compat: Backport IPv4 reassembly.

[cascardo/ovs.git] / datapath / linux / compat / include / net / ip.h

diff --git a/datapath/linux/compat/include/net/ip.h b/datapath/linux/compat/include/net/ip.h
index a9401a7..63a3f09 100644 (file)
--- a/datapath/linux/compat/include/net/ip.h
+++ b/datapath/linux/compat/include/net/ip.h
@@ -3,6 +3,7 @@
 
 #include_next <net/ip.h>
 
+#include <net/route.h>
 #include <linux/version.h>
 
 #ifndef HAVE_IP_IS_FRAGMENT
@@ -22,4 +23,109 @@ static inline void rpl_inet_get_local_port_range(struct net *net, int *low,
 
 #endif
 
+#ifndef IPSKB_FRAG_PMTU
+#define IPSKB_FRAG_PMTU                BIT(6)
+#endif
+
+/* IPv4 datagram length is stored into 16bit field (tot_len) */
+#ifndef IP_MAX_MTU
+#define IP_MAX_MTU     0xFFFFU
+#endif
+
+#ifndef HAVE_IP_SKB_DST_MTU
+static inline bool rpl_ip_sk_use_pmtu(const struct sock *sk)
+{
+       return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
+}
+#define ip_sk_use_pmtu rpl_ip_sk_use_pmtu
+
+static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
+                                                   bool forwarding)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,14,0)
+       struct net *net = dev_net(dst->dev);
+
+       if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
+           dst_metric_locked(dst, RTAX_MTU) ||
+           !forwarding)
+               return dst_mtu(dst);
+#endif
+
+       return min(dst->dev->mtu, IP_MAX_MTU);
+}
+
+static inline unsigned int rpl_ip_skb_dst_mtu(const struct sk_buff *skb)
+{
+       if (!skb->sk || ip_sk_use_pmtu(skb->sk)) {
+               bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
+               return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
+       } else {
+               return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU);
+       }
+}
+#define ip_skb_dst_mtu rpl_ip_skb_dst_mtu
+#endif /* HAVE_IP_SKB_DST_MTU */
+
+#ifdef HAVE_IP_FRAGMENT_TAKES_SOCK
+#define OVS_VPORT_OUTPUT_PARAMS struct sock *sock, struct sk_buff *skb
+#else
+#define OVS_VPORT_OUTPUT_PARAMS struct sk_buff *skb
+#endif
+
+#ifdef OVS_FRAGMENT_BACKPORT
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,2,0)
+static inline bool ip_defrag_user_in_between(u32 user,
+                                            enum ip_defrag_users lower_bond,
+                                            enum ip_defrag_users upper_bond)
+{
+       return user >= lower_bond && user <= upper_bond;
+}
+#endif
+
+#ifndef HAVE_IP_DO_FRAGMENT
+static inline int rpl_ip_do_fragment(struct sock *sk, struct sk_buff *skb,
+                                    int (*output)(OVS_VPORT_OUTPUT_PARAMS))
+{
+       unsigned int mtu = ip_skb_dst_mtu(skb);
+       struct iphdr *iph = ip_hdr(skb);
+       struct rtable *rt = skb_rtable(skb);
+       struct net_device *dev = rt->dst.dev;
+
+       if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
+                    (IPCB(skb)->frag_max_size &&
+                     IPCB(skb)->frag_max_size > mtu))) {
+
+               pr_warn("Dropping packet in ip_do_fragment()\n");
+               IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
+               kfree_skb(skb);
+               return -EMSGSIZE;
+       }
+
+#ifndef HAVE_IP_FRAGMENT_TAKES_SOCK
+       return ip_fragment(skb, output);
+#else
+       return ip_fragment(sk, skb, output);
+#endif
+}
+#define ip_do_fragment rpl_ip_do_fragment
+#endif /* IP_DO_FRAGMENT */
+
+/* Prior to upstream commit d6b915e29f4a ("ip_fragment: don't forward
+ * defragmented DF packet"), IPCB(skb)->frag_max_size was not always populated
+ * correctly, which would lead to reassembled packets not being refragmented.
+ * So, we backport all of ip_defrag() in these cases.
+ */
+int rpl_ip_defrag(struct sk_buff *skb, u32 user);
+#define ip_defrag rpl_ip_defrag
+
+int __init rpl_ipfrag_init(void);
+void rpl_ipfrag_fini(void);
+#else /* OVS_FRAGMENT_BACKPORT */
+static inline int rpl_ipfrag_init(void) { return 0; }
+static inline void rpl_ipfrag_fini(void) { }
+#endif /* OVS_FRAGMENT_BACKPORT */
+#define ipfrag_init rpl_ipfrag_init
+#define ipfrag_fini rpl_ipfrag_fini
+
 #endif