || IPPROTO_UDP == cih->protocol)
offset += 2 * sizeof(__u16);
if (!skb_make_writable(skb, offset))
goto out;
ip_vs_nat_icmp(skb, pp, cp, 1);
/* do the statistics and put it back */
ip_vs_out_stats(cp, skb);
skb->ipvs_property = 1;
verdict = NF_ACCEPT;
out:
__ip_vs_conn_put(cp);
return verdict;
}
/*
* Handle ICMP messages in the inside-to-outside direction (outgoing).
* Find any that might be relevant, check against existing connections,
* forward to the right destination host if relevant.
* Find any that might be relevant, check against existing connections.
* Currently handles error types - unreachable, quench, ttl exceeded.
* (Only used in VS/NAT)
*/
static int ip_vs_out_icmp(struct sk_buff *skb, int *related)
{
@ -666,7 +707,7 @@ static int ip_vs_out_icmp(struct sk_buff *skb, int *related)
struct ip_vs_iphdr ciph;
struct ip_vs_conn *cp;
struct ip_vs_protocol *pp;
unsigned int offset, ihl, verdict;
unsigned int offset, ihl;
*related = 1;
@ -725,38 +766,7 @@ static int ip_vs_out_icmp(struct sk_buff *skb, int *related)
if (!cp)
return NF_ACCEPT;
verdict = NF_DROP;
if (IP_VS_FWD_METHOD(cp) != 0) {
IP_VS_ERR("shouldn't reach here, because the box is on the "
"half connection in the tun/dr module.\n");
}
/* Ensure the checksum is correct */
if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
/* Failed checksum! */
IP_VS_DBG(1, "Forward ICMP: failed checksum from %d.%d.%d.%d!\n",
NIPQUAD(iph->saddr));
goto out;
}
if (IPPROTO_TCP == cih->protocol || IPPROTO_UDP == cih->protocol)
offset += 2 * sizeof(__u16);
if (!skb_make_writable(skb, offset))
goto out;
ip_vs_nat_icmp(skb, pp, cp, 1);
/* do the statistics and put it back */
ip_vs_out_stats(cp, skb);
skb->ipvs_property = 1;
verdict = NF_ACCEPT;
out:
__ip_vs_conn_put(cp);
return verdict;
return handle_response_icmp(skb, iph, cih, cp, pp, offset, ihl);
}
#ifdef CONFIG_IP_VS_IPV6
@ -875,10 +885,76 @@ static inline int is_tcp_reset(const struct sk_buff *skb, int nh_len)
return th->rst;
}
/* Handle response packets: rewrite addresses and send away...
* Used for NAT and local client.
*/
static unsigned int
handle_response(int af, struct sk_buff *skb, struct ip_vs_protocol *pp,
struct ip_vs_conn *cp, int ihl)
{
IP_VS_DBG_PKT(11, pp, skb, 0, "Outgoing packet");
if (!skb_make_writable(skb, ihl))
goto drop;
/* mangle the packet */
if (pp->snat_handler && !pp->snat_handler(skb, pp, cp))
goto drop;
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6)
ipv6_hdr(skb)->saddr = cp->vaddr.in6;
else
#endif
{
ip_hdr(skb)->saddr = cp->vaddr.ip;
ip_send_check(ip_hdr(skb));
}
/* For policy routing, packets originating from this
* machine itself may be routed differently to packets
* passing through. We want this packet to be routed as
* if it came from this machine itself. So re-compute
* the routing information.
*/
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6) {
if (ip6_route_me_harder(skb) != 0)
goto drop;
} else
#endif
if (ip_route_me_harder(skb, RTN_LOCAL) != 0)
goto drop;
/* For policy routing, packets originating from this
* machine itself may be routed differently to packets
* passing through. We want this packet to be routed as
* if it came from this machine itself. So re-compute
* the routing information.
*/
if (ip_route_me_harder(skb, RTN_LOCAL) != 0)
goto drop;
IP_VS_DBG_PKT(10, pp, skb, 0, "After SNAT");
ip_vs_out_stats(cp, skb);
ip_vs_set_state(cp, IP_VS_DIR_OUTPUT, skb, pp);
ip_vs_conn_put(cp);
skb->ipvs_property = 1;
LeaveFunction(11);
return NF_ACCEPT;
drop:
ip_vs_conn_put(cp);
kfree_skb(skb);
return NF_STOLEN;
}
/*
* It is hooked at the NF_INET_FORWARD chain, used only for VS/NAT.
* Check if outgoing packet belongs to the established ip_vs_conn,
* rewrite addresses of the packet and send it on its way...
* Check if outgoing packet belongs to the established ip_vs_conn.
*/
static unsigned int
ip_vs_out(unsigned int hooknum, struct sk_buff *skb,
@ -987,55 +1063,7 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb,
return NF_ACCEPT;
}
IP_VS_DBG_PKT(11, pp, skb, 0, "Outgoing packet");
if (!skb_make_writable(skb, iph.len))
goto drop;
/* mangle the packet */
if (pp->snat_handler && !pp->snat_handler(skb, pp, cp))
goto drop;
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6)
ipv6_hdr(skb)->saddr = cp->vaddr.in6;
else
#endif
{
ip_hdr(skb)->saddr = cp->vaddr.ip;
ip_send_check(ip_hdr(skb));
}
/* For policy routing, packets originating from this
* machine itself may be routed differently to packets
* passing through. We want this packet to be routed as
* if it came from this machine itself. So re-compute
* the routing information.
*/
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6) {
if (ip6_route_me_harder(skb) != 0)
goto drop;
} else
#endif
if (ip_route_me_harder(skb, RTN_LOCAL) != 0)
goto drop;
IP_VS_DBG_PKT(10, pp, skb, 0, "After SNAT");
ip_vs_out_stats(cp, skb);
ip_vs_set_state(cp, IP_VS_DIR_OUTPUT, skb, pp);
ip_vs_conn_put(cp);
skb->ipvs_property = 1;
LeaveFunction(11);
return NF_ACCEPT;
drop:
ip_vs_conn_put(cp);
kfree_skb(skb);
return NF_STOLEN;
return handle_response(af, skb, pp, cp, iph.len);
}
@ -1111,8 +1139,14 @@ ip_vs_in_icmp(struct sk_buff *skb, int *related, unsigned int hooknum)
ip_vs_fill_iphdr(AF_INET, cih, &ciph);
/* The embedded headers contain source and dest in reverse order */
cp = pp->conn_in_get(AF_INET, skb, pp, &ciph, offset, 1);
if (!cp)
if (!cp) {
/* The packet could also belong to a local client */
cp = pp->conn_out_get(AF_INET, skb, pp, &ciph, offset, 1);
if (cp)
return handle_response_icmp(skb, iph, cih, cp, pp,
offset, ihl);
return NF_ACCEPT;
}
verdict = NF_DROP;
@ -1244,11 +1278,12 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb,
ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
/*
* Big tappo: only PACKET_HOST (neither loopback nor mcasts)
* ... don't know why 1st test DOES NOT include 2nd (?)
* Big tappo: only PACKET_HOST, including loopback for local client
* Don't handle local packets on IPv6 for now
*/
if (unlikely(skb->pkt_type != PACKET_HOST
|| skb->dev->flags & IFF_LOOPBACK || skb->sk)) {
if (unlikely(skb->pkt_type != PACKET_HOST ||
(af == AF_INET6 || (skb->dev->flags & IFF_LOOPBACK ||
skb->sk)))) {
IP_VS_DBG_BUF(12, "packet type=%d proto=%d daddr=%s ignored\n",
skb->pkt_type,
iph.protocol,
@ -1277,6 +1312,11 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb,
if (unlikely(!cp)) {
int v;
/* For local client packets, it could be a response */
cp = pp->conn_out_get(af, skb, pp, &iph, iph.len, 0);
if (cp)
return handle_response(af, skb, pp, cp, iph.len);
if (!pp->conn_schedule(af, skb, pp, &v, &cp))
return v;
}

4
net/ipv4/ipvs/ip_vs_proto_tcp.c
View file

@ -166,7 +166,7 @@ tcp_snat_handler(struct sk_buff *skb,
tcph->source = cp->vport;
/* Adjust TCP checksums */
if (!cp->app) {
if (!cp->app && (tcph->check != 0)) {
/* Only port and addr are changed, do fast csum update */
tcp_fast_csum_update(cp->af, tcph, &cp->daddr, &cp->vaddr,
cp->dport, cp->vport);
@ -235,7 +235,7 @@ tcp_dnat_handler(struct sk_buff *skb,
/*
* Adjust TCP checksums
*/
if (!cp->app) {
if (!cp->app && (tcph->check != 0)) {
/* Only port and addr are changed, do fast csum update */
tcp_fast_csum_update(cp->af, tcph, &cp->vaddr, &cp->daddr,
cp->vport, cp->dport);