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Diffstat (limited to 'net/ipv4/ipvs/ip_vs_xmit.c')
-rw-r--r--net/ipv4/ipvs/ip_vs_xmit.c563
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 00000000000..faa6176bbeb
--- /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;
+}
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