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authorJesper Dangaard Brouer <brouer@redhat.com>2012-09-26 16:06:41 +0400
committerSimon Horman <horms@verge.net.au>2012-09-28 06:34:15 +0400
commit63dca2c0b0e7a92cb39d1b1ecefa32ffda201975 (patch)
tree4998cbf50a15ab5a939dc8cd722c668f601ba3cc /include/net/ip_vs.h
parenta638e51437f5efd00c4579df56cfd4d497ed51a8 (diff)
downloadlinux-63dca2c0b0e7a92cb39d1b1ecefa32ffda201975.tar.xz
ipvs: Fix faulty IPv6 extension header handling in IPVS
IPv6 packets can contain extension headers, thus its wrong to assume that the transport/upper-layer header, starts right after (struct ipv6hdr) the IPv6 header. IPVS uses this false assumption, and will write SNAT & DNAT modifications at a fixed pos which will corrupt the message. To fix this, proper header position must be found before modifying packets. Introducing ip_vs_fill_iph_skb(), which uses ipv6_find_hdr() to skip the exthdrs. It finds (1) the transport header offset, (2) the protocol, and (3) detects if the packet is a fragment. Note, that fragments in IPv6 is represented via an exthdr. Thus, this is detected while skipping through the exthdrs. This patch depends on commit 84018f55a: "netfilter: ip6_tables: add flags parameter to ipv6_find_hdr()" This also adds a dependency to ip6_tables. Originally based on patch from: Hans Schillstrom kABI notes: Changing struct ip_vs_iphdr is a potential minor kABI breaker, because external modules can be compiled with another version of this struct. This should not matter, as they would most-likely be using a compiled-in version of ip_vs_fill_iphdr(). When recompiled, they will notice ip_vs_fill_iphdr() no longer exists, and they have to used ip_vs_fill_iph_skb() instead. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Simon Horman <horms@verge.net.au>
Diffstat (limited to 'include/net/ip_vs.h')
-rw-r--r--include/net/ip_vs.h72
1 files changed, 62 insertions, 10 deletions
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index c8b2bdbaf91b..29265bf4153e 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -22,6 +22,9 @@
#include <linux/ip.h>
#include <linux/ipv6.h> /* for struct ipv6hdr */
#include <net/ipv6.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#endif
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
#include <net/netfilter/nf_conntrack.h>
#endif
@@ -103,30 +106,79 @@ static inline struct net *seq_file_single_net(struct seq_file *seq)
/* Connections' size value needed by ip_vs_ctl.c */
extern int ip_vs_conn_tab_size;
-
struct ip_vs_iphdr {
- int len;
- __u8 protocol;
+ __u32 len; /* IPv4 simply where L4 starts
+ IPv6 where L4 Transport Header starts */
+ __u16 fragoffs; /* IPv6 fragment offset, 0 if first frag (or not frag)*/
+ __s16 protocol;
+ __s32 flags;
union nf_inet_addr saddr;
union nf_inet_addr daddr;
};
static inline void
-ip_vs_fill_iphdr(int af, const void *nh, struct ip_vs_iphdr *iphdr)
+ip_vs_fill_ip4hdr(const void *nh, struct ip_vs_iphdr *iphdr)
+{
+ const struct iphdr *iph = nh;
+
+ iphdr->len = iph->ihl * 4;
+ iphdr->fragoffs = 0;
+ iphdr->protocol = iph->protocol;
+ iphdr->saddr.ip = iph->saddr;
+ iphdr->daddr.ip = iph->daddr;
+}
+
+/* This function handles filling *ip_vs_iphdr, both for IPv4 and IPv6.
+ * IPv6 requires some extra work, as finding proper header position,
+ * depend on the IPv6 extension headers.
+ */
+static inline void
+ip_vs_fill_iph_skb(int af, const struct sk_buff *skb, struct ip_vs_iphdr *iphdr)
{
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6) {
- const struct ipv6hdr *iph = nh;
- iphdr->len = sizeof(struct ipv6hdr);
- iphdr->protocol = iph->nexthdr;
+ const struct ipv6hdr *iph =
+ (struct ipv6hdr *)skb_network_header(skb);
iphdr->saddr.in6 = iph->saddr;
iphdr->daddr.in6 = iph->daddr;
+ /* ipv6_find_hdr() updates len, flags */
+ iphdr->len = 0;
+ iphdr->flags = 0;
+ iphdr->protocol = ipv6_find_hdr(skb, &iphdr->len, -1,
+ &iphdr->fragoffs,
+ &iphdr->flags);
} else
#endif
{
- const struct iphdr *iph = nh;
- iphdr->len = iph->ihl * 4;
- iphdr->protocol = iph->protocol;
+ const struct iphdr *iph =
+ (struct iphdr *)skb_network_header(skb);
+ iphdr->len = iph->ihl * 4;
+ iphdr->fragoffs = 0;
+ iphdr->protocol = iph->protocol;
+ iphdr->saddr.ip = iph->saddr;
+ iphdr->daddr.ip = iph->daddr;
+ }
+}
+
+/* This function is a faster version of ip_vs_fill_iph_skb().
+ * Where we only populate {s,d}addr (and avoid calling ipv6_find_hdr()).
+ * This is used by the some of the ip_vs_*_schedule() functions.
+ * (Mostly done to avoid ABI breakage of external schedulers)
+ */
+static inline void
+ip_vs_fill_iph_addr_only(int af, const struct sk_buff *skb,
+ struct ip_vs_iphdr *iphdr)
+{
+#ifdef CONFIG_IP_VS_IPV6
+ if (af == AF_INET6) {
+ const struct ipv6hdr *iph =
+ (struct ipv6hdr *)skb_network_header(skb);
+ iphdr->saddr.in6 = iph->saddr;
+ iphdr->daddr.in6 = iph->daddr;
+ } else {
+#endif
+ const struct iphdr *iph =
+ (struct iphdr *)skb_network_header(skb);
iphdr->saddr.ip = iph->saddr;
iphdr->daddr.ip = iph->daddr;
}