433 lines
10 KiB
C
433 lines
10 KiB
C
/*
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* ip_vs_proto_udp.c: UDP load balancing support for IPVS
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*
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* Version: $Id: ip_vs_proto_udp.c,v 1.3 2002/11/30 01:50:35 wensong Exp $
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*
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* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
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* Julian Anastasov <ja@ssi.bg>
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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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* Changes:
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*
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*/
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/kernel.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/udp.h>
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#include <net/ip_vs.h>
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#include <net/ip.h>
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static struct ip_vs_conn *
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udp_conn_in_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
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const struct iphdr *iph, unsigned int proto_off, int inverse)
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{
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struct ip_vs_conn *cp;
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__be16 _ports[2], *pptr;
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pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
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if (pptr == NULL)
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return NULL;
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if (likely(!inverse)) {
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cp = ip_vs_conn_in_get(iph->protocol,
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iph->saddr, pptr[0],
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iph->daddr, pptr[1]);
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} else {
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cp = ip_vs_conn_in_get(iph->protocol,
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iph->daddr, pptr[1],
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iph->saddr, pptr[0]);
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}
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return cp;
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}
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static struct ip_vs_conn *
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udp_conn_out_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
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const struct iphdr *iph, unsigned int proto_off, int inverse)
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{
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struct ip_vs_conn *cp;
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__be16 _ports[2], *pptr;
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pptr = skb_header_pointer(skb, ip_hdrlen(skb),
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sizeof(_ports), _ports);
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if (pptr == NULL)
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return NULL;
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if (likely(!inverse)) {
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cp = ip_vs_conn_out_get(iph->protocol,
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iph->saddr, pptr[0],
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iph->daddr, pptr[1]);
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} else {
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cp = ip_vs_conn_out_get(iph->protocol,
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iph->daddr, pptr[1],
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iph->saddr, pptr[0]);
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}
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return cp;
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}
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static int
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udp_conn_schedule(struct sk_buff *skb, struct ip_vs_protocol *pp,
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int *verdict, struct ip_vs_conn **cpp)
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{
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struct ip_vs_service *svc;
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struct udphdr _udph, *uh;
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uh = skb_header_pointer(skb, ip_hdrlen(skb),
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sizeof(_udph), &_udph);
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if (uh == NULL) {
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*verdict = NF_DROP;
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return 0;
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}
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if ((svc = ip_vs_service_get(skb->mark, ip_hdr(skb)->protocol,
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ip_hdr(skb)->daddr, uh->dest))) {
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if (ip_vs_todrop()) {
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/*
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* It seems that we are very loaded.
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* We have to drop this packet :(
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*/
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ip_vs_service_put(svc);
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*verdict = NF_DROP;
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return 0;
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}
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/*
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* Let the virtual server select a real server for the
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* incoming connection, and create a connection entry.
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*/
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*cpp = ip_vs_schedule(svc, skb);
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if (!*cpp) {
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*verdict = ip_vs_leave(svc, skb, pp);
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return 0;
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}
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ip_vs_service_put(svc);
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}
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return 1;
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}
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static inline void
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udp_fast_csum_update(struct udphdr *uhdr, __be32 oldip, __be32 newip,
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__be16 oldport, __be16 newport)
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{
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uhdr->check =
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csum_fold(ip_vs_check_diff4(oldip, newip,
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ip_vs_check_diff2(oldport, newport,
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~csum_unfold(uhdr->check))));
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if (!uhdr->check)
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uhdr->check = CSUM_MANGLED_0;
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}
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static int
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udp_snat_handler(struct sk_buff **pskb,
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struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
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{
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struct udphdr *udph;
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const unsigned int udphoff = ip_hdrlen(*pskb);
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/* csum_check requires unshared skb */
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if (!ip_vs_make_skb_writable(pskb, udphoff+sizeof(*udph)))
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return 0;
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if (unlikely(cp->app != NULL)) {
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/* Some checks before mangling */
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if (pp->csum_check && !pp->csum_check(*pskb, pp))
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return 0;
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/*
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* Call application helper if needed
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*/
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if (!ip_vs_app_pkt_out(cp, pskb))
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return 0;
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}
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udph = (void *)ip_hdr(*pskb) + udphoff;
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udph->source = cp->vport;
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/*
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* Adjust UDP checksums
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*/
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if (!cp->app && (udph->check != 0)) {
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/* Only port and addr are changed, do fast csum update */
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udp_fast_csum_update(udph, cp->daddr, cp->vaddr,
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cp->dport, cp->vport);
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if ((*pskb)->ip_summed == CHECKSUM_COMPLETE)
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(*pskb)->ip_summed = CHECKSUM_NONE;
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} else {
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/* full checksum calculation */
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udph->check = 0;
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(*pskb)->csum = skb_checksum(*pskb, udphoff,
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(*pskb)->len - udphoff, 0);
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udph->check = csum_tcpudp_magic(cp->vaddr, cp->caddr,
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(*pskb)->len - udphoff,
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cp->protocol,
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(*pskb)->csum);
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if (udph->check == 0)
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udph->check = CSUM_MANGLED_0;
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IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
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pp->name, udph->check,
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(char*)&(udph->check) - (char*)udph);
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}
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return 1;
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}
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static int
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udp_dnat_handler(struct sk_buff **pskb,
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struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
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{
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struct udphdr *udph;
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unsigned int udphoff = ip_hdrlen(*pskb);
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/* csum_check requires unshared skb */
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if (!ip_vs_make_skb_writable(pskb, udphoff+sizeof(*udph)))
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return 0;
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if (unlikely(cp->app != NULL)) {
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/* Some checks before mangling */
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if (pp->csum_check && !pp->csum_check(*pskb, pp))
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return 0;
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/*
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* Attempt ip_vs_app call.
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* It will fix ip_vs_conn
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*/
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if (!ip_vs_app_pkt_in(cp, pskb))
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return 0;
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}
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udph = (void *)ip_hdr(*pskb) + udphoff;
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udph->dest = cp->dport;
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/*
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* Adjust UDP checksums
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*/
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if (!cp->app && (udph->check != 0)) {
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/* Only port and addr are changed, do fast csum update */
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udp_fast_csum_update(udph, cp->vaddr, cp->daddr,
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cp->vport, cp->dport);
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if ((*pskb)->ip_summed == CHECKSUM_COMPLETE)
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(*pskb)->ip_summed = CHECKSUM_NONE;
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} else {
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/* full checksum calculation */
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udph->check = 0;
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(*pskb)->csum = skb_checksum(*pskb, udphoff,
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(*pskb)->len - udphoff, 0);
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udph->check = csum_tcpudp_magic(cp->caddr, cp->daddr,
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(*pskb)->len - udphoff,
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cp->protocol,
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(*pskb)->csum);
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if (udph->check == 0)
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udph->check = CSUM_MANGLED_0;
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(*pskb)->ip_summed = CHECKSUM_UNNECESSARY;
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}
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return 1;
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}
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static int
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udp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
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{
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struct udphdr _udph, *uh;
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const unsigned int udphoff = ip_hdrlen(skb);
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uh = skb_header_pointer(skb, udphoff, sizeof(_udph), &_udph);
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if (uh == NULL)
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return 0;
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if (uh->check != 0) {
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switch (skb->ip_summed) {
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case CHECKSUM_NONE:
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skb->csum = skb_checksum(skb, udphoff,
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skb->len - udphoff, 0);
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case CHECKSUM_COMPLETE:
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if (csum_tcpudp_magic(ip_hdr(skb)->saddr,
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ip_hdr(skb)->daddr,
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skb->len - udphoff,
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ip_hdr(skb)->protocol,
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skb->csum)) {
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IP_VS_DBG_RL_PKT(0, pp, skb, 0,
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"Failed checksum for");
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return 0;
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}
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break;
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default:
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/* No need to checksum. */
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break;
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}
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}
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return 1;
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}
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/*
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* Note: the caller guarantees that only one of register_app,
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* unregister_app or app_conn_bind is called each time.
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*/
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#define UDP_APP_TAB_BITS 4
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#define UDP_APP_TAB_SIZE (1 << UDP_APP_TAB_BITS)
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#define UDP_APP_TAB_MASK (UDP_APP_TAB_SIZE - 1)
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static struct list_head udp_apps[UDP_APP_TAB_SIZE];
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static DEFINE_SPINLOCK(udp_app_lock);
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static inline __u16 udp_app_hashkey(__be16 port)
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{
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return (((__force u16)port >> UDP_APP_TAB_BITS) ^ (__force u16)port)
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& UDP_APP_TAB_MASK;
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}
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static int udp_register_app(struct ip_vs_app *inc)
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{
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struct ip_vs_app *i;
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__u16 hash;
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__be16 port = inc->port;
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int ret = 0;
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hash = udp_app_hashkey(port);
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spin_lock_bh(&udp_app_lock);
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list_for_each_entry(i, &udp_apps[hash], p_list) {
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if (i->port == port) {
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ret = -EEXIST;
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goto out;
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}
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}
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list_add(&inc->p_list, &udp_apps[hash]);
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atomic_inc(&ip_vs_protocol_udp.appcnt);
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out:
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spin_unlock_bh(&udp_app_lock);
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return ret;
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}
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static void
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udp_unregister_app(struct ip_vs_app *inc)
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{
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spin_lock_bh(&udp_app_lock);
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atomic_dec(&ip_vs_protocol_udp.appcnt);
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list_del(&inc->p_list);
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spin_unlock_bh(&udp_app_lock);
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}
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static int udp_app_conn_bind(struct ip_vs_conn *cp)
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{
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int hash;
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struct ip_vs_app *inc;
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int result = 0;
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/* Default binding: bind app only for NAT */
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if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
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return 0;
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/* Lookup application incarnations and bind the right one */
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hash = udp_app_hashkey(cp->vport);
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spin_lock(&udp_app_lock);
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list_for_each_entry(inc, &udp_apps[hash], p_list) {
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if (inc->port == cp->vport) {
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if (unlikely(!ip_vs_app_inc_get(inc)))
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break;
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spin_unlock(&udp_app_lock);
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IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->"
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"%u.%u.%u.%u:%u to app %s on port %u\n",
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__FUNCTION__,
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NIPQUAD(cp->caddr), ntohs(cp->cport),
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NIPQUAD(cp->vaddr), ntohs(cp->vport),
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inc->name, ntohs(inc->port));
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cp->app = inc;
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if (inc->init_conn)
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result = inc->init_conn(inc, cp);
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goto out;
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}
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}
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spin_unlock(&udp_app_lock);
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out:
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return result;
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}
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static int udp_timeouts[IP_VS_UDP_S_LAST+1] = {
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[IP_VS_UDP_S_NORMAL] = 5*60*HZ,
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[IP_VS_UDP_S_LAST] = 2*HZ,
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};
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static char * udp_state_name_table[IP_VS_UDP_S_LAST+1] = {
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[IP_VS_UDP_S_NORMAL] = "UDP",
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[IP_VS_UDP_S_LAST] = "BUG!",
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};
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static int
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udp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
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{
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return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_UDP_S_LAST,
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udp_state_name_table, sname, to);
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}
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static const char * udp_state_name(int state)
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{
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if (state >= IP_VS_UDP_S_LAST)
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return "ERR!";
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return udp_state_name_table[state] ? udp_state_name_table[state] : "?";
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}
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static int
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udp_state_transition(struct ip_vs_conn *cp, int direction,
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const struct sk_buff *skb,
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struct ip_vs_protocol *pp)
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{
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cp->timeout = pp->timeout_table[IP_VS_UDP_S_NORMAL];
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return 1;
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}
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static void udp_init(struct ip_vs_protocol *pp)
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{
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IP_VS_INIT_HASH_TABLE(udp_apps);
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pp->timeout_table = udp_timeouts;
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}
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static void udp_exit(struct ip_vs_protocol *pp)
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{
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}
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struct ip_vs_protocol ip_vs_protocol_udp = {
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.name = "UDP",
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.protocol = IPPROTO_UDP,
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.dont_defrag = 0,
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.init = udp_init,
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.exit = udp_exit,
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.conn_schedule = udp_conn_schedule,
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.conn_in_get = udp_conn_in_get,
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.conn_out_get = udp_conn_out_get,
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.snat_handler = udp_snat_handler,
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.dnat_handler = udp_dnat_handler,
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.csum_check = udp_csum_check,
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.state_transition = udp_state_transition,
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.state_name = udp_state_name,
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.register_app = udp_register_app,
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.unregister_app = udp_unregister_app,
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.app_conn_bind = udp_app_conn_bind,
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.debug_packet = ip_vs_tcpudp_debug_packet,
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.timeout_change = NULL,
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.set_state_timeout = udp_set_state_timeout,
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};
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