/*
* ip_vs_proto_udp.c: UDP load balancing support for IPVS
*
* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
* Julian Anastasov <ja@ssi.bg>
*
* 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.
*
* Changes:
*
*/
#define KMSG_COMPONENT "IPVS"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/kernel.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/udp.h>
#include <net/ip_vs.h>
#include <net/ip.h>
#include <net/ip6_checksum.h>
static struct ip_vs_conn *
udp_conn_in_get(int af, const struct sk_buff *skb, struct ip_vs_protocol *pp,
const struct ip_vs_iphdr *iph, unsigned int proto_off,
int inverse)
{
struct ip_vs_conn *cp;
__be16 _ports[2], *pptr;
pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
if (pptr == NULL)
return NULL;
if (likely(!inverse)) {
cp = ip_vs_conn_in_get(af, iph->protocol,
&iph->saddr, pptr[0],
&iph->daddr, pptr[1]);
} else {
cp = ip_vs_conn_in_get(af, iph->protocol,
&iph->daddr, pptr[1],
&iph->saddr, pptr[0]);
}
return cp;
}
static struct ip_vs_conn *
udp_conn_out_get(int af, const struct sk_buff *skb, struct ip_vs_protocol *pp,
const struct ip_vs_iphdr *iph, unsigned int proto_off,
int inverse)
{
struct ip_vs_conn *cp;
__be16 _ports[2], *pptr;
pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
if (pptr == NULL)
return NULL;
if (likely(!inverse)) {
cp = ip_vs_conn_out_get(af, iph->protocol,
&iph->saddr, pptr[0],
&iph->daddr, pptr[1]);
} else {
cp = ip_vs_conn_out_get(af, iph->protocol,
&iph->daddr, pptr[1],
&iph->saddr, pptr[0]);
}
return cp;
}
static int
udp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_protocol *pp,
int *verdict, struct ip_vs_conn **cpp)
{
struct ip_vs_service *svc;
struct udphdr _udph, *uh;
struct ip_vs_iphdr iph;
ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
uh = skb_header_pointer(skb, iph.len, sizeof(_udph), &_udph);
if (uh == NULL) {
*verdict = NF_DROP;
return 0;
}
svc = ip_vs_service_get(af, skb->mark, iph.protocol,
&iph.daddr, uh->dest);
if (svc) {
if (ip_vs_todrop()) {
/*
* It seems that we are very loaded.
* We have to drop this packet :(
*/
ip_vs_service_put(svc);
*verdict = NF_DROP;
return 0;
}
/*
* Let the virtual server select a real server for the
* incoming connection, and create a connection entry.
*/
*cpp = ip_vs_schedule(svc, skb);
if (!*cpp) {
*verdict = ip_vs_leave(svc, skb, pp);
return 0;
}
ip_vs_service_put(svc);
}
return 1;
}
static inline void
udp_fast_csum_update(int af, struct udphdr *uhdr,
const union nf_inet_addr *oldip,
const union nf_inet_addr *newip,
__be16 oldport, __be16 newport)
{
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6)
uhdr->check =
csum_fold(ip_vs_check_diff16(oldip->ip6, newip->ip6,
ip_vs_check_diff2(oldport, newport,
~csum_unfold(uhdr->check))));
else
#endif
uhdr->check =
csum_fold(ip_vs_check_diff4(oldip->ip, newip->ip,
ip_vs_check_diff2(oldport, newport,
~csum_unfold(uhdr->check))));
if (!uhdr->check)
uhdr->check = CSUM_MANGLED_0;
}
static inline void
udp_partial_csum_update(int af, struct udphdr *uhdr,
const union nf_inet_addr *oldip,
const union nf_inet_addr *newip,
__be16 oldlen, __be16 newlen)
{
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6)
uhdr->check =
csum_fold(ip_vs_check_diff16(oldip->ip6, newip->ip6,
ip_vs_check_diff2(oldlen, newlen,
~csum_unfold(uhdr->check))));
else
#endif
uhdr->check =
csum_fold(ip_vs_check_diff4(oldip->ip, newip->ip,
ip_vs_check_diff2(oldlen, newlen,
~csum_unfold(uhdr->check))));
}
static int
udp_snat_handler(struct sk_buff *skb,
struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
{
struct udphdr *udph;
unsigned int udphoff;
int oldlen;
#ifdef CONFIG_IP_VS_IPV6
if (cp->af == AF_INET6)
udphoff = sizeof(struct ipv6hdr);
else
#endif
udphoff = ip_hdrlen(skb);
oldlen = skb->len - udphoff;
/* csum_check requires unshared skb */
if (!skb_make_writable(skb, udphoff+sizeof(*udph)))
return 0;
if (unlikely(cp->app != NULL)) {
/* Some checks before mangling */
if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
return 0;
/*
* Call application helper if needed
*/
if (!ip_vs_app_pkt_out(cp, skb))
return 0;
}
udph = (void *)skb_network_header(skb) + udphoff;
udph->source = cp->vport;
/*
* Adjust UDP checksums
*/
if (skb->ip_summed == CHECKSUM_PARTIAL) {
udp_partial_csum_update(cp->af, udph, &cp->daddr, &cp->vaddr,
htons(oldlen),
htons(skb->len - udphoff));
} else if (!cp->app && (udph->check != 0)) {
/* Only port and addr are changed, do fast csum update */
udp_fast_csum_update(cp->af, udph, &cp->daddr, &cp->vaddr,
cp->dport, cp->vport);
if (skb->ip_summed == CHECKSUM_COMPLETE)
skb->ip_summed = CHECKSUM_NONE;
} else {
/* full checksum calculation */
udph->check = 0;
skb->csum = skb_checksum(skb, udphoff, skb->len - udphoff, 0);
#ifdef CONFIG_IP_VS_IPV6
if (cp->af == AF_INET6)
udph->check = csum_ipv6_magic(&cp->vaddr.in6,
&cp->caddr.in6,
skb->len - udphoff,
cp->protocol, skb->csum);
else
#endif
udph->check = csum_tcpudp_magic(cp->vaddr.ip,
cp->caddr.ip,
skb->len - udphoff,
cp->protocol,
skb->csum);
if (udph->check == 0)
udph->check = CSUM_MANGLED_0;
IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
pp->name, udph->check,
(char*)&(udph->check) - (char*)udph);
}
return 1;
}
static int
udp_dnat_handler(struct sk_buff *skb,
struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
{
struct udphdr *udph;
unsigned int udphoff;
int oldlen;
#ifdef CONFIG_IP_VS_IPV6
if (cp->af == AF_INET6)
udphoff = sizeof(struct ipv6hdr);
else
#endif
udphoff = ip_hdrlen(skb);
oldlen = skb->len - udphoff;
/* csum_check requires unshared skb */
if (!skb_make_writable(skb, udphoff+sizeof(*udph)))
return 0;
if (unlikely(cp->app != NULL)) {
/* Some checks before mangling */
if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
return 0;
/*
* Attempt ip_vs_app call.
* It will fix ip_vs_conn
*/
if (!ip_vs_app_pkt_in(cp, skb))
return 0;
}
udph = (void *)skb_network_header(skb) + udphoff;
udph->dest = cp->dport;
/*
* Adjust UDP checksums
*/
if (skb->ip_summed == CHECKSUM_PARTIAL) {
udp_partial_csum_update(cp->af, udph, &cp->daddr, &cp->vaddr,
htons(oldlen),
htons(skb->len - udphoff));
} else if (!cp->app && (udph->check != 0)) {
/* Only port and addr are changed, do fast csum update */
udp_fast_csum_update(cp->af, udph, &cp->vaddr, &cp->daddr,
cp->vport, cp->dport);
if (skb->ip_summed == CHECKSUM_COMPLETE)
skb->ip_summed = CHECKSUM_NONE;
} else {
/* full checksum calculation */
udph->check = 0;
skb->csum = skb_checksum(skb, udphoff, skb->len - udphoff, 0);
#ifdef CONFIG_IP_VS_IPV6
if (cp->af == AF_INET6)
udph->check = csum_ipv6_magic(&cp->caddr.in6,
&cp->daddr.in6,
skb->len - udphoff,
cp->protocol, skb->csum);
else
#endif
udph->check = csum_tcpudp_magic(cp->caddr.ip,
cp->daddr.ip,
skb->len - udphoff,
cp->protocol,
skb->csum);
if (udph->check == 0)
udph->check = CSUM_MANGLED_0;
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
return 1;
}
static int
udp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp)
{
struct udphdr _udph, *uh;
unsigned int udphoff;
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6)
udphoff = sizeof(struct ipv6hdr);
else
#endif
udphoff = ip_hdrlen(skb);
uh = skb_header_pointer(skb, udphoff, sizeof(_udph), &_udph);
if (uh == NULL)
return 0;
if (uh->check != 0) {
switch (skb->ip_summed) {
case CHECKSUM_NONE:
skb->csum = skb_checksum(skb, udphoff,
skb->len - udphoff, 0);
case CHECKSUM_COMPLETE:
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6) {
if (csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
&ipv6_hdr(skb)->daddr,
skb->len - udphoff,
ipv6_hdr(skb)->nexthdr,
skb->csum)) {
IP_VS_DBG_RL_PKT(0, pp, skb, 0,
"Failed checksum for");
return 0;
}
} else
#endif
if (csum_tcpudp_magic(ip_hdr(skb)->saddr,
ip_hdr(skb)->daddr,
skb->len - udphoff,
ip_hdr(skb)->protocol,
skb->csum)) {
IP_VS_DBG_RL_PKT(0, pp, skb, 0,
"Failed checksum for");
return 0;
}
break;
default:
/* No need to checksum. */
break;
}
}
return 1;
}
/*
* Note: the caller guarantees that only one of register_app,
* unregister_app or app_conn_bind is called each time.
*/
#define UDP_APP_TAB_BITS 4
#define UDP_APP_TAB_SIZE (1 << UDP_APP_TAB_BITS)
#define UDP_APP_TAB_MASK (UDP_APP_TAB_SIZE - 1)
static struct list_head udp_apps[UDP_APP_TAB_SIZE];
static DEFINE_SPINLOCK(udp_app_lock);
static inline __u16 udp_app_hashkey(__be16 port)
{
return (((__force u16)port >> UDP_APP_TAB_BITS) ^ (__force u16)port)
& UDP_APP_TAB_MASK;
}
static int udp_register_app(struct ip_vs_app *inc)
{
struct ip_vs_app *i;
__u16 hash;
__be16 port = inc->port;
int ret = 0;
hash = udp_app_hashkey(port);
spin_lock_bh(&udp_app_lock);
list_for_each_entry(i, &udp_apps[hash], p_list) {
if (i->port == port) {
ret = -EEXIST;
goto out;
}
}
list_add(&inc->p_list, &udp_apps[hash]);
atomic_inc(&ip_vs_protocol_udp.appcnt);
out:
spin_unlock_bh(&udp_app_lock);
return ret;
}
static void
udp_unregister_app(struct ip_vs_app *inc)
{
spin_lock_bh(&udp_app_lock);
atomic_dec(&ip_vs_protocol_udp.appcnt);
list_del(&inc->p_list);
spin_unlock_bh(&udp_app_lock);
}
static int udp_app_conn_bind(struct ip_vs_conn *cp)
{
int hash;
struct ip_vs_app *inc;
int result = 0;
/* Default binding: bind app only for NAT */
if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
return 0;
/* Lookup application incarnations and bind the right one */
hash = udp_app_hashkey(cp->vport);
spin_lock(&udp_app_lock);
list_for_each_entry(inc, &udp_apps[hash], p_list) {
if (inc->port == cp->vport) {
if (unlikely(!ip_vs_app_inc_get(inc)))
break;
spin_unlock(&udp_app_lock);
IP_VS_DBG_BUF(9, "%s(): Binding conn %s:%u->"
"%s:%u to app %s on port %u\n",
__func__,
IP_VS_DBG_ADDR(cp->af, &cp->caddr),
ntohs(cp->cport),
IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
ntohs(cp->vport),
inc->name, ntohs(inc->port));
cp->app = inc;
if (inc->init_conn)
result = inc->init_conn(inc, cp);
goto out;
}
}
spin_unlock(&udp_app_lock);
out:
return result;
}
static int udp_timeouts[IP_VS_UDP_S_LAST+1] = {
[IP_VS_UDP_S_NORMAL] = 5*60*HZ,
[IP_VS_UDP_S_LAST] = 2*HZ,
};
static const char *const udp_state_name_table[IP_VS_UDP_S_LAST+1] = {
[IP_VS_UDP_S_NORMAL] = "UDP",
[IP_VS_UDP_S_LAST] = "BUG!",
};
static int
udp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
{
return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_UDP_S_LAST,
udp_state_name_table, sname, to);
}
static const char * udp_state_name(int state)
{
if (state >= IP_VS_UDP_S_LAST)
return "ERR!";
return udp_state_name_table[state] ? udp_state_name_table[state] : "?";
}
static int
udp_state_transition(struct ip_vs_conn *cp, int direction,
const struct sk_buff *skb,
struct ip_vs_protocol *pp)
{
cp->timeout = pp->timeout_table[IP_VS_UDP_S_NORMAL];
return 1;
}
static void udp_init(struct ip_vs_protocol *pp)
{
IP_VS_INIT_HASH_TABLE(udp_apps);
pp->timeout_table = udp_timeouts;
}
static void udp_exit(struct ip_vs_protocol *pp)
{
}
struct ip_vs_protocol ip_vs_protocol_udp = {
.name = "UDP",
.protocol = IPPROTO_UDP,
.num_states = IP_VS_UDP_S_LAST,
.dont_defrag = 0,
.init = udp_init,
.exit = udp_exit,
.conn_schedule = udp_conn_schedule,
.conn_in_get = udp_conn_in_get,
.conn_out_get = udp_conn_out_get,
.snat_handler = udp_snat_handler,
.dnat_handler = udp_dnat_handler,
.csum_check = udp_csum_check,
.state_transition = udp_state_transition,
.state_name = udp_state_name,
.register_app = udp_register_app,
.unregister_app = udp_unregister_app,
.app_conn_bind = udp_app_conn_bind,
.debug_packet = ip_vs_tcpudp_debug_packet,
.timeout_change = NULL,
.set_state_timeout = udp_set_state_timeout,
};