IPVS: Add/adjust Netfilter hook functions and helpers for v6

Add Netfilter hook functions or modify existing ones, if possible, to
process IPv6 packets. Some support functions are also added/modified for
this. ip_vs_nat_icmp_v6() was already added in the patch that added the v6
xmit functions, as it is called from one of them.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 329 insertions, 36 deletions

diff --git a/net/ipv4/ipvs/ip_vs_core.c b/net/ipv4/ipvs/ip_vs_core.c
index 8bfd7c2f0ebe..035a511e12f7 100644
--- a/net/ipv4/ipvs/ip_vs_core.c
+++ b/net/ipv4/ipvs/ip_vs_core.c
@@ -39,6 +39,11 @@
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv4.h>
 
+#ifdef CONFIG_IP_VS_IPV6
+#include <net/ipv6.h>
+#include <linux/netfilter_ipv6.h>
+#endif
+
 #include <net/ip_vs.h>
 
 
@@ -60,6 +65,7 @@ EXPORT_SYMBOL(ip_vs_get_debug_level);
 
 /* ID used in ICMP lookups */
 #define icmp_id(icmph)          (((icmph)->un).echo.id)
+#define icmpv6_id(icmph)        (icmph->icmp6_dataun.u_echo.identifier)
 
 const char *ip_vs_proto_name(unsigned proto)
 {
@@ -74,6 +80,10 @@ const char *ip_vs_proto_name(unsigned proto)
                 return "TCP";
         case IPPROTO_ICMP:
                 return "ICMP";
+#ifdef CONFIG_IP_VS_IPV6
+        case IPPROTO_ICMPV6:
+                return "ICMPv6";
+#endif
         default:
                 sprintf(buf, "IP_%d", proto);
                 return buf;
@@ -425,7 +435,8 @@ int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
 {
         __be16 _ports[2], *pptr;
         struct ip_vs_iphdr iph;
-        ip_vs_fill_iphdr(AF_INET, skb_network_header(skb), &iph);
+        int unicast;
+        ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
 
         pptr = skb_header_pointer(skb, iph.len, sizeof(_ports), _ports);
         if (pptr == NULL) {
@@ -433,11 +444,17 @@ int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
                 return NF_DROP;
         }
 
+#ifdef CONFIG_IP_VS_IPV6
+        if (svc->af == AF_INET6)
+                unicast = ipv6_addr_type(&iph.daddr.in6) & IPV6_ADDR_UNICAST;
+        else
+#endif
+                unicast = (inet_addr_type(&init_net, iph.daddr.ip) == RTN_UNICAST);
+
         /* if it is fwmark-based service, the cache_bypass sysctl is up
-           and the destination is RTN_UNICAST (and not local), then create
+           and the destination is a non-local unicast, then create
            a cache_bypass connection entry */
-        if (sysctl_ip_vs_cache_bypass && svc->fwmark
-            && (inet_addr_type(&init_net, iph.daddr.ip) == RTN_UNICAST)) {
+        if (sysctl_ip_vs_cache_bypass && svc->fwmark && unicast) {
                 int ret, cs;
                 struct ip_vs_conn *cp;
 
@@ -445,7 +462,7 @@ int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
 
                 /* create a new connection entry */
                 IP_VS_DBG(6, "ip_vs_leave: create a cache_bypass entry\n");
-                cp = ip_vs_conn_new(AF_INET, iph.protocol,
+                cp = ip_vs_conn_new(svc->af, iph.protocol,
                                     &iph.saddr, pptr[0],
                                     &iph.daddr, pptr[1],
                                     0, 0,
@@ -489,7 +506,14 @@ int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
          * created, the TCP RST packet cannot be sent, instead that
          * ICMP_PORT_UNREACH is sent here no matter it is TCP/UDP. --WZ
          */
-        icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
+#ifdef CONFIG_IP_VS_IPV6
+        if (svc->af == AF_INET6)
+                icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0,
+                            skb->dev);
+        else
+#endif
+                icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
+
         return NF_DROP;
 }
 
@@ -528,6 +552,14 @@ static inline int ip_vs_gather_frags(struct sk_buff *skb, u_int32_t user)
         return err;
 }
 
+#ifdef CONFIG_IP_VS_IPV6
+static inline int ip_vs_gather_frags_v6(struct sk_buff *skb, u_int32_t user)
+{
+        /* TODO IPv6: Find out what to do here for IPv6 */
+        return 0;
+}
+#endif
+
 /*
  * Packet has been made sufficiently writable in caller
  * - inout: 1=in->out, 0=out->in
@@ -727,11 +759,117 @@ static int ip_vs_out_icmp(struct sk_buff *skb, int *related)
         return verdict;
 }
 
-static inline int is_tcp_reset(const struct sk_buff *skb)
+#ifdef CONFIG_IP_VS_IPV6
+static int ip_vs_out_icmp_v6(struct sk_buff *skb, int *related)
+{
+        struct ipv6hdr *iph;
+        struct icmp6hdr _icmph, *ic;
+        struct ipv6hdr  _ciph, *cih;    /* The ip header contained
+                                           within the ICMP */
+        struct ip_vs_iphdr ciph;
+        struct ip_vs_conn *cp;
+        struct ip_vs_protocol *pp;
+        unsigned int offset, verdict;
+
+        *related = 1;
+
+        /* reassemble IP fragments */
+        if (ipv6_hdr(skb)->nexthdr == IPPROTO_FRAGMENT) {
+                if (ip_vs_gather_frags_v6(skb, IP_DEFRAG_VS_OUT))
+                        return NF_STOLEN;
+        }
+
+        iph = ipv6_hdr(skb);
+        offset = sizeof(struct ipv6hdr);
+        ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
+        if (ic == NULL)
+                return NF_DROP;
+
+        IP_VS_DBG(12, "Outgoing ICMPv6 (%d,%d) " NIP6_FMT "->" NIP6_FMT "\n",
+                  ic->icmp6_type, ntohs(icmpv6_id(ic)),
+                  NIP6(iph->saddr), NIP6(iph->daddr));
+
+        /*
+         * Work through seeing if this is for us.
+         * These checks are supposed to be in an order that means easy
+         * things are checked first to speed up processing.... however
+         * this means that some packets will manage to get a long way
+         * down this stack and then be rejected, but that's life.
+         */
+        if ((ic->icmp6_type != ICMPV6_DEST_UNREACH) &&
+            (ic->icmp6_type != ICMPV6_PKT_TOOBIG) &&
+            (ic->icmp6_type != ICMPV6_TIME_EXCEED)) {
+                *related = 0;
+                return NF_ACCEPT;
+        }
+
+        /* Now find the contained IP header */
+        offset += sizeof(_icmph);
+        cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
+        if (cih == NULL)
+                return NF_ACCEPT; /* The packet looks wrong, ignore */
+
+        pp = ip_vs_proto_get(cih->nexthdr);
+        if (!pp)
+                return NF_ACCEPT;
+
+        /* Is the embedded protocol header present? */
+        /* TODO: we don't support fragmentation at the moment anyways */
+        if (unlikely(cih->nexthdr == IPPROTO_FRAGMENT && pp->dont_defrag))
+                return NF_ACCEPT;
+
+        IP_VS_DBG_PKT(11, pp, skb, offset, "Checking outgoing ICMPv6 for");
+
+        offset += sizeof(struct ipv6hdr);
+
+        ip_vs_fill_iphdr(AF_INET6, cih, &ciph);
+        /* The embedded headers contain source and dest in reverse order */
+        cp = pp->conn_out_get(AF_INET6, skb, pp, &ciph, offset, 1);
+        if (!cp)
+                return NF_ACCEPT;
+
+        verdict = NF_DROP;
+
+        if (IP_VS_FWD_METHOD(cp) != 0) {
+                IP_VS_ERR("shouldn't reach here, because the box is on the "
+                          "half connection in the tun/dr module.\n");
+        }
+
+        /* Ensure the checksum is correct */
+        if (!skb_csum_unnecessary(skb)
+            && ip_vs_checksum_complete(skb, sizeof(struct ipv6hdr))) {
+                /* Failed checksum! */
+                IP_VS_DBG(1, "Forward ICMPv6: failed checksum from "
+                          NIP6_FMT "!\n",
+                          NIP6(iph->saddr));
+                goto out;
+        }
+
+        if (IPPROTO_TCP == cih->nexthdr || IPPROTO_UDP == cih->nexthdr)
+                offset += 2 * sizeof(__u16);
+        if (!skb_make_writable(skb, offset))
+                goto out;
+
+        ip_vs_nat_icmp_v6(skb, pp, cp, 1);
+
+        /* do the statistics and put it back */
+        ip_vs_out_stats(cp, skb);
+
+        skb->ipvs_property = 1;
+        verdict = NF_ACCEPT;
+
+out:
+        __ip_vs_conn_put(cp);
+
+        return verdict;
+}
+#endif
+
+static inline int is_tcp_reset(const struct sk_buff *skb, int nh_len)
 {
         struct tcphdr _tcph, *th;
 
-        th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
+        th = skb_header_pointer(skb, nh_len, sizeof(_tcph), &_tcph);
         if (th == NULL)
                 return 0;
         return th->rst;
@@ -750,38 +888,64 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb,
         struct ip_vs_iphdr iph;
         struct ip_vs_protocol *pp;
         struct ip_vs_conn *cp;
+        int af;
 
         EnterFunction(11);
 
+        af = (skb->protocol == __constant_htons(ETH_P_IP)) ? AF_INET : AF_INET6;
+
         if (skb->ipvs_property)
                 return NF_ACCEPT;
 
-        ip_vs_fill_iphdr(AF_INET, skb_network_header(skb), &iph);
-        if (unlikely(iph.protocol == IPPROTO_ICMP)) {
-                int related, verdict = ip_vs_out_icmp(skb, &related);
+        ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
+#ifdef CONFIG_IP_VS_IPV6
+        if (af == AF_INET6) {
+                if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
+                        int related, verdict = ip_vs_out_icmp_v6(skb, &related);
 
-                if (related)
-                        return verdict;
-                ip_vs_fill_iphdr(AF_INET, skb_network_header(skb), &iph);
-        }
+                        if (related)
+                                return verdict;
+                        ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
+                }
+        } else
+#endif
+                if (unlikely(iph.protocol == IPPROTO_ICMP)) {
+                        int related, verdict = ip_vs_out_icmp(skb, &related);
+
+                        if (related)
+                                return verdict;
+                        ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
+                }
 
         pp = ip_vs_proto_get(iph.protocol);
         if (unlikely(!pp))
                 return NF_ACCEPT;
 
         /* reassemble IP fragments */
-        if (unlikely(ip_hdr(skb)->frag_off & htons(IP_MF|IP_OFFSET) &&
-                     !pp->dont_defrag)) {
-                if (ip_vs_gather_frags(skb, IP_DEFRAG_VS_OUT))
-                        return NF_STOLEN;
+#ifdef CONFIG_IP_VS_IPV6
+        if (af == AF_INET6) {
+                if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
+                        int related, verdict = ip_vs_out_icmp_v6(skb, &related);
 
-                ip_vs_fill_iphdr(AF_INET, skb_network_header(skb), &iph);
-        }
+                        if (related)
+                                return verdict;
+
+                        ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
+                }
+        } else
+#endif
+                if (unlikely(ip_hdr(skb)->frag_off & htons(IP_MF|IP_OFFSET) &&
+                             !pp->dont_defrag)) {
+                        if (ip_vs_gather_frags(skb, IP_DEFRAG_VS_OUT))
+                                return NF_STOLEN;
+
+                        ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
+                }
 
         /*
          * Check if the packet belongs to an existing entry
          */
-        cp = pp->conn_out_get(AF_INET, skb, pp, &iph, iph.len, 0);
+        cp = pp->conn_out_get(af, skb, pp, &iph, iph.len, 0);
 
         if (unlikely(!cp)) {
                 if (sysctl_ip_vs_nat_icmp_send &&
@@ -794,16 +958,26 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb,
                         if (pptr == NULL)
                                 return NF_ACCEPT;       /* Not for me */
                         if (ip_vs_lookup_real_service(iph.protocol,
-                                                      iph.saddr.ip, pptr[0])) {
+                                                      iph.saddr.ip,
+                                                      pptr[0])) {
                                 /*
                                  * Notify the real server: there is no
                                  * existing entry if it is not RST
                                  * packet or not TCP packet.
                                  */
                                 if (iph.protocol != IPPROTO_TCP
-                                    || !is_tcp_reset(skb)) {
-                                        icmp_send(skb,ICMP_DEST_UNREACH,
-                                                  ICMP_PORT_UNREACH, 0);
+                                    || !is_tcp_reset(skb, iph.len)) {
+#ifdef CONFIG_IP_VS_IPV6
+                                        if (af == AF_INET6)
+                                                icmpv6_send(skb,
+                                                            ICMPV6_DEST_UNREACH,
+                                                            ICMPV6_PORT_UNREACH,
+                                                            0, skb->dev);
+                                        else
+#endif
+                                                icmp_send(skb,
+                                                          ICMP_DEST_UNREACH,
+                                                          ICMP_PORT_UNREACH, 0);
                                         return NF_DROP;
                                 }
                         }
@@ -821,8 +995,16 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb,
         /* mangle the packet */
         if (pp->snat_handler && !pp->snat_handler(skb, pp, cp))
                 goto drop;
-        ip_hdr(skb)->saddr = cp->vaddr.ip;
-        ip_send_check(ip_hdr(skb));
+
+#ifdef CONFIG_IP_VS_IPV6
+        if (af == AF_INET6)
+                ipv6_hdr(skb)->saddr = cp->vaddr.in6;
+        else
+#endif
+        {
+                ip_hdr(skb)->saddr = cp->vaddr.ip;
+                ip_send_check(ip_hdr(skb));
+        }
 
         /* For policy routing, packets originating from this
          * machine itself may be routed differently to packets
@@ -830,8 +1012,14 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb,
          * if it came from this machine itself.  So re-compute
          * the routing information.
          */
-        if (ip_route_me_harder(skb, RTN_LOCAL) != 0)
-                goto drop;
+#ifdef CONFIG_IP_VS_IPV6
+        if (af == AF_INET6) {
+                if (ip6_route_me_harder(skb) != 0)
+                        goto drop;
+        } else
+#endif
+                if (ip_route_me_harder(skb, RTN_LOCAL) != 0)
+                        goto drop;
 
         IP_VS_DBG_PKT(10, pp, skb, 0, "After SNAT");
 
@@ -949,6 +1137,94 @@ ip_vs_in_icmp(struct sk_buff *skb, int *related, unsigned int hooknum)
         return verdict;
 }
 
+#ifdef CONFIG_IP_VS_IPV6
+static int
+ip_vs_in_icmp_v6(struct sk_buff *skb, int *related, unsigned int hooknum)
+{
+        struct ipv6hdr *iph;
+        struct icmp6hdr _icmph, *ic;
+        struct ipv6hdr  _ciph, *cih;    /* The ip header contained
+                                           within the ICMP */
+        struct ip_vs_iphdr ciph;
+        struct ip_vs_conn *cp;
+        struct ip_vs_protocol *pp;
+        unsigned int offset, verdict;
+
+        *related = 1;
+
+        /* reassemble IP fragments */
+        if (ipv6_hdr(skb)->nexthdr == IPPROTO_FRAGMENT) {
+                if (ip_vs_gather_frags_v6(skb, hooknum == NF_INET_LOCAL_IN ?
+                                               IP_DEFRAG_VS_IN :
+                                               IP_DEFRAG_VS_FWD))
+                        return NF_STOLEN;
+        }
+
+        iph = ipv6_hdr(skb);
+        offset = sizeof(struct ipv6hdr);
+        ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
+        if (ic == NULL)
+                return NF_DROP;
+
+        IP_VS_DBG(12, "Incoming ICMPv6 (%d,%d) " NIP6_FMT "->" NIP6_FMT "\n",
+                  ic->icmp6_type, ntohs(icmpv6_id(ic)),
+                  NIP6(iph->saddr), NIP6(iph->daddr));
+
+        /*
+         * Work through seeing if this is for us.
+         * These checks are supposed to be in an order that means easy
+         * things are checked first to speed up processing.... however
+         * this means that some packets will manage to get a long way
+         * down this stack and then be rejected, but that's life.
+         */
+        if ((ic->icmp6_type != ICMPV6_DEST_UNREACH) &&
+            (ic->icmp6_type != ICMPV6_PKT_TOOBIG) &&
+            (ic->icmp6_type != ICMPV6_TIME_EXCEED)) {
+                *related = 0;
+                return NF_ACCEPT;
+        }
+
+        /* Now find the contained IP header */
+        offset += sizeof(_icmph);
+        cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
+        if (cih == NULL)
+                return NF_ACCEPT; /* The packet looks wrong, ignore */
+
+        pp = ip_vs_proto_get(cih->nexthdr);
+        if (!pp)
+                return NF_ACCEPT;
+
+        /* Is the embedded protocol header present? */
+        /* TODO: we don't support fragmentation at the moment anyways */
+        if (unlikely(cih->nexthdr == IPPROTO_FRAGMENT && pp->dont_defrag))
+                return NF_ACCEPT;
+
+        IP_VS_DBG_PKT(11, pp, skb, offset, "Checking incoming ICMPv6 for");
+
+        offset += sizeof(struct ipv6hdr);
+
+        ip_vs_fill_iphdr(AF_INET6, cih, &ciph);
+        /* The embedded headers contain source and dest in reverse order */
+        cp = pp->conn_in_get(AF_INET6, skb, pp, &ciph, offset, 1);
+        if (!cp)
+                return NF_ACCEPT;
+
+        verdict = NF_DROP;
+
+        /* do the statistics and put it back */
+        ip_vs_in_stats(cp, skb);
+        if (IPPROTO_TCP == cih->nexthdr || IPPROTO_UDP == cih->nexthdr)
+                offset += 2 * sizeof(__u16);
+        verdict = ip_vs_icmp_xmit_v6(skb, cp, pp, offset);
+        /* do not touch skb anymore */
+
+        __ip_vs_conn_put(cp);
+
+        return verdict;
+}
+#endif
+
+
 /*
  *      Check if it's for virtual services, look it up,
  *      and send it on its way...
@@ -961,9 +1237,11 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb,
         struct ip_vs_iphdr iph;
         struct ip_vs_protocol *pp;
         struct ip_vs_conn *cp;
-        int ret, restart;
+        int ret, restart, af;
+
+        af = (skb->protocol == __constant_htons(ETH_P_IP)) ? AF_INET : AF_INET6;
 
-        ip_vs_fill_iphdr(AF_INET, skb_network_header(skb), &iph);
+        ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
 
         /*
          *      Big tappo: only PACKET_HOST (neither loopback nor mcasts)
@@ -974,7 +1252,7 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb,
                 IP_VS_DBG_BUF(12, "packet type=%d proto=%d daddr=%s ignored\n",
                               skb->pkt_type,
                               iph.protocol,
-                              IP_VS_DBG_ADDR(AF_INET, &iph.daddr));
+                              IP_VS_DBG_ADDR(af, &iph.daddr));
                 return NF_ACCEPT;
         }
 
@@ -983,7 +1261,7 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb,
 
                 if (related)
                         return verdict;
-                ip_vs_fill_iphdr(AF_INET, skb_network_header(skb), &iph);
+                ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
         }
 
         /* Protocol supported? */
@@ -994,12 +1272,12 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb,
         /*
          * Check if the packet belongs to an existing connection entry
          */
-        cp = pp->conn_in_get(AF_INET, skb, pp, &iph, iph.len, 0);
+        cp = pp->conn_in_get(af, skb, pp, &iph, iph.len, 0);
 
         if (unlikely(!cp)) {
                 int v;
 
-                if (!pp->conn_schedule(AF_INET, skb, pp, &v, &cp))
+                if (!pp->conn_schedule(af, skb, pp, &v, &cp))
                         return v;
         }
 
@@ -1082,6 +1360,21 @@ ip_vs_forward_icmp(unsigned int hooknum, struct sk_buff *skb,
         return ip_vs_in_icmp(skb, &r, hooknum);
 }
 
+#ifdef CONFIG_IP_VS_IPV6
+static unsigned int
+ip_vs_forward_icmp_v6(unsigned int hooknum, struct sk_buff *skb,
+                      const struct net_device *in, const struct net_device *out,
+                      int (*okfn)(struct sk_buff *))
+{
+        int r;
+
+        if (ipv6_hdr(skb)->nexthdr != IPPROTO_ICMPV6)
+                return NF_ACCEPT;
+
+        return ip_vs_in_icmp_v6(skb, &r, hooknum);
+}
+#endif
+
 
 static struct nf_hook_ops ip_vs_ops[] __read_mostly = {
         /* After packet filtering, forward packet through VS/DR, VS/TUN,