1 files changed, 533 insertions, 0 deletions

diff --git a/net/netfilter/ipvs/ip_vs_proto_udp.c b/net/netfilter/ipvs/ip_vs_proto_udp.c
new file mode 100644
index 0000000..6eb6039
--- /dev/null
+++ b/net/netfilter/ipvs/ip_vs_proto_udp.c
@@ -0,0 +1,533 @@
+/*
+ * 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:
+ *
+ */
+
+#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,
+					htonl(oldlen),
+					htonl(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,
+					htonl(oldlen),
+					htonl(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 char * 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,
+};