1 files changed, 563 insertions, 0 deletions

diff --git a/net/ipv4/ipvs/ip_vs_xmit.c b/net/ipv4/ipvs/ip_vs_xmit.c
new file mode 100644
index 0000000..faa6176
--- /dev/null
+++ b/net/ipv4/ipvs/ip_vs_xmit.c
@@ -0,0 +1,563 @@
+/*
+ * ip_vs_xmit.c: various packet transmitters for IPVS
+ *
+ * Version:     $Id: ip_vs_xmit.c,v 1.2 2002/11/30 01:50:35 wensong Exp $
+ *
+ * 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/kernel.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>                  /* for tcphdr */
+#include <net/tcp.h>                    /* for csum_tcpudp_magic */
+#include <net/udp.h>
+#include <net/icmp.h>                   /* for icmp_send */
+#include <net/route.h>                  /* for ip_route_output */
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+
+#include <net/ip_vs.h>
+
+
+/*
+ *      Destination cache to speed up outgoing route lookup
+ */
+static inline void
+__ip_vs_dst_set(struct ip_vs_dest *dest, u32 rtos, struct dst_entry *dst)
+{
+	struct dst_entry *old_dst;
+
+	old_dst = dest->dst_cache;
+	dest->dst_cache = dst;
+	dest->dst_rtos = rtos;
+	dst_release(old_dst);
+}
+
+static inline struct dst_entry *
+__ip_vs_dst_check(struct ip_vs_dest *dest, u32 rtos, u32 cookie)
+{
+	struct dst_entry *dst = dest->dst_cache;
+
+	if (!dst)
+		return NULL;
+	if ((dst->obsolete || rtos != dest->dst_rtos) &&
+	    dst->ops->check(dst, cookie) == NULL) {
+		dest->dst_cache = NULL;
+		dst_release(dst);
+		return NULL;
+	}
+	dst_hold(dst);
+	return dst;
+}
+
+static inline struct rtable *
+__ip_vs_get_out_rt(struct ip_vs_conn *cp, u32 rtos)
+{
+	struct rtable *rt;			/* Route to the other host */
+	struct ip_vs_dest *dest = cp->dest;
+
+	if (dest) {
+		spin_lock(&dest->dst_lock);
+		if (!(rt = (struct rtable *)
+		      __ip_vs_dst_check(dest, rtos, 0))) {
+			struct flowi fl = {
+				.oif = 0,
+				.nl_u = {
+					.ip4_u = {
+						.daddr = dest->addr,
+						.saddr = 0,
+						.tos = rtos, } },
+			};
+
+			if (ip_route_output_key(&rt, &fl)) {
+				spin_unlock(&dest->dst_lock);
+				IP_VS_DBG_RL("ip_route_output error, "
+					     "dest: %u.%u.%u.%u\n",
+					     NIPQUAD(dest->addr));
+				return NULL;
+			}
+			__ip_vs_dst_set(dest, rtos, dst_clone(&rt->u.dst));
+			IP_VS_DBG(10, "new dst %u.%u.%u.%u, refcnt=%d, rtos=%X\n",
+				  NIPQUAD(dest->addr),
+				  atomic_read(&rt->u.dst.__refcnt), rtos);
+		}
+		spin_unlock(&dest->dst_lock);
+	} else {
+		struct flowi fl = {
+			.oif = 0,
+			.nl_u = {
+				.ip4_u = {
+					.daddr = cp->daddr,
+					.saddr = 0,
+					.tos = rtos, } },
+		};
+
+		if (ip_route_output_key(&rt, &fl)) {
+			IP_VS_DBG_RL("ip_route_output error, dest: "
+				     "%u.%u.%u.%u\n", NIPQUAD(cp->daddr));
+			return NULL;
+		}
+	}
+
+	return rt;
+}
+
+
+/*
+ *	Release dest->dst_cache before a dest is removed
+ */
+void
+ip_vs_dst_reset(struct ip_vs_dest *dest)
+{
+	struct dst_entry *old_dst;
+
+	old_dst = dest->dst_cache;
+	dest->dst_cache = NULL;
+	dst_release(old_dst);
+}
+
+#define IP_VS_XMIT(skb, rt)				\
+do {							\
+	nf_reset_debug(skb);				\
+	(skb)->nfcache |= NFC_IPVS_PROPERTY;		\
+	(skb)->ip_summed = CHECKSUM_NONE;		\
+	NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, (skb), NULL,	\
+		(rt)->u.dst.dev, dst_output);		\
+} while (0)
+
+
+/*
+ *      NULL transmitter (do nothing except return NF_ACCEPT)
+ */
+int
+ip_vs_null_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
+		struct ip_vs_protocol *pp)
+{
+	/* we do not touch skb and do not need pskb ptr */
+	return NF_ACCEPT;
+}
+
+
+/*
+ *      Bypass transmitter
+ *      Let packets bypass the destination when the destination is not
+ *      available, it may be only used in transparent cache cluster.
+ */
+int
+ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
+		  struct ip_vs_protocol *pp)
+{
+	struct rtable *rt;			/* Route to the other host */
+	struct iphdr  *iph = skb->nh.iph;
+	u8     tos = iph->tos;
+	int    mtu;
+	struct flowi fl = {
+		.oif = 0,
+		.nl_u = {
+			.ip4_u = {
+				.daddr = iph->daddr,
+				.saddr = 0,
+				.tos = RT_TOS(tos), } },
+	};
+
+	EnterFunction(10);
+
+	if (ip_route_output_key(&rt, &fl)) {
+		IP_VS_DBG_RL("ip_vs_bypass_xmit(): ip_route_output error, "
+			     "dest: %u.%u.%u.%u\n", NIPQUAD(iph->daddr));
+		goto tx_error_icmp;
+	}
+
+	/* MTU checking */
+	mtu = dst_mtu(&rt->u.dst);
+	if ((skb->len > mtu) && (iph->frag_off&__constant_htons(IP_DF))) {
+		ip_rt_put(rt);
+		icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
+		IP_VS_DBG_RL("ip_vs_bypass_xmit(): frag needed\n");
+		goto tx_error;
+	}
+
+	/*
+	 * Call ip_send_check because we are not sure it is called
+	 * after ip_defrag. Is copy-on-write needed?
+	 */
+	if (unlikely((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)) {
+		ip_rt_put(rt);
+		return NF_STOLEN;
+	}
+	ip_send_check(skb->nh.iph);
+
+	/* drop old route */
+	dst_release(skb->dst);
+	skb->dst = &rt->u.dst;
+
+	/* Another hack: avoid icmp_send in ip_fragment */
+	skb->local_df = 1;
+
+	IP_VS_XMIT(skb, rt);
+
+	LeaveFunction(10);
+	return NF_STOLEN;
+
+ tx_error_icmp:
+	dst_link_failure(skb);
+ tx_error:
+	kfree_skb(skb);
+	LeaveFunction(10);
+	return NF_STOLEN;
+}
+
+
+/*
+ *      NAT transmitter (only for outside-to-inside nat forwarding)
+ *      Not used for related ICMP
+ */
+int
+ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
+	       struct ip_vs_protocol *pp)
+{
+	struct rtable *rt;		/* Route to the other host */
+	int mtu;
+	struct iphdr *iph = skb->nh.iph;
+
+	EnterFunction(10);
+
+	/* check if it is a connection of no-client-port */
+	if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
+		__u16 _pt, *p;
+		p = skb_header_pointer(skb, iph->ihl*4, sizeof(_pt), &_pt);
+		if (p == NULL)
+			goto tx_error;
+		ip_vs_conn_fill_cport(cp, *p);
+		IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
+	}
+
+	if (!(rt = __ip_vs_get_out_rt(cp, RT_TOS(iph->tos))))
+		goto tx_error_icmp;
+
+	/* MTU checking */
+	mtu = dst_mtu(&rt->u.dst);
+	if ((skb->len > mtu) && (iph->frag_off&__constant_htons(IP_DF))) {
+		ip_rt_put(rt);
+		icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
+		IP_VS_DBG_RL_PKT(0, pp, skb, 0, "ip_vs_nat_xmit(): frag needed for");
+		goto tx_error;
+	}
+
+	/* copy-on-write the packet before mangling it */
+	if (!ip_vs_make_skb_writable(&skb, sizeof(struct iphdr)))
+		goto tx_error_put;
+
+	if (skb_cow(skb, rt->u.dst.dev->hard_header_len))
+		goto tx_error_put;
+
+	/* drop old route */
+	dst_release(skb->dst);
+	skb->dst = &rt->u.dst;
+
+	/* mangle the packet */
+	if (pp->dnat_handler && !pp->dnat_handler(&skb, pp, cp))
+		goto tx_error;
+	skb->nh.iph->daddr = cp->daddr;
+	ip_send_check(skb->nh.iph);
+
+	IP_VS_DBG_PKT(10, pp, skb, 0, "After DNAT");
+
+	/* FIXME: when application helper enlarges the packet and the length
+	   is larger than the MTU of outgoing device, there will be still
+	   MTU problem. */
+
+	/* Another hack: avoid icmp_send in ip_fragment */
+	skb->local_df = 1;
+
+	IP_VS_XMIT(skb, rt);
+
+	LeaveFunction(10);
+	return NF_STOLEN;
+
+  tx_error_icmp:
+	dst_link_failure(skb);
+  tx_error:
+	LeaveFunction(10);
+	kfree_skb(skb);
+	return NF_STOLEN;
+  tx_error_put:
+	ip_rt_put(rt);
+	goto tx_error;
+}
+
+
+/*
+ *   IP Tunneling transmitter
+ *
+ *   This function encapsulates the packet in a new IP packet, its
+ *   destination will be set to cp->daddr. Most code of this function
+ *   is taken from ipip.c.
+ *
+ *   It is used in VS/TUN cluster. The load balancer selects a real
+ *   server from a cluster based on a scheduling algorithm,
+ *   encapsulates the request packet and forwards it to the selected
+ *   server. For example, all real servers are configured with
+ *   "ifconfig tunl0 <Virtual IP Address> up". When the server receives
+ *   the encapsulated packet, it will decapsulate the packet, processe
+ *   the request and return the response packets directly to the client
+ *   without passing the load balancer. This can greatly increase the
+ *   scalability of virtual server.
+ *
+ *   Used for ANY protocol
+ */
+int
+ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
+		  struct ip_vs_protocol *pp)
+{
+	struct rtable *rt;			/* Route to the other host */
+	struct net_device *tdev;		/* Device to other host */
+	struct iphdr  *old_iph = skb->nh.iph;
+	u8     tos = old_iph->tos;
+	u16    df = old_iph->frag_off;
+	struct iphdr  *iph;			/* Our new IP header */
+	int    max_headroom;			/* The extra header space needed */
+	int    mtu;
+
+	EnterFunction(10);
+
+	if (skb->protocol != __constant_htons(ETH_P_IP)) {
+		IP_VS_DBG_RL("ip_vs_tunnel_xmit(): protocol error, "
+			     "ETH_P_IP: %d, skb protocol: %d\n",
+			     __constant_htons(ETH_P_IP), skb->protocol);
+		goto tx_error;
+	}
+
+	if (!(rt = __ip_vs_get_out_rt(cp, RT_TOS(tos))))
+		goto tx_error_icmp;
+
+	tdev = rt->u.dst.dev;
+
+	mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
+	if (mtu < 68) {
+		ip_rt_put(rt);
+		IP_VS_DBG_RL("ip_vs_tunnel_xmit(): mtu less than 68\n");
+		goto tx_error;
+	}
+	if (skb->dst)
+		skb->dst->ops->update_pmtu(skb->dst, mtu);
+
+	df |= (old_iph->frag_off&__constant_htons(IP_DF));
+
+	if ((old_iph->frag_off&__constant_htons(IP_DF))
+	    && mtu < ntohs(old_iph->tot_len)) {
+		icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
+		ip_rt_put(rt);
+		IP_VS_DBG_RL("ip_vs_tunnel_xmit(): frag needed\n");
+		goto tx_error;
+	}
+
+	/*
+	 * Okay, now see if we can stuff it in the buffer as-is.
+	 */
+	max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);
+
+	if (skb_headroom(skb) < max_headroom
+	    || skb_cloned(skb) || skb_shared(skb)) {
+		struct sk_buff *new_skb =
+			skb_realloc_headroom(skb, max_headroom);
+		if (!new_skb) {
+			ip_rt_put(rt);
+			kfree_skb(skb);
+			IP_VS_ERR_RL("ip_vs_tunnel_xmit(): no memory\n");
+			return NF_STOLEN;
+		}
+		kfree_skb(skb);
+		skb = new_skb;
+		old_iph = skb->nh.iph;
+	}
+
+	skb->h.raw = (void *) old_iph;
+
+	/* fix old IP header checksum */
+	ip_send_check(old_iph);
+
+	skb->nh.raw = skb_push(skb, sizeof(struct iphdr));
+	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+
+	/* drop old route */
+	dst_release(skb->dst);
+	skb->dst = &rt->u.dst;
+
+	/*
+	 *	Push down and install the IPIP header.
+	 */
+	iph			=	skb->nh.iph;
+	iph->version		=	4;
+	iph->ihl		=	sizeof(struct iphdr)>>2;
+	iph->frag_off		=	df;
+	iph->protocol		=	IPPROTO_IPIP;
+	iph->tos		=	tos;
+	iph->daddr		=	rt->rt_dst;
+	iph->saddr		=	rt->rt_src;
+	iph->ttl		=	old_iph->ttl;
+	iph->tot_len		=	htons(skb->len);
+	ip_select_ident(iph, &rt->u.dst, NULL);
+	ip_send_check(iph);
+
+	/* Another hack: avoid icmp_send in ip_fragment */
+	skb->local_df = 1;
+
+	IP_VS_XMIT(skb, rt);
+
+	LeaveFunction(10);
+
+	return NF_STOLEN;
+
+  tx_error_icmp:
+	dst_link_failure(skb);
+  tx_error:
+	kfree_skb(skb);
+	LeaveFunction(10);
+	return NF_STOLEN;
+}
+
+
+/*
+ *      Direct Routing transmitter
+ *      Used for ANY protocol
+ */
+int
+ip_vs_dr_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
+	      struct ip_vs_protocol *pp)
+{
+	struct rtable *rt;			/* Route to the other host */
+	struct iphdr  *iph = skb->nh.iph;
+	int    mtu;
+
+	EnterFunction(10);
+
+	if (!(rt = __ip_vs_get_out_rt(cp, RT_TOS(iph->tos))))
+		goto tx_error_icmp;
+
+	/* MTU checking */
+	mtu = dst_mtu(&rt->u.dst);
+	if ((iph->frag_off&__constant_htons(IP_DF)) && skb->len > mtu) {
+		icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
+		ip_rt_put(rt);
+		IP_VS_DBG_RL("ip_vs_dr_xmit(): frag needed\n");
+		goto tx_error;
+	}
+
+	/*
+	 * Call ip_send_check because we are not sure it is called
+	 * after ip_defrag. Is copy-on-write needed?
+	 */
+	if (unlikely((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)) {
+		ip_rt_put(rt);
+		return NF_STOLEN;
+	}
+	ip_send_check(skb->nh.iph);
+
+	/* drop old route */
+	dst_release(skb->dst);
+	skb->dst = &rt->u.dst;
+
+	/* Another hack: avoid icmp_send in ip_fragment */
+	skb->local_df = 1;
+
+	IP_VS_XMIT(skb, rt);
+
+	LeaveFunction(10);
+	return NF_STOLEN;
+
+  tx_error_icmp:
+	dst_link_failure(skb);
+  tx_error:
+	kfree_skb(skb);
+	LeaveFunction(10);
+	return NF_STOLEN;
+}
+
+
+/*
+ *	ICMP packet transmitter
+ *	called by the ip_vs_in_icmp
+ */
+int
+ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
+		struct ip_vs_protocol *pp, int offset)
+{
+	struct rtable	*rt;	/* Route to the other host */
+	int mtu;
+	int rc;
+
+	EnterFunction(10);
+
+	/* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
+	   forwarded directly here, because there is no need to
+	   translate address/port back */
+	if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
+		if (cp->packet_xmit)
+			rc = cp->packet_xmit(skb, cp, pp);
+		else
+			rc = NF_ACCEPT;
+		/* do not touch skb anymore */
+		atomic_inc(&cp->in_pkts);
+		__ip_vs_conn_put(cp);
+		goto out;
+	}
+
+	/*
+	 * mangle and send the packet here (only for VS/NAT)
+	 */
+
+	if (!(rt = __ip_vs_get_out_rt(cp, RT_TOS(skb->nh.iph->tos))))
+		goto tx_error_icmp;
+
+	/* MTU checking */
+	mtu = dst_mtu(&rt->u.dst);
+	if ((skb->len > mtu) && (skb->nh.iph->frag_off&__constant_htons(IP_DF))) {
+		ip_rt_put(rt);
+		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
+		IP_VS_DBG_RL("ip_vs_in_icmp(): frag needed\n");
+		goto tx_error;
+	}
+
+	/* copy-on-write the packet before mangling it */
+	if (!ip_vs_make_skb_writable(&skb, offset))
+		goto tx_error_put;
+
+	if (skb_cow(skb, rt->u.dst.dev->hard_header_len))
+		goto tx_error_put;
+
+	/* drop the old route when skb is not shared */
+	dst_release(skb->dst);
+	skb->dst = &rt->u.dst;
+
+	ip_vs_nat_icmp(skb, pp, cp, 0);
+
+	/* Another hack: avoid icmp_send in ip_fragment */
+	skb->local_df = 1;
+
+	IP_VS_XMIT(skb, rt);
+
+	rc = NF_STOLEN;
+	goto out;
+
+  tx_error_icmp:
+	dst_link_failure(skb);
+  tx_error:
+	dev_kfree_skb(skb);
+	rc = NF_STOLEN;
+  out:
+	LeaveFunction(10);
+	return rc;
+  tx_error_put:
+	ip_rt_put(rt);
+	goto tx_error;
+}